n.e.quest vol 3 issue 3, october 2009

Newsletter of North East India Research Forum

N. E. Quest; Volume 3, Issue 3, October 2009 2

Newsletter Of

NORTH EAST INDIA RESEARCH FORUM

http://tech.groups.yahoo.com/group/northeast_india_research/ www.neindiaresearch.org



It is my great pleasure to be the volunteer editor of the NE Quest October

(2009) issue. At the outset, I owe my thankfulness to all the editorial team members as well as the forum members who have contributed to make the issue a successful realization. In this editorial I want to express some of my thoughts which are in my mind for quite sometime. It is always blamed governments for the slow industrial growth/ development of the north eastern region even though it has vast natural resources. But in my view, we have everything but lack of only good compatibility among the great personalities/ organizations of the region. All north eastern state has one central university each. North East India have IITG, NITs, research institutes of CSIR, DST, DBT, ISRO, medical institute like AIIMS (NEIGRIHMS), management institute like IIM, besides state universities and other academic/ research organizations. So we are not in a position to say that we do not have enough human resource or platform, but the question is how we are working for the development of the greater north eastern region.

If we want to see a developed north east India in very near future, it is the right time to work together dedicatedly. To initialize it, the senior personalities of well established organizations of north east might forward their hands together for better development of the region. As an example, persons from academia/ research organization as well as industry might work together along with government for the development of newer industries/organizations in the region. As north east region of India has most of the natural resources which can prosper it if the resources available could be properly utilized and exploited. Just to mention, it has huge bank of petroleum oil, coal, platinum, and many medicinally important plants. As a beginning, if north east could work for setting up organizations/industries mainly based on information technology and pharmaceuticals, it might bring back numerous brains of this region who are working presently in different parts of the globe. The recently established Biotech Park at Guwahati will definitely boost the region and serve as a pathfinder. We hope many more such organizations will flourish the north east in the near future. The improvement of any region is only possible if the people take utmost care to industrially develop such areas.

At last I wish North East India Research Forum a grand success and become

platform for such healthy scientific discussion in the days to come. I thank Dr. A. Adhikari for his great idea of creation of such a nice forum. Recently we have started forum cells in various universities and colleges of north east. Let us hope and wish that our forum be a platform for excellent scientific discussion and popularization of science among common peoples. Also I would like to thank all the members and editorial board members for their dedication to work together for the newsletter. We would specially like to thank Mr. Anirban (Panacea Studio, Pune) who has been designing the cover page of NE Quest from the inception of the newsletter. Many greetings to all!!

Pankaj Bharali



1. THE FORUM 5

2. SHORT BIOGRAPHY (P.C. Ray and S.S. Bhatnagar) 8

3. SCIENCE NEWS 10

4. NORTH EAST INDIANS MADE US PROUD 22

5. MEMBERS IN NEWS / FELLOWSHIP 23

6. INSTRUMENT OF THE ISSUE (Raman Spectrometer) 24 7. ARTICLES SECTION i) Two decades of electrochemistry research in the Department of Chemistry,

Gauhati University, India (Invited Article) 28 Diganta Kumar Das

ii) An insight on Hybrid nanocrystals 32

Sasanka Deka

iii) In-Vitro and Cryopreservation Techniques for Conservation of Microbial Resources 36 Debajit Thakur

iv) Cancer Drug Delivery and Challenges 44

Manashjit Gogoi v) A green or an evergreen revolution? Its time to think about neglected

and underutilized crops 47 Nabanita Bhattacharyya

8. THESIS ABSTRACT a) Studies on the Synthesis, Characterization, Surface Modification and

Application of Nanocrystalline Nickel Ferrite 50 B. Baruwati b) Synthesis, Structural Evaluation and Studies of Reactivity of

Heteroperoxovanadates (V) And Development of Solid acid Catalysts for Organic Transformations 55

S. K. Bharadwaj c) Preparation, Characterization, and Evaluation of Cerium Oxide Comprised

Novel Nanosized Composite oxides for Catalytic Applications 62 P. Saikia 9. MEMBER’S FACE 68

10. READER`S PAGE 71

11. HIGHER STUDY ABROAD 72

12. OPPORTUNITIES /ADVERTISEMENTS/CONFERENCES 73

13. THROUGH THE LENSE OF THE MEMBERS 76

CONTENTS



North East India Research Forum was created on 13

th November 2004.

1. How we are growing. Every forum has to pass through difficult phases at the time of birth. NE India Research Forum is also no exception. At the very beginning, it was a march hardly with few members (from chemistry only) and today the forum comprised of a force of more than 308 elite members. Now we are in a position such that people voluntarily come and join the group irrespective of disciplines.

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2. Discussions held in the forum • Necessity of directory of all the members of the forum. • Possibility of organising conference in the N. E. India. • Taking initiation on setting up of South East Asian Scientific Institute. • On selection of Best paper award. • Let us introspect. 3. Poll conducted and results • North East India is lacking behind the rest of the country due to-

1. Geographical constrain = 0% 2. Bad leadership = 40%

3. Lack of work culture = 36% 4. Corruption = 18% 5. Apathy from Central Govt. = 4%

• Which area of science is going to dominate by creating a great impact on society in next decade?

1.Nanoscience & nanotechnology = 22% 2. Biotechnology = 11% 3. Nanobiotechnology = 38% 4. Chemical Engineering = 0% 5. Medicine = 11% 6. Others = 16% 7. None = 0%

• Kindly let us know your view regarding the following topic. What activities of this group you like most?

1. Research articles = 33% 2. Information about vacancy/positions available = 10% 3. Way to have a contact with all

members = 29% 4. Scientific discussions = 14% 5. Others = 2%

• Selection of name for Newsletter There were total 36 proposals submitted by members of the forum for the Newsletter. The name proposed by Mr. Abhishek Choudhury, N.E. QUEST received the maximum number of votes and hence it is accepted as the name of the Newsletter. • How often should we publish our

newsletter '' N. E. Quest’’? 1. Every 3 months = 61% 2. Every 6 months = 38% 3. Once a year = 0%

4. Editors of Previous NE-Quest Issues 1. Vol 1 Issue 1 April, 2007

Editor: Dr. Arindam Adhikari 2. Vol 1 Issue 2 July 2007

Editor: Dr. Tankeswar Nath

1. THE FORUM


N. E. Quest; Volume 3, Issue 3, October 2009

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3. Vol 1 Issue 3 October 2007 Editor: Dr. Ashim Jyoti Thakur

4. Vol 1 Issue 4 January 2008 Editor: Mr. Pranjal Saikia

5. Vol 2 Issue 1 April 2008 Editor: Dr. Sasanka Deka

6. Vol 2 Issue 2 July 2008 Editor: Dr. Rashmi Rekha Devi

7. Vol 2 Issue 3 October 2008 Editor: Dr. Prodeep Phukan

8. Vol 2 Issue 4 January 2009 Editor: Dr. Manab Sharma

9. Vol 3 Issue 1 April 2009 Editor: Dr. Debananda Ningthoujam

10. Vol 3 Issue 2 July 2009 Editor: Dr. Robert Singh Thangjam

11. Vol 3 Issue 3 October 2009 (Current) Editor: Mr. Pankaj Bharali

5. A domain in the name of www. neindiaresearch.org is booked. 6. Future activities Proper planning and consequent implementation always play an important role in every aspect. Some of the topics / activities / suggestions which were being discussed, time to time in the forum will get top priorities in our future activities. Those are mentioned here, • Preparing complete online database of N.E. researchers with details. • Organising conference in the N.E. region-proposed by Dr. Utpal Bora. • Research collaboration among forum members. • Motivate student to opt for science education. • Help master’s students in doing projects in different organisation-proposed by Dr. Khirud Gogoi. • Supporting schools in rural areas by different ways. • Best paper awards.

• Compilation of book on ‘Education system of different countries’. Initiative for this project is taken by Dr. Mantu Bhuyan, NEIST, Jorhat, Assam

7. New activity • HiMedia Laboratories Pvt. Ltd is willing

to sponsor some future activities of the forum and have asked for space to advertise their products in the N. E. Quest. Starting from July issue (July 2009) N. E. Quest is providing one page for the advertisement. Details about this deal will be informed soon once finalised. Thanks to Dr. Robert Thangjam for his initiative in this matter.

• North East India Research Forum cells

have been started in the following universities and colleges,

Cell in the Dibrugarh University Contact: Dr. Jitu Ranjan Chetia Dept. of Chemistry Email: [email protected] Cell in Tezpur University Contact: Dr. Ashim J. Thakur Dept. of Chemistry Email: [email protected] Phone: +91 (3712) 267008/9/10 extn 5059 Cell in Manipur University Contact: Dr. Debananda S. Ningthoujam Coordinator, Microbial Biotech Lab Reader & Head Dept of Biochemistry Manipur University, Canchipur Imphal, India Email: [email protected] Cell in Mizoram University Contact: Dr. Thangjam Robert Singh Assistant Professor Department of Biotechnology Mizoram University Aizawl,India Email: [email protected] Phone: +91 389-2330861/2330859 (O)



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Cell in Govt. Science College, Jorhat (Jorhat Institute of Technology) Contact: Mr. Prasanta Kumar Bordoloi, Senior Lecturer Email: [email protected] Mobile: +91-9957036339 Cell in Arya Vidyapeth College, Guwahati Contact: Mr. Pabitra Kalita, Senior Lecturer Email: [email protected] Mobile No: +91-9613133859 & Dr. Pradip Bhattacharyya, Senior Lecturer Email: [email protected] Mobile No: +91-9864087494

To run the forum smoothly, to make it more organised and to speed up activities, formation of a committee/team is essential. The combined discussion of the moderators and senior members make the forum feel the importance of Advisors, co-ordinator, volunteer, webmasters etc. Of course it needs more discussion and will be approved by poll. 8. Guidelines for the forum The moderators formulated some guidelines for the forum which are as follow. These guidelines were kept open for discussion in the forum. With time and need the guidelines will be changed.

1. Anybody in the forum can start a meaningful and constructive discussion after discussion with moderators. 2. Comments from the individual members do not necessarily reflect the view of the forum. 3. No single moderator can take a crucial decision. All decision would be taken by the moderators unanimously or together with the group as majority. 4. One should not write any massage to the forum addressing some particular members. It should always start with Dear all / Dear esteemed members etc.

5. If one has to write a mail to a particular member she/he should write personal mail. 6. Everyone has the freedom to speak but that doesn’t mean that one should attack personally. Of course we do have differences. There can be debate or discussion, but it should always be a healthy one. One’s personal comment should be written in such a way that it reflects his/her view only. It should not touch other's sentiments/emotions. 7. Whenever we are in a forum, society, home, members should be sensitive / caring enough to their comments so that it does not hurt sentiment of any second members. 8. Members should not post greetings messages (Bihu wish, New Year wish etc) to the forum. 9. Members should post authentic news only. The source of the news should be authentic. No controversial news or comment should be posted to the forum. 10. Our main aim is to discuss science to generate science consciousness, scientific temperament, sensitivity, awareness and research for the benefit of the mankind in general and North East India in particular. 11. In severe cases, moderators can take a hard decision unanimously or majority wise (may be through poll). (This point needs to be accepted by all the members).

While sending request or while fulfilling request for articles please follow the following points.

• The forum has been formed to help each other. When a member requests articles/literature to forum, members of the forum are always happy to help the person by supplying the articles. But at this stage we have to keep in mind that the article should be sent to the person who requested it, not to the whole forum as it creates lots of unnecessary mails in the message box of the



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forum. Moreover if it continues, it become a irritation also for many members.

• It is also the duty of the person who requests article to acknowledge the person who helped him/her. This can be done by writing ' Request fulfilled by......' in the subject area while composing the mail and write a thanking message in the main message board. Once this is done, then if some other members want to send the article will know about the status of the request. This will also help members in keeping mailbox clean.

• Before asking for article, he/she should always check his/her institute/university libraries (online resources). If it is not available or accessible then only the member should request to the forum.

• Moreover sending articles (copyright protected articles) to the open forum violates copyright act. So please send the article to the person who requests not to everybody through this open forum.

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PANDIT JAWAHARLAL ON DR. S. S. BHATNAGAR I have always been associated with many prominent figures eminent in other ways, but Dr. Bhatnagar was a special combination of many things, added to which was a tremendous energy with an enthusiasm to achieve things. The result was he left a record of achievement which was truly remarkable. I can truly say that but for Dr. Bhatnagar you could not have seen today the chain of national laboratories.

----xxxx----

Sir Prafulla Chandra Ray (1861-1944)

Prafulla Chandra was born on 2 August 1861 in Raruli-Katipara, a village in the District of Khulna (in present Bangladesh). His early education started in his village school. He often played truant and spent his time resting comfortably on the branch of a tree, hidden under its leaves. After attending the village school, he went to Kolkata, where he studied at Hare School and the Metropolitan College. The lectures of Alexander Pedler in the Presidency College, which he used to attend, attracted him to chemistry, although his first love was literature. He continued to take interest in literature, and taught himself Latin and French at home. After obtaining a F.A. diploma from the University of Calcutta, he proceeded to the University of Edinburgh on a Gilchrist scholarship where he obtained both his B.Sc. and D.Sc. degrees. In 1888, Prafulla Chandra made his journey home to India. Initially he spent a year working with his famous friend Jagadish Chandra Bose in his laboratory. In 1889, Prafulla Chandra was appointed an Assistant Professor of Chemistry in the Presidency College, Kolkata. His publications on mercurous nitrite and its derivatives brought him recognition from all over the world. Equally important was his role as a teacher - he inspired a generation of young chemists in India thereby building up an Indian school of chemistry. Famous Indian scientists like Meghnad Saha and Shanti Swarup Bhatnagar were among his students. Prafulla Chandra believed that the progress of India

2. SHORT BIOGRAPHY



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could be achieved only by industrialization. He set up the first chemical factory in India, with very minimal resources, working from his home. In 1901, this pioneering effort resulted in the formation of the Bengal Chemical and Pharmaceutical Works Ltd. He retired from the Presidency College in 1916, and was appointed as Professor of Chemistry at the University Science College. In 1921 when Prafulla Chandra reached 60 years, he donated, in advance, all his salary for the rest of his service in the University to the development of the Department of Chemistry and to the creation of two research fellowships. The value of this endowment was about two lakh rupees. He eventually retired at the age of 75. In Prafulla Chandra Ray, the qualities of both a scientist and an industrial entrepreneur were combined and he can be thought of as the father of the Indian Pharmaceutical industry. Shanti Swarup Bhatnagar (1894-1955)

Dr. Shanti Swaroop Bhatnagar is a well-known scientist. He is remembered for having established various chemical laboratories in the country known as `The Father of Research Laboratories`. He used to spend all his spare time in his laboratory doing research. He established a total twelve national laboratories such as `Central Food Processing Technological Insitute` Mysore; `National Chemical Laboratory` Pune; `the National Physical Laboratory` New Delhi; `the National Metallurgical Laboratory` Jamshedpur; `the Central Fuel Institute` Dhanbad just to name a few.

This Indian scientist was born on 21st February 1894 in Shahpur now in Pakistan. When he was only eight months old his father died. While spending his time in the maternal house with engineer grandfather, a liking for science and engineering was developed within him. He also inherited the gift of poetry from his maternal family. `Karamati` one-act play in Urdu written by him won the first prize in a competition. This eminent scientist died on 1st January 1955 in New Delhi, India. After completing Master`s Degree in India he went to England on a research fellowship. In 1921 he received D.Sc from London University. He joined `Benaras Hindu University` as Professor. As a reward for his research in science British Government `Knighted` in the year 1941. He was elected as a Fellow of the Royal Society on 18th march 1943. Dr. Bhatnagar`s research interest includes emulsions, colloids and industrial chemistry. Emulsion is a mixture of two unblendable substances one substance is dispersed in the other. Like butter and margarine, espresso etc. A colloid is a type of homogenous mixture i.e. mixtures that have definite, true composition and properties. But his fundamental contributions were in the field of magneto-chemistry. He used magnetism as a tool to know more about chemical reactions. Accompanied with Physicist R.N Mathur, Dr. Shanti S. Bhatnagar designed "The Bhatnagar-Mathur Interference balance". A British firm manufactured their designed structure. Dr. Bhatnagar also composed a beautiful `kulgeet` (University song) which sung with great reverence prior to functions held in the university. As Nehru was much in favor of scientific development after Independence, "Council of Scientific and Industrial Research" was set up under the chairmanship of Dr. Bhatnagar. . He became the first director-general of the Council of Scientific and Industrial Research (CSIR) in 1940. Later, he was awarded `Padma Bhushan`. After his death, CSIR established a Bhatnagar Memorial award for eminent scientists in his honor.



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Nobel Prize in Science, 2009 The Nobel Prize in Chemistry for 2009 awards studies of one of life's core processes: the ribosome's translation of DNA information into life. Ribosomes produce proteins, which in turn control the chemistry in all living organisms. As ribosomes are crucial to life, they are also a major target for new antibiotics.

This year's Nobel Prize in Chemistry awards Venkatraman Ramakrishnan, Thomas A. Steitz and Ada E. Yonath (view clockwise in photograph) for having showed what the ribosome looks like and how it functions at the atomic level. All three have used a method called X-ray crystallography to map the position for each and every one of the hundreds of thousands of atoms that make up the ribosome. Inside every cell in all organisms, there are DNA molecules. They contain the blueprints for how a human being, a plant or a bacterium, looks and functions. But the DNA molecule is

passive. If there was nothing else, there would be no life. The blueprints become transformed into living matter through the work of ribosomes. Based upon the information in DNA, ribosomes make proteins: oxygen-transporting haemoglobin, antibodies of the immune system, hormones such as insulin, the collagen of the skin, or enzymes that break down sugar. There are tens of thousands of proteins in the body and they all have different forms and functions. They build and control life at the chemical level. An understanding of the ribosome's innermost workings is important for a scientific understanding of life. This knowledge can be put to a practical and immediate use; many of today's antibiotics cure various diseases by blocking the function of bacterial ribosomes. Without functional ribosomes, bacteria cannot survive. This is why ribosomes are such an important target for new antibiotics. This year's three Laureates have all generated 3D models that show how different antibiotics bind to the ribosome. These models are now used by scientists in order to develop new antibiotics, directly assisting the saving of lives and decreasing humanity's suffering. This year's Nobel Prize in Physics is awarded for two scientific achievements that have helped to shape the foundations of today’s networked societies. They have created many practical innovations for everyday life and provided new tools for scientific exploration. In 1966, Charles K. Kao (extreme left in photograph, view clockwise) made a discovery that led to a breakthrough in fiber optics. He carefully calculated how to transmit

3. SCIENCE NEWS



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light over long distances via optical glass fibers. With a fiber of purest glass it would be possible to transmit light signals over 100 kilometers, compared to only 20 meters for the fibers available in the 1960s. Kao's enthusiasm inspired other researchers to share his vision of the future potential of fiber optics. The first ultrapure fiber was successfully fabricated just four years later, in 1970. Today optical fibers make up the circulatory system that nourishes our communication society. These low-loss glass fibers facilitate global broadband communication such as the Internet. Light flows in thin threads of glass, and it carries almost all of the telephony and data traffic in each and every direction. Text, music, images and video can be transferred around the globe in a split second. If we were to unravel all of the glass fibers that wind around the globe, we would get a single thread over one billion kilometers long – which is enough to encircle the globe more than 25 000 times – and is increasing by thousands of kilometers every hour.

A large share of the traffic is made up of digital images, which constitute the

second part of the award. In 1969 Willard S. Boyle and George E. Smith (extreme right and down in photograph, view clockwise) invented the first successful imaging technology using a digital sensor, a CCD (Charge-Coupled Device). The CCD technology makes use of the photoelectric effect, as theorized by Albert Einstein and for which he was awarded the 1921 year's Nobel Prize. By this effect, light is transformed into electric signals. The challenge when designing an image sensor was to gather and read out the signals in a large number of image points, pixels, in a short time. The CCD is the digital camera's electronic eye. It revolutionized photography, as light could now be captured electronically instead of on film. The digital form facilitates the processing and distribution of these images. CCD technology is also used in many medical applications, e.g. imaging the inside of the human body, both for diagnostics and for microsurgery. Digital photography has become an irreplaceable tool in many fields of research. The CCD has provided new possibilities to visualize the previously unseen. It has given us crystal clear images of distant places in our universe as well as the depths of the oceans. This year´s Nobel Prize in Physiology or Medicine is awarded to three scientists namely Elizabeth Blackburn, Jack Szostak and Carol Greider (view clockwise in photograph), who have solved a major problem in biology: how the chromosomes can be copied in a complete way during cell divisions and how they are protected against degradation. The Nobel Laureates have shown that the solution is to be found in the ends of the chromosomes – the telomeres – and in an enzyme that



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forms them – telomerase. The long, thread-like DNA molecules that carry our genes are packed into chromosomes, the telomeres being the caps on their ends. Elizabeth Blackburn and Jack Szostak discovered that a unique DNA sequence in the telomeres protects the chromosomes from degradation. Carol Greider and Elizabeth Blackburn identified telomerase, the enzyme that makes telomere DNA. These discoveries explained how the ends of the chromosomes are protected by the telomeres and that they are built by telomerase.

If the telomeres are shortened, cells age. Conversely, if telomerase activity is high, telomere length is maintained, and cellular senescence is delayed. This is the case in cancer cells, which can be considered to have eternal life. Certain inherited diseases, in contrast, are characterized by a defective telomerase, resulting in damaged cells. The award of the Nobel Prize recognizes the discovery of a fundamental mechanism in the cell, a discovery that has stimulated the development of new therapeutic strategies.

Capturing sun rays in space to light up Japan

AFP, 2009, Tokyo (Source: Times of India) It may sound like a sci-fi vision, but Japan’s space agency is dead serious: by 2030 it wants to collect solar power in space and zap it down to Earth, using laser beams or microwaves. The government has just picked a group of firms and a team of researchers tasked with turning the ambitious, multi-billion-dollar dream of unlimited clean energy into reality in coming decades. Japan has long been a leader in solar and other renewable energies and this year set ambitious greenhouse gas reduction targets. But Japan’s boldest plan to date is the Space Solar Power System (SSPS), in which arrays of photovoltaic dishes several square kilometres in size would hover in geostationary orbit outside Earth’s atmosphere. “Since solar power is a clean and inexhaustible energy source, we believe this system will help solve the problems of energy shortage and global warming,” researchers at Mitsubishi Heavy Industries, one of the project participants, wrote in a report. The solar cells would capture the solar energy, which is at least five times stronger in space than on Earth, and beam it down to the ground through clusters of lasers or microwaves. These would be collected by gigantic parabolic antennae, likely to be located in restricted areas at sea or on dam reservoirs, said Tadashige Takiya, a spokesman at the Japan Aerospace Exploration Agency (JAXA). The researchers are targeting a one gigawatt system, equivalent to a medium-sized atomic power plant that



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would produce electricity at eight yen per kilowatt-hour, six times cheaper than its current cost in Japan. The challenge including transporting the components to space — may appear gigantic, but Japan has been pursuing the project since 1998, with some 130 researchers studying it under JAXA’s oversight. The project’s roadmap outlined several steps that would need to be taken before a full-blown launch in 2030. Within several years, “a satellite designed to test the transmission by microwave should be put into low orbit with a Japanese rocket,” said Tatsuhito Fujita, one of the JAXA researchers heading the project. The next step, expected around 2020, would be to launch and test a large flexible photovoltaic structure with 10 megawatt power capacity, to be followed by a 250 megawatt prototype. This would help evaluate the project’s financial viability, say officials. The final aim is to produce electricity cheap enough to compete with other alternative energy sources. JAXA says the transmission technology would be safe but concedes it would have to convince the public, which may harbour images of laser beams shooting down from the sky, roasting birds or slicing up aircraft in mid-air.

Lab-made organ works in siring kid?

REUTERS 2009, Washington (Source: Times of India) Researchers have engineered artificial penises in rabbits, using cells from the animals, who then used their new organs to father baby rabbits.

It provides a tailor-made transplant, said Anthony Atala of Wake Forest University Baptist Medical Center’s Institute for Regenerative Medicine, who led the study. “Once the tissue is there, the body recognizes the tissue as its own,” Atala said. Atala focused on the penis because he is a pediatric urologist, who has specialized for years in disorders and congenital defects of the bladder and sexual organs. “That was the inspiration for this work. We are seeing babies born with deficient genitalia all the time. There are no good options,” Atala said. He is also a specialist in regenerative medicine, which uses the body’s own cells to repair damage. In this case, Atala’s team used ordinary cells, not the stem cells often used in such research. Companies such as Geron and privately held Advanced Cell Technology have business models based on such technology. Atala’s team first created a scaffold using the penis of a rabbit, and removed all the living cells from it, leaving only cartilage. They then took a small piece of tissue from the penis of another rabbit and grew the cells in a lab dish. Atala said the work has taken his team 18 years to complete. “We had to find the right growth factors, the right soup to grow the cells in,” he said. They made sure to have two cell types, smooth muscle cells and endothelial cells, the same type of cells that line blood vessels. The smooth muscle cells made the organ’s spongy tissue and the endothelial cells grew into blood vessels — very important in an organ like the penis, which requires good blood supply. The cells were seeded onto the scaffold, and six weeks later the researchers had penises to graft



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onto rabbits that had their penises removed. The animals seemed to realize they had working organs again — the 12 with the grafts tried to mate with female rabbits within one minute of being put into cages with them, and four of the female rabbits became pregnant. Those with the scaffolding alone and no working tissue did not even try. Atala is hoping the procedure will work with people, perhaps starting with adult men who have had damage to their organs. “Patients with congenital anomalies, penile cancer, traumatic penile injury, and some types of organic erectile dysfunction could benefit from this technology in the future,” the team wrote in the report. The process takes six weeks from beginning to end, he said, and there is reason to believe a penis grafted onto a baby would grow with the child. Atala hopes the approach will work with other organs. “We have made clitoral tissue in the past,” he said. Atala’s team started their experiments with replacement bladders grown from patients' cells. Patients fitted with artificial bladders have been enjoying good function for 10 years now, Atala said.

Drug with dual benefits for heart

(Source: The Hindu)

A study led by an Indian-origin researcher has found that a drug that raises levels of ‘good’ cholesterol can also help clear clogged arteries in heart patients who are already on standard statin therapy, Oxford University announced recently.

The findings of the study, led by Robin Choudhury of the department of cardiovascular medicine at Oxford University, are published in this week’s issue of the Journal of the American College of Cardiology.

This is an exciting find because it gives a new opportunity to treat cardiovascular patients, Choudhury told IANS. This is the first clear evidence that a therapy to raise levels of good cholesterol when taken alongside statins can have a beneficial effect.

The researchers used MRI scans to show a reduction in the clogging of artery walls in patients after a year of treatment with niacin, a B vitamin commonly used to raise levels of high-density lipoprotein (HDL) or ’good’ cholesterol. Choudhury, whose father is a retired surgeon at Nilratan Sircar Hospital in Kolkata, said if the findings are borne out in ongoing larger studies, this could benefit large numbers of people worldwide. A third to a quarter of all heart patients have low levels of good cholesterol, but niacin fell out of favour after being shown to be useful in the early days of heart treatment, as statin became more common. Heart disease is the biggest killer in the Western world, and atherosclerosis the ‘furring up’ or hardening of arteries is closely linked to later heart attacks and strokes.

The standard treatment for patients with atherosclerosis is to be prescribed statins, which lower the levels of ‘bad’ cholesterol, which might otherwise get deposited in the arteries. ‘Good’ cholesterol is thought to help remove bad cholesterol from the arteries.

The Oxford researchers, who worked with colleagues from Manchester University, found that after a year of



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niacin therapy the size of clogged artery walls in heart patients thinned down by an average of 1.1 sq mm, while those receiving a placebo saw an average increase of 1.2 sq mm.

Patients on niacin showed an average 23 per cent increase in levels of good cholesterol and a reduction in bad cholesterol of 19 per cent. Our results are very encouraging in that they have shown a very definite potential benefit, and will certainly increase the great interest in the large outcome studies that are due to report in the next couple of years, he added. Two such studies will report their results in the next few years.

Heating, Air-Conditioning and Carpets May Be Hazardous To Your Health (Source: ScienceDaily, 2009) Damp environments, poorly maintained heating and air-conditioning systems and carpeting may contribute to poor indoor air quality, according to experts at the annual meeting of the American College of Allergy, Asthma and Immunology (ACAAI) in Miami Beach, Fla. Americans spend about 90 percent of their time indoors, where they are repeatedly exposed to indoor allergens and airborne particles that can lead to respiratory symptoms and conditions. Damp Buildings "If there was just one thing I could do to fix buildings, it would be to change the relative humidity," said Doug Garrett, CEM, CDSM, building scientist and president of Building Performance and Comfort, Leander, Texas. "Moisture leads to conditions that are conducive to dust mites and

mold, as well as bacteria, yeast and other living organisms." Garrett pointed to dust mites and mold as particularly worrisome. A damp building with high humidity may lead to increased levels of dust mites and mold, leading to increased allergic respiratory symptoms, as well as the worsening of asthma. And even if someone is not allergic, molds may produce mycotoxins and volatile organic chemicals (VOCs) that smell bad and may cause respiratory irritation, he said. Dust mites are microscopic arachnids that thrive in humidity. They cause allergic reactions and trigger asthma symptoms. Nearly half of all young people with asthma are allergic to dust mites; about 10 percent of the population is allergic to dust mites. Mold requires moisture to grow. Indoor environments house many sources of moisture including condensation and leaky pipes. Indoor Breathing Environment Although there are many culprits that negatively affect indoor air quality, poorly maintained air-conditioning and carpeting are among the most problematic. "A home's heating and air-conditioning (HVAC) system, if poorly maintained, can become a major source of microbial allergens," said Garrett. According to Garrett, up to 30 percent of the air inside a home can come from the attic, parking garage or basement. One study supported by the EPA found that 75 percent of homes had carbon monoxide from the garage inside of the home. Like air conditioning systems, carpeting often harbors allergens, including dust mites and molds said Jeffrey May, M.A., principal scientist of May Indoor Air Investigations LLC,



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Tyngsborough, Mass. Organisms and particles that become airborne eventually settle in carpeting. In damp environments, carpeting provides an ideal environment for mold growth. "Many schools shampoo their carpeting right before school starts at the end of summer when it's humid outside," said May. "There couldn't be a worse time." Making a Healthier Indoor Environment To improve indoor air quality, Garrett lists several construction practices that, when done right, can make a significant difference. These include installing tight ductwork, achieving airtight construction, using a correctly sized HVAC (heating, ventilation and air conditioning) system and making sure there is fresh air ventilation. Proper ventilation involves introducing air from a known source and then filtering, dehumidifying and pre-cooling or heating it. "You can't build houses too airtight," said Garrett. "But you can under ventilate them." Once built, maintenance becomes key. May offers the following advice for home owners on making their indoor environments healthier: • Keep the air conditioner clean. Use a filter with an American Society of Heating and Air-Conditioning Engineers (AHRAE) Standard MERV (Minimum Efficiency Reporting Value) of at least 8. • Do not have carpeting in any buildings or homes where humidity can't be controlled. If you cannot replace carpet, vacuum thoroughly, carefully and methodically so you don't stir dust into the air. Use a vacuum with a HEPA filter or cyclonic vacuum. • Prevent mold by dehumidifying the basement. In unfinished basements, humidity should be kept lower than 50 percent. Do research before buying a dehumidifier. "There are scams out

there" said May. "And 'exhaust only' systems are not effective." Nanoparticles' indirect threat to DNA By Janet Raloff (Source: www.scincenews.org, 2009) Tiny metal nanoparticles can damage DNA, essentially by triggering toxic gossip. Researchers from throughout the United Kingdom took part in a series of tests in which they separated toxic metal nanoparticles from potentially vulnerable test cells — what I’ll refer to as cellular guinea pigs. In some cases the barrier was a piece of plastic, other times a four-cell-thick, intact wall of tissue. Although the plastic wall protected the guinea pigs, “We found there was as much damage on the [far] side of the cellular barrier as there was if a barrier hadn’t been there in the first place,” observes C. Patrick Case, a researcher and pathologist at Southmead Hospital in Bristol, England. The finding, he admits, was “a huge surprise.” Particularly since the billionth-of-a-meter-scale particles appear to have wreaked their havoc indirectly. When tests indicated the nanoparticles were not breaching the cellular wall, Case’s team began probing for evidence of some type of cellular signaling that might relay a damaging message to the DNA of cells on the opposite side. And indeed, the researchers report today in Nature Nanotechnology, the metal nanoparticles triggered the generation of ATP, a known signaling molecule, within cells of the barrier wall. ATP — and perhaps a chorus of related, but as yet unrecognized signaling molecules — whispered their chemical vitriol to neighboring cells. The final layer of that wall then spit out its toxic message, which triggered



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within the hapless guinea-pig cells a splitting of one or more of the outer rails in their DNA’s ladderlike structure. The damage was bad — but also improbable. Keep in mind, Case warns, “We were not trying to model what happens in humans.” For instance, the UK scientists used unreal concentrations of nanoparticles. They also acknowledge that animals and people have evolved repair mechanisms to splice damaged DNA back together or to cull affected cells. However, those repair systems do sometimes become overwhelmed, repairing the DNA shoddily or allowing somewhat damaged DNA to persist. In these circumstances, disease — notably cancer — may develop. Working in an orthopedics department, the team's leaders also didn’t design their tests to use garden variety nanoparticles: carbon nanotubes or beads of nanosilver. Instead, they took tiny pieces of the cobalt-chromium alloy used in joint-replacement parts. Over time, shavings can wear off and end up surrounding joints, and perhaps even become excreted. The researchers also didn’t recruit ordinary, healthy cells as their guinea pigs but an experimental line — known as BeWo — which has been derived from placental cells. In the future, Case says, his team plans to work with more conventional nanomaterials and in experimental systems that may better predict whether and how such teensy bits might prove toxic to the body. How leaves could monitor pollution By Sid Perkins (Source: www.scincenews.org, 2009) Foliage on trees lining traffic routes could serve as low-tech pollution sensors, a new analysis suggests.

The exhaust of many vehicles, particularly those that burn diesel, includes copious quantities of microscopic particles of many sizes. Although particles larger than 10 micrometers in diameter are efficiently filtered by the upper respiratory system, those smaller than 2.5 micrometers across can reach areas deep within the human lung to trigger disease and inflammation, says Bernard Housen, a geophysicist at Western Washington University in Bellingham. When Housen and university colleague Luigi Jovane analyzed leaves collected at several sites along streets in Bellingham, they found that the leaves along bus routes were as much as 10 times more magnetic than leaves collected on quieter residential streets. That boost in magnetism came from iron oxide particles in emissions that were trapped on the microscopically rough surface of the leaves, Housen reported October 18 at the annual meeting of the Geological Society of America. Iron oxide particles smaller than 2.5 micrometers across are typically magnetic, while those larger than 10 micrometers aren’t. Rain washes away no more than 30 percent of all the particles stuck on a leaf, and even ultrasonic vibrations can’t fully cleanse the surface. These characteristics make tree leaves a good candidate for pollution monitoring, Housen says. Other pluses: Leaves are cheap, and they provide information about the air near ground level where people are, not high above the street where most air quality monitoring equipment is installed. Scientists still must figure out how the number of iron oxide particles trapped by leaves relates to the total number of particles of different chemical classes in the air, says Housen. Because many air quality standards are based on exposures for short periods of time,



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such as eight-hour or 24-hour intervals, researchers must also figure out how to estimate short-term air quality from leaves, which accumulate particles throughout their growth. Scientists Decipher the Formation of Lasting Memories (Source: ScienceDaily, 2009) Researchers at Karolinska Institutet have discovered a mechanism that controls the brain's ability to create lasting memories. In experiments on genetically manipulated mice, they were able to switch on and off the animals' ability to form lasting memories by adding a substance to their drinking water. The findings, which are published in the scientific journal PNAS, are of potential significance to the future treatment of Alzheimer's and stroke. "We are constantly being swamped with sensory impression," says Professor Lars Olson, who led the study. "After a while, the brain must decide what's to be stored long term. It's this mechanism for how the connections between nerve fibers are altered so as to store selected memories that we've been able to describe." The ability to convert new sensory impressions into lasting memories in the brain is the basis for all learning. Much is known about the first steps of this process, those that lead to memories lasting a few hours, whereby altered signalling between neurons causes a series of chemical changes in the connections between nerve fibers, called synapses. However, less is understood about how the chemical changes in the synapses are converted into lasting memories stored in the cerebral cortex. A research team at Karolinska Institutet has now discovered that

signalling via a receptor molecule called nogo receptor 1 (NgR1) in the nerve membrane plays a key part in this process. When nerve cells are activated, the gene for NgR1 is switched off, and the team suspected that this inactivation might be important in the creation of long-term memories. To test this hypothesis they created mice with an extra NgR1 gene that could remain active even when the normal NgR1 was switched off. "Doing this, we found that the ability to retain something in the memory for the first 24 hours was normal in the genetically modified mice," says Professor Olson. "However, two different memory tests showed that the mice had serious difficulties converting their normal short-term memories to long-term ones, the kind that last for months." In order to be able to switch the extra NgR1 gene on and off, the group attached a regulatory mechanism to the gene that reacted to a harmless additive in their drinking water. When the extra gene was then switched off, the mice retained their normal ability to form long-term memories. By subsequently switching it off at different times after a memory-forming event, they were able to pinpoint the effect of the NgR1 gene to the first week after such an event. "We know that concussion can cause someone to forget events that occurred in the week before the injury, what we call retrograde amnesia, even though they can remember events that occurred earlier than about a week before. This we believe tallies with our findings," says Alexandra Karlén, one of the scientists involved in the study. The scientists hope that their findings will eventually be of use in the development of new treatments for memory impairments, such as those related to Alzheimer's and stroke. Medicines designed to target the NgR1 receptor system would be able to



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improve the brain's ability to form long-term memories. The studies were conducted in collaboration with American researchers at the National Institute on Drug Abuse (NIDA), NIH. Terrific Discovery: India Finds Water on Moon (September 25, 2009) The decades-long debate is over now and it is confirmed that the polar regions of the Moon has water. Built, launched and operated by the Indian Space Research Organization, Chandrayaan-1 has found water on the lunar surfaces. India's first moon mission Chandrayaan-1 was launched with the prime objective of finding traces of water on the lunar surface besides mapping minerals and chemicals on the Moon. With over 24 hrs of speculations, NASA has confirmed the presence of water molecules in the polar regions of the moon, in its press conference. Towards this, a host of sophisticated instruments were included in Chandrayaan-1 spacecraft, like Moon Impact Probe (MIP) and Hyper-Spectral Imager (HySI) from ISRO as well as Moon Mineralogy Mapper (M3) and Miniature Synthetic Aperture Radar (Mini-SAR) through NASA to collect relevant data from the lunar surface. M3 was carried into space on 22 October 2008, aboard the Chandrayaan-1 spacecraft. Data from the Visual and Infrared Mapping Spectrometer, or VIMS, on NASA's Cassini spacecraft, and the High-Resolution Infrared Imaging Spectrometer on NASA's Epoxi spacecraft contributed to confirmation of the finding. The spacecraft imaging spectrometers made it possible to map lunar water more effectively than ever before, says NASA. During the mission, excellent quality of data from all these instruments has

been obtained. While M3 has covered nearly 97 per cent of the lunar surface, some of the other instruments have covered more than 90 per cent, added ISRO. "A path-breaking finding has evolved recently from the detailed analysis of the data obtained from M3, which has clearly indicated the presence of water molecules on the lunar surface extending from lunar poles to about 60 degree. Latitude. Hydroxyl, a molecule consisting of one oxygen atom and one hydrogen atom, was also found in the lunar soil. The confirmation of water molecules and hydroxyl molecule in the moon's polar regions raises new questions about its origin and its effect on the mineralogy of the moon," ISRO said in its release. The scientific team, after detailed analysis, has come to the conclusion that there are traces of hydroxyl (OH) and water (H2O) molecules on the surface of the moon closer to the polar region. It is also concluded that they are in the form of a thin layer embedded in rocks and chemical compounds on the surface of the moon and the quantity is also extremely small of the order of about 700 ppm. These molecules could have come from the impact of comets or radiation from the Sun. But most probable source could be low energy hydrogen carried by solar wind impacting on the minerals on lunar surface. This in turn forms OH or H2O molecules by deriving the oxygen from metal oxide. Analysis of data from other instruments on board Chandrayaan-1 is in progress. "Water ice on the moon has been something of a holy grail for lunar scientists for a very long time," said Jim Green, director, planetary science division, NASA Headquarters in Washington. "This surprising finding



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has come about through the ingenuity, perseverance and international cooperation between NASA and the India Space Research Organization." The confirmation of elevated water molecules and hydroxyl at these concentrations in the moon's polar regions raises new questions about its origin and effect on the mineralogy of the moon. Answers to these questions will be studied and debated for years to come. US spacecraft set for Moon crash Nasa is set to crash two unmanned spacecraft into the Moon in a bid to detect the presence of water-ice. A 2,200kg rocket stage will be first to collide, hurling debris high above the lunar surface. A second spacecraft packed with science instruments will analyse the contents of this dusty cloud before meeting a similar fate. The identification of water-ice in the impact plume would be a major discovery, scientists say. Not least because a supply of water on the Moon would be a vital resource for future human exploration. The $79m (£49m; 53m euro) mission is called LCROSS (the Lunar Crater Observation and Sensing Satellite). Greg Schmidt, deputy director of the US space agency's Lunar Science Institute said: "We're attempting to answer here one of the most important remaining questions for both science and future exploration: Has water been deposited on the Moon in major quantities?" "We're doing the LCROSS mission in a new low-cost way that can serve as a pathfinder for future missions Nasa is interested in doing." The existence of water-ice in permanently shadowed craters at the lunar poles had previously been postulated by scientists, but never confirmed.

ISRO Launches 7 Satellites in 20 Minutes (September 24, 2009) After the untimely loss of its lunar mission Chandrayaan, the Indian Space Research Organisation (ISRO) has once again proved its capabilities. India's Polar Satellite Launch Vehicle, PSLV-C14, in its 16th mission launched 958 kg Oceansat-2 and six nano-satellites into a 720 km intended Sun Synchronous Polar Orbit (SSPO) on 23 September 2009. The Oceansat-2 satellite mainframe systems derive their heritage from previous IRS missions and launched by PSLV-C14 from Satish Dhawan Space Centre, Sriharikota. Oceansat-2 carries three payloads including an Ocean Colour Monitor (OCM-2), Ku-band Pencil Beam scatterometer (SCAT), developed by ISRO; and Radio Occultation Sounder for Atmosphere (ROSA) developed by the Italian Space Agency. Oceansat-2 is envisaged to provide continuity of operational services of Oceansat-1(IRS-P4) with enhanced application potential. The main objectives of OceanSat-2 are to study surface winds and ocean surface strata, observation of chlorophyll concentrations, monitoring of phytoplankton blooms, study of atmospheric aerosols and suspended sediments in the water. Apart from Oceansat-2, four CUBESATs and two RUBIN are the foreign satellites launched by PSLV-C14 on 23 September. The four CUBESATs are educational satellites from European universities, each weighing around one kg and developed to perform technology demonstration in space. The satellites are launched inside a Single Picosatellite Launcher (SPL) also weighing one kg, which is a dedicated European launch adaptor to deploy a CubeSat.



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RUBIN-9 consists of two spacecrafts Rubin-9.1 and Rubin-9.2 weighing 8kg each and will primarily be used for the Automatic Identification System (AIS) for maritime applications. These are non-separable payloads that will be mounted at an angle of 45deg to the PSLV EB deck. Rubin-9.1 is developed by Luxspace and has a mission objective of providing an insight into the issue of message collisions that limit detection in areas of dense shipping. The main purpose of the Rubin-9.2 spacecraft is to test and qualify nano technologies from Angstrom company Sweden and to continue space based maritime Automatic Identification System (AIS) receiver experiments (started with Rubin-7 and Rubin-8 missions). Rubin-9.2 is similar to the Rubin-8 launched on PSLV-C9 in April 2008. Commenting on this milestone, the President of India, Pratibha Devisingh Patil has congratulated the Indian Space Research Organisation for successfully placing seven satellites in Earth orbit, after the launch of PSLV C14. She said, "ISRO's capabilities have once again been highlighted through this launch and the placement of these satellites in safe Earth orbit." She is confident that Oceansat-2 will provide valuable data on the climate, as the satellite studies the interaction between the oceans and the atmosphere. India to Undertake Mars Mission between 2013 And 2015 (September 01, 2009) India's first unmanned lunar mission, Chandrayaan-1, may have been abandoned after the country's national space agency lost radio contact with the spacecraft on Saturday. But Indian astronauts are now gearing up for bigger challenges with the Indian

Space Research Organisation (ISRO) announcing plans to launch its first mission to Mars sometime between 2013 and 2015. The space agency says it has begun preparations for sending a spacecraft to Mars to explore the red planet in quest of its space ambitions. G. Madhavan Nair, chairman, ISRO yesterday told local media in Panaji, capital of the western state of Goa, "We have given a call to international agencies to submit their proposals. We will be able to plan our mission depending on the type of experiments they propose to conduct." In August, the Government had sanctioned Rs 10 crores for the project. Instead of the Polar Satellite Launch Vehicle (PSLV) used in the lunar mission, the Geosynchronous Satellite Launch Vehicle (GSLV) would be used for the Mars project and placing the spacecraft to its orbit. ISRO may even use nuclear power to propel the craft towards Mars. ISRO is also making efforts to bring down the cost of the Mars mission, as was done with the Chandrayaan-1 mission, which cost less than $100 million. Moreover, the space agency will tap a lot of young scientists for the Mars mission, particularly from the Indian Institute of Space Technology, the Physical Research Laboratory, Tata Institute of Fundamental Research and other research laboratories. Madhavan Nair has been elected as the president of the International Academy of Astronautics (IAA). Nair has also become the only Indian and the first non-American to head the renowned scientific body. Nair, who is presently IAA's vice president for scientific activities, will take over from Edward Stone, during the International Astronautical Congress to be held in Korea later this year.

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1. Professor Okhil Kumar Medhi

Prof. Okhil Kumar Medhi is presently serving as the Vice-Chancellor of Gauhati University, Guwahati. He also served as the Dean of the Faculty of Science, besides being a former Head of the Chemistry Department of Gauhati University. Prof. Medhi did his M.Sc. and Ph.D. from Indian Institute of Technology, Kanpur. He was a Post Doctoral Researcher at Essex University United Kingdom on a Commonwealth Academic Fellowship. He was also a visiting fellow to Tata Institute of Fundamental Research (TIFR), Mumbai and worked as University Grants Commission (UGC) National Associateship. He joined North Eastern Hill University (NEHU) Shillong as a Lecturer (1980-1983) and latter moved to Gauhati University, Guwahati where he became full professor in 1991. His research areas are Bioinorganic and Biomimetic Chemistry, Electron Transfer across Charged Interfaces, and Micelles and Membrane Systems. He is an active member of many scientific professional bodies including Indian Society for Surface Science and Technology, Kolkata. Recently he co-authored one of the most studied Inorganic Chemistry text book, Inorganic Chemistry: Principles, Structure and Reactivity (Pearson, 2006, New Delhi): JE Huheey, EA Keiter, RL Keiter, O.K. Medhi.

2. Professor (Ms) Joyanti Chutia

Prof. Joyanti Chutia is presently serving as the Director of Institute of Advanced Study in Science and Technology (IASST), Guwahati. She did her graduate and post graduate courses in Cotton College, Guwahati and Dibrugarh University, Dibrugarh, respectively. She obtained University Grants Commission (UGC) fellowship in 1976, studying conduction mechanism in thin polymer films. In 1980, she went to the International Centre for Theoretical Physics, Italy to attend a research course on Polymer Physics and Liquid Crystals for three months. Later on she completed her Ph.D. in 1981 and continued her research as CSIR-postdoctoral fellow in Dibrugarh University. She also worked in Institute of Plasma Research, Gandhinagar and spent nearly two years in Plasma Physics Program being carried out first in Physical Research Laboratory, Ahmedabad before joining IASST. In 1988 she went to work in the Plasma Laboratory of the Institute of Space and Astronautical Science, Tokyo under the supervision of Dr. Y. Nakamura. Her research work involved low frequency instability in low temperature plasma and propagation and reflection of solitary waves. She is an FNASc, is a recipient of the Durlav Deka Memorial Award, the Basanti Bordoloi Award, the Sadhani Saurya Award, the Ghanashyam Goswami Award, and the K K Barua National Award.

4. NORTHEAST INDIANS MADE US PROUD



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Md. Harunar Rashid has recently joined KAUST-Cornell Center for Energy and Sustainability, Cornell University, USA as Postdoctoral Visiting Scientist. Before his postdoctoral assignment he was a senior research fellow at Materials Science Division, Indian Association for the Cultivation of Science, Kolkata. He submitted his thesis to Jadavpur University, Kolkata working under the guidance of Dr. T. K. Mandal. Dr. Diganta Sarma recently joined the Department of Medicinal Chemistry, University of Kansas, USA as a postdoctoral research associate. Prior to this postdoctorate assignment he worked in the Department of Medicinal Chemistry, Kyoto Pharmaceutical University, Japan as a JSPS postdoctoral fellow w.e.f. 2007. Dr. Sarma was a PhD scholar of National Chemical Laboratory, Pune before joining as JSPS postdoctoral fellow. Dr. Pranjal Kumar Kalita will be joining as a Post Doctoral Fellow in January 2010 at Iowa State University, USA. He was a postdoctoral research scientist at National Institute for Material Science, Tsukuba, Japan prior to this engagement. Dr. Kalita was a PhD scholar of National Chemical Laboratory, Pune before joining NIMS, Japan. Dr. Nayanmoni Gogoi has recently joined Laboratoire de Chimie de Coordination du CNRS, Toulouse, France as a post doctoral researcher. He completed his Ph.D. thesis entitled “Studies on Discrete Iron Phosphates and Phosphonates, Layered Alkaline Earth Metal Phosphonates and Polyhedral Tin Carboxylates” from

Indian Institute of Technology Bombay, India working under the guidance of Prof. R. Murugavel. Dr. Bipul Sarma will be joining as a Post Doctoral Fellow in the Chemical and Biological Engineering Department, Illinois Institute of Technology, Chicago, USA, under the direction of Prof. Allan Myerson w.e.f. January 2010. He completed his Ph.D. thesis entitled "Structural and Thermal Analysis of Organic Solids" from University of Hyderabad, working under the guidance of Prof. A. Nangia. Dr. Suranjana V. Mayani and Dr. Vishal J. Mayani recently joined the Department of Chemical Engineering, Hoseo University, 165 Sechulri, Baebangmyun, Asan-sity, Choongnam (336-795) Korea as postdoctoral research associates. Dr. Suranjana completed her Ph.D. thesis entitled "Catalytic wet oxidation of phenol and its analogues" from Gauhati University, Guwahati, working under the guidance of Prof. K. G. Bhattacharyya. Dr. Vishal completed his Ph.D. thesis entitles "Chirally modified silicas for separation and asymmetric catalysis" from Central Salt and Marine Chemical Research Institute (CSIR), Bhavnagar, working under the guidance of Dr. S.H.R. Abdi. Mr. Kula Kamal Senapati visited Taiwan in October to participate an international conference on Instrument Technology for Application and Development of Nanobiology and Biosensors at ITRC, Hsinchu Science Park, Taiwan. He has been selected along with other four Indians. Presently, he is working as Scientific Officer at Indian Institute of Technology Guwahati.

5. MEMBERS IN NEWS/FELLOWSHIPS



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Raman Spectrometer Introduction Raman spectroscopy has been recognized as a valuable research technique in the years since the phenomenon was first observed by Dr. C. V. Raman in 1928. However, it is only fairly recently that Raman has emerged as an important analytical tool across the number of industries and applications. No longer designed to appeal only to highly specialized and trained experts, the best of today’s Raman instruments are fully integrated and come with built-in system intelligence that frees the user to focus on results and not on having to become an expert in the technology itself. Due to its sensitivity, high information content, and non-destructive nature, Raman is now used in many applications across the fields of chemistry, biology, geology, pharmacology, forensics, pharmaceuticals, materials science, and failure analysis. Spectral libraries in excess of 16,000 compounds are now available for direct compound identification. In many laboratories, infrared and Raman spectroscopy are used as complementary techniques, because each method looks at different aspects of a given sample. While IR is sensitive to functional groups and to highly polar bonds, Raman is more sensitive to backbone structures and symmetric bonds. Using both techniques provides twice the information about the vibrational structure than can be obtained by using either alone. In addition to providing unique information about a sample, Raman

offers several additional benefits, including:

Minimal or no sample preparation Sampling directly through glass containers Non-destructive analysis, so the same sample can be used in other analyses Non-intrusive analysis, permitting study of more labile sample features, such as crystal structure Minimal water interference No interference from atmospheric CO2 or H2O

Raman Instrumentation & Set-ups The first ever Raman "instrument" was constructed in 1928. This instrument used monochromatized sunlight as a light source and a human eye as a detector. Raman instrumentation was developed (based around arc lamps and photographic plates) and soon became very popular up until the 1950's. Since these early days, Raman instrumentation has evolved markedly. Modern instrumentation typically consists of a laser, Rayleigh filter, a few lenses, a spectrograph and a detector (typically a CCD or ICCD).

The Laser One of the major advantages of dispersive Raman is that it offers the possibility to select the optimal laser excitation wavelength to permit the recording of the best Raman information. For example, wavelengths can be selected to offer the best resonance with the sample under investigation.

6. INSTRUMENT OF THE ISSUE



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Fig. 1: Typical Continuous Wave (CW) Raman layout

One might also need to tune wavelength to avoid fluorescence and thermal emission backgrounds. Nowadays, it is possible to use laser lines from UV, (down to 200nm) up to the infrared, (1.06µm Nd: YAG laser line), from microWatts up to several Watts. Table 1: Comparison of various laser technologies

Detectors Most of the current dispersive Raman set-ups are now equipped with multichannel two-dimensional CCD detectors. The main advantages of these detectors are the high quantum efficiency, the extremely low level of thermal noise (when effectively cooled), low read noise and the large spectral range available. Many CCD chips exist, available in front and back-illuminated formats, but one of the most common spectroscopy sensor formats is the back-illuminated 1024 x

256 pixel array, containing 26 x 26 microns. An excellent compromise in the battle between cost and performance is an open electrode chip. Deep depletion chips have found use recently for improved NIR Raman detection, suitable for use with 785nm lasers. The fact that deep depletion sensors have higher dark current than more conventional sensors, means that it is particularly important to apply effective thermolectric (TE) cooling in these devices. Other chips with smaller pixel sizes, for increasing the spectral resolution, are also available, for example, the Andor iDus DU440A, which uses a sensor: 2048 x 512 pixels of 13.5 x 13.5µm. One must always bear in mind however, the signal to noise implications of dispersing a spectrum over a greater number of smaller pixels. Raman spectroscopists, when using CW lasers, often make us of long exposure times (1 sec to 20 minutes) in order to reach a desired signal to shot noise ratio, and in those instances a multi-MHz readout camera is not required. However, there are many cases where shorter exposure times must be applied, such as when following fast reactions, temperature jump experiments, and also for Raman mapping with high throughput. In



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these instances, the read noise floor of the sensor can contribute significantly to the overall signal to noise ratio. Also, there are many instances in which light levels are fundamentally or necessarily low, such as when studying photolabile molecules, or when the concentration of the probed species is low. Again, this can render the read noise floor more significant. In these cases, the use of the Andor NewtonEM EMCCD platform is recommendable, which offers the choice between conventional readout at slower readout speeds, and single photon sensitivity at either slow or fast readout speeds through an EMCCD amplifier, all with the high QE offered by back-illumination of the sensor. Newton represents the absolute ultimate in spectroscopic detection performance, in terms of sensitivity, speed and also flexibility. It has been shown that CCD quantum efficiency in the red end of the spectrum decreases with cooling, while QE in the blue increases. The flexibility of low temperature TE-cooling systems is one of the reasons why thermo electric cooling is significantly superior to liquid nitrogen cooling.

Fig.2: QE curves relevant to Raman Spectroscopy

Due to the fact that Raman requires a spectrograph, long and thin spectroscopic chips are typically used, (except when using an Echelle

spectrograph). Since Raman is fundamentally a low light phenomenon, dark current is important and so imaging spectrographs and single track mode can be preferred. Using a small single track will also reduce the incidence of cosmic rays.

Spectrographs

Fig. 3: Example of Czerny-Turner layout The most widely used spectrograph configuration for Raman spectroscopy is the Czerny-Turner, such as in the Andor Shamrock 303i or the Shamrock 163i. The Czerny-Turner spectrograph makes use of mirrors as collimators in an off-axis configuration and employs a planar reflective grating in the collimated space, as illustrated on the right. A concave holographic-grating spectrograph can also be used. This is a single element spectrograph. A reflective grating is formed on a curved focusing surface to yield an off-axis spectrograph. The grating is typically a holographic surface relief pattern with a reflective overcoat. Andor Mechelle: The Echelle grating in the Mechelle Spectrograph is a very low-frequency reflective grating. The advantage of this type of spectrometer



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when compared to standard concave holographic or Czerny-Turner designs are as follows:

No moving parts Wide spectral coverage and high

resolution, simultaneously Large reduction in time when

collecting a complete spectrum Compact, rugged design Improved imaging performance

due to refractive optics Efficient coupling with fiber-optic

devices due to fast refractive optics

Rayleigh Filters Rayleigh scatter is elastically scattered light of the same wavelength as the laser and so is of no interest to the Raman spectroscopist. Rayleigh scatter is very intense (typically one million times stronger than Raman scatter) if this light is allowed to pass into the spectrograph, it will be so intense as to render it almost impossible to see any Raman spectrum at all. For this reason Rayleigh scatter must be removed. There are two main techniques for the removal of this light:

Rejection filters: dilectric filters, holographic notch filters & colored glass filters.

Subtractive Double Spectrographs: a double spectrograph functioning in subtractive mode is often used as a Rayleigh filter. This is typically followed by a single dispersive spectrograph. A "triple" spectrograph is very light-hungry and has very poor throughput (~10%). It's advantage is that it is almost infinitely tunable.

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(INVITED ARTICLE)

Two decades of electrochemistry research in the Department of Chemistry, Gauhati University, India Diganta Kumar Das Reader, Department of Chemistry Gauhati University, Guwahati, India [email protected] The department of chemistry Gauhati University was established in the year 1955 and earned the distinction of being the first department for post graduate studies in Chemistry and research in entire north east India. The department attracted international attention when a group of researcher discovered water soluble vitamin A under the guidance of late Prof R K Barua. The research on vitamin A is still going on in the laboratory of Prof B C Goswami in collaboration with Iowa State University, USA. The faculty members since then did not left any stone unturned to keep the status of research in the department at highest possible level. The department now has strong group of researcher in the field of – Environmental pollution and remedies (Prof K G Bhattacharyya and Prof A K Misra), Inorganic synthesis and crystal engineering (Prof B K Das), Organic synthesis and Natural Products (Prof S K Bhattacharyya, Prof P J Das, Dr P Phukan), Catalysis by zeolites and Clay (Prof J N Ganguli and Dr A K Talukdar), Computational Chemistry (Dr C Medhi), Conducting Polymer (Prof D K Kakati) and Supra Molecular Chemistry (Dr R J Sarma). New incumbent S K Gogoi is creating facilities for research on nanotechnology. Prof O K Medhi, now

the vice chancellor of the university initiated electrochemistry research in the department two decades back which is being continued in his and this authors laboratory. As research facility the department now has – UV/Visible spectrophotometers, FTIR spectrophotometers, Atomic absorption spectrophotometer, HPLC, GC-MS, GC, Fluorescence spectrophotometer, Thermal Analyser, Elemental Analyser, Surface Area Analyser, Electrophoresis, 300 MHz H NMR (to be installed) etc. Access to ACS publications through UGC-INFIBNET and Scifinder Scholar facilities are also available. Electrochemistry research facilities in the department: The department owns one BAS 100 B electrochemical work station and one CHI 600 C electrochemical analyzer. The later was purchased under Fast Track scheme of Department of Science and Technology by this author. The spectroelectrochemistry set up and impidence spectroctroscopy are also available in the laboratory of this author. The electrodes the department have includes Glassy Carbon, Platinum, Gold, Silver, Ag-AgCl and Calomel as reference besides Gold and Platinum ultramicroelectrodes. The Farady case with cell stand coupled with nitrogen gas pursing lines and magnetic stirring facilities are also available. Although cyclic voltammetry is mostly used technique, other techniques which are also quite often considered are Square Wave Voltammetry (SWV), Chrono Coulometry and Chrono Amperometry (CA).

7. ARTICLE SECTION



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Electrochemistry of active center analogues of Heme proteins: The research on active center analogues of metalloproteins was initiated by Prof O K Medhi now the vice chancellor of Gauhati University. Protoporphyrin IX iron(III) (PPIXFe(III)) with a suitable pair of axial ligands is an well known active center analogue of heme proteins. PPIX Fe(III) which is otherwise insoluble in water was made soluble by using surfactant micelles and liposomes. Redox potentials were measured using CV and SWV for PPIXFe(III) with the pair of axial ligands as H2O, OH ; THF, H2O and Imidazole, Imidazole1-6.

Surfactant micelles and liposomes provide a hydrophobic and charged environment around the encapsulated PPIXFe(III). Surfactants used to form micelles of different charges are CTAB (positively charged), TX-100 (neutral) and SDS (negatively charged). Significant effect of hydrophobicity and charge on redox potential is observed1-6. The positive surfactant micelles leads to a positive shift in redox potential of Fe(III)/Fe(II) couple while negative surfactant micelles forces a negative shift.

Fig 1: Structure of Protoporphyrin IX Fe(II)

Redox potential of PPIXFe(III) in all the three aqueous surfactant micelles were measured at pH range 2.0 to 12.0. Two proton coupled electron transfer sites were detected with pKa values at 2.5 – 3.5 and 5.5 – 6.5 depending on the charge nature of the micelle4. The pKa at lower value was assigned to the protonation/ deprotonation of H2O ligand on PPIXFe(III). The PPIX macrocycle possesses two propionate side chains remote form the iron as shown in Fig 1. Protonation/deprotonation of these carboxylates effect the redox potential of Fe(III)/Fe(II) couple and results the pKa around 5.5 – 6.5. Micropreoxidase 11 (MP-11) was investigated electrochemically as active center model for cytochrome c. Strong dependence of its redox potential on charge nature of the micellar medium and pH of the medium was reported3. Electrochemistry of active center analogues of Fe-S proteins: The author has successfully completed one UGC research project on detail electrochemistry of a number of active center model of ferredoxins (Fig 2). The model systems considered are – Fe4S4(SC6H5)4, Fe4S4(SCH2CH2COO)4, Fe4S4(SCH2CH2OH)4, and Fe4Se4(SC6H5)4.

Detailed electrochemistry of all the above model systems were carried out in aqueous surfactant micelles, in organic medium in presence of surfactants, in liposomes, in microemulsions and inside film of surfactants7-9. Electrochemistry of ferredoxin active centers inside film and in microemulsions were reported for the first time by the group of this author. Effect of pH on redox potential of all the model systems in all the



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mediums mentioned above were successfully accomplished.

Fig 2: Structure of few active center analogues of ferredoxins.

The principal outcomes of this

research work were – (1) Positive surfactants impart a

positive shift in redox potential of the model system and negative surfactant a negative shift both in aqueous and non-aqueous medium.

(2) When the charge is made static around the model system, that is in the form of film, the influence on redox potential is manifold compared to when the charge is not static that is in solution.

(3) Charge of surfactants also effects diffusion co-efficient by order of 103 times.

(4) Protonation/deprotonation of carboxylates in case of can tune the redox potential by mV.

(5) Microemulsions may be employed as a new medium for electrochemistry.

Development of Voltammetric sensors: Voltammetric sensors have advantages of low cost, easy to handle, no pre-treatment of samples etc. compared to spectroscopic sensors. Working electrode surface has been modified with surfactants, lipids, carbon nanotubes and polymers impregnated with a suitable redox active organic molecules which can interact selectively with the analyte. In the lab of this author voltammetric sensors have been developed, under Fast Track project of DST, for vitamin c, thiourea, caffeine and Zn2+ ion10-15. The sensor for Zn2+ could distinguish it from Na+, Ca2+, K+, Mn2+ and shows very little interaction with Fe2+ and Cu2+. One voltammetric sensor to distinguish urea and thiourea is under development (unpublished work). Table 1 shows the electrode surface modifying agents to target the analyte. One CSIR project has been very recently received to design and develop voltammetric sensor for neurotransmitter dopamine. Table 1: Analyte Working

ElectrodeModifying agent

Vitamin c

GC Catechol in SDS

Thiourea GC Ferrocene in surfactant, lipid

Caffeine GC Vitamin K3 in PVP, lipid

Zn2+ GC Diphenylamine in composite film of SWCNT and CTAB

Conclusion: The department of Chemistry, Gauhati University is playing a pioneering role in the research of applied electrochemistry in the North East India. So far ten people have



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obtained Ph.D. degree for their research in electrochemistry of active center analogue of metalloproteins. Recognition came when the reputed Tata Institute of Fundamental Research, Mumbai has initiated collaboration with the department for doing electrochemistry of metalloproteins. The department will surely one day take a leading role in the country electrochemistry research. Acknowledgement: Financial help received from Department of Science and Technology, University Grants Comission, Council of Scientific and Industrial Research are duly acknowledged. Further reading: 1. D.K. Das, O.K. Medhi

Electrochemistry and spectra of six coordinated high-spin (tetrahydrofurane) protoporphyrinato IX iron encapsulated in aqueous surfactant micelles., Indian J Chem., 37A, 1998, 980-984.

2. D.K. Das, O.K. Medhi The role of heme propionate in controlling the redox potential of heme: Square wave voltammetry of protoporphyrinato IX iron(III) in aqueous surfactant micelles., J Inorganic Biochem., 70, 1998, 83-90.

3. D.K. Das, O.K. Medhi Effect of surfactant and pH on the redox potential of microperoxidase-11 in aqueous micellar solutions., J Chem. Soc. Dalton Trans., 1998, 1693-1698.

4. D.K. Das, C. Bhattaray, O.K. Medhi Electrochemical behaviour of (Protoporphyrinato IX) iron(III) encapsulated in aqueous surfactant micelles., J Chem. Soc. Dalton Trans., 1997, 4713-4717.

5. D.K. Das, O.K. Medhi Aqua

pyridine complex of protoporphyrinato IX iron(III): Effect of ligand binding, surfactant concentration and proton coupling on redox potential, Ind. J Chem. , 44A, 2005, 2228-2232.

6. D K Das, B Das, O K Medhi Electrochemistry of (Protoporphyrinato IX) iron(III) and its Imidazole complexes in Liposomes of L-�-Phosphatidylcholine, J Surface Sc and Technology, 24 (2008) 79-86

7. R C Roy, D K Das, B Das Electrochemistry of [Fe4S4(SCH2CH2CO2)4]6- in liposomes and microemulsions Indian J. Chemistry 47A (2007) 1252-1256.

8. R.C. Roy, D.K. Das, Influence of charged microenvironment on redox potential and diffusion coefficient of [Fe4S4(SPh)4](Nbu4)2 in DMF and inside CTAB film on electrode surface J Chem Sci, 2005, 117, 657-661.

9. R.C. Roy, D.K. Das, Redox linked protonation/deprotonation on the carboxylate of [Fe4S4(SCH2CH2COO-)4]6- in aqueous micellar solutions., Ind. J Chem., 44A, 2005, 1597-1601.

10. D K Das Electrochemical detection of Zn2+ ion using diphenylamine/ carbon nanotube / cetyltrimethylammonium bromide film modified glassy carbon electrode. J Surface Sc. and Technology 24 (2008) 149 - 162.

11. R. Bhattacharjya, D.K. Das Vitamin K3 encapsulated poly(vinylpyrrolidone) film modified glassy carbon electrode for studying the vitamin K3 – caffeine interaction, Indian J Chem, 47A (2008) 394-396.

12. R. Bhattacharjya, D.K. Das, Ferrocene encapsulated lipid and surfactant film on electrode surface. A voltametric sensor for the



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determination of trace amount of thiourea, Indian J Chem 46A (2007) 276-279

13. A Hussain, M Sarma, D K Das Significant effect of egg albumin on the redox potential of vitamin K3 J Ass. Sc. Soc 47(2006)11-14

14. R. Bhattacharjya, D.K. Das Catechol (1,2-dihydroxybenzene) inside charged film on electrode surface. A new voltammetric sensor of vitamin C Ind. J Chem, 45A, , 2006, 909-912

15. R.C. Roy, R. Bhattacharjya, D.K. Das, Effect of film charge on the mid-point potential of encapsulated ferrocene, Ind. J Chem., 43A, 2004, 1689-1691.

About the author:

Dr. Diganta K. Das is presently working as Reader in the Department of Chemistry, Gauhati University, Guwahati. He obtained his Ph.D. from Gauhati University. His research interests are bioinorganic chemistry, electrochemistry, and development of voltammetric sensors. He can be reached at: [email protected]

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An insight on Hybrid nanocrystals

Sasanka Deka

Nanochemistry Division, Italian Institute of Technology, Via Morego 30, 16163 Genova, Italy Email: [email protected], [email protected]

Colloidal hybrid nanocrystals

(HNC) are new class of materials or represent last-generation breeds, where different inorganic sections are joined together through a common interfacial area and sharing of the common contact junctions by the constituent domains. This leads to diverge the physico-chemical properties of the individual components. Such multimaterial nanocrystal heterostructures contains two or more materials of same or different functionalities, such as photoluminescence, magnetism, or catalytic activity, etc. They are attractive candidates for enabling the bottom-up fabrication of unique materials and target advanced applications in several technological fields concurrently. In the present article I will discuss the basics of heterostructure/hybrid nanocrystals based on only inorganic materials, their exciting synthesis strategiesy. Moreover, we will stick to nanoheterostructures only since the nanoscience and technology become too broad and popular and the scope this article is too limited to define all the terms of nanomaterials.

We can have two types of

inorganic heterostructures. One strategy for binding together two different materials is to grow one material on top of the other in an epitaxial fashion. In this assumption, one can consider the core-shell nanoparticles as the simplest example

IN PRAISE OF SCIENCE

Science is not formal logic–it needs the free play of the mind in as great a degree as any other creative art. It is true that this is a gift which can hardly be taught, but its growth can be encouraged in those who already posses it. Max Born (1882-1970) German Physicist. Nobel Prize, 1954.



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of such heterostructures. In the so-called core/shell NCs, for instance, an additional inorganic material is uniformly grown around a nanocrystal core, for special purposes. A more elaborate shape can be achieved when a second material is grown only on specific regions of a starting nanocrystal. This process can be triggered by the different reactivities of the individual facets of this starting nanocrystal. To explain such heterostructure, at first we can take the example of semiconductor-semiconductor core@shell heterostructure. The different possibility of combination of semiconductor materials to form a nanoheterostructure is shown in Figure 1. For instance Figure 1a and 1b shows the formation of spherical core@shell and double shell heterostructures, respectively. Again semiconductor nanorods can be overgrown by another material of different band gap as shown in Figure 1c and 1d. Here generally the surface of a semiconductor nanocrystal is covered by another semiconductor material in the form of a shell either having a larger band gap than the core material or relatively different band alignment. These types of core/shell heterostructures are useful for many biological applications. Different band alignments of semiconductors are shown in Figure 2, taking into account the example of CdSe, CdS, ZnS and CdTe. If the band gap of the core material is smaller than the shell semiconductor, then it is called Type-I heterostructure. This type of band gap alignment leads to a confinement of the charge carriers in one compartment of the heterostructure. Thus we can achieve a chemically stable system and high photoluminescence. CdSe@CdS, CdSe@ZnS and CdS@ZnS core/shell heterostructures are example of Type-I system. In these examples, CdSe is the

core material in CdSe@CdS and CdSe@ZnS and CdS is the core semiconductor in CdS@ZnS system. From Figure 2 we can see that CdS and ZnS has a larger band gap than that of CdSe, again ZnS has a larger band gap than that of CdS. To explain the other type of core/shell system, we can consider the example of CdSe@CdTe. In this system, both, CdSe and CdTe has almost equivalent gap. But their band alignment is different, when they form core/shell heterostructure. In the present case either CdSe or CdTe might be the core. This type of heterostructure is called Type-II system.

Figure 1. Semiconductor-semiconductor core@shell heterostructures. (a) spherical core@shell, (b) spherical core@shell@shell or double shell, (c) asymmetric core@shell nanorods and (d) asymmetric core@shell@shell or double shell nanorods where a 0-D sphere is present as the inner-core.

Figure 2. Bulk values of the band-edge positions and band alignment of CdSe/CdS, CdSe/CdTe and CdSe/ZnS core/shell heterostructure.

In the same way as the growth

rate of some facets of a nanocrystal can be made extremely slow, also the nucleation of a second material can be



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suppressed on them. In this case a so-called “anisotropic hybrid nanocrystal” will be grown. In synthesizing various hybrid nanocrystals (both core/shell and anisotropic), the first key requirement is to prevent separate homogeneous nucleation of the second inorganic material. To promote heterogeneous nucleation of the second material on the surfaces of the first material, the surface capping molecules should not be bound strongly such that they interfere with the hetero-interface formation and the interfacial chemistry of the two materials must be compatible. Category of hybrid nanostructures, metal-semiconductor, metal oxide-semiconductor, metal-metal heterostructure systems are interesting from the view point of basic understanding of the hetero-junction or the hetero-interface and for practical applications. To understand this in a better way, readers can refer to Figure 3. Few of the reaction schemes used to synthesize nanoheterostructures consisting metal-semiconductor-oxides are explained pictorially.

Magnetite nanocrystal domains

on gold nanodomains can be grown by a thermal-decomposition reaction followed by oxidation reaction as shown in Figure 3a. Same type of thermal decomposition reaction of Co2(CO)8 has been carried out in Figure 3g to decorate CdSe@CdS core/shell nanorods with Co metal domains. In this type of hybrid nanocrystals, Co spheres are deposited at specific sites (tip) of the CdSe@CdS nanorods. FePt nanocrystals are introduced to Cd-acetylacetonate and elemental sulfur environment to manipulate the synthesis of FePt@CdS core/shell or FePt-CdS heterostructure nanocrystals (see Figure 3b). The temperature of the reaction is the main controlling factor for the formation of

different kind of products. Other examples of magnetic oxide-semiconductor hybrid nanocrystals are seen in Figure 3c and 3f. Here either the iron oxides or the semiconductors (CdSe or CdS) domains are grown at some specific sites of the other one. The growth of the second material (as well size and shape) could be well controlled by the concentration of the precursor materials, amount of solvent and time and temperature of the reaction. Figure 3d and 3e also show some peculiar type of nanoheterostructures forming core/shell or Pt/ZnO hollow and porous nanocage.

Figure 3. Different reaction schemes (a-g) are available in the literature to prepare hybrid nanocrystals of different functionality. Further explanation and ref. of each scheme is available in Ref 1.

In conclusion, hybrid

nanocrystals are important class of materials from the view point of basic research of complex materials and engineering of nanomaterials.



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Although several methods are available in the literature to synthesize such kind of heterostructurs, still plenty of rooms are there to make new combinations. If a new combination gives rise to a new functionality and adorability with cheap manufacturing cost, then definitely that heterostructure will be acceptable for further applications. Further reading: 1. “Hybrid Nanocrystals: Synthesis,

Characterization, Optical and Magnetic properties” S. Deka, A. Figuerola, D. Dorfs, L. Manna. Book chapter in Encyclopedia of Semiconductor Nanotechnology. Ed. Ahmad Umar, American Scientific publishers, California, to be published in 2009-2010.

2. D. J. Milliron, S. M. Hughes, Y. Cui, L. Manna, J. B. Li, L. W. Wang and A. P. Alivisatos, Nature 430, 190 (2004).

3. P. D. Cozzoli, T. Pellegrino and L. Manna, Chem. Soc. Rev. 35, 1195 (2006).

4. M. A. Hines and P. Guyot-Sionnest, J. Phys. Chem. 100, 468 (1996).

5. S. Deka, A. Quarta, M. G. Lupo, A. Falqui, S. Boninelli, G. Lanzani, G. Morello, M. De Giorgi, C. Giannini, R. Cingolani, T. Pellegrino and L. Manna, J. Am. Chem. Soc. 131, 2948 (2009).

6. Quarta, A. Ragusa, S. Deka, C. Tortiglione, A. Tino. R. Cingolani and T. Pellegrino, Langmuir, in press (doi/abs/10.1021/la901831y)

7. S. Deka, A. Falqui, G. Bertoni, C. Sangregorio, G. Poneti, G. Morello, M. D. Giorgi, C. Giannini, R. Cingolani, L. Manna and P. D. Cozzoli, J. Am. Chem. Soc. 131, 12817 (2009).

About the author:

Dr. Sasanka Deka presently a senior researcher at Italian Institute of Technology, Genova, Italy. He obtained his Ph.D. from the University of Pune after carried out his research work on materials chemistry at National Chemical Laboratory, Pune, India. His interest and area of research works are nanotechnology, multifunctional materials, hybrid nanocrystals for optical, photonics, electrical and biological applications, metal oxides for fuel cell gas reforming catalyst and novel nanocrystals for hybrid photovoltaic cells.

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From DNA to proteins, one of the life`s core processes (http://nobelprize.org)



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In-Vitro and Cryopreservation Techniques for Conservation of Microbial Resources Debajit Thakur Biotechnology Department, Plant Improvement Division Tocklai Experimental Station, TRA, Jorhat-8, Assam 1. Introduction:

Biodiversity may be precisely defined as the co-existence of various flora and fauna in a particular ecological niche. India has a rich and varied heritage of biodiversity, encompassing a wide spectrum of habitats from tropical rainforests to alpine vegetation and from temperate forests to coastal wetlands. India figured with two hotspots - the Western Ghats and the Eastern Himalayas - in an identification of 18 biodiversity hotspots carried out in the eighties (Myers. 1988). In 2000, Norman Myers and a team of scientists have brought out an updated list of 25 hotspots (Myers et. al. 2000). In the revised classification, the 2 hotspots that extend into India are The Western Ghats/Sri Lanka and the Indo-Burma region (covering the Eastern Himalayas); and they are included amongst the top eight most important hotspots. In addition, India has 26 recognized endemic centers that are home to nearly a third of all the flowering plants identified and described to date.

Generally when we talk about bio-diversity, it is quit obvious to discuss about visible components of the ecosystem only. This may include the rare, endemic and exotic plant and animal species. Undoubtedly those exotic, endemic flora and fauna contributes to the richness of bio-diversity and natural beauty in a particular geographical area. But in addition to that we have another

potential sector in bio-diversity which encompasses the entire microbial flora of the globe and that gold-mine area is the microbial diversity. Microbial diversity, being an integral part of biodiversity includes bacteria, fungi, actinomycetes, microalgae, protozoans and other monerans. A total of 16,04,000 species of Monera, Protista, Fungi, Plantae and Animalia have been described globally (Whittfield, 2002) however it is likely to be 17,980,000 species i.e. about 11 times more than the presently known species. Of these, India has over 126,188 species of bacteria, fungi, plant and animals with nearly 72% of India’s biowealth constituted by fungi (18.23%), insects (40%) and angiosperms (13.50%) (Khoshoo, 1995). India is rich in its biodiversity resource and there are about 850 (0.67%) moneran species, 2577 (2.04%) Protistan species, 23,000 (18.23%) fungal species, 2500 (2%) species of algae, 74,875 (59.27%) animal species and 24,886 (17.79%) different plant species in India (Khoshoo, 1995). Watve et al. (1999), observed a possible estimate of several fold higher myxobacterial diversity in India than the species recorded worldwide so far.

To save microorganisms is different from animals and plants, because microorganisms are not typically classed as plants or animals, which include bacteria, cyanobacteria, fungi, protozoa and virus, but they are important to humans for the benefits and harmful effects. Microorganisms are also the essential parts of environment, contributing to the maintenance of stable ecosystems because they are found in nearly all environments. Unfortunately, conserving the microbial diversity was not concerned as that for the animals and plants. However, existing conservation programs for animals and plants diversity, such as the nature



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reserves, will likely cover all but a few specialized environments, so it should not establish special reserves for maintaining microbial diversity. However, we also need to preserve microorganisms off site. The techniques to maintain microbial (virus, bacteria, fungus) diversity include: (i)Isolating and sampling: These methods are used to obtain pure strain microorganisms for special needs and keep them in a suitable medium, which contains the nutrition, as the microorganisms need. (ii)Microbial identification: The procedure of the identification involves staining standard and microscopic examination, and also includes biochemical analysis of proteins and DNA.

(iii)Storage of microorganisms. To preserve microorganisms is to maintain a strain for an indefinite period or continuous culture.

It is important that microorganism resources are preserved in a physiologically and genetically stable state. Therefore, frequent subculturing on a slant is not recommended. Subculturing may also lead to contamination. A variety of methods are available for strain preservation, which keep their vitality and authenticity. The major methods that give stable preservation are freeze-drying, L-drying (drying from the liquid state), cryopreservation (in the vapor phase of liquid nitrogen or in a deep freezer) and subculture under mineral oil (Mikata 2002; Smith and Onions 1994). The methods used for preservation depend on the microbial species. Freeze-drying is suitable for preservation of bacteria, Actinomycetes, yeasts, and spores of fungi. Cryopreservation is applicable

to most microorganisms. In these techniques, cryoprotectants and growth conditions are also important for successful preservation. The conservation results could be affected by lots of factors during the preliminary culture preparation, by the choice of protectants, preservation and regeneration methods with minimum consequences for the strains. With the development of microbiology the requirements for the culture preservation increase. It is not enough to perform a successful conservation; it is also necessary to keep the strain for a long–term period.

1.1. Some Microbial culture collections in India • Biodiversity Documentation Centre,

Jawaharlal Nehru – • Centre for Advanced Scientific

Research, Jakkur, Bangalore • Centre for Cellular and Molecular

Biology, Hyderabad – • College of Agriculture, Maharana

Pratap Agricultural University, Udaipur

• Defence Material and Stores Research and Development Establishment Culture Collection

• Defence Research and Development Organization, New Delhi

• Delhi University Mycological Herbarium

• Department of Microbiology, Bose Institute

• Division of Standardization, Indian Veterinary Research Institute, Izatnagar, Bareilley, UP

• Fungal Culture Collection, University of Delhi, New Delhi 70 strains of fungi

• Indian Institute of Science, Bangalore http://www.iisc.ernet.in

• Indian Type Culture Collection



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• Division of Mycology and Plant Pathology, Indian Agricultural Research Institute, New Delhi, www. iaripusa.org

• MACS Collection of Microorganisms

• Marathwada Agricultural University (Collection of insect pathogens), Parbhani

• Microbial Type Culture Collection and Gene Bank (MTCC) 3020 cultures of fungi,

• Institute of Microbial Technology, Chandigarh, www.imtech.res.in

• National Bureau of Agriculturally Important Microorganisms (NBAIM), Kusmaur

• National Collection of Dairy Cultures, National Dairy Research Institute, Karnal, http://www.ndri.nic.in

• National Collection of Industrial Microorganisms National Chemical Laboratory, Pune, http://www.ncl-india.org/ncim

• University of Mumbai, Food and Food Technology, Mumbai.

2. Methods for maintenance and preservation of microbial strains:

Microorganisms require special preservation methods in order to ensure optimal long-term viability and genetic stability. In general each preservation method can be assigned to one of the following groups: a) Metabolically active methods

Periodic transfer on agar or in liquid medium Keeping agar cultures under mineral oil

b) Metabolically inactive preservation techniques

Cryopreservation Freezing and low temperature storage in or above liquid nitrogen Freezing and low temperature storage below -70°C

Drying Preservation by shelf freeze-drying Preservation by spin freeze-drying Preservation by liquid drying (L-drying) Preservation by vacuum drying Maintenance of strains by

metabolically active methods should be used only in case a strain cannot be preserved by one of the metabolically inactive methods, or in addition to one of these methods. Strain preservation methods can be described as follows: 2.1. Subcultivation:

The subcultivation is a method of periodical cultivation on agar nutrient medium and it is the oldest method used for microorganisms maintenance and preservation in laboratory and industrial conditions. A main principle in the cultivation is taking cell material from great amount of colonies. Using a single colony is not recommended because this increases the unwanted selection probability. Thus the control of the innate strain characteristics, activity change and vitality could be impossible (Donev, 2001).

The choice of nutrient medium

for strain cultivation is essential for the method application. Choosing correct nutrient compounds is the base of further preservation of taxonomical, morphological and biochemical culture properties. The regularity of the cultivation is different for the separate microorganisms groups and varies from 30 days to several years, at preservation temperature 3-5°C. According to some scientists the temperature increasing over 5°C leads to quick lost of cell viability (Ruban, 1989). The average conservation longevity for yeasts is 1 to 3 months.



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Data exist that some bacteria are conserved for 5 to 12 months and microscopic fungi over 5 years. Fungi are the longest preserved by subcultivation strains and have been kept since 1895 (Novik et al., 1998; Valagurova et al., 2000). Figure shows a part of Streptomyces cultures producing bioactive metabolite maintained in slants at TRA, Jorhat 2.2. Mineral oils:

Other cultures preservation method is under mineral oil. It was applied for the first time in 1914 by A. Limier to keep the gonorrhea agent (Neisseria gonorrhoeae). In 1921 by this way M. Michelle preserved in broth gonococci, meningococci and pneumococci (Krasilnikov, 1967). The method essence is covering the well grown culture on liquid or agar nutrient medium with sterile non-toxic mineral oil. The most common used oil is paraffin or vaseline with layer thickness 1 to 2 cm. The aim is to limit the oxygen access that reduces the microorganisms’ metabolism and growth, as well as to restrict the cell drying during preservation in freezing conditions. According to some investigations the microorganisms conservation period under Vaseline oil without subcultivation is 1 to 12 years depending on their properties. Optimal and utmost time limits are established for cultivation of different taxonomical groups. Different genera yeasts are studied and it is determined that the conservation period varied from 1 to 7

years (Arkadieva and Pimenova, 1985; Kupletskaya and Arkadieva, 1997). 2.3. Water or water–salt solutions:

There are data for microbiological objects preserving in water or water–salt solutions. The cells are placed in indifferent liquid medium and they approach a hypobiotic state. The suspension density, the presence of Ca2+ ions in the medium, the solution composition and pH, the preservation temperature influences the quantity and protection of the cells at rest. For example, it is determined that direct cause for the accelerated death of Escherichia coli with population number over 109 cells/ml is the accumulation of lethal metabolites in the intercellular medium. Their concentration grows with the cell density increasing. The optimal pH for 1 month preservation of E. coli is pH 8 and for S. cerevisiae - pH 5.5. This method is recommended for short term storage at 4-8 °C for 1 week to 12 months (Claudia et al., 2002; Vachitov and Petrov, 1992). 2.4. Drying:

The cultures conservation method that imitates the natural conditions is drying preservation. It is based on the natural microorganism properties to fall into anabiosis. Sand, soil, mud, active carbon, saw-dust, synthetic balls and tablets, polymer matrixes, high disperse materials, filter paper etc are used as microbic material carrier. The large carrier surface adsorbs part of the moisture. The drying is performed at room temperature or by heating up at 36-40°C. In 1966 Coe and Clark applied the method for strains Staphylococcus aureus, announcing preservation date 6 months (Norris and Ribbons, 1970).

There are references for stability investigations after conservation on different carriers and



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following drying of representatives of the genera Shigella, Salmonella, Proteus, Bacillus, Streptococcus, Pseudomonas, Corynebacterium, Rhodococcus, Serratia, Mycobacterium, with advisable conservation time to 12 month at temperature 4 °C (Bilko, 1988; Champagne and Gardner, 2001). In 1954 Anner for the first time used vacuum to speed up the process of microbial suspension drying. The method is named “L-drying”. It is used for the conservation of spyrochetas, leptospyras, salmonellas and some yeast and virus strains (Norris and Ribbons, 1970). 2.5. Cryogenic conservation:

In the last decades of twentieth century the cryogenic conservation was characterized with quick accumulation of significant results from fundamental investigations in microbiological science. It is well known that the laboratory microorganisms could not always be lead to anabiosis by cooling and freezing. Often the cells die or remain alive but not viable. The temperature decrease affects the biological systems and series of mechanical, physiological and biochemical changes occur. Depending on the cooling and overcooling level, the cells suffer different damage consequences by the “temperature shock” ( Feofilova, 2003).

During the cryogenic treatment of the cells a great number of damage factors are known (Safonova et al., 1991). The literature gives theoretical and experimental data referred to the influence of the freezing and thawing rate upon the form of the crystals and their destructive action to the cell (Donev, 2001; Novik, 1998).

The thawing of different microorganisms is usually in water bath at temperature 25-41°C. The slower static thawing of the cells

(stored at low temperatures of minus 135°-196°C) at room temperature could lead to lethal recrystallization in the temperature range between -130 to -110°C (Ivanov and Puchkov, 1989; Tsutsayeva, 1987).

2.6. Freezing in liquid nitrogen:

The method of freezing to -196°C and preservation in liquid nitrogen or its vapor is basic for most of the culture collections. Actinomycetes, bacteria, yeasts, fungi, plant and animal viruses and cell cultures are conserved that way. According to some scientists the optimal cooling rate for fungi is 1°C.min-1, for yeasts 7-10 °C.min-1, for bacteria and actinomycetes 2-45°C.min-1 (Sidyakina, 1988). 2.7. Lyophilization:

Lyophilization, vacuum – sublimation drying or freeze-drying are the commonly accepted names for the process of taking away the entire quantity freeze moisture from the solid matrix of the wet containing materials by vacuum sublimation. The lyophilization consists of the following stages: • material freezing to low temperatures – below the eutectic temperature; • primary drying when the ice crystals sublimate influenced by the passed in the system heat energy in vacuum conditions; • secondary drying when after the ice separation the remained material moisture is desorbed in maximum deep vacuum conditions (Pushkar et al., 1984). There are a great number of literature data for the microbiological cultures lyophilization (Arkadieva et al., 1975; Kupletskaya, 1987; Urakov, 1988). From all microorganisms groups the bacteria sustain lyophilization the best (Mehandjiska et al., 1989).



41

3. Protectants Protective compounds- cryoprotectants, are found to eliminate most of the multiple destructive factors during freezing of biological structures. According to the location of their action the cryoprotectants are divided in two groups: • endocellular cryoprotectants – media, penetrating cells; • extracellular cryoprotectants – media, connecting with the extracellular water. Endocellular protectants: The application of protective media with endocellular mechanism presents a cell penetration. The media overcooling before the freezing contribute to small crystal formation, which restricts the mechanical disturbing action during the cryogenic treatment. The main endocellular protective media are glycerol (glycerin, 1, 2, 3 propantriol, C3H8O3) and dimethylsulphoxid (DMSO, C2H6SO). Extracellular protectants: Some of the extracellular protectants applied to preservation of the biological objects in frozen state are polyvinylpyrrolidone, hydroxyethyl starch and dextran.

4. Quality control after preservation:

After preservation of a microbial strain controls are necessary. At least viability and purity, and where appropriate, the identity of the preserved culture have to be checked immediately after preservation. A registration form for the freeze-drying process per batch (e.g. vacuum, product temperature, shelf temperature, condenser temperature, time) should be filed. Any remark on the viability or properties of a batch has to be archived and remain available to compare with future controls.

5. Example of data sheet to create industrially important microbial database: Name of the Microorganisms : Collection Details: Biochemical Tests:

Collection No: Urea Hydrolysis:

Collected By: Catalase Test:

Date of collection: Citrate Utilization Test:

Season (Weather): Methyl Red Test:

Locality: Gelatin Liquification Test:

Site : Nitrate Reduction Test:

District: Starch Hydrolysis Test:

State : Test for Indole Production:

Altitude: H2S Production Ability:

Habitat: Ammonia Reduction Test:

Soil (type, pH): Endospore Formation:

Substrate: Special Characteristics:

Temperature:

Morphology: 16S rRNA sequence data: Similarity with other organisms (With the help of Blast) 6. Conclusion:

For all biological materials preservation, cryopreservation and freeze-drying are the preferred techniques for long-term storage. The potential of storing lives is extended to many thousands of organelle, cell, tissue, organ, and body types including microorganisms, plants and animals. More recently, cryopreservation has been used as an appropriate technique to preserve plants and animal species. However, many cells and tissues, which need for long-term bio-storage await suitable methodologies. As different biologies of organisms make different responses to cryoprotectants



42

and freezing, preservation protocol may need adjustments, or be constructed afresh for the materials under study. Freeze drying is widely employed to conserve micro-biodiversity. This is one of the key roles performed by microbial culture collections. However, there is no unique method to store all biological material.

The support of culture collections is an essential element of the microbiological science, practice and their development. The man has accomplished to choose and select thousands of useful microorganisms, which now are the base of the biotechnological processes. Some of them are strains involved in the production of dairy, bakery, spirits, alcohol, vaccines, antibiotics, enzymes, silage, vinegar etc. Parallel with the process of isolation, selection and genetic engineering a need arises for the preservation of strains, their vitality, specificity, activity, immunogenicity and other properties in laboratory conditions. The production standard and quality depend on the right choice of preservation methods of the industrial strains. Further reading: 1. Arkadieva, Z. A., Pimenova M. N.,

1985. Appl. Biochem. Microbiol. 21 (5), 645-648.

2. Bilko, I. P., 1988. J. Microbiol. 50 (1), 96-97.

3. Champagne, C. P. and Gardner N. J., 2001. Elect. J. Biotechnol. 4 (3), 146-152.

4. Claudia, C., L. Lastra, Hajek A. E., Humber R. A., 2002. Can. J. Bot. 80 (10), 1126-1130.

5. Donev, T. N., 2001. Methods for conservation of industrial microorganisms, Sofia: NBIMCC, 93.

6. Donev, T. N., 2001. Methods for conservation of industrial microorganisms, Sofia: NBIMCC, 93.

7. Feofilova, Е. P., 2003. Appl. Biochem. Microbiol. 39 (1), 5-24.

8. Ivanov, S. A. and Puchkov Е. О., 1989. Microbiology. 58, 699-701.

9. Khoshoo TN 1995 Census of India’s biodiversity: Tasks ahead . Curr Sci,69(1): 14-17.

10. Krasilnikov, N. A., 1967. Preservation methods for culture collection microorganisms, Moskva: Nauka, 151 (in Russian).

11. Kupletskaya, М. B. and Arkadieva Z. А., 1997. Microbiology. 66 (2), 283–288.

12. Mayer, N., Mittermeier, R. A., Mittermeier, C. G., Fonseca, G. A. B. and Kent J. 2000. Biodiversity hotspots for conservation priorities. Nature. 403: 853-858.

13. Mikata, K. (2002) Studies of long-term preservation of yeast cultures. Microbiol. Cult. Coll., 18, 3–16.

14. Myers, N. 1988 Threatened biotas: 'hotspots' in tropical forests Environmentalist 8: 187-208.

15. Norris, J. R. and Ribbons D. W., 1970. Methods in microbiology, London, New York: Acad. Press, 319.

16. Novik, G. I., Astapovich N. I., Kadrinkova N. G., Ryabaya N. Е., 1998. Microbiology. 67 (5), 637-642.

17. Ruban, Е. L., 1989. Appl. Biochem. Microbiol. 25, 291-301.

18. Safonova, V. I., Novikova N. I., Sidyakina Т. М., Bozjeva L. Т., 1991. Microbiology. 60 (2), 368- 376.

19. Sidyakina, Т. M., 1988. Methods for conservation of microorganisms. Ser. Conservation of genetic resources, Pushchino: AS USSR, 59.

20. Smith, D. & Onions, A. H. S. (1994) The preservation and



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maintenance of living fungi, 2nd ed., CAB International, Oxfordshire, pp.122.

21. Tsutsayeva, А. А. (Ed.), 1987. Cryobiology and biotechnology, Kiev: Naukova Dumka, 216.

22. Vachitov, Т. Y. and Petrov L. N., 1992. Microbiology. 61 (6), 1087-1095.

23. Valagurova, Е. V., Kozairitskaya V. Е., Pindrus А. А., Azimtseva О. А., 2000. J. Microbiol. 62 (4), 3-8.

24. Watve MG, Shete AM, Jadhav N, Wagh SP, Sheetal PS, Chakraborti SS, Botre AP & Kulkarni AA 1999 Myxobacterial diversity of Indian soils-How many species do we have ? Curr Sci, 77(8): 1089-1093.

25. Whittfield J 2002 Neutrality versus the niche. Nature (News feature), 417: 480-481.

About the author:

Dr. Debajit Thakur received his Master of Science degree in Botany (specialization in microbiology) from Gauhati University, Assam, in 1999 and his doctorate in Life Sciences in 2004 from Dibrugarh University, Assam. Dr. Thakur has joined as research fellow in the Department of Biotechnology at North East Institute of Science & Technology (CSIR, Govt. of India), Assam, India, in 1999, where he worked on microbial diversity, exploration of microbial bioactive molecules, biotransformation of β-lactam antibiotics, and biocontrol of plant pathogens. He has received National Merit Scholarship during

M.Sc., Lady Tata Memorial Junior Fellowship under 2000-2002 programme from LTMT, Mumbai, Senior Research Fellowship from CSIR (Govt. of India), in 2002. He worked postdoctoral research at Institute of Microbial technology (CSIR, Govt. of India), Chandigarh, India. He has also received fellowship from Department of Science & Technology, Govt. of India, under the Scientific and Engineering Research Fast Track Scheme for Young Scientists (FAST) in 2006. He has published his research findings in eminent publishers like Elsevier, Springer, Willey etc. and published five book chapters. At present Dr. Thakur is working as a Biotechnologist, at Department of Biotechnology, Tocklai Experimental Station, TRA, Assam, India. He can be reached at [email protected].

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WHAT IS SCIENCE?

Science is organized knowledge. Herbert Spencer (1820-1903) English philosopher. Education.

Science is the systematic classification of experience.

George Henry Lewes (1817-78) English writer and critic.

Science is simply common sense at its best that is, rigidly accurate in observation, and merciless to fallacy in logic.

Thomas Henry Huxley (1825-95) English biologist.

Science is nothing but trained and organized common sense differing from the latter only as a veteran may differ from a raw recruit: and its methods differ from those of common sense only as far as the guardsman's



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cut and thrust differ from the manner in which a savage wields his club.

Thomas Henry Huxley (1825-95) English biologist. "The Method of Zadig" in Collected Essays IV.

Science is nothing but developed perception, interpreted intent, common sense rounded out and minutely articulated.

George Santayana (1863-1952) U. S. philosopher and writer. The Life of Reason.

Science is facts; just as houses are made of stone, so is science made of facts; but a pile of stones is not a house, and a collection of facts is not necessarily science.

Jules Henri Poincaré (1854-1912) French mathematician.

Science is the great antidote to the poison of enthusiasm and superstition.

Adam Smith (1723-90) Scottish economist. The Wealth of Nations, 1776.

Science is what you know. Philosophy is what you don't know.

Bertrand Russell (1872-1970) English philosopher, mathematician.

It requires a very unusual mind to undertake the analysis of the obvious.

Alfred North Whitehead (1861-1947) English philosopher and mathematician.

[Science is] the labor and handicraft of the mind.

Francis Bacon (1561-1626) English essayist, philosopher, statesman.

[Science is] the literature of truth.

Josh Billings (Henry Wheeler Shaw) (1818-85) U. S. humorist.

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Cancer Drug Delivery and Challenges Manashjit Gogoi Indian Institute of Technology, Bombay Cancer represents perhaps two hundred diseases that cause abnormal and uncontrolled growth of malignant cells. Cancerous cells are highly unorganized and irregular in shape and size. The internal structures of cancerous cells are inconsistent and misshapen. It is a life threatening disease that has been affecting mankind since ancient times. Bone cancer has been discovered in the mummies of Egyptian and Peruvian civilizations. Symptoms of cancer and primitive ways of treatment were documented in papyruses of different ages such as Edwin papyrus (2500BC), Leyde papyrus (1500BC), and Ebers (1500BC) etc. Hindu epic the Ramayana (500BC) too describes the use of arsenic paste for cancer treatment. Around 400BC, the term “carcinoma” was coined to represent cancer by Hippocrates- father of medicine. Carcinoma comes from Greek “Karkinoma” meaning “Crab”[1] The exact causes and the ways of initiation and spreading of cancer are still not well understood, but both external factors (e.g. tobacco smoking, infections, exposure to retroviruses, chemicals and radiations) as well as internal factors (e.g. inherited metabolism mutations, hormones and immune conditions) are believed to be the reasons for cancer formation and growth. These factors may act together or in sequential manners to initiate and promote cancer. Till date, no complete curing procedure for cancer is available, only remission or palliation is possible with the current treatment procedures. A cancer is said to be in



45

remission state when all clinical evidence of cancer has been disappeared and the microscopic foci of cancer cells may still remain. Effective treatment modalities include surgery, radiotherapy, chemotherapy, hormone therapy, immunotherapy and hyperthermia. Each of these modalities has their own advantages as well as disadvantages and usually combination of two or more modalities give the best result. Early detection, regular screening, examinations and then application combination therapy play an important role in cancer prevention and treatment. It is evident that the risk of developing cancer can be reduced by controlling tobacco and alcohol, obesity and sun exposure, having healthy diet and physical activity. Routine cancer screening is also a necessary to prevent cancer [2,3]. Chemotherapy is the treatment procedure of any disease using a specific drug. Chemotherapy for cancer is used in a narrower sense of treating cancer with the aim to kill or control cancerous cells. The chemotherapeutic drug is highly toxic or even life threatening. More toxic drugs are more effective. They kill both malignant and normal cells. So, due to the application of chemotherapeutic drug (s), patients have to tolerate lot of side effects and the qualities of the life deteriorate. Chemotherapeutic agents reduce the white blood count, red blood count and platelet count of the patient that means the immune system of the patient is being suppressed. Therefore it makes the patients more susceptible to other infections. In addition to these, patients loss hair, experience nausea, vomiting, pain and suffer from diarrhea, constipation etc. Sexual and reproductive power is also affected by chemotherapy. Due to these colossus amount of side effects the effective

dose of anticancer drug could not administered to the patient(s). So, treatments become futile. One more problem associated with the chemotherapeutic drug is that the tumor cells become resistant to multiple drugs i.e. development of multiple drug resistance (MDR) cells. Exposure to drug results in over expression of certain proteins like P-glycoprotein (P-gp), Multidrug Resistance-associated Protein (MRP), Lung Resistance related Protein (LRP) etc. in tumour cells. These P-gp and MRP are expressed in cell membrane and they pump out the drug from the cancer cells and hence responsible for substantial reduction of effect of drug. LRPs are present in cytoplasm of cell. There exist few other groups of proteins which are responsible for development of MDR cells by altering the drug target through gene mutation. Therefore, people are looking for more advanced drug delivery systems [2, 4].

Nano-carrier Drug Tumour cell Endothelial Cell

Figure: EPR effect where nano-carriers reaches the tumour cell through the pores of poorly organized endothelial cells

With the advancement of science and technology, nanoparticles are emerging as effective drug delivery systems for treating cancer. Nanoparticles like liposomes, solid lipid nanoparticles, dendrimer, nanocapsule, magnetic nanoparticles, nanoparticles made of different biocompatible and biodegradable polymer have been explored for tumor targeted drug delivery. The basic requirements of these nanoparticles are (i) ability to



46

sustain in blood for long time, (ii) sufficient tumor accumulation and (iii) controlled drug release. It is well established that nanoparticles are often engulfed and cleared by reticuloendothelial system (RES). RES is a part of our immune system (body’s defence system) and it clears the foreign materials from our body. The nanoparticles could be made to escape from RES system and long circulating in the blood by modulating the size, surface size and composition. Often these nanoparticles are coated with polyethylene glycol (PEG) to make long circulating. PEGylation of nanoparticles inhibits the adsorption of protein on the nanoparticles surface makes them stealth nanoparticles and hence protects it from being opsonized. The microvasculature of tumor tissue is not uniform and the lymphatic drainage system that removed the body’s waste is also not well organized. As shown in figure, the portion of the blood vessels that supplies nutrients to the tumor becomes leaky and unorganized. Normal drug present the blood can reach different parts of the body even through the well organized endothelial cells, but nanoparticles cannot go through the well organized endothelial cell due to their size. But it can reach the tumor sites through leaky vasculature and get accumulated there because of the poor lymphatic drainage system. This process is called Enhanced Permeability and Retention (EPR) effect. It is passive targeting of the cancer cells. The other way of targeted drug delivery is active targeting. Cancer cells over express some of proteins or receptors e.g. folic acid is required to cell proliferation. Due to higher proliferation rate cancers cell need folic acid and folic acid receptor are being over expressed on the surface of tumor cells. So, folic

acid tagged nanoparticles can be used for active targeting of this kind of cancer cells. Similarly, anti-HER2 (Human Epidermal growth factor Receptor 2) antibody can be conjugated to target some of the breast cancer cells having higher expression of HER-2. There exists a host of proteins/ receptors in different cancer cells to target drug delivery [5]. Once the drug loaded nanoparticles reach the tumor sites the next objective is to effectively release the drug there. Different triggered release mechanisms like acid triggering, light triggering, heat triggering and enzyme triggering are being tried to release the chemotherapeutic drug at the tumor site. Although application nanomedicine, is able to address lot of problems raised in convention chemotherapy, lot more problems are still there to be answered. Introduction of pegylated/stealth nanoparticles, increase the efficacy of anticancer drug but it has some side effects like skin toxicity, hand–foot syndrome also. Passive targeting via EPR effect reduces the toxicity of anticancer drug. Nanoparticles are supposed to get accumulated in tumor tissues only, but they accumulate in lung, liver, spleen and kidney due to porous microstructure of these organs. Active targeting process has also some problems like: (i) antibody tagged nanoparticles bind to their targets so strongly that they make a barrier that won’t allow other nanoparticles to enter into the tumor sites and (ii) they are very rapidly cleared by RES system. Since there is lot of challenges in cancer drug delivery, it bears lots of potentials also. So, extensive research is going on world-wide on cancer drug delivery to solve these issues and significant mile-stone yet to be achieved. We hope with rapid



47

advancement in nanomedicine, the day is not too far when cancer will be cured completely. Further reading: 1. M. M. Robert et al, Cancer, New

York, 1993 2. S. S. Feng and S. Chien, Chem.

Engg. Sci. 58 (2003) 4087–4114 3. American Cancer Society, (2002).

Cancer Prevention & Early Detection, Facts and Figures 2002.

4. http://www.chemotherapy.com/side_effects/side_effects.jsp (visited on 24.09.09)

5. T. L. Andresen et al. Prog. Lipid Res. 44(2005) 68-97

About the author:

Mr. Manashjit Gogoi hails from Titabor, Jorhat, Assam. He did his Bachelor of Engineering in Chemical Engineering from Assam Engineering College, Guwahati and then worked in North-East Institute of Science and Technology (Formerly Regional Research Laboratory) Jorhat as a Project Assistant. Latter on he did Master of Technology in Bioelectronics from Tezpur University, Tezpur, Assam. Presently, he is working for his Doctor of Philosophy in Indian institute of Technology-Bombay. His research topic is "Temperature Sensitive Nanostructured Magnetic Materials and Nanovesicles for Biomedical Applications". ----xxxx----

A green or an evergreen revolution? Its time to think about neglected and underutilized crops Nabanita Bhattacharyya Lecturer, Nowgong College Nagaon, Assam.

There is all total 7000 edible plant species discovered so far, among which only a few species are utilized for global food security. Again, the human civilization has been using only three crops i.e. rice, wheat and maize to meet more than 50% of its dietary energy need. This narrow bio-diversity in the food basket has posed a definite threat to the food security especially in context of global climate change and population explosion. There is no doubt that substantial increase in food production could be achieved as a result of the first green revolution led by the incredible efforts of Dr. M. S. Swaminathan in 1960’s in India. In the first green revolution, scientists gave emphasis only in the three major crops i.e. rice, wheat and maize. As a result, the global food production was improved dramatically. Due to increased importance posed on the production of only a few crop species, several traditionally valued crops faced negligence in respect of agricultural R&D priorities and production policies. Such marginalization of these crops encouraged rapid loss of their genetic diversity as well as related traditional knowledge and cultural identity associated with their agricultural practices and consumption. Some examples of such neglected species with great nutritional value are minor millets and wild vegetables.

According to the concept of the

first green revolution, researchers developed new varieties of wheat and rice with the ability to produce high yields when grown with irrigation and



48

fertilizers. But, food security is currently facing tremendous challenge due to the unpredictable changes in weather and deficiency in nutritional factors. Each year, 80 million new faces have been added in world population. In 2050, world population will reach 9 billion. In present scenario, malnutrition affects 70% of the world population. India has 40% of world’s malnourished children. This statistics usher a need for the sustainability in food production which can be achieved only by evolving strategies through a second green revolution or more accurately an evergreen revolution. The themes of the sustained green revolution must be the production of value added quality food, sustainability of ecosystem and agriculture without damaging the ecological balance. Although, there are many choices of vegetables sources, many of them are neglected today because of the preference towards uniform characteristic in modern agriculture technology and marketing (Yildirim et al, 2001). It is now the peak hour to explore the genetic diversity of the underutilized or marginalized crops as well as the traditionally used wild vegetables to meet the ever increasing problem of hunger and malnutrition. New plant resources have to be preserved to broaden the biological diversity in human nutrition (Williams, 1993). Diversification of production systems by including a broader range of species can contribute significantly to improved health and nutrition, livelihoods, household food security and ecological sustainability (Qualset et al., 1995; Thrupp, 1998). More over this is the present need to explore the potentials of the underutilized and wild species to grow well in poor, marginal soils with low inputs and to withstand severe stresses arising from soil and climate. Wild plant species provide

minerals, fibre, vitamins and essential fatty acids and enhance taste and colour in diets. They can also be used to prevent chronic diseases like cardio-vascular diseases and diabetes, in the general population, as well as diseases due to under nutrition, like anaemia and stunting (Green, 1993). In this regard, they deserve special attention in R&D along with heavily focused high yielding varieties of major cereals and commodity crops. Ethno botanical studies are becoming more popular throughout the world and these studies are focused on documenting the traditional uses of plants by native cultures (Ozgen et al, 2004). This kind of approaches may provide a broader dimension to the under utilized crops.

The North Eastern part of India

is the home of several tribes with great treasures of traditional knowledge especially regarding food habit and wild medicine. Numerous wild vegetables, fruits and medicinal plants have been used by the tribes since long before to ensure nutritional and health security. One of such potential wild leafy vegetables is the Houttuynia cordata Thunb. (Saururaceae). This is a perennial herb with creeping root stock and heart-shaped leaves and available entire South East Asia including China, Japan, Thailand and North East India. This has been used

Fig.: Houttuynia cordata Thunb.



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by the local communities of this part of the world as an herbal medicine against various ailments including diarrhoea, dysentery, gonorrhoea, eye troubles, measles, skin diseases and haemorrhoids. Modern research approaches have revealed its broad pharmacological activities, including anti-leukemic, anti-oxidative, anti-mutagenic, anti-inflammatory and anti-viral effects as well as the ability of promoting immunologic function (Zhang et al, 2008). This medicinal herb has been used by the local people as a nutritive leafy vegetable also.

Although the potential of a

single species has been cited in this article, there are numerous such resources available throughout the traditional cultures still surviving in the remote corners of the modern civilization and awaiting to be explored with proper scientific measures. The alarming call is ringing in full tune to realize the importance of these species and their potentiality for solving the global problem of malnutrition. Further reading: Biospectrum 2009 - International

Symposium on Second Green Revolution: Priorities, Programmes, Social and Ethical Issues, held at Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, Kerala, India, from 2 – 4 July, 2009, organized by School of Biosciences, Mar Athanasios College for Advanced Studies, Tiruvalla (MACFAST), Kerala, India, in association with RGCB, Thiruvananthapuram, Kerala, India.

Green C (1993) An overview of production and supply trends in the U.S. specialty vegetable

market. Acta Horticulturae, 318: 41-45.

Ozgen U, Kaya Y, Coskun M (2004) Ethnobotanical studies in the villages of the district of Hica (Ptrovince Erzurum), Turkey. Economic Botany, 58: 691-696.

Williams DE (1993) Lyanthes moziniana (Solanaceae): An underutilized Mexican food plant with new crop potential. Economic Botany, 47: 387-400.

Yildirim E, Dursun A, Turan M (2001) Determination of the nutrition contents of the wild plants used as vegetables in Upper Coruh Valley. Turkish Journal of Botany, 25: 367-371.

Zhang Y, Li S, Wu X (2008) Pressurized liquid extraction of flavonoids from Houttuynia cordata Thunb. Separation and Purification Technology, 58: 305-310.

About the Author

Ms. Nabanita Bhattacharyya has been working as a lecturer in Plant Physiology and Biochemistry, Department of Botany, Nowgong College, Assam. Her research area includes Stress Physiology, Phytoremediation, Environmental Physiology and Biochemistry. Currently she is doing her PhD in the Dept. of Biotechnology, Gauhati University, Assam under Prof. S Sarma. Email: [email protected] ----xxxx----



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Thesis Abstract of Babita Baruwati, Ph.D. Thesis Title: “Studies on the Synthesis, Characterization, Surface Modification and Application of Nanocrystalline Nickel Ferrite” Research Guide: Dr. S.V. Manorama, Indian Institute of Chemical Technology, Hyderabad- 500 607, India.

Man’s quest towards revealing

new facts or things is unlimited. This often leads to the improvement of the earlier existing ideas. We talk about new ideas, debate on them, try to prove them and then if they are plausible we accept them. It is for this reason that nano science and technology is the focus of much discussion these days. Moreover, nanotechnology now encompasses almost all the branches of science whether it is physics, chemistry, biology or engineering. There are various branches of nanotechnology that have now entered the popular lexicon; for example, nano materials, nano engineering, and nano medicine. The reason behind the thrust towards the development of materials in the nanometer scales is the extraordinary change in the conventional physical and chemical properties when brought to the nanometer region. This change in the physical and chemical behavior of the nanomaterials when compared with the bulk counterparts is achieved due to the enormous increase in surface to volume ratio.

In the race of development of

nanomaterials, ferrites are attracting

much attention by virtue of their unique electronic or physical structure, and multidisciplinary applications. Due to their high electrical resistivity values these materials are in great demand as high frequency magnetic materials.

Nanocrystalline ferrites with

particle sizes well below the microwave skin depth offer promise as low loss materials at high frequencies. These nanomaterials are also used in various fields of electronics, as magnetic recording media, as ferrofluids, in catalysis due to their easy separation and hence reusability and also in gas sensors due to their high sensitivity towards some reducing gases like LPG, H2S etc at very low operating temperatures. Considerable researches are being directed towards using these nanomagnetic particles as MRI contrasting agents, in drug delivery systems and in environmental remediation. Recently there is a report on the use of NiFe2O4 as a promising material for spintronics. The physical and chemical properties of spinel nanocrystals are greatly influenced by the synthesis route; this is the reason why various approaches are being adopted to produce spinel ferrites, to realize the desired properties. Over the decades research has been focused towards obtaining the required material along with other favorable physical properties. Synthetic control over the nanocrystal phase is therefore an additional degree of freedom in the search for new materials’ properties.

The present thesis is an attempt

towards the realization of the influence of synthetic conditions in the morphology of nanosized NiFe2O4 and subsequent electronic and magnetic behavior. An attempt also has been made for surface functionalization of

8. PH.D. THESIS ABSTRACT



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these nanosized NiFe2O4 to make them amenable for specific applications. This includes the use of these functionalized particles as catalyst support for the development of a magnetically separable catalyst. Also these materials are synthesized via surfactant-mediated routes to achieve excellent control over morphology and magnetic properties and to make them soluble in specific solvents so that they can be used for specific applications.

The Thesis has been divided mainly to 4 chapters.

Chapter 1 begins with an

introduction to ferrite nanoparticles with an overview of the synthetic methods, properties and applications. The reasons for the tremendous interests in ferrites, the challenges in the development of suitable synthetic methods for better control of the properties and the scientific concepts have been discussed.

Chapter 2 deals with the

synthesis of NiFe2O4 nanoparticles by hydrothermal route and the effect of reaction conditions on the conductivity behavior of the material. Here we are discussing in detail about the change in conductivity from n-type to p-type when the pH of the reaction medium has been changed keeping all other conditions identical. We observed n-type conductivity in these synthesized materials when the pH of the reaction medium was maintained at either 7 or 8. When the pH of the reaction medium has been increased to a value greater than or equal to 9, the materials starts exhibiting p-type conductivity behavior. A detailed study on the structural, morphological, electrical, magnetic and elemental analysis has been made and correlated to understand the mechanism of conductivity.

NiFe2O4 nanoparticles are synthesized via hydrothermal route at 225 οC for 2 hrs using Ni(NO3)2.6H2O and Fe(NO3)3.9H2O as precursors. The pH of the reaction medium was maintained at 7, 8, 9, 10 and 11 by the addition of NH4OH solution. The phase purity and the crystallinity of the as synthesized nanoparticles are confirmed with XRD studies. Crystallite sizes are calculated using Scherrer formula. It was observed that the crystallite size increases slightly with the increase in pH of the reaction medium. TEM micrographs of the as synthesized nanoparticles show that the particles are almost spherical in morphology and are highly dispersed. The sizes of the nanoparticles are in the range 10-12 nm that is comparable with the crystallite size calculated from Scherer formula. We have not observed any noticeable change in the shape with the different pH values.

Atomic absorption spectroscopy studies reveal that the weight percentage ratios of Fe to Ni in samples 7-10 are 2.34, 2.1, 2.06, and 1.8 respectively. This shows that the sample synthesized at pH 7 is nickel deficient, while the amount of nickel increases with the increase in pH. This may be due to the increased precipitation of Ni2+. For pH<7 the Ni2+ions would have more solubility thereby resulting in mixed phases of NiFe2O4 and Fe2O3 while for Fe3+ given very low solubility product of Fe(OH)3 not much change in its precipitation would take place under these pH conditions.

The first observation of the

dissimilar conductivity behavior in the materials synthesized at different pH values was made from the gas sensing studies. It was observed that the samples synthesized at pH 7 and pH 8



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showed a decrease in resistivity values in a reducing gas atmosphere i.e. (Ra−Rg) > 0 while those synthesized at pH 9, 10 showed a increase in resistivity values i.e. (Ra−Rg)<0. These observations are typical of n-type and p-type semiconductors respectively.

From thermo emf studies it has

been observed that the Seebeck coefficient is negative for samples 7 and 8 and positive for 9 and 10 corroborating with n-type conductivity behavior in sample 7, 8 and p-type conductivity in samples 9,10.

DC conductivity studies show that the as synthesized samples obey the Arrhenius characteristics typical of a semiconductor.

We have also observed an increase in the conductivity values of the samples with the increase in pH of the reaction medium. i.e σ7< σ8< σ9< σ10. Also we observed a transition temperature for each sample where the conductivity behavior was changing from semiconducting to metallic. The possible mechanism is discussed. To explain the differences in the conductivity types in different samples, we have put forth the following arguments on the basis of XPS analysis.

The reason for the n-type

behavior in samples 7 and 8 is attributed to the presence of Fe2+ and this conductivity is predominantly due to hopping of electrons from Fe2+ to Fe3+

. Similarly, p-type conductivity in samples 9 and 10 is attributed to the presence of Ni3+ and the conductivity is due to the hole transfer from Ni3+ to Ni2+ ions. It can be explained simply that the type of conductivity is merely due to the deficiency or excess of Ni species. Excess Ni corresponds to Fe3+

deficiency (cation vacancy) that is being compensated by change in some

of the Ni2+ to Ni3+, which is the condition prevailing at high pH and less Ni corresponds to Fe2+ compensating for Ni2+ deficiency that happens at low pH. This then explains the presence of more Ni3+ in the samples prepared at high pH viz. 9 and 10. This fact is also confirmed by our AAS analysis where the ratio of Ni to Fe increases with the increase in pH. This is also supported by the XPS analysis showing the presence of Ni3+ in the samples prepared at high pH. We further calculated the ratio of Ni3+ to Ni2+ from the areas under the deconvoluted XPS spectra for Ni and obtained values for this ratios as 0.06, 0.08, 0.11 and 0.3 for samples 7, 8, 9 and 10 respectively showing a trend of increasing Ni3+/Ni2+ ratios as pH increases. In short n-type conductivity can be represented by “Fe3+ ⇔ Fe2+”

and the p-type conductivity by “Ni3+

⇔ Ni2+”. VSM and Mossbaüer studies

reveal the magnetic properties of the samples. VSM plots shows slight ferromagnetic nature of the as synthesized samples at room temperature but the magnetization is not saturating even up to the applied field of 10,000 Gauss. The slightly ferromagnetic nature is also seen from Mössbauer spectra where we have obtained a sextet instead of a doublet. However the nature of the spectra are typical of the relaxed type, which may be attributed to the transition from ferromagnetic to superparamagnetic nature of the sample. The relaxed spectra also confirm the non-saturating nature of the hystersis loop.

Chapter 3 has been divided into two parts. In part A we have discussed about the surface functionalization of the hydrothermally synthesized NiFe2O4 nanoparticles with dopamine to ensure its high



53

dispersibility in high polar solvents like water, ethanol etc. This opens up the possibility of using these surface functionalized nanoparticles as a support for noble metal to design a novel magnetically separable catalyst system that can be used for catalysis of a number of scientifically and industrially important organic transformation reactions. Characterization of the prepared catalyst system has been done with XRD, FTIR, TEM, ICP-AES, XPS and VSM. The excellent efficiency and reusability of the catalyst system for a wide range of organic reactions have been discussed in the part B. These include hydrogenation of a range of unsaturated organic compounds, Heck coupling reaction and Suzuki reaction.

Anchoring of dopamine molecules on the surface of NiFe2O4 has been achieved via refluxing.

P dD A in H 2O

R eflux/ Sonication

Na2 Pd C l4

D il N H 2N H 2

pH -9

Ferrite H 2N term inated Ferrite Pd on H 2N term inated Ferrite

Schematic representation of the surface modification as well as anchoring of Pd nanoparticles on the surface of NiFe2O4 nanoparticles

Confirmation about the

anchoring of the organic moiety on to the surface of the NiFe2O4 nanoparticles has been confirmed by FTIR spectroscopy. Pd nanoparticles are then anchored to the free amine group of dopamine molecules by taking Na2PdCl4 as the Pd source and then reducing it by using hydrazine monohydrate. Below is the schematic representation of the total reaction procedure.

The weight percentage of Pd

before reaction in NiFe2O4-DA-Pd is

found to be 8.54 by Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP–AES) analysis. As a representative the percentage of Pd in the catalysts after 5 cycles of reactions is 8.49 that is almost the same as the unreacted catalyst. From the ICP-AES analysis it can be inferred without any ambiguity that there is no significant loss of Pd due to leaching etc. during the reaction and it provides the excellent reusability of the catalyst.

NiFe2O4-DA-Pd catalyst (a) before reaction, (b) after 3 times and (c) 5 times reactions. (d) shows the magnetic separation of the catalyst from the reaction medium.

X-ray photoelectron spectroscopy studies were carried out to establish the oxidation state of Pd in the catalyst. The Pd 3d5/2 binding energy spectra consists of a single peak at the binding energy 334.42 eV with an FWHM of 1.6 eV that is attributed to the Pd in zero oxidation state.

The magnetization Vs applied

field plot for the particles show that the particles are superparamagnetic at room temperature. The magnetization does not saturate up to the maximum



54

applied field and the coercivity is almost negligible. The magnetization results indicate the suitability of using nanosized NiFe2O4 as a magnetically separable catalyst support. The synthesized catalyst system has been used for a number of reactions namely Hydrogenation, Heck and Suzuki coupling reactions. Table 1, Table 2 and Table 3 gives the summery of Suzuki, Heck and hydrogenation reactions respectively carried out on NiFe2O4–DA-Pd catalyst.

In Chapter 4 we have made an

attempt to synthesize monodisperse and size selective NiFe2O4 nanoparticles with solvent selective dispersity. Such particles are in great demand in the recent field of technology due to the excellent control over the magnetic properties because of their size selectivity.

These particles are synthesized

by using different precursors and reaction conditions and are highly dispersible in nonpolar organic solvents. The effect of reaction conditions like temperature, ratio of surfactant, reaction time etc. on the morphology of the synthesized particles are also discussed. At the end the inferences made from the study and the scope of future work has been included. Finally appendix deals with all other works carried out during the PhD period. About the author Babita Baruwati is currently working as a research associate at United States Environmental Protection Agency, Cincinnati, OH. She finished her PhD from Indian Institute of Chemical Technology, Hyderabad in March, 2008, in Materials Science. She was a student of Gauhati University during her MSc in Physics.

Her work experience lies in the field of nanomaterial synthesis, characterization and applications in gas sensors, catalysis and environmental remediation. She has published her work till now in 17 highly reputed international journals and presented many oral and posters in various national and internal seminars including three American Chemical Society conferences. Some of her works are highly cited by other authors in international journals. Selected publications 1 Glutathione promoted expeditious

green synthesis of silver nanoparticles in water using microwaves , Babita Baruwati, Vievek Polshettiwar, Rajendar S Varma, Green Chem. 11, 926, ( 2009)

2 Magnetic nanoparticle-supported glutathione: a conceptually sustainable organocatalyst, Vievek Polshettiwar, Babita Baruwati, Rajendar S Varma, Chem Comm. 1837,(2009).

3 Self-Assembly of Metal Oxides into Three-Dimensional Nanostructures: Synthesis and Application in Catalysis, Vievek Polshettiwar, Babita Baruwati, Rajender S Varma, ACS Nano 3, 728–736 (2009).

4 Bulk Synthesis of Monodisperse Ferrite Nanoparticles at Water-Organic Interfaces under Conventional and Microwave



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Hydrothermal Treatment and Their Surface Functionalization Babita Baruwati, Mallikarjuna N. Nadagouda, Rajender S. Varma J. Phys Chem C, 112, 18399, (2008).

5 Monodispersed NiFe2O4 Nanoparticles: Nonaqeous Synthesis and Characterization, Babita Baruwati and Sunkara V Manorama Materials Chemistry and Physics, 112, 631–636) (2008)

6 “Heck and Suzuki coupling facilitated by Pd on amine terminated NiFe2O4: A magnetically separable catalyst” Babita Baruwati, Debanjna Guin, Sunkara V Manorama, Organic Letters 9, 5377 (2007)

7 “Pd on Amine Terminated Ferrite Nanoparticles: A Complete Magnetically Recoverable Facile Catalyst for Hydrogenation Reactions” Debanjan Guin, Babita Baruwati, Sunkara V Manorama, Organic Letters, 9, 1419 (2007)

8 “Hydrothermal synthesis of highly crystalline ZnO nanoparticles: A competitive Sensor for LPG and EtOH” Babita Baruwati, D Kishore Kumar & Sunkara. V. Manorama, Sensors and Actuators B 119, 676 (2006)

9 “S, N and C doped titanium dioxide nanoparticles: synthesis, characterization and redox charge transfer study” K. Madhusudan Reddy, Babita Baruwati, M. Jayalakshmi, M. Mohan Rao and Sunkara V Manorama Journal of Solid State Chemistry, 178, 3362 (2005)

10 “Tailored conductivity behavior in nanocrystalline NiFe2O4” Babita Baruwati, K Madhusudan Reddy, Sunkara V Manorama, Rajnish K Singh, Om Parkash, Applied Physics Letters, 85, 14 (2004)

----xxxx----

Thesis Abstract of Saitanya Kumar Bharadwaj, Ph.D. Thesis Title: “Synthesis, Structural Evaluation and Studies of Reactivity of Heteroperoxovanadates (V) And Development of Solid acid Catalysts for Organic Transformations” Research Guide: Prof. Mihir K Chaudhuri, Department of Chemistry Indian Institute of Technology Guwahati, Assam–781039, India.

This thesis is based on the results of studies of a few chosen aspects of peroxovanadium chemistry and heterogeneous catalysis. The text has been distributed over five chapters. The introductory chapter of the thesis presents an overview of different aspects of peroxovanadium chemistry with special reference to haloperoxidase activity and insulin mimesis, and a brief account on the importance of heterogeneous catalysis for organic transformations. The second chapter provides experimental procedures, source of reagent and solvents, and particulars of the equipment and instruments used. Chapters 3 to 5 present the newer results gathered during the Ph.D. research.

Chapter 1: Introduction and Scope of the Work

This Chapter highlights the importance of peroxovanadium related coordination chemistry and gives an account to their reactivity, biochemical relevance and commercial importance, especially with reference to haloperoxidase activity and insulin mimetic action of peroxovanadium compounds.

Briefly speaking vanadium haloperoxidases (VHPOs) are the



56

enzymes that catalyze the oxidation of halides by H2O2. VHPO possesses trigonal bipyramidal geometry around vanadium in the native site and a distorted tetragonal structure in the active form (peroxo-intermediate). Structural characterization has revealed that vanadate is covalently linked to the Nε of the imidazolyl moiety of a histidine amino acid, and further through hydrogen bonds to a variety of amino acid side chains (e.g. Arg, His, Ser, Lys) and interstitial water in the proximity of the active center. Special emphasis has been put on to the understanding of chemistry of bromoperoxidase activity because of its remifications on the synthetic applications to bromo-organic compounds having commercial importance. Quite apart from the activity highlighted above, peroxovanadium complexes are also found to be potential clinical alternatives of insulin for the treatment of diabetes. Hence, insulin-mimetic action of peroxovanadium complexes is briefly reviewed in this Chapter. Besides bio or abiomimetic catalysis, development of abio catalytic systems is yet another domain of contemporary importance. This aspect, with reference to heterogeneous catalysis and its direct bearing with Green Chemistry and Green Technology has been dully projected in this Chapter. The potential advantages of heterogeneous catalyst in organic reactions are (a) good dispersion of active sites, (b) constraints of the pores, (c) easier and safer to handle, d) easier to remove from the reaction mixture and (e) reusability. Among various heterogeneous catalysts, the importance of solid acid catalyst has been emphasized in this Chapter. The effects of supported material in reactivity of solid acid catalysts have

been also discussed, highlighting the importance of alumina

and titania. Solid acid catalysts are found to replace not only mineral acids but also catalyze the organic reactions.

After laying the foundation as indicated above, the scope of work in the present Ph. D research have been brought out very clearly.

Chapter 2: Materials and Methods

The sources of chemicals and solvents, methods for quantitative chemical estimations, determination of elements and particulars of all equipment used for physico-chemical studies are provided in this Chapter. The characterization was done using a variety of physico-chemical techniques, for example, elemental analysis, IR, UV-Visible, Raman, GC-MS, NMR, SEM, XRD.

Chapter 3: Synthesis, Characterization of newer Peroxovanadates and Study of their Reactivity

With the increased interest as (i) model for vanadium haloperoxidase, (ii) compounds with insulin mimetic or antitumor activity and (iii) stoichiometric or catalytic oxidants of organic compounds, a myriad of peroxovanadium compounds has been studied in the last two and a half decades. In continuation to our interest in the chemistry of peroxo and heteroligand peroxo compounds, the following work has been done as a part of the present Ph.D. research.

Accordingly, this Chapter focuses on the synthesis and characterization of newer peroxo-vanadium complexes with heteroligands such as 3,5-dimethyl pyrazole and citric acid, at or near physiological pH. Interestingly, while synthesizing the abovementioned



57

compounds, we have often encountered the formation of a stable µ-hydroxo peroxovanadate (V), [VO(O2)2(OH)(O2)2OV]3- species. This observation and akinness of OH- to F-, directed us to synthesize the corresponding µ- fluoro complex.

The Chapter has been subdivided into four subsections. The first three subsections have been organized to discuss the synthesis and characterization of different heteroperoxovanadates with heteroligands like 3,5-dimethyl pyrazole, citric acid and fluoride, respectively, whereas in the fourth subsection, the reactivities of all these compounds have been illustrated.

3.1 Synthesis and Characterization of Oxodiperoxo-dmpz-vanadates (dmpz= 3,5 dimethylpyrazole)

The complexes DmpzH[VO(O2)2(dmpz)] (1), K[VO(O2)2(dmpz)] (2) and Na2[V2O2(O2)4(dmpz)] (3), have been synthesized from aqueous solutions. Typically, V2O5 or AVO3 was reacted with dimethyl pyrazole(dmpz) and hydrogen peroxide at a pH ca. 5 or 5.5 to afford yellow crystalline and microcrystalline compounds.

Characterization of the compounds 1-3 was made by elemental analysis, IR, Raman, UV-Vis and 1H NMR spectroscopy. X-ray crystal structure determination of 1 and 3 has been carried out to delineate their structure.

DmpzH[VO(O2)2(dmpz)]

KVO3 (aq. soln.) K[VO(O2)2(dmpz)]

NaVO3 (aq. soln.) Na2[V2O2(O2)4(dmpz)]

dmpz, 50% H2O2

dmpz, 50% H2O2

dmpz, 50% H2O2V2O5(aq. soln.)

Scheme -1

(1)

(2)

(3)

Figure 1 Ortep diagrams and chemdraw structures of anion of compound 1 and 3

While compound 1 is a diperoxo-pyrazole-vanadium anion with pyrazolium as the counter cation, compound 3 is a binuclear peroxovanadate with two coodinatively nonequivalent vanadium atoms and less commonly encountered µ-η1: η2-O2 group. The binuclear unit with µ-η1: η2-O2 group in compound 3 is rather uncommon in vanadium chemistry.

Compound 1 and 3 crystallize in the monoclinic P2(1)/c and monoclinic C2/c, respectively. In case of compound 1, the basal positions are occupied by pyrazole and two peroxo groups and the distance of vanadium from the basal plane is 0.687 Å. The V=O, V-O (peroxo) and V-N bond lengths are 1.59 Å, 1.85-1.91 Å, 2.10 Å, respectively similar to those



58

observed in some other vanadium complexes. Notably, these complexes constitute examples of rather less frequently synthesized hexa-coordinated peroxovanadates (V).

The crystal structure of compound 1 shows both intra and intermolecular H-bonding (Figure 2). As expected, the hydrogen from the protonated nitrogen in the ligated pyrazole forms H-bond with the peroxo group of neighboring peroxovanadates (N-H···O2, 2.040 Å) and the counter pyrazolium cation forms hydrogen bonds with two peroxo groups (N-H···O2, 1.813 and 1.837 Å) from different peroxo-vanadates.

Figure 2 Hydrogen bonding network in complex 1

Density Funtional Theory (DFT) has been used to investigate structural and electronic properties, and reactivity of 1–3. Structure optimizations were performed using both VWN and BLYP functionals. The bond lengths and angles matched with the experimental results. The electrophilicity of all complexes has been calculated, and found to be 6.28, 1.84 and 5.19 for compounds 1, 2, and 3, respectively. These results are in line with the results of our experimental studies, as discussed in section 3.4 of this Chapter.

In VHPO, the peroxo group is activated by hydrogen bonding being formed by amino acid side chains. Compound 1 forms H-bonding with pyrazolium N-H (c.f. haloperoxidase structure). Further from DFT calculations, the proton of pyrazolium

cation has been found to be labile between the nitrogen of pyrazole and the peroxodic oxygen thus, activating the peoxo group for nucleophilic attack. Compound 3 having the µ-η1: η2-O2 is found to be more electrophilic than compound 2. The electron density of the bridging peroxo group being pulled by V(V) (d0-Lewis’ acid) makes the peroxo group more prone to nucleophilic attack.

Like Bisperoxovanadium imidazole monoanion, reported by Crans et.al, (JACS, 1997, 119, 5447) the compound 1 has been found to show highly encouraging insulin mimetic activity. Several in vitro as well as in vivo experiments confirmed glucose uptake upto 2800 µg/mL by this compound.

Section 3.2 Synthesis and Characterization of oxo-peroxo-citrato-vanadates

The synthesis of citrato(peroxo)vanadates(V) has been shown to be highly pH dependent. Reaction of aqueous solutions of metavanadate or vanadium pentoxide with citric acid (CA) at ca. 4oC with the molar ratio V: CA:: 1:1.5 for one hour yielded the citratovanadates A2[V2O4(C6H6O7)2].2H2O [A = Na(4), K(5), NH4(6)] whereas maintenance of the molar ratio of V: CA: H2O2 at 1: 1.2 :4 results into citrato-monoperoxovanadates, A2[V2O2(O2)2(C6H6O7)2].2H2O [A = Na(7), K(8), NH4(9)]. The pH was maintained in the range of 3-5 by adding the corresponding alkali solution, AOH (20% for A= Na or K; 2.5% for A= NH4). A similar reaction with V: CA: H2O2 being maintained at 1: 1.2: 8 at pH 7.2 afforded diperoxovanadates(V), Na3[VO(O2)2(C6H6O7)].4H2O (10). The corresponding K+ and NH4

+ salts could not be synthesized as of now.



59

Attempts to prepare these salts have resulted to the µ-hydroxo peroxovanadates. The pH at was fixed at 7.2 in order to go close to the physiological pH. Notably, the sodium alt of citrato(diperoxo)vanadate(V) is the first example of this kind. The crystal structures of compound (4) and (8) have revealed that the bond angles and bond lengths are similar to those reported earlier.

Section 3.3 Synthesis and Structural Evaluation of µ-hydroxo and µ-flouro peroxovanadates

The expedient synthesis of both A3[VO(O2)2(OH)(O2)2OV], [A = Na(11), K(12), NH4(13)] and A3[VO(O2)2(F)(O2)2OV], [A = Na(14), K(15), NH4(16)] require vanadium pentoxide or metavanadate, hydrogen peroxide, and alkali fluoride for the later. The characterizations of all compounds were made by elemental analysis, IR and UV-Vis spectroscopy. X-ray crystal structure determinations were done to delineate the structural feature.

Although the ORTEP diagrams of compound 12 and 14 show symmetric dinuclear complexes, there are differences in the bond lengths and bond angles. The compounds 12 and 14 crystallize in the monoclinic space group P2(1)/c with four molecules in the unit cell. Each vanadium atom in compound 12 and 14 are coordinated with two peroxo ligand in a C2v fashion and one oxo group. However, the differences in the structure come from the presence of bridging hydroxo or fluoro group. An independent confirmation of presence of fluorine was done by 19F NMR spectroscopy. A singlet peak at 77.6 ppm (with reference to C6F6) was observed for compound 14 as well as for 15 and 16.

Figure 4 ORTEP diagrams of anions of complexes 12 and 14.

Section 3.4 Studies of Reactivity

Peroxo-metal complexes are reported to bring about a variety of oxidation/ oxygen transfer reactions such as sulfides to sufoxides and sulfones, hydrocarbons to alcohol, olefins to epoxides, alcohols to aldehydes and ketones. In this section reactivity of the newly synthesized complexes, DmpzH[VO(O2)2(dmpz)] (1), K[VO(O2)2(dmpz)].H2O(2), Na2[V2O2(O2)4(dmpz)].H2O (3), A2[V2O4(C6H6O7)2].2H2O [A = Na(4), K(5), NH4(6)], A2[V2O2(O2)2(C6H6O7)2].2H2O [A = Na(7), K(8), NH4(9)], Na3[VO(O2)2(C6H6O7)]. 4H2O (10), finally A3[VO(O2)2(OH)(O2)2OV] [A = Na(11), K(12), NH4(13)], and A3[VO(O2)2(F)(O2)2OV] [A = Na(14), K(15), NH4(16)] has been carried out with respect to oxidation of bromide,



60

Catalyst, H2O2 , H+

3-4 hrs

sulfide, alcohol and also bromination of chalcones.

An internal comparison of the results has been made to enable us comment on their relative efficiency. The reactivity order of the catalysts is found to be as follows:

Na2[V2O2(O2)4(dmpz)] (3) > DmpzH[VO(O2)2(dmpz)] (1) > K[VO(O2)2(dmpz)] (2) > Na3[VO(O2)2(C6H6O7)].4H2O (10) > A2[V2O4(C6H6O7)2].2H2O [A = Na(4), K(5), NH4(6)] > A2[V2O2(O2)2(C6H6O7)2].2H2O (A = Na(7), K(8), NH4(9) > A3[VO(O2)2(OH)(O2)2OV], [A = Na(11), K(12), NH4(13)] > A3[VO(O2)2(F)(O2)2OV], [A = Na(14), K(15), NH4(16)]. Chapter 4: Oxidative Extraction of Bromide from ‘Sea Bittern’ and Bromination of phenol directly with sea bittern by bio-mimicking catalysis

It is now well established that the naturally occurring bromoorganic compounds in marine aquatics are catalyzed by VBrPO enzymes in presence of H2O2 followed by bromination of the organic substrates. However, synthetically bromoaromatic compounds are prepared by bromination with molecular bromine which has been a cause of great environmental concern. Taking cues from the bromoperoxidase activity and keeping environmental safety in mind in conjunction with knowledge and experience that we gained in the peroxovanadium chemistry, it was possible to develop newer and eco-friendly brominating agents i.e. tribromides, “the store house of bromine” and bromination protocols from a solution of KBr or NH4Br. In the present Ph.D. work, like my predecessor, it has been possible to

extract bromide from “bittern” (Sea water), the natural source of bromide and also demonstrate a catalytic protocol for bromination of phenol with sea water without external addition of Br -.

In order to make the presentation more articulate, this Chapter has been divided into two sections. While Section 4.1 includes the extraction of bromide from sea water as quaternary ammonium tribromides followed by their characterization, the methodology for oxidative organic bromination of phenol without isolating the active brominating species from sea water is incorporated in Section 4.2 of Chapter 4.

Section 4.1 Extraction of Bromide from Sea bittern: An Eco-friendly Bio-mimetic Process

The detailed experimental procedure for extraction of bromide has been laid out in this section. Tetrabutyl ammonium tribromide (TBATB), benzyltrimethyl ammonium tribromide (BTMATB), cetyltrimethylammonium tribromide (CTMATB), tetraethyl-ammonium tribromide (TEATB), and tetramethylammonium tribromide (TMATB) have all been prepared from sea water and characterized.

Figure 5 Pictorial representation of extraction of bromide from sea water A set of catalysts has been separately used to extract bromide from sea bittern. Bromide (present as MgBr2) was oxidized by H2O2 in presence of



61

each catalyst and very dilute H2SO4. The efficacy of the catalysts was assayed by the isolation of TBATB, and then the best catalyst was identified.

Section 4.2. Direct Bromination of Phenol with Sea bittern

This section is to demonstrate the bromination of phenol directly by sea bittern as a representative example. Several test runs have been carried out and the reactions were monitored by GC to calculate the yield of the reaction. Generally, bromination of phenol results in mono-, di- as well as tri- bromo phenol. However, controlling the experimental conditions, we have been able to obtain p-bromophenol selectively with 70% conversion. This appears to be a useful observation. Chapter 5: Development of Solid acid Catalysts for Organic Transformations Heterogeneous catalysis is a rapidly growing area as it assists in controlling the environmental pollution. It has many advantages like easy operation, separation, reusability and hence widely used in petrochemical industries. Among heterogeneous catalysts, solid acids have been the subject of most detailed and extensive studies. They have been introduced mainly to replace highly corrosive mineral acids in reaction medium. Hence, they are the beginners to play a significant role in the greening of fine

and pharmaceutical chemical manufacturing processes. In this regard, several solid acid catalysts have been developed for some organic transformations. While discussing industrially important organic reactions

catalyzed by solid acids, nitration and sufoxidation cannot be ignored.

Nitration of organic compounds occupies an important position in the chemical industries because nitroaromatic compounds are extensively utilized as chemical feedstocks for a wide range of useful materials. Likewise, sulfoxides are synthetically useful intermediates for the construction of various chemically and biologically active molecules including therapeutic agents such as anti-ulcer, antibacterial, antifungal, anti-athrosclertic and antihypertensive, for instance. Hence selective oxidation of organic sulfides to sulfoxides is a pivotal reaction in the sphere of organic synthesis.

This Chapter describes preparation and characterization of two newer solid acid catalysts followed by their application in selected organic transformations, viz. nitration of organic compounds and oxidation of thioethers.

(a) Preparation and Characterization of Newer Solid Acid Catalysts

Two solid acid catalysts have been developed by control heating and kneading of alumina or titania with phosphoric acid at a range of temperature 200-2200C. With the specified molar ratio, this process resulted in the formation of Al(H-2PO4)3, (A-cat) and (TiO2)5.45[Ti4H11(PO4)9].4 H2O, (T-cat) with alumina and titania, respectively. The catalysts were characterized by chemical analysis as well as IR, powder XRD, SEM/EDAX, TG/DTG analysis.

(b) Nitration of Organic Compounds with Nitric Acid

Both A-cat and T-cat serve as efficient solid acid catalysts for



62

nitration of a variety of organic substrates with nitric acid (70%) alone. The protocols are applicable to various substituted aromatic and polyaromatic compounds. Substrates possessing groups prone to oxidation preferably get oxidized rather than being nitrated.

(c) Chemoselective Sulfoxidation with H2O2 or HNO3

A variety of organosulfur compounds have been oxidized chemoselectively in presence of phosphate impregnated titania, i.e. T-cat. Terminal oxidant viz. HNO3 or H2O2, has been used. An internal comparison of the results points to the fact that T-cat/nitric acid system oxidizes simple alkyl or aryl sulfides more efficiently and selectively than the T-cat/hydrogen peroxide system. These systems chemoselectively oxidize sulfur in presence of double bond, nitrile, alcohol, aldehyde, benzylic methylene and nitrogen or sulphur atoms in a heterocyclic position. Also oxidized refractory sulfurs (DBT, 4-mehyl DBT etc), these are very important as they are found in transportation fuels. Glycosyl sulfide was easily oxidized to the corresponding sulfoxide, which are important in chemical glycosylation. About the author

Saitanya Kumar Bharadwaj is currently working as a research associate in the Chemical Engineering Department of Indian Institute of Technology Guwahati (IITG).

Recently he completed his Ph.D. working under the guidance of Professor M. K. Chaudhuri at IITG. He had a short stay at NEIST Jorhat (formerly RRL Jorhat) prior to working at IITG. He has published six papers in reputed international journals and co-inventor of one Indian Patent. He attended several national and international conferences including CRSI 2007 in Delhi University, PANIIT Global conference at California, 59th meeting of Nobel Laureates and students 2009 at Lindau Germany. Dr. Bharadwaj can be reached at [email protected]

----xxxx---- Thesis abstract of Pranjal Saikia, Ph.D. Thesis Title: Preparation, Characterization, and Evaluation of Cerium Oxide Comprised Novel Nanosized Composite oxides for Catalytic Applications Research Guide: Dr. B. M. Reddy, Inorganic and Physical Chemistry Division, Indian Institute of Chemical Technology, Hyderabad, India.

Ceria (CeO2) has been extensively employed as an important component of automotive three-way catalysts (TWC) for reducing the exhaust pollutants. Besides this, fuel cell processes, oxygen permeation membrane systems, deNOx catalysis, exhaust combustion catalysts, and catalytic wet oxidation signify the applicability of the CeO2-based materials. The most important characteristics for which CeO2 can act as a promising catalyst for these applications are elevated oxygen transport capacity by forming labile oxygen vacancies and the redox couple



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Ce3+/Ce4+ with the ability of ceria to shift between CeO2 and Ce2O3. Despite widespread applications, pure ceria is poorly thermostable and undergoes rapid sintering under high temperature conditions, which leads to loss of oxygen buffer capacity and deactivation of the catalysts. Therefore, several attempts to overcome the problem were made in the literature and are still a matter of interest. One such approach is the substitution of another metal or metal oxide into the ceria lattice, thereby facilitating the formation of mixed oxides. The combination of two metals in an oxide can lead to novel structural and electronic properties of the final oxide, consequently favouring its catalytic activity and selectivity. Particle size, phase modification, structural defects and chemical non-stoichiometry also influence the redox and catalytic properties of the ceria and its composite oxides. As a result, interest to make nanosized materials other than conventional ones is going on increasingly. Though several supported and unsupported ceria-based mixed metal oxides have been investigated, the search for the second metal/metal oxide to improve both the stability at high temperature and the chemical activity, by introducing oxygen (O) vacancies in the ceria is still a topic of intensive research. Considering this fact, the effect of a lanthanum like Tb on the properties of Ce-based oxide is worth studying. It is already reported in the literature that incorporation of terbium as promoter allows for an improvement of the redox performance of M/CeO2-based catalysts. Regarding oxidation-reduction, oxygen storage capacity and a high ability to attenuate oscillations of oxygen partial pressure in the reacting environment, terbia modified ceria has been found to posses better catalytic properties. The enhanced capacity for storage and

release of oxygen i.e., the oxygen mobility was proposed to be due to the presence of O vacancies associated with terbium incorporation to ceria lattice. The Tb takes part in the crystal defect generation and thereby O vacancies in ceria host by generating strain in the lattice. The nature of support imposes a huge influence on the physicochemical and catalytic properties of the oxide catalysts. Unsupported oxides are susceptible to a fall in the surface area and a decrease in the stability during high temperature applications. Therefore, investigation of CeO2-TbO2 mixed oxides on various supports is highly essential for better catalytic evaluation. Motivated by these facts, preparation of various unsupported and supported CeO2-TbO2 catalysts [CeO2-TbO2/M (M= Al2O3, SiO2, and TiO2)] was planned for the present investigation. Modified aqueous coprecipitation and deposition coprecipitation methods have been utilised for the preparation of the aforementioned catalysts. To study the effect of the supports on sintering behaviour of the catalysts, prepared catalysts were subjected to different calcination temperatures. Characterization of the catalysts has been carried out using various techniques like thermal analysis (TG-DTA), X-ray diffraction (XRD), Raman spectroscopy (RS), transmission and high resolution electron microscopy (TEM-HREM), UVvisible diffuse reflectance spectroscopy (UV-DRS), X-ray photoelectron spectroscopy (XPS), Ion scattering spectroscopy (ISS), temperature programmed reduction-oxidation (TPR-TPO), and BET surface area (SA). All the synthesized catalysts were evaluated for the potential oxygen storage capacity (OSC), and CO oxidation. Thus, the thesis primarily deals with the synthesis, characterization and activity



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of various unsupported and supported ceria-terbia oxides aiming at the enhancement of performance in terms of thermal stability and catalytic point of view. The thesis has been organized into six individual chapters. Chapter 1 comprised of a thorough literature survey on ceria and its composite oxides including structural, redox properties, and potential applications in catalysis with relevant references. A short introduction to catalysis in general and heterogeneous catalysis in particular is also included. Importance of supported ceria-based materials has been discussed at length in this chapter. The main objectives and the scope of the present investigation are also clearly outlined. Chapter 2 deals with the experimental procedures and the techniques employed in this investigation. The details pertaining to the preparative methodologies employed to obtain the unsupported and supported ceria-terbia mixed oxides are presented with appropriate references in this chapter. The experimental details related to BET SA, TG-DTA, XRD, RS, UV-DRS, XPS, ISS, and TPR-TPO techniques are given with necessary theoretical background. The experimental aspects of the potential oxygen storage capacity measurements and CO oxidation reaction are also described in detail in this chapter.

Fig. 1: ISS pattern of Ce-Tb mixed oxide

Chapter 3 deals with the preparation and intensive characterization of CeO2–TbO2 mixed oxide by various spectroscopic and non-spectroscopic techniques and the evaluation of the catalyst system for OSC and CO oxidation activity. The CeO2–TbO2 (80:20 mol % based on oxides) catalyst was prepared by an aqueous coprecipitation method. The sample was subjected to heat treatments from 773 to 1073 K to have information on its thermal stability. The XRD results suggest that the CeO2–TbO2 sample primarily consists of nanocrystalline cubic Ce–Tb oxides with composition Ce0.8Tb0.2O2 over all the calcination temperatures. The samples are thermally quite stable and no phase segregation was observed up to the calcination temperature of 1073 K. The Raman measurements revealed the existence of cubic ceria-terbia phase and establish the generation of defects in the lattice leading to the formation of oxygen vacancies. The XPS line shapes and the corresponding binding energies indicated that the Ce and Tb are present in both 3+ and 4+ oxidation states, the latter being predominant. Ar-ISS measurements indicated no surface enrichment of ceria on the surface of the mixed oxide. It could be confirmed from the plot of intensity ratio of Tb/Ce versus number of scans, which gave a parallel pattern (Fig. 1). The TEM-HREM results confirmed that the Ce-Tb-oxide nanocrystals have average particle dimension of ~5-6 nm when treated at 773 K, and there was a nominal increase in the particle size upon subjecting the catalyst system to 1073 K (Fig. 2). The experimental images revealed that the Ce-Tb-oxides are mainly in the cubic geometry. The UV-vis DRS measurements confer information about Ce4+ ← O2− and Ce3+ ← O2− charge transfer transitions. The redox nature of the system was



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studied with the help of TPR-TPO measurements.

Fig. 2: TEM-HREM pattern of Ce-Tb mixed oxide calcined at 1073 K The reduction temperature of the Ce-Tb-oxide was observed to be lower than that of the pure ceria and exhibited better redox properties even after severe heat treatment. The OSC of the resultant solid solution, measured by a thermogravimetric method, is found to be quite high thereby leading to remarkable CO oxidation activity (100% conversion at 773 K). The results are correlated well with the structural characterization data. All the results pertaining to CeO2–TbO2 catalysts are compiled in this chapter. Chapter 4 deals with structural and redox characteristics of CeO2–TbO2/Al2O3 samples and their evaluation for OSC and CO oxidation activity. The CeO2–TbO2/Al2O3 composite oxide (80:20:100 mol % based on oxides) was obtained by a deposition coprecipitation method. The addition of alumina resulted into remarkable stabilization of CexTb1–xO2 nano-crystals against thermal sintering at higher temperatures. Alumina remains as an inert carrier and does not form any unfavorable inert compounds with ceria or terbia. The XRD analysis of the sample calcined at 773 K revealed the presence of a cubic phase with the composition Ce0.8Tb0.2O2. There is no evidence for phase segregation up to the calcination temperature of 1073 K. The presence

of oxygen vacancies leading to the defective structure formation is revealed by Raman spectroscopic analysis. Both Ce and Tb are present in 3+ and 4+ oxidation states, as revealed by the XPS measurements. The predominance of 4+ states in both the cases is disclosed.

Fig. 3: CO oxidation activity of Ce-Tb/Al2O3 mixed oxide

Very interestingly, Ar-ISS measurement indicated surface enrichment of ceria on the surface of the mixed oxide. This may lead to enhanced catalytic activity of the catalyst system. The TEM-HREM results ascertained the formation of nanometer sized mixed oxides of Ce-Tb. The grain size does not increase above 10 nm upon increasing the calcination temperature from 773 to 1073 K. The UV-vis DRS measurements disclose information about the lowering of symmetry and consequent strain development at the cerium sites. The TPR-TPO analyses shows that the reduction temperature of the system is substantially low and even after severe heat treatment its redox property remains intact. The OSC as well as the CO oxidation activity (Fig. 3) of the resultant system is found to be quite remarkable. More details pertaining to this interesting catalytic system are presented in this chapter. Chapter 5 deals with the preparation and physicochemical characterization of CeO2–TbO2/SiO2 catalysts by



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various spectroscopic and non-spectroscopic techniques and their evaluation for OSC and CO oxidation activity. The CeO2–TbO2/SiO2 (80:20:100 mol % based on oxides) was obtained by an aqueous deposition coprecipitation method. These samples were subjected to various thermal treatments. The addition of silica remarkably enhances the surface area of the final catalyst. The XRD results suggest that the CeO2–TbO2/SiO2 sample primarily consists of nanocrystalline cubic Ce–Tb oxides with composition Ce0.8Tb0.2O2 over the amorphous SiO2 surface at all the calcination temperatures investigated (Fig. 4). However, the peak widths of the nanosized materials are so large that it is not easy to draw an exact statement whether small amounts of segregated phases are present or not. The Raman measurements also revealed the existence of cubic ceria-terbia phase and indicated the formation of oxygen vacancies as a result of lattice defects formation. The XPS patterns indicated that the Ce and Tb are present in both 3+ and 4+ oxidation states. However, stabilization of Ce(III) was observed at higher calcination temperatures. The TEM-HREM results pertaining to CeO2–TbO2/SiO2 indicated well-dispersed Ce–Tb oxide nanocrystals (~3 nm) over the surface of amorphous SiO2 matrix when treated at 773 K, and there was no apparent increase in the crystallite size upon subjecting to 1073 K. The experimental images revealed that the Ce–Tb- oxides are mainly in the cubic geometry and exhibit high thermal stability. The UV-vis DRS measurements disclose information about Ce4+ ← O2− and Ce3+ ← O2− charge transfer transitions. The TPR-TPO analyses indicated the interesting redox property of the catalyst system. The OSC as well as the CO oxidation activity of the resultant system is found

to be quite remarkable. All the results in details pertaining to this catalyst system are compiled in this chapter.

Fig. 4: XRD of Ce-Tb/SiO2 mixed oxide calcined at different temperatures. (C and T are the patterns for pure ceria and terbia respectively)

Fig. 5: Raman spectral patterns of Ce-Tb/TiO2 mixed oxide calcined at different temperatures. (C and T are the patterns for pure ceria and terbia respectively) Chapter 6 deals with the preparation, structural evolution and catalytic activity (OSC and CO oxidation) of CeO2–TbO2/TiO2 samples. The CeO2–TbO2/TiO2 composite oxide (80:20:100 mol % based on oxides) was obtained by a deposition coprecipitation method. The addition of titania resulted into enhancement of surface area of the final catalyst. In this case, the XRD results suggest that the mixed oxide calcined at 773 K primarily consists of poorly crystalline mixed oxides of Ce-Tb and TiO2-anatase phase and a better



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crystallization of these oxides occur with increasing calcination temperature. At high temperatures, however, titania does not remain as an inert carrier and form unfavorable compounds with ceria or terbia (as shown by the newly formed Raman peaks marked in Fig. 5). The exact composition of the newly formed compound(s), however, could not be confirmed by XRD and Raman measurements. The XPS measurements indicated that the Ce and Tb are present in both 3+ and 4+ oxidation states, the latter being predominant. The HREM results ascertained the formation of nanometer sized mixed oxides of Ce-Tb, whose grain size does not increase above 11 nm upon increasing the calcinations temperature from 773 to 1073 K. Information about the lowering of symmetry and consequent strain development at the cerium sites could be obtained from the UV-vis DRS measurements. The TPR-TPO analyses show the high reducibility of the system and even after severe heat treatment the redox property remains intact. The OSC as well as the CO oxidation activity of the resultant system is found to be quite remarkable. More details pertaining to this interesting catalytic system are presented in this chapter.

The satisfactory outcome of the thesis work eventually leads us to the consensus that using soft chemical routes nanometer sized ceria-terbia and different supported ceria-terbia mixed oxide solid solutions could be successfully synthesized. Physicochemical characterization of all the catalyst formulations showed that the systems are thermally quite stable, and possess very high surface area. Remarkable redox property was disclosed by the catalysts even after severe heat treatment. The oxygen

storage capacity of all the systems is substantially high, alumina supported ceria-terbia system being the best one. Accordingly, all combinations have shown potential catalytic activity for CO oxidation. In terms of conversion as well as light-off temperature (50% conversion), all the investigated combinations could be promising catalysts for use in modern TWC formulations. About the author:

Dr. Saikia was born in Na Ali Dhekiajuli, Jorhat. He received B.Sc. (Chemistry) degree from N.N. Saikia College, Titabar and M.Sc. (Inorganic Chemistry) degree from Cotton College, Guwahati. He was a recipient of NET-JRF (CSIR) fellowship in the year 2004. He obtained his Ph.D. degree from Osmania University, Hyderabad in 2009. He completed his thesis work at Indian Institute of Chemical Technology (IICT), Hyderabad under the supervision of Dr. B.M. Reddy. He was a DST-DAAD Exchange fellow to Ruhr University, Bochum, Germany for three months. He has worked as a post doctoral fellow at University of Cincinnati, USA.

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* Every time you smile at someone, it is an action of love, a gift to that person, a beautiful thing. * Yesterday is gone. Tomorrow has not yet come. We have only today. Let us begin.

---Mother Teresa



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1. Dr. Bipul Ch. Sarma,

Bipul Ch. Sarma, son of Gobinda Nath Sarma and Ranu Debi, was born in Malikuchi, Nalbari District of Assam, India. He received his primary and secondary school education in Nalbari. He then completed his intermediate education from Nalbari College, and B. Sc. from B. Borooah College, Guwahati. After the completion of his M.Sc. (in Organic Chemistry) from Cotton College, Gauhati University, Guwahati, in 2003, he joined as junior research fellow in a DST sponsored project at Indian Institute of Technology, Guwahati under the supervision of Prof. J. B. Baruah during February 2004 to June 2004 and then he moved to the School of Chemistry, University of Hyderabad to pursue the Ph.D. degree in 2004 under the supervision of Prof. Ashwini Nangia. He qualified CSIR-UGC-National Eligibility Test for Junior Research Fellowship (JRF) held in June 2003 and was awarded research fellowship by the Council of Scientific and Industrial Research (CSIR) during 2004-2009 (JRF and SRF). He is the recipient of Dr. K. V. Rao Scientific Society Annual Research Awards for Young Scientist 2009 under the category of Chemistry and Allied Sciences. Recently he completed his Ph.D. thesis entitled "Structural and Thermal Analysis of Organic Solids" and published over nine articles in the reputed international journals.

2. Ms. Bulumoni Kalita

Ms Bulumoni Kalita is presently working as a CSIR senior research fellow at Department of Chemical Sciences, Tezpur University (TU), Assam. She obtained her B.Sc. degree in Physics from Cotton College, Guwahati (First class with distinction; 2000) and M.Sc. in Physics specializing in Condense Matter and High Energy Physics from Gauhati University (First class 2nd position; 2003). She worked at Physics Department of Indian Institute of Technology, Guwahati for a couple of months as research fellow. Subsequently, she joined the research group of Dr. Ramesh Ch. Deka in 2005 in the Department of Chemical Sciences, TU as a junior research fellow and shortly submitting her thesis entitled “Structural and Electronic Properties of Bare and Supported -Palladium Nanoclusters: A Density Functional Approach”. Before her doctoral studies she qualified CSIR-UGC NET and GATE examination in 2004 and 2005, respectively. Her principal research interests lie in the fields of computational study of small metal clusters and related to that. She is currently investigating the structural and electronic properties of palladium nanoclusters as well as their interaction with small probe molecules viz. carbon monoxide, oxygen etc. via density functional methods. She has extended her study to understand the changes in

9. MEMBER’S FACE



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various structural and electronic properties of some of the stable palladium clusters on zeolite support and their role in catalytic activities. Her research has been published in prestigious journals like Journal of American Chemical Society, Journal of Physical Chemistry C, etc. She has attended and presented her work at various national and international conferences. 3. Mr. Bhargab Das

Bhargab Das was born on 16th May, 1979 at Gauripur, Dist. Dhubri, Assam. He did his schooling from P. C. Institution H. S. School. Then he completed his Higher Secondary and Bachelor’s Degree from B. N. College, Dhubri. He has completed Master’s degree in Physics from Gauhati University, Guwahati, Assam in March 2003. In January 2005, he joined Indian Institute of Technology Delhi in order to pursue Ph.D. degree in Photonics. Shortly, he is going to submit his thesis entitled “Investigations on high density holographic data storage and content-addressable search” working jointly under the guidance of Dr. Joby Joseph (Associate Professor, Physics Department, IIT Delhi) and Prof. Kehar Singh (Emeritus Fellow, Physics Department, IIT Delhi). He has published 6 research articles in peer reviewed international journals and presented 7 papers in various international/national conferences. He qualified GATE in 2003 and CSIR-UGC NET in December 2003.

Recently, he has received the 2009 OSA Foundation travel grant of $ 1000 in order to attend an international conference in USA. His research interests are: • Holographic data storage and content-addressable searching, Volume holographic correlators, Imaging through volume holography. • Digital holography and three-dimensional imaging, digital holographic microscopy, digital holography for bio-medical imaging. • Have strong desire to work in the field of 3D imaging through holographic techniques, 3D image processing, 3D displays and integral imaging. • He also has interests in various interdisciplinary studies. Availability of informative literature and multidisciplinary atmosphere at IIT Delhi has also attracted him towards the fascinating fields of biomedical imaging, biophotonics, medical optics, nanophotonics etc. 4. Ms Moyurima Borthakur

Ms Moyurima Borthakur was born and brought up in Jorhat, Assam did her schooling from Hemalata Handique Memorial Institute, Jorhat and completed her higher secondary (1998) from Jagannath Baruah College, Jorhat. She obtained her B.Sc. degree in Chemistry from Govt. Science College, Jorhat (First class 2nd position; 2001) and M.Sc. in Organic Chemistry from Gauhati University (First class 1st position; 2003). In 2004, she joined North East Institute of Science and



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Technology (NEIST), Jorhat and started her Ph.D. work as CSIR-JRF (2005) under the guidance of Dr. Romesh Chandra Boruah, Sc-G, Head of Medicinal Chemistry Division. She has completed her thesis work on “Studies on Conjugated Carbonyl Compounds and Related Systems. Synthesis of Some Steroidal Aza Heterocycles.” Her research work was designed to utilize conjugated carbonyl compounds for the synthesis of some novel steroidal and non-steroidal aza heterocycles using newer methodologies. Her work was further extended towards the bioreduction of organic compounds. She has published several papers in international referred journals along with some Indian Patents being filed. She has attended and presented at many places in India on her work at many national and international conferences. She was awarded the Best Performing SRF of NEIST, Jorhat for the year 2008-09. Very soon, she will be joining as a Research Scientist at Jubilant Chemsys, Noida.

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BEAUTY IN SCIENCE

I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding of a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.

Sir Isaac Newton (1642-1727) English physicist, mathematician.

The scientist does not study nature because it is useful; he studies it because he delights in it, and he delights in it because it is beautiful. If nature were not beautiful, it would not be worth knowing, and if nature were

not worth knowing, life would not be worth living.

Jules Henri Poincaré (1854-1912) French mathematician.

Science is not formal logic–it needs the free play of the mind in as great a degree as any other creative art. It is true that this is a gift which can hardly be taught, but its growth can be encouraged in those who already posses it.

Max Born (1882-1970) German Physicist. Nobel Prize, 1954.

... they are ill discoverers that think there is no land when they can see nothing but sea.

Francis Bacon (1561-1626) English essayist, philosopher.

One thing that makes the adventure of working in our field particularly rewarding, especially in attempting to improve the theory, is that... a chief criterion for the selection of a correct hypothesis... seems to be the criterion of beauty, simplicity, or elegance.

Murray Gell-Mann (1929- ) U. S. Physicist (Nobel Prize, 1969).

All of physics is either impossible or trivial. It is impossible until you understand it, and then it becomes trivial.

Ernest Rutherford (1871- 1937) English physicist, born in New Zealand. Nobel prize for chemistry 1908.

The aim of science is to seek the simplest explanation of complex facts. We are apt to fall into the error of thinking that the facts are simple because simplicity is the goal of our quest. The guiding motto in the life of every natural philosopher should be ``Seek simplicity and distrust it.''

Alfred North Whitehead (1861-1947) English mathematician.



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Abdul Wahab J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague

I am not sure about the quality of the materials of NE Quest issues. But a striking trend is clear after the release of 10 issues so far. When the NE Quest was started there were around 100 members and the number of articles published at the beginning issues were 10−11. Now after 3 years, forum members are swelled to more than 300, but unfortunately the numbers of article contribution are decreasing to 5−6. So this is not a healthy sign for a vibrant forum. Therefore, I request valuable members for more participation, may be with smaller articles, because no body publish here their original research or results. Buljit Buragohain Research Scholar, Centre for Energy, Indian Institute of Technology Guwahati, Assam I am very happy to become a member of the NE India Research Forum. It is really a very good initiative. The aim of the forum is praiseworthy. The newsletter "The N. E. Quest" published by NE India Research Forum is very informative. It will be very helpful to the students of North East India, if we print the newsletter and distribute in the libraries of colleges and universities. Editorial Addition It is my great pleasure to write a few lines on the North East India Research Forum and the N.E. Quest, the

newsletter of the forum. I have been associated with the forum from its inception in 2004. Initially we had very few members, but at present the forum has 308 members after five years of its birth. We have been organizing couple of discussions through the forum in different times and taking steps for its development. Recently some forum cells have also been started in the universities and colleges of north east with the initiative of some of the senior forum members. We would like to set up many more in the near future. And also we are planning to make an advisory board for the N.E. Quest soon after discussion for maintaining the quality of contents in the newsletter. However, it is very unfortunate that we have received meagre response for articles, science news and even for views and comments on the forum and N.E. Quest. Therefore, I request all the respected members to contribute to make the newsletter a successful one.

10. READER`S PAGE



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Country: Japan Top 30 Japanese Universities: 1. University of Tokyo http://www.u-tokyo.ac.jp/index_e.html 2. Kyoto University http://www.kyoto-u.ac.jp/en 3. Osaka University http://www.osaka-u.ac.jp/en 4. Tokyo Institute of Technology http://www.titech.ac.jp/english/ 5. Tohoku University http://www.tohoku.ac.jp/english/ 6. Keio University http://www.keio.ac.jp/ 7. Kyushu University http://www.kyushu-u.ac.jp/english/index.php 8. Nagoya University http://www.nagoya-u.ac.jp/en/ 9. Hokkaido University http://www.hokudai.ac.jp/index-e.html 10. Tsukuba University http://www.tsukuba.ac.jp/english/ 11. Kobe University http://www.kobe-u.ac.jp/en/ 12. Chiba University http://www.chiba-u.ac.jp/e/ 13. Waseda University http://www.waseda.jp/top/index-e.html 14. Hiroshima University http://www.hiroshima-u.ac.jp/ 15. Kanazawa University http://www.kanazawa-u.ac.jp/e/ 16. Okayama University http://www.okayama-u.ac.jp/index_e.html 17. Tokyo University of Science http://www.sut.ac.jp/en/ 18. Tokyo Metropolitan University http://www.metro-u.ac.jp/index-e.html 19. Tokyo Medical and Dental University

http://www.tmd.ac.jp/TMDU-e/ 20. Osaka City University http://www.osaka-cu.ac.jp/english/ 21. Niigata University http://www.niigata-u.ac.jp/index_e.html 22. Kumamoto University http://www.kumamoto-u.ac.jp/univ-e.html 23. Tokushima University http://www.tokushima-u.ac.jp/english/ 24. Osaka Prefectural University http://www.osakafu-u.ac.jp/english/ 25. Gifu University http://www.gifu-u.ac.jp/english/ 26. Tokyo University of Agriculture and Technology

http://www.tuat.ac.jp/index-e.html 27. Yokohama National University http://www.ynu.ac.jp/index_en.html 28. Yamaguchi University http://www.yamaguchi-u.ac.jp/english/ 29. Nagoya City University http://www.nagoya-cu.ac.jp/english/ 30. Kagoshima University http://www.kagoshima-u.ac.jp/contents/english/ Internationally Reputed National Laboratories (Selected) 1. National Institute of Advanced Industrial Science and Technology (AIST)

http://www.aist.go.jp/index_en.html 2. National Institute for Materials Science http://www.nims.go.jp/eng/ 3. RIKEN (The Institute of Physical and Chemical Research)

http://www.riken.go.jp/engn/index.html 4. National Institutes of Natural Sciences http://orbitalphase.com/english/index.html 5. National Institute for Environmental Studies

http://www.nies.go.jp/index.html

11. HIGHER STUDIES ABRAOD



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Commonwealth Split-site Doctoral Scholarship for Indian Students 2010 The Commonwealth Scholarship Commission, United Kingdom has offered Commonwealth Split-site Doctoral Scholarships tenable in the United Kingdom for the year 2009-2010. These scholarships are available in all disciplines including Medicine and Dentistry. Eligibility: Citizen and Residency: Candidates should be citizen of India. Qualification Requirement : Hold by 1st October 2010, a first degree of upper second class Honours standard (or above) or a second class degree and a relevant postgraduate qualification which will normally be a Master’s degree AND in the fields of medicine and dentistry, have qualified between 1 October 2000 and 1 October 2005. Duration: 12 months period of study or two six months periods. Please follow the link below: http://www.ugc.ac.in/more/splitedoctoralship.pdf PhD position in Bioinformatics/ Molecular Evolution, ETH Zurich Three-year Ph.D. studentship is available at the Computational Biochemistry Research Group (CBRG), department of Computer Science at the Swiss Federal Institute of Technology (ETH Zurich), highly reputable internationally. CBRG is a member of the Swiss Bioinformatics Institute (SIB) and benefits from SIB training courses and networking. Successful candidates will have a strong background in bioinformatics, computer science, statistics, and/or computational biology. Fluency in a major scripting language, and experience in software development is a must. Some background in biology is desirable, but interest in biology and bioinformatics is required. Candidates should be highly motivated and have the ability to work independently. As the research will involve a mix of disciplines, candidates with experience in several fields will be preferred (bioinformatics, genetics, protein structure, computational science, mathematics, physics, statistics). The successful applicant will be supervised by Dr Maria Anisimova, whose interests include a variety of topics in Molecular Evolution and Bioinformatics. To apply, please send a single PDF file to [email protected] containing: * CV (with publication list if applicable) * a scanned academic transcript (list of grades in university courses) * a short statement of research interests, mentioning research topics of master/diploma theses (not exceeding two pages) * three references Please mention “PhD position” in the subject of your e-mail. The position is open until filled (but quick response is recommended).

12. OPPORTUNITIES/ ADVERTISEMENTS/ CONFERENCES



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Postdoctoral Fellow, Touro University California Touro University - California has a postdoctoral fellowship available immediately in the lab of Miriam Gochin, in development of fusion inhibitors active against HIV. Further information on the lab can be obtained from our website: http://209.209.34.25/webdocs/TUResearch/MGochin.htm

The position requires a PhD, preferably in chemistry, analytical chemistry or biochemistry, and experience in working with peptides, and with biophysical techniques and analysis including fluorescence, NMR, and kinetics. Experience in macromolecular NMR structure determination is a plus. Please send a cover letter, resume and list of three references to [email protected].

Contact: Human Resources, Touro University California, Vallejo, CA, United States Email: miriam.gochintu.edu Postdoctoral position, University of Oklahoma Postdoctoral positions are available in the fields of bionanotechnology and nanomedicine. The successful candidates will have an opportunity to work on cancer treatment or tissue regeneration in a multidisciplinary group and at the interface of nanotechnology, biology, and medicine. The postdocs will work on one of the following projects: use biological nanofibers for bone tissue engineering; use nanoparticles and phage display to develop novel cancer therapeutics and gene delivery carriers; use nanotechnology to treat myocardial ischemia. Please visit research website: http://chem.ou.edu/Details/Chuanbin-Mao.html. Applications should be e-mailed to [email protected]. Contact: Chuanbin Mao, Chemistry & Biochemistry, University of Oklahoma, Norman, OK 73019, United States.



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13. THROUGH THE LENSE OF MEMBERS

Beauty of being together by Md. H. Rasid

Gift of nature…by P. Bharali

Jhanji river, Assam & Portrait of a village by K. Gogoi

Castle in a Swedish village by A. Adhikari



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n.e.quest vol 3 issue 3, october 2009

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