NE Quest Volume 2 Issue 1 April 2008

Newsletter of North East India Research Forum

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N. E. Quest; Volume 2, Issue 1, April 2008, 2

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www.neindiaresearch.org


Editorial…….

In April 2008, NE Quest enters its

second year of journey. In this eve, I would like to congratulate all the respected and beloved members. Hope we will continue this voyage with creating few new authors and more and more scientific contributions. It is an honour and immense pleasure for me to write the editorial of this issue of the newsletter, Northeast India Research Forum. I would like to thank all the forum members for giving me this challenging and great opportunity.

Here I want to mention two important issues of the NE region. Foremost, the situation in the NE India states, particularly in Assam becoming unstable day by day. Don’t you think that we are going to diminish gradually? Everyday we see people are killed in the NE states. I am mentioning about the recent violence and the impact in the NE states, as compared to rest of India. It’s a shame that, even world famous rhino is not safe from the poacher in Assam. Therefore Assam may be the easiest example in the world as an unsafe place. Because, we can not think to do a work selflessly. Something unusual happen, we have the easiest solution: BANDH and block out. Let it be a terrorist group or a political party or some regional unions. Who is actively looking for the improvement of our states? Finally the out come is: Poverty, Illiteracy, Superstition, etc. We, the forum members can take some initiative to solve some of the problems. At least we can try. I think science can help up to some extent. But this is not the complete answer. We have to educate ourselves and the new generation as to the cause of these horrible events. I know I am exceeding my limit of editorial, but some how we should. Because, this is our country, this is our motherland.


One other point I want to mention, about the proposed hydroelectricity projects in NE India states. Union Power Minister

Sushil Kumar Shinde recently said in Guwahati that the Government of India had completed preliminary feasibility reports of 62 hydroelectric schemes in this area with aggregate installed capacity of 30.42 MW. This power capacity is the 38% of country’s total potential. Again as reported in the newspaper and stated by the Union Minister of State for New and Renewable Energy, India has 615 small hydro power projects upto 25 MW aggregating 2108 MW as on 29-02-2008. Out of these 127 project are located in the NE states generating around 250 MW of electricity. We should welcome such major projections. Because the generation and utilization of electricity will play an advantageous role in the economy of the NE states.

From this issue we are staring a new column: Molecule and Material of the issue. Dr. Utpal Bora has suggested this column and starting with Dr. Joshodeep Boruwa’s article on an under clinical trial drug, Sagopilone. Members are encouraged to submit articles on drug molecules or specific polymer, dye, inorganic crystals, materials which have great impact on human life. Meanwhile, I would like to take this opportunity to thank Dr. Arindam Adhikari for creating NE India Research Forum and also for the help toward finishing the redacting of this issue. I gratefully acknowledge the editorial board for their constructive suggestions. I thank all the authors for their contributions on time, despite being having very busy work schedule. A special thanks to Mr. Anirban Adhikari for his effort in making the significant cover page in a very short time period. Finally I wish success and longer life of this forum.

Happy Rongali Bihu........

(Sasanka Deka) 14-04-2008



Contents

The Forum 5

North-East Indians Made Us Proud 6

News a) Science News 7 b) Forum Members in News 9

Instrument of the Issue Scanning Electron Microscopy (SEM) 10 Dr. Arindam Adhikari Some Award Winning SEM Images 13

Molecule and Material of the Issue Sagopilone: A Modified Epothilone Analogue as Promising Anti Cancer Agent 14 Dr. Joshodeep Boruwa

Article Section I. Invited Article

Zeta Potential Characteristics of an Iron Rich Kaolinite Clay 15 Mr. Pinaki Sengupta

II. Green Clean: A Hope 25 Ms. Nabanita Bhattacharyya

III. Positron Emission Tomography 27 Dr. Diganta Sarma

IV. Thermo Responsive Magnetic Nanoparticles and their Applications 29 Dr. Smriti R. Deka

V. RNA interference(RNAi) 32 Mr. Khirud Gogoi

VI. Nanoscience and Nanotechnology for Improvement of Human Lives 36 Mr. Pankaj Bharali

Ph. D. Thesis Abstract Abstract 1: Adsorption of Organic Anions on the Metal Oxide Surfaces 40

Dr. Manash R. Das

Abstract 2: De Novo Designed Molecules Based on Non-covalent Interactions: Design, Synthesis and Structural Studies 47

Dr. Pranjal K. Baruah

Information About Forum Members 51

Higher Study Abroad 52

Through the Lenses of Forum Members 57



The Forum

North East India Research Forum was created on 13th November 2004. 1. How we are growing?Today the forum comprised of a force of more than 191 researchers. 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. 3. Poll conducted and resultsNorth 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. NE-Quest Issues1. Vol. 1 Issue 1 April, 2007

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

Editor: Dr. Tankeswar Nath 3. Vol. 1 Issue 3 November 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 5. 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 organisationproposed by Mr. Khirud Gogoi.

Supporting schools in rural areas by different ways.

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, coordinator, volunteer, webmasters etc. Of course it needs more discussion and will be approved by poll.


North-East In s Madedian Us Proud


r. Prasanta K. Kalita

Dr. P. K. Kalita is Associate Professor of

e hails from Chapar, Dhuburi District of

uring the professional carrier, Dr. Kalita

We wish him a happy and long life…..

rof. Ranjan Deka

rof. Ranjan Deka is a faculty member of

rof. R. Deka did his B. Sc. in biology and

fter Ph. D., Prof. Deka became Assistant

We wish him a happy and long life…..

PD Pthe Center for Genome Information (CGI), Department of Environment Health, College of Medicine, University of Cincinnati, USA. He is one example, who moved towards the destiny of carrier step by step. He is one of the expert in the field of Human Genetics.

Agricultural and Biological Engineering at the Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign. He is expertise in water quality and environmental protection; watershed water-quality management and non-point source pollution control; soil erosion, chemical and microbial transport processes modelling and some more.

PM. Sc. in Anthropology in the Dibrugarh University, in 1970 and 1972, respectively. From the same university he obtained his doctorate degree in 1976. The topic of his Ph. D. thesis is Human Genetics.

HAssam. Dr. Kalita received his B. S. degree in Agricultural Engineering from the Punjab Agricultural University, Ludhiana, India. For the M. S. degree he went to Thailand and studied for M. S. in the Asian Institute of Technology, Bangkok. He did his Ph. D. in Agricultural Engineering in the Iowa State University, Ames, Iowa.

AAnthropologist, Anthropological Survey of India. Then he shifted to Dibrugarh University as lecturer. In 1985 he received Alexander von Humboldt Fellow and went for postdoctoral research to the Department of Human Genetics, Medizinische Hochschule Hannover, Hannover, Germany. During his research carrier he served as Assistant Professor and Associate Professor in the Department of Human Genetics, University of Pittsburgh, PA.

Dserved in many places, like, Post-Doctoral Research Associate in Iowa State University; Post-Doctoral Research Associate in USDA-ARS, Washington State University; Assistant Professor in Kansas State University; Assistant Professor in Agricultural Engineering Department, University of Illinois, etc. As a scholar and as a teacher, Dr. Kalita received more than 25 National and International Awards in USA.



Science News

North-East India:

he State Government of Assam has Tprepared a concept paper for establishing a science and technology university in the State. The Science and Technology Department of Assam is holding discussions with Education Department with this aim in view. The Assam Government is planning to set up a science city in Guwahati. It has also proposed a biotechnology park in the city during the current year. (March 28, 2008, The Assam Tribune). The Northeast is likely to have another National Institute of Technology, with the Central Government considering establishment of an institute in Manipur. Addressing the ongoing Social Editor’s Conference, HRD Ministry officials said a Central team after visiting the State has submitted its report last November. The report is under process currently, said the official. (January 29, 2008, The Assam Tribune). Yengkhom Daevson from Imphal, Manipur, has invented a unique weaving machine that makes garments without any stitches. This news came into focus in a press conference on 19th December 2007 in National Institute of Fashion Technology (NIFT), Delhi, Ministry of Textile, Government of India. A Special event organised for Y. Daevson an alumni of NIFT, who has invented “BEMM” a seamless woven garment making machine that makes woven seamless garments.It is a unique combination of fashion and innovation with technological development. With this new machine, one can combine the textile and the garment industry. There is advantage; it does not involve any stitching.

National & International News: India aims for ‘quantum jump’ in science: In the month of January, 2008, our Prime Minister Dr. Manmohan Singh has announced unprecedented funding for science education and research, saying it is a top priority for the government. He has announced a range of schemes to attract students and replenish government agencies' shrinking pool of scientific personnel. It is planned to fund 30 new Central Universities, five new Indian Institutes of Science Education and Research, eight new Indian Institutes of Technology, and 20 new Indian Institutes of Information Technology. In the next five years, Dr. Singh added, India will also be launching 1,600 polytechnics, 10,000 vocational schools and 50,000 skill-development centres. One million schoolchildren will receive science innovation scholarships of 5,000 rupees (US$130) each over the next five years, and 10,000 scholarships of 100,000 rupees per year will go to those enrolling on science degree courses. Discipline-specific education programmes will be launched in strategic sectors such as nuclear and space sciences “to capture talent at the school leaving stage itself”. (Courtesy: NatureNews) Editorial comment: We hope the announcement by our honourable prime minister will encourage, not only the present science students, but als ll motivate the o winew generation to do something in science. Everybody should welcome this effort and help the government to fulfil the motive, and of course, forgetting oppositional political views. Hope India will diminish the brain-drain by the 'quantum jump' in science.



Smallest Black hole: Astrophysicist claimed, they've found the smallest black hole so far, which is less than four times the mass of our sun and about the size of a large city. Nikolai Shaposhnikov of NASA's Goddard Space Flight Center says “This black hole is really pushing the limits. For many years astronomers have wanted to know the smallest possible size of a black hole, and this little guy is a big step toward answering that question”. The scientists found the black hole in a system in the southern constellation Ara, in our own Milky Way galaxy. This black hole probably be stronger than bigger black holes found at the centres of galaxies. It was formed by a star that ran out of fuel and shut down, collapsing due to its own gravity. The new black hole has a mass 3.8 times that of our sun and would be about 24 kilometres across, they estimate. (Courtesy: ABC Science) Scientists find host of antibiotic-eating germs: Several strains of bacteria in the soil can make a meal of the world's most potent antibiotics, researchers said, in a startling finding that illustrates the extent to which these germ-fighting drugs are losing the war against superbugs. A study of soil microbes taken from 11 sites uncovered bacteria that could withstand antibiotics 50 times stronger than the standard for bacterial resistance. George Church, a geneticist at Harvard Medical School in Boston, whose research appears in the journal Science, said “It certainly was very surprising to us. Many bacteria in many different soil isolates can not only tolerate antibiotics, they can actually live on them as their sole source of nutrition.” The bacteria were not known to attack humans, but some were close relatives, such as members of the Burkholderia cepacia complex, a group of bacteria that infect people with cystic fibrosis, and Serratia marcescens, which can cause blood infections in people with compromised immune systems. (Courtesy: NewsDaily).

Nation invests USD 208 million in N.E. education infrastructure: The central government has launched an ambitious Rs. 8.17-billion ($208 million) scheme to develop educational infrastructure in India's eight north-eastern states, according to an official report. “Of the Rs. 8.166 billion, Rs. 6.558 billion have been released so far for various educational projects in Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura,” said an official report of the central human resource development (HRD) ministry. The development plans in the northeast are centrally financed on the basis of 90 percent grant and 10 percent loan, the report said. “In addition to that allocation, Rs. 520 million was released to five universities located in the states of Meghalaya, Nagaland, Mizoram, Assam, Manipur, Arunachal Pradesh and Tripura for setting up of engineering and management faculties.” The central government converted the Arunachal Pradesh and Tripura universities into central universities in August 2007 and established a new central university in Sikkim. According to the report, Tripura Engineering College in Agartala has also been upgraded into a National Institute of Technology (NIT) and the HRD ministry will soon convert Manipur Institute of Technology into a NIT. The HRD ministry, with the help of the Indian Space Research Organisation (ISRO) and the north-eastern states has launched satellite-based educational facilities in the region aimed at increasing the knowledge base of students. On Aug 14, 2007, the satellite-based facility was started in Tripura with the help of the Edusat, a dedicated satellite of the ISRO to beam educational and training programmes in the country. (Courtesy: National Network of Education, India)



Forum Members in News

Dr. Manash R. Das, an aJorhat, qualified for the Scientist B

lumnus of RRL

position at the North East Institute of Science and Technology (formerly RRL) Jorhat. He will join the Material Science Division and will involved in the research of Surface chemistry on Metal oxide surfaces, Propensity of simple organic acid/anions at solution-vapour interface, etc. Currently he is a postdoctoral fellow at Villeneuve d'Ascq, Lille, France.

ualified for the prestigious Marie Curie fellowship. He

Dr. Pranjal Baruah q

will join Cambridge University, UK as a postdoc in October, 2008 for the same fellowship. Presently he is pursuing his Post Doctoral research in UNC Chapel Hill, USA.

hi Saikia of National Chemical Laboratory (NCL), Pune

Mr. Laks

received the best poster award at the National Science day symposium held at NCL, Pune on 28th February, 2008. Mr. Lakshi Saikia also qualified for the position of Scientist B at NEIST, Jorhat. He will join the Material Science Division. Moreover, one of his paper published in Journal of Catalysis between October-December 2007, become the Top 25 Hottest Articles. The particular paper is “Activation and reactivity of epoxides on solid acid catalysts Journal of Catalysis”, 252 (2) 2007, 148-160 Saikia, L.; Satyarthi, J.K.; Srinivas, D.; Ratnasamy, P.

njal Saikia, Ph.D. students in IICT,

Adsorbents, Bhubaneswar, 18th – 20th February, 2008".)

Mr. Pankaj Bharali and Mr Pra

Hyderabad bagged the best poster award jointly in the recent "National Workshop on Catalysis: Futuristic Materials as

Catalysts and

i Sangoram memorial endowment award is given to

Mr. Ankur Bordoloi received the Keerti Sangoram Memorial Endowment award (2008) of NCL, Pune. Keert

the best research scholars. This award carries a cash prize and a certificate of merit for four students in the area of physical & materials sciences, biological sciences, chemical sciences and engineering sciences.

a award (2008) of NCL, Pune. Dr. Rajappa award is given

Mr. Khirud Gogoi received the Keerti Sangoram Memorial Endowment award (2008) and Dr Rajapp

to the best organic chemistry paper. This award for research student carries a cash prize and a citation.

bon bond formation reactions using solid porous catalysts”.

Our

Sweet Khejur: Smriti R. Deka

Dr. Pranjal Kalita recently finished his Ph. D. from NCL, Pune. The title of his thesis is “Carbon-car

He is going to join (14th April, 2008) as a postdoc fellow in the Nano Ionics Materials Group, National Institute for Material Science (NIMS), 1-1, Namiki, Tsukuba, Ibaraki 305-0044 Japan.

Heartiest Congratulations to the Aforesaid Members: Editor

Newsletter of North East India Research Forum Newsletter of North East India Research Forum



nstrument of the issueI

(SEM)

arinda

Scanning Electron Microscopy

Dr. Arindam Adhikari [email protected]

is a microscope light to form an image, i.e. it’s a type of electron microscope that creates various images by focussing high energy beam of electrons onto the surface of a sample and detecting signals from the interaction of the incident electrons with the sample’s surface. Since their development in the early 1950's, scanning electron microscopes have developed new areas of study in the medical and physical science communities. (The SEM was pioneered by Manfred von Ardenne in 1937. The instrument was further

developed by Charles Oatley and first commercialized by Cambridge Instruments.)

In the SEM when incident beam interacts with specimen all these signals shown in figure 1 are present, but not all of them are detected and used for information. The signals most commonly used are the Secondary Electrons, the Backscattered Electrons and X-rays. In a SEM, these signals come not only from the primary beam impinging upon the sample, but from other interactions within the sample near the surface. The SEM is capable of producing high-resolution images of a sample surface in its primary use mode, secondary electron imaging. The SEM has many advantages over traditional microscopes. The SEM has a large depth of field, which allows more of a specimen to be in focus at one time. The

Scanning electron microscope or SEM that uses electrons instead of

Figure 1: Incident beam specimen interaction in SEM.



SEM also has much higher closely spaced specimens can at much higher levels. Due to the manner in

ave great depth of field yielding a nsional appearance

the surface tructure of a sample. As characteristic x-

rays

resolution, so be magnified

which this image is created, SEM images hcharacteristic three-dimeuseful for understanding s

are emitted when the electron beam causes the ejection of inner shell electrons from the sample and thus can also be used to tell the elemental composition of the sample (EDS or EDX, energy-dispersive X-ray spectroscopy). Because the SEM uses electromagnets rather than lenses, the researcher has much more control in the degree of magnification. All of these advantages, as well as the actual strikingly clear images, make the scanning electron microscope one of the most useful instruments in research today.

Figure 2: Image of SEM

In a typical SEM, electrons are thermionically emitted from a electron source [generally tungsten or lanthanum hexaboride (LaB6) cathode] and are accelerated towards an anode. Electrons can also be emitted via field emission (Field emission FE is the emission of electrons from the surface of another phase due to the presence of high electric fields). The electron beam, which

n energy ranging from a few 100 keV, is focused by one or

two condenser lenses into a beam with a

coils

of electrons and electromagnetic radiation, which can be detected to produce an image. The image consists of thousands of spots of varying intensity on the face of a cathode ray tube that correspond to the topography of the sample.

typically has ahundred eV to

very fine focal spot sized 0.4 nm to 5 nm. The beam passes through pairs of scanning

or pairs of deflector plates in the electron optical column, typically in the objective lens, which deflect the beam horizontally and vertically so that it scans in a raster fashion over a rectangular area of the sample surface. When the primary electron beam interacts with the sample, the electrons lose energy by repeated scattering and absorption within a teardrop-shaped volume of the specimen known as the interaction volume, which extends from less than 100 nm to around 5 µm into the surface. The size of the interaction volume depends on the electrons' landing energy, the atomic number of the specimen and the specimen's density. The energy exchange between the electron beam and the sample results in the emission

Figure 3: SEM image of polyaniline coated ticle.

silica para condensed phase into


Figure 4: SEM image of Velcro fibre (Image from


www.fei.com)

When a SEM is used, the column must always be at a vacuum. There are many reasons for this. If the sample is in a gas filled environment, an electron beam cannot be generated or maintained because of a high instability in the beam. Gases could react with the electron source, causing it to burn out, or cause electrons in the beam to ionize, which produces random discharges and leads to instability in the beam. The transmission of the beam through the electron optic column would also be hindered by the presence of other molecules. Those other molecules, which could come from the sample or the microscope itself, could form compounds and condense on the sample. This would lower the contrast and obscure detail in the image. A vacuum environment is also necessary in part of the sample preparatio e sputter oater. If the chamber isn't at vacuum before

the s

n. One such example is thc

ample is coated, gas molecules would get in the way of the argon and gold. This could lead to uneven coating, or no coating at all.

In the SEM, the magnification is entirely determined by the electronic circuitry that scans the beam over the specimen. Magnification can be as high as 300,000x. In principle the resolution of a SEM is determined by the beam diameter on

the surface of the specimen. The practical resolution however depends on the properties of the specimen and the specimen preparation technique and on many instrumental parameters such as beam intensity, accelerating voltage, scanning speed, distance from the last lens to the specimen (usually referred to as the working distance) and the angle of the specimen surface with respect to the detector. Under optimum conditions a resolution of even 1 nm can be attained.

Figure 5. Schematic representation of SEM

Specimen Preparation There are two basic types of SEM'

The regular SEM, requires a conductive samc sample ithou a conductive material. Three requirements for preparing samples for a regular SEM

s.

ple. An environmental SEM (ESEM) an be used to examine a non-conductive

t coating it withw



- Rem in the

- Firm- Non-

uctive. tly

1.www.en.wikipedia.org/wiki/Scanning_el

move all water, solvents, or other aterials that could vaporize while

vacuum. ly mount all the samples. metallic samples, such as bugs, plants,

fingernails, and ceramics, should be coated so they are electrically condMetallic samples can be placed direcinto the SEM.

References

High resolution scanning electron micrograph of

gold nanopyramids supported by silicon pedestals

ectron_microscope2. www.fei.com3. www.pu .htmrdue.edu/REM/rs/sem4. www.mse.iastate.edu/

This article is compiled by Dr. Arindam Adhikari, Institute of Surface Chemistry YKI and IPack Vinn Excellence Centre, Royal Institute of Technology KTH, Stockholm, Sweden.

Zinc dendritic structures formed by electro-

deposition on Cu substrates using a mixed solution

of ZnO powders and NaOH at room temperature.

Some Award Winning

SEM Images

MRS Meetings “Science as Art” Image competition. www.mrs.org

Dirty Dice Self-assembled 200 micron size nickel

dice, imaged using scanning electron microscopy in

the lower secondary electron (LEI) mode. The dice

were colorized using Adobe Photoshop.

(Collected by Editor)

An Early Morning Stroll into Woods

SEM Image of Tin Oxide Nanowires.

http://www.fei.com/


Molecule and Material of the Issue

Sagopilone: A Modified Epothilone

Djb

Analogue as Promising Anti Cancer Agent

r. Joshodeep Boruwa [email protected]

cells sometimes defend

against medication by

the cell through built-in pumta ost effective cancer d this mineffective.

anticancer substances. During this ptimization process, more than 350 iologically active epothilones were

synthesized, fromsele of its outstanding preclinical properties.

agopilone exhibits a high level of in vitro and in vivo activity against a broad range of different human tumour models, including those that are particularly sensitive to taxanes but also those that are resistant to taxanes or other commonly used chemotherapeutic agents and therefore no longer respond to these compounds.

It is well known that anticancer agents inhibit cell division and researchers have long focused on cell division, as the majority of tumors become dangerous only as a result of their unchecked growth. The first drug products introduced were the cytostatics, which typically damage cells by interfering with metabolic activity during cell division. Epothilones target a very differ ike a vice to the network of

crisscrosses the inside of the cell, the part of the cytoskeleton that both stabilizes the cell and makes it flexible.

The taxanes, already in successful use for many years now, prove that the cytoskeleton provides a suitable target for cancer medication. Originally harvested from the bark of Pacific yew trees, they are now synthesized from substances found in the needles of the European yew. Like the epothilones, the taxanes inhibit the breakdown of the cytoskeleton. But why all the effort to develop the epothilones as an alternative to the taxanes when they both target the same site? As potent as the taxanes are, they have drawbacks: tumor cells are often able to expel the taxanes via pumps before they can attack the cancer cells. Due to this tendency to develop resistance, other agents are very welcome. In addition, unlike the epothilones, the taxanes are not water-soluble and must therefore be administered in an oily solution that can induce allergies.

However the synthesis process to th molecule was very complex, But starting

m research group required a total of 39

e

Dr. J oral research fellow at FechbUniversitst Konstanz, Germany.

Cancer themselves transporting active ingredients back out of

ps. Even the mxanes, some of

rugs, are occasionally expelled in emain virtually anner and therefore r

Researchers at Bayer HealthCare are now performing clinical tests on a new substance that is not recognized by the pumps. Intensive structural modifications were performed on epothilones to overcome the limitations associated with this novel lass of c

o is

b which sagopilone was with three purchasable initial materials and

ore than 100 additional ingredients, thected for clinical development because

S individual steps to produce three initial sub-units which they then used to construct thfinished molecule. Report from Bayer Health:

Clinical experts must now prove that sagopilone is really as promising as previous studies indicate. If the results of the following clinical studies are good, cancer researcher Ulrich Klar predicts that sagopilone, either alone or together with other medications, will play an important role in getting a vice-like grip on cancer of various origins and in all of its stages. About The Author:

. Boruwa is currently a postdoctereich Chemie, ent area. They attach themselves l

protein threads that




Invited Article

Zeta Potential Characteristics of an Iron Rich Kaolinite Clay

Mr. Pinaki Sengupta [email protected] Introduction

The knowledge of Zeta potential is very much essential in respect of mineral processing and utilization. North Eastern region is endowed with various minerals like clay, limestone, graphite, coal etc. Beneficiation and utility studies are pre-requisites for meaningful utilization of these mineral resources.

Kaolin is one of the most versatile materials used in various industries. The term Kaolin is used for near-white clay deposits, which are dominantly composed of kaolinite mineral. The oldest known use of the kaolin clay is as a ceramic raw material. Presently, the clay also finds application as a coating and filler pigment for paper, as a filler

rm quartz. The nature and pro

of the i

sional arrays of silicon-o dimensional

arrays

layer inerals, one alumina or magnesia sheet

ith two silica sheets,

ch layers

for paint, rubber, insecticide, formulation of medicine, cosmetics, etc. About 80 % of the total kaolin produced worldwide is used in paper industry and the rest 20 % in ceramics, plastics, rubber, paints, insecticides, etc. Apart from these kaolinite minerals also find application in organic reactions as catalysts. Almost all the economic deposits of kaolin are contaminated by various ferrouginous and titanium-bearing minerals. Mined kaolin also

contains silica in the foportions of these impurities depend

on the mode of origin of the deposit and differs from place to place. For most modern industrial and other uses, kaolin must be extensively refined and processed to enhance certain important characteristics. Removal of iron- and titanium-bearing materials from clay and other minerals, in addition to impurities like silica, is of great interest even today.

The kaolin used in this investigation was collected from Deopani deposit (latitude 26o 14/ 27// to 26o 14/ 39// N; longitude 93o 45/ 54// to 93o 46/ 05// E) of Karbi Anglong district of Assam (India). The clay, which is rich in iron contaminants, is yet to be economically utilized because of lack of detailed characterization and beneficiation process. Before we proceed further in discussing the zeta potential characteristics

ron rich Deopani kaolin, it is essential to recapitulate the structure of clay minerals. Structure of the clay minerals Clay minerals belong to the ‘phyllosilicates’ (meaning layered silicates), having two dimenoxygen tetrahedra and tw

of aluminium-oxygen-hydroxyl octahedra as the principal building elements. The analogous symmetry and the almost identical dimensions in the tetrahedral and the octahedral sheets allow the sharing of oxygen atoms between these sheets. This sharing of atoms may occur between one silica and one alumina sheet, as is the case in the 1:1 layer minerals. In the 2:1 mshares oxygen atoms wone on each side. The combination of an octahedral sheet and one or two tetrahedral sheet is called a layer. Several su



are then stacked together face-to-finterlayer cations, to build up the unit cells

as, smectite or :2 clay

atic sketch of the olinite and smectite

tic representation of the ents in a ‘unit cell’ of the clay

nerals of the ‘kaolinite’ group having 1:1 n in Figure 2. The

the clay minerals of the ontmorillonite’ and the

derived from the tures of the 2:1 layer

g more or less e octahedral

dral sheet in the crystal tructur

on the first part of the double layer, i.e., the negative charge on the surface

his concept of composite layers is known

otential between the fixed part of the rtion of the

ouble layer is termed as zeta potential (ζ).

ace, with The charge

of clay. Kaolinite is the commonest example of 1:1 clay minerals, where

ontmorillonite represents 1mminerals. A diagrammstructures of both the kalayer is shown in Figure 1.

A schemaatom arrangemmilayer structure is show‘unit cell’ of‘smectite’ or ‘m‘illite’ groups are prototypes of the struc(Figure 3) by introducinrandom atom substitutions in thand/or tetrahes e. Zeta potential of clay

If two phases of different chemical composition are in contact, an electric potential difference develops between them. This potential difference is accompanied by a charge separation, one side of the interface being positively charged and the other being negatively charged. When clay particles are suspended in water, the exchangeable cations of the clay would be solvated and ionized. The OH- ions from the water would also get adsorbed at the broken bonds of the clay lattice. These would make the clay surface negatively charged. The negatively charged surface would attract some cations in its vicinity (Figure 4). At equilibrium, therefore, an electrical double layer would exist at the particle-liquid interface. One part of the double layer consists of a negatively charged layer on the surface of the clay particle and the second part of the double layer in the aqueous phase comprises ions with overall positive charge predominance.

of the clay particle remains always fixed. The charge on the other side of the double layer, i.e., the solution side containing the counter ions (cations in the case of clay suspension) can be divided into two parts – a fixed part of the counter ions at a distance from the clay surface and another diffuse (or mobile) portion of counter ions with concentration gradually falling off or rising to that prevailing in the bulk of the aqueous phase. T

as Stern’s double layer concept. Because of the charge distribution in the electrical double layer, a sharp drop of potential exists from the negatively charged clay surface to the positively charged fixed part of the double layer on the aqueous phase side. It is then followed by a gradual change in potential across the diffuse part up to the bulk of the solution. The total potential drop from the solid clay surface to the bulk of the solution is called the double layer potential (ψ). The difference in pcounter ions and the diffuse pod

When clay particles are suspended in water, the system may be considered as a spherical condenser, with two concentric charged plates (Figure 5). If ‘e’ is the amount of the effective electrical charge on the particle, ‘d’ is the effective distance between the fixed positive and negative layers, and ‘D’ is the dielectric constant of the surrounding liquid (water), then the zeta potential (ζ) of the system is given by –

)1(......................4Dedπζ =


Figure 1: Diagrammatic sketch of the

ure of kaolinite (A) and smectite (B) struct



Figure 2: Atom arrangement in the unit cell of a 1:1 layer mineral (schematic)

Figure 3: Atom arrangement in the unit cell of a 2:1 layer mineral (schematic)

The zeta potential is very important in determining the properties of colloidal clay suspensions, particularly the suspension

stability, flocculation and deflocculation, effect of cations etc. The stability of clay suspension can be explained by DLVO theory (developed by B. Derajaguin & L.




J. T. G. Overbeek). Accbalance be

and the attractivVan der Waals interactionmolecules in the particVrepulsion > Vbecomedeflocculated systemVrepulsion < Vattractof particlesflocculatedinteractionsdirectly related to system. By addition of cations or bulky nions, the zeta potential (ζ) and thereby

the Vrepulsiosulting in flocculation or deflocculation of

the clay suspension. The concept of zeta potential is applied in selective separation of minerals. This concept is also utilized in processing of fine particles of various origins like coal, graphite, clay, limestone, chalcopyrite, hematite etc. by the technique of ‘froth floatation’. The knowledge of zeta potential is also very much important in respect of application of these materials, e.g., clay minerals in drilling muds, ceramics, paper, plastics, polymers, insecticide/pesticides, cosmetics etc.

The zeta potential (ζ) of solid suspension is highly depended upon the potential determining ions H+ or OH-. On changing the pH of the suspension the surface may become positive or negative due to interaction with H+ or OH- ions. At a certain pH majority of surface sites of a material may become neutral and the zeta potential of the mpH is kn

Landau and independently by E. Verwey and ording to it there is a

tween the repulsive interactions between the charges of the electrical double layer on neighbouring particles (Vrepulsion)

e interactions arising from s between the

les (Vattraction). When attraction,, the clay suspension

s a stable dispersion or a . Whereas when

ion,, because of aggregation the clay suspension becomes a system. The repulsive between the particles are

the zeta potential (ζ) of the

aof the system can be controlled, n

re

Figure 4: A schematic representation of the structure of electrical double layer (Stern’s double layer)

The zeta potential (ζ) of clay depends upon various factors like structural defects, isomorphous substitution, cation exchange capacity, presence of adsorbed impurities, coatings of other materials etc. Removal of impurities from the clay would, therefore, alter its zeta potential.

The zeta potential (ζ) can be determined by measuring the mobility of the fine particles in an applied electric field. The mobility of the fine particle can be converted to zeta potential using Smoluchowski equation –

aterial become zero. This own as a point of zero charge or

isoelectric point (iep). Each material is characterized by its own iep.

πηκαζεπε 6/1(4 0 + )μ = rE

εo and εr are the relative dielectric constant and where, μE is the particle mobility,

relative permittivity of vacuum respectively, η is the fluid phase viscosity, a is the particle radius and κ is the Debye-Huckel parameter.


Figure 5. Distribution of charges and the electrical double layer on a colloidal particle of clay suspended in water Zeta potential analyses

The zeta potentials of the various clay fractions of Deopani kaolin were evaluated with the help of Zetasizer 3000 HS attached with autotitrator MPT 1 (Malvern Instruments, UK). The zeta potential was measured by the technique of electrophoresis. The technique of electrophoresis involves measurement of the movement of particles when they are placed in an electric field. This method gives the value of mobility of particles which is related to the zeta potential.

For some samples, zeta potential was determined by single point zeta potential determ

le point zeta otential determination washed and are

prepared under similar conditions and are comparable. For evaluation of variation of

zeta potential with respect to pH, a requisite amount of clay was suspended in distilled water with vigorous stirring and the pH of suspension was adjusted to ~ 6.0. The suspension was then centrifuged (11500 rpm, 15 min, Centrifuge model R24, make Remi, India) and the clear supernatant decanted off. The process of addition of distilled water, stirring, centrifugation and decantation of the clear supernatant were continued till all the soluble matter content was washed off as indicated by the pH and conductivity of the supernatant (supernatant pH and conductivity at this point was very near to that of the used distilled water). Before zeta potential measurement the clay suspension was ultrasonicated for about 3 min at 35 kHz with a sonicator (Julabo USR 3, Germany). The zeta potential of the clay particles in the suspension was measured at room temperature conditions (30 ± 2 oC).

TiO2 contents of the sample

ensity Magnetic Separator

bearing minerals. XRD ti

portion contains siderite and ilmenite as the

Zeta potential of some fractions of Deopani clay

The ζ potentials of some oxalic acid leached fractions along with as such – 53 μm fraction clay, its – 4 μm fraction, nonmagnetic and magnetic portions as determined by the method of single point zeta potential determination are shown in Table 1. The Fe


ination, which gives the zeta potential value of a material at a particular condition of pH, ionic concentration etc. In case of few samples, the variation of zeta potential with respect to pH was evaluated by using the auto titrator attached with the zeta potential analyzer.

For the single point zeta potential determination, the samples after fractionation or separation by various physico-chemical methods were utilized. All the samples used for singp

2O and3s and the pH of the suspensions (6.0 ±

0.3) used for ζ potential measurement are also indicated.

The magnetic portion, separated from the as such – 53 μm fraction clay by Wet High Int(WHIMS) treatment, contains high amount of iron and titaniuminvestiga on showed that the crude clay contains siderite as the major iron bearing mineral with goethite/hematite and pyrite as the other iron bearing mineral and ilmenite as the titaniferrous mineral. The XRD pattern also indicated that the magnetic



nerals.

g of the

t

ects and s.

) of

gnetic

easurement. The wer iron and titanium content of the

the as such – 53 m fraction clay indicate that the

nonma

due to the accumu

als, therefore, results in the d

on nd dissociation of the exchangeable cations,

geneous splitting of the – Si – O – Al O - bonds etc. are responsible for this.

Howev

D of the suspension medium (in this

major iron and titanium bearing miThe SEM-EDXA investigation showed that apart from being present as discrete particles, the iron and titanium bearinminerals are also present as coatingsclay particles. It is very much possible thathese naturally occurring iron and titanium bearing minerals have structural defstructural & adsorbed anionic impuritieDue to this, the isoelectric points (iepthese minerals are possibly shifted to low pH values. The ζ potential value of the maportion, containing high amount of iron and titanium, is found to be highly negative (- 36.7 mV) at the pH of mlononmagnetic portion thanμ

gnetic portion obtained after removal of the magnetic portion is partially free from the iron and titanium bearing minerals. The ζ potential value of the nonmagnetic portion, therefore, decreases from that of the – 53 μm fraction clay due to removal of the iron and titanium bearing minerals having high negative ζ potential value.

Although the iron content of the fine fraction separated from the untreated – 53 μm fraction clay decreases, the titanium content increases, possibly

lation of titanium bearing minerals in the finer fraction. The ζ potential value of the untreated fine fraction is found to be higher than that of the – 53 μm fraction clay.

On leaching with oxalic acid, the iron and titanium content of the fine fraction decreases with increase in acid concentration. The removal of the iron and titanium bearing miner

ecrease of the ζ potential value of the fine fraction with increasing oxalic acid concentration.

The iron content of the three oxalic acid leached fractions increases in the order: fine < medium < coarse. Consequently, the ζ potential value of these fractions increases in the order: fine < medium < coarse.

Figures 6 shows the variation of zeta potential with pH in oxalic acid leached (Fe2O3: Oxalic acid mol ratio = 1.0:1.0) fine (- 4 μm) and medium (- 10 μm + 4 μm) fractions of the clay. The samples used for this experiment were prepared under similar conditions and were washed completely free of all soluble matters. The trend line of the zeta potential was drawn by using a polynomial equation of 3rd degree chosen automatically by the software used (Microsoft Excel 2002 version 10.2614.2625). The correlation factors (R2) shown on the graph indicate that the trend of ζ potential is well fitted with the experimental points.

Clay particles when suspended in water develop two types of charges, negative charges on its surfaces and positive charges on its edges. Various factors like isomorphic substitution in clay crystal lattice, hydratiasplitting of clay crystals / particles, hetero–

er, the effective charges on clay particles are always negative because the amount of negative charges developed due to isomorphic substitution in octahedral sites of clay crystal lattice is always higher than the amount of positive charges developed due to other reasons. Consequently, the clay particles always show negative ζ potential value. For a particular system of clay suspension, the

case water) is constant and the ζ potential value depends on e and d (cf. equation 1).

At acidic pH range (pH < 7.0), the clay particles will adsorb H+ ions at the negatively charged sites resulting in decrease in the e. The exchangeable cations will also be replaced by the H+ ions. The size of the H+ ions and its hydration sphere is small. The e/r ratio (e = charge on the hydrated ionic sphere and r = radius of the hydrated ion) of the H+ ions is high. As a result the



alic acid leached finer fr

concen

rease in e (effective surface charge

adsorpt

attraction between the negatively and positively charged layers of the electrical double layer of the clay particle in suspension increases. The thickness of the electrical double layer (d) of H+ exchanged clay particle, therefore, reduces resulting in decreased ζ potential at acidic pH range.

At alkaline pH range (pH > 7.0), the clay particle adsorbs OH- ions at the positively charged sites (edges). The effective surface charge density (e) of the clay particles consequently increases. The OH- ions are also adsorbed on the surfaces of the clay particles and as there size is very big (e/r ratio low), the thickness of the electrical double layer (d) of the clay particles increases in presence of OH- ions. The ζ potential value of the clay particles, therefore, increases at alkaline pH range.

Figure 6 show that the clay particles have negative ζ potential value throughout the entire pH range of measurement (2 to 10). The iso electric point (iep), i.e., the point of zero charge was never attained and it may be below pH 2.0. At all pH level, the ζ potential value of the ox

action (- 4 μm) having lower Fe2O3 content (0.95 %) is lower than that of the oxalic acid leached medium fraction (- 10 μm + 4 μm) having higher Fe2O3 content (1.30 %). The trend of variation of the ζ potential with pH in both the fraction is similar. In the acidic range (pH < 7.0), with decrease in pH (increasing H+ ion

tration), the ζ potential value decreases due to progressive decrease in e (effective surface charge density) and d (thickness of electrical double layer). In the alkaline range (pH > 7.0), with the increase in pH (increasing OH- ion concentration), the ζ potential value increases due to progressive inc

density) and d (thickness of electrical double layer). The ζ potential value, in both the cases, attains a constant value at a pH of about 9.08, indicating that no further

ions of OH- ions are taking place and all adsorption sites are saturated.

R2 = 0.9938

-60

-50

-40

-30

-20

-10

0

10

0 1 2 3 4 5 6 7 8 9 10

pH

Zeta

pot

entia

l (m

V)

R2 = 0.9819

Oxalic acid leached f ine fractionOxalic acid leached medium fraction

Figure 6: Influence of pH on the zeta potential (ζ) of oxalic acid leached fine (- 4 μm) and medium (- 10 μm + 4 μm) fractions. Conclusion The ξ potential of the iron and titanium bearing magnetic materials present as contaminants in Deopani clay is highly negative. Removal of these materials from the clay either by oxalic acid leaching or by WHIMS treatment decreases the ξ potential of the clay. The kaolinite fraction, as expected, showed negative ξ potential. The removal of the iron and titanium bearing minerals with increasing oxalic acid concentration results in the decrease of the ξ potential value of the fine fraction. The iron content of the three oxalic acid leached fractions increases in the order: fine < medium <coarse. Consequently, the ξ potential value of these fractions increases in the order: fine < medium < coarse. The ξ



xali

c

Fe2O3 content

(%)

TiO2 content

(%)

Suspension p

Table 1. Zeta potential values (ξ ) of the o

Sl. no.

Clay sample Fe

c acid leached fraction of Deopani clay

2O3: Oxaliacid (M)

H ζ (mV)

1 As such – 53 μm clay 0.0:0.0 2.86 0.90 5.8 - 27.8

2 Nonmagnetic portion of as such clay

0.0:0.0 1.10 0.70 5.7 - 21.7

3 Magnetic portion of as such clay

0.0:0.0 20.94 8.13 6.3 - 36.7

4 Fine fraction of the as such untreated clay

0.0:0.0 2.17 1.01 6.2 - 29.9

5 Fine fraction of the oxalic acid treated clay

1.0:0.2 1.17 0.66 6.2 - 25.7

6 - do - 1.0:1.0 0.95 0.51 5.9 - 22.7

7 Medium fraction of the oxalic acid treated clay

1.0:1.0 1.30 - 6.3 - 25.9

8 Coarse fraction of the oxalic acid treated clay

1.0:1.0 2.09 - 6.2 - 29.9

Coarse: – 53 μm + 10 μm, Medium: – 10 μm + 4 μmShearing time: 12 hours; Leaching temperature: roo

potential value of the medium and fine fractions increases with increase in pH of the suspension due to adsorption of OH

, Fine 4 μm.; Shearing rate: high ~ 14000 rpm; m tem

436.

1995. Reducing the iron content of kaolin from Milos, Greece, by a hydrometullurgical process. Trans. Inst.

: – perature (28 ± 4 oC).

2. Veglio, F., Pagliarini, A. and Toro, L., 1993. Factorial experiments for the development of a kaolin bleaching process. Int. J. of Miner. Process., 39, pp 87-99.

3. Bhatt, J. V., 1998. Opportunities for value added china clay projects in Gujarat. Report of Industrial Extension Bureau, Govt. of Gujarat, Ahmedabad, India. pp 27-32.

4. Theng, B. K. G., 1974. Chemistry of clay organic reactions. John Wiley & Sons, New York. pp 1-3, 198-206, 261-291.

5. Tsimus, S. G., Komiotou, M. A., Moutsatson, A. K. and Parrisakis, G. K.,

- ions and attains a constant value (– 58.5 and - 53.9 mV respectively) at a pH of about 9.08, indicating that no further adsorptions of OH- ions takes place and all adsorption sites are saturated beyond this pH. The iso electric point (iep) of the clay fractions possibly lies below pH 2.0 and could not be determined. References and further readings 1. Searle, A. B. and Grimshaw, R. W.,

1960. The Chemistry and Physics of Clays and Other Ceramic Materials. 3rd ed., Ernest Benn Limited, London, pp 100-104, 126-143, 273, 280, 292-293,



MExtr. Metal.), 104, May-August 1995, pp C -C114

6. S kova, I., Styriak, I., NandakM. P. and Mattiasson, B., 2003. Bacterial destruction of mica during bioleaching of kaolin and quartz sands by Bacereus. World J. of Microbiology & Biotechnology, 19, pp 583-590.

7. Styriakova, I., Styriak, I., Malachovsky, P. and Lovas, M., 2006. Biological, chemical and electromagnetic treatment of ateriaM ner.

8. Worrall, W. E., 1982. Ceramic raw materia nstitutCeramics Textbook Series, Pergamon P ss Ltd., Oxf p 5, 14-17, 262.

9. Grim, R eraloged., International Series in the Earth and Planetary Sciences, McGraw-Hill Book Comp 0, 557-79.

10.

Delhi, pp

15.

tems. Chem. Rev., 65, pp 177-198.

smulski, M., 2004. pH-dependent ac ing and points of zero

arge pdate. J. of Colloid and Interface Science. 275, pp 214-224.

1 unter J., 198 nd printing. Zeta tenti Coll Princ

Press, London, ch. 3, p 69.

Short biography of the author: Mr. Pinaki Sengupta is sently ntist F and is the Head of the Materials Science D n, Nort ast In e of Science and Technology, Jorhat 785 006, Assam. He has 26 years R & D experience i e ar f oil chem and materials, ores and minerals, building materials, environmental issues related to oil fields; Completed several projects for OIL Duliajan, ONGCL, CMPDIL Ranchi, Min. of Mines, Min. of Environment &

ers of e Indian Institute of

EngConof Com for Burnt Clay Products, CED

conDriCla---- 00---------------------

----

in. Metall. (Sect. C: min. Process. aqueous hydroxo complex sys

110tyria

. umar,

cillus

three typi

es of feldspar raw m Eng., 19, pp 348-354.

ls,

ls, 2nd rev. ed., I e of

re ord, p 6-33,

. E., 1968. Clay min y, 2nd

any, New York, pp18-3 1-52,

Van Olphen, H., 1977. An introduction to clay colloid chemistry, John Wiley & various societies likSons, New York, pp 57-70.

11. Rakshit, P. C., 1973. Physical Chemistry. 3rd ed., Science book Agency, Calcutta, pp 622-624.

12. Castellan, G. W., 1994. Physical Chemistry. 3rd ed. (14th reprint), Narosa publishing House, New Delhi, pp 432-438

13. Atkins, P. and Paula, J. de, 2006. Atkin’s Physical Chemistry. 1st Indian ed.,Oxford University Press, New 682-685.

14. Kosmulski, M., 2001. Chemical Properties of Material Surfaces. Marcel Dekker, New York. Parks, G. A., 1965. The isoelectric poins of solid oxides, solid hydroxides, and

16. Kosurfch

e chargII. U

7. H , R. 6. 2PoApplications. Academ

al in oid: ic

iples and

pre Scie

ivisio h-E stitut

n th eas o field icals

Forests etc. Mr. Sengupta is memb

Mineral Engineers, Society of Petroleum ineers (USA), Indian Science gress, Assam Science Society, Bureau

Indian Standard: Specification mittee

30. In 1990-1991 he visited and ducted research in Institute of Deep lling Technology, Technical Unversity usthal, Germany. -----------------0

Albert Einstein “An empty stomach is not a good political adviser.”

-----------------000---------------------


Article section


Green Clean: A Hope

. Nabanita Bhattacharyya [email protected]

Msmsn

Biology in modified form of technology is one of the most important ntific and technological revolutions of

last

Biosciethe century and has greatly benefited

alreheaenvdev ts in this important area provide

envsus ow, it is time

‘gre‘ph n’- defined by a novel

by of ever increasing global problem

altemeoccurs naturally in ecosystems as both

andme iddle of the 20th

repItalian serpentine plant Alyssum bertolonii.

thatcon

here

and industrial by-

i d maintenance compared to methods. For example, thesandy loam plants esti 0,000

Phytoremediation is a wide concept involves several ways to clean up tamination by plants, such as-

► Phytovolatilization, where plants take up water and organic contaminants through the roots, transport them to the leaves and release the contaminants as a reduced form of detoxified vapor into the atmosphere.

► Microorganism stimulation, worganic substances and enzymes exerted by the plant roots stimulate the growth of some fungi and bacteria in their root zone and those microbes in turn metabolize the organic contaminants.

► Phytostabilization, where plants prevent contaminants to migrate laterally by reducing run off, surface erosion, and ground water flow rates.

► Phytoaccumulation or Phytoextraction, where plant roots take up metals from contaminated sites and accumulate them in aerial parts like leaves and stems.

► Phytodegradation, where plants absorb organic contaminants and break down (metabolize) them into non-toxic molecules by biochemical processes within the plant body.

Currently phytoremediation technology is being used to clear off various polluting elements such as heavy metals, insecticides, petro-products, explosives, chlorinated solvents

various aspects of human life. The potentials are enormous and many breakthroughs have

ady been achieved in the area of lthcare, food, agriculture products, ironmental pollution etc. The elopmen

immediate benefits to mankind and offer ironmental friendly technologies for tainable development. And n

for ‘biological cleaning’ popularly known as en clean’ and scientifically termed as

ytoremediatiostrategy for the removal of toxic inorganic or organic contaminants from the environment

plants. Like all other biological solutions s, the

concept of phytoremediation or green clean is also cost effective and user friendly

rnative to traditional remediation thods. In fact, this is an old process that

products. The major advantage ofphytoremediation technology is the low cost

mplementation another treatment

and ease of inorganic and organic constituents of soil

water cycle through plants. However, n could realize it in the m

cost of cleaning up one acre of soil at a depth of 50 cm with mated at $60,000-$10century when some Italian researchers first

orted nickel hyper accumulation in the compared to $400,000 for the conventional excavation and disposal method. Besides, it



is an aesthetically pleasing mechanismpublic, which can be implemented in

ell as ex situ conditions. tage of this

ethods, which poses a

arket place. This challenge should be faced jointly by

ental engineers and prove the technology’s efficacy

ajor concern with hytoremediation is the possible effects on

ed to absorb te toxins and are

aten by th

ecently, Richard Meagher at the ty of Georgia (Athens) by inserting

an altered mercury ion reductase gene (mer A) int

Results to

physoilcost of other traditional engineering mettrea hemical extraction (Rai et

GovdevtechEnvLia as

reseresedev ytoremediation

undthe phy200

technologies as part of living culture, ecoundclea s for increased societa

to the situ as

plants. RUniversi

wo Arabidopsis thaliana, produced

mercury resistant transgenic mer A plants which are soon to be tested in soil.

Major disadvanechanism is the slower rate of clean upm

than conventional mgreat challenge in the m

scientists, environmregulators toat pilot sites.

Another m

date suggest that the cost of toremediation of mercury contaminated s will be one-tenth to one-hundredth the

hods, including land filling, thermal tments and c

al, 1999). During the 1980s, the US ernment initiated a large program for the

elopment of environmental clean up nologies (The Comprehensive ironmental Response, Compensation and

bility Act or Superfund), which h

pthe food chain as vegetation usthe toxic elements accumulae e moles or voles, which in turn are eaten by the predators. Hence, there may be a continuous chain of victims of intoxication that may lead to a threat like biological magnification. More field work and analysis is necessary to understand such dangerous effects of phytoremediation and this may prove as a major research area in near future.

Despite certain short comings, many forms of phytoremediations have emerged from the laboratories and are currently in practice and public acceptance is very encouraging. For instance, this strategy has already been successfully implemented by the US Air Force to clean trichloroethylene from ground water using poplar trees and by the US Army to clean 2,4,6-trinitrotolune (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) from contaminated wetlands using variety of plants. In India, aquatic vascular plants like Hydrilla verticillata, Spirodela polyrrhiza, Bacopa monnierii, Phragmites karka and Scirpus lacustris have been used to treat chromium contaminated effluent and sludge from leather tanning industries.

Two routs are currently being explored to improve the efficiency of contaminant accumulating plants: genetic engineering and the selective breeding of naturally occurring hyper-accumulator

accelerated the growth of a new productive arch field worldwide. As a result, archers have come to learn that the elopment of ph

technologies requires a thorough erstanding of the underlying processes at

genetic, molecular, biochemical, siological and agronomic levels (Kramer, 5).

By employing the phytoremediation

logical systems, we can bring our erstanding and appreciation of green n into sharper focu

l benefits. References: 1. Rai UN and Pal A (1999). Toxic metal

and phytoremediation; Archives of Enviro News (Newsletters of International Society of Environmental Botanists, India): Vol. 5, No. 4.

2. Kramer U (2005). Phytoremediation: novel approaches to cleaning up polluted soils. Current Opinion in Biotechnology, 16: 133-141.



ma. Later, she has joined as a

About the Author: Ms N. Bhattacharyya has received her B.Sc. from Nalbari College and M.Sc. in Botany (Advanced Plant Physiology and Biochemistry) from Gauhati University, Assam in 2000. After her M.Sc., she had joined in the Department of Biotechnology, Gauhati University to pursue her Ph.D under the guidance of Prof. S. SarLecturer in the Department of Botany, Nowgong College, Assam. Her current research interests include Plant Physiology, Biochemistry and Environmental Biotechnology. ---------------------000--------------------- Positron Emission Tomography

Dr. Diganta Sarma [email protected] Introduction

Positron emission tomography (PET) is a particularly powerful non-invasive method for molecular imaging in living systems, including the brain, the heart, and other active tissues and organs. A positron emitting radionuclide is incorporated into a PET tra

r that reconstructs the spatial distribu

PET studies are N, O, nd F, which have half-lives of 9.96, 2.07,

n, respectively. Because of the

emivivcomlow r), far

pha Problems in synthesizing PET tracers

The short life (several minutes to urs) of positron emitting radionuclides

cer as an efficient molecular probe to monitor the dynamic behavior of the corresponding non-radioactive compound, as well as to localize its target molecules

involved in biochemical processes and biofunctions in vital systems. The need to develop new PET tracers has grown with the increase in use of this technique in biochemistry, medicine, and drug development. Principle

The principle of PET imaging using 11C as a representative radionuclide is illustrated in Fig. 1. 11C undergoes β+ decay with a half-life of 20.3 min as a result of conversion of a proton into a neutron and an emitted positron (e+), yielding 11B as the stable nuclide. The positron ejected by this process has a range of a few millimeters in tissue and is annihilated by collision with an electron, producing two high energy γ-ray photons of 511 keV each. These photons travel in opposite directions, penetrating the body, and can be detected by a pair of opposing scintillation detectors. If two opposite detectors are hit simultaneously, it is assumed that the photons come from the same decay event. The data are fed to a compute

tion of the decay events produced. The fate of a 11C-incorporated compound can be imaged quantitatively with high sensitivity and high spatial resolution. The other commonly used positron-emitting radionuclides for 13 15

18aand 109.7 mireally high specific radioactivity of positron-

tter labeled compounds, PET enables in o imaging at extremely small mass of the pound (sub-femtomol) and at extremely concentrations (sub-picomola

below the critical concentration of rmacological effects.

ho



safer than X-ray e Tl(tritium5used in humptem P ra ncp th(e.g., the synthesis ofsTradionuclide produced by the synchrotron as

11

l reaction. Another difficulty ncountered in PET-tracer synthesis is the

of tiny amounts of precursor, quiring the use of an extremely dilute

solution

makes PET imaging organic framework; work-up and chromatographic purification of the tracer; and, administration of the tracer to humans. Thus, the time allowed for tracer synthesis should be only about 5–10 min, necessitating a rapid chemica

xamination in terms of radiation exposure.his is in marked contrast to commonly used

ong lived radionuclides, including 3H ) and 14C, with half-lives of 12.3 and

730 years, respectively, which cannot be ans. However, the short-life of

ositron emitting radionuclides places a poral restriction on the preparation of

ET trace s. In general, the total time llowed for PET-tracer synthesis, i luding urification should be within two- o-three alf-lives of the corresponding radionuclide

a

eavailabilityre

(of the order of pM–µM) of the reaction mixture, much lower than those used in normal organic reactions mM–M. In addition, the efficient purification of a small amount of synthesized tracer from large amounts of remaining precursors must also be considered. These severe demands on PET-tracer synthesis have limited

11C-labeled tracer hould be accomplished within 40–60 min). his should include: derivatization of the

11CH3 incorporation to N- and O-methylations. an appropriate precursor, such as CH I, 3

11CO, or 11CO ; incorporation of 11C into an2


Common Uses Thermo Responsive Magnetic Nanoparticles and their Applications

PET scans are performed to (1) detect cancer (2) determine the how much a cancer has spread in the body (3) assess the effectiveness of a treatment plan, such as cancer therapy (3) determine if a cancer has returned after treatment (4) determine blood flow to the heart muscle (5) determine the effects of a heart attack, or

myocardial infarction, on areas of the heart (6) identify areas of the heart muscle that would benefit from a procedure such as

angioplasty or Dr. Smriti R. Deka coronary artery bypass surgery (in combination with a

[email protected] perfusion

scan

) (7) evaluate brain abnormalities, such as tumors, memory disorders and seizures and other central nervous system disorders and (8) to map normal human brain and heart function.

Introduction

Magnetic materials are key component in modern technology, with applications ranging from data storage to magnetic resonance contrast agents. The unique size dependent properties of magnetic nanoparticles lead to a growing interest in nanostructural magnetic materials, composites and dispersions. Colloidal magnetic dispersions, known as magnetic fluids or ferrofluids, usually contain magnetic particles in the range from 10-20 nm. They behave as liquids whose physical properties and flow behaviours can be controlled by external magnetic field. The particles in ferrofluids are coated with layers of surfactants to enable stabilization against gravitation force and to avoid strong interaction and agglomeration of the particles. The magnetic heatability of the particles is an additional feature; the ability of ferrofluid to convert magnetic energy into heat.

Future Perspectives

PET imaging has seen truly exciting advances in recent years. Not only can technological advances create new and better ways to extract information about our bodies, but they also offer the promise of making some existing imaging tools more convenient and economical.

About the author: Diganta Sarma was born and brought up in Naharani of Golaghat District, Assam. After completing his M.Sc. degree (2000) from the Department of Chemistry, Gauhati University, he moved to National Chemical Laboratory, Pune to pursue his Ph.D. degree. Currently, he is working as a post doctoral research fellow (JSPS) in the Department of Medicinal Chemistry, Kyoto Pharmaceutical University, Kyoto, Japan.

Magnetic fluids are of high interest for basic research as well as for various applications. Novel properties of ferrofluid suitable for biological applications, such as solubility in physiological fluids and biocompatibility are important.

---------------------000---------------------


http://www.radiologyinfo.org/en/glossary/glossary1.cfm?term=myocard_infarction

http://www.radiologyinfo.org/en/glossary/glossary1.cfm?term=myocard_infarction

http://www.radiologyinfo.org/en/glossary/glossary1.cfm?term=angioplasty

http://www.radiologyinfo.org/en/glossary/glossary1.cfm?term=coronary_bypass

http://www.radiologyinfo.org/en/glossary/glossary1.cfm?term=myocard_perf_scan

http://www.radiologyinfo.org/en/glossary/glossary1.cfm?term=myocard_perf_scan

mailto:[email protected]



In current research, much respect is paid to the combination of such particles with stimuli responsive polymers to benefit from their materials properties or the presence of functional group along the polymer chain to receive organic-inorganic nanocomposits. Stimuli-responsive materials show a sharp change in properties upon a small or minor change in environmental condition, e.g. temperature, light, salt concentration, electric and magnetic field or pH. Thus, combining the stimuli-responsive “smart” behaviour with the properties of magnetic nanoparticles is an effective approach to fabricate a drug carrier. Thermoresponsive magnetic colloids are characterized by a coupled magnetoresponsive and thermoresponsive behaviour by the combination of magnetic nanoparticles with a suitable polymer system.

What are Thermo-responsive polymers?

Temperature-responsive polymers and hydrogels exhibit a volume phase transition at a certain temperature; this causes a sudden change in the solvation state. Polymers, which become insoluble upon heating, have a so-called lower critical solution temperature (LCST). Systems, which become soluble upon heating, have an upper critical solution temperature (UCST). Poly(N-isopropyl acrylamide) is one of the most important thermo-responsive polymer. It has a lower critical solution temperature (LCST) of 32 0C in water. It collapses and shrinks above LCST and swells and expands below the LCST. Due to its well-defined and reversible low critical solubility temperature PNIPAM has long been investigated as a versatile tool in biology. Water-based thermoresponsive microgels show a high application potential for controlled drug delivery. PNIPAM copolymers have been mainly studied for the oral delivery of calcitonin and insulin.

Synthesis of Magnetic Colloids with thermoresponsive polymers

There are different methods for synthesis of magnetic core-shell polymer nanoparticles coated with stimuli responsive polymers. But a straightforward strategy for the synthesis of polymer-coated inorganic nanoparticles is the grafting from approach or so called surface initiated polymerization. Surface-initiated polymerization is a relatively new pathway for the preparation of functional coatings, which can be achieved by different method, such as

Living ring opening polymerization Living anionic polymerization Living cationic polymerization Ring opening metathesis

polymerization (ROMP) Nitroxide-mediated radical

polymerization (NMRP) Reversible addition-fragmentation

chain transfer (RAFT) polymerization

Atom transfer radical polymerization (ATRP)

But the most popular strategy is the

ATRP due to tolerance to a wide range of monomers, flexible experimental conditions, etc. The technique is based on the growth of polymer molecules at the surface of a substrate in situ from surface-bound initiators and results in a irreversibly attached, covalently bound polymeric shell. Consequently, covalently anchored end-tethered polymeric chains with a high grafting density on the particle surface are formed. The approach offers the opportunity to form single-cored core-shell nanoparticles. A high potential for applications of magnetic fluids based on iron oxides is promised in the biomedical field.

The general scheme for synthesis of magnetic polymer brush particle is shown in scheme-1. First step consists of synthesis of magnetic nano particles by co-precipitation,


Applications

Thus the combination of magnetic nanoparticles with thermoresponsive polymer systems leads to the formation of hybrid particle dispersions or composites with a variety of interesting properties and perspectives, including instant dispensability, thermoreversible formation of magnetic fluids, and novel magnetoresponsive properties. Special interest is gained by the magnetic heatability of magnetic particles that allows the activation of thermal effects by the application of a high-frequency electromagnetic field. The concept of magnetic targeting is to inject magnetic nanoparticles to which drug molecules are attached, to guide these particles to a chosen site under the localized magnetic field gradients, hold them there until the therapy is complete, and then to remove them. The magnetic drug carriers have the potential to carry a large dose of drug to achieve high local concentration, and avoid toxicity and other adverse side effects arising from high drug doses in other parts of the organism.

Scheme-1

in the second step the surface of the particle can be modified by different functional group such as carboxyl group and finally magnetic core polymer brushes synthesized by polymerization with a thermoresponsive monomer.

By the combination of superparamagnetic nanoparticles with thermoresponsive polymers, the hybrid materials show the typical response of the particles to magnetic fields and the temperature responsive properties (Fig: 1) of the polymer are maintained and can be used to manipulate the material properties by conventional heating. On the other hand, temperature responsive properties of the polymer are maintained and can be used to manipulate the material properties by conventional heating.

Another interesting application of magnetic nanoparticles is in hyperthermia treatment which is considered as a supplementary treatment to chemotherapy, radiotherapy, and surgery in cancer therapy. The idea of using magnetic induction hyperthermia is based on the fact that when magnetic nanoparticles are exposed to a varying magnetic field, heat is generated by the magnetic hysteresis loss. Thus, when a magnetic fluid is exposed to an alternating magnetic field the particles become powerful heat sources, destroying tumor cells since these cells are more sensitive to temperatures. The amount of heat generated by magnetic nanoparticles depends strongly on the structural properties of the particles (e.g., size, shape) and should be as high as possible to reduce the dose to a minimum level. Such magnetic nanoparticles can also

Figure 1. Schematic behaviour of polymer brush particles in thermoreversible magnetic fluids a) temperature dependent behaviour, b) the particles precipitates below critical temperature and particle dispersion is formed above critical temperature under the influence of an external magnet.



be very useful to assist an effective separation of catalysts, nuclear waste, biochemical products etc. Summary

Stimuli-responsive polymers offer great advantages in drug delivery. Instead of acting passively as pure drug carriers, they will interact and respond to the environmental settings. This allows us to aim further for tailor-made drug delivery with superior pharmacokinenetics while having all safely questioned addressed.


About the Author: Dr. Smriti Rekha (Baruah) Deka hails from Jorhat, Assam. She received her B. Sc. degree from J. B. College, Jorhat and M. Sc. degree from the department of Chemistry, Gauhati University, Guwahati. She carried out her Ph. D. research in the same department and obtained her doctorate degree in 2007. Currently she is a postdoc fellow at the National Nanotechnology Laboratory of CNR-INFM-ISUFI, University of Lecce, Italy. ---------------------000--------------------- RNA interference(RNAi)

Mr. Khirud Gogoi [email protected]

RNA interference (RNAi) is a mechanism that inhibits gene expression at the stage of translation or by hindering the

transcription of specific genes. Small interfering RNA strands (siRNA) are key to the RNAi process, and have complementary nucleotide sequences to the targeted RNA strand. Specific RNAi pathway proteins are guided by the siRNA to the targeted messenger RNA (mRNA), where they "cleave" the target, breaking it down into smaller portions that can no longer be translated into protein. A type of RNA transcribed from the genome itself, microRNA (miRNA), works in the same way.

The RNAi pathway is initiated by the enzyme dicer, which cleaves long, dsRNA molecules into short fragments of 20-25 base pairs. One of the two strands of each fragment, known as the guide strand, is then incorporated into the RNA-induced silencing complex (RISC) and pairs with complementary sequences. The well-studied outcome of this recognition event is post-transcriptional gene silencing. This occurs when the guide strand specifically pairs with a mRNA molecule and induces the degradation by argonaute, the catalytic component of the RISC complex. Another outcome is epigenetic changes to a gene- histone modification and DNA methylation-affecting the degree the gene is transcribed.

The selective and robust effect of RNAi on gene expression makes it a valuable research tool, both in cell culture and in living organisms because synthetic dsRNA introduced into cells can induce suppression of specific genes of interest. RNAi may also be used for large-scale screens that systematically shut down each gene in the cell, which can help identify the components necessary for a particular cellular process or an event such as cell division. Exploitation of the pathway is also a promising tool in biotechnology and medicine. In 2006, Andrew Fire and Craig C. Mello shared the Nobel Prize in Physiology or Medicine for their work on



RNA interference in the nematode worm C. elegans, which they published in 1998. History and discovery

The discovery of RNAi was preceded first by observations of transcriptional inhibition by antisense RNA expressed in transgenic plants, and more directly by reports of unexpected outcomes in experiments performed by plant scientists in the U.S. and the Netherlands in the early 1990s. In an attempt to alter flower colors in petunias, researchers introduced additional copies of a gene encoding chalcone synthase, a key enzyme for flower pigmentation into petunia plants of normally pink or violet flower color. The overexpressed gene was expected to result in darker flowers, but instead produced less pigmented, fully or partially white flowers, indicating that the activity of chalcone synthase had been substantially decreased; in fact, both the endogenous genes and the transgenes were downregulated in the white flowers (Fig.1).


Figure 1. Petunia plants in which genes for pigmentation are silenced by RNAi. The left plant is wild-type; the right plants contain transgenes that induce suppression of both transgene and endogenous gene expression, giving rise to the unpigmented white areas of the flower.

Not long after, plant virologists working on improving plant resistance to viral diseases observed a similar unexpected phenomenon. While it was known that plants expressing virus-specific proteins showed enhanced tolerance or resistance to viral infection, it was not expected that plants

carrying only short, non-coding regions of viral RNA sequences would show similar levels of protection. Researchers believed that viral RNA produced by transgenes could also inhibit viral replication. The reverse experiment, in which short sequences of plant genes were introduced into viruses, showed that the targeted gene was suppressed in an infected plant. This phenomenon was labeled "virus-induced gene silencing" (VIGS), and the set of such phenomena were collectively called post transcriptional gene silencing.

After these initial observations in plants, many laboratories around the world searched for the occurrence of this phenomenon in other organisms. Craig C. Mello and Andrew Fire's 1998 Nature paper reported a potent gene silencing effect after injecting double stranded RNA into C. elegans. In investigating the regulation of muscle protein production, they observed that neither mRNA nor antisense RNA injections had an effect on protein production, but double-stranded RNA successfully silenced the targeted gene (Fig. 2). As a result of this work, they coined the term RNAi. Fire and Mello's discovery was

Figure 2. Phenotypic effect after injection of single-stranded or double-stranded UNC-22 RNA into the gonad of C. ELEGANS. The UNC-22 gene encodes a myofilament protein. Decrease in UNC-22 activity is known to produce severe twitching movements. Injected double-stranded RNA, but not single-stranded RNA, induced the twitching phenotype in the progeny.


particularly notable because it represented the first identification of the causative agent for the phenomenon. Fire and Mello were awarded the Nobel Prize in Physiology or Medicine in 2006 for their work.


Cellular mechanism

RNAi is an RNA-dependent gene silencing process that is controlled by the RNA-induced silencing complex (RISC) and is initiated by short double-stranded RNA molecules in a cell's cytoplasm, where they interact with the catalytic RISC component argonaute. When the dsRNA is exogenous (coming from infection by a virus with an RNA genome or laboratory manipulations), the RNA is imported directly into the cytoplasm and cleaved to short fragments by the enzyme dicer. The initiating dsRNA can also be endogenous (originating in the cell), as in pre-microRNAs expressed from RNA-coding genes in the genome. The primary transcripts from such genes are first processed to form the characteristic stem-loop structure of pre-miRNA in the nucleus, then exported to the cytoplasm to be cleaved by dicer (Fig. 3). Thus the two pathways for exogenous and endogenous dsRNA converge at the RISC complex, which mediates gene silencing effects.

Technological applications of RNAi Gene knockdown

The RNA interference pathway is often exploited in experimental biology to study the function of genes in cell culture and in vivo in model organisms. Double-stranded RNA is synthesized with a sequence complementary to a gene of interest and introduced into a cell or organism, where it is recognized as exogenous genetic material and activates the RNAi pathway. Using this mechanism, researchers can cause a drastic decrease in the expression of a targeted gene. Studying

the effects of this decrease can show the physiological role of the gene product. Since

Figure 3. The RNA interference process and the biochemical machinery involved. Double-stranded RNA is cut into short pieces (siRNA) by the endonuclease Dicer. The antisense strand is loaded into the RISC complex and links the complex to the mRNA strand by base-pairing. The RISC complex cuts the mRNA strand, and the mRNA is subsequently degraded. RNAi may not totally abolish expression of the gene, this technique is sometimes referred as a "knockdown", to distinguish it from "knockout" procedures in which expression of a gene is entirely eliminated. Most functional genomics applications of RNAi in animals have used C. elegans (Fig. 2) and Drosophila (Fig. 4), as these are the common model organisms in which RNAi is most effective. C. elegans is particularly useful for RNAi research for two reasons: firstly, the effects of the gene silencing are


generally heritable, and secondly because delivery of the dsRNA is extremely simple.


Figure 4. A normal adult Drosophila fly, a common model organism used in RNAi experim nts e Medicine

It may be possible to exploit RNA interference in therapy. Although it is difficult to introduce long dsRNA strands into mammalian cells due to the interferon response, the use of short interfering RNA mimics has been more successful. Among the first applications to reach clinical trials were in the treatment of macular degeneration and respiratory syncytial virus, RNAi has also been shown to be effective in the reversal of induced liver failure in mouse models.

Other proposed clinical uses center on antiviral therapies, including the inhibition of viral gene expression in cancerous cells, knockdown of host receptors and coreceptors for HIV, the silencing of hepatitis A and hepatitis B genes, silencing of influenza gene expression, and inhibition of measles viral replication. Otential treatments for neurodegenerative diseases have also been proposed, with particular attention being paid to the polyglutamine diseases such as Huntington's disease. RNA interference is also often seen as a promising way to treat cancer by silencing genes differentially upregulated in tumor cells or genes involved in cell division. A key area of research in the use of RNAi for clinical applications is the

development of a safe delivery method, which to date has involved mainly viral vector systems similar to those suggested for gene therapy.

Biotechnology

RNA interference has been used for applications in biotechnology, particularly in the engineering of food plants that produce lower levels of natural plant toxins. Such techniques take advantage of the stable and heritable RNAi phenotype in plant stocks. For example, cotton seeds are rich in dietary protein but naturally contain the toxic terpenoid product gossypol, making them unsuitable for human consumption. RNAi has been used to produce cotton stocks whose seeds contain reduced levels of delta-cadinene synthase, a key enzyme in gossypol production, without affecting the enzyme's production in other parts of the plant, where gossypol is important in preventing damage from plant pests. Similar efforts have been directed toward the reduction of the cyanogenic natural product linamarin in cassava plants.

Conclusions:

The discovery that cells have a special mechanism for suppressing the expression of homologous genes by recognizing and processing double-stranded RNA was totally unexpected and has dramatically expanded the knowledge of gene control. Remarkably, the RNAi machinery can handle double-stranded RNA entering the cell as well as double-stranded RNA generated within the cell. The development of an organism and proper function of its cells and tissues are dependent on an intact RNAi machinery. Infection by RNA viruses can be blocked by RNAi, especially in plants and lower animals, and foreign elements in the genome (viruses and transposons) can be kept silent. Finally, the discovery of RNAi has not only provided a powerful new experimental tool


to study the function of genes but also raises expectations about future applications of RNAi in medicine. References 1.Fire A., Xu S., Montgomery M., Kostas S., Driver S. and Mello C. (1998) Nature ,391 (6669): 806-11. 2. Daneholt, B. Advanced Information: RNA interference. The Nobel Prize in Physiology or Medicine 2006. 3. Elbashir S .M., Harborth, J., Lendeckel, W., Yalcin, A., Weber, K. and Tuschl, T . (2001) Nature, 411, 494-498. About The author Khirud Gogoi has recently completed Ph. D. from National Chemical Laboratory, Pune, India in the area of Nucleic Acids Chemistry. His areas of research include design and synthesis of novel oligonucleotides for therapeutics purpose, ribozymes and cellular delivery of siRNA. ---------------------000--------------------- Nanoscience and Nanotechnology for Improvement of Human Lives

Mr. Pankaj Bharali [email protected]

Nanoscience is the emerging science of objects that are intermediate in size between the largest molecules and the smallest structures that can be fabricated by

current photolithography; that is, the science of objects with smallest dimensions ranging from a few nanometers to less than 100 nanometers. In chemistry, this range of sizes has historically been associated with colloids, micelles, polymer molecules, phase-separated regions in block copolymers, and similar structures typically, very large molecules, or aggregates of many molecules. More recently, structures such as buckytubes, silicon nanorods, and compound semiconductor quantum dots have emerged as particularly interesting classes of nanostructures. In physics and electrical engineering, nanoscience is most often associated with quantum behavior, and the behavior of electrons and photons in nanoscale structures. Biology and biochemistry also have a deep interest in nanostructures as components of the cell; many of the most interesting structures in biology from DNA and viruses to subcellular organelles and gap junctions can be considered as nanostructures. The combination of the promise of new phenomena new science with an extension of an extremely important technology is the force that drives nanoscience. Nanoscience has now been with us for a decade. Technologies growing from it are still few, and the rate at which they have emerged has seemed slower than that in areas such as biotechnology. There will certainly be in fact, there already is an evolutionary nanotechnology, based on products that already exist, and that have micro- and nanometer-scale features. Commercial nanotechnology exists, and is in the robust health of early childhood. The more interesting question is whether there will be revolutionary nanotechnologies, based on fundamentally new science, with products that we cannot presently imagine. The nanotechnology that is already with us is that of microelectronics where engineers have already shown how to extend existing methods for making microelectronic devices





to new systems with sub-70-nm wires and components, materials science where many of the properties of polymers, metals, and ceramics are determined by 1–100 nm structures, and chemistry where nanometer- scale drugs are routinely used to control proteins and signaling complexes, and where macromolecules have dimensions of many nanometers. These technologies are evolutionary nano. The nanotechnology whose form and importance is yet undefined is revolutionary nano; that is, technologies emerging from new nanostructured materials (e.g., buckytubes), or from the electronic properties of quantum dots, or from fundamentally new types of architectures based on nanodevices for use in computation and information storage and transmission. Nanosystems that use or mimic biology are also intensely interesting. There is no question that revolutionary nanoscience exists in the laboratories now, and that new forms of nanotechnology will be important; it is just not clear at the moment how much of this exciting, revolutionary science will migrate into new technology, and how rapidly this migration will occur. The history of technology suggests, however, that where there is smoke, there will eventually be fire; that is, where there is enough new science, important new technologies will eventually emerge.

In the next paragraphs some aspects of nanoscience and nanotechnology for the improvement of human lives are described. Life, environment, energy and nanotechnology

Research should indentify the qualities of work, life and the environment to which citizens give highest priority and identify branches of nanotechnology most relevant to them. Nanotechnology will help ensure that we can produce enough food by improving inventory storage and the ability to grow at high yield and a diversity of crops locally.

Nanotechnology will also help with water resources, allowing low energy purification and desalination, and reducing water waste in manufacturing and farming. Nanoscale-related improvements in energy technology will reduce the dependence on fossil fuels, make photovoltaic energy production competitive with other sources, allow entrance into a potential hydrogen economy, and improve renewable energy systems like biomass. In order to preserve the environment, we would use nanotechnology to remediate waste and pollution, produce systems and materials that use resources most efficiently, recycle pollution into raw materials, and ensure safety and sustainability of new materials. Developments in cognitive sciences and humanities resulting from scientific and technological developments will increase their contribution to the quality of life. Potential risks and unexpected consequences need to be monitored and included in any assessment of overall changes of quality of life. Medicine and nanotechnology

Understanding the cell, that is, understanding life is one of the great unanswered questions in science. The cell is the quantum of biology the smallest and most fundamental unit the one from which the rest is built. The cell is a system of molecules and remarkable nanoscale machines functional molecular aggregates of great complexity. Understanding these molecular nanostructures in their full, mechanistic, molecular complexity is vital to a reductionist understanding of the cell. Doing so will require new methods of examining these systems: in isolation, in the cell, and in the organism. The methods that emerge from this research will help us to move closer to understanding human life and health, and thus toward nanomedicine. Nanostructures may also be useful in



delivering drugs, as imaging agents, and in clinical analysis. Ethical issues and nanotechnology

The news model of public involvement, in which technical experts and the media impart information to a passive audience, fails to bring about an informed public. We need information systems that facilitate two-way conversation. Innovative technologies bring about unintended consequences. Instead of trying to predict the future, it will be more fruitful to try to shape the future by building institutions that can learn while preserving core values. A range of projects could develop infrastructures for balanced and inclusive public participation in decision making, with many different, innovative models used to assure two-way interchange

between nano-engineers or scientists and their publics. There must be genuine respect for interdisciplinary discussion of ethical and social dimensions of nanoscale science, engineering, and technology. Research should be carried out to achieve better understanding of complex systems and uncertainty, and better understanding of how research directions themselves are decided. Risks and uncertainties are expected to increase with the transforming capabilities provided by nanotechnology, and must be evaluated by considering global factors in governance.

Some of problematic social trends and

ways nanotechnology could contribute to the solutions for these problems are presented in Table 1.

Table 1: Some of problematic social trends and ways nanotechnology could contribute to solutions

Social problems Nanotechnology contribution to solution Healthcare and working capacity of aging population Collapse of birth rate in most advanced nations, below level required for population stability Poverty and inequality, most urgently in under developed nations Threatened exhaustion of natural resources Environmental degradation, including global warming

Convergence of nanotechnology with biotechnology, information technology and neurotechnology would address chronic illnesses, losing sensorial capacity, and maintaining work capacity

Convergence of nanotechnology with biotechnology to overcome infertility Economic progress, fueled by technological developments requiring systematic control of nanoscale processes and materials Nano-enabled technologies for improved efficiency in use of non-renewable resources, including energy production, water filtration, and invention of many high-quality nano-fabricated substitute materials Reduced pollution from more efficient use of materials; specific new pollution remediation nanotechnologies; improved environmental


monitoring by means of nano-enabled sensor nets Numerous specific nanotechnology-based solutions, such as: sensors to detect bioterrorism substances; inexpensive smart labels to deter theft of valuable goods; armor and vehicle components from nanostructured materials

Security issues within industrial nations

Fresh approaches to disease diagnosis and treatment from nanotechnology; prevention of disease from better nutrition and from quick detection and treatment of conditions

Medical: diminishing returns from research; rising cost of health care

predisposing to disease

About the author: Pankaj Bharali was born in Duliajan, Dibrugarh, Assam. He obtained his B.Sc. from Government Science College, Jorhat (Dibrugarh University) in 1999 and M.Sc. in Chemistry from Gauhati University in 2002. After his masters he spent nearly two years in Material Science Division, NEIST (formerly RRL) Jorhat as junior research fellow under externally funded project. Latter on moved to IICT, Hyderabad to continue his doctoral research at I & PC Division, IICT under the guidance of Dr. B. M. Reddy, Deputy Director. Recently, he visited Ruhr University of Bochum, Germany for three months (October to December, 2007) under a bilateral DST-DAAD collaborative program. He has co-authored seven papers published in highly reputed international journals and presented eleven papers in seminar/conferences. His research interest includes synthesis and characterization of nanostructured metal oxides for different catalytic applications.

(Collection from web: Editor)


-------------------- --------------------

Richard P. Feynman “What I am going to tell you about is what we teach our physics students in the third or fourth year of

graduate school... It is my task to convince you not to turn away because you don't understand it. You see my physics students don't understand it... That is because I don't understand it. Nobody does.” ----------------------- -----------------------

Ph.D. Thesis Abstract


Abstract 1: Adsorption of Organic Anions on the Metal Oxide Surfaces

Dr. Manash R. Das [email protected]

The results of the studies recorded in the thesis provide the knowledge of kinetics of adsorption, adsorption behaviour of small aromatic organic anions at metal oxide−water interface at different pH and surface complexation. The title of the thesis is “Adsorption of organic anions on the metal oxide surfaces” and thesis has seven chapters. Chapter I: Introduction

In this chapter the importance of the adsorption studies of small aromatic organic anions on the metal oxide surfaces has been highlighted. Adsorption of surface-active agent at the solid-liquid interface is of immense importance in the field of mineral processing (Mahiuddin et al., 1989; Subramanian and Natarajan, 1991; Weissenborn et al., 1994), environment (Biber and Stumm, 1994) and geochemical processes (Mesuere and Fish, 1992a,b; Tombácz, et al., 2000). In the mineral processing industries surface-active agents are used to recover selectively the desired mineral from mineral mixtures adopting the dispersion-cum-settling or flocculation and flotation techniques. Sodium humate is a supramolecular species and an effective surface-active agent (Beckett, 1990) for the

beneficiation of iron ore (Mahiuddin et al., 1989; 1992). Due to structural complexity of humate (Figure 1), the interaction and adsorption behaviour of humate on the hematite and other metal oxides surfaces is ill defined. Therefore, small aromatic organic anions with well defined structure e.g. benzoate, salicylate, p-hydroxy benzoate and phthalate (Figure 2) with different polydispersity and polyfunctionality, which are considered to be constituting models of functional groups occurring in humic acid, are chosen for studying adsorption and surface complexation on the surfaces of hematite, alumina and silica. Therefore, depending on the structure, functionality and conformational factors, the adsorption profile and surface complexation of these model anions on the oxide surfaces are different (Ali and Dzombak, 1996a,b; Evanko and Dzombak, 1998). Their adsorption properties could be similar to humate (Ali and Dzombak, 1996a,b; Evanko and Dzombak, 1998). Both humate and small aromatic organic anions show the similar ligand exchange reaction involving carboxylic and phenolic OH groups and the hydroxyl group on metal oxide surfaces.

Figure 1 Most probable structure of humic acid

(Stevenson, 1994)

Adsorption of surface-active agent at the metal oxide-water interface depends on time, pH and the ionic strength of the medium. Kummert and Stumm (1980) reported 6 h to attain the state of equilibrium




for the adsorption of benzoate and salicylate on γ-Al O2 3. Whereas, Parfitt (1977) found that the state of equilibrium for adsorption of benzoate on goethite (α-FeOOH) surfaces was attained after one week. In the case of oleate-natural hematite system in aqueous medium, the state of equilibrium found to be 36 min (Ofor and Anusiem, 1999). In most of the reported studies, adsorption isotherms are carried out at arbitrary chosen equilibration time (Yost et al., 1990; Tejedor-Tejedor et al., 1992; Filius et al., 1997; Szekeres et al., 1998; Hur and Schlautman, 2003; Tombácz et al., 2004). Therefore, adsorption kinetics is an important parameter for subsequent adsorption isotherms of adsorption of surface-active agent at the metal oxide-water interface.


Benzoic acid Salicylic acid

P-hydroxy benzoic acid Phthalic acid Figure 2 Structure of small well-defined aromatic acids, which are the constituting models of functional groups occurring in humic acid

Fourier transform infrared (FTIR) spectroscopy studies provide the information regarding nature of surface complexation of small aromatic organic anion on metal oxide surfaces. Literatures have focused on the complexation of small aromatic organic

anions on the metal oxide surfaces (Biber and Stumm, 1994; Nordin et al., 1997, Klug and Forsling, 1999; Phambu, 2002; Rosenqvist et al., 2003). In the case of adsorbate containing carboxylic group the difference between the ν −(COOas ) and ν −(COOs ) bands, their relative shifting and boarding of the asymmetric carboxylic band have been considered for the plausible surface complexation structure on metal oxide and oxy(hydroxide) surfaces. Based on the shifting of ν − −(COO ) and ν (COOas s ) bands of benzoate after adsorption on bayerite (α-Al(OH)3), Phambu (2002) concluded that the benzoate forms bidentate bridging complex on bayerite surface. Biber and Stumm (1994) reported the different types of surface complexation of salicylate on the metal oxide and oxy(hydroxide) surfaces depending on the shifting of the ν − −(COO ) and ν (COOas s ) bands. Phthalate also form different types of surface complexes either outer sphere (Nilsson et al., 1996; Rosenqvist et al, 2003) or both outer- and inner-sphere (Nordin et al., 1997; Persson et al., 1998; Klug and Forsling, 1999) complexes with aluminium oxide, aluminium (oxy)hydroxide and goethite depending on the pH and ionic strength of the medium. Surface complexation of small aromatic organic anions with different polydispersity and polyfunctionality at different pH and ionic strength are markedly different (Nordin et al., 1997; Persson et al., 1998; Rosenqvist et al., 2003). Therefore, surface complexation of the model anions onto different adsorbents using FTIR spectroscopy would be worth to this field of research. Chapter II: Experimental

In this chapter, the experimental techniques for the measurement of zeta potential, kinetics of adsorption at three different temperatures, adsorption isotherms

COOH COOH

OH

COOH

OH

COOH

COOH



and FTIR spectra have been described. The adsorbents and adsorbates used in the entire study with purity are also included here. Chapter III: Kinetics and Adsorption Behaviour of Salicylate on α-Alumina in Aqueous Medium

Zeta potential of α-alumina and its influence on the adsorption behaviour of salicylate on α-alumina surfaces, kinetics of adsorption, adsorption isotherms at different pH values and the influence of the ionic strength on the adsorption have been discussed in this chapter. Thermodynamic parameters are estimated from the rate constant for adsorption. Finally, surface complexation of salicylate on α-alumina surface at pH 5 and 7 in aqueous medium is also proposed.

The zeta potential of α-alumina at different ionic strengths was measured as a function of pH of the medium at 25 oC. The isoelectric point (IEP) of α-alumina was found to be in between pH 7.15 to 7.3. Kinetics of adsorption of salicylate on α-alumina surface was studied at pH 5 and at 25, 30 and 40 oC. The state of equilibrium was obtained after 2.5 h within the temperature range of the study. Different kinetics models e.g. a first order kinetics equation proposed by Bajpai (1994), pseudo first order Lagergren equation (Lagergren, 1898), pseudo second order kinetics equation (Tien and Huang, 1991; Ho and McKay, 1999; Ho et al., 2001), intra-particle diffusion (Ho and McKay, 1998) and liquid film diffusion models (Boyd et al., 1947) were applied to evaluate the rate constant. The temperature was found to influence the adsorption density of salicylate on α-alumina at equilibration. The adsorption density of salicylate on α-alumina surface at 300 min is around 1.6 and 3.0 times more at 30 and 40 oC, respectively than that at 20 oC. The variation of adsorption density of

salicylate on α-alumina was studied over a wide range of concentrations of salicylate in aqueous medium over the pH range 4−9. The adsorption isotherms were found to be Langmuir in nature. The maximum adsorption density was found to be 6.348 μmol m−2 at pH 4, which decreases with pH up to 7 and then it become almost constant. At IEP (pH 7.2) the adsorption density is found to be ~0.5 μmol m−2 as against the expected value of zero. This is expected due to the fact that at IEP of α-alumina, the neutral surface site are available and salicylate is interacting with the >AlOH (surf). The adsorption density of salicylate on α-alumina surface decreases with the increase the ionic strength of the medium. For example, at pH 4 adsorption density decreases by ~39% as the ionic strength increases from 0.5 to 10 mmol dm−3. The activation energy for adsorption is estimated using Arhenius equation. The positive ΔH (19.10 kJ mol−1) suggests that the adsorption process is endothermic in nature.

The FTIR spectra of salicylate after adsorption on α-alumina surfaces at pH 5 and 7 were recorded for obtaining the bonding properties of salicylate. The frequency due to phenolic group is shifted by 13 cm−1 (1253 to 1266 cm−1) after adsorption, which is due to the intramolecular hydrogen bonding between the phenolic hydrogen and carboxylic oxygen. Therefore, phenolic group is not deprotonated. The shifting of characteristic peak frequency of −COO− and appearance of a new band at ~1700 cm−1 due to >C=O indicate that the salicylate is coordinate monodentally with respect to the carboxyl group. Chapter IV: Kinetics and Adsorption Behaviour of Benzoate and Phthalate at the α-Alumina−Water Interface: Influence of Functionality



This chapter presents the comparative study of adsorption kinetics at a fixed pH, adsorption isotherms at different pH values, influence of ionic strength on the adsorption behaviour and the nature of surface complexation of benzoate and phthalate onto α-alumina surfaces. The influence of functionality on the adsorption of benzoate and phthalate on α-alumina surfaces has been discussed in this chapter.

The IEP of α-alumina was found to be 6.7, which is 2.5 unit lower than the reported value. The reason for the lower IEP of α-alumina is the presence of less number of surface hydroxyl groups. Kinetics of adsorption study showed that the state of adsorption equilibrium of benzoate at α-alumina-water interface is attained at 30 h within the temperature range of the study (25−40 oC). In the case of phthalate-α-alumina system, adsorption density of phthalate on α-alumina surfaces increases upto ~25 h at 30 and 40 oC after that it decreases with the increase in adsorption time. But at 25 oC state of equilibrium is attained at 10 h and beyond 37 h adsorption density decreases. The rate constant for adsorption of benzoate− and phthalate−α-alumina systems was estimated using kinetics models like a first order kinetics equation proposed by Bajpai (1994), pseudo first order Lagergren equation and pseudo second order kinetics equation. The variation of adsorption density of benzoate and phthalate on α-alumina surfaces was carried out over a wide range of concentrations of an adsorbate at a fixed ionic strength, I = 5 × 10−4 mol dm−3 and pH 5−10. The adsorption isotherms for both the systems were found to be Langmuir in nature. The maximum adsorption density of phthalate is 1.1−5.1 times more than that of benzoate on the same adsorbent under similar condition. This difference is attributed to the presence of an adjacent −COOH group in phthalate. The adsorption density of benzoate and phthalate

on α-alumina surface decreases with the increase in ionic strength from 0.05 to 10 mmol dm−3 depending on the pH of the medium. The positive ΔH values suggest that the adsorption process for the both the systems are endothermic in nature. The more negative Gibbs free energy of phthalate−α-alumina than that of benzoate−α-alumina implies that the adsorption of phthalate on α-alumina is highly favorable than benzoate on the same adsorbent. The solubility of α-alumina in presence of benzoate and phthalate was found to be depended on the pH of the medium and the concentration of sodium chloride. The surface complexation of benzoate and phthalate on α-alumina surfaces was investigated using the FTIR spectroscopy. Benzoate forms outer-sphere complexes with α-alumina surfaces at pH 5 and 6 depending on the shifting of the asymmetric and symmetric −COO− bands. Whereas phthalate forms both outer- and inner-sphere surface complexes with α-alumina surfaces. Chapter V: Kinetics and Adsorption of Benzoate and Salicylate at the Natural Hematite−Water Interface

The zeta potential of natural hematite, kinetics of adsorption, adsorption isotherms at different pH values and at a fixed ionic strength, I = 5×10−4 mol dm−3 and the thermodynamic parameters have been discussed in this chapter.

The zeta potential of natural hematite as a function of pH at different ionic strengths was measured at 25 oC. The IEP of natural hematite was found to be 5.80. Kinetics of adsorption of benzoate and salicylate onto natural hematite surfaces have been carried out at pH 5 and at a fixed ionic strength, I = 5×10−4 mol dm−3. The state of equilibrium was attained at 144 and 70 h for benzoate and salicylate, respectively. The rate constant for benzoate−natural hematite and



salicylate−natural hematite systems increases with the increase in temperature. The adsorption isotherms for both the systems were Langmuir type up to pH 8. The Γmax (adsorption density at saturation) for benzoate is ~2.7−13.7 times more than that of salicylate depending on the pH of the suspension. The reason is that, unlike benzoate salicylate covers more surface site of hematite surfaces. The activation energy (estimated using rate constant of Bajpai kinetics model) for the adsorption of salicylate onto the natural hematite is higher than that of benzoate on the same adsorbent resulting in lower Γmax of salicylate−natural hematite systems. The negative ΔH implies that the adsorption of benzoate and salicylate on natural hematite surfaces are exothermic process. Chapter VI: Influence of Functionality on the Adsorption of P-Hydroxy Benzoate and Phthalate at the Hematite−Water Interface

The kinetics of adsorption, adsorption

isotherms, influence of ionic strength on the adsorption and surface complexation of p-hydroxy benzoate and phthalate on hematite surfaces have been discussed in this chapter. Influence of functionality of the adsorbate on the adsorption has also been compared in this chapter.

Kinetics of adsorption of p-hydroxy benzoate and phthalate on hematite-water interface were investigated at constant ionic strength, I = 5×10−4 mol dm−3, pH 5 and at three different temperatures. The state of equilibrium for the adsorption of p-hydroxy benzoate on hematite surface was attained at 70 h whereas for phthalate-hematite system it was 30 h. Different kinetics models were applied for evaluating the rate constant. The pseudo second order kinetics model fits the kinetics data comparatively better and results show that the rate constant of

phthalate−hematite system is ~5.7−14.7 times greater than p-hydroxy benzoate−hematite system at a fixed temperature. The variation of adsorption density of p-hydroxy benzoate and phthalate onto hematite surfaces as a function of concentration of adsorbate was studied over pH range 5−9 and at a constant ionic strength, I = 5×10−4 mol dm−3. The adsorption isotherms for both the systems were Langmuir in nature. The Γmax decreases with the increase in pH of the medium. The Γmax of p-hydroxy benzoate is 1.6 times more than that of phthalate on the same adsorbent at pH 5 and 30 oC in spite of an additional adjacent carboxylic group in phthalate. This is due to the fact that the surface site covered by phthalate is more than that of p-hydroxy benzoate on hematite surface. The activation energy for the adsorption of p-hydroxy benzoate at the hematite−water interface is ~1.8 times more than that of phthalate on the same adsorbent. The ΔH for p-hydroxy benzoate−hematite and phthalate−hematite systems are found to be –40.71 and –21.96 kJmol−1, which imply that in both systems the adsorption process is exothermic in nature.

The surface complexation of p-hydroxy benzoate and phthalate on hematite surface were investigated using FTIR spectroscopy. The phenolic νC-O appears at ~1271 cm−1 after adsorption of p-hydroxy benzoate on hematite surfaces, which shifted by 10 cm−1 to higher frequency region. The phenolic OH group is not deprotonated and therefore, it is not participating in the surface complexation. The shifting of the characteristic peak frequency of −COO−

suggests that the p-hydroxy benzoate forms a bindentate mononuclear surface complex with hematite surfaces at pH 5 and 7. On the other hand, depending on shifting of νas(−COO−) and νs(−COO−) bands, phthalate on adsorption forms outer-sphere surface



complex with hematite surfaces at pH 5, 6 and 9. Chapter VII: Kinetics, Adsorption Isotherms and Thermodynamic Parameters for Adsorption of Salicylate at the Silica−Water Interface

This chapter includes kinetics of adsorption, adsorption isotherms at different pH, effect of ionic strength on the adsorption and the thermodynamic parameters for adsorption of salicylate at the silica-water interface.

Kinetics of adsorption of salicylate onto silica surfaces were carried out at pH 5 and at a fixed ionic strength, I = 5×10−4 mol dm−3. The state of equilibrium was attained at 320 h and found to be independent on the temperature. Bajpai kinetics model (1994) comparatively yields better rate constant, which increases with the increase in temperature. The variation of adsorption density of salicylate on the silica surfaces with wide range of concentrations of salicylate was studied in aqueous medium over pH range 5−9 and at a fixed ionic strength, I = 5×10−4 mol dm−3 NaCl. The Langmuir adsorption isotherm equation was used to fit the experimental data. The Γmax value decreases (0.1456 to 0.0318 μmol m−2) with the increase in pH of the medium upto pH 8 and at pH 9 it becomes zero. The activation energy for this system is found to be 18.30 kJmol−1. The negative ΔH (−18.04 kJmol−1) implies that the adsorption of salicylate on silica surfaces is exothermic in nature.

References Ali, M.A.; and Dzombak, D.A., Environ.

Sci. Technol., 1996a, 30, 1061. Ali, M.A.; and Dzombak, D.A., Geochim. Cosmochim. Acta, 1996b, 60, 291. Bajpai, A.K., J. Appl. Polym. Sci., 1994, 51, 651.

Beckett, R., Surface and Colloid Chemistry in Natural Waters and Water Treatment, Plenum Press, New York, 1990. Biber, M.V.; and Stumm, W., Environ. Sci.

Technol., 1994, 28, 763. Boyd, G.E.; Adamson, A.W.; and Myers

L.S., J. Am. Chem. Soc., 1947, 69, 2836 Evanko, C.R.; and Dzombak, D.A., Environ.

Sci. Technol.,1998, 32, 2846. Evanko, C.R.; and Dzombak, D.A., J. Colloid Interface Sci., 1999, 214, 189. Filius, J.D.; Hiemstra, T.; and Van

Riemsdijk, W.H., J. Colloid Interface Sci., 1997, 195, 368.

Ho, Y.S.; and Mckay, G., Trans. IChemE. B, 1999, 77, 165.

Ho, Y.S.; and Mckay, G., Trans. IChemE. B, 1998, 76, 183.

Ho, Y.S.; Ng, J.C.Y.; and Mckay, G., Separ. Sci. Technol., 2001, 36, 241.

Hur, J.; and Schlautman, M.A., J. Colloid Interface Sci., 2003, 264, 313.

Klug, O.; and Forsling, W., Langmuir, 1999, 15, 6961.

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Lagergren, S., Ksver. Vetenskapsakap. Handingar, Band, 1898, 24, 1.

Mahiuddin, S.; Bondyopadhyay, S.; and Baruah, J.N., Int. J. Miner. Process, 1989, 26, 285.

Mahiuddin, S.; Suryanarayan, I.; Dutta, N.N.; and Borthakur, P.C.; Colloids Surf., 1992, 64, 177.

Mesuere, K; and Fish, W., Environ. Sci Technol., 1992a, 26, 2357.

Mesuere, K; and Fish, W., Environ. Sci Technol., 1992b, 26, 2365

Nilsson, N.; Persson. P.; Lövgren, L.; and SjÖberg, S., Geochim. Cosmochim. Acta, 1996, 60, 4385.

Nordin, J.; Persson. P.; Laiti, E.; and SjÖberg, S., Langmuir, 1997, 13, 4085

Ofor, O.; and Anusiem, A.C.I., J. Colloid Interface Sci., 1999, 220, 219.

Parfitt, R.L.; Farmer, V.C.; and Russel, J.D., J. Soil. Sci., 1977, 28, 29.


Persson. P.; Nordin, J.; Rosenqvist, J.; Lövgren, L.; Öhman, L.-O.; and SjÖberg, S., J. Colloid Interface Sci., 1998, 206, 252

Persson. P.; Nordin, J.; Rosenqvist, J.; Lövgren, L.; Öhman, L.-O.; and SjÖberg, S., J. Colloid Interface Sci., 1998, 206, 252

Phambu, N., Appl. Spectrosc., 2002, 56, 756. Phambu, N., Appl. Spectrosc., 2002, 56, 756. Rosenqvist, J.; Axe, K.; SjÖberg, S.; and

Persson. P, Colloids Surf. A: Physicochem. Eng. Aspects, 2003, 220, 91.

Rosenqvist, J.; Axe, K.; SjÖberg, S.; and Persson. P, Colloids Surf. A: Physicochem. Eng. Aspects, 2003, 220, 91.

Stevenson, F.J., Humus Chemistry: Genesis, Composition, Reactions, John Wiley and Sons, 2nd ed, USA, 1994

Stevenson, F.J., Humus Chemistry: Genesis, Composition, Reactions, John Wiley and Sons, 2


Subramanian, S.; and Natarajan, K. A., Mineral Engineering, 1991, 4, 587.

Subramanian, S.; and Natarajan, K. A., Mineral Engineering, 1991, 4, 587.

Szekeres, M.; Tombácz, E.; Ferencz. K.; and Dékány, I., Colloids Surf. A: Physicochem. Eng. Aspects, 1998, 141. 319.

Szekeres, M.; Tombácz, E.; Ferencz. K.; and Dékány, I., Colloids Surf. A: Physicochem. Eng. Aspects, 1998, 141. 319.

Tejedor-Tejedor, M.I.; Yost, E.C.; and Anderson, M.A., Langmuir, 1992, 8, 525. Tejedor-Tejedor, M.I.; Yost, E.C.; and Anderson, M.A., Langmuir, 1992, 8, 525. Tien, C.T.; and Huang, C.P., Trace Metals in

the Environmental, Vol 1, Heavy Metal in the Environment, Elsevier, Amsterdam, 1991.

Tien, C.T.; and Huang, C.P., Trace Metals in the Environmental, Vol 1, Heavy Metal in the Environment, Elsevier, Amsterdam, 1991.

Tombácz, E.; Dobos, A.; Szekeres, M.; Narres, H.D.; Klumpp, E., and Dékány, I., Colloid Polym. Sci., 2000, 278, 337.

Tombácz, E.; Dobos, A.; Szekeres, M.; Narres, H.D.; Klumpp, E., and Dékány, I., Colloid Polym. Sci., 2000, 278, 337.

Tombácz, E.; Libor, Z.; Illés, E.; Majzik. A.; and Klumpp, E., Org. Geochem, 2004, 35, 257.

Tombácz, E.; Libor, Z.; Illés, E.; Majzik. A.; and Klumpp, E., Org. Geochem, 2004, 35, 257.

Weissenborn, P. K.; Warren, L. J.; and Dunn, J. G., Int. J. Miner. Process, 1994, 42, 191.

Weissenborn, P. K.; Warren, L. J.; and Dunn, J. G., Int. J. Miner. Process, 1994, 42, 191.

Yost, E.C.; Tejedor-Tejedor, M.I.; and Anderson, M.A., Environ. Sci. Technol., 1990, 24, 822.

Yost, E.C.; Tejedor-Tejedor, M.I.; and Anderson, M.A., Environ. Sci. Technol., 1990, 24, 822.

About the author: About the author: Dr. Manash Ranjan Das hails from Khetri, Kamrup District, Assam. He did his B.Sc from Jagiroad College in the year 1998. He did his Masters in Science in chemistry (Special paper: Physical Chemistry) from Gauhati University in the year 2000. Then he joined Material Science Division of North East Institute

of Science and Technology (NEIST)Assam [Formerly: Regional Research Laboratory, Jorhat] for his Ph.D. He received his Ph.D. in the year 2007. Title of his thesis is "Adsorption of Organic Anions on the Metal Oxide Surfaces". Presently he is doing his postdoctoral research in Institut de Recherche Interdisciplinaire (IRI, USR CNRS-3078), Institut d’Electronique, de Microélectronique et de Nanotechnologie (IEMN, UMR CNRS-8520), France.

Dr. Manash Ranjan Das hails from Khetri, Kamrup District, Assam. He did his B.Sc from Jagiroad College in the year 1998. He did his Masters in Science in chemistry (Special paper: Physical Chemistry) from Gauhati University in the year 2000. Then he joined Material Science Division of North East Institute

of Science and Technology (NEIST)Assam [Formerly: Regional Research Laboratory, Jorhat] for his Ph.D. He received his Ph.D. in the year 2007. Title of his thesis is "Adsorption of Organic Anions on the Metal Oxide Surfaces". Presently he is doing his postdoctoral research in Institut de Recherche Interdisciplinaire (IRI, USR CNRS-3078), Institut d’Electronique, de Microélectronique et de Nanotechnologie (IEMN, UMR CNRS-8520), France.

nd ed, USA, 1994

---------------------000--------------------- ---------------------000--------------------- Charles Darwin Charles Darwin “To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I confess, absurd in the highest degree.”

“To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I confess, absurd in the highest degree.” ---------------------000--------------------- ---------------------000---------------------

Paul A. M. Dirac Paul A. M. Dirac “If there is a God, he's a great mathematician.” “If there is a God, he's a great mathematician.”

---------------------000--------------------- ---------------------000---------------------

Abstract 2Abstract 2: De Novo Designed Molecules Based on Non-covalent Interactions: Design, Synthesis and Structural Studies


Dr. Pranjal K. Baruah [email protected] Chapter I describes the design, synthesis and structural investigation of hydrogen bond-mediated highly stable molecular duplexes, and further related studies.

Chapter 2 describes the design, synthesis and structural investigations of novel foldamers (conformationally ordered synthetic oligomers) derived from �α-amino acid and aromatic amino acid conjugates.

The self-assembling systems described herein have been shown to form strong molecular duplexes, as evident from ESI-Mass, X-ray analysis, and extensive NMR studies. It is noteworthy that these self-assembling systems, exhibiting “degenerate porototropy can be readily accessed in three steps. This chapter also describes the

It also describes the design, synthesis and structural studies of novel hybrid foldamers based on Aib-Amb motif.

attempts made towards synthesis of more stable hydrogen bonded molecular duplexes.




Chapter 3 describes the design, synthesis and structural studies of a new class of aromatic oligoamide foldamers based on binaphthol (BINOL) monomers. Series of oligomers with differing chirality of the individual BINOL building blocks and mixed sequences of alternate BINOL and pyridyl building blocks have been

synthesized and structurally characterized. It is shown that oligomers consisting of only three building blocks of the same class, which differ in chirality due to restricted rotation, provide a great number of highly ordered structures with remarkable shape diversity and structural architecture.



List of publications:

3. Enforcing Periodic Secondary Structures in Hybrid Peptides: A Novel Hybrid Foldamer Containing Periodic γ-Turn Motifs: Baruah, P. K.; Sreedevi, N. K.; Gonnade, R.; Ravindranathan, S.; Damodaran, K.; Hofmann, H.-J.; Sanjayan, G. J. J. Org. Chem.

1. Self-assembly with degenerate prototropy: Baruah, P. K.; Gonnade, R.; Phalgune, U. D.; Sanjayan, G. J. J. Org. Chem. 2005, 70, 6461-6467. 2. The solid-state behaviour of 4,6-dioxo-5,5-diethylenepyrimidine-2-isobutylurea: Spencer, E. C.; Howard, J. A. K.; Baruah, P. K.; Sanjayan, G. J. CrystEngComm 2006, 8, 468–472.

2007, 72, 636-639. 4. BINOL-Based Foldamers - Access to Oligomers with Diverse Structural Architectures; Baruah, P. K.; Gonnade, R.;


http://dx.doi.org/10.1021/jo062032w


Chandrasekhara Venkata Raman

Rajamohanan, P. R.; Hofmann, H.-J.; Sanjayan, G. J. J. Org. Chem. 2007, 72, 5077-5084. “When the Nobel award

was announced I saw it as a personal triumph, an achievement for me and my collaborators -- a recognition for a very remarkable discovery, for rehad pursued for 7 years. But when I sat in that crowded hall and I saw the sea of western faces surrounding me, and I, the only Indian, in my turban and closed coat, it dawned on me that I was really representing my people and my country. I felt truly humble when I received the Prize from King Gustav; it was a moment of great emotion but I could restrain myself. Then I turned round and saw the British Union Jack under which I had been sitting and it was then that I realized that my poor country, India, did not even have a flag of her own - and it was this that triggered off my complete breakdown.”

5. 6,6-Dibenzyltetrazolo[1,5-a]pyrimidine-5,7(4H,6H)-dione; Baruah, P. K.; Gonnade, R.; Sanjayan, G. J. Acta Cryst. E 2007, E63, o3550.

aching the goal I 6. Aib-rich Sheet-Forming Abiotic Foldamers: Baruah, P. K.; Sreedevi, N. K.; Majumdar, B.; Pasricha, R.; Poddar, P.; Ravindranathan, S.; Sanjayan, G. J. Chem. Commun., 2008, 712–714. About the author: Pranjal Baruah has received his Ph. D. from National Chemical Laboratory in August, 2007. He secured 1st nd class 2 position both in his B. Sc. and M. Sc. degrees from Dibrugarh University. Presently he is pursuing his Post Doctoral research in UNC Chapel Hill, USA. ---------------------000--------------------- ---------------------000---------------------

The Central Dogma of molecular biology states that "DNA makes RNA makes protein". (Collected from web: Editor)



Information about members:


Ms Nabanita Bhattacharyya hasreceived her B.Sc. from Nalbari College and M.Sc. in Botany (Advanced Plant Physiology and Biochemistry) from Gauhati University, Assam in 2000. After her M.Sc., she had joined the Department of Biotechnology, Gauhati University to pursue her Ph.D under the guidance of Prof. S. Sarma. Later, she has joined as a Lecturer in the Department of Botany, Nowgong College, Assam. Her current research interests include Plant Physiology, Biochemistry and Environmental Biotechnology. At this point we would like to thank Ms. Nabanita Bhattacharyya for her regular contributions in the NE Quest.

Dr. Maumita Paul presently residing in Kolkata, originally from Karimganj, Assam. She did her B. Sc. in Chemistry from Handique Girls College, Guwahati. After completion of her M.Sc. in Organic Chemistry from Gauhati University (2000), Guwahati, Assam, in 2002 she joined Department of Chemistry, Gauhati University as a Project Assistant in a UGC Major Research Project under the supervision of Dr. D. C. Deka. In the year 2003, she qualified for JRF-CSIR and continued her research work in the Department of Chemistry, GU. She

2007 and her Ph. D thesis entitles “Studies on the Reactivity of some α,β-Unsaturated Esters Towards Organotin Hydrides”.

received her Ph. D degree in December,

Ms. Rupjyoti i h

n 2003 from the

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autam Buddha

Thousands of candles

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Gogo ails from Jagiroad, Assam. She did her B. Sc. from Jagiroad College in 2000 securing 1st class 1st position with distinction and completed her M. Sc. idepartment of Physics, Gauhati University, Guwahati, opting High Energy Physics and Condensed Matter Physics as special papers. In June 2003, she joined the Ph. D. course in High Energy Physics at Gauhati University on a topic, entitled “A study of self-similarity in structure function of the nucleon and approximate solutions of QCD evolution equations at small x” under the guidance of Prof. Dilip Kumar Choudhury. Currently she is working as CSIR-SRF on the same project.

-- G “can be lit from a single candle, and the life of the candle will not be shortened. Happiness never decreases by being shared.” --



Higher Study Abroad

enrolled in the Ph.D. program are expected to have the ability to independently plan an

ate Program -I(IGP-I) or International Gradua

Studentsd implement research that will result in new academic findings. Interdisciplinary research

projects are especially encouraged to promote and develop a more open-minded perspective, better communication skills, and strong leadership skills.

Students can apply to either International Gradute Program -II(IGP-II). Note that scholarships available are different in the programs. To

apply for a Monbukagakusho Scholarship (Japanese Government Scholarship) with a ‘university recommendation’, an applicant needs to enroll in the International Graduate Program-I(IGP-I). See Scholarship page. Program Enrolment Application Period

November- International Graduate Program-I (IGP-I) September Mid December

September March-April International Graduate Program-II (IGP-II)

April November

cholarshipS

he Graduate School of Science and Technology has a program that offers scholarships to those

. University Recommendation Scholarship (From the list of students who have successfully

NBUKAGAKUSHO:MEXT) Scholarship through University

Twho have successfully passed the entrance examination. A

passed the entrance exam, the University will select outstanding students and recommend them to a scholarship program. These students will be the recipients of the scholarship they have been recommended to.) 1. Japanese Government (MO

Recommendation: Master's Program (IGP), Ph.D. Program (IGP-I) ADB Scholarship: 2. Master's Program (IGP)（Only those with work experience may

3. Scholarship: Availability varies each year.

. Other Scholarships

u need to apply to before enrolling in graduate school. Japanese

apply). Fujiwara

4. Yoshida Scholarship: Availability varies each year.

B1. Scholarships yo

Government (MONBUKAGAKUSHO : MEXT) scholarship（Embassy Nominated

http://www.st.keio.ac.jp/english/admissions/scholarship/index.html

http://www.st.keio.ac.jp/english/admissions/masters_program/international_graduate.html

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http://www.st.keio.ac.jp/english/admissions/ph_d_program/international_graduate_01.html


Students） : Available for Japanese and English-based master’s and Ph.D. program students.

2. Scholarships you need to apply to after enrolling in graduate school. Exemption from tuition, and other scholarships from private and regional public organizations, etc.

For more information please read details at the Keio University International Center


or JASSO (Japan Student Services Organization). Some other Scholarships • Japanese Government (MONBUKAGAKUSHO:MEXT) scholarship through University

Recommendation: Recipients of this award will receive financial aid from the Monbukagakusho Scholarship (Japanese Government Scholarship Program). Those wishing to apply for this scholarship need to have a “university recommendation”. The scholarship covers the costs of one roundtrip air-ticket, the admission fee, tuition, plus a monthly stipend for a maximum of five years. The stipend is 170,000 yen for the first year and 160,000 yen from the second year on. This is based on the normal time it takes to complete postgraduate studies (two years as a master's student and three years as a Ph.D. student). Please note that the applicant for the scholarship must be no more than 35 years of age as of April 1 of the year of enrollment.

• ADB Scholarship Program: The International Graduate Program in the School of Science and Technology selects a few students each year who are pursuing a master's degree and recommends them to the Asian Development Bank to become recipients of their scholarship. Only recipients who plan to return to their home country after completion of their master's degree are eligible. The scholarship covers round trip airfare, the admission fee and tuition, and gives a monthly stipend equivalent to that of the Japanese Government Scholarship for a maximum of 2 years. Please note that the applicant for the scholarship must be no more than 35 years of age as of April 1 of the year of enrolment.

Contact Information Admissions Office (AO) Graduate School of Science and Technology Keio University 3-14-1 Hiyoshi, Kohoku-ku, Yokohama Kanagawa 223-8522 JAPAN Fax: +81-45-566-1464 E-mail: [email protected] What are the eligibility requirements for the Ph.D. program?

Eligibility for Admission: 1. Expecting a conferral of a master’s degree, a professional master’s degree or a degree that

is equivalent to the aforementioned degrees from an institution outside Japan before the enrolment.

2. Has a master’s degree, a professional master’s degree or a degree that is equivalent to the aforementioned degrees.

Some upcoming research positions are listed in the following pages……………

http://www.ic.keio.ac.jp/en/study/mext/index.html

http://www.ic.keio.ac.jp/en/study/mext/index.html

http://www.ic.keio.ac.jp/en/life/scholarship/outline.html

http://www.jasso.go.jp/study_j/index_e.html

http://www.jasso.go.jp/study_j/index_e.html




(1) Job Title: Postdoctoral position in the Department of Chemistry at Nagoya Univ., Japan in Synthetic Organic Chemistry, Profs. Noyori and Saito; SAI01/08 Job Number: 4003115 (Ref.#. SAI01/08) Date Posted: 03/31/2008 Application Deadline: Open Until Filled

Job Details:A position as postdoctoral fellow in the area of synthetic organic chemistry is open in the group of Profs. Ryoji Noyori and Susumu Saito in the Department of Chemistry at Nagoya University. For one year starting any time, with possibility of extension for another year. Two or three vacant slots would be open from October 1st, 2008. Please feel free to get in touch. Research Area: Our emphasis is on the exploration of new synthetic methods, strategies, and concepts to solve challenging synthetic problems to realize ideal chemical synthesis and molecular catalysis, thereby putting forward the revolution of environmentally benign chemical technology for 21th century. Representative interests: (i) Activation of alcohols and utilizing them as electrophiles using molecular catalysis (ii) Degradation of biomass such as cellose, amylose, or lignin, etc. to make them as important carbon resources for 21th century (iii) Activation of CO2 and using it as a important C1 resource for the 21th century’s chemical synthesis (iv) Chemical Synthesis of sugar and deoxy-sugar derivatives of pharmaceutical importance (v) Chemical synthesis without waste: changeover of molecular catalysis from strongly acidic or basic to neutral (vi) Hydrogenation using novel molecular catalysts (vii) Molecular manipulation of hydrogen bonds and dative bonds for generating molecular catalysis (viii) Molecular catalysis based on hydrogen atom transfer (ix) Chemical process involving H2O: embedding water into, or liberating water from, a carbon chain Please check out the web site at: http://noy.chem.nagoya-u.ac.jp/index(eng).htm Salary: Approximately 4,000,000JPY per year. Application Materials: following documents should be presented. (1) Curriculum vitae with photograph (2) Publication list (books, original papers, reviews described separately) (3) Abstract of research results: 1 page (4) The reasons why you are interested in this position (5) Please arrange for two recommendation letters sent upon request directly to Dr. Berthold Fischer at [email protected] Preference will be given to candidates with strong background directly related to relevant research fields. Candidates who did not previously publish several papers in international, peer-reviewed journals and cannot make a statement why exactly they want to join this research group and should be considered for this position will not receive a reply. Contact: Dr. Berthold Fischer Nagoya University Furo-cho Chikusa-ku Nagoya, Aichi 464-8602 Japan Email: [email protected] Institution Web Site: http://noy.chem.nagoya-u.ac.jp/index(eng).htm



http://noy.chem.nagoya-u.ac.jp/index(eng).htm



(2) Job Title: PhD positions available at the Department of Chemistry, Nagoya University, Japan Job Number: 4003035 Date Posted: 03/13/2008 Application Deadline: Open Until Filled

Several PhD positions are available immediately at the Department of Chemistry, Nagoya University, Japan within the framework of a newly established Global-COE (Global Center of Excellence) devoted to the “Elucidation and Design of Materials and Molecular Functions”. 17 Research groups are involved in this new Global-COE from a wide range of topics like (1) “Highly Efficient Chemical Synthesis” through selective molecular catalysis; (2) “Use of Polymer Science for Development of Molecules with Novel Properties and Functions” including higher-order structure control for polymers and supramolecules; (3) “Development of Molecules with New Functions Through Nanochemistry” for nanocarbons, thin films, and supramolecular materials; and (4) “Chemical Aspects of Life Science” for understanding the complexity of biological phenomena from a chemical viewpoint. More detailed information can be found in the web page http://gcoe.chem.nagoya-u.ac.jp This Global-COE will develop young global research leaders responsible for the future of materials science through comprehensive and world-class education and research for creating new trends in development of molecular functions in materials science. The Department of Chemistry at Nagoya University is proud to be the home of Nobel Laureate Prof. Ryoji Noyori. For more information please contact directly: Contact: Dr. Berthold Fischer Nagoya University Furo-cho Chikusa-ku Nagoya, Aichi 464-8602 Japan Email: [email protected] Online Application: Apply for this position from Employer's website (3) Job Title: Ph.D. Studentship in Theoretical Physics, Erlangen, Germany

At Institute of Optics, Information & Photonics, Erlangen, Germany, Max Planck Junior Research Group “Nonlinear Photonic Nanostructures”Field(s): theoretical physics Application deadline: Sep 01 (Mon), 2008

Contact: Fabio Biancalana E-mail: [email protected]

Job description: Candidates are sought for 1 fully funded PhD studentship to work on the theoretical design of a working all-optical diode, based on Photonic Crystals with a quasiperiodic arrangement of the layers. The final aim of this PhD project is to develop new analytical and numerical techniques to study Photonic Crystals based on conceptually new designs. This will require the study of the linear and non-linear optical properties of Photonic Crystals. Knowledge of Classical Electromagnetism is essential. Please visit webpage at http://www.optik.uni-erlangen.de/mpf/php/abteilung3/jrg/index.html. This post is available from 1 September 2008, but the position will remain open until a suitable candidate is found. A letter of application containing at least 1 reference letter and a full CV containing a detailed description of the candidate's knowledge and expertise, should be emailed directly to Dr. Fabio Biancalana: [email protected]

http://gcoe.chem.nagoya-u.ac.jp/

http://www.universityjobs.com/jobs/applyforjob.php?jobid=4003035

http://gcoe.chem.nagoya-u.ac.jp/eng/recruitment/


http://www.optik.uni-erlangen.de/mpf/php/abteilung3/jrg/index.html




(4) Job Title: Postdoc Position in Self-Assembly of Block Polypeptides At Department of Physics and Frimat Center for Nanomaterials, Field(s): polymer physics Application deadline: Jun 01 (Sun), 2008 Contact: Prof. Dr. Raffaele Mezzenga E-mail: [email protected] Address: Department of Physics and Frimat Center for Nanomaterials University of Fribourg Chemin du Musée 3 CH - 1700 Fribourg Switzerland

Job description: A postdoctoral position is available in the field of self-assembly of block copolypeptides. Outstanding candidates with a strong background in polymer physics/polymer chemistry are encouraged to apply. The candidate should have polymer synthesis skills and be familiar with Small Angle x-ray Scattering (SAXS). Additional knowledge in Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM) and the other physico-chemical techniques is an advantage. Working language is English. Competitive salaries are offered. This project is line collaboration with EPFL. Starting date: end 2008-January 2009. Interested candidate can send CV, motivation letter and at least two references to: Prof. Dr. Raffaele Mezzenga Department of Physics and Frimat Center for Nanomaterials University of Fribourg Chemin du Musée 3 CH - 1700 Fribourg Switzerland [email protected] (5) Job Title: Postdoctoral Research Fellow – Mass Spectrometry

Job Number: 4003036 (Ref.#. 3003) Date Posted: 03/13/2008 Application Deadline: Open Until Filled

An opportunity is available for a Postdoctoral Research Fellow in the laboratory of Dr. John Koomen at Moffitt Cancer Center. This is a post-graduate position in which the individual is responsible for assisting with research activities as well as conducting independent research projects when appropriate under limited supervision. The focus of the proposed research is to develop biomarkers to measure response to therapy and prognosis in cancer patients. The work will start with sequence and post-translational modification analysis of selected targets to examine molecular changes upon drug treatment. These experiments will be conducted using LC-MS/MS, typically with a Dionex nanoLC and an Orbitrap mass spectrometer. After determining peptides and post-translational modifications of biological and clinical interest, quantitative assays will be generated using multiple reaction monitoring on triple quadrupole platforms. The candidate must have experience in mass spectrometry, particularly LC-MS/MS and/or LC- RM, and a completed PhD in MS or a related field. Excellent communication skills and previous experience with the equipment described above will also be required. Excellent verbal and written communication skills are required to work in a multidisciplinary team of research nurses and data managers. The Moffitt Cancer Center is a modern facility on the University of South Florida Campus that conducts research on various aspects of Cancer Biology with emphasis on translational research. It is the third largest Cancer Center in the US based on patient volume. The research environment includes state of the art modern core facilities and pathogen-free modern animal facilities, access to clinical material, etc. Please visit www.moffitt.org/careers to apply online to REQ ID 3003, and send CV, cover letter and three references to Dr. John Koomen at [email protected]. Contact: H. Lee Moffitt Cancer Center & Research Institute 12902 Magnolia Drive Tampa, FL 33612 Web Site: http://www.moffitt.org Online Application: Apply for this position from Employer's website.




http://www.moffitt.org/

http://tbe.taleo.net/NA4/ats/careers/requisition.jsp?org=MOFFITT&cws=1&rid=3003


Through the Lenses of Forum Members

COLLAGE : U T P A L


B

O R A

Dibru Saikhowa: Arindam Adhikari

Aiming High: Mahen Konwar

Up above the Sky: Sasanka Deka


Details about the Northeast India Research Forum

Date of creation of the forum: 13th November 2004 Area: Science and Technology Total number of members till date: 191 Cover page designed by: Mr. Anirban Adhikari Logo designed by: Dr. Manab Sharma

3. Manab Sharma, Ph.D. Dept of Chemistry, Technion-Israel Institute Moderators:

1. Arindam Adhikari, Ph.D. of Technology, Israel. Institute of Surface Chemistry, Royal [email protected]: Institute of Technology, Stockholm, Sweden Email: 4. Rashmi Rekha Devi, Ph.D [email protected]

Scientist, Defence Material & Stores Research & Dev. Establishment, DRDO, 2. Jadab Sharma, Ph.D. Kanpur. Email: Email: [email protected] [email protected]

3. Utpal Borah, Ph.D. 5. Joshodeep Boruwa, Ph.D. Gifu Pharmaceutical University, Japan Fachbereich Chemie, L-940, Universitat

Konstanz, D-78457, Konstanz, Germany Email: [email protected]: [email protected]

4. Ashim J. Thakur, Ph.D. Chemical Science Dept, Tezpur University, 6. Pankaj Bharali, Tezpur, Assam Indian Institute of Chemical Technology, Email: Hyderabad, India. [email protected]

Email: [email protected] Editorial Team of NE Quest 7. Pranjal Saikia 1. Dhanapati Deka, Ph.D. I&PC Division, IICT, Hyderabad, India Reader, School of Energy, Environment and Email: [email protected] reseources, Tezpur University, Assam.

[email protected] 8. Ashim Thakur, Ph.D. Email: 9. Utpal Borah, Ph.D. 2. Tankeswar Nath, Ph.D. Scientist, R&D, Biotechnology, 10. Arindam Adhikari, Ph.D. Jubilant Organosys Ltd. Gajraula, UP, India Email: [email protected]

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NE Quest Volume 2 Issue 1 April 2008

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