Bhabha Atomic Research Center
Mumbai, India

The Bhabha Atomic Research Centre is India's premier nuclear research facility based in Trombay, Mumbai. BARC is a multi-disciplinary research centre with extensive infrastructure for advanced research and development covering the entire spectrum of nuclear science, engineering and related areas.BARC's core mandate is to sustain peaceful applications of nuclear energy, primarily for power generation. It manages all facets of nuclear power generation, from theoretical design of reactors, computerised modelling and simulation, risk analysis, development and testing of new reactor fuel materials, etc. It also conducts research in spent fuel processing, and safe disposal of nuclear waste. Its other research focus areas are applications for isotopes in industries, medicine, agriculture, etc. BARC operates a number of research reactors across the country. Wikipedia.

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Priyadarsini K.I.,Bhabha Atomic Research Center
Current Pharmaceutical Design | Year: 2013

Curcumin, a polyphenolic natural product, exhibits therapeutic activity against a number of diseases, attributed mainly to its chemical structure and unique physical, chemical, and biological properties. It is a diferuloyl methane molecule [1,7-bis (4-hydroxy-3- methoxyphenyl)-1,6-heptadiene-3,5-dione)] containing two ferulic acid residues joined by a methylene bridge. It has three important functionalities: an aromatic o-methoxy phenolic group, α, β-unsaturated β-diketo moiety and a seven carbon linker. Extensive research in the last two decades has provided evidence for the role of these different functional groups in its crucial biological activities. A few highlights of chemical structural features associated with the biological activity of curcumin are: The o-methoxyphenol group and methylenic hydrogen are responsible for the antioxidant activity of curcumin, and curcumin donates an electron/ hydrogen atom to reactive oxygen species. Curcumin interacts with a number of biomolecules through non-covalent and covalent binding. The hydrogen bonding and hydrophobicity of curcumin, arising from the aromatic and tautomeric structures along with the flexibility of the linker group are responsible for the non-covalent interactions. The α, β-unsaturated β-diketone moiety covalently interacts with protein thiols, through Michael reaction. The β-diketo group forms chelates with transition metals, there by reducing the metal induced toxicity and some of the metal complexes exhibit improved antioxidant activity as enzyme mimics. New analogues with improved activity are being developed with modifications on specific functional groups of curcumin. The physico-chemical and structural features associated with some of the biological activities of curcumin and important analogues are summarized in this article. © 2013 Bentham Science Publishers.

Nancharaiah Y.V.,UNESCO-IHE Institute for Water Education | Nancharaiah Y.V.,Bhabha Atomic Research Center | Lens P.N.L.,UNESCO-IHE Institute for Water Education
Microbiology and Molecular Biology Reviews | Year: 2015

In nature, selenium is actively cycled between oxic and anoxic habitats, and this cycle plays an important role in carbon and nitrogen mineralization through bacterial anaerobic respiration. Selenium-respiring bacteria (SeRB) are found in geographically diverse, pristine or contaminated environments and play a pivotal role in the selenium cycle. Unlike its structural analogues oxygen and sulfur, the chalcogen selenium and its microbial cycling have received much less attention by the scientific community. This review focuses on microorganisms that use selenate and selenite as terminal electron acceptors, in parallel to the well-studied sulfate-reducing bacteria. It overviews the significant advancements made in recent years on the role of SeRB in the biological selenium cycle and their ecological role, phylogenetic characterization, and metabolism, as well as selenium biomineralization mechanisms and environmental biotechnological applications. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Priyadarsini K.I.,Bhabha Atomic Research Center
Molecules | Year: 2014

Curcumin, a pigment from turmeric, is one of the very few promising natural products that has been extensively investigated by researchers from both the biological and chemical point of view. While there are several reviews on the biological and pharmacological effects of curcumin, chemistry reviews are comparatively scarcer. In this article, an overview of different aspects of the unique chemistry research on curcumin will be discussed. These include methods for the extraction from turmeric, laboratory synthesis methods, chemical and photochemical degradation and the chemistry behind its metabolism. Additionally other chemical reactions that have biological relevance like nucleophilic addition reactions, and metal chelation will be discussed. Recent advances in the preparation of new curcumin nanoconjugates with metal and metal oxide nanoparticles will also be mentioned. Directions for future investigations to be undertaken in the chemistry of curcumin have also been suggested. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Srinivasu K.,Bhabha Atomic Research Center | Ghosh S.K.,Bhabha Atomic Research Center
Journal of Physical Chemistry C | Year: 2012

Ab initio first-principles calculations were carried out to investigate lithium-dispersed two-dimensional carbon allotropes, viz. graphyne and graphdiyne, for their applications as lithium storage and hydrogen storage materials. The lithiation potentials (vs Li/Li +) and specific capacities in these materials are found to be enhanced considerably as compared to the conventional graphite-based electrode materials. Lithium metal binding to these carbon materials is found to be enhanced considerably and is more than the cohesive energy of lithium. Each lithium atom in these metal-dispersed materials is found to carry nearly one unit positive charge and bind molecular hydrogen with considerably improved adsorption energies. Our calculated hydrogen adsorption enthalpies (-3.5 to -2.8 kcal/mol) are very close to the optimum adsorption enthalpy proposed for ambient temperature hydrogen storage (-3.6 kcal/mol). We have also shown that the band gaps in these planar carbon allotropes can be tuned by varying the number of acetylenic bridging units which will have versatile applications in nanoelectronics. © 2012 American Chemical Society.

Immobilization of phosphate containing high level nuclear wastes within commonly used silicate glasses is difficult due to restricted solubility of P2O5 within such melts and its tendency to promote crystallization. The situation becomes more adverse when sulfate, chromate, etc. are also present within the waste. To solve this problem waste developers have carried out significant laboratory scale research works in various phosphate based glass systems and successfully identified few formulations which apparently look very promising as they are chemically durable, thermally stable and can be processed at moderate temperatures. However, in the absence of required plant scale manufacturing experiences it is not possible to replace existing silicate based vitrification processes by the phosphate based ones. A review on phosphate glass based wasteforms is presented here. © 2012 Elsevier B.V.

Manna P.K.,Bhabha Atomic Research Center | Yusuf S.M.,Bhabha Atomic Research Center
Physics Reports | Year: 2014

Exchange bias and magnetic proximity effects are two novel phenomena that are in the limelight because of their fundamental and technological importance. Since both phenomena are interfacial in origin, we review these together. In the first part of this review, we have discussed the basics of these two phenomena. Subsequently, we have described numerous experimental examples involving a variety of composite magnetic materials and heterostructures. The recent theoretical models of these two interface phenomena have also been described. Finally, we have shed light on an obvious question: can one expect both these phenomena to occur together in any magnetically coupled systemα We conclude that one can enhance the operating temperature of an exchange biased device by exploiting the magnetic proximity effect. © 2013 Elsevier B.V.

Behavioral heterogeneity within a given patient cohort has been a major challenge in clinical practice and is probably most prominently observed in the field of oncology. This has been the prime impetus of the cutting-edge preclinical and clinical research studies over recent times, many of which seek to further stratify patients based on patients' genetic, proteomic, and metabolic profile (the three key components of "-omics" research), in order to select the appropriate therapy according to an individual's best-fit. Data from functional radionuclide imaging particularly that obtained from PET-CT, with regard to characterization of an individual's tumor phenotype, can play a very important role in answering some of the critical decision-making questions on an individual basis. The role of molecular imaging with PET, SPECT, and planar radionuclide technologies is not confined to early response assessment of administered therapeutics (which is its major benefit compared to conventional methods), rather it has a much broader perspective and encompasses multiple steps in decision making steps of patient management. The immense impact of the radionuclide-based molecular imaging techniques on the selection of an appropriate treatment (at initial diagnosis, during therapy, or after therapy) or in defining the tumor biology has been documented and increasingly recognized through both large and small-scale studies. However, there has been relatively less systematic effort towards the development of a successful and definitive clinical model of "personalized cancer medicine" (based on accurate disease triaging on an individual basis) by the medical community that would be suitable for routine adoption. In this paper, an endeavor has been made to explore the potential of this approach and underscore the areas that would require further critical evaluation to make this a reality. © 2013, Discovery Medicine.

Kumar A.,Bhabha Atomic Research Center | Yusuf S.M.,Bhabha Atomic Research Center
Physics Reports | Year: 2015

In this article, we present an in-depth review of the phenomenon of negative magnetization (or magnetization sign reversal) with an up-to-date literature. We have described numerous experimental examples of the phenomenon, involving a variety of magnetically ordered systems, where it does not arise due to diamagnetism. The present review discusses physics principles for the sign reversal of magnetization under the following mechanisms: (a) negative exchange coupling among ferromagnetic sublattices, (b) negative exchange coupling among canted antiferromagnetic sublattices, (c) negative exchange coupling among ferromagnetic/canted-antiferromagnetic and paramagnetic sublattices, (d) imbalance of spin and orbital moments, and (e) interfacial exchange coupling between ferromagnetic and antiferromagnetic phases. We have put forward the roles of crystal structure, crystallite type (single crystal, bulk polycrystalline, thin film, and nanoparticle), lattice defect, electronic or chemical phase separation, magnetic anisotropy, and magnetic exchange interactions in the magnetization reversal. This review validates the mean field theory, given by L. Néel (1948), for an explanation of the negative magnetization under the category (a). We also bring out the necessity of further theoretical work to account for the other categories, (b)-(e). The present review also describes the importance of various magnetization measurement protocols for the occurrence of the magnetization reversal. Finally, we have pointed out the tunability aspect of the phenomenon. We conclude that the practical utilization of this phenomenon in magnetic memory, and magnetocaloric and spin resolving devices might be realized by choosing appropriate and well characterized materials whose compensation temperature can be tuned to room temperature. © 2014 Elsevier B.V.

Kedarnath G.,Bhabha Atomic Research Center | Jain V.K.,Bhabha Atomic Research Center
Coordination Chemistry Reviews | Year: 2013

This review intends to cover the synthesis of both mono- and di-chalcogenides of 2-, 3- and 4-pyridyl and 2-pyrimidyl groups, their spectroscopic and structural studies. The 77Se and 125Te NMR chemical shifts of some pyridyl and pyrimidyl compounds are discussed. Salient structural features of these compounds and their metal complexes are summarized. The utility of these compounds in coordination chemistry, organic synthesis and biology has been described. The role of metal complexes as molecular precursors for the synthesis of metal chalcogenide nano-particles and for deposition of thin films has been included. © 2013 Elsevier B.V.

Rotational dynamics of two organic solutes, rhodamine 110 (R110) and 2,5-dimethyl-1,4-dioxo-3,6-diphenylpyrrolo[3,4-c]pyrrole (DMDPP), has been investigated as a function of temperature in a series of 1-alkyl-3- methylimidazolium ionic liquids (alkyl = ethyl, butyl, hexyl, and 2-hydroxyethyl) containing tris(pentafluoroethyl)trifluorophosphate (FAP) anion. The present study has been essentially undertaken to examine the influence of specific interactions on the rotation of cationic (R110) and neutral (DMDPP) solutes in this new class of ionic liquids. Analysis of the results using the Stokes-Einstein-Debye hydrodynamic theory indicates that the rotational dynamics of R110 is closer to the stick boundary condition whereas the dynamics of DMDPP is described by the slip boundary condition. The observed slow dynamics of R110 has been rationalized on the basis of specific interactions between the cationic solute and the FAP anion of the ionic liquid. It has also been noticed that the rotational dynamics of DMDPP is slower by 30% in 1-(2-hydroxyethyl)-3- methylimidazolium FAP compared to that observed in its ethyl counterpart, which is assimilated in terms of hydrogen bonding interactions between the carbonyl groups of the solute and the hydroxyl group of the imidazolium cation. © 2010 American Chemical Society.

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