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排序方式: 共有148条查询结果,搜索用时 15 毫秒
81.
P. Govindan S. Sukumar K. S. Vijayan G. Santhosh Kumar S. Ganesh Pradeep Kumar Sharma K. Dhamodharan R. V. Subba Rao M. Venkataraman R. Natarajan 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(1):151-156
A novel method has been developed for recovery of plutonium and uranium from carbonate wash solutions generated during solvent
wash process involved in the reprocessing of high burn up FBTR fuel. The proposed method involves a selective coprecipitation
of Pu and U by adding ammonium hydroxide to the pre acidified carbonate wash solution. Substantial removal of DBP by successive
steps of coprecipitation, completely eliminates the possibility of undesired solid formation which is mainly due to the presence
of high content of DBP. By adopting this method, an excellent decontamination factor for DBP has been achieved without any
crud/solid formation. Phosphate content in the final oxide product meets the product specifications. Flowsheet condition necessary
for the recovery process for plutonium from the aqueous carbonate solution is formulated and adopted in the CORAL facility. 相似文献
82.
Supriyo Bhattacharya Govindan Subramanian Spencer Hall Jianping Lin Abdelazize Laoui Nagarajan Vaidehi 《Journal of computer-aided molecular design》2010,24(8):659-674
The 41 amino acid neuropeptide, corticotropin-releasing factor (CRF) and its associated receptors CRF1-R and CRF2-R have been targeted for treating stress related disorders. Both CRF1-R and CRF2-R belong to the class B G-protein coupled receptors for which little information is known regarding the small molecule antagonist
binding characteristics. However, it has been shown recently that different non-peptide allosteric ligands stabilize different
receptor conformations for CRF1-R and hence an understanding of the ligand induced receptor conformational changes is important in the pharmacology of ligand
binding. In this study, we modeled the receptor and identified the binding sites of representative small molecule allosteric
antagonists for CRF1-R. The predicted binding sites of the investigated compounds are located within the transmembrane (TM) domain encompassing
TM helices 3, 5 and 6. The docked compounds show strong interactions with H228 on TM3 and M305 on TM5 that have also been
implicated in the binding by site directed mutation studies. H228 forms a hydrogen bond of varied strengths with all the antagonists
in this study and this is in agreement with the decreased binding affinity of several compounds with H228F mutation. Also
mutating M305 to Ile showed a sharp decrease in the calculated binding energy whereas the binding energy loss on M305 to Leu
was less significant. These results are in qualitative agreement with the decrease in binding affinities observed experimentally.
We further predicted the conformational changes in CRF1-R induced by the allosteric antagonist NBI-27914. Movement of TM helices 3 and 5 are dominant and generates three degenerate
conformational states two of which are separated by an energy barrier from the third, when bound to NBI-27914. Binding of
NBI-27914 was predicted to improve the interaction of the ligand with M305 and also enhanced the aromatic stacking between
the ligand and F232 on TM3. A virtual ligand screening of ~13,000 compounds seeded with ~350 CRF1-R specific active antagonists performed on the NBI-27914 stabilized conformation of CRF1-R yielded a 44% increase in enrichment compared to the initially modeled receptor conformation at a 10% cutoff. The NBI-27914
stabilized conformation also shows a high enrichment for high affinity antagonists compared to the weaker ones. Thus, the
conformational changes induced by NBI-27914 improved the ligand screening efficiency of the CRF1-R model and demonstrate a generalized application of the method in drug discovery. 相似文献
83.
More than 99% of the species that ever existed on the surface of the Earth are now extinct and their extinction on a global scale has been a puzzle. One may think that a species under an external threat may survive in some isolated locations leading to the revival of the species. Using a general model we show that, under a common external forcing, the species with a quadratic saturation term first undergoes spatial synchronization and then extinction. The effect can be observed even when the external forcing acts only on some locations provided the dynamics contains a synchronizing term. Absence of the quadratic saturation term can help the species to avoid extinction. 相似文献
84.
T. E. Govindan 《Stochastics An International Journal of Probability and Stochastic Processes》2013,85(2):139-154
In this paper, we initiate a study on stochastic neutral partial functional differential equations in a real separable Hilbert space. Our goal here is to study the existence and uniqueness of a mild solution of this class of equations and also the exponential stability of the moments of a mild solution as well as its sample paths. The results obtained here generalize the main results from [Taniguchi, Stochastics and Stochastics Reports, 53, (1995) 41–52], [Taniguchi, Stochastic Analysis and Applications, 16, (1998) 965–975] and [Liu and Truman, Statistics Probability Letters, 50, (2000) 273–278]. An example is given to illustrate the theory. 相似文献
85.
Kuzhandaivel Hemalatha Basha Summaya Banu Charles Immanuel David Raju Nandhakumar Singaravelu Usha Sivalingam Nallathambi Karthick 《Journal of fluorescence》2021,31(4):1041-1053
Journal of Fluorescence - The thiazole based Schiff base 2-hydroxy-1-naphthaldehyde-2-amino thiazole (receptor1) was synthesized through a single step process and characterized by spectroscopic and... 相似文献
86.
87.
88.
Govindan Rangarajan 《Pramana》1997,48(1):129-142
There exist several standard numerical methods for integrating ordinary differential equations. However, if one is interested
in integration of Hamiltonian systems, these methods can lead to wrong results. This is due to the fact that these methods
do not explicitly preserve the so-called ‘symplectic condition’ (that needs to be satisfied for Hamiltonian systems) at every
integration step. In this paper, we look at various methods for integration that preserve the symplectic condition. 相似文献
89.
P. Govindan K. S. Vijayan G. Santhosh Kumar V. Vijayakumar M. Venkataraman R. Natarajan 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(1):307-313
A method has been developed for final purification of plutonium from uranium and fission products of high beta gamma activity. This method involves selection of a suitable ion exchange resin for the purification of plutonium in order to deliver a quality PuO2 product. The effect of the concentration of uranium and plutonium, effect of increased loading of uranium and number of bed volumes for effective washing, which are some of the parameters that generally affect the recovery and purification of plutonium were investigated. An excellent decontamination factor for fission products has been achieved by this anion exchange process which in turn delivered an excellent PuO2 product quality in terms of purity and associated beta gamma activity with low personnel radiation exposure. 相似文献
90.