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141.
Anees A. Ansari A. Kaushik P.R. Solanki B.D. Malhotra 《Electrochemistry communications》2008,10(9):1246-1249
Cholesterol oxidase (ChOx) has been immobilized onto sol–gel derived nano-structured cerium oxide (NS-CeO2) film deposited on indium-tin-oxide (ITO) coated glass substrate. Phase identification of sol–gel NS-CeO2 film carried out using X-ray diffraction (XRD) yields reflection peak at 29.4° corresponding to (1 1 1) plane with oriented crystallite (34 nm) along c-axis normal to the substrate. Electrochemical studies reveal that NS-CeO2 provides electroactive surface for the loading of ChOx and enhances electron transfer rate in the ChOx/NS-CeO2/ITO bioelectrode. The low value of Michaelis–Menten constant (Km) obtained as 2.08 mM indicates enhanced ChOx affinity to cholesterol. The observed results show application of sol–gel derived NS-CeO2 for biosensing without any functionalization. 相似文献
142.
Kaushik Ghosh Pramod KumarNidhi Tyagi Udai P. SinghNidhi Goel Ajanta ChakrabortyPartha Roy Maria Camilla Baratto 《Polyhedron》2011,30(16):2667-2677
The copper complexes [Cu(Pyimpy)(H2O)](ClO4)2 (1), [Cu(Pyimpy)2](ClO4)2 (2), [Cu(Pyimpy)(Cl)2]·2H2O (3·2H2O), [Cu(Pyimpy)(N3)(ClO4)]2 (4) and [Cu(Pyimpy)(SCN)(ClO4)]2 (5) were synthesized and characterized by spectroscopic techniques, crystal structures and electrochemical studies (Pyimpy: (2-((2-phenyl-2-(pyridin-2-l)hydrazono)methyl)pyridine)). The superoxide scavenging activity of the two water soluble complexes 1 and 3 was examined. DNA interaction studies by UV-Vis absorption spectral changes during a titration experiment indicated the generation of new species. These small molecule SOD mimics exhibited excellent DNA cleavage activity in the presence of H2O2 as well as 2-mercaptoethanol. Complexes 1-5 exhibited better cytotoxicity compared to CuCl2·2H2O and the ligand Pyimpy, and showed more potency than cisplatin for MCF-7, PC-3 and HEK-293 cells. Complex 3 exhibited the highest potency for MCF-7, PC-3 and HEK-293 cells compared to the other complexes. 相似文献
143.
In this investigation, a prototype model of the solar adsorption refrigeration system was constructed and its performance was evaluated with different mass ratios of adsorbents in the laboratory for possible field application. The main components of the solar-driven cooling system were vacuum tube collector, adsorption bed, condenser, evaporator, chilling chamber, and temperature data logger. The experimental study was conducted to analyze the performance of solar cooling unit using different mass ratios of activated carbon–methanol from 0.250 to 2.50. A minimum cooling temperature of 12.2 °C was obtained with the manually prepared activated carbon–methanol with mass ratio of 1.00. The cooling coefficient of performance and specific cooling potential was also evaluated from performance calculations. 相似文献
144.
Kaushik Das 《Journal of solution chemistry》1989,18(11):1085-1093
The limiting partial molar volumes of alkali metal halides in water and some other protic solvents have been dissected into individual ionic contributions. The extra-thermodynamic procedure employed assumes independent contributions of ion-solvent and solvent-solvent interactions to this property. The resulting parameters are found to be chemically reasonable and consistent with the molecular properties of the solvents. The limiting partial molar volume of the hydrogen ion has been calculated to be –4.2 cm3-mol–1 in water at 25°C. Analysis of data for aqueous solutions from 0 to 50°C permits the evaluation of the energy change associated with the transfer of a water molecule from the bulk to the hydration zone. Results from the present work are compared with those obtained from the scaled particle theory. 相似文献
145.
The N,N′-disubstituted urea derivatives such as amino acid hydantoins and dihydrouracil derivatives were prepared starting from natural and unnatural amino acid esters using dibutylphosphate (DBP). During the attempted synthesis of N-heterocycles with larger than six-membered rings containing the N,N′-disubstituted urea functionalities, three unexpected products namely squamolone, N-methyl pyrrolidine-2-one, and diketopiperazine were isolated. 相似文献
146.
Mariam S. Degani Manoj D. Kakwani Nutan H. Palsule Desai Ranjeet Bairwa 《Monatshefte für Chemie / Chemical Monthly》2012,13(2):461-465
Abstract
A wide variety of carbonyl compounds can be transformed to their corresponding cyanohydrins in a single step using a dimethyl sulfoxide (DMSO)–water system in excellent yields (75–94%). The major advantages of this system are that the reaction conditions are mild and neutral; the reaction proceeds without catalyst and gives the corresponding cyanohydrins in short time (15–120 min). 相似文献147.
The quantum dynamics of the evolution of a system of a few coupled nonlinear oscillators is studied. The spectral entropy and the quantal information entropy, as well as their correlation functions, are computed and used to identify distinctive phases of the evolution. The two entropy functions lead to similar conclusions. It appears that adiabatic switching of the nonlinear interaction does not affect the nature of the short time dynamics but affects the dynamics over intermediate time scales. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 相似文献
148.
Kaushik Das 《Journal of solution chemistry》1988,17(4):327-336
Single ion activities in aqueous H2SO4 have been calculated from the mean ionic activity coefficients of H2SO4, the solubilities of PbSO4 and the degrees of the second dissociation of H2SO4 in these solutions by employing a new extra-thermodynamic assumption. The hydrogen ion activities thus obtained are compared with the corresponding acidity function values based on different classes of acid-base indicators. 相似文献
149.
150.
Change point hazard rate models arise in many life time data analysis, for example, in studying times until the undesirable side effects occur in clinical trials. In this paper we propose a general class of change point hazard model for survival data. This class includes and extends different types of change point models for survival data, e.g. cure rate model and lag model. Most classical approach develops estimates of model parameters, with particular interest in change point parameter and often the whole hazard function, but exclusively in terms of asymptotic properties. We propose a Bayesian approach, avoiding asymptotics and provide inference conditional upon the observed data. The proposed Bayesian models are fitted using Markov chain Monte Carlo method. We illustrate our proposed methodology with an application to modeling life times of the printed circuit board. 相似文献