排序方式: 共有38条查询结果,搜索用时 15 毫秒
1.
Roopa K. P. Keshavamurthy K. Mahesh B. Veena K. P. Shankara B. S. Basavaiah K. 《Journal of Applied Spectroscopy》2022,89(4):809-818
Journal of Applied Spectroscopy - Three simple, sensitive, precise, and rapid spectrophotometric methods are developed and optimized for the assay of vardenafil in pharmaceutical formulations. The... 相似文献
2.
J. Shankara Narayanan C. Anjalidevi V. Dharuman 《Journal of Solid State Electrochemistry》2013,17(4):937-947
Development of nonenzymatic glucose sensors with high reproducibility and stability is an urgent need to reduce cost of regular diabetic monitoring. Here, we have fabricated ruthenium dioxide–poly(vinyl chloride)–Nafion (RuO2–PVC–Nafion) composite for direct glucose sensing in sodium hydroxide and phosphate buffer nonenzymatically for the first time. The restricted activity of the RuO2–PVC film electrode in alkaline pH is extended to neutral pH using Nafion as an outer membrane, which reduces the distance between Ru active sites by bridging effect and improves the electrode stability. The catalytic rate, measured in terms of change of RuO2 resistance, is similar irrespective of the medium for the high temperature annealed RuO2 (700 °C), whereas the low temperature annealed RuO2 (300 °C) is highly sensitive for the change in the pH of the solution. This is revealed by observing large Michaelis–Menten kinetic constant K M for the RuO2 (700 °C) than the low temperature annealed RuO2 (300 °C) due to effective increase in the catalytic active sites similar to oxygen evolution reaction. Contrast to this, the buffer solution does not influence significantly the apparent K M observed for RuO2 (300 °C) and has greater impact on the high temperature 500 and 700 °C annealed RuO2 samples. Cyclic voltammetry, chrono amperommetry, and electrochemical impedance spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction techniques are used for characterization of the sensor behavior. The RuO2–PVC–Nafion senses glucose selectively in the presence of potential interferences like fructose, galactose, mannose, sucrose, starch, uric acid, ascorbic acid, dopamine, and catechol in NaOH and phosphate buffer. Glucose sensing in the blood serum of the diabetic and nondiabetic patients is made. The results suggest that the RuO2–PVC–Nafion is a promising candidate for the development of nonenzymatic glucose sensors. 相似文献
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We consider the analytic continuation of the commutator[q
m, pn for values of m,n positive integers. This is carried out both in the Moyal algebra and the operator algebra. 相似文献
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A formalism is developed which admits particles faster than light and reference frames faster than light and as fast as light. It is fully consistent with the physical principles of special relativity. The necessity of introducing imaginary quantities does not arise. It does not encounter any difficulties with the principle of causality if it is reasonably interpreted.Dedicated to Prof. E. C. G. Sudarshan, in honor of his receipt of the Padmabushan Award. 相似文献
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M. D. Srinivas M. S. Sriram T. S. Shankara 《International Journal of Theoretical Physics》1972,5(4):263-273
Sudarshan's semi-classical treatment of correlation functions is applied to the study of quantum corrections to the Van Hove function. In its generalised form, it enables one to choose the best correlation function for a given potential. Higher-order correlations are also sketched briefly and the details are similar to those considered by Oppenheim and Bloom. 相似文献
7.
In this contribution, we have studied structural and photophysical properties of aggregated CdS quantum dots (QDs) capped with 2-mercaptoethanol in aqueous medium. The hydrodynamic diameter of the nanostructures in aqueous solution was found to be approximately 160 nm with the dynamic light scattering (DLS) technique, which is in close agreement with atomic force microscopy (AFM) studies (diameter approximately 150 nm). However, the UV-vis absorption spectroscopy, powder X-ray diffraction (XRD), and transmission electron microscopy (TEM) studies confirm the average particle size (QD) in the nanoaggregate to be 4.0 +/- 0.5 nm. The steady-state and time-resolved photoluminescence studies on the QDs further confirm preservation of electronic band structure of the QDs in the nanoaggregate. To study the nature of the nanoaggregate we have used small fluorescent probes, which are widely used as biomolecular ligands (2,6-p-toluidinonaphthalene sulfonate (TNS) and Oxazine 1), and found the pores of the aggregate to be hydrophobic in nature. The significantly large spectral overlap of the host quantum dots (donor) with that of the guest fluorescent probe Oxazine 1 (acceptor) allows us to carry out F?rster resonance energy transfer (FRET) studies to estimate average donor-acceptor distance in the nanostructure, found to be approximately 25 Angstrom. The quantum dot aggregate and the characterization techniques reported here could have implications in the future application of the QD-nanoaggregate as host of small ligand molecules of biological interest. 相似文献
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Langmuir-Blodgett monolayer films of C60-didodecyloxybenzene dyad, with a C60 acceptor and didodecyloxybenzene donor, exhibit rectification with high rectification ratios of 87-158 at 3 V. 相似文献
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Direct conjugation of semiconductor nanocrystals to a globular protein to study protein-folding intermediates 总被引:2,自引:0,他引:2
Sarkar R Narayanan SS Pålsson LO Dias F Monkman A Pal SK 《The journal of physical chemistry. B》2007,111(42):12294-12298
In this Article, we study the development of semiconductor nanocrystals (quantum dots of average diameter less than 2 nm) directly conjugated to a transporter protein human serum albumin (HSA) as fluorescent biological labels. F?rster resonance energy transfer (FRET) from the amino acid tryptophan (Trp214) to quantum dot in HSA is monitored to follow the local and global changes in the protein structure during thermal unfolding and refolding processes. This study is likely to attract widespread attention as a powerful tool for the study of protein folding. 相似文献
10.
Spherical fractal aggregates of approximately 10 microm were formed from a pi-electronic amphiphile, C(60)-didodecyloxybenzene dyad when extracted from THF into water, necessitating a critical dielectric constant epsilon > or =30 in binary THF-water mixtures. Molecular dynamics simulations revealed the unit cluster to such a form involves an aggregation number approximately 90 with predominant soft associative molecular interactions which corroborated the octadecahedral model proposed for the cluster growth. 相似文献