排序方式: 共有52条查询结果,搜索用时 0 毫秒
41.
Anil Kumar Shukla Bishal Kumar Singh Sanjukta Patra Vikash Kumar Dubey 《Applied biochemistry and biotechnology》2010,160(8):2208-2218
Leishmaniasis has been ignored for many years mainly because it plagues remote and poor areas. However, recently, it has drawn
attention of several investigators, and active research is going on for antileishmanial drug discovery. The current available
drugs have high failure rates and significant side effects. Recently, liposomal preparations of amphotericin B are available
and have proved to be a better drug, but they are very expensive. Miltefosine is one of the few orally administered drugs
that are effective against Leishmania. However, it has exhibited teratogenicity, hence, should not be administered to pregnant women. Thus, the search for novel
and improved antileishmanial drugs continue. A rational approach to design and develop new antileishmanials can be to identify
several metabolic and biochemical differences between host and parasite that can be exploited as drug target. Moreover, many
natural products also have significant antileishmanial activity and are yet to be exploited. In the current review, we aim
to bring together various drug targets of Leishmania, recent development in the field, future prospects, and hope in the area. 相似文献
42.
Vikash Sewram Jerald J. Nair Dulcie A. Mulholland Mark W. Raynor 《Journal of separation science》1995,18(6):363-366
Open tubular supercritical fluid chromatography (SFC) with carben dioxide as the mobile phase has been investigated for the separation of four triterpene acids, two of which were structural isomers. These compounds, isolated from Dysoxylum pettigrewianum (Meliaceae), were chromatographed on three stationary phases with different selectivities. 30%-biphenylmethylpolysiloxane and polyethylene glycol (Carbowax 20M) phases exhibited poor chromatographic selectivity for the compounds. The separation was improved by employing the shape selectivity of a liquid crystalline biphenylcarboxylate ester polysiloxane and utilizing simultaneous temperature and pressure programming. The elution order was explained on the basis of the molecular structures of the triterpene acids, and their interaction with the liquid crystal phase. 相似文献
43.
Pushpa R. Paudel Vikash Kaphle Drona Dahal Raj Kishen Radha Krishnan Björn Lüssem 《Advanced functional materials》2021,31(3):2004939
Organic electrochemical transistors (OECTs) operate at very low voltages, transduce ions into electronic signals, and reach extremely large transconductance values, making them ideally suited for bio-sensing applications. However, despite their promising performance, the dependence of their maximum transconductance on device geometry and applied voltages are not correctly captured by current capacitive device models. Here, current scaling laws are revised in the light of a recently developed 2D device model that adequately accounts for drift and diffusion of ions inside the polymer channel. It is shown that the maximum transconductance of the devices is found at the transition between the depletion and accumulation region of the transistors, which as well provides an explanation for the observed shift of the transconductance peak with geometric dimensions and the drain potential. Overall, the results provide a better understanding of the working mechanisms of OECTs, and facilitate design rules to optimize OECT performance further. 相似文献
44.
Vikash Ranjan Thomas Begou Scott Little Robert W. Collins Sylvain Marsillac 《Progress in Photovoltaics: Research and Applications》2014,22(1):77-82
Cu(In,Ga)Se2 (CIGS) thin films co‐evaporated by 1‐stage, 2‐stage, and 3‐stage processes have been studied by spectroscopic ellipsometry (SE). The disappearance of a Cu2‐xSe optical signature, detected by real time SE during multistage CIGS, has enabled precise endpoint control. Band gap energies determined by SE as depth averages show little process variation for fixed [Ga]/([In] + [Ga]) atomic ratio, whereas their broadening parameters decrease with increasing number of stages, identifying successive grain size enhancements. Refined SE analysis has revealed band gap profiling only for 3‐stage CIGS. Solar cells incorporating these absorbers have yielded increased efficiencies in correlation with phase control, grain size, and band gap profiling. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
45.
Subhash Sharma Vikash Singh Om Parkash R. K. Dwivedi 《Applied Physics A: Materials Science & Processing》2013,112(4):975-984
An effort has been made to synthesize solid solution of a composition with x=0.05 in the system (1?x)PbZr0.52Ti0.48O3–(x)BiFeO3 by the sol–gel method. XRD patterns of the pure PZT and BFO modified PZT samples have shown single phase formation. The effects of substitution of BFO on dielectric properties of PZT have been studied in the frequency range 10 Hz to 100 kHz and temperature range from RT to 773 K. The density was optimized by sintering the BFO modified PZT samples at different temperatures in four batches, S1, S2, S3 and S4. P–E hysteresis loop measurements for all the samples have shown almost saturated polarization. It has been observed that sample S2, sintered at 950 °C, exhibits superior dielectric properties of the four samples. The occurrence of weak ferromagnetism, observed in the M–H hysteresis loop, indicates coupling between ferroelectricity and magnetism. Impedance analysis has revealed that all the samples, sintered at different temperatures, have a different grain resistance. A large change in ac conductivity around T c has been observed in all the samples. 相似文献
46.
Vikash Mishra Ishan Mohanty Mayank R. Patel 《International Journal of Polymer Analysis and Characterization》2015,20(6):504-513
A series of novel waterborne UV-curable polyurethane dispersions were synthesized from castor oil, IPDI, DMPA, and HEMA by the acetone process. The prepared UV-PUD was mixed with three different monomers and characterized for the parameters relevant to the study by physical, spectroscopic, and chemical methods. The effect of monomer type on the physicochemical and thermal properties of UV-PUDs revealed that the number of unsaturated groups present in the monomer had a pronounced effect on physicochemical, mechanical, and thermal properties. The combination of renewable resource and environmentally compliant technology give these UV-PUDs potential scope in coating applications. 相似文献
47.
48.
49.
50.
Santhanam G Linderman MD Gilja V Afshar A Ryu SI Meng TH Shenoy KV 《IEEE transactions on bio-medical engineering》2007,54(11):2037-2050
Chronically implanted electrode arrays have enabled a broad range of advances in basic electrophysiology and neural prosthetics. Those successes motivate new experiments, particularly, the development of prototype implantable prosthetic processors for continuous use in freely behaving subjects, both monkeys and humans. However, traditional experimental techniques require the subject to be restrained, limiting both the types and duration of experiments. In this paper, we present a dual-channel, battery-powered neural recording system with an integrated three-axis accelerometer for use with chronically implanted electrode arrays in freely behaving primates. The recording system called HermesB, is self-contained, autonomous, programmable, and capable of recording broadband neural (sampled at 30 kS/s) and acceleration data to a removable compact flash card for up to 48 h. We have collected long-duration data sets with HermesB from an adult macaque monkey which provide insight into time scales and free behaviors inaccessible under traditional experiments. Variations in action potential shape and root-mean square (RMS) noise are observed across a range of time scales. The peak-to-peak voltage of action potentials varied by up to 30% over a 24-h period including step changes in waveform amplitude (up to 25%) coincident with high acceleration movements of the head. These initial results suggest that spike-sorting algorithms can no longer assume stable neural signals and will need to transition to adaptive signal processing methodologies to maximize performance. During physically active periods (defined by head-mounted accelerometer), significantly reduced 5-25-Hz local field potential (LFP) power and increased firing rate variability were observed. Using a threshold fit to LFP power, 93% of 403 5-min recording blocks were correctly classified as active or inactive, potentially providing an efficient tool for identifying different behavioral contexts in prosthetic applications. These results demonstrate the utility of the HermesB system and motivate using this type of system to advance neural prosthetics and electrophysiological experiments. 相似文献