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111.
Divya Chalapathi Amrendra Kumar Pratik Behera Shijulal Nelson Sathi Rajaram Swaminathan Chandrabhas Narayana 《Molecules (Basel, Switzerland)》2022,27(20)
Protein misfolding and aggregation play a significant role in several neurodegenerative diseases. In the present work, the spontaneous aggregation of hen egg-white lysozyme (HEWL) in an alkaline pH 12.2 at an ambient temperature was studied to obtain molecular insights. The time-dependent changes in spectral peaks indicated the formation of β sheets and their effects on the backbone and amino acids during the aggregation process. Introducing iodoacetamide revealed the crucial role of intermolecular disulphide bonds amidst monomers in the aggregation process. These findings were corroborated by Molecular Dynamics (MD) simulations and protein-docking studies. MD simulations helped establish and visualize the unfolding of the proteins when exposed to an alkaline pH. Protein docking revealed a preferential dimer formation between the HEWL monomers at pH 12.2 compared with the neutral pH. The combination of Raman spectroscopy and MD simulations is a powerful tool to study protein aggregation mechanisms. 相似文献
112.
S. Sundar Pethaiah G. Paruthimal Kalaignan G. Sasikumar M. Ulaganathan V. Swaminathan 《Journal of Solid State Electrochemistry》2013,17(11):2917-2925
Nano-catalyzed membrane with different platinum (Pt) catalyst loadings (0.25 to 1 mg cm?2) was investigated for proton exchange membrane fuel cell applications, and the Pt loading on the Nafion membrane was prepared by non-equilibrium impregnation reduction method. The prepared catalyzed membranes were subjected to various characterisations, namely, X-ray diffraction, high-resolution scanning electron microscopy (HRSEM) with energy-dispersive X-ray, cyclic voltammetry, polarisation and electrochemical impedance spectroscopy. The polycrystalline fcc cubic structure and the particle size of Pt catalyst were estimated by X-ray diffraction analysis. The membrane with 0.4 mg cm?2 of Pt loading exhibits a favourable surface morphology which is confirmed by HRSEM image. Electrochemical investigations were clearly evident that the uniform distributions of Pt particles with fine pores on Nafion membrane facilitated the three-phase boundary which leads to a better cell performance. Electrochemical impedance spectroscopy demonstrated that the cell constructed using 0.4 mg cm?2 of platinum-loaded membrane has lower resistance than the other Pt loading. 相似文献
113.
B. Saha K. Swaminathan C. R. Venkatasubramani P. R. Vasudeva Rao 《Journal of Radioanalytical and Nuclear Chemistry》1996,214(1):17-27
The extraction of Ce (IV) by di-(2-ethylhexyl)-phosphoric acid (HDEHP) has been studied as a function of nitric acid concentration. Using the distribution coefficient data, the optimum conditions for recovery of Ce (IV) from nitric acid medium were arrived at. Under the conditions employed for Ce(IV), a small percentage of Ru was also found to be extracted. Cerium could be selectively stripped from the organic phase with 8M HNO3/30% H2O2 solution. This procedure led to the recovery of144Ce free of106Ru. Based on the solvent extraction data, an extraction-chromatographic procedure employing HDEHP (40% w/w) loaded on Amberlite XAD-7 as the stationary phase was developed for the isolation of pure, carrier-free144Ce from the spent fuel solution. 相似文献
114.
The divinyl carbinols and furnished octalinols and respectively on treatment with base. 相似文献
115.
Biosorption of copper (II) and cadmium (II) by live Phanerochaete chrysosporium immobilized by growing onto polyurethane foam material in individual packed bed columns over two successive cycles of sorption–desorption
were investigated in this study. Initial pH and concentrations of the metals in their respective solutions were set optimum
to each of those: 4.6 and 35 mg·l−1 in case of copper and 5.3 and 11 mg·l−1 for cadmium. The breakthrough curves obtained for the two metals during sorption in both the cycles exhibited a constant
pattern at various bed depths in the columns. The maximum yield of the columns in removing these metals were found to be,
respectively, 57% and 43% for copper and cadmium indicating that copper biosorption by the immobilized fungus in its column
was better than for cadmium. Recovery values of the sorbed copper and cadmium metals from the respective loaded columns by
using 0.1 N HCl as eluant was observed to be quite high at more than 65% and 75%, respectively, at the end of desorption in
both the cycles. Breakthrough models of bed-depth service time, Adams–Bohart, Wolborska, and Clark were fitted to the experimental
data on sorption of copper and cadmium in the columns, and only the Clark model could fit the sorption performance of the
columns well over the entire range of ratios of concentrations of effluent to influent, i.e., C/C
0 for both copper and cadmium biosorption. The kinetic coefficients of mass transfer and other suitable parameters in the system
were determined by applying the experimental data at C/C
0 ratios lower than 0.5 to the other three models. 相似文献
116.
Varghese B Cheong FC Sindhu S Yu T Lim CT Valiyaveettil S Sow CH 《Langmuir : the ACS journal of surfaces and colloids》2006,22(19):8248-8252
We report a simple and effective approach to organize micron- and submicron-sized particles in a size selective manner. This approach utilizes the template assisted directed self-assembly technique. A topographically patterned photoresist surface is fabricated and used to create an ordered array of colloidal particles from their aqueous suspensions. Assembly of particles on this template is then achieved by using a conventional spin coating technique. Feasibility of this technique to form a large area of patterned particle assemblies has been investigated. To arrange the particles on the template, the physical confinement offered by the surface topography must overcome a joint effect of centrifugal force and the hydrophobic nature of the photoresist surface. This concept has been extended to the size selective sorting of colloidal particles. The capability of this technique for sorting and organizing colloidal particles of a particular diameter from a mixture of microspheres is demonstrated. 相似文献
117.
Lactic acid fermentation in cell-recycle membrane bioreactor 总被引:2,自引:0,他引:2
Traditional lactic acid fermentation suffers from low productivity and low product purity. Cell-recycle fermentation has become
one of the methods to obtain high cell density, which results in higher productivity. Lactic acid fermentation was investigated
in a cell-recycle membrane bioreactor at higher substrate concentrations of 100 and 120 g/dm3. A maximum cell density of 145 g/dm3 and a maximum productivity of 34 g/(dm3…h) were achieved in cell-recycle fermentation. In spite of complete consumption of substrate, there was a continuous increase
in cell density in cell-recycle fermentation. Control of cell density in cell-recycle fermentation was attempted by cell bleeding
and reduction in yeast extract concentration. 相似文献
118.
The radiative and Forster type of energy transfer processes in a dye mixture laser of 7-diethylamino-4-methyl coumarin (donor) and fluorescein disodium salt (acceptor) under nitrogen laser pumping were investigated. The Forster transfer rate calculated from the absorption and emission spectra of acceptor and donor is 1.3 × 1011 liter mole?1sec?1. The gain of acceptor at 550 nm was measured for acceptor concentrations NA from 10?3M to 3 × 10?3M for a fixed ratio F = 1 of donor to acceptor concentrations at different pump powers. The results agreed with the rate equation model proposed for the dye mixture laser. The radiative rate constant calculated from these results is 3.1 × 1010 liter mole?1sec?1. Numerical simulation of the rate equations showed that the acceptor reaches peak emission with a time lag of 3 ns with respect to the donor peak emission for F = 0.998, NA = 10?5M. This time lag decreases with increasing NA and becomes zero for NA = 10?1M, F = 0.048. 相似文献
119.
An n-by-n real matrix A enjoys the “leading implies all” (LIA) property, if, whenever D is a diagonal matrix such that A+D has positive leading principal minors (PMs), all PMs of A are positive. Symmetric and Z-matrices are known to have this property. We give a new class of matrices (“mixed matrices”) that both unifies and generalizes these two classes and their special diagonal equivalences by also having the LIA property. “Nested implies all” (NIA) is also enjoyed by this new class. 相似文献
120.
Richard Montgomery Vidya Swaminathan Mikhail Zhitomirskii 《Journal of Fixed Point Theory and Applications》2008,3(2):353-378
A standard method for resolving a plane curve singularity is the method of blow-up. We describe a less-known alternative method
which we call prolongation, in honor of Cartan’s work in this direction. This method is known to algebraic geometers as Nash
blow-up. With each application of prolongation the dimension of the ambient space containing the new “prolonged” singularity
increases by one. The new singularity is tangent to a canonical plane field on the ambient space. Our main result asserts
that the two methods, blow-up and prolongation, yield the same resolution for unibranched singularities. The primary difficulties
encountered are around understanding the prolongation analogues of the exceptional divisors from blow-up. These analogues
are called critical curves. Most of the critical curves are abnormal extremals in the sense of optimal control theory as it
applies to rank 2 distributions (2 controls).
Dedicated to V. I. Arnol’d and his creative force 相似文献