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101.
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
102.
Free vibration of nonhomogeneous nanobeams based on nonlocal Timoshenko beam theory has been studied using boundary characteristic orthogonal polynomial functions in the Rayleigh–Ritz method. Orthogonal polynomial functions satisfying essential boundary conditions have been generated with the help of Gram–Schmidt Process. Nonhomogeneity of nanobeams is assumed to arise due to linear and quadratic variations in Young’s modulus and density of the nanobeams with space coordinate. The lowest three frequency parameters of nanobeams subjected to different boundary conditions have been computed for various values of nonhomogeneous parameters to demonstrate the effect of each parameters on the frequency parameters. A detailed investigation has been reported for all the possible cases of variations in Young’s modulus and density to analyze the numerical results for different scaling effect parameters and four types of boundary conditions. Present results are compared with the results in special cases and are found to be in good agreement. 相似文献
103.
Regio- and stereoselective cycloaddition of β-nitroacrylates with electron deficient cyclohexa-2,4-dienones leading to highly functionalised bicyclo[2.2.2]octanes having the β-nitroester group and their transformation to bicyclo[2.2.2]octanes having β-aminoester functionality is described. 相似文献
104.
The rate of hydrolysis of title schiff bases was studied in the pH range 4–13 in 10% dioxanewater system, CTAB, NaLS micellar solutions. The hydrolysis was found to be due to ‘water’ and ‘hydroxide’ reactions and hence the rate constants in different pH were computed and analyzed with an intermediate involving a water molecule being positioned with the help of 2-OH group and the thiazolyl C–N pi bond. The ‘hydroxide’ reaction was due to a direct nucleophilic attack of hydroxide ion at the aldimine linkage of the reactant. The influence of cationic and anionic micelles supports the mechanistic picture in the entire pH range. 相似文献
105.
M. Jayakannan Joost L. J. Van Dongen Girish Ch. Behera S. Ramakrishnan 《Journal of polymer science. Part A, Polymer chemistry》2002,40(24):4463-4476
An AB2 monomer, 1‐(2‐hydroxyethoxy)‐3,5‐bis‐(methoxymethyl)‐2,4,6‐trimethylbenzene, was synthesized from mesitol and melt‐polycondensed in the presence of an acid catalyst via a transetherification process at 145–150 °C to yield a soluble, moderately high molecular weight hyperbranched polyether. The degree of branching in the polymer was calculated to be 0.78 by a comparison of its NMR spectrum with that of an appropriately designed model compound. The weight‐average molecular weight of the hyperbranched polymer was determined to be 64,600 (weight‐average molecular weight/number‐average molecular weight = 5.2) by size exclusion chromatography (SEC) in CHCl3 with polystyrene standards. The origin of the broad molecular weight distribution, which could either be intrinsic to such hyperbranched structures or be due to structural heterogeneity, was further probed by the fractionation of the samples by SEC and by the subjection of each fraction to matrix‐assisted laser desorption/ionization time‐of‐flight mass spectral analysis. The mass spectral analysis suggested the presence of two primary types of species: one corresponding to the simple branched structure and the other to macrocyclics. Interestingly, from the relative intensities of the two peaks, it was apparent that cyclization became favorable at higher conversions in the melt transetherification process. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4463–4476, 2002 相似文献
106.
The existence of a domain wall-like contribution to the free energy above the first order phase transition point is demonstrated
for a system described by the ϕ6-field theory in (1+1) dimensions. 相似文献
107.
Organically templated metal sulfates are relatively new. Six amine‐templated transition‐metal sulfates with different types of chain structures, including a novel iron sulfate with a chain structure corresponding to one half of the kagome structure, were synthesized by hydro/solvothermal methods. Amongst the one‐dimensional metal sulfates, [C10N2H10][Zn(SO4)Cl2] ( 1 ) is the simplest, being formed by corner‐linked ZnO2Cl2 and SO4 tetrahedra. [C6N2H18][Mn(SO4)2(H2O)2] ( 2 ) and [C2N2H10][Ni(SO4)2(H2O)2] ( 3 ) have ladder structures comprising four‐membered rings formed by SO4 tetrahedra and metal–oxygen octahedra, just as in the mineral kröhnkite. [C4N2H12][VIII(OH)(SO4)2]?H2O ( 4 ) and [C4N2H12][VF3(SO4)] ( 5 ) exhibit chain topologies of the minerals tancoite and butlerite, respectively. The structure of [C4N2H12][H3O][FeIIIFeII F6(SO4)] ( 6 ) is noteworthy in that it corresponds to half of the hexagonal kagome structure. It exhibits ferrimagnetic properties at low temperatures and the absence of frustration, unlike the mixed‐valent iron sulfate with the full kagome structure. 相似文献
108.
Sanjay Sarkar Nitika Tiwari Meerambika Behera Sankha Chakrabortty Kavya Jhingran Kali Sanjay Shirsendu Banerjee Suraj K. Tripathy 《印度化学会志》2022,99(5):100447
Dyes are commonly used in coloring clothes; in fertilizers, as anti-freezers, as detergents and so on. The use of such dyes has carcinogenic and genotoxic effects. These dyes require proper removal from the environment. Subsequently, a green and low-cost approach promises to adhere to sustainability of the environment while maximum removal of these toxic dyes. The present study describes removal of methyl violet (MV) dye by adsorption process magnetically separable Fe3O4-coir pith composites. The study was evaluated in batch system taking the optimum conditions as: pH: 7, contact time: 12 h, stirring speed: 200 rpm, concentration of dye: 100 mg/L, adsorbent weight: 3 g/L, temp.: 308 K. The central composite design approach of response surface methodology in design-expert software showed maximum removal efficiency (>98%) for optimal parameters. The experimental equilibrium data fitted reasonably well to Langmuir isotherm model. ANOVA analysis along with Fisher's statistical test was also performed to validate the model. The predicted model was at par with the experimental values with adjusted R2 of 0.9914. A thorough investigation of kinetic ( = 0.99; , thermodynamic, adsorption isotherm and eco-toxicological characteristics were performed for proper evaluations of the properties as well as sustainability of the adsorbent material. The whole research indicated encouraging potential of the developed material for adsorption, reusability and sustainability in applications for industrial scale wastewater treatment. 相似文献
109.
A. M. Stefanini M. Trotta B. R. Behera L. Corradi E. Fioretto A. Gadea A. Latina S. Szilner Y. W. Wu S. Beghini G. Montagnoli F. Scarlassara A. Yu. Chizhov I. M. Itkis N. A. Kondratiev I. V. Pokrovskiy R. N. Sagaidak G. N. Kniajeva E. M. Kozulin V. M. Voskressensky S. Courtin F. Haas N. Rowley 《The European Physical Journal A - Hadrons and Nuclei》2005,23(3):473-480
Measurements of fusion-evaporation cross-sections for the system 48Ca + 154Sm have been performed in the sub- and near-barrier energy range. Barrier-passing cross-sections have been obtained by adding recently measured capture-fission cross-sections at the same energies, and the barrier distribution for capture has been extracted. The data have been analyzed within a coupled-channel model, and a large subbarrier cross-section enhancement is observed, due to the ground-state prolate deformation of 154Sm. The 48Ca + 154Sm capture cross-sections are compared to existing data on 16O + 186W fusion, leading to the same CN, where a few higher-energy points have also been measured. The evaporation residue cross-sections for the two systems above the barrier indicate that complete fusion is inhibited for 48Ca + 154Sm by 40% in that energy region, with respect to 16O + 186W. 相似文献
110.
Noohi Nasim Jay Krishna Behera I. Sriram Sandeep V. V. RamaRao Basudeba Kar Antaryami Mishra 《Natural product research》2018,32(20):2494-2497
Pandanus odorifer (Forssk.) Kuntze is an economically important aromatic plant. The essential oil from male flowers is widely used in aromatherapy, cosmetics and as food flavouring agent. Phenylethyl methyl ether (PEME), the major constituent of essential oil, gives the chief characteristic fragrance to the oil. In the present study, 180 samples from 12 different regions were collected and hydrodistilled for essential oil isolation. The oil was then subjected to GC and GC-MS analysis to find out the percentage of the constituents. The results revealed PEME as the major constituent ranging from 58.03 to 81.86% and terpinen-4-ol, the second major constituent ranging from 7.81 to 21.46%. Soil nitrogen was found to be the most influential factor for oil yield and PEME content. The flowers containing high essential oil yield and PEME content could be used as elite chemotypes with enough potential for large-scale commercial cultivation to meet the demand of kewda industries. 相似文献