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排序方式: 共有134条查询结果,搜索用时 31 毫秒
41.
In the present work, we report a novel nanocomposite gel electrolytes based on intercalation of hyperbranched polyurethane (HBPU) into organically modified montmorillonite for application in Li-ion batteries. The nanocomposites have been prepared by solution intercalation technique with varying clay loading. The formation of partially exfoliated nanocomposites has been confirmed by X-ray diffraction. Nanocomposites were soaked with 1 M LiCO4 in 1:1 (v/v) solution of propylene carbonate and diethyl carbonate to get the required gel electrolytes. AC impedance analysis shows that ionic conductivity increases with the increase of clay loading and attains the highest value of 8.3?×?10?3 S/cm for 5 wt.% clay concentration. Surface morphology of the nanocomposite electrolytes has been examined by SEM analysis. Improvement of electrochemical properties, viz., electrochemical potential window and interfacial stability, is also observed in the clay-loaded HBPU samples. 相似文献
42.
Motivated by recent applications of the Mann–Whitney U test to large data sets we took a critical look at current methods for computing its significance. Surprisingly, we found
that the two fastest and most popular tools for exact computation of the test significance, Dinneen and Blakesley’s and Harding’s,
can exhibit large numerical errors even in moderately large datasets. In addition, another method proposed by Pagano and Tritchler
also suffers from a similar numerical instability and can produce inaccurate results. This motivated our development of a
new algorithm, mw-sFFT, for the exact computation of the Mann–Whitney test with no ties. Among the class of exact algorithms
that are numerically stable, mw-sFFT has the best complexity: O(m
2
n) versus O(m
2
n
2) for others, where m and n are the two sample sizes. This asymptotic efficiency is also reflected in the practical runtime of the algorithm. In addition,
we also present a rigorous analysis of the propagation of numerical errors in mw-sFFT to derive an error guarantee for the
values computed by the algorithm. The reliability and efficiency of mw-sFFT make it a valuable tool in compuational applications
and we plan to provide open-source libraries for it in C++ and Matlab. 相似文献
43.
Ram Niranjan R.K. Rout B.S. Tomar P.S. Ramanjaneyulu D.B. Paranjape T.C. Kaushik 《Physics letters. A》2018,382(46):3365-3368
Pulsed neutrons generated in a plasma focus device are used for the thermal neutron activation analysis (TNAA) of selected three elements having widely different half-lives varying from a few seconds to a few days [Dysprosium (Dy), Manganese (Mn) and Gold (Au)]. Neutron pulse having strength of neutrons/pulse with a pulse width of is produced by “MEPF-12” device operated at a filling gas (deuterium + 0.5% krypton) pressure of 3 mbar. The fast 2.45 MeV D–D neutrons are thermalized before irradiating the sample. The decay gammas from the radioisotopes 165mDy (), 56Mn (), and 198Au () produced via reactions, 164Dy()165mDy, 55Mn() 56Mn, and 197Au() 198Au respectively are counted off-line in a lead shielded well type NaI(Tl) detector coupled to a calibrated 2048 channel analyzer. The values of half-lives evaluated from the measured decay gammas, , and respectively for the radioisotopes of Dy, Mn and Au, are seen to be close to the values reported in literature. 相似文献
44.
Kiramage Chathuranga Asela Weerawardhana Niranjan Dodantenna Jong-Soo Lee 《Experimental & molecular medicine》2021,53(11):1647
A harmonized balance between positive and negative regulation of pattern recognition receptor (PRR)-initiated immune responses is required to achieve the most favorable outcome for the host. This balance is crucial because it must not only ensure activation of the first line of defense against viral infection but also prevent inappropriate immune activation, which results in autoimmune diseases. Recent studies have shown how signal transduction pathways initiated by PRRs are positively and negatively regulated by diverse modulators to maintain host immune homeostasis. However, viruses have developed strategies to subvert the host antiviral response and establish infection. Viruses have evolved numerous genes encoding immunomodulatory proteins that antagonize the host immune system. This review focuses on the current state of knowledge regarding key host factors that regulate innate immune signaling molecules upon viral infection and discusses evidence showing how specific viral proteins counteract antiviral responses via immunomodulatory strategies.Subject terms: Innate immunity, Post-translational modifications 相似文献
45.
An aza-ene reaction has been used for the first time for the synthesis of two 5-membered lactam-hydrazides, each with a built-in allylsilane terminator for further elaboration. One of the lactam-hydrazides was transformed via an allylsilane-hydrazonium ion ring closure to a fused tetrahydropyrazole which may be considered as a mono-nitrogen analog of the biologically significant necine bases. A density functional theoretical study (B3LYP/6-21G*) was undertaken to provide insight into the factors that favor a synclinal transition structure of the hydrazonium ion intermediate leading to the tetrahydropyrazole. This stereocontrolled synthesis served as a model for the multi-step conversion of the other lactam-hydrazide, the substituted 2-pyrrolidinone, to necine bases (±)-supinidine and (±)-macronecine. An allylsilane-aldehyde ring closure formed the key step in the synthesis of these natural products. 相似文献
46.
AbstractShankhpushpi, traded in the Indian market is having different controversial botanical sources, that is, Convolvulus pluricaulis Choisy (Convulvulaceae), Clitoria ternatea Linn. (Papilionaceae), and Evolvulus alsinoides Linn. (Convulvulaceae). Simple, accurate and precise RP-HPLC-PDA method was established for quality assessment and discrimination of Shankhpushpi samples using chromatographic profiling method. In distinction to the routine method of quality assessment which uses single or dual marker peaks, all chromatographic data (retention times/variables) were used. Fifteen shankhpushpi samples were purchased from the market including authenticated samples of all three C. pluricaulis, C. ternatea, E. alsinoides. A total of 18 samples were analyzed by HPLC and the dataset was then treated with multivariate analyses like PCA and HCA by using MINITAB software. Thus, the developed method was useful in discriminating the Shankhpushpi samples and for the perseverance of quality control. 相似文献
47.
Summary Solid aquo CuII complexes of Schiff bases derived from amino acids have been prepared and characterized. Using a pH-stat method, the kinetics of base hydrolysis of the amino acid esters H2NCH2CO2Me·HCl (GE), (HO)-C6H4CH2(NH2)CO2Me·HCl (TE), MeS(CH2)2CH(NH2)-CO2Me·HCl (ME), HSCH2CH(NH2)CO2Et·HCl (CE), C3H3N2CH2CH(NH2)CO2Me·2HCl (HE) and [—SCH2-CH(NH2)CO2Me]2·2HCl (CysE) have been studied. The complexes enhanced the rate of hydrolysis substantially, the values of the second-order rate constants being some 10–50 times greater than those obtained in the presence of the simple CuII ion. 相似文献
48.
A selective, precise, and accurate high-performance thin-layer chromatographic (HPTLC) method has been proposed for the analysis of garlic and its formulations for their alliin content. The method involves densitometric evaluation of alliin after resolving it by HPTLC on silica gel plates with n-butanol-acetic acid-water (6 + 2 + 2, v/v) as the mobile phase. For densitometric evaluation, peak areas were recorded at 540 nm after derivatizing the resolved bands with ninhydrin reagent. The relation between the concentration of alliin and corresponding peak areas was found to be linear within the range of 250 to 1500 ng/spot. The method was validated for precision (interday and intraday), repeatability, and accuracy. Mean recovery was 98.36%. The method was applied for the quantitation of alliin in bulbs of Allium sativum Linn. (garlic) and its formulations. The proposed TLC method was found to be precise, specific, sensitive, and accurate and can be used for routine quality control of garlic and its formulations. 相似文献
49.
Elisa Biasin Daniel R. Nascimento Benjamin I. Poulter Baxter Abraham Kristjan Kunnus Angel T. Garcia-Esparza Stanislaw H. Nowak Thomas Kroll Robert W. Schoenlein Roberto Alonso-Mori Munira Khalil Niranjan Govind Dimosthenis Sokaras 《Chemical science》2021,12(10):3713
Ru-complexes are widely studied because of their use in biological applications and photoconversion technologies. We reveal novel insights into the chemical bonding of a series of Ru(ii)- and Ru(iii)-complexes by leveraging recent advances in high-energy-resolution tender X-ray spectroscopy and theoretical calculations. We perform Ru 2p4d resonant inelastic X-ray scattering (RIXS) to probe the valence excitations in dilute solvated Ru-complexes. Combining these experiments with a newly developed theoretical approach based on time-dependent density functional theory, we assign the spectral features and quantify the metal–ligand bonding interactions. The valence-to-core RIXS features uniquely identify the metal-centered and charge transfer states and allow extracting the ligand-field splitting for all the complexes. The combined experimental and theoretical approach described here is shown to reliably characterize the ground and excited valence states of Ru complexes, and serve as a basis for future investigations of ruthenium, or other 4d metals active sites, in biological and chemical applications.Combined experimental and theoretical Ru 2p4d resonant inelastic X-ray scattering study probes the chemical bonding and the valence excited states of solvated Ru complexes. 相似文献
50.