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51.
Limin Yang Danqun Huo Kun He Suyi Zhang Changjun Hou 《Applied biochemistry and biotechnology》2013,170(4):909-924
Plant esterase extracted from wheat flour play key roles in the spectrophotometric detection of organophosphorus compounds (OPs) for food safety and human health. The purpose of the present study was to investigate the role of tryptophan residues in the activity and structure of plant esterase by chemical modification and fluorometric studies. Active site characterization of purified plant esterase showed the involvement of tryptophan in the catalytic activity. Only one was essential for the enzyme activity by the Tsou’s analysis. Substrate protection experiments further confirmed that the tryptophan residue was located at the substrate-binding site. Fluorescence quenching studies elucidated that the tryptophan residues were largely exposed to the solvent, and a smaller fraction of the surface tryptophan residues had electropositively charged amino acids around them. Experimental results obtained here are expected to promote the applications of plant esterase in OPs detection. Further confirmation of the existence of other critical residues and detailed explanation of their functions were also required for the elucidation of the mechanism involved in the detection of OPs. 相似文献
52.
Lihua Zuo Heng Meng Jingjing Wu Zhen Jiang Shuying Xu Xingjie Guo 《Journal of separation science》2013,36(3):517-523
In this study, the enantioseparation of zopiclone, repaglinide, chlorphenamine maleate, brompheniramine maleate, dioxopromethazine hydrochloride, promethazine hydrochloride, liarozole, carvedilol, homatropine hydrobromide, homatropine methylbromide, venlafaxine, and sibutramine hydrochloride has been investigated using β‐CD in combination with a chiral ionic liquid (IL), 1‐ethyl‐3‐methylimidazolium‐L‐lactate. The influence of the type of IL and its concentration, BGE pH, and chain length of the IL cations on the resolution are discussed. Finally, the proposed method was successfully applied for the chiral impurity determination of eszopiclone in pharmaceutical tablets after validation with respect to accuracy and precision, linearity range, selectivity, repeatability, LOD and LOQ. It is assessed that the chiral impurity determination in the commercial tables is fewer than 0.1%. 相似文献
53.
The canonical brain storm optimization (BSO) employs clustering, creating and selecting operators, which are all connected and have great impacts on the optimization performance. In this paper, the state-of-the-art search strategies are introduced and the potential strengths and weaknesses of these strategies in the BSO algorithm are analyzed and compared from the perspective of the analytical model rather than any metaphors. The numerical experiments are carried out to artificially amplify and highlight the performance of various strategies. Finally, the progressive directions of the BSO algorithm are discussed for further research. 相似文献
54.
Shengli Niu Mengqi Liu Chunmei Lu Hui Li Mengjia Huo 《Journal of Thermal Analysis and Calorimetry》2014,115(1):73-79
Potential of carbide slag as transesterification catalyst is validated. Combined with X-ray fluorescence for ingredient determination, X-ray diffraction for textural phase analysis, scanning electron microscope for surface morphology observation and Hammett indicator for basic strength mensuration, thermal event of carbide slag is investigated through thermogravimetric analysis to estimate the potential of this calcium-based industrial waste as transesterification catalyst. Further, kinetic parameters are calculated through model-free method, where the experiments are conducted at temperature heating rates of 5, 10, 15, and 20 K min?1. As for activation energy and reaction order, Vyazovkin method and Avrami theory are respectively mentioned. Meanwhile, catalytic performance of carbide slag is labeled by transesterification efficiency and calcium hydroxide is conditionally mentioned for comparison. In conclusion, potential of carbide slag as transesterification catalyst is adequately validated. 相似文献
55.
56.
Dr. Yong Guo Dr. Wengang Li Dr. Jingjing Yan Dr. Basem Moosa Dr. Ma'an Amad Prof. Charles J. Werth Prof. Niveen M. Khashab 《化学:亚洲杂志》2012,7(12):2842-2847
Metal‐free fullerene (C60) was found to be an effective catalyst for the reduction of azo groups in basic aqueous solution under UV irradiation in the presence of NaBH4. Use of NaBH4 by itself is not sufficient to reduce the azo dyes without the assistance of a metal catalyst such as Pd and Ag. Experimental and theoretical results suggest that C60 catalyzes this reaction by using its vacant orbital to accept the electron in the bonding orbital of azo dyes, which leads to the activation of the N?N bond. UV irradiation increases the ability of C60 to interact with electron‐donor moieties in azo dyes. 相似文献
57.
58.
Two-Photon-Induced CO-Releasing Molecules as Molecular Logic Systems in Solution,Polymers, and Cells
Dr. Vadde Ramu Dr. Gandra Upendar Reddy Dr. Jingjing Liu Patrick Hoffmann Dr. Rudrakant Sollapur Dr. Ralf Wyrwa Dr. Stephan Kupfer Prof. Dr. Christian Spielmann Dr. Sylvestre Bonnet Prof. Dr. Ute Neugebauer Dr. Alexander Schiller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(36):8453-8458
Phototherapeutic applications of carbon monoxide (CO)-releasing molecules are limited because they require harmful UV and blue light for activation. We describe two-photon excitation with NIR light (800 nm)-induced CO-release from two MnI tricarbonyl complexes bearing 1,8-naphthalimide units ( 1 , 2 ). Complex 2 behaves as a logic OR gate in solution, nonwovens, and in HeLa cells. CO release, indicated by fluorescence enhancement, was detected in solution, nonwoven, and HeLa cells by single- (405 nm) and two-photon (800 nm) excitation. The photophysical properties of 1 and 2 have been measured and supported by DFT and TDDFT quantum chemical calculations. Both photoCORMs are stable in the dark in solution and noncytotoxic, leading to promising applications as phototherapeutics with NIR light. 相似文献
59.
Zhang YouMing Shi BingBing Zhang Peng Huo JianQiang Chen Pei Lin Qi Liu Jun Wei TaiBao 《中国科学:化学(英文版)》2013,56(5):612-618
Science China Chemistry - A non-sulfur chemosensor based on an easy to prepare double naphthalene Schiff base is reported for the colorimetric and fluorometric dual-channel sensing of Hg2+ ions by... 相似文献
60.
Liu Changqi Huo Dongying Yang Xu Ma Zhanwen Zhou Jianjin Han Chao Bai Xiaohou Wu Kang Zhang Yu Wang Junrun Yao Zeen Wei Zheng 《Journal of Radioanalytical and Nuclear Chemistry》2021,330(3):1091-1099
Journal of Radioanalytical and Nuclear Chemistry - A Frisch-grid Ionization Chamber (FGIC) for the measurement of low activity of alpha-particle emitters has been built. The design and performance... 相似文献