The effect of substituents and polymer media on photochromism kinetics of indolinospironaphthoxazine

The effect of substituents in indoline moiety and polymer media on photochromism and thermal decay processes of spirooxazine (ASP) was investigated. The thermal decoloration rate was decreased with increasing steric hindrance of substituents in l-position of indoline moiety. The stability of the colored forms was improved when the hydrogen in the 5-position of indoline moiety was replaced with electron-donating groups and was decreased when substituted by electron-withdrawing groups. In addition, the stability of the colored forms was related to properties of polymer media. The thermal decay rate decreased with an increase in the polarity and rigidity of polymer media. The themal decay kinetics of the colored forms obeyed biexponential decay law.     

Subphase pH effect on composition and structure of Fe(III) arachidate monolayers

The arachidic acid monolayers on Fe(III) subphase surfaces with various pH values have been studied. The π–A isotherms of monolayers and Fourier transform infra-red (FTIR) spectra of Langmuir–Blodgett (LB) films show that the films obtained on different pH subphases with a concentration of Fe(III) 5×10⁻⁵ M have different compositions. At low pH (2.4), the film appears to be almost 100% acid. The content of Fe(III) arachidate increases with increasing pH, at pH 3.7, the film appears to be 100% salt; and the content of salt decreases with pH larger than 3.7. The transmission electron microscope (TEM) observations show that the monolayer structures changed from patch aggregates formed by Fe(III) arachidate at low pH to a network or dotted structures formed by hydrolysates of Fe(III) at high pH. The Brewster angle microscopy (BAM) experiments show the different monolayer behaviors at various pH. These results indicate that the subphase pH greatly influenced the arachidic acid monolayers.     

MCDOCK: A Monte Carlo simulation approach to the molecular docking problem

Prediction of the binding mode of a ligand (a drug molecule) to its macromolecular receptor, or molecular docking, is an important problem in rational drug design. We have developed a new docking method in which a non-conventional Monte Carlo (MC) simulation technique is employed. A computer program, MCDOCK, was developed to carry out the molecular docking operation automatically. The current version of the MCDOCK program (version 1.0) allows for the full flexibility of ligands in the docking calculations. The scoring function used in MCDOCK is the sum of the interaction energy between the ligand and its receptor, and the conformational energy of the ligand. To validate the MCDOCK method, 19 small ligands, the binding modes of which had been determined experimentally using X-ray diffraction, were docked into their receptor binding sites. To produce statistically significant results, 20 MCDOCK runs were performed for each protein–ligand complex. It was found that a significant percentage of these MCDOCK runs converge to the experimentally observed binding mode. The root-mean-square (rms) of all non-hydrogen atoms of the ligand between the predicted and experimental binding modes ranges from 0.25 to 1.84 Å for these 19 cases. The computational time for each run on an SGI Indigo2/R10000 varies from less than 1 min to 15 min, depending upon the size and the flexibility of the ligands. Thus MCDOCK may be used to predict the precise binding mode of ligands in lead optimization and to discover novel lead compounds through structure-based database searching.     

In-situ Study of Charge and Discharge of Ni-MH Battery Using the Combined Method of Electrochemistry and Microcalorimetry

An apparatus to study the battery system has been set up. The thermal effects of charge and discharge of Ni-MH batteries have been studied. The calorimetric measurements indicate that the net heat dissipation during charging is larger than that during discharging. It is observed that the ratio of heat dissipation to charging energy varies with charging capacity, and almost 90 percent of charging energy is lost as heat dissipation near the end of the charging process at 97.7 mA. A jump of thermal curve near the end of discharge due to a secondary electrode reaction has been observed.This revised version was published online in November 2005 with corrections to the Cover Date.     

Electrophoretic characterization of a novel cysteine protease produced by Vibrio harveyi

Electrophoretic characterization of a novel cysteine protease produced by pathogenic luminous Vibrio harveyi, originally isolated from diseased tiger prawn Penaeus monodon in Taiwan, is demonstrated in the present study using native polyacrylamide gel electrophoresis (native PAGE), sodium dodecyl sulfate-PAGE (SDS-PAGE), crossed immunoelectrophoresis (CIE) and isoelectric focusing (IEF) gels. The protease has a pI of 6.4 and exhibits a fast-migrating feature in native-PAGE and CIE gels indicating that it is a negatively charged protease. The protease electrophoresed as a 22 kDa protein band in native- and SDS-PAGE (in SDS - buffer with or without the presence of 2-mercaptoethanol) while it electrophoresed as a 38 kDa protein band in SDS-PAGE when the samples were boiled for 10 min prior to electrophoresis. The results reveal that the enzyme is an SDS-resistant monomeric protease and its high negative charge is not influenced by SDS (detergent) without boiling the sample. The present results are useful in determining proteins of similar nature to this unique cysteine protease.     

GDX树脂富集－反相高效液相色谱法分离测定酚类化合物

用ＧＤＸ－５０２树脂富集的酚类化合物，经反相高效液相色谱法分离和检测，具有较好的准确度和精密度。     

同时测定食用植物油中抗氧剂叔丁基对羟基茴香醚和2，6－二叔丁基对甲酚的方法

报道了用高效液用色谱法同时测定食用植物油中的抗氧剂叔丁基对羟基茴香醚（ＢＨＡ）和２，６－二叔丁基对甲酚（ＢＨＴ）的实验方法。采用ＺｏｒｂａｘＯＤＳＣ_（１８）色谱住，甲醇：水（９０：１０，Ｖ／Ｖ）作流动相，检测波长为２４５ｎｍ，流速为１ｍＬ／ｍｉｎ。检测下限分别为１５ｎｇ（ＢＨＡ），９０ｎｇ（ＢＨＴ），回收率分别是９６．８％±９．８％（ＢＨＡ），９９．０％±３．２％（ＢＨＴ）。方法快速、准确，灵敏度高。     

利用纳米粒子组装的方法制备SERS活性基底

1974年，FIeishm。nn等人［‘］发现吸附在电化学粗糙化的银电极表面上的毗院分子，其Raman散射强度具有超乎寻常的增强现象．后来经过VanDuyne门和CreZghton问等人的研究，认识到这一现象属于～种特殊的表面效应，其增强因子高达卫矿，故被称为表面增强喇曼散射（Surfac－EI。     

磷化氢与烯烃反应的原位NMR谱研究

本文应用加压原位(in-situ)核磁共振技术,在反应温度70～75℃,压力1.0～2.0MPa,氘代苯为溶剂,偶氮二异丁腈(AIBN)为引发剂的条件下探索了磷化氢与丙烯腈,4-乙烯基吡啶,烯丙基胺,丙烯酰胺,氨基吡啉和N-乙烯基咔唑的自由基加成反应,结果表明除氨基吡啉之外的其它五种含氮化合物均能与磷化氢发生反应,从而找到合成含氮有机膦的良好路线。     

线粒体热化学研究──Ⅳ．鱼类肝脏线粒体代谢的微量热学研究

线粒体热化学研究──Ⅳ．鱼类肝脏线粒体代谢的微量热学研究谭安民，刘义，谢昌礼，屈松生，顾贫，邓凤姣（武汉大学化学系武汉４３００７２）（武汉大学生命科学院武汉）关键词鱼肝脏，线粒体，微量热学，热化学线粒体在能量代谢的过程中，除一部分能量用于合成ＡＴＰ外...