Sol-gel derived iridium composite glucose biosensor

Iridium powder is introduced into sol-gel process for the first time to fabricate a novel type of sol-gel derived metal composite electrode. The iridium ceramic electrode shows excellent electrocatalytic action for both oxidation and reduction of hydrogen peroxide. The glucose biosensor based on sol-gel derived iridium composite electrode was fabricated. The biosensor shows highly selectivity towards glucose because of the strong catalytic action of iridium composite matrix for enzyme-liberated hydrogen peroxide at low operating potential, at which common interferences cannot be sensed. The novel type of biosensor can be renewed by simply mechanical polishing with favorable reproducibility and long-term stability.

Sol-gel derived iridium composite glucose biosensor

Iridium powder is introduced into sol-gel process for the first time to fabricate a novel type of sol-gel derived metal composite electrode. The iridium ceramic electrode shows excellent electrocatalytic action for both oxidation and reduction of hydrogen peroxide. The glucose biosensor based on sol-gel derived iridium composite electrode was fabricated. The biosensor shows highly selectivity towards glucose because of the strong catalytic action of iridium composite matrix for enzyme-liberated hydrogen peroxide at low operating potential, at which common interferences cannot be sensed. The novel type of biosensor can be renewed by simply mechanical polishing with favorable reproducibility and long-term stability.

Electrochemiluminescent determination of glucose with a sol-gel derived ceramic-carbon composite electrode as a renewable optical fiber biosensor

A sol-gel derived ceramic-carbon composite electrode is used for fabrication of a new type of optical fiber biosensor based on luminol electrochemiluminescence (ECL). The electrode consists of graphite powder impregnated with glucose oxidase in a silicate network. In this configuration, the immobilized enzyme oxidizes glucose to liberate hydrogen peroxide and graphite powder provides percolation conductivity for triggering the ECL between luminol and the liberated hydrogen peroxide. Both of the reactions occur simultaneously on the surface of the composite electrode, thereby the response of the biosensor is very fast. The peak intensity was achieved within only 20 s after glucose injection. In addition, the electrode could be renewed by a simple mechanical polishing step in case of contamination or fouling. The linear range extends from 0.01 to 10 mM for glucose and the detection limit is about 8.16 muM. The renewal repeatability and stability of the biosensor are also investigated in detail.

具有多重玻璃化转变的梳状聚合物的合成、表征和导电性—侧链分子量为550的聚乙二醇单甲醚

以分子量为 5 5 0的聚乙二醇单甲醚为侧链 ,苯乙烯 /马来酸酐共聚物为骨架 ,合成了苯乙烯 /马来酸酐共聚物多缩乙二醇酯。用红外光谱、元素分析、DSC、热失重等方法 ,对合成条件、产物结构和性能进行了研究。结果表明 :反应严格按照反应方程进行 ,精制产物是非晶的梳状聚合物。玻璃化转变温度为 30 .6 8℃ ,分解温度为 1 2 0℃。对动态力学性能及其锂盐复合物离子导电性进行了研究 ,表明α转变温度和β转变温度分别是 2 8℃和 -4 7.7℃。随着盐浓度的增加 ,盐浓度与电导率的关系呈现出双峰或多峰。电导率与温度的依赖关系符合VTF方程。室温电导率最高可达 4.2× 1 0 -5 S·cm-1。

Preparation and properties of a selenium-containing catalytic antibody as type I deiodinase mimic

Conversion of thyroxine (T-4) to 3,5,3'-triiodothyronine is an essential first step in controlling thyroid hormone action. Type I deiodinase (DI) can catalyze the conversion to produce the bulk of serum 3,5,3'-triiodothyronine. Acting as a mimic of DI, a selenium-containing catalytic antibody (Se-4C5) prepared by converting the serine residues of monoclonal antibody 4C5 raised against T4 into selenocysteines, can catalyze the deiodination of T4 with dithiothreitol (DTT) as cosubstrate. The mimic enzyme Se-4C5 exhibited a much greater deiodinase activity than model compound ebselen and another selenium-containing antibody Se-Hp4 against GSH. The coupling of selenocysteine with the combining pocket of antibody 4C5 endowed Se-4C5 with enzymatic activity. To probe the catalytic mechanism of the catalytic antibody, detailed kinetic studies were carried out in this paper. Investigations into the deiodinative reaction revealed the relationship between the initial velocity and substrate concentration. The characteristic parallel Dalziel plots demonstrated that Se-4C5-catalyzed reaction mechanism was ping-pong one, involving at least one covalent enzyme intermediate. The kinetic properties of the catalytic antibody were similar to those of DI, with K-m values for T-4 and DTT of approximately 0.8 muM and 1.8 muM, respectively, and a V-m value of 270 pmol per mg of protein per min. The activity could be sensitively inhibited by 6-propyl-2-thiouracil (PTU) with a K-i value of similar to 120 muM at 2.0 muM T-4 concentration. The PTU inhibition was progressively alleviated with the increasing concentration of added DTT, revealing that PTU was a competitive inhibitor for DTT.

A selenium-containing catalytic antibody with type I deiodinase activity

Acting as a mimic of type I deiodinase (DI), a selenium-containing catalytic antibody (Se-4C5) prepared by converting the serine residues of monoclonal antibody 4C5 raised against thyroxine (T-4) into selenocysteines, can catalyze the deiodination of T-4 to 3,5,3'-triiodothyronine (T-3) with dithiothreitol (DTT) as cosubstrate. Investigations into the deiodinative reaction by Se-4C5 revealed the relationship between the initial velocity and substrate concentration was subjected to Michaelis-Menten equation and the reaction mechanism was ping-pong one. The kinetic properties of the catalytic antibody were a little similar to those of DI, with K-m values for T-4 and DTT of approximately 0.8 muM and 1.8 mM, respectively, and V-m value of 270 pmol per mg protein per min. The activity could be sensitively inhibited by PTU with a K-i value of approximately 120 muM at 2.0 muM of T-4 concentration, revealing that PTU was a competitive inhibitor for DTT, (C) 2001 Academic Press.

胆甾液晶／聚合物多组分体系的结构与性质的研究 Ⅱ．壬酸胆甾酯／聚（甲基丙烯酸甲酯－甲基丙烯酸丁酯）混合体系的结晶动力学研究

研究了壬酸胆甾酯与甲基丙烯酸甲酯－甲基丙烯酸丁酯无规共聚物共混体系的等温结晶动力学．讨论了共聚物组成及分子链刚性对体系中胆甾液晶组分结晶速度及成核方式的影响

吡啶－2，6－二甲酸镧钇异核配合物的合成及晶体结构

合成了吡啶－２，６－二甲酸镧钇异核配合物晶体。元素分析结果表明，化学式为ＬａＹ（ＨＤＰＡ）＿２·（ＤＰＡ）＿２．１２Ｈ＿２Ｏ，ＤＰＡ为吡啶－２，６－二甲酸根。用Ｘ射线衍射法测定了配合物的单晶结构，其结构式为［ＬａＹ（ＨＤＰＡ）＿２（ＤＰＡ）＿２（Ｈ＿２Ｏ）＿４」·８Ｈ＿２Ｏ，属单斜晶系，Ｐ２＿１／ａ空间群。晶胞参数：ａ＝１．２９７５（４）ｎｍ，ｂ＝１．１２６６（３）ｎｍ，ｃ＝１．４０７９（３）ｎｍ；β＝１０２；１５（２）°，Ｖ＝２．０１１９０（１）ｎｍ￣３，Ｚ＝４，Ｄｃ＝１．８３ｇ／ｃｍ￣３，稀土离子的配位数为９，其配位多面体为扭曲的三冠三角棱柱体。

稀土萃取信息系统

应稀土化学发展的需要,我们组建了稀土萃取信息系统。其中包括:数据的来源和数据类型;数据的组织;检索功能;数据间的关联;最优化设计以及萃取剂结构与其物理性质和结构与萃取性能的相关分析研究。

C-13 AND H-1 NMR STUDIES OF SOLUTION STRUCTURE OF LANTHANIDE COMPLEX WITH GLYCYL-GLYCINE

C-13 and H-1 NMR technique was used to study the interaction of Gly-Gly with heavy lanthanide cations Dy3+, Ho3+, Er3+, Tm3+ and Yb3+ in aqueous solution. The stability constants for the 1:1 and 1:2 complexes of Gly-Gly with Ho3+ and Yb3+ were determined from the titration curves of chemical shift versus concentration ratio of lanthanide to Gly-Gly. The solution structure of the Ln-Gly-Gly complex was analyzed based upon the C-13 and H-1 lanthanide induced shifts and the results show that in the complex Gly Gly is coordinated to the lanthanide ion through the carboxyl oxygens with the backbone of the ligand in an extended state.

双甘肽稀土配合物溶液结构的~(13)C~1H NMR研究

关于双甘肽的~(13)C化学位移行为及其与稀土离子的配位作用前人有过报导。但有关水溶液中双甘肽稀土配合物的结构仍不清楚。本文测定了在重稀土离子Dy~(3+)、Ho~(3+)、Er~(3+)、Tm~(3+)和Yb~(3+)作用下双甘肽~(13)C和~1H的顺磁诱导位移,研究了水溶液中双甘肽稀土配合物的组成及结构。1 实验部分

取代苯胺的化学氧化聚合

本文研究了甲苯胺(O-,m-,p-)在盐酸水溶中的聚合反应。结果表明,三种甲苯胺的聚合强烈依赖于氧化剂浓度和聚合介质的pH值。用IR、NMR和元素分析等手段表征了可溶聚合物。

Ulva diversity in the Yellow Sea during the large-scale green algal blooms in 2008-2009

P>In the Yellow Sea of China, large-scale green tides have broken out for three consecutive years from 2007 to 2009. As part of the efforts to localize the algal source, two cruises were conducted in the early stage and the outbreak stage of the bloom in 2009. We analyzed the morphological and genetic diversity of drifting Ulva specimens and culture-derived isolates from seawater sampled in different localities. For phylogenetic analyses, the nuclear encoded ribosomal DNA internal transcribed spacer region (ITS nrDNA) and the plastid encoded large subunit of ribulose-1, 5-bisphosphate carboxylase/oxgenase gene (rbcL) were used. Our molecular and morphological data indicate that the dominant free-floating Ulva species in 2008 and 2009 possibly belonged to a single strain of the U. linza-procera-prolifera (LPP) clade. The ITS sequences from bloom-forming algal samples with dense branches were identical to those from U. linza-like specimens without branches derived from the Yellow Sea. Microscopic individuals of the dominant Ulva strain were detected in eight stations, revealing that spore dispersal in the water helped to enlarge biomass in the water during the outbreak stage of green tide in the Yellow Sea.

Responses of vegetative gametophytes of Undaria pinnatifida to high irradiance in the process of gametogenesis

The population of Undaria pinnatifida in its ecologic niche sustains itself in high temperature summer in the form of vegetative gametophytes, the haploid stage in its heteromorphic life cycle. Gametogenesis initiates when seawater temperature drops below the threshold levels in autumn in the northern hemisphere. Given that the temperature may fall into the appropriate range for gametogenesis, the level of irradiance determines the final destiny of a gametophytic cell, either undergoing vegetative cell division or initiating gametogenesis. In elucidating how vegetatively propagated gametophytes cope with changes of irradiance in gametogenesis, we carried out a series of culture experiments and found that a direct exposure to irradiance as high as 270 mu mol photons m(-2) s(-1) was lethal to dim-light (7-10 mu mol photons m(-2) s(-1)) adapted male and female gametophytes. This lethal effect was linearly corelated with the exposure time. However, dim-light adapted vegetative gametophytes were shown to be able tolerate as high as 420 mu mol photons m(-2) s(-1) if the irradiance was steadily increased from dim light levels (7-10 mu mol photons m(-2) s(-1)) to 90, 180 and finally 420 mu mol photons m(-2) s(-1), respectively, at a minimum of 1-3 h intervals. Percentage of female gametophytic cells that turned into oogonia and were eventually fertilized was significantly higher if cultured at higher but not lethal irradiances. Findings of this investigation help to understand the dynamic changes of population size of sporophytic plants under different light climates at different site-specific ecologic niches. It may help to establish specific technical details of manipulation of light during mass production of seedlings by use of vegetatively propagated gametophytes.