磷脂囊泡在胺端基和羧端基修饰金表面的沉积

磷脂囊泡与阴,阳离子性表面作用的深入理解对磷脂的生物纳米科技应用具有重要意义.通过石英电子微天平及耗散系数测量仪,研究了不同离子性磷脂囊泡在胺端基和羧端基修饰Au衬底的沉积行为.实验观察到四条囊泡沉积路径:(ⅰ)吸附至临界值后破裂成膜;(ⅱ)吸附即破裂成膜;(ⅲ)吸附不破裂;(ⅳ)不吸附.沉积路径由囊泡与衬底的双电层相互作用决定,离子可发挥调节作用.     

Production of multi-hollow polymer microspheres by stepwise alkali/acid method II. Alkali treatment process

Recently, we reported that multi-hollow polymer microspheres can be produced by a two-step treatment of submicron-size styrene-butyl acrylate-methacrylic acid (74.3/17.0/8.7, molar ratio) terpolymer emulsion particles with alkali and acid. In this article, the effects of initial pH value, temperature and time in the process of alkali treatment — the first step in the formation of the multi-hollow structure within the particles — are examined in detail.Part CXXVIII of the series of Studies on Suspension and Emulsion     

Production of multihollow polymer particles by the stepwise alkali/acid method IV. Acid treatment process

The effects of pH, temperature and time in the acid-treatment process on the multihollow structure formed within submicron-sized monodispersed polymer particles by the stepwise alkali/acid method proposed by the authors were examined in detail. The original particles were produced by emulsifier-free emulsion terpolymerization of styrene, butyl acrylate, and methacrylic acid. It was clarified that the number and the size of hollows per particle were drastically changed by the acid treatment conditions as well as those in the alkali treatment process.Part CXLV of the series Studies on Suspension and Emulsion     

The synthesis of potential Neramexane metabolites: cis- and trans-3-amino-1,3,5,5-tetramethylcyclohexanecarboxylic acids

A seven step synthetic route toward potential Neramexane metabolites cis- and trans-3-amino-1,3,5,5-tetramethylcyclohexanecarboxylic acids, cis-1 and trans-1, has been developed from isophorone. The synthetic procedure represents a useful method for the preparation of γ-amino acids with both amino and carboxyl groups situated at tertiary carbon atoms.     

Decontamination of vegetables sprayed with organophosphate pesticides by organophosphorus hydrolase and carboxylesterase (B1)

A genetically engineered Escherichia coli cell expressing both organophosphorus hydrolase (OPH) and carboxyl esterase (CaE) B1 intracellularly was constructed and cultivated. The harvested wet cells were vacuum dried, and the storage stability of the dried cell powder was determined in terms of OPH activity. Over a period of 5 mo, the dried cells showed no significant decrease in the activities of the detoxifying enzymes. The crude enzymes in 50 mM citrate-phosphate buffer (pH 8.0) were able to degrade approx 97% of the organophosphate pesticides sprayed on cabbage. The detoxification efficiency was superior to that of the treatments of water, detergent, and a commercially available enzyme product. Additionally, the products of pesticide hydrolysis generated by treatment with the enzyme extract were determined to be virtually nontoxic.     

乙炔法合成醋酸乙烯催化剂载体表面羧基与羰基作用机理的研究

比较了硝酸、硫酸、过氧乙酸改性对载体比表面积、孔结构、pH值以及载体表面基团的影响. 研究了过氧乙酸(PAA)改性条件对催化剂活性的影响. 改性提高了活性炭表面羧基和羰基的含量, 由在最佳PAA改性条件下制备的乙炔法合成醋酸乙烯催化剂生产能力比未经过氧乙酸改性活性炭制备的催化剂提高了14.58%. 得到了过氧乙酸改性后活性炭表面羧基和羰基总量(m)和合成醋酸乙烯催化剂生产能力(P)之间的关系为P＝1.83＋2.26×10－3×e3.17m, 并讨论了催化剂表面羧基与羰基提高催化剂活性的机理.     

新型四羧基铝酞菁-二氧化硅荧光纳米粒子的合成及在酸度测定中的应用

首次制备出红区荧光染料四羧基铝酞菁掺杂的二氧化硅纳米粒子,并对其进行了表征。将环己烷、正己醇和表面活性剂Triton X-100按一定体积比(12.3∶1.04∶1)混合均匀,形成清澈透明的溶液;将适量的四羧基铝酞菁溶解到浓氨水中,加入到上述混合溶液中,形成反向胶束。搅拌10 m in后加入一定量的四乙氧基硅烷,加快搅拌速度,促使四乙氧基硅烷进入反相胶束中的“纳米水池”,在碱性条件下,四乙氧基硅烷水解形成二氧化硅纳米粒子。采用该方法制备的核壳荧光纳米颗粒荧光稳定性强,生物相容性高,抗干扰能力强。将一定量四羧基铝酞菁掺杂的二氧化硅纳米粒子溶于水溶液中,随溶液pH值的增加,荧光强度增强,并在pH 5.02~11.98的范围内,荧光强度与溶液酸度有良好的线性关系。该法已成功地用于自来水和模拟生物体系中pH的测定。预期该技术有望用于细胞内H 的实时监测。     

功能高分子磁性微球的制备及分析应用

通过分散聚合法制备功能高分子磁性微球 ,并有效地控制微球的粒径范围和微球表面活性基团。以乙醇 水为分散体系 ,对磁流体Fe3O4 表面进行苯乙烯和丙烯酸共聚反应 ,制得粒径均匀、分散性好、带有羧基的磁性微球。该微球经活化后和抗癌药物阿霉素结合 ,在自制磁性电解池中 ,可用金膜电极进行电化学检测。阿霉素磁性微球在 - 0 .4 0V处有一个明显的还原峰 ,在浓度为 7.2 5× 10 - 1 0 ～ 7.2 5× 10 - 9mol L范围内峰电流和阿霉素浓度的关系呈线性 ,检测下限达 3.6× 10 - 1 0 mol L。     

蛋白酶在有机合成中应用的新进展

介绍了有机溶剂中酶促反应的一些基本概念, 总结了酶促反应的发展情况, 归纳了近几年来将蛋白酶应用于有机合成的一些新策略。