流动注射-分光光度法测定天然产物对酪氨酸酶活性的影响

建立了一种快速、灵敏且高精度的流动注射-分光光度法用于研究天然产物对酪氨酸酶活性的影响。此方法基于一定介质条件下L-3,4-二羟基苯丙氨酸(L-DOPA)在酪氨酸酶的作用下,发生氧化生成棕褐色多巴醌,其最大吸收峰位于475 nm处,而酪氨酸酶抑制剂能降低酶促反应速度,减少多巴醌形成的量,从而降低475 nm下的吸光度值,形成倒峰。在优化实验条件下,半抑制浓度的曲酸抑制酪氨酸酶活性测定相对标准偏差(n=10)为0.036%,与分光光度法和酶标仪微量法相比,精密度提高了10倍以上。咖啡酸对酪氨酸酶有较强的激活作用,对二酚酶相对激活率达到50%时的浓度(IC50)为0.170 mmol/L;薰衣草花水相提取物具有较强的抑制活性,其IC50值为0.96 mg/m L。与分光光度法及酶标仪微量法相比,流动注射-分光光度法精密度高,重复性好,适用于天然产物对酪氨酸酶活性影响的测定。     

A Porous Tricyclooxacalixarene Cage Based on Tetraphenylethylene

A quadrangular prismatic tricyclooxacalixarene cage 1 based on tetraphenylethylene (TPE) was efficiently synthesized by a one‐pot S_NAr condensation reaction. As a result of the porous internal structure in the solid state, cage 1 exhibited a good CO₂ uptake capacity of 12.5 wt % and a high selectivity for CO₂ over N₂ adsorption of 80 (273 K, 1 bar) with a BET surface area of 432 m² g^?1. Formation of cage 1 led to the fluorescence of TPE being switched on in solution. The system was employed as a single‐molecule platform to study the mechanism of aggregation‐induced emission (AIE) by examining the restriction of intramolecular rotation (RIR).     

果胶锆凝胶球对苯甲酸的吸附性能研究

用锆氧基离子与果胶反应制得果胶锆凝胶球,采用扫描电镜和红外光谱初步表征了凝胶球的结构,并测定了凝胶球的机械强度。研究了该凝胶球对苯甲酸的吸附性能。分别考察了果胶浓度、锆氧基离子浓度、吸附时间、p H值、温度及苯甲酸浓度对吸附性能的影响。结果表明,在298K下,果胶锆凝胶球对苯甲酸的吸附在4.5h左右达到平衡,当果胶的质量分数为3.0%,锆氧基离子质量分数为1.0%,苯甲酸初始浓度为500mg/L,吸附量可达73.89mg/g。所研究的吸附体系既适用于Freundlich方程,又适用于Langmuir方程;吸附过程为自发的放热、熵减过程,降低温度对吸附更有利。     

A Novel Preprocessing Algorithm for Three-Way HPLC Data

Orthogonal signal correction (OSC) was a data preprocessing algorithm. It ensured that the filtered information was irrelevant to concentration data while using it to filter the noise from the original data. This paper extended the OSC application range from two-way data to three-way data. Two drug data sets, Enoxacin, Norfloxacin, Ciprofloxacin and Betamethasone, cortisone acetate, prednisone acetate, showed that the application of the OSC algorithm to three-way HPLC data was feasible and needed further research.     

Selective oxidation of octadecan-1-ol to octadecanoic acid over Co3O4/SiO2 catalysts

Factors (reaction temperature, reaction time, flow rate of oxygen, amount of catalyst, etc.) influencing the catalytic properties of Co₃O₄/SiO₂catalyst in the oxidation octadecan-1-ol to octadecanoic acid were investigated. The catalysts were characterized by means of XRD, FT-IR and N₂-adsorption. The experimental results indicate that under the optimal condition the selectivity to octadecanoic acid reached 97.5 % over 5 % Co₃O₄/SiO₂ catalyst.This revised version was published online in December 2005 with corrections to the Cover Date.     

The effect of micro-morphology of Bi2O3 on catalytic properties of Co/Bi catalyst for wet air oxidation of acetic acid

The novel phase transfer catalysts S-8 [4-(dimethyloctylammonium) propansultan] and DB-X [1,4-bis(triethylmethylammonium)benzene dibromide] were synthesized and employed for high conversion synthesis of dichlorocyclopropane from various olefins.This revised version was published online in December 2005 with corrections to the Cover Date.     

A controlled porosity osmotic pump system with biphasic release of theophylline

A controlled porosity osmotic pump system with biphasic release of theophylline was developed for the nocturnal therapy of asthma. The developed system was composed of a tablet-in-tablet (TNT) core and a controlled porosity coating membrane. Release pattern of the developed system was influenced by amount of pore former (18.2-45.5%, w/w of polymer), weight gain (16-26 mg per tablet) of the coating membrane and osmotic agents used in inner layer of the TNT core. When sodium phosphate and sodium chloride were selected as the osmotic agents in inner and outer layer of the TNT core respectively, target release profile was obtained with coating solution cellulose acetate-polyethylene glycol 400-diethyl phthalate (54.5-36.4-9.1%, w/w) at a weight gain of 16-22 mg per tablet. To examine the mechanism of drug release, release profiles of osmotic agents, micro-environmental osmotic pressure and micro-environmental pH of the formulation during dissolution were studied. Micro-environmental osmotic pressure decreased and micro-environmental pH increased continuously during the whole dissolution process, theophylline release was dominated by the successive dissolution of sodium chloride and sodium phosphate. Theophylline solubility increased as environmental pH exceeded 10.8. At the last stage of the biphasic release, micro-environmental pH in the developed formulation reached 10.9, and theophylline release was promoted by its elevated solubility despite of the decrease of micro-environmental osmotic pressure in the developed formulaiton.     

氨基酸水杨醛席夫碱与铜(Ⅱ)配合物的合成及其抗菌活性和稳定性、结构间的关系

氨基酸水杨醛席夫碱与铜（Ⅱ）配合物的合成及其抗菌活性和稳定性、结构间的关系毕思玮＊刘树祥（曲阜师范大学化学系，曲阜２７３１６５）关键词：氨基酸水杨醛席夫碱铜（Ⅱ）稳定常数抗菌活性实验部分将１０ｍｍｏｌ氨基酸和０．５６ｇ（１０ｍｍｏｌ）ＫＯＨ溶于热的９...     

单斜ZnP2负极材料的锂化机理及性能

过渡金属磷化物电位低且比容量高, 是有发展前景的锂离子电池(LIBs)负极材料. 其中, ZnP₂属于双活性负极材料, Zn与P都能与Li⁺发生反应, 储Li⁺性能更具有竞争力. 但是, 对于ZnP₂的锂化机理及产物尚不明确. 采用第一性原理计算和电化学测试方法研究了ZnP₂的电子性质和电化学性能, 通过理论计算和实验测试相结合阐述了ZnP₂的锂化机制. 首先, 以密度泛函理论(DFT)计算揭示了ZnP₂的锂化机理、Li⁺扩散路径、势垒和理论比容量(1477 mAh/g). 其次, 通过直流电弧等离子体法及固相烧结法合成ZnP₂, 并测试其首圈放电曲线, 显示放电容量为1439 mAh/g, 与理论计算结果相近. 此外, 薄膜X射线衍射(XRD)检测最终产物成分为LiZn和Li₃P, 与DFT计算结果一致.     

铀(Ⅵ)的二溴水杨醛缩二胺类双希夫碱及溶剂三元配合物的合成和表征

Nine new complexes [UO₂(Dbsal-o-Phdn)L][UO₂(Dbsalen)L] and [UO₂(Dbsalpn)L] [Dbsal-o-PhdnH 2=N,N′-o-phenylenebis-(3,5-dibromosalicylideneimine), DbsalenH₂=N,N′-ethylenebis (3,5-dibromosalicylideneimine), DbsalpnH₂=N,N′-1,2-propanylenebis (3,5-dibromosalicylideneimine), L=MeOH, EtOH, py] have been synthesized and characterized by elemental analysis, IR, UV, TG-DTA and molar conductance analysis. These complexes are proposed to have seven coordinate environment.