Ganoderic acid Sz, a new lanostanoid from the mushroom Ganoderma lucidum

A new lanostanoid, ganoderic acid SZ (1), isolated from a lipophilic extract of the fruiting body of Ganoderma lucidum, is a geometric Z-isomer of the known ganoderic acid S (2). The structure of ganoderic SZ (1) was deduced mainly by 1D and 2D NMR studies. During the course of this study, 12 known lanostanoids have also been isolated and characterized.     

甲基丙烯酸(3-三甲氧基硅)丙酯-马来酸二丁基锡共聚物/二氧化硅杂化材料的制备

甲基丙烯酸（３ 三甲氧基硅）丙酯 马来酸二丁基锡共聚物／二氧化硅杂化材料的制备周文董建华丘坤元（北京大学化学与分子工程学院高分子科学与工程系，１００８７１北京）ＷｅｉＹｅｎ（危岩）（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，Ｄｒｅｘｅｌ...     

氮的四原子簇合物的从头算研究

在4－31G基组水平上，对氮的四原子簇合物：N42+，N4和N24-做了从头算研究．几何优化和振动分析表明：N24+，N4能量最低的构型分别为直线的D∞h结构和平面的D2h结构，N24-则为D4h结构，并将氮与磷的四原子簇合物做了比较．     

藉铋-亚硝基R盐-结晶紫反应高灵敏分光光度测定痕量铋

本文提出了一个超高灵敏测定铋的分光光度方法。缔合物的吸收峰位于600um，表观摩尔吸光系数ε600＝3．0×109L·mol’·cm－1，铋浓度在0～200ng／L范围内遵守比耳定律。本法用于水样和合成试样中痕量铋的测定，结果较满意。对缔合物组成与显色机理进行了初步讨论。     

The mutual catalytic effect in kinetic reactions and its application to simultaneous determination of binary components

The mutual catalytic effect between iron(II) and antimony(III) on the chromium(VI)-iodide kinetic reactions has been studied by stopped-flow FIA. The concept of mutual catalytic coefficient is defined. The deviations from additive principles of absorbance within certain concentration ranges in previous procedures can be compensated effectively, by introducing the mutual catalytic coefficient into the simultaneous determination of a binary mixture with stopped-flow-FIA method. The linear concentration ranges have been enlarged, 0–3.5 g/ml Fe(II) and 0–3.7 g/ml Sb(III) compared with 0–1.2 g/ml Fe(II) and 0–2.0 g/ml Sb(III) without use of the coefficient. Iron and antimony contents in wastewater, a simulated sample and a zinc standard were determined, the recoveries and relative standard deviations being, respectively, 99.8–101.3% and 2.7–3.6% for iron and 95.4–100.3% and 2.3–5.3% for antimony compared with 95.2–98% and 3.0–4% for iron and 96–104% and 4.5–4.8% for antimony, assuming additivity.     

Ansa-茂锆催化剂对乙烯/1-辛烯共聚合研究

乙烯与α 烯烃共聚合可制得线性低密度聚乙烯等重要塑料产品．用茂金属催化剂与甲基铝氧烷（ＭＡＯ）助催化剂合成的乙烯／α 烯烃共聚物具有共单体分布均匀，分子量分布窄等特点，其性能比传统的Ｚｉｅｇｌｅｒ Ｎａｔａ催化剂体系所得共聚物优越．茂金属化合物的结构...     

协同系数补偿—动力学两次标准加入法测定相互干扰的双组份

本提出了协同铲应补偿的动力两次标准加入法，讨论了相互干扰双组份同时测定的原理，研究了钙（Ⅵ）和钨（Ⅵ）催化的Ｈ２Ｏ２－Ｉ＾－动力学反应，确定了同时测定条件：［Ｈ２Ｏ２］＝９．×１０＾－３ｍｏｌ／Ｌ，［Ｉ＾－］＝１．０×１０ｍｏｌ／Ｌ，ＰＨ３．０，２５℃；为补偿钼和钨之间的协同催化效化效应，引入了协同催化系数的概念，有效地消除了吸江度对加和性的偏离。用本法同时测定样品中的钼和钨含量，回收率分别为９     

Indoprofen upregulates the survival motor neuron protein through a cyclooxygenase-independent mechanism

Most patients with the pediatric neurodegenerative disease spinal muscular atrophy have a homozygous deletion of the survival motor neuron 1 (SMN1) gene, but retain one or more copies of the closely related SMN2 gene. The SMN2 gene encodes the same protein (SMN) but produces it at a low efficiency compared with the SMN1 gene. We performed a high-throughput screen of approximately 47,000 compounds to identify those that increase production of an SMN2-luciferase reporter protein, but not an SMN1-luciferase reporter protein. Indoprofen, a nonsteroidal anti-inflammatory drug (NSAID) and cyclooxygenase (COX) inhibitor, selectively increased SMN2-luciferase reporter protein and endogenous SMN protein and caused a 5-fold increase in the number of nuclear gems in fibroblasts from SMA patients. No other NSAIDs or COX inhibitors tested exhibited this activity.     

Determination of As,Cd, Hg,Cu and Zn in biological samples by radiochemical neutron activation analysis

In this work, a simple group separation scheme based on extraction for NAA determination of trace of As, Cd, Hg, Cu and Zn in biological materials is described. For this purpose, zinc-diethyldithiocarbamate, Zn(DDC)₂, and methyl isobutyl ketone-iodide have been chosen as reagents. The elements can be extracted successively and quantitatively from strong mineral acids without adjusting pH of the solution, and separated into two groups suitable for gamma-ray spectrometry. Samples of 100–200 mg dry weight were double-sealed into polyethylene bags and irradiated in a swimming pool reactor with a thermal neutron flux of 10¹³n·cm^–2·s^–1 for 44 hours. After a cooling period of 1–3 days, the samples were digested with microgram quantities of carrier in concentrated nitric acid and sulfuric acid at 150°C for 3.5 hours in a teflon bomb, then extracted as described above. The reliability of the analytical method was checked using reference materials Horse Kidney IAEA H-8, Human Hair NIES-5 and Tomato Leaves NBS-1573. Most of the results obtained for reference materials agreed with the certified values¹². Chinese autopsy samples of hair and liver were presented.     

胶束电动毛细管色谱法鉴别蓝色圆珠笔油墨

建立了用胶束电动毛细管色谱法（MECC）对纸上微量蓝色圆珠笔油墨进行分析鉴别的方法。研究了检测波长、电压、温度及电泳缓冲液中各组分浓度等因素对圆珠笔油墨分离的影响。当电压为25kV、柱温为25℃，检测波长为200nm时，以50mmol/L SDS-50mmol/L硼砂溶液（外加体积分数为45％的乙腈）为缓冲液，20种微量圆珠笔油墨样品样到了良好的鉴别。