5-Br-PADAP直接光度法测定发锌

为建立一种简便、快速、灵敏的直接光度法测定发锌,将发样经无机化处理后,以5-Br-PADAP作为显色剂,在表面活性剂存在下直接光度法测定头发锌含量。结果表明,该法线性范围为0～612.0μmol/L,回收率为99.4％～102.4％,批内变异系数(CV)和批间变异系数分别为0.027和0.033。55例健康人头发锌含量为171.8±67.5μg(x±2s)。可见5-Br-PADAP直接光度法测定发锌具有操作简单、快速灵敏、结果可靠的优点,适合临床应用。     

A concise synthesis of nornitidine via nickel- or palladium-catalyzed annulation

A concise method to synthesize benzo[c]phenanthridine alkaloid, nornitidine, was developed utilizing nickel- or palladium-catalyzed iminoannulation of an internal alkyne. The advantages of this strategy included readily available starting materials, inexpensive reagents, short reaction steps, and good yields.     

二苄亚砜硝酸钕的晶体结构

二苄亚砜硝酸钕Nd(NO_3)_3·[(C_6H_5CH_2)_2S0]属三斜晶系,P1空间群,晶胞参数:a=9.835(2),b=12.445(2),c=19.971(5)A,α=104.13(2)°,β=90.34(2)°γ=74.96(1)°Z=2。晶体结构用重原子法解出,经最小二乘修正后R因子为0.031。钕离子由九个氧配位,形成稍歪扭的三帽三方棱柱配位多面体,其中一个三角面由三个二苄亚砜(DBSO)提供的氧形成,其他氧原子则由硝酸根提供。平均Nd-O(DBSO)=2.379A,Nd-O(NO_3)=2.536A。     

瑞香素稀土配合物的合成和性质

自六十年代以来陆续发现稀土化合物具有一系列特殊的药效作用 ,使稀土元素在药物上的应用展现出广阔前景。目前 ,已有不少稀土化合物应用于临床 ,如抗凝血药物 3 磺酸异烟酸钕、左旋糖酸镨、钕混合物 ;消炎药水杨酸钐等。合成具有生物活性配体的稀土配合物是寻找有效稀土药物的一条途径。瑞香素是一具有抗菌、抗炎、抗凝血等生物活性的香豆素类化合物 ,其分子结构为 :稀土与香豆素类的配合物的合成与性质研究己有不少报道[1,2 ] 。为了进一步研究这类配合物的性质和生物活性 ,我们合成了六种瑞香素稀土配合物。1　实验部分1 .1　仪器及试剂…     

计算机Monte Carlo法模拟自由基交联共聚网络结构的增长

本文成功地用MonteCarlo方法模拟了以画面方式表示的苯乙烯-二乙烯苯交联共聚反应中大分子链增长、支化及交联的进化情况，并给出了相应的转化率，以定量模型的方式描述了该类反应。     

纳米CeO2的形貌控制与表征

以Ce(NO3)3·6H2O和(NH4)2CO3为沉淀源,利用柠檬酸作为络合剂和分散剂,实现了对CeO2前驱体的形貌和尺寸控制,并采用TEM,TGA和XRD等方法对前驱体及其热分解所得纳米CeO2的形貌及结晶性等进行了表征.结果表明,随着柠檬酸加入量的提高,前驱体形貌从纳米线向类球形颗粒变化,焙烧生成的纳米CeO2颗粒的形貌具有明显继承性,所得CeO2属于立方萤石结构,且随焙烧温度的提高,晶化程度增大.     

肉桂酸类分子非线性光学效应的理论研究

计算了一系列肉桂酸（苯基丙烯酸）类化合物的二阶非线性光学系数，系统地研究了取代基的电子性质和取代位置对其非线性光学性质的影响，并且探讨了该类化合物的饱和取代效应．研究表明，该类化合物的非线性光学性质与其分子结构有着密切的关系．     

Analysis of flavonoids in <Emphasis Type="Italic">Ginkgo biloba</Emphasis> L. and its phytopharmaceuticals by capillary electrophoresis with electrochemical detection

A high-performance capillary electrophoretic (CE) method with electrochemical detection (ED) has been developed for determination of the pharmacologically active flavonoids in Ginkgo biloba L. and phytopharmaceuticals containing its extract. Epicatechin, catechin, rutin, apigenin, luteolin, and quercetin are important flavonoids in this plant. Operated in a wall-jet configuration, a 300 micro m diameter carbon-disk electrode was used as working electrode with good response to the six analytes at +1000 mV (relative to the SCE). Under the optimum conditions, the analytes were separated within 22 min in a borax buffer (pH 9.0). Excellent linearity was obtained over two orders of magnitude and detection limits (S/N=3) ranged from 1.4 x 10(-7) to 5.0 x 10(-7) g mL(-1) for all six analytes. The method was successfully used for assay of Ginkgo biloba L. and its phytopharmaceuticals after a relatively simple extraction procedure; the results obtained were satisfactory.     

用高效液相色谱手性固定相法拆分芳香仲醇及芳香乙二 醇类手性化合物

在ChiralcelOD和ChiralcelOJ两支多糖类手性固定相上，以各种不同配比的正己烷-异丙醇为洗脱剂对38种带有不同取代基的芳香仲醇及芳香乙二醇类手性化合物的对映体进行拆分，考察了这些外消旋体在这两支手性柱上的色谱行为。结果表明，扬长避短一柱对这些化合物的拆分能力与化合物取代基的性质和位置有关，这些化合物与手性固定相之间的氢键作用和π-π作用是影响手性拆分的重要原因。拆分方法已应用于潜手性酮不对称还原产物的光学纯度的鉴定，并取得了很好的效果。     

Effect of humidity on the adsorption kinetics of lung surfactant at air-water interfaces

The in vitro adsorption kinetics of lung surfactant at air-water interfaces is affected by both the composition of the surfactant preparations and the conditions under which the assessment is conducted. Relevant experimental conditions are surfactant concentration, temperature, subphase pH, electrolyte concentration, humidity, and gas composition of the atmosphere exposed to the interface. The effect of humidity on the adsorption kinetics of a therapeutic lung surfactant preparation, bovine lipid extract surfactant (BLES), was studied by measuring the dynamic surface tension (DST). Axisymmetric drop shape analysis (ADSA) was used in conjunction with three different experimental methodologies, i.e., captive bubble (CB), pendant drop (PD), and constrained sessile drop (CSD), to measure the DST. The experimental results obtained from these three methodologies show that for 100% relative humidity (RH) at 37 degrees C the rate of adsorption of BLES at an air-water interface is substantially slower than for low humidity. It is also found that there is a difference in the rate of surface tension decrease measured from the PD and CB/CSD methods. These experimental results agree well with an adsorption model that considers the combined effects of entropic force, electrostatic interaction, and gravity. These findings have implications for the development and evaluation of new formulations for surfactant replacement therapy.