二、三分枝甘露糖簇衍生物的合成

采取一种有效途径合成了二、三分支的甘露糖簇分子．甘露糖经烯丙苷化、乙 酰基保护后，将其烯丙基的双键氧化得到带有羧基连接臂的甘露糖衍生物，然后再 分别与l，6-己二胺和三(2-氨乙基)胺进行缩合反应，最后脱掉保护基，得到二分 枝甘露糖簇化合物6和三分枝甘露糖簇化合物8．     

Molecularly imprinted sol-gel nanotubes membrane for biochemical separations

In this study, we report a simple procedure for applying molecular imprinting functional groups to the inner surfaces of the template-synthesized sol-gel nanotubes for chemical separation of estrone. The silica nanotubes were synthesized within the pores of nanopore alumina template membranes using a sol-gel method by simultaneous hydrolysis of a silica monomer-imprinted molecule complex and tetraethoxysilane (TEOS). A covalent imprinting strategy was employed by generating a sacrificial spacer through the reaction of the isocyanate group of 3-(triethoxysilyl)propyl isocyanate and a phenol moiety of estrone to form a thermally cleavable urethane bond. This allowed us to remove the imprinted estrone by simple thermal reaction and to simultaneously introduce functional groups into the cavity formed by the silica nanotubes. Experiments indicated that estrone could be bound selectively by such an approach and have a binding affinity of 864 +/- 137 (n = 3).     

2＇，3＇－O－异亚丙基－5＇－O－［N，N－二（2－氯乙基）磷酰胺基］核苷的合成

２＇，３＇－Ｏ－异亚丙基－５＇－Ｏ－［Ｎ，Ｎ－二（２－氯乙基）磷酰胺基］核苷的合成陈茹玉，迟国臣，陈小茹（南开大学元素有机化学研究所，天津，３０００７１）关键词核苷，亚磷酰化，抗肿瘤活性很多核苷类化合物具有很好的抗肿瘤、抗病毒等生物活性，某些化合物已...     

金属铜升温熔化过程的分子动力学模拟

采用分子动力学方法模拟了金属铜的升温熔化过程.原子间作用势采用FS (Finnis-Sinclair)势，结构分析采用双体分布函数(PCF)、均方位移(MSD)等方法.计算结果表明,在连续升温过程中，金属铜在1444 K熔化，在该熔化点的扩散系数为4.31×10－9 m2•s－1.上述结论与实验值相当接近，并且比之采用EAM镶嵌原子势所作模拟得到的结果更佳，说明FS势可以用来处理象液铜这样较复杂的无序体系.本文指出了升温速率在金属熔化过程中所起的作用.     

Trace lead measurement and on-line removal of matrix interference in seawater by isotope dilution coupled with flow injection and ICP-MS

Isotope dilution analysis method coupled with flow injection and inductively coupled plasma mass spectrometry (ID-FI-ICP-MS), enabled trace lead concentration in seawater to be determined and the high salt concentration in the matrix, such as Na⁺, Ca²⁺ and Mg²⁺, to be removed on-line. The operational parameters of the FI system including pH for the chelating reaction, concentration of 8-hydroxyquinoline-5-sulfonic acid (8-HQS), sample loading time and injection speed, washing time and speed, eluting acid concentration and eluting speed, and instrumental parameters for ICP-MS were optimized and selected. Accurate results could be achieved because the isotope ratios required can be precisely measured in the range of the eluting peak by means of ID-FI-ICP-MS. The 3σ detection limit was 0.204 ng ml⁻¹. The trace lead concentration of seawater in south Xiamen, China was 0.988 ± 0.039 ng ml⁻¹. The recoveries of spiked Pb standard in seawater and standard reference water (GBW 08607) were 97.9 and 101.0%, respectively, with a relative standard deviation of 0.98%. This method can be used to determine trace lead concentration in high salt matrix samples, and is especially useful when the eluting peaks do not have a Gaussian-distribution.     

2-十四烷基-DTPA及其钆(Ⅲ)螯合物的合成与表征(英)

Synthesis and characterization of the ligand, [2-tetradecyl-3,6,9-tris(carboxymethyl)-3,6,9-triazaundecan-1,11-dioic acid, H₅L] and its Gd(Ⅲ) chelate are described. Protonation constants for H₅L (lgK_i^H = 10.80, 8.40, 4.30, 2.80, 2.15) and the stability constant for GdL^2- (lgK_GdL^2-= 22.75) were determined by potentiometric titration and are similar with the related values of DTPA and Gd-DTPA respectively. The results obtained show that the basicity of the ligand and the stability constant of its Gd(Ⅲ) chelate are not obviously altered after introduction of a linear chain tetradecyl group at the terminal acetic acid residue of DTPA.