聚酯型脂肪族和芳香族聚氨酯硬段结晶特性对比

本文利用DSC、IR、WAXD、PLM和SALS等实验手段,探讨了具有相同软段的聚酯型脂肪族和芳香族聚氨酯硬段结晶特性的差异,发现脂肪族聚氨酯的相分离速率极快,氢键主要在硬段间形成,因而对硬段的结晶过程影响不大;而芳香族聚氨酯的相分离速率较慢,软硬段间又能形成氢键,因而对硬段的结晶起了阻碍作用。     

有机溶剂化效应对多元络合物显色反应作用的研究(Ⅱ)——有机溶剂对络天青S在胶束相分配系数的影响

前文曾报道有机溶剂化效应对增敏体系微环境的影响。本文从物理-有机化学及胶体化学角度,用分光光度法测定在有机溶剂存在下,铬天青S(CAS)在胶束和溶液间的分配系数(K_D),并考察分配系数与显色反应灵敏度的关系。     

激光Raman光谱研究2,4己二炔-1,6二醇的双苯异氰酸酯的聚合——晶型对固相聚合活性的影响

用激光Raman光谱研究了三种不同晶型的2,4-已二炔-1,6二醇的双苯异氰酸酯(HDPU)的聚合,发现不同晶型的HDPU的聚合活性与其C=C伸缩振动频率的频移之间存在内在联系。这说明单体晶格与聚合物晶格的匹配是HDPU具有高的聚合活性的必要条件。     

超导相(Bi1.7Pb0.2In0.1)Sr2Ca2Cu3O10的制备和晶体结构研究

The superconducting phase(Bi_(1.7)Pb_(0.2)In_(0.1))Sr_2Ca_2Cu_3O_(10) with on-set T_c near 112K and zero resistivity at 95K has been prepared. The Unit cell is. body-centered tetragonal, space group I4/mmm, a=0.3.817(1) nm, c=3.704(1) nm. Chemical substitution of Pb and In in Bi—Sr—Ca—Cu—O series results in the growth of 2223 phase. The superconductivity and the formation mechanism are associated with the structural features.     

二（1,8—萘啶氮氧化物）合硝酸铜（Ⅱ）的晶体结构

1,8-萘啶氮氧化物(简写napyo)是一种配位能力较强的中性配体,关于它与金属离子形成的配合物已有报道.但工作主要集中在配合物的合成及性质的研究,它与金属离子形成的配合物的晶体结构至今未见报道.本工作旨在探讨1,8-萘啶氮氧化物与铜(Ⅱ)的配合物中配体与金属离子的配位情况以及铜(Ⅱ)的配位构型.     

国产滤纸室温燐光背景的考察和降低背景方法的研究

固体基质室温燐光法(SS-RTP)的检出限依赖于固体基质的RTP背景的高低。本文考察了七种国产滤纸在重原子存在时和不存在时的RTP背景。研究了各种降低滤纸背景的处理方法。研究结果表明,采用NaOH、β-环糊精、EDTA、乙醇和丙酮浸泡或煮沸滤纸,都能不同程度的降低滤纸背景,最大降低率为88％。KI、NaAc、Pb(Ac)_2、TlNO_3和Cscl等重原子可使滤纸背景有较大幅度的增强,而经处理的滤纸,RTP背景较未处理滤纸背景降低一倍以上,最大可降低94.5％。用NaOH溶液处理滤纸,不仅能有效地降低背景,而且能提高分析物的RTP信号。研究表明纤维素伴生物质——木素,可能是产生燐光背景的杂质之一。     

抗脂解活性的人参十四肽的结构预测

本文对抗脂解活性的人参多肽的结构进行了分析. 在一级结构的基础上预测了其二级结构含有较多的α螺旋, 后接一段无规卷曲. 应用分子力学方法, 结合晶体数据库信息, 计算了人参中抗脂解十四肽分子的相对构家能量和原子坐标, 模拟了构象能量优化过程, 得到了可能的最低能量构象. 并利用计算机分子图形技术建立了相应的人参抗脂解十四肽的三维分子模型. 模型的空间结构表明构象分析结果与二级预测的结论很好地相符。     

基态UC2分子的结构和势能函数

采用密度泛函理论(DFT)的B3LYP方法和相对论有效原子实势理论模型(RECP),对UC2分子可能的结构进行优化计算,得到UC2分子稳定构型为角形C-U-C(C2v);由微观可逆性原理,判断了UC2分子的离解极限;并且导出了基态UC2分子(X 5B1)的多体项展式势能函数,其势能面等值图展现了C-U-C(C2v)稳定结构;根据势能面等值图,讨论了C+UC(X 3П)反应和U+C2(X 1∑+g)反应的势能面静态特征.     

DNA microarray: a high throughput approach for methylation detection

We described a DNA microarray-based method combined with bisulphite treatment of DNA and regular PCR to examine hyper-methylation in promoter 1A of APC gene. A set of oligonucleotide probes were designed and immobilized on the aldehyde-coated glass slides for detecting the methylation pattern of 15 selected CpG sites in the region. The methylation status of 30 colorectal tumor samples have been examined by both of methylation-specific PCR (MS-PCR) and the present microarray method. The methylation pattern of the 15 CpG sites for the samples have been obtained with the microarray. A total of 19 samples out of 30 were methylated by microarray, in which five samples cannot be detected by MS-PCR due to the methylated CpG patterns not accordant to the MS-PCR primers. The detecting ratio for methylation of APC gene of colorectal tumor samples increased from 46.7% with MS-PCR to 63.3% with the microarray, which successfully demonstrated that DNA microarray-based method not only can obtained the methylation patterns for the related genes, but also decrease the false-negative results of methylation status by the conventional MS-PCR for the investigated genes.     

Development and validation of a liquid chromatography/tandem mass spectrometry procedure for the quantification of adefovir in human plasma

To investigate the pharmacokinetics of adefovir as an anti-hepatitis B virus drug, a sensitive and specific liquid chromatography/tandem mass spectrometry method was developed and validated. After a simple protein precipitation using methanol, the post-treatment samples were analyzed on a C(18) column interfaced with a triple-quadrupole tandem mass spectrometer using positive electrospray ionization. A structural analogue, PMPA, was used as the internal standard. The method was linear in the concentration range 0.25-100 ng/mL. The lower limit of quantification was 0.25 ng/mL. The intra- and inter-day relative standard deviation over the entire concentration range was 5.7% or less. The accuracy determined at three concentrations (0.75, 10 and 80 ng/mL for adefovir) was within +/-2.5% relative error. The method described here was successfully applied for the evaluation of pharmacokinetic profiles of adefovir after single oral administration doses of 5, 10 and 20 mg adefovir dipivoxil to ten healthy volunteers.