职业性铅接触对血压影响的研究

对１１８名铅接触工人及１０８名对照组工人的血压研究发现，在血铅为４４．２６μｇ／ｄＬ时，铅接触工人的收缩压显著高于对照组，分组研究发现，收缩压在级组剂量－反应关系趋势，在血铅３０．２０μｇ／ｄＬ，收缩压显著高于对照组，多元逐步回归分析发现，在控制一些其他影响血压的因素后，铅接触工人的血铅水平与收缩压和舒张压均有剂量－反应关系。     

VIB金属蝎型配合物(Scorpionate)的研究进展

综述了VIB金属(Mo、W)多吡唑硼配合物近年来的研究进展。详细地叙述了第二代多吡唑硼配体的合成与表征。     

镍电极开路电位测定微量硼氢根离子

实验采用循环伏安法，用镍电极代替铂铑等贵金属电极测定了碱性体系中不同硼氢根离子浓度下的开路电位，得出了研究电极的开路电位（-0．355～-0．280vs.SCE／V）与微量硼氢根离子浓度的对应关系，并用于监测电解偏硼酸钠制备硼氢化钠体系中微量硼氢根离子，同时计算了该方法的误差。结果表明，测量结果的相对标准偏差为2．2％；回收率为98．4％。该法简单、快速，可测定10^-5～10^-3mol／L范围的硼氢根离子浓度。     

Screening and analysis of bioactive compounds with biofingerprinting chromatogram analysis of traditional Chinese medicines targeting DNA by microdialysis/HPLC

Biofingerprinting chromatogram analysis, which is defined as the comparison of fingerprinting chromatograms of the extract of traditional Chinese medicines (TCMs) before and after the interaction with biological systems (DNA, protein, cell, etc.), was proposed for screening and analysis of the multiple bioactive compounds in TCMs. A method of microdialysis sampling combined with high performance liquid chromatography (HPLC) was applied to the study of DNA-binding property for the extracts of TCMs. Seven compounds were found to bind to calf thymus DNA (ct-DNA) from the TCMs of Coptis chinensis Franch (Coptis), but only three ones from Phellodendron amurense Rupr. (Phellodendron) and none from Sophoraflavescens Ait. (Sophora) to bind to ct-DNA, respectively. Three of them were identified as berberine, palmatine and jatrorrhizine and their association constants (K) to ct-DNA were determined by microdialysis/HPLC. Competitive binding behaviors of them to ct-DNA were also investigated.     

CO2＋H2制含氧化合物的研究

作为自然界中含有丰富碳源的CO_2,经过催化加氢制含氧化合物的研究,近年来为人们所关注,特别是CO_2加氢制甲醇.从CO_2出发制含氧化合物其前景是诱人的,则可利用碳和氧得到化学品,二则减少了自然界中的CO_2含量,有益于环境保护.本文对Cu-Zn系和Rh-V系催化剂进行初步考察.     

Neomycin binding to Watson-Hoogsteen (W-H) DNA triplex groove: a model

Neomycin is the most effective aminoglycoside (groove binder) in stabilizing a DNA triple helix. It stabilizes TAT, as well as mixed base DNA triplexes, better than known DNA minor groove binders (which usually destabilize the triplex) and polyamines. Neomycin selectively stabilizes the triplex (in the presence of salt), without any effect on the DNA duplex. (1) Triplex stabilization by neomycin is salt dependent (increased KCl and MgCl(2) concentrations decrease neomycin's effectiveness, at a fixed drug concentration). (2) Triplex stabilization by neomycin is pH dependent (increased pH decreases neomycin's effectiveness, at a fixed drug concentration). (3) CD binding studies indicate approximately 5-7 base triplets/drug apparent binding site, depending upon the structure/sequence of the triplex. (4) Neomycin shows nonintercalative groove binding to the DNA triplex, as evident from viscometric studies. (5) Neomycin shows a preference for stabilization of TAT triplets but can also accommodate CGC(+) triplets. (6) Isothermal titration calorimetry (ITC) studies reveal an association constant of approximately 2 x 10(5) M(-)(1) between neomycin and an intramolecular triplex and a higher K(a) for polydA.2polydT. (7) Binding/modeling studies show a marked preference for neomycin binding to the larger W-H groove. Ring I/II amino groups and ring IV amines are proposed to be involved in the recognition process. (8) The novel selectivity of neomycin is suggested to be a function of its charge and shape complementarity to the triplex W-H groove, making neomycin the first molecule that selectively recognizes a triplex groove over a duplex groove.     

Spectrofluorimetric determination of thiols by use of N[P-(2-benzoxazolyl)phenyl]maleimide

The weak fluorescence of N-[P-(2-benzoxazolyl)phenyl]maleimide (BOPM) can be greatly enhanced by thiol-containing compounds. A sensitive and simple spectrofluorimetric method based on the use of BOPM has been developed for the determination of thiols such as cysteine (Cys) and reduced glutathione (GSH). Calibration plots were linear in the concentration range from 0 to 1.6 x 10(-7) mol L(-1) for Cys and 0 to 1.7 x 10(-7) mol L(-1) for GSH. The detection limits (3a) were 2.36 x 10(-10) mol L(-1) for Cys and 1.49 x 10(-10) mol L(-1) for GSH. Many other amino acids (present at 100-fold greater concentrations) did not interfere with the determination. The proposed method has been used for the determination of Cys in protein hydrolysate and cystine electrolyte or GSH in serum, with recoveries of 95.4-103.7%.     

Filter-based microfluidic device as a platform for immunofluorescent assay of microbial cells

A filter-based microfluidic device was combined with immunofluorescent labeling as a platform to rapidly detect microbial cells. The coin-sized device consisted of micro-chambers, micro-channels and filter weirs (gap = 1-2 microm), and was demonstrated to effectively trap and concentrate microbial cells (i.e., Cryptosporidium parvum and Giardia lamblia), which were larger in size than the weir gap. After sample injection, a staining solution containing fluorescently-labeled antibodies was continuously provided into the device (flow rate = 20 microl min(-1)) to flush the microbial cells toward the weirs and to accelerate the fluorescent labeling reaction. Using a staining solution that was 10 to 100 times more dilute than the recommended concentration used in a conventional glass method, those target cells with a fluorescent signal-to-noise ratio of 12 could be microscopically observed at single-cell level within 2 to 5 min prior to secondary washing.     

The deformation of103Nb

Tie half-lives of 8 low lying levels of¹⁰³Nb have been determined at the fission-product separator JOSEF. A B-- triple-coincidence method was used which consists in a measurement of the time delay between the feeding of the levels through the B^– decay of¹⁰³Zr and their decay, in coincidence with a tagging ray, with plastic, BaF₂ and Ge detectors, respectively. Most of the investigated levels are members of the three known rotational bands based on the ground state and the 164 and 248 keV levels. The deformation B_q=0.31(3) of¹⁰³Nb could be deduced from the half-life data. The half-lives are well reproduced through calculations in the frame of the Nilsson model.The authors thank Dr. T. Seo for valuable advise in connection with the Nilsson-model calculations.