TBP体系活度系数的测定和微扰理论的研究

在前人工作的基础上, 改进了液上空间气相色谱测活度系数的方法, 实验测定了TBP. 稀释剂和水形成的多个二元系、三元系和四元系的活度系数和密度. 选用的稀释剂有n-C_6H_(14)、n-C_7H_(16)、n-C_8H_(18)、C_6H_6、cy-C_6H_(12)、CCl_4和CHCl_3. 在Pierotti理论的基础上, 采用新的硬球作用表达式和径向分布函数, 并计及分子间的排斥能、色散能、取向能和诱导能, 建立了简单的活度系数模型, 并用于TBP和稀释剂体系的计算. 从二元系回归得到的分子参数较好地预测了三元系的活度系数.     

水中超痕量汞的富集与测定

利用合成的巯基含量为2.2～2.5%的高巯基粉状巯基棉,对水中超痕量汞进行富集测定。流速可达100mL·min~(-1),检出限为0.5×10~(-12),加标回收率为90～104%。     

THE REACTION OF AROMATIC ALDEHYDES WITH p-NITROBENZYLLIBUTYLTELLURONIUM BROMIDE BY PHASE TRANSFER CATALYSIS

Under the condition of solid-liquid phase transfer catalysis,olefins were obtained by the reaction of p-nitrobenzyldibutyltelluroniumbromide with aromatic aldehyde.Under the condition of liquid-liquid phasetransfer catalysis,however,different products were obtained due to thereactivity of different bases or aldehydes.     

Converting the sacrificial DNA repair protein N-ada into a catalytic methyl phosphotriester repair enzyme

Mutation of the active-site residue Cys38 of N-Ada converts it from a sacrificial DNA repair protein to an enzyme that uses methanethiol as an external sacrificial reagent to repair DNA methyl phosphotriesters catalytically.     

Electrochemical studies on the interaction of heparin with crystal violet and its analytical application

In this paper, crystal violet (CV) was used to determine heparin concentration by linear sweep voltammetry on a dropping mercury electrode (DME). In Britton-Robinson (B-R) buffer solution, pH 3.0, CV had a well-defined second-order derivative linear sweep voltammetric reductive wave at −0.74 V (vs. SCE). After the addition of heparin to the CV solution, the reductive peak current decreased greatly with the positive movement of the peak potential and without appearance of new peaks in the scanning potential range. Based on the decrease in the reductive peak current, a new voltammetric method for the determination of heparin was established. The conditions for the interaction and the electrochemical detection were optimized, and interfering substances were investigated. Under the optimal conditions, the decrease in reductive peak currents of CV was proportional to heparin concentration in the range 0.1–8.0 mg/L with the linear regression equation Δip″(nA) = 400.42 + 1563.11c (mg/L), (n = 14, γ = 0.993). The detection limit was 0.092 mg/L. This new method was further successfully applied to the determination of heparin content in heparin sodium injection samples with satisfactory results. The binding ratio and binding mechanism were also studied by the electrochemical method. The text was submitted by the authors in English.     

Spectrophotometric and Voltammetric Studies on the Interaction of Heparin with Phenosafranine

The interaction of phenosafranine （PSF） with a glycosaminoglycans of heparin （Hep） in aqueous solution has been characterized by UV-Vis absorption spectrophotometry and cyclic voltammetry in pH 1.5 Britton-Robinson （B-R） buffer solution. The addition of Hep caused decrease of the absorbance of PSF at 532 nm and the redox peak current of PSF. The study showed that an supramolecular complex of PSF-Hep was formed because of the electrostatic attraction of negatively charged Hep with the positively charged PSF, which resulted in the decrease of the equilibrium concentration of PSF in solutions, and the decrease of the absorbance or the peak current of PSF. The stoichiometry of the Hep/PSF complex was further calculated by voltammetric data with the result of 1：1 complex.     

Improvement on Simultaneous Determination of Cr(III) and Cr(VI) by Capillary Electrophoresis and Chemiluminescence Detection

Chromiumexistsindifferentoxidationstatesingroundwater,industrialwastewater,seawater,andsoilofourenvironment1,2.Chromium(III)isanessentialtraceelementforhumans,requiredforthemaintenanceofnormalglucose,cholesterol,andfattyacidmetabolism.Ontheotherhand,watersolublechromium(VI),intheformCr2O72-orCrO42-,ishighlyirritatingandtoxictohumansandanimals3.Itsacutetoxiceffectsincludeanimmediatecardiovascularshockandlatereffectsonkidney,liver,andblood-formingorgans.Therefore,itisnecessaryforriskassessme…     

Synthesis and properties of one-dimensional Ni(Ⅱ) and Ni(Ⅱ)Cu(Ⅱ) complexes linked by hydrogen bond

Four dithiooxalato (Dto) bridged one-dimensional Ni(ll) and Ni(ll)Cu(ll) complexes (Me6[14]dieneN4)Ni2(Dto)2) (1), (Me6[14]dieneN4)CuNi(Dto)2 (2), (Me6[14]aneN4)Ni2(Dto)2 (3), and (Me6[14]aneN4)CuNi(Dto)2(4), were synthesized. These complexes have been characterized by elemental analysis, IR, UV and ESR spectra. The crystal structure of complex 3 was determined. It crystallizes in the monoclinic system, space group C2/c with a = 2.2425(4) nm, b = 1.0088(2) nm, c=1.4665(3) nm, β= 125.32(3)° ;Z=4; R = 0.076, Rw = 0.079. In the complex, Ni(1) coordinates four sulphur atoms of two Dto ligands in plane square environment. Ni(2) lies in the center of mac-rocyclic ligand. For Dto ligand, two sulphur atoms coordinate Ni(1), and O(1) coordinates Ni(2) and forms weak coordination bond. O(2) is linked to N(2) of macrocyclic ligand through hydrogen bond.     

Nitrophenol Derivatives Oxidized by Cerium(IV) Ammonium Nitrate (CAN) and Their Cytotoxicity

Oxidation of a series of phenols with cerium(IV) ammonium nitrate (CAN) in acetonitrile under mild conditions yields the mixture of corresponding nitrophenols. In the cases of methylphenols and hydroxy ‐carboxylic acids, the steric effect may reduce the nitration reaction. Compounds 3a and 4b showed selective activities to Hep 3B and Hep G2 cancer cell lines, respectively. Compound 2c showed selective activities to Hep G2 and MDA‐MB‐231 cancer cell lines. Furthermore, compound 10b showed selective activities to Hep G2, Hep 3B, MCF‐7 and MDA‐MB‐231 cancer cell lines.     

Discovery of a small molecule that inhibits the interaction of anthrax edema factor with its cellular activator, calmodulin

The catalytic efficiency of adenylyl cyclase activity of edema factor (EF) from Bacillus anthracis is enhanced by approximately 1000-fold upon its binding to mammalian protein calmodulin (CaM). A tandem cell-based and protein binding-based screen of a 10,000 member library identified a molecule that inhibits the EF-CaM interaction and therefore the adenylyl cyclase activity. A combination of fluorescence spectroscopy and photolabeling studies showed that the molecule targets the CaM binding region of EF. A series of related compounds were synthesized and evaluated to identify one compound, 4-[4-(4-nitrophenyl)-thiazolylamino]-benzenesulfonamide, that maintained activity against EF but showed minimal toxicity to two cultured cell lines. This compound represents an important reagent to study the role of EF in anthrax pathology and may represent a drug lead against anthrax infection.