非水介质毛细管电泳电导检测舒血宁片中槲皮素含量

以甲醇：水＝70：30的体系为分离介质，柠檬酸－三（羟甲基）氨基甲烷（Citric acid-Tris)为支持电解质，使用电导检测，对槲皮素及其制剂舒血宁片进行了毛细管电泳分离检测，对电泳介质的种类、浓度、表观pH值以及操作电压和进样时间对分离的影响进行了研讨，并对分离检测机理进行了探讨。建立的测定槲皮素的方法的线性范围为：8．0－160．0mg/L；峰面积的RSD（n=6)为1．7％，检出限为1．0mg/L；样品加标回收率为92．8％－98．2％。     

Polyarylate–polystyrene block copolymer from macro-azoinitiator: Synthesis and its thermal properties

A macro-azoinitiator containing polyarylate segment and azo group was prepared by the solution polycondensation of azobiscyanopentanoyl chloride and hydroxy-terminated polyarylates having viscosity-average molecular weights of 6200, 8100, and 12 400. These macro-azoinitiators were used in the radical polymerization of styrene to synthesize polyarylate-polystyrene block copolymers. Thermal properties measured by the differential scanning calorimetry indicated the phase separated morphology of the block copolymers except at low molecular weight of the block constituents. © 1993 John Wiley & Sons, Inc.     

螯合型二甘醇钛酸酯的合成及其催化性能研究

报导了两种新的螯合型二甘醇钛酸酯的合成方法，进行了ＩＲ和ＵＶ鉴定，并作为酯化反应催化剂催化合成了邻苯二甲酸二辛酯。研究了酯化反应转化率与反应时间、反应温度及催化剂用量的关系，探讨了催化剂结构与催化性能的关系。     

Use of the64Ni(36S,34,35Si)66,65Zn reactions to measure the masses of34Si and35Si

The ground-state masses of³⁵Si and³⁴Si have been measured using the reactions⁶⁴Ni(³⁶S,^35,34Si)^65,66Zn at a³⁶S beam energy of 198 MeV.^34,35Si¹⁴⁺ ions were analysed and identified in a QMG/2 magnetic spectrometer and gas-filled focal-plane detector. The experimental mass excess of³⁵Si was determined to be ?14.58± _0.12 ^0.07 MeV while that of³⁴Si was measured as ?19.961±0.034 MeV. A comparison is made with the results of mass model predictions.     

Energetic and topological analysis of the reaction of Mo and Mo2 with NH3, C2H2, and C2H4 molecules

The Density functional theory has been applied to characterize the structural features of Mo(1,2)-NH(3),-C(2)H(4), and -C(2)H(2) compounds. Coordination modes, geometrical structures, and binding energies have been calculated for several spin multiplets. It has been shown that in contrast to the conserved spin cases (Mo(1,2)-NH(3)), the interaction between Mo (or Mo(2)) and C(2)H(4) (or C(2)H(2)) are the low-spin (Mo-C(2)H(4) and -C(2)H(2)) and high-spin (Mo(2)-C(2)H(4) and -C(2)H(2)) complexes. In the ground state of Mo(1,2)-C(2)H(4) and -C(2)H(2), the metal-center always reacts with the C-C center. The spontaneous formation of the global minima is found to be possible due to the crossing between the potential energy surfaces (ground and excited states with respect to the metallic center). The bonding characterization has been performed using the topological analysis of the Electron Localization Function. It has been shown that the most stable electronic structure for a pi-acceptor ligand correlates with a maximum charge transfer from the metal center to the C-C bond of the unsaturated hydrocarbons, resulting in the formation of two new basins located on the carbon atoms (away from hydrogen atoms) and the reduction of the number of attractors of the C-C basin. The interaction between Mo(1,2) and C(2)H(4) (or C(2)H(2)) should be considered as a chemical reaction, which causes the multiplicity change. Contrarily, there is no charge transfer between Mo(1,2) and NH(3), and the partners are bound by an electrostatic interaction.     

The aza-xylylene Diels-Alder approach for the synthesis of naturally occurring 2-alkyl tetrahydroquinolines

The recently discovered intramolecular aza-xylylene Diels-Alder reaction, based on a 1,4-dehydrohalogenation reaction, was extended in terms of substrates and leaving groups allowing the assembly of tetrahydroquinolines in two synthetic steps. Intramolecular cleavage of a thiocarbamate using triphenylphosphine and tetrachloromethane (Appel conditions) to give chloromethyl phenylisocyanate has been presented for the first time. The synthetic feasibility of this process was demonstrated in the first total syntheses of the alkaloids rac-Angustureine and 1-methyl-2-propyltetrahydroquinoline.     

Thermal Decomposition Kinetics of the Zn(II) Complex with Norfloxacin in Static Air Atmosphere

The thermal decomposition of Zn[NFA]₂5H₂O (NFA=C₁₆H₁₈FN₃O₃, norfloxacin) and its kinetics were studied under non-isothermal conditions in air by TG-DTG and DTA methods. The intermediate and residue for each decomposition were identified from the TG curve. The non-isothermal kinetic data were analyzed by means of the Achar method and the Madhusudanan-Krishnan-Ninan (MKN) method. The possible reaction mechanisms were investigated by comparing the kinetic parameters. The kinetic equation for the second stage can be expressed as d/dt=Aexp(–E/RT)(1–).This revised version was published online in November 2005 with corrections to the Cover Date.     

THE ULTRAVIOLET DOSE DEPENDENCE OF NON-MELANOMA SKIN CANCER INCIDENCE

Abstract— We correlate annual ultraviolet dose estimates with age specific and age adjusted incidence data for non-melanoma skin cancer in the United States, United Kingdom, Canada and Australia. We first examine (1) a reciprocity or photographic model in which incidence rates (R) are related to exposure (E) which is the product of age (T) and annual dose (D). We also test several models which violate reciprocity including models identified by the labels: (2) Dose potency; (3) Double cause; (4) Age-exposure and (5) separable. Our analyses together with the recent National Cancer Institute study favors the age-exposure model and/or the double cause models. All models lead to biological amplification factors (defined as the ratio of the percent increase in skin cancer incidence due to a 1% increase in dose) greater than unity. For the U.S. we find the biological amplification to be approximately 1.8 for the population center but greater in regions of higher UV annual dose, and less in regions of lower annual UV dose.     

Methodological modifications on quantification of phosphatidylethanol in blood from humans abusing alcohol,using high-performance liquid chromatography and evaporative light scattering detection

Background  

Phosphatidylethanol (PEth) is an abnormal phospholipid formed slowly in cell membranes by a transphosphatidylation reaction from phosphatidylcholine in the presence of ethanol and catalyzed by the enzyme phospholipase D. PEth in blood is a promising new marker of ethanol abuse depending on the high specificity and sensitivity of this marker. None of the biological markers used in clinical routine at the present time are sensitive and specific enough for the diagnosis of alcohol abuse.     

Molecular orbital interpretation of X-ray emission spectra of ClCN and ONCl

Ab initio as well as semi-empirical SCF MO calculations are presented for ClCN and ONCl. The relative intensities for Cl Kβ emission in the two molecules were calculated. The calculated spectra from the ab initio wavefunctions are in excellent agreement with experiments.