NMR Dynamic Studies in Living Systems

IntroductionApplications of nuclear magnetic resonance(NMR) spectroscopy in the study of living systemsrepresent an ever-expanding area of researchactively pursued in many universities and researchinstitutions[1 ] .The interestin studying living cellswith NMR techniques stemmed from the exchangeexperiments of human blood cells in D2 Operformed by Odeblad et al.in the mid-1 95 0 s[2 ] .Continued interest in defining and explaining theproperties of water in biological tissue from themid-1 96…     

苯甲酸溶剂效应的NMR考察

本文通过实验数据总结出苯甲酸溶液的化学位移δ与溶剂的介电常数ε之间存在着如下的直线方程:1/δ=A+Blgε表明,凡偏离此直线的溶液,必存在着溶质与溶剂间的分子间氢键的作用。本文还对属于这种性光的二氧六环与呲啶溶液的谱图作了仔细的讨论。     

ChemOffice在化学中的应用

介绍化学软件ChemOffice2002在化学中的应用,包括进行化学计算,推测核磁共振图谱和计算物理化学属性。     

13C NMR分析超临界CO2中合成的PAN的立构规整度

采用^13C NMR分析技术，将超临界CO2下AN沉淀聚合的立体特性(以下简称CO2-PAN)与AN水相沉淀自由基聚合及AN水相悬浮自由基聚合进行了比较，在五单元组立构序列的水平上讨论了超临界CO2中AN沉淀聚合的统计链增长模型。研究表明CO2-PAN的链增长过程符合Bernoulli统计模型，其立构规整性是完全无规的。并认为，与其他两种PAN相比，CO2-PAN等规立构规整度偏低的原因是由于所采用的CO2溶剂的非极性效应所致。     

Confirmation of sex pheromone biosynthesis from (16-D3)palmitic acid in the turnip moth using capillary gas chromatography

Summary (16-D₃)palmitic acid was applied topically to pheromone glands of the turnip moth. After incubation omega labeled analogues of fatty acid methyl esters and acetates were identified by gas chromatography with flame ionization detection and selected ion monitoring. The pheromone components (Z)-5-decenyl, (Z)-7-dodecenyl- and (Z)-9-tetradecenyl acetate were all biosynthesized from palmitic acid along a common pathway.     

Paracelsin; characterization by NMR spectroscopy and circular dichroism,and hemolytic properties of a peptaibol antibiotic from the cellulolytically active mnoldTrichoderma reesei. Part B

Summary Paracelsin, a hemolytic and membrane active polypeptide antibiotic of the peptaibol class which is excreted by the moldTrichderma reesei, was obtained by a simplified and isolation procedure utilziing hydrophobic adsorber resin. Investigation by¹³C nuclear magnetic resonance spectroscopy and circular dichroism revealed considerable helical portions in solution, and the very recently accomplished sequence determination of paracelsin allows the discussion of the results with regard to the closely related analogues, alamethicin and suzukacillin. A selective cleavage of the peptide was achieved by careful treatment with various acids, and a buffer of pH 8.25 and of high ionic strength made possible the quantitative determination of the C-terminal phenylalaninol released by means of ion-exchange chromatography. The significance of the production of paracelsin and related mycotoxins of the peptaibol class, exhibiting various kinds of biological activity, is discussed with respect to the extensive effort being made towards biotechnological applications of species, strains and cellulolytically highly active mutants of the fungusTrichoderma.Presented in part at the 5th European Symposium on Animal, Plant and Microbial Toxins, Hannover, August 29–September 2, 1983 and a lecture given at Ciby-Geigy/Basel in March 1984.Acknowledgment. We thank I. Ackermann for excellent and skilled technical assistance and gratefully acknowledge the help of R. Ratz for support in CD spectroscopy.     

固态高聚物的固体高分辩~(13)C核磁共振研究

本文描述了固体高分子在磁场中的行为.用固体高分辨~(13)C 核磁共振(NMR)研究了不同条件下结晶聚乙稀的多相结构.利用化学位移、各相中弛予时问T_(■e),T~(2■)的不同和不同的脉冲序列对结晶、界面、非晶相成分能够分别进行选择性观测.对定量测出的各成分量进行了讨论,并得到界面相厚度,和Flory 最近提出的格子模型理论计算值比较的结果说明:从较低分子量及稀溶液结晶的聚乙稀界面层厚度值和Flory 理论计算值一致.     

Folded-chain lamellae interphase in flexible polymers

In a semicrystalline aggregate of flexible chain polymers, a large amount of the adjacent regularly-folded tiny lamellae coexists with the amorphous phase whose chains have only random spatial arrangement. This 'crystalline-noncrystalline' two-phase model has been widely accepted and used to describe the structure and properties of polymers in condensed state. The crystalline morphology of PE prepared by various methods have been     

合成药物盐酸洛非西定及其中间体的结构鉴定

本文用ＩＲ，ＮＭＲ，ＭＳ及ＵＶ四大谱对合成药物盐酸洛非西定的化学结构进行了研究，四大谱表明了该化合物与中间体的不同结构特征，确认了该化合物的化学结构。