AFFINITY LABELLING OF E.coil LEUCYL-tRNA SYNTHETASE WITH 3''''-OXIDIZED tRNA~(Leu)

The E.coli leucyl-tRNA synthetase (E. C. 6. 1. 1. 4) was specifically labelled with 3'-oxidized tRNA~(Leu) (tRNA_(ox)~(Leu)).The procedure involves a Schiff's base formation and its subsequent reduction by sodium cyanoborohydride. Stoichiometric inactivation of aminoacylation was achieved with the incorporation of 1 mol of tRNA_(ox)~_(Leu) per mol LeuRS.On the other hand, the amino acid activation activity of LeuRS-tRNA_(ox) complex was partially inhibited. After extensive digestion of the complex by pancreatic ribonuclease, the amino acid activation activity was fully recovered, while the aminoacylation activity was not restored at all.The results suggest that the active sites responsible for the activities of LeuRS correlate with each other as well as differ from each other.     

掺铬铝酸钇红色颜料的合成、结构和性能表征

研究了高温固相合成制备掺铬铝酸钇红色颜料的方法，着重考察了灼烧温度（1000-1400℃）、灼烧时间（1-2h）、主要原料配比（Al／Y：1：0．5—1：1．5，Cr2O3％：0．3％-5％）等实验条件对产物结构和色泽的影响。XRD等方法对样品进行的相态分析表明，主相为铝酸钇石榴石相；运用反射光谱对红色颜料的色泽进行了反射峰位和相关强度的表征。当Y2O3：Al2O3摩尔比为1：1，掺杂3％的Cr2O3作显色剂，在少量矿化剂存在时，在1300℃下灼烧1 h，得到了色坐标为x=0．577，Y=0．401的红色陶瓷颜料。     

ISOLATION,CHARACTERIZATION AND EXPRESSION OF THE COMPLEMENTARY DNA FOR HUMAN TUMOR NECROSIS FACTOR (TNF-α)

A cDNA for human TNF-α (615bp) was isolated by means of polymerase chain reaction (PCR) using first strand cDNA from PMA-induced HL-60 cells as template. The result from sequencing the 615 bp cDNA fragment indicated that it corresponded to the entire sequence of mature human TNF coding region. Direct expression of mature human TNF was achieved using a plasmid pHT-1 constructed by ligation of the cDNA and a synthetic DNA. The IPTG-induced bacterial product (hTNF) showed cytotoxicity to mouse L-929 cells. The TNF activity was further identified by neutralization of a specific monoclonal antibody against human TNF-α. Approximately 80,000 units of activity were detected per ml of culture at A600=2.     

Ti-Al-Y三元系相图研究

稀土元素在冶金工业中作为添加剂、变质剂有良好的效果,它对钢铁、铜、铝和难熔金属具有明显的净化、细化和强化效果。本文用金相观察、X射线相分析、电子探针成分分析及显微硬度测定方法研究了Ti-Al-Y系相图,并建立了550℃及1000℃等温截面(图1、2)。     

乙烯基聚硅氧烷共聚反应竞聚率的测定及其对复合粒子形态的影响

用Ｆｉｍｅｍａｎ－Ｒｏｓｓ法处理数据，测定了乙烯基聚硅氧烷（ＳＶ）与苯乙烯（ＳＴ）、甲基丙烯酸甲酯（ＭＭＡ）和甲基丙烯酸正丁酯（ｎ－ＢＭＡ）的共聚反应的竞聚率，结果为ｒＳＴ＝１．４５和ｒＳＶ＝１．０８，ｒＭＭＡ＝０．７８和ｒＳＶ＝２．０１，ｒｎ－ＢＭＡ＝０．４６和ｒＳＶ＝３．４９．以含ＳＶ的乳液作为种子进行烯类单体的乳液聚合，单体和ＳＶ共聚反应对复合粒子的形态有很大影响。     

TEA-CO_2激光多光子解离2,2-二氯1,1,1-三氟乙烷分离氢氘同位素

本工作从CF_2ClCCl_2F经AlCl_3催化重排、铜粉催化与三乙醇胺反应得到CF_3CHCl_2。经与重水交换得到CF_3CDCl_2(D丰度93.5％),二者红外光谱有很大差别,前者在842cm~(-1)处有强吸收;后者在842cm~(-1)的吸收大为减弱,而在944cm~(-2)、986cm~(-1)出现C-D键的强吸收。944cm~(-1)处的吸收恰与CO_2激光器输出P(20)支线相匹配,致使激光一次脉冲(～3焦耳/脉冲)的照射,可分解8.9％(CF_3CDCl_2压力为9.6乇),而CF_3CHCl_2的吸收与CO_2激光器输出波长不匹配,辐照不引起分解。利用此原理,将人工配制CF_3CHCl_2:CF_3CDC1_2=4:1的2乇样品,用激光辐照,可选择性分解CF_3CDCl_2,达到同位素富集的效果。目前已获得辐照100次脉冲,分离因数     

非放射性多碘标记-偶合催化反应的极谱免疫分析研究

提出非放射性多碘标记-偶合催化反应的极谱免疫分析新体系,该体系以人白蛋白(HSA)作模型抗原,用含4个非放射性碘有机化合物藻红B(EB)经一步化学反应标记HSA.该标记方法简便,条件温和.所得标记物中EB:HSA摩尔比为12:1.用本方法获得的标记蛋白质含碘量远高于其它现有方法.利用标记的含碘抗原对As(Ⅲ)-Ce(Ⅳ)反应的催化作用,用极谱法检测底物中 As(Ⅲ)量变化,建立了异相竞争极谱免疫分析新方法.HSA可测浓度范围为1～200μg/mL,检测限为0.66μg/mL.提出的新体系也适用于其他蛋白质的免疫分析.     

二卤卡宾和苯甲醛反应机理的理论研究 ─ ylide 中间体的结构及反应特性

本文以SCF-MNDO方法进行计算, 获得了二氯卡宾与苯甲醛反应所形成的二卤羰基ylide中间体各异构体的构型、能量、电荷分布及其它有关数据, 并根据计算结果研究了ylide各异构体的不同化学行为, 进一步探讨了二卤卡宾与苯甲醛的反应机理。     

铈对光亮镀锌层耐蚀性的影响

研究了铈对光亮镀锌层耐蚀性的影响，发现当镀液中铈盐浓度为０．１～０．２ｇ／Ｌ时，镀层耐蚀性提高约３５％。化学分析及Ｘ射线衍射试验表明，微量铈进入了镀层，并促使晶面产生取向效应。对镀液的若干性能测试证明，微量铈的加入，对基液的性能基本无影响。     

Construction of a Novel 2D Polymer [Co（dmpzm）（dca）2]∞ from Reaction of a Mononuclear Complex [Co（dmpzm）Cl2] with Sodium Dicyanamide （dca） [dmpzm=bis（3,5-dimethylpyrazolyl）methane]

Reaction of COC12.6H20 with equimolar bis（3,5-dimethylpyrazolyl）methane （dmpzm） produced a mononuclear adduct [Co（dmpzm）Cl2] （1）. Treatment of 1 with sodium dicyanamide （dca） afforded a polymeric complex [Co（dmpzm）（μ-dca）2]∞ （2）. 1 and 2 were characterized by elemental analysis, IR spectra, thermogravimetric analysis and single-crystal X-ray diffraction. The cobalt atom in 1 adopts a distorted tetrahedral coordination geometry, bound to two N atoms of one dmpzm and two Cl atoms. Complex 2 has a 2D brick-wall network （extended along the bc plane） in which the { [Co（dmpzm）（μ-dca）]2} n^2n＋ chains are interconnected by pairs of μ-dca anions along the c axis. The magnetic properties of 1 and 2 were also investigated.