ALLOSTERIC REGULATION OF THE STATE OF ADENYLYLATION OF GLUTAMINE SYNTHETASE IN PERMEABILIZED CELL PREPARATIONS OF Rhoaopseudomonas sphaeroides

Following a freeze-thaw cycle, and the treatment of Rhodopseudomonas sphaeroides withthe nonionic detergent Lubrol PX, the permeabilized cell suspensions can be assayed directlyboth for the intracellular levels of glutamine synthetase and the state of adenylylation(i.e. the average number n of adenylylated subunits/dodecameric molecules). It seems that all components of the bicycle system are retained if cells grown with lowconcentrations of a?monia as the sole nitrogen source are used. The value of n was depend-ent upon the concentration of substrates (ATP, Pi) and allosteric effectors (ATP, gluta-mine and α-ketoglutarate) of adenylyltransferase. The value of n affected by UTP, thespecific substrate of the uridylyltransferase shows first the evidence that the bicycle cascadecontrol system studied in Escherichia coli may exist in this phototrophic bacterium.     

金属离子对中位─四（4─N甲氧羰甲基吡啶）卟啉表面增强拉曼光谱的影响

研究了金属离子对吸附在银胶表面的中位－四（４－Ｎ甲氧羰甲基吡啶）卟啉表面增强拉曼光谱的影响。结果表明，中位－四（４－Ｎ甲氧羰甲基吡啶）卟啉可发生金属离子取代反应。金属离子嵌入卟啉大环，吸附在银胶表面的中位－四（４－Ｎ甲氧羰甲基吡啶）卟啉转变为金属配合物。给出了各种金属配合物主要拉曼峰的经验式归属。金属离子的半径，ｄ电子对卟啉环的排斥作用，金属卟啉骨架模式频率随孔穴大小，大环的平面性和π－π相互作用而相应变化的特性，都可用来解释不同金属离子配合物的结构灵敏特征峰为何存在着差异。     

原子氧在Ru低指数面及(110),(111)台阶面上的吸附

利用原子与表面簇合物相互作用的5参数Morse势方法(简称5-MP)系统地研究了O-Ru低指数面及Ru(1120),(1121)台阶面体系,获得了吸附几何、结合能、振动频率等临界点特性,所得相关数据与实验结果非常吻合.并且通过理论计算及原子吸附态振动指纹的遗传、遗变特性预言了氧原子在Ru(1121)台阶面的吸附.本文认为氧原子在HCP晶格的金属表面上的吸附倾向于三重位.     

聚L－谷氨酸－炔诺酮肟酯复合体的制备

合成了聚Ｌ－谷氨酸－炔诺酮肟酯的复合体，炔诺酮的接入量为２２．８％．体外释放时间约１５大。     

Novel polysiloxane formation process from dimethyldiethoxysilane in the presence of oxalic acid

Polysiloxane formation in dimethyldiethoxysilane (DMDES)-ethyl alcohol (EtOH(D))-oxalic acid (OA) (DMDES:EtOH(D):OA=1:2:0.5) and DMDES-dimethylsulfoxide (DMSO)-OA (DMDES:DMSO:OA=1:2:0.5) systems was investigated by gas chromatography-mass spectrometry and ²⁹Si-nuclear magnetic resonance. While the DMDES-EtOH(D)-OA system was homogeneous, the DMDES-DMSO-OA system consisted of two immiscible phases. In both systems, ethoxy-terminated linear oligomers ((EtO)Me₂SiO(Me₂SiO)_nSiMe₂(OEt); n=0–4, Et = C₂H₅, Me = CH₃) and cyclic tetramer ((Me₂SiO)₄) were identified. The reaction mechanism for polysiloxane formation is discussed.     

Potential response in the uncatalyzed bromate oscillatory system

The potential response of the platinum indicator electrode in the uncatalyzed bromate oscillator (UBO) with three different substrates, namely gallic acid (GA), pyrogallol (PG) and veratraldehyde (VA) has been analyzed. The large amplitude oscillations obtained with a Pt electrode are due to the sequential response of the indicator electrode to the varying concentration ratios of the redox couples present in the reaction mixture.     

The Synthesis and Structure of Silica-Sodalite from Nonaqueous Systems

A silica polymorph, silica-sodalite was synthesized from a nonaqueous system NaOH-SiO2-C2H4(OH)2 and its chemical compositionwas determined to be Si12 O24,2C2H4(OH)2 by the X-fluorescence,thermogravimetric and organic elemental analyses. The single crystal X-ray diffraction structure determination of the silica-sodaliteshowed that the silica-sodalite is cubic, spacing group I23 and unitcell parameter a= 8.8354A. The IF and solid state high resolution Siand 13 C NMR spectra of the silica-sodalite were measured and discussed .     

阿维菌素催化选择加氢合成伊维菌素研究

用RhCl3·3H2O和TPPDS间-(二磺化三苯基膦二钠盐),在水-有机两相催化体系中对阿维菌素选择加氢制备伊维菌素的研究,考察了反应温度(60～90℃)、氢气压力(1.0～4.0MPa)、配体浓度(2.2×10-3～5.2×10-3mol/L)、三乙胺浓度(0～8.4×10-4mol/L)、不同阳离子表面活性剂(TBAC:十四烷基二甲基苄基氯化铵;CPB:溴代十六烷基吡啶;CTAB:十六烷基三甲基溴化铵;TBAI:四丁基碘化铵)及反应时间对加氢反应活性和选择性的影响,其结果表明,在该两相体系中阿维菌素进行选择加氢是可行的,阳离子表面活性剂加入加快了反应速度,提高了反应的转化率和选择性.     

主成份分析-偏最小二乘法分光光度法同时测定钴、镍、铜、锌四组份体系

用 PCA 及 PLS 分步处理分光光度数据,有效降低了计算的维数。以该法对不同酸度体系的5-Br-PADAP-钴、镍、铜、锌分光光度数据进行了处理,定量分析结果良好。     

Pervaporative transport modelling in a ternary system: ethyltertiarybutylether/ethanol/polyurethaneimide

The study deals with the analysis of diffusion and mass transfer modelling during pervaporation in a true ternary system involving a polar liquid mixture (ETBE/EtOH) and a polar block copolymer (polyurethaneimide or PUI). A survey of methods of pervaporative transfer modelling in ternary systems is first developed. From differential permeation experiments carried out with both pure liquids, it appears that both permeants obey a Fickian law. Moreover, the diffusional behaviour is consistent with Long's model, which has thus been assumed for the related ternary system. An extension of the Brun's model is then derived, which takes into account the diffusion coupling as well the significant deviation from sorption ideality. From a practical point of view, the calculated values of fluxes show generally good agreement with the experimental results, although a small deviation occurs for mixtures of low ethanol content. Diffusion coefficients of both pure solvents corresponding to transient or steady state are compared. A very good agreement is found for the aprotic permeant (ETBE). whereas the diffusion coefficient of ethanol in transient state is only the quarter of the value corresponding to steady state. The results are discussed in comparison with related investigations in the literature, involving specific liquid-polymer interactions.