非靶标代谢组研究温度对黄曲霉菌代谢的影响

采用基于超高效液相色谱-高分辨质谱联用的非靶标代谢组学方法来研究温度对黄曲霉菌生理代谢的影响,使用交互偏最小二乘判别分析(Ortho PLS-DA)等化学计量学方法对代谢组数据进行多元统计分析,使用二级质谱信息和谱库检索定性黄曲霉菌代谢特征信息。使用内标结合混合质控样品的方法对非靶标代谢组方法进行质量控制。将该方法应用于研究温度对黄曲霉菌代谢组的影响,发现不同温度下有3 593个(T检验p0.01)差异表达代谢特征,筛选出20个候选差异代谢物。研究结果表明,温度显著影响三羧酸循环、脂肪酸、苯丙氨酸、色氨酸、络氨酸等生物合成路径,并调控黄曲霉毒素、黄匹阿尼酸、曲酸等次生代谢物生物合成路径酶活性。研究发现曲酸和黄曲霉毒素前体化合物与黄曲霉毒素的累积变化规律相似,可作为候选靶标进行验证。该研究为开展我国黄曲霉毒素风险评估和分子预警研究提供了新的路径和方法。     

DFT Study on the Effect of Hydrogen-bond Formation on the Adsorption of Aminotriazines on Graphene

DFT calculations have been performed to explore the aminotriazine adsorption on graphene surfaces.Relative energies,equilibrium geometries and electronic structures of monomer and dimer of aminotriazine molecules adsorbed at the surface were investigated and analyzed in details.It was found that the hydrogen atoms in the NH2 group of aminotriazine molecules are directed toward the graphene surface,and the adsorption energy increases as the NH2 group is added.The adsorbed aminotriazine molecules facilely form a dimer through the hydrogen bonding interactions,and the two aromatic rings of optimized structure of 2-amino-1,3,5-triazine(B) dimmer(denoted by B2) and melamine(D) dimmer(denoted by D2) are parallel to the graphene sheet.The large deviation of the averaged adsorption energy of B2 and D2 compared to monor adsorption may reflect the increase of π-π repulsion and the effect of hydrogen bond formation.The electronic structure analyses reveal that the formation of hydrogen bonds in melamine dimer has great influence on the adsorption mode at the graphene surface.     

镁电沉积研究评述

Mg离子二次电池是有望用于电动汽车的“绿色”蓄电池，它比Li离子二次电池低价、较高的安全性和环境友好及可大电流、大容量放电。本文对迄今为止关于镁的电沉积及镁离子二次电池的电解质溶液的研究进行综述；并对今后的研究提出了设想。     

Studies on Mechanism of Grafting of Polystyrene on Elastomer Backbone

The mechanism of grafting of polystyrene on a polybutadiene (PB) backbone during the preparation of impact-resistant polystyrene was studied by withdrawing samples during propolym-erization from beginning of the reaction to about 25% conversion. Good separation of the “elastomer and graft” fraction of the polymer from the free polystyrene part could be achieved by using 0.24 volume fraction of methanol in (MEK + benzene) + methanol solvent-nonsolvent. IR analysis of the grafted fraction showed that the microstructure of the elastomer remained unaltered. The unsaturation of the samples studied through the bromine number as well as by the perbenzoic acid number was also found to remain unchanged. Formation of free polystyrene started with the onset of polymerization and was faster. During prepolymerization, 80% of styrene converted constantly to form free polystyrene and 20% went into the grafted polymer. The results indicate that grafting is initiated through proton abstraction at the α-carbon of butadiene, most probably by initiator radicals. The grafted polystyrene chains possibly are shorter than free polystyrene chains.     

微量杂质对苯并三氧化呋咱(BTF)感度影响研究

苯并三氧化呋咱(BTF)是一种由三叠氮三硝基苯(TATNB)经脱氮反应制得的零氧无氢炸药,90℃～120℃温度范围内动力学参数计算外推得到其贮存寿命大约是太安的1．5倍,桥丝感度与太安相当,需要的能量较小,并使发火的电压降低,其起爆性能、输出能量、机械感度、热安定性均     

Effect of bile salts on adsorption of cholesterol on silica adsorbent

The adsorption of cholesterol and several bile salts on the surface of modified hydrophobic silica adsorbent from individual and mixed solutions is studied at constant solution pH as a function of the concentration of bile salts. It is shown that, despite the solubilization of cholesterol by bile salts, cholesterol is adsorbed on the adsorbent as an individual compound, i.e. not as a complex with bile salts. The stronger the cholesterol is bound with bile salts, the smaller the value of adsorption. For the quantitative interpretation of adsorption data, a nonelectrostatic model of complexation on the surface is used.     

溴代作用对竹红菌素分子性质影响的理论研究

用AM1方法对红菌素（包插甲素和乙素）与它们的溴代物进行了量子化学对比计算,得到了生成热,前线轨道能级及偶极矩等,讨论了溴代作用对竹红菌素分子性质的影响。     

Effect of temperature on the conformation of dibenzotropone adsorbed on montmorillonites

The nature of the adsorption complex formed between dibenzotropone (DBT) and montmorillonite at elevated temperatures is strongly dependent on the interlayer cations. This was shown by electronic and IR spectra, by X-ray diffraction, and by study of the effects of gradual heating of the samples on these analyses. All samples exhibited significant red shifts of the electronic spectra of DBT into the visible range. These red shifts are attributed to two factors, both contributing to the enhancement of the tropylium planar character of DBT: hydrogen-bonding of acidic interlayer water to the carbonyl group, imparting positive charge to the tropone ring; and π interactions between the aromatic moiety and the oxygen planes. The position of the maximum was temperature-dependent for Cu-, Ni-, Al- and Fe-montmorillonites, for which heating (100°) under vacuum increased the red shift. The organic molecule assumes a planar conformation and is oriented parallel to the clay layers. IR spectra confirming this conformational orientation of DBT are discussed. The basal spacings of the DBT montmorillonite associations depend on the number of water and DBT sheets present in the interlayers. Layers with one or two sheets of DBT and with up to two sheets of water could be distinguished, leading to a maximum spacing of 20.4 Å.     

喹啉氧基酞菁金属配合物光敏化氧化色氨酸能力的研究

酞菁金属配合物是光动力治疗的新一代光敏剂,其治疗作用的机理以及引起的生物效应一直是人们研究的热点.本文选用色氨酸作为与喹啉氧基酞菁金属配合物作用的靶分子,讨论了配合物的组成结构与其光敏化氧化色氨酸能力的相关性.结果表明,酞菁环内中心金属离子和环周边取代基的组成结构以及取代位置与数目都影响其光敏化氧化色氨酸能力,中心金属离子为闭壳层电子结构、取代基位于α位以及提高取代基数目均有利于提高光敏化氧化活性,同时显示,取代基的组成结构对靶分子有一定选择性,研究结果可为研发该类光敏剂提供依据.     

多壁碳纳米管对PS分子量影响的研究

由于碳纳米管（CNT）具有优异的力学、电学、光学等性能，近年来，聚合物／碳纳米管（polymer／CNT）复合材料的研究已经成为研究者关注的热点。相关的研究主要集中在：一是将CNT作为填充材料制各复合材料，使复合材料的力学、电学等性能得到提高。二是将CNT作为主体，用聚合物对CNT进行修饰，使CNT在有机溶剂中能够获得良好的溶解度。而对于在聚合反应中，CNT的加入对聚合物分子量影响的研究，相关的报道较少。本文利用悬浮聚合法制备了聚苯乙烯／多壁碳纳米管（PS／MWNT）复合材料，采用透射电镜（TEM）和凝胶渗透色谱（GPC）对其进行了分析，详细研究了MWNT对于PS分子量的影响。     

Pt在SAPO-11分子筛上的分散性研究

采用H2-TPR、NH3-TPD、H2脉冲化学吸附和H2-O2化学滴定等方法对Pt/SAPO-11催化剂上金属分散进行了表征,并与该催化剂制备因子及其正构烷烃骨架异构化反应性能进行关联。实验表明,以与NH3配位的阳离子形式制备的催化剂,Pt的分散效果最好;用低浓度浸渍液、多次浸渍的方式制备的催化剂,Pt的分散度高;Mn2+、Sm3+、Zn2+等作助剂和Pd-Pt复合浸渍可提高Pt的分散度。调整分子筛的酸量使之与金属含量达到平衡时,催化剂活性和选择性最佳。     

Investigation on the preconcentration of trace elements on polyacrylonitrile

Summary Trace amounts of Co, Ni, and Mn have been enriched from aqueous solutions by retention of their ions on polyacrylonitrile (PAN). The recovery has been determined as a function of the amount of PAN, pH, the concentration of eluent (HCl) and the volume of sample solution. The elements were removed with 100% efficiency by means of conc. HCl. Recoveries were up to 95% depending on the elements. The resin has been used in combination with atomic absorption spectrophotometry for the determination.     

磷素营养对植物抗旱性的影响

综述了近年来磷素营养与植物抗旱性关系的研究进展，指出磷素营养主要通过水分调节、渗透调节、光合调节和根冠生长等一系列生理生长机制来增强植物的代谢活性，提高植物抗旱性，植物对磷的利用效率与抗旱性也有着密切的关系。     

分子筛对葡萄糖淀粉酶的吸附性能研究

测定了黑曲霉葡萄糖淀粉酶(E.C.3.2.1.3)在三种改性的、具有中孔和大孔的分子筛上的吸附等温线并将吸附量和吸附等温线的形状与分子筛的等电点、孔容、孔径及酸性相关联。讨论了孔结构和不同酶吸附量对分子筛固定化葡萄糖淀粉酶活力的影响。发现葡萄糖淀粉酶在再造孔分子筛上的单层饱和吸附量与再造孔的方法密切有关,三种不同再造孔方法制得的分子筛具有不同的骨架Si/Al比、不同的孔分布和比表面积。不同的Si/Al比导致不同的酸性质和等电点。酶吸附量与载体的表面酸性、等电点以及吸附时溶液的pH有关。分子筛对酶的吸附以静电作用为主。其次,当中孔孔径和孔容越大时,单层饱和吸附量亦越大。随着分子筛对葡萄糖淀粉酶的吸附量增加,固定化酶的活力增大,但固定化酶的比活力随吸附量的增加、中孔孔容和孔径的减小而下降。     

Effect of crystallinity on radiation-induced graft copolymerization on cellulose

With vinyl monomers, viz., styrene, butyl methacrylate, dimethylaminoethyl methacrylate, and ethyl acrylate, it was noted that higher per cent grafting was obtained with “recrystallized” cellulose than with “amorphous” cellulose. The possibility of the production of a porous structure in cellulose as a result of γ-irradiation followed by the dissolution of the reactive regions is suggested. DTA and DTG data of irradiated cellulose triacetate (CTA) reveal lowering of the melting point on irradiation, indicating a decrease in crystallinity. Decrease in density of cellulose on irradiation by γ-rays also indicates loosening of the structure of cellulose. It is postulated that grafting occurs in those regions of cellulose which were crystalline before irradiation, as well as in less crystallinie regions.     

疏水界面上标准蛋白质吸附等温线的研究

测定了几种具有代表性的标准蛋白质在疏水色谱填料上的吸附等温线.除溶菌酶和牛血清白蛋白的吸附近似呈线性外,细胞色素-c、肌红蛋白、胰岛素、α-淀粉酶和卵清蛋白均呈凸型吸附.用Langmuir、计量置换吸附模型(SDM-A)、BET和Jovanovic吸附模型对这些蛋白的吸附等温线拟合后发现,SDM-A关系式能够良好描述这7种蛋白的吸附,Langmuir关系仅能较好地描述后5种蛋白质的吸附.而Jovanovic和BET关系式对上述两类蛋白质吸附的描述欠妥.实验发现对于不同盐浓度条件下卵清蛋白的吸附,用SDM-A和Langmuir公式拟合所得的参数与盐浓度之间呈现出一定的规律性.     

钼酸盐对卷烟燃烧氧化反应的催化作用

用自吸烟机、气相色谱，高效液相色谱和电子自旋波谱分别检测钼酸盐处理的卷烟和对照卷烟的燃烧速度，烟气焦油量，焦油中BaP和自由基的浓度，用差热分析和热失重分析探讨反应机理，结果表明，钼酸盐添加剂对降低卷烟燃烧反应的活化能，提高卷烟的燃烧速度，降低烟气焦油量，焦油中BaP和自由基有较高的活性。     

Effects of nanostructure on catalytic degradation of ethanol on SrCO3 catalysts

Degradation of ethanol over SrCO3 nanowires and nanoparticles was used as a model reaction to investigate the effect of nanostructure on chemical property. Differences in catalytic degradation activity with nanostructure are evaluated. The results indicated that catalytic activity of SrCO3 particles increases with decreasing of particle size due to high surface area. But this conclusion cannot be applicable to evaluating SrCO3 nanowires and nanoparticles. SrCO3 nanowires have lower ignition temperatures and wider working temperature ranges than SrCO3 nanoparticles, though nanowires had lower surface areas. Besides, ethanol degraded over nanowires in three ways, and the dominating reaction changes with reaction temperature. Consequently, the main degradation products of nanowires differed with temperature. But for nanoparticles, acetaldehyde is the only main product. Since transmission electron microscopy, X-ray diffraction, and bond equilibrium theory analysis demonstrated that nanowires and nanoparticles had similar crystal structure, surface area, and grain size, the differences in catalytic degradation activity between SrCO3 nanowires and nanoparticles can be attributed to different distributions of active sites, as proven by CO2 and ethanol temperature programmed desorption.     

温度对流动注射分析中溶液分散影响的研究

本文从理论和实验两方面进行了温度对流动注射分析中溶液分散影响的研究。结果表明,随着溫度升高,峰高值增大,半峰宽减小,保留值延长,峰面积则基本不变。增大进样体积和流速能够减小温度对峰高、半峰宽和保留时间的影响程度。     

苯硫酚各种形态在金上的拉曼光谱研究

用Gaussian 98程序在B3LYP/6-311＋G**(C, H, S)水平上计算得到苯硫酚(TP)的一套校正因子, 对苯硫酚各频率进行了势能分布(PEDs)分析, 并对各振动模式进行了详细的指认. 同时, 在B3LYP/6-311＋G**(C, H, S)/LANL2DZ(Au)水平上优化得到苯硫酚的各种形态与金结合, 即C₆H₅SH-Au, C₆H₅SAu, C₆H₅S^－-Au的平衡构型, 且在此基础上得到了C₆H₅SH-Au, C₆H₅SAu, C₆H₅S^－-Au三种形态的计算拉曼谱图. 其中苯硫酚金盐(C₆H₅SAu)的拉曼谱图与实验得到的苯硫酚在金溶胶中的谱图是一致的, 由此很好地证明了TP与金形成苯硫酚金盐.