咪唑并[1,2-a]吡啶化合物的无溶剂合成及其抗氧化性能

无溶剂条件下,2-氨基吡啶、芳香醛和异氰基乙酸乙酯发生Groebke-Blackburn-Bienaymé三组分反应,高效合成了6个咪唑并[1,2-a]吡啶化合物,产率89%~97%,其结构经¹H NMR, ¹³C NMR和HR-MS（ESI）确证。并通过抑制HO·和还原型谷胱甘肽自由基(GS·)引发的DNA氧化反应体系,对化合物的抗氧化活性进行了检测。结果表明：在抑制HO·引发的DNA氧化反应体系中,6个化合物相对空白硫代巴比妥酸活性物质吸光度百分数（TBARS百分数）可达32.2%~72.1%;在抑制GS·引发的DNA氧化反应体系中,6个化合物的TBARS百分数可达34.8%~81.3%。     

超高效液相色谱-三重四极杆质谱法检测油脂和油炸食品中7种杂环胺类物质

建立了检测油脂及油炸食品中7种杂环胺类物质的超高效液相色谱-三重四极杆质谱（UPLC-MS/MS）的检测方法。以含1%（体积分数）氨水的乙腈溶液为提取液,采用乙腈饱和的正己烷脱脂,以PCX固相萃取柱为净化柱,10 mmol/L甲酸铵溶液（pH 6.8）和乙腈为流动相,采用Waters ACQUITY UPLC BEH C18反相色谱柱（50 mm×2.1 mm,1.7 μm）梯度洗脱,流速为0.3 mL/min,在正离子扫描、多反应监测模式下测定,内标法定量。结果表明,杂环胺类物质在各自范围内,线性关系良好,相关系数大于0.999;在3个加标水平下,杂环胺类物质在油脂和油炸食品中的平均回收率为64.31%~113.8%,相对标准偏差为0.18%~9.26%,检出限（S/N=3）和定量限（S/N=10）分别为0.01~0.14 ng/g和0.09~0.38 ng/g。该方法具有灵敏、准确等优点,适用于油脂和油炸食品中杂环胺的确证检测。     

Methyl β-(Benzotriazol-l-yl) vinyl Ketone: A New p-Acetylvinyl Cation Equivalent

A simple and efficient two-step approach to methyl β-(benzotriazol-1-yl)vinyl ketone 7 is described. The synthetic utility of compound 7 has been demonstrated by nucleophilic substitutions of the benzotriazolyl group with a range of nucleophiles. Thus, methyl β-(benzotriazol-1-yl)vinyl ketone provides a new β-acetylvinyl cation equivalent.     

Flame-retarded mechanism of SEBS/PPO composites modified with mica and resorcinol bis(diphenyl phosphate)

The flame retardancy of styrene-b-ethylene/butylene-b-styrene triblock polymer (SEBS)/poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) blends was greatly improved by the combined use of mica and resorcinol bis(diphenyl phosphate) (RDP). The limiting oxygen index (LOI), vertical burning and cone calorimeter test were performed to evaluate the flame-retarded effect. The composite of SEBS/PPO/maleic anhydride grafted SEBS (SEBS-g-MAH) with a mass ratio of 11/11/3 passed a V-0 rating in the UL94 test by the addition of 10–15 wt% mica and 15–10 wt% RDP with total amount of 25 wt%. The synergism was confirmed by the mathematical evaluation of the synergistic effect index (SE) in LOI, the residue, the peak heat release rate (PHRR) and the total heat evolved (THE) per mass loss (THE/ML). The flame-retarded mechanism of the composite was also proposed on the results of cone calorimeter test, TGA-FTIR, SEM micrographs and SEM/EDS analysis of the residues. It was found that the degradation rate of SEBS/PPO/SEBS-g-MAH matrix was slowed down, a more consolidated char layer with higher residue was promoted by the combination of RDP and mica. The flame-retardancy of RDP with mica in SEBS/PPO/SEBS-g-MAH matrix was synergistic through gas and condensed phase action.     

Temperature Dependence in the Synthesis of SBA-16-Type Mesoporous Silica with Pluronic F68 Block Copolymer

By adjusting the local effective surfactant packing parameter through synthesis temperature, highly ordered SBA-16-type mesoporous silica materials have been synthesized by templating with a nonionic triblock copolymer Pluronic F68 in strongly acidic conditions at temperature 30～40°C with the addition of K₂SO₄. The prepared SBA-16-type mesoporous silica materials having Im3m cubic mesostructure were proved by the well-defined x-ray diffraction patterns combined with transmission electron microscopy. Scanning electron microscopy indicated that a transformation from faced-sphere to faced-polyhedron shape morphologies could be induced with increasing of the synthesis temperature. The nitrogen adsorption–desorption analysis revealed that the mean pore size (5.50～6.13 nm) of the prepared materials increased with increasing synthesis temperature. However, when the synthesis temperature exceeded 46°C, only disordered mesoporous silca was obtained. Our synthesis strategies by adjusting the local effective surfactant packing parameter through synthesis condition, even in a narrow range, would be used not only to optimize the synthesis conditions of reported mesoporous silca, but also to fabricate new mesoporous silica materials with well-ordered channel and anticipated morphologies.     

富勒烯与β淀粉样肽低聚体结合的分子动力学模拟

本文通过分子动力学模拟研究富勒烯在Aβ42低聚体表面的结合过程.在结合过程中,C60在Aβ表面经历一系列尝试过程,最终找到某个稳定的结合位点.根据结合的残基不同,这些结合位点可以分为六类,其中核心疏水区域(CHC)位点(17LVFFA21)及Turn 27-31位点(27NKGAI31)具有最强的结合稳定性.二者的结合主要通过范德华作用稳定,而溶剂化效应则起相反作用.在这六类位点中的两个位点,观察到C60会对Aβ二级结构起破坏作用.其一位于核心疏水区域,C60有挤入多肽β片层中间的趋势;另外一位点位于N端,C60能够破坏外侧Aβ的3-5号残基的主链氢键,瓦解其末端的β片结构.这两个过程对理解富勒烯抑制Aβ聚集的微观机制提供了帮助.此外,在Turn 27-31位点以及Y10-H14位点,发现了富勒烯与Aβ纤维样聚集体结合的沟槽滚动机制,即富勒烯能够在淀粉样低聚体表面形成的特定沟槽内滚动.这一特征有助于预测富勒烯在其它淀粉样多肽表面的结合位点及结合行为.     

几种金属离子对胭脂红与牛血清白蛋白相互作用的影响——荧光光谱研究

利用荧光光谱法研究了不同温度(15、27、39℃)下食用合成色素胭脂红对牛血清白蛋白(BSA)的内源荧光猝灭特性,考察了Cu2+、Ni 2+、Pb2+等金属离子对二者相互作用的影响,并测定了不同温度下的猝灭常数KSV、结合常数KA和结合位点数n.结果表明,3种金属离子基本不影响胭脂红对BSA荧光猝灭机理,但Cu2+、Ni 2+、Pb2+离子都与BSA有一定的结合能力,可在不同程度上增强胭脂红与BSA的结合作用及其对BSA内源荧光的猝灭.     

Homologous and heterologous interactions between catalytic and regulatory subunits of Escherichia coli acetohydroxyacid synthaseⅠand Ⅲ

Homologous and heterologous interactions between acetohydroxyacid synthase (AHAS) I and Ⅲ from E. coli have been studied by surface plasmon resonance (SPR). The catalytic and regulatory subunits association for AHAS I (KD = 1.13 × 10-7 M) was stronger than that for AHAS Ⅲ (KD = 5.29 × 10-7 M). A strong heterologous association between regulatory and catalytic subunits and heterologous activation of catalytic subunits were observed. SPR results combined with enzyme kinetics indicate that the reconstituted he...     

柱坐标系z轴邻域内的连续方程

通过分析坐标系中z轴邻域内连续方程的推导，阐明了推导流体力学控制方程时常常被忽略而应注意的几个问题。     

Bi-Pb-Sr-Ca-Cu-O系反应过程研究

采用高温X射线和DTA技术研究了三步反应法合成Bi-Pb-Sr-Ca-Cu-O超导体的反应过程。实验结果表明样品在740℃能形成2212相,在825℃形成2223相.2212相在875℃左右异分熔化成2201相和液相,2223相在935℃左右同分熔化。2212相在晶化过程中容易形成强的c轴取向。 关键词：