固定相优化液相色谱法对候选新药雷公藤衍生物进行有关物质检查

采用固定相优化液相色谱法(POPLC)建立了候选新药雷公藤衍生物(T8)中有关物质的检查方法.分别采用5种不同类型的固定相色谱短柱对含有T8和有关物质的混合溶液进行实验,流动相为乙腈-水(35:65,V/V),流速为0.5 mL/min,柱温为30 ℃,检测波长为219 nm,获得相应各柱死时间、各组分保留时间和理论板...     

Preparation and Crystal Structures of Two Polymorphic Forms of Bupropion Hydrobromide

Two polymorphic forms (forms I and IV) of antidepressant bupropion hydrobro- mides were prepared and characterized by powder X-ray single-crystal diffractometer. Lots of commercial substances may consist of form I. Form I crystallizes in the triclinic system, space group P1 with Z = 2, a = 7.6943(8), b = 7.9347(9), c = 13.8558(15) , α = 85.971(3), β = 85.619(2), γ = 65.974(3)°, V = 769.66(14) 3, Dc = 1.384 g/cm3, formula C13H19ClNOBr, F(000) = 328, μ = 2.83 mm-1, the final R = 0.0579 and wR = 0.1282 for 1756 observed reflections with I > 2σ(I). Another polymorphic form, Ⅳ, belongs to the orthorhombic system, space group Pbca with a = 8.6365(3), b = 12.4167(4), c = 27.7299(9) , Z = 8, V = 2973.67(17) 3, Dc = 1.432 g/cm3, formula C13H19ClNOBr, F(000) = 1312, μ = 2.93 mm-1, the final R = 0.044 and wR = 0.1093 for 2018 observed reflections with I > 2σ(I). In the crystal structure of the two polymorphic forms, expected proton transfer from HBr to amino group of bupropion molecule occurs and intramolecular and intermolecular hydrogen bonds N–H···r are formed. These interactions result in hydrogen-bond dimers in these two forms. The bupropion molecule adopts different conformations in the two investigated solid state modifications.     

高阶抛物不等式组的Liouville型定理及其应用

In this paper, we establish a Liouville-type theorem for a system of higher-order parabolic inequalities by using the method of test functions and an integral estimate. As an application, we observe the Fujita blow-up phenomena for the corresponding parabolic system, which in particular fills up the gap in the recent result of Pang et. al. （Existence and nonexistence of global solutions for a higher-order semilinear parabolic system, Indiana Univ. Math. J., 55（2006）, 1113-1134）. Moreover, the importance of this observation is that we do not impose any regularity assumption on the initial data.     

Large Solutions to Complex Monge-Amp`ere Equations:Existence, Uniqueness and Asymptotics

The authors consider the complex Monge-Ampère equation det( u_i[`(j)] )\left( {u_{i\bar j} } \right) = ψ(z, u, ∇ u) in bounded strictly pseudoconvex domains Ω, subject to the singular boundary condition u = ∞ on ∂Ω. Under suitable conditions on ψ, the existence, uniqueness and the exact asymptotic behavior of solutions to boundary blow-up problems for the complex Monge-Ampère equations are established.     

磁性高强度聚丙烯酰胺/Fe3O4纳米复合水凝胶

以辐射过氧化的表面活性剂胶束为引发中心和交联中心, 制得具有优异机械性能的聚丙烯酰胺(PAAm)水凝胶, 并通过原位化学共沉淀法向其中引入Fe₃O₄粒子, 得到了磁性复合水凝胶. 扫描电子显微镜(SEM)表征发现磁性粒子在凝胶中分布均匀, 其粒径约为30 nm. X射线衍射(XRD)表征证实所引入的纳米粒子为尖晶石型Fe₃O₄. 磁性能测试表明, PAAm/ Fe₃O₄复合水凝胶具有超顺磁性特征. 该复合凝胶具有较优异的机械性能, 其断裂伸长率可以达到1200%, 拉伸强度最大可达0.10 MPa. 另外, 该复合凝胶表现出良好的形变回复特性.     

纳米晶核的尺寸与表面对生长与组装过程影响的研究进展

晶核作为晶体生长过程中新相形成的开始,理解它们的性质和行为特点对纳米材料的控制合成有重要指导意义,尤其对形貌和尺寸的调控。可控合成的超小尺寸纳米晶(<5 nm)为研究晶核的性质提供了一个理想模型。本文基于纳米晶核在纳米材料控制合成中的研究进展,论述了晶核的尺寸与表面结构对纳米材料生长与组装模式的影响,尤其是基于纳米晶核预组装途径的晶体生长模式。     

用不对称二羟基化反应合成(S)-美托洛尔

在K2CO3存在下,4-(2-甲氧乙基)苯酚与烯丙基溴反应制得烯丙基[4-(2-甲氧乙基)苯基]醚(2);以廉价易得的双金鸡纳碱衍生物1,4-双(9-O-奎尼定)-2,3-二氮杂萘为手性配体催化2的不对称二羟基化反应制得(S)-3-[4-(2-甲氧乙基)苯氧基]-1,2-丙二醇(3,86%ee); 3经"一锅法"转化为...     

手性咪唑酯类离子液体的合成及其物理性能

以咪唑,溴代烷烃及(-)-薄荷醇为原料合成了12个手性咪唑酯类离子液体,其结构经NMR和IR表征.物理性能研究结果表明,该类离子液体具有较好的热稳定性,且比旋光度存在一定的改变规律.     

Aptamer-based competitive electrochemical assay of small biomolecules

A convenient aptamer-based competitive electrochemical biosensor for a small biomolecule,adenosine,was described. The sensing surface was fabricated by self-assembly of an aptamer/mercaptohexanol monolayer on a gold disk electrode. The principle of this aptasensor is based on the competition between an adenosine target molecule and a ferrocene-conjugated signaling DNA strand for the aptamer binding site on the sensing surface. Due to the competitive nature of this assay,the electrochemical responses of the ...