Synthesis and evaluation of novel aza-caged Garcinia xanthones

Inspired by the therapeutic potential of the simplified caged xanthones, we have developed a chemical strategy for synthesizing novel aza-caged Garcinia analogues through a regioselective Claisen/Diels-Alder cascade reaction. The origin of regioselectivity has been explained using the DFT method. We have further evaluated the cell proliferation and IKKβ inhibitory activities of these compounds and studied their binding mode with IKKβ by molecular docking. The results suggested that the aza-caged scaffold provides a suitable modification site and the introduction of a hydrophobic moiety leads to improvement in the cytotoxicity and IKKβ inhibitory activity. The aza-caged compound 6c exhibited an IC(50) value of 2.68, 2.10, 8.02 μM against the HepG2, A549 cells and IKKβ, respectively. Mechanism studies with 6c showed that the aza-caged compounds induce apoptosis and cell cycle S phase arrest in A549 cells.     

Electrooxidation of formic acid catalyzed by Pd Nanoparticles supported on multi-walled carbon nanotubes with sodium oxalate

This paper repots a highly catalytic palladium nanoparticle catalyst dispersed on the purified multi-walled carbon nanotubes (P-MWCNTs) for the electrooxidation of formic acid, in which sodium oxalate is employed as both a dispersant and a coordination agent. The nanostructured catalysts have been characterized by X-ray diffraction technique and transmission electron microscopy. It is found that the as-prepared face-centered cubic crystal Pd nanoparticles are uniformly dispersed on the surface of MWCNTs with an average particle size of 5.6 nm. Fourier transform infrared spectroscopy and thermogravimetric analysis revel that sodium oxalate is a tractable ligand with the aid of a suitable solution. Cyclic voltammetry and chronoamperometry tests demonstrate that the obtained Pd/P-MWCNT catalyst from typical experiment has better catalytic activity and stability for formic acid electrooxidation than acid-oxidation treatment MWCNT (AO-MWCNT)-supported Pd catalyst from the control experiment. Therefore, the as-prepared Pd/P-MWCNTs would be a potential candidate as an anode electrocatalyst in direct formic acid fuel cells.     

基于色氨酸本征荧光测量的生物气溶胶检测技术研究

生物气溶胶与环境质量和人类健康密切相关。基于光学测量的气溶胶检测技术具有快速、无损和灵敏的优点,是目前的研究主流。而对检测系统的标定技术及其评价方法尚无国家标准可依。基于本征荧光测量技术,研制完成了一套针对包括病毒气溶胶在内的生物气溶胶检测装置。并在此基础上,以色氨酸气溶胶作为被检物,提出了一种生物气溶胶检测与标定方法。实验结果表明,研制的检测装置对色氨酸气溶胶具良好的线性响应特性,线性相关系数R2≥0.99,灵敏度达到4000L-1。证明了通过测量气溶胶中色氨酸含量检测生物气溶胶技术的可行性与可靠性。还探讨了利用多通道本征荧光检测技术实现对生物粒子种类进行预判别的可行性。     

非线性互补问题解的存在性检验

在数学规划研究领域中这是一个受到广泛关注的问题,并提出多种求解的迭代算法,但是几乎没有算法可以在计算数值解的同时自动给出解的误差界,Alefeld、Chen和Potra在[1],[2]中讨论了求解线性与非线性互补问题的可靠性算法,该算法是将非线性互补问题归结为：等价的非线性方程（经常被称为Pang方程[7]）     

求解互补问题的Newton方法的半局部收敛性

A semilocal convergence theorem is given for Newton method solving complementarity problems, which is identical in form to the standard Kantorovich theorem. All the convergence condition can be verified computationally.     

MHD数值模拟中清除伪磁场散度方法

针对全MHD (Magnetohydrodynamics)数值模拟中存在伪磁场散度的问题,发展了如下计算方法:基本格式基于八波对称形式方程组,补充相关源项以保持方程组守恒性,并采用投影方法辅助清除伪散度.投影方法中,基于有限体积方法求解三维Poisson方程.算例显示,对于光滑解析磁场,伪磁场散度得到有效清除;对于带激波高超声速MHD流动,全局投影下自由来流区域误差增大.提出一种局部投影方法,在高磁场散度区域进行投影.结果表明,最终流场收敛稳定,高磁场散度得到有效清除,而低散度区域散度不受影响.     

解一类线性互补问题的区间方法

1引言线性互补问题简记为LCP(M,q)是指对给定的n×n阶实方阵M和N维实向量q,求满足下列条件的实向量x：x≥0,Mx q≥0,(1．1) x~T(Mx q)=0．它在工程物理、管理学、经济学、约束最优化等领域有着广泛的应用背景．备受人们关注     

The Rich Tautomeric Behavior of Campestarenes

Campestarenes are a new family of Schiff‐base macrocycles that form selectively in a one‐step synthesis. These macrocycles with five‐fold symmetry show solvent‐dependent tautomerization and dimerization or aggregation. In this paper, we have prepared new soluble campestarenes that do not aggregate. The initial single‐crystal X‐ray diffraction study of a campestarene reveals that these macrocycles are nearly flat. The tautomeric behavior of the campestarenes has been extensively studied by variable‐temperature, multinuclear NMR spectroscopy, UV/Vis spectroscopy, and IR spectroscopy. In polar solvents, such as DMF, the molecules exist predominantly in their keto‐enamine form, but the enol‐imine tautomer is dominant in non‐polar solvents. A detailed computational study of the tautomeric forms of campestarenes provides a theoretical basis for their behavior and corroborates the experimental data. The results of this study give the first comprehensive understanding of the electronic and spectroscopic properties of these pentagonal macrocycles.     

时空分辨透射光栅谱仪及其应用

本文介绍了时间分辨透射光栅谱仪和空间分辨透射光栅谱仪的结构、原理和实验技术。给出了利用这两种谱仪在惯性约束聚变实验研究中获得的典型结果。     

SOME COMBINATORIAL PROBLEMS ON ORDERED TREES

Some formulas are established to calculate the number of leaves on all structurallydifferent ordered trees with n nodes,and the total leaf path length and the total node pathlength for those trees.Certainly,respective average numbers are obtained(the average pathlength may be considered as the average height of random ordered trees with n nodes),Actually,this paper presents a general method dealing with some classes of combinaorialproblems on ordered trees.