Synthesis and antitumor activity of camptothecin- 4β-triazolopodophyllotoxin conjugates

Abstract

Two new compounds (9 and 10) having a camptothecin (CPT) analog conjugated to the 4β-azido-4-deoxypodophyllotixin analog by untilizing the copper-catalyzed azide-alkyne cycloadditon (CuAAC) reaction, and were evaluated for their cytotoxicity against a panel of five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7 and SW480) using the MTT (3-(4,5-dimethyl-thiahiazo-2-yl)-2,5-diphenyltetrazolium bromide) assay. Two novel conjugates shown weak cytotoxicity, compound 10 showed highly potent against HL-60 cell line tested, with IC₅₀ value 17.69?±?0.19?μM. This compound suggested its potential as anticancer agents for further development.

     

枪口火焰光电测量方法探讨

该文简述了常用枪口火焰测量的几种方法,对各方法存在的问题下作了系统分析,类比于枪口噪声的测量科学地提出了评价枪口火焰大小及强弱的评价指标,在此基础上提出了一种行之有效的光电测试方法,文中阐明了该方法的原理及系统组成,通过枪口火焰的实弹实验,证明了该方法的可行性。     

The v-v energy transfer of highly vibrationally excited states (II)

The vibrational energy transfer from highly vibrationally excited CO to H₂O molecules is studied by time-resolved Fourier transform infrared emission spectroscopy (TR FTIR). Following the 193 nm laser photolysis of CHBr₃ and O₂ the secondary reactions generate CO(v). The infrared emission of CO(v → v−1) is detected by TR FTIR. The excitation of H₂O molecules is not observed. By the method of the spectral simulation and the differential technique, 8 rate constants for CO(v)/H₂O system are obtained: (1.7 ±0.1), (3.4 ±0.2), (6.2 ±0.4), (8.0 ±1.0), (9.0 ±2.0), (12 ±3), (16 ±4) and (18 ±7) (10¹³cm³ · molecule^-1· s^-1). At least two reasons lead to the efficient energy transfer. One is the contributions of the rotational energy to the vibational energy defect and the other is the result of the complex collision. With the SSH andab initio calculations, the quenching mechanism of CO(v) by H₂O is suggested.     

白卡奴鸽动脉粥样硬化模型微量元素谱的计算机多元分析

用ＩＣＰ－ＡＥＳ测定了白卡奴鸽动脉粥样硬化模型和对照组的器官和组织中１９种元素含量，通过因子分析，取得一系列因子得分图，结果表明，动脉粥样硬化和对照组样品点分布在不同区域，且可分辨。     

Simulations of stochastic sensing of proteins

We have performed Langevin dynamics and Poisson-Nernst-Planck calculations to simulate detection of proteins by genetically engineered alpha-hemolysin channels. In the recent stochastic sensing experiments, one end of a flexible polymer chain is permanently anchored inside the protein channel at a specified location, and the other end undergoes complexation with an analyte. Our simulations, using coarse-grained modeling, reproduce all essential qualitative results of the electrophysiology measurements of stochastic sensing. In addition, the underlying macromolecular mechanisms behind stochastic sensing are revealed in vivid details. The entropic fluctuations of the conformations of the tethered polymer chain dictate crucially the unique signatures of the ionic current trace of the channel and provide design rules for successful stochastic sensing. The origin of strong fluctuations in the ionic current of the channel is found to arise from the obstruction of the entrance at the beta-barrel of the channel by the fluctuating segments of the tether. Silencing of the pore is due to the suppression of conformational fluctuations of the chain, and the permanent blockade of ionic current is due to the threading of the tether through the channel. The onset of silencing and permanent blockade of the channel current cannot necessarily be attributed to the capture of analytes. In order for detection events to be timed accurately, the length and anchoring location of the tether must be tuned appropriately.     

Experimental and modeling study on decomposition kinetics of methane hydrates in different media

The decomposition kinetic behaviors of methane hydrates formed in 5 cm3 porous wet activated carbon were studied experimentally in a closed system in the temperature range of 275.8-264.4 K. The decomposition rates of methane hydrates formed from 5 cm3 of pure free water and an aqueous solution of 650 g x m(-3) sodium dodecyl sulfate (SDS) were also measured for comparison. The decomposition rates of methane hydrates in seven different cases were compared. The results showed that the methane hydrates dissociate more rapidly in porous activated carbon than in free systems. A mathematical model was developed for describing the decomposition kinetic behavior of methane hydrates below ice point based on an ice-shielding mechanism in which a porous ice layer was assumed to be formed during the decomposition of hydrate, and the diffusion of methane molecules through it was assumed to be one of the control steps. The parameters of the model were determined by correlating the decomposition rate data, and the activation energies were further determined with respect to three different media. The model was found to well describe the decomposition kinetic behavior of methane hydrate in different media.     

冠心病微量元素谱的计算机模式识别

用计算机多元分析研究冠心病微量元素谱，识别冠心病患者与健康者；非线性映射法判别率男性８６．６％，女性９６．２％；ＳＩＭＣＡ差别法正确回判率男性８５．０％，女性８８．３％。     

Studies on the Phase Properties of Winsor Ⅰ-Ⅲ Type Microemulsions with Dielectric Relaxation Spectroscopy

The dielectric relaxation spectroscopy （DRS） of Winsor I -Ⅲ microemulsions for nonionic surfactant octyl polyglucoside CsG1.46/1-butanol/cyclohexanedwater system was studied. The experiment shows that the permittivity decreases with the increase in the frequency and clear dielectric relaxation phenomena were observed. Permittivity obviously decreases with the change of the microstructure of the microemulsion, W/O, B.C. and O/W can be distinguished by the permittivity.