Pharmacophore-based design,synthesis, and biological evaluation of novel 3-（（3,4-dichlorophenyl）（4-substituted benzyl）amino） propanamides as cholesteryl ester transfer protein （CETP） inhibitors

Cholesteryl ester transfer protein （CETP） is a plasma glycoprotein that plays an important role in decreasing high-density lipoprotein cholesterol （HDL-C） levels and increasing low-density lipoprotein cholesterol （LDL-C） levels. Inhibition of CETP may be a new therapy for treating atherosclerosis. Herein, we report the development of a ligand-based pharmacophore model and pharmacophore-based virtual screening of the ZINC/big-n-greasy database, leading to the identification of compound H-10 as a potential CETP inhibitor in vitro. Based on H-10, a series of 3-（（3,4-dichlorophenyl）（4-substituted benzyl）amino） propanamides were designed, synthesized, and evaluated against CETP. Compound 41 was found to have the best activity, resulting in 85.0% inhibition of CETP at l0 μmol/L.     

ClF3O和环氧丙烷反应的理论研究

应用密度泛函理论对 ClF3 O 和环氧丙烷的反应机理进行了研究。在 B3PW91/6-31++G(d ,p )水平上优化了各驻点(反应物、中间体、过渡态和产物)的几何构型,并计算了它们的振动频率和零点振动能。采用 CCSD(T)/6-31++G(d ,p )//B3PW91/6-3l++G(d ,p )单点能计算方法求得各物质的能量,并做零点能校正。计算结果表明,ClF3 O 与 C3 H 6 O 可经过不同的反应路径,引发 C3 H 5 O 自由基和 ClOF2自由基生成环氧丙醇和三氟化氯,其中,位于 ClF3 O 周向位置的 F 原子与 C3 H 6 O 的 C(7)上与 CH 3异侧的 H(9)原子结合的活化能最低,仅15.63 kJ/mo1;ClF3 O 与 C3 H 6 O 反应生成的 C3 H 5 O 自由基和 ClOF2自由基继续反应,经过不同反应路径生成 C3 H 4 O、ClOF 和 HF,其中,ClOF2中的 F 原子和 C3 H 5 O 中的 H(2)或 H(4)原子结合是无能垒的过程。整个反应的主要路径为 C3 H 6 O+ClF3→O→TS12 P4(C3 H 5 O+HF+ClOF2→) P12(CH 2 CHCHO+2 HF+ClOF)。     

N80油套管钢应力状态下的CO2腐蚀行为研究

利用交流阻抗技术研究了拉伸、压缩和弯曲三种应力状态下N80油套管钢在饱和CO₂地层水中的腐蚀过程. 结果表明, 三种状态下的阳极电化学阻抗谱均出现了高频容抗弧、中低频感抗弧和低频容抗弧三个时间常数, 其中高频容抗弧与双电层电容和传递电阻有关, 感抗弧对应膜的活性溶解, 低频容抗弧与试样表面膜的生成有关. 随着三种状态下应变的增加, 感抗弧逐渐扩大, 而低频容抗弧则逐渐缩小, 表明应力状态下N80钢的CO₂腐蚀会加剧. 三种状态下的阴极阻抗谱高频均由容抗弧组成, 中低频由Warburg阻抗和容抗弧共同组成, 三种状态下随着应变程度的增加, Warburg阻抗增加, 反应电阻减小, 双电层电容减小, 说明应力会加速阴极反应过程的进行, 从而增加N80钢的CO₂腐蚀速率.     

配合物[Co(qina)2(H2O)2]•2DMSO的晶体结构及其与DNA作用研究

合成了配合物[Co(qina)₂(H₂O)₂]•2DMSO单晶(qina为喹哪啶酸). 配合物属于单斜晶系, P2(1)/n空间群, 其分子结构为规则的八面体构型, qina以氮原子和羧酸根氧原子与Co^2＋离子配位, 两个水分子为轴向配位. 配合物之间富有配位水分子分别与DMSO的氧原子、qina中未与Co(II)配位的氧之间氢键作用. 配合物与鱼精DNA作用的紫外光谱和荧光光谱表明, 两者之间有一定的相互作用, 并可能以局部插入方式为主.     

基于石墨烯编码超构材料的太赫兹波束多功能动态调控

提出了一种基于石墨烯带的太赫兹波段的1 bit编码超构材料,可以实现太赫兹波束的数目、频率、幅度等参数多功能动态调控.该结构由金属薄膜、聚酰亚胺、硅、二氧化硅、石墨烯带组成.通过对石墨烯带施加两种不同的电压,可以实现一定频率范围内相位差接近180?的"0"和"1"数字编码单元,进而构成1 bit动态可控的编码超构材料.全波仿真结果表明,不同序列的编码超构材料能够实现波束数目从单波束、双波束、多波束到宽波束的调控.相同序列的编码超构材料,通过施加石墨烯带的不同电压能够实现宽频段波束频率的偏移.对于000000或者111111周期序列的编码超构材料,通过施加石墨烯带的不同电压还能够实现波束幅度的调控.因此这种基于石墨烯带的编码超构材料为灵活调控太赫兹波提供了一种新的途径,将在雷达隐身、成像、宽带通信等方面具有重要的意义.     

Dynamic Response and Fracture Mechanism of a Novel Structural Radar Absorbing Material

A novel structural radar absorbing material （SRAM）, which gives the normal resin-base composites new function, is prepared. The dynamic compressive tests of SRAM are carried out in both in-plane and normal directions of composites by means of the split Hopkinson pressure bar （SHPB）. In the compressive test along in-plane direction, failure occurs at the interface between a fibre and the matrix. A fracture mode and mechanism was proposed to explain these results. The addition of absorbing particles results in the deterioration of the compressive properties. However, there is no obvious decrease on compressive strength of SRAM with the radar absorbing properties.     

甲酸铵催化转移氢化还原肽链中的芳香硝基——对氨基苯丙氨酸的间接引入

研究了用甲酸铵催化转移氢化法(AF-CTH)对不同类型肽中的芳香硝基的还原行为, 这些肽类化合物包括促黑激素(MSH: 四肽)、促黄体素释放激素(LHRH: 十肽)和强腓肽(十七肽)的类似物. 用HPLC对还原过程进行了跟踪监测, 结果显示, 除含对氯苯丙氨酸残基的LHRH类似物因发生脱氯副反应不适合用AF-CTH还原外, 其余序列还原过程中均无明显副反应发生, 硝基几乎定量地转化成为相应的氨基, 实现了对氨基苯丙氨酸向肽链的间接引入. 另外发现, 硝基还原所需的时间与肽链长度有关, 肽链越长, 还原所需时间越长, 但与其在序列中的位置关系不明显.     

Synchronization and coherence resonance in chaotic neural networks

Synchronization and coherence of chaotic Morris--Lecar (ML) neural networks have been investigated by numerical methods. The synchronization of the neurons can be enhanced by increasing the number of the shortcuts, even though all neurons are chaotic when uncoupled. Moreover, the coherence of the neurons exhibits a non-monotonic dependence on the density of shortcuts. There is an optimal number of shortcuts at which the neurons' motion is most ordered, i.e. the order parameter (the characteristic correlation time) that is introduced to measure the coherence of the neurons has a maximum. These phenomena imply that stochastic shortcuts can tame spatiotemporal chaos. The effects of the coupling strength have also been studied. The value of the optimal number of shortcuts goes down as the coupling strength increases.     

Enhanced Synchronization of Intercellular Calcium Oscillations by Noise Contaminated Signals

We consider the dynamics of locally coupled calcium oscillation systems, each cell is subjected to extracellular contaminated signal, which contains common sub-threshold signal and independent Gaussian noise. It is found that intermediate noise can enhance synchronized oscillations of calcium ions, where the frequency of noise-induced oscillations is matched with the one of sub-threshold external signal. We show that synchronization is enhanced as a result of the entrainment of external signal. Furthermore, the effect of coupling strength is considered. We find above-mentioned phenomenon exists only when coupling strength is very small. Our findings may exhibit that noise can enhance the detection of feeble external signal through the mechanism of synchronization of intercellular calcium ions.     

Enhanced mechanical behaviour of lead zirconate titanate piezoelectric composites incorporating zinc oxide nanowhiskers

This paper reports that the lead zirconate titanate （PZT） piezoelectric composites incorporating zinc oxide nanowhiskers （ZnOw） were prepared by the conventional solid state processing. The whisker-dispersed PZT composites （PZT/ZnOw） presented a significant enhancement in the mechanical properties such as Young＇s modulus, tensile strength and compressive strength. Especially, the compressive strength increased from 153 MPa for the PZT to 228 MPa for the PZT/ZnOw composites. The reinforcement mechanism in strength of the composites was discussed. The me- chanical quality factors of the PZT/ZnOw composites increased considerably, while the piezoelectric constants and electromechanical coupling coefficient decreased slightly. The composites with good electrical and excellent mechanical properties are promising for further applications.