The effect of the curing agent content on the curing and liquid‐crystalline phase of liquid‐crystalline epoxy resin

The effect of the curing agent content on the curing behavior and liquid‐crystalline (LC) phase of the liquid‐crystalline epoxy (LCE) resin 4,4′‐di(2,3‐epoxypropyloxy)phenyl benzoate was studied. Diaminodiphenylester (DDE) was used as a curing agent. The curing behavior was observed via differential scanning calorimetry, and the LC phase was investigated with a polarized optical microscopy. The LC phase in the LCE/DDE mixture with a high DDE content was developed during curing. The onset time was inversely proportional to the DDE content. The mesophase stability of LCE/DDE was enhanced by the addition of large amounts of DDE. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 374–379, 2001     

Synthesis and activity mechanism of some novel 2-substituted benzothiazoles as hGSTP1-1 enzyme inhibitors$

Abstract

Human GSTP1-1 is one of the most important proteins, which overexpresses in a large number of human tumours and is involved in the development of resistance to several anticancer drugs. So, it has become an important target in cancer treatment. In this study, 12 benzothiazole derivatives were synthesized and screened for their in vitro inhibitory activity for hGSTP1-1. Among these compounds, two of them (compounds #2 and #5) have been found to be the leads when compared with the reference drug etoposide. In order to analyse the structure–activity relationships (SARs) and to investigate the binding side interactions of the observed lead compounds, a HipHop pharmacophore model was generated and the molecular docking studies were performed by using CDocker method. In conclusion, it is observed that the lead compounds #2 and #5 possessed inhibitory activity on the hGSTP1-1 by binding to the H-site as a substrate in which the para position of the phenyl ring of the benzamide moiety on the benzothiazole ring is important. Substitution at this position with a hydrophobic group that reduces the electron density at the phenyl ring is required for the interaction with the H side active residue Tyr108.     

Design and synthesis of biotinylated dimethylation of alkannin oxime derivatives

DMAKO-05, a novel dimethylation of alkannin oxime derivative, exhibits remarkable anticancer activity as well as excellent cellular selectivity and thus has been considered as a promising antineoplastic agent for colorectal carcinoma and melanoma. However, its potent cytotoxicity is not closely associated with reactive oxygen species (ROS) and bioreductive alkylation. Its specific antitumor target(s) has still remained elusive. To recognize the molecular target(s) of DMAKO-05 and its analogs, four biotinylated DMAKO derivatives were designed and prepared. The biotin moiety was successfully introduced in the molecule through a modified Mitsunobu reaction, which kept its anticancer activity. Moreover, the cellbased investigation demonstrated that replacement of the linker C₄ chain with another alkyl chain (C₆ or C₈) gave rise to the enhancement of cytotoxicity. Among these biotinyl derivatives, both compound 16 and 8c exhibited more potent anticancer activity than DMAKO-05 against MCF-7 cells and were comparatively effective to alkannin toward HCT-15 cells. As expected, they might be thought as ideal chemical probes. Collectively, our present work could provide an available approach for the identification of the potential antineoplastic target(s) of DMAKO derivatives.     

酰胺型萃取剂N-503的合成

酰胺型萃取剂N-503[N,N-二-(1-甲基庚基)乙酰胺]可以用甲庚醇或2-氯代辛烷为原料来合成。它的重要中间体二-(1-甲基庚基)胺的制备方法有二:一是从甲庚醇制备的方法,将甲庚醇用阮来镍催化,常压氨解,得率95～99％左右;二是从2-氯代辛烷制备,此法需要高压设备,得率35％左右。第一个方法在扩大试验中,产率和产品质量都比较好,是一个较好的制备长碳链仲胺的方法。     

7-十二烯基-8-羟基喹啉的合成

7-十二烯基-8-羟基喹啉是一种新型螯合型萃取剂(Kelex 100的主要成份)。它是(1a)和(1b)异构体的混合物。本文报道了利用1-氯-1,1,3,3-四甲基丁烷与过量丁二烯-[1,3]的1,4加成反应合成重要中间体1-氯-5,5,7,7-四甲基辛烯-[2](3)的方法,此法具有室温、常压、产率高、设备简单、操作方便等优点。     

测接触角法确定偶联剂的最佳用量

偶联剂是一类能在无机填料和聚合物基材之间形成“分子桥”、改善两者之间相容性或提高两者之间相互作用能力的化合物。将经偶联剂改性的无机填料填充到聚合物中可以制得成本低、性能好的复合材料。由于偶联剂用量多少将对复合材料的性能产生较大影响,因此建立一种准确、简便地确定偶联剂最佳用量的方法有着十分重要的理论和实际应用意义。     

Synthesis of aromatic poly(thioether ketone)

Aromatic poly(thioether ketone)s were prepared by the direct polycondensation of aromatic dicarboxylic acids with aryl compounds containing ether or sulfide structures using phosphorus pentoxide/methanesulfonic acid (PPMA) as a condensing agent and solvent. Polycondensation proceeded smoothly and produced aromatic poly(thioether ketone)s with inherent viscosities up to 0.73 dL/g. The synthesis of substituted aryl ketones by the reaction of substituted benzoic acids with aryl compounds in PMMA was studied in detail to demonstrate the feasibility of the reaction for polymer formation. The thermogravimetry of the aromatic poly(thioether ketone)s showed a 10% weight loss in air and nitrogen at around 450 and 460°C, respectively. © 1992 John Wiley & Sons, Inc.     

Evolutionary dynamics of knowledge

This study discusses the evolutionary nature of knowledge acquisition at micro and macro levels, and in particular when the process involves an artificial agent's interpretative devices. In order to accomplish this, we propose using an individual learning model (or inner‐world reconstruction model) that in our view overcomes neoclassic epistemological holdups and may increase the predictive power of computational economics, by letting an artificial agent's knowledge evolve by itself, irrespective of globally specified goals or individual motives of behavior; using simultaneous (or parallel) genetic algorithms (GA) to evolve a single agent's learning strategy, each GA with different general specifications, in a multiagent setting. © 2006 Wiley Periodicals, Inc. Complexity 11: 12–19, 2006     

Sociology and Social Theory in Agent Based Social Simulation: A Symposium

A lengthy and intensive debate about the role of sociology in agent based social simulation dominated the email list simsoc@jiscmail.ac.uk during the autumn of 2000. The debate turned on the importance of models being devised to capture the properties of whole social systems and whether those properties should determine agent behaviour or, conversely, whether the properties of social systems should emerge from the behaviour and interaction of the agents and, if so, how that emergence should be represented. The positions of four of the main protagonists concerned specifically with the modelling issues are reprised and extended in this symposium.     

SiCp尺寸对SiCp／Cu基复合材料抗磨性能的影响

以纳米级(30nm)、亚微米级(130nm)、微米级(14μm)3种粒径的SiCp和微米级(10μm)铜粉为原料，用冷压烧结和热挤压方法制备了纳米、亚微米和微米级SiCp／Cu复合材料，考察了SiCp尺寸对SiCp／Cu复合材料抗磨性能的影响．结果表明，不同尺寸的SiCp颗粒作为增强相均能显著改善铜基复合材料的抗磨性能；随着SiCp尺寸的增大，SiCp／Cu复合材料的抗磨性能提高幅度显著增大，但偶件磨损表面的犁削加剧；以微米级SiCp为原料制备的SiCp／Cu复合材料的抗磨性能最佳，但其导致偶件40Cr钢犁削作用显著加剧．从摩擦副整体的摩擦磨损性能角度而言，宜采用SiCp尺寸为130nm的SiCp／Cu复合材料同40Cr钢组成摩擦副．