2-Oxo-3,4-dihydropyrimido[4,5-d] pyrimidines as new reversible inhibitors of EGFR C797S (Cys797 to Ser797) mutant

Extensive structure-activity relationships (SARs) study of JND3229 was conducted to yield a series of new reversible 2-oxo-3,4-dihydropyrimido[4,5-d]pyrimidine privileged scaffold as EGFR^C797S inhibitors. One of the most potent compound 6i potently suppressed EGFR^{L858R/T790M/C797S} kinase with an IC₅₀ value of 3.1 nmol/L, and inhibited the proliferation of BaF3 cells harboring EGFR^{L858R/T790M/C797S} and EGFR^{19D/T790M/C797S} mutants with IC₅₀ values of 290 nmol/L and 316 nmol/L, respectively. Further, 6i dose-dependently induced suppression of the phosphorylation of EGFR^{L858R/T790M/C797S} and EGFR^{19D/T790M/C797S} in BaF3 cells. Compound 6i may serve as a promising lead compound for further drug discovery overcoming the acquired resistance of non-small cell lung cancer (NSCLC) patients.     

Recent advances in the synthesis of well-defined glycopolymers

Glycopolymers are receiving increasing interest due to their application in areas, such as glycomics, medicine, biotechnology, sensors, and separation science. Consequently, new methods for their synthesis are constantly being developed, with an increasing emphasis on the preparation of well-defined polymers and on the production of complex macromolecular architectures such as stars. This review covers recent developments in the synthesis of glycopolymers, with a particular emphasis on (i) the use of controlled radical polymerization to prepare well-defined glycopolymers from unprotected monomers and (ii) postpolymerization modification strategies using reactive polymer precursors (including “click” reactions). Recent work on the production of glycosylated polypeptides, which are under investigation as mimics of naturally occurring glycoproteins, is also included. The authors offer some suggestions as to future developments and remaining challenges in this topical area of polymer chemistry. © 2007 Wiley Periodicals, Inc. J Polym Sci PartA: Polym Chem45: 2059–2072, 2007     

Laboratory investigation of biodegradability of a polyurethane foam under anaerobic conditions

Polyurethane (PU) foams can be used in many remediation applications as an isolation material to prevent the release of hazardous materials into the environment. The integrity of a PU foam was investigated in this study using short-term accelerated laboratory experiments including bioavailability assays, soil burial experiments, and accelerated bioreactors to determine the fate of PU foam in the soil where anaerobic processes are dominant. The experimental results have shown that the studied PU foam is likely not biodegradable under anaerobic conditions. Neither weight loss nor a change in the tensile strength of the PU material after biological exposure was observed. The FT-IR chemical signature of the PU foams was also nearly identical before and after biological exposure. The composition of the PU material (aromatic polyester and polyether PU) used in this study could have played a significant role in its resistance to microbial attack during the short-term accelerated experiments.     

Surface-grafted polystyrene beads with comb-like poly(ethylene glycol) chains: preparation and biological application

We prepared surface-grafted polystyrene (PS) beads with comb-like poly(ethylene glycol) (PEG) chains. To accomplish this, conventional gel-type PS beads (35-75 microm) were treated with ozone gas to introduce hydroperoxide groups onto the surface. Using these hydroperoxide groups, poly(methyl methacrylate) (PMMA, Mn= 22,000-25,000) was grafted onto the surface of the PS beads. The ester groups of the grafted PMMA were reduced to hydroxyl groups with lithium aluminum hydride (LAH). After adding ethylene oxide (EO) to the hydroxyl groups, we obtained the PS-sg-PEG beads, which had a rugged surface and a diameter of 80-150 microm. We could obtain several kinds of the PS-sg-PEG beads by controlling the chain lengths of the grafted PMMA and the molecular weights of the PEG chains. The grafted PEG layer was about 30-50 microm thick, which was verified from the cross-sectioned views of the fluorescamine-labeled beads. These fluorescence images proved that the beads possessed a pellicular structure. Furthermore, we found that the surface-grafted PEG chains had the characteristic property of reducing non-specific protein adsorption on the beads.     

降脂经验方降脂作用的临床观察

采用自拟的降脂方治疗血胆增高患者６３人，并与用月见草油胶丸治疗患者６１人比较，前者疗效优于后者，两组有显著性差异。     

Application of HPLC to measure vanadium in environmental,biological and clinical matrices

Vanadate and vanadium compounds exist in many environmental, biological and clinical matrices, and despite the need only limited progress has been made on the analysis of vanadium compounds. The vanadium coordination chemistry of different oxidation states is known, and the result of the characterization and speciation analysis depends on the subsequent chemistry and the methods of analysis. Many studies have used a range of methods for the characterization and determination of metal ions in a variety of materials. One successful technique is high performance liquid chromatography (HPLC) that has been used mainly for measuring total vanadium level and metal speciation. Some cases have been reported where complexes of different oxidation states of vanadium have been separated by HPLC. Specifically reversed phase (RP) HPLC has frequently been used for the measurement of vanadium. Other HPLC methods such as normal phase, anion-exchange, cation-exchange, size exclusion and other RP-HPLC modes such as, ion-pair and micellar have been used to separate selected vanadium compounds. We will present a review that summarizes and critically analyzes the reported methods for analysis of vanadium salts and vanadium compounds in different sample matrices. We will compare various HPLC methods and modes including sample preparation, chelating reagents, mobile phase and detection methods. The comparison will allow us to identify the best analytical HPLC method and mode for measuring vanadium levels and what information such methods provide with regard to speciation and quantitation of the vanadium compounds.     

Electrochemical technique for the determination of fractal dimension of dental surfaces

Fractal dimension of a carious tooth surface was determined using an electrochemical method. The method was based on time-dependent diffusion towards electrode surfaces, which is one of the most useful and reliable methods for the determination of fractal dimension of electrode surfaces. For this purpose, the tooth was covered with a gold layer, which acted as an electrode in electrochemical experiments. It is suggested that the fractal dimension can be used as a quantitative measure of the state of dental surfaces. The method presented demonstrates the power of electrochemical techniques for the determination of fractal dimension of surface of non-conducting objects.     

Synthesis and characterization of biocompatible poly (L-lactide) using zinc (II) salen complex

Abstract

A biocompatible zinc (II) complex based on a tetradentate N,N,O,O-type salen ligand was synthesized, characterized and used for the solvent-free ring-opening polymerization (ROP) of L-lactide in bulk at 180?°C to prepare high molecular weight poly(L-lactide) (M_n : 82,600?Da; M_w : 140,000?Da; PDI: 1.70). Poly(L-lactide) (PLLA) was characterized using FTIR, ¹H NMR, ¹³C NMR, GPC, TGA, DSC, WAXD, and MALDI-ToF. Kinetic measurement was carried out and first-order behavior to monomer was observed. The k _app was found as 6?±?0.001?×?10^?4?s^?1. The biocompatibility of the PLLA was confirmed by in vitro cytotoxicity against NIH/3T3 fibroblast cell line and can be used in biomedical applications.     

环境扫描电镜及其应用

叙述了环境扫描电镜（ＥＳＥＭ）的成像原理———电子信号气体放大原理及其与常规扫描电镜（ＳＥＭ）的区别，介绍了我国第一台带高温台的ＥＳＥＭ．综述了近年来国外学者应用ＥＳＥＭ开展的一些研究工作．介绍了中国科学院化工冶金研究所应用ＫＹＫＹ１５００型ＥＳＥＭ对金属表面氧化反应中晶须／晶粒生长过程的研究     

Recent Progress on Infrared Photoacoustic Spectroscopy Techniques

Abstract

Analogous to most new methods in science, photoacoustic spectroscopy (PAS) grew out of an advance in technology, in this case the dramatic improvement in novel light sources, modulators, and acoustic detectors, as well as signal recovery electronics, which in turn was made possible by the development of modern PAS techniques. PAS is a promising technique that can be used to analyze and characterize a broad variety of objects (gaseous, solid, and liquid samples). In the present review, the recent development of infrared PAS limited to the general area of gas-phase analysis techniques since 1990 is summarized, with special emphasis on the development of new or enhanced analytical methodologies based on the use of the photoacoustic (PA) effect to improve the sensitivity of PAS by enhancing signal or reducing noise levels, with regard to PA systems, applications, and conclusions. The applications of these novel PA methods are mainly concerned with molecular spectroscopic, industrial, atmospheric, environmental, chemical and biological, and medical and clinical analysis. New prospects and challenges in various application fields of PAS technique are described.