丙烯酸接枝乙丙共聚物的结构

丙烯酸接枝乙丙共聚物的结构李丽霞，尹志辉，綦玉臣，殷敬华（中国科学院长春应用化学研究所高分子物理开放实验室长春１３００２２）关键词ＥＰＭ，ＥＰＭ－ｇ－ＰＡＡ，异相成核剂，结晶温度聚烯烃是目前应用最为广泛的塑料之一，但由于它的非极性限制了它与金属和其它...     

Block copolymer libraries: modular versatility of the macromolecular Lego system

The synthesis and characterization of a new 4 x 4 library of block copolymers based on polystyrene and poly(ethylene oxide) connected by an asymmetrical octahedral bis(terpyridine) ruthenium complex at the block junction are described, while initial studies on the thin film morphology of the components of the library are presented by the use of Atomic Force Microscopy, demonstrating the impact of a library approach to derive structure-property relationships.     

镧对5CrNiMo模具钢的力学性能影响

研究了在5CrNiMo钢中分别加入3种不同含量稀土La后的强度、硬度、冲击韧性的变化。并在相同的热处理工艺条件下,与不添加稀土La的5CrNiMo钢进行对比。研究结果表明:稀土La加入量在适当的范围内可显著提高强度、硬度、冲击韧性,并且当稀土La加入量为0.033%(质量分数)时,5CrNiMo钢即可获得最好的综合机械性能。     

8-羟基喹啉-5-磺酸金属络合物的荧光特性及其应用研究

本文报道了8-羟基喹啉-5-磺酸的金属络合物在不同条件下的荧光特性,探讨了使用激光-时间分辨技术,建立镁、铝荧光分析方法的可能性.     

Toxic effect of triphenyltin on Lemna polyrhiza

Little data about toxic effect of triphenyltin (TPT) on aquatic plants is available. The purpose of this paper is to study the toxic effect of TPT on duckweed, Lemna polyrhiza, and the bioconcentration factor of TPT by Lemna polyrhiza. At 5 µg/l concentration TPT treatment, a toxic effect on growth of Lemna polyrhiza appeared. The 8 day IC₅₀ of TPT to Lemna polyrhiza was 19.22 µg/l. TPT stimulated peroxidase activity and nitrate reductase activity at 2 and 5 µg/l. TPT reduced chloroplast activity of Lemna polyrhiza at 2 and 5 µg/l. Bioconcentration factors of TPT for Lemna polyrhiza were 4.3 and 10.9 at 2 and 5 µg/l, respectively. Copyright © 2005 John Wiley & Sons, Ltd.     

Two-Dimensional Detergent Expansion Strategy for Membrane Protein Studies

Detergents are the most frequently applied reagents in membrane protein (MP) studies. The limited diversity of one-head-one-tailed traditional detergents, however, is far from sufficient for structurally distinct MPs. Expansion of detergent repertoire has a continuous momentum. In line with the speculation that detergent pre-assembly exerts superiority, herein we report for the first time cross-conjugation of two series of monomeric detergents for constructing a two-dimensional library of dimeric detergents. Optimum detergents stood out with unique preferences in the systematic evaluation of individual MPs. Furthermore, unprecedented hybrid detergents 14M8G and 14M9G enabled high-quality EM study of transporter MsbA and NMR study of G protein-coupled receptor A_2AAR, respectively. Given the abundance of cross-coupling chemistries, comprehensive diversity could be readily covered that would facilitate the finding of new detergents for the manipulation of thorny MPs and innovation of the functional and structural study in future.     

An Alkynyl-Dangling Ru(II) Polypyridine Complex for Targeted Antimicrobial Photodynamic Therapy

To realize clinical application of antibacterial photodynamic therapy (aPDT), one of the most arduous challenges is how to render aPDT agents high selectivity against bacterial pathogens. In light of the fact that amino group-containing lipids are rich on the outer surfaces of Gram-positive bacteria, we herein constructed an alkynyl-dangling ruthenium(II) polypyridine complex (Ru2) to preferentially label Staphylococcus aureus (S. aureus) and methicillin-resistant Staphylococcus aureus (MRSA) over mammalian cells via the amino-yne bio-orthogonal click reaction. Thanks to the strong singlet oxygen generation ability, Ru2 could photo-inactivate S. aureus and MRSA effectively and specifically. Phosphatidylethanolamine (PE) molecules also exist in mammalian cells but are not accessible for Ru2, leading to its poor binding/uptake and negligible cytotoxicity in the dark and upon irradiation towards mammalian cells as well as low hemolysis, all favorable for aPDT application.     

Electrochemical Detection of Tyrosinase in Cell Lysates at Functionalized Nanochannels via Amplifying of Ionic Current Response

Tyrosinase is an important enzyme in the metabolism of melanin and catecholamine, as well as an important antigen in autoimmunity of vitiligo. However, it is still a challenge to develop a selective and sensitive sensing approach for monitoring of tyrosinase in cell environment. In this work, a sensing strategy based on ion current rectification induced by nanochannels was established to electrochemically detect inactive tyrosinase. Functionalized alumina nanochannels were decorated by tyramine as an electrochemical platform to selectively determine tyrosinase via chemically specific reaction between phenolic hydroxyl groups of tyramine and tyrosinase. On the other hand, Fe²⁺ was further bonded with dihydroxyl groups generated by tyrosinase in nanochannels to amplify charge changes, resulting in the enhancement on the detection sensitivity for tyrosinase. Based on this principle, the developed electrochemical sensor showed a good linearity towards tyrosinase from 2 to 50 U/mL with a detection limit down to 0.83 U/mL, which can fulfil the requirement for detection of tyrosinase in cells. Eventually, the present electrochemical sensor was successfully employed in the selective and sensitive determination of tyrosinase in cell lysates. The results suggested that the activity of tyrosinase in B16 cells was 1.7-fold higher than that of Hela cells.     

肛周脓肿局部组织及外周血中IL-22 的表达及临床意义

目的 探讨细胞因子IL-22 在肛周脓肿局部组织及外周血中的表达和意义。方法 选取50例肛周脓肿患者（肛周 脓肿组）和50例无感染的混合痔患者（对照组）,两组患者均行手术治疗,并术中留取病变组织标本。术后观察患者转归,免疫组织化学法检测IL-22 表达、RT-PCR 法检测外周血单核细胞中IL-22 mRNA 的表达,观察IL-22 表达的变化及其与患者临床病理特征之间的关系。结果 IL-22在肛周脓肿组的表达阳性率高于对照组（P＜0.01）;肛周脓肿组根据不同转归分为治愈组、脓肿复发组、肛痿组,3 组患者IL-22 表达阳性率比较,治愈组显著降低,而肛瘘组最高（P＜0.01）。肛周脓肿组外周血单核细胞中IL-22 mRNA表达水平显著高于对照组（P＜0.01）;在肛周脓肿组中随着疾病的进展,肛瘘组患者外周血单核细胞中IL-22 mRNA表达水平显著高于治愈组（P＜0.01）。肛周脓肿组中IL-22的表达与患者性别、年龄均无关（均P ＞0.05）,而与脓肿直径（P＜0.01）、创面愈合时间（P＜0.05） 及进展为肛瘘有关（P＜0.05）。结论 IL-22在肛周脓肿局部组织及外周血中表达增强,在其发病机制中起了重要作用。     

Dispersed platinum supported by hydrogen molybdenum bronze-modified carbon as electrocatalyst for methanol oxidation

A new electrocatalyst, Pt/H_xMoO₃-C, for methanol oxidation, was prepared by dispersing platinum nano-particles on Vulcan XC-72 modified by hydrogen molybdenum bronze (H_xMoO₃, 0 ≤ x ≤ 2). The modification of Vulcan XC-72 with H_xMoO₃ on was accomplished by reducing the adsorbed molybdic acid and the platinum nano-particles were dispersed on the modified carbon by reducing chloroplatinic acid, with formaldehyde as the reductant. The prepared Pt/H_xMoO₃-C was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersion spectrometer, cyclic voltammetry (CV), chronoamperometry (CA), and single-cell test, with a comparison of the electrocatalyst, carbon-supported platinum (Pt/C) prepared under the same condition but without the modification. The results obtained from XRD and SEM showed that the modification of Vulcan XC-72 with H_xMoO₃ reduced the platinum particle size and improved distribution uniformity of platinum on carbon. The results, obtained from CV, CA, and the single-cell test, showed that Pt/H_xMoO₃-C exhibited better electrocatalytic activity toward methanol oxidation than Pt/C.