Novel sequence for generating glycopolymer tethered on a membrane surface

Cell surface carbohydrates, usually binding with other biomacromolecules (such as lipids and proteins), are involved in numerous biological functions, including cellular recognition, adhesion, cell growth regulation, and inflammation. Synthetic carbohydrate-based polymers, so-called glycopolymers, are emerging as important well-defined tools for investigating carbohydrate-based biological processes and for simulating various functions of carbohydrates. In this study, a novel two-step sequence for the generation of a glycopolymer layer tethered on a polypropylene microporous membrane is described. First, a UV-induced graft polymerization of 2-aminoethyl methacrylate hydrochloride (AEMA) was carried out on the membrane to generate an amino-functionalized surface, and the effects of polymerization factors (monomer/initiator concentration and UV irradiation time) on the grafting density were studied. Second, sugar moieties were bound with the grafted functional layer to form glycopolymer by the reaction between the amino groups on the membrane surface and carbohydrate lactones. Chemical analysis by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy combined with surface morphology observation by scanning electron microscopy confirmed the graft polymerization of AEMA and the formation of glycopolymer. The decreases of water contact angle and protein adsorption on the membrane revealed the enhancement of hydrophilicity and protein resistance due to the typical characteristics of the glycopolymer tethered on the surface. These results indicated that the novel sequence reported in this work is a facile process to form glycopolymer-modified surfaces.     

A convenient catalytic approach to synthesize straight boron nitride nanotubes using synergic nitrogen source

Straight boron nitride nanotubes (BNNTs) with pure hexagonal phase were conveniently prepared by heating the mixture of Mg(BO₂)₂ · H₂O, NH₄Cl, NaN₃ and Mg powder in an autoclave at 600 °C for 20–60 h. These BNNTs had diameters mainly ranging 30–300 nm and lengths up to 5 μm, and a majority of them had at least one closed end. Besides the traditional end tips, additional cone-like tips were frequently found to be attached on the BNNTs. The effects of temperature, reactants and the possible mechanism of the catalytic formation of the BNNTs are discussed.     

Immobilization of Polymer-Stabilized Noble Metal Colloids and Their Catalytic Properties for Hydrogenation of Olefins

Polymer-stabilized noble metal colloids were efficiently immobilized on silica by the addition of organic acids under mild conditions. The function of organic acids in the immobilization was studied by infrared spectroscopy. Transmission electron micrographs indicate that the immobilized colloids have a controlled particle size and size distribution. They serve as catalysts in the hydrogenation of cyclohexene and cyclopentadiene, the results of which show that this new type of immobilized colloid has high selectivity and good stability.     

Extraction Kinetics of Rare Earth Elements with sec—Octyl—phenoxy Acetic Acid

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对称性和配合物的构型——Ⅱ.混合配体配合物

从库仑定律出发,采用最优化法,计算了MLaL_b′型配合物各种几何异构体的几何构型稳定化能。在计算中考虑了配体L、L′的相对电荷。 计算结果表明,对称性是决定构型的首要因素。具体构型与配体的相对电荷有关。 在若干配合物中,中心原子的dⁿ构型决定其构型的骨架。 配体对构型的作用也应予考虑。对共价性程度大的配合物,应考虑轨道重叠对构型的影响。     

Synthesis and Characterization of Ag2S Nanocrystals in Hyperbranched Polyurethane at Room Temperature

Ag₂S nanoparticles in hyperbranched polyurethane matrix were prepared through the in situ reaction with thioacetamide as the sulfur source at room temperature. Transmission electron microscopic analysis revealed a uniform spherical shape for Ag₂S nanoparticles, with an average size of about 4-10 nm and a narrow size distribution. X-ray powder diffraction and UV-vis spectroscopy were also used to characterize the obtained nanoparticles     

手性聚甲基丙烯酸酯液晶聚合物的合成及相行为的研究

手性聚甲基丙烯酸酯液晶聚合物的合成及相行为的研究向前，张纪宇，张树范（中国科学院化学研究所北京１０００８０）关键词手性液晶聚合物，相行为手性侧链液晶聚合物在侧链中含有不对称碳原子的末端基，使聚合物显示Ｓｔ相．Ｓ？相层中的分子呈倾斜排列而产生自发极化．...     

新型吸附剂——球形碳化树脂的研究Ⅲ.

聚偏二氯乙烯球体经185℃预裂解后,进行960℃高温裂解,得到0.6—0.8mm粒径的球形碳化吸附树脂,碳收率为74％以上。碳化吸附树脂机械强度好,比表面为1,000M~2/g以上,对肌酸酐吸附率可达99％。     

一种转基因猪血中重组人血清白蛋白分离纯化新方法

基因工程技术已经成为研究和生产重组人血清白蛋白(rHSA)替代人血清白蛋白(HSA)的重点技术,而白蛋白的纯化则是该技术的关键。本文主要介绍了从转基因猪血中纯化rHSA的一种新方法,即热乙醇沉淀与多级色谱分离相结合的rHSA纯化方法。热乙醇沉淀法可从猪血浆中获得rHSA粗提取液,此时rHSA的纯度可达69.5%,回收率达51.3%。进一步采用多级色谱分离法,即阴离子交换色谱和反相色谱法进一步纯化,得到rHSA的最终纯度约为100.0%,总回收率为41.1%。该方法为从转基因猪血浆中大规模纯化用于临床和生化研究的高纯度rHSA提供可能,同时也为rHSA替代HSA奠定了基础。     

纳米尺寸团簇NinZrn(n=3～5)的几何结构与成键规律研究

根据化学键理论与拓扑原理，设计了团簇NinZrn(n=3-5)的可能几何构型，并用从头算方法进行构型优化，结果表明，由NiZr组成的团簇原子间的Zr-Zr和Zr-Ni键明显较强，而Ni-Ni的成键较弱，并发与NinZrn(n=3-5)团簇电子性质与有机烯烃分子等瓣相似，原子之间的成键按照强弱相间的规则分布。