A study on poly (N-vinyl-2-pyrrolidone) covalently bonded NiTi surface for inhibiting protein adsorption

Near equiatomic NiTi alloys have been extensively applied as biomaterials owing to its unique shape memory effect, superelasticity and biocompatibility. It has been demonstrated that surfaces capable of preventing plasma protein adsorption could reduce the reactivity of biomaterials with human blood. This motivated a lot of researches on the surface modification of NiTi alloy. In the present work, following heat and alkaline treatment and silanization by trichlorovinylsilane (TCVS), coating of poly (N-vinyl-2-pyrrolidone) (PVP) was produced on the NiTi alloy by gamma ray induced chemical bonding. The structures and properties of modified NiTi were characterized and in vitro biocompatibility of plasma protein adsorption was investigated. The results indicated that heat treatment at 823 K for 1 h could result in the formation of a protective TiO2 layer with “Ni-free” zone on NiTi surface. It was found that PVP was covalently bonded on NiTi surface to create a hydrophilic layer for inhibiting protein adsorption on the surface. The present work offers a green approach to introduce a bioorganic surface on metal and other polymeric or inorganic substrates by gamma irradiation.     

Preparation and characterization of cobalt-doped iron pyrite(FeS_2) thin films

Iron pyrite (FeS_2) incorporated with cobalt dopant varying from 2%to 6%atomic ratio,was synthesized by using an aqueous hydrothermal process.The thin films of Co-doped FeS_2were fabricated by a vacuum thermal evaporation of synthesized FeS_2powder.The structural,electrical and optical properties of as-deposited and sulfurized films were investigated.The X-ray diffraction results indicated that the synthesized powder and thin films showed a cubic pyrite structure.The crystallinity of FeS_2was slightly degraded by the doping of cobalt.The dependence of thin-film resistance on the temperature indicated an increase of activation energy until 3 at%cobalt doping and then decreased the resistance with the increase of cobalt concentration.Hall effect measurements showed that the Co-doped samples have n-type conduction except for the 2 at%.The carrier concentration was in the order of 10~(18)cm~(-3),whereas,the carrier mobility decreased from 6.52 cm~2/V.s to 4.3 cm~2/V.s with the increase of cobalt dopant.The photosensitivity of undoped and cobalt-doped FeS_2films was measured under AM 1.5G and NIR light.The sulfurized films showed a higher photoresponse than the asdeposited films for both visible and IR lights.     

Recent progress on the hydrogen storage properties of ZrCo-based alloys applied in International Thermonuclear Experimental Reactor (ITER)

Under the development of International Thermonuclear Experimental Reactor (ITER) system aimed at realizing the controllable fusion reaction to solve the energy crisis fundamentally, there is an urgent need to find an appropriate material for tritium handling. ZrCo alloy is considered to be a promising candidate for the storage and delivery of hydrogen isotopes due to the favorable characteristics such as low plateau pressure for absorption, high dissociation pressure at moderate temperature and better ability of trapping 3He. However, the hydrogen induced disproportionation and the slower recovery/deliverty rate of ZrCo-based alloys have limited their further application in ITER system. This review summarizes the efforts towards enhancing the hydrogen storage properties of ZrCo-based alloys including element substitution, surface modification, disproportionation mechanism investigation and the isotope effect study. Element substitution and surface modification play positive role to improve the anti-disproportionation ability and kinetic property of the alloys. However, the ZrCo-based alloys require to be further modified by more attempts such as new composition, novelty modification method or catalyst addition in order to better satisfy the application demands for tritium handling. Moreover, new insight for further understanding the inner disproportionation mechanisms of this material is needed by combining the advance characterization and theoretical analysis, which is in favor of addressing the disproportionation problem of the ZrCo-based alloys essentially.     

Hybrid solar cells based on poly（3-hexylthiophene） and electrospun TiO2 nanofibers modified with CdS nanoparticles

Organic–inorganic hybrid solar cells based on poly(3-hexylthiophene) and electrospun TiO2 nano bers were fabricated by solution process.The ef ciency of the device was improved by modifying CdS nanoparticles on the surface of TiO2 by electrochemical method.The CdS layer can lead to the increase of both open circuit voltage and short circuit current of the device,which are attributed to enhanced exciton dissociation and light absorption and suppressed carrier recombination by CdS at the heterojunction.However,too thick CdS layer led to increased series resistance and decreased ef ciency of the device.Therefore,the optimum condition of the CdS deposition was obtained,which increased the power conversion ef ciency of the device for about 50%.Our results indicate that the surface modi cation on the inorganic semiconductor layer is an effect way to improve the performance of the hybrid solar cells.     

Ionic iron（III） complex of aryloxo-linked bis（imidazolium） cations： efficient and recyclable catalyst for aryl Grignard cross-coupling of alkyl chlorides

A novel phenol-linked bis（imidazolium） salt, H3LCl2 （L = O-4-C（CH3）3-C6H2-2,6-di[CH2{C（NCHCH- NAr）}]2, Ar = 2,6-diisopropylphenyl, 1）, was designed and used to prepare an ionic iron（III） complex [H2L][FeCl4] （2）. Complex 2 was a highly efficient catalyst for aryl Grignard cross-coupling of alkyl chlorides bearing β-hydrogens. Furthermore, complex 2 was reusable and could be reused in at least eight times without significant loss in catalytic activity.     

Protein adsorption on the poly（L-lactic acid） surface modified by chitosan and its derivatives

Surface modification of biomaterials has been adopted over the years to improve their biocompatibility. In this study, aiming to promote hydrophilicity and to introduce natural recognition sites onto poly（L-lactic acid） （PLLA） films, chitosan and its derivatives, carboxymethyl chitosan（CMC） and N-methylene phosphonic chitosan （NPC）, were used to modify the surface of PLLA films by an entrapment method. Radiolabeled （^125I） proteins were used to measure the amount of protein adsorbed to PLLA surfaces. Fibronectin （Fn） was used to study the protein adsorption on the modified PLLA surfaces, including isotherm adsorption and adsorption kinetics of single protein, competitive adsorption of binary proteins system and serum multi-proteins and the desorption behavior in serum solution. The results showed that in the isotherm adsorption, Fn had a larger adsorption capacity on the CS-modified surface at lower concentrations, but had a high adsorption capacity at CMC-modified surface at higher concentrations. In the study of absorption kinetics, Fn had a fastest adsorption equilibrium and a highest equilibrium adsorption capacity at the CS-modified surface, while it was opposite at the PCS-modified surface. When BSA and serum were added, it had the greatest effect on the adsorption of Fn on the PCS-modified surface. After 6 hours soaking in the desorpUon study, Fn had reached desorption equilibrium on all the modified surfaces, which had different effects on the desorption rate and the remaining percentage of Fn.     

Synthesis,characterization, and tunable wettability of poly(ionic liquid) brushes via nitroxide-mediated radical polymerization (NMP)

Well-defined poly (ionic liquid) brushes with tunable wettability are successfully synthesized via nitroxide-mediated radical polymerization. X-ray photoelectron spectroscopy, attenuated total reflection infrared spectroscopy and static water contact angle measurements are used to monitor each step. Ellipsometry, nuclear magnetic resonance (1H and 13C) spectra and gel permeation chromatographic measurements reveal that there is a linear increase in polymer film thickness with polymerization time, indicating that chain growth from the surface is a controlled/“living” polymerization. The surface morphology was measured by atomic force microscopy. Moreover, the surfaces of the poly (ionic liquid) brushes with tunable wettability and reversible switching between hydrophilicity and hydrophobicity can be easily achieved by counteranion exchange.     

鸡形觉剥夺性近视眼发病机制的研究

目的探索形觉剥夺性近视眼的发病机制。方法利用眼罩遮盖造成鸡近视模型，并利用高效液相色谱和电化学检测技术研究了鸡形觉剥夺性近视视网膜多巴胺及其代谢产物的变化。结果形觉剥夺性近视鸡实验眼与对照眼比较，在屈光度、前后径、赤道径方面有极显著差异。在多巴胺及其代谢产物含量方面亦有极显著差异。更为重要的是，实验发现5-羟色胺产物5-HIAA实验眼与对照眼比较亦有显著性差异。结论多巴胺参与正常视觉和眼球生长发育的调控。5-羟色胺可能作为一种神经递质参与了形觉剥夺性近视的形成。     

热处理对于TiNi(Ni原子分数为50.6%)合金性能的影响

介绍了固熔热处理工艺对用于制造医用支架直径为 0 .8mm的TiNi(Ni原子分数为 5 0 .6 % )合金的影响 .研究的目的在于找到适合自扩张支架的马氏体相变完成温度Af.采用低温下时效处理的办法 ,在高低温度下对样品进行连续弯曲训练 ,以此来获得双向形状记忆效应 .通过不同的固熔热处理温度 ,发现合金完成马氏体相变时存在约 2 0℃的温度变化范围 ,且具有较好的形状回复率 .     

木质素接枝右旋聚乳酸的结晶行为及对左旋聚乳酸的结晶促进作用

木质素（lignin）作为仅次于纤维素的第二大可再生生物质资源,近年来受到广泛关注并已被应用于高分子材料的改性。本文在对碱木质素烷基化修饰的基础上,利用其丰富的羟基对右旋丙交酯进行开环聚合,制备了一系列不同分子量的烷基化木质素接枝右旋聚乳酸（LGPD）。通过对LGPD自身结晶行为的研究表明,木质素的存在能够促进右旋聚乳酸（PDLA）的结晶,提高其吸收紫外线的能力。相对于4臂右旋聚乳酸（4a-PDLA）,将LGPD作为添加剂加入到左旋聚乳酸（PLLA）后更有利于立构复合晶的形成,从而进一步提高了共混材料的结晶能力。     

催化过氧化氢氧化钙黄绿素褪色光度法测定痕量铁

基于Fe(Ⅲ)对过氧化氢氧化钙黄绿素的催化反应,建立了高灵敏测定痕量铁的新方法.本法线性测定范围为0.4～4ìg/L,检出限为1.4х10-10g/mL,线性回归方程为ΔA=-0.0033 0.03812CFe3 (ìg/L),相关系数r=0.9991.本法已用于人发、茶叶中铁含量的测定,结果满意.     

聚甲基乙撑碳酸酯的改性研究进展

二氧化碳可降解塑料聚甲基乙撑碳酸酯(PPC)以其优良的生物可降解性,高阻隔性和生物兼容性等优点而备受关注.近年来,PPC的工业化生产试验稳步推进,对PPC的研究报道也越来越多.本文结合近年来有关PPC的报道,从物理改性和化学改性两方面介绍了PPC的最新研究进展.     

冠脉药物涂层支架在冠心病的应用研究

目的:探讨雷帕霉素药物洗脱支架(CypherTm)在冠心病(CHD)冠状动脉介入治疗中应用的安全性和有效性.方法:以2004年5月至2005年5月在我科住院的31例植入雷帕酶素支架35枚的冠心病病人作为研究组,以1999年1月至2003年12月在我科住院的30例植入非药物支架的冠心病病人作为对照组.结果:研究组与对照组支架置入的成功率均为100%.研究组一年后再狭窄率0%,对照组一年后再狭窄率13.3%.结论:经皮冠状动脉内支架植入治疗安全可行、疗效确切,药物洗脱支架对防止再狭窄有独到之处.     

三乙烯四氨基红麻纤维的制备及其对Cu2+、Zn2+、Ni2+的吸附性研究

红麻纤维经环氧基活化后与三乙烯四胺接枝反应,制得一种改性红麻纤维;测定了该纤维对Cu2 、Zn2 、N i2 的吸附性能.结果表明:在一定条件下,改性纤维对Cu2 、Zn2 的吸附性能较好,对N i2 的吸附性能一般.     

Study on Synthesis and Characterization of Functional PS Microspheres Modified by Polyperoxide (PPX)

Peroxy functionalized polystyrene core was synthesized by emulsion polymerization using PPX as inisurf. The second stage polymerization was carried out by direct grafting of shell monomers (BuA and MMA) to the surface of functionalized PS seed latex particles which contain labile peroxy groups. The reaction kinetics of both of the two stage polymerization, the particle size measurement, DSC analysis were given.     

煤吸附解吸电磁改性及定量分析

用容量法对焦作朱村矿变质无烟煤在不同频率的交变电磁场中吸附解吸特征进行了研究。实验结果表明：不同频率的交变电磁场作用下，煤吸附C02、N2仍旧符合Langmiur方程；交变电磁场减弱了煤的吸附能力，减小了吸附常数b值，但饱和吸附量(a值)基本上不变．是典型的表面改性现象，并从量的角度分析其改性的程度。     

新鲜多孔硅(001)表面结构与电子特性理论研究

在周期边界条件下的k空间中,采用基于密度泛函理论的广义梯度近似(GGA)平面波超软赝势法,建立H12S i31几何模型来对表面主要被H覆盖的新鲜多孔硅(Porous S ilicon,PS)(001)表面最外层的S i—H键的几何结构和电子特性进行初步的理论研究.计算得到氢化PS(001)表面几何结构S i—H键长为0.148 nm、H—S i—H键角为106°,并通过原子布居数、电子密度图分析得到氢化PS表面原子的电子特性.     

聚结晶紫薄膜修饰电极对多巴胺与尿酸的电催化作用

利用循环伏安法制备了聚结晶紫薄膜修饰电极(PCVE),详细研究了该修饰电极对生物分子多巴胺(DA)和尿酸(UA)的电催化作用.结果表明,PCVE对DA和UA具有较强的电催化作用,并且对抗坏血酸(AA)具有较强的抗干扰作用,允许高达1 000倍以上AA存在而不干扰痕量DA的测定.将PCVE结合差分脉冲伏安(DPV)技术,对DA的检测线性范围为4.0×10-7 mol/L~2.5×10-5 mol/L,检测限可达3.5×10-8 mol/L;对UA的检测线性范围为5.0×10-7 mol/L~5.0×10-5 mol/L,检测限达5.0×10-8 mol/L.利用该法可以对DA和UA进行同时测定,将该法用于尿液中尿酸的测定,取得满意结果.     

硅藻土过滤除铁研究

根据以硅藻土过滤（以下简称ＤＥＦ）方法去除水中铁质的实验研究，重点分析了在不同预涂剂、附加剂和起始滤速下，铁的去除效果和过滤水头损失及滤速的变化，并对ＤＥＦ除铁机理作了初步探讨，结果表明，ＤＥＦ技术是一种有效的除铁方法，实验所用硅藻土由宁波染化厂生产。     

硬脂酸改性Mg(OH)2的机理及对EVA性能的影响

采用FTIR表征硬脂酸对氢氧化镁Mg(OH)₂的改性效果，发现不存在一个所谓的“最佳量”，分析认为硬脂酸对Mg(OH)₂表面改性既包括着 硬脂酸—COOH与Mg(OH)₂的—OH之间的弱酯化反应，也包含着酸与弱碱Mg(OH)₂之间的酸碱反应，所以硬脂酸对Mg(OH)₂的表面改性随硬脂酸用量 增加而持续进行。此外，改性剂用量也对Mg(OH)₂填充乙烯-醛酸乙烯酯共聚物(EVA)体系性能存在显著的影响。与填充未处理Mg(OH)₂体系相比 较，表面改性剂用量的增加会导致复合材料的拉伸强度的不断下降，断裂伸长率的增加和阻燃性能的急剧恶化。但是，复合材料的表观黏度下 降，加工性能得到改善。