In vitro and ex vivo blood compatibility study of 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymer-coated hemodialysis hollow fibers

To identify the advantages of 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymer-coated polysulfone (PSf) hollow fibers for hemodialyzer and hemofilter minimodules with hollow fibers were made and blood compatibility was evaluated in vitro and ex vivo. Three types of hollow fibers, i.e., pure PSf (no additives), PSf alloyed with poly(1-vinyl-2-pyrrolidone) (PVPy), and PSf coated with the MPC copolymer, were processed in wet conditions. Commercially available hollow fibers (APS) were used as a control sample. The PSf hollow fibers have a condensed structure. A porous structure was observed when the PVPy was alloyed before wet processing, and no effect of the innercoated MPC copolymer on the porous structure was observed. One-tenth-sized minimodules of the conventional hemodialyzer were fabricated with 200 fibers each. The solute permeability of the hollow fibers was evaluated using 10% bovine serum in a buffer solution containing cytochrome C, which is a model protein of ₂-microglobulin. After circulation for 2.5h, the solute permeability of APS and PVPy-alloyed PSf hollow fibers decreased to 50% compared with their initial values. In contrast, the value for the hollow fibers innercoated with the MPC copolymer maintained its initial level. The inner surface of the dialysis membranes was observed with a transmission electron microscope and a layer of adsorbed protein on the PSf, APS, and PVPy-alloyed PSf hollow fibers was observed, but not on the MPC copolymer-coated fibers. Blood cell adhesion was then evaluated by circulation of whole rabbit blood without any anticoagulant ex vivo. Many adherent cells were observed on the PVPy-alloyed PSf hollow fibers; however, blood cells did not adhere or aggregate on the MPC copolymer-coated hollow fibers. From these results, we concluded that the in-situ coating of MPC copolymer on PSf hollow fibers is effective in preventing blood coagulation and maintaining the solute permeability of the fibers.     

纯钛表面激光合成钙磷生物陶瓷涂层的组成与结构

目的 采用廉价的CaCO_3和CaHPO_4·2H_2O作为原料,在激光的作用下通过反应制备HA生物陶瓷涂层。方法 利用X射线衍射仪和电子探针分析仪对涂层进行相分析、组织观察和成分分析。结果CaCO_3和CaHPO_4·2H_2O按20:80的质量比混合时,在功率为600W、扫描速度为3.5mm/s的激光作用下可一步合成钙磷生物陶瓷涂层。结论 在一定实验条件下,CaCO_3和CaHPO_4·2H_2O可合成组织致密、结合状态良好的钙磷生物陶瓷涂层。     

红霉素缓释微囊的制备及其释药机理的研究

本文旨在探讨红霉素微囊的制备及体外缓释机理。以明胶等为囊材,用红霉素制成微囊,研究微囊的厚度及孔隙度对药物释放速率的影响。进行理论分析,与实验结果相符性较好。     

锐钛型TiO_2性能研究 Ⅱ.锐钛型TiO_2的光化学活性封闭及其表征

用水热法ＳｉＯ２致密包覆封闭锐钛型ＴｉＯ２表面的光化学活性点,以Ｃｒ２Ｏ２－７的还原反应考察包覆层的致密性及包覆效果。讨论了ＴｉＯ２浆液的浓度、温度、ｐＨ及保温熟化等反应条件对ＳｉＯ２致密包覆的影响。     

H级无溶剂浸渍绝缘漆制备研究

以改性二苯醚树脂为原料,合成了一种新颖不饱和聚酯型无溶剂浸渍绝缘漆。它耐高温达到Ｈ级,固化速度快,贮存周期长,挥发率低。讨论了促进剂和挥发分抑制剂对无溶剂浸渍漆性能的影响,以及促进机理和抑制机理。结果证明了促进剂可以大大缩短固化时间,挥发分抑制剂在适当配比下,能够降低苯乙烯的挥发。     

基因转殖酵母菌培养液中生物素的高灵敏ELISA竞争测定法

目的　发展一种测定基因转殖酵母菌培养液中生物素的灵敏ELISA竞争测定法。方法　酶标板先用猪肺炎支原体包被 ,再依次用兔抗猪肺炎支原体抗血浆、羊抗兔IgG -生物素温育形成固态生物素 ,同溶液中的生物素 (标准液或试样 )竞争有限量的链霉亲和素 HRP。建立了在 5 0 - 2 0 0 0ng·L- 1 范围内生物素的标准曲线。结果　检测限为 83ng·L- 1 ,比文献报告的ELISA测生物素的最低测定浓度小 10 0 0倍。测定生物素浓度为 2 0 0、5 0 0、10 0 0ng·L- 1 的用空白培养液稀释的标准生物素试样的相对标准偏差分别是 2 4 87%、6 15 %、7 86 % ,平均回收率为 10 1 13%。在用本法测定野生酵母菌及其 6 3个基因转殖酵母菌培养液中的生物素时 ,发现 85 %以上的培养液试样中生物素浓度均得到不同程度扩增。结论　用猪肺炎支原体作包被蛋白 ,提高了ELISA结果的精确度和准确度 ,可供测定其它介质中生物素的参考     

薄膜包衣在中药防潮中的应用

中药制剂易吸潮严重影响药品的稳定性。简要介绍了中药制剂吸湿性原理、薄膜包衣的优点及应用现状,重点从薄膜包衣的成膜原理、处方组成、影响包衣制剂的工艺参数等方面综述薄膜包衣在中药防潮中的应用。综合国内外薄膜包衣分析技术并探讨其在中药防潮分析上的应用。近几年,虽然薄膜包衣已广泛应用于药物制剂,但由于中药成分的复杂性,薄膜包衣在中药防潮方面的研究和应用还不够深入。随着对新型薄膜包衣材料及在线分析技术的研究,薄膜包衣在中药方面的应用将得到进一步的关注,并将在中药现代化发展进程中发挥较大的潜力。     

Laser Surface Alloying of Sintered Stainless Steel

A characteristic feature of sintered stainless steel (SSS) is its porosity. Porosity results in a lower density of steel, making attractive components for producing lightweight structures and materials used in industry (e.g., the automotive industry or aerospace). Scientists also observe that porosity adversely affects steel’s properties, especially its strength properties. One of the proposals for improving the discussed properties is the use of surface treatment of sintered stainless steels, e.g., with the use of concentrated energy sources such as plasma beams or laser beams. However, this proposal is an incidental subject of research, which is not justified from the point of view of the obtained research results presented by a few research groups. In this study, the surface modification (surface treatment) of sintered stainless steel was presented. The authors proposed the use of two surface treatments in order to compare them and obtain the best results. The first treatment was the deposit of Cr₃C₂–NiCr coatings on SSS surfaces using the atmospheric plasma spraying (APS) method. The second treatment was to create surface layers on SSSs by laser alloying the surface with a CO₂ laser. Due to high precision and ease of automation, the most common methods in surface alloying treatment are laser technologies. This research’s main aim was to analyze the microstructure and strength properties of the SSS surface layer. The research confirms that applying the Cr₃C₂–NiCr coating and modifying the surface layer through the laser alloying method improves the mechanical properties of SSSs.     

Microstructure and Properties of WC/Ni-Based Laser-Clad Coatings with Different WC Content Values

The purpose of this work is to investigate the effect of the WC content on the surface characteristics and nanoindentation behaviors of WC/Ni-based composite laser-clad coatings. Four NiCrSiBC coatings with WC wt% of 30%, 40%, 50%, and 60%, respectively, were clad on carbon steel substrates using a laser. The morphologies and phase compositions of four clad coatings were comparatively observed. In addition, the hardness and elastic modulus values of the four coatings were measured and quantitatively calculated. As a result, with the increase in WC, the coating grains were more refined. Meanwhile, cracks and WC particle breakage occurred in the 50–60% WC coatings, whereas this was not found in the 30–40% WC coatings. When the WC content increased from 40% up to 50%, the coating hardness and elastic modulus significantly increased. However, a further increase in WC from 50% to 60% did not result in considerable improvement in coating quality but considerably worsened the coating’s cracking behavior instead. Therefore, for WC/Ni-based composite coatings, a threshold exists for the WC content, and this value was 50% within the experimental scope of this study.     

Passive Filler-Loaded Silicon Oxycarbide Coating on Nickle Alloy with High Thermal Shocking Behavior and Oxidation Resistance

Polymer-derived ceramic (PDC) coatings of considerable thickness can offer promising protection for metallic and superalloy substrates against oxidation and corrosion, yet the preparation remains challenging. Here, a SiOC/Al₂O₃/YSZ coating was prepared on a nickel alloy with a spraying method using Al₂O₃ and yttria-stabilized zirconia (YSZ) as passive fillers. The thickness can reach up to 97 μm with the optimal mass fraction and particle sizes of the passive fillers. A small or isolated SiOC phase is formed in the coating, which can effectively alleviate the shrinkage and cracking during the pyrolysis. The SiOC/Al₂O₃/YSZ coating exhibits low thermal conductivity and high bonding strength with the substrate. Moreover, the coating shows good thermal shock resistance between 800 °C-room temperature cycles and oxidation resistance at 1000 °C for 36 h. This work provides an effective guide for the design of thick PDC coatings to further promote their application in the thermal protective field.