缓释材料用量对水溶性药物骨架片释放度的影响

水溶性药物卡托普利（Captopril,Cap）是第一代血管紧张素转换酶抑制剂,是治疗高血压的首选药物之一．常用剂型为糖衣片或普通片,由于其生物半衰期短,需要Ft服三次,且峰谷浓度差别较大,这可能是引起肺淤血、眩晕、头疼、肠胃道紊乱等不良反应的原因,有必要将其制为缓释剂型．国外已有Cap缓释胶囊上市,由于水溶性药物本身溶出很快,其释放较难被阻滞,国内尚无Cap的缓释品种上市．本实验参考国内外Cap缓释制剂的处方和制备工艺,筛选研制了Cap缓释骨架片．     

超高分子量聚乙烯纤维复合材料的研究进展

概述超高分子量聚乙烯（UHMWPE）纤维增强复合材料的研究进展,详细介绍了UHMWPE纤维的各种优良特性和UHMWPE纤维增强复合材料用基体树脂,以及UHMWPE纤维增强复合材料的制备方法与工艺,对UHMWPE增强复合材料的应用及其应用领域进行了汇总。     

新型胶原基人工皮肤模型的建立

根据皮肤的组织结构与生理功能,研制了复合天然三维网络结构胶原组织工程支架材料,并以此为支架材料建立了3层结构的人工皮肤模型:上层是具有良好生物相容性且可降解的聚合物涂层,可以屏蔽细菌并保持人工皮肤良好的透水气性;中间是复合型天然三维网络结构胶原纤维支架材料层,为细胞的增殖提供三维空间和良好的生长环境,起到真皮基质的作用;下层是药物层,具有营养、抗菌消炎、刺激细胞生长的作用。     

Oligosaccharide mimics containing galactose and fucose specifically label tumour cell surfaces and inhibit cell adhesion to fibronectin

With the aim of establishing a versatile and easy synthesis of branched saccharides for biological applications, we used molecular-dynamics simulations to model Lewis(y) to two classes of di- or triantennary saccharide mimetics. One set of mimetics was based on 1,3,5-tris(hydroxymethyl)cyclohexane (TMC) as the core, the other on furan, and both were derivatised with galactose and/or fucose. The TMC-based saccharides were biotinylated, while the furan disaccharides were treated with maleimide-activated biotin in a Diels-Alder fashion to yield oxazatricyclodecanes (OTDs). These were then assayed as cell-surface labels in human colon (SW480 and CaCo-2), liver (PLC), Glia (U333 CG 343) and ovary (SKOV-3) tumour cell lines. Discrete staining patterns were observed in all cells, usually at one or two poles of the cells, particularly with the asymmetric 3-beta-L-fucopyranosyloxymethyl-4-beta-D-galactopyranosyloxymethyl-OTD. Normal SV40-transformed fibroblasts (SV80) showed no staining. Adhesion of the highly metastatic mouse melanoma line B16 F10 to fibronectin was inhibited by 80 % by the TMC-digalactoside and by 30 % by 3,4-bis-(beta-D-galactopyranosyloxymethyl)furan. None of the saccharide mimetics inhibited the adhesion of the less metastatic B16 F1 line. Migration of B16 F10 cells through Matrigel was greatly inhibited by the TMC-digalactoside and weakly inhibited by the TMC-trigalactoside. The saccharide mimetics that had shown the best structural agreements with the terminal saccharides of Lewis(y) in the molecular dynamics simulation were also the most biologically potent compounds; this underlines the predictive nature of molecular dynamics simulations. The use of the non-saccharide cores enabled us to adapt spacer lengths and terminal saccharides to optimise the structures to bind more avidly to cell-surface lectins.     

Ethyl methacrylate grafted on two starches as polymeric matrices for drug delivery

The use of copolymers grafted on starch for controlled‐release technology is an interesting proposal, since a modification of a natural polymer is more suitable than synthetic polymers because of its biocompatibility and biodegradability. The aim of this paper is to synthesize acrylic polymers grafted on carbohydrates to investigate the release kinetic of different solubility drugs from polymeric matrix systems and to observe the effect of grafted copolymers and drug solubility on the release mechanism. Copolymer variables such as carbohydrate content, stereoregularity of grafted chains, particle size, morphology, sensitivity to hydration, and rheological properties are discussed. Tablets were prepared by direct compression of the graft copolymer and drug. The drugs' release in vitro kinetics was studied by dissolution testing. Drug release from tablets depends on polymer matrix, polymer content, drug, and pH. An increase in drug solubility results in an increase in the rate of dissolution, as in the case of a poor hydrophilic matrix. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 523–536, 2005     

Effect of layering pattern on dynamic mechanical properties of randomly oriented short banana/sisal hybrid fiber–reinforced polyester composites

Dynamic mechanical test methods have been widely employed for investigating the structures and viscoelastic behavior of polymeric materials to determine their relevant stiffness and damping characteristics for various applications. Randomly oriented short banana/sisal hybrid fiber–reinforced polyester composites were prepared by keeping the volume ratio of banana and sisal 1 : 1 and the total fiber loading 0.40 volume fraction. Bilayer (banana/sisal), trilayer (banana/sisal/banana and sisal/banana/sisal), and intimate mix composites were prepared. The effect of layering pattern on storage modulus (E′), damping behavior (tan δ), and loss modulus (E″) was studied as a function of temperature and frequency. Bilayer composite showed high damping property while intimately mixed and banana/sisal/banana composites showed increased stiffness compared to the other pattern. The Arrhenius relationship has been used to calculate the activation energy of the glass transition of the composites. The activation energy of the intimately mixed composite was found to be the highest. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2168–2174, 2005     

Distribution of mono‐ and di‐methacrylic monomers in SBS block copolymer and its influence on the photopolymerization process

Persoz hardness measurements and the analysis of the temperature dependence of the storage modulus (E′) for SBS di‐ and tetrafunctional methacrylic monomer systems were carried out to determine the distribution of the monomers in the domains or phases of the SBS block copolymer, as well as the aggregation state of each system. The forces of attraction between the monomer and the phases or domains in the matrix (similar solubility parameters with appreciable dipole‐dipole and hydrogen bonding interactions) were determinant as for the monomer distribution. The influence of these structural factors on the kinetic parameters of the photoinitiated polymerization of di‐ and tetrafunctional methacrylic monomers in the SBS matrix was studied. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 163–168, 2005     

不规则等高单层厂房结构空间分析

本文对钢筋混凝土装配式不规则等高单层厂房结构的空间分析问题做了讨论,其中包括沿厂房横向及纵向的屋盖刚度、排架刚度、屋盖处的水平作用荷载,以及在水平荷载作用下的空间分析方法。提出空间分析矩阵解法及迭代解法,前者需要有较大容量的计算机,后者用袖珍计算机甚至于手算便可完成。本文最后附有数字计算例题。     

n维空间二次特征值问题的分解定理

n 自由度线性阻尼振动系统的二次特征值问题,一般是在2n 维空间求得复数精确解,或在小阻尼、弱非比例阻尼情况下,在 n 维空间求得近似解.本文提出并证明了一个分解定理,即在一定条件下,n 维空间二次特征值问题可化为 n 维空间两个普通特征值问题,用标准算法求得精确解,大大降低了解题难度,简化了计算方法,节约了计算时间。     

复杂化学反应动力学参数的估算

复杂化学反应动力学参数估值计算常具有一些特殊困难性。本文着重讨论了采用Marquardt方法估计动力学参数时遇到的一些特殊问题,其中包括:(1) 阻尼矩阵及阻尼因子对计算过程的影响;(2) Jacobi矩阵的快速计算。结合上述讨论,本文提出了快速、稳定的计算策略。