可降解聚氨酯型组织工程多孔支架材料的制备

本文在可降解型聚氨酯分子设计,聚氨酯型组织工程支架制备方法,可降解聚氨酯多孔支架的生物学性能及可降解聚氨酯多孔支架在组织工程中的应用等几个方面对可降解聚氨酯型组织工程支架的最新研究进展作了综述。重点讨论了静电纺丝、冷冻干燥、相分离等几种聚氨酯多孔支架制备方法以及聚氨酯型组织工程支架的生物降解性质、生长因子嵌入、生物力学性能、生物相容性等生物学性能。目前的研究表明通过聚氨酯分子设计与各种支架制备方法结合可制得满足各种生物学性能的支架材料且这类材料已被证实在血管、软骨、硬质骨等各类组织工程中有重要的应用价值。但如何进一步提高聚氨酯支架材料的力学强度以使其能更好地与硬组织的力学性能相匹配以及如何降低或消除聚氨酯对人体的毒性仍是需要进一步研究的问题。     

介入治疗用非血管可降解支架的研究进展

介入治疗是介于外科和内科治疗之间的新兴治疗方法,其中用于胆管、食管和气管等官腔的支架属于非血管介入治疗。非血管可降解支架与官腔具有良好的生物相容性,并且支架置入人体后,可以在一定时间内降解,转化为对人体无害的小分子排除体外。本文综述了介入治疗用非血管可降解支架的研究进展,重点介绍了非血管可降解支架的材料选择,外形设计,支架工艺(包括支架成型,覆膜改性,载药处理),性能测试(包括物理性能,力学性能,生物相容性,降解性能等)及临床应用进展。     

骨组织工程支架材料研究进展*

骨在组织工程中得到了非常广泛、深入的研究.支架材料与许多可降解材料一起也在进行探索性研究.用于骨组织工程的生物材料可以是三维多孔的刚硬材料,也可以是可注射材料.本文从聚合物角度综述了骨组织工程对支架材料的基本要求,用于骨组织工程的可降解生物材料、支架材料的设计和制备技术以及支架材料的表面修饰等方面的研究进展.     

组织工程用可生物降解聚合物多孔支架制备方法研究进展

可生物降解高分子多孔支架已广泛用作各种再生新组织模板,组织工程要求支架要有着良好的相互连通、高度开放的多孔结构,以实现细胞的增殖和分化。因此,如何把材料加工成满足生物体要求的结构至关重要。本文对最近几年组织工程用高孔隙率三维支架的制备方法进行了综述,并指出了各种方法的优缺点,展望了可降解高分子支架制备方法的发展前景。     

可降解聚酯多孔支架的常温模压成型

可降解聚酯多孔支架的常温模压成型;组织工程;多孔支架;可降解聚合物;聚ε-己内酯;聚合物加工     

《化学通报》网络版(Chemistry Online)2001年11月论文摘要

[Ｗ 0 1 0 98]聚羟基酯与骨组织工程Ｐｏｌｙ(α ｈｙｄｒｏｘｙｅｓｔｅｒ)ａｎｄＢｏｎｅＴｉｓｓｕｅＥｎｇｉｎｅｅｒｉｎｇ毛津淑　姚康德 (天津大学材料科学与工程学院　天津　 30 0 0 72 )组织工程的发展 ,对作为人工细胞外基质 (ＥＣＭ)的生物材料提出了挑战。本文阐述了理想骨再生组织工程用生物可降解支架的研制要求 ,重点介绍了聚羟基酯类聚合物 ,作为生物可降解支架原材料的优缺点和加工方法 ,强调了在其表面进行相应的仿生修饰 ,从而实现人工ＥＣＭ智能化。因此 ,以聚乳酸类可降解生物材料为主要成分的 ,有利于成骨细胞粘附 …     

多孔脂肪族聚酯组织工程支架的制备方法及改进

生物可降解人工合成脂肪族聚酯类聚合物支架已广泛应用于组织工程中,人们开发了多种方法制备多孔PLLA、PGA及其共聚物支架,并通过对这些方法的改进或多种方法的结合提高孔隙率,改善孔结构。本文介绍了这些制备方法及其改进措施的研究进展。     

医用高分子材料降解的原位探测方法

可降解高分子材料在骨科内固定、药物缓控释载体、组织工程支架、心血管支架等领域均有重要应用。为使材料的降解速率、力学性能与实际应用之间相匹配,需要对材料的降解行为有清晰的了解。早期对材料降解行为的研究主要采取定期取样测质量变化等方法,需消耗大量的样品和动物。为解决这个问题,一些新型成像技术被用于原位探测材料的降解行为,从而实现对同一个样品的连续监测。本文综述了近年来采用原位法研究可降解高分子材料降解行为的进展情况,侧重荧光成像法、光声及超声成像法和电化学方法。     

基于可降解聚合物的纺织技术在组织工程支架中的应用

近年来,随着再生医学的发展,组织工程技术再造人体组织器官被广泛的关注和研究.其中组织工程支架对于构建组织非常重要,其结构性质严重影响着再生组织的形态和性能.本文主要针对人工可降解材料,综述近年来基于纺织技术的组织工程支架的设计成型方法,并讨论不同成型工艺的支架性能及用途的差异.在用于不同部位的组织工程支架设计中,针织、机织、编织3种纺织手段可以控制纤维集合体的三维微孔结构和力学性能,在调控细胞活性和组织再生方面有至关重要的作用,显示出不同且不可相互替代的用途.纺织技术拓宽了人工可降解高分子材料在组织工程上的应用,通过材料的选择及结构的设计能够制备出力学、生物性能满足临床使用的支架,对推动组织工程临床化进程有重要意义.     

生物可降解医用聚氨酯及其应用

生物可降解医用聚氨酯由于其优良的生物相容性、降解性、功能化修饰和力学性能可调控等优点,逐渐引起研究者的关注,尤其在药物传递和组织工程支架等方面可望具有广阔的应用前景。结合本课题组开展的工作,本文综述了生物可降解医用聚氨酯材料在结构、功能化设计及医学应用上的研究进展,并展望了其在医学材料中的发展前景。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Investigation of Kinetics of Solid-Phase Synthesis of Lithium Orthosilicate

The kinetics of the interaction between lithium carbonate and silica with various degrees of dispersion was investigated by TG and DTA methods. It was found that the utilization of pyrogenic silica with a specific surface area of about 300 m²g^-1 instead of aerosil with one of 175 m²g^-1 leads to an increase of the reaction rate between lithium carbonate and silica, which depends on the formation and growth of lithium orthosilicate crystals in the first stage, and is conditioned by the diffusion of lithium and oxygen ions through the lithium orthosilicate layer formed at temperatures above 800 K. This supposition is supported by the kinetic analysis results obtained with the use of the different models. The optimal regime of heating is recommended. This revised version was published online in July 2006 with corrections to the Cover Date.     

小环化合物中饱和碳质子化学位移的计算

小环化合物由于其张力、构型、构象和各向异性效应等原因,环碳上质子化学位移缺乏规律性,难以预测,对此作者曾提出一种近似算法。本文根据303种小环化合物中饱和碳质子的化学位移实验数据,将适于计算这类质子化学位移的公式表述为:     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。