Biodegradability of chlorinated anilines in waters

Objective To identify the bacteria tolerating chlorinated anilines and to study the biodegradability of o-chloroaniline and its coexistent compounds. Methods Microbial community of complex bacteria was identified by plate culture observation techniques and Gram stain method. Bacterial growth inhibition test was used to determine the tolerance of complex bacteria to toxicant. Biodegradability of chlorinated anilines was determined using domesticated complex bacteria as an inoculum by shaking-flask test. Results The complex bacteria were identified,consisting of Xanthomonas,Bacillus alcaligenes,Acinetobacter,Pseudomonas,and Actinomycetaceae nocardia. The obtained complex bacteria were more tolerant to o-chloroaniline than mixture bacteria in natural river waters. The effects of exposure concentration and inoculum size on the biodegradability of o-chloroaniline were analyzed,and the biodegradation characteristics of single o-chloroaniline and 2,4-dichloroaniline were compared with the coexistent compounds. Conclusion The biodegradation rates can be improved by decreasing concentration of compounds and increasing inoculum size of complex bacteria. When o-chloroaniline coexists with aniline,the latter is biodegraded prior to the former,and as a consequence the metabolic efficiency of o-chloroaniline is improved with the increase of aniline concentration. Meanwhile,when o-chloroaniline coexists with 2,4-dichloroaniline,the metabolic efficiency of 2,4-dichloroaniline is markedly improved.     

聚内酯类生物降解性高分子微球可注射细胞支架

目的:用于组织工程化软骨、骨、脂肪等修复重建和整形用的可注射细胞支架.方法:以聚丙交酯(PLLA)、聚丙交酯/聚乙二醇共聚物(PLE),以及聚己内酯/聚乙二醇/聚丙交酯共聚物(PCEL)等聚内酯类生物降解高分子为基材,采用乳液-溶剂挥发法制成微米级大小、具有一定形态结构的微球.结果:聚内酯材料的组成对微球的形态结构有重要影响,微球的孔结构和稳定剂种类对微球的细胞亲和性有重要影响;含聚乙二醇成分的聚内酯材料可以形成呈多孔结构的微球,且以明胶为稳定剂制备的微球细胞亲和性更好.结论:聚内酯类生物降解高分子微球具有可注射性和良好的细胞亲和性,是一类具有应用前景的可注射细胞支架.     

丙二醇/反丁烯二酰氯缩聚物复合材料生物相容性及体内降解实验研究

目的：研究丙二醇／反丁烯二酰氯缩聚物复合材料(poly(propylene fumarate，PPF)的生物相容性及生物降解性，并探讨其体内降解机制。方法：每组10个试件，分5组随机分别植入10只Wistar大鼠背部皮下，每组并设2只空白对照。于术后1，3，5，8，12周取材料周围软组织包膜、大鼠肝、肾进行组织病理学切片检查。结果：植入部位在初期有轻度炎症反应；5周后基本消失，未见多核巨细胞积聚现象；12周时材料保持形态完整，但强度明显下降。结论：PPF复合材料具有良好的生物相容性、较适宜的降解性能，是一种有前途的骨缺损修复材料。     

Histological Comparison of New Biodegradable Magnesium-Based Implants for Maxillofacial Applications

Background

A variety of materials have been used for bone augmentation, distraction osteotomy, and in post-cancer patients following tumor removal. However, a temporary metal implant that would resorb after successful treatment is a new concept. Magnesium was suggested as a suitable material for these purposes because it is biocompatible, has better mechanical properties than titanium, and stimulates new bone formation. This study evaluates histological appearance of magnesium-based implants and the surrounding bone.

Materials and Methods

Three magnesium-based biomaterials were tested in a rabbit bone defect model: magnesium–hydroxyapatite (Mg–HA), W4 (96 % magnesium, 4 % yttrium), and pure magnesium (pure Mg). Animals were sacrificed after 6 and 12 weeks and the samples were analyzed histologically and histomorphometrically.

Results

Mg–HA had the highest mean amount of tartrate-resistant acid phosphatase (TRAP) positive cells at the implantation site of all groups. It had shown the fastest degradation rate already at 6 weeks but the least amount of new bone formation. New bone was seen forming in direct contact with pure Mg and W4. The mean gas volume was highest in W4 compared to pure Mg and Mg–HA but this difference was not statistically significant. W4 had the lowest mean number of TRAP-positive cells of all materials.

Conclusion

Pure Mg and W4 were shown to be the most promising materials in this study in respect to the bone response to the implant material. They could be used for screws and plates in bone augmentation procedures.     

聚乳酸及其共聚物在生物医学领域中的应用

本文介绍了聚乳酸及其共聚物在医用缝合线、药物控制释放、组织工程材料、骨科材料、眼科植入材料等生物医药领域的应用,并对其在生物医学领域的应用前景进行展望。     

Amine-modified hyperbranched polyesters as non-toxic, biodegradable gene delivery systems

For chronic non-viral gene therapy, biodegradable carriers with low cytotoxicity are essential. To create a series of non-toxic and biodegradable gene carriers, hyperbranched polymers based on 2,2-bis-(methylol)propionic acid (bis-MPA); (Boltorn H^®) were modified by introducing tertiary amines. The terminal OH groups were modified with diethylaminopropylamine (DEAPA) by carbonyldiimidazole (CDI) chemistry. The resulting polymers were characterized by ¹H, ¹³C NMR, IR and GPC. Degradability and degradation rate were investigated with respect to the degree of amine substitution. The toxicity of all hyperbranched polyesters was generally very low compared to polyethyleneimine (PEI). Measurements of size and zeta potential showed that small nano-complexes with a positive zeta potential were formed. Dependency of the degree of amine substitution on interaction with DNA was studied by agarose gel retardation assay and ethidium bromide exclusion assay. Influence of the amine substitution on transfection efficiency of the different polymers demonstrated that a certain amine substitution degree was required to achieve transfection efficiency. These carriers provide degradability, very low toxicity and the ability to transfect cells which can be influenced by the degree of amine substitution.     

心血管可降解金属材料的研究进展

着重介绍了治疗心血管疾病中开发、研究金属类可降解材料的重要性，通过国内外研究可降解心血管材料所出现的问题进行了综述。特别对镁和纯铁的理化性质、生物相容性、耐腐蚀性能进行了比较和分析，论证了研制可降解金属材料的可能性。研究证明：对医用金属表面进行气体注入或稀土金属注入能在一定程度上提高金属在体内的抗蚀能力，通过合理的注入工艺和控制注入离子在金属中的分布密度、存在状态、注入深度，将可能有效的控制金属离子释放速率，这为研究和开发可降解心血管金属材料提供一条有效途径。     

生物可降解聚合材料聚羟基乙酸

聚羟基乙酸是一种简单的聚酯,它具有优异的可生物降解性和生物相容性,是一类较重要的医用 高分子材料。本文综述了聚羟基乙酸的一些性能的特点,制备方法及其应用。     

沈阳市源分类有机生活垃圾堆肥研究

阐述了城市有机生活垃圾源分类的重要性,同时对源分类城市有机生活垃圾进行两组不同物料配比的堆肥实验,在堆肥周期内对堆体的重要影响参数(水分、有机分、灰分、堆体温度、pH、堆体质量等)进行了测定,最后根据实验数据分析堆肥实验的影响因素并得出结论:(1)沈阳市生活垃圾含水率偏高不利于直接进行堆肥,添加秸秆作为填充剂进行堆肥是可行的;(2)沈阳市城市生活有机垃圾和秸秆混合后进行为期21 d堆肥处理,其堆肥最终生物降解率为60%～74%.其物料的含水率对生物降解率有较大的影响.     

自由基官能化聚合合成主链挂嘧啶碱基的聚合物

以合成的三种嘧啶衍生物为单体,通过加入能在自由基作用下开环异构的乙烯酮缩醛类进行了酯基封端、酯基嵌入的官能化聚合反应,对所得聚合物的生物降解性进行了一定程度的探查。