取代苯胺及苯酚类化合物定量结构-生物降解相关性(QSBR)研究

采用MOPAC－AM1法计算了15种取代苯分子的三种量化参数,用QSAR程序计算了两种物化参数及一种电性参数,结合德华半径RW,对log Kb进行了回归分析,得到如下最佳方程：log Kb=0.329 pK-10.48kw-12.995应用所得QSBR模式预测了15种有机物的生物降解性,并分析了降解机理。     

聚碳酸亚丙亚乙酯的合成和生物降解

由ＣＯ２和环氧丙烷的催化共聚制备了聚碳酸亚雨酯（ＰＰＣ），向ＰＰＣ引入环氧乙烷结构单元得到聚碳酸亚西亚乙酯（ＰＰＥＣ），用１ＨＮＭＲ等进行了结构表征，并用土埋法进行了生物降解性能的测定，结果表明ＰＰＣ仅在分子量很低时才具备显著的生物降解性能；而ＰＰＥＣ的生物降解速度高于分子量相近的ＰＰＣ．此外，土埋三月后共聚物的组成和分子量都保持基本不变，表明实验条件下生物降解主要在聚合物的表面进行．     

可生物降解的高分子类型,合成和应用

综述了生物降解高分子的定义，实现生物降妥的主要方法和生物降解高分子主要类别，以及它们在生物医学领域及环保事业等方面的重要用途和意义。阐明了影响生物降解速度的主要因素，对控制，调节生物降解速度的订研究动态进行了介绍。     

生物降解性聚酯

本文阐述了生物降解性聚酯的主要产品，生物降解性聚酯的降解机理及生物降解性聚合物的存在问题和研究方向．     

芳香族化合物生物降解性的QSBR研究

分别采用线性基团贡献法和人工神经网络法对芳香族化合物的生物降解最大去除率QTOD进行QSBR研究。得到不同基团对生物降解性的贡献顺序为 :C6H5>COOH >OH >CO >CH3 >C1 >NH2>NO2 。线性基团贡献法对于训练组和测试组的预测正确率分别为 86%和 80 % ,总的预测正确率达85 % ;而人工神经网络法的预测正确率分别为 94%、80 %和 92 %。结果表明 ,线性基团贡献法和神经网络法的预测效果均很好 ,而神经网络法的预测更精确。     

废水中有机污染物降解机理的研究方法

我国废水排放总量较大,且废水中含有的多种有机污染物一直是人类生命健康的潜在威胁,因此对废水处理的研究必不可少,而理解废水中有机污染物的降解机理是处理各种废水的基础.本综述概述了国内外针对各种有机污染物降解机理的研究方法,主要包括实验手段和计算模拟两大类.实验手段中主要采用光谱分析技术检测有机污染物降解过程中生成的中间产物,进而推测有机污染物的降解路径.但是由于实验条件和实验方法的不同,对于同种物质的降解机理研究,不同的实验结果存在着争议.基于量子化学计算、定量构效关系模型（QSAR）、定量结构-生物降解性能关系模型（QSBR）、统计分子碎化模型（SMF）等计算模拟方法为有机污染物降解机理的研究提供了新的方法.将实验手段和计算模拟有机结合起来,可为有机污染物的降解机理研究提供参考和指导.     

脂肪族聚酯及共聚酯的生物降解性研究

以酯交换法或直接缩聚法合成了一系列脂肪族聚酯，经二异氰酸酯(HDI)扩链得到含氨酯键的聚酯及共聚酯，用DSC、X射线衍射等分析表征了聚酯及共聚物的结构和性能。用土埋试验、CO2释放试验和黑曲霉降解试验着重研究了这些聚合物的生物降解性，详细讨论了聚酯结构、组成及聚酯分子量对生物降解性的影响。     

可生物降解交联聚合物的研究进展

交联聚合物具有稳定的三维网络结构,可以提高药物缓释载体的尺寸稳定性。本文综述了可生物降解交联聚合物的研究进展,主要介绍了可生物降解交联聚合物的制备方法,包括交联剂交联、辐照交联、光致交联以及过氧化物交联在制备可生物降解交联聚合物中的应用,详细介绍了交联剂的种类及结构对交联效果的影响、交联后聚合物性能的变化等。最后总结了可生物降解交联聚合物在组织工程支架、药物缓释材料、神经再生修复材料以及形状记忆材料等生物医用领域的应用。     

偶氮染料分子的电子结构与生物降解活性(Ⅰ)——电荷分布对偶氮键还原裂解的影响

用量子化学MNDO方法计算了不同结构类型的偶氮染料分子的电子结构.与厌氧活性污泥对偶氮双键生物降解实验结果对照分析后发现,分子电子结构中,电荷分布的对称性对偶氮键生物降解活性有重要影响.并通过LUMO_lp(具有反应部位氮原子孤电子对特征的最低空轨道)及分子偶极矩阐述了电子结构与生物降解活性的关系.     

多孔β－TCP生物降解陶瓷的拉曼光谱

求文研究了多孔Ｂ－ＴＣＰ生物降解陶瓷及其粘结剂的拉王光谱。参照各种磷酸盐及磷酸盐玻璃的拉曼光谱，对生物降解陶瓷的拉曼特征频率进行了经验式的归属和指认。实验结果表明，生物降解陶瓷以β－Ｃａ３（ＰＯ４）２（β－ＴＣＰ）为主晶相，当粘结剂含量增加时，生物降解陶瓷中出现明显的Ｃａ４Ｐ２Ｏ９９和Ｃａ２Ｐ２Ｏ７，晶相和其他非晶相，其含量随粘结剂量增加而增加，并呈现一种多孔的网络结构。     

External validation of structure-biodegradation relationship (SBR) models for predicting the biodegradability of xenobiotics

Biodegradation is an important mechanism for eliminating xenobiotics by biotransforming them into simple organic and inorganic products. Faced with the ever growing number of chemicals available on the market, structure–biodegradation relationship (SBR) and quantitative structure–biodegradation relationship (QSBR) models are increasingly used as surrogates of the biodegradation tests. Such models have great potential for a quick and cheap estimation of the biodegradation potential of chemicals. The Estimation Programs Interface (EPI) Suite? includes different models for predicting the potential aerobic biodegradability of organic substances. They are based on different endpoints, methodologies and/or statistical approaches. Among them, Biowin 5 and 6 appeared the most robust, being derived from the largest biodegradation database with results obtained only from the Ministry of International Trade and Industry (MITI) test. The aim of this study was to assess the predictive performances of these two models from a set of 356 chemicals extracted from notification dossiers including compatible biodegradation data. Another set of molecules with no more than four carbon atoms and substituted by various heteroatoms and/or functional groups was also embodied in the validation exercise. Comparisons were made with the predictions obtained with START (Structural Alerts for Reactivity in Toxtree). Biowin 5 and Biowin 6 gave satisfactorily prediction results except for the prediction of readily degradable chemicals. A consensus model built with Biowin 1 allowed the diminution of this tendency.     

QSBR Study on the Anaerobic Biodegradation of Chlorophenols

1 INTRODUCTION Chlorophenols (CPs) have been widely applied in such industries[1] as wood preservative, antitrust, bactericide and herbicide since 1930s. Due to the existence of phenol ring structure and chloro-atom, chlorophenols have strong toxicity and high anti- degradation ability. Previous reports show that[2, 3] chlorophenols are difficult to oxidize under aerobic condition, whereas anaerobic biological treatment can effectively reduce the toxicity towards microor- ganism so as to …     

Quantitative prediction of biodegradability,metabolite distribution and toxicity of stable metabolites

An evaluation of the capability of organic chemicals to mineralize is an important factor to consider when assessing their fate in the environment. Microbial degradation can convert a toxic chemical into an innocuous one, and vice versa , or alter the toxicity of a chemical. Moreover, primary biodegradation can convert chemicals into stable products that can be difficult to mineralize. In this paper, we present some new results obtained on the basis of a recently developed probabilistic approach to modeling biodegradation based on microbial transformation pathways. The metabolic transformations and their hierarchy were calibrated by making use of the ready biodegradability data from the MITI-I test and expert knowledge for the most probable transformation pathways. A model was developed and integrated into an expert software system named CATABOL that is able to predict the probability of biodegradation of organic chemicals directly from their structure. CATABOL simulates the effects of microbial enzyme systems, generates the most plausible transformation pathways, and quantitatively predicts the persistence and toxicity of the biodegradation products. A subset of 300 organic chemicals were selected from Canada's Domestic Substances List and subjected to CATABOL to compare predicted properties of the parent chemicals with their respective first stable metabolite. The results show that most of the stable metabolites have a lower acute toxicity to fish and a lower bioaccumulation potential compared to the parent chemicals. In contrast, the metabolites appear to be generally more estrogenic than the parent chemicals.     

Quantitative prediction of biodegradability,metabolite distribution and toxicity of stable metabolites

An evaluation of the capability of organic chemicals to mineralize is an important factor to consider when assessing their fate in the environment. Microbial degradation can convert a toxic chemical into an innocuous one, and vice versa, or alter the toxicity of a chemical. Moreover, primary biodegradation can convert chemicals into stable products that can be difficult to mineralize. In this paper, we present some new results obtained on the basis of a recently developed probabilistic approach to modeling biodegradation based on microbial transformation pathways. The metabolic transformations and their hierarchy were calibrated by making use of the ready biodegradability data from the MITI-I test and expert knowledge for the most probable transformation pathways. A model was developed and integrated into an expert software system named CATABOL that is able to predict the probability of biodegradation of organic chemicals directly from their structure. CATABOL simulates the effects of microbial enzyme systems, generates the most plausible transformation pathways, and quantitatively predicts the persistence and toxicity of the biodegradation products. A subset of 300 organic chemicals were selected from Canada's Domestic Substances List and subjected to CATABOL to compare predicted properties of the parent chemicals with their respective first stable metabolite. The results show that most of the stable metabolites have a lower acute toxicity to fish and a lower bioaccumulation potential compared to the parent chemicals. In contrast, the metabolites appear to be generally more estrogenic than the parent chemicals.     

A critical review and evaluation of bioproduction of organic chemicals

Dependence on petroleum as the primary feedstock for production of chemicals cannot continue indefinitely. Bioconversion could provide an alternate route to production of organic chemicals. A wide range of commodity chemicals and potentially new chemicals can be produced via bioconversion of biomass. However, before large-scale bioproduction of organic chemicals becomes a reality, issues related to economics, feedstock availability, environment, and energy requirements must be addressed. In this paper, these issues are discussed. and promising potential candidates for bioproduction are identified. Research needs are briefly addressed.

     

Polymer nanotubes toward gelating organic chemicals

Crosslinked polymer nanotubes are large scale synthesized. The method is based on fast cationic polymerization using immiscible initiator nanodroplets. Nanoporous network processed from the nanotubes is superhydrophobic, which can absorb all the tested organic chemicals forming robust gels. The nanotubes are promising in the collection of spilled organic chemicals, detoxification and water treatment.     

木质生物质转化高附加值化学品

本文阐述了木质生物质转化为主要化学品的类型及其转化途径,提出了从木质生物质转化高附加值化学品的新思路.木质生物质通过一定的降解或分解途径,可产生很多有重要价值的有机小分子化合物,这些有机小分子化合物有葡萄糖、木糖、苯丙烷单体及二聚体,气态小分子如CH4和CO,液态小分子如有机酸、醛、醇,重要基础平台化合物糠醛、乙酰丙酸、木糖醇、乙醇等.通过这些小分子有机化合物的转化,可产生替代石油基产品的高附加值化学品,对可持续发展具有重要意义.