溶液共混法制备高强度淀粉基完全生物降解塑料薄膜

利用一步溶液共混法，将预糊化的淀粉糊与PvA溶液共混，用乙二醛进行交联，制备淀粉／聚乙烯醇（PVA）完全生物降解塑料薄膜。研究不同乙二醛和甘油的用量对薄膜性能的影响。薄膜的力学性能、热性能和微观形态表征表明，淀粉／PvA体系具有较好的相容性和较高的力学性能，薄膜的拉伸强度和断裂伸长率分别可达到28．52MPa和307．5％。     

Modeling of batch phenol biodegradation in internal loop airlift bioreactor with gas recirculation by Candida tropicalis

A mathematical model for simulating the dynamic behaviors of batch phenol biodegradation processes in internal loop airlift bioreactor (ILAB) with gas recirculation using free cells of the yeast Candida tropicalis was established by coupling the fluid dynamic model and the mass balance model. Based on the coupling arithmetic, the program for evaluating batch phenol biodegradation processes was achieved. The predicted results of linear liquid velocities, gas holdups, linear gas velocities, cell and phenol concentration profiles in the riser and the downcomer of the ILAB with gas recirculation agreed very well with the corresponding experimental data, and the applicability and reliability of this proposed model were validated.     

固定化微生物细胞降解邻苯二甲酸二丁酯

The biodegradation of di-n-butyl phthalate （DBP） using immobilized microbial cells was carded out in an internal airlift loop reactor with ceramic honeycomb supports. A strain that is capable of degrading DBP was isolated from the activated sludge and identified as Bacillus sp. using 16S rDNA sequential analysis. Bacillus sp. could be rapidly attached onto the ceramic honeycomb supports. The immobilized cells could effectively degrade DBP in batch and continuous experiments. When the influent concentration of DBP was 50mg·L^-1, the effluent DBP reached less than lmg.L i with 6h hydraulic retention time （HRT） in continuous experiment. The immobilized microbial cells could grow and accumulate through the biodegradation of DBP, and the rate of degradation is accordingly increased. The possible pathway of DBP biodegradation using immobilized cells was tentatively proposed.     

PAHs代谢物对PAHs生物降解的影响作用

分别研究了芽胞杆菌CN2降解蒽产生的代谢物对蒽生物降解的影响和菲产生的代谢物对菲生物降解的影响.试验结果表明:(1)外加蒽(或菲)代谢物,对蒽(或菲)的降解均表现出促进作用.蒽156 h累计去除率可提高3.07%～6.10%,菲60 h累计去除率可提高13.14%～30.35%.(2)在芽胞杆菌CN2作用下,蒽(或菲)生物降解过程能够用一级动力学方程式较准确地描述,外加代谢物可以增大降解反应表观速率常数k值;从不同时段内蒽(或菲)的降解速率看,反应初期0～2 h内,外加代谢物对蒽(或菲)的降解速率提高最为明显,对蒽可提高0.281～1.20 mg/L·h,对菲可提高0.570～1.13 mg/L·h.(3)外加代谢物对蒽(或菲)降解液的pH值有缓冲作用,使降解液的pH值随降解时间下降趋势减缓.     

白腐菌Panus conchatus降解稻草木素机理研究──(一)低分子木素降解产物各组分的分离及特征

经白腐菌Panusconchatuss发酵15天的稻草用乙酸乙酯进行抽提可有效分离出生物作用后的低分子量木煮降解产物。利用这些低分子降解产物在酸碱度不同的介质以及不同的有机溶剂中的溶解度不同进一步分离、分级和提纯，获得酚类（LP），芳香酸类（LA1—4）以及中性物质三个组份。我们发现LP与LA是降解产物中的主要组份，它们的得率分别为51．1％和34．4％。如此高的LP得率是白腐菌P．conchatus降解稻草木素的重要特征。本文还利用红外光谱和核磁共振技术对LP和LA中最多的一个组份LA—1的可能化学结构特征进行剖析。     

关于木素生物降解酶类活力测定问题的讨论

由于木素结构和生物降解过程复杂多样，全面测定一个菌株的木素降解活力也比较困难，目前已发现三类主要参与木素降解的酶类（LIP、MnP、漆酶），但至今很少有国际上公认的酶活力测定方法，也未见到能把某一菌株木素降解酶类的活力与其在木质纤维材料中降解木素的能力定量关联的报导。本文综合评述了几类主要的木素降解酶类活力测定方法的作用机制和存在的问题，指出一个菌株的木素降解活力是由它的生理特性和总体代谢能力共同决定的，仅由一类或几类酶活力的表现水平难以对其作出确切的评价，从这个角度出发进行研究才能更客现他认识菌株的木素降解活力．     

Preparation and properties of β-tricalcium phosphate porous bioceramic

Porous β-tricalcium phosphate bioceramic (PTCP) has important roles in surgical implants because of good biocompatibility. But the low compressive strength of the ceramic limits its application. The preparation of PTCP was improved with the adjustment of the constituents and the sintering-process. A new type of PTCP material with high compressive strength was made. The compositions, microstructure and properties of PTCP were analyzed by TG-DSC, XRD, TEM, SEM and so on. The result indicates that stearic acid burns sufficiently and gives out carbon dioxide and water vapor when slowly heated between 200 ℃ and 400 ℃ so that the porous structure like coral in β-TCP bioceramic is formed. Through crystallization at 470 ℃ and 570 ℃, more CaO-P2O5 glass-cement is converted into crystallite-glass, which is beneficial for improving the compressive strength of β-TCP bioceramic.PTCP can form a support action in bone imperfect section with good solubility.     

Ferritin Protein Regulates the Degradation of Iron Oxide Nanoparticles

Proteins implicated in iron homeostasis are assumed to be also involved in the cellular processing of iron oxide nanoparticles. In this work, the role of an endogenous iron storage protein—namely the ferritin—is examined in the remediation and biodegradation of magnetic iron oxide nanoparticles. Previous in vivo studies suggest the intracellular transfer of the iron ions released during the degradation of nanoparticles to endogenous protein cages within lysosomal compartments. Here, the capacity of ferritin cages to accommodate and store the degradation products of nanoparticles is investigated in vitro in the physiological acidic environment of the lysosomes. Moreover, it is questioned whether ferritin proteins can play an active role in the degradation of the nanoparticles. The magnetic, colloidal, and structural follow‐up of iron oxide nanoparticles and proteins in lysosome‐like medium confirms the efficient remediation of potentially harmful iron ions generated by nanoparticles within ferritins. The presence of ferritins, however, delays the degradation of particles due to a complex colloidal behavior of the mixture in acidic medium. This study exemplifies the important implications of intracellular proteins in processes of degradation and metabolization of iron oxide nanoparticles.     

心脏补片的生物力学研究评述

细胞移植是心肌组织工程中治疗心肌梗死的一种潜在的治疗方法.心脏补片不仅是种子细胞的载体,还可抑制心脏的膨胀扩张,以促进种子细胞对梗死心肌组织的修复再生.心脏补片的研制已经成为基础与临床医学、材料科学和生物力学等的交叉热点.本文评述了心脏补片的生物力学研究现状,并就本领域今后值得关注的问题进行展望.     

N-十二烷基葡萄糖胺型表面活性剂的合成

以n(葡萄糖):n(十二胺)=1:1.3合成了中间体N-十二烷基葡萄糖亚胺。中间体在35～45℃,压力为3.5MPa,Raney-Ni作催化剂条件下高压催化加氢合成了N-十二烷基葡萄糖胺,纯化后产率为55.7%;中间体在氧化剂H2O2和缓冲剂NaHCO3存在下,N2环境0～5℃反应3h后,55℃无水条件下反应20h合成了硝酮类化合物N-氧自由基-N-十二烷基葡萄糖亚胺,纯化后产率为60.2%。通过IR,元素分析和1HNMR对产品和中间体进行了结构表征。测定了N-十二烷基葡萄糖胺和N-氧自由基-N-十二烷基葡萄糖亚胺对钙、镁离子的键合能力,分别为157.40mgCaO.g-1、252.30mgMgO.g-1和154.75mgCaO.g-1、283.4mgMgO.g-1。考察了两者的生物降解性能,在10d内降解度分别为96.1%、98.5%,达到了欧盟议会和欧盟委员会关于洗涤剂的(EC)No648/2004法规对表面活性剂生物降解性的要求,属于易降解表面活性剂。