β-环糊精/TiO2复合光催化剂制备及光催化性能探讨

研究用硅烷偶联剂KH560做交联剂,以β-环糊精(β-CD)对TiO2固体表面进行改性,制备β-CD/TiO2复合材料.通过钛含量测定、红外和热重分析对β-CD/TiO2复合材料进行了表征.以甲基橙溶液为研究对象,分别考察了β-CD/TiO2复合材料和纯TiO2对甲基橙的光催化降解能力.结果表明：制得的β-CD/TiO...     

壳聚糖固定化酶载体小球的研究及制备方法的改进

比较了不同粘均相对分子质量壳聚糖(50×104,100×104,200×104)的成球情况及壳聚糖相对分子质量对固定化酶活力、酶活性回收率的影响,确定了50×104的壳聚糖为最适固定化β-半乳糖苷酶载体. 自设计方法制备了毫米级壳聚糖小球,较传统方法更加简单、快速. 湿润壳聚糖小球直接干燥和采用体积分数为30%的甘油处理后干燥对比实验表明,后者能够保持小球湿态时的结构,既保证了酶的固定化效果,又有利于载体的工业储存.     

共形平坦的切触度量流形上关于其半对称度量联络的一些结果

利用共形平坦的切触度量流形上的＊-Ricci算子Ric^＊的表达式,得到了Ric^＊和其半对称度量联络 的Ric^＊之间的关系,还给出（α,β）型近trans—Sasakian流形关于半对称度量联络 是（α,β＋1）型的结果。     

巨大芽孢杆菌AP25内切葡聚糖酶基因的克隆及序列测定

从土壤中分离到一株产纤维素酶的巨大芽孢杆菌AP25,经羧甲基纤维素平板检测,该菌可产生葡聚糖内切酶。根据GenBank登录的β-1,4内切葡聚糖酶基因（DQ782954．1,M28332．1,AY859492．1）的同源性序列,利用PCR方法克隆到该酶的基因,并对其进行测序。测序结果显示其全长为1500bp,推测其含499个氨基酸。与GenBank中的已知葡聚糖内切酶相比较,发现该酶的氨基酸序列与Bacillus subtilis的β-1,4内切葡聚糖酶基因同源性达到达94％。     

Aβ16—22聚集及海藻糖抑制其聚集过程的毛细管电泳检测

淀粉质β（amyloidp,Aβ）多肽是阿尔兹海默症（Alzheimer’Sdisease,AD）的致病蛋白,其疏水核心Aβ16—22具有重要的研究价值．以Aβ16—22为模型多肽,利用毛细管电泳检测方法,分析了Aβ16—22在水溶液和海藻糖溶液中的聚集过程．结果表明,毛细管电泳法不仅能够很好地分离Aβ16-22聚集过程中单体和部分聚体,实现对多肽聚集过程的快速鉴定和分析,同时也可检测海藻糖对Aβ16—22聚集的抑制作用．研究结果可为Aβ聚集抑制剂的高通量筛选和AD治疗中的快速诊断提供实验基础．     

苏丹Ⅰ替代番茄红素和β-胡萝卜素标准品的研究

番茄红素是一种具有多种生理功能的类胡萝卜素，由于含有数目众多的双键，极易发生氧化和顺反异构化，而在HPLC检测中需要使用番茄红素标准品以确定保留时间和计算样品中番茄红素的含量，但番茄红素标准品价格昂贵，且本身稳定性差，不宜长期保存。文中根据苏丹Ⅰ在450nm处和番茄红素、β-胡萝卜素具有相同的吸收特性，研究用苏丹Ⅰ替代番茄红素和β-胡萝卜素标准品，检测误差不超过2%；说明苏丹Ⅰ可用作标品进行番茄红素和β-胡萝卜素的检测。得到了番茄红素和β-胡萝卜素的计算公式。     

Wnt/β-catenin信号途径在DDR和氧化应激中的作用

Wnt/β-catenin信号途径在调控基因表达与DNA损伤反应(DNA damage response,DDR)中具有重要作用.氧化应激是导致DNA损伤的主要原因,且可以影响Wnt信号.首先总结了Wnt/β-catenin信号途径和DDR,然后综述了Wnt/β-catenin信号途径在DDR和氧化应激中的作用及分子机制,以期为DNA修复缺陷性肿瘤提供更有效的治疗策略.     

外源性激素对中国对虾精巢发育和雌雄性比影响的初步研究

本文报道了分别投喂含有１７α－甲基睾丸酮和１７β－雌二醇两种激素饵料对中国对虾精巢发育和雌雄性比的影响。结果表明：１７α－甲基睾丸酮可促进精巢发育，加快精原细胞形成精细胞和精子的过程；而１７β－雌二醇的作用不明显。两种激素对中国对虾雌雄性比无影响（Ｐ＞０．０５）。     

Tensile deformation behavior of a solution-treated Ti-33Nb-4Sn alloy with a dual β and α" phases under cyclic loading-unloading

The cyclical tensile deformation behavior of a solution-treated(ST) Ti-33Nb-4Sn alloy with a dual β and α "phases was investigated in this study.Experimental results indicated that the ST Ti-33Nb-4Sn alloy exhibited different deformation behavior during two different loading-unloading cycles,and that the deformation behavior was closely related to the characteristics of stress-induced martensitic(SIM) transformation,mainly including the extent and the reversibility of SIM transformation.During the first cycle,the extensive and incompletely reversible SIM transformation occurred,resulting in notable "double yielding" during loading and residual permanent strain after unloading.In the second cycle,however,a slight and reverse SIM transformation,together with pure elastic deformation,taken place concurrently,giving rise to a recoverable nonlinear deformation behavior.Our results also imply that by tailing the characteristics of SIM transformation,the Ti-based alloys with a mixture of α" and β phases might perform recoverable deformation and possess a promising potential for engineering applications.     

Enhanced urease inhibition activity of Ag nanomaterials capped with N-substituted methyl 5-acetamido-β-resorcylate

Medically, bacterial ureases are important virulent factors and are used for treatment of peptic ulcers and urinary tones. Reported urease inhibitors are associated with various side effects including antibiotic resistance as a major one. Still there is an urgent need to synthesize new urease inhibitors. In this context we have synthesized new urease inhibitor i.e. AgL that is composed of Ag nanomaterials capped with N-substituted methyl 5-acetamido-β-resorcylate(L). The conjugation of L to silver was confirmed through FTIR, UV–vis and TEM analysis.Bare silver nanomaterials(Ag) were also prepared. The stability of AgL nanostructures was determined against various parameters(temperature, high salt concentration, pH) and found to be stable. The in vitro antimicrobial(antibacterial, antifungal), enzyme inhibition(xanthine oxidase, urease, carbonic anhydrase, α-chymotrypsin,cholinesterase) and antioxidant activities of AgL were investigated and compared with Ag, L and standard drugs.In comparison to other bioactivities, AgL shows statistically enhanced selective enzyme inhibition activity against urease enzyme. Urease inhibition activity of AgL was significantly greater than standard drug(thiourea),L and Ag. On a per weight basis, AgL required about 11–18 times less amount of L for inhibition of urease enzyme.