Stimulatory effects of tannins and cholic acid on tryptic hydrolysis of proteins: Ecological implications

The biochemical basis for considering tannins as digestion inhibitors has been reexamined. Both stimulatory and inhibitory effects of tannins on tryptic hydrolysis are reported. We show how stimulation may result from tannin-induced structural changes in the substrate protein, effectively denaturing it. The surfactant and bile constituent cholic acid also produced similar stimulatory effects. These results have considerable implications for normal digestive physiology as well as for the impact of tannins on argicultural and natural herbivore populations.     

Effect of algal extracellular polymer substances on UF membrane fouling

Low-pressure membrane processes, such as ultrafiltration (UF), are effective for treating algae-laden eutrophic source waters. However, fouling caused by algae excreted organics can be a major obstacle to the smooth operation of membrane processes. In this study, three algae species, with a similar cell size and shape, but a different amount of extracellular polymeric substances (EPS), were selected. The characteristics of the bound EPS, including its amount and constituents, mainly polysaccharide and protein, were analyzed. Cell suspensions were filtered through a dead-end stirred cell with a regenerated cellulose UF membrane. Based on the observations of permeate flux decline at higher transmembrane pressure (TMP) and critical flux values, it can be concluded that algae cell EPS do affect membrane fouling, and the constituents of EPS may also play a role.     

Luminescence properties of the Langmuir-Blodgett film of terbium(III) stearoylanthranilate

Terbium(III) stearoylanthranilate has been prepared as a high property Z-type Langmuir-Blodgett (LB) film on various substrates by a vertical transfer process. The UV-visible absorption spectra and the low angle X-ray diffraction peaks have been collected in order to investigate the molecular arrangement and aggregation in the LB films. The average molecular orientation in multilayer stacking was determined by Attenuated Total Reflection Spectroscopy. The influence of the chemical environment of terbium within the LB films on the luminescence properties has been discussed.     

母液中高浓度有机物对甲酸钠生产的影响及应对措施

甲酸钠为季戊四醇装置的副产品,生产中存在的主要问题是蒸汽的消耗高,甲酸钠产品含量偏低,有机物含量高。究其根本原因是甲酸钠母液中有机物浓度升高所致。本文针对系统有机物浓度高对甲酸钠生产的影响进行了分析探讨,同时提出了降低甲酸钠母液有机物浓度的方法。     

甲基多巴中有关物质的液相色谱法测定研究

采用HPLC法测定甲基多巴中3-甲氧基甲基多巴及其它有关物质的含量,并与药典中的TLC法进行对比.色谱条件为:色谱柱:phenomenex LUNA C18分析柱(4.6 mm×250 mm,5um),流动相:乙腈-2.0%磷酸氢二钠水溶液,加入磷酸调节pH至5.0(10∶90),流速:1 mL/min,检测波长:280 nm,进样量:20μL.该方法中甲基多巴和3-甲氧基甲基多巴及氨基丙腈分离度良好,线性范围分别为0.002~0.1μg(r=0.999 97),检测限:1 ng;0.008~0.2μg(r=0.999 8),检测限:2 ng.本法简单、专属,能有效快速地控制产品质量.     

巢湖叶绿素a与环境因子耦合效应的多元分析

针对巢湖西半湖富营养化情况,利用实测资料,通过相关分析和多元逐步回归统计,分析环境多元耦合效应与水体叶绿素a质量浓度之间的关系,找出显著环境因子,建立多元逐步回归方程,预测叶绿素a质量浓度变化.结果表明,巢湖西半湖叶绿素a质量浓度夏季高冬季低,其变化受多个环境因子共同影响,相关性较显著的为气温、水位、CODMn等.在各...     

高层建筑层间位移控制的探讨

探讨了层间位移的组成及其与层位移差的相互关系,介绍了各国规范对于层间位移控制的规定,以及控制层间位移的一些方法,最后得出一些结论供大家讨论。     

不良文化对大学生的影响与对策

不良文化已经影响了大学生的健康成长.对不良文化的防范包括整治校园周边环境,树立良好的社会风气,加强传统道德、传统文化的教育,发挥校园文化的主导作用等.     

纳米二氧化钛胶体对脱墨浆中DCS絮聚去除的GC-MS研究

采用GC-MS表征絮聚前后DCS组分变化的方法研究了纳米TiO2胶体对脱墨浆中DCS絮聚去除的机理.结果表明,该脱墨浆中DCS可硅烷化主要组分为树脂酸、脂肪酸、苯二甲酸酯类物质、2,2-双（4-羟苯基）丙烷和甾醇类等物质;纳米Ti O2胶体对上述多数组分有较强的絮聚去除能力,去除机理主要为“桥连絮聚”作用,且去除效果随组分分子极性增大而增强,随分子结构的位阻屏蔽作用增强而减弱.     

异养菌与自养菌对好氧颗粒污泥稳定性的影响

研究了异养菌和自养菌颗粒污泥的特性：与异养菌相比,自养菌颗粒污泥粒径小、密度大、胞外多聚物（EPS）含量高但强度小。通过对粒径、EPS等特性与密度的变化规律分析,研究发现,自养菌颗粒污泥的粒径与密实度呈现出一致性,颗粒趋于稳定;而异养菌颗粒污泥粒径成长同时伴随着密度减小,粒径与密实度呈现不一致性,颗粒容易解体。颗粒强度的分析结果表明：在自养菌系统中EPS与孔隙率能够达到动态平衡是其长期维持稳定的主要原因,而异养菌中粒径与孔隙率无法达到平衡,操作条件无法控制高强度丝状菌的繁殖是其不稳定的主要因素。