天然石材上二氧化硅膜的制备

本文以正硅酸乙酯为原料,无水乙醇为溶剂,盐酸为催化剂,十六烷基三甲基溴化胺为模板剂,用溶胶—凝胶法在石材上制备一层纳米量级的SiO2薄膜.通过正交实验获得了制备SiO2膜的最优条件,并利用光学显微镜,X射线衍射仪等手段对膜进行了分析和表征.这层薄膜有望在石质文物的保护上得到应用.     

不同温度和操作压力下污泥浓度对重力出流式SMBR膜通量影响

采用重力出流式淹没式膜生物反应器（SMBR）处理模拟生活污水,研究了不同温度和操作压力下污泥浓度ρ对膜通量的影响。结果表明：操作压力为20kPa时,不同温度下膜通量随ρ的变化呈现相同趋势。当0．65g／L〈ρ〈2．7g／L时,膜通量随着ρ的增加而迅速衰减;当2．7g／L〈ρ〈8．36g／L时,ρ的变化对膜通量影响不大;当8．36g／L〈ρ〈12．6g/L时,膜通量随着ρ的增加呈缓慢衰减趋势。温度升高有利于增大膜通量。操作压力较高时（20～30kPa）,膜通量随ρ增加而减小的速率较快。操作压力较低时（10kPa）,ρ对膜通量的影响较小。建立了不同温度和操作压力下膜通量与ρ的数学模型。     

植物细胞膜H^＋-ATPase对环境因子和逆境胁迫的适应

植物细胞膜H^＋-ATPase是初级转运蛋白,它在养分离子跨膜运输、胞内pH调节、细胞伸长生长、气孔开闭,以及植物适应所处的环境与发育过程等生命活动中起着重要的作用。综述了植物细胞膜H^＋-ATPase在酶活性、基因表达水平以及蛋白水平等方面对不同环境因子及逆境胁迫的适应性;指出分离鉴定、信号传导H^＋-ATPase等将是进一步的研究方向。     

水稻缺铁胁迫条件下根部形态及电镜观察

为研究缺铁胁迫条件下植物的适应机制,首次使用植物凝胶培养方法对不同条件下的水稻根进行形态学观察,结果发现苗期水稻缺铁诱导的根毛和侧根明显增多,幼根周围有分泌物出现.进一步利用电镜制样技术和超薄切片技术在透射电子显微镜下观察两种处理的水稻根尖细胞中膜泡的分布和形态.发现缺铁培养的水稻根尖细胞中膜泡的个数较多,而且较明显.为水稻在适应缺铁胁迫下根部细胞内膜泡运输增强提供了证据.     

膜池砼表面缺陷处理据施与质量控制

针对某水资源利用工程在膜池施工过程中出现的砼表面缺陷,提出了具体的处理措施和质量控制方法。     

膜生物反应器（MBR）在污水处理中的应用

介绍了膜生物反应器的类型及其工艺特点,重点阐明了膜生物反应器在各种类型污水处理中的应用,并提出了今后的研究方向。     

混凝—微滤工艺的研究进展

综述了混凝—微滤在饮用水处理和工业废水处理中的应用情况,分析了膜污染的特征和膜清洗的方法,讨论了粒度分维在混凝—微滤工艺中的研究进展。     

Cell-penetrating peptides: tools for intracellular delivery of therapeutics

The main problem of therapeutic efficiency lies in the crossing of cellular membranes. Therefore, significant effort is being made to develop agents which can cross these barriers and deliver therapeutic agents into cellular compartments. In recent years, a large amount of data on the use of peptides as delivery agents has accumulated. Several groups have published the first positive results using peptides for the delivery of therapeutic agents in relevant animal models. These peptides, called cell-penetrating peptides (CPPs), are short peptides (fewer than 30 residues) with a net positive charge and acting in a receptor- and energy-independent manner. Here, we give an extensive review of peptide-mediated delivery systems and discuss their applications, with particular focus on the mechanisms leading to cellular internalization.Received 14 March 2005; received after revision 25 April 2005; accepted 28 April 2005     

The structure and functions of the presenilins

The presenilins (PSs) were new proteins discovered in 1995 to be involved, among other functions, in the molecular mechanisms leading to Alzheimers disease. These proteins have been the subject of many investigations since then to elucidate their molecular structures and functions. Until now, the conclusions about PS structure have been discordant, but the 8-TM structure has been accepted by the Alzheimers community, with the evidence for the 7-TM structure largely ignored. Here the evidence is reviewed for the 6-TM, 7-TM, 8-TM and other proposed models of PS topography and possibilities offered for the differences in interpretation of the various sets of data. The conclusion is that at this stage, the 7-TM model for cell surface PS is most likely the correct one.Received 22 December 2004; accepted 26 January 2005     

水分胁迫对三种木麻黄小枝活性氧伤害的研究

对三种木麻黄进行水分干旱胁迫处理。结果表明，水分胁迫使木麻黄小枝的相对含水量ＲＷＣ和叶水势ΨＴ下降。木麻黄小枝的Ｏ２＾－产生速率随水分胁迫处理强度加大而增加。ＭＤＡ含量的变化趋势与Ｏ２＾－产生速率的变化趋势相似，ＳＯＤ、ＰＯＤ和ＣＡＴ的活性水平也与Ｏ２＾－的变化相一致，说明木麻黄小枝的水分胁迫损伤，是由Ｏ２＾－引发膜脂过氧化，致使ＭＤＡ含量增加，破坏了细胞膜系统所致，综合结果表明，普通木麻黄具有较