Reevaluation of Cl-/HCO3- exchange in cultured bovine corneal endothelial cells

PURPOSE: To determine the apical versus basolateral polarity of the putative anion exchanger in cultured bovine corneal endothelial cells (BCECs) and to examine the influence of Cl--dependent membrane potential (Em) changes on HCO3- transport. METHODS: BCECs grown on permeable supports were used for independent perfusion of apical and basolateral surfaces. Intracellular pH (pHi) was measured using the fluorescent dye BCECF. Relative changes in Em were measured using the fluorescent dye bis-oxonol. Western blot analysis was used to detect immunoreactivity against the anion exchanger (AE1 or AE2). RESULTS: Cl- removal from apical and basolateral surfaces produced cellular alkalinization (apical side, 0.07 pH units; basolateral side, 0.06 pH units; both sides, 0.20 pH units). Application of 100 microM H2-4,4'-diisothiocyanatodihydrostilbene-2,2'-disulfonic acid (DIDS), an anion exchange inhibitor, on the apical side produced an alkalinization (0.02 pH units) followed by acidification (-0.05 pH units), whereas basolateral H2DIDS caused a substantial acidification (-0.16 pH units). In the absence of Na+, Cl- removal from the apical side caused a transient alkalinization (0.03 pH units) followed by a return to baseline; Cl- removal from the basolateral side caused a small (-0.03) acidification. In Na+-free Ringer, apical H2DIDS produced a transient alkalinization (0.02 pH units), whereas basolateral exposure had no effect. 5-Nitro-2-(3-phenylpropylamino)benzoic acid (NPPB), N-phenylanthranilic acid (DPC), and niflumic acid (50-200 microM), known Cl- channel blockers, produced cellular acidification in control Ringer. Niflumic acid hyperpolarized Em and inhibited depolarization after Cl- removal. Western blot analysis failed to detect AE2 expression in cultured BCECs. However, fresh BCECs produced a trace response. CONCLUSIONS: Physiological activity of an apical anion exchanger is weak in cultured BCECs. Cultured BCECs have significant Cl- conductance. Thus, cellular alkalinization after Cl- removal is caused primarily by depolarization of Em, which drives HCO3- influx through the basolateral electrogenic Na+:nHCO3- cotransporter. In contrast with cultured BCECs, AE2 may be present in fresh cells.     

用于计算机教育的Android实验软件(英文)

In this paper,we address the need for better hands-on learning materials in computing education and the need for integrating mobile computing education into computing curricular.We propose an innovative learning approach that uses state-of-the-art mobile computing technologies and devices to design a highly accessible and real-world relevant hands-on labware for computing education.The labware employs a modular design such that the learning materials can both be combined together into a single course of mobile program development and be integrated into the related computing courses as building blocks.The labware will help students understand the concepts,improve their problem solving skills,and prepare them for the mobile computing industrial workforce.The pilot modules of the labware have been presented to undergraduate students and have received positive feedbacks.     

基于MP-BGP扩展的4over6隧道技术的实现

随着IPv4地址资源的日益枯竭,互联网从IPv4向IPv6过渡势在必行。为了进一步推动该校IPv4向IPv6的平稳过渡,文章经过技术论证后,采用MP-BGP扩展的4over6隧道技术,构建了一个IPv4over IPv6实验网络平台,使运行IPv4单协议栈的网络能够跨越IPv6骨干网络实现互联互通。     

谈信息资源管理软件的开发及利用

文章重点阐述了在高职院校信息资源管理艰难的大环境下,我院信息资源管理软件开发使用的环境及过程,重点论述了管理软件的具有的特色及使用过程中遇到的问题。     

采集系统中存储技术的研究

随着光纤技术在嵌入式领域中的应用,通信数据量不断增加,高速采集网络上的数据并正确地存储到磁盘上已成为整个系统的瓶颈。本文从系统基本功能模块出发结合生产者/消费者(Producer-Consumer)模型,对多线程并发、直接读写扇区、异步I/O等技术在系统中的应用进行分析;对系统模型进行抽象,用数学方法对系统进行可行性分析。实验表明,数据采集系统中采用多线程多缓冲的方式在性能上有一定的提高。     

世界杯小组赛出线预测程序

每届足球世界杯都会受到无数人的关注,媒体和个人都很热衷比赛结果的预测。该程序根据世界杯比赛胜负出线规则对比赛结果进行预测。     

水电水利工程压力钢管灌浆孔应力集中敏感性因素研究

水电水利工程压力钢管开孔灌浆后,需对灌浆孔严密封堵,处理不好会对工程安全运行留下隐患。在总结国内外灌浆孔常用封堵方案基础上,以某水电站地下埋管为例,建立平面有限元模型,分析其灌浆开孔后管壁应力集中现象,研究了补强板厚度及堵头坡口深度对压力钢管灌浆孔应力集中的敏感性。结果表明,应力集中程度随补强板厚度及堵头坡口深度增加递减,堵头坡口深度对其影响更加敏感。对于地下埋管管壁上开灌浆孔的非高强钢,建议灌浆后孔口进行封堵,补强板厚度宜与钢管壁厚相同,并适当增加坡口深度。当钢管壁厚较大时,堵头坡口深度宜不小于钢管壁厚的1/4~1/3。     

有机磷灭蚊剂投放浓度和时间对水体总磷的影响

为分析新型低毒有机磷杀虫剂“1%双硫磷颗粒”投放对河道水质的影响,设置不同药剂投放浓度和不同反应时间的室内试验,以TP、NH₃-N及S^2-为目标因子,分析该药剂投放后水体污染物浓度。结果表明:不同试验组水样中S^2-质量浓度均小于0.02 mg/L,NH₃-N质量浓度处于0.029~0.036 mg/L之间,均达到地表水Ⅰ类标准;不同浓度药剂投放1 h后,水体TP质量浓度已达到稳定状态,且在60 h内均保持稳定,药剂投加量与水体TP质量浓度呈显著正相关(R²=0.85);不同处理组的药剂在水体中的TP释放量无明显差异,均在1.06~1.30 mg/g之间。“1%双硫磷颗粒”推荐适宜投放量不会使河道水质恶化到劣Ⅴ类,但增加药剂投放量会增加水体TP污染及富营养化风险。