The annexins: spatial and temporal coordination of signaling events during cellular stress

Annexins are a family of structurally related, Ca²⁺-sensitive proteins that bind to negatively charged phospholipids and establish specific interactions with other lipids and lipid microdomains. They are present in all eukaryotic cells and share a common folding motif, the “annexin core”, which incorporates Ca²⁺- and membrane-binding sites. Annexins participate in a variety of intracellular processes, ranging from the regulation of membrane dynamics to cell migration, proliferation, and apoptosis. Here we focus on the role of annexins in cellular signaling during stress. A chronic stress response triggers the activation of different intracellular pathways, resulting in profound changes in Ca²⁺ and pH homeostasis and the production of lipid second messengers. We review the latest data on how these changes are sensed by the annexins, which have the ability to simultaneously interact with specific lipid and protein moieties at the plasma membrane, contributing to stress adaptation via regulation of various signaling pathways.     

Calcium accelerates cholesterol phase transitions in analog bile

Summary Analog bile supersaturated with cholesterol was constituted, filtered and divided into equal portions containing no calcium or calcium, 2.5–15 mM. Aliquots were removed over the next 48 h and filtrates analyzed for cholesterol, bile acid and lecithin. Calcium accelerated cholesterol loss from solution in a dose-related fashion.     

用离子选择性电极法测定大米中的鈣

应用离子选择性电极法测定大米及强化大米中的钙,研究了酸度、离子强度对测定溶液中钙的影响,在最佳条件(pH7.0～10.5,0.20mol/L KNO_3)下,灵敏度可达1.15×10~(-5)mol/LCa~(2+)。在马福炉中对样品进行灰化处理,并进行回收实验,回收率良好。本法测定结果与原子吸收法的测定结果相对照,基本一致。     

青海农区钙层土氮矿化势和供氮速率常数估测

利用一级动力学方程对青海农区栗钙土、灰钙土的氮矿化势和矿化速率常数进行测定，结果表明栗钙土比灰钙土有更高的供氮容量，而供氮强度与环境水分条件有较明确的关系。     

氯化钙型锌锰干电池的研制

研制了一种新型电解液，其成分以氯化钙为主，制成的成品电池放电性能优良，具有耐低温，防温液，贮存期长等优点。     

中国西南部第四纪碳酸钙年代与古环境的地球化学特征

喀斯特地区的泉水和溪流水中沉淀下来的一种次生沉积物，是由碳酸钙过饱和沉淀产生的．碳酸钙沉积或沉积多寡受到多种因素的控制和影响，其中古环境，特别是古气候，影响尤甚．我们通过同位素测年工作，探讨了云贵高原第四纪以来的古环境的演递及其发育历史．     

PS4.0微机极谱法测定食品中微量钙

采用PS4.0微机极谱仪标准加入法测定了食品中的微量钙 ,采用DTD -40型恒温消解仪消化食品 ,检测下限 1 0 0 μg/L ,线性范围 0 .1 0～ 4.0 0mg/L ,相对标准偏差为 6.62 % ,回收率为97 2 % .锌、锰、铅、铜、镉不干扰测量 .分析结果令人满意     

油田水CaCO_3结垢反应的计算与应用

以热力学计算为基础，广泛采用油田水的数据．计算了ＣａＣＯ３的预测条件，并根据油田生产实际，建立了使用防垢剂时的预测模型．根据理论模型编制成计算机程序，并与文献结果和油田观测结果进行了对比，提出了临界浓度和临界稳定常数的计算和应用方法．为防垢剂的选择提供了理论依据，大量计算表明，预测结果与文献和现场观测结果相符．     

多波长数据线性回归光度法同时测定钙和镁

本文研究了酸性铬蓝K体系用于同时测定钙和慎的显色条件，借助多波长线性回归法处理数据，提出光度测定钙和镁的简便方法，免去了分离手续。应用于三个水样中钙、镁含量的测定，结果满意。