pH Dependence of Chlorophyll States, Protein Structures and Function of the PSII Membranes

IntroductionPhotosystem II ( PSII) is a pigment- proteincomplex in the thylakoid membrane. Its reactioncenter( PSII- RC) ,which is composed of D1 andD2 proteins,generates the highly positive oxidantrequired for the oxidation of water by light- drivencharge separation. Water oxidation occurs at theMn4cluster positioned atthe center of the oxygen-evolving complex on the lumenal surface of PSII.In green plants,the highly reactive Mn4cluster isshielded by a number of extrinsic proteins( 33…     

机关事业单位养老保险改革应当兼顾公平与利益

推进机关事业单位养老保险改革是我们社会保障制度改革的重要内容。机关事业单位传统的退休养老制度与企业职工基本养老保险已出现明显的鸿沟,不利于机构改革深化和人力资源正常流动。本文认为改革的难度在于既要增进不同职业身份人员参保的公平性,又要考虑改革对既得利益群体的冲击大小,才能保证改革的顺利推进。并在此基础上提出了对我国机关事业单位养老保险改革的短期、中期和长期设想。     

Heat Denaturation of Protein Structures and Chlorophyll States in PSII Membranes

IntroductionPhotosystem II (PSII) is a large supramolecularpigment-protein complex found in the thylakoidmembranes of green plants,algae andcyanobacteria.Its main role is to drive light-induced electron transfer from water toplastoquinone with a concomitant production ofmolecular oxygen.PSII membranes consist of anouter antenna portion of light-harvestingchlorophyll (Chl) a/b binding complexes (LHCII)and a core fraction.The core fraction is composedof an inner antenna of membrane-bound …     

抗紫杉醇抗体的制备方法

用化学方法将紫杉醇（Ｔａｘｏｌ）与牛血清白蛋白（ＢＳＡ）偶联制成全抗原Ｔａｘｏｌ－ＢＳＡ．以Ｔａｘｏｌ－ＢＳＡ免疫家兔后收集抗血清，分离纯化抗体，经酶联免疫吸附法测定证实抗血清中有特异性抗紫杉醇抗体，将纯化的抗体进行免疫双扩散鉴定，结果表明其有较高滴度（３．２×１０２）．     

扩底桩及浅基础的界定与计算分析

为了解决扩底桩深基础与普通桩基及浅基础的区分及设计计算,根据均布荷载下的Boussinesq与Mindlin解,结合现有文献对"扩底桩"或"扩底墩"等扩底深基础进行界定,对其承载能力特性进行计算分析.结果表明:扩底深基础与普通桩基的区别是扩大头因素的存在.通过对不同形式基础底部附加应力的计算可知,若以两者差异δ=0.2为基准对扩底基础的深浅进行界定,则埋深与扩底直径之比宜取0.62,并将其作为深浅基础的划分界限,而且实际工程亦验证了此界限的可靠性.     

大直径扩底桩竖向端承力解析解与试验分析

为了解决目前大直径扩底桩竖向端承力计算方法所存在的不足,将球孔扩张理论应用于扩底桩端承力的计算,建立了扩底桩的球孔扩张理论计算模型.考虑扩底桩桩端外边缘处力矩平衡以及几何对称性,建立极限球孔扩张压力、桩端中心以下主动土压力及扩底桩端承力之间的联系,推导出大直径扩底桩端承力的解析解,求得黏性土和无黏性土中扩底桩端承力的表达式.利用原型扩底桩试验对该公式进行验证,分析得出影响扩底桩端承力的主要因素包括土的粘聚力、内摩擦角、杨氏模量、泊松比、扩底桩的扩底半径和入土深度.试验结果表明:该解答精度满足工程要求;经验方法对扩底桩端承力进行折减只是经验的总结,物理意义不明确.     

Transient Effects of Salt Shock on the Photosynthetic Machinery in Synechocystis sp. PCC 6803

IntroductionSalt stress is one of the main detrimental factors inthe environment that limit the growth andproductivity of plants.Salt stress causessignificant decreases in photosynthetic activity,such as the electron transport[1,2 ] ,but themechanisms by which salt stress inhibitsphotosynthesis remain poorly understood[3] .　Cyanobacteria are prokaryotes that performoxygenic photosynthesis using a photosyntheticapparatus similar to that in the chloroplasts ofgreen algae and higher plants[4 ] .…