Interaction of catechins with aluminum in vitro

Tea is one of the most popular beverages, consumed by over two thirds of the world's population; but the aluminum accumulation property of tea plant is becoming the focus of many researches because of aluminum's known adverse effect on human health. Investigation of the interactions of catechins with Al(3+) showed that during the interaction of catechins with Al(3+), the UV-vis spectrum of catechins was changed. Absorption of EGCG at 274 nm decreased and increased at 322 nm; EC and C's at 278 nm changed little. The ratio of Al(3+) to EGCG was 1:1 in pH 5.0 buffer solution; in pH 6.2 buffer solution, the ratio in the Al-EGCG complex was 1:1. Interestingly, while the ratio reached to over 2, after the complex of Al-EGCG started polymerization, the ratio in the polymer was 2:1. In pH 6.2 buffer solution, the complex behavior of C with Al(3+) was the same as that of EGCG, with a little difference for EC. When the ratio of Al(3+) to EC was <1, the complex in ratio was 1:2, but, the complex polymerized when the ratio of Al(3+) to EC was >1. It was found that the ratio of Al(3+) to EC in the polymer was 1:1. Polymerization of Al-catechin complexes might reduce aluminum absorption in the intestine. Kow value was also employed to study the properties of aluminum species in tea infusion (at gastric and intestine pH condition) and the effect of catechins and tea polyphenols on Kow in buffer solution. Results showed that Kow value rose much higher at the intestine pH than at the gastric pH. Tea polyphenols and catechins could greatly reduce aluminum Kow value in acetic buffer, indicating that these compounds may reduce aluminum absorption during tea intake.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower ()rdovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as “oil families“, although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any “oil family“. Despite their close stratigraphic proximity, it is evident that the oils of the/rower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new “oil family“ within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

THE TCF BLEACHING OF NS-AQ ASPEN HIGH YIELD CHEMICAL PULP

INTRODUCTIONNowadays, under the pressure of energy crisis, Methods押The pulp was put in the high-density polyethylene plastic bag in the of thermostatic water bath where the pulp was treated with chelated environment pollution and market competition, the pulp industry has being developed in the direction of "Three Highness" and " Three Lowness". "Three Highness" means high yield, high strength and high brightness; on the other hand, " Three Lowness" means low energy consumption, low wa…     

双曲旋轉与狹义相对論中某些反常現象的几何解释

本文是写给中学数学教师的,但是也可以在中学教学和物理小组中采用。本文主要是利用数学分析方法讲述高速力学中一系列的反常规律。这些材料可以使学生更深刻地了解数学方法在深入研究客观世界规律中的意义。 1.普通旋轉与双曲旋轉 考虑中心在坐标原点的单位圆。这个圓的方程为 x~2+y~2=1,(1)或用参数表示为由此看出,用弧度表示的圆心角(φ)与对应的扇形面积(α)有下面的关系:     

紧致性在分析中的作用

引言.分析是数学中一个广阔的领域,紧致性概念与论証已深入到分析的許多不同分支中。要对紧致性在分析中的作用给出一个恰如其分的描述,实际上就要求多方面研究数学分析。显然,一篇短文是不可能完成这一任务的,更不用说作者本人知识的局限性了。因此,我们打算这样叙述。引入紧致性这一概念后,从分析的各个不同部门中举出一些必须假设紧致性的例子。这些例子包括从极其初等到相当复杂的各种情形,其中一部分是阐述这一概念的,另一部分则是分析中的一些重要定理。我们不打算做到详尽无遗。紧致性在許多存在定理中作为一种証明的工具。由于篇幅的限制,我们将只简单地描述如下。数轴上的紧致子集.人们早就理解了数轴R上子集的紧致性,并加以研究和运用。设A是数轴上的一个子集,我们来考虑下列三种性质(暂且不管A是否具有这些性质):     

某些物理量的相互关系

本文以比較簡单的物理概念,导出了銅和鉛的楊氏模量、熔点、膨胀系数、潛热和表面张力。目的在于为上述这些物理量間相互关系提供一簡易証明。固体中的銅原子在偏离平衡位置时要引起恢复力的产生,对于很小的位移,可以认为恢复     

程序設計

最近十年来,在計算技術方面起了很大的变革,这就是数字电子計算机的出現,它工作的速度快到我們不可能用手來操縱它,而要由机器本身進行自动的操縱。数字电子計算机的重要組成部分是輸入、存儲、运算、控制、输出(图1)。     

中学一般技術小組

在对学生進行綜合技術教育和培养他們將來从事实际工作的事業里,很好地組織課外的活动有着重大意义。在課外活动里,学生可以擴大和加深自己的知識,獲得实际的技能和技巧。     

铝热法的反应

以铝(铝热法)来还原金属氧化物的反应,有着很重大的实用意义。利用铝热法可以获得一系列的金属(如Cr,Mn,V等等)。在中等学校里,铝热法反应的实验通常是按照维尔贺夫斯基教授所写的以“学校化学实验法和技术”为主的材料进行的。进行这种实验,除加热剂外,平常是应用特种可燃的混合物;这种混合物是由铝粉和过氧化钡以及一小条的镁条组成的。如果     

有关大型汽输发电机设计的一些问题

大型二极发电机的转子是在接近或高于其转轴的第二临界转速下运行的。临界转速受轴承支承的刚度、转子各部件的施工设计以及与汽机主轴联接方式的影响。本文对这些影响做了说明。转子平衡对发电机的平稳运转是很重要的,作者认为平衡问题无论在设计和制造阶段,还是在平衡坑内校平衡时,都必须十分注意。对大型发电机的轴承提出相互矛盾的要求,既要求它的轴颈传递很大的突然短路转矩,又要求轴承损耗最小。本文提出轴承尺寸与发电机功率的关系,并讨论了如何设计轴系以减小经由轴颈所传递的短路转矩。随着发电机功率和转子柔度的增加,本文所述问题显得日益重要。