Harmonic Functions on Homogeneous Spaces

 Given a locally compact group G acting on a locally compact space X and a probability measure σ on G, a real Borel function f on X is called σ-harmonic if it satisfies the convolution equation . We give conditions for the absence of nonconstant bounded harmonic functions. We show that, if G is a union of σ-admissible neighbourhoods of the identity, relative to X, then every bounded σ-harmonic function on X is constant. Consequently, for spread out σ, the bounded σ-harmonic functions are constant on each connected component of a [SIN]-group and, if G acts strictly transitively on a splittable metric space X, then the bounded σ-harmonic functions on X are constant which extends Furstenberg’s result for connected semisimple Lie groups.     

Separation of double-stranded DNA fragments in plastic capillary electrophoresis chips by using E99P69E99 as separation medium.

The separation of double-stranded DNA (dsDNA) fragments in polymethylmethacrylate (PMMA) capillary electrophoresis (CE) chips by using E99P69E99 as a separation medium has been demonstrated. The PMMA CE chips were simply manufactured by micromachining and adhesive tape sealing. To make the separation channel compatible with the separation medium, a dynamic nonionic surfactant coating procedure was developed, which made the plastic separation channel sufficiently hydrophilic to allow the separation medium to fill the channel by capillary action. Subsequent separation of DNA fragments was successful with a separation efficiency of the order of 10(4) theoretical plates over an effective separation distance of 1.5 cm. By using an applied electric field strength of 200 V/cm, the separation of low DNA mass ladder was completed within 5 min. The simple coating procedure, together with the self-assembled viscosity-adjustable separation medium, should be useful to meet some of the essential requirements for developing single-use disposable CE chips. Coating the channels with polymer blends of PMMA and the separation medium also showed promise.     

Poly(N-isopropylacrylamide)-g-poly(ethyleneoxide) for high resolution and high speed separation of DNA by capillary electrophoresis.

A new separation medium, poly(N-isopropylacrylamide)-g-poly(ethyleneoxide) (PNI-PAM-g-PEO) solution, used for double-stranded (ds) DNA separation by capillary electrophoresis (CE) is presented. This type of grafted copolymer has a good self-coating ability for quartz capillary tubing and a slightly temperature-dependent viscosity-adjustable property, making it easier to use. One bp resolution was achieved within 12.5 min by using 8% w/v PNIPAM-gPEO in 1 x TBE (Tris-borate-ethylenediaminetetraaceticacid) buffer with an effective column length of 10 cm and an applied electric field strength of 200 V/cm. The PNIPAM-g-PEO solutions had a high sieving ability for relatively small sized DNAs with the relative standard derivation for the first 10 runs being less than 0.9% by using the same polymer solution. With 8% w/v PNIPAM-g-PEO solution in a 1.5 cm column and 2400 V as the running voltage, phiX174/HaeIII digest could be clearly separated within 24 s.     

Vitamin K1在水-有机溶剂中单电子还原电位的测定

Vitamin K1(VK1)是一种非常重要的脂溶性维生素,其止血功能已为人们所熟悉.下图显示在生物体内VK参与的止血过程,在这个氧化还原循环过程中,VKH2环氧化变成VKO与－Glu－(谷氨酸蛋白)羧化而转变成－Gla－(γ－羧基谷氨酸蛋白)是同时发生的,但前一过程对后一过程有什么贡献至今还不清楚.     

苯并呋喃并香豆素的合成及其钙拮抗活性初步研究

１引言香豆素是一类具有重要生理活性的天然产物,具抗凝血、抗肿瘤、抗病毒等多种活性,最近又发现某些香豆素化合物具有钙桔抗活性［‘,’］。目前对此类物质钙站抗活性的研究国内外还开展较少。我们设计合成了一系列苯并吠哺并香豆素化合物,选取其中三个（;、Ｄ。、Ｄ３）＄０一个简单二羟基香豆素（Ｃ。）经放射性‘’Ｃａ跨膜流动技术测定,表明其对电压依赖性钙离于通道（ＰＤＣ）均有较显著阻滞作用（见表１）。其中Ｄ。未见文献报道,其结构经ＮＭＲ、ＩＲ、ＭＳ确证。已知物Ｄ;、Ｄ。和Ｃ。的钙通道阻滞活性尚未见其它文献报道…     

锂离子电池锂锰氧化物高压嵌锂材料的结构和电化学性能研究

利 用 Ｘ Ｒ Ｄ、 Ｉ Ｃ Ｐ、 Ｔ Ｇ Ａ 、 Ｄ Ｔ Ａ 及 恒 流 充 放 电 等 方 法 研 究 分 析 了 一 种 特 殊 天 然 结 构 Ｍｎ Ｏ２（ Ｎ Ｍ Ｄ） 材料的结 构、组成 以及电 化学嵌锂 特性． Ｘ Ｒ Ｄ 分析 表明,该样 品材料 是由钠水 锰矿以及水羟 锰矿复 合结构组 成的 Ｍｎ Ｏ２ 纳米 纤 维． 充放 电 循环 结果 显 示,其 前 期循 环容 量 可高 达 １５０ｍ Ａｈ／ ｇ 左 右,但性 能尚不够 稳定． 本文采 用一种 水热法高 压嵌锂处 理,可将 Ｎ Ｍ Ｄ 样品 转变为 具有３ ×３ 大隧道结 构的钡 镁锰矿（ Ｔｏｄｏｒｏｋｉｔｅ） 型锂 锰氧 化 物,既 增 强了 Ｌｉ ＋ 嵌 入 隧道 或 层间 结 构 的循环稳定 性． 并 显著提 高锂锰氧 化物电 极材料性 能的 稳定 性,以 充放 电电 流密 度 为０ ．８ ｍ Ａ／ｃ ｍ ２ ,经过１８０ 次 循环后 其比容量 仍具有 １１０ ｍ Ａｈ／ ｇ ． 该类 大隧道结 构锂锰 氧化物可 作为一 种３ Ｖ 的锂离子电极 材料．     

p53 induction in normal human skin in vitro following exposure to solar simulated UV and UV-B irradiation.

Exposure of normal human breast skin ex vivo to physiological levels of UV-B and solar simulated UV results in a UV dose- and time-dependent increase in epidermal p53, as determined by PAGE analysis. Peak p53 levels are detected 12 to 24 h post irradiation with UV-B (470-1410 mJ cm-2) and solar simulated UV (5-12 minimal erythema dose (MED) equivalents). Irradiation with an FS20 UV-B lamp, contaminated with UV-A and UV-C (74-1111 mJ cm-2), also induces peak levels after 12 h incubation at 37 degrees C but these levels persist to 36 h post UV irradiation. In all cases p53 levels start to return to normal by 48 h culture. A significant positive correlation is demonstrated between UV-B dose (47-1645 mJ cm-2) and p53 level (p < 0.01, R > 0.977) in explants cultured for 24 h at 37 degrees C post irradiation. The FS20 induces a 'UV-B' dose-dependent increase in p53 to a maximum from 370 to 1111 mJ cm-2. Similarly, solar simulated UV induces a plateau of peak p53 induction between 5 and 15 MED equivalents. Immunohistochemical analysis using microwave retrieval on 5 microns sections shows the same pattern of p53 staining with UV-B and solar UV insult, but proves unreliable as a method of quantification. These results suggest that the skin explant model may be a useful tool in the evaluation of UV-induced epidermal cell damage, providing a valuable alternative to in vivo studies.     

漆树漆酶的催化氧化作用 (ⅹⅢ)──Fe~(2+)离子对漆酶催化氧化反应的影响()

以５,６－二溴－２,３－二氰基氢醌为底物,在ｐＨ４．５０条件下,用分光光度法考察了ＦｅＳＯ４对漆树漆酶催化氧化反应的影响．结果表明,在本文实验条件下ＳＯ２－４离子对酶促反应的影响基本可以忽略,而Ｆｅ２＋离子对漆酶的催化氧化反应则有明显的竞争性抑制作用．研究证实,Ｆｅ２＋离子的抑制作用是通过它还原酶促反应的产物半醌自由基阴离子来实现的     

LOAD CAPACITY OF OILFILM——LUBRICATED BALL-BEARING WITH SPIRAL GROOVES

In order to improve load capacity and stability of a fluid moving-pressure bearing, at present, measure of cutting grooves on a turning-shaft is generally adopted.The performances of spiral grooves are better in various groovetypes. Therefore, a theoretical analysis and an experimental investigation of the bearing with spiral grooves attract general attention. But the results of most articles published in china are numerical solutions of the computer. Using the methods of parameter perturbation in the paper, an approaching analytical solution of Reynolds equation of the moving-pressure oilfilm-lubricated ball-bearing with spiral grooves has been obtained. We have combined the numerical solutions of the computer, and the influence of the bearing parameters upon the load capacity is discussed; the optimum values of the groove parameter are obtained. The theoretical conclusion of this paper is in good agreement with the experimental data obtained by 651 Institute.