微柱高效液相色谱法测定大鼠脑微透析液中 的乙酰胆碱和胆碱

用所建立的微柱高效液相色谱分离、柱后固定化酶反应器酶解、电化学检测器检测的方法, 对用不同浓度异氟醚麻醉前后的大鼠脑微透析液中的乙酰胆碱和胆碱的浓度进行了测定。在 乙酰胆碱和胆碱的浓度为10～ 2 000 nmol/L 时,其浓度分别与各自相应峰高的线性 关系良好,两者的检测限(以信噪比为3计)均可达5 nmol/L 。微透析液中乙酰胆碱和胆碱的含量在大鼠清醒时最高,随着异氟醚吸入浓度的增加,乙酰胆碱和胆碱含量明显降低。在大鼠海马和脑皮层中乙酰胆碱浓度的降低与大鼠吸入异氟醚的浓度相关( P ＜     

黑色素对流感病毒诱导细胞凋亡的抑制效应

用荧光染色技术及流式细胞仪分析方法研究了 Ａ１／京防８６１ 和 Ｂ／沪防９３１ 两株流感病毒感染与细胞凋亡的关系,探讨利用嗜麦芽假单胞菌黑色素抑制流感病毒诱导 Ｍ Ｄ Ｃ Ｋ 细胞凋亡的可能性 结果显示：黑色素在 １００ ｍ ｇ· Ｌ－ １ 浓度范围内,对 Ｍ Ｄ Ｃ Ｋ 细胞无细胞毒性; Ａ１／京防 ８６１ 和 Ｂ／沪防 ９３１ 两株流感病毒均可诱导 Ｍ Ｄ Ｃ Ｋ细胞凋亡,但二者存在毒力差异（ｐ＜ ０．０５）病毒感染１２ ｈ 后,荧光染色可观察到典型的凋亡核形态,流式细胞仪则可检测到病毒诱导 Ｍ Ｄ Ｃ Ｋ 细胞产生的凋亡峰,且细胞凋亡率分别为３７．０２％ 和 ２７２９％ ;２０ ｍ ｇ· Ｌ－ １ 的黑色素可有效抑制两株流感病毒诱导细胞凋亡,使细胞凋亡指数从２５％ ～３５％ 降至３％ 以下 结果表明,黑色素可以抑制 Ａ 和 Ｂ型流感病毒诱导细胞凋亡     

一种蓝色聚合物激光材料

聚合物作为一种有机发光材料,由于在平板显示和光电子器件中的良好应用前景而受到广泛研究［１～２］．近年来,一个重要进展是在聚合物中观测到了受激发射（简称Ｐｏｌｙ－ｍｅｒ激光）现象［３～６］．Ｐｏｌｙｍｅｒ激光最早是在溶液中实现的［３～４］．作为一种新型...     

Pressure effects during pulsed-laser deposition of barium titanate thin films

2 , Ar) in a broad pressure range (10^-7–1 mbar) are correlated to the plasma expansion dynamics. It is found that the deposited films present an excess of Ba in the intermediate pressure range (10^-2<P<10^-1 mbar) and a peaked distribution of Ba to Ti atoms ratio, that is not related to either the substrate temperature or the nature of the gas environment. The results are discussed in terms of the dependence of the plume length (L_P) on the gas pressure and the existence of scattering processes for distances (d) from the target lower than L_P and the diffusion of the ejected species for L_P<d. Received: 7 November 1997/Accepted: 8 November 1997     

Further neo-clerodane diterpenes from Linaria saxatilis (L.) chaz

Ele ven $\text{neo}$-clerodane diterpenoids were isolated from the aerial parts of $\text{Linaria saxatilis}$. Their structures were determined by spectroscopic and chemical methods including the transformation of one of them into the known solidagolactone.     

An EOQ model with backorders and all-units discounts

In this paper we study an inventory model with backorders where the purchase unit price depends on the ordered quantity. This situation appears in practice when a salesperson offers a fixed compensation to a client for not losing the sale and there are quantity discounts. The optimal policy is obtained through a sequential optimization procedure in two stages that relies on a quadratic function (first stage) and on the objective function of the classical EOQ model (second stage). An algorithm is developed for the model and some extensions are commented.     

Ratio limit theorem for parabolic horn-shaped domains

We prove that for horn-shaped domains of parabolic type, the ratio of the heat kernel at different fixed points has a limit when the time tends to infinity. We also give an explicit formula for the limit in terms of the harmonic functions.

     

Level–wise Approximation of a Markov Process Associated to the Boundary of an Infinite Tree

We study an approximation of a Markov process associated to the boundary of an infinite rooted tree. This approximation is constructed by projecting the infinitesimal generator of the original process (defined on the boundary) onto the spaces associated to the filtration spanned by the successive levels of the rooted tree. S. Martínez and J. San Martín acknowledge the support by Nucleus Millenium Information and Randomness P04-069-F. D. Remenik current address: Center for Applied Mathematics, Cornell University, 657 Rhodes Hall, Ithaca, NY 14853. The author acknowledges the partial support by Nucleus Millenium Information and Randomness P01-005 for his work in his undergraduate thesis at Universidad de Chile.     

The relative deformation tensor for small displacements in general relativity

By means of the world-function, an approximate formula for the relative deformation tensor of an elastic continuum in a space-time opf finite curvature is obtained. The coordinate displacements are supposed to be small with respect to the characteristic measure of the geodesic joining an arbitrary point of that continuum and a fixed point of the space-time. The formula contains all the terms up to the third order of approximation with respect to this geodesic measure, which is the basis of the approximation.