CACHE在磁盘阵列中的应用与实现

本文简要分析了影响CPU和PC性能发挥的若干因素,介绍了减少CPU与内存之间的速度差异的几种办法,指出CACHE法是PC系统不增加大成本的前提下,使其性能提升的一个非常有效的技术。继而详细阐述了CACHE法的设计方法,并结合图解对这种方法的实现进行了介绍。     

μC/OS-Ⅱ在LPC2114上的移植与应用

介绍了当前流行的μC／OS-Ⅱ实时多任务操作系统,分析了ARM嵌入式微处理器LPC2114与移植相关的一些概念,并在此基础上介绍了将μC／OS-Ⅱ移植到LPC2114上的过程以及其应用。     

Co-Mo/γ-Al2O3在合成乙硫醇中的应用

采用等体积浸渍法制备了一系列Co-Mo／γ-Al2O3和K-Co-Mo／γ-Al2O3催化剂,采用XRD技术对催化剂进行了表征,在固定床反应器上评价了催化剂对乙烯和硫化氢合成乙硫醇反应的活性。结果表明,CoO负载量为5wt％、MoO3负载量为10wt％的催化剂活性较好,乙烯的转化率为86,91％,乙硫醇的选择性为68．22％;在Co-Mo／γ-Al2O3催化剂中加入2wt％K2CO3后,乙烯的转化率降低,但乙硫醇的选择性达到了100％。     

直方图均衡化在图像增强中的应用及实现

图像增强是数字图像的预处理,能有效地改善图像的整体或局部特征.直方图均衡化是图像增强领域的一个重要方面.本文研究并探讨了直方图均衡化的基本原理,给出了相关推导公式和算法 并且,以一个灰度图像为例,用Matlab语言工具实现了直方图均衡化增强处理,给出并分析了实验结果.实验结果表明,直方图均衡化能有效地改善图像的对比度并增加像素的动态范围,从而增强了图像.     

Development of antral gastrin-like immunoreactivity and pituitary CCK8/gastrin-like immunoreactivity in rats

Summary Gel filtration of antral extract of adult rats revealed gastrin-17 and gastrin-34. Gel filtration of anterior pituitary extract showed CCK8 and gastrin-17, whereas posterior pituitary extract showed only a CCK8. Antral gastrin-like immunoreactivity (G-LI) increased after milk feeding and especially after weaning was started. Changes in diet may exert a profound influence on the ontogenic development of antral G-LI, but not pituitary CCK8/G-LI.     

Glutathione plays different roles in the induction of the cytotoxic effects of inorganic and organic arsenic compounds in cultured BALB/c 3T3 cells

The cytotoxicity of arsenic compounds towards BALB/c 3T3 cells in culture was investigated, together with the role of glutathione (GSH) in the induction of the cytotoxic effects. The rank order of cytotoxicity was as follows: arsenite (As³⁺)>arsenate (As⁵⁺)>dimethylarsinic acid (DMAA)>methylarsonic acid (MAA)>trimethylarsine oxide (TMAO). Arsenobetaine, arsenocholine and the tetramethylarsonium ion were less toxic. Depletion of GSH enhanced the cytotoxic effects of As³⁺, As⁵⁺, MAA and TMAO, while the cytotoxicity of DMAA was markedly reduced by depletion of GSH. These results suggest that GSH plays a role in protecting the cells against the toxic effects of As³⁺, As⁵⁺, MAA and TMAO while it is involved in the induction of the cytotoxic effects of DMAA.     

APC/C regulation of axonal growth and synaptic functions in postmitotic neurons: the Liprin-{\varvec \alpha} connection

Protein ubiquitination has critical roles in neuronal physiology and defects in protein ubiquitination have been implicated in neurodegenerative pathology. The anaphase-promoting complex/cyclosome (APC/C) is one of two key E3 ubiquitin ligase complexes that functions in regulating cell cycle transitions in proliferating cells by acting on cyclins and components of the mitotic/meiotic apparatus. Documentation of APC/C's action beyond cell division is sparse. In the past year, however, novel and surprising roles for APC/C in postmitotic neurons, particularly in the modulation of axonal growth and synaptic functions, have been revealed. APC/C and its activator Cdh-1 are found in good abundance in neurons, and these seem to function at different cellular locations, modulating apparently diverse processes such as axonal growth and synaptic function. Interestingly, there also appears to be a single link to these apparently divergent actions of APC/C in neurons--the multi-domain, multi-functional scaffolding protein Liprin-alpha which is an APC/C substrate.     

Effects of receptor agonists on polyamine concentrations and spermidine/spermine N1-acetyltransferase activity in rat parotid gland

The polyamine putrescine might be formed via a degradation (catalyzed by spermidine/spermine N¹-acetyltransferase, SSAT) of the higher polyamines spermidine and spermine to putrescine. The involvement of different intracellular signal pathways in the regulation of putrescine formation was studied in explants and in cultured cells of rat parotid glands by using receptor agonists that activate separate second messenger systems, and measuring their effects on the concentrations of putrescine, spermidine and spermine and on the SSAT activity. The -adrenoceptor agonist isoprenaline, which is an activator of cAMP formation, increased the putrescine concentration and stimulated the SSAT activity. Pilocarpine, a drug that activates the muscarinic receptors and thereby enhances the phosphoinositide turnover, had no effect on either the polyamine concentrations or on the SSAT activity. Epidermal growth factor (EGF), which induces activation of a protein tyrosine kinase, had no effect on the polyamine concentrations or on the SSAT activity. The adenylate cyclase activator forskolin increased the glandular levels of putrescine. Taken together, these findings suggest that increases in putrescine concentration in cultured rat parotid gland cells are accompanied by accumulation of cAMP.