On the mechanism of inhibition of p27 degradation by 15-deoxy-Δ12,14-prostaglandin J 2 in lymphoblasts of Alzheimer’s disease patients

It has been proposed that neuroinflammation, among other factors, may trigger an aberrant neuronal cell cycle re-entry leading to neuronal death. Cell cycle disturbances are also detectable in peripheral cells from Alzheimer’s disease (AD) patients. We previously reported that the anti-inflammatory 15- deoxy-Δ^12,14-prostaglandin J ₂ (15d-PGJ ₂) increased the cellular content of the cyclin-dependent kinase inhibitor p27, in lymphoblasts from AD patients. This work aimed at elucidating the mechanisms of 15d-PGJ ₂-induced p27 accumulation. Phosphorylation, half-life, and the nucleo-cytoplasmic traffic of p27 protein were altered by 15d-PGJ2 by mechanisms dependent on PI3K/Akt activity. 15d-PGJ ₂ prevents the calmodulin-dependent Akt overactivation in AD lymphoblasts by blocking its binding to the 85-kDa regulatory subunit of PI3K. These effects of 15d-PGJ ₂ were not mimicked by 9,10-dihydro-15-deoxy-Δ^12,14- prostaglandin J ₂, suggesting that 15d-PGJ ₂ acts independently of peroxisome proliferator-activated receptor γ activation and that the α,β-unsaturated carbonyl group in the cyclopentenone ring of 15d-PGJ ₂ is a requisite for the observed effects. Received 14 July 2008; received after revision 2 September 2008; accepted 12 September 2008     

Parasite fauna of the grey mullet Mugil cephalus L. 1758, and its relationship with some ecological factors in Lower Kızılırmak Delta located by the Black Sea,Turkey

Parasites of the grey mullet Mugil cephalus collected from Lower K?z?l?rmak Delta in Turkey were investigated. Trichodina puytoraci, Trichodina lepsii, Ligophorus mediterraneus, Ligophorus cephali, Gyrodactylus sp., Microcotyle mugilis, Ascocotyle (Phagicola) longa, Haplosplanchnus pachysomus, Diplostomum spathaceum, Tylodelphys clavata, Posthodiplostomum sp., Neoechinorhyncus agilis and Ergasilus lizae were identified. Overall infection prevalence (%), mean intensity and mean abundance values were 99.61%, 458.10 ± 75.72 and 456.30 ± 75.44, respectively. Infection indices of parasite species in relation to season, lakes/lagoons and some physicochemical parameters of water such as temperature, salinity, dissolved oxygen and nitrate are determined and discussed. Posthodiplostomum sp. is a new parasite record for mugilids and Diplostomum spathaceum is the first record in M. cephalus, in the present study. Moreover, Ligophorus mediterraneus, Ligophorus cephali and Ergasilus lizae are new records for Turkish parasite fauna of fish and Mugil cephalus is a new host record for Neoechinorhyncus agilis in Turkey.     

2．725K的宇宙空间背景辐射成为空间物质构成电子的证据^[1]

本文科学地将发现宇宙空间2．725K温度的背景辐射同经典物理学有机的衔接起来，并依此推导出电子的质量，由此证明电子是由宇宙空间产生的并同宇宙空间具有相同的组成成分-空间基本单元．同时根据电子经典半径R0、电子康普顿波长五，及电子质量反演出宇宙空间背景辐射温度为2．72147K．     

关于Zeta函数值的一个注记

关于Zeta函数的特殊值，Browkin曾猜测有等式｜ζ（-1）｜=R2k2/ω2，然而，在F是有复素位的数域情形下，可判定此等式不成立。主要的方法是利用有关Bloch群的一个定理及zeta函数方程作一些计算，然后和猜测的等式进行比较，导出矛盾。     

PP333对水稻幼苗几种大量元素吸收及其外流的示踪研究

水培“特青”水稻幼苗经0.2及0.4ppm PP333处理5天,植株生长没发生明显变化,但植株矿质元素含量及根系离子外流都发生变化.在根系,~(32)P及~(36)Rb(K)含量显著增多,~(45)Ca含量减少;在地上部,~(32)P及~(45)Ca含量增多,~(36)Rb(K)含量无明显变化.根系~(36)Rb(K)及~(45)Ca的外流显著地受到PP333的抑制.结果表明,PP333主要是提高了水稻幼苗各部位矿质元素含量,并抑制根系离子的外流.     

热等静压处理对K17合金元素偏析的影响

本文研究了热等静压(HIP)处理对K17合金主要含金元素偏析的影响.实验结果表明,热等静压处理可以显著减轻K_(17)合金主要合金元素的树枝状偏析和共晶反应偏析,使合金成分趋于均匀,从而抑制了σ相的析出.     

以K[Al（OH）4]铝化硅胶的研究

以Ｋ〔Ａｌ（ＯＨ）４〕对硅胶进行铝化。用ＸＰＳ（光电子能谱）、ＩＲ（红外）、ＭＡＳＮＭＲ（魔角核磁共振）以及异戊醇脱水反应表征了铝化胶样品。结果表明，硅胶经后可以产生Ｂｒｏｎｓｔｅｄ和Ｌｅｗｉｓ酸性。Ｂｒｏｎｓｔｅｄ酸性的产生不排除Ｋ〔Ａｌ（ＯＨ）４）〕与硅胶表面羟基综合并在以后的热处理中转化为六配位的铝氧化物，从而显示ｌｅｗｉｓ酸性。铝化硅胶由于具备了酸性，产生了醇脱水的催化活性。     

高温对人红细胞的影响

高温用于恶性肿瘤的治疗是近年来颇受重视的工作,但高温处理不可避免地对肿瘤组织周围正常细胞也将产生影响。为了研究高温对正常细胞的影响,本文以人红细胞为实验模型,研究其细胞热损伤的机制。红细胞经不同温度处理二十分钟后,通过扫描电镜和生化分析方法探讨红细胞的形态变化,溶血作用和膜结合酶-乙酰胆碱酯酶、Na·K·Mg-ATP酶活性的变化。结果表明,在本实验条件下细胞形态的改变对高温最敏感:48℃高温处理后,绝大部分细胞变形,50℃保温使溶血显著增加,膜结合酶热变性温度则超过54℃。     

天女木兰研究现状及保育对策

概述了天女木兰的地理分布、生物学和生态学特性、繁殖技术、经济价值及开发利用等方面的研究现状,指出了天女木兰应用和研究中存在的问题,提出了对天女木兰保育和开发利用的策略.     

空间聚类算法中的K值优化问题研究

在典型的空间聚类算法K-平均法和K-中心法中,K一般为用户事先确定的值,然而,实际中K值很难被精确地确定,往往表现为一个模糊的取值区间。在此提出距离代价函数的概念,建立了相应的数学模型并设计了一个新的K值优化算法,对空间聚类K值优化问题进行了初步的研究。