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991.
992.
A growing body of research suggests that inflammatory insult contributes to the etiology of central nervous system diseases, such as depression, Alzheimer’s disease, and so forth. However, the effect of prenatal systemic inflammation exposure on offspring brain development and cerebral susceptibility to inflammatory insult remains unknown. In this study, we utilized the prenatal inflammatory insult model in vivo and the neuronal damage model in vitro. The results obtained show that prenatal maternal inflammation exacerbates LPS-induced memory impairment, neuronal necrosis, brain inflammatory response, and significantly increases protein expressions of COX-2, DP2, APP, and Aβ, while obviously decreasing that of DP1 and the exploratory behaviors of offspring rats. Meloxicam significantly inhibited memory impairment, neuronal necrosis, oxidative stress, and inflammatory response, and down-regulated the expressions of APP, Aβ, COX-2, and DP2, whereas significantly increased exploring behaviors and the expression of DP1 in vivo. Collectively, these findings suggested that maternal inflammation could cause offspring suffering from inflammatory and behavioral disorders and increase the susceptibility of offspring to cerebral pathological factors, accompanied by COX-2/PGD-2/DPs pathway activation, which could be ameliorated significantly by COX-2 inhibitor meloxicam treatment.  相似文献   
993.
低轨(LEO)卫星跳波束技术可以灵活分配系统资源,适用于业务分布不均匀的场景。时分双工(TDD)方式可以减少星载和地面终端设备的天线数量,有效降低其复杂度,并有利于开展上下行非对称业务。本文提出一种基于TDD的LEO卫星跳波束资源分配算法,在满足业务需求的基础上,以最小化时域资源消耗为目标,建立支持跳波束和多频时分多址接入(MF-TDMA)机制的LEO卫星反向链路资源分配模型;综合考虑星地动态时延补偿,采取一种多层次的跳波束时隙架构设计,以最大化可用时隙为目标,建立上下行时隙切换模型,并提出一种基于TDD的跳波束时隙排布优化方法。仿真结果表明,对比于传统的MF-TDMA资源分配方法或固定多波束均分算法,本文提出的算法能有效提高系统的时隙利用率和吞吐量。  相似文献   
994.
A series of experiments were performed on three types of closed loop pulsating heat pipes(PHPs),intending toinvestigate various kinds of flow patterns,and to develop some improved configurations for the PHPs.Opticalvisualization results indicated that there might exist three flow patterns,i.e.bubble-liquid slug flow,semi-annularflow and annular flow,corresponding to different working conditions.For a given geometry and an adequate fillratio,the PHPs had the self-adjusting characteristic for the flow patterns(from slug flow to semi-annular and thento annular flow)to meet the demands of the increasing heat input.Two special configurations,one with alter-nately varying channel diameter,the other equipped with one section of thicker tube,were found to be advanta-geous in establishing and maintaining reliable circulation of the working fluid.The thermal performance of thePHPs was examined over a range of working conditions.Comparing with the normal PHP with uniform diameter,either of the improved PHPs exhibited higher thermal performance.  相似文献   
995.
摩擦改进剂对改善燃油经济性的影响研究   总被引:2,自引:0,他引:2  
李桂云  刘岚  陈刚  金理力  蔡继元 《润滑与密封》2007,32(4):140-141,144
采用四球机试验,考察了钼胺化合物、二烷基二硫代氨基甲酸钼、无灰型摩擦改进剂与摩擦因数的关系以及它们之间的复配作用。结果表明:摩擦改进剂(FM)降低摩擦因数的效果与其化学结构有关;加入量提高,摩擦因数的改善效果明显;不同化学结构的摩擦改进剂复配使用,可以减低整个温度区的摩擦因数。  相似文献   
996.
陈冀渝 《石材》2007,(7):12-13
当今,石材薄板的加工与应用已成为发展的方向。因为这对节省资源和能源,提高资源利用率,减轻建筑物负重,降低运输和施工费用起着十分重要的作用。因此,十分有必要突破石材“瘦身”的技术瓶颈问题。笔者编译了国外文献中有关石材块料薄切工艺的文章,推荐给读者,以供借鉴。  相似文献   
997.
运用X射线荧光光谱法对石榴石分类鉴定   总被引:2,自引:0,他引:2  
本文介绍了运用X射线荧光光谱法对石榴石的化学组成元素进行剖析(定性及半定量分析),通过化学组分的不同来对石榴石进行分类、鉴定。  相似文献   
998.
Temperature-sensitive genic male sterile (TGMS) line Beijing Sterility 366 (BS366) has been utilized in hybrid breeding for a long time, but the molecular mechanism underlying male sterility remains unclear. Expression arrays, small RNA, and degradome sequencing were used in this study to explore the potential role of miRNA in the cold-induced male sterility of BS366. Microspore observation showed defective cell plates in dyads and tetrads and shrunken microspores at the vacuolated stage. Differential regulation of Golgi vesicle transport, phragmoplast formation, sporopollenin biosynthesis, pollen exine formation, and lipid metabolism were observed between cold and control conditions. Pollen development was significantly represented in the 352 antagonistic miRNA-target pairs in the integrated analysis of miRNA and mRNA profiles. The specific cleavage of ARF17 and TIR1 by miR160 and miR393 were found in the cold-treated BS366 degradome, respectively. Thus, the cold-mediated miRNAs impaired cell plate formation through repression of Golgi vesicle transport and phragmoplast formation. The repressed expression of ARF17 and TIR1 impaired pollen exine formation. The results of this study will contribute to our understanding of the roles of miRNAs in male sterility in wheat.  相似文献   
999.
Mammalian adipose tissue can be divided into white and brown adipose tissue based on its colour, location, and cellular structure. Certain conditions, such as sympathetic nerve excitement, can induce the white adipose adipocytes into a new type of adipocytes, known as beige adipocytes. The process, leading to the conversion of white adipocytes into beige adipocytes, is called white fat browning. The dynamic balance between white and beige adipocytes is closely related to the body’s metabolic homeostasis. Studying the signal transduction pathways of the white fat browning might provide novel ideas for the treatment of obesity and alleviation of obesity-related glucose and lipid metabolism disorders. This article aimed to provide an overview of recent advances in understanding white fat browning and the role of BAT in lipid metabolism.  相似文献   
1000.
Gonadotropin-inhibitory hormone (GnIH) is a reproductive inhibitor and an endogenous orexigenic neuropeptide that may be involved in energy homeostasis and reproduction. However, whether GnIH is a molecular signal link of metabolism and the reproductive system, and thus, regulates reproductive activity as a function of the energy state, is still unknown. In the present study, we investigated the involvement of GnIH in glycolipid metabolism and reproduction in vivo, and in the coupling between these two processes in the testis level. Our results showed that chronic intraperitoneal injection of GnIH into male mice not only increased food intake and altered meal microstructure but also significantly elevated body mass due to the increased mass of liver and epididymal white adipose tissue (eWAT), despite the loss of testicular weight. Furthermore, chronic intraperitoneal administration of GnIH to male mice resulted in obesity-related glycolipid metabolic derangements, showing hyperlipidemia, hyperglycemia, glucose intolerance, and insulin resistance through changes in the expression of glucose and lipid metabolism-related genes in the pancreas and eWAT, respectively. Interestingly, the expression of GnIH and GPR147 was markedly increased in the testis of mice under conditions of energy imbalance, such as fasting, acute hypoglycemia, and hyperglycemia. In addition, chronic GnIH injection markedly inhibited glucose and lipid metabolism of mice testis while significantly decreasing testosterone synthesis and sperm quality, inducing hypogonadism. These observations indicated that orexigenic GnIH triggers hyperphagia-induced obesity-related metabolic derangements and hypogonadism in male mice, suggesting that GnIH is an emerging candidate for coupling metabolism and fertility by involvement in obesity and metabolic disorder-induced reproductive dysfunction of the testes.  相似文献   
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