44 resultados para GHS-R1a


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Loss of appetite in the medically ill and ageing populations is a major health problem and a significant symptom in cachexia syndromes, which is the loss of muscle and fat mass. Ghrelin is a gut-derived hormone which can stimulate appetite. Herein we describe a novel, simple, non-peptidic, 2-pyridone which acts as a selective agonist for the ghrelin receptor (GHS-R1a). The small 2-pyridone demonstrated clear agonistic activity in both transfected human cells and mouse hypothalamic cells with endogenous GHS-R1a receptor expression. In vivo tests with the hit compound showed significant increased food intake following peripheral administration, which highlights the potent orexigenic effect of this novel GHS-R1a receptor ligand.

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Bericht über eine Fragebogenerhebung bei Seniorstudierenden und regulär Studierenden an den Universitäten Magdeburg und Hannover im Sommersemester 2014. Darstellung und Interpretation der Ergebnisse vor dem Hintergrund aktueller Studien und Literatur zum Thema Bildung im Alter.

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Ghrelin was first identified in 1999 by Kojima and colleagues (Kojima et al. 1999) as the natural ligand of an orphan G-protein coupled receptor, the Growth Hormone (GH) secretagogue receptor (GHS-R), which had been identified several years earlier through the actions of a growing number of synthetic growth hormone releasing peptides (GHRPs) and non-peptidyl GH secretagogues (Howard et al. 1996). Early studies, therefore, focussed on the actions of ghrelin as an important regulator of GH secretion. As a result Kojima et al (1999) designated this GH-releasing peptide, ghrelin (ghre is the Proto-Indo-European root of the word 'grow'). We now recognise that the functions of ghrelin extend well beyond its GH releasing actions and that it is a multi-functional peptide with both endocrine and autocrine/paracrine modes of action.

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Invited book review of Carolyn Carpan, 2009, Sisters, Schoolgirls and Sleuths : Girls' Series Books in America, MD: Scarecrow Press

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This article analyzes a series of stories and artworks that were produced in a collective biography workshop. It explores Judith Butler’s concept of the heterosexual matrix combined with a Deleuzian theoretical framework. The article begins with an overview of Butler’s concept of the heterosexual matrix and her theorizations on how it might be disrupted. It then suggests how a Deleuzian framework offers other tools for analyzing these ruptures at the micro level of girls’ everyday interactions.

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Using a collective biography method informed by a Deleuzian theoretical approach (Davies and Gannon 2009, 2012), this article analyses embodied memories of girlhood becomings through affective engagements with resonating images in media and popular culture. In this approach to analysis we move beyond the impasse in some feminist cultural studies where studies of popular culture have been understood through theories of representation and reception that retain a sense of discrete subjectivity and linear effects. In these approaches, analysis focuses respectively on decoding and deciphering images in terms of their normative and ideological baggage, and, particularly with moving images, on psychological readings. Understanding bodies and popular culture through Deleuzian notions of “becoming” and “assemblage” opens possibilities for feminist researchers to consider the ways in which bodies are not separate from images but are, rather, becomings that are known, felt, materialized and mobilized with/through images(Coleman 2008a, 2008b, 2008c, 2009, 2011; Ringrose and Coleman 2013). We tease out the implications of this new approach to media affects through three memories of girls’ engagements with media images, reconceived as moments of embodied being within affective flows of popular culture that might momentarily extend upon ways of being and doing girlhood.

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通常的气体动力学方法,当气体分子的平均自由程与流场特征长度相比不可忽略时,不再适用,要采用稀薄气体动力学的方法。这适用于航天飞行器在高空飞行时受的力和热,也适用于微机电系统和真空系统等离子体材料加工等21世纪技术前沿领域。本书系统、简明地阐述稀薄气体动力学方法,给出方法的基础并着重介绍直接模拟Monte Carlo(DSMC)方法以及与低速稀薄气体流动相关的前沿课题。全书共分7章。前两章是作为学科的基础引入的,第1章以空气为对象对于分子能态结构、能态分布以极小篇幅作了简要概括的叙述,以作为了解稀薄气流非平衡现象物理基础的初步。第2章对包括双体碰撞、Boltzmann方程以及气体的平衡态等分子动理论的基础做了必要的讨论,其中包括了对唯像论分子相互作用模型、变径硬球(VHS)、变径软球(VSS)和概括化硬球(GHS)等模型的介绍。第3章讨论了各种分子和表面的相互作用模型,包括反映细致平衡的互易原理和基于此原理的CLL模型的阐述。第4章讨论自由分子流。第5章讨论应用于滑流领域的各连续介质方程及滑流边界条件,一些简单解以及热泳问题。第6章则较全面、概括地介绍了求解过程领域中的各种解析和数值方法。第7章介绍了直接模拟Monte Carlo(DSMC)方法,讨论了非平衡流动及低速稀薄流动等前沿课题,包括处理内能松弛、化学反应的方法、用于复杂流场通用软件的方法、低速稀薄流动的信息保存(IP)方法等。  本书适合高等学校力学一航空航天专业高年级学生、研究生及从事气动力学和航天研究的科研人员参考阅读。

编辑推荐

通常的气体动力学方法,当气体分子的平均自由程与流场特征长度相比不可忽略时,不再适用,要采用稀薄气体动力学的方法。这适用于航天飞行器在高空飞行时受的力和热,也适用于微机电系统和真空系统等离子体材料加工等21世纪技术前沿领域。本书系统、简明地阐述稀薄气体动力学方法,给出方法的基础并着重介绍直接模拟Monte Carlo(DSMC)方法以及与低速稀薄气体流动相关的前沿课题。

目录

符号表
绪论
第1节 稀薄气体动力学的提出
第2节 气体的分子模型
第3节 分子平均自由程
第4节 流动的领域划分
第5节 非平衡现象与稀薄气体动力学
第6节 相似准则
第1章 分子结构与能态
第1节 双原子分子
第2节 分子的能态分布
第3节 分子的内能、内自由度和内能分布函数
第2章 分子动理论基础
第1节 速度分布函数
第2节 宏观量的表达
第3节 分子的双体碰撞模型
第4节 碰撞截面与分子模型
第5节 Boltzmann方程
第6节 碰撞积分与气体分子的总碰撞数
第7节 碰撞积分的计算
第8节 Maxwell输运方程——矩方程
第9节 Maxwell分布
第10节 气体的平衡态
第11节 8速度气体模型
第12节 混合气体
第3章 分子表面相互作用
第1节 引言
第2节 镜面反射与漫反射,适应系数
第3节 互易性原理
第4节 CLL分子表面相互作用模型
第4章 自由分子流
第1节 气体中的分子数目通量和动量通量
第2节 作用于物体的气动力
第3节 表面元素的热传导
第4节 自由分子流出与热流逸
第5节 Couette流动与平板间的传热问题
第6节 无碰撞Boltzmann方程的通解,非定常流动
第5章 连续介质模型
第1节 引言
第2节 基本方程
第3节 滑流边界条件
第4节 一些简单问题的求解
第5节 热蠕动与热泳
第6章 过渡领域
第1节 概述
第2节 线化的BoltzmanN方程
第3节 矩方法
第4节 模型方程
第5节 有限差分法
第6节 间断纵坐标方法
第7节 积分方法
第8节 直接模拟方法
第7章 直接模拟Monte方法
第1节 引言
第2节 碰撞的取样
第3节 DSMC方法求解问题实例
第4节 内能的激发与松弛
第5节 化学反应的模拟
第6节 复杂流场的计算,位置元方法
第7节 微尺度低速气体流动,信息保存法
附录I 气体的性质和分子性质
附录II 分布函数求矩遇到的积分
附录III 具有给定分布的随机数的取样
附录IV Couette问题程序
参考文献
主题词索引

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A propriedade de auto-cura, em redes inteligente de distribuição de energia elétrica, consiste em encontrar uma proposta de reconfiguração do sistema de distribuição com o objetivo de recuperar parcial ou totalmente o fornecimento de energia aos clientes da rede, na ocorrência de uma falha na rede que comprometa o fornecimento. A busca por uma solução satisfatória é um problema combinacional cuja complexidade está ligada ao tamanho da rede. Um método de busca exaustiva se torna um processo muito demorado e muitas vezes computacionalmente inviável. Para superar essa dificuldade, pode-se basear nas técnicas de geração de árvores de extensão mínima do grafo, representando a rede de distribuição. Porém, a maioria dos estudos encontrados nesta área são implementações centralizadas, onde proposta de reconfiguração é obtida por um sistema de supervisão central. Nesta dissertação, propõe-se uma implementação distribuída, onde cada chave da rede colabora na elaboração da proposta de reconfiguração. A solução descentralizada busca uma redução no tempo de reconfiguração da rede em caso de falhas simples ou múltiplas, aumentando assim a inteligência da rede. Para isso, o algoritmo distribuído GHS é utilizado como base na elaboração de uma solução de auto-cura a ser embarcada nos elementos processadores que compõem as chaves de comutação das linhas da rede inteligente de distribuição. A solução proposta é implementada utilizando robôs como unidades de processamento que se comunicam via uma mesma rede, constituindo assim um ambiente de processamento distribuído. Os diferentes estudos de casos testados mostram que, para redes inteligentes de distribuição compostas por um único alimentador, a solução proposta obteve sucesso na reconfiguração da rede, indiferentemente do número de falhas simultâneas. Na implementação proposta, o tempo de reconfiguração da rede não depende do número de linhas nela incluídas. A implementação apresentou resultados de custo de comunicação e tempo dentro dos limites teóricos estabelecidos pelo algoritmo GHS.

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植物耐受和积累重金属的细胞学基础是植物细胞内存在一些能够络合和区隔化金属离子的机制。细胞中络合重金属离子最重要的小肽分子是谷胱甘肽(GSH)和植物络合素(PCs),而YCFⅠ基因编码的ABC-type 液泡膜转运蛋白负责将重金属离子及其与上述小肽形成的复合物转运进入细胞液泡中,即将重金属离子区隔化。植物细胞中合成GSH 和PCs 的关键酶分别是γ-谷氨酰氨半胱氨酸合成酶(GSHⅠ)和植物络合素合酶(PCS),他们的编码基因分别为GSHⅠ 和PCS 。此外定位于细胞质中的小囊泡上且对二价阳离子的吸收和转运有重要作用的SMF2 蛋白可能也参与重金属离子的区隔化过程。 为了改良植物使之能够应用于清除土壤中的重金属污染,本研究基于植物耐受和积累重金属的细胞学机制,分别将酿酒酵母来源的GSHⅠ、YCFⅠ和SMF2 基因,以及GSHⅠ、YCFⅠ基因分别与镉抗性植物大蒜来源的AsPCSⅠ 基因构建为不同的基因组合表达载体,转化模式植物拟南芥。对不同组合转基因拟南芥的功能分析表明: 1、酵母来源的基因GHSⅠ、YCFⅠ分别在拟南芥中异源超表达可以在一定程度上提高转基因拟南芥耐受、积累重金属的能力;其中GSHⅠ基因在拟南芥超表达可以提高转基因拟南芥合成GSH 的能力,转基因拟南芥细胞中GSH 浓度比野生型增加。 2、将GSHⅠ基因和来自大蒜的AsPCSⅠ基因同时在拟南芥中超表达能够显著提高转基因拟南芥耐受和积累重金属的能力,且积累和耐受能力显著高于分别转GSHⅠ或AsPCSⅠ的单价转基因株系;将YCFⅠ基因和AsPCSⅠ基因同时在拟南芥中超表达也能够显著提高转基因拟南芥耐受和积累重金属的能力,且积累和耐受能力显著高于分别转YCFⅠ或AsPCSⅠ的单价转基因株系。两种双价转基因株系GSHⅠ+AsPCSⅠ和YCFⅠ+AsPCSⅠ在积累和耐受不同重金属胁迫方面没有明显差别。 3、将SMF2 基因在拟南芥中异源表达,研究了植物中囊泡转运是否参与了重金属离子的吸收和区隔化过程。研究结果表明:超表达SMF2 基因的拟南芥尽管耐受重金属胁迫的能力与野生型没有明显差异,但其积累重金属的能力显著提高。这为证明植物中小囊泡转运参与重金属转运提供了间接证据。 综上所述,同时将多个参与植物对重金属络合、转运和区隔化作用的关键基因在转基因植物中表达可以提高植物耐受和积累重金属的能力,是培育可用于植物修复的新型工程植物的值得探索的途径。本论文所设计和构建的双价基因组合及其对目标植物的转化,在环境重金属污染的清除中有潜在的应用价值。

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Thermally induced evolution of phase transformations is a basic physical-chemical process in the dissociation of gas hydrate in sediment (GHS). Heat transfer leads to the weakening of the bed soil and the simultaneous establishment of a time varying stress field accompanied by seepage of fluids and deformation of the soil. As a consequence, ground failure could occur causing engineering damage or/and environmental disaster. This paper presents a simplified analysis of the thermal process by assuming that thermal conduction can be decoupled from the flow and deformation process. It is further assumed that phase transformations take place instantaneously. Analytical and numerical results are given for several examples of simplified geometry. Experiments using Tetra-hydro-furan hydrate sediments were carried out in our laboratory to check the theory. By comparison, the theoretical, numerical and experimental results on the evolution of dissociation fronts and temperature in the sediment are found to be in good agreement.

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Growth hormone (GH), prolactin (PRL) and somatolactin (SL) were purified simultaneously under alkaline condition (pH 9.0) from pituitary glands of sea perch (Lateolabrax japonicas) by a two-step procedure involving gel filtration on Sephadex G-100 and reverse-phase high-performance liquid chromatography (rpHPLC). At each step of purification, fractions were monitored by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and by immunoblotting with chum salmon GH. PRL and SL antisera. The yields of sea perch GH, PRL and SL were 4.2, 1.0 and 0.28 mg/g wet tissue, respectively. The molecular weights of 19,200 and 20,370 Da were estimated by SDS-PAGE for sea perch GH and PRL, respectively. Two forms of sea perch SL were found: one (28,400 Da) is probably glycosylated, while the other one (23,200 Da) is believed to be deglycosylated. GH bioactivity was examined by an in vivo assay. Intraperitoneal injection of sea perch GH at a dose of 0.01 and 0.1 mug/g body weight at 7-day intervals resulted in a significant increase in body weight and length of juvenile rainbow trout. The complete sea-perch GH amino acid sequence of 187 residues was determined by sequencing fragments cleaved by chemicals and enzymes. Alignment of sea-perch GH with those of other fish GHs revealed that sea-perch GH is most similar to advanced marine fish, such as tuna, gilthead sea bream, yellowfin porgy, red sea bream, bonito and yellow tail with 98.4, 96.2%, 95.7%, 95.2%, 94.1% and 91% sequence identity, respectively. Sea-perch GH has low identity to Atlantic cod (76.5%), hardtail (73.3%), flounder (68.4%), chum salmon (66.3%), carp (54%) and blue shark (38%). Partial amino-acid sequences of 127 of sea-perch PRL and the N-terminal of 16 amino-acid sequence of sea-perch SL have been determined. The data show that sea-perch PRL has a slightly higher sequence identity with tilapia PRL( 73.2%) than with chum salmon PRL(70%) in this 127 amino-acid sequence. (C) 2001 Elsevier Science B.V. All rights reserved.

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Phthalates are suspected to be endocrine disruptors. Di(2-ethylhexyl) phthalate (DEHP) is assumed to have low dermal absorption; however, previous in vitro skin permeation studies have shown large permeation differences. Our aims were to determine DEHP permeation parameters and assess extent of skin DEHP metabolism among workers highly exposed to these lipophilic, low volatile substances. Surgically removed skin from patients undergoing abdominoplasty was immediately dermatomed (800 μm) and mounted on flow-through diffusion cells (1.77 cm(2)) operating at 32°C with cell culture media (aqueous solution) as the reservoir liquid. The cells were dosed either with neat DEHP or emulsified in aqueous solution (166 μg/ml). Samples were analysed by HPLC-MS/MS. DEHP permeated human viable skin only as the metabolite MEHP (100%) after 8h of exposure. Human skin was able to further oxidize MEHP to 5-oxo-MEHP. Neat DEHP applied to the skin hardly permeated skin while the aqueous solution readily permeated skin measured in both cases as concentration of MEHP in the receptor liquid. DEHP pass through human skin, detected as MEHP only when emulsified in aqueous solution, and to a far lesser degree when applied neat to the skin. Using results from older in vitro skin permeation studies with non-viable skin may underestimate skin exposures. Our results are in overall agreement with newer phthalate skin permeation studies.

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