171 resultados para EPO


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用WAXD、TBA、DSC等方法对PP/EPO共混体系的结晶结构和相容性进行了研究。WAXD方法测定表明PP/EPO共混体系的结晶度随EPO组份含量的增加而降低,晶胞参数值与组份比无关,使用Hosemann次晶模型法计算了此体系的第二类晶格畸变和应力畸变,表明衍射峰的宽化主要是由第二类晶格畸变引起的。根据DSC和TBA实验得出在所有组成PP/EPO共混体系是不相容的,但在非晶区可能部分相容。采用WAXD、DDV、DSC等方法对LDPE/EPO共混体系的结晶结构和相容性进行了研究,用Ruland方法计算的结晶度值随EPO组份含量的增加而降低,晶胞参数值与组份比无关。使用方差——范围函数方法计算了LDPE/EPO共混体系的(110)和(200)晶面的微晶大小(L_(hkL))和晶格畸变参数(g_t)。L_(hkL)和g_t值随EPO组份的增加而下降。从DDV-II粘弹谱仪测得的共混体系的谱图可看出,在β松驰附近,EPO的β转变随LDPE的加入量增加向低温方向移动,这是由于渗透到EPO非晶中的LDPE非晶部分影响了EPO链段运动所致。从LDPE/EPO共混体系的DSC图谱可知,只存在一个熔融峰,这说明很可能LDPE与EPO形成了共晶,从共混物的Tm、Tc可知,随EPO组份增加,熔点下降,结晶温度下降,纯EPO显示出高于LDPE及共混物的Tm.WAXD法证明,这是由于EPO中PE长序列贡献的结果。为了进一步证实EPO中少量结晶相与LDPE中晶相形成了共晶,我们做了萃取实验,结果表明了共晶的存在。由于各种聚乙烯的非晶相间是任意混容的,大部分为非晶部分的EPO中少量结晶相又与LDPE的结晶相形成了共晶,因盯LDPE/EPO是相容的共混体系。用DSC方法研究了LDPE/EPO共混体系的结晶动力学,对LDPE/EPO共混体系的等温结晶动力学研究表明,共混物是三维生长的异相成核。共混体系的平衡熔点随EPO含量的增加而降低,采用Lauritzen提出的Z判断方法,得出共混体系在各个结晶温度下的结晶过程都是以方式(II)进行的。采用Avrami方程和Ozawa方程的新的处理非等温结晶动力学的方程,研究了LDPE/EPO共混体系的非等温结晶动力学,得到了描述非等温结晶过程的一些基本参数。

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用DSC方法研究了LDPE/EPO共混体系的等温及非等温结晶动力学,对LDPE/EPO共混体系的等温结晶动力学研究表明,共混物是三维生长的异相成核,共混物在各个结晶温度下的结晶过程都是以方式K_g(Ⅱ)进行的.采用联系Avrami方程和Ozawa方程导出的新非等温结晶动力学方程,处理了LDPE/EPO共混体系,得到了非等温结晶过程的一些基本参数,新方程很好地描述了此共混体系的非等温结晶动力学过程.

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DDV、DSC、WAXD、萃取和Raman光谱实验表明,在所有组成下,LDPE/EPO共混体系共晶相容.WAXD法测定表明,LDPE/EPO共混体系的结晶度随EPO组分含量的增加而降低,EPO未能进入LDPE晶胞中.

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WAXD方法测定表明PP/EPO共混体系的结晶度随EPO组份含量的增加而降低,晶胞参数与组份比无关,并计算了第二类晶格畸变。根据PP/EPO的DSC和扭辫实验得出在所有组成下PP/EPO共混体系是不相容的。但在非晶区可能部分相容。

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Abstract The role and regulation of the pleiotropic cytokine erythropoietin (EPO) in skeletal muscle are controversial. EPO exerts its effects by binding its specific receptor (EPO-R), which activates intracellular signaling and gene transcription in response to internal and external stress signals. EPO is suggested to play a direct role in myogenesis via the EPO-R, but several studies have questioned the effect of EPO treatment in muscle in vitro and in vivo. The lack of certainty surrounding the use of nonspecific EPO-R antibodies contributes to the ambiguity of the field. Our study demonstrates that the EPO-R gene and protein are expressed at each stage of mouse C2C12 and human skeletal muscle cell proliferation and differentiation and validates a specific antibody for the detection of the EPO-R protein. However, in our experimental conditions, EPO treatment had no effect on mouse C2C12 and human muscle cell proliferation, differentiation, protein synthesis or EPO-R expression. While an increase in Akt and MAPK phosphorylation was observed, we demonstrate that this effect resulted from the stress caused by changing medium and not from EPO treatment. We therefore suggest that skeletal muscle EPO-R might be present in a nonfunctional form, or too lowly expressed to play a role in muscle cell function.

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Erythropoietin (EPO) primarily activates erythroid cell proliferation and growth and is active in several types of non-hematopoietic cells via its interaction with the EPO-receptor (EPO-R). This review focuses on the role of EPO in skeletal muscle. The EPO-R is expressed in skeletal muscle cells and EPO may promote myoblast differentiation and survival via the activation of the same signaling cascades as in hematopoietic cells, such as STAT5, MAPK and Akt. Inconsistent results exist with respect to the detection of the EPO-R mRNA and protein in muscle cells, tissue and across species and the use of non-specific EPO-R antibodies contributes to this problem. Additionally, the inability to reproducibly detect an activation of the known EPO-induced signaling pathways in skeletal muscle questions the functionality of the EPO-R in muscle in vivo. These equivocal findings make it difficult to distinguish between a direct effect of EPO on skeletal muscle, via the activation of its receptor, and an indirect effect resulting from a better oxygen supply to the muscle. Consequently, the precise role of EPO in skeletal muscle and its regulatory mechanism/s remain to be elucidated. Further studies are required to comprehensively establish the importance of EPO and its function in skeletal muscle health.

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Drawing upon Brazilian experience, this research explores some of the key issues to be addressed in using e-government technical cooperation designed to enhance service provision of Patent Offices in developing countries. While the development of software applications is often seen merely as a technical engineering exercise, localization and adaptation are context bounded matters that are characterized by many entanglements of human and non-humans. In this work, technical, legal and policy implications of technical cooperation are also discussed in a complex and dynamic implementation environment characterized by the influence of powerful hidden agendas associated with the arena of intellectual property (IP), which are shaped by recent technological, economic and social developments in our current knowledge-based economy. This research employs two different theoretical lenses to examine the same case, which consists of transfer of a Patent Management System (PMS) from the European Patent Office (EPO) to the Brazilian Patent Office that is locally named ‘Instituto Nacional da Propriedade Industrial’ (INPI). Fundamentally, we have opted for a multi-paper thesis comprising an introduction, three scientific articles and a concluding chapter that discusses and compares the insights obtained from each article. The first article is dedicated to present an extensive literature review on e-government and technology transfer. This review allowed the proposition on an integrative meta-model of e-government technology transfer, which is named E-government Transfer Model (ETM). Subsequently, in the second article, we present Actor-Network Theory (ANT) as a framework for understanding the processes of transferring e-government technologies from Patent Offices in developed countries to Patent Offices in developing countries. Overall, ANT is seen as having a potentially wide area of application and being a promising theoretical vehicle in IS research to carry out a social analysis of messy and heterogeneous processes that drive technical change. Drawing particularly on the works of Bruno Latour, Michel Callon and John Law, this work applies this theory to a longitudinal study of the management information systems supporting the Brazilian Patent Office restructuration plan that involved the implementation of a European Patent Management System in Brazil. Based upon the ANT elements, we follow the actors to identify and understand patterns of group formation associated with the technical cooperation between the Brazilian Patent Office (INPI) and the European Patent Office (EPO). Therefore, this research explores the intricate relationships and interactions between human and non-human actors in their attempts to construct various network alliances, thereby demonstrating that technologies embodies compromise. Finally, the third article applies ETM model as a heuristic frame to examine the same case previously studied from an ANT perspective. We have found evidence that ETM has strong heuristic qualities that can guide practitioners who are engaged in the transfer of e-government systems from developed to developing countries. The successful implementation of e-government projects in developing countries is important to stimulate economic growth and, as a result, we need to understand the processes through which such projects are being implemented and succeed. Here, we attempt to improve understanding on the development and stabilization of a complex social-technical system in the arena of intellectual property. Our preliminary findings suggest that e-government technology transfer is an inherently political process and that successful outcomes require continuous incremental actions and improvisations to address the ongoing issues as they emerge.

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[EN] This study was performed to test the hypothesis that administration of recombinant human erythropoietin (rHuEpo) in humans increases maximal oxygen consumption by augmenting the maximal oxygen carrying capacity of blood. Systemic and leg oxygen delivery and oxygen uptake were studied during exercise in eight subjects before and after 13 wk of rHuEpo treatment and after isovolemic hemodilution to the same hemoglobin concentration observed before the start of rHuEpo administration. At peak exercise, leg oxygen delivery was increased from 1,777.0+/-102.0 ml/min before rHuEpo treatment to 2,079.8+/-120.7 ml/min after treatment. After hemodilution, oxygen delivery was decreased to the pretreatment value (1,710.3+/-138.1 ml/min). Fractional leg arterial oxygen extraction was unaffected at maximal exercise; hence, maximal leg oxygen uptake increased from 1,511.0+/-130.1 ml/min before treatment to 1,793.0+/-148.7 ml/min with rHuEpo and decreased after hemodilution to 1,428.0+/-111.6 ml/min. Pulmonary oxygen uptake at peak exercise increased from 3,950.0+/-160.7 before administration to 4,254.5+/-178.4 ml/min with rHuEpo and decreased to 4,059.0+/-161.1 ml/min with hemodilution (P=0.22, compared with values before rHuEpo treatment). Blood buffer capacity remained unaffected by rHuEpo treatment and hemodilution. The augmented hematocrit did not compromise peak cardiac output. In summary, in healthy humans, rHuEpo increases maximal oxygen consumption due to augmented systemic and muscular peak oxygen delivery.

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The present dataset contain source data for Figure 5a from Schilling et al., 2009. Cell fate decisions are regulated by the coordinated activation of signalling pathways such as the extracellular signal-regulated kinase (ERK) cascade, but contributions of individual kinase isoforms are mostly unknown. The authors combined quantitative data from erythropoietin-induced pathway activation in primary erythroid progenitor (colony-forming unit erythroid stage, CFU-E) cells with mathematical modelling, in order to predict and experimentally confirmed a distributive ERK phosphorylation mechanism in CFU-E cells. The authors found evidences that double-phosphorylated ERK1 attenuates proliferation beyond a certain activation level, whereas activated ERK2 enhances proliferation with saturation kinetics. Phosphorylation levels of JAK2 at 7 min after stimulation for Epo concentrations ranging from 0.1 to 1000 U/ml were simulated.

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The present dataset data contain source data for Figure 5a from Schilling et al., 2009. Cell fate decisions are regulated by the coordinated activation of signalling pathways such as the extracellular signal-regulated kinase (ERK) cascade, but contributions of individual kinase isoforms are mostly unknown. The authors combined quantitative data from erythropoietin-induced pathway activation in primary erythroid progenitor (colony-forming unit erythroid stage, CFU-E) cells with mathematical modelling, in order to predict and experimentally confirmed a distributive ERK phosphorylation mechanism in CFU-E cells. The authors found evidences that double-phosphorylated ERK1 attenuates proliferation beyond a certain activation level, whereas activated ERK2 enhances proliferation with saturation kinetics. CFU-E cells were stimulated with the indicated Epo concentrations for 7 min and phosphorylation levels were determined by quantitative immunoblotting.