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1.
采用自行设计的两种不同结构的熔融浸渍模具制备了连续玻璃纤维增强聚丙烯预浸带,测试了模具结构对预浸带的孔隙率、纤维断裂率、界面形貌、纤维分散均匀度和拉伸强度的影响,建立了纤维浸渍模型和纤维断裂模型,并通过理论模型对预浸带的孔隙率和断裂率进行理论预测。结果表明,本文建立的数学模型能够有效预测预浸带的浸渍程度和纤维断裂率,可用于浸渍模具结构的优化设计;在本文范围内,与波浪形模具相比,斜齿形模具的多楔形区结构可以有效地降低预浸带孔隙率和提升纤维分散程度;波浪形模具的流道圆角半径较大,楔形区个数较少,与斜齿形模具相比,可有效降低纤维断裂率并提升拉伸性能。 相似文献
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Beatriz E. Nielsen Teresa Minguez Isabel Bermudez Cecilia Bouzat 《Cellular and molecular life sciences : CMLS》2018,75(13):2457-2471
The α7 nicotinic receptor is a promising drug target for neurological and inflammatory disorders. Although it is the homomeric member of the family, a novel α7β2 heteromeric receptor has been discovered. To decipher the functional contribution of the β2 subunit, we generated heteromeric receptors with fixed stoichiometry by two different approaches comprising concatenated and unlinked subunits. Receptors containing up to three β2 subunits are functional. As the number of β2 subunits increases in the pentameric arrangement, the durations of channel openings and activation episodes increase progressively probably due to decreased desensitization. The prolonged activation episodes conform the kinetic signature of α7β2 and may have an impact on neuronal excitability. For activation of α7β2 receptors, an α7/α7 binding-site interface is required, thus indicating that the three β2 subunits are located consecutively in the pentameric arrangement. α7-positive allosteric modulators (PAMs) are emerging as novel therapeutic drugs. The presence of β2 in the pentamer affects neither type II PAM potentiation nor activation by an allosteric agonist whereas it impairs type I PAM potentiation. This first single-channel study provides fundamental basis required to decipher the role and function of the novel α7β2 receptor and opens doors to develop selective therapeutic drugs. 相似文献
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Sei Yoshida Regina Pacitto Ken Inoki Joel Swanson 《Cellular and molecular life sciences : CMLS》2018,75(7):1227-1239
The growth and proliferation of metazoan cells are driven by cellular nutrient status and by extracellular growth factors. Growth factor receptors on cell surfaces initiate biochemical signals that increase anabolic metabolism and macropinocytosis, an actin-dependent endocytic process in which relatively large volumes of extracellular solutes and nutrients are internalized and delivered efficiently into lysosomes. Macropinocytosis is prominent in many kinds of cancer cells, and supports the growth of cells transformed by oncogenic K-Ras. Growth factor receptor signaling and the overall metabolic status of the cell are coordinated in the cytoplasm by the mechanistic target-of-rapamycin complex-1 (mTORC1), which positively regulates protein synthesis and negatively regulates molecular salvage pathways such as autophagy. mTORC1 is activated by two distinct Ras-related small GTPases, Rag and Rheb, which associate with lysosomal membranes inside the cell. Rag recruits mTORC1 to the lysosomal surface where Rheb directly binds to and activates mTORC1. Rag is activated by both lysosomal luminal and cytosolic amino acids; Rheb activation requires phosphoinositide 3-kinase, Akt, and the tuberous sclerosis complex-1/2. Signals for activation of Rag and Rheb converge at the lysosomal membrane, and several lines of evidence support the idea that growth factor-dependent endocytosis facilitates amino acid transfer into the lysosome leading to the activation of Rag. This review summarizes evidence that growth factor-stimulated macropinocytosis is essential for amino acid-dependent activation of mTORC1, and that increased solute accumulation by macropinocytosis in transformed cells supports unchecked cell growth. 相似文献
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Xiuli Liu 《系统科学与复杂性》2018,31(6):1554-1570
The paper established a double filtering method (DFM) to visualize the skeleton industrial structure (SIS) of one economy and find its evolution rule. Different with the previous researches, this method is from a new view of industrial conjunctions combined by leading sectors to depict the industrial structure. It was proved that the leading sector selected by DFM must be key sector selected by Hirschman-Rasmussen method. Applied DFM to input-output tables of China, Japan and USA and MFA to Japan and USA, the results analysis showed that DFM could overtake the two main shortcomings of minimum flow analysis (MFA), scratch SIS of each economy with its own characteristics, visualize the general evolution rules of the industrial structure with crisscrossed conjunctions among leading sectors. 相似文献
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In this article we consider the growing interest in recent years in the use of documentary strategies in the wold of contemporary art, film and performing arts and explore some of the central epistemological assumptions underpinning the persistent idea that the documentary should be equated with ‘non-fiction’. Following Stella Bruzzi we argue that if documentary theory maintains objectivity as the primary measure of value, it will inevitably and continuously arrive at the conclusion that the documentary genre is fundamentally flawed. Instead, we propose to move beyond the ‘realist epistemology’ of documentary theory and focus on the ‘documentary real’, i.e. the specific performativity of the reality constructed in and by the documentary genre. In the last paragraphs, we introduce the various articles that address the “documentary real” in this special issue. 相似文献
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Patricio Atanes Inmaculada Ruz-Maldonado Ross Hawkes Bo Liu Min Zhao Guo Cai Huang Israa Mohammed Al-Amily Albert Salehi Stefan Amisten Shanta J. Persaud 《Cellular and molecular life sciences : CMLS》2018,75(16):3039-3050