1,721,734 research outputs found
Molecular organization and assembly of the postsynaptic density of excitatory brain synapses.
No full textThe postsynaptic density (PSD) is a postsynaptic membrane specialization at excitatory synapses. The PSD is made of macromolecular multiprotein complexes, which contain a variety of synaptic proteins including membrane, scaffolding, and signaling proteins. By coaggregating with postsynaptic cell adhesion molecules, PSD proteins promote the formation and maturation of excitatory synapses. PSD proteins organize signaling pathways to coordinate structural and functional changes in synapses, and they regulate trafficking and recycling of glutamate receptors, which determines synaptic strength and plasticity. Synaptic activity dynamically regulates the assembly of the PSD through mechanisms including protein phosphorylation, palmitoylation, and protein degradation. PSD proteins associate with diverse motor proteins, suggesting that they function as adaptors linking motors to their specific cargoes
Clustering assay for studying the interaction of membrane proteins with PDZ domain proteins.
No full textSome membrane proteins must be clustered at target sites to efficiently perform their functions. PDZ domain-containing scaffold proteins bind to the tails of target membrane proteins and promote their localization and clustering on the cell surface. This chapter describes the experimental details of the clustering assay, using the interaction between potassium channels and PSD-95, an abundant PDZ domain protein in neuronal synapses, as a model
Analysis on the stirling-type pulse tube refrigerator in consideration of dynamics of linear compressor
No full textThis paper describes the performance analysis of Stirling-type pulse tube refrigerator (PTR) in conjunction with the dynamics of the accompanied linear compressor. The dynamic behavior of the piston in the linear compressor is directly influenced by the load condition of the PTR. In this paper, the dynamic equation of the piston is simultaneously solved with the thermo-hydraulic governing equations of the PTR using linear analysis model and the performance of the PTR is predicted with the accompanied thermal losses. The developed analysis code is verified with the experimental results. The effect of the inertance tube length which plays an important role in the PTR is also specifically investigated from the experimental and simulation results. It clearly shows the effect of the flow impedance of the inertance tube on the dynamic response of the piston as well as the cooling performance of the PTR. (C) 2007 Elsevier Ltd. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Hinge-bending motion of D-allose-binding protein from Escherichia coli - Three open conformations
No full textConformational changes of periplasmic binding proteins are essential for their function in chemotaxis and transport. The allose-binding protein from Escherichia coli is, like other receptors in its family, composed of two alpha/beta domains joined by a three-stranded hinge. In the previously determined structure of the closed, ligand-bound form (Chaudhuri, B. N., Ko, J., Park, C., Jones, T. A., and Mowbray, S. L. (1999) J. Mol. Biol. 286, 1519-1531), the ligand-binding site is buried between the two domains. We report here the structures of three distinct open, ligand-free forms of this receptor, one solved at 3.1-Angstrom resolution and two others at 1.7-Angstrom resolution. Together, these allow a description of the conformational changes associated with ligand binding. A few large, coupled torsional changes in the hinge strands are sufficient to generate the overall bending motion, with only minor disruption of the individual domains. Integral water molecules appear to act as structural "ball bearings" in this process. The conformational changes of the related ribose-binding protein follow a distinct pattern. The observed differences between the two proteins can be interpreted in the context of changes in sequence and in crystal packing and provide new insights into the nature of hinge bending motion in this class of periplasmic binding proteins
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