1,720,983 research outputs found
Cis-interaction of ligands on a supported lipid bilayer affects their binding to cell adhesion receptors
No full textCell adhesion on a supported lipid bilayer (SLB) functionalized with ligand proteins is a widely-used cell-mimetic model for the study of the trans receptor-ligand interaction that mediates the adhesion, and has been shown to play an important role in unravelling the molecular players in cell adhesion. Experimental studies of such cell-SLB adhesion systems often assume that there is no cis interactions between the ligands. An important question remains whether the cis-interaction affects the trans receptor-ligand interaction. Using a statistical-mechanical model and Monte Carlo simulations with biologically relevant parameters, we find that the attractive cis-interaction of strength 1 k(B)T between adjacent ligands on the SLB can lead to an amplification of both the affinity and cooperativity of the receptor-ligand binding, thereby facilitating the phase separation within the adhering cell membrane. In contrast, the adhesion system is less sensitive to the repulsive cis-interaction between adjacent ligands on the SLB. Our results suggest that the ligand-ligand cis-interaction should be carefully considered in the cell-SLB adhesion experiments
Interplay Between Receptor-Ligand Binding and Lipid Domain Formation Depends on the Mobility of Ligands in Cell-Substrate Adhesion
No full textCell-cell adhesion and the adhesion of cells to extracellular matrix are mediated by the specific binding of receptors on the cell membrane to their cognate ligands on the opposing surface. The adhesion receptors can exhibit affinity for nanoscale lipid clusters that form in the cell membrane. Experimental studies of such adhesion systems often involve a cell adhering either to a solid surface with immobile ligands or a supported lipid bilayer with mobile ligands. A central question in these cell-substrate adhesions is how the mobility of the ligands physically affects their binding to the adhesion receptors and thereby the behavior of the nanoscale lipid clusters associated with the receptors. Using a statistical mechanical model and Monte Carlo simulations for the adhesion of cells to substrates with ligands, we find that, for mobile ligands, binding to adhesion receptors can promote the formation of mesoscale lipid domains, which in turn enhances the receptor-ligand binding. However, in the case of immobile ligands, the receptor-ligand binding and the tendency for the nanoscale lipid clusters to further coalesce depend on the distribution of the ligands on the substrate. Our findings help to explain why different adhesion experiments for identifying the interplay between receptor-ligand binding and heterogeneities in cell membranes led to contradictory results
High energy density in poly(vinylidene fluoride-trifluoroethylene) composite incorporated with modified halloysite nanotubular architecture
No full textDielectric polymer capacitors with high power density as well as efficient charge-discharge rate are widely investigated in past decades. The development of polymer film with large electric capability has become the research topic for the energy storage of advanced power equipment. Here the tubular architecture in poly(vinylidene fluoridetrifluoroethylene) (P(VDF-TrFE)) composite film has been constructed with modified halloysite nanotubes (HNTs) to accomplish an effective diffusion of matter and energy units under high electric field. The nanotube surface was functionalized with poly(dopamine) (PDA) in tris-buffer solution to improve the compatibility with fluoropolymer. The energy capability of P(VDF-TrFE) composite film is enhanced owing to the large content of electroactive phase and interfacial polarization. The dielectric constant in 4 wt% PDA-HNTs/P(VDF-TrFE) film is 34.1 at 100 Hz, and the energy density in 2 wt% composite achieves 5.6 J/cm3 with charge-discharge efficiency of 74% at 250 MV/m based on the efficient transportation of ions within hollow nanotubular structure. This work delivers a simple method to construct the efficient diffusion route in polymer dielectrics for film capacitor with high energy density and cycle efficiency
Cuffless Blood Pressure Monitoring: Academic Insights and Perspectives Analysis
No full textIn recent decades, cuffless blood pressure monitoring technology has been a point of research in the field of health monitoring and public media. Based on the web of science database, this paper evaluated the publications in the field from 1990 to 2020 using bibliometric analysis, described the developments in recent years, and presented future research prospects in the field. Through the comparative analysis of keywords, citations, H-index, journals, research institutions, national authors and reviews, this paper identified research hotspots and future research trends in the field of cuffless blood pressure monitoring. From the results of the bibliometric analysis, innovative methods such as machine learning technologies related to pulse transmit time and pulse wave analysis have been widely applied in blood pressure monitoring. The 2091 articles related to cuffless blood pressure monitoring technology were published in 1131 journals. In the future, improving the accuracy of monitoring to meet the international medical blood pressure standards, and achieving portability and miniaturization will remain the development goals of cuffless blood pressure measurement technology. The application of flexible electronics and machine learning strategy in the field will be two major development directions to guide the practical applications of cuffless blood pressure monitoring technology
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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