1,720,962 research outputs found
HEPARAN-SULFATE FRACTIONS - PHARMACOLOGICAL PROPERTIES AND EFFECT ON SMOOTH-MUSCLE CELL-PROLIFERATION IN-VITRO
No full textIn this study we have evaluated the effect of heparan sulfate fractions with different molecular weights on the growth of aortic smooth muscle cells (SMC) of rat in vitro. These fractions were obtained from unfractionated heparan sulfate by a gel filtration technique. The fraction having a molecular weight of 25.5 kDa showed a significant antiproliferative activity only at higher concentrations, while the fractions with molecular weight ranging from 10.7 kDa to 6.8 kDa were effective in reducing cell proliferation at very low concentrations (10(-5) nM and 10(-4) nM). The dose-effect curves are characterized by an initial plateau followed by an increase in effectiveness at the highest concentration. The relationship between molecular weight and antiproliferative activity is discussed
INTERACTION OF HEPARAN-SULFATE AND ITS FRACTIONS WITH ENDOTHELIAL-CELLS IN CULTURE
No full textIn the present work we have investigated the binding capacity, to cell membrane of bovine aortic endothelial cells (BAEC) cultured in vitro, of heparan sulfate (Mr 11.1 kDa) and its four fractions named A (Mr 24.5 kDa), B (Mr 10.7 kDad), C (Mr 9.1 kDa) and D (Mr 6.8 kDa). Experiments were performed in comparison with unfractionated heparin (Mr 12.9 kDa). The binding of the examined compounds was determined by the degree of displacement of [H-3]-heparin from the cell membrane. The efficiency of heparan sulfate fractions B, C and D in displacing labelled heparin was found to decrease in function with the decrease of the molecular masses of the compounds, [H-3]-heparin could be efficiently displaced mainly by heparin and fraction A, the fraction which has the highest molecular weight and represents only 3.8% of the unfractionated HA 90681. These experimental results may confirm that molecular mass is an important feature for the interaction of glycosaminoglycans with the specific binding sites on the cell surface
Cell-matrix interactions in cultured dermal fibroblasts from patients with an inherited connective-tissue disorder
No full textIndirect-immunofluorescence studies were performed on cultured dermal fibroblasts from patients with Pseudoxanthoma Elasticum (PXE), an inherited connective-tissue disorder the pathogenesis of which is still unknown. Apparent abnormalities of cytoskeletal structures were revealed by using phalloidin and specific antibodies to alfa-smooth muscle actin and to vimentin. Altered expression of integrin receptors for different extracellular matrix components seems to be present in the pathological cells as preliminary data suggest by using antibodies against alfa subunits of integrins. This study was designed to test the presence of abnormal cell-matrix interactions responsible for the clinical features and involved in the pathogenesis of the PXE disease
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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