1,721,025 research outputs found
Influence of physical activity on structure and function of the RyR1 calcium channel: A systematic review
No full textINTRODUCTION: Calcium release through ryanodine receptor type 1 (RyR1) channel triggers skeletal muscle contraction, which is finely regulated during physical activity allowing muscles to adapt to stress. However, both prolonged physical activity and inactivity decrease contractile function. The adaptive mechanisms are related to changes in structure, function, and expression of RyR1 channel. EVIDENCE ACQUISITION: The search on the effects of physical activities on RyR1 structure and function covered PubMed and Scopus databases from 2008 onward. The search term used was RyR1 combined with exercise, fatigue, exertional rhabdomyolysis, or aging. EVIDENCE SYNTHESIS: Physical activity induces RyR1 dynamic post-translational modifications, driven essentially by increased reactive oxygen and nitrogen species. RyR1 redox-dependent modifications increase channel activity, but impaired Ca2+ handling may lead to muscle fatigue. Furthermore, imbalance of redox equilibrium may induce RyR1 fragmentation. During exercise RyR1 is also hyperphosphorylated and dissociated from its stabilizing subunit calstabin1, resulting in “leaky” channels and decreased exercise tolerance. RyR1 modifications also occur during aging. Conversely, reduced RyR1 protein expression occurs in some pathophysiological conditions characterized by low-exercise capacity, i.e., heart failure and prolonged bed rest. Impaired muscle performance is also linked to RyR1 mutations, with altered channel structure and/or function. Moreover, in apparently healthy subjects with RyR1 mutations, physical exercise can trigger skeletal muscle stiffness at low temperatures, or exertional rhabdomyolysis. CONCLUSIONS: We provide an overview of the molecular aspects linking skeletal muscle activity to RyR1 modifications, with particular attention to the effects produced by different type of exercises, i.e. aerobic and anaerobic exercise, by some pathophysiological conditions, by age-related loss of muscle function and by RyR1 mutations
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
A Quantitative Polymerase Chain Reaction (PCR) Assay Completely Discriminates between Duchenne and Becker Muscular Dystrophy Deletion Carriers and Normal Females.
No full textA Quantitative Polymerase Chain Reaction (PCR) Assay Completely Discriminates between Duchenne and Becker Muscular Dystrophy Deletion Carriers and Normal Females.
No full textA Quantitative Polymerase Chain Reaction (PCR) Assay Completely Discriminates between Duchenne and Becker Muscular Dystrophy Deletion Carriers and Normal Females.
No full text
Novel deletion at the M and P promoters of the human dystrophin gene associated with a Duchenne muscular dystrophy
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