1,721,436 research outputs found
Signaling pathways in failing human heart muscle cells
No full textExperimental studies have delineated important signaling pathways in cardiomyocytes and their alterations in heart failure; however, there is now evidence that these observations are not necessarily applicable to human cardiac muscle cells. For example, angiotensin II (A II) does not exert positive inotropic effects in human ventricular muscle cells, in contrast to observation in rats. Thus, it is important to elucidate cardiac signaling pathways in humans in order to appreciate the functional role of neurohumoral or mechanical stimulation in human myocardium in health and disease. In the present article, we review signal pathways in the failing human heart based on studies in human cardiac tissues and in vivo physiological studies related to A II, nitric oxide, and beta-adrenergic simulation. (C) 1997, Elsevier Science Inc
PATHOPHYSIOLOGY AND TREATMENT OF CONGESTIVE-HEART-FAILURE
No full textPharmacotherapy of heart failure is likely to be most efficacious when individually tailored to the prevailing pathophysiological derangements. Their diagnostic definition and understanding of the mechanisms involved affords the greatest opportunity for their correction and retardation of further progression of the syndrome, together with related improvements in quality of life, reduction of morbid cardiovascular events and improvement in prognosis. Four approaches may be identified, each of which allows rational therapeutic intervention. The disordered contractile geometry of the failing ventricle gives rise to increased ventricular wall tension and myocardial hypertrophy. The phenotype change largely responsible for this progression may be retarded, halted, or even reversed by a reduction of the elevated ventricular pressure and volume induced by diuresis and/or systemic vasodilatation. Knowledge of the subcellular changes responsible for electromechanical coupling and subsequent myocardial cell contraction in the various stages of heart failure is still incomplete. Pharmacotherapeutic interventions with positive inotropic agents have not been universally clinically efficacious, though the digitalis glycosides and, more recently, drugs that increase the sensitivity of the contractile proteins to calcium appear to afford further opportunity as they do not increase myocardial energy expenditure. In this regard, reduction in heart rate is a major determinant of myocardial contractile performance. Vascular stiffness and reduced vasodilator capacity are intrinsic accompaniments of congestive heart failure and exert deleterious effects on the heart by increasing preload and afterload and on the regional circulations by reducing blood flow. The mechanisms responsible include increased activity of the sympathoadrenal and renin-angiotensin-aldosterone systems, as well as reduction of endothelium-derived relaxing factor and increased stiffness of the vascular walt due to oedema. These furnish important targets for vasodilator acid diuretic therapy and specific interventions to correct endothelial dysfunction. There are marked morphological and functional alterations of skeletal muscle depending on the severity and duration of the heart failure. These changes, together with activity detraining, contribute to reduced exercise capacity, a primary clinical hallmark of the syndrome. Improvement in muscle blood flow by improvement in cardiac pumping function and vasodilatation of the systemic resistance vessels, together with physical training programmes, constitute the most rational therapeutic approach to this fourth feature of the syndrome of congestive heart failure
BEVAST-EWL - Skala zu studentischen Besorgtheits-, Vermeidungs- und Aufgeregtheitskognitionen bezüglich statistischer Anforderungen in erziehungswissenschaftlichen Lehr-Lern-Kontexten - Scale for Measuring Education Science Students' Worry, Avoidance, and Emotionality Cognitions Encountering Statistical Demands
No full textFaber G, Drexler H, Stappert A. BEVAST-EWL - Skala zu studentischen Besorgtheits-, Vermeidungs- und Aufgeregtheitskognitionen bezüglich statistischer Anforderungen in erziehungswissenschaftlichen Lehr-Lern-Kontexten - Scale for Measuring Education Science Students' Worry, Avoidance, and Emotionality Cognitions Encountering Statistical Demands. ZPID (Leibniz Institute for Psychology) – Open Test Archive; 2018
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
Infraschall und tieffrequenter Schall – ein Thema für den umweltbezogenen Gesundheitsschutz?!
No full textBeyer A, Dott W, Drexler H, et al. Infraschall und tieffrequenter Schall – ein Thema für den umweltbezogenen Gesundheitsschutz?!. Bundesgesundheitsbl. Gesundheitsforsch. Gesundheitsschutz. 2007;50(12):1582-1589
- …
