1,720,967 research outputs found
Middle age has a significant impact on gene expression during skin wound healing in male mice
No full textThe vast majority of research on the impact of age on skin wound healing (WH) compares old animals to young ones. The middle age is often ignored in biogerontological research despite the fact that many functions that decline in an age-dependent manner have starting points in mid-life. With this in mind, we examined gene expression patterns during skin WH in late middle-aged versus young adult male mice, using the head and back punch models. The rationale behind this study was that the impact of age would first be detectable at the transcriptional level. We pinpointed several pathways which were over-activated in the middle-aged mice, both in the intact skin and during WH. Among them were various metabolic, immune-inflammatory and growth-promoting pathways. These transcriptional changes were much more pronounced in the head than in the back. In summary, the middle age has a significant impact on gene expression in intact and healing skin. It seems that the head punch model is more sensitive to the effect of age than the back model, and we suggest that it should be more widely applied in aging research on wound healing
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
Die Rolle des Kallikrein-Kinin-Systems bei der fokalen zerebralen Ischämie
Full text linkDer ischämische Schlaganfall ist eine der häufigsten Ursachen für Mortalität und Behinderungen in der westlichen Welt – entsprechend nimmt die gesundheitliche und volkswirtschaftliche Bedeutung dieser Erkrankung einen hohen Stellenwert ein.
Eine große Anzahl experimenteller und klinischer Studien befasste sich in den letzten Jahren mit verschiedenen Mechanismen zur Neuroprotektion, konnte aber die in der experimentellen Forschung erbrachten Ergebnisse in der Klinik nicht bestätigen.
Ziel dieser Arbeit war es daher, die therapeutische Wirkung der Blockade des Kallikrein-Kinin-Systems mittels Antagonisierung des Bradykinin B2-Rezeptors mit einem Nicht-Peptid Antagonisten in einem Tiermodell der temporären fokalen zerebralen Ischämie zu untersuchen und dabei seine prä- und postischämischen Effekte und möglichen Wirkmechanismen zu erforschen.
Unsere Ergebnisse bestätigen die durch B2-Rezeptor-Aktivierung vermittelte Mediatorfunktion des Kallikrein-Kinin-Systems bei der fokalen zerebralen Ischämie. Wir konnten erstmals nachweisen, dass die Blockade des B2-Rezeptors mit dem neu entwickelten Nicht-Peptid Antagonisten LF 16-0687 MS die Infarktbildung hemmt und die funktionelle neurologische Erholung nach temporärer fokaler zerebraler Ischämie bei Ratten verbessert, ohne Nebenwirkungen auf physiologische Kontrollparameter auszuüben.
Die dosisabhängige Wirkung von LF 16-0687 Ms konnte in unserem Modell der temporären fokalen zerebralen Ischämie bei der Ratte bestätigt werden.
Mit unseren Ergebnissen konnten wir quantitativ nachweisen, dass durch die B2-Rezeptor-Blockade mit LF 16-0687 Ms die postischämische Hirnschwellung nach fokaler zerebraler Ischämie bei Ratten gehemmt wird.
Die neuroprotektive Wirkung besteht auch bei Therapiebeginn nach Ischämie, was die weitere in vivo und in vitro Evaluierung des Antagonisten verdient.
Die Ergebnisse dieser Arbeit bilden die Grundlage für weitere Untersuchungen des Kallikrein-Kinin-Systems insbesondere der B1- und B2-Rezeptor-Interaktionen bei fokaler und globaler zerebraler Ischämie, bei Schädel-Hirn-Trauma und bei in vitro Untersuchungen
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
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