1,720,964 research outputs found
Implication des Protéine kinases C et de p38MAPK dans la modulation de marqueurs de différenciation épidermique dans des kératinocytes déplétés en cholestérol
Get PDFStudy of cell responses after lipid raft disruption by cholesterol depletion in epidermal keratinocytes
No full textThe skin assumes a fascinating protection role by producing a barrier between the environment and the organism. This barrier, formed by the differentiation of epidermal keratinocytes, is vital for the organism as the skin is constantly exposed to external aggressions.
In this study, we investigated the relevance of membrane cholesterol and lipid rafts in normal epidermal keratinocytes by extracting cholesterol with methyl-beta-cyclodextrin. Actually, the scientific interest in plasma membranes has strongly increased since the discovery that cholesterol-enriched membrane microdomains domains, lipid rafts, are directly involved in cell signaling. Our study identifies the heparin-binding EGF-like growth factor (HB-EGF) as a major actor after lipid raft disruption, HB-EGF is also shown to be expressed in wound-healing skin after burn injury. Parallelisms in the keratinocyte’s response to lipid raft disruption or to oxidative stress incited the investigation potential oxidative stress-mediated effects in cholesterol-depleted cells, but our results clearly demonstrate that lipid raft disruption does not initiate oxidative stress mechanisms. An unbiased microarray approach was then chosen to determine major actors, functions and pathways. HB-EGF, interleukin-8, urokinase-like plasminogen activator and its receptor are identified among the major transcriptional targets in lipid raft-disrupted keratinocytes. Moreover, bioinformatics analysis of differentially regulated genes permitted to establish a potential link with atopic dermatitis, an inflammatory skin disease. This hypothesis was investigated, and confirmed, in skin biopsies of atopic dermatitis patients.
Thus, our study contributes to a better understanding of lipid raft biology and suggests that the functioning of keratinocyte lipid rafts could be compromised in atopic dermatitis.La peau assure un rôle de protection important en élaborant une barrière entre l’organisme et l’environnement. Cette barrière est essentiellement formée par la différentiation progressive de kératinocytes épidermiques. La barrière épidermique joue un rôle capital pour l’organisme puisque la peau est constamment exposée aux agressions externes.
Dans cette étude, nous avons analysé l’importance du cholestérol membranaire et des lipid rafts dans des kératinocytes épidermiques normaux en déplétant le cholestérol à l’aide de la molécule methyl-beta-cyclodextrin. Depuis la découverte de l’implication directe de lipid rafts dans la signalisation cellulaire, l’intérêt scientitfique pour ces microdomaines membranaires enrichis en cholestérol a fortement augmenté.
Notre étude identifie le facteur de croissance heparin-binding EGF-like growth factor (HB-EGF) comme un des acteurs majeurs suite à une perturbation des lipid rafts via extraction de cholestérol. Nous montrons également que HB-EGF est exprimé dans la peau en cicatrisation après blessure par brûlure cutanée. Les parallélismes dans la réponse des kératinocytes face à la perturbation des lipid rafts ou face au stress oxydatif nous ont incités à investiguer si des éventuels méchanismes de stress oxydatif sont impliqués dans les effets induits par une déplétion en cholestérol. Cependant, nos résultats démontrent clairement que la perturbation des lipid rafts n’induit pas de mécanismes de stress oxydatif. Par la suite, une approche transcriptomique sans a priori a été choisie pour déterminer les acteurs majeurs, fonctions et voies de signalisation. HB-EGF, interleukin-8, urokinase-like plasminogen activator et son récepteur sont identifiés parmi les cibles transcriptionnelles majeures dans les kératinocytes déplétés en cholestérol. De plus, des analyses bioinformatiques de gènes différentiellement régulés ont permis d’établir un lien potentiel avec la dermatite atopique, une maladie inflammatoire de la peau. Cette hypothèse a été investiguée, et confirmée, dans des biopsies de peau de patients atteints de dermatite atopique. Nos données contribuent donc à une meilleure compréhension de la biologie cutanée des lipid rafts et suggèrent que la fonctionnalité des lipid rafts de kératinocytes situés dans les lésions de dermatite atopique pourrait être compromise.(DOCMED02) -- FUNDP, 201
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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