1,720,999 research outputs found
Mesure par microscopie confocale du métabolisme mitochondrial et du niveau énergétique cellulaire au cours d’épisodes de carences en substrats et/ou en oxygène
Full text linkMitochondria form an information hub at the center of the cellular metabolism because of its physiological role consisting in the porduction of ATP from the degradation of porducts stemming from our food through the OXPHOS process. However, changes in the functionnig of the mitochondria can be responsible for numerous diseases. Among the different foms of metabolic stress leading to mitchondrial dysfunctions, ischemia-reperfusion can be found in numerous pathological situations. This work aims at developing a methodological approach based on confocal microscopy and image analysis to dissect –at cell level- the consequences of metabolic stress induced by episodes of deprivation in substrata associated or not with hypoxia or anoxia. Having developed the program of image analysis based on the « tophat » method, two approaches were designed to vizualize and quantify the mitochondrial function. The first one, combining TMRM labelling with NADH fluorescence made it possible to highlight some differences in the response to the stress caused by ischemia-reperfusion at the level of the respiratory chain or concerning the PTP opening in the four cellular types that were tested : HMEC-1, INS1, RT112 or pirmary heaptocyes. The second approach consisted in testing the use of biosensors designed to follow the variations of ATP concentration (ATeam) or the activation of AMPK (AMPKAR). The experimental conditions established in this work did not allow us to validate their use.La mitochondrie est un carrefour d’informations au centre du fonctionnement cellulaire puisque son rôle physiologique consiste à récupérer l’énergie fournie par la dégradation des produits issus de notre alimentation pour produire de l’ATP, par le processus d’oxydation phosphorylante. Cependant, des altérations du fonctionnement de la mitochondrie peuvent être responsables de nombreuses pathologies. Parmi les stress métaboliques pouvant entraîner un dysfonctionnement mitochondrial, l’ischémie-reperfusion est un phénomène présent également dans de nombreuses situations pathologiques. L’objectif de ce travail consiste à développer une approche méthodologique basée sur la microscopie confocale et l’analyse d’images afin de décortiquer les conséquences cellulaires des stress métaboliques induits lors d’épisodes de privation de substrats associée ou non à une privation partielle ou totale d’oxygène. Après avoir mis au point le programme d’analyse d’images basée sur la méthode du « tophat », deux approches ont été développées pour visualiser et quantifier la fonction mitochondriale. La première, qui combine le marquage du TMRM et l’autofluorescence du NADH, a permis de mettre en évidence des différences de réponses au stress d’ischémie-reperfusion au niveau de la chaîne respiratoire ou de l’ouverture du PTP pour les quatre types cellulaires testés : HMEC-1, INS1, RT112 ou hépatocytes primaires. La seconde approche a consisté à tester l’utilisation de biosenseurs permettant de suivre les variations de concentration d’ATP (Ateam) ou d’activation de l’AMPK (AMPKAR). Les conditions expérimentales réalisées dans ce travail n’ont pas permis de valider leur utilisation
Mesure par microscopie confocale du métabolisme mitochondrial et du niveau énergétique cellulaire au cours d’épisodes de carences en substrats et/ou en oxygène
No full textMitochondria form an information hub at the center of the cellular metabolism because of its physiological role consisting in the porduction of ATP from the degradation of porducts stemming from our food through the OXPHOS process. However, changes in the functionnig of the mitochondria can be responsible for numerous diseases. Among the different foms of metabolic stress leading to mitchondrial dysfunctions, ischemia-reperfusion can be found in numerous pathological situations. This work aims at developing a methodological approach based on confocal microscopy and image analysis to dissect –at cell level- the consequences of metabolic stress induced by episodes of deprivation in substrata associated or not with hypoxia or anoxia. Having developed the program of image analysis based on the « tophat » method, two approaches were designed to vizualize and quantify the mitochondrial function. The first one, combining TMRM labelling with NADH fluorescence made it possible to highlight some differences in the response to the stress caused by ischemia-reperfusion at the level of the respiratory chain or concerning the PTP opening in the four cellular types that were tested : HMEC-1, INS1, RT112 or pirmary heaptocyes. The second approach consisted in testing the use of biosensors designed to follow the variations of ATP concentration (ATeam) or the activation of AMPK (AMPKAR). The experimental conditions established in this work did not allow us to validate their use.La mitochondrie est un carrefour d’informations au centre du fonctionnement cellulaire puisque son rôle physiologique consiste à récupérer l’énergie fournie par la dégradation des produits issus de notre alimentation pour produire de l’ATP, par le processus d’oxydation phosphorylante. Cependant, des altérations du fonctionnement de la mitochondrie peuvent être responsables de nombreuses pathologies. Parmi les stress métaboliques pouvant entraîner un dysfonctionnement mitochondrial, l’ischémie-reperfusion est un phénomène présent également dans de nombreuses situations pathologiques. L’objectif de ce travail consiste à développer une approche méthodologique basée sur la microscopie confocale et l’analyse d’images afin de décortiquer les conséquences cellulaires des stress métaboliques induits lors d’épisodes de privation de substrats associée ou non à une privation partielle ou totale d’oxygène. Après avoir mis au point le programme d’analyse d’images basée sur la méthode du « tophat », deux approches ont été développées pour visualiser et quantifier la fonction mitochondriale. La première, qui combine le marquage du TMRM et l’autofluorescence du NADH, a permis de mettre en évidence des différences de réponses au stress d’ischémie-reperfusion au niveau de la chaîne respiratoire ou de l’ouverture du PTP pour les quatre types cellulaires testés : HMEC-1, INS1, RT112 ou hépatocytes primaires. La seconde approche a consisté à tester l’utilisation de biosenseurs permettant de suivre les variations de concentration d’ATP (Ateam) ou d’activation de l’AMPK (AMPKAR). Les conditions expérimentales réalisées dans ce travail n’ont pas permis de valider leur utilisation
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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