1,720,970 research outputs found
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
The Endogenous Retroviral Envelop Protein HEMO : A Cancer Biomarker and Potential Therapeutic Target
No full textLe génome humain contient environ 8% de séquences rétrovirales endogènes ou « HERVs » (Human Endogenous Retrovirus), vestiges d’anciennes intégrations de rétrovirus exogènes infectieux, ayant eu lieu au cours de l’évolution des vertébrés. La plupart de ces séquences sont devenues non fonctionnelles par accumula tion de mutations, délétions ou réarrangements chromosomiques. Quelques séquences rétrovi rales ont cependant conservé leur capacité codante comme le gène HEMO (Human Endogenous MER34 ORF) codant une protéine d’enveloppe membranaire récemment identifiée au laboratoire et qui a la particularité d’être libérée dans le milieu extracellulaire sous une forme soluble. HEMO est exprimé principalement dans le placenta ainsi que dans les cellules souches pluripotentes. Des données préliminaires ont suggéré que ce gène pouvait également être activé en contexte tumoral. L’objectif de cette étude a donc été de caractériser l’expression de HEMO dans les tumeurs. En combinant des approches de bioinformatique et de biologie moléculaire avec l’analyse d’échantillons de patients, nous avons ainsi démontré que HEMO était activé dans de nombreuses tumeurs solides primaires et métastatiques (tumeurs gynécologiques, pulmonaires, digestives, mammaires, urothéliales et ORL) et que son expression était modulée par la voie de signalisation Wnt/β-caténine. En parallèle, nous avons cherché à développer un test sensible permettant de détecter la protéine HEMO sécrétée dans des fluides biologiques (sérum, urine etc...) chez des patients atteints de cancer. Pour conclure, ces travaux soulignent l’intérêt de la protéine HEMO en tant que cible pour le développement de thérapies anti-tumorales ou comme biomarqueur protéique circulant.Human endogenous retroviral se quences (HERVs) represent approximatively 8% of our genome and are remnants of ancestral infections by exogenous retrovirus that happened during evolution of vertebrates. Most of these sequences have become defective due to accumulation of mutations, deletions or chromosomal rearrangements. Nevertheless, some retroviral sequences retained their coding capacity, such as the HEMO gene (Human Endogenous MER34 ORF) encoding a membrane envelope protein, recently discovered in our group. HEMO has the particularity to be actively cleaved from the cell membrane and secreted as a shed protein. HEMO is mainly expressed in placenta and pluripotent stem cells and preliminary data suggested that this gene could also be activated in tumor condition. The aim of this study was to characterize HEMO expression in tumors. By combining different ap proaches such as bioinformatics and molecular biology with the analysis of patient samples, we thus demonstrated that HEMO was activated in numerous primary and metastatic solid tumors (gynecological, pulmonary, digestive, mammary, urothelial and oral tumors) and that its expression was modulated by Wnt/β-catenin signaling pathway. Furthermore, we sought to develop a sensitive test in order to detect HEMO protein in bio-logic fluids (serum, urine etc..) from patients with cancer. In conclusion, this work underlines potential interest of HEMO as a target for development of anti-tumor therapies or as a circulating protein biomarker
Evolutionary history of the oldest endogenous retroviral envelope gene HEMO still coding in humans, expressed in the placenta and tumors : recent acquisition of an interaction with a transmembrane protease in primates
No full textLe génome humain contient environ 8% de séquences rétrovirales endogènes, vestiges d'infections des cellules de la lignée germinale par des rétrovirus infectieux exogènes chez des mammifères ancestraux. La protéine d'enveloppe rétrovirale endogène HEMO (Human Endogenous MER34 ORF), récemment identifiée au laboratoire, provient d'une intégration rétrovirale survenue il y a 100 millions d'années et a été sélectionnée pour une fonction physiologique. Le gène HEMO est exprimé dans les cellules souches, le placenta ainsi que dans un grand nombre de tumeurs. Contrairement aux enveloppes rétrovirales classiques, la protéine HEMO a perdu ses propriétés de fusion, conservées par exemple dans le cas des syncytines. Elle a acquis la propriété remarquable d'être clivée spécifiquement à la membrane de la cellule, puis libérée sous une forme soluble, dite « SHED », dans le milieu extracellulaire. En conséquence, cette forme est présente dans le sang périphérique des femmes enceintes, avec des concentrations qui augmentent tout au long de la grossesse. La protéine HEMO pourrait jouer un rôle dans la physiologie placentaire et/ou exercer une action à distance sur des organes cibles de la femme enceinte. Pour déterminer le rôle de la protéine HEMO dans l'organisme, nous avons cherché ses partenaires membranaires ou récepteurs cellulaires et pour cela, nous avons criblé une banque d'expression en utilisant une méthode innovante de fusion cellule-cellule, qui exploite les propriétés fusogéniques des glycoprotéines H et F du virus de la rougeole. Nous avons alors identifié une interaction spécifique avec une protéase transmembranaire et grâce à des approches de reconstruction de séquences ancestrales, nous avons pu suggérer que cette interaction a été acquise suite à deux mutations, apparues entre 45 et 30 millions d'années chez des ancêtres primates, et qui ont provoquée des modifications structurelles de la protéine HEMO, notamment la perte de son site de clivage à la furine. Cette récente acquisition dans son histoire évolutive pourrait être à l'origine d'une nouvelle fonction. Aussi, nous avons développé un modèle transgénique murin en introduisant le gène HEMO, perdu chez la souris, afin d'identifier l'apparition d'éventuels phénotypes. Enfin, la protéine HEMO constituant une cible thérapeutique potentielle pour traiter certains cancers, nous avons entrepris de développer un anticorps couplé à un agent cytotoxique (Antibody-Drug Conjugate, ADC), pour cibler spécifiquement les tumeurs HEMO positives.The human genome contains approximately 8% endogenous retroviral sequences, which are remnants of infections of germline cells by exogenous infectious retroviruses in ancestral mammals. The endogenous retroviral envelope protein HEMO (Human Endogenous MER34 ORF), recently identified in the laboratory, originates from a retroviral integration that occurred 100 million years ago and has been selected for a physiological function. The HEMO gene is expressed in stem cells, the placenta, and many tumors. Unlike classical retroviral envelopes, the HEMO protein has lost its fusion properties, which are retained, for example, in the case of syncytins. It has acquired the remarkable property to be specifically cleaved at the cell membrane and then released as a “SHED” soluble form, into the extracellular environment. Consequently, the SHED HEMO protein is present in the peripheral blood of pregnant women, with concentrations increasing throughout pregnancy. The HEMO protein could play a role in placental physiology and/or exert effects on distant target organs in pregnant women. To determine the role of the HEMO protein in the organism, we looked for its membrane partners or cellular receptors and screened an expression library using an innovative cell-cell fusion method that leverages the fusogenic properties of the H and F envelope glycoproteins from the measles virus. We then identified a specific interaction with a transmembrane protease, and through ancestral sequence reconstruction approaches, we could suggest that this interaction was acquired following two mutations, which appeared between 45 and 30 million years ago in primate ancestors. These mutations induced structural changes in the HEMO protein, notably by the loss of its furin cleavage site. This recent acquisition in its evolutionary history could be at the origine of a new function. We have therefore developed a murine transgenic model by introducing the HEMO gene, which is absent in mice, in order to identify the appearance of any phenotypes. Finally, since the HEMO protein is a potential therapeutic target for certain cancers, we are developing an antibody-drug conjugate to specifically target HEMO-positive tumors
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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