1,720,960 research outputs found
Analyse multi-échelle et approche bioinspirée de la reconstruction de la jonction myotendineuse
No full textThe complexity of the musculoskeletal system lies in the individuality of each tissues function. It has been demonstrated that a deficiency in one of these tissues can have negative effects on the whole system. Therefore, the need to build an in vitro relevant model of the musculoskeletal system, allowing the study of each of these tissues in their surrounding environment is a key challenge today. This thesis work is on a 2.5D tissue engineered skeletal muscle and a co-culture platform to study the establishment of the myotendinous junction. The work focuses on the development of a material for muscle tissue regeneration. The idea was to use a combination of an PCL electrospun sheet reinforced by PEG hydrogel micropatterning to create an environment that supports myoblast proliferation and fusion. The potential effect of cyclic stretching or electrical stimulation on the cells construct was investigated. Both stimulations enhance significantly cell differentiation and maturation. To investigate the development of the myotendinous junctions, a co-culture of C2C12 and BMSCs was set up. The results have led to 2 scientific articles and 1 review.La complexité du système musculo-squelettique réside dans les fonctions de chaque tissu. Il a été démontré que lorsque l’un de ces tissus est déficient cela peut avoir des effets néfastes sur l’ensemble du système. Par conséquent, il est nécessaire de mettre au point un modèle in vitro du système musculo-squelettique, pour étudier chacun de ces tissus ainsi que leur environnement. Ce travail de thèse se porte sur le développement d’un muscle squelettique par ingénierie tissulaire et de la mise au point d’un modèle de co-culture pour étudier la formation de la jonction myotendineuse. Le travail s’est focalisé sur le développement d’un matériau pour la régénération musculaire. Le but est de combiner le feuillet de PCL obtenu par électrofilage avec une topographie de surface que peut apporter l’hydrogel en PEG. Ceci pour créer un environnement qui favorise la prolifération et la fusion des myoblastes (C2C12). Par la suite, nous avons voulu déterminer si l’ajout de stimulation électrique ou mécanique sur nos biomatériaux avait un effet synergique sur les cellules. Les deux stimulations améliorent significativement la différenciation et la maturation des cellules. Pour étudier le développement de la jonction myotendineuse, une co-culture de C2C12 et de BMSC a été mis en place. Les résultats de cette thèse ont donné lieu à 2 articles scientifiques et 1 revue
Analyse multi-échelle et approche bioinspirée de la reconstruction de la jonction myotendineuse
No full textThe complexity of the musculoskeletal system lies in the individuality of each tissues function. It has been demonstrated that a deficiency in one of these tissues can have negative effects on the whole system. Therefore, the need to build an in vitro relevant model of the musculoskeletal system, allowing the study of each of these tissues in their surrounding environment is a key challenge today. This thesis work is on a 2.5D tissue engineered skeletal muscle and a co-culture platform to study the establishment of the myotendinous junction. The work focuses on the development of a material for muscle tissue regeneration. The idea was to use a combination of an PCL electrospun sheet reinforced by PEG hydrogel micropatterning to create an environment that supports myoblast proliferation and fusion. The potential effect of cyclic stretching or electrical stimulation on the cells construct was investigated. Both stimulations enhance significantly cell differentiation and maturation. To investigate the development of the myotendinous junctions, a co-culture of C2C12 and BMSCs was set up. The results have led to 2 scientific articles and 1 review.La complexité du système musculo-squelettique réside dans les fonctions de chaque tissu. Il a été démontré que lorsque l’un de ces tissus est déficient cela peut avoir des effets néfastes sur l’ensemble du système. Par conséquent, il est nécessaire de mettre au point un modèle in vitro du système musculo-squelettique, pour étudier chacun de ces tissus ainsi que leur environnement. Ce travail de thèse se porte sur le développement d’un muscle squelettique par ingénierie tissulaire et de la mise au point d’un modèle de co-culture pour étudier la formation de la jonction myotendineuse. Le travail s’est focalisé sur le développement d’un matériau pour la régénération musculaire. Le but est de combiner le feuillet de PCL obtenu par électrofilage avec une topographie de surface que peut apporter l’hydrogel en PEG. Ceci pour créer un environnement qui favorise la prolifération et la fusion des myoblastes (C2C12). Par la suite, nous avons voulu déterminer si l’ajout de stimulation électrique ou mécanique sur nos biomatériaux avait un effet synergique sur les cellules. Les deux stimulations améliorent significativement la différenciation et la maturation des cellules. Pour étudier le développement de la jonction myotendineuse, une co-culture de C2C12 et de BMSC a été mis en place. Les résultats de cette thèse ont donné lieu à 2 articles scientifiques et 1 revue
Super-Resolution-Chip: an in-vitro platform that enables super-resolution microscopy of co-cultures and 3D systems
Get PDFThe development of organs-on-a-chip platforms has revolutionized in-vitro cellular culture by allowing cells to be grown in an environment that better mimics human physiology. However, there is still a challenge in integrating those platforms with advanced imaging technology. This is extremely important when we want to study molecular changes and subcellular processes on the level of a single molecule using super-resolution microscopy (SRM), which has a resolution beyond the diffraction limit of light. Currently, existing platforms that include SRM have certain limitations, either as they only support 2D monocultures, without flow or as they demand a lot of production and handling. In this study, we developed a Super-Res-Chip platform, consisting of a 3D-printed chip and a porous membrane, that could be used to co-culture cells in close proximity either in 2D or in 3D while allowing SRM on both sides of the membrane. To demonstrate the functionality of the device, we co-cultured in endothelial and epithelial cells and used direct stochastic optical reconstruction microscopy (dSTORM) to investigate how glioblastoma cells affect the expression of the gap-junction protein Connexin43 in endothelial cells grown in 2D and in 3D. Cluster analysis of Connexin43 distribution revealed no difference in the number of clusters, their size, or radii, but did identify differences in their density. Furthermore, the spatial resolution was high also when the cells were imaged through the membrane (20-30 nm for x-y) and 10-20 nm when imaged directly both for 2D and 3D conditions. Overall, this chip allows to characterize of complex cellular processes on a molecular scale in an easy manner and improved the capacity for imaging in a single molecule resolution complex cellular organization
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
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