1,720,963 research outputs found
Manganese Cytotoxicity Assay on Hippocampal Neuronal Cell Culture
Full text linkCompared to an in vivo experiment, neuronal cell cultures are immediately accessibleto observation and manipulation. In this protocol, we describe a technique to evaluate thecytotoxicity of a metal, manganese (Mn2+), on hippocampal neuronal cell cultures. Interestingly, this protocol is easily adaptable to any type of primary culture (e.g., cortical neurons) and any type of toxic compound (e.g., chemical product).Fil: Daoust, Alexia. Inserm; Francia. Universite Joseph Fourier; FranciaFil: Saoudi, Yasmina. Inserm; Francia. Universite Joseph Fourier; FranciaFil: Brocard, Jacques. Inserm; Francia. Universite Joseph Fourier; FranciaFil: Collomb, Nora. Inserm; Francia. Universite Joseph Fourier; FranciaFil: Batandier, Cecile. Laboratoire de Bioénergétique Fondamentale et Appliquée; FranciaFil: Bisbal, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentina. Inserm; Francia. Universite Joseph Fourier; FranciaFil: Salome, Murielle. European Synchrotron Radiation Facility; FranciaFil: Andrieux, Annie. Inserm; Francia. Universite Joseph Fourier; FranciaFil: Bohic, Sylvain. Inserm; Francia. Universite Joseph Fourier; Francia. European Synchrotron Radiation Facility; FranciaFil: Barbier, Emmanuel. Inserm; Francia. Universite Joseph Fourier; Franci
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
Manganese MRI (MEMRI) : coupling chemical imaging by synchrotron micoprobe to optimize the functional imaging of neuronal transport.
No full textRésumé Le manganèse (Mn2+) est un élément essentiel du corps humain. Ses propriétés paramagnétiques permettent son utilisation comme agent de contraste pour l'IRM (Mn-MRI ou MEMRI). Analogue du calcium (Ca2+), il pénètre les neurones essentiellement par les canaux calciques. Il est ensuite transporté le long des microtubules jusqu'aux synapses où il est libéré, puis capturé par les autres neurones. Ainsi, il peut rendre compte du transport axonal antérograde et rétrograde. L'approche MEMRI peut ainsi apporter des informations uniques sur la connectivité fonctionnelle cérébrale. Toutefois, deux problèmes limitent l'emploi de ce puissant outil d'imagerie in vivo : (i) A doses élevées, le Mn2+ est toxique pour l'organisme et peut provoquer une atteinte grave du système nerveux central, appelé manganisme. Les niveaux et les mécanismes de toxicité sont mal connus. (ii) Le mode de transport du manganèse dans l'approche MEMRI est mal connu. Afin d'apporter des éléments de réponse à ces deux problèmes, nous avons entrepris une étude couplant IRM et microscopie synchrotron pour mieux comprendre le comportement du Mn2+ in vivo. Nous avons précisé les distributions cellulaire et sub-cellulaire du Mn et d'autres métaux pour un modèle de cellules de type neuronal (lignée de neuroblastome N2A), pour des cultures primaires de neurones hippocampiques, mais aussi au niveau de coupes d'hippocampe de rats. En parallèle, nous avons étudié les effets du Mn sur le métabolisme cérébral par une technique de RMN-HRMAS du proton. Pour compléter ce travail, nous avons mis en œuvre l'imagerie MEMRI chez les souris KO MAP6 présentant un déficit d'une protéine stabilisatrice des microtubules pour évaluer la connectivité fonctionnelle du tract thalamo-cortical. Mots clés Hippocampe, MAP6, manganèse, métabolisme, métal, neurone, MRI, rongeurs, synchrotron.Abstract Manganese (Mn2+) is an essential element for human body. The paramagnetic properties of Mn2+ permit it use as a contrast agent for MRI (Mn-MRI or MEMRI). Analogue of calcium (Ca2+), it enters neurons primarily by calcium channels. It is then transported along microtubules to the synapse where it is released and then captured by other neurons. Thus, it can account for the anterograde and retrograde axonal transport. The MEMRI approach can provide unique information about cerebral functional connectivity. Two problems limit the use of this powerful tool for in vivo imaging: (i) At high doses, Mn2+ is toxic to the body and can cause serious problem of the central nervous system, called manganism. The level and the mechanisms of toxicity are poorly understood. (ii) The mode of manganese transport in the MEMRI approach is unclear. To address these two issues, we undertook a study coupling MRI and synchrotron microscopy to study the Mn 2+ behavior in vivo. We characterized the cellular and subcellular distributions of Mn and other metals in "pseudo neurons" cell line N2A, primary cultures of hippocampal neurons, andin hippocampal slices from rats. In parallel, we studied the effects of Mn on brain metabolism by proton-HRMAS NMR . In parallel, weevaluated MEMRI in MAP6 KO mice which exhibit a deficit in microtubule stabilizing protein, to assess the functional connectivity of the thalamocortical tract. Key words hippocampus, MAP6, manganese, metabolism, metal, neuron, MRI, rodent, synchrotron
IRM du manganèse (MEMRI) : couplage à l'imagerie chimique par microsonde synchrotron pour optimiser l'imagerie fonctionnelle du transport neuronal
No full textAbstract Manganese (Mn2+) is an essential element for human body. The paramagnetic properties of Mn2+ permit it use as a contrast agent for MRI (Mn-MRI or MEMRI). Analogue of calcium (Ca2+), it enters neurons primarily by calcium channels. It is then transported along microtubules to the synapse where it is released and then captured by other neurons. Thus, it can account for the anterograde and retrograde axonal transport. The MEMRI approach can provide unique information about cerebral functional connectivity. Two problems limit the use of this powerful tool for in vivo imaging: (i) At high doses, Mn2+ is toxic to the body and can cause serious problem of the central nervous system, called manganism. The level and the mechanisms of toxicity are poorly understood. (ii) The mode of manganese transport in the MEMRI approach is unclear. To address these two issues, we undertook a study coupling MRI and synchrotron microscopy to study the Mn 2+ behavior in vivo. We characterized the cellular and subcellular distributions of Mn and other metals in "pseudo neurons" cell line N2A, primary cultures of hippocampal neurons, andin hippocampal slices from rats. In parallel, we studied the effects of Mn on brain metabolism by proton-HRMAS NMR . In parallel, weevaluated MEMRI in MAP6 KO mice which exhibit a deficit in microtubule stabilizing protein, to assess the functional connectivity of the thalamocortical tract. Key words hippocampus, MAP6, manganese, metabolism, metal, neuron, MRI, rodent, synchrotron.Résumé Le manganèse (Mn2+) est un élément essentiel du corps humain. Ses propriétés paramagnétiques permettent son utilisation comme agent de contraste pour l'IRM (Mn-MRI ou MEMRI). Analogue du calcium (Ca2+), il pénètre les neurones essentiellement par les canaux calciques. Il est ensuite transporté le long des microtubules jusqu'aux synapses où il est libéré, puis capturé par les autres neurones. Ainsi, il peut rendre compte du transport axonal antérograde et rétrograde. L'approche MEMRI peut ainsi apporter des informations uniques sur la connectivité fonctionnelle cérébrale. Toutefois, deux problèmes limitent l'emploi de ce puissant outil d'imagerie in vivo : (i) A doses élevées, le Mn2+ est toxique pour l'organisme et peut provoquer une atteinte grave du système nerveux central, appelé manganisme. Les niveaux et les mécanismes de toxicité sont mal connus. (ii) Le mode de transport du manganèse dans l'approche MEMRI est mal connu. Afin d'apporter des éléments de réponse à ces deux problèmes, nous avons entrepris une étude couplant IRM et microscopie synchrotron pour mieux comprendre le comportement du Mn2+ in vivo. Nous avons précisé les distributions cellulaire et sub-cellulaire du Mn et d'autres métaux pour un modèle de cellules de type neuronal (lignée de neuroblastome N2A), pour des cultures primaires de neurones hippocampiques, mais aussi au niveau de coupes d'hippocampe de rats. En parallèle, nous avons étudié les effets du Mn sur le métabolisme cérébral par une technique de RMN-HRMAS du proton. Pour compléter ce travail, nous avons mis en œuvre l'imagerie MEMRI chez les souris KO MAP6 présentant un déficit d'une protéine stabilisatrice des microtubules pour évaluer la connectivité fonctionnelle du tract thalamo-cortical. Mots clés Hippocampe, MAP6, manganèse, métabolisme, métal, neurone, MRI, rongeurs, synchrotron
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
- …
