1,721,509 research outputs found
Electro-Optical Imaging Microscopy of Dye Doped Lipid Bilayer
No full textTimes Cited: 0 Hajj, Bassam De Reguardati, Sophie Hugonin, Loic Osaki, Toshihisa Suzuki, Hiroaki Takeuchi, Shoji Le Pioufle, Bruno Chauvat, Dominique Zyss, Joseph Cleo/qels 2009 Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2009) Jun 02-04, 2009 Baltimore, MDInternational audienceWe report the first imaging of a dye-doped artificial bilayer using electro-optical microscopy. The applied voltage dependence confirms the origin of the effect. This result is an important step towards a contactless optical patch-clamp
Electro-Optical Imaging Microscopy of Dye Doped Lipid Bilayer
No full textTimes Cited: 0 Hajj, Bassam De Reguardati, Sophie Hugonin, Loic Osaki, Toshihisa Suzuki, Hiroaki Takeuchi, Shoji Le Pioufle, Bruno Chauvat, Dominique Zyss, Joseph Cleo/qels 2009 Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2009) Jun 02-04, 2009 Baltimore, MDInternational audienceWe report the first imaging of a dye-doped artificial bilayer using electro-optical microscopy. The applied voltage dependence confirms the origin of the effect. This result is an important step towards a contactless optical patch-clamp
Electro-Optical Imaging Microscopy of Dye Doped Lipid Bilayer
No full textTimes Cited: 0 Hajj, Bassam De Reguardati, Sophie Hugonin, Loic Osaki, Toshihisa Suzuki, Hiroaki Takeuchi, Shoji Le Pioufle, Bruno Chauvat, Dominique Zyss, Joseph Cleo/qels 2009 Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2009) Jun 02-04, 2009 Baltimore, MDInternational audienceWe report the first imaging of a dye-doped artificial bilayer using electro-optical microscopy. The applied voltage dependence confirms the origin of the effect. This result is an important step towards a contactless optical patch-clamp
Electro-Optical Imaging Microscopy of Dye Doped Lipid Bilayer
No full textTimes Cited: 0 Hajj, Bassam De Reguardati, Sophie Hugonin, Loic Osaki, Toshihisa Suzuki, Hiroaki Takeuchi, Shoji Le Pioufle, Bruno Chauvat, Dominique Zyss, Joseph Cleo/qels 2009 Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2009) Jun 02-04, 2009 Baltimore, MDInternational audienceWe report the first imaging of a dye-doped artificial bilayer using electro-optical microscopy. The applied voltage dependence confirms the origin of the effect. This result is an important step towards a contactless optical patch-clamp
Study of the application of pulsed electric fields (PEF) on microalgae for the extraction of neutral lipids.
No full textLes microalgues, de par leur diversité, peuvent offrir une multiplicité de molécules bio-sourcées pour des applications variées (alimentation, énergie, santé etc…). Cependant, la production de biodiesel à partir de microalgues, désignée comme la 3e génération de biocarburant, nécessite encore une optimisation lors de l’étape de culture de la biomasse ou lors de l’extraction de l’huile pour que le procédé soit énergétiquement viable. Parmi les voies d’amélioration, l’application de champs électriques pulsés (PEF) en prétraitement à la biomasse pourrait améliorer la rentabilité énergétique du procédé d’extraction de lipides. Ce procédé appliqué aux microalgues est étudié dans le contexte d’une collaboration entre le laboratoire SATIE de l’ENS Cachan Paris Saclay et le laboratoire LGPM de Paris Saclay.Un microsystème d’électroporation a été conçu afin d’étudier in situ l’impact des champs électriques pulsés sur les cellules de microalgue, Chlamydomonas reinhardtii chargées en lipides. Parmi les principaux résultats du projet, l’étude énergétique du procédé a montré que les impulsions de très courte durée (5 µs) sont les moins énergivores. Associées à un champ électrique de 4.5 kV/cm, ces impulsions entrainent une perméabilisation réversible (80 % de cellules atteintes) de quelques secondes tandis qu’un champ de 7 kV/cm entraine un effet irréversible. Après ce prétraitement, les algues sont ensuite mélangées à de l’hexane afin d’évaluer si les lipides sont extraits plus facilement de la cellule.Microalgae offer a multiplicity of applications for the production of bio-sourced compounds such as proteins, pigments, sugars and oils. However, the energy spent for algae culture and lipid extraction hinder the energetic viability of the process for the production of biofuel derived from algae oils. Among possible improvements, pulsed electric fields (PEF) may be used as a pre-treatment to extract valuable compounds from microalgae and making the process less energy demanding.This project started with a collaboration between the team of bio-micro-systems Biomis, laboratory SATIE, with the team of bio-process engineering laboratory LGPM to study in situ the effects of PEF on microalgae.First, a energetic study is performed in a micro-system specially built for this project to characterize in situ, the effect of various treatment parameters (pulse duration / electric field) on Chlamydomonas reinhardtii cells with high lipid content.Among the outputs of this study, an energetic optimization of PEF conditions shows that a high level of permeability and low energy consumption are obtained when using short pulses of 5 µs. Associated with an electric field of 4.5 kV/cm, the pores are reversible (80% of the cells) during few seconds, and with a field of 7 kV/cm or higher, the permeabilization is irreversible. Afterwards, this PEFpre-treatment is associated with solvent mixing (hexane) to evaluate if lipid extraction is improved
New methods for continuous microorganism separation from biological samples within a microsystem
No full textDans le domaine du diagnostic in vitro, l'étape d'extraction de micro-organismes à partir d'un échantillon complexe est une étape clé pour permettre l'identification du pathogène responsable d'une infection. Pour les septicémies, cette étape d'extraction est généralement précédée d'une étape de culture, ce qui conduit à une obtention des résultats au bout de plusieurs jours. Un résultat plus rapide (typiquement inférieur à 24h) permettrait d'augmenter le taux de survie des patients, et aurait ainsi une forte valeur ajoutée pour le corps médical. Le but de ces travaux est donc de développer une nouvelle méthode d'extraction et de concentration de pathogènes directement à partir d'un échantillon sanguin, sans étape de culture. Une stratégie en deux modules microfluidiques associés en série est proposée : elle repose sur la modification de la conductivité et de l'osmolarité de l'échantillon dans un premier module, puis sur la capture des micro-organismes par diélectrophorèse dans un second module. L'étude du premier module a permis de déterminer l'impact de la conductivité et de l'osmolarité du milieu sur les propriétés diélectriques des cellules. Deux voies ont ainsi été abordées, afin de diriger les cellules du sang et les micro-organismes vers un milieu de conductivité et d'osmolarité contrôlées : la dilution, et l'utilisation de forces acoustiques. L'étude du deuxième module a ensuite permis de démontrer la possibilité de capturer et concentrer des micro-organismes à partir d'un échantillon hypotonique et faiblement conducteur dans un écoulement microfluidique par diélectrophorèse. L'architecture d'un microsystème dédié a été définie grâce à un modèle numérique, puis validé expérimentalement avec des échantillons sanguins et différents micro-organismes (E. coli, S. epidermidis et C. albicans). La capture générique des micro-organismes est démontrée, et un taux de capture de 97% a été obtenu pour la séparation de \EC, avec une vitesse moyenne de l'échantillon dans le microsystème de 100 à 200 µm.s-1. Enfin, des perspectives d'amélioration sont présentées pour permettre d'effectuer cette étape de séparation sur un gros volume d'échantillon (1 à 10mL) en quelques heures, afin de répondre aux exigences imposées par l'urgence des tests de diagnostic des septicémies.Extraction of pathogens from a biological sample is a key step for efficient diagnostic tests of infectious diseases. For bloodstream infections, current diagnostic methods are usually based on bacterial growth and take several days to provide valuable information. An accelerated result would have a high medical value to adjust therapeutic strategies. The aim of this study is to design a new approach for separation and concentration of microorganisms directly from a blood sample, to avoid time-consuming growth stages. We report a method based on two different microsystems connected in series: it combines modification of conductivity and osmolarity of the sample with generic capture of microorganisms by dielectrophoresis. First we explore the impact of conductivity and osmolarity on the dielectric properties of blood cells and microorganisms. Dilution and acoustic forces are both analyzed to transfer blood cells and microorganisms to the optimized buffer. Then we demonstrate the feasibility of achieving the dielectrophoretic separation of microorganisms from blood cells in a low conductivity and low osmolarity medium inside a fluidic device. The structure of the device is optimized with numerical simulations and experiments performed on blood samples and various microorganisms (E. coli, S. epidermidis and C. albicans).The generic capture of microorganisms is validated, and we achieved a separation of 97% efficiency with E. coli, with an optimal inlet velocity around 100-200 µm.s-1. Finally, we propose an improved microsystem to perform the sample preparation step on a larger volume (1-10mL) in a few hours, in order to fit the medical need
Comparaison de strategies pour la commande numerique de servomoteurs synchrones - algorithmes lineaires et non lineaires - robustesse - implantation
No full textSIGLEINIST T 75410 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
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
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