170,565 research outputs found
Label free dynamic imaging: application to phage infected bacteria
No full textInternational audienceOur aim is to develop live imaging tools and methods that are not destructive (fixation) and do not need molecular manipulations.We first described a set up, which allows detection and analysis of phages (diameter from 35nm to 100nm and more) as well as other nanoparticles by following their Brownian motion (diffusion). In addition we showed that we could differentiate viruses from membrane vesicles based on their different refractive index (a). We challenged our set up to compare it to labelling coupled flow cytometry of viruses and vesicles from different lakes from Massif Central.We also recently developed a new tomographic approach (Optical transmission tomography) that has led to explore new fields: 1) We were interested to quantify metabolic activity within algae in different environmental conditions (b). We were able to detect and quantify movements within a cell under different environmental stresses.2) We identified dynamic structures in E. coli during infection by T5 phage (a generous gift of Pascale Boulanger)All the results will be presented and discussed for more applications.(a) Boccara, M., Fedala Y., Vénien-Bryan C., Bailly-Bechet M., Bowler C., Boccara A.C., Full field interferometry for counting and differentiating aquatic biotic nanoparticles: from laboratory to Tara Oceans. Biomed Opt Express Vol. 7, 3736-3746, (2016).(b) Houda Bey, Florent Charton, Helena Cruz de Carvalho, Shun Liu, Richard G. Dorrell, Chris Bowler, Claude Boccara & Martine Boccara (2022): Dynamic Cell Imaging: application to the diatom Phacodactylum tricornutum under environmental stresses, European Journal of Phycol- ogy, DOI: 10.1080/09670262.2022.208173
Label free dynamic imaging: application to phage infected bacteria
No full textInternational audienceOur aim is to develop live imaging tools and methods that are not destructive (fixation) and do not need molecular manipulations.We first described a set up, which allows detection and analysis of phages (diameter from 35nm to 100nm and more) as well as other nanoparticles by following their Brownian motion (diffusion). In addition we showed that we could differentiate viruses from membrane vesicles based on their different refractive index (a). We challenged our set up to compare it to labelling coupled flow cytometry of viruses and vesicles from different lakes from Massif Central.We also recently developed a new tomographic approach (Optical transmission tomography) that has led to explore new fields: 1) We were interested to quantify metabolic activity within algae in different environmental conditions (b). We were able to detect and quantify movements within a cell under different environmental stresses.2) We identified dynamic structures in E. coli during infection by T5 phage (a generous gift of Pascale Boulanger)All the results will be presented and discussed for more applications.(a) Boccara, M., Fedala Y., Vénien-Bryan C., Bailly-Bechet M., Bowler C., Boccara A.C., Full field interferometry for counting and differentiating aquatic biotic nanoparticles: from laboratory to Tara Oceans. Biomed Opt Express Vol. 7, 3736-3746, (2016).(b) Houda Bey, Florent Charton, Helena Cruz de Carvalho, Shun Liu, Richard G. Dorrell, Chris Bowler, Claude Boccara & Martine Boccara (2022): Dynamic Cell Imaging: application to the diatom Phacodactylum tricornutum under environmental stresses, European Journal of Phycol- ogy, DOI: 10.1080/09670262.2022.208173
Sharing the driving-course of a same trainee between different trainers, what are the consequences?
No full textInternational audienceVidal-Gomel, C., Boccara, V., Rogalski, J. & Delhomme, P. (2012). Work, 41 (2), 205-215
THEORETICAL AND EXPERIMENTAL ADVANTAGES OF A COMPACT MIRAGE SPECTROSCOPY SETUP FOR TRACE GAS DETECTION
No full textB. Zimering, A. C. Boccara, Rev. Sci. Inst. (in press)Author Institution: CNRS UPR A0005, Laboratorie d'Optique PhysiqueWe present the advantages of a compact setup for real time in situ trace gas detection based on photothermal deflection spectroscopy optimized for practical . The use of high quality Ge windows permits a true parallel geometry, resulting in a design resistant to ambient air motion while preserving the advantages the technique presents with respect to standard absorption spectroscopy, such as good sensitivity, local sample probing and open air measurement capability, We estimate the detection limit of in an atmosphere to be 100 ppt, and have measured real time in situ emissions from a variety of solid and semisolid samples to evaluate environmental, industrial, and argicultural applications
La Nano-Biophotonique au USA
No full textRapport de la mission scientifique de l'Ambassade de France aux Etats-UnisH. Rigneault, A. Alexendrou, S. Brasselet, L. Cognet, C. Royer, D. Marguet et C. Boccara
La Nano-Biophotonique au USA
No full textRapport de la mission scientifique de l'Ambassade de France aux Etats-UnisH. Rigneault, A. Alexendrou, S. Brasselet, L. Cognet, C. Royer, D. Marguet et C. Boccara
La Nano-Biophotonique au USA
No full textRapport de la mission scientifique de l'Ambassade de France aux Etats-UnisH. Rigneault, A. Alexendrou, S. Brasselet, L. Cognet, C. Royer, D. Marguet et C. Boccara
La Nano-Biophotonique au USA
No full textRapport de la mission scientifique de l'Ambassade de France aux Etats-UnisH. Rigneault, A. Alexendrou, S. Brasselet, L. Cognet, C. Royer, D. Marguet et C. Boccara
Sharing the driving-course of a same trainee between different trainers, what are the consequences?
No full textInternational audienceVidal-Gomel, C., Boccara, V., Rogalski, J. & Delhomme, P. (2012). Work, 41 (2), 205-215
Angular and Linear Speed Cells in the Parahippocampal Circuits
No full textAn essential role of the hippocampal region is to integrate information to compute and update representations. How this transpires is highly debated. Many theories hinge on the integration of self-motion signals and the existence of continuous attractor networks (CAN). CAN models hypothesise that neurons coding for navigational correlates – such as position and direction – receive inputs from cells conjunctively coding for position, direction and self-motion. As yet, such conjunctive coding had not been found in the hippocampal region. Here, we report neurons coding for angular and linear velocity, distributed across the medial entorhinal cortex, the presubiculum and the parasubiculum. These self-motion neurons often conjunctively encoded position and/or direction, yet lacked a structured organisation, calling for the revision of current CAN models. These results offer insights as to how linear/angular speed – derivative in time of position/direction – may allow the updating of spatial representations, possibly uncovering a generalised algorithm to update any representation
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