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189 results on '"COGNET, L."'

2. Highly Polarized Light Emission from 6T@BNNT Nanohybrids

Author

Badon, A., Allard, C., Fossard, F., Loiseau, A., Cognet, L., Flahaut, E., Izard, N., Martel, R., and Gaufrès, E.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Optics
Abstract

The polarized fluorescence emission of organic fluorophores has been extensively studied in photonics and is increasingly exploited in single molecule scale bio-imaging. Expanding the polarization properties of compact molecular assemblies is, however, extremely challenging due to depolarization and quenching effects associated with the self-aggregation of molecules into the sub-nanometer scale. Here we demonstrate that Boron Nitride Nanotubes (BNNTs) can act as a 1D host-template for the alignment of encapsulated a-sexithiophene (6T) inside BNNTs, leading to an optically active 6T@BNNT nanohybrid. We show that the fluorescence from the nanohybrid is strongly polarized with extinction ratios as high as 700 at room temperature. A statistical analysis of the 6T orientation inside BNNTs with inner diameter up to 1.5 nm shows that at least 80% of the encapsulated 6Ts exhibit a maximum deviation angle of less than 10{\deg} with respect to the BNNT axis. Despite a competition between molecule-molecule and molecule-BNNT adsorption in larger BNNTs, our results also show that more than 80% of the molecules display a preferential orientation along the BNNT axis with a deviation angle below 45{\deg}.

Published
2021

3. Using atomic interference to probe atom-surface interaction

Author

Marani, R., Cognet, L., Savalli, V., Westbrook, N., Westbrook, C. I., and Aspect, A.

Subjects
Physics - Atomic Physics
Abstract

We show that atomic interference in the reflection from two suitably polarized evanescent waves is sensitive to retardation effects in the atom-surface interaction for specific experimental parameters. We study the limit of short and long atomic de Broglie wavelength. The former case is analyzed in the semiclassical approximation (Landau-Zener model). The latter represents a quantum regime and is analyzed by solving numerically the associated coupled Schroedinger equations. We consider a specific experimental scheme and show the results for rubidium (short wavelength) and the much lighter meta-stable helium atom (long wavelength). The merits of each case are then discussed., Comment: 11 pages, including 6 figures, submitted to Phys. Rev. A, RevTeX source

Published
2000
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4. Properties of Microelectromagnet Mirrors as Reflectors of Cold Rb Atoms

Author

Drndic, M., Zabow, G., Lee, C. S., Thywissen, J. H., Johnson, K. S., Prentiss, M., Westervelt, R. M., Featonby, P. D., Savalli, V., Cognet, L., Helmerson, K., Westbrook, N., Westbrook, C. I., Phillips, W. D., and Aspect, A.

Subjects
Physics - Atomic Physics, Quantum Physics
Abstract

Cryogenically cooled microelectromagnet mirrors were used to reflect a cloud of free-falling laser-cooled 85Rb atoms at normal incidence. The mirrors consisted of microfabricated current-carrying Au wires in a periodic serpentine pattern on a sapphire substrate. The fluorescence from the atomic cloud was imaged after it had bounced off a mirror. The transverse width of the cloud reached a local minimum at an optimal current corresponding to minimum mirror roughness. A distinct increase in roughness was found for mirror configurations with even versus odd number of lines. These observations confirm theoretical predictions., Comment: Physical Review A, in print; 11 pages, 4 figures

Published
1999
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7. Optical Tools

Author

Roncali, E., Tavitian, B., Texier, I.e, Peltié, P., Perraut, F., Boutet, J., Cognet, L., Lounis, B., Marguet, D., Thoumine, O., Tramier, M., Boisseau, Patrick, editor, Houdy, Philippe, editor, and Lahmani, Marcel, editor

Published
2009
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9. A model of guided cell self-organization for rapid and spontaneous formation of functional vessels

Author

Andrique, L., Recher, G., Alessandri, K., Pujol, N., Feyeux, M., Bon, P., Cognet, L., Nassoy, P., Bikfalvi, A., Laboratoire Angiogenèse et Micro-environnement des Cancers (LAMC), Université Sciences et Technologies - Bordeaux 1-Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université de Bordeaux (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de la Santé et de la Recherche Médicale (INSERM), Nassoy, Pierre, and Recher, Gaelle

Subjects
Alginates, [PHYS.PHYS.PHYS-BIO-PH]Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], Myocytes, Smooth Muscle, Cell Line, Human Umbilical Vein Endothelial Cells, Humans, Vasoconstrictor Agents, Health and Medicine, Research Articles, ComputingMilieux_MISCELLANEOUS, Endothelin-1, Tissue Engineering, Tissue Scaffolds, [PHYS.PHYS.PHYS-BIO-PH] Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], Models, Cardiovascular, SciAdv r-articles, Hydrogels, Microfluidic Analytical Techniques, Coculture Techniques, Extracellular Matrix, Drug Combinations, Vasoconstriction, cardiovascular system, Blood Vessels, Proteoglycans, Collagen, Endothelium, Vascular, Laminin, Research Article
Abstract

We develop a new in vitro model of vessel formation involving guided self-assembly of cellular components of the vascular wall., Most achievements to engineer blood vessels are based on multiple-step manipulations such as manual sheet rolling or sequential cell seeding followed by scaffold degradation. Here, we propose a one-step strategy using a microfluidic coextrusion device to produce mature functional blood vessels. A hollow alginate hydrogel tube is internally coated with extracellular matrix to direct the self-assembly of a mixture of endothelial cells (ECs) and smooth muscle cells (SMCs). The resulting vascular structure has the correct configuration of lumen, an inner lining of ECs, and outer sheath of SMCs. These “vesseloids” reach homeostasis within a day and exhibit the following properties expected for functional vessels (i) quiescence, (ii) perfusability, and (iii) contractility in response to vasoconstrictor agents. Together, these findings provide an original and simple strategy to generate functional artificial vessels and pave the way for further developments in vascular graft and tissue engineering and for deciphering the angiogenesis process.

Published
2019
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11. Quantitative phase imaging with a 3D resolution equivalent to fluorescence: application to label-free biological tissue reconstruction

Author

Bon, P., Aknoun, S., Monneret, S., Lounis, B., Wattellier, B., Cognet, L., Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université de Bordeaux (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), PHASICS SA, École polytechnique (X), Institut FRESNEL (FRESNEL), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), and Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2015

18. Single molecule, CdSe/ZnS quantum dot and gold nanoparticle detection in live neurons - art. no. 609616

Author

Lasne, D., Cognet, L., BERCIAUD, S., Blab, G. A., Groc, L., Heine, M., Choquet, D., Lounis, B., Centre de physique moléculaire optique et hertzienne (CPMOH), Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1, Interdisciplinary Institute for Neuroscience, Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Osinski, M. and Yamamoto, K. and Jovin, and T. M.

Subjects
[PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS
Abstract

International audience; no abstract

Published
2006
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20. Single molecule imaging of glutamate receptor trafficking in neurons

Author

Choquet, D., Renner, M., Groc, L., Heine, M., Bats, C., Cognet, L., Modélisation et Identification en Automatique et Mécanique (MIAM), École Supérieure des Sciences Appliquées pour l'Ingénieur de Mulhouse (ESSAIM), Interdisciplinary Institute for Neuroscience, Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Centre de physique moléculaire optique et hertzienne (CPMOH), Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1, and Bergeret, Bernadette

Subjects
[PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract

International audience; no abstract

Published
2005

21. Dynamic of lipid traficking in neuronal synapses

Author

Renner, M., Cognet, L., Choquet, D., Bergeret, Bernadette, Modélisation et Identification en Automatique et Mécanique (MIAM), École Supérieure des Sciences Appliquées pour l'Ingénieur de Mulhouse (ESSAIM), Centre de physique moléculaire optique et hertzienne (CPMOH), and Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1

Subjects
[PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract

International audience; no abstract

Published
2005

23. Imaging single metal nanoparticles in cells by photothermal interference contrast

Author

Boyer, D., Tamarat, P., Cognet, L., Orrit, M., Lounis, B., Nicolau, D. V. and Enderlein, J. and Leif, R. C. and Farkas, D. L., Galilée (Galilée), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), Centre de physique moléculaire optique et hertzienne (CPMOH), Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1, Bergeret, Bernadette, and Nicolau, D. V. and Enderlein, J. and Leif, R. C. and Farkas, D. L.

Subjects
[PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract

International audience; no abstract

Published
2003

26. Glutamate receptors are mobile at synaptic sites as revealed by single molecule fluorescence microscopy

Author

Cognet, L., Tardin, C., Bats, C., Lounis, B., Choquet, D., Bergeret, Bernadette, Centre de physique moléculaire optique et hertzienne (CPMOH), and Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1

Subjects
[PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract

International audience; no abstract

Published
2002

27. Fenêtre spectrale sur le monde moléculaire

Author

Tamarat, P, Maali, Abdelhamid, Cognet, L, Lounis, B, Orrit, M, Centre de physique moléculaire optique et hertzienne (CPMOH), Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1, MoNOS, Huygens Laboratory, Universiteit Leiden [Leiden], and Bergeret, Bernadette

Subjects
[PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract

International audience; no abstract

Published
2001

35. Bouncing atoms: A coherent nano-probe.

Author

Westbrook, N., Savalli, V., Josse, V., Cognet, L., Featonby, P., Stevens, D., Westbrook, C. I., and Aspect, A.

Subjects
ATOMS, INTERFEROMETERS, ZEEMAN effect
Abstract

We describe experiments with atoms reflecting from atomic mirrors. We show that the Zeeman structure of the atoms permits the realization of an nano scale interferometer which can be used to probe the van der Waals interaction between an atom an a dielectric surface. We also discuss preliminary results on an experiment to observe sub-angstrom surface roughness using stimulated Raman transitions to achieve velocity selection of 0.3 times the single photon recoil velocity. This resolution corresponds to a 1.5 mrad maximum deviation in the effective reflecting surface. [ABSTRACT FROM AUTHOR]

Published
2001

36. Rebonds d'atomes froids sur un miroir magnétique

Author

Featonby, P. D., primary, Savalli, V., additional, Cognet, L., additional, Helmerson, K., additional, Westbrook, N., additional, Westbrook, C. I., additional, Phillips, W. D., additional, Aspect, A., additional, Zabow, G., additional, Drndic, M., additional, Lee, C., additional, Westervelt, R. M., additional, and Prentiss, M., additional

Published
2000
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40. Properties of microelectromagnet mirrors as reflectors of cold Rb atoms

Author

Drndić, M., primary, Zabow, G., additional, Lee, C. S., additional, Thywissen, J. H., additional, Johnson, K. S., additional, Prentiss, M., additional, Westervelt, R. M., additional, Featonby, P. D., additional, Savalli, V., additional, Cognet, L., additional, Helmerson, K., additional, Westbrook, N., additional, Westbrook, C. I., additional, Phillips, W. D., additional, and Aspect, A., additional

Published
1999
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41. Smoothing a current-carrying atomic mirror

Author

Cognet, L, primary, Savalli, V, additional, Featonby, P. D, additional, Helmerson, K, additional, Westbrook, N, additional, Westbrook, C. I, additional, Phillips, W. D, additional, Aspect, A, additional, Zabow, G, additional, Drndić, M, additional, Lee, C. S, additional, Westervelt, R. M, additional, and Prentiss, M, additional

Published
1999
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44. New Physics with Evanescent Wave Atomic Mirrors: The van der Waals Force and Atomic Diffraction

Author

Westbrook, N., primary, Westbrook, C. I., additional, Landragin, A., additional, Labeyrie, G., additional, Cognet, L., additional, Savalli, V., additional, Horvath, G., additional, Aspect, A., additional, Hendel, C., additional, Moelmer, K., additional, Courtois, J.-Y., additional, Phillips, W. D., additional, Kaiser, R., additional, and Bagnato, V., additional

Published
1998
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50. Mesures de la qualité des rivières : stations automatiques

Author

Journet, J. M., Randon, G., Odier, M., Lutz, M., Cognet, L., Journet, J. M., Randon, G., Odier, M., Lutz, M., and Cognet, L.

Abstract

Les stations automatiques sont souvent utilisées comme stations d'alerte pour la protection des prises d'eau potable ou constituent des outils puissants d'étude et de modélisation des phénomènes naturels et des processus de traitement. Ces aspects et les différentes techniques seront abordés au travers de réalisations récentes. Les stations automatiques sont malheureusement encore peu développées compte tenu, notamment, de leur coût, des difficultés technologiques, des moyens humains nécessaires, de la réglementation insuffisante, etc. Le développement de ce type d'instrumentation, passe par une ouverture des constructeurs français vers le marché extérieur ainsi que par une réglementation accrue ; de plus, la recherche de nouveaux capteurs globaux est nécessaire pour couvrir un plus grand nombre d'éléments chimiques tout en évitant de multiplier les appareils.

Published
1987
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