Université Paris-Saclay

About: Université Paris-Saclay is a education organization based out in Gif-sur-Yvette, France. It is known for research contribution in the topics: Population & Context (language use). The organization has 29307 authors who have published 43183 publications receiving 867404 citations.

Plasmon-exciton-polariton lasing

Abstract: Metallic nanostructures provide a toolkit for the generation of coherent light below the diffraction limit. Plasmonic-based lasing relies on the population inversion of emitters (such as organic fluorophores) along with feedback provided by plasmonic resonances. In this regime, known as weak light–matter coupling, the radiative characteristics of the system can be described by the Purcell effect. Strong light–matter coupling between the molecular excitons and electromagnetic field generated by the plasmonic structures leads to the formation of hybrid quasi-particles known as plasmon-exciton-polaritons (PEPs). Due to the bosonic character of these quasi-particles, exciton-polariton condensation can lead to laser-like emission at much lower threshold powers than in conventional photon lasers. Here, we observe PEP lasing through a dark plasmonic mode in an array of metallic nanoparticles with a low threshold in an optically pumped organic system. Interestingly, the threshold power of the lasing is reduced by increasing the degree of light–matter coupling in spite of the degradation of the quantum efficiency of the active material, highlighting the ultrafast dynamic responsible for the lasing, i.e., stimulated scattering. These results demonstrate a unique room-temperature platform for exploring the physics of exciton-polaritons in an open-cavity architecture and pave the road toward the integration of this on-chip lasing device with the current photonics and active metamaterial planar technologies.

Measurement of the CP-violation parameter Re( epsilon '/ epsilon ).

Abstract: A measurement of the [ital CP]-violation parameter Re([var epsilon][prime]/[var epsilon]) has been made using the full E731 data set. We find Re([var epsilon][prime]/[var epsilon])=(7.4[plus minus]5.2[plus minus]2.9)[times]10[sup [minus]4] where the first error is statistical and the second systematic.

Randomized Phase III Trial of Temsirolimus and Bevacizumab Versus Interferon Alfa and Bevacizumab in Metastatic Renal Cell Carcinoma: INTORACT Trial

Abstract: Purpose To prospectively determine the efficacy of combination therapy with temsirolimus plus bevacizumab versus interferon alfa (IFN) plus bevacizumab in metastatic renal cell carcinoma (mRCC). Patients and Methods In a randomized, open-label, multicenter, phase III study, patients with previously untreated predominantly clear-cell mRCC were randomly assigned, stratified by prior nephrectomy and Memorial Sloan-Kettering Cancer Center prognostic group, to receive the combination of either temsirolimus (25 mg intravenously, weekly) or IFN (9 MIU subcutaneously thrice weekly) with bevacizumab (10 mg/kg intravenously, every 2 weeks). The primary end point was independently assessed progression-free survival (PFS). Results Median PFS in patients treated with temsirolimus/bevacizumab (n = 400) versus IFN/bevacizumab (n = 391) was 9.1 and 9.3 months, respectively (hazard ratio [HR], 1.1; 95% CI, 0.9 to 1.3; P = .8). There were no significant differences in overall survival (25.8 ν 25.5 months; HR, 1.0; P = .6) ...

Detergent structure in crystals of a bacterial photosynthetic reaction centre

Abstract: RECENT evidence shows that membrane-bound proteins can be crystallized successfully in the presence of detergent1-3, which seems to facilitate the ordered packing of the proteins by binding to their hydrophobic surfaces in micellar manner4,5. This approach has enabled the molecular structures of two bacterial photosynthetic reaction centres to be solved at high resolution by X-ray crystallography6-9, each of which has provided insights into the mechanism of photo-activated electron transport across the cell membrane. The detergent, however, although present in high concentration in the crystals, is not seen in these high-resolution structures because of disordering. To determine the structural motifs formed by the detergent that are involved in crystal packing, we have therefore generated a low-resolution structure using neutron diffraction with contrast variation. We find that the detergent is concentrated in rings which fill all the available space around the membrane-spanning α-helices of the reaction-centre protein subunits L, M and H. These rings are interconnected throughout the crystal lattice by short cylindrical detergent bridges such that zig-zag chains are formed parallel to the c direction. The average structure of the detergent therefore is spatially complementary to the structure of the reaction-centre complex and provides a model for the interaction between the lipid bilayer and the complex in vivo.