COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Cristaux photoniques et plasmoniques, couplage à des émetteurs fluorescents

PARIS-BIUSJ-Biologie recherche (751052107) / SudocSudocFranceF

Hormones and fertility.

No abstract availabl

Fourier-imaging of single self-assembled CdSe nanoplatelet chains and clusters reveals out-of-plane dipole contribution

International audienceFluorescent semiconductor nanoplatelets (epitaxial quantum wells) can be synthesized with excellent monodispersity and self-assembled in highly-ordered structures. Modifications of their electronic and luminescence properties when stacked, due to strong mechanical, electronic or optical interactions between them, have been the topic of intense recent discussions. In this paper, we use Fourier imaging to measure the different dipole components of various nanoplatelet assemblies. By comparing different measurement conditions and corroborating them with polarimetric analysis, we confirm an excellent precision on the dipole components. For single nanoplatelets, only in-plane dipoles (parallel to the platelet plane) are evidenced. For clusters of 2-10 platelets and chains of 30-300 platelets, on the other hand, a clear out-of-plane dipole component is demonstrated. Its contribution becomes more significant as the number of platelets is increased. We review possible explanations and suggest that the added out-of-plane dipole can be induced by strain-induced nanoplatelet deformations

Active control of radiation beaming from Tamm nanostructures by optical microscopy

International audienceActive control of the radiation orientation (beaming) of a metallic antenna has been reported by various methods, where the antenna excitation position was tuned with a typical 50 nm precision by a near-field tip or an electron-beam. Here we use optical microscopy to excite and analyze the fluorescence of a layer of nanocrystals embedded in an optical Tamm state nanostructure (metallic disk on top of a Bragg mirror). We show that the radiation pattern can be controlled by changing the excitation spot on the disk with only micrometer precision, in a manner which can be well described by numerical simulations. A simplified analytical model suggests that the propagation length of the in-plane confined optical modes is a key parameter for beaming control

Single Gold Bipyramid Nanoparticle Orientation Measured by Plasmon-Resonant Scattering Polarimetry

International audienceThe 3D orientation of a single gold nanoparticle is probed experimentally by light scattering polarimetry. We choose high-quality gold bipyramids (AuBPs) that support around 700 nm a well-defined narrow longitudinal localized surface plasmonic resonance (LSPR) which can be considered as a linear radiating dipole. A specific spectroscopic dark-field technique was used to control the collection angles of the scattered light. The in-plane as well as the out-of-plane angles are determined by analyzing the polarization of the scattered radiation. The data are compared with a previously developed model where the environment and the angular collection both play crucial roles. We show that most of the single AuBPs present an out-of-plane orientation consistent with their geometry. Finally, the fundamental role of the collection angles on the determination of the orientation is investigated for the first time. Several features are then deduced: we validate the choice of the analytical 1D model, an accurate 3D orientation is obtained, and the critical contribution of the evanescent waves is highlighted

3D Orientation of Single Gold Bipyramid Measured by Scattering Polarization pectroscopy:Role of the Numerical Aperture

International audienceThe 3D orientation of a single gold nano-bipyramid (AuBPs) on a glass substrate is successfully measured by polarimetric analysis of its scattering. The AuBPs are very attractive due to the presence of hot spots at their end tips resulting from a strong longitudinal localized surface plasmon resonance. In addition, this resonance can be modeled as a radiating dipole. To study the 3D orientation, we designed a specific spectroscopic dark-field microscope with a precise control of the collection angles of the scattering in the Fourier plane. The 3D angles are resolved by analyzing the polarization of the AuBP scattering. Simulations are used to extract the inplane and out-of-plane angles with a very good accuracy of 3 %. In particular, the critical role of the numerical aperture collection was investigated experimentally by Fourier filtering of the scattering into the back focal plane of the objective. It reveals a physical insight into the contribution of the evanescence waves and provides a technical guideline for choosing the collection objective for polarimetric measurements

3D Orientation of Single Gold Bipyramid Measured by Scattering Polarization pectroscopy:Role of the Numerical Aperture

International audienceThe 3D orientation of a single gold nano-bipyramid (AuBPs) on a glass substrate is successfully measured by polarimetric analysis of its scattering. The AuBPs are very attractive due to the presence of hot spots at their end tips resulting from a strong longitudinal localized surface plasmon resonance. In addition, this resonance can be modeled as a radiating dipole. To study the 3D orientation, we designed a specific spectroscopic dark-field microscope with a precise control of the collection angles of the scattering in the Fourier plane. The 3D angles are resolved by analyzing the polarization of the AuBP scattering. Simulations are used to extract the inplane and out-of-plane angles with a very good accuracy of 3 %. In particular, the critical role of the numerical aperture collection was investigated experimentally by Fourier filtering of the scattering into the back focal plane of the objective. It reveals a physical insight into the contribution of the evanescence waves and provides a technical guideline for choosing the collection objective for polarimetric measurements

Polarimetric dark-field spectroscopy of gold bipyramids: measuring single particle 3D orientation

International audienceWe determine the 3D orientation of single gold nano-bipyramids (AuBPs) deposited on a glass substrate. These nanoparticles possess a well-defined localized surface plasmon resonance along their main axis which can be modeled as a single dipole. Orientation is deduced by polarization resolved dark-field scattering. For that purpose, a specific experiment has been built to select, analyze in polarization and resolve the scattering angles at the single nanoparticle level. Usually, the out-of-plane angle is deduced by measuring the degree of polarization (DOP) and doing numerical simulations taking into account the nature of the dipole (1D, 2D) and all experimental parameters. We compare this method with a complete measurement of the DOP as function of the collected numerical aperture (controlled by Fourier filtering). The results provide the accuracy of the polarimetric measurements. The complimentary method proposed in this article can easily be extended to more complex system

Dégâts de géomyze sur maïs analyse des facteurs de risque

National audienceContexte : Les attaques de géomyze, un ravageur du maïs, sont variables d'une année à l'autre, et peuvent être très nuisibles (dans l'ouest de la France en 2016). Face à l'interdiction des outils de lutte efficaces (traitements de semences néonicotinoïdes), des moyens de compréhension et de prévision sont recherchés. Travail : une enquête réalisée en Bretagne a révélé qu'aucun facteur agronomique n'avait influencé les dégâts en 2016, ce qui suggère l'influence des facteurs climatiques annuels. Une recherche de tels facteurs a été réalisée. Résultats : quatre facteurs ont été identifiés, dont trois intervenants avant les semis (dans l'été et l'hiver précédent). Un modèle descriptif et un prototype de modèle prédictif ont été élaborés. Le travail doit continuer