HAL Portal ESPCI (Ecole Supérieure de Physique et de Chimie Industrielles)
Not a member yet
13939 research outputs found
Sort by
Spectroscopic investigations into the dyeing properties of wild silks
No full textInternational audienc
Influenza vaccine effectiveness and genetic diversity: insights from end-of-season community surveillance, France, 2024-2025
No full textInternational audienceInfluenza 2024-2025 season in France was characterized by prolonged duration, unusual co-circulation of all three viruses (A(H1N1)pdm09, A(H3N2), B/Victoria) with several subclades, and substantial healthcare impact. We aimed to investigate the impact of influenza genetic diversity on vaccine effectiveness (VE).A test-negative design study was conducted to estimate VE in a large cohort from the RELAB network of community-based laboratories (n = 77,704 patients). A subset of sequenced samples (n = 2,119 patients) allowed VE estimation for several clades and subclades as well as comparison of subclade distribution by vaccination status.Vaccine coverage was 45% in patients aged 65 years and older (65+). VE based on PCR-confirmed infections was 44% (95% CI: 41-48%) and lower in 65+ individuals, at 25% (95% CI:18-31%) especially for type A virus (23%; 95% CI: 13-32%) compared to type B virus (57%; 95% CI: 35-72%).Sequencing-confirmed VE among individuals vaccinated 15 days to 3 months prior testing, was 41% (95% CI: 14-60%) for A(H1N1)pdm09 and 47% (95% CI: 21-64%) for its main subclade 5a.2a(C.1.9.3); A(H3N2) estimate was 30% (95% CI:5-48%) and 31% (95% CI:4-50%) for 2a.3a.1(J.2) sublclade. The emerging A(H1N1)pdm09 5a.2a.1 (D.3) subclade was significantly more frequent among vaccinated individuals compared to unvaccinated.The low vaccine coverage combined with the notably low effectiveness against A(H3N2) and for type A in elderly may have contributed to the high influenza activity this season. The emergence of A(H1N1)pdm09 5a.2a.1 (D.3) raises uncertainty and requires surveillance.</p
Self /other recognition and distinction in adolescents with anorexia nervosa: A pilot study using a double mirror paradigm
No full textInternational audienceBackground: Abnormalities in body perception in patients affected by anorexia nervosa have been widely studied, but without explicit reference to their relationship to others and the social processes involved. Yet, there are a several arguments supporting impairments in interpersonal relationships in these patients. Notably, some evidence suggests that self/other distinction (SOD), the ability to distinguish one's own body, actions and mental representations from those of others could be impaired. But research remains scarce in this area.Material and methods: A single-centre, prospective pilot study was conducted to investigate, for the first time, self-recognition and SOD in seven adolescents with anorexia nervosa compared with matched healthy controls (HCs) using the "Alter Ego"TM double mirror paradigm. This innovative device allows the progressive morphing of one's own face to that of another and vice versa between two subjects that interact on opposite sides of the device. Two judgement criteria were used: 1) M1: the threshold at which subjects start to recognize their own face during other-to-self morphing, and 2) M2: the threshold at which subjects start to recognize the other's face during self-to-other morphing. In a second part, SOD was reassessed during five different sensorimotor tasks aimed at increasing body self-consciousness in participants with anorexia nervosa.Results: The results showed that the participants with anorexia nervosa exhibited earlier self-recognition in the other-to-self sequence and delayed other-recognition in the self-to-other sequence. Furthermore, in contrast with that of HCs, the critical threshold for switching between self and other varied with the direction of morphing in anorexia nervosa participants. Finally, when participants with anorexia were seated in a chair with a backrest and footrest strengthening the median axis of their body, the self-recognition threshold (M1) increased significantly, approaching that of controls.Conclusions: Although additional research is needed to replicate the results of this pilot study, it revealed the first behavioural evidence of altered SOD in individuals affected by anorexia nervosa through an embodied, semiecological face-recognition paradigm. The relationships between anomalies in body perception and alterations in interpersonal relationships are discussed within an integrative framework from phenomenology to neuroscience, and new research and therapeutic perspectives are presented
Décodage in situ guidé par nanothermométrie de la dégradation des cellules solaires à pérovskite sous contrainte optique
No full textInternational audienceThe operational instability of perovskite solar cells (PSCs) remains a key obstacle to their long-term performance and commercial deployment. While extensive efforts have been made to understand degradation mechanisms, direct probing of the buried interfaces, where critical degradation often initiates, has remained elusive. In this work, we introduce a new in situ methodology that harnesses the nanothermometric properties of embedded upconversion nanoparticles (UCNPs) placed at the buried perovskite/hole transport layer (HTL) interface. This approach allows, for the first time, real-time tracking of local interfacial temperature evolution during light-induced accelerated degradation, while simultaneously monitoring the device's optical and photovoltaic performance. Applied to PSCs with different perovskite compositions, this technique reveals non-trivial thermal signatures and distinct degradation regimes correlated with structural and optical changes observed via ex situ characterizations. The results uncover a dynamic interplay between heat accumulation, phase transformation, and material decomposition, offering insights into the spatiotemporal evolution of PSC degradation. Our work demonstrates that nanoscale thermal sensing at buried interfaces provides a powerful new diagnostic tool to elucidate the internal degradation pathways of perovskite solar cells
Flip‐Chip Integration of the Superconducting Quantum‐Classical Circuits: Coupling Types
No full textInternational audienc
D-shaped body wake control through flexible filaments
No full textInternational audienceIn this study, we investigate the flow around a canonical blunt body, specifically a D-shaped body of width D, in a closed water channel. Our goal is to explore near-wake flow modifications when a series of rigid and flexible plates (l = 1.8D) divided into filaments (h = 0.2D) are added. We focus on assessing the interaction between the flexible filaments and the wake dynamics, with the aim of reducing the recirculation bubble and decreasing the velocity deficit in the wake. To achieve this, we conduct a comparative study varying the stiffness and position of the filaments at different flow velocities. The study combines Particle Image Velocimetry (PIV) measurements in the wake behind the body with recordings of the deformation of the flexible filaments. Our observations show that the flexible filaments can passively reconfigure in a two-dimensional fashion, with a mean tip deflection angle that increases with the incoming flow velocity. Deflection angles up to approximately ∼ 9 • and vibration tip amplitude of around ∼ 4 • are achieved for flow velocities U * ≃ fnD/u∞ ≥ 1.77, where fn is the natural frequency of the flexible filaments. This reconfiguration results in a reduction of the recirculation bubble and a decrease in the velocity deficit in the wake compared to the reference and rigid cases. In addition, curved filaments with a prescribed rigid deformation exhibit very similar behavior to that of flexible filaments, indicating that the vibration of flexible filaments does not significantly disturb the wake. The obtained results highlight the interest of testing flexible appendages in the wake of blunt bodies for designing effective flow control devices
Supercritical fluid technology to the formulation of quercetin amorphous solid dispersions
No full textInternational audienc
Reconnaissance d'arcs de défaut dans les aéronefs par apprentissage artificiel
No full textIn the aeronautical field, the appearance of an electric arc, either in "series" or in "parallel" with the loads, is considered to be a problematic event. Its consequences can be synonymous of major damages to devices or structures. They can also be unavoidable but controlled, as is the case in cut-off systems when a contact opens for example. In the case of unwanted arcs, related to faults, detecting their presence as quickly as possible is a major challenge. Their destructive capacity is directly related to the voltage and power of the aircraft distribution network. However, the power required by embedded systems has increased considerably and is expected to grow even more in the next years towards more electric aircraft. Consequently, safety measures must be taken to recognize arc faults and cut off the power supply as quickly as possible when it occurs. Many devices capable of detecting arc faults are currently available. They are mainly based on the recognition of electrical signatures resulting from numerous tests carried out according to precise protocols. However, whatever the solutions proposed, their robustness in an aeronautical environment is low given the existence of too many "false positives". Reliable, robust and rapid detection is even more necessary as the electrical power (voltage and current levels) continues to increase for both propulsive and non-propulsive applications. The purpose of this thesis is the use of different machine learning classification methods in order to recognize the presence of electric arc faults, in particular DC series arcs due to their difficult recognition. The methodology described in this report proposes the use of a feature extraction technique followed by a selection of the most relevant ones in order to build a classifier from the proposed algorithms. The latter has been tested under different conditions and has shown itself capable of achieving reliability, robustness and detection time rates that are very satisfactory for the application case.Dans le domaine de l'aéronautique, l'apparition d'un arc électrique (qu'il soit « série » ou « parallèle ») est un événement redouté. Ses conséquences peuvent être synonymes d'endommagement majeur des systèmes ou des structures. Ils peuvent aussi être inévitables mais maitrisés, comme dans les systèmes de coupure, lors de l'ouverture d'un contact par exemple. Dans le cas d'arcs indésirables liés à des défauts, détecter leur présence le plus rapidement possible afin de les couper constitue donc un enjeu majeur. L'énergie et la capacité destructrice des arcs sont directement liées à la puissance du réseau de distribution des avions. Or, la puissance requise par les systèmes électriques embarqués a augmenté considérablement et devrait continuer à augmenter encore plus dans les années à venir. En effet, le monde aéronautique évolue vers des avions plus électriques. Par conséquent, des mesures de sécurité doivent être prises pour reconnaitre les arcs de défauts et couper l'alimentation le plus rapidement possible lorsque cela se produit. De nombreux dispositifs susceptibles d'effectuer la détection d'arcs électriques sont actuellement disponibles. Ils reposent sur l'utilisation et la reconnaissance de « signatures » principalement électriques et issues de nombreux essais réalisés selon des protocoles précis. Malgré tout, quelles que soient les solutions proposées, leur robustesse dans un environnement aéronautique n'est pas satisfaisante compte tenu de l'existence de « faux positifs ». Une détection fiable, robuste et rapide s'avère d'autant plus nécessaire que la puissance électrique (niveaux de tension et de courant) ne cesse d'augmenter tant pour les applications propulsives que non propulsives. L'objectif de cette thèse est de proposer l'utilisation de différentes méthodes de classification par apprentissage artificiel dans le but de reconnaitre la présence des arcs électriques de défaut, en particulier les arcs série en DC en raison de leur difficulté de reconnaissance. La méthodologie décrite dans ce rapport propose l'utilisation d'une technique d'extraction de descripteurs suivie d'une sélection des plus pertinents pour ensuite construire un classifieur à partir des algorithmes proposés. Ce dernier a été testé dans des différentes conditions et s'est montré capable atteindre des taux de fiabilité, robustesse et temps de détection très satisfaisants pour le cas d'application
Electrocatalytic CO<sub>2</sub> to CO and Methanol Conversion Using a Molecular Cobalt Corrole Complex
No full textInternational audienceTriphenylcorrole (Cor)Co III (DMSO), (Cat 1), was investigated for its electrochemical CO₂ reduction catalysis, facilitating 2-, 4-, and 6-electron transfer processes. Cat 1 was identified as an active molecular catalyst for CO₂-to-CO (2e⁻, 2H⁺) conversion under homogeneous conditions in CH3CN, using water as the proton source. Under heterogeneous conditions, Cat 1@E (Cat 1 immobilized on multi-walled carbon nanotubes (MWCNTs) and coated on carbon paper) demonstrated CO2-to-CO conversion with near-perfect Faradaic efficiency (FECO) ~97%, and high stability at near-neural pH in single-cell setup. When the electrode was transitioned to a flow-cell configuration, the jCO significantly improved to 47.5 ± 0.5 mA cm⁻², while maintaining a high FECO of ~95%. Applying a higher jtot of -200 mA cm⁻², led to the formation of CH3OH (6e⁻, 6H⁺) with FECH3OH of ~2%, representing a sevenfold increase compared to the single-cell configuration (FECH3OH ~0.34%) and jCH3OH of ~3.84 mA cm⁻² with trace amounts of HCHO (4e⁻, 4H⁺) in parallel. Metal-bound CO, i.e., [M n+ -CO], was identified as a key intermediate for CH3OH formation, as replacing CO2 with CO in the feed gas further promotes the FE of the liquid products, reaching ~4 to 5% for both CH3OH and HCHO under a singlecell configuration. The demonstration that simple Co corrole can drive CO2RR up to 6 electrons illustrates that multi proton-electrons activation with molecular catalysts is a more general possibility than anticipated
Synthèse et caractérisation de nanoplaquettes de Cu2-xSe atomiquement plates et de boites quantiques d'Ag2Se
No full textThe colloidal synthesis of semiconductor nanocrystals has been extensively developed for various shapes and dimensions, yet certain materials remain challenging to access.The first objective of my thesis work was to explore synthesis via cation exchange, demonstrating that surface chemistry acts as a powerful lever to tune the kinetics and thermodynamics of the process. In my work, I considered the exchange from highly anisotropic cadmium chalcogenide NPLs to copper (I) chalcogenides, both with cubic structures. As the pristine ligands exert in-plane tensile stress on the surface, the lattice mismatch between the initial and final structures increases, causing the NPLs to lose their 2D shape upon cation exchange. On the other hand, CdSe NPLs capped with in-plane compressive stress thiolate ligands preserve their shape.The second objective of my project was to develop heavy-metal-free nanocrystals with tunable properties in the shortwave infrared (SWIR) region. I optimized the colloidal synthesis of Ag₂Se nanocrystals (NCs), a promising alternative to HgSe, to achieve size-tunable optical properties and enhance their photoluminescence through shell growth. Additionally, these nanocrystals were integrated into dielectric microcavities to narrow their photoluminescence features, paving the way for applications in SWIR light-emitting devicesLa synthèse colloïdale de nanocristaux de semi-conducteurs a été largement développée pour obtenir diverses formes et dimensions de matériaux, mais certains restent difficiles à obtenir par cette voie.Le premier objectif de mes travaux de thèse a été d’explorer la synthèse via l’échange cationique, en démontrant que la chimie de surface constitue un levier puissant pour ajuster la cinétique et la thermodynamique du processus. J’ai étudié l’échange à partir de nanoplaquettes (NPLs) de chalcogénures de cadmium, anisotropes, pour obtenir des chalcogénures de cuivre (I), tous deux de structure cubique. Les ligands natifs exercent une contrainte de dilatation sur la surface, ce qui augmente le désaccord de réseau entre les structures initiale et finale, provoquant ainsi la perte de la forme 2D des NPLs lors de l’échange cationique. En revanche, les NPLs de CdSe recouvertes de ligands thiolates, qui exercent une contrainte de compression, conservent leur forme.Le second objectif de mon projet a été de développer des nanocristaux exempts de métaux lourds avec des propriétés ajustables dans l’infrarouge à ondes courtes. J’ai optimisé la synthèse colloïdale des nanocristaux d’Ag₂Se (NCs), une alternative prometteuse à HgSe, pour obtenir des propriétés optiques ajustables en fonction de leur taille et améliorer leur photoluminescence par la croissance de coque. De plus, ces nanocristaux ont été dans des microcavités diélectriques pour affiner leurs caractéristiques de photoluminescence, ouvrant ainsi la voie à des applications pour des diodes électroluminescente