HAL Portal ESPCI (Ecole Supérieure de Physique et de Chimie Industrielles)
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A multidisciplinary approach to the home management of continuous positive airway pressure therapy for obstructive sleep apnea: beyond usual care pathways (a narrative review)
No full textInternational audienc
Immune cell infiltration of patient derived glioblastoma cell spheroids in acoustic levitation in bulk acoustic wave devices.
No full textInternational audienceAn acousto-fluidic bioreactor allowing the culture of patient-derived gliobastoma tumoroids in acoustic levitation and model immune cell infiltration using the transverse acoustic radiation force in the levitation plane
Size-Dependent Optical Properties of CdSe/CdS/ZnS Nanocrystal Aggregates Encapsulated in a Gold Nano-resonator: A Comprehensive Study
No full textInternational audienceThis paper explores gold resonator effects on the optical properties of chemically synthesized clusters of CdSe/CdS/ZnS nanocrystals. To reduce optical losses, the gold is sputtered on the aggregates already embedded in a thin silica shell. This technique also allows to compare optical properties (radiation rate, far field emission) of single aggregates of different diameters before and after gold deposition. Experimental results are supported by Finite-Difference Time Domain (FDTD) simulations to understand the size dependent behavior and the role of dipolar and quadrupolar plasmon resonances
An integrated multi-instrument methodology for studying marginal ice zone dynamics and wave-ice interactions
No full textWave-driven fragmentation is the key mechanism shaping the Marginal Ice Zone (MIZ). Capturing this process is therefore essential for improving sea ice models, which currently do not fully capture the complex interactions between the forcing imposed by waves and the nonlinear dynamics of the resulting sea ice breakup and deformation. To investigate these interactions, we introduce a comprehensive multi-instrument dataset from a field campaign in the MIZ of the St. Lawrence Estuary, Canada, designed to characterize wave propagation and mechanical properties of sea ice under natural forcing conditions. The dataset integrates synchronized measurements from geophone arrays, wave buoys, smartphones configured as motion sensors, and unmanned aerial vehicles (UAVs), all collected during coordinated deployments across diverse ice types and sea states. Seismic data, recorded with geophone arrays, enable estimation of the ice thickness and elastic properties via active and passive wavefield analyses. Concurrently, wave buoys and smartphones capture ocean wave characteristics including amplitude, wavelength, and attenuation near ice edges. UAV imagery is processed with advanced methods to detect vertical ice displacements with sub-centimetre sensitivity, allowing extraction of wave dispersion relations in different ice conditions. Preliminary analyses demonstrate strong agreement between independent measurement methods, validating the dataset’s quality. This multi-sensor approach offers unique opportunities to improve our understanding of wave-ice interactions, wave attenuation, and fracture dynamics in situ, thus offering a valuable resource for the sea ice and oceanographic research community to gain insight in wave-induced ice break-up mechanisms under natural conditions
Midbrain dopamine D2R regulates the salience of threat-related events
No full textInternational audienceSalience attributed to stimuli predicting rewarding or aversive outcomes is critical for adaptive behavior. Dopamine (DA)-neurons play a central role in this process by modulating responses to both rewarding and aversive cues. DA-neurons are tightly and readily modulated by DA D2 autoreceptors (autoD2Rs), but their role in regulating responses to aversive stimuli remains unclear. In this study, we investigated the role of autoD2R in regulating the activity of VTA DA-neurons in response to salient aversive stimuli. Using Drd2 Slc6a3 mice, in which Drd2 is selectively deleted in DA-neurons, we observed enhanced excitatory and inhibitory responses of VTA DA-neurons to aversive stimuli, suggesting that autoD2R acts as a critical regulatory brake. Importantly, this modulation occurred independently of either the pacemaker activity of DA-neurons or their coupling to the non-selective sodium leak channel NALCN. Behaviorally, Drd2 Slc6a3 male mice showed enhanced discrimination between threat-predicting and non-predicting cues that persisted during extinction learning, highlighting a sex-biased role of autoD2R in threat processing. Our results provide new mechanistic insights through which autoD2R influence behavioral responses to aversive stimuli, with implications for understanding neuropsychiatric disorders characterized by maladaptive threat processing
Rare-event detection in a backward-facing-step flow using live optical-flow velocimetry: observation of an upstream jet burst
No full textInternational audienceRare and extreme events in turbulent flows play a critical role in transport, mixing and transition, yet are notoriously difficult to capture experimentally. Here we report, to our knowledge, the first direct experimental detection of an upstream-directed jet burst in a backward-facing step (BFS) flow at , using long-duration Live Optical Flow Velocimetry (L-OFV). Continuous monitoring over 1.5 h enabled a data-driven definition of extremes as rare velocity probes excursions deep into the observed distribution's tails; in practice, large negative events (u: Z < -6, v: Z < -5 at , where |Z| > > 0 stands for large deviations from the mean value) triggered the live capture of surrounding velocity fields. The recording is triggered when the probes surpass the defined threshold, using live analysis of the velocity fields. The detected event features a jet-like intrusion into the recirculation region initiated by the collapse of a merged Kelvin-Helmholtz vortex and sustained by counter-rotating vortices, and is accompanied with heavy-tailed probe statistics and simultaneous amplification of fluctuating kinetic energy and enstrophy. While a single event was recorded, underscoring its rarity, the results establish L-OFV as a viable platform for rare-event detection in separated shear layers and document a previously unreported mechanism of upstream jet bursting in BFS flow
Nuclear translocation of the LINE-1 encoded ORF1 protein alters nuclear envelope integrity in human neurons
No full textInternational audienceLINE-1 retrotransposons are increasingly implicated in aging and neurodegenerative diseases, yet the precise pathogenic mechanisms remain elusive. While the endonuclease and reverse transcriptase activities of LINE-1encoded ORF2p can induce DNA damage and inflammation, a role of LINE-1 ORF1p in cellular dysfunctions stays unassigned. Here we demonstrate, using a neuronal cellular model, that ORF1p translocates into the nucleus upon arsenite-induced stress, directly interacting with nuclear import (KPNB1), nuclear pore complex (NUP153), and nuclear lamina (Lamin B1) proteins. Nuclear translocation of ORF1p disrupts nuclear integrity, nucleocytoplasmic transport, and heterochromatin structure, features linked to neurodegeneration and aging. Elevated nuclear ORF1p levels induced either by arsenite-induced stress, ORF1p overexpression, or as observed in Parkinson's disease post-mortem brain tissues correlate with impaired nuclear envelope (NE) morphology. Stress-induced nuclear alterations are mitigated by blocking ORF1p nuclear import or with the anti-aging drug remodelin. This study thus reveals a pathogenic action of nuclear ORF1p in human neurons driving NE alterations and thereby contributing to LINE-1-mediated cell toxicity
Mathematical modeling of the feather follicle morphogenetic wave in birds
No full textInternational audienceDuring the development of the avian skin, feather follicles are produced in a medio-lateral morphogenetic wave that results in their spatial arrangement in typical patterns. This wave involves the timely acquisition of pattern-forming competence followed by a row-by-row produc tion of feather follicles. While several mathematical models combining self-organizing systems accurately reproduced dynamics of feather follicle pattern formation, the events that control timely parameters of wave propagation remain poorly understood. Here, we built on previous modeling work to theoretically calculate the speed at which tissue competence progresses. Using a weakly non-linear analysis, we calculated the speed at which follicles emerge once competence is attained. We produced numerical simulations of our model to predict the respective influences of competence acquisition and follicle emergence on each other and on wave propagation. Our results show that the theoretical speed of follicle emergence is limited by competence acquisition, but that, in turn, competence acquisition is not constrained by follicle emergence. This modeling work provides an approximation of the timely parameters of the morphogenetic wave, and sheds light on the interplay between competence and patterning events in the developing skin
A Focus on the Emission of Volatile Organic Compounds (VOCs) from Raw Materials Potentially Used in Human Odor Sampling
No full textInternational audienceThe present study provided an exhaustive examination of VOC emissions originating from 13 different raw materials susceptible to being used in the sampling of the human volatilome and encompassing both polymeric and non-polymeric compositions. To achieve this aim, thermodesorption coupled with comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (TD-GC×GC/ToFMS) was employed. For each material, we report the total number of detected peaks, total volatile organic compound (TVOC) concentration, distribution of VOC emissions across different chemical families, minimum and maximum individual concentrations, as well as hypotheses regarding the origins of some specific VOCs depending on the material considered. The findings from this investigation revealed that materials, such as silicone and polyurethane, could emit an extensive array of VOCs, with up to 2000 chromatographic peaks detected, and emissions of total volatile organic compounds (TVOCs) reaching levels of 5.4 µg·g−1 and 9.8 µg·g−1, respectively. In the case of polyamide, some VOCs could be related to potential reagents involved in its synthesis. While highlighting materials that should be used with caution depending on the topic and target analytes, this study identified materials that exhibited minimal VOC emissions, such as polytetrafluoroethylene, aluminum, and stainless steel, after an adequate conditioning step. The selected analytical technique, TD-GC×GC/ToFMS, proved its relevance to identify and characterize semi-quantitatively VOC emissions coming from those materials. Such information was essential within the frame of the development of a body odor sampling system, our primary objective
Ultrasound matrix imaging for 3D transcranial in vivo localization microscopy
No full textInternational audienceTranscranial ultrasound imaging is usually limited by skull-induced attenuation and high-order aberrations. By using contrast agents such as microbubbles in combination with ultrafast imaging, not only can the signal-to-noise ratio be improved, but super-resolution images down to the micrometer scale of the brain vessels can also be obtained. However, ultrasound localization microscopy (ULM) remains affected by wavefront distortions that limit the microbubble detection rate and hamper their localization. In this work, we show how ultrasound matrix imaging, which relies on the prior recording of the reflection matrix, can provide a solution to these fundamental issues. As an experimental proof of concept, an in vivo reconstruction of deep brain microvessels is performed on three anesthetized sheep. The compensation of wave distortions is shown to markedly enhance the contrast and resolution of ULM. This experimental study thus opens up promising perspectives for a transcranial and nonionizing observation of human cerebral microvascular pathologies, such as stroke