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Évolution des répercussions psychologiques de l’épidémie de Covid-19 sur les patients hémodialysés et leurs soignants entre avril 2020 et avril 2022
No full textNational audienceINTRODUCTION: The health crisis linked to the COVID-19 pandemic and the changes in practices it imposed in dialysis centers were accompanied by observable psychological repercussions for both patients and caregivers. Our aim was to assess the evolution of these repercussions in these two populations, to identify the coping strategies used, and to study the association between psychological symptoms and coping strategies. METHODS: This multi-center, French, non-interventional study was conducted in two phases (T1 : April 2020 and T2 : April 2022) in 13 volunteer dialysis facilities. Pseudonymized questionnaires were used to collect sociodemographic data, self-reported psychological history, and, at both study times, stress levels (simple numerical stress scales), anxiety and depressive symptomatology (Hospital Anxiety and Depression Scale), and coping strategies (Brief COPE). Factors associated with anxiety and depression were studied with a multivariable logistic regression model. RESULTS: 177 patients and 99 caregivers participated in both phases of the study. In each population, stress and anxiety scores decreased significantly between T1 and T2 (p<0.001), while depression scores remained stable. The most frequently used coping strategy was the use of positive thoughts and was associated with lower anxiety and depression symptoms. By contrast, the avoidance strategy was associated with more anxiety-depressive symptoms. CONCLUSION: By April 2022, in France, hemodialysis caregivers’ and patients’ health crisis-related stress and anxiety levels had decreased compared with April 2020. Positive thinking coping strategies should be promoted among patients and caregivers because they have been shown to protect mood.IntroductionLa crise sanitaire liée à l’épidémie de Covid-19 et les changements de pratiques imposés dans les centres de dialyse se sont accompagnés de répercussions psychologiques aussi bien chez les patients que chez les soignants. Notre objectif était d’évaluer l’évolution de ces répercussions dans ces deux populations, d’identifier les stratégies de coping mobilisées et d’étudier le lien entre symptômes psychologiques et stratégies de coping.MéthodesCette étude multicentrique, française, non interventionnelle a été menée en deux temps (T1 : avril 2020 et T2 : avril 2022) au sein de 13 structures de dialyse. Grâce à des questionnaires pseudonymisés, nous avons comparé les niveaux de stress entre T1 et T2 (échelles numériques simples de stress), la symptomatologie anxieuse et dépressive (Hospital Anxiety and Depression Scale) et les stratégies de coping (BRIEF-COPE). Les facteurs associés aux symptômes anxiodépressifs ont été étudiés grâce à un modèle de régression logistique multiple.Résultats177 patients et 99 soignants ont participé aux deux temps de l’étude. Dans chaque population, les scores de stress et d’anxiété ont significativement diminué entre T1 et T2 (p < 0,01) alors que les scores de dépression sont restés stables. La stratégie de coping la plus utilisée était le recours aux pensées positives et était associée à des symptômes d’anxiété et de dépression moins importants. Au contraire, la stratégie d’évitement était associée à davantage de symptômes anxiodépressifs.ConclusionEn avril 2022, en France, les niveaux de stress et d’anxiété des soignants et patients en hémodialyse liés à la crise sanitaire avaient diminué par rapport à avril 2020. Les stratégies d’adaptation fondées sur des pensées positives sont à encourager chez les patients et soignants, car elles s’avèrent protectrices sur l’humeur
HF Propagation Over Curved Sea-Land-Sea Mixed Paths: Coherent Attenuation Function
No full textInternational audienceIn this communication, the coherent field propagating over a curved rough sea surface in presence of an island is computed from two approaches. First, an analytical closed-form model (residues series), based on Bremmer's and Feinberg's works, is derived by including the sea surface roughness from a heuristic way, based on Barrick's work. Second, this model is validated from the full-wave method of moments hybridized to numerical accelerations
Taking fear back into the marginal value theorem: the rMVT and optimal boldness
No full textInternational audienceForagers exploiting heterogeneous habitats make strategic movement decisions to maximize fitness. Charnov's marginal value theorem (MVT) models the sequential visit of habitat patches and their distribution to predict the optimal time allocation strategy. However, it notoriously ignores the effects of predation risk. Brown's giving-up density (GUD) theory is an alternative that includes predation risk. However, it is more abstract and does not have the specificity or graphical appeal of the MVT. Here, we formally introduce the rMVT (r stands for risk), a generalization of the MVT that incorporates predation risks. The rMVT retains the structure and graphical simplicity of the MVT, but implies a shift from residence time to expected dose of risk (micromorts) as the domain over which rate maximization occurs. We show that the rMVT can handle most types of risk, whereas the GUD theory is valid only for specific forms of risk. Applications of the rMVT show that different types of risk can yield opposite responses of optimal strategies to an increase in the risk level, and predict differential behavioral responses observed in experimental vs. natural conditions. The rMVT also predicts the optimal level of risk-taking, or "optimal boldness," and suggests that individuals should generally be bolder in riskier habitats
Implicit Shape-Prior for Few-Shot Assisted 3D Segmentation
No full textThe objective of this paper is to significantly reduce the manual workload required from medical professionals in complex 3D segmentation tasks that cannot be yet fully automated. For instance, in radiotherapy planning, organs at risk must be accurately identified in computed tomography (CT) or magnetic resonance imaging (MRI) scans to ensure they are spared from harmful radiation. Similarly, diagnosing age-related degenerative diseases such as sarcopenia, which involve progressive muscle volume loss and strength, is commonly based on muscular mass measurements often obtained from manual segmentation of medical volumes. To alleviate the manual-segmentation burden, this paper introduces an implicit shape prior to segment volumes from sparse slice manual annotations generalized to the multi-organ case, along with a simple framework for automatically selecting the most informative slices to guide and minimize the next interactions. The experimental validation shows the method's effectiveness on two medical use cases: assisted segmentation in the context of at risks organs for brain cancer patients, and acceleration of the creation of a new database with unseen muscle shapes for patients with sarcopenia
Resolving structural variations missed by short-read sequencing uncovers their pathogenicity
No full textInternational audienceBackground: Short-read genome sequencing (sr-GS) affords efficient and accurate characterisation of apparently balanced chromosomal rearrangement (ABCR) breakpoints except in 9%-11% of cases that remain undetectable.Methods: Among 117 ABCR that we studied in patients with abnormal phenotype, 14 (11.9%) could not be detected by our current strategy including sr-GS, alignment against the GRCh38 reference genome and structural variant (SV) detection using Breakdancer V.1.4.5. These were all reciprocal translocations, 10 of which implicated constitutive heterochromatin, acrocentric short arms or pericentromeric regions. We re-aligned the sequencing data against the T2T-CHM13 V.2.0 reference genome and re-analysed them using five other SV callers (DELLY, GRIDSS, LUMPY, Manta and SvABA). In addition, 11 ABCRs were further characterised using FISH, linked-read sequencing, long-read sequencing or optical genome mapping, either isolated or combined.Results: We were able to characterise the breakpoints at the bp level for 12 translocations and identify specific breakpoint patterns using Integrative Genome Viewer (IGV). In each translocation, at least one breakpoint involved highly repetitive elements such as alpha-satellites, segmental duplications, satellite repeats or other poorly mapped regions. For six out of 12 patients, one of the breakpoints could explain the phenotype either by gene disruption (CAMTA1, DYRK1A, NLGN4X) or position effect (BMP2, DIAPH2, SIX3).Conclusion: Failure of sr-GS is due to highly repetitive genomic regions at SV breakpoints, either absent from the reference genome or not attributed to a unique position. The resolution of ABCRs is essential to patients' care since it allowed us to conclude to a pathogenic variant in 50% of patients
Understanding the impact of M-OH activation on oxygen evolution in Hofmann-type 2D coordination polymers: Insights from experiments and theory
No full textInternational audienceThe oxygen evolution reaction (OER) is crucial in water electrolyzers and metal-air batteries, but its slow kinetics demand efficient electrocatalysts. 2D coordination polymers offer structural and electronic advantages, making them strong candidates. In this study, we systematically investigate the OER activity of four 2D dicyanidometallate-based Hofmann-type coordination polymers (HCPs), {M(4acpy)(2)[Ag(CN)(2)](2)}(n) (M = Mn, Fe, Co, and Ni; 4acpy = 4-acetylpyridine), denoted as M-Ag. The M-transition metals were strategically selected based on their periodic electronegativity and 3d electronic configuration to explore structure-activity relationships. Our findings reveal a periodic trend in catalytic activity: Ni-Ag > Co-Ag > Fe-Ag > Mn-Ag, with Ni-Ag demonstrating superior activity, surpassing the benchmark RuO2 by 89 mV at 100 mA cm(-2). The superior activity of the Ni-Ag is attributed to a partial surface structural reconstruction induced by the alkaline electrolyte and the applied anodic potential. Experimental results, supported by DFT calculations, indicate an adsorption-driven OER mechanism initiated by the formation of surface Ni-hydroxide species with optimized adsorption energy, which enhances catalytic activity. Under applied potential, these species convert into Ni(III)-OH, whose high acidity facilitates the proton-coupled electron transfer process, accelerating the reaction kinetics. As a pioneering study, this work demonstrates, for the first time, the tunability of M-Ag HCPs, enabling fine control over their OER catalytic performance. Moreover, it introduces the DFT-derived coordination-induced bond weakening (CIBW) effect as a new descriptor for O-H activation, providing new insights into electrocatalyst design. These findings pave the way for the rational development of 2D M-Ag coordination polymers as next-generation OER catalysts for operando applications
Synthesis and biological studies on ovarian cancer cells of new heterocyclic molecules inspired by MIM1, an inhibitor of the anti-apoptotic protein Mcl-1
No full textInternational audienceResearch on new and potent inhibitors of anti-apoptotic proteins is a very active and promising topic in bioorganic and medicinal chemistry. MIM1 is a small molecule that was among the first reported inhibitors of the anti-apoptotic protein Mcl-1. We recently corrected its structure and developed a focused library of analogues to obtain new dual Bcl-xL/Mcl-1 inhibitors as well as selective Mcl-1 inhibitors. All the corresponding molecules contained a triphenol core, established by molecular modelling as the key component to anchor these products to the binding site of these proteins. Thus, as a next step, we designed and synthesized novel analogues in which this labile core was replaced by a meta carboxylic acid. A focused library of such molecules was submitted to a set of in cellulo biological studies, which allowed new potent and selective inhibitors of Mcl-1 to be identified. Preliminary structure-activity relationships were elucidated, and molecular modelling studies allowed us to propose a rationale for the biological activity of this series of new inhibitors, in particular for the inhibition of the anti-apoptotic protein Mcl-1
Role of Hydrology, Aquatic Vegetation, Habitat Size and Connectivity in Shaping Food Webs in a Eutrophic Agricultural Marshland
No full textInternational audienceAim: Understanding food‐web responses to environmental gradients is crucial for guiding effective ecosystem management measures. This aspect remains understudied in wetlands, particularly in human‐managed marshlands, despite the fact that many environmental factors can be controlled. This study examines whether and how hydrology, aquatic vegetation, habitat size and connectivity shape food‐web structures in drainage ditches and their conservation implications.Location: Marais Poitevin, the second‐largest agricultural marshland in western France (with concepts and methodologies applicable globally).Methods: From 2015 to 2021, macrofauna (including amphibians, fish and macroinvertebrates) were sampled from 55 ditches across eleven hydrological blocks with distinct water management strategies. Using literature‐based trophic links, we reconstructed food webs (representing potential trophic interactions among locally co‐occurring taxa) and computed four descriptors: proportions of top predators and omnivores, connectance and the maximum trophic level. Then, we applied structural equation modelling to investigate the direct and indirect effects of environmental factors on these food‐web metrics.Results: Ditches with unstable hydrology, experiencing large water level fluctuations and prolonged droughts, supported food webs with higher connectance, while the maximum trophic level remained unaffected. In contrast, wider ditches with higher water levels and complex aquatic vegetation supported food webs with longer food chains but lower connectance. Many of these effects were mediated by the proportions of top predators and omnivores, and, in fluctuating hydrological conditions, by aquatic vegetation complexity.Main Conclusions: Our findings highlight the importance of maintaining key environmental conditions to support complex and diverse food webs in human‐modified ecosystems, such as in highly water‐regulated agricultural marshes. Ecosystems with food webs featuring longer trophic chains and lower connectance may be more vulnerable, as species loss can trigger cascading effects. Specifically, to sustain ecosystem integrity, conservation efforts should focus on preventing habitat contraction and simplification while mitigating hydrological fluctuations to balance food‐web stability and biodiversity
Ps-ViT: phase space vision transformer pre-training for the depth estimation in computer-generated holograms
No full textInternational audienceRecent advances in neural network pre-training have significantly improved state-of-the-art performance across various computer vision tasks, especially in scenarios with limited labeled data. These improvements stem from the ability to learn transferable and robust image feature descriptors from large-scale, unlabeled, and often noisy datasets through self-supervised training. Despite these successes, the field of holography has seen limited benefits from such approaches due to the challenges in developing effective pre-training strategies tailored to holographic data. In this work, we address this gap by introducing a pre-training method leveraging the hologram phase space representation. This approach enables the learning of efficient feature descriptors optimized for dense depth map estimation, unlocking new potential in holographic imaging applications. (c) 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved
Indirect excitons and many-body interactions in InGaAs double quantum wells
No full textInternational audienceSpatially indirect excitons in semiconductor quantum wells are relevant to basic research and device applications because they exhibit enhanced tunability, delocalized wave functions, and potentially longer lifetimes relative to direct excitons. Here we investigate the properties of indirect excitons and their coupling interactions with direct excitons in asymmetric InGaAs double quantum wells using optical multidimensional coherent spectroscopy and photoluminescence excitation spectroscopy. Analyses of the spectra confirm a strong influence of many-body effects and reveal that excited-state zero-quantum coherences between direct and indirect excitons in the quantum wells dephase faster than the much-higher-energy single-quantum coherences between excitonic excited states and ground states. The results also suggest an important energy-dependent role of continuum states in mediating system dynamics, and they indicate that dephasing mechanisms are associated with uncorrelated or anticorrelated energy-level fluctuations