Portail HAL UPEC
Not a member yet
55480 research outputs found
Sort by
Challenges in detecting volcanic forcing in climate and societal proxies: insights from the 1170/1171 CE eruption
No full textInternational audienceAbstract While our current understanding of the impacts of volcanic eruptions on the atmosphere and climate has significantly advanced, uncertainties persist regarding the climate and societal response to major volcanic events of the Common Era, especially during the high medieval period (1000–1300 CE). This study focuses on a sparsely documented medieval eruption from the late 12th century, considered, on the basis of ice-core evidence, to be one of the most prominent volcanic events of the past millennium. In this context, we explore the challenges researchers may encounter when differentiating between volcanic forcing and internal climate variability in climate and societal proxies. We highlight the importance of accurately dating volcanic eruptions for attribution studies and emphasize the need for a thorough examination of historical sources, along with a deep understanding of prevailing socio-economic and political contexts, when seeking to associate famines, pestilence, or social unrest to the climatic effects of explosive volcanism
A Matrix Therapy to counteract the early radiation-induced brain injury in rats
No full textInternational audienc
Synthesis of Laves phase hydrides YFe2H6 and YFe2H7 at high pressure: Reaching a limit of interstitial hydrogen uptake
No full textInternational audienceThe C15 Laves phase compound YFe2 has been extensively studied for its significant hydrogen absorption in its tetrahedral interstitial sites. It can stably hold up to five hydrogen atoms per formula unit under ambient conditions. However, the maximum hydrogen capacity in such Laves phase materials remains an open question. The use of high pressure is a tool that facilitates the formation of polyhydrides with high hydrogen-to-metal ratios. By subjecting YFe2H4.2 to hydrogen pressures up to 50 GPa in a diamond anvil cell without any heating, two new interstitial compounds, YFe2H6 and YFe2H7, were synthesized. Synchrotron X-ray diffraction and ab initio calculations reveal that these new compounds have ordered hydrogen atoms occupying two types of tetrahedral interstitial sites, A2B2 and B4 (for YFe2H7), and a new triangular interstitial site AB2, in an orthorhombic structure distorted from the C15 Laves phase. The magnetic properties of YFe2Hx hydrides have to be taken into account to reproduce experimental volumes, identify stable compounds on the convex hull of the YFe2-H system, and explain deviations from Vegard’s law regarding volume expansion with hydrogen concentration. These compounds cannot be retrieved at ambient pressure upon pressure release
Evaluation of the efficacy of PREVENIR (PREVention ENvIronment Reproduction) platforms on urinary markers of chemical exposure in pregnant women: protocol for an unblinded randomised clinical trial (PREVENIR-G)
No full textInternational audienceIntroduction It has been reported that pregnant women used more cosmetics daily than non-pregnant women. Phenoxyacetic acid is the main metabolite of phenoxyethanol, the most frequent preservative in cosmetics used in Europe, previously associated with reproductive effects (longer time to conception, endocrine disruptors in newborns and poorer verbal comprehension in children). In France, specialised platforms (PREVention ENvIronment Reproduction (PREVENIR)) in university hospital maternity wards are dedicated to evaluating environmental and occupational exposures in patients with pregnancy-related pathologies and supporting targeted prevention efforts. These platforms are composed of occupational health physicians, obstetrician-gynaecologists, midwives, occupational health nurses, and occupational health and environmental engineers. To assess the efficacy of these platforms, we developed a randomised clinical trial, the protocol for which is presented in this paper. The primary objective of the PREVENIR-G Study is to compare the change in urinary phenoxyacetic acid concentrations from baseline to 3 months postintervention between an intervention group and a control group. To date, the intervention has been integrated into routine care in certain facilities; however, its efficacy remains unproven. It is therefore essential to assess the relevance of this intervention, considering both its potential benefits and any adverse effects, such as increased stress or anxiety. Methods and analysis This study is an unblinded, randomised clinical superiority trial with two parallel groups (intervention vs no intervention) in four university maternity hospitals in France. We will include 300 pregnant women (aged 18 years or older) who are under 24 weeks of gestation (150 per group) referred to the participating PREVENIR platforms for management. The intervention will consist of clinical prevention management through the PREVENIR platforms, involving a consultation with an environmental health expert for an assessment of environmental and occupational exposures. During the consultation, targeted prevention messages will be provided based on identified exposures. The no intervention comparator will be a waiting-list control group. At the inclusion visit, patients will receive urine collection vials for samples to be collected at baseline and again at 3 months. Urine samples will be collected twice in a single day, on three separate days, during the collection week at home. In the week following the urine collection period, only participants in the intervention group will engage with the PREVENIR platforms. The primary outcome will be the difference in the urinary phenoxyacetic acid concentration between baseline and 3 months postintervention, compared between the intervention and control groups. Ethics and dissemination The study has been approved by the hospital ethics committee (CCP Ouest 2, no. 2023-A00941-44). All participants will provide written informed consent. Results will be shared through presentations and publications
Senescence-associated lineage-aberrant plasticity evokes T-cell-mediated tumor control
No full textInternational audienceCellular senescence is a stress-inducible state switch relevant in aging, tumorigenesis and cancer therapy. Beyond a lasting arrest, senescent cells are characterized by profound chromatin remodeling and transcriptional reprogramming. We show here myeloid-skewed aberrant lineage plasticity and its immunological ramifications in therapy-induced senescence (TIS) of primary human and murine B-cell lymphoma. We find myeloid transcription factor (TF) networks, specifically AP-1-, C/EBPβ-and PU.1-governed transcriptional programs, enriched in TIS but not in equally chemotherapy-exposed senescenceincapable cancer cells. Dependent on these master TF, TIS lymphoma cells adopt a lineage-promiscuous state with properties of monocytic-dendritic cell (DC) differentiation. TIS lymphoma cells are preferentially lysed by T-cells in vitro, and mice harboring DC-skewed Eμ-myc lymphoma experience significantly longer tumor-free survival. Consistently, superior long-term outcome is also achieved in diffuse large B-cell lymphoma patients with high expression of a TIS-related DC signature. In essence, these data demonstrate a therapeutically exploitable, prognostically favorable immunogenic role of senescence-dependent aberrant myeloid plasticity in B-cell lymphoma.Cellular senescence reflects a unique state switch of cellular functionalities beyond an apoptosis-comparable terminal cell-cycle exit 1,2 . Most prominently, senescent cells present with a largely proinflammatory and matrix-active secretome, termed the senescenceassociated secretory phenotype (SASP) 3 , and attract immune cells that, at least in part, clear senescent cells 4-6 . Physiological roles of senescence during embryogenesis and wound healing cannot simply be explained by a lasting cell-cycle cessation 7-10 , but imply senescence-associated plasticity to promote organ development or to restore tissue integrity by replenishing parenchymal cellularity 1,11,12 . We and others previously described senescence-associated stem cell-like reprogramming as a result of instructive SASP effects on neighboring non-senescent cells, or even as an intrinsic event in epigenomically remodeled senescent cells that subsequently managed to resume proliferation as post-senescent cells 10,13-24 . More specifically, we have recently linked enhancer chromatin remodeling and transcription.</p
Co-conception d'outils numériques : illustration parmi des apprenants en situation de handicap et leurs formateurs
No full textInternational audienceThe CookiNUM project develops digital educational tools adapted for people with disabilities, in the food service sector. It includes a mobile application, a virtual reality (VR) headset, a connected camera, and a web series. Co-design is central to this process to ensure truly inclusive tools. After collecting user needs, prototypes are tested in partner training centers, allowing the tools to be adapted based on evaluation results. This document presents the importance of involving users at every stage of the design process and the methodology used to engage them.Le projet CookiNUM développe des outils pédagogiques numériques adaptés aux personnes en situation de handicap, dans le secteur de la cuisine. Il inclut une application mobile, un casque de réalité virtuelle (RV), une caméra connectée et une série web. La co-conception, est au cœur de ce processus pour garantir des outils véritablement inclusifs. Après un recueil des besoins, des prototypes sont testés dans des centres de formation partenaires, permettant d’adapter les outils en fonction des évaluations. Ce document présente l’importance d’intégrer les utilisateurs dans toutes les étapes de la conception et la méthodologie utilisée pour leur implication
Field evidence of the greatest disaster in Balinese history: The 1815 Geger Bali multi-hazard event in Buleleng
No full textInternational audienceOn November 22, 1815, a M7.3 offshore earthquake and heavy rainfall triggered a major landslide on Bali's Buyan-Bratan caldera, initiating a cascading sequence of natural processes. This event, previously unstudied in scientific literature, is analyzed here using historical records, geomorphological observations, sediment analysis, radiocarbon dating, as well as textural, mineralogical, and geochemical analyses. The ~5.5 km horseshoe-shaped crown scarp on the caldera flank confirms that a translational landslide, triggered by a rock-slope failure along the rim, displaced approximately 64 × 106 m3 of material over an area of 2.38 km2. The landslide evolved as a debris avalanche involving basaltic-andesitic rock and silty-clay soils, depositing megaclasts within 10 km of the source. Midstream, it progressively transformed into a cohesive debris flow with multi-metric boulders, driven by progressive water saturation and reduced internal friction. Hydration of the mass facilitated fluidization and the transition from avalanche to cohesive debris flow. Channel bed erosion, lateral bank failures, secondary landslides, and probably rain-triggered lahars contributed to the bulking of the debris flow, increasing both its volume and thickness. After traveling 17 km, the flow entered the sea, likely triggering a local tsunami. However, no tsunami deposits associated with the 1815 landslide have been identified in coastal records, possibly due to the tsunami's limited size and/or post-depositional sediment alteration. This geomorphological study enhances the geohistorical understanding of the 1815 Gejer Bali disaster and underscores its relevance for current risk awareness and collective memory in the landslide-prone areas of Buleleng
Methylmercury degradation by hot spring sulfur-linked microbial communities as a dominant pathway in regulating mercury speciation
No full textInternational audienceSulfidic hot springs harbor unique microbial communities and are important in mercury (Hg) species transformations, although the fine scale drivers of these processes remain poorly understood. Here we studied Hg speciation in water, biofilms, and sediment across three sampling seasons in a French sulfidic hot spring with low Hg concentrations. Microbial Hg species methylation and demethylation potentials were evaluated using incubation experiments with species-specific Hg isotope tracers. Temporal variation in inorganic Hg (iHg) and methylmercury (MeHg) concentrations in water, biofilm, and sediment was observed. The incubation of microbial communities in biofilms and sediment under dark conditions exhibited low iHg methylation potentials, whereas a significant extent of biotic MeHg demethylation to oxidized iHg was found in relation to MeHg concentrations. Results from microbial diversity (16S rDNA) and the metabolic inhibition experiments suggest an important role of sulfur-linked bacterial metabolism dynamics. Specifically, sulfate-reducers and anoxygenic phototrophs were important factors in the regulation of MeHg concentrations in our study site. Overall, the observed dominance of microbial MeHg demethylation demonstrates a strong Hg detoxification capacity in sulfidic aquatic environments
La fabrique des politiques cyclables dans la métropole parisienne : quelles trajectoires des communes dans la mise en œuvre de leur système vélo ?
No full textInternational audienceThis article analyzes the paths taken by several municipalities in the Paris metropolitan area in implementing their cycling systems. It looks back at the long-term processes of institutional recognition of active mobility as a daily mobility issue, as well as the measures taken by political, institutional and associative players. Between the gradual programming of public policies and the sudden acceleration spurred by crisis situations, such as the pop-up cycle lanes deployed during the Covid-19 pandemic, what stances have been adopted by the municipalities studied within the Paris metropolitan area and what are the main differentiating factors between them ? The analysis is based on data from the « Health and Cycling » working group as part of the « From the World Before to the World After » program (2021-2024 - CNRS). It includes 26 semistructured interviews and 23 municipal monographs. The results highlight therecent surge in cycling as a mode of transport within the broader context of pre existing pro-bike public policies. In practice, the policy response to the Covid-19 pandemic merely accelerated certain dynamics, without breaking with the previously existing frameworks for action. The notion of « path dependence » highlights institutional resistance to change, revealing the persistent influence of past choices on current policy orientations.Cet article analyse les trajectoires de plusieurs communes de la métropole parisienne dans la mise en œuvre de leur système vélo. Cette étude retrace, sur le temps long, la reconnaissance institutionnelle des mobilités actives en tant qu’enjeu de mobilité quotidienne, ainsi que la mise en œuvre d’actions portées par des acteurs politiques, institutionnels et associatifs. Entre la programmation progressive des politiques publiques et des accélérations soudaines impulsées par des contextes de crises, à l’image des coronapistes déployées lors du premier déconfinement lié à la pandémie de Covid-19, comment se positionnent les municipalités franciliennes étudiées et quels sont leurs principaux facteurs de différenciation ? L’analyse s’appuie sur les matériaux du groupe de travail « Vélo et santé » du programme « Du monde d’avant au monde d’après » (MAMA 2021-2024 - CNRS), comprenant 26 entretiens semi-directifs et 23 monographies communales. Les résultats mettent en avant une montée en puissance récente du vélo comme mode de déplacement s’inscrivant cependant dans un continuum de politiques publiques pro-vélo. En effet, si les périodes de déconfinement ont accéléré certaines dynamiques, elles ne constituent pas pour autant une rupture totale avec les cadres d’action antérieurs. La notion de « dépendance au sentier » met ici en lumière les résistances institutionnelles au changement, révélant l’influence persistante des choix passés sur les orientations politiques actuelles