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Lipo-oligo/polysaccharide biorecognition at the nano-bio interface: insights into LA27 aptamer binding to biomimetic bacterial membranes
No full textInternational audienceGram-negative bacteria feature an asymmetric outer membrane, composed of phospholipids in the inner leaflet and lipopolysaccharides (LPS) or lipooligosaccharides (LOS) in the outer leaflet, which underpins virulence and antibiotic resistance. Conventional LPS assays like the Limulus amebocyte lysate test face ethical and practical challenges, motivating the development of aptamer-based detection. Here, we probe the interaction of the LA27 DNA aptamer (Kd ≈ 46 nM) with biomimetic membranes incorporating LOS/LPS from Akkermansia muciniphila, Flavobacterium sp. Root935, and Paenalcaligenes hominis strains. Asymmetric supported lipid bilayers (SLBs) and symmetric large unilamellar vesicles (LUVs) were characterized by neutron reflectometry (NR), small-angle neutron scattering (SANS), and dynamic light scattering (DLS). NR confirmed preserved bilayer asymmetry and revealed that LA27 deeply penetrates Akkermansia LOS bilayers, evidenced by increased core hydration and structural disruption, whereas interactions with Flavobacterium LOS are moderate, and those with Paenalcaligene
Neon Isotopes in Individual Vesicles of Icelandic Basaltic Glasses: Insights into the Origin of Light Volatile Elements on Earth
No full textInternational audienceThe origin of Earth's volatile elements remains a topic of debate due to the diverse sources within the solar system. Noble gases, owing to their chemical inertness, serve as powerful tracers for investigating planetary formation and mantle evolution. Noble gas isotopic studies suggest the existence of a preserved, relatively undegassed mantle reservoir, which is tapped by deep-rooted mantle plumes, such as those beneath the Galápagos, Hawaii, and Iceland. We present the first measurements of neon isotopic ratios in individual vesicles from a subglacially erupted basalt from Iceland. This method allows for the measurement of noble gas isotopes free from atmospheric contamination. Through statistical analyses of neon isotopic ratios in individual vesicles, we derive the isotopic composition for Ne of the Iceland mantle to be 12.63 ± 0.14 for the 20Ne/22Ne ratio. This value is in excellent agreement with the Galápagos mantle source and the signature expected for implanted solar wind, and lower than that of the value expected for the dissolution of a primordial atmosphere in the magma ocean. These results suggest a dominant role for solar wind implantation in accounting for Earth's mantle neon isotopic signature, and therefore as the source of light volatile elements. However, neither the implantation nor the nebular dissolution model is entirely satisfactory to explain all observations. Both models are not necessarily mutually exclusive, and more work should be conducted to tackle this long-standing issue
Contrastive learning and physics oriented evaluation for advanced segmentation in electron tomography
No full textInternational audienceDeep learning methods are now achieving strong results for segmentation tasks, and the standard metric for evaluating methods is the Intersection over Union (IOU). However, we show in this paper that IOU is not efficient in evaluating the quality of segmentation for electron tomography (ET) images of zeolites. We perform a physics-oriented evaluation to ensure that the segmentation results yield coherent physical measures. We also formalize Mixed Supervised / Self-Supervised Contrastive Learning Segmentation (M3S-CLS), a semi-supervised approach using a contrastive learning approach that uses expert annotations to train the neural network model. A detailed comparison of this method with a standard cross-entropy-based model is provided. In addition, we publish a database of five fully segmented ET volumes along with corresponding baseline results. The code and the database is available at http://gitlab.univ-st-etienne.fr/labhc-iscv/M3S-CLS
Characterization of the submarine disposal of a Bayer effluent (Gardanne alumina plant, southern France) IV: Consequences of the change in the effluent composition following modifications in the production process from 2016 to 2024
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Les promoteurs immobiliers privés à l’épreuve de la sobriété et de la circularité dans la métropole nantaise
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Using a comprehensive donor and host dataset to decipher the heritability and genetic architecture of pearl traits in the black-lipped oyster (Pinctada margaritifera)
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Efficient time-dependant fatigue reliability assessment accounting for material variability in steel structures
No full textInternational audienceFor steel structures with highly variable number of cycles to failure and when the load history is the output of a complex stochastic process, assessing fatigue damage with time is challenging.In this article, non-linear accumulation damage model available in literature is considered. With this model, the history of loading, that is to say the order or cycles, is taken into account.Using this model to estimate probability of failure requires great computational costs. In this article, two numerical strategies to reduce these costs are proposed: by creating kriging-based meta-models and dening relevant enrichment procedures, an estimation of the instantaneous probability of failure is computed. In addition, upper and lower bounds of the probability of failure are derived and enable to assess the quality of the simulation. Numerical illustrations are given on a plate with material variability and 10 000 load cycles.</div
Language and Screen-Based Multimodal Communication
No full textCollection online "Social Sciences"The main objective of this article is to explore how language and languaging are impacted by the mediatization of digital technologies. First we point to the main characteristics of screen-based communication, that is multimodality, interactivity, mobility, relationship to time and technogenres. Then we address three current research issues: multilingualism and translations, discrimination and hate speech, and automatic processing of languages in large language models
Investigating the Effects of Augmented Reality on Message Credibility When Visualizing Environmental Impacts
No full textInternational audienceAugmented reality (AR) has increasingly been used to communicate environmental impacts, offering greater engagement than conventional displays. However, its effect on message credibility—how much people believe in the content of the communication—remains unclear. In a preregistered study, we compared the perceived credibility of environmental information presented via visualizations on an AR headset or a desktop display. We created display-specific visual encodings (3D concrete for AR, 2D bar charts for desktop) and added two control conditions to cross display and encoding. We found no difference in message credibility between AR and desktop, though concrete AR was rated most engaging. Supplementary material is available at https://osf.io/n4p5c/