Portail HAL-PSL
Not a member yet
293219 research outputs found
Sort by
The food grade bacterium Lactobacillus helveticus VEL12193 promotes autophagy by releasing membrane vesicles
No full textInternational audienceBACKGROUND: Autophagy-related processes are crucial for maintaining cellular homeostasis in eukaryotic organisms. While alterations of these processes have been strongly linked to specific human disorders, including inflammatory bowel disease, neurodegenerative diseases, and metabolic syndromes, long-term autophagy stimulation appears to be safe and to extend lifespan in model organisms. Several studies indicate that gut microbiota or derived metabolites can modulate host autophagy at the gut mucosa level but also in peripheral organs. Here, we investigated in vitro and in vivo the potential of bacterial species commonly used in food fermentation (ferments) or for their health benefits (probiotics) to modulate host autophagy. METHODS: We screened 11 bacterial strains (lactobacilli and bifidobacteria) in vitro for autophagy induction in human epithelial cells. The most effective strain identified in vitro was then tested in vivo through long-term dietary supplementation in mice to confirm its pro-autophagic effects in the gut and a distant organ, the retina. RESULTS: In vitro screening of the 11 bacterial strains revealed a strain-dependent ability of bacteria to stimulate autophagy in human epithelial cells. The Lactobacillus helveticus strain VEL12193, isolated from cheese, emerged as the strongest autophagy inducer. Long-term dietary supplementation of mice with L. helveticus VEL12193 confirmed the pro-autophagic potential of this strain, as evidenced by autophagy stimulation in the gut mucosa but also at distance, in the retina. Finally, we identified membrane vesicles (MVs) from L. helveticus as a component involved in bacteria-induced autophagy in epithelial and immune cells, with lactate and specific lipid species potentially contributing to this effect. CONCLUSION: In this study, we present evidence that intervention with ferments/probiotics stimulates autophagy in multiple cell types and organs, and we show in vitro that MVs mediate this effect. Additionally, we identify L. helveticus VEL12193 as a promising candidate for the development of healthy-aging strategies
CeTi@C80: A tender single molecule magnet with electric and magnetic didipoles investigated with magnetometry and x-ray absorption spectroscopy
No full textInternational audienc
Evaluating AI for Palm Tree Disease Detection: A Comparative Study of YOLOv8 Object Detection and U-Net Segmentation Using UAV Imagery
No full textInternational audienceAbstract. Agriculture is a cornerstone of economic stability and food security, particularly in regions like Morocco, where palm trees are vital to the environment and local livelihoods. The Figuig oasis, known for its extensive palm plantations, faces significant threats from the spread of palm tree diseases, which can lead to substantial agricultural losses. Early and accurate disease detection is critical to mitigating these impacts. This study evaluates the effectiveness of deep learning models YOLOv8 for object detection and U-Net for segmentation in detecting and segmenting healthy and diseased palm trees using Unmanned Aerial Vehicle (UAV) imagery. A dataset of 400 UAV images was annotated and divided into training (70%), validation (20%), and test (10%) sets. YOLOv8 achieved an accuracy of 78.48%, with a precision of 58.38% and a recall of 47.70%, demonstrating robust object detection capabilities but highlighting the need for improved recall to reduce false negatives. On the other hand, U-Net excelled in segmentation, achieving an overall precision of 0.8746, recall of 0.8713, and F1-score of 0.8727, with powerful performance in delineating diseased regions. The results underscore the complementary strengths of YOLOv8 and U-Net, with YOLOv8 offering efficient detection and U-Net providing detailed segmentation for precise health assessment. This study highlights the potential of integrating UAV imagery and deep learning for automated palm tree health monitoring, paving the way for early disease detection and sustainable agricultural practices. Future work will focus on optimizing model performance, expanding the dataset, and exploring advanced architectures to further enhance accuracy and recall
Regulation of cell dynamics by rapid integrin transport through the biosynthetic pathway
No full textInternational audienceConstitutive integrin endocytosis and recycling control cell movement and morphology. In contrast, the role of newly synthesized integrins delivered via the biosynthetic pathway has been largely overlooked. We used the retention using selective hooks system to monitor the localization of new integrins exiting the endoplasmic reticulum in space and time. We discovered that new integrin delivery to the plasma membrane is polarized and enhances cell protrusion and focal adhesion growth in an extracellular matrix-ligand–dependent manner. Motor-clutch modeling explained the increased adhesion as higher integrin availability driving recruitment of additional receptors. Unexpectedly, live-cell imaging revealed a small subset of fast-emerging integrin vesicles rapidly transported to the cell surface to facilitate localized spreading. This unconventional secretion depended on cell adhesion and correlated with increased surface levels of immature, high-mannose glycosylated integrin, indicating bypass of the canonical Golgi-dependent secretory pathway. Thus, spatial plasma membrane-targeting of new integrins rapidly alters adhesion receptor availability, providing cells with added plasticity to respond to their environment
All-sky search for long-duration gravitational-wave transients in the first part of the fourth LIGO-Virgo-KAGRA Observing run
No full textInternational audienceWe present an all-sky search for long-duration gravitational waves (GWs) from the first part of the LIGO-Virgo-KAGRA fourth observing run (O4), called O4a and comprising data taken between 24 May 2023 and 16 January 2024. The GW signals targeted by this search are the so-called "long-duration" (> 1 s) transients expected from a variety of astrophysical processes, including non-axisymmetric deformations in magnetars or eccentric binary coalescences. We make minimal assumptions on the emitted GW waveforms in terms of morphologies and durations. Overall, our search targets signals with durations ~1-1000 s and frequency content in the range 16-2048 Hz. In the absence of significant detections, we report the sensitivity limits of our search in terms of root-sum-square signal amplitude (hrss) of reference waveforms. These limits improve upon the results from the third LIGO-Virgo-KAGRA observing run (O3) by about 30% on average. Moreover, this analysis demonstrates substantial progress in our ability to search for long-duration GW signals owing to enhancements in pipeline detection efficiencies. As detector sensitivities continue to advance and observational runs grow longer, unmodeled long-duration searches will increasingly be able to explore a range of compelling astrophysical scenarios involving neutron stars and black holes
Beja-English-French dictionary (Sudan) with a grammatical sketch
No full textInternational audienceThe dictionary is trilingual Beja-English-French, with an English-Beja reversal index and a French-Beja reversal index, an index of proper nouns, limited to those occurring in our data, in particular nicknames based on negative clauses, and an index of clitics and affixes. It is the first one based on the southern and central varieties. The Beja-English-French part contains over 8,000 entries and sub-entries, making it the largest dictionary of this language. As much as possible examples and idiomatic expressions are extracted from natural data recorded in Sudan by the first author. Grammatical information on the syntactic use and semantic restrictions are provided wherever relevant, as well as parts of speech, definite and indefinite forms of nouns and adjectives when unpredictable, plural forms of nouns and adjectives, singulatives, the source of loan words or etymological remarks, sociolinguistic information (e.g. dialect, female register), encyclopedic information, ethnographic remarks, scientific names of plants when possible, synonyms and antonyms.The grammatical sketch builds on Vanhove (2014a) and Vanhove (2017a) and provides many new findings, analyses and insights into the grammar of Beja for all linguistic levels: phonology, morphology, syntax and information structure
Crowdsourced biodiversity monitoring fills gaps in global plant trait mapping
No full textInternational audiencePlant functional traits are fundamental to ecosystem dynamics and Earth system processes, but their global characterization is limited by available field surveys and trait measurements. Recent expansions in biodiversity data aggregation—including vegetation surveys, citizen science observations, and trait measurements—offer new opportunities to overcome these constraints. Here we demonstrate that combining these diverse data sources with high-resolution Earth observation data enables accurate modeling of key plant traits at up to 1 km 2 resolution. Our approach achieves correlations up to 0.63 (15 of 31 traits exceeding 0.50) and improved spatial transferability, effectively bridging gaps in under-sampled regions. By capturing a broad range of traits with high spatial coverage, these maps can enhance understanding of plant community properties and ecosystem functioning, while serving as tools for modeling global biogeochemical processes and informing conservation efforts. Our framework highlights the power of crowdsourced biodiversity data in addressing longstanding extrapolation challenges in global plant trait modeling, with continued advancements in data collection and remote sensing poised to further refine trait-based understanding of the biosphere
Delhi in the Shadow of Partition
No full textInternational audienceWhereas Partition Fiction has been widely examined since the 1990s in echo to the historian ‘Partition mania’, the movement naī kahānī (New Story) that emerged in the early 1950’s in the Hindi literary field has received comparatively little attention in research adopting this perspective. In fact, Partition does not represent a central position in the themes that naī kahānī developed or explored; rather, they focus on the quotidian experiences of ordinary men and women, set mostly in an urban environment (predominantly, Delhi) characterised by an oppressive atmosphere. However, Kamleshwar, a critic and novelist and a 'key' theorist of naī kahānī, has identified a clear link between the 'role of naī kahānī' and the memory of the 1947 violence and exile. The fact that Delhi, which was profoundly impacted by forced migrations, remains a prominent locale in numerous naī kahānī stories and novels, underscores a discernible correlation between the genesis of this movement and the harrowing experience of Partition. As historian Pandey writes, “the Delhi of the 1950s to the 1980s was a 'Partition' city” (1997: 2263). The present study aims to illuminate the 'shadows of Partition' in two exemplary naī kahānī fictions—one story and one novel—in which Delhi plays a pivotal role. The fate of the characters, who are not explicitly described as refugees, reflects the specific historical context of post-1947 Delhi
Frictional Contact Solving for Material Point Method
No full textMPM simulation with frictional contacts.Accurately handling contact with friction remains a core bottleneck for Material Point Method (MPM), from reliable contact point detection to enforcing frictional contact laws (non-penetration, Coulomb friction, and maximum dissipation principle). In this paper, we introduce a frictional-contact pipeline for implicit MPM that is both precise and robust. During the collision detection phase, contact points are localized with particle-centric geometric primitives; during the contact resolution phase, we cast frictional contact as a Nonlinear Complementarity Problem (NCP) over contact impulses and solve it with an Alternating Direction Method of Multipliers (ADMM) scheme. Crucially, the formulation reuses the same implicit MPM linearization, yielding efficiency and numerical stability. The method integrates seamlessly into the implicit MPM loop and is agnostic to modeling choices, including material laws, interpolation functions, and transfer schemes. We evaluate it across seven representative scenes that span elastic and elasto-plastic responses, simple and complex deformable geometries, and a wide range of contact conditions. Overall, the proposed method enables accurate contact localization, reliable frictional handling, and broad generality, making it a practical solution for MPM-based simulations in robotics and related domains
An In Situ ATR‐FTIR Electrochemical Cell for the Study of Battery Processes: Design, Implementation, and Data Analysis
No full textInternational audiencePhenomena occurring in the electrolyte as well as the interfaces with the electrodes, such as Li + solvation/desolvation and solid–electrolyte interphase formation, govern the performance and safety of Li‐ion batteries. In this article, a dedicated, spring‐loaded operando attenuated‐total‐reflectance Fourier‐transform infrared cell is presented, enabling quantitative, time‐resolved probing of the electrode–electrolyte processes under electrochemical examination. The optical design is based on a 45 ∘ incidence diamond waveguide, while the electrochemical setup comprises a gas‐tight stainless steel body. The procedure for preparing the self‐supported electrode and the acquisition protocol are also presented, together with a reproducible analysis workflow for tracking solvated versus free electrolyte solvent species without baseline subtraction. Representative measurements on composite tin electrodes validate the ability of the setup to resolve band shifts and intensity changes linked to Li + coordination and electrolyte reduction. The methodology generalizes to diverse negative‐electrode chemistries and provides molecular‐level insight into battery phenomena under electrochemical operating conditions