Archives ouvertes de Paris-Saclay
Not a member yet
272730 research outputs found
Sort by
Structural Dynamics of Peptiplexes Formed between Cationic Cell-Penetrating Peptides and DNA: A Comparative Study on TAT-HIV and NLS-SV40T
No full textInternational audienceBiomembranes evolved to protect cells and regulate exchange, forming a powerful barrier to large, charged macromolecules such as nucleic acids. In recent years, this paradigm has been competently overturned by soft biomaterials based on cell-penetrating peptides (CPPs). Herein, we investigate and compare the structural dynamics of peptiplexes formed between DNA and two cationic CPPs, TAT-HIV and NLS-SV40T. Combining experimental approaches and molecular dynamics (MD) simulations, we examined peptiplexes across mesoscopic scales to elucidate their supramolecular assembly and correlate these features with cellular uptake. We found that peptiplexes based on TAT-HIV exhibit greater structural flexibility, adopting ordered secondary structures and self-assembling into clusters and nanofibrils. In contrast, NLS-SV40T/DNA complexes retain random coil configurations, forming globule-studded coiled nanoassemblies with internal 2D hexagonal columnar phases. Calorimetry data indicated that TAT-HIV/DNA complexation is more favorable and exothermic, whereas NLS-SV40T binding to DNA is weaker and endothermic. MD simulations supported the experiments by showing that NLS-SV40T moves across DNA strands, settling into major grooves, whereas TAT-HIV bridges major and minor grooves via persistent arginine-mediated H-bonds and stronger energetics. Cell uptake assays showed that NLS-SV40T/DNA peptiplexes are internalized comparatively more efficiently, likely due to their more compact organization and lower lytic potential. Conversely, TAT-HIV induces membrane damage, as observed by atomic force microscopy, suggesting that its stronger electrostatics and enhanced H-bonding capacity may contribute to lytic activity. The findings presented here bring mechanistic insights into the structural landscape of peptiplexes, improving the rationale that supports the design of peptide-mediated gene delivery materials
: Dialogues sur les innovations qui font l’EDI aujourd’hui
No full textInternational audienceÀ travers huit grands entretiens menés sans détour, et conduits grâce au soutien de l’Association Française des Managers de la Diversité (AFMD), cet ouvrage offre un accès privilégié à la parole de leaders engagés de l’Égalité, de la Diversité et de l’Inclusion (EDI) dans des organisations basées en France. Leurs témoignages, issus d’univers organisationnels variés, mettent en lumière des actions concrètes, des stratégies d’influence, des défis récurrents et des innovations parfois pionnières. Ensemble, ils montrent comment se construit, au quotidien, une EDI vivante, exigeante et en constante adaptation. L’ouvrage met ainsi en avant la richesse des approches, la complémentarité des leviers mobilisés et la force des alliances qui se tissent pour transformer durablement les pratiques. En faisant émerger des trajectoires, des convictions et des retours d’expérience, il constitue une ressource précieuse pour comprendre les logiques à l’œuvre, s’inspirer des initiatives existantes et renforcer l’impact des démarches EDI au sein des organisations.Coordonné par Clotilde Coron et Hugo Gaillard, cet ouvrage comprend les participations de Johanna Bagur (IKEA), Virginie Baujard (EDF), Tanguy Bizien (AFMD), Amandine Bretones (Advens), Brimbelle Grandcolas (Disneyland Paris), Thomas Greverie (FDJ UNITED), Magaly Kreide (EDF), Chérifa Messaoudi (Upcoop), Delphine Pouponneau (Orange et AFMD), Anne-Lyse Raoul (JLL), avec le soutien de l’Association Française des Managers de la Diversité (AFMD)
Guest Editorial: Special Issue on Embodied Intelligence for Wearable Robotics
No full textInternational audienceWearable robotics have attracted considerable attention due to their potential advantages in human augmentation, intelligent assistance, and enhanced user experiences. Nevertheless, the real-world deployment of wearable robotic systems remains constrained by limitations in intelligence and adaptability, especially under the inter- and intra-user variability encountered in rehabilitation and daily-life scenarios. These challenges can be addressed by integrating advanced artificial intelligence—notably embodied intelligence—to enable wearable robots to perceive, learn, decide, and act in a tightly coupled manner with the human body and environment.This Special Issue on Embodied Intelligence for Wearable Robotics brings together recent advances that span neuromorphic learning paradigms, multimodal intention understanding, ergonomics-aware interaction, and continual adaptation. Collectively, the accepted contributions highlight a core message: progress in wearable robotics increasingly depends on the codesign of sensing and perception, learning and cognition, and control and embodiment, with a strong emphasis on human-centered interaction.A key enabler for embodied intelligence in wearable systems is efficient, temporally precise computation close to the sensorimotor loop. In this context, the article [A1] surveys the emerging landscape of spiking neural networks (SNNs) for rehabilitative wearable robots. By organizing prior work from the perspectives of motion decoding, robot control, and embedded/neuromorphic implementation, the review clarifies both the promise of event-driven intelligence (e.g., low power and real-time responsiveness) and the practical gaps that must be bridged for robust deployment in human–robot interaction.Another central theme is the use of embodied perception for more natural and volitional assistance. The article [A2] advances this direction by leveraging gaze cues to guide locomotion intention recognition for knee–ankle prosthetic control. By fusing eye-gaze information with other sensor modalities, the approach aims to infer user intent earlier and more reliably, thereby improving responsiveness and user experience in complex locomotion transitions.Beyond intention understanding, wearable robotics must also account for comfort, safety, and ergonomics in close physical interaction. The article [A3] addresses this need by investigating ergonomic optimization in robot–human handover scenarios. Although object handover is often studied in collaborative robotics, this work underscores its relevance to wearable and assistive systems where physical interaction quality, user workload, and comfort can directly influence acceptance and long-term usability.Finally, long-term adaptation is indispensable for wearable robots operating across diverse users and changing conditions. The article [A4] presents an adaptive learning framework for hip joint angle prediction that incorporates continual learning. By emphasizing continual adaptation, this work contributes toward personalized wearable assistance that can remain effective despite drift in user gait patterns, device dynamics, or task context.Taken together, the articles in this Special Issue demonstrate how embodied intelligence can elevate wearable robotics from “preprogrammed assistance” toward “context-aware, user-adaptive companionship” in rehabilitation and augmentation. Looking forward, several research opportunities appear particularly promising: 1) neuromorphic and edge intelligence for low-latency, low-power wearable computation; 2) multimodal perception and intent inference that integrate gaze, vision, Electromyography (EMG), kinematics, and interaction forces; 3) ergonomics- and comfort-aware learning objectives that explicitly optimize human well-being; and 4) continual, personalized learning with safety guarantees for long-term human–robot coadaptation.We sincerely thank all authors for their outstanding contributions and all reviewers for their timely, rigorous, and constructive feedback. We also express our gratitude to the Editor-in-Chief and the editorial staff of IEEE Transactions on Cognitive and Developmental Systems for their support throughout the preparation of this Special Issue. We hope this collection will serve as a valuable reference and inspire further advances in embodied intelligence for wearable robotics
Etude du transfert potentiel de chlordécone de parcelles à parcelles par ruissellement et érosion
No full textInternational audienceMessages-clés :Déploiement de mesures de terrain multi-échelles, de la placette (~ 10 m 2 ) au bassin versant (~ 100 km 2 ), de l'événement de pluie à l'archive sédimentaire (~ 50 ans), pour analyser le transfert potentiel de chlordécone de parcelles à parcelles par ruissellement et érosion.Persistance de la chlordécone sur le profil des 21 carottes de sol avec présence systématique en surface jusqu'à 40 cm, indiquant que le ruissellement et l'érosion superficielle et en ravine peuvent disperser la chlordécone.Quantification sur le long terme (~ 50 ans) de taux d'érosion significatifs à l'échelle du bassin versant, associé à des teneurs en chlordécone non-nulles, soulignant l'existence du transfert particulaire.Modélisation distribuée du ruissellement et de l'érosion préliminaire déployée à l'échelle de la Martinique et de la Guadeloupe.La modélisation montre la probabilité de transfert potentiel de chlordécone de parcelles à parcelles par ruissellement et érosion, bien qu'une quantification relative de la dispersion par ces processus, relativement à d'autres bien documentés dans la littérature (ex. percolation profonde) n'aient pas été menée.</div
What We Can Learn From the Sensor-to-Plasma Coupling Resistance Measurements in the Earth Ionosphere
No full textInternational audienceMeasurements of electric potentials and currents in the Earth’s ionosphere are primarily influenced by the thermal plasma properties and the intensity of photoelectron emission from sunlit spacecraft surfaces. These measurements can be significantly affected by a plasma sheath that forms around the satellite to neutralize surface electric charging in contact with the ambient plasma. In the ionosphere, this sheath typically ranges from a few to several tens of centimeters in thickness and contains plasma that slightly differ from the surrounding undisturbed environment. Therefore, accurately characterizing the electrical properties of the sheath is essential for reliable data interpretation. In this study, we analyze ion plasma and electric field measurements taken at an altitude of 700 km by the Centre National d’Etudes Spatiales (CNES) detection of electro-magnetic emissions transmitted from earthquake region (DEMETER) microsatellite. The data were collected during specific orbital passes when onboard instruments operated in calibration mode. During these sequences, electric currents were intentionally injected from the electric field sensors into the surrounding plasma, enabling estimation of the sensor-to-plasma coupling resistance across the sheath. Plasma parameters obtained by fitting the resistance–current curve with a standard orbital-motion-limited (OML) model are compared with those derived from the ion instrument on the same spacecraft. The dataset confirms the consistency of plasma measurements performed by the two instruments
'Les modèles et la construction des futurs - La SNBC2 et la neutralité carbone
No full textInternational audienceL'objectif sous-jacent à la notion de futur « zéro émission nette en 2050 » (NZ2050) est d'atteindre, d'ici le milieu du siècle, un équilibre entre les émissions anthropiques de gaz à effet de serre par sources et leur absorption par les puits de carbone. Cet article explore la relation entre la modélisation numérique et la prise de décision politique dans la construction d'un avenir NZ, en examinant le développement récent de la stratégie bas carbone française (SNBC-2) (2016-2018) et les processus connexes. La SNBC-2 a été la première tentative de traduire numériquement un objectif NZ2050 pour la France et une trajectoire à suivre pour y parvenir. Nous montrons qu'outre le fait d'avoir permis de quantifier plus loin dans le futur, l'une des principales leçons tirées de ce processus est que les modèles disponibles à cette fin étaient d'une pertinence limitée. L'analyse examine ces lacunes et leurs implications en ce qui concerne la performativité des modèles numériques pour faire de la NZ2050 un horizon réalisable. En nous appuyant sur la notion de « qualculation » qui considère le calcul comme un processus qualitatif et quantitatif, relationnel et algorithmique, nous soulignons le rôle crucial, mais ambigu en terme de performativité, des ajustements non calculatoires utilisés pour compenser les limites calculatoires des modèles dans le processus SNBC2.Le cas de la SNBC2 montre aussi que la relation entre les modèles et les normes politiques est plus réciproque que ce qui a été avancé dans la littérature : les modèles encapsulent certes une forme de politique qu'ils mettent en œuvre, mais ils peuvent également être remis en question et remodelés par l'émergence de nouveaux objectifs politiques
Green's Function Formalism for Impurity-Induced Resonances in Sub-barrier Proton-Nucleus Scattering
No full textInternational audienceMotivated by recent experimental refinements of stellar reaction rates, we establish a non-perturbative Green's function formalism based on the exact solution of the Dyson equation for sub-barrier proton-nucleus resonant scattering. By utilizing bare Green's functions to map the quantum tunneling problem onto a scattering formalism, we demonstrate that the summation of infinite quantum paths recovers the exact tunneling coefficients, enabling an analytical solution of the Dyson equation where the strong nuclear force is modeled as a surface delta-shell impurity embedded within the Coulomb field. Applying this framework to the astrophysically relevant , , and systems, we achieve precise agreement with experimental resonance energies while revealing a fundamental physical distinction in resonance formation. The heavier system is identified as a saturated state, residing on a geometric plateau where the resonance energy becomes insensitive to the interaction strength; our calculated value of ~MeV aligns remarkably well with the experimental level of ~MeV. In contrast, the lighter and systems emerge as threshold states in a weak-coupling window, where the resonance energy is highly sensitive to the potential parameters and is sustained near the continuum edge. In this regime, our model yields energies of ~MeV and ~MeV, closely reproducing the experimental benchmarks of ~MeV and ~MeV, respectively. We demonstrate that these threshold states are characterized by a significant enhancement of the resonant cross-section, driven by the inverse relationship between the tunneling width and the spectral density peak
Ring oscillator performance of the ATLAS inner tracker pixel readout chip
No full textInternational audienceThis paper presents experimental and simulation data to characterize the Ring Oscillators (RO) produced in 65-nm CMOS technology for the next promising generation of readout chips for the pixel detector in the Inner Tracker (ITk) at the ATLAS experiment at CERN. To enable a better understanding of the RO block embedded in ITkPixV1.1 single chip card (SCC), tests at various temperatures, voltages, accumulated total ionizing dose (TID) with X-ray irradiation, and high-temperature annealing will be presented. The objective of this study is to examine the RO output dependency based on different variable conditions and provide simulation data using Cadence, an electronic design automation (EDA) software to validate the experimental outcomes
A Chase-based Approach to Consistent Answers of Analytic Queries in Star Schemas
No full textWe present an approach to computing consistent answers to queries possibly involving an aggregation operator in databases operating under a star schema and possibly containing missing values and inconsistent data. Our approach is based on earlier work concerning consistent query answering for standard queries (with no aggregate operator) in multi-table databases. In that work, we presented polynomial algorithms for computing either the exact consistent answer to a query or bounds of the exact answer, depending on whether the query involves a selection condition or not.In the present work, we consider databases operating under a star schema. Calling data warehouses such databases, we extend our previous work to queries involving aggregate operators, called analytic queries. In this context, we propose specific algorithms for computing exact consistent answers to queries, whether analytic or not, provided that the selection condition in the query satisfies the property of independency (i.e., the condition can be expressed as a conjunction of conditions each involving a single attribute). We show that the overall time complexity of these specific algorithms is in O(W.log(W)), where W is the size of the data warehouse. Moreover, the case of analytic queries involving a having clause associated with a group-by clause is discussed in the context of our approach