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Clinically‐Relevant Static Magnetic Field Induces Release of Encapsulated Molecules from Magnetoliposomes
No full textInternational audienceMagnetoliposomes (MLs) are known for their great potential in drug release under an alternating current (AC) magnetic field (MF). However, AC magnetic fields require specific setups that remain poorly implemented worldwide, contrary to direct currents (DC) that are present in widely used magnetic resonance imaging (MRI) devices. In this work, we evidence the feasibility of a drug release triggered by a 1.5 T constant MF, currently used in clinics. The structuration of magnetite nanoparticles (NPs) stabilized by surface adsorption of citric acid (Fe 3 O 4 :CA NPs), and an optional chitosan shell (Fe 3 O 4 :CA:CS NPs) to enhance cytocompatibility, was followed under a 1.5 T constant by small‐angle X‐ray scattering (SAXS), and dynamic light scattering (DLS). MLs encapsulating both Fe 3 O 4 :CA NPs and fluorescent carboxyfluorescein (CF), were also submitted to 1.5 T, and the CF fractional release was monitored. The effect of Fe 3 O 4 :CA:CS NPs addition externally to MLs in the suspension was investigated. Results evidenced that both Fe 3 O 4 :CA and Fe 3 O 4 :CA:CS NPs formed necklace‐like aggregates under DC MF. Fluorescence experiments demonstrated a significant CF release from MLs, which was enhanced by the addition of external NPs, while empty liposomes exhibited negligible releases. Finally, a biological evaluation of MLs and NPs revealed an excellent cytocompatibility
Reconstruction dentaire 3D haute fidélité par fusion de scans intra-oraux et de données CBCT via des représentations implicites profondes
No full textInternational audienceHigh-fidelity 3D tooth models are essential for digital dentistry, but must capture both the detailed crown and the complete root. Clinical imaging modalities are limited: Cone-Beam Computed Tomography (CBCT) captures the root but has a noisy, low-resolution crown, while Intraoral Scanners (IOS) provide a high-fidelity crown but no root information. A naive fusion of these sources results in unnatural seams and artifacts. We propose a novel, fully-automated pipeline that fuses CBCT and IOS data using a deep implicit representation. Our method first segments and robustly registers the tooth instances, then creates a hybrid proxy mesh combining the IOS crown and the CBCT root. The core of our approach is to use this noisy proxy to guide a class-specific DeepSDF network. This optimization process projects the input onto a learned manifold of ideal tooth shapes, generating a seamless, watertight, and anatomically coherent model. Qualitative and quantitative evaluations show our method uniquely preserves both the high-fidelity crown from IOS and the patient-specific root morphology from CBCT, overcoming the limitations of each modality and naive stitching
Granulomatous systemic reaction mimicking sarcoidosis after hip arthroplasty: Diagnostic contribution of particle analysis
No full textInternational audienceSarcoidosis is the most frequent cause of systemic non-caseating granulomatosis in rheumatology. However, prosthesis-related granulomatous reactions induced by metallic particles can mimic sarcoidosis and should be considered in the differential diagnosis
High quality-factor terahertz phonon-polaritons in layered lead iodide
No full textInternational audienceWhile hyperbolic phonon-polaritons in van der Waals materials such as h-BN and α-MoO3 have driven major advances in mid-infrared (IR) nanophotonics, further progress at longer THz wavelengths has been hampered due to material limitations and experimental challenges. Here, we report the discovery of long-lived hyperbolic phonon-polaritons in the deep THz range in layered PbI2. Using room-temperature scattering-type scanning near-field optical microscopy, we achieved real-space imaging and broadband spectral analysis of PbI2 2D crystals transferred onto different substrates with high near-field amplitude contrast and good agreement with theoretical models. Our measurements revealed an experimental figure-of-merit related to the propagating efficiency of the polaritons above 15—on par with state-of-the-art mid-IR benchmarks—and extreme field confinement of 264 for a 144 nm-thick flake, which can exceed 300 in slightly thinner samples. These findings demonstrate that PbI2 combines strong anisotropy, low losses, and extreme mode confinement, making it a compelling candidate for deep-THz nanophotonic applications
Planar pulsating traveling wave solutions of non-cooperative Fisher--KPP systems in space-time periodic media
No full textInternational audienceNon-cooperative Fisher-KPP systems with space-time periodic coefficients are motivated for instance by models for structured populations evolving in periodic environments. This paper is concerned with entire solutions describing the invasion of open space by a persistent population at constant speed. These solutions are important in the understanding of long-time behaviors for the Cauchy problem. Adapting methods developed for scalar equations satisfying the comparison principle as well as methods developed for systems with homogeneous coefficients, we prove, in each spatial direction, the existence of a critical speed such that: there exists no almost planar generalized transition waves with a smaller speed; if the direction is rational, each rational speed not smaller than the critical speed is the speed of a planar pulsating traveling wave with time and transverse space periodicity; if the coefficients are homogeneous in space, each speed not smaller than the critical speed is the speed of a planar pulsating traveling wave with time periodicity
Integrating ethical, societal and environmental issues into algorithm design courses
No full textThis document, intended for computer science teachers, describes a case study that puts into practice a questioning of ethical, societal and environmental issues when designing or implementing a decision support system. This study is based on a very popular application, namely road navigation software that informs users of real-time traffic conditions and suggests routes between a starting point and a destination, taking these conditions into account (such as Waze). The approach proposes to intertwine technical considerations (optimal path algorithms, data needed for location, etc.) with a broader view of the ethical, environmental and societal issues raised by the tools studied. Based on the authors' experience conducting sessions with students over several years, this document discusses the context of such a study, suggests teaching resources for implementing it, describes ways to structure discussions, and shares scenarios in different teaching contexts
Generalized Non-Hermitian Hamiltonian for Guided Resonances in Photonic Crystal Slabs
No full textWe develop a generalized non-Hermitian Hamiltonian formalism for guided resonances in photonic crystal slabs, derived directly from Maxwell's equations through a systematic guided-mode expansion. By expanding the electromagnetic fields over the complete mode basis of an unpatterned slab and systematically integrating out radiative Fabry--Pérot channels, we obtain the analytical operator structure of the Hamiltonian, which treats guided-mode coupling and radiation losses on equal footing. The resulting Hamiltonian provides explicit expressions for both dispersive and radiative coupling terms in terms of modal overlap integrals and Fourier components of the permittivity modulation. For specific geometries, the Hamiltonian coefficients can be extracted from full-wave simulations enabling accurate modeling without phenomenological assumptions. As a case study, we investigate hexagonal lattices with both preserved and broken symmetry, demonstrating predictive agreement for complex band structures, near-field distributions, and far-field polarization patterns. In particular, the formalism reproduces symmetry-protected bound states in the continuum (BICs) at the point, accidental off- BICs near the point, and the emergence of chiral exceptional points (EPs). It also captures the tunable behavior of eigenmodes near the point, including Dirac-point shifts and the emergence of quasi-BICs or bandgap openings, depending on the nature of symmetry breaking. We further demonstrate in the Appendix that the same formalism extends naturally to other symmetry classes, including (1D grating) and (square lattice) photonic crystal slabs. This approach enables predictive and efficient modeling of complex photonic resonances, revealing their topological and symmetry-protected characteristics in non-Hermitian systems
Belief Propagation Decoding of Tensor-Based Modulation for Unsourced Random Access
No full textInternational audienceWe target the problem of random access over a noncoherent flat-fading single-input multiple-output (SIMO) channel with short packets. Specifically, we consider an unsourced joint coding and modulation approach based on the idea of tensorbased modulation (TBM) introduced by Decurninge et al., where the component codebooks are restricted to phase-shift keying (PSK) symbols. At the receiver, we leverage the fact that PSK symbols are on the unit circle to relax the problem to the continuous domain; we propose a low-complexity message passing belief propagation (BP) multi-user decoding algorithm, to jointly estimate the information bearing symbols and the channel coefficients. The proposed method allows efficient inter-user interference cancellation without prior knowledge of the identity of the active user nor of their channels. We establish its convergence behaviour and derive its complexity and further demonstrate the effectiveness of the algorithm for multiple antenna receiver system in comparison with meta-converse lower bound
Very High Deposition Rate Additive Manufacturing for Low Alloy Steel Parts : Ductility and Eligibility for Critical Applications
No full textInternational audienc
Gaussian Mixture Model with unknown diagonal covariances via continuous sparse regularization
No full textThis paper addresses the statistical estimation of Gaussian Mixture Models (GMMs) with unknown diagonal covariances from independent and identically distributed samples. We employ the Beurling-LASSO (BLASSO), a convex optimization framework that promotes sparsity in the space of measures, to simultaneously estimate the number of components and their parameters. Our main contribution extends the BLASSO methodology to multivariate GMMs with component-specific unknown diagonal covariance matrices. This setting is significantly more flexible than previous approaches, which required known and identical covariances. We establish non-asymptotic recovery guarantees with nearly parametric convergence rates for component means, diagonal covariances, and weights, as well as for density prediction. A key theoretical contribution is the identification of an explicit separation condition on mixture components that enables the construction of non-degenerate dual certificates—essential tools for establishing statistical guarantees for the BLASSO. Our analysis leverages the Fisher-Rao geometry of the statistical model and introduces a novel semi-distance adapted to our framework, providing new insights into the interplay between component separation, parameter space geometry, and achievable statistical recovery