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Unveiling Fkbp7 as an Early Endoplasmic Reticulum Sentinel in Pancreatic Stellate Cell Activation, Collagen Remodelling and Tumor Progression
No full textInternational audienceIn pancreatic ductal adenocarcinoma (PDAC), fibroblast activation leads to excessive secretion of extracellular matrix (ECM) and soluble factors that regulate tumor progression, prompting investigation into endoplasmic reticulum (ER)-resident proteins that may support this activation. We identified FKBP7, a peptidyl-prolyl isomerase in the ER, as overexpressed in PDAC stroma compared to cancer cells, and in patients with favorable prognosis. Analysis of single-cell RNA sequencing databases revealed FKBP7 expression in pancreatic stellate cells (PSCs) and cancer-associated fibroblasts (CAFs).When analyzed by immunohistochemistry on PDAC patient tissues, FKBP7 emerged as an early activation marker in the preneoplastic stroma, preceding αSMA expression, and responding to FAKand TGFβ-induced stiffening and pro-fibrotic programs in PSC. Functional analyses revealed that FKBP7 knockdown in PSCs enhanced contractility, Rho/ FAK signaling, and secretion of pro-inflammatory cytokines as well as remodeling of type I collagen, promoting an activated phenotype and accelerating tumor growth in vivo. Conversely, FKBP7 expression supported a tumor-restraining (i.e. encapsulating) ECM characterized by type IV collagen. Mechanistically, FKBP7 interacts with BiP, and blocking this interaction instead leads to increased PSC secretion of type I collagen. Thus, FKBP7 serves as a novel PSC marker and ER regulator in a complex with BiP of the secretion of specific collagen subtypes, highlighting its potential to mediate ECM normalization and constrain PDAC tumorigenesis.</div
Towards lower annealing temperatures and enhanced functional properties in aerosol-deposited piezoelectric thick films: A study of the effect of Li additive on BaTiO3 films
No full textInternational audienceThe effect of incorporating Li additive (Li2CO3) into aerosol deposited BaTiO3 thick films was investigated. The addition of Li2CO3 to the deposited powder facilitated grain growth during post deposition process, even for low annealing temperatures (≤ 700 °C). Therefore, this additive decreased the threshold for ferro/piezoelectricity recovery from 800 °C to 650 °C. Furthermore, annealing at temperatures ≥ 800 °C yielded grain sizes ranging from 100 nm to 700 nm, unprecedented in our previous investigations. Substantially improved ferroelectric and piezoelectric responses were obtained in the 800-900 °C range, with Pr values doubling to 12 µA.cm -2 for films annealed at 900 °C. Moreover, the use of this additive improved leakage behavior, achieving a leakage current density of 0.1 µA.cm -2 and an electrical resistivity of 10 11 Ω.cm at 700 °C. Microscopic analyses revealed a carbon containing secondary phase at grain boundaries, probably corresponding to Li2CO3.</div
Éditorial. Des espaces ruraux en recomposition : inégalités et formes de régulation
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Exploiting ray tracing technology through OptiX to compute particle interactions with cutoff in a 3D environment on GPU
No full textInternational audienceComputing on graphics processing units (GPUs) has become standard in scientific computing, allowing for incredible performance gains over classical CPUs for many computational methods. As GPUs were originally designed for 3D rendering, they still have several features for that purpose that are not used in scientific computing. Among them, ray tracing is a powerful technology used to render 3D scenes. In this paper, we propose exploiting ray tracing technology to compute particle interactions with a cutoff distance in a 3D environment. We describe algorithmic tricks and geometric patterns to find the interaction lists for each particle. This approach allows us to compute interactions with quasi-linear complexity in the number of particles without building a grid of cells or an explicit kd-tree. We compare the performance of our approach with a classical approach based on a grid of cells and show that, currently, ours is slower in most cases but could pave the way for future methods
Laser powder bed fusion of diamond‐reinforced AlSi10Mg: printing process, interfacial characterization, and mechanical properties
No full textInternational audienceThe additive manufacturing of metal matrix composites (MMCs) using laser powder bed fusion (LPBF) is gaining considerable attention for its ability to produce high‐performance materials with intricate geometries. However, incorporating reinforcement such as diamond (D) particles poses challenges to the melting and solidification behavior of the powders, potentially affecting print quality. In this study, the laser irradiation of AlSi10Mg powder mixed with 5 vol% of uncoated D particles is investigated across varying processing parameters. Dense (97%) and crack‐free parts are successfully produced using high laser powers (300 and 400 W) and low laser scanning speeds (300 and 400 mm s −1 ). It is shown that the energy needed for proper melting of the powder surpasses that required for printing pure AlSi10Mg. Scanning transmission electron microscopy coupled with energy‐dispersive X‐ray spectroscopy uncovers a direct interfacial reaction between the molten aluminum (Al) and the D reinforcement, forming Al carbide at the Al–D interface. Moreover, Al composites processed under optimal energy density exhibit an enhanced Young's modulus. It is highlighted that optimizing LPBF processing parameters is crucial to achieve superior material properties in MMCs, while controlled matrix–reinforcement interactions offer the potential for tailored properties
On the Use of Needle-Like Perturbations in Spatially Heterogeneous Control Systems
No full textInternational audienceIn this paper we consider a general control system involving a spatially heterogeneous dynamics. This means that the state space is partitioned into several disjoint regions and that each region has its own (smooth) control system. As a result, the dynamics discontinuously changes whenever the trajectory crosses an interface between two regions. In that spatially heterogeneous setting (and in contrast with the usual smooth case), a needle-like perturbation of the control may generate a perturbed trajectory that does not uniformly converge towards the nominal one, and may lead to the absence of a corresponding first-order variation vector. The first contribution of this paper is to illustrate this issue by means of a simple counterexample. Our second and main contribution is to provide a modified needle-like perturbation of the control (adapted to the spatially heterogeneous setting) which generates a perturbed trajectory that uniformly converges towards the nominal one, and leads to a corresponding first-order variation vector (which has the particularity of admitting a discontinuity jump at each interface crossing). This is made possible under several assumptions (including transverse crossing conditions), by introducing new tools such as auxiliary trajectories and auxiliary controls and by using a conic version of the implicit function theorem
La conception en design à l'ère de l'IA Générative : réflexions sur le sens du partage de compétences en agence de création ?
No full textThe context of this research is the convergence of professional, academic and pedagogical experiences as a designer, a teacher and a researcher. Empirical data and theoretical knowledge were crossed to answer the following hypothesis: to preserve meaning at work, if generative AI is integrated into a creative agency, then a new identification of skills and a different sharing of them must be implemented. To conceive any kind of design, a better understanding of users' expectations and needs has not changed since the advent of management sciences and human sciences in design; but the transition to generative AI renews these approaches as much as it will shake up the creative one. This reflection on design management reveals some of the impacts of IAG for the designer, some of the modalities to be implemented in the company and the general logic for preserving meaning at work. For both the employee and the organisation, meaning at work is a key factor in the quality of working life, and thus in their respective performance. Semiotics enables the elements that contribute to the construction of meaning at work to be distributed at the right levels of relevance. Coupled with coaching, it improves the management of skills and their valorisation. These changes for companies integrating designers, will also require a change in the designer's learning path; but this part, training, is not developed here.Le contexte de cette recherche est la convergence d'expériences professionnelles, académiques et pédagogiques en tant que designer, enseignant et chercheur. Des données empiriques et des connaissances théoriques ont été combinées pour soutenir l'hypothèse suivante : pour conserver le sens au travail, si l'IA générative est intégrée à une agence de création, une nouvelle identification des compétences en création et un autre partage de celles-ci sont à mettre en oeuvre. Pour concevoir un quelconque design industriel, une meilleure compréhension des attentes et besoins des utilisateurs n'a pas changé depuis l'avènement des sciences de gestions et des sciences humaines en design ; mais le passage à l'IA générative renouvelle autant ces approches qu'il va bousculer celle créative. Cette réflexion sémiologique en management du design aborde certains impacts de l'IAG pour le designer, certaines modalités à mettre en oeuvre dans l'entreprise et la logique générale pour conserver le sens au travail. Ce dernier est un atout dans la qualité de vie au travail pour le salarié, l'organisation et dans leurs performances respectives. La sémiologie permet la distribution aux bons niveaux de pertinence des éléments participant à la construction du sens au travail. Couplée à du coaching, elle améliore la gestion des compétences et de leurs valorisations. Ces changements pour l'entreprise intégrant des designers demandent également de faire évoluer leurs parcours d'apprentissage, mais cette partie n'est pas développée ici.</div
Magnetic Resonance Spectroscopy (MRS) transforming multiple sclerosis (MS) diagnosis
No full textInternational audienceAnna is one of the 1.8 million people worldwide with multiple sclerosis who live with the uncertainty of disease progression every day. Traditional Magnetic Resonance Imaging scans every six months reveal brain lesions but can't predict how the disease will progress. A new technology, Magnetic Resonance Spectroscopy (MRS), shows promise in predicting disease progression by revealing cerebral metabolism and neurophysiological changes. However, current MRS measurement methods vary between medical centers, affecting reliability. Standardizing these measurements using Physics-Informed Neural Networks (PINNs), which are more reliable than traditional neural networks because they are based on the physics of spectra, could ensure accurate, comparable results worldwide. This would reassure doctors and patients like Anna, and potentially improve their quality of life by enabling earlier and more precise treatment
High-harmonic generation in solids from a high-energy fiber laser system
No full textInternational audienceWe demonstrate high-harmonic generation (HHG) in solids using a high-energy fiber laser system operating at 1550 nm. The driving few-cycle source consists of an erbium-doped fiber chirped pulse amplifier combined with a postcompression stage featuring a gas-filled hollow-core photonic crystal fiber (HC-PCF). The nonlinear self-compression process in the HC-PCF enables the generation of ultrashort pulses with sub-50 fs durations and µJ-levels energies at a 660 kHz repetition rate. Perturbative and non-perturbative harmonics were subsequently generated when focusing the few-cycle pulses into zinc oxide (ZnO) and magnesium oxide (MgO) bulk samples. In the latter, in particular, we observed the generation of EUV harmonics up to H29 (below 55 nm), highlighting the remarkable potential of such a platform for the development of compact HHG sources