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Phage–phage competition and biofilms affect interactions between two virulent bacteriophages and Pseudomonas aeruginosa
No full textInternational audienceVirulent bacteriophages (or phages) are viruses that specifically infect and lyse a bacterial host. When multiple phages co-infect a bacterial host, the extent of lysis and dynamics of bacteria–phage and phage–phage interactions are expected to vary. The objective of this study is to identify the factors inf luencing the interaction of two virulent phages with different Pseudomonas aeruginosa growth states (planktonic, an infected epithelial cell line, and biofilm) by measuring the bacterial time-kill and individual phage replication kinetics. A single administration of phages effectively reduced P. aeruginosa viability in planktonic conditions and infected human lung cell cultures, but phage-resistant variants subsequently emerged. In static biofilms, the phage combination displayed initial inhibition of biofilm dispersal, but sustained control was achieved only by combining phages and the meropenem antibiotic. In contrast, adherent biofilms showed tolerance to phage and/or meropenem, suggesting a spatio-temporal variation in the phage–bacterial interaction. The kinetics of adsorption of each phage to P. aeruginosa during single or co-administration were comparable. However, the phage with the shorter lysis time depleted bacterial resources early and selected a specific nucleotide polymorphism that conferred a competitive disadvantage and cross-resistance to the second phage. The extent and strength of this phage–phage competition and genetic loci conferring phage resistance are, however, P. aeruginosa genotype-dependent. Nevertheless, adding phages sequentially resulted in their unimpeded replication with no significant increase in bacterial host lysis. These results highlight the interrelatedness of phage–phage competition, phage resistance, and specific bacterial growth state (planktonic/biofilm) in shaping the interplay among P. aeruginosa and virulent phages
Some topics in random walks
No full textInternational audienceWe collect a few recent results on random walks, which are ubiquitous in probability theory. The topics covered are: persistence problems for stochastic processes, large fluctuations in multi-scale modeling for rest hematopoiesis, and fine properties of the elephant random walk
Convergence analysis of a high-order Multi-scale Finite Element Method (MsFEM) for Stokes flows in heterogeneous media
No full textAn enriched non-conforming Multi-scale Finite Element Method (MsFEM) to solve viscous incompressible flow problems in genuine heterogeneous or porous media was proposed in [Q. Feng, G. Allaire, and P. Omnes, Multiscale Model. Simul., 20(1):462-492, 2022]. The main feature of this MsFEM is the consideration of high-order sets of weighting functions: for the velocity, they are polynomials of order n on the faces and of order n-1 in the volume of the elements; for the pressure they are polynomials of order n in the element volume. In the previously cited reference, only the case n = 1 was numerically tested. The present paper proposes the first implementation for the case n = 2 in two and three dimensions. Furthermore, a discrete analysis of this MsFEM applied to the Stokes problem in heterogeneous media is performed. In particular, a first error estimate is obtained, proving the convergence of this MsFEM for the Stokes problem in periodic perforated media. In addition, it has been shown in the previously cited reference, that the continuous local problems involved in this MsFEM are well-posed. Here, their discrete counterparts are also proved to be well-posed, for any n in two dimensions and for n equal to 1 and 2 in three dimensions, with a judicious choice of non-conforming pairs of finite elements
Redesigning deep neural networks: Bridging game theory and statistical physics
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Widening exposome exploration with a novel multiplexed HRMS analytical approach : a case study on pesticide internal exposure
No full textInternational audienceIntroduction : Human exposure to food and environmental chemical contaminants including pesticides is generally assessed by indirect (e.g. questionnaires) and/or targeted methods focusing on a limited number of selected compounds. These methods often require a large amount of sample for analyses as complete and sensitive as possible. Thus, human health risks associated with multi-exposure to complex mixtures currently remain underexplored. Based on the exposomics concept and previous studies (1,2), we propose an innovative global chemical profiling approach integrating three complementary HRMS platforms (LC-HILIC-HRMS, LC-C18-HRMS and GC-HRMS), for capturing an extended range of contaminants and related metabolites from a unique urine sample.Methods : Fractionation of reduced-volume urine samples (0.5 mL) was preformed using Strata-X® SPE cartridges. HRMS experiments were conducted on GC-Orbitrap q-Exactive (GC-MS), Sciex X-500-R Q-ToF (C18-LC-MS) and LTQ-Orbitrap XL (HILIC-LC-MS) instruments. Data processing was carried out on both commercial and open source softwares (Trace Finder, W4M, Scannotation, …). A set of 187 standard compounds (parent compounds + metabolites) covering both a large range of molecular weights (72 g/mol1000) from a single sample, provides valuable data for assessing associations with health endpoints for epidemiological studies. Novelty : innovative multiplexed HRMS methodology for wide exposomics from a unique sample. References1 E. L. Jamin et al. Anal. Bioanal. Chem., 2014, 406, 1149-1161.2 N. Bonvallot et al. Sci. Tot. Environ., 2021, 786, 147499.3 T. Moufawad et al. In preparatio
The limits of decolonizing an international humanitarian organization. "Decoloniality" as a new guiding principle?
No full textInternational audienceBy 2025, the share of international staff from the Global South (and in particular Africa) within the humanitarian organization Médecins Sans Frontières (MSF) has reached nearly 50%. By changing the relationship to time, authority, abuse, management or gender, this "southernization" of staff generates tensions and internal criticism. Based on participant observation and semi-structured interviews, we question the possibility of a decolonization of aid by assessing the extent to which these new members can depart from relations of domination and/or propose their own ways of thinking and acting. As a conclusion, we suggest decoloniality as a new guiding humanitarian principle
Etude de l’alimentation totale française 3 (EAT3) - Rapport méthode
No full textCitation suggérée : Anses. (2025). Etude de l’alimentation totale française 3 (EAT3) - Rapport méthode. (saisine2019-SA-0010). Maisons-Alfort : Anses, 90 p
Titre : Une pédagogie narrative plurisémiotique co-construite : Apprendre la langue à partir des traces expressives des élèves migrants
No full textInternational audienceChercheure associée -Sorbonne Nouvelle, EXPERICE Résumé Ce texte présente une méthode développée depuis 2016 dans le cadre d'une recherche-actioncréation menée auprès d'élèves migrants en France et en Allemagne. Cette démarche, que je nomme pédagogie narrative plurisémiotique co-construite, vise à transformer les formes d'expression décalées, inachevées ou silencieuses des élèves (gestes, interlangues, erreurs, récits fragmentaires) en supports d'apprentissage langagier et de subjectivation. En articulant narration symbolique, multimodalité expressive et didactique du langage, cette méthode repose sur la co-création de récits artistiques et pédagogiques (livres, clips, cahiers) qui permettent aux élèves d'habiter la langue à partir de leurs propres ressources. Ce document en pose les fondements méthodologiques et théoriques.</div
Breaking the Strength-Ductility Paradigm in Metallic Thin Films via Atomic-Scale and Microstructural Engineering
No full textInternational audienceThe current trend toward miniaturization in devices components in key technologies such as microelectronics, energy production, sensors and wear protection requires the development of high-performance thin films (TFs) with superior mechanical properties combining mutually excluding mechanical properties such as high yield strength and ductility. Achieving such performance, relies on leveraging microstructure-induced mechanical properties, requiring the precise control of TF’s microstructure, atomic composition, grain size and thickness based on nanoengineering design concepts. Here, I will present recent results for several class of advanced TF materials including nanostructured metallic glasses (ZrCu, ZrCuAl) [1, 2] high entropy alloys (CoCuCrFeNi, AlxCoCuCrFeNi) and nanolaminates (fully amorphous, amorphous/crystalline, FCC/BCC) [3, 4], highlighting how the control of the microstructure affect the and micro-scale mechanical behavior and enable ultimate mechanical properties. Among the main results, I will show the fabrication of fully amorphous Zr24Cu76/Zr61Cu39 nanolaminates with controlled nanoscale periodicity (Λ, down to 5 nm), local chemistry and glass-glass interfaces [3]. I will show how the shear band instability can be mitigated when Λ ≤ 50 nm, reaching remarkably large elastic/plastic deformation (16%) and yield strength (~2GPa) by micro-pillar compression [3]. Then, I will present the synthesis nanostructured cluster-assembled metallic glass and High Entropy Alloy TF. I will show how nanogranular ZrCu metallic glass can reach ultimate yield strength (>3 GPa) and ductility (>6 %). Then, I will focus on the synthesis of crystal/glass ultrafine nanolaminates [4] in which ∼4 nm Al (crystalline) separate 6 and 9 nm-thick Zr50Cu50 metallic glass nanolayers, showing high yield strength (3.4 GPa) in combination with enhanced elastoplastic deformation (>6%, in compression), while managing to effectively block the percolation of shear bands even at >15% deformation [4]. Finally, I will present, the synthesis of CoCrCuFeNi High Entropy Alloys TFs with a wide range of microstructures and nanosized grains, enabling strong Hall-Petch strengthening and thermal stability.In the last part of the seminar, I will present recent developments within LSPM, highlighting new research activities dealing with the synthesis of nanostructured metallic films and the development of a new platform for in situ SEM mechanical-electrical characterization.References[1] M. Ghidelli et al., Novel class of nanostructured metallic glass films with superior and tunable mechanical properties, Acta Mater. 213 (2021) 116955.[2] C. Poltronieri et al., Mechanical properties and thermal stability of ZrCuAlx thin film metallic glasses: Experiments and first-principle calculations, Acta Mater. 258 (2023) 119226.[3] A. Brognara et al., Tailoring Mechanical Properties and Shear Band Propagation in ZrCu Metallic Glass Nanolaminates Through Chemical Heterogeneities and Interface Density, Small Struct. (2024) 2400011.[4] F. Bignoli et al., Novel class of crystal/glass ultrafine nanolaminates with large and tunable mechanical properties, ACS Appl. Mater. Inter. 16(27) (2024) 35686-35696
Soft skills in dental student curricula: an evidence and gap map
No full textInternational audienceBackground Soft skills are recognised as essential for dental practitioners, but their integration into dental education is inconsistent. The aim of this evidence and gap map was to explore the use of soft skills teaching initiatives in undergraduate dental education and to clarify the key domains in this research field. Methods An extensive search of studies from 2014 to 2024 on the PubMed database was carried out by four researchers. Inclusion criteria covered articles, including both advocacy or position papers, and studies reporting on implemented and evaluated educational interventions in soft skills in undergraduate dental education. The search is aligned with Joanna Briggs Institute and PRISMA-ScR guidelines and based on predefined coding frameworks from the literature. ResultsFrom the 1,449 records initially identified, 317 were included after rigorous examination. There were generally more educational programme description or evaluation papers compared to advocacy articles. More than two-thirds of the included articles were published in pedagogy-focused journals. The papers were classified into four domains (i.e. dentist-patient relationship, cooperation, life balance and clinical reasoning), with most studies falling into the dentist-patient relationship and cooperation domains. Various graphic formats present the results (i.e. a visual map, radar charts, and a geographical map), which provides a comprehensive and accessible representation, thus aiding in the exploration of the identified themes, connections, and key domains in this research field.Conclusions This evidence and gap map represents an attempt to capture a picture of existing educational practises relating to soft skills in dentistry teaching and, thus, raise broader questions regarding how soft skills should contribute to redefining the role of dentistry for dentists, patients and society. However, integrating soft skills comes with various challenges, such as the training of educators, the standardisation of content and evaluations, and the development of research evaluating the impacts of soft skills teaching on dentists and patients. Ultimately, it would be beneficial to engage patients in defining the various curriculum items and prioritising the most relevant ones concerning soft skills. This collaborative approach would ensure that the educational content aligns with the needs of patients and helps address larger public health challenges.</div