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Bacteria with antibacterial activities isolated from Magallana gigas microbiota as potential probiotics against Vibrio aestuarianus infections in oyster farming
No full textInternational audienceIntroduction: Oyster farming is a significant industry worldwide, but it is threatened by various diseases such as Pacific Oyster Mortality Syndrome and vibriosis. V. aestuarianus is one of the major causes of mortality for market-size oysters, resulting in significant economic losses for oyster farmers. Among the various control methods developed, probiotics appear to be a promising approach. More specifically, the use of the antibacterial activity of bacteria from the natural microbiota of the oyster Magallana gigas appears to be a sustainable solution against V. aestuarianus infections.Results: Our study investigated the probiotic potential of bacteria isolated from the microbiota of M. gigas oysters. We screened a collection of 334 bacteria against eight target pathogens, including V. aestuarianus, and identified 78 bacteria with antibacterial activity for which eight retained this activity in their culture supernatants. Five strains were selected for further testing and exposed to oysters prior to V. aestuarianus infection. Our results show that four strains significantly reduced oyster mortality, with a maximum reduction of 70 %. In addition, changes in oyster microbiota composition were observed following exposure, but the administered bacteria were not detected in the microbiota.Conclusion: Our findings demonstrate the potential of oyster microbiota-derived bacteria as probiotics for disease control in oyster farming. This approach could provide a sustainable and environmentally friendly solution for the oyster farming industry. Further research is needed to understand the underlying mechanisms and to develop effective probiotic-based strategies for preventing V. aestuarianus infection
Une exploration ethnomarketing des facteurs d’appropriation des véhicules intermédiaires : lecture à la lueur de la théorie des pratiques
No full textInternational audienc
Perspectives de l'impression 3D de méta-stents cardiovasculaires, à base de polymères et instrumentés
No full textInternational audienceAn increasing diversity of performance demands are being put on devices for medical applications. These include the need for the best mechanical, thermal, electromagnetic, chemical, and flow properties, biological compatibility, and low weight of such material systems. In this review article, we discuss three features that can confer advantages for new instrumented implementable stents. Firstly, we examine the benefits of using 3D-printed polymer stents by comparing their characteristics with metallic devices. One challenge of designing mechanical metamaterial-based stents is choosing their complex geometric structure. Secondly, we report progress in the design of printed antennas for wireless communication with implantable stents capable of monitoring real-time biological signals. This could be very important for early diagnosis of in-stent restenosis and real-time monitoring of intravascular blood conditions. Thirdly, virtual replica digital twin technology can facilitate personalized stent design based on individual patient characteristics, medical history, and real-time physiological data. This new predictive analysis in healthcare systems relies largely on the use of deep learning algorithms, appropriate for managing massive data integration. Finally, we summarize some of the major outstanding challenges that, if addressed, would move us substantially closer to realizing practically useful instrumented implantable polymer meta-stents that are integrated systems. Looking to the future, the conclusions of this review will be beneficial for researchers, clinicians, and engineers in the development and application of 3D printing for improved instrumented polymer stents
Material Parameter Identification Based on Heterogeneous Testing: Validation in case of a forming process
No full textInternational audienceThe mechanical characterization of sheet metals requires a series of quasi-homogeneous mechanical tests, requesting the use of multiple specimens to reproduce the large range of strain states characteristics of forming processes. Recent studies have shown that heterogeneous testing can provide enough data in a single test to cover a large range of strain states. The design and choice of the heterogeneous test is still a matter of investigation and validation of the model calibration in virtual forming is needed. The aim of this study is to use a mechanical model for 0.8 mm thick DP600 Dual Phase steel calibrated from heterogeneous test data as input to the numerical simulation of a forming process. The material parameters of an anisotropic plasticity model were determined with the finite element model updating method applied to two heterogeneous tests. The study explores the practical relevance of these parameters in the case of the deep drawing of a cylindrical cup. Numerical simulations of the forming process are conducted with ABAQUS software and instrumented forming experiments are carried out to validate the model calibration. The comparison between experimental and numerical data is performed using the forming load, the deformed shape and the strain field
Villages en politique. Pouvoirs et sociétés rurales en France (1634-années 1970)
No full textParmi les nombreuses métamorphoses que les campagnes françaises ont connues depuis le XVIIe siècle, la politisation est l’une des plus spectaculaires. Ce numéro spécial de Parlement[s] en prend la mesure. La plupart des pouvoirs sont appréhendés ici : celui de l’État, des seigneurs de l’Ancien Régime, des Églises, des notables et des élus des régimes autoritaires et démocratiques issus de la Révolution, des communautés rurales elles-mêmes et des nombreux acteurs, institutionnels ou informels, qui participent à la « mise en politique » des campagnes. Ce recueil rassemble une vingtaine de sources – textes et images – commentées par des historiennes et historiens spécialistes de ces questions. Comment s’organisent et évoluent, sur la longue durée et à différentes échelles, les multiples modes de domination du sol et des hommes ? Quelles sont les craintes et les attentes des villageois, leurs colères et leurs formes d’adhésion ? Comment agissent-ils, comment s’informent-ils dans des sociétés rurales qui s’alphabétisent, se médiatisent et s’intègrent au sein de l’État nation ? Telles sont les questions auxquelles ces études de cas proposent de répondre.Ce numéro s’inscrit dans le cadre des programmes d’agrégation 2025-2026 en histoire moderne et en histoire contemporaine. Ces documents et leurs commentaires seront aussi très utiles aux collègues de l’enseignement secondaire, qui pourront s’en inspirer dans le cadre de leurs cours
Biochemical Composition and Seasonal Variations of the Madagascar Algae Eucheuma denticulatum (Solieriaceae, Rhodophyta)
No full textInternational audienceAlthough the density and diversity of seaweeds in Madagascar is particularly high, these resources are underexploited and they are not part of the local population's eating habits. No study has been carried out on the nutritional properties and seasonal variation of Eucheuma species harvested in Madagascar. In this study, Eucheuma denticulatum was harvested monthly over two years (2021 and 2022) on the northeast coast of Madagascar (Sainte Marie Island). The compositional analysis revealed prominent sugars and minerals up to 41.0 and 39.5% dw, respectively. E. denticulatum showed slight variability over the seasons in the macroelements and oligoelements (Ca, K, Na, Mg, Fe, Mn) ranging from 22.8 +/- 0.2 to 25.3 +/- 0.1% dw in 2021 and 22.1 +/- 0.3 to 26.5 +/- 0.3% dw in 2022. Total amino acids varied from 2.3 +/- 0.6 to 2.5 +/- 0.6% dw during the two years. Seaweed extracts showed antioxidant activity by the in vitro method ranging from 2026 +/- 2 to 2998 +/- 4 mu g.mL-1 in 2021, and from 1904 +/- 2 to 2876 +/- 4 mu g.mL-1 in 2022. Finally, the principal component analysis (PCA) showed a correlation between protein content and environmental parameters. The nutritional characteristics therefore confirmed that E. denticulatum could potentially be used as a nutritious and functional food and could be incorporated in the diet of local populations
Shaping Waterscapes Economy: A Comparative Study of Economic Buildings of Port Cities in Gallia and Hispania (1st-5th c. AD)
No full textInternational audienc
3D printing strategies and mechanical performance assessment of continuous basalt-fibre/PA12 composites with high fibre volume fraction
No full textInternational audienceThe continuous filament fabrication (CFF), based on the fused filament fabrication (FFF), is a technology enabling to produce 3D-printed composite parts with high mechanical performance. Basalt fibres remain rather unused in CFF among fibrous reinforcements, in spite of properties similar to glass fibres. In addition, in the context of in-situ resource utilization for out-of-earth manufacturing, basalt fibres stand as an excellent earth-based analogue material of lunar regolith.This study aims at bringing deeper insights on the effect of specific printing strategies, by tuning the slicing parameters and by using a customized printer for CFF, as well as on the thermo-elastic properties of a novel high-performance composite material consisting of continuous basalt fibres embedded into a PA12 matrix, with a fibre volume fraction of 55 %.Thermal and morphological properties of the filament are first characterized. Then, the optimal slicing parameters – layer height (LH) and interfilament distance (ID) – are explored through the prism of process-induced porosity; a pore volume content as low as 2.15 % is reported for LH = 0.2 mm and ID = 1.15 mm, testifying to the high material quality and process handling. Finally, the in-plane mechanical properties of PA12-basalt are measured in the quasi-static regime, including longitudinal (0°) tension and compression, transverse (90°) tension, in-plane shear (±45°) and out-of-plane three-point bending. An extreme anisotropic behaviour is revealed. Competitive mechanical properties in the fibre direction are reported, comparable to similar glass-fibre reinforced composites. Conversely, those in the transverse direction are relatively moderate. The latter are attributed to the localized porosity induced by the juxtaposition of adjacent filaments for the interfilament distance selected
Compréhension de l'origine et prédiction des défauts de soudage laser des métaux fortement réfléchissants : étude numérique appliquée à l'alliage A2219
No full textQuelques soucis avec l'ajout des affiliations des auteurs sur la plateforme. Il y a juste deux affiliations, IREPA LASER (1) et IRDL (2). Mais les indices 1 et 2 changent quand bien meme je choisis la meme affiliation. Je pourrai corriger après...International audienceCompréhension de l'origine et prédiction des défauts de soudage laser des métaux fortement réfléchissants : étude numérique appliquée à l'alliage A221
Caractérisation de la rupture d'interfaces collées Titane/Composite sous chargement Dynamique Multiaxial
No full textInternational audienceCaractérisation de la rupture d'interfaces collées Titane/Composite sous chargement Dynamique Multiaxia