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Characterization of magnetotactic bacteria using advanced microscopic techniques (Best Oral Presentation)
No full textInternational audienceMagnetotactic bacteria (MTB) are a valuable biological model in nanobiotechnology due totheir unique native ability to form biomineralized magnetosomes (intracellular magneticnanocrystals), which offer promising applications in the biomedical field [1-3]. To understand in depth the morphology, internal structure and composition of these microorganisms, advanced microscopic characterization methods are required. In this study, several microscopy techniques used in MTB characterization were analyzed and compared, with a focus on scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM). These methods allow obtaining complementary information, from ultrastructural details (SEM & STEM) of magnetosomes to elemental chemical composition (EDX) and cell surface topography at the nanoscale (AFM). The obtained results provide a complex and accurate characterization of MTB, essential for understanding their biological functionality and for their integration into applications such as biosensors or controlled drug delivery systems. This study highlights the importance of a multidisciplinary approach in MTB analysis and contributes to the substantiation of their use as biological alternatives to synthetic nanoparticles in modern medicine
Nationwide and regional assessment of individual radiation exposure footprint
No full textInternational audienceThe management of radiation exposure (RE) is critical for protecting human health, ensuring environmental safety, and optimizing industrial and medical applications. Inadequate RE management can lead to cancer risks, genetic effects, environmental contamination, and occupational hazards. RE arises from natural, medical, and occupational sources, and assessing these factors individually fails to provide a comprehensive understanding. This study systematizes RE management by estimating RE at national and regional levels, presenting it as Radiation Exposure Footprint (REF) to identify key influencing factors. RE factors were established, exposures calculated, and summed, then divided by regional populations to derive REF. Results showed regional REF ranged from 3.8 to 7.0 mSv/year, higher than the 2–4.5 mSv/year in other countries. Medical (58 %) and indoor (27 %) sources were the primary contributors, emphasizing the need for targeted reduction efforts. The study also highlights the need for updated methodologies to assess indoor radiation, as current approaches in other countries have evolved. This comprehensive approach provides valuable insights for optimizing radiation protection and exposure management
Selective metal recovery: Innovating leaching of LFP-NMC cathode mixtures from spent lithium-ion batteries ☆
No full textInternational audienceLithium-ion batteries serve as the cornerstone of the shift towards sustainable energy and electric transportation. While the current emphasis of recycling plants is on electric vehicle batteries, there is a growing demand to expand the recycling industry to encompass smaller batteries, such as those powering electric bicycles-a sector experiencing rapid expansion. The chemical procedures essential for recycling these batteries may differ from those employed for electric vehicle batteries due to variations in material composition. In electric vehicles, the materials primarily originate from either NMC (LiNi x Mn y Co z O 2 ) or LFP (LiFePO 4 ) technologies, resulting in wellestablished compositions. Conversely, batteries from urban electric mobility comprise a blend of NMC and LFP technologies, leading to feeds with varying compositions. Therefore, the hydrometallurgical processes applied to these materials must successfully recover cobalt, nickel, manganese, and lithium, despite the presence of fluctuating and significant concentrations of iron-a common challenge in hydrometallurgy. This study will showcase how leveraging the physicochemistry of transition metals in the presence of phosphate can lead to the design of an efficient leaching process. This process selectively dissolves cobalt, nickel, manganese, and lithium from mixtures of NMC and LFP, yielding a sufficiently pure leachate.</div
Vers une meilleure prise en compte des réglementations dans la conception et la mise en œuvre de technologies: Un appui pour des communs numériques ?
No full textInternational audienceThe present paper proposes to compare the mobilisation of regulations in the management of both sociotechnical systems and the commons. To this end, a literature review combining publications on commons research and CSCW (Computer Supported Cooperative Work) will be conducted. The IAD framework (Institutional Analysis and Development framework) employed for the commons (Hess et al., 2007) will be compared with the policy knot (Jackson et al., 2014) used in CSCW (Computer Supported Cooperative Work) to highlight the parallels and disparities between the two. Finally, the study will focus on two concrete examples of the use of regulations to support digital transformation projects.Dans cette communication nous proposons une comparaison de la mobilisation des règlementations dans la gestion des systèmes sociotechniques et des communs. Pour cela nous nous appuyons sur une revue de littérature associant des publications issues de la recherche sur les communs et en CSCW (Computer Supported Cooperative Work). Nous y mettrons en évidence les similarités et différences entre le cadre IAD (Insitutional analysis and development framework) utilisé pour les communs (Hess et al., 2007) et policy knot (Jackson et al., 2014) utilisé en CSCW. Enfin nous reprenons deux exemples concrets d’utilisation des règlementations soutenant des projets de transformation numériques
Partage collaboratif de livraisons locales entre producteurs de produits alimentaires
No full textInternational audienceThis study is set within the context of local food logistics and introduces a new delivery routing problem, called Collaborative Delivery Sharing. In this problem, producers may form partnerships with other producers and are free to collaborate by organising shared deliveries to customers, including both pick-ups and drop-offs at their respective locations. The problem involves determining delivery partnerships, selecting collaboration modes (pickup and/or drop-off), and optimising the associated routing. A mathematical programming model is proposed for this problem and two metaheuristic algorithms of type Iterated Local Search and Variable neighbourhood Search. Numerical experiments demonstrate the performance of these algorithms.Cette étude s'inscrit dans le contexte de la logistique alimentaire locale et introduit un nouveau problème de routage de livraison, appelé « Collaborative Delivery Sharing ». Dans ce problème, les producteurs peuvent former des partenariats avec d'autres producteurs et sont libres de collaborer en organisant des livraisons partagées aux clients, incluant des enlèvements et des dépôts à leurs emplacements respectifs. Le problème consiste à déterminer les partenariats de livraison, à sélectionner les modes de collaboration (enlèvement et/ou dépôt) et à optimiser le routage associé. Un modèle de programmation mathématique est proposé pour ce problème, ainsi que deux algorithmes métaheuristiques de type « Recherche locale itérée » et « Recherche de voisinage variable ». Des expériences numériques démontrent les performances de ces algorithmes
Modeling the Optical Properties of Biological Structures using Symbolic Regression
No full textWe present a Machine Learning approach based on Symbolic Regression to derive, from either numerically generated or experimentally measured spectral data, closed-form expressions that model the optical properties of biological materials. To evaluate the performance of our approach, we consider three case studies with the aim of retrieving the refractive index of the materials that constitute the biological structures considered. The results obtained show that, in addition to retrieving readable and dimensionally homogeneous dispersion models, the expressions found have a physical meaning and their algebraic form is similar to that of the models used to characterize the dispersive behavior of transparent dielectrics in the visible region
Weakly-Supervised Semantic Space Structuring: Cardiac Cycle Position For Cerebral Emboli Visualization Using Contrastive Learning
No full textInternational audienceTranscranial Doppler (TCD) is an important tool for monitoring cerebral emboli, a primary cause of ischemic stroke, by detecting high-intensity transient signals (HITS). The link between HITS and their position in the cardiac cycle is emphasized in the literature, but little exploited for microemboli characterization. We therefore propose to integrate this information directly into the structure of latent spaces derived from unsupervised deep learning models toward a more interpretable data visualization. Specifically, we combine autoencoders (AEs) with a contrastive learning framework, where HITS with the same cardiac cycle position are brought closer together, while those with different positions are pushed apart. This weakly-supervised approach facilitates a guided semantic structuring of the latent space, while preserving the underlying data structure. We evaluate our method on a TCD HITS dataset and demonstrate a 11.85% improvement in the local structuring of latent spaces with respect to cardiac cycle position continuity. This trend is further validated in a more complex scenario where the latent space is structured based on both HITS type and cardiac cycle position, outperforming the AE baseline by 5.92% in terms of category continuity in the latent space. These results validate the use of cardiac cycle positioning of HITS for their characterization and demonstrate its benefits for structuring latent representations. The code is available at https://github.com/MathildeDupouy/contrastive-cardiac-cycle/
An Original Method for Detection of a Known Anomaly: Application to the Detection of Sudden Coolant Blockage
No full textInternational audienceEnsuring the safe operation of critical systems is of the highest importance, particularly when the consequences of a malfunction can be catastrophic. The present paper focuses on developing a reliable and rapid detection method for a critical event in nuclear power plants: the total and instantaneous blockage of coolant flow. Our approach involves modelling the temperature of fuel rod assemblies, taking into account past temperature readings to improve accuracy. By distinguishing between normal and abnormal temperature patterns, we can identify potential blockages early on. The proposed model and associated statistical test are versatile and can be applied to various nuclear reactors and other anomaly detection scenarios. Our results, based on real-world temperature data from the Superphénix power station, demonstrate the accuracy of the proposed model and the relevance of the detection procedure.</div
Implementing industrial and territorial ecology: The role of proximity and intermediaries in three French case studies
No full textInternational audienceThis article explores the challenges companies face when establishing cooperative relationships to implement industrial ecology initiatives. It examines the effectiveness of methodological devices in fostering inter‐firm relations and creating a favorable environment for executing industrial ecology strategies. The theoretical framework of proximities is used to analyze the nature of the connections that form between firms based on these strategies. Based on interviews and social network analysis from three case studies in France, the study concludes that geographical proximity is important for cooperative relationships, but it is not enough on its own. The activation of organized proximities requires intermediary actors and methodological devices. In addition, these collaborations need consistent and effective support to ensure their long‐term sustainability; without such support, they tend to be short lived
