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Solvothermal synthesis of hematite (α-Fe2O3) nanoparticles: Influence of surfactants on morphology, magnetic anisotropy, MRI relaxivity and biocompatibility
No full textInternational audienceRecent advancements in synthesis of hematite (α-Fe2O3) nanocrystals have enabled precise control of particle size and shape, thereby enhancing their use in catalysis, photonics, magnetic devices, electronics, medical diagnostics, magneto-mechanical actuators, solar cells and sensors. This study emphasizes the role of surfactants in the solvothermal synthesis of α-Fe2O3 nanoparticles, uncovering a novel connection between particle morphology and functional properties. By precisely adjusting surfactant concentrations (sodium hydroxide and acetic acid), the hematite particle morphology transitions from irregular shapes to uniform, plate-like structures. This transformation significantly enhances magnetic anisotropy, resulting in high coercivity (HC = 1725 Oe, above the Morin transition TM = 263 K) in the plate-like hematite nanoparticles, whereas irregularly shaped hematite nanoparticles exhibit coercivities of 235 Oe and 256 Oe (above the Morin transition TM = 251 and TM = 239 K, respectively). Furthermore, the study establishes a clear relationship between hematite nanoparticle shape and MRI relaxivity. The MRI results indicated that hematite nanoplates had superior transverse relaxivity rates (r2 = 8.68 mM−1 s−1) compared to the irregular hematite nanoparticles (r2 = 5.28 mM−1 s−1). Conversely, the irregular hematite nanoparticles displayed better longitudinal relaxivity (r1 = 0.304 mM−1 s−1) than the hematite nanoplates (r1 = 0.041 mM−1 s−1). Furthermore, the hematite nanoparticles demonstrated low cytotoxicity, indicating they are safe for cells. These findings suggest that controlling iron oxide nanoparticle morphology is crucial for enhancing their applications in magnetic materials and in biomedicine
Evaluation of phenotypic and genotypic methods for detecting KPC variants
No full textInternational audienceKlebsiella pneumoniae carbapenemases (KPCs) have spread and diversified extensively. To date, 242 clinical variants have been identified and harbor different hydrolytic capacities, thereby interfering with rapid diagnostic tests. The accurate detection of KPC variants is crucial to guide treatment and control measures in healthcare settings. We constructed KPC variants to assess the mutational impact on detection capacities of resistance-based tests. KPC variants (n = 45) were character ized phenotypically and used to measure the detection sensitivity of KPC detection methods (two lateral flow immunoassays [LFIAs], three hydrolysis tests, three selective culture media, and two PCR-based tests). We identified four antibiotic susceptibility patterns: "KPC-like" (23/45; 51%), "extended-spectrum beta-lactamase-like" (6/45; 13%), "ceftazidimase" (9/45; 20%), and outlier variants with "mixed-profiles" (5/45; 11%). These phenotypes had different impacts on the detection capabilities of hydrolysis tests (0%-100%), LFIA (44%-100%), and selective culture media (0%-100%), highlighting a risk of misdiagnosis for some KPC variants. All variants were detected with PCR-based tests. To detect the maximum of KPC variants, fecal carriage screening requires a combina tion of selective media targeting resistance to carbapenems, third-generation cephalo sporins, and ceftazidime-avibactam. From antibiotic susceptibility testing, resistance to ceftazidime ± avibactam and specific phenotypic profiles should be used as warnings to track the presence of KPC variants. We recommend LFIA as a first-line test, owing to its high sensitivity in detecting KPC variants. Nevertheless, using a combination of tests may remain wise in some situations. The spread of KPC variants remains a significant concern, particularly as reversion to ancestral phenotype could restore carbapenem resistance and lead to therapeutic failure
L'évaluation des animaux dans le discours humain : Entre stéréotypes et perception expérientielle
No full textInternational audienceThis study examines the discourse surrounding animals according to humans, focusing on the intersection of stereotypes and evaluative processes. By exploring how humans attribute traits, preferences, and emotions to animals—such as "my cat prefers warmth" or "he has a strong personality"—this research investigates the anthropocentric framing of animal behavior and experiences in language (Paveau & Ruchon 2020; Kerbrat-Orecchioni 2023).The analysis considers three interconnected aspects of "animal evaluation" defined as linguistic devices carrying stereotypes about ourselves and non-humans (Lakoff 1987; Hart & Long Jr. 2011): (1) the linguistic expression of evaluation as perceived by humans, constrained by the impossibility of accessing the animal’s own reflexive perspective; (2) evaluation as experienced by the animal, distinct from human perception; and (3) evaluative discourse, where humans articulate their interpretations of the animal's experience and their own perception of it (Cooren 2010). These layers highlight a form of transspecies anthropocentrism in discourse (Oozerally & Hookoomsing 2018), raising a main research question: how can we speak meaningfully about the lived experience of another species without imposing exclusively human frames of reference?This research draws on qualitative exploratory interviews with pet owners, focusing on domestic cats – Felis catus (Serpell, 2013) – as a case study. It critically engages with cognitive framing theories (Enfield & Levinson 2006), emphasizing the role of stereotypes in shaping how humans evaluate and discuss animal behavior. Ontological and epistemological distinctions are key to this inquiry: while ontology concerns what is, epistemology concerns what we know about the animal’s experience.To address this challenge, the study proposes integrating multiple frameworks. A “semantic of action” describes human-perceived behaviors, while a “semantic of intelligibility” (Saussez et al. 2020) seeks to interpret animal actions within their context, mediated by human understanding. Furthermore, the study advocates for interdisciplinary approaches, incorporating ethological insights, ecolinguistics (Alexander 2010; Stibbe 2018), discourse analysis (Wagener 2019) and alternative modes of representation—such as video and audio recordings—to move beyond linguistic limitations.By examining the interplay between stereotypes, evaluative discourse, and animal behavior, this research contributes to understanding the limits and possibilities of discussing non-human experiences within human-centered frameworks (Costa 2020)
Electronic Health Record based recruitment support systems: A scoping review to improve patient inclusion within clinical trials
No full textInternational audienceObjectiveElectronic Health Record (EHR) data is increasingly used to support patient recruitment in clinical trials (CTs). This scoping review focused on articles reporting an evaluation of EHR-based CT recruitment support systems (CTRSS).MethodsQuerying 3 biomedical literature databases using keywords as “clinical trial as topic”, “patient recruitment”, and “EHR” research articles describing evaluations of EHR-based CTRSS and published in English from 2013 to 2024 were included. Abstract screening was performed by 5 reviewers. Two reviewers performed full-text screening, data extraction and synthesis following 3 major themes: clinical workflow integration, technical aspects, and evaluation of EHR-based CTRSS.ResultsOf 927 screened articles, 44 qualified in scope, providing an evaluation of EHR-based CTRSS conducted within a diverse set of use cases, settings, and technologies. Results showed that 75% of the systems were CT rather than patient centric, and 20% provided patient eligibility information at clinically relevant timepoints in the patient journey and 9% sent notifications to the targeted users. EHR data was transformed according to standard models in 32% of the studies. Eligibility criteria transformation was computer assisted in 48% of the studies. The main patient-trial matching technique was querying structured data in 55% of the cases. Finally, the majority (61%) of evaluations were done retrospectively and led to a complete system evaluation from data transformation to patient – trial matching in 18%.ConclusionDespite the diversity of system scopes and designs, metrics for effective evaluation throughout the entire cycle of system implementation across user, technology, and society levels are emerging. Research effort is still needed to extend the scope, quality, and computability of both the source EHR-data and EC and to conduct harmonized evaluation of these systems to demonstrate their impact on recruitment rates, delays, and costs
A model for framed configuration spaces of points
No full text47 pages, revised and expanded version. Comments are welcomeWe study configuration spaces of framed points on compact manifolds. Such configuration spaces admit natural actions of the framed little discs operads, that play an important role in the study of embedding spaces of manifolds and in factorization homology. We construct real combinatorial models for these operadic modules, for compact smooth manifolds without boundary
Homologie des foncteurs polynomiaux stricts sur une catégorie Fp-linéaire
No full textThis preprint reworks a part of the material of our previous preprint "Functor homology over an additive category" (hal-03432824 or arXiv:2111.09719), which is being completely reorganized. 48 pages.International audienceWe generalize the strong comparison theorem of Franjou, Friedlander, Scorichenko and Suslin to the setting of Fp-linear additive categories. Our results have a strong impact in terms of explicit computations of functor homology, and they open the way to new applications to stable homology of groups or to K-theory. As an illustration, we prove comparison theorems between cohomologies of classical algebraic groups over infinite perfect fields, in the spirit of a celebrated result of Cline, Parshall, Scott et van der Kallen for finite fields.Nous généralisons le théorème de comparaison forte de Franjou, Friedlander, Scorichenko et Suslin au contexte des catégories additives Fp-linéaires. Nos résultats ont un fort impact en termes de calculs explicites d’homologie des foncteurs, et ils ouvrent la voie à de nouvelles applications en homologie stable des groupes et en K-théorie. Nous illustrons cela en démontrant des théorèmes de comparaison entre cohomologies de groupes algébriques classiques sur des corps parfaits infinis, dans l’esprit d’un célèbre théorème de Cline, Parshall, Scott et van der Kallen pour les corps finis
Les chauffeurs d’Aden. Document sur une filière migratoire de Djibouti aux États-Unis
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The geometry of covering codes in the sum-rank metric
No full textInternational audienceWe introduce the concept of a sum-rank saturating system and outline its correspondence to a covering properties of a sum-rank metric code. We consider the problem of determining the shortest sum-rank-ρ-saturating systems of a fixed dimension, which is equivalent to the covering problem in the sum-rank metric. We obtain upper and lower bounds on this quantity. We also give constructions of saturating systems arising from geometrical structures
