Portail HAL de l'Université Picardie Jules Verne
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Evolution of Focal Conic Domains in SmA-N Phase Transition
No full textInternational audienceFocal conics are nice geometric structures of liquid crystal phases which present periodicity such as smectic phase, cholesteric phase, etc. Here, we focus on focal conic domains (FCD) in smectic A liquid crystal. During a phase transition from smectic A to nematic, these FCDs evolve as the eccentricity increases until they completely disappear. Here, we present experimental observations of this phenomenon, along with a modeling approach that allows for an interestingly precise description of the phenomenon, revealing, in particular, a coefficient that seems to exhibit the behavior of a critical exponent
Development of a urinary antigen test for BK Polyomavirus to help clinicians in patients’ follow-up
No full textInternational audienceBK polyomavirus (BKPyV) is responsible for hemorrhagic cystitis and nephropathy in bone marrow- and kidney transplant recipients, respectively. Monitoring BKPyV DNAuria and/or DNAemia by quantitative molecular tests is thus a common practice in the management of these patients. However, critical issues have been raised regarding these methods and the detection of viral genomes by positive PCR is not always associated with true viral replication. Identification of novel biomarkers and development of new assays are thus needed to help clinicians in patients' follow-up and enable timely and beneficial therapeutic interventions. Here, we describe the development of a urinary lateral flow assay that specifically detects the major BKPyV VP1 protein in a few minutes. This assay was characterized using cell culture-produced virus, pseudoviruses as well as VP1 pentamers representing the four BKPyV genotypes, diluted in urine matrix. The limit of detection was around 1 µg/mL of purified VP1 pentamers. This assay also enabled to detect BKPyV VP1 in frozen urine from transplant patients with high DNAuria. Clinical validation studies are now needed to evaluate the performance of this assay in real life and its relevance for interventions
¿Requiere Drácula de una rehabilitación? La “rectificación” de un mito moderno por Rafik Schami en el contexto de la “nostalgia nazi” y el revisionismo histórico de Alemania Occidental
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Liens entre les profils motivationnels des élèves en EPS, le sexe et le niveau habituel d’activité physique
No full textInternational audienceCette étude s’inscrivant dans la théorie de l’autodétermination (Ryan et Deci, 2017) vise à la fois à cerner la motivation des élèves du secondaire à participer aux cours d’Éducation Physique et Sportive (EPS) et à identifier les rôles du sexe et du niveau habituel d’activité physique. Une analyse en cluster a permis d’identifier quatre profils motivationnels distincts auprès de 539 collégiens et lycéens : « autodéterminé », « déterminé », « modéré », « peu déterminé ». Des analyses différentielles ont mis en évidence des liens significatifs entre le profil motivationnel et le sexe et/ou le niveau habituel d’activité physique. Les filles, les élèves ne fréquentant pas l’association sportive (AS) de leur établissement, ceux ne pratiquant pas une activité physique et sportive extra-scolaire, ceux ayant un faible niveau d’activité physique sont-surreprésentées parmi le profil « peu déterminé ». Au contraire, les garçons sont surreprésentés parmi le profil « déterminé ». Par ailleurs, les élèves fréquentant l’AS ou pratiquant une activité physique et sportive extra-scolaire sont sur-représentés parmi les profils « autodéterminé » et « déterminé ». Ces résultats sont discutés avant une présentation des limites et les implications de l’étude
Insights into structural, thermal, physical, optical, and electrical properties of novel ZnO-doped lithium–titanium-phosphate glasses
No full textInternational audienceThis study investigates novel ZnO-doped lithium-titanium-phosphate glasses, synthesized via the melt-quenching method, and characterizes their physical, structural, thermal, optical, chemical, mechanical, and electrical properties, with a focus on the impact of varying ZnO content on these properties. An increase in ZnO content from 20 mol% to 27.27 mol% induces significant local structural changes, promoting enhanced network polymerization, density, and chemical durability, while concurrently reducing thermal stability and mechanical strength. EPR analysis confirmed that titanium remained in the Ti4+ state, while optical measurements revealed an increased band gap, attributed to the role of ZnO in preventing Ti4+ reduction and minimizing localized states. The electrical conductivity decreases with increasing ZnO content, with the highest value measured at 1.73 × 10−10 Ω−1 cm−1. High-ZnO glasses exhibit mainly electronic conductivity of 4.02 × 10−9 Ω−1 cm−1 at room temperature. The frequency-dependent conductivity follows Jonscher's power law, with the charge transport governed by a correlated barrier-hopping mechanism, remaining stable across temperatures and compositions
Winter fruit contribution to the performance of the invasive fruit fly Drosophila suzukii under different thermal regimes
No full textInternational audiencePolyphagous insect species develop using multiple host plants. Often considered beneficial, polyphagy can also be costly as host nutritional quality may vary. Drosophila suzukii (Matsumura) is an invasive species that can develop on numerous fruit species over the annual cycle. Here, we assessed the contribution of winter‐available fruit to the development of seasonal populations of D. suzukii , under fluctuating late winter/early spring temperature regimes. We infested an artificial diet and three suitable fruit species available in winter/early spring ( Aucuba japonica , Elaeagnus × submacrophylla , Viscum album ) with D. suzukii larvae under three temperature regimes: constant 20 °C, fluctuating controlled regime of 8–15 °C (12 h of light at 8 °C and 12 h of dark at 15 °C), and uncontrolled outdoor regime during spring. As expected, fly performance was impaired by early spring‐like environmental conditions, whatever the development diet, and the winter fruit were suboptimal diets compared to the artificial diet, whatever the thermal regime. However, under cold fluctuating temperature regimes, the ranking of fruit supporting the best performance changed, highlighting the occurrence of physiological trade‐offs. Winter‐acclimated females preferentially oviposited in A. japonica and/or E. ×submacrophylla , whatever the thermal regime, which does not support the preference–performance hypothesis. This finding is also discussed in the context of D. suzukii management strategies
Changer pour apprendre : l’état d’esprit de développement comme levier de transformation éducative
No full textInternational audienceThis theoretical summation is dedicated to a thorough examination of the growth mindset and its transformative influence in the educational field, particularly through wise interventions, with a special focus on the contribution of Anglophone literature analyzed in French. Relying on existing works, we explore how the conceptualization of intelligence as a malleable trait can reshape pedagogical practices and promote academic resilience. However, the growth mindset theory has been the subject of debate, with some researchers highlighting the heterogeneity of effects depending on context and populations. Our analysis explores these controversies while suggesting ways to adapt and refine interventions based on specific needs. A practical guide is also included to support educators in implementing programs that foster a growth mindset. In conclusion, this note emphasizes the importance of integrating these principles into the French educational system to maximize students’ learning potential.Cette synthèse théorique se consacre à l’examen approfondi de l’état d’esprit de développement et de son influence transformatrice dans le domaine éducatif, notamment via les interventions psychosociales, avec un accent particulier sur l’apport de la littérature anglophone analysée en français. En s’appuyant sur des travaux existants, nous explorons comment la conceptualisation de l’intelligence comme une capacité évolutive peut remodeler les pratiques pédagogiques et promouvoir la résilience académique. Toutefois, la théorie de l’état d’esprit de développement fait l’objet de débats, certains chercheurs soulignant l’hétérogénéité des effets selon les contextes et les populations. Notre analyse examine ces controverses tout en proposant des pistes pour adapter et affiner les interventions en fonction des besoins spécifiques. Un guide pratique est également inclus pour soutenir les enseignant·es dans la mise en place de programmes favorisant un état d’esprit de développement. En conclusion, cette note souligne la pertinence d’intégrer ces principes au sein du système éducatif français pour optimiser le potentiel d’apprentissage des élèves
Unraveling the Connection Between Ion Channels and Pancreatic Stellate Cell Activation
No full textInternational audienceQuiescent pancreatic stellate cells (PSCs) represent only a very low proportion of the pancreatic tissue, but their activation leads to stroma remodeling and fibrosis associated with pathologies such as chronic pancreatitis and pancreatic ductal adenocarcinoma (PDAC). PSC activation can be induced by various stresses, including acidosis, growth factors (PDGF, TGFβ), hypoxia, high pressure, or intercellular communication with pancreatic cancer cells. Activated PSC targeting represents a promising therapeutic strategy, but little is known regarding the molecular mechanisms underlying the activation of PSCs. Identification of new biomarkers of PSC activation associated with desmoplasia in chronic pancreatitis and PDAC could lead to new therapeutic targets for exocrine pancreatic disease treatments. Ion channels and transporters are transmembrane proteins involved in numerous physiological and pathological processes, including PDAC. They are well known to act as biosensors of the tissue microenvironment, and they can be easily accessible for drugs. However, their role in PSC activation is not fully understood. In this review, we briefly discuss the role of activated PSCs in pancreas inflammation and pathological fibrosis (associated with chronic pancreatitis and PDAC), and we describe the role of specific ion channels and transporters (Ca2+, K+, Na+ and Cl-) in these processes in the light of recent literature
A non-equilibrium species distribution model reveals unprecedented depth of time lag responses to past environmental change trajectories
No full textInternational audiencePrevious studies have demonstrated legacy effects of current species distributions to past environmental conditions, but the temporal extent of such time lag dynamics remains unknown. Here, we have developed a non-equilibrium SDM approach quantifying the temporal extent that must be taken into account to capture 95 % of the effect that a given time series of past environmental conditions has on the current distribution of a species. We applied this approach on the distribution of 92 European forest birds in response to past trajectories of change in forest cover and climate. We found that non-equilibrium SDMs outperformed traditional SDMs for 95 % of the species. Nonequilibrium SDMs suggest unprecedented long-lasting effects of past global changes (average time lag extent ranged from 9 years to 231 years). This framework can help to relax the equilibrium 3 hypothesis of traditional SDMs and to improve future predictions of biodiversity redistribution in response to global changes
Cover Feature: The ARTISTIC Battery Manufacturing Digitalization Initiative: From Fundamental Research to Industrialization (Batteries & Supercaps 1/2025)
No full textInternational audienceThe Cover Feature represents the whole ARTISTIC project workflow to optimize battery manufacturing process parameters. Synthetic data (produced by the physics-based manufacturing modeling chain) and experimental data are used to train surrogate models by using different machine learning techniques at the different manufacturing stages: mixing & slurry, coating & drying, calendering, electrolyte filling and performance. Then, optimizers, such as Bayesian, are used to determine the best input parameters to optimize output battery properties. More information can be found in the Concept by A. A. Franco and co-workers (DOI: 10.1002/batt.202400385)