HAL Portal UO (Université d'Orléans)
Not a member yet
48841 research outputs found
Sort by
Ischemic preconditioning delayed neuromuscular fatigue development during a simulated soccer match
No full textInternational audienceObjectivesThis study investigated the effect of ischemic preconditioning (IPC) on neuromuscular fatigue etiology and physical performance during simulated soccer match play.DesignThe study followed a crossover randomized, placebo-controlled trial design.MethodsFourteen semi-professional players completed the Loughborough Intermittent Shuttle Test (LIST) preceded by either three 5 min periods of bilateral cuff inflation to 220 mmHg (IPC) or to 20 mmHg (PLA), interspersed with 5-min periods of reperfusion. Neuromuscular function, including maximal voluntary contraction (MVC), potentiated twitch (Ptw), and voluntary activation (VA), was assessed at baseline, halftime (HT), and full time (FT). Sprint performance, perceived exertion, and muscle soreness (MS) were evaluated through the LIST protocol.ResultsIPC significantly attenuated the decline in MVC at HT (p < 0.01, d = 0.7) and FT (p < 0.01, d = 1.3) compared to PLA. VA was better maintained with IPC at HT (− 8 % in PLA vs − 4 % in IPC, p < 0.01, d = 1.4) and FT (− 11 % in PLA vs − 6 % in IPC, p < 0.01, d = 1.6). Sprint performance was significantly preserved in IPC during the third (p = 0.01, d = 0.55) and sixth sets (p < 0.01, d = 1.03). Likewise, IPC reduced MS scores at FT (p < 0.01, d = 1.4) compared to PLA.ConclusionThese findings suggest that IPC effectively attenuated neuromuscular fatigue development, likely via central factors, and preserved high-intensity performance during a simulated soccer match play
A genetic fingerprint associated with durable HIV remission after interruption of antiretroviral treatment: ANRS VISCONTI/PRIMO
No full textInternational audienceBackgroundThere is currently no curative treatment for HIV-1 infection. However, some individuals (defined as posttreatment controllers) durably control viremia after the discontinuation of antiretroviral therapy (ART). Although the ability to achieve this HIV-1 remission status is enhanced by early treatment initiation, the mechanisms leading to posttreatment HIV-1 control remain unclear.MethodsWe retrospectively explored the immunogenetic characteristics of long-term posttreatment controllers from the ANRS VISCONTI study and persons monitored since primary HIV-1 infection in the ANRS PRIMO cohort and evaluated their influence on clinical parameters and outcome after ART discontinuation.FindingsWe identified a major histocompatibility complex (MHC)-related fingerprint favoring sustained HIV-1 remission. HLA-B∗35 alleles, which are associated with rapid progression to AIDS during natural HIV-1 infection, were paradoxically overrepresented among posttreatment controllers and had a positive impact on outcome after treatment discontinuation in people who began therapy during primary infection. Specifically, the influence of HLA-B∗35 alleles was observed when they were carried in combination with other HLA class I alleles expressing Bw4 and C2 ligands of killer immunoglobulin-like receptors (KIRs) in a genetic context that favors KIR education of natural killer (NK) cells (Bw4TTC2 genotype). Accordingly, posttreatment controllers with HLA-B∗35 alleles carry distinct KIR genotypes and NK cells.ConclusionsThe combination of HLA-B∗35 with Bw4TTC2 genotype, associated with KIR education of NK cells, was abundant among posttreatment HIV-1 controllers and promoted viral control after interruption of early-initiated antiretroviral treatment. These results support a role of NK cells in sustained HIV-1 remission
The insertion of Neomycin cassette impairs maternal and social behaviors in Arc/Arg3.1 knock-out mice
No full textThe Neomycin resistance cassette (Neo+) is commonly inserted in the genome of mice to generate knock-out (KO) models. The effect of gene deletion on social behaviors in mice is controversial between studies using different Neo+ and Neo- mouse lines, particularly Arc/Arg3.1 KO lines. In this study, we identified severe maternal behavior impairments in Neo+, but not Neo- Arc/Arg3.1 KO dams. These deficits resulted from reduced sociability and abnormal social information processing in Neo+ Arc/Arg3.1 KO dams, exacerbated by social communication impairments in pups. The expression of the Neo cassette product did not cause cytotoxicity, but led to altered ERK signaling, gene expression, and oxytocin system. However, oxytocin administration did not improve social impairments in Neo+ Arc/Arg3.1 KO animals. Interestingly, early social environment enrichment enhanced social interaction with familiar, but not unfamiliar conspecifics or maternal behavior. Overall, our findings reveal a major impact of the Neo cassette on behaviors, particularly social behaviors, in Arc/Arg3.1 KO mice, underscoring the need to re-examine phenotypes of animal models carrying the Neo cassette in neuroscience research
Isotopic fractionation of neon during magma degassing
No full textInternational audienceDetermining the neon isotope composition of the Earth's mantle is key to unravelling how light noble gases became part of the primordial Earth. However, accurately measuring neon abundance and isotopic composition in primary mantle melts is challenging due to the low concentration of neon, coupled with potential isotopic fractionation during transport and degassing. Interestingly, natural samples that exhibit solar-like neon isotopic compositions, ranging between the values calculated for the Sun ( 20 Ne/ 22 Ne = 13.36 ± 0.09; Heber et al., 2012) and those resulting from solar wind implantation and sputtering ( 20 Ne/ 22 Ne = 12.73; Moreira and Charnoz, 2016), support the idea that the Earth's mantle might have trapped a primordial nebula in its early formation stages. Analyses of three synthetic vesiculated glasses, produced at ∼1.7 kbar and 1200 °C using a starting material with an air-like isotopic composition ( 20 Ne/ 22 Ne = 9.81 and 21 Ne/ 22 Ne = 0.0287) fluxed with CO 2 , reveal significant isotopic fractionation of Ne within trapped vesicles. Measured values reach 20 Ne/ 22 Ne = 10.50 ± 0.14. The isotopic variations among individual vesicles align with expectations for kinetic fractionation, suggesting that degassing processes affect Ne isotope composition of basaltic melts.</div
Epigenetics in Ecology and Evolution
No full textInternational audienceGenetics and its mysterious little sister, epigenetics, have deep roots in the history of biology. Today, epigenetics is of paramount importance in not only the fundamental sciences, but also in life science applications, ranging from molecular biology, and disease diagnosis and treatment, to agriculture.Epigenetics in Ecology and Evolution traces the history of the concept of epigenetics in biology and describes the molecular mechanisms concerned. It examines the contributions that the emerging discipline of epigenetics has made to the fields of ecology and evolution, regarding both plant and animal organisms, as well as its place in our society.By exploring the importance of epigenetics at varying levels, from the cell to the organism as a whole, and even to the ecosystem, this book offers answers that are accessible to a wide audience, from scientifically curious citizens to students and professionals working in the world of biology. The aim is to enable everyone to acquire or develop a critical and informed perspective on the complex relationships between genetics and epigenetic
Interroger le concept de réforme dans les économies monétaires gauloises au second âge du Fer. Session "Reconstruire, réformer, refonder un monnayage (Antiquité-Moyen Âge)"
No full textInternational audienceDu début du IIIe siècle av. n.è, date d’apparition des premières monnaies gauloises, jusqu’à la fin du Ier siècle av. n.è et la fin des monnayages autonomes, des politiques de productions monétaires plurielles sont mises en œuvre à l’échelle de la Gaule. Alors que des changements au sein des monnayages gaulois sont manifestes et bien identifiés, le terme de « réforme » n’est jamais employé par les numismates, les archéologues ou les historiens de la monnaie. L’adoption d’un nouveau référentiel iconographique qui accompagne un changement d’étalon pondéral ou l’introduction d’un nouvel alliage pour frapper de nouvelles séries monétaires ne sont ainsi jamais interprétés sous l’angle des réformes. A partir des cas les mieux documentés, cette communication propose d’interroger le concept de réforme monétaire en Gaule au second âge du Fer
The influence of cuff location on the oxygenation and reperfusion of the foot during ischemic preconditioning: A reliability study
No full textInternational audienc
Novel insight into the potential of flavonol-enriched extracts from saffron (Crocus sativus L.) floral bio-residues as source of antioxidants agents
No full textInternational audienceCrocus sativus L. tepals, a waste obtained from saffron flowers, are of particular interest as valuable nutraceutical resource rich in phenolic compounds. The study aimed to perform for the first time a comparative analysis of the phenolic content and antioxidant potential of saffron tepals extracts (HESTs) harvested for two consecutive years from the Taliouine region of Morocco. A significant diversity in phenolic compounds concentrations comprising polyphenol, flavonoids, flavonols and anthocyanins, was noted among HESTs. Notably, the harvest year had no effect on the chemical composition, characterized by Ultra High-Performance Liquid Chromatography-Mass Spectrometry (UHPLC-MS), which demonstrated stability and abundance of flavonol compounds such as kaempferol along with its derivates, quercetin, and isorhamnetin derivates. Similarly, the antioxidant activity, assessed using DPPH (2,2-diphenyl-1-picryl-hydrazyl), FRAP (Ferric reducing power) and TAC (Total antioxidant capacity) assays, remained consistent. The phenolic profile and the antioxidant potential demonstrated a strong correlation. Our findings highlight the potential use of saffron bioresidues as a renewable and stable resource of natural antioxidants with therapeutic benefits. (c) 2025 SAAB. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies
Quelques abris de la Défense passive orléanaise
No full textInternational audienceLes trois exemples d’abris présentés ont été observés dans le cadre d’une prospection thématique (Alix 2017) et d’une opération d’archéologie préventive (Millereux 2023). Au 36 rue de la Borde, une vaste cave-carrière souterraine (XVIIIe ou XIXe s.) conservent les vestiges de plusieurs aménagements et équipements liés à son usage en tant qu’abri collectif de la Défense passive. Dans le jardin d’une maison située 7 Chemin du Halage a été observée une tranché-abri en béton armé, probablement à usage familial, dont la construction aurait pu être menée ou supervisée par le propriétaire de l’habitation, dont l’étude en archive a montré qu’il avait eu une carrière militaire dans le génie puis dans défense contre les attaques aériennes (Mercé 2024 : 50-57). Enfin, la préparation d’un diagnostic archéologique en 2023 dans le jardin de l’Évêché a été l’occasion de se pencher sur la présence d’une tranchée-abri collective de la Défense passive dont la construction (1939), les travaux d’entretien (1944) et le démantèlement (1945) sont bien documentés. Un linéaire à crémaillère révélé à son emplacement par la prospection géophysique pourrait éventuellement correspondre à cette tranchée.Alix 2017Alix C. (dir.) - SICAVOR : Système d’Information Contextuel sur les Caves d’Orléans (2015-2017), rapport de prospection thématique pluriannuelle, Ville d’Orléans / SRA Centre-Val de Loire, 3 vol.Millereux 2023Millereux C. (dir.), Thion C. (collab.) - Orléans, jardin de l’Évêché, rapport de diagnostic archéologique, Pôle d’archéologie, Ville d’Orléans / SRA Centre-Val de Loire, 205 p.Mercé 2024Mércé G. (dir.) - Archéologie des co,nflits contemporains en régions Île-de-France et Centre-Val de Loire, rapport de programme collectif de recherche, 3e année d’opération 2023, 163 p
Une approche déclarative pour le clustering explicable sous contraintes
No full textNational audienceLe clustering est souvent vu comme une tâche non supervisée, exploratoire, aidant un expert à comprendre la structure de ses données. Des contraintes fondées sur des connaissances expertes peuvent être introduites afin d'aligner les résultats avec ses attentes. Cependant leur acquisition reste complexe, rendant l'explication du clustering essentielle pour ajuster les paramètres et découvrir de nouvelles informations.Nous abordons le problème du clustering explicable en considérant deux espaces de représentation : l'un pour le clustering et l'autre pour les explications. Notre méthode ECS (Explainability-driven Cluster Selection) vise à produire un clustering de qualité, tout en étant explicable par des motifs couvrant la majorité des instances d'un cluster et les discriminant des autres. Elle s'appuie sur le clustering ensemble et un nouveau modèle de programmation par contraintes (PPC) pour la sélection des clusters et des explications