100 research outputs found

    Exploring the antimicrobial properties of dark-operating ceramic-based nanocomposite materials for the disinfection of indoor air

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    International audienceAs people spend more and more time inside, the quality of indoor air becomes crucial matter. This study explores the germicidal potential of two dark-operating germicidal composite materials designed to be applied for the indoor air disinfection under flow conditions. The first material, MnO 2 /AlPO 4 /γ-Al 2 O 3 beads, is a donor-acceptor interactive composite capable of creating hydroxyl radicals HO.. The second one is a ZnO/γ-Al 2 O 3 material with inter-cropped hexagons on its surface. To determine the antimicrobial efficiency of these materials in lifelike conditions, a pilot device was constructed that allows the test of the materials in dynamic conditions and agar diffusion inhibitory tests were also conducted. The results of the tests showed that the MnO 2 /AlPO 4 /γ-Al 2 O 3 material has a germicidal effect in static conditions whereas ZnO/γ-Al 2 O 3 does not. In dynamic conditions, the oxidizing MnO 2 / AlPO 4 /γ-Al 2 O 3 material is the most efficient when using low air speed whereas the ZnO/γ-Al 2 O 3 one becomes more efficient than the other materials when increasing the air linear speed. This ZnO/γ-Al 2 O 3 dark-operating germicidal material manifests the ability to proceed the mechanical destruction of bacterial cells. Actually, the antimicrobial efficiency of materials in dynamic conditions varies regarding the air speed through the materials and that static tests are not representative of the behavior of the material for air disinfection. Depending on the conditions, the best strategy to inactivate microorganisms changes and abrasive structures are a field that needs further exploration as they are in most of the conditions tested the best way to quickly decrease the number of microorganisms

    Is the deciduous/permanent molar enamel thickness ratio a taxon-specific indicator in extant and extinct hominids?

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    In Primates, enamel thickness variation stems from an evolutionary interplay between functional/adaptive constraints (ecology) and the strict control mechanisms of the morphogenetic program. Most studies on primate enamel thickness have primarily considered the permanent teeth, while the extent of covariation in tooth enamel thickness distribution between deciduous and permanent counterparts remains poorly investigated. In this test study on nine extant and fossil hominids we investigated the degree of covariation in enamel proportions between 25 pairs of mandibular dm2 and M1 by a so-called “lateral enamel thickness diphyodontic index”. The results did not provide an unambiguous picture, but rather suggest complex patterns likely resulting from the influence of many interactive factors. Future research should test the congruence of the “diphyodontic signal” between the anterior and the postcanine dentition, as well as between enamel and the enamel-dentine junction topography

    Observations in situ des états de mer depuis l'embouchure jusqu'à l'intérieur du Bassin d'Arcachon : mers de vent, houles et ondes infragravitaires

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    Les embouchures tidales sont des environnements très dynamiques soumises à la fois aux forçages associés aux vagues, aux courants de marée et à l'hydrologie continentale. L'association de ces dynamiques rend la compréhension fine des processus hydrosédimentaires et l'expression des aléas érosion ou submersion particulièrement complexes. Or, et de surcroît en conditions énergétiques lors de la période hivernale, il existe peu de données hydrodynamiques in situ du fait des complexités logistiques liées à l'étendue, à l'accessibilité, à la rapidité et l'ampleur des évolutions morphosédimentaires. Cette contribution détaille les données acquises dans le cadre du projet ARCADE, lors de deux campagnes de mesures long terme réalisées pendant les hivers 2021 et 2022. Les données de vagues, de courants et de marée ont été acquises de manière simultanée depuis le large jusqu'à l'intérieur du Bassin d'Arcachon. Ces jeux de données permettent d'améliorer les connaissances sur la complexité des processus associés à la propagation des vagues et leurs transformations du large vers l'intérieur de la lagune. Un effort particulier est mis ici sur la caractérisation des ondes infragravitaires (ondes longues allant de plusieurs dizaines de secondes à plusieurs minutes) depuis l'embouchure jusqu'au fond du Bassin et du clapot (ondes courtes générées localement dont les longueurs d'ondes sont inférieures à 4 s) dans le bassin lors de différentes conditions de forçage de vent, de marée et de houle au large

    A Neanderthal from the Central Western Zagros, Iran. Structural reassessment of the Wezmeh 1 maxillary premolar

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    Wezmeh Cave, in the Kermanshah region of Central Western Zagros, Iran, produced a Late Pleistocene faunal assemblage rich in carnivorans along with a human right maxillary premolar, Wezmeh 1, an unerupted tooth from an 8 ± 2 year-old individual. Uranium-series analyses of the fauna by alpha spectrometry provided age estimates between 70 and 11 ka. Crown dimensions place the tooth specimen at the upper limits of Late Pleistocene human ranges of variation. Wezmeh 1 metameric position (most likely a P3) remains uncertain and only its surficial morphology has been described so far. Accordingly, we used micro-focus X-ray tomography (12.5 μm isotropic voxel size) to reassess the metameric position and taxonomic attribution of this specimen. We investigated its endostructural features and quantified crown tissue proportions. Topographic maps of enamel thickness (ET) distribution were also generated, and semilandmark-based geometric morphometric analyses of the enamel-dentine junction (EDJ) were performed. We compared Wezmeh 1 with unworn/slightly-moderately worn P3 and P4 of European Neanderthals, Middle Paleolithic modern humans from Qafzeh, an Upper Paleolithic premolar, and Holocene humans. The results confirm that Wezmeh 1 represents a P3. Based on its internal conformation and especially EDJ shape, Wezmeh 1 aligns closely with Neanderthals and is distinct from the fossil and extant modern human pattern of our comparative samples. Wezmeh 1 is thus the first direct evidence of Neanderthal presence on the western margin of the Iranian Plateau

    Is the deciduous/permanent molar enamel thickness ratio a taxon-specific indicator in extant and extinct hominids?

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    In Primates, enamel thickness variation stems from an evolutionary interplay between functional/adaptive constraints (ecology) and the strict control mechanisms of the morphogenetic program. Most studies on primate enamel thickness have primarily considered the permanent teeth, while the extent of covariation in tooth enamel thickness distribution between deciduous and permanent counterparts remains poorly investigated. In this test study on nine extant and fossil hominids we investigated the degree of covariation in enamel proportions between 25 pairs of mandibular dm2 and M1 by a so-called “lateral enamel thickness diphyodontic index”. The results did not provide an unambiguous picture, but rather suggest complex patterns likely resulting from the influence of many interactive factors. Future research should test the congruence of the “diphyodontic signal” between the anterior and the postcanine dentition, as well as between enamel and the enamel-dentine junction topography

    Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

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    RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

    Introduction Birational involutions of P 2

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    This paper is devoted to the classification of the elements of order 2 in the group Bir P 2 of birational automorphisms of P 2, up to conjugacy. This is a classica
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