429 research outputs found

    Rapid Cooling of the Neutron Star in Cassiopeia A Triggered by Neutron Superfluidity in Dense Matter

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    We propose that the observed cooling of the neutron star in Cassiopeia A is due to enhanced neutrino emission from the recent onset of the breaking and formation of neutron Cooper pairs in the 3P2 channel. We find that the critical temperature for this superfluid transition is ~0.5x10^9 K. The observed rapidity of the cooling implies that protons were already in a superconducting state with a larger critical temperature. Our prediction that this cooling will continue for several decades at the present rate can be tested by continuous monitoring of this neutron star.Comment: Revised version, to be published in Phys. Rev. Let

    Impact of Secondary Reactive Species on the Apparent Decoupling of Poly(Ethylene Glycol) Diacrylate Hydrogel Average Mesh Size and Modulus

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    Poly(ethylene glycol) diacrylate (PEGDA) hydrogels are widely used in biotechnology due to their in situ crosslinking capacity and tunable physical properties. However, as with all single component hydrogels, the modulus of PEGDA networks cannot be tailored independently of mesh size. This interdependence places significant limitations on their use for defined, 3D cell-microenvironment studies and for certain controlled release applications. The incorporation of secondary reactive species (SRS) into PEGDA hydrogels has previously been shown to allow the identification of up to 6 PEGDA hydrogel formulations for which distinct moduli can be obtained at consistent average mesh size (or vice versa). However, the modulus and mesh size ranges which can be probed by these formulations are quite restricted. This work presents an in-depth study of SRS incorporation into PEGDA hydrogels, with the goal of expanding the space for which decoupled examination of modulus and mesh size effects is achievable. Towards this end, over 100 PEGDA hydrogels containing either N-vinyl pyrrolidone or star PEG-tetraacrylate as SRS were characterized. To our knowledge, this is the first study to demonstrate that SRS incorporation allows for the identification of a number of modulus ranges that can be probed at consistent average mesh size (or vice versa)

    Thrombose du sinus lateral et de la veine jugulaire apres un traumatisme cranien ferme

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    Introduction Les traumatismes crâniens fermés représentent une étiologie exceptionnelle des thromboses veineuses cérébrales (TVC). Seule une trentaine de cas sont rapportés, contrastant avec la grande fréquence des traumatismes crâniens. Cette situation pose des difficultés diagnostiques pouvant expliquer le pronostic relativement mauvais des TVC post traumatiques.Objectif Rapporter un cas de thrombose veineuse après un traumatisme crânien fermé.Observation Un patient de 23 ans suivi pour une schizophrénie, a présenté suite à une tentative de suicide, un traumatisme crânien fermé sans anomalie clinique ou à la TDM cérébrale initiale. Après un intervalle de 48 heures, un syndrome d’hypertension intracrânienne est apparu de façon rapide. Une thrombose du sinus latéral droit, étendue à la veine jugulaire a été découverte fortuitement sur la TDM cérébrale et confirmée par l’angio-IRM. Le reste du bilan étiologique de cette TVC est resté négatif et les anticoagulants ont permis une amélioration rapide des symptômes.Conclusion Dans les suites d’un traumatisme crânien, l’apparition de symptômes neurologiques, en particulier d’une HTIC doit faire rechercher une TVC après avoir éliminé des causes plus classiques à ce contexte (hématomes intracrâniens).Mots clés : Thrombose veineuse cérébrale; traumatisme crânien; anticoagulants

    A deterministic method for particle sorting by dynamic acoustic fields

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    This paper investigates the dynamic acoustic sorting method from a theoretical perspective. Analytical equations of motion and numerical simulations have been used to optimize parameters for sorting various particle mixtures. The effect of changes in field parameters as frequency or voltage on efficient sorting has been investigated. Experiments have been carried out to verify theoretical findings

    PDMS\u3csub\u3estar\u3c/sub\u3e-PEG Hydrogels Prepared Via Solvent-Induced Phase Separation (SIPS) and Their Potential Utility as Tissue Engineering Scaffolds

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    Inorganic-organic hydrogels based on methacrylated star polydimethylsiloxane (PDMSstar-MA) and diacrylated poly(ethylene glycol) (PEG-DA) macromers were prepared via solvent-induced phase separation (SIPS). The macromers were combined in a dichloromethane precursor solution and sequentially photopolymerized, dried and hydrated. The chemical and physical properties of the hydrogels were further tailored by varying the number average molecular weight (Mn) of PEG-DA (Mn = 3.4k and 6k g mol-1) as well as the weight percent ratio of PDMSstar-MA (Mn = 7k g mol-1) to PEG-DA from 0:100 to 20:80. Compared to analogous hydrogels fabricated from aqueous precursor solutions, SIPS produced hydrogels with a macroporous morphology, a more even distribution of PDMSstar-MA, increased modulus and enhanced degradation rates. The morphology, swelling ratio, mechanical properties, bioactivity, non-specific protein adhesion, controlled introduction of cell adhesion, and cytocompatibility of the hydrogels were characterized. As a result of their tunable properties, this library of hydrogels is useful to study material-guided cell behavior and ultimate tissue regeneration

    Musculoskeletal Injury in American Football: A Bibliometric Analysis of the Most Cited Articles.

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    BACKGROUND: Textbook knowledge and clinical dogma are often insufficient for effective evidence-based decision making when treating musculoskeletal injuries in American football players, given the variability in presentation and outcomes across different sports and different levels of competition. Key evidence can be drawn directly from high-quality published articles to make the appropriate decisions and recommendations for each athlete\u27s unique situation. PURPOSE: To identify and analyze the 50 most cited articles related to football-related musculoskeletal injury to provide an efficient tool in the arsenal of trainees, researchers, and evidence-based practitioners alike. STUDY DESIGN: Cross-sectional study. METHODS: The ISI Web of Science and SCOPUS databases were queried for articles pertaining to musculoskeletal injury in American football. For each of the top 50 most cited articles, bibliometric elements were evaluated: citation count and density, decade of publication, journal, country, multiple publications by the same first author or senior author, article content (topic, injury area), and level of evidence (LOE). RESULTS: The mean ± SD number of citations was 102.76 ± 37.11; the most cited article, with 227 citations, was Syndesmotic Ankle Sprains published in 1991 by Boytim et al. Several authors served as a first or senior author on \u3e1 publication, including J.S. Torg (n = 6), J.P. Bradley (n = 4), and J.W. Powell (n = 4). The CONCLUSION: The results of this study highlight the need for more prospective research surrounding the management of football-related injury. The low overall number of articles on upper extremity injury (n = 4) also highlights an area for further research

    Candida auris: a literature review

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    Background: Emerging pathogen Candida auris has been associated with nosocomial outbreaks demonstrating widespread antifungal resistance. This microorganism is associated with systemic infections with a high mortality rate, and studies that contribute to a better understanding of this agent are important. Objectives: The present article aimed to carry out bibliographic research on Candida auris. Therefore, a literature search was carried out between January 2018 and January 2022, applying the following: C. auris; Candida auris and Infection, in Portuguese, English and Spanish. This review considers the available literature on C. auris and highlights key unknowns, which will provide guidance for future work in this field. Results: The data collected in the present review allowed us to divide the theme into topics on Pathophysiology, Epidemiology/clinical and drug resistance mechanisms, so that the understanding of Candida auris can be better detailed and understood. Conclusion: The predilection of C. auris by the most vulnerable and immunosuppressed patients or with comorbidities and with the potential to cause invasive and bloodstream infections with a propensity to cause outbreaks and concerns regarding resistance to antifungal agents, the fungus Candida auris, is of increasing clinical relevance. The increase in the number of detected cases and the occurrence of strains with multiple drug resistance prove to be worrisome, and applied research is essential to contribute to the knowledge of this strain and effective therapy

    A transitional fossil mite (Astigmata: Levantoglyphidae fam. n.) from the early Cretaceous suggests gradual evolution of phoresy-related metamorphosis

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    Abstract Metamorphosis is a key innovation allowing the same species to inhabit different environments and accomplish different functions, leading to evolutionary success in many animal groups. Astigmata is a megadiverse lineage of mites that expanded into a great number of habitats via associations with invertebrate and vertebrate hosts (human associates include stored food mites, house dust mites, and scabies). The evolutionary success of Astigmata is linked to phoresy-related metamorphosis, namely the origin of the heteromorphic deutonymph, which is highly specialized for phoresy (dispersal on hosts). The origin of this instar is enigmatic since it is morphologically divergent and no intermediate forms are known. Here we describe the heteromorphic deutonymph of Levantoglyphus sidorchukae n. gen. and sp. (Levantoglyphidae fam. n.) from early Cretaceous amber of Lebanon (129 Ma), which displays a transitional morphology. It is similar to extant phoretic deutonymphs in its modifications for phoresy but has the masticatory system and other parts of the gnathosoma well-developed. These aspects point to a gradual evolution of the astigmatid heteromorphic morphology and metamorphosis. The presence of well-developed presumably host-seeking sensory elements on the gnathosoma suggests that the deutonymph was not feeding either during phoretic or pre- or postphoretic periods
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