271 research outputs found

    Draft genome sequences of 11 Staphylococcus epidermidis strains isolated from wild mouse species

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    We report here the draft genome sequences of 11 strains of Staphylococcus epidermidis, a common bacterium inhabiting the skin of humans and other animals. These isolates, obtained from five mouse species, provide valuable information on the native Staphylococcus spp. of this important model organism and form a basis for studying host-bacterial interactions in their natural environment

    Horizontal gene transfer-mediated bacterial strain variation affects host fitness in Drosophila

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    How microbes affect host fitness and environmental adaptation has become a fundamental research question in evolutionary biology. To better understand the role of microbial genomic variation for host fitness, we tested for associations of bacterial genomic variation and Drosophila melanogaster offspring number in a microbial Genome Wide Association Study (GWAS)

    Scalable Synthesis of Microsized, Nanocrystalline Zn0.9_{0.9}Fe0.1_{0.1}O-C Secondary Particles and Their Use in Zn0.9_{0.9}Fe0.1_{0.1} O-C/LiNi0.5_{0.5}Mn1.5_{1.5}O4_{4} Lithium-Ion Full Cells

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    Conversion/alloying materials (CAMs) are a potential alternative to graphite as Li‐ion anodes, especially for high‐power performance. The so far most investigated CAM is carbon‐coated Zn0.9_{0.9}Fe0.1_{0.1}O, which provides very high specific capacity of more than 900 mAh g−1^{-1} and good rate capability. Especially for the latter the optimal particle size is in the nanometer regime. However, this leads to limited electrode packing densities and safety issues in large‐scale handling and processing. Herein, a new synthesis route including three spray‐drying steps that results in the formation of microsized, spherical secondary particles is reported. The resulting particles with sizes of 10–15 ÎŒm are composed of carbon‐coated Zn0.9_{0.9}Fe0.1_{0.1}O nanocrystals with an average diameter of approximately 30–40 nm. The carbon coating ensures fast electron transport in the secondary particles and, thus, high rate capability of the resulting electrodes. Coupling partially prelithiated, carbon‐coated Zn0.9_{0.9}Fe0.1_{0.1}O anodes with LiNi0.5_{0.5}Mn1.5_{1.5}O4_{4} cathodes results in cobalt‐free Li‐ion cells delivering a specific energy of up to 284 Wh kg−1^{-1} (at 1 C rate) and power of 1105 W kg−1 (at 3 C) with remarkable energy efficiency (>93 % at 1 C and 91.8 % at 3 C)

    Reducing Capacity and Voltage Decay of Co-Free Li1.2Ni0.2Mn0.6O2 as Positive Electrode Material for Lithium Batteries Employing an Ionic Liquid-Based Electrolyte

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    Lithium‐rich layered oxides (LRLOs) exhibit specific capacities above 250 mAh g−1^{-1}, i.e., higher than any of the commercially employed lithium‐ion‐positive electrode materials. Such high capacities result in high specific energies, meeting the tough requirements for electric vehicle applications. However, LRLOs generally suffer from severe capacity and voltage fading, originating from undesired structural transformations during cycling. Herein, the eco‐friendly, cobalt‐free Li1.2_{1.2}Ni0.2_{0.2}Mn0.6_{0.6}O2_{2} (LRNM), offering a specific energy above 800 Wh kg−1^{-1} at 0.1 C, is investigated in combination with a lithium metal anode and a room temperature ionic liquid‐based electrolyte, i.e., lithium bis(trifluoromethanesulfonyl)imide and N‐butyl‐N‐methylpyrrolidinium bis(fluorosulfonyl)imide. As evidenced by electrochemical performance and high‐resolution transmission electron microscopy, X‐ray photoelectron spectroscopy, and online differential electrochemical mass spectrometry characterization, this electrolyte is capable of suppressing the structural transformation of the positive electrode material, resulting in enhanced cycling stability compared to conventional carbonate‐based electrolytes. Practically, the capacity and voltage fading are significantly limited to only 19% and 3% (i.e., lower than 0.2 mV per cycle), respectively, after 500 cycles. Finally, the beneficial effect of the ionic liquid‐based electrolyte is validated in lithium‐ion cells employing LRNM and Li4_{4}Ti5_{5}O12_{12}. These cells achieve a promising capacity retention of 80% after 500 cycles at 1 C

    The feedback between selection and demography shapes genomic diversity during coevolution

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    Species interactions and coevolution are integral to ecological communities, but we lack empirical information on when and how these interactions generate and purge genetic diversity. Using genomic time series data from host-virus experiments, we found that coevolution occurs through consecutive selective sweeps in both species, with temporal consistency across replicates. Sweeps were accompanied by phenotypic change (resistance or infectivity increases) and expansions in population size. In the host, population expansion enabled rapid generation of genetic diversity in accordance with neutral processes. Viral molecular evolution was, in contrast, confined to few genes, all putative targets of selection. This study demonstrates that molecular evolution during species interactions is shaped by both eco-evolutionary feedback dynamics and interspecific differences in how genetic diversity is generated and maintained

    Stress induced polarization of immune-neuroendocrine phenotypes in Gallus gallus

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    Immune-neuroendocrine phenotypes (INPs) stand for population subgroups differing in immune-neuroendocrine interactions. While mammalian INPs have been characterized thoroughly in rats and humans, avian INPs were only recently described in Coturnix coturnix (quail). To assess the scope of this biological phenomenon, herein we characterized INPs in Gallus gallus (a domestic hen strain submitted to a very long history of strong selective breeding pressure) and evaluated whether a social chronic stress challenge modulates the individuals’ interplay affecting the INP subsets and distribution. Evaluating plasmatic basal corticosterone, interferon-Îł and interleukin-4 concentrations, innate/acquired leukocyte ratio, PHA-P skin-swelling and induced antibody responses, two opposite INP profiles were found: LEWIS-like (15% of the population) and FISCHER-like (16%) hens. After chronic stress, an increment of about 12% in each polarized INP frequency was found at expenses of a reduction in the number of birds with intermediate responses. Results show that polarized INPs are also a phenomenon occurring in hens. The observed inter-individual variation suggest that, even after a considerable selection process, the population is still well prepared to deal with a variety of immune-neuroendocrine challenges. Stress promoted disruptive effects, leading to a more balanced INPs distribution, which represents a new substrate for challenging situations.Fil: Nazar, Franco Nicolas. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - CĂłrdoba. Instituto de Investigaciones BiolĂłgicas y TecnolĂłgicas. Universidad Nacional de CĂłrdoba. Facultad de Ciencias Exactas, FĂ­sicas y Naturales. Instituto de Investigaciones BiolĂłgicas y TecnolĂłgicas; ArgentinaFil: Estevez, Inma. Centro de InvestigaciĂłn. Neiker - Tecnalia; EspañaFil: Correa, Silvia Graciela. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂ­mica ClĂ­nica e InmunologĂ­a; ArgentinaFil: Marin, Raul Hector. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - CĂłrdoba. Instituto de Investigaciones BiolĂłgicas y TecnolĂłgicas. Universidad Nacional de CĂłrdoba. Facultad de Ciencias Exactas, FĂ­sicas y Naturales. Instituto de Investigaciones BiolĂłgicas y TecnolĂłgicas; Argentin

    Population genetics and demography of the endemic mouse species of Cyprus, Mus cypriacus

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    Mus cypriacus is one of three small palaeoendemic mammals that have survived the Mediterranean islands’ anthropization. This species, endemic to Cyprus, was described in 2006 and stands out as one of the last mammal species to have been discovered in Europe. Despite scarce data on its genetics, ecology, and life-history traits, Mus cypriacus is assessed as Least Concern LC in the IUCN Red List, partly due to its morphological similarity with the sympatric house mouse that prevented earlier identification. Our study uses mitochondrial and microsatellite markers to investigate this small rodent's population genetic structure and diversity. Our analysis did not identify any population genetic structure and suggested a high genetic diversity across Cyprus. When inferring habitat preference using sample locations, it appeared that M. cypriacus utilizes a diverse variety of habitats, covering more than 80% of the island. Although these results are encouraging for the conservation status of the species, they still need to be cautiously applied as potential threats may arise due to increasing habitat destruction and changes in land use. Consequently, our encouraging results should be applied judiciously. Additional ecological data are urgently needed to gain a more comprehensive understanding of this inconspicuous endemic species

    The management and outcome for patients with chronic subdural hematoma: a prospective, multicenter, observational cohort study in the United Kingdom

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    Symptomatic chronic subdural hematoma (CSDH) will become an increasingly common presentation in neurosurgical practice as the population ages, but quality evidence is still lacking to guide the optimal management for these patients. The British Neurosurgical Trainee Research Collaborative (BNTRC) was established by neurosurgical trainees in 2012 to improve research by combining the efforts of trainees in each of the United Kingdom (UK) and Ireland's neurosurgical units (NSUs). The authors present the first study by the BNTRC that describes current management and outcomes for patients with CSDH throughout the UK and Ireland. This provides a resource both for current clinical practice and future clinical research on CSDH
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