3,617 research outputs found

    Nitrogen Isotope Fractionation During Archaeal Ammonia Oxidation: Coupled Estimates From Measurements of Residual Ammonium and Accumulated Nitrite

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    The naturally occurring nitrogen (N) isotopes,N-15 and(14)N, exhibit different reaction rates during many microbial N transformation processes, which results in N isotope fractionation. Such isotope effects are critical parameters for interpreting natural stable isotope abundances as proxies for biological process rates in the environment across scales. The kinetic isotope effect of ammonia oxidation (AO) to nitrite (NO2-), performed by ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB), is generally ascribed to the enzyme ammonia monooxygenase (AMO), which catalyzes the first step in this process. However, the kinetic isotope effect of AMO, or epsilon(AMO), has been typically determined based on isotope kinetics during product formation (cumulative product, NO2-) alone, which may have overestimated epsilon(AMO)due to possible accumulation of chemical intermediates and alternative sinks of ammonia/ammonium (NH3/NH4+). Here, we analyzed(15)N isotope fractionation during archaeal ammonia oxidation based on both isotopic changes in residual substrate (RS, NH4+) and cumulative product (CP, NO2-) pools in pure cultures of the soil strainNitrososphaera viennensisEN76 and in highly enriched cultures of the marine strainNitrosopumilus adriaticusNF5, under non-limiting substrate conditions. We obtained epsilon(AMO)values of 31.9-33.1 parts per thousand for both strains based on RS (delta(NH4+)-N-15) and showed that estimates based on CP (delta(NO2-)-N-15) give larger isotope fractionation factors by 6-8 parts per thousand. Complementary analyses showed that, at the end of the growth period, microbial biomass was(15)N-enriched (10.1 parts per thousand), whereas nitrous oxide (N2O) was highly(15)N depleted (-38.1 parts per thousand) relative to the initial substrate. Although we did not determine the isotope effect of NH(4)(+)assimilation (biomass formation) and N2O production by AOA, our results nevertheless show that the discrepancy between epsilon(AMO)estimates based on RS and CP might have derived from the incorporation of(15)N-enriched residual NH(4)(+)after AMO reaction into microbial biomass and that N2O production did not affect isotope fractionation estimates significantly

    Acute Neuromuscular, Physiological and Performance Responses After Strength Training in Runners: A Systematic Review and Meta-Analysis

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    Background: Strength training (ST) is commonly used to improve muscle strength, power, and neuromuscular adaptations and is recommended combined with runner training. It is possible that the acute effects of the strength training session lead to deleterious effects in the subsequent running. The aim of this systematic review and meta-analysis was to verify the acute effects of ST session on the neuromuscular, physiological and performance variables of runners. Methods: Studies evaluating running performance after resistance exercise in runners in the PubMed and Scopus databases were selected. From 6532 initial references, 19 were selected for qualitative analysis and 13 for meta-analysis. The variables of peak torque (PT), creatine kinase (CK), delayed-onset muscle soreness (DOMS), rating of perceived exertion (RPE), countermovement jump (CMJ), ventilation (VE), oxygen consumption (VO2), lactate (La) and heart rate (HR) were evaluated. Results: The methodological quality of the included studies was considered reasonable; the meta-analysis indicated that the variables PT (p = 0.003), DOMS (p < 0.0001), CK (p < 0.0001), RPE (p < 0.0001) had a deleterious effect for the experimental group; for CMJ, VE, VO2, La, FC there was no difference. By qualitative synthesis, running performance showed a reduction in speed for the experimental group in two studies and in all that assessed time to exhaustion. Conclusion: The evidence indicated that acute strength training was associated with a decrease in PT, increases in DOMS, CK, RPE and had a low impact on the acute responses of CMJ, VE, VO2, La, HR and submaximal running sessions. Keywords: Aerobic performance; Competitive training; Running; Strength training

    Satisfação materna com o cuidado da enfermeira materno-infantil em Campeche, México

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    OBJECTIVE: Evaluate and compare maternal-satisfaction (global and areas) with maternal-child nursing care (MSMINC) and to explore the relationship of MSMINC with wait time, length of visit, and maternal age and education. METHODS: Cross-sectional descriptive study comprising 213 mothers. Group 1 (n = 84), mothers of children agedEl objetivo de este estudio fue evaluar y comparar la satisfacción materna (global/áreas) con el cuidado de la enfermera materno infantil (MSMINC) y explorar la relación de MSMINC con el tiempo de espera, duración de la visita, edad y educación materna. Se trata de un estudio descriptivo transversal. Participaron 213 madres. Grupo 1, n = 84 madres de niñosOBJETIVO: Avaliar e comparar a satisfação materna (global e áreas) com o cuidado da enfermeira materno-infantil (SMAEMI) e explorar a relação da SMAEMI com o tempo de espera e duração da visita, idade e educação da mãe. MÉTODOS: ESTUdo descritivo-transversal com a participação de 213 mães. Grupo 1, n = 84 mães de criança

    Study of the immunologic response of marine-derived collagen and gelatin extracts for tissue engineering applications

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    9 pages, 3 figures, 2 tablesThe host immunologic response to a specific material is a critical aspect when considering it for clinical implementation. Collagen and gelatin extracted from marine sources have been proposed as biomaterials for tissue engineering applications, but there is a lack of information in the literature about their immunogenicity. In this work, we evaluated the immune response to collagen and/or gelatin from blue shark and codfish, previously extracted and characterized. After endotoxin evaluation, bone marrow-derived macrophages were exposed to the materials and a panel of pro- and anti-inflammatory cytokines were evaluated both for protein quantification and gene expression. Then, the impact of those materials in the host was evaluated through peritoneal injection in C57BL/6 mice. The results suggested shark collagen as the less immunogenic material, inducing low expression of pro-inflammatory cytokines as well as inducible nitric oxide synthase (encoded by Nos2) and high expression of Arginase 1 (encoded by Arg1). Although shark gelatin appeared to be the material with higher pro-inflammatory expression, it also presents a high expression of IL-10 (anti-inflammatory cytokine) and Arginase (both markers for M2-like macrophages). When injected in the peritoneal cavity of mice, our materials demonstrated a transient recruitment of neutrophil, being almost non-existent after 24 hours of injection. Based on these findings, the studied collagenous materials can be considered interesting biomaterial candidates for regenerative medicine as they may induce an activation of the M2-like macrophage population, which is involved in suppressing the inflammatory processes promoting tissue remodelingThe authors would like to acknowledge to European Union for the financial support under the scope of European Regional Development Fund (ERDF) through the projects 0302_CVMAR_I_1_P and 0474_BLUEBIOLAB_1_E (program INTERREG España-Portugal 2014/2020). Funding from the Portuguese Foundation for Science and Technology for the grant of A. L. Alves (Ana Luísa Alves) under Doctoral Programme Do*Mar (PD/BD/127995/2016) is also acknowledgedPeer reviewe

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

    Single origin of sex chromosomes and multiple origins of B chromosomes in fish genus Characidium

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    Chromosome painting with DNA probes obtained from supernumerary (B) and sex chromosomes in three species of fish genus Characidium (C. gomesi, C. pterostictum and C. oiticicai) showed a close resemblance in repetitive DNA content between B and sex chromosomes in C. gomesi and C. pterostictum. This suggests an intraspecific origin for B chromosomes in these two species, probably deriving from sex chromosomes. In C. oiticicai, however, a DNA probe obtained from its B chromosome hybridized with the B but not with the A chromosomes, suggesting that the B chromosome in this species could have arisen interspecifically, although this hypothesis needs further investigation. A molecular phylogenetic analysis performed on nine Characidium species, with two mtDNA genes, showed that the presence of heteromorphic sex chromosomes in these species is a derived condition, and that their origin could have been unique, a conclusion also supported by interspecific chromosome painting with a CgW probe derived from the W chromosome in C. gomesi. Summing up, our results indicate that whereas heteromorphic sex chromosomes in the genus Characidium appear to have had a common and unique origin, B chromosomes may have had independent origins in different species. Our results also show that molecular phylogenetic analysis is an excellent complement for cytogenetic studies by unveiling the direction of evolutionary chromosome changes.This research was funded by grants from the State of Sao Paulo Research Foundation (FAPESP) to EAS (2013/02143-3), grants from National Council for Research and Development (CNPq) to FF (480449/2012-0), and by Coordenacao de Aperfeicoamento de Pessoal de Nıvel Superior (CAPES)

    Foreign direct investment and institutional reform : evidence and an application to Portugal

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    We examine the role of geographic, economic, and institutional factors in attracting Foreign Direct Investment (FDI) in Europe, using a cross-section of inward bilateral investments. We estimate and assess the expected benefits, the required reform efforts, and the efficiency of reform options corresponding to a con- vergence of Portuguese institutions to EU standards. We conclude that improving home institutions is likely to have a quantitatively very significant role in attracting FDI. Geographical and market size factors also play a role. Reforms promoting the independence of financial institutions and a leaner bureaucracy, lowering political risk and corruption, and improving the investment code may significantly affect the amount of bilateral inward FDI that is targeted to Portugal.info:eu-repo/semantics/publishedVersio
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