2,096 research outputs found

    The effect of a stellar magnetic variation on the jet velocity

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    Stellar jets are normally constituted by chains of knots with some periodicity in their spatial distribution, corresponding to a variability of order of several years in the ejection from the protostar/disk system. A widely accepted theory for the presence of knots is related to the generation of internal working surfaces due to variations in the jet ejection velocity. In this paper we study the effect of variations in the inner disk-wind radius on the jet ejection velocity. We show that a small variation in the inner disk-wind radius produce a variation in the jet velocity large enough to generate the observed knots. We also show that the variation in the inner radius may be related to a variation of the stellar magnetic field.Comment: 5 pages, 3 figures, accepted for publication in Ap

    Sulbactam pivoxil powder attributes and compatibility study with excipients

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    Background: Sulbactam pivoxil is an irreversible ÎČ-lactamase inhibitor that can be used with ÎČ-lactam antibiotics to improve antibacterial therapy by the oral route. Relevant properties of this drug for pharmaceutical manufacturing are not available in the open literature. In this work, a solid-state characterization of sulbactam pivoxil at the molecular, particle, and bulk levels was performed. Results: Particles exhibited a mean diameter of about 350 ÎŒm, irregular shape crystals, and good flow properties. This work presents for the first time the crystal structure of this ÎČ-lactamase inhibitor obtained by X-ray diffraction analysis. Fourier-transform infrared results showed the characteristic bands of aliphatic hydrocarbons and ester groups. The differential scanning calorimetry curve exhibited a sharp endothermic peak at 109 °C corresponding to sulbactam pivoxil melting. The thermogravimetric curve revealed a mass loss at 184 °C associated with a decomposition process. This powder showed a moisture content of 0.34% and a water activity of 0.463. Potential interactions between sulbactam pivoxil and common pharmaceutical excipients were evaluated by thermal analysis. The endothermic peak and the enthalpies of melting were preserved in almost all the analyzed mixtures. Conclusion: The powder was constituted by micro-sized crystals of sulbactam pivoxil that had suitable physicochemical properties for processing in controlled humidity environments. Thermal analyses suggested that sulbactam pivoxil is compatible with most of the evaluated excipients. The information obtained in the present study is relevant for the development, manufacturing, and storage of formulations that include sulbactam pivoxil.Fil: Gallo, Loreana Carolina. Universidad Nacional del Sur. Departamento de BiologĂ­a, BioquĂ­mica y Farmacia; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - BahĂ­a Blanca. Planta Piloto de IngenierĂ­a QuĂ­mica. Universidad Nacional del Sur. Planta Piloto de IngenierĂ­a QuĂ­mica; ArgentinaFil: GonzĂĄlez Vidal, Noelia LujĂĄn. Universidad Nacional del Sur. Departamento de BiologĂ­a, BioquĂ­mica y Farmacia; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - BahĂ­a Blanca; ArgentinaFil: Ferreira, Fabio F.. Universidad Federal do Abc; BrasilFil: RamĂ­rez Rigo, MarĂ­a Veronica. Universidad Nacional del Sur. Departamento de BiologĂ­a, BioquĂ­mica y Farmacia; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - BahĂ­a Blanca. Planta Piloto de IngenierĂ­a QuĂ­mica. Universidad Nacional del Sur. Planta Piloto de IngenierĂ­a QuĂ­mica; Argentin

    Head‐to‐Head comparison of consensus‐recommended platelet function tests to assess P2Y12 Inhibition : insights for multi‐center trials

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    The vasodilator‐associated stimulated phosphoprotein (VASP) phosphorylation level is a highly specific method to assess P2Y12 receptor inhibition. Traditionally, VASP phosphorylation is analyzed by flow cytometry, which is laborious and restricted to specialized laboratories. Recently, a simple ELISA kit has been commercialized. The primary objective of this study was to compare the performance of VASP assessment by ELISA and flow cytometry in relation to functional platelet aggregation testing by MultiplateÂź whole‐blood aggregometry. Blood from 24 healthy volunteers was incubated with increasing concentration of a P2Y12 receptor inhibitor (AR‐C 66096). Platelet function testing was carried out simultaneously by MultiplateÂź aggregometry and by VASP assessment through ELISA and flow cytometry. As expected, increasing concentrations of the P2Y12 receptor inhibitor induced a proportional inhibition of platelet aggregation and P2Y12 receptor activation across the modalities. Platelet reactivity index values of both ELISA‐ and flow cytometry‐ based VASP assessment methods correlated strongly (r = 0.87, p < 0.0001) and showed minimal bias (1.05%). Correlation with MultiplateÂź was slightly higher for the flow cytometry‐based VASP assay (r = 0.79, p < 0.0001) than for the ELISA‐based assay (r = 0.69, p < 0.0001). Intraclass correlation (ICC) was moderate for all the assays tested (ICC between 0.62 and 0.84). However, categorization into low, optimal, or high platelet reactivity based on these assays was strongly concordant (Îș between 0.86 and 0.92). In conclusion, the consensus‐recommended assays with their standardized cut‐offs should not be used interchangeably in multi‐center clinical studies but, rather, they should be standardized throughout sites

    Emergence of winner-takes-all connectivity paths in random nanowire networks

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    Nanowire networks are promising memristive architectures for neuromorphic applications due to their connectivity and neurosynaptic-like behaviours. Here, we demonstrate a self-similar scaling of the conductance of networks and the junctions that comprise them. We show this behavior is an emergent property of any junction-dominated network. A particular class of junctions naturally leads to the emergence of conductance plateaus and a “winner-takes-all” conducting path that spans the entire network, and which we show corresponds to the lowest-energy connectivity path. The memory stored in the conductance state is distributed across the network but encoded in specific connectivity pathways, similar to that found in biological systems. These results are expected to have important implications for development of neuromorphic devices based on reservoir computing

    Proteomics-based identification of differentially abundant proteins reveals adaptation mechanisms of Xanthomonas citri subsp citri during Citrus sinensis infection

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    Background: Xanthomonas citri subsp. citri (Xac) is the causal agent of citrus canker. A proteomic analysis under in planta infectious and non-infectious conditions was conducted in order to increase our knowledge about the adaptive process of Xac during infection. Results: For that, a 2D-based proteomic analysis of Xac at 1, 3 and 5 days after inoculation, in comparison to Xac growth in NB media was carried out and followed by MALDI-TOF-TOF identification of 124 unique differentially abundant proteins. Among them, 79 correspond to up-regulated proteins in at least one of the three stages of infection. Our results indicate an important role of proteins related to biofilm synthesis, lipopolysaccharides biosynthesis, and iron uptake and metabolism as possible modulators of plant innate immunity, and revealed an intricate network of proteins involved in reactive oxygen species adaptation during Plants'Oxidative Burst response. We also identified proteins previously unknown to be involved in Xac-Citrus interaction, including the hypothetical protein XAC3981. A mutant strain for this gene has proved to be non-pathogenic in respect to classical symptoms of citrus canker induced in compatible plants. Conclusions: This is the first time that a protein repertoire is shown to be active and working in an integrated manner during the infection process in a compatible host, pointing to an elaborate mechanism for adaptation of Xac once inside the plant.Fundacao de Amparo a Pesquisa do Estado de Sao PauloFundacao de Amparo a Pesquisa do Estado de Minas GeraisBIGA grant-CAPESUniv Fed Ouro Preto, Inst Ciencias Exatas & Biol, Dept Ciencias Biol DECBI, Ouro Preto, MG, BrazilUniv Fed Ouro Preto, Nucleo Pesquisas Ciencias Biol NUPEB, Ouro Preto, MG, BrazilUniv Fed Rio de Janeiro, Inst Quim, Dept Bioquim DBq, Rio De Janeiro, RJ, BrazilUniv Estadual Paulista, UNESP, Dept Tecnol, Fac Ciencias Agr & Vet Jaboticabal, Jaboticabal, SP, BrazilUniv Estadual Campinas, UNICAMP, Inst Quim, Campinas, SP, BrazilUniv Sao Paulo, Inst Quim, Dept Bioquim, Sao Paulo, SP, BrazilUniv Fed Sao Paulo UNIFESP, Dept Ciencias Biol, Diadema, SP, BrazilVirginia Tech, Biocomplex Inst, Blacksburg, VA USAUniv Sao Paulo, Inst Quim, Dept Bioquim, Sao Paulo, SP, BrazilUniv Fed Sao Paulo UNIFESP, Dept Ciencias Biol, Diadema, SP, BrazilCAPESFAPESP: 04/02006-7Fundacao de Amparo a Pesquisa do Estado de Minas Gerais: CBB-APQ-04425-10BIGA grant-CAPES: 3385/2013Web of Scienc

    Mapping and assessment of ecosystems and their services. Urban ecosystems

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    Action 5 of the EU Biodiversity Strategy to 2020 requires member states to Map and Assess the state of Ecosystems and their Services (MAES). This report provides guidance for mapping and assessment of urban ecosystems. The MAES urban pilot is a collaboration between the European Commission, the European Environment Agency, volunteering Member States and cities, and stakeholders. Its ultimate goal is to deliver a knowledge base for policy and management of urban ecosystems by analysing urban green infrastructure, condition of urban ecosystems and ecosystem services. This report presents guidance for mapping urban ecosystems and includes an indicator framework to assess the condition of urban ecosystems and urban ecosystem services. The scientific framework of mapping and assessment is designed to support in particular urban planning policy and policy on green infrastructure at urban, metropolitan and regional scales. The results are based on the following different sources of information: a literature survey of 54 scientific articles, an online-survey (on urban ecosystems, related policies and planning instruments and with participation of 42 cities), ten case studies (Portugal: Cascais, Oeiras, Lisbon; Italy: Padua, Trento, Rome; The Netherlands: Utrecht; Poland: PoznaƄ; Spain: Barcelona; Norway: Oslo), and a two-day expert workshop. The case studies constituted the core of the MAES urban pilot. They provided real examples and applications of how mapping and assessment can be organized to support policy; on top, they provided the necessary expertise to select a set of final indicators for condition and ecosystem services. Urban ecosystems or cities are defined here as socio-ecological systems which are composed of green infrastructure and built infrastructure. Urban green infrastructure (GI) is understood in this report as the multi-functional network of urban green spaces situated within the boundary of the urban ecosystem. Urban green spaces are the structural components of urban GI. This study has shown that there is a large scope for urban ecosystem assessments. Firstly, urban policies increasingly use urban green infrastructure and nature-based solutions in their planning process. Secondly, an increasing amount of data at multiple spatial scales is becoming available to support these policies, to provide a baseline, and to compare or benchmark cities with respect to the extent and management of the urban ecosystem. Concrete examples are given on how to delineate urban ecosystems, how to choose an appropriate spatial scale, and how to map urban ecosystems based on a combination of national or European datasets (including Urban Atlas) and locally collected information (e.g., location of trees). Also examples of typologies for urban green spaces are presented. This report presents an indicator framework which is composed of indicators to assess for urban ecosystem condition and for urban ecosystem services. These are the result of a rigorous selection process and ensure consistent mapping and assessment across Europe. The MAES urban pilot will continue with work on the interface between research and policy. The framework presented in this report needs to be tested and validated across Europe, e.g. on its applicability at city scale, on how far the methodology for measuring ecosystem condition and ecosystem service delivery in urban areas can be used to assess urban green infrastructure and nature-based solutions

    Constraining the dark energy dynamics with the cosmic microwave background bispectrum

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    We consider the influence of the dark energy dynamics at the onset of cosmic acceleration on the Cosmic Microwave Background (CMB) bispectrum, through the weak lensing effect induced by structure formation. We study the line of sight behavior of the contribution to the bispectrum signal at a given angular multipole ll: we show that it is non-zero in a narrow interval centered at a redshift zz satisfying the relation l/r(z)≃kNL(z)l/r(z)\simeq k_{NL}(z), where the wavenumber corresponds to the scale entering the non-linear phase, and rr is the cosmological comoving distance. The relevant redshift interval is in the range 0.1\lsim z\lsim 2 for multipoles 1000\gsim\ell\gsim 100; the signal amplitude, reflecting the perturbation dynamics, is a function of the cosmological expansion rate at those epochs, probing the dark energy equation of state redshift dependence independently on its present value. We provide a worked example by considering tracking inverse power law and SUGRA Quintessence scenarios, having sensibly different redshift dynamics and respecting all the present observational constraints. For scenarios having the same present equation of state, we find that the effect described above induces a projection feature which makes the bispectra shifted by several tens of multipoles, about 10 times more than the corresponding effect on the ordinary CMB angular power spectrum.Comment: 15 pages, 7 figures, matching version accepted by Physical Review D, one figure improve

    Fucosylated Chondroitin Sulfate Inhibits Plasmodium Falciparum Cytoadhesion And Merozoite Invasion.

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    Sequestration of Plasmodium falciparum-infected erythrocytes (Pf-iEs) in the microvasculature of vital organs plays a key role in the pathogenesis of life-threatening malaria complications, such as cerebral malaria and malaria in pregnancy. This phenomenon is marked by the cytoadhesion of Pf-iEs to host receptors on the surfaces of endothelial cells, on noninfected erythrocytes, and in the placental trophoblast; therefore, these sites are potential targets for antiadhesion therapies. In this context, glycosaminoglycans (GAGs), including heparin, have shown the ability to inhibit Pf-iE cytoadherence and growth. Nevertheless, the use of heparin was discontinued due to serious side effects, such as bleeding. Other GAG-based therapies were hampered due to the potential risk of contamination with prions and viruses, as some GAGs are isolated from mammals. In this context, we investigated the effects and mechanism of action of fucosylated chondroitin sulfate (FucCS), a unique and highly sulfated GAG isolated from the sea cucumber, with respect to P. falciparum cytoadhesion and development. FucCS was effective in inhibiting the cytoadherence of Pf-iEs to human lung endothelial cells and placenta cryosections under static and flow conditions. Removal of the sulfated fucose branches of the FucCS structure virtually abolished the inhibitory effects of FucCS. Importantly, FucCS rapidly disrupted rosettes at high levels, and it was also able to block parasite development by interfering with merozoite invasion. Collectively, these findings highlight the potential of FucCS as a candidate for adjunct therapy against severe malaria.581862-7
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