2,511 research outputs found

    Surface plasmon resonance screening of synthetic peptides mimicking the immunodominant region of C-S8c1 foot-and-mouth disease virus

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    The main antigenic site (site A) of foot-and-mouth disease virus (FMDV, strain C-S8c1) may be adequately reproduced by a 15-peptide with the amino acid sequence H-YTASARGDLAHLTTT-NH2 (A15), corresponding to the residues 136-150 of the viral protein VPI. The effect of amino acid substitutions within A15 on its antigenicity towards monoclonal antibodies (MAb) raised against antigenic site A, has been studied by means of BIAcore technology, based on surface plasmon resonance (SPR). Although these antigenicities have previously been determined from enzyme-linked immunosorbent assays (ELISA), the SPR-based technique is superior in that it allows a fast and straightforward screening of antigens while simultaneously providing kinetic data of the antigen-antibody interaction. With a view to screening fairly large libraries of individual peptides, we have inverted the typical SPR experiment by immobilizing the MAb on the sensor surface and using peptides as soluble analytes. We report the validation of this approach through the screening of 44 site A peptides, with results generally in good agreement with the relative antigenicities previously determined by competition ELISA

    Molecular analysis of peptides from the GH loop of foot-and-mouth disease virus C-S30 using surface plasmon resonance: a role for kinetic rate constants

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    A foot-and-mouth disease virus (FMDV) field variant, isolate C-S30 (also named C-1-Barcelona), is known to contain four changes within the main antigenic site A (GH loop of capsid protein VP1, residues 136-150), at least one of which (Leu147 --> Val) involves a highly conserved position, critical for antibody recognition in the reference strain C-S8c1. However, immunoenzymatic analysis of FMDV C-S30 showed it was recognised by 4C4, a monoclonal antibody that specifically targets site A. This remarkable behaviour has led us to analyse the individual and combined contributions of the four mutations to the antigenicity of C-S30, by surface plasmon resonance (SPR) and enzyme-linked immunosorbent assay (ELISA) studies of pentadecapeptides displaying all possible combinations of the four replacements. Analysis of this family of C-S30-derived analogues shows a certain level of antibody recognition by SPR. In addition, SPR data suggest that kinetic rate constants provide an indirect measure, on the one hand, of paratope accessibility (association rate constant) and, on the other hand, of peptide fitness to the same paratope (dissociation rate constant)

    Broadband distortion modeling in Lyman-α\alpha forest BAO fitting

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    In recent years, the Lyman-α\alpha absorption observed in the spectra of high-redshift quasars has been used as a tracer of large-scale structure by means of the three-dimensional Lyman-α\alpha forest auto-correlation function at redshift z2.3z\simeq 2.3, but the need to fit the quasar continuum in every absorption spectrum introduces a broadband distortion that is difficult to correct and causes a systematic error for measuring any broadband properties. We describe a kk-space model for this broadband distortion based on a multiplicative correction to the power spectrum of the transmitted flux fraction that suppresses power on scales corresponding to the typical length of a Lyman-α\alpha forest spectrum. Implementing the distortion model in fits for the baryon acoustic oscillation (BAO) peak position in the Lyman-α\alpha forest auto-correlation, we find that the fitting method recovers the input values of the linear bias parameter bFb_{F} and the redshift-space distortion parameter βF\beta_{F} for mock data sets with a systematic error of less than 0.5\%. Applied to the auto-correlation measured for BOSS Data Release 11, our method improves on the previous treatment of broadband distortions in BAO fitting by providing a better fit to the data using fewer parameters and reducing the statistical errors on βF\beta_{F} and the combination bF(1+βF)b_{F}(1+\beta_{F}) by more than a factor of seven. The measured values at redshift z=2.3z=2.3 are $\beta_{F}=1.39^{+0.11\ +0.24\ +0.38}_{-0.10\ -0.19\ -0.28}and and b_{F}(1+\beta_{F})=-0.374^{+0.007\ +0.013\ +0.020}_{-0.007\ -0.014\ -0.022}(1 (1\sigma,2, 2\sigmaand3 and 3\sigma$ statistical errors). Our fitting software and the input files needed to reproduce our main results are publicly available.Comment: 28 pages, 15 figures, matches the published versio

    The convergence between sustainability and conventional stock indices. Are we on the right track?

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    The growth of passive and socially responsible (SR) investment makes that sustainability indices play an important role in defining what constitutes a sustainable investment. In order to know the suitability of sustainability indices as benchmarks for SR investors, we used different linear regressions to compare the compositions of sustainability indices and their conventional counterparts and to compare the levels of corporate social responsibility (CSR) of both types of indices. We showed that the composition of sustainability indices gradually converged towards their conventional peers. Moreover, the difference between the CSR levels of both type of indices remained the same or even decreased over time. We concluded that a change in the weighting method of sustainability indices such as the equally weighted criterion would significantly increase the difference from their conventional counterparts. However, due to the relationship between CSR and size, this change would penalize the CSR level of the index. These results raise the question of whether SR passive investors will be able to meet their non-financial expectations as a consequence of the convergence. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

    A caricature of a singular curvature flow in the plane

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    We study a singular parabolic equation of the total variation type in one dimension. The problem is a simplification of the singular curvature flow. We show existence and uniqueness of weak solutions. We also prove existence of weak solutions to the semi-discretization of the problem as well as convergence of the approximating sequences. The semi-discretization shows that facets must form. For a class of initial data we are able to study in details the facet formation and interactions and their asymptotic behavior. We notice that our qualitative results may be interpreted with the help of a special composition of multivalued operators

    Super-Nernstian Shifts of Interfacial Proton-Coupled Electron Transfers : Origin and Effect of Noncovalent Interactions

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    The support of the University of Aberdeen is gratefully acknowledged. C.W. acknowledges a summer studentship from the Carnegie Trust for the Universities of Scotland. E.P.M.L. acknowledges SeCYT (Universidad Nacional de Cordoba), ́ CONICET- PIP 11220110100992, Program BID (PICT 2012-2324), and PME 2006-01581 for financial support.Peer reviewedPostprin

    Modelling magnetic flux emergence in the solar convection zone

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    [Abridged] Bipolar magnetic regions are formed when loops of magnetic flux emerge at the solar photosphere. Our aim is to investigate the flux emergence process in a simulation of granular convection. In particular we aim to determine the circumstances under which magnetic buoyancy enhances the flux emergence rate (which is otherwise driven solely by the convective upflows). We use three-dimensional numerical simulations, solving the equations of compressible magnetohydrodynamics in a horizontally-periodic Cartesian domain. A horizontal magnetic flux tube is inserted into fully developed hydrodynamic convection. We systematically vary the initial field strength, the tube thickness, the initial entropy distribution along the tube axis and the magnetic Reynolds number. Focusing upon the low magnetic Prandtl number regime (Pm<1) at moderate magnetic Reynolds number, we find that the flux tube is always susceptible to convective disruption to some extent. However, stronger flux tubes tend to maintain their structure more effectively than weaker ones. Magnetic buoyancy does enhance the flux emergence rates in the strongest initial field cases, and this enhancement becomes more pronounced when we increase the width of the flux tube. This is also the case at higher magnetic Reynolds numbers, although the flux emergence rates are generally lower in these less dissipative simulations because the convective disruption of the flux tube is much more effective in these cases. These simulations seem to be relatively insensitive to the precise choice of initial conditions: for a given flow, the evolution of the flux tube is determined primarily by the initial magnetic field distribution and the magnetic Reynolds number.Comment: 12 pages, 15 figures, 2 tables. Accepted for publication in Astronomy and Astrophysic

    Recuperación e identificación de variedades de vid en Aragón

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    1 copia .pdf del Póster original de los Autores.- 1 Tabl.- 4 Fots. Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)A partir de la década de los setenta diferentes circunstancias provocaron que muchas de las zonas más productivas arrancaran las vides antiguas y apostaran por plantaciones de variedades foráneas o distintas de las tradicionales. Conscientes de la pérdida de biodiversidad, desde la Unidad de Tecnología Vegetal (Gobierno de Aragón) se viene prospectando en toda la geografía aragonesa y recopilando accesiones de vid, especialmente en viñas antiguas y a punto de desaparecer. El año 1992 se formó el Banco de Germoplasma de Vid de Aragón (Dep. de Agricultura, Ganadería y Medio Ambiente) que conserva más de 700 accesiones (algunas caracterizadas molecularmente, Buhner-Zaharieva et al., 2010) .Este trabajo ha sido financiado por el INIA (RF2012-00027-C05-02) y el Gobierno de Aragón (A44)Peer reviewe

    Towards three-dimensional non-invasive recording of incised rock art

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    Ancient art cut into rock is difficult to research and manage off-site without precise three-dimensional records. Experiments with photographic modelling by the authors led to a relatively accessible and economical way of making them
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