286 research outputs found

    Generating and measuring the anisotropic elastic behaviour of Co thin films with oriented surface nano-strings on micro-cantilevers

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    In this research, the elastic behaviour of two Co thin films simultaneously deposited in an off-normal angle method was studied. Towards this end, two Si micro-cantilevers were simultaneously coated using pulsed laser deposition at an oblique angle, creating a Co nano-string surface morphology with a predetermined orientation. The selected position of each micro-cantilever during the coating process created longitudinal or transverse nano-strings. The anisotropic elastic behaviour of these Co films was determined by measuring the changes that took place in the resonant frequency of each micro-cantilever after this process of creating differently oriented plasma coatings had been completed. This differential procedure allowed us to determine the difference between the Young's modulus of the different films based on the different direction of the nano-strings. This difference was determined to be, at least, the 20% of the Young's modulus of the bulk Co

    Straining Flow Spinning of Artificial Silk Fibers: A Review

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    This work summarizes the main principles and some of the most significant results of straining flow spinning (SFS), a technology developed originally by the authors of this work. The principles on which the technology is based, inspired by the natural spinning system of silkworms and spiders, are presented, as well as some of the main achievements of the technique. Among these achievements, spinning under environmentally friendly conditions, obtaining high-performance fibers, and imparting the fibers with emerging properties such as supercontraction are discussed. Consequently, SFS appears as an efficient process that may represent one of the first realizations of a biomimetic technology with a significant impact at the production level.Ministerio de Economía y Competitividad MAT2016-75544-C2-1-RMinisterio de Economía y Competitividad MAT2016-79832-RMinisterio de Economía y Competitividad CPI2016-78887-C3-1-RComunidad de Madrid NEUROCENTRO-B2017Comunidad de Madrid BMD-376

    Spider silk gut: Development and characterization of a novel strong spider silk fiber

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    Spider silk fibers were produced through an alternative processing route that differs widely from natural spinning. The process follows a procedure traditionally used to obtain fibers directly from the glands of silkworms and requires exposure to an acid environment and subsequent stretching. The microstructure and mechanical behavior of the so-called spider silk gut fibers can be tailored to concur with those observed in naturally spun spider silk, except for effects related with the much larger cross-sectional area of the former. In particular spider silk gut has a proper ground state to which the material can revert independently from its previous loading history by supercontraction. A larger cross-sectional area implies that spider silk gut outperforms the natural material in terms of the loads that the fiber can sustain. This property suggests that it could substitute conventional spider silk fibers in some intended uses, such as sutures and scaffolds in tissue engineering.Ministerio de Economía y Competitividad (España) MAT2012-38412-C02-01Fondo Nacional de Ciencias Naturales de China 31160420, 31060282, 30760041Programa de Formación de Jóvenes Científicos (JingGang Star) 20133BCB2302

    Development of the (d,n) proton-transfer reaction in inverse kinematics for structure studies

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    Transfer reactions have provided exciting opportunities to study the structure of exotic nuclei and are often used to inform studies relating to nucleosynthesis and applications. In order to benefit from these reactions and their application to rare ion beams (RIBs) it is necessary to develop the tools and techniques to perform and analyze the data from reactions performed in inverse kinematics, that is with targets of light nuclei and heavier beams. We are continuing to expand the transfer reaction toolbox in preparation for the next generation of facilities, such as the Facility for Rare Ion Beams (FRIB), which is scheduled for completion in 2022. An important step in this process is to perform the (d,n) reaction in inverse kinematics, with analyses that include Q-value spectra and differential cross sections. In this way, proton-transfer reactions can be placed on the same level as the more commonly used neutron-transfer reactions, such as (d,p), (9Be,8Be), and (13C,12C). Here we present an overview of the techniques used in (d,p) and (d,n), and some recent data from (d,n) reactions in inverse kinematics using stable beams of 12C and 16O.Comment: 9 pages, 4 figures, presented at the XXXV Mazurian Lakes Conference on Physics, Piaski, Polan

    Improved Limit on Direct α Decay of the Hoyle State

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    The current evaluation of the triple-α reaction rate assumes that the α decay of the 7.65 MeV, 0+ state in 12C, commonly known as the Hoyle state, proceeds sequentially via the ground state of 8Be. This assumption is challenged by the recent identification of two direct α-decay branches with a combined branching ratio of 17(5)%. If correct, this would imply a corresponding reduction in the triple-α reaction rate with important astrophysical consequences. We have used the 11B(3He,d) reaction to populate the Hoyle state and measured the decay to three α particles in complete kinematics. We find no evidence for direct α-decay branches, and hence our data do not support a revision of the triple-α reaction rate. We obtain an upper limit of 5×10-3 on the direct α decay of the Hoyle state at 95% C.L., which is 1 order of magnitude better than a previous upper limit

    Patología neurológica en una unidad de cuidados intensivos pediátricos de tercer nivel. Evolución funcional. Nuestra experiencia

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    Introducción La enfermedad neurológica representa una parte importante en las unidades de cuidados intensivos pediátricos (UCIP) y es causa de morbimortalidad. El objetivo de este trabajo es analizar la evolución funcional del niño crítico con enfermedad neurológica. Material y método Estudio retrospectivo descriptivo, de niños con enfermedad neurológica ingresados en una UCIP durante 3 años (2012-2014), valorando pronóstico vital y funcional, al alta y al año del ingreso, según las Categorías de estado general y cerebral pediátrico (CEGP-CECP) y la Escala de estado funcional (FSS). Los resultados se comparan con nuestros datos previos (años 1990-1999) y con los del estudio multicéntrico internacional PANGEA. Resultados Se estudió a 266 niños. La mortalidad fue del 3%, sin que los modelos PRISM-II y PIM2 muestren capacidad predictiva. La salud funcional refleja empeoramiento clínicamente significativo al alta de UCIP, en el 30% según CEGP, en el 15% según CECP y en el 5% según FSS. Transcurrido un año, la funcionalidad mejora según CEGP-CECP, pero no según FSS. Los niños sin enfermedad neurológica de base presentan afectación funcional en mayor porcentaje, que se mantiene en el tiempo. Comparada con nuestros datos previos, la mortalidad global y neurocrítica disminuye (5, 60 vs. 2, 1%; p = 0, 0003 y 8, 44 vs. 2, 63%; p = 0, 0014, respectivamente). En relación con el estudio multicéntrico PANGEA, tanto la mortalidad como el empeoramiento funcional cerebral del niño neurocrítico son menores en el estudio actual (1, 05 vs. 13, 32%; p < 0, 0001 y 10, 47 vs. 23, 79%; p < 0, 0001, respectivamente). Conclusiones Alrededor de un tercio de los niños críticos muestran enfermedad neurológica. Un porcentaje importante, sobre todo de niños sin enfermedad neurológica basal, presenta repercusión funcional clínicamente significativa al alta de UCIP y transcurrido un año. La repercusión en el pronóstico funcional del niño crítico apoya la importancia de la neuromonitorización y neuroprotección, medidas necesarias para mejorar la asistencia del niño crítico y la valoración evolutiva de la salud funcional

    Experimental study of the β decay of the very neutron-rich nucleus Ge 85

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    The β-decay properties of the very neutron-rich nucleus Ge85, produced in the proton-induced fission of U238, were studied at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The level scheme of As523385 populated in Ge85βγ decay was reconstructed and compared to shell-model calculations. The investigation of the systematics of low-energy levels in N=52 isotones together with shell-model analysis allowed us to provide an estimate of the low-energy structure of the more exotic N=52 isotone Cu81
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