545 research outputs found

    UV- and visible-light photocatalysis using Ni–Co bimetallic and monometallic hydrotalcite-like materials for enhanced CO2 methanation in sabatier reaction

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    The CO2 catalytic reduction activities of four different Co-modified Ni-based catalysts derived from hydrotalcite-like materials (HTCs) prepared by co-precipitation method were investigated under thermal and photocatalytic conditions. All catalysts were tested from 473 to 723 K at 10 bar (abs). The light intensity for photocatalytic reactions was 2.4 W cm-2. The samples were characterized to determine the effect of morphological and physicochemical properties of mono-bimetallic active phases on their methanation activity. The activity toward CO2 methanation followed the next order: Ni > Co–Ni > Co. For the monometallic Ni catalyst an increase of a 72% was achieved in the photo-catalytic activity under UV and vis light irradiation at temperatures lower by > 100 K than those in a conventional reaction. Co-modified Ni based hydrotalcite catalysts performed with stability and no deactivation for the 16 h studied under visible light for methanation at 523 K due to the presence of basic sites.This research was supported by: Basque Government Project: IT1554-22 and University of the Basque Country. Grant PID2020-112889RB-I00 funded by: MCIN/AEI/10.13039/501100011033. Authors are grateful for the support provided: SGIker/UPV/EHU & European funding (ERDF and ESF)

    Influence of Zn excess on compositional, structural and vibrational properties of Cu2ZnSn0.5Ge0.5Se4 thin films and their effect on solar cell efficiency

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    This Accepted Manuscript will be available for reuse under a CC BY-NC-ND licence after 24 months of embargo periodThe effect of Zn content on compositional, structural and vibrational properties of Cu2ZnSn1-xGexSe4 (CZTGSe, x ~ 0.5) thin films is studied. Kesterite layer is deposited by co-evaporation onto 5 × 5 cm2 Mo/SLG substrate followed by a thermal treatment at maximum temperature of 480 °C, obtaining areas with different composition and morphology which are due to the sample position in the co-evaporation system and to the non-uniform temperature distribution across the substrate. Kesterite layers with higher Zn amounts are characterized by lower Cu and Ge contents; however, a uniform Ge distribution through the absorber layer is detected in all cases. The excess Zn concentration leads to the formation of ZnSe secondary phase on the surface and in the bulk of the absorber as determined by Raman spectroscopy. When higher Ge content and no ZnSe are present in the absorber layer, a compact structure is formed with larger grain size of kesterite. This effect could explain the higher Voc of the solar cell. The Zn content does not affect the bandgap energy significantly (Eg near 1.3 eV), although the observed effect of Zn excess in CZTGSe results in a decreased device performance from 6.4 to 4.2%. This investigation reveals the importance of the control of the off-stoichiometric CZTGSe composition during the deposition process to enhance solar cells propertiesThis work was supported by Spanish Ministry of Science, Innovation and Universities Project WINCOST (ENE2016-80788-C5-2-R) and European Project INFINITE CELL (H2020-MSCA-RISE-2017-777968). ARP also acknowledges financial support from Community of Madrid within Youth Employment Program (PEJD-2017-PRE/IND-4062). MG acknowledges the financial support from ACCIÓ-Generalitat de Catalunya within the TECNIOspring Plus fellowship (TECSPR18-1-0048

    Convergencia de la dispersión salarial en España

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    El objetivo del trabajo es analizar si ha existido convergencia de la dispersión salarial durante el periodo 2008-2015 entre las comunidades autónomas españolas, tanto en un análisis global como en un análisis desagregado por género. Para ello se ha empleado la encuesta anual de estructura salarial (EAES) que proporciona datos sobre la distribución salarial en España. Con estos datos, se han calculado las dos medidas de dispersión salarial utilizadas, el recorrido intercuartílico y el recorrido interdecílico tanto en términos absolutos como en términos relativos. Con dichas medidas se han realizado diversas estimaciones para poder analizar la convergencia en la dispersión salarial utilizando las dos medidas de convergencia más utilizadas, β-convergencia (absoluta y condicionada), y la σ-convergencia. Con estas estimaciones, no se puede afirmar, de forma estricta, la existencia de convergencia en la dispersión salarial el periodo estudiado, ya que las comunidades autónomas convergen hacia distintos estados estacionarios.Grado en Administración y Dirección de Empresa

    A deep vein thrombosis caused by 20209C>T mutation in homozygosis of the prothrombin gene in a Caucasian patient

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    Introduction: Additional nucleotide substitutions in the 3 ´-untranslated region of prothrombin gene could explain some thrombotic events and also adverse pregnancy outcomes. We describe the first case of a homozygous 20209C>T mutation as the cause of deep vein thrombosis in a Spanish patient. Case and methods: The 56-year-old male patient with a partial tear of the Achilles tendon developed calf (tibial) deep vein thrombosis after im- mobilization and was treated with an anticoagulant. To determine if the deep vein thrombosis was of genetic origin, a peripheral blood DNA sample was analysed for the presence of the three most frequent mutations associated with thrombotic events: factor V Leiden (1691G>A), prothrombin (20210G>A) and methylene tetrahydrofolate reductase (677C>T). The presence or absence of the normal allele of prothrombin could not be deter- mined using the PTH-FV-MTHFR StripAssay (Vienna Lab). Results: Comprehensive analysis showed that the patient had a variant interfering with the polymerase chain reaction product, we sequenced the entire prothrombin gene and found that the patient had a homozygous C>T mutation at position 20209; this interfered with the polymerase chain reaction product, which needs a C at this position to be able to bind to the wild-type probe present in the test strip. Conclusion: The homozygous 20209C>T mutation and the presence of the mutation 677C>T in heterozygosity explained the patient’s deep vein thrombosis because the combination of mutations would increase the risk of thrombosis. Suitable genetic counselling should be provided to the pa- tient and first-degree relatives as it important to detect prothrombin gene variants that could increase risk for thrombotic events

    Raman microprobe characterization of electrodeposited S-rich CuIn(S,Se)2 for photovoltaic applications: Microstructural analysis

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    This article reports a detailed Raman scattering and microstructural characterization of S-rich CuIn(S,Se)2 absorbers produced by electrodeposition of nanocrystalline CuInSe2 precursors and subsequent reactive annealing under sulfurizing conditions. Surface and in-depth resolved Raman microprobe measurements have been correlated with the analysis of the layers by optical and scanning electron microscopy, x-ray diffraction, and in-depth Auger electron spectroscopy. This has allowed corroboration of the high crystalline quality of the sulfurized layers. The sulfurizing conditions used also lead to the formation of a relatively thick MoS2 intermediate layer between the absorber and the Mo back contact. The analysis of the absorbers has also allowed identification of the presence of In-rich secondary phases, which are likely related to the coexistence in the electrodeposited precursors of ordered vacancy compound domains with the main chalcopyrite phase, in spite of the Cu-rich conditions used in the growth. This points out the higher complexity of the electrodeposition and sulfurization processes in relation to those based in vacuum deposition techniques

    Síntesis de capas de SiC en substrato de Si mediante implantación iónica

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    En este trabajo se investiga la síntesis de estructuras SiC/Si mediante implantación iónica de carbono en Si. Las implantaciones se han realizado a energías entre 25 y 300 keV y las dosis en el rango lO^^ylO^^ cm , manteniendo el substrato a temperatura ambiente o 500°C. Algunas estructuras han sido recocidas a 1150°C. Los resultados indican que implantando a temperatura ambiente se forma una capa de SiC amorfa y de composición gradual, que recristaliza formando precipitados de ß-SiC con orientaciones aleatorias después del recocido. Además se forma un capa superficial rica en carbono, debida a la difusión del carbono hacia la superficie durante la implantación, y que desaparece con el recocido. Implantando a 500°C se forma directamente una capa con una muy alta densidad de precipitados de ß-SiC orientados preferencialmente con la matriz de silicio. Dada la estabilidad térmica y química de dicha capa se han realizado membranas de SiC mediante técnicas fotolitográficas y ataque químico selectivo, cuya rugosidad superficial es inferior a 6 nm. Estas membranas muestran unos gradientes de tensiones residuales, que prácticamente desaparecen después del recocido. Los resultados confirman la potencialidad de la implantación iónica para la formación de estructuras microme-cánicas de SiC sobre Si

    Zr-metal adhesion on graphenic nanostructures

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    3 pages, 3 figures.-- PACS nrs.: 68.35.Np, 61.46.Fg, 61.46.Df.Our high resolution transmission electronic microscopy studies of multiwall carbon nanotubes show, after the growth of zirconia nanoparticles by a hydrothermal route, the presence of surface Zr, forming an atomically thin layer. Using first-principles calculations we investigate the nature of the Zr–C interaction, which is neither ionic nor covalent, and the optimal coverage for the Zr metal in a graphene flake. This preferred coverage is in agreement with that deduced from electron energy loss spectra experiments. We show also that the amount of charge transferred to the C layer saturates as the Zr coverage increases and the Zr–C bond becomes weaker.We want to acknowledge the support by the ETORTEK (NANOMAT) program of the Basque government, the Intramural Special Project (Reference No. 2006601242), the Spanish Ministerio de Ciencia y Tecnología (MCyT) of Spain (Grant No. Fis 2007-66711-C02-C01), and the European Network of Excellence NANOQUANTA (NM4-CT-2004-500198). Y.S.P. gratefully acknowledges his DIPC grant.Peer reviewe

    Analysis of the isometric activation of the gluteus medius and the intrinsic musculature of the sole in the prevention of injuries in elite basketball players: a pilot study

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    [Resumen] Introducción: El valgo dinámico de rodilla es uno de los principales factores de riesgo de lesión de deportes de impacto como el Baloncesto. Mejorar los sistemas de análisis de identificación de los factores de riesgo y los protocolos de prevención de lesiones se ha convertido en uno de los objetivos principales del fisioterapeuta deportivo, con el objetivo de disminuir el riesgo de lesión del deportista. Material y Métodos: Se analizó la distribución de las presiones plantares y los ángulos de alineación de los segmentos corporales en el plano frontal durante el Single-Leg-Squat Test en 10 sujetos deportistas de élite, con el objetivo de y observar la modificación a corto plazo asociada a la activación isométrica del glúteo medio y la musculatura intrínseca de la planta del pie. Resultados: Variaciones significativas en el aumento de la presión plantar del primer metatarsiano se registraron tras la activación del glúteo medio y de la musculatura intrínseca del pie. No se obtuvieron resultados significativos en la modificación de los ángulos de alineación en el plano frontal. Conclusiones: Un aumento de la presión plantar de la cabeza del primer metatarsiano puede relacionarse con una mayor estabilidad del miembro, mediante la activación del glúteo medio y de la musculatura intrínseca del pie. Son necesarios estudios con muestras más amplias que correlacionen los datos obtenidos en una muestra más homogénea.[Abstract] Introduction: Dynamic knee valgus is one of the main injury risk factors of impact sports such as basketball. Systems improvement for the analysis of identification of risk factors and injury prevention protocols has become one of the main objectives of the sports physiotherapist, with the aim of reducing the risk of athletes injury. Material and Methods: The distribution of plantar pressures and the angles of alignment of the body segments in the frontal plane during the Single-Leg-Squat Test in 10 elite athletes was analyzed, with the objective of observing the modification in short-term associated with the isometric activation of the gluteus medius and the intrinsic plantar musculature of the foot. Results: Significant variations in the increase of plantar pressure of the first metatarsal were recorded after activation of the gluteus medius and the intrinsic plantar muscles of the foot. No significant results were obtained in the modification of the alignment angle in the frontal plane. Conclusions: An increase in the plantar pressure of the head of the first metatarsal can be related to greater stability of the limb, through activation of the gluteus medius and the intrinsic plantar muscles of the foot. Studies with larger samples that correlate the data obtained in a more homogeneous sample are necessary

    Perioperative management and early complications after intestinal resection with ileocolonic anastomosis in Crohn’s disease: analysis from the PRACTICROHN study

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    This study is aimed at describing the prevalence of and risk factors associated with early post-operative complications after Crohn’s disease-related intestinal resection. Methods: This was a retrospective analysis of data from the PRACTICROHN cohort. Adult Crohn’s disease patients who underwent ileocolonic resection with ileocolonic anastomosis between January 2007 and December 2010 were included. The complications evaluated included death, ileus, anastomotic leak, abscess, wound infection, catheter-related infection, digestive bleeding and other extra-abdominal infections that occurred in the 30 days after surgery.Results: A total of 364 patients (median age at surgery 38 years and 50% men) were included. Indication for surgery was: stricturing disease (46.4%), penetrating disease (31.3%), penetrating and stricturing disease (14.0%) or resistance to medical treatment (5.8%). Early complications were recorded in 100 (27.5%) patients, with wound infection, intra-abdominal abscess and anastomotic leakage being the most frequent complications. Median hospitalization duration was 16 days for patients with complications vs. 9 days without complications (P<0.001). Complications were more common among patients with penetrating disease (36/114, 31.6%) and those refractory to treatment (9/21, 42.9%) compared with stricturing disease (45/169, 26.6%) or stricturingþpenetrating disease (6/51, 11.8%) (P¼0.040). The rate of complications was higher among patients with diagnosis made at the time of surgery (15/31, 48.4%) compared with the rest (85/331, 25.7%) (P¼0.013). Medication received at the time of surgery did not affect the rate of complications. Conclusions: Almost a quarter of patients developed early complications after intestinal resection. Penetrating disease and urgent surgery were associated with an increased risk of complicationsThis study was supported by Merck Sharp and Dohme, Spai

    Resonant Raman scattering based approaches for the quantitative assessment of nanometric ZnMgO layers in high efficiency chalcogenide solar cells

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    This work reports a detailed resonant Raman scattering analysis of ZnMgO solid solution nanometric layers that are being developed for high efficiency chalcogenide solar cells. This includes layers with thicknesses below 100 nm and compositions corresponding to Zn/(Zn + Mg) content rations in the range between 0% and 30%. The vibrational characterization of the layers grown with different compositions and thicknesses has allowed deepening in the knowledge of the sensitivity of the different Raman spectral features on the characteristics of the layers, corroborating the viability of resonant Raman scattering based techniques for their non-destructive quantitative assessment. This has included a deeper analysis of different experimental approaches for the quantitative assessment of the layer thickness, based on (a) the analysis of the intensity of the ZnMgO main Raman peak; (b) the evaluation of the changes of the intensity of the main Raman peak from the subjacent layer located below the ZnMgO one; and (c) the study of the changes in the relative intensity of the first to second/third order ZnMgO peaks. In all these cases, the implications related to the presence of quantum confinement effects in the nanocrystalline layers grown with different thicknesses have been discussed and evaluated
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