221 research outputs found

    Imaging the Kirkendall effect in pyrite (FeS2) thin films: cross-sectional microstructure and chemical features

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    This investigation provides novel data on the structure and chemical composition of pyrite thin films and new hints concerning their formation mechanism. From TEM-HAADF data, it has been found that the films are composed of two different layers: one is very compact and the other one is quite porous with many voids separating a few groups of grains. This porous layer is always in direct contact with the substrate, and its thickness is quite similar to that of the original Fe film. The average size of pyrite grains is equal in both layers, what suggests that the same process is responsible for their formation. Concentration profiles of sulfur, iron and some impurities (mainly sodium and oxygen from the glass substrate) through both layers are given in this work, and thus chemical inhomogeneities of the films are proved by the obtained stoichiometric ratios (S/Fe). Moreover, Na from sodalime glass substrates mainly accumulates at the pyrite grain boundaries and barely dopes them. The obtained results support the hypothesis that the iron sulfuration process essentially induces the diffusion of iron atoms, what leads to the porous layer formation as a manifestation of the Kirkendall Effect. Therefore, it seems that the same mechanisms that operate in the synthesis of surface hollow structures at the nanoscale are also active in the formation of pyrite thin films ranging from several tens to hundreds of nanometersMembers of MIRE Group acknowledge the financial support of the Spanish MICINN under project RTI2018-099794-B-I00. E. Flores acknowledges the intramural CSIC project 2D-MeSes funding and the service from the MiNa Laboratory at IMN, and funding from CM (project SpaceTec, S2013/ICE2822), MINECO (project CSIC13-4E1794) and EU (FEDER,FSE). Financial support through the project UMA18-FEDERJA-041 is gratefully acknowledge

    ExtracciĂłn secuencial de metales pesados en dos suelos contaminados (Andisol y Vertisol) enmendados con ĂĄcidos hĂşmicos

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    En suelos Andisoles y Vertisoles, bajo condiciones controladas, se evaluó el efecto de åcidos húmicos purificados en concentraciones de 0%, 2.5% y 5% (peso/peso)) sobre la extracción secuencial de metales pesados despuÊs de incubación a 60 y 90 días.  El fraccionamiento de los metales (Ni, Cu, Zn, Cd y Pb) en suelos contaminados y enmendados con åcidos húmicos se realizó mediante extracción secuencial de Tessier.  La movilidad de los metales se redujo con la adición de dichos åcidos, con mayor retención de Ni, Cu, Zn y Cd en la matriz del suelo (fracción residual).  El Pb en ambos suelos y el Zn en Vertisol experimentaron incremento significativo en su movilidad, mayor biodisponibilidad y potencial de afectación de diferentes componentes del medio-ambiente.  El incremento del tiempo de incubación permitió la interacción de los metales con los componentes de los suelos, generando disminución de su movilidad por mecanismos como formación de complejos estables y/o incremento de la capacidad de intercambio catiónico (CIC) de los suelos.  Los åcidos húmicos pueden ser utilizados, en general, como enmienda orgånica para la recuperación de suelos contaminados con metales pesados

    AdsorciĂłn de metales pesados en Andisoles, Vertisoles y ĂĄcidos hĂşmicos

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    La presente investigación estudió la adsorción de cinco metales pesados (Cd, Cu, Ni, Pb y Zn) en tres adsorbentes, dos suelos agrícolas colombianos (Typic Melanudand y Epiaquert ústico arcilloso fino isohipertÊrmico 1%) y åcidos húmicos (AH) extraídos de leonardita, de Espaùa, mediante la metodología descrita por Mosquera et al. (2007). A los suelos y a los AH se les determinaron propiedades químicas como pH, Capacidad de Intercambio Catiónico (CIC), carbono orgånico (%CO), bases intercambiables y contenido total de metales. La composición química de los AH se determinó empleando tÊcnicas espectromÊtricas como ICP_MS, FTIR, UV-Vis, CPMAS 13C NMR y Py-GC/MS-THMA. Los resultados de la adsorción de metales se ajustaron al modelo de Freundlich, y muestran un comportamiento disímil de los absorbentes en relación a los metales estudiados, es así como la måxima capacidad de adsorción (K) y la fuerza de retención (n) de los metales es significativamente diferente (pPbCuNiZn, Andisol: PbCuCdZnNi, y Vertisol: CdPbCuNiZn; y para n, Ácidos Húmicos: PbZnCdCuNi, Andisol: CuNiZnPbCd, y Vertisol: ZnNiCuPbCd.This research studied the adsorption of five heavy metals (Cd, Cu, Ni, Pb and Zn) in three adsorbents, two Colombian agricultural soils (Typic Melanudand and fine clay 1% isohyperthermic-Ustic Epiaquert) and humic acids (HA) extracted from leonardite, of Spain. In both, HA and soils, the chemical properties determined were: pH, cation exchange capacity (CEC), organic carbon (% OC), exchangeable bases and total content of metals. The hemical composition of HA was determined using spectrometric techniques as ICP_MS, FTIR, UV-Vis, and CPMAS 13C NMR and Py-GC/MS-THMA. The results from the adsorption of metals in the three adsorbents were adjusted to Freundlich model, and these show a different behavior of the absorbers relative to the metals studied, in the same way the maximum adsorption capacity (K) and the retention force (n) of metals is significantly different (p 0.05). According to K and n of each adsorbent, the adsorption selectivity sequences of the metals has the following order of preference for K: In Humic Acids: Cd Pb Cu Ni Zn, Andisol: Pb Cu Cd Zn Ni, and Vertisol: Cd Pb Cu Ni Zn. For n, Humic Acids: Pb Zn Cd Cu Ni, Andisol: Cu Ni Zn Pb Cd, and Vertisol: Zn Ni Cu Pb C

    Serum albumin level as a risk factor for mortality in burn patients

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    OBJECTIVE: Hypoalbuminemia is a common clinical deficiency in burn patients and is associated with complications related to increased extravascular fluid, including edema, abnormal healing, and susceptibility to sepsis. Some prognostic scales do not include biochemical parameters, whereas others consider them together with comorbidities. The purpose of this study was to determine whether serum albumin can predict mortality in burn patients. METHODS: We studied burn patients ≥16 years of age who had complete clinical documentation, including the Abbreviated Burn Severity Index, serum albumin, globulin, and lipids. Sensitivity and specificity analyses were performed to determine the cut-off level of albumin that predicts mortality. RESULTS: In our analysis of 486 patients, we found that mortality was higher for burns caused by flame (p = 0.000), full-thickness burns (p = 0.004), inhalation injuries (p = 0.000), burns affecting >;30% of the body surface area (p = 0.001), and burns associated with infection (p = 0.008). Protein and lipid levels were lower in the patients who died (

    DPYD pathogenic variants associated with fluoropyrimidines toxicity

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    Background: Genetic variants in dihydropyrimidine dehydrogenase gene (DPYD) coding for the key enzyme (DPD) of fluoropyrimidines (FPs) catabolism. DPYD contributes to the development of severe FPs-related toxicity, and pathogenic DPYD variants detection reduces side effects and complications associated with FP-toxicity. The allelic frequency of these variants in the Mexican population is currently unknown. Methods: The study was carried out at the Centro Universitario Contra el CĂĄncer (CUCC) of the Universidad AutĂłnoma de Nuevo LeĂłn (UANL) in Monterrey MĂŠxico. Genomic DNA was isolated from 154 subjects using the QIAamp DNA Blood Midi kit (QIAGEN) following the manufacturer\u27s recommendations. We analyze the variants c.1156G-\u3eT, c.2846A-\u3eT, and c.1129-5923C-\u3eG by qPCR using predesigned probes. For the remaining genomic variants (c.1905+1G-\u3eA, c.1679T-\u3eG, c.1898delC and c.299_302delTCAT), we design sequencing oligos using the software Oligo Primer v.7ÂŽ. The allele frequency was calculated for each variant. Results: We analyzed a total of 154 samples to detect the seven variants analyzed. So far, only 2 samples have been found that presented the variant c.1129-5923C\u3eG in a state of heterozygosis, representing 1.2987% of the total of our population. Conclusions: The allele frequency for the variant c.1129-5923C-\u3eG was higher than reported in other populations. So this allele is more common in our population, which could attribute to the large percentage of side effects in our patients. However, more studies and increasing the number of samples are needed to establish DPYD the allele frequency more precisely

    Initial CONNECT Architecture

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    Interoperability remains a fundamental challenge when connecting heterogeneous systems which encounter and spontaneously communicate with one another in pervasive computing environments. This challenge is exasperated by the highly heterogeneous technologies employed by each of the interacting parties, i.e., in terms of hardware, operating system, middleware protocols, and application protocols. The key aim of the CONNECT project is to drop this heterogeneity barrier and achieve universal interoperability. Here we report on the development of the overall CONNECT architecture that will underpin this solution; in this respect, we present the following contributions: i) an elicitation of interoperability requirements from a set of pervasive computing scenarios, ii) a survey of existing solutions to interoperability, iii) an initial view of the CONNECT architecture, and iv) a series of experiments to provide initial validation of the architecture

    Mejoramiento del parque Juan Aldama - AutoconstrucciĂłn de techo verde de bambĂş en vivienda social, Puerto Vallarta, Jalisco

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    El proyecto Regeneración socioambiental del río Pitillal en Puerto Vallarta, ha sido desarrollado por los equipos del PAP desde la primavera de 2021 y contempla una metodología que combina la producción social del hábitat (Ortiz. E, 2012) con la autoconstrucción con materiales locales (Comunal, 2019). Se han desarrollado investigaciones para generar diagnósticos, posteriormente se han desarrollados propuestas técnicas que se han validado con los habitantes de la zona. Se busca actualmente pasar a la etapa de la acción participativa, buscando motivar el involucramiento de los actores locales y beneficiarios de las zonas en las que se da el acompañamiento. Se presenta aquí el reporte del proceso de la realización de dos líneas de investigación que dan continuidad a procesos que se originaron en semestres anteriores del PAP en el escenario de Puerto Vallarta:AUTOCONSTRUCCIÓN DE CUBIERTA DE BAMBÚ Y FORESTACIÓN EN PARQUE JUAN ALDAMA y AUTOCONSTRUCCIÓN DE CUBIERTA DE BAMBÚ Y FORESTACIÓN EN AZOTEA DE VIVIENDA EN VALLARTA VILLAS.ITESO, A.C

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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