Síntesis de perovsquitas basadas en La(1-x-y)SryMnO3+σ y nitruros del sistema W2N para su aplicación como electrodos en pilas de combustible de intercambio protónico de alta temperatura

Tesis doctoral inédita, leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Inorgánica. Fecha de lectura: 20-12-201

Doping, carriers and intergrain fields in ZnO films: An impedance and confocal Raman spectroscopy study

A detailed study of the effect of doping on the electrical transport characteristics of ZnO thin films is presented. This is performed for undoped ZnO and for ZnO doped with Al and Ga. The films have been characterized by conventional direct current, DC, Hall transport measurements, impedance spectroscopy, IS, and confocal Raman spectroscopy, CRS. The variation of the transport properties caused by doping is related to a variation of the built-in electric field at the grain boundaries. This variation is observed through a variation of confocal Raman spectroscopy localized bands that are related to structural ZnO defects. This technique allows one to measure the Raman spectra as electrical current is being fed to the film. The comparison between DC Hall transport measurements and impedance spectroscopy data confirms a semiconductor like behavior for ZnO and ZnO:Al and a metallic-like behavior of ZnO:Ga. This is due to the different amount of ions that enter substitutionally in the ZnO matrix and thus introduce carriers that compensate charge traps at the grain boundaries. The variation of this charge trap density and the associated electric field is probably the most relevant limiting factor of these films' transport properties. © 2013 Elsevier B.V. All rights reserved.The authors gratefully acknowledge funding by projects MAT2008-6330 and FUNCOAT-CSD2008-00023-CONSOLIDER INGENIO. This work was partially supported by the Sonderforschungsbereich under Grant No. SFB 762, “Functionality of Oxide Interfaces”.Peer Reviewe

Synthesis and characterization of tungsten nitride (W2N) from WO3 and H2WO4 to be used in the electrode of electrochemical devices

Tungsten nitride was synthesized from commercial WO3 and H2WO4, two precursors with different specific surface areas: 1.0 m2/g and 14.7 m2/g. The material was prepared by nitridation method by a thermal treatment at 873 K under NH3 flow. The W2N single phase was obtained with a crystal size of 15 nm and 11 nm, respectively, and with specific surface areas of 7.3 m2/g (from WO3) and 27.8 m2/g (from H2WO4). Both W2N exhibited high stability after a phosphoric acid attack. The W2N (WO3) powders show a high conductivity with a low activation energy (0.02 eV) measured by Electrochemical Impedance Spectroscopy. Those properties, that is, stability, high electronic conductivity and low activation energy make W2N a promising candidate to be used in the electrode of electrochemical devices in high corrosive environments.The authors are grateful for the financial support provided for Spanish projects ENE2009-14750-C05-03 and ENE2008-06888-C02-01, and European Community project NMP3-CT-033228.Peer Reviewe

MELD 3.0 adequately predicts mortality and renal replacement therapy requirements in patients with alcohol-associated hepatitis

Model for End-Stage Liver Disease (MELD) score better predicts mortality in alcohol-associated hepatitis (AH) but could underestimate severity in women and malnourished patients. Using a global cohort, we assessed the ability of the MELD 3.0 score to predict short-term mortality in AH. This was a retrospective cohort study of patients admitted to hospital with AH from 2009 to 2019. The main outcome was all-cause 30-day mortality. We compared the AUC using DeLong's method and also performed a time-dependent AUC with competing risks analysis. A total of 2,124 patients were included from 28 centres from 10 countries on three continents (median age 47.2 ± 11.2 years, 29.9% women, 71.3% with underlying cirrhosis). The median MELD 3.0 score at admission was 25 (20-33), with an estimated survival of 73.7% at 30 days. The MELD 3.0 score had a better performance in predicting 30-day mortality (AUC:0.761, 95%CI:0.732-0.791) compared with MELD sodium (MELD-Na; AUC: 0.744, 95% CI: 0.713-0.775; p = 0.042) and Maddrey's discriminant function (mDF) (AUC: 0.724, 95% CI: 0.691-0.757; p = 0.013). However, MELD 3.0 did not perform better than traditional MELD (AUC: 0.753, 95% CI: 0.723-0.783; p = 0.300) and Age-Bilirubin-International Normalised Ratio-Creatinine (ABIC) (AUC:0.757, 95% CI: 0.727-0.788; p = 0.765). These results were consistent in competing-risk analysis, where MELD 3.0 (AUC: 0.757, 95% CI: 0.724-0.790) predicted better 30-day mortality compared with MELD-Na (AUC: 0.739, 95% CI: 0.708-0.770; p = 0.028) and mDF (AUC:0.717, 95% CI: 0.687-0.748; p = 0.042). The MELD 3.0 score was significantly better in predicting renal replacement therapy requirements during admission compared with the other scores (AUC: 0.844, 95% CI: 0.805-0.883). MELD 3.0 demonstrated better performance compared with MELD-Na and mDF in predicting 30-day and 90-day mortality, and was the best predictor of renal replacement therapy requirements during admission for AH. However, further prospective studies are needed to validate its extensive use in AH. Severe AH has high short-term mortality. The establishment of treatments and liver transplantation depends on mortality prediction. We evaluated the performance of the new MELD 3.0 score to predict short-term mortality in AH in a large global cohort. MELD 3.0 performed better in predicting 30- and 90-day mortality compared with MELD-Na and mDF, but was similar to MELD and ABIC scores. MELD 3.0 was the best predictor of renal replacement therapy requirements. Thus, further prospective studies are needed to support the wide use of MELD 3.0 in AH

Planes nacionales en derechos humanos : debates y reflexiones sobre experiencias latinoamericanas

Los textos reunidos en este libro dan cuenta de las tensiones y desafíos a la hora de generar políticas públicas en derechos humanos que sean inclusivas, que respondan a parámetros de participación ciudadana eficaces y con incidencia. También muestran la tensión observada ‒una vez más‒ entre el corto y el largo plazo: las temporalidades de los gobiernos y de los Estados. Asimismo, en estos escritos tenemos en cuenta el análisis de contextos y políticas desde el enfoque de derechos humanos que nos permite detectar que, con mucha frecuencia, los Planes de esta naturaleza ‒en tanto herramienta provista por instancias internacionales de protección‒ no terminan de ser implementadas en el nivel nacional o subnacional, sino que muchas veces se construyen como modos de agradar a las agendas internacionales, más que como formas de convocar e interpelar a los pueblos en iniciativas colectivas de transformación. Por ello, intentamos construir propuestas interpretativas que permitan analizar críticamente ‒y también fortalecer‒ a los planes de derechos humanos en estos caminos ambiguos de formulación, puesta en práctica y evaluación, porque creemos que estas políticas integrales y transversales son, o pueden ser, instrumentos para construir sociedades más justas e incluyentes, pero requieren trabajo y compromiso de largo alcance. De la Presentació