In-situ growth of nonstoichiometric CrO0.87 and Co3O4 hybrid system for the enhanced electrocatalytic water splitting in alkaline media

The development of electrocatalysts for electrochemical water splitting has received considerable attention in response to the growing demand for renewable energy sources and environmental concerns. In this study, a simple hydrothermal growth approach was developed for the in-situ growth of non-stoichiometric CrO0.87 and Co3O4 hybrid materials. It is apparent that the morphology of the prepared material shows a heterogeneous aggregate of irregularly shaped nanoparticles. Both CrO0.87 and Co3O4 have cubic crystal structures. Its chemical composition was governed by the presence of Co, Cr, and O as its main constituents. For understanding the role CrO0.87 plays in the half-cell oxygen evolution reaction (OER) in alkaline conditions, CrO0.87 was optimized into Co3O4 nanostructures. The hybrid material with the highest concentration of CrO0.87 was found to be highly efficient at driving OER reactions at 255 mV and 20 mA cm−2. The optimized material demonstrated excellent durability for 45 h and a Tafel slope of 56 mV dec−1. Several factors may explain the outstanding performance of CrO0.87 and Co3O4 hybrid materials, including multiple metallic oxidation states, tailored surface properties, fast charge transport, and surface defects. An alternative method is proposed for the preparation of new generations of electrocatalysts for the conversion and storage of energy

Regulating C₂H₂/CO₂ adsorption selectivity by electronic-state manipulation of iron in metal-organic frameworks

The separation of C2H2 from C2H2/CO2 mixture is of great importance, yet highly challenging in the petrochemical industry due to their similar physicochemical properties. While open-metal sites (OMSs) in metal-organic frameworks (MOFs) are known to possess high affinity toward C2H2, its selective adsorption performance regulated by the electronic state of the same OMSs remains unexplored. Here, we report a metal electronic-state manipulation approach to construct a pair of isostructural Fe-MOFs, namely LIFM-26(Fe[II]/Fe[III]) and LIFM-27(Fe[III]) with different Fe[II] or Fe[III] oxidation states on the Fe centers, which display mixed-valent Fe[II]/Fe[III] centers in the former and sole Fe[III] centers in the latter. Remarkably, LIFM-26(Fe[II]/Fe[III]) shows significantly enhanced C2H2 uptake capacity than LIFM-27(Fe[III]), attested by adsorption isotherms and IAST calculations, as well as simulated and experimental breakthrough experiments. Furthermore, in situ infrared (IR) and molecular calculations unveil that the presence of Fe[II] in LIFM-26(Fe[II]/Fe[III]) results in stronger Fe[II]–C2H2 interactions than Fe[III]–C2H2, which plays a key role in the C2H2/CO2 separation

Low-cost and biodegradable thermoelectric devices based on van der Waals semiconductors on paper substrates

We present a method to fabricate handcrafted thermoelectric devices on standard office paper substrates. The devices are based on thin films of WS2, Te, and BP (P-type semiconductors) and TiS3 and TiS2 (N-type semiconductors), deposited by simply rubbing powder of these materials against paper. The thermoelectric properties of these semiconducting films revealed maximum Seebeck coefficients of (+1.32 ± 0.27) mV/K and (-0.82 ± 0.15) mV/K for WS2 and TiS3, respectively. Additionally, Peltier elements were fabricated by interconnecting the P-type and N-type films with graphite electrodes. A thermopower value up to 6.11 mV/K was obtained when the Peltier element is constructed with three junctions. The findings of this work show proof-of-concept devices to illustrate the potential application of semiconducting van der Waals materials in future thermoelectric power generation as well as temperature sensing for low-cost disposable electronic device

Enhancement of Exchange Bias and Perpendicular Magnetic Anisotropy in CoO/Co Multilayer Thin Films by Tuning the Alumina Template Nanohole Size

The interest in magnetic nanostructures exhibiting perpendicular magnetic anisotropy and exchange bias (EB) effect has increased in recent years owing to their applications in a new generation of spintronic devices that combine several functionalities. We present a nanofabrication process used to induce a significant out-of-plane component of the magnetic easy axis and EB. In this study, 30 nm thick CoO/Co multilayers were deposited on nanostructured alumina templates with a broad range of pore diameters, 34 nm ≤ Dp ≤ 96 nm, maintaining the hexagonal lattice parameter at 107 nm. Increase of the exchange bias field (HEB) and the coercivity (HC) (12 times and 27 times, respectively) was observed in the nanostructured films compared to the non-patterned film. The marked dependence of HEB and HC with antidot hole diameters pinpoints an in-plane to out-of-plane changeover of the magnetic anisotropy at a nanohole diameter of ∼75 nm. Micromagnetic simulation shows the existence of antiferromagnetic layers that generate an exceptional magnetic configuration around the holes, named as antivortex-state. This configuration induces extra high-energy superdomain walls for edge-to-edge distance >27 nm and high-energy stripe magnetic domains below 27 nm, which could play an important role in the change of the magnetic easy axis towards the perpendicular directionEl interés por las nanoestructuras magnéticas que exhiben anisotropía magnética perpendicular y efecto de sesgo de intercambio (EB) ha aumentado en los últimos años debido a sus aplicaciones en una nueva generación de dispositivos espintrónicos que combinan varias funcionalidades. Presentamos un proceso de nanofabricación utilizado para inducir una componente significativa fuera del plano del eje magnético fácil y del EB. En este estudio, se depositaron multicapas de CoO/Co de 30 nm de espesor sobre plantillas de alúmina nanoestructurada con un amplio rango de diámetros de poro, 34 nm ≤ Dp ≤ 96 nm, manteniendo el parámetro de red hexagonal en 107 nm. Se observó un aumento del campo de polarización de intercambio (HEB) y de la coercitividad (HC) (12 veces y 27 veces, respectivamente) en las películas nanoestructuradas en comparación con la película sin patrón. La marcada dependencia de HEB y HC con los diámetros de los agujeros antidotados señala un cambio de la anisotropía magnética de dentro a fuera del plano a un diámetro de nanoagujero de ∼75 nm. La simulación micromagnética muestra la existencia de capas antiferromagnéticas que generan una configuración magnética excepcional alrededor de los agujeros, denominada estado de antivórtice. Esta configuración induce paredes de superdominio extra de alta energía para la distancia de borde a borde >27 nm y dominios magnéticos de franja de alta energía por debajo de 27 nm, que podrían desempeñar un papel importante en el cambio del eje magnético fácil hacia la dirección perpendicula

Outcomes Among Patients with Breakthrough SARS-CoV-2 Infection After Vaccination.

BACKGROUND: Breakthrough infections after SARS-CoV-2 vaccination have been reported. Clinical outcomes in these persons are not widely known. METHODS: We evaluated all vaccinated persons with breakthrough infection ≥14 days after the second vaccine dose and unvaccinated controls matched on age, sex, nationality, and reason for testing between December 23, 2020 and March 28, 2021 in Qatar. Our primary outcome was severe disease defined as hospitalization, mechanical ventilation, or death. RESULTS: Among 456 persons cases of breakthrough infection and 456 unvaccinated matched controls with confirmed infection, median age was 45 years, 60.7% were males, and ≥1 comorbid condition was present in 61.2% of the vaccinated and 47.8% of the unvaccinated persons (P=0.009). Severe disease was recorded in 48 (10.5%) of the vaccinated and 121 (26.5%) of the unvaccinated group (P40-60 years, HR 2.32; >60-70 years, HR 4.34; >70 years, HR 5.43); presence of symptoms at baseline (HR 2.42, 95%CI 1.44-4.07); and being unvaccinated (HR 2.84, 95%CI 1.80-4.47). CONCLUSIONS: In persons with breakthrough SARS-CoV-2 infection, increasing age is associated with a higher risk of severe disease or death, while vaccination is associated with a lower risk. Presence of comorbidities was not associated with severe disease or death among persons with breakthrough infection

Tetrabenzoporphyrin and -mono-, - Cis -di- and tetrabenzotriazaporphyrin derivatives: Electrochemical and spectroscopic implications of meso CH Group replacement with nitrogen

Nonperipherally hexyl-substituted metal-free tetrabenzoporphyrin (2H-TBP, 1a) tetrabenzomonoazaporphyrin (2H-TBMAP, 2a), tetrabenzo-cis-diazaporphyrin (2H-TBDAP, 3a), tetrabenzotriazaporphyrin (2H-TBTAP, 4a), and phthalocyanine (2H-Pc, 5a), as well as their copper complexes (1b-5b), were synthesized. As the number of meso nitrogen atoms increases from zero to four, Îmax of the Q-band absorption peak becomes red-shifted by almost 100 nm, and extinction coefficients increased at least threefold. Simultaneously the blue-shifted Soret (UV) band substantially decreased in intensity. These changes were related to the relative electron-density of each macrocycle expressed as the group electronegativity sum of all meso N and CH atom groups, âχR. X-ray photoelectron spectroscopy differentiated between the three different types of macrocyclic nitrogen atoms (the Ninner, (NH)inner, and Nmeso) in the metal-free complexes. Binding energies of the Nmeso and Ninner,Cu atoms in copper chelates could not be resolved. Copper insertion lowered especially the cathodic redox potentials, while all four observed redox processes occurred at larger potentials as the number of meso nitrogens increased. Computational chemical methods using density functional theory confirmed 1b to exhibit a Cu(II) reduction prior to ring-based reductions, while for 2b, Cu(II) reduction is the first reductive step only if the nonperipheral substituents are hydrogen. When they are methyl groups, it is the second reduction process; when they are ethyl, propyl, or hexyl, it becomes the third reductive process. Spectro-electrochemical measurements showed redox processes were associated with a substantial change in intensity of at least two main absorbances (the Q and Soret bands) in the UV spectra of these compounds

Regulating C2H2/CO2 adsorption selectivity by electronic-state manipulation of iron in metal-organic frameworks

Article reports a metal electronic-state manipulation strategy to construct a pair of isostructural and interconvertible Fe-MOFs featuring open Fe centers with different electron densities for efficient C₂H₂/CO₂ separation. The authors show that the presence of Fe[II] centers with a medium-spin-state trail plays a crucial role in the enhanced C₂H₂ selective adsorption

Anales de Edafología y Agrobiología Tomo 34 Número 3-4

Estudio de la materia orgánica del ranker atlántico. I. Caracterización general, por P. Rodríguez Seoane, T. Carballas y F. Guitián Ojea.-- Movimiento y distribución de sales solubles en suelos calizos, por F. G. Fernández, M. Caro y A. Cerda.-- The availability of added and native phosphorus to barley grown in sorne Egyptian soils .containing different levels of calciurn carbonate, by M. H. Nafady.-- The measurernent of soil pH in calciurn chloride solutions, by M. H. Nafady.- Nuevas aportaciones al conocimiento del género Mnema (nernatoda) y su distribución en los suelos españoles, por María Arias.-- Estudios bioquímicos y fisiológicos en aceituna. III. Variaciones en el crecimiento de hojas y frutos, por J. P. Donaire, A. J. Sánchez-Raya, J. López Corge y L. Recalde.-- Importancia de la rnicorrización espontánea en ensayos de nutrición vegetal en suelos deficientes en fósforo, por R. Azcón y J. M. Barea.-- Andosoles canarios. J. Características generales de estos suelos, por E. Fernández Caldas y M. L. Tejedor Salguero.-- Andosoles canarios. II. Intergrados andosol-tierra parda oligotrófica. Características morfológicas y quírnkas, por M. L. Tejedor Salguero y E. Fernández Caldas.-- Andosoles canarios. lll. Jntergrados andosol-tierra parda otigotrófica. Catacterísticas físicas, por E. Fernández Caldas y M. L. Tejedor Salguero.-- Andosoles canario;. IV. In ter grados andosol-tierra parda ohgotrófica. Características mineralógicas. Interpretación y clasificación, por C. Rodríguez Pascual, P. Quantin, M. L. Tejedor Salguero y E. Fernández Caldas.-- Estudios recapitualtivos.-- La vid una revisión de las condiciones del cultivo, por C. González O. y M. Lachica.—Notas científicas.-- Nota sobre la determinación del carbono orgánico en suelos, por J. F. Gallardo.—Notas.-- Ampliación de la Comisión Permanente de la Junta de Gobierno del Patronato Alonso de Herrera.-- Nombramiento de Secretario del Centro de Edafología y Biología Aplicada de Tenerife.-- Nombramientos en el Instituto de Alimentación v Productividad Animal.-- Cambio de representantes del Patronato Alonso de Herrera en la Comisión Asesora de la Investigación Científica y Técnica.-- Convenio con ASPA.-- Dimisión del Director del Centro de Edafología y Biología Aplicada del Segura de Murcia.-- Nombramientos de representantes en los C. R. l. D. A. S.-- Designación de Jurados para Premios del C. S. l. C.-- Informes del Secretario Adjunto del C. S. I. C. sobre reuniones en Europa.-- Convenio entre la Estación Experimental del Zaidín y la Universidad de Nápoles.-- Donación de terrenos a la Diputación de Badajoz.-- Seminario Oleícola Internacional.-- Congreso de la Unión Fitopatológica Mediterránea.-- Situaciones de personal.-- Reunión de la Comisión de Protección Vegetal.-- Día Forestal Mundial.-- Congresos y reuniones internacionales y viajes.-- Premio Agrícola Aedos.-- BibliografíaPeer reviewed2019-08.- CopyBook.- Libnova.- Biblioteca ICA

Herd immunity against severe acute respiratory syndrome coronavirus 2 infection in 10 communities, qatar

We investigated what proportion of the population acquired severe acute respiratory syndrome coronavirus 2 (SARSCoV- 2) infection and whether the herd immunity threshold has been reached in 10 communities in Qatar. The study included 4,970 participants during June 21-September 9, 2020. Antibodies against SARS-CoV-2 were detected by using an electrochemiluminescence immunoassay. Seropositivity ranged from 54.9% (95% CI 50.2%-59.4%) to 83.8% (95% CI 79.1%-87.7%) across communities and showed a pooled mean of 66.1% (95% CI 61.5%-70.6%). A range of other epidemiologic measures indicated that active infection is rare, with limited if any sustainable infection transmission for clusters to occur. Only 5 infections were ever severe and 1 was critical in these young communities; infection severity rate of 0.2% (95% CI 0.1%-0.4%). Specifi c communities in Qatar have or nearly reached herd immunity for SARS-CoV-2 infection: 65%-70% of the population has been infected.This study was supported by the Hamad Medical Corporation, Ministry of Public Health, and the Biomedical Research Program and the Biostatistics, Epidemiology, and Biomathematics Research Core, both atScopu

Anales de Edafología y Agrobiología Tomo 33 Número 9-10

Estudio del equilibrio nutritivo en cultivos de chirimoyo (Annona cherimolia), por César González O., Miguel Fuentes y Soledad Díaz.-- Resistencia a la desecación del tejido foliar y cierre de estomas en alfalfa (M edicago sativa L.) y trébol blanco (Trijolium repens L.) con relación al déficit agua, por M. Sánchez-Díaz y M. Sánchez-Marín.-- Determinación del calor isostérico y consideraciones sobre el mecanismo de la adsorción de fosfato por óxidos de hierro, por L. Madrid, F. Cabrera, P. de Arambarri y E. Díaz.-- Studies on sodium-calcium exchange equilibria. II. In Egyptian soils, by M. H. Nafady.-- Indices nutritivos en manzano (var. R. Delicious), por C. González, O. M. Rodríguez M., J. Solé D. y A. Wylie W.-- Caracteres de los suelos de las zonas citrícolas del valle de Murcia (España), por J. A. Sánchez F., F. Artes y J. López-Tarruella.-- Estudio micromorfológico de suelos desarrollados sobre andesitas en Andalucía oriental, por J. Aguilar y M. Delgado.-- Estudio edafológico de los relieves próximos a la vega de Motril, por J. Aguilar, Ruiz, A. Monge Ureña y C. Sierra Ruiz de la F.-- Consideraciones experimentales sobre el análisis de boro en plantas, por A. León, F.J. López-Andréu, F. Romojaro y C. Alcaraz.-- Efectos de la aplicación conjunta de fertilizantes químicos y microbianos (Azotobaeter Fosjobaeterias) en cultivos enarenados de tomate, por R. Azcón, M. Gómez y J. M. Barea.-- Formas de calcio en suelos del piso tropical de Barbacoas, Colombia, por G. Hugo Eraso, L. Federman Ortiz y O. Hernán Burbano.-- Compuestos íenólicos en Eriea vagans L., por J. Arinés, J. L. G. Mantilla y E. Vieitiz.-- Determinación de glúcidos en plantas por fotocolorimetría. Estudio comparativo de métodos clásicos y automáticos, por C. Cadahía y M. T. Piñeiro.-- Notas. Nombramiento de Consejeros Adjuntos del Patronato Alonso de Herrera.-- Nombramiento y cese de Vocales de la Junta de Gobierno del Patronato Alonso de Herrera.--Fallo de los Premios Alonso de Herrera y Antonio José de Cavanilles.-- Propuesta del Instituto de Alimentación y Productividad Animal sobre nombramiento de Vicedirector del mismo.-- Congresos y Reuniones internacionales.-- Creación de la Comisión Conjunta de Investigación Agraria de los Ministerios de Educación y Ciencia y de Agricultura.-- Restauración y adecuación del Jardín Botánico de Madrid.-- III Reunión Nacional de Centros de Investigación Ganadera Tribunales.-- Clausura del XI Curso Internacional de Edafología y Biología Vegetal.-- 7th International Colloquium on Plant Analysis and Fertilizer Problems.-- X Congreso Internacional de Ciencia del Suelo.-- Clausura del IV Congreso de Ciencia y Tecnología de Alimentos.-- 50th Anniversary Meeting of the British Society for Experimental Biología.-- XXIX Symposium on Symbiosis, Society for Experimental Biología.-- IV Reunión de la Sociedad Español de Microscopía Electrónica.-- Subvención de la Fundación Barrie de la Maza a la Misión Biológica de Galicia.-- Conferencia.-- Los universitarios y la defensa de la naturaleza.-- Seminario, sobre Tipos diferentes de costras calizas y su distribución regional.-- BibliografíaPeer reviewed2019-08.- CopyBook.- Libnova.- Biblioteca ICA