The effect of sintering temperature on the properties of the BiOCl films for potential application in DSSC

In this work, BiOCl films were obtained by tape casting using BiOCl powders synthesized by the co-precipitation method. The effect of the film's sintering temperature (300 °C–600 °C) on the morphology, chemical composition, crystalline phases and optical characteristics was studied. The obtained BiOCl powders showed a flake-like morphology, a tetragonal crystalline structure without secondary phases and a wide band gap of 3.53 eV. For BiOCl films, results indicated that as the sintering temperature increased the flake-like shaped particles changed to rectangular ones while the amount of chlorine in the films decreased. A phase transition from tetragonal BiOCl to monoclinic Bi24O31Cl10 was also observed as the sintering temperature increased. Consequently, optical studies revealed that the band gap of BiOCl films decreased from 3.03 eV to 2.82 eV. FTIR analysis demonstrated that the organic groups were removed from the films only for sintering temperatures above 400 °C. The Rhodamine B dye adsorption capacity of BiOCl films decreased with increasing sintering temperature. The results obtained allow us to conclude that BiOCl films are suitable for use in DSSC when the sintering temperature is in the range of 400–500 °C

Synthesis of BiOI/Mordenite Composites for Photocatalytic Treatment of Organic Pollutants Present in Agro-Industrial Wastewater

Recently, bismuth oxyiodide (BiOI) is an attractive semiconductor to use in heterogeneous photocatalysis processes. Unfortunately, BiOI individually shows limited photocatalytic efficiency, instability, and a quick recombination of electron/holes. Considering the practical application of this semiconductor, some studies show that synthetic zeolites provide good support for this photocatalyst. This support material permits a better photocatalytic efficiency because it prevents the quick recombination of photogenerated pairs. However, the optimal conditions (time and temperature) to obtain composites (BiOI/ synthetic zeolite) with high photocatalytic efficiency using a coprecipitation-solvothermal growth method have not yet been reported. In this study, a response surface methodology (RSM) based on a central composite design (CCD) was applied to optimize the synthesis conditions of BiOI/mordenite composites. For this purpose, eleven BiOI/mordenite composites were synthesized using a combined coprecipitation-solvothermal method under different time and temperature conditions. The photocatalytic activities of the synthesized composites were evaluated after 20 min of photocatalytic oxidation of caffeic acid, a typical organic pollutant found in agro-industrial wastewater. Moreover, BiOI/mordenite composites with the highest and lowest photocatalytic activity were physically and chemically characterized using nitrogen adsorption isotherms, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and diffuse reflectance spectroscopy (DRS). The optimal synthesis conditions prove to be 187 °C and 9 h. In addition, the changes applied to the experimental conditions led to surface property modifications that influenced the photocatalytic degradation efficiency of the BiOI/mordenite composite toward caffeic acid photodegradation

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Effect of supporting electrolyte concentration on one-step electrodeposited CuInS2 films for ZnS/CuInS2 solar cell applications

A one-step electrodeposition process was used to obtain CuInS2 (CIS) films on a molybdenum substrate by varying the supporting electrolyte (lithium chloride, LiCl) concentration. The as-deposited samples were characterized by scanning electron microscopy, energy-dispersive spectroscopy, profilometry, and diffuse reflectance spectroscopy. From characterization, it was found that different concentrations of LiCl mainly lead to a morphological change in the obtained CIS films. Moreover, their chemical composition shifted to the stoichiometric composition for high concentrations of the supporting electrolyte. After annealing, the structural analysis from X-ray diffraction revealed that all samples crystallized in the tetragonal phase of CIS. In addition, it was found that the crystallite size increased for samples grown at higher concentrations of LiCl. Optical studies carried out by diffuse reflectance spectroscopy revealed that the band gap values increased from ~ 1.40 to ~ 1.45 eV (average) after the annealing process. Finally, zinc sulfide (ZnS) thin films were chemically deposited onto electrodeposited CIS films in order to evaluate the photovoltaic response of ZnS/CIS bilayer systems. We discovered that ZnS thin films covered the surface of CIS more effectively for the highest concentration of LiCl and that only the ZnS/CIS bilayer with the CIS film obtained at the highest concentration of LiCl showed a photovoltaic response.This work was financially supported by the Comisión Nacional de Ciencia y Tecnología (CONICYT) through the project FONDECYT Iniciación 11160368 and Gobierno de Aragón–Fondo Social Europeo (E14 17R).Peer reviewe

Solvothermal synthesis of BiOI microspheres: Effect of the reaction time on the morphology and photocatalytic activity

International audienceBiOI microspheres were synthesized by a solvothermal synthesis route from Bi(NO3)3*5H2O, using ethylene glycol in the presence of the ionic liquid 1-butyl-3-methylimidazolium iodide. The autoclave temperature was maintained constant at 120 °C and the reaction time was varied from 2 to 48 h. The obtained materials were characterized by XRD, SEM, TEM, EDS, nitrogen adsorption, FTIR and DRS. In addition, the photocatalytic activity of synthesized BiOI was evaluated in the oxidation of caffeic acid under simulated solar irradiation. Samples obtained between 12 and 24 h of synthesis present microsphere shapes and higher photocatalytic activity. All materials exhibit higher activities than TiO2 Evonik P25 used as standard catalyst

Fabrication of CdS/PbS and CdS:Al/PbS solar cells: Optimization of the Al content in CdS and the solution pH during PbS deposition

The CdS/PbS and CdS:Al/PbS thin film solar cells were fabricated using chemical bath deposition (CBD) process. The CdS thin film was deposited onto the ITO/glass substrate with different aluminum dopant concentration, whereas PbS layer was deposited over CdS thin film with different solution pH. The deposited CdS, CdS:Al and PbS thin films were characterized by scanning electron microscopy (SEM), Xray diffraction (XRD), diffuse reflectance spectroscopy (DRS), Rutherford Backscattered Spectroscopy (RBS) and Hall effect measurements. The results indicated that the aluminum concentration in CdS films reduces the crystallite size and increases the band gap and film resistivity. From PbS film characterization, it was obtained that increasing the solution pH the crystallite size augmented, meanwhile the band gap and electrical resistivity decreased. Photovoltaic characteristic performed to the different thin films solar cells, revealed that the highest conversion efficiency (ɳ %) 1.45% was observed in the bilayer system composed by a CdS layer doped with 9% of Al, and a PbS film grown at pH 10. Interestingly, CdS film with the highest resistivity and PbS with a medium band gap (1.48 eV) resulted in the highest conversion efficiency. Characterization of CdS, PbS and CdS/PbS samples suggested that the crystallite size, band gap and electrical resistivity were easily tuned with the help of CBD process that enhanced photo-conversion efficiency of the solar cells.Fil: Rodríguez, C.A.. Universidad de La Serena; ChileFil: Mera, Adriana C.. Universidad de La Serena; ChileFil: Pizarro Castillo, L.. Universidad de La Serena; ChileFil: Ashfaq, Mohammad. Universidad de La Serena; Chile. BS Abdur Rahman Crescent Institute of Science and Technology; IndiaFil: Sandoval Paz, M.G.. Universidad de Concepción; ChileFil: Cortés Burgos, María José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche | Comisión Nacional de Energía Atómica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología. Unidad Ejecutora Instituto de Nanociencia y Nanotecnología - Nodo Bariloche; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro | Universidad Nacional de Cuyo. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro; ArgentinaFil: Manidurai, Paulraj. Universidad de Concepción; ChileFil: Suárez, S.. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro | Universidad Nacional de Cuyo. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro; Argentin

Intraregional Migration in Latin America: Psychological perspectives on acculturation and intergroup relations.

This book addresses the psychosocial causes, consequences, and underpinnings of intraregional migration in Latin America. War, political instability, and disparities in wealth and opportunity have long driven migration within Latin America, and this process shows no sign of slowing. In this book, cross-cultural and social psychologists address the urgent issues that face migrants throughout Central and South America. This includes overt prejudice and discrimination, particularly toward immigrants of indigenous or African-American origin; microaggressions; the tendency to positively value fair skin and European surnames; as well as political questions regarding the nature of citizenship and nationhood and links between legacies of colonialism and slavery and present-day inequality. Contributors offer conceptual, theoretical, and methodological tools for understanding the psychological processes that underlie migration and intergroup contact. Chapters focus on migration between and within countries in Central and South America, including Chile, Argentina, Bolivia, Costa Rica, Mexico, Peru, and Brazil.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Instituto de Investigaciones Psicológicas (IIP

Novel genes and sex differences in COVID-19 severity.

Here we describe the results of a genome-wide study conducted in 11 939 COVID-19 positive cases with an extensive clinical information that were recruited from 34 hospitals across Spain (SCOURGE consortium). In sex-disaggregated genome-wide association studies for COVID-19 hospitalization, genome-wide significance (p < 5x10-8) was crossed for variants in 3p21.31 and 21q22.11 loci only among males (p = 1.3x10-22 and p = 8.1x10-12, respectively), and for variants in 9q21.32 near TLE1 only among females (p = 4.4x10-8). In a second phase, results were combined with an independent Spanish cohort (1598 COVID-19 cases and 1068 population controls), revealing in the overall analysis two novel risk loci in 9p13.3 and 19q13.12, with fine-mapping prioritized variants functionally associated with AQP3 (p = 2.7x10-8) and ARHGAP33 (p = 1.3x10-8), respectively. The meta-analysis of both phases with four European studies stratified by sex from the Host Genetics Initiative confirmed the association of the 3p21.31 and 21q22.11 loci predominantly in males and replicated a recently reported variant in 11p13 (ELF5, p = 4.1x10-8). Six of the COVID-19 HGI discovered loci were replicated and an HGI-based genetic risk score predicted the severity strata in SCOURGE. We also found more SNP-heritability and larger heritability differences by age (<60 or ≥ 60 years) among males than among females. Parallel genome-wide screening of inbreeding depression in SCOURGE also showed an effect of homozygosity in COVID-19 hospitalization and severity and this effect was stronger among older males. In summary, new candidate genes for COVID-19 severity and evidence supporting genetic disparities among sexes are provided