Femtosecond-laser-irradiation-induced structural organization and crystallinity of Bi2WO6

Controlling the structural organization and crystallinity of functional oxides is key to enhancing their performance in technological applications. In this work, we report a strong enhancement of the structural organization and crystallinity of Bi2WO6 samples synthetized by a microwave-assisted hydrothermal method after exposing them to femtosecond laser irradiation. X-ray difraction, UVvis and Raman spectroscopies, photoluminescence emissions, energy dispersive spectroscopy, feld emission scanning electron microscopy, and transmission electron microscopy were employed to characterize the as-synthetized samples. To complement and rationalize the experimental results, frstprinciples calculations were employed to study the efects of femtosecond laser irradiation. Structural and electronic efects induced by femtosecond laser irradiation enhance the long-range crystallinity while decreasing the free carrier density, as it takes place in the amorphous and liquid states. These efects can be considered a clear cut case of surface-enhanced Raman scattering

Effects of surface stability on the morphological transformation of metals and metal oxides as investigated by first-principles calculations

Morphology is a key property of materials. Owing to their precise structure and morphology, crystals and nanocrystals provide excellent model systems for joint experimental and theoretical investigations into surface-related properties. Faceted polyhedral crystals and nanocrystals expose well-defined crystallographic planes depending on the synthesis method, which allow for thoughtful investigations into structure-reactivity relationships under practical conditions. This feature article introduces recent work, based on the combined use of experimental findings and first-principles calculations, to provide deeper knowledge of the electronic, structural, and energetic properties controlling the morphology and the transformation mechanisms of different metals and metal oxides: Ag, anatase TiO2, BaZrO3, and α-Ag2WO4. According to the Wulff theorem, the equilibrium shapes of these systems are obtained from the values of their respective surface energies. These investigations are useful to gain further understanding of how to achieve morphological control of complex three-dimensional crystals by tuning the ratio of the surface energy values of the different facets. This strategy allows the prediction of possible morphologies for a crystal and/or nanocrystal by controlling the relative values of surface energies.The authors are grateful to FAPESP (2013/07296-2, 2012/ 14468-1, 2013/26671-9 and 2014/04350-9), CAPES (process A104/2013 and 99999.002998/2014-09), CNPq INCTMN 573636/2008-7, PrometeoII/2014/022 and ACOMP/2014/270 projects (Generalitat Valenciana), Ministerio de Economia y Competitividad (Spain), CTQ2012- 36253-C03-02 and the Spanish Brazilian program (PHB2009-0065-PC) for financially supporting this research. We also acknowledge the Servei Informática, Universitat Jaume I for a generous allotment of computer time

A 3D platform for the morphology modulation of materials: first principles calculations on the thermodynamic stability and surface structure of metal oxides: Co3O4, α-Fe2O3, and In2O3

Essentially, the exposed crystal planes of a given material, which primarily determine their morphology, tremendously affect its behavior. First principle calculations, based on the Wulff construction model and broken bonding density index, have been performed to calculate the equilibrium and their transformations for different metal oxides: Co3O4, α-Fe2O3, and In2O3. Present results point out that starting by surface thermodynamics is a helpful approach to predict and assess the morphology transformations of these materials. These complete set of morphologies may serve as a guide for researchers, when analyzing the images from electron microscopies, to gain further understanding of how to control crystal shape synthetically by tuning the surface chemistry and by controlling the relative values of surface energies

Back to the basics: probing the role of surfaces in the experimentally observed morphological evolution of ZnO

Although the physics and chemistry of materials are driven by exposed surfaces in the morphology, they are fleeting, making them inherently challenging to study experimentally. The rational design of their morphology and delivery in a synthesis process remains complex because of the numerous kinetic parameters that involve the effective shocks of atoms or clusters, which end up leading to the formation of different morphologies. Herein, we combined functional density theory calculations of the surface energies of ZnO and the Wulff construction to develop a simple computational model capable of predicting its available morphologies in an attempt to guide the search for images obtained by field-emission scanning electron microscopy (FE-SEM). The figures in this morphology map agree with the experimental FE-SEM images. The mechanism of this computational model is as follows: when the model is used, a reaction pathway is designed to find a given morphology and the ideal step height in the whole morphology map in the practical experiment. This concept article provides a practical tool to understand, at the atomic level, the routes for the morphological evolution observed in experiments as well as their correlation with changes in the properties of materials based solely on theoretical calculations. The findings presented herein not only explain the occurrence of changes during the synthesis (with targeted reaction characteristics that underpin an essential structure–function relationship) but also offer deep insights into how to enhance the efficiency of other metal-oxide-based materials via matching

The hinge morphology of SnO2 as multifunctional semiconductor: What we can learn from simulations, theory, and experiments

Our interaction with materials occurs through their surfaces whose properties are strongly dependent on morphology, structure, and atomic arrangement. Unfortunately, obtaining a detailed correlation between the surface morphology with its properties is not straightforward. SnO2 is a multifunctional semiconductor ceramic that is exploited in several technological devices from sensor to energy storage, water splitting, and solar to fuel photocatalysis. This work focused on the structural, energetic, and electronic properties of low and high index surfaces of SnO2 semiconductor and assessed the morphology-dependent process via first-principles calculations, at the density functional theory level. Importantly, our explicitly dynamic approach elucidates the atomic arrangements and stability of the exposed surfaces to provide a close match between experimental field emission scanning electron microscopy images and computational simulation. These findings can potentially set a foundation for establishing synthesis techniques for drive the morphology evolution through the control of temperature/pressure, and/or based on surface interactions of the selective adsorption of solvents/surfactants.This work was supported by Generalitat Valenciana, Universitat Jaume I, and São Paulo Research Foundation (FAPESP, grant number 2013/07296-2 and 2022/08048-1). A.F.G. acknowledges the Generalitat Valenciana (Conselleria de Innovación, Universidades, Ciencia y Sociedad Digital) for the postdoctoral contract (CIAPOS/2021/106) and Universitat Jaume I for the funding though its Research Stay Grants (E-2022-05). J.A. acknowledges Universitat Jaume I (project UJI-B2019-30), and Generalitat Valenciana (Conselleria de Innovación, Universidades, Ciencia y Sociedad Digital – project CIAICO/2021/122) for financially supporting this research

In situ Formation of Metal Nanoparticles through Electron Beam Irradiation: Modeling Real Materials from First-Principles Calculations

Advances in electron-matter studies, based on the irradiation of the electron beam in the transmission electron microscopy or field emission-scanning electron microscope on materials represents a preferred external physical and chemical tool for in situ remote command of the functional attributes of nanomaterials associated to its unique advantages of high spatial and temporal resolution and digital controllability. This makes the field of electron beam irradiation an emerging topic open for many researchers right now. Electron-material interactions envisage the formation, growth and coalescence of metal nanoparticles induced by electron beam irradiations and motivated by this discovery, in this Review, we provide an account of the recent advancements and theoretical developments to describe this phenomena and their applications. A theoretical framework is developed to determine the physical principles involved in the mechanism for the formation of metal nanoparticles on different materials by electron beam irradiation under the guidance of first-principles calculations at density functional level. New research directions are emerging in materials science to reach many applications by providing a deeper insight in the properties and phenomena in complex material systems. We conclude our work by briefly outlining the challenges that need to be addressed and the opportunities that can be tapped into. We hope that the review of the flourishing and vibrant topic with myriad possibilities would shine light on exploring the future directions of this research field by encouraging and opening the windows to meaningful multidisciplinary cooperation of researchers from different backgrounds and scientists from the fields such as chemistry, physics, engineering, biology, nanotechnology and materials science

Mortalidade por doença renal crônica secundária à hipertensão no Brasil: um estudo do “Global Burden of Disease”

Background and Objectives: Chronic kidney disease (CKD) is one of the main complications resulting from arterial hypertension, and a recent increase in the incidence and prevalence of the disease has been reported, which can lead to an increase in mortality and complications resulting from the disease. Thus, the objective of study is to describe the variations in mortality from CKD secondary to arterial hypertension, in Brazil, between the years 1990 to 2019. Methods: Epidemiological study, with a quantitative approach and descriptive character, which analyzed data from the “Global Burden of Disease Study” (GBD) tool. Results: In all of Brazil’s federative units, the estimate of deaths from CKD secondary to hypertension increased, with the Southeast region having the highest estimates. The States of Rio de Janeiro, Rio Grande do Sul, and Paraíba lead with the highest mortality rates. Regarding sex, in all years, higher rates were observed in males, however, over the years, this difference has been reduced. The age group of ≥70 years was the most affected, standing out with the highest death rates. Conclusion: the burden of CKD in Brazil has increased in the last 30 years; among the regions of the country, the Southeast recorded the highest estimates of deaths in all the years analyzed, being mainly higher among men.Justificación y objetivos: La enfermedad renal crónica (ERC) es una de las principales complicaciones derivadas de la hipertensión arterial, y en los últimos años se ha reportado un aumento en la incidencia y prevalencia de la enfermedad, lo que puede conducir a un aumento de la mortalidad y de las complicaciones derivadas de esta, por lo tanto, el objetivo del estudio es describir las variaciones en la mortalidad por ERC secundaria a la hipertensión arterial en Brasil entre los años 1990 a 2019. Métodos: Estudio epidemiológico, con enfoque cuantitativo y carácter descriptivo, que analizó datos de la herramienta Global Burden of Disease Study (GBD). Resultados: En todas las unidades de la federación, aumentó la estimación de muertes por ERC secundaria a la hipertensión arterial, con la región Sudeste presentando las estimaciones más altas. Los estados de Rio de Janeiro, Rio Grande do Sul y Paraíba lideran con las tasas de mortalidad más altas. Con respecto al sexo, en todos los años se observaron mayores tasas en los varones, sin embargo, con el paso de los años, esta diferencia se ha ido reduciendo. El grupo de edad de ≥70 años fue el más afectado, destacándose con las tasas de mortalidad más altas. Conclusión: la carga de ERC en Brasil ha aumentado en los últimos 30 años; de las regiones del país, el Sudeste registró las mayores estimaciones de muertes en todos los años registrados entre los analizados, siendo principalmente mayor entre los hombres.Justificativa e objetivos: A doença renal crônica (DRC) é uma das principais complicações decorrentes da hipertensão arterial. Nos últimos anos, tem sido relatado um aumento na incidência e prevalência da doença, o que pode levar ao aumento da mortalidade e das complicações decorrentes da doença. Assim, o objetivo deste estudo foi descrever as variações da mortalidade por DRC secundária à hipertensão arterial no Brasil entre 1990 e 2019. Métodos: Trata-se de um estudo epidemiológico, de abordagem quantitativa e caráter descritivo, que analisou dados da ferramenta Global Burden of Disease Study (GBD). Resultados: Em todas as unidades da federação, a estimativa de mortes por DRC secundária à hipertensão apresentou aumento, a região Sudeste apresentando as maiores estimativas. Os estados do Rio de Janeiro, Rio Grande do Sul e Paraíba lideram as pesquisas com as maiores taxas de mortalidade. No que diz respeito ao sexo, em todos os anos foram observadas maiores taxas de DRC em indivíduos do sexo masculino; contudo, nota-se que tem ocorrido uma redução dessa diferença. A faixa etária de ≥70 anos foi a mais acometida, destacando-se com as maiores taxas de mortes. Conclusão: a carga de DRC no Brasil aumentou nos últimos 30 anos. Entre as regiões do país, o Sudeste registrou as maiores estimativas de mortes em todos os anos analisados, principalmente de homens

Surfactant-Mediated Morphology and Photocatalytic Activity of α‑Ag2WO4 Material

In the present work, the morphology (hexagonal rod-like vs cuboid-like) of an α-Ag2WO4 solid-state material is manipulated by a simple controlled-precipitation method, with and without the presence of the anionic surfactant sodium dodecyl sulfate (SDS), respectively, over short reaction times. Characterization techniques, such as X-ray diffraction analysis, Rietveld refinement analysis, Fourier-transform (FT) infrared spectroscopy, FT Raman spectroscopy, UV–vis spectroscopy, transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, energy-dispersive X-ray spectroscopy, field emission-scanning electron microscopy (FE-SEM), and photoluminescence emission, are employed to disclose the structural and electronic properties of the α-Ag2WO4 material. First-principles calculations were performed to (i) obtain the relative stability of the six low-index surfaces of α-Ag2WO4; (ii) rationalize the crystal morphologies observed in FE-SEM images (using the Wulff construction); and (iii) determine the energy profiles associated with the transformation process between both morphologies induced by the presence of SDS. Finally, we demonstrate a relationship between morphology and photocatalytic activity, evaluated by photodegradation of Rhodamine B dye under UV light, based on the different numbers of unsaturated superficial Ag and W cations (local coordination, i.e., clusters) of each surface

Laboratório de mudança: método para compreensão da crise entre universidade pública e sociedade

The purpose of this article is to analyze if a method of developmental intervention helps the professionals of the activities in interinstitutional crises to form a historical understanding of the problems faced and to create solutions for them. We present a method called Change Laboratory (CL), inspired by the Theory of Historical-Cultural Activity (THCA). It is illustrated with an empirical case of intervention where the historical genesis and the contradictions that led to the crisis in the collaborative relationship between a public university and an educational health center were identified, between 2013 and 2015. Data obtained from records made during the intervention as well as interviews and comments from the participants were used for the study. As a result, the participants analyzed their activities historically and designed the future collaboration activity aimed at a solution to the crisis, within the scope of possible academicpedagogical relations linked to the Brazilian National Health System (SUS). The analysis suggests contradictions in the objects of health care and education activities that may be at the heart of the problematic relationship among institutions that need to develop activities collaboratively. The CL as a methodology of developmental intervention integrates diagnosis, learning, the participants’ protagonism and the creation of solutions as part of the same process.O objetivo deste artigo é analisar se um método de intervenção formativa contribui para que os profissionais de atividades colaborativas formem uma compreensão histórica dos problemas enfrentados em crises interinstitucionais e criem soluções para essas situações. Apresentamos o método Laboratório de Mudança (LM), inspirado na Teoria da Atividade Histórico-Cultural (TAHC). Ele é ilustrado com um caso empírico de intervenção na qual foi identificada a gênese histórica e as contradições que levaram à crise entre uma universidade pública e um centro de saúde escola. Para o estudo foram utilizados dados obtidos a partir de registros efetuados ao longo da intervenção, entre 2013 e 2015, assim como entrevistas e comentários dos participantes. Como resultado, eles analisaram historicamente suas atividades e desenharam novos cenários de colaboração futura, visando uma solução para a crise, no âmbito de possíveis relações acadêmico-pedagógicas vinculadas ao Sistema Único de Saúde (SUS). A análise sugere a existência de contradições nos objetos das atividades de assistência à saúde e educação que podem estar no cerne da relação problemática entre outras instituições semelhantes que precisam desenvolver atividades colaborativamente. O LM, enquanto metodologia de intervenção formativa, integra diagnóstico, aprendizagem, protagonismo dos participantes e criação de soluções como parte de um mesmo processo