Fluorescence spectroscopy is an extremely sensitive analytical technique that has been widely used to elucidate problems that require low detection limits. Although fluorescence spectroscopy is widespread in industry and academia, there is a lack of teaching materials demonstrating its basic principles, as well as the influence of instrumental parameters involved in the technique, which limit its correct use and the full potential of it. For this reason, this work aims to explore the principles of fluorescence spectroscopy and correlate them in function of different instrumental variables to carry out a fluorescence experiment. The spectrofluorometer parameters such as the excitation wavelength, excitation and emission slits, step, integration time, detection geometry as well as concentration of the samples were varied to illustrate how the best resulting spectra can be registered free of artifacts. To do so, two organic dyes with structured vibronic bands (pyrene) and another with unstructured bands (rhodamine 6G) were used. Another study carried out involved the use of 3D spectra, excitation/emission spectra, of cadmium telluride (CdTe) quantum dots. In this case, it was possible to show the excitation spectrum of nanomaterials, collecting emissions at different wavelengths, as well as analyzing the particle size distribution. limits academia reason experiment wavelength slits step time artifacts so pyrene (pyrene rhodamine 6G G D excitationemission CdTe (CdTe dots case nanomaterials wavelengths distribution

Lead-free halide double perovskites with the formula A2BIBIIIX6, and ordered vacancy perovskites, with the general formula A2BIVX6 have recently emerged as alternative materials for advancements in lead-halide perovskites. While the main obstacles to the development of lead-halide perovskites are the use of lead and the instability of the structure, halide double perovskites allow multiple metal combinations resulting from the replacement of the lead in single perovskites by two metal-complexes or alternating vacancy metal-complexes in their crystalline structure. Although many advances have already been made in lead-free halide double perovskites, there are still some challenges to be overcome, such as the indirect and high bandgap, and the transitions prohibited by parity, which are intrinsic features of their electronic structure, and result in low energy conversion efficiency and photoluminescence quantum yields as well. Emphasizing the need to review the results of the literature so far, considering the advances and challenges presented, this work involves a systematic and embracing bibliographical research on lead-free halide double perovskites, encompassing central aspects such as their historical evolution, crystalline structure, synthesis methods, challenges faced in the field, optoelectronic properties and perspectives for the development and application of these materials. Leadfree Lead free A2BIBIIIX6 ABIBIIIX A BIBIIIX ABIVX BIVX A2BIVX leadhalide structure metalcomplexes complexes leadfree overcome bandgap parity well far presented evolution methods field A2BIBIIIX

Considering the current environmental problems associated with the growing world demand for energy arising from development and population growth, the need to diversify energy matrices, such as the implementation of solar energy, is highlighted. Thus, it is important to discuss this topic in the school environment, because when they are introduced from childhood to high school, the probability of this orientation being effective is much greater. In this context, educational games have attracted attention as a teaching tool, combining a fun atmosphere with the improvement of learning. This work aimed the production and application of a game in board format representing a dye-sensitized solar cell (CSSC) as a didactic resource in approaching the content of energy conversion. The game allowed an easy visualization of how the energy conversion process is performed by a CSSC. It was presented during the scientific dissemination event “Café com Ciência”, promoted by the Federal University of São João del-Rei, with good results both in gameplay aspects and in helping to understand the theme. The feedback obtained indicates that the game can be a useful tool for students and educators, reaching all its didactic potential and facilitating learning in the face of complex concepts. growth matrices highlighted Thus environment greater context dyesensitized dye sensitized CSSC (CSSC Café Ciência, Ciência , Ciência” delRei, delRei del Rei, Rei del-Rei theme educators concepts

RESUMO Introdução: O objetivo deste artigo foi compreender a importância das “Soft Skills” no contexto do recrutamento e seleção de forma digital. O termo “Soft Skills” significa: atitudes psicológicas e comportamentos construtivos na interação com pessoas e grupos. Nesse contexto foram identificadas as ferramentas que estão sendo utilizadas para avaliá-las e quais são as Soft Skills adequadas nas diversas áreas profissionais em tempos de COVID-19. Métodos: A coleta de dados primários foi realizada através de entrevistas com especialistas que ocorreram em abril de 2020 e de uma survey que foi aplicada entre julho e dezembro de 2020. A amostra, após a limpeza dos dados, resultou em 169 respondentes, permitindo a realização da análise estatística descritiva dos dados. Resultados: Observou-se que as Soft Skills tornaram-se mais estratégicas no panorama da COVID-19. Além disso, ao comparar-se os médicos com especialidade em Cirurgia Plástica em relação às outras profissões, houve maior incidência do grau de concordância total entre os cirurgiões plásticos. Conclusão: Os resultados encontrados podem sugerir que entre os médicos com especialidade em Cirurgia Plástica a importância estratégica das Soft Skills tornou-se ainda mais intensa. Estes resultados, obtidos por meio de uma survey com dados quantitativos, estão em sintonia com a literatura científica apresentada neste artigo, assim como com estudos de organizações corporativas.

ABSTRACT Introduction: This article aims to understand the importance of “Soft Skills “digital recruitment and selection. The term “Soft Skills” means psychological attitudes and constructive behaviors in interacting with people and groups. In this context, the tools used to evaluate them and the appropriate Soft Skills in the various professional areas during COVID-19 were identified. Methods: The primary data collection was carried out through interviews with experts in April 2020, and a survey applied between July and December 2020. After cleaning the data, the sample resulted in 169 respondents, allowing the performing descriptive statistical analysis of the data. Results: It was observed that Soft Skills have become more strategic in COVID-19. In addition, when comparing physicians specializing in Plastic Surgery with other professions, there was a higher incidence of the degree of total agreement among plastic surgeons. Conclusion: The results found may suggest that the strategic importance of Soft Skills has become even more intense among physicians specializing in Plastic Surgery. These results, obtained through a survey with quantitative data, align with this article’s scientific literature and with corporate organizations’ studies.

The present work describes the comparison of the optical and structural properties between CdTe quantum dots (QD) synthesized in water and in the binary solvent (water + glycerin) via one-pot approach synthesis. The optical properties of the nanocrystals obtained with different synthesis parameters were characterized by UV-visible and photoluminescence spectroscopies. The structural chracterization were performed by Fourier transform infrared spectroscopy (FTIR), zeta potential, size-distribution by dynamic light scattering (DLS), X-ray diffraction (XRD), and also by high-resolution transmission electron microscopy (HRTEM). The optical properties of CdTe QD when synthesized in the binary solvent were better, resulting in the increase of photoluminescence quantum yield (Φƒ). The CdTe QD prepared in 120 min, at pH 10.0, in the Cd:Te molar ratio 20:1, using the molar ratio 1:1.5 of Cd:TGA (thioglycolic acid), exhibited a narrow photoluminescence band and enhanced Φƒ for the samples synthesized in a binary solvent in comparison to water solvent (58.4 and 49.5%, respectively).

RESUMO Entre os nanomateriais de carbono, os pontos de carbono (PCs) estão entre os mais atraentes devido as suas interessantes propriedades fotoluminescentes. Os PCs apresentam processo de síntese fácil, possibilidade de funcionalização da superfície, baixa toxicidade, alta solubilidade em água e biocompatibilidade. Devido a isso, suas aplicações na área biomédica e de bioimagem tem se destacado na literatura. Neste trabalho, PCs foram sintetizados por dois métodos diferentes a partir da ovalbumina, o qual é um precursor não tóxico e composto predominantemente por aminoácidos de cadeia curta. Os PCs foram caracterizados por espectroscopias de absorção (UV-Vis), de emissão (fluorescência) e infravermelho (IVTF), além de análise termogravimétrica (ATG). Os PCs foram utilizados como sondas fluorescentes para uma imagem colorida (azul e verde) de células HEK293 e não induziram a morte celular, o que indica que os mesmos são biocompatíveis e não tóxicos para este tipo de células. Dessa forma, os resultados aqui apresentados demonstram que os PCs podem ser considerados potenciais substitutos para corantes comerciais em marcação biológica.

ABSTRACT Among the carbon nanomaterials, carbon dots (CDs) are among the most attractive ones due to their interesting photoluminescent properties. PCs feature easy synthesis process, possibility of surface functionalization, low toxicity, high water solubility and biocompatibility. Because of this, their applications in the biomedical and bioimaging areas has been highlighted in literature. In this work, CDs were synthesized by two different methods using ovalbumin as precursor, which is a nontoxic reactant composed predominantly of short chain amino acids. The CDs were characterized by absorption (UV-Vis), emission (fluorescence), infrared (IRFT) spectroscopies, and thermogravimetric analysis (TGA). The CDs were used as fluorescent probes for multicolor (blue and green) imaging of HEK293 cells and did not induce to cell death, which indicates that the CDs are biocompatible and nontoxic to this type of cells. Therefore, the results presented here demonstrated that CDs can be considered as a potential substitute for commercial dyes in biological images.

Recently, a new class of materials, the Perovskite Nanocrystals, also known as perovskite quantum dots (PQDs) has emerged. Perovskite nanocrystals are promising in optoelectronics due to their quantum confinement properties, narrow photoluminescence bands with short decay times, optically tunable bandgaps, easy surface passivation and high photoluminescent quantum yields. The intense photoluminescence covering the entire visible region of the spectrum can be easily adjusted through the composition and/or the nanocrystals sizes. This paper presents the state-of-the-art of these materials, since their discovery to current research, including their synthesis methods, properties and applications.

RESUMO Este trabalho relata nanopartículas de prata estabilizadas com citrato (AgNPs) sintetizadas pela redução química do íon nitrato com boro-hidreto de sódio, em diferentes pHs (2-9). As AgNPs sintetizadas por este método apresentaram distribuição de tamanho de 5 a 249 nm dependente do pH, conforme determinado por espalhamento dinâmico de luz, além de morfologia esférica, conforme determinado por microscopia eletrônica de transmissão. Na faixa de pH de 3 a 7 ocorreu a agregação das nanopartículas. A distribuição de tamanho, dependendo do pH, foi determinada por espalhamento dinâmico de luz. O potencial Zeta foi determinado e a estabilidade coloidal foi correlacionada com a agregação de nanopartículas em diferentes pHs. A atividade antimicrobiana dependente do tamanho foi avaliada para duas soluções, em que ambas as amostras exibiram atividade antimicrobiana, embora as menores AgNPs sem aglomeração apresentaram propriedades antimicrobianas melhores.

ABSTRACT This paper reports citrate-stabilized silver nanoparticles (AgNPs) synthesized by nitrate ion chemical reduction with sodium borohydride, at different pHs (2–9). The AgNPs synthesized by this method exhibited size distribution from 5 to 249 nm, depending on pH, as determined by dynamic light scattering, and morphology spherical, as determined by transmission electron microscopy. In pH range 3–7 occurred aggregation of the nanoparticles. The size distribution depending on pH was determined by dynamic light scattering. The zeta potential was determined, and the colloidal stability was correlated with nanoparticles aggregation at different pHs. The size-dependent antimicrobial activity was evaluated for two solutions, wherein both samples exhibited antimicrobial activity, although the smallest AgNPs without agglomeration have enhanced antimicrobial properties.

RESUMO Objetivo: descrever a aplicação de intervenção educativa realizada junto a homens trabalhadores e identificar, segundo as percepções destes, os principais resultados obtidos. Métodos: pesquisa descritiva e exploratória, de natureza qualitativa, desenvolvida em um município do Sul do Brasil, com 35 metalúrgicos. Dados foram coletados entre março e junho de 2014, por meio da gravação dos grupos operativos e observação participante. As transcrições e os diários de campo foram submetidos à análise de conteúdo. Resultados: os participantes intensificaram o interesse pela busca por informações sobre saúde, e alguns destes conseguiram implementar mudanças nos estilos de vida, especialmente em relação aos hábitos alimentares e sedentarismo, sendo que o apoio do grupo foi percebido como motivador para as mudanças. Considerações finais: atividades de educação em saúde que abarcam temáticas significativas para os participantes e construídas por um grupo coeso, cujos integrantes se apoiam mutuamente, favorecem a modificação do estilo de vida.

ABSTRACT Objective: todescribe the application of educational intervention performed with working men and identify, according to their perceptions, the main results obtained. Methods: a descriptive and exploratory research, of qualitative nature, developed in a municipality of Southern Brazil, with 35 metallurgists. Data were collected between March and June 2014, through the recording of the operating groups and participant observation. Transcripts and field diaries were submitted to content analysis. Results: participants intensified their interest in the search for health information, and some of them managed to implement changes in lifestyles, especially in relation to eating habits and sedentarism, and the support of the group was perceived as motivating for the changes. Final considerations: health education activities that embrace meaningful themes for participants and are built by a cohesive group whose members support each other, favor lifestyle modification.

RESUMEN Objetivo: describir la aplicación de intervención educativa realizada junto a hombres trabajadores e identificar, según las percepciones de éstos, los principales resultados obtenidos. Métodos: investigación descriptiva y exploratoria, de naturaleza cualitativa, desarrollada em um município del sur de Brasil, con 35 metalúrgicos. Los datos fueron recolectados entre marzo y junio de 2014, por medio de La grabación de los grupos operativos y observación participante. Las transcripciones y los diarios de campo se sometieron alanálisis de contenido. Resultados: los participantes intensificaron el interés por La búsqueda de información sobre salud, y algunos de ellos lograron implementar câmbios em los estilos de vida, especialmente em relación a los hábitos alimentarios y sedentarismo, siendo que el apoyo del grupo fue percibido como motivador para los cambios. Consideraciones finales: actividades de educación em salud que abarcan temáticas significativas para los participantes y construidas por un grupo cohesivo, cuyos integrantes se apoyan mutuamente, favorecen la modificación del estilo de vida.

ABSTRACT Objective: todescribe the application of educational intervention performed with working men and identify, according to their perceptions, the main results obtained. Methods: a descriptive and exploratory research, of qualitative nature, developed in a municipality of Southern Brazil, with 35 metallurgists. Data were collected between March and June 2014, through the recording of the operating groups and participant observation. Transcripts and field diaries were submitted to content analysis. Results: participants intensified their interest in the search for health information, and some of them managed to implement changes in lifestyles, especially in relation to eating habits and sedentarism, and the support of the group was perceived as motivating for the changes. Final considerations: health education activities that embrace meaningful themes for participants and are built by a cohesive group whose members support each other, favor lifestyle modification.

RESUMEN Objetivo: describir la aplicación de intervención educativa realizada junto a hombres trabajadores e identificar, según las percepciones de éstos, los principales resultados obtenidos. Métodos: investigación descriptiva y exploratoria, de naturaleza cualitativa, desarrollada em um município del sur de Brasil, con 35 metalúrgicos. Los datos fueron recolectados entre marzo y junio de 2014, por medio de La grabación de los grupos operativos y observación participante. Las transcripciones y los diarios de campo se sometieron alanálisis de contenido. Resultados: los participantes intensificaron el interés por La búsqueda de información sobre salud, y algunos de ellos lograron implementar câmbios em los estilos de vida, especialmente em relación a los hábitos alimentarios y sedentarismo, siendo que el apoyo del grupo fue percibido como motivador para los cambios. Consideraciones finales: actividades de educación em salud que abarcan temáticas significativas para los participantes y construidas por un grupo cohesivo, cuyos integrantes se apoyan mutuamente, favorecen la modificación del estilo de vida.

RESUMO Objetivo: descrever a aplicação de intervenção educativa realizada junto a homens trabalhadores e identificar, segundo as percepções destes, os principais resultados obtidos. Métodos: pesquisa descritiva e exploratória, de natureza qualitativa, desenvolvida em um município do Sul do Brasil, com 35 metalúrgicos. Dados foram coletados entre março e junho de 2014, por meio da gravação dos grupos operativos e observação participante. As transcrições e os diários de campo foram submetidos à análise de conteúdo. Resultados: os participantes intensificaram o interesse pela busca por informações sobre saúde, e alguns destes conseguiram implementar mudanças nos estilos de vida, especialmente em relação aos hábitos alimentares e sedentarismo, sendo que o apoio do grupo foi percebido como motivador para as mudanças. Considerações finais: atividades de educação em saúde que abarcam temáticas significativas para os participantes e construídas por um grupo coeso, cujos integrantes se apoiam mutuamente, favorecem a modificação do estilo de vida.

This paper reports the synthesis and characterization of ternary CdTe:Zn2+ quantum dots (QDs) passivated with reduced L-glutathione (GSH) dispersed in water. The synthesis was performed through a one-pot approach and their size-dependent optical properties were investigated through steady-state absorption and emission spectroscopies along with the evolving factor analysis/multivariate curve resolution alternating least squares (EFA/MCR-ALS) method. Our results show that the incorporation of Zn2+ ions in CdTe:Zn2+ QDs, during the synthesis time, decreases the CdTe:Zn2+ QDs predominant diameter in the ensemble and increases their size dispersion. In addition, fluorescence quantum yield measurements suggest a reduction in the number of surface defects in CdTe:Zn2+ QDs as compared with CdTe QDs, when both are produced from the same synthesis route.

Solar energy has been considered as an important source of clean and safe energy to overcome the problems associate to the burn of fossil fuels (e.g. climate changes, pollution, health problems, etc.). In the area of photovoltaics, devices that convert solar energy into electricity, perovskites solar cells (PSC) have attracted great attention due to their rapid development, high energy conversion efficiency, diversification of the processing methods and different materials. The fantastic properties of the hybrid perovskite materials, such as high absorption coefficient, direct and tunable bandgap, ambipolar charge carrier, simple preparation, etc., have quoted this technology as one the most important in this century. The rapid development of PSC has provided a significant increase in energy conversion efficiency, which was first reported, in 2009, as 3.8% and now reaches up to 22.10%, according to the National Laboratory of Renewable Energy (NREL). Many studies have been carried out to further increase the efficiency of devices and solve problems as the instability of the material, and the presence of lead, so that the PSC can be applied commercially. This paper presents a review on PSC and the major advances reported in device’s architecture, preparation methods, novel materials and interface engineering.

This work reports a simple and reproducible method for silica-coated multiwalled carbon nanotubes (MWCNTs) nanostructures by the sol-gel method using tetraethoxysilane and 3-aminopropyltriethoxysilane as organosilicon precursors of silica. The synthetic method is based on a noncovalent functionalization of the MWCNTs by the adsorption of the monolayers of different polyelectrolytes, such as poly(allylamine hydrochloride) and poly(sodium 4-styrene sulfonate), which are positively and negatively charged, respectively. The role of these polyelectrolytes is the dispersion and interaction with both the nanotubes and the silicon precursors, influencing directly the silica shell growth. Two different morphology types of the silica-coated multiwalled carbon nanotubes composites were obtained on multiwalled carbon nanotubes. In both case the samples displayed uniformity in the silica layer. Finally, the investigation of the photoluminescence spectra of the samples suggested the presence of some incorrect oxygen bond, or vacancy of oxygen or even presence of nitrogen in the network, which is a typical feature of materials prepared by the sol-gel process at room temperature.

In this work, we have synthesized CdTe quantum dots (QDs) dispersed in an aqueous medium at ambient temperature, and investigated their optical properties. Synthesis of CdTe QDs in the presence of simple amines removed the need for an additional energy source and inert atmosphere, in a simple and inexpensive experimental setup. The use of ammonia or hydrazine promoted nanoparticle growth by kinetic nanocrystal agglomeration in the initial growth stage. These weak electrolytes acted in the electrical double layer during the growth of the nanocrystals. A comparative study on the concentration of hydrazine in the reaction medium helped to investigate their role in nanocrystal growth. Substitution of hydrazine for ethylenediamine and other electrolytes like sodium chloride and ammonium chloride contributed to a better understanding of the mechanism that underlies the use of primary amines in the synthesis of CdTe. The synthesis conditions afforded the highest photoluminescence quantum yield for CdTe QDs prepared at room temperature (27.5%).

Quantum dot solar cells (QDSC) have been subject of extensive research in recent years. QDSC, as a promising alternative to existing solar cells, are among the candidates for next-generation photovoltaic devices that require low cost, high efficiency, so that quantum dots stand out for their unique features and versatile desirable on photovoltaic systems. The rapid development of QDSC provided a significant increase in energy conversion efficiency, which was certified for the first time in 2010 as 2% then being currently as 11.3%, according to the National Renewable Energy Laboratory (NREL). This paper presents a review of the quantum dot-sensitized solar cells and the major advances reported concerning these cells, besides other types of cell architectures involving quantum dots.