Síntesis de kesterita Cu2ZnSn(S,Se)4 mediante métodos de hot-injection y solvotermal

En el presente trabajo se han sintetizado compuestos con estructura de kesterita Cu2ZnSn(S,Se)4 mediante métodos de síntesis “hot-injection” y solvotermal. Se ha analizado la efectividad de ambos procedimientos sobre las propiedades físico-químicas del material. Paralelamente, se ha estudiado la influencia de precursores y disolventes sobre la reactividad y la morfología del sistema. Los materiales desarrollados se han caracterizado estructural y microestructuralmente.Kesterite solid solution of Cu2ZnSn(S,Se)4 have been synthesized by “hot-injection” and solvothermal methods. The procedure effectiveness that affect to the physical and chemical properties of the final material have been analyzed. The influence of different raw materials and solvents has been investigated in order to improve the preparation procedure. The materials have been characterized structurally and morphologically

Easy and low-cost aqueous precipitation method to obtain Cu2ZnSn(S, Se)4 thin layers

An easy method to obtain kesterite Cu2ZnSn(Se1-x,Sx)4 (CZTSSe) solid solution as an absorber for thin film photovoltaic solar cells is discussed in this report. Particular emphasis is directed toward the procedure´s steps of the CZTSSe preparation, as well as its structure and properties. For the preparation of CZTSSe an easy, low-cost and sustainable aqueous precipitation method that included chemical transformations of metal selenite precipitate, its reduction to metal selenides and further crystallization of kesterite, is applied. This procedure is more viable as avoids the use of selenization treatment and thus generation of toxic vapors and employs water as a solvent instead of organic compounds. In addition, the proposed procedure is very attractive way of preparation for industrial large-scale fabrication of the most promising absorber candidates for photovoltaic thin film solar cells. Kesterite CZTSSe solid solution has been prepared and characterized in terms of chemical composition, structural and morphological transformations, as well as optical and electrical properties, confirming the viability and effectiveness of the applied process. The optimal electrical parameters obtained of the device are 21.5 mA/cm2, 532 mV, 42.8%., and 4.9% to short circuit current (Jsc), open circuit voltage (Voc), fill factor (FF), and efficiency (Eff.) respectively. Detailed description of each procedure steps and full characterization of the products, starting from as-prepared, intermediate and final compound is also exposed that could be very useful for any experimental scientist.The authors would like to acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness under the programs RETOS-COLABORACION (RTC-2014–2294-3) and RETOS-INVESTIGACIÓN (ENE2013-49136-C4-2-R). We also appreciate the characterization assistance of Central Service of Scientific Instrumentation (SCIC) at the University Jaume I and Catalonia Institute for Energy Research (IREC) for them help in the Raman measurements and solar cell asembly. R. Martí would like to acknowledge the economic support of the FPI-UJI grand (Formación del personal investigator-Universidad Jaume I)

Influence of plasma nitriding with a nitrogen rich gas composition on the reciprocating sliding wear of a DIN 18MnCrSiMo6-4 steel

In this study, the sliding wear of a DIN 18MnCrSiMo6-4 continuous cooling bainitic steel plasma nitrided with a nitrogen rich gas composition was investigated. To evaluate the influence of processing time and temperature on mechanical and microstructural characteristics of nitrided layer, the samples were nitrided at 400, 450, 500 and 550 °C for 3, 6 and 9 h. The produced nitrided layers were characterized concerning the microstructure, phase composition, microhardness and surface roughness. The samples were tested by ball-on-flat reciprocating dry sliding for friction coefficient and wear analysis. The tests were stopped after a given damage criteria involving the rapid growth of the friction coefficients and wear. The correlation of the different treatment parameters and resulting case depths and surface hardness with sliding distance at the time of microcracks formation or delamination of the surface layer was evaluated statistically by the analysis of variance (ANOVA). The plasma nitrided samples at 550 °C showed better wear performances in the ball-on-flat tests than the other groups investigated, since these samples have a thicker compound layer and diffusion zone higher than the other conditions investigated. In general, the beginning wear is slower because of the hardest region of the compound layer

Neurosensory analysis of tooth sensitivity during at-home dental bleaching: a randomized clinical trial

Objective: The objective of this study was to evaluate dental sensitivity using visual analogue scale, a Computerized Visual Analogue Scale (CoVAS) and a neurosensory analyzer (TSA II) during at-home bleaching with 10% carbamide peroxide, with and without potassium oxalate. Materials and Methods:Power Bleaching 10% containing potassium oxalate was used on one maxillary hemi-arch of the 25 volunteers, and Opalescence 10% was used on the opposite hemi-arch. Bleaching agents were used daily for 3 weeks. Analysis was performed before treatment, 24 hours later, 7, 14, and 21 days after the start of the treatment, and 7 days after its conclusion. The spontaneous tooth sensitivity was evaluated using the visual analogue scale and the sensitivity caused by a continuous 0°C stimulus was analyzed using CoVAS. The cold sensation threshold was also analyzed using the TSA II. The temperatures obtained were statistically analyzed using ANOVA and Tukey's test (α=5%). Results: The data obtained with the other methods were also analyzed. 24 hours, 7 and 14 days before the beginning of the treatment, over 20% of the teeth presented spontaneous sensitivity, the normal condition was restored after the end of the treatment. Regarding the cold sensation temperatures, both products sensitized the teeth (p<0.05) and no differences were detected between the products in each period (p>0.05). In addition, when they were compared using CoVAS, Power Bleaching caused the highest levels of sensitivity in all study periods, with the exception of the 14th day of treatment. Conclusion: We concluded that the bleaching treatment sensitized the teeth and the product with potassium oxalate was not able to modulate tooth sensitivity

EFICÁCIA DE DIFERENTES TIPOS DE ESCOVAS DENTAIS NA REMOÇÃO DO BIOFILME BUCAL

Devido ao fato do método mais indicado para remoção do biofilme bucal ser o mecânico, com a utilização da escova dental, buscou-se verificar as características das escovas dentais mais eficazes, como características do cabo em relação à haste e à cabeça, formato e tipo das cerdas, considerando tamanho e disposição dos tufos, bem como comparar a eficácia das escovas manuais e elétricas. O estudo foi realizado com 28 crianças em uma escola municipal da cidade de Umuarama- PR.  Foram utilizados quatro tipos de escovas: escova de haste reta com cerdas regulares; escova de haste angulada com cerdas regulares; escova de haste angulada com cerdas irregulares e escova elétrica. Foram realizados a evidenciação do biofilme e o Índice de Higiene Oral Simplificado (IHOS) antes e após a escovação. Os diferentes tipos de escovas foram avaliados de acordo com a diferença entre o percentual de biofilme antes e após a escovação, bem como em relação à redução da classificação do IHOS. Nas diferentes análises, a escova de haste reta apresentou os melhores resultados. Em contrapartida, a escova elétrica apresentou resultados menos satisfatórios. Podemos concluir que todas as escovas dentárias apresentaram potencial de redução do biofilme dentário, independentemente das características de sua haste, cerdas ou manuseio (manual ou elétrico). Contudo, os melhores resultados foram atribuídos à escova que apresenta a haste reta, que também possui cerdas regulares

Eritema elevatum diutinum como diagnóstico diferencial das doenças reumatológicas: relato de caso

Erythema elevatum diutinum is a chronic and rare cutaneous leukocytoclastic vasculitis, characterized by red, purple and yellow papules, plaques and nodules, distributed symmetrically on the extensor surfaces of the limbs. It is associated with several autoimmune, neoplastic and infectious processes, mainly hematological malignancies in about 30% of the cases. Joint pain and arthritis are frequent symptoms, affecting approximately 40% of the patients, indicating the need for its inclusion in the differential diagnosis of rheumatic diseases, chiefl y the other presentations of leukocytoclastic vasculitis, which are characterized by the combination of rheumatic manifestations and peculiar cutaneous lesions. We report the case of an 18-year-old female patient who developed erythema elevatum diutinum and whose diagnosis was based on the morphologic characteristics, the distribution pattern of the cutaneous lesions and the histopathological fi ndings of leuko- cytoclastic vasculitis. The major systemic symptom was severe arthritis.O eritema elevatum diutinum é uma vasculite leucocitoclástica cutânea crônica e rara, caracterizada por pápulas, placas e nódulos vermelhos, purpúreos e amarelados, distribuídos simetricamente sobre as superfícies extensoras das extremidades. Está associado a vários processos autoimunes, neoplásicos e infecciosos, principalmente malignidades hematológicas (cerca de 30% dos casos). Artralgia e artrite são sintomas frequentes, que afetam por volta de 40% dos pacientes, o que indica a necessidade de sua inclusão no diagnóstico diferencial das doenças reumatológicas, principalmente se em conjunto com outras apresentações da vasculite leucocitoclástica, caracterizadas pela combinação de manifestações reumáticas com alterações cutâneas características. Descrevemos o caso de uma paciente de 18 anos que desenvolveu eritema elevatum diutinum, cujo diagnóstico baseou-se nas características morfológicas, no padrão de distribuição das lesões cutâneas e nos achados histopatológicos de vasculite leucocitoclástica. O principal sintoma sistêmico era uma artrite severa

Microestrutura e Propriedades de Desgaste do Aço Bainítico de Resfriamento Contínuo DIN 18MnCrSiMo6-4 Nitretado a Plasma em Diferentes Temperaturas

Os novos aços bainíticos de resfriamento contínuo (CCBS) são uma excelente alternativa quando se requer elevada dureza, tenacidade e resistência à fadiga. Contudo, estima-se que a taxa de desgaste dos CCBS seja insuficiente para aplicação em componentes com alta solicitação mecânica, sendo necessário aprimorar suas propriedades de superfície. O objetivo deste estudo é o de analisar os efeitos da nitretação a plasma sobre à microestrutura e propriedades de desgaste do aço bainítico de resfriamento contínuo DIN18MnCrSiMo6-4. Portanto, tratamentos com duração de 6 horas foram conduzidos com pressão de 3 mbar, mistura gasosa composta por 76% N2 + 24% H2, e temperaturas de 400, 450, 500 e 550 °C, respectivamente. As amostras foram analisadas através de microscopia eletrônica de varredura, difração de raios-X, microdureza e ensaios de desgaste por deslizamento recíproco. Nas condições investigadas, foi possível obter uma camada de compostos e atingir um aumento de até 393% na dureza superficial, entretanto, o uso de temperaturas mais elevadas durante os tratamentos favoreceu a formação de camadas mais profundas. Em todas as amostras nitretadas, constatou-se a formação predominante da fase de nitretos ε-Fe2-3N e, em menor quantidade, da fase de nitretos γ’-Fe4N. Nos ensaios de deslizamento recíproco houve diminuição do desgaste das amostras nitretadas na temperatura de 550°C. Palavras-chave: Aços Bainíticos de Resfriamento Contínuo, Nitretação a Plasma, Microestrutura e Propriedades de Desgaste

Critical oral diseases in rheumatoid arthritis: knowing, understanding and preventing / Lesões bucais importantes na artrite reumatoide: conhecer, compreender e prevenir

Rheumatoid Arthritis (RA) is a chronic multifactorial disease characterized by inflammation of the synovial membranes that line the joints and affect 1% of the world population. This narrative review aims to discuss a highlight mechanisms about the main oral manifestations in patients with rheumatoid arthritis researching epidemiological data. This narrative review was performed by searching the literature on the MEDLINE / PubMed databases for articles in English focused on oral diseases in patients with RA. Scientific studies show that RA patients are at high risk of developing oral changes, for example, periodontal disease (PD), Sjögren's syndrome (SS), xerostomia and temporomandibular joint disorder (TMD). There is a complex interrelation between oral diseases and RA, with sufficient scientific evidence to assure that there is an association that is bidirectional and impacts the pathogenesis and evolution of these conditions. This bidirectional connection with effects on the inflammatory profile of individuals reinforces the need for future clinical studies that confirm the effectiveness of prevention and early diagnosis protocols for rheumatological disease and the main associated oral diseases

A Plant Proteinase Inhibitor from Enterolobium contortisiliquum Attenuates Pulmonary Mechanics, Inflammation and Remodeling Induced by Elastase in Mice

Proteinase inhibitors have been associated with anti-inflammatory and antioxidant activities and may represent a potential therapeutic treatment for emphysema. Our aim was to evaluate the effects of a plant Kunitz proteinase inhibitor, Enterolobium contortisiliquum trypsin inhibitor (EcTI), on several aspects of experimental elastase-induced pulmonary inflammation in mice. C57/Bl6 mice were intratracheally administered elastase (ELA) or saline (SAL) and were treated intraperitoneally with EcTI (ELA-EcTI, SAL-EcTI) on days 1, 14 and 21. On day 28, pulmonary mechanics, exhaled nitric oxide (ENO) and number leucocytes in the bronchoalveolar lavage fluid (BALF) were evaluated. Subsequently, lung immunohistochemical staining was submitted to morphometry. EcTI treatment reduced responses of the mechanical respiratory system, number of cells in the BALF, and reduced tumor necrosis factor- (TNF-), matrix metalloproteinase-9 (MMP-9), matrix metalloproteinase-12 (MMP-12), tissue inhibitor of matrix metalloproteinase (TIMP-1), endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS)-positive cells and volume proportion of isoprostane, collagen and elastic fibers in the airways and alveolar walls compared with the ELA group. EcTI treatment reduced elastase induced pulmonary inflammation, remodeling, oxidative stress and mechanical alterations, suggesting that this inhibitor may be a potential therapeutic tool for chronic obstructive pulmonary disease (COPD) management.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Univ Sao Paulo, Sch Med, Dept Clin Med, BR-01246903 Sao Paulo, BrazilHosp Sirio Libanes, Phys Therapy Dept, BR-01308050 Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Biosci, BR-09972270 Diadema, BrazilUniv Fed Sao Paulo, Dept Biochem, BR-09972270 Diadema, BrazilUniv Fed Sao Paulo, Dept Biosci, BR-09972270 Diadema, BrazilUniv Fed Sao Paulo, Dept Biochem, BR-09972270 Diadema, BrazilWeb of Scienc

Prognóstico de Eritroblastose Fetal em Crianças Prematuras / Prognosis of Fetal Erythroblastosis in Premature Children

INTRODUÇÃO: A doença hemolítica do feto e do recém-nascido (HDFN), também conhecida como HDFN aloimune ou eritroblastose fetal, é causada pela destruição dos glóbulos vermelhos do recém-nascido ou do feto pelos anticorpos maternos imunoglobulina G, que ocasiona hiperbilirrubinemia. O presente trabalho tem como objetivo apresentar uma revisão narrativa literária sobre o prognóstico da eritroblastose fetal em crianças prematuras. METODOLOGIA: Trata-se de uma revisão narrativa literária que utilizou as bases de dados SCIELO, LILACS, MEDLINE e PubMed. Como critérios de inclusão, selecionou-se artigos nos idiomas inglês, português e espanhol que estivessem disponíveis na íntegra. RESULTADOS:  Foram selecionados 28 artigos para análise. Verificou-se que a causa da doença é a incompatibilidade de grupos sanguíneos entre mãe e feto, sendo que na maioria dos casos há envolvimento dos antígenos dos grupos Rh e ABO. DISCUSSÃO: Com o excesso dos níveis da bilirrubina em neonatos prematuros podem apresentar reações adversas tendo em vista a neurotoxicidade e tratamentos excessivos com fototerapia e exsanguíneo-transfusão. CONCLUSÃO: Pode-se concluir que a HDFN é uma doença hemolítica grave, que pode ocasionar morte do bebe durante a gravidez ou no parto, ou mesmo manifestações neurotóxicas, necessitando de rápido diagnóstico e tratamento.