Investiga??o do crescimento topotaxial de hematita em magnetita.

Programa de P?s-Gradua??o em Evolu??o Crustal e Recursos Naturais. Departamento de Geologia, Escola de Minas, Universidade Federal de Ouro Preto.O crescimento topotaxial ? caracterizado quando os cristais de uma nova fase, produto de rea??es qu?micas no estado s?lido, como a oxida??o, se desenvolvem de forma orientada, influenciados pelas orienta??es cristalogr?ficas da fase reagente. Na oxida??o de magnetita para hematita, os cristais de hematita tendem a se desenvolver segundo algumas rela??es topotaxiais, que s?o descritas por rela??es de paralelismo entre planos cristalinos das duas fases. Para esses minerais, o paralelismo entre os planos octa?dricos {111} da magnetita e o plano basal {0001} da hematita ? a condi??o de orienta??o mais comum. A fim de se melhorar o entendimento sobre a transforma??o de fase magnetita-hematita e as rela??es topotaxiais envolvidas neste processo, foram estudados aqui cristais octa?dricos de magnetita parcialmente transformados em hematita. Eles foram retirados de um agregado dr?sico de cristais de magnetita intercrescidos proveniente do distrito de Rodrigo Silva, na cidade de Ouro Preto, por??o sudeste do Quadril?tero Ferr?fero. Os cristais de magnetita foram seccionados paralelamente a um de seus planos octa?dricos {111} e a superf?cie interna foi preparada para an?lises de difra??o de el?trons retroespalhados (EBSD), o que inclui polimento mec?nico e polimento qu?mico-mec?nico com s?lica coloidal. As ?reas com evid?ncias de transforma??o de fase foram selecionadas em microsc?pio ?ptico e posteriormente analisadas por EBSD. As figuras de polo, figuras de polo inversa e mapas de orienta??o evidenciaram uma nova condi??o de orienta??o entre os cristais de magnetita e hematita, em que planos octa?dricos {111} da magnetita est?o paralelos aos planos rombo?dricos {101?1} da hematita, o que nunca foi descrito. Al?m disso, foi identificado o paralelismo entre planos octa?dricos {111} da magnetita e basais {0001} da hematita, e entre planos dodeca?dricos {110} da magnetita e prism?ticos {112?0} da hematita. Nesse contexto, ? poss?vel concluir que a transforma??o de fase ocorre nos planos octa?dricos {111} da magnetita e que existem duas posi??es de crescimento poss?veis para os cristais de hematita em rela??o a um plano {111}. O cristal de hematita pode se desenvolver com o seu plano basal (0001) paralelo ao plano (111) ou ent?o, com o seu plano rombo?drico (101?1) paralelo ao plano (111).Topotaxial growth is typified when the crystals of a new phase, the product of chemical reactions in the solid state, such as oxidation, develop in an oriented way, influenced by the crystallographic orientations of the reactive phase. In the oxidation from magnetite to hematite, hematite crystals tend to develop according to some topotaxial relationships, which are described by parallel relationships between crystalline planes of the two phases. For these minerals, the parallelism between the octahedral planes {111} of magnetite and the basal plane {0001} of hematite is the most common orientation condition. In order to improve the understanding of magnetite-hematite phase transformation and the topotaxial relationships involved in this process, octahedral crystals of magnetite partially transformed into hematite were studied. They were taken from a drusic aggregate of intergrown magnetite crystals that come from the district of Rodrigo Silva, in the city of Ouro Preto, southeastern portion of the Quadril?tero Ferr?fero. The magnetite crystals were sectioned parallel to one of their octahedral planes {111} and the internal surface was prepared for backscattered electron diffraction (EBSD) analyses, which includes mechanical polishing and chemical-mechanical polishing with colloidal silica. The areas with evidence of phase transformation were selected under an optical microscope and subsequently analyzed by EBSD. The pole figures, inverse pole figures and orientation maps showed a new orientation condition between the crystals of magnetite and hematite, in which octahedral planes {111} of magnetite are parallel to the rhombohedral planes {101?1} of hematite, which has never been described. In addition, a parallelism was identified between octahedral planes {111} of magnetite and basal planes {0001} of hematite, and between dodecahedral planes {110} of magnetite and prismatic {112? 0} of hematite. Under these conditions, it is possible to conclude that magnetite-hematite phase transformation occurs in the octahedral planes {111} of the magnetite and that there are two possible growth positions for the hematite crystals in relation to one plane {111}. The hematite crystal can develop with its basal plane (0001) parallel to the plane (111) or else, with its rhombohedral plane (101?1) parallel to the plane (111)

Efeito do tratamento de superfície na resistência e nas características microestruturais e topográficas de uma cerâmica de dissilicato de lítio reforçada com zircônia

The objective of this work was to evaluate the influence of surface treatment on the biaxial flexural strength of zirconia reinforced lithium disilicate ceramics, submitted to mechanical fatigue stress. Were obtained 54 disc-shaped samples of 12 millimeters in diameter by 1.2 millimeters in thickness, divided into three groups (n=18): 5% hydrofluoric acid for 20 seconds and silane (HF20); Hydrofluoric acid 5% for 60 seconds and silane (HF60) and application of ceramic primer (P). Additionally, three samples were included in each group for the purpose of complementary qualitative analyses. The samples were cemented to G10 with Relyx u200 resin cement (3M ESPE) after each surface treatment and were submitted to the mechanical cycling test for 1.0x106 cycles and then to the biaxial flexion test (ISO 6872) immersed in water. The samples assigned to qualitative analyses were submitted to optical profiling, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and subsequently submitted to hardness test and contact angle analysis. The data obtained in this study were submitted to the statistical model of analysis of variance (ANOVA) and Tukey's multiple comparison test. All tests showed statistical differences between the groups used (P<0.05), being the surface treatment with hydrofluoric acid for 20s the most suitable. Thus, it is concluded that the surface treatment alters the roughness, strength, hardness and contact angle of the ceramic involved, and that the surface treatments with better results were the HF20 and P groups.O objetivo desse trabalho foi avaliar a influência do tratamento de superfíciena resistência à flexão biaxial de uma cerâmica de dissilicato de litio reforçada com zircônia, submetida ao estresse por fadiga mecânica. Foram obtidas 54 amostras em formato de disco de 12 milímetros de diâmetro por 1,2 milímetro de espessura, divididos em três grupos (n=18): Ácido fluorídrico 5% por 20 segundos e silano (HF20); Ácido fluorídrico 5% por 60 segundos e silano (HF60) e aplicação de primer cerâmico (P). Adicionalmente, três amostras foram incluídas em cada grupo para fins de análises qualitativas complementares. As amostras foram cimentadas ao G10 com cimento resinoso Relyx u200 (3M ESPE) após cada tratamento de superfície e foram submetidos ao ensaio de ciclagem mecânica por 1,0x106 ciclos e posteriormente ao teste de flexão biaxial (ISO 6872) imerso em agua. As amostras designadas as análises qualitativas foram submetidas à Perfilometría óptica, microscopia eletrônica de varredura (MEV), espectrometria por energia dispersiva (EDS), e posteriomente submetidas ao teste de dureza e análise de ângulo de contato. Os dados obtidos nesse estudo foram submetidos ao modelo estatístico de análise de variância (ANOVA) e ao teste de comparação múltipla de Tukey. Todos os testes demonstraram diferenças e statísticas entre os grupos utilizados (P<0,05), sendo o tratamento de superfície com ácido fluorídrico por 20s o mais indicado. Sendo assim, conclui-se que o tratamento de superfície altera a rugosidade, a resistência, a dureza e o ângulo de contato da cerâmica envolvida, e que os tratamentos de superfície com melhores resultados foram os grupos HF20 e P

Do satisfied customers recommend restaurants? the moderating effect of engagement on social networks on the relationship between satisfaction and eWOM

PurposeAcademics and managers scour to understand which perceived quality factors are paramount to consumers during their restaurant experiences and how they influence their emotions, satisfaction, propensity to loyalty and electronic word-of-mouth (eWOM). However, previous studies are divergent regarding the impacts of satisfaction on eWOM. This survey aims to (a) investigate the impacts of perceived quality by restaurant consumers on positive emotions, negative emotions and satisfaction; (b) verify the impacts of satisfaction on the propensity to loyalty and eWOM; (c) test whether the consumers' behavioural engagement in the SNS (CBE-SNS) moderates the relationship between satisfaction and eWOM.Design/methodology/approachThis survey included 416 university students in Peru who completed an electronic form about their experiences at a la carte restaurants. PLS-SEM tested the hypothetical model based on S-O-R Theory (Mehrabian and Russell, 1974).FindingsThe perceived quality by consumers regarding their restaurant experiences positively impacts satisfaction and positive emotions and negatively affects negative emotions. Satisfaction strongly influences the propensity to loyalty but weakly the eWOM. The CBE-SNS moderates the intensity of the relationship between satisfaction and eWOM.Originality/valueThis study is the first to concomitantly test the relationships between perceived quality, positive and negative emotions, satisfaction, the propensity to loyalty, e-WOM and CBE-SNS. Consumer engagement moderates the relationship between satisfaction and eWOM. Accordingly, to stimulate positive eWOM, restaurants must provide their customers with experiences with high perceived quality, impacting their satisfaction, emotions and propensity for loyalty, and developing strategies to increase CBE-SNS.CENTRUMinfo:eu-repo/semantics/publishedVersio

Burkholderia cepacia, cystic fibrosis and outcomes following lung transplantation: experiences from a single center in Brazil

OBJECTIVES: To evaluate the impact of Burkholderia cepacia complex colonization in cystic fibrosis patients undergoing lung transplantation. METHODS: We prospectively analyzed clinical data and respiratory tract samples (sputum and bronchoalveolar lavage) collected from suppurative lung disease patients between January 2008 and November 2013. We also subtyped different Burkholderia cepacia complex genotypes via DNA sequencing using primers against the recA gene in samples collected between January 2012 and November 2013. RESULTS: From 2008 to 2013, 34 lung transplants were performed on cystic fibrosis patients at our center. Burkholderia cepacia complex was detected in 13 of the 34 (38.2%) patients. Seven of the 13 (53%) strains were subjected to genotype analysis, from which three strains of B. metallica and four strains of B. cenocepacia were identified. The mortality rate was 1/13 (7.6%), and this death was not related to B. cepacia infection. CONCLUSION: The results of our study suggest that colonization by B. cepacia complex and even B. cenocepacia in patients with cystic fibrosis should not be considered an absolute contraindication to lung transplantation in Brazilian centers

Short Assessment of Health Literacy for Portuguese-speaking Adults

OBJETIVO: Desarrollar y validar un instrumento breve para evaluación de alfabetismo en salud en el idioma portugués. MÉTODOS: El instrumento desarrollado consiste de 50 itens que evalúan la capacidad del individuo de pronunciar y comprender términos médicos comunes. Las propiedades psicométricas se evaluaron en una muestra de 226 ancianos brasileños. La validez del constructo se estableció por la correlación con el número de años de escolaridad, relato de alfabetismo funcional y desempeño cognitivo global. La validez discriminatoria fue establecida por la exactitud del instrumento en la detección de alfabetismo en salud inadecuado, definido como la incapacidad de comprender correctamente prescripciones médicas estandarizadas. RESULTADOS: Las correlaciones con los criterios de constructo presentaron magnitud moderada a alta (coeficientes de Spearman = 0,63 a 0,76). El instrumento presentó también consistencia interna satisfactoria (Cronbach = 0,93) y buena confiabilidad examen-reexamen (coeficiente de correlación intra-clase = 0,95). El área bajo la curva característica de operación del receptor para detección de alfabetismo inadecuado fue 0,82. Una versión con 18 itens fue derivada y presentó propiedades psicométricas similares. CONCLUSIONES: El instrumento desarrollado presentó buena validez y consistencia en una muestra de ancianos brasileños y puede ser utilizado en ambientes clínicos o de investigación con la finalidad de detectar alfabetismo en salud inadecuado.OBJECTIVE: To develop and validate a short health literacy assessment tool for Portuguese-speaking adults. METHODS: The Short Assessment of Health Literacy for Portuguese-speaking Adults is an assessment tool which consists of 50 items that assess an individual's ability to correctly pronounce and understand common medical terms. We evaluated the instrument's psychometric properties in a convenience sample of 226 Brazilian older adults. Construct validity was assessed by correlating the tool scores with years of schooling, self-reported literacy, and global cognitive functioning. Discrimination validity was assessed by testing the tool's accuracy in detecting inadequate health literacy, defined as failure to fully understand standard medical prescriptions. RESULTS: Moderate to high correlations were found in the assessment of construct validity (Spearman's coefficients ranging from 0.63 to 0.76). The instrument showed adequate internal consistency (Cronbach's alpha=0.93) and adequate test-retest reliability (intraclass correlation coefficient=0.95). The area under the receiver operating characteristic curve for detection of inadequate health literacy was 0.82. A version consisting of 18 items was tested and showed similar psychometric properties. CONCLUSIONS: The instrument developed showed good validity and reliability in a sample of Brazilian older adults. It can be used in research and clinical settings for screening inadequate health literacy.OBJETIVO: Desenvolver e validar um instrumento breve para avaliação de alfabetismo em saúde na língua portuguesa. MÉTODOS: O instrumento desenvolvido consiste de 50 itens que avaliam a capacidade do indivíduo de pronunciar e compreender termos médicos comuns. As propriedades psicométricas foram avaliadas em uma amostra de 226 idosos brasileiros. A validade de construto foi estabelecida pela correlação com o número de anos de escolaridade, relato de alfabetismo funcional e desempenho cognitivo global. A validade discriminativa foi estabelecida pela acurácia do instrumento na detecção de alfabetismo em saúde inadequado, definido como a incapacidade de compreender corretamente prescrições médicas padronizadas. RESULTADOS: As correlações com os critérios de construto apresentaram magnitude moderada a alta (coeficientes de Spearman = 0,63 a 0,76). O instrumento apresentou ainda consistência interna satisfatória (Cronbach = 0,93) e boa confiabilidade teste-reteste (coeficiente de correlação intraclasse = 0,95). A área sob a curva característica de operação do receptor para detecção de alfabetismo inadequado foi 0,82. Uma versão com 18 itens foi derivada e apresentou propriedades psicométricas similares. CONCLUSÕES: O instrumento desenvolvido apresentou boa validade e consistência em uma amostra de idosos brasileiros e pode ser utilizado em ambientes clínicos ou de pesquisa com a finalidade de detectar alfabetismo em saúde inadequado

A Novel Assay for the Identification of NOTCH1 PEST Domain Mutations in Chronic Lymphocytic Leukemia

Aims. To develop a fast and robust DNA-based assay to detect insertions and deletions mutations in exon 34 that encodes the PEST domain of NOTCH1 in order to evaluate patients with chronic lymphocytic leukemia (CLL). Methods. We designed a multiplexed allele-specific polymerase chain reaction (PCR) combined with a fragment analysis assay to detect specifically the mutation c.7544 7545delCT and possibly other insertions and deletions in exon 34 of NOTCH1. Results. We evaluated our assay in peripheral blood samples from two cohorts of patients with CLL. The frequency of NOTCH1 mutations was 8.4% in the first cohort of 71 unselected CLL patients. We then evaluated a second cohort of 26 CLL patients with known cytogenetic abnormalities that were enriched for patients with trisomy 12. NOTCH1 mutations were detected in 43.7% of the patients with trisomy 12. Conclusions. We have developed a fast and robust assay combining allele-specific PCR and fragment analysis able to detect NOTCH1 PEST domain insertions and deletions

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio