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Evaluation of the fatigue resistance and damage modes of lithuim disilicate and resin nanoceramic
No full textFraturas completas ou por delaminação são causas frequentes de insucesso entre coroas unitárias cerâmicas. O uso de materiais à base de resina composta, em contraponto à natureza friável das cerâmicas, parece ser uma alternativa para coroas posteriores, uma vez que apresentam processo de fabricação e reparo simplificados. Este estudo avalia a resistência à fadiga de coroas unitárias monolíticas CAD/CAM de resina composta nanocerâmica e cerâmica reforçada por dissilicato de lítio, bem como os danos causados pela aplicação de carga cíclica. Vinte e seis coroas monolíticas (n=13) foram cimentadas sobre réplicas de resina composta de um molar preparado e submetidas à ciclagem mecânica durante 2 milhões de ciclos, sob carga máxima de 350N à frequência de 2 Hz. Não foram observadas fraturas catastróficas ou fratura coesiva das coroas, resultando em sobrevivência de 100% para os dois materiais avaliados. As coroas foram incluídas em resina epóxi e desgastadas progressivamente à procura de danos. Coroas em resina nanocerâmica apresentaram-se íntegras, com trincas do cone externo, trincas do cone interno e com trincas radiais. As coroas em dissilicato de lítio apresentaram trincas do cone externo e interno, algumas atingindo a superfície interna. Os danos receberam escores de acordo com a severidade. Os dados foram submetidos à análise estatística pelo teste de Mann-Whitney (p =0,462), que não revelou diferenças estatísticas em relação aos danos observados. Concluímos que coroas monolíticas em dissilicato de lítio e resina nanocerâmica podem ser utilizadas na região posterior, pois apresentaram resistência à fadiga equivalente, sem diferença estatística entre os danos apresentados.Bulk fractures or cohesive fractures are frequent complications for ceramic crowns. The use of resin- based materials, in contrast to the brittle nature of ceramics, seems to be an alternative to posterior crowns, since these materials present simplified manufacturing and repair tehniques. This study evaluates the fatigue resistance of monolithic CAD / CAM crowns made of resin nanoceramic and lithium disilicate reinforced ceramic, as well as the damage modes caused by the application of cyclic loading. Twenty-six monolithic crowns (n = 13) were cemented to a composite resin replica of a prepared molar and subjected to cyclic load over 2 million cycles under maximum load of 350N, at a frequency of 2 Hz. The crowns presented no catastrophic failures or cohesive fractures, resulting in survival of 100% for both materials. The crowns were embedded in epoxy resin and gradually grinded for damage analisys. Nanoceramic resin crowns presented no damage, outer cone cracks, inner cone cracks and radial cracks. Lithium disilicate crowns showed outer and inner cone cracks, some of the latter reaching the inner surface. Specimens were scored according to the severity of damage. Data was subjected to Mann-Whitney test (p = 0.462), which revealed no statistical difference. We conclude that lithium disilicate and resin nanoceramic monolithic crowns can be used in the posterior area, since they presented comparable fatigue resistance, with no statistical difference between damage modes
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Comparação entre medidas faciais e dentárias da maxila em mulheres de três etnias
Get PDFOrientador: Prof.ª Dr.ª Raquel Sano Suga TeradaDissertação (mestrado em Odontologia Integrada) - Universidade Estadual de Maringá, 2019RESUMO: Objetivo: Comparar as dimensões dos dentes anteriores da maxila e as distâncias faciais, em mulheres de etnia melanoderma (MEL), leucoderma (LEU) e xantoderma (XAN). Metodologia: Foram selecionadas um total de 90 mulheres entre 18 a 30 anos, residentes em Maringá/PR, das três etnias, as quais foram divididas em três grupos de 30 mulheres cada. Fotografias extrabucais em repouso e perfil direito foram realizadas de cada participante para análise de cinco medidas faciais horizontais: bizigomática (DBZ), interpupilar (DIP), intercantal (DIC), interalar (DIA) e intercomissura (DCM) e seis medidas faciais verticais: comprimento total da face (CT), terço superior (TS), terço médio (TM), terço inferior (TI), segmento subnasal ao estômio (SE) e estômio ao mento (EM). Além disso, foram analisadas sete medidas dentárias horizontais: distância real mesiodistal dos seis dentes anteriores, distância entre os caninos direito ao esquerdo (DCC); e seis medidas da altura dos dentes anteriores no modelo de gesso com paquímetro digital. Os dados foram tabulados no programa Microsoft Office Excel, analisados pelo Software estatístico SigmaPlot 12.0 e calculados via teste de Kruskal-Wallis (? = 0,05) para comparar parâmetros faciais e dentários nas três etnias. A correlação de Spearman foi utilizada para verificar os parâmetros faciais e dentários dentro do estrato etnia. Resultados: Quando os três grupos foram comparados em cada parâmetro, houve diferença estatisticamente significante entre as medidas faciais horizontais DBZ, DIA e DIC, em cinco medidas faciais verticais, com exceção da EM, e na largura e comprimento dos incisivos laterais. Não houve correlação significante entre as medidas faciais e dentárias verticais e horizontais nas três etnias. A exceção foi no grupo LEU, onde houve uma correlação moderada entre os parâmetros DCM e DCC (r=0,517 e p=0,003). Conclusão: O comprimento total da face de LEU é menor, XAN apresentam o terço médio, bem como as distâncias bizigomática e intercantal maiores e, em MEL, o terço superior da face é mais amplo. As três etnias apresentaram referências semelhantes quanto ao tamanho dos dentes anteriores, distâncias interpupilar e intercomissura e o tamanho vertical do lábio inferior ao mento.ABSTRACT: Objectives: Compare the dimensions of the maxillary anterior teeth and facial distances, in women of African-American (MEL), White (LEU) and Asin (XAN) ethnicities. Methodology: A total of 90 women between 18 and 30 years old, residing in Maringá / PR, from the three ethnic groups were selected, which were divided into three groups of 30 women each. Extra-oral photographs at rest and right profile were taken of each participant for analysis of five horizontal facial measures: byzygomatic (DBZ), interpupillary (DIP), intercanthal (DIC), interalar (DIA) and intercomissure (DCM) and six vertical facial measures: total face length (CT), upper third (TS), middle third (TM), lower third (TI), subnasale to stomion lengh (SE) and stomion to menton length (EM). In addition, seven horizontal dental measurements were analyzed: real mesiodistal width of the six anterior teeth, distance between the right and left canines (DCC); and six measurements of the anterior teeth length (C13 to C23) were analyzed in cast with digital caliper. The data were tabulated in the Microsoft Office Excel program, analyzed by statistical software SigmaPlot 12.0 and calculated using the Kruskal-Wallis test (? = 0.05) to compare facial and dental parameters among the three ethnicities. The correlation of Spearman rho was used to verify facial and dental parameters within the ethnic stratum. Results: When the three groups were compared for each parameter, there was a statistically significant difference between horizontal facial measures DBZ, DIA and DIC; in all vertical facial measurements, except for EM and in the width and length of the lateral incisors. There was no significant correlation between vertical and horizontal facial and dental measurements in the three ethnic groups. The exception was in the LEU group, where there was a moderate correlation between the DCM and DCC parameters (r=0.517 and p=0.003). Conclusion: The total length of the LEU face is shorter, XAN presents the middle third, as well as the greater bizygomatic and intercantal distances and, in MEL, the upper third of the face is wider. The three ethnic groups had similar references regarding the size of the anterior teeth, interpupillary and intercomissure distances and the vertical size of the lower lip than the chin.56 f. : il. (algumas color.)
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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