Mode I fracture characterization of human bone using the DCB test

Purpose – Fracture characterization of human cortical bone under pure mode I loading was performed in this work. The purpose of this paper is to validate the proposed test and procedure concerning fracture characterization of human cortical bone under pure mode I loading. Design/methodology/approach – A miniaturized version of the double cantilever beam (DCB) test was used for the experimental tests. A data reduction scheme based on crack equivalent concept and Timoshenko beam theory is proposed to overcome difficulties inherent to crack length monitoring during the test. The application of the method propitiates an easy determination of the Resistance-curves (R-curves) that allow to define the fracture energy under mode I loading from the plateau region. The average value of fracture energy was subsequently used in a numerical analysis with element method involving cohesive zone modelling. Findings – The excellent agreement obtained reveals that the proposed test and associated methodology is quite effective concerning fracture characterization of human cortical bone under pure mode I loading. Originality/value – A miniaturized version of traditional DCB test was proposed for cortical human bone fracture characterization under mode I loading owing to size restrictions imposed by human femur. In fact, DCB specimen propitiates a longer length for self-similar crack propagation without undertaking spurious effects. As a consequence, a R-curve was obtained allowing an adequate characterization of cortical bone fracture under mode I loading

Oxidative Stress, DNA, Cell Cycle/Cell Cycle Associated Proteins and Multidrug Resistance Proteins: Targets of Human Amniotic Membrane in Hepatocellular Carcinoma

The anticancer effects of human amniotic membrane (hAM) have been studied over the last decade. However, the action mechanisms responsible for these effects are not fully understood until now. Previously results reported by our team proved that hAM is able to induce cytotoxicity and cell death in hepatocellular carcinoma (HCC), a worldwide high incident and mortal cancer. Therefore, this experimental study aimed to investigate the cellular targets of hAM protein extracts (hAMPE) in HCC through in vitro studies. Our results showed that hAMPE is able to modify oxidative stress environment in all HCC cell lines, as well as its cell cycle. hAMPE differently targets deoxyribonucleic acid (DNA), P21, P53, β-catenin and multidrug resistance (MDR) proteins in HCC cell lines. In conclusion, hAMPE has several targets in HCC, being clear that the success of this treatment depends of a personalized therapy based on the biological and genetic characteristics of the tumor

Genetic parameters and selection strategies for soybean genotypes resistant to the stink bug-complex

Soybean genotypes resistant to stink bugs are derived from complex breeding processes obtained through indirect selection. The aim of the present work was to estimate genetic parameters for guiding selection strategies towards resistant genotypes, based on those traits associated with responses to pod-attacking stink bugs, such as the grain filling period (GFP), leaf retention (LR), percentage index of pod damage (PIPD) and percentage of spotted seeds (PSS). We assessed the parental lines IAC-100 (resistant) and FT-Estrela (susceptible), the progenies F2 and F 4 , 30 progenies F 2:3 , 30 progenies BC 1 F 2:3 and 30 progenies BC 2 F 2:3 , besides the cultivars BRS Celeste and MGBR-46 (Conquista). Three field experiments, using randomized complete block design with three replications, were installed in Goiânia-GO, in the 2002/03 season. Each experiment consisted of 36 treatments (6 common and 30 regular). Heritability estimates were: 74.6 and 36.1 (GFP); 51.9 and 19.9 (LR); 49.6 and 49.6 (PIPD) and 55.8 and 20.3 (PSS), in both the broad and narrow senses, respectively. Based on these results, we concluded that the best strategy for obtaining stink bug-resistant genotypes consists of selecting the PIPD trait in early generations (F 3 or F 4 ), followed by selection for the GFP, LR and PSS traits in generations with higher endogamy levels

Does the acidity of self-etching primers affect bond strength and surface morphology of enamel?

Purpose: This study examined the ultrastructure and microtensile bond strengths (TBS) of self-etching (with different acidity) and conventional adhesive systems bonded to unground enamel. Materials and Methods: Resin composite (Filtek Z250) buildups were bonded to unground enamel surfaces of third molars after adhesive application with the following materials: Clearfil SE Bond (CSE); Optibond Solo Plus Self-Etch (OP); Tyrian Self Priming Etching (TY), and the controls Scotchbond Multi-Purpose Plus (SBMP) and Single Bond (SB). Six teeth were assigned to each material. After storage in water for 24 h at 37 degrees C, the bonded specimens were sectioned into beams of approximately 0.8 mm(2) and subsequently subjected to mu TBS testing at a crosshead speed of 0.5 mm/min. The average values were subjected to one-way ANOVA (alpha = 0.05). The effect of surface conditioning of each material was observed under scanning electron microscopy (SEM). Results: The highest resin-enamel bond strength was observed for SBMP (22.7 +/- 5.2) and SB (26.7 +/- 5.2 MPa). The lowest mean bond strengths were 10.9 +/- 3.2 and 7.8 +/- 1.5 MPa for TY and OP, respectively. CSE showed an intermediate performance (18.7 +/- 4.6 MPa). An overall increase in porosity was evident along the entire enamel surface treated with the self-etching primers; however, no selective demineralization similar to that with 35% phosphoric acid was observed. Conclusion: The highest bond strength means and the more retentive etching pattern were observed for the two-step etch-and-rinse adhesives. Among the self-etching systems studied, Clearfil SE Bond should be preferred.82758

Stringy effects in black hole decay

We compute the low energy decay rates of near-extremal three(four) charge black holes in five(four) dimensional N=4 string theory to sub-leading order in the large charge approximation. This involves studying stringy corrections to scattering amplitudes of a scalar field off a black hole. We adapt and use recently developed techniques to compute such amplitudes as near-horizon quantities. We then compare this with the corresponding calculation in the microscopic configuration carrying the same charges as the black hole. We find perfect agreement between the microscopic and macroscopic calculations; in the cases we study, the zero energy limit of the scattering cross section is equal to four times the Wald entropy of the black hole.Comment: 32 page

Teste à cabeceira no HFF: a última oportunidade para evitar transfusões ABO incompatíveis

Introdução: O teste à cabeceira é utilizado desde há cerca de 12 anos no Hospital Fernando Fonseca (HFF). Este teste é um teste realizado imediatamente antes da transfusão para a determinação do grupo ABO do doente à cabeceira do doente a transfundir. Este teste (cartão Medtro NK4®Medtro GmbH) permite, de uma maneira rápida e fácil (aproximadamente 2 minutos) confrontar o resultado obtido com o resultado do grupo obtido na amostra estudada pelo Serviço de Sangue e Medicina Transfusional. Este resultado deverá ser o mesmo. O resultado do teste é ainda comparado com o grupo da unidade de concentrado eritrocitário (CE) a transfundir, determinan-do assim a sua compatibilidade com o grupo do receptor. O teste é constituído por um soro anti-A (clone Birma-1) e outro anti-B (clone-LB2), sendo de execução fácil e o seu preço é convidativo (1,57€/teste). Os enfermeiros que realizam o teste devem registar na ficha de confirmação positiva da transfusão (CPT) que o efectuaram e se está ou não conforme. A ficha de CPT faz também, como o teste à cabeceira, parte integrante do sistema de hemovigilância implementado no Hospital. Objetivo Analisar a efectiva implementação do teste à cabeceira e da confirmação positiva da transfusão no nosso hospital e a sua contribuição para o aumento da segurança transfusional. Material e métodos: Analisámos as fichas de confirmação positiva da transfusão que foram entregues no nosso serviço entre 21 de Novembro de 2012 e 20 de Setembro de 2014, num total de 17284 e que incluem o registo dos testes à cabeceira efetuados antes da transfusão de CEs. Resultados: Durante o período analisado, foram transfundidas 23954 unidades de CE correspondentes a 17284 pedidos. Foram registados 16195 testes à cabeceira, ficando por registar 1089 (6,3%), ficando por se saber se estes não foram efectuados ou simplesmente não registada a sua execução. Todas as fichas de confirmação positiva da transfusão, relativas aos pedidos efectuados, foram devolvidas ao serviço (100%). Conclusão: A confirmação positiva da transfusão está, na nossa opinião, totalmente implementada no HFF, permitindo o registo, rastreabilidade e arquivo dos dados relativos à transfusão de todos os componentes eritrocitários transfundidos aos doentes. A fácil execução e a rapidez na obtenção de resultados do teste à cabeceira permitiu uma grande adesão à sua execução pelos enfermeiros responsáveis pela transfusão (93,7%). É, por isso, imprescindível continuar o reforço da formação em Segurança Transfusional, já em curso no Hospital, para que o risco de transfusão de componentes ABO incompatíveis se aproxime do zero, tendo o Hospital classificado esta possibilidade como "Não Evento"