Supraspinatus (SSP) tendon tear leads to intramuscular fat accumulation in the SSP muscle and the mechanisms are currently unknown. The purpose of this study was to investigate changes in vascularization of the SSP muscle and the relationship to intramuscular fat accumulation following SSP tendon detachment with or without reattachment. One hundred and six rabbits underwent SSP tendon detachment. In groups of ten, thirty rabbits were sacrificed 4, 8, and 12 weeks following detachment. Forty rabbits underwent detachment and immediate reattachment and were sacrificed in groups of ten following 0, 1, 2, and 6 weeks of healing. In groups of twelve, the remaining thirty-six rabbits underwent SSP tendon reattachment 4, 8, and 12 weeks after detachment and were sacrificed 12 weeks later. Vascularization was quantified in each specimen using CD31 immunohistochemistry. Four weeks after SSP tendon detachment, there was an increase in vascularization of the distal SSP muscle that reached significance after 12 weeks of detachment (p=0.024). We found that vascularization was positively correlated with intramuscular fat accumulation after detachment only (r=0.29; p=0.008). After SSP tendon reattachment, immediate or delayed, the correlation between vascularization and intramuscular fat accumulation was not observed. Microscopically, some SSP muscle vascular structures in the reattachment group had thicker vascular walls which were further quantified using αSMA immunohistochemistry. The delayed reattachment group showed an increase in vascular wall thickness in the distal portion of the SSP muscle at 4+12 (p=0.012) and 12+12 (p=0.012) weeks and in the proximal portion at 4+12 (p=0.024) weeks. Further investigation is required to demonstrate a cause/effect relationship between increased vascularization and intramuscular fat accumulation in the context of rotator cuff tear and success of surgical repair.

Made available in DSpace on 2014-10-09T12:49:00Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:47Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Este trabalho tem como objetivo realizar um estudo preliminar da influência da espessura na vida em fadiga de arames de aço deformados a frio. A espessura original dos arames é de 5mm e foi criada uma segunda condição, com diminuição dessa espessura para 2,5mm. Para avaliar o comportamento em fadiga do material, foram realizados testes de fadiga por carregamento em flexão com o intuito de comparar a diferença de desempenho entre as espessuras de 5 e 2,5mm. Os resultados mostraram que para os níveis de carregamento mais altos impostos sobre as amostras (1000 MPa) a condição com 2,5mm de espessura apresenta uma tendência de melhora na resistência à fadiga, essa tendência de aumento acentua-se à medida que os níveis de solicitação diminuem. A condição com espessura de 2,5mm apresentou também tendência de aumento do limite de fadiga. / The aim of this work is to make a preliminary study about the influence of thickness effect on the fatigue behavior of cold drawing steel strips. The original component’s thickness is 5mm and was carried a decrease of this thickness to 2,5mm. To evaluate the fatigue performance, was obtained bending load fatigue curves to compare the performance of the samples with 5 and 2,5 mm of thickness. The results shown that for higher load levels the fatigue strength and endurance limit had presented a tendency of increase for the 2,5mm thickness condition.

Made available in DSpace on 2014-10-09T12:49:00Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:47Z (GMT). No. of bitstreams: 0 / Neste trabalho é descrito um procedimento para a determinação quantitativa da espessura e composição química de filmes finos, por fluorescência de raios X por dispersão de comprimento de onda (WDXRFS), utilizando-se o método de Parâmetros Fundamentais (FP). Este método foi validado dentro dos padrões de garantia de qualidade e aplicado as amostras de Al, Cr, TiO2, Ni, ZrO2 (monocamada) e Ni/Cr (duplacamada) sobre vidro; Ni sobre aço inoxidável e zinco metálico e TiO2 sobre ferro metálico (monocamada), as quais foram preparadas por deposição física de vapor (PVD). Os resultados das espessuras foram comparados com os métodos de Absorção (FRX-A) e Retroespalhamento de Rutherford (RBS), demonstrando a eficiência do método de parâmetros fundamentais. As características estruturais das amostras foram analisadas por difração de raios X (DRX) e mostraram que os mesmos não influenciam nas determinações das espessuras. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

In this study, we present results from teleseismic receiver functions, in order to investigate the crustal thickness and Vp/Vs ratio beneath northern Peru. A total number of 981 receiver functions were analyzed, from data recorded by 28 broadband seismic stations from the Peruvian permanent seismic network, the regional temporary SisNort network and one CTBTO station. The Moho depth and average crustal Vp/Vs ratio were determined at each station using the H-k stacking technique to identify the arrival times of primary P to S conversion and crustal reverberations (PpPms, PpSs + PsPms). The results show that the Moho depth correlates well with the surface topography and varies significantly from west to east, showing a shallow depth of around 25 km near the coast, a maximum depth of 55-60 km beneath the Andean Cordillera, and a depth of 35-40 km further to the east in the Amazonian Basin. The bulk crustal Vp/Vs ratio ranges between 1.60 and 1.88 with the mean of 1.75. Higher values between 1.75 and 1.88 are found beneath the Eastern and Western Cordilleras, consistent with a mafic composition in the lower crust. In contrast values vary from 1.60 to 1.75 in the extreme flanks of the Eastern and Western Cordillera indicating a felsic composition. We find a positive relationship between crustal thickness, Vp/ Vs ratio, the Bouguer anomaly, and topography. These results are consistent with previous studies in other parts of Peru (central and southern regions) and provide the first crustal thickness estimates for the high cordillera in northern Peru.

Isostatic equilibrium is commonly defined as the state achieved when there are no lateral gradients in hydrostatic pressure, and thus no lateral flow, at depth within the lower viscosity mantle that underlies a planetary body's outer crust. In a constant-gravity Cartesian framework, this definition is equivalent to the requirement that columns of equal width contain equal masses. Here we show, however, that this equivalence breaks down when the spherical geometry of the problem is taken into account. Imposing the "equal masses" requirement in a spherical geometry, as is commonly done in the literature, leads to significant lateral pressure gradients along internal equipotential surfaces and thus corresponds to a state of disequilibrium. Compared with the "equal pressures" model we present here, the equal masses model always overestimates the compensation depth-by similar to 27% in the case of the lunar highlands and by nearly a factor of 2 in the case of Enceladus. Plain Language Summary "Isostasy" is the principle that, just as an iceberg floats on the water, crustal rocks effectively float on the underlying higher density mantle, which behaves essentially like a fluid on geologic timescales. Although there are subtle inconsistencies among the various ways isostasy can be defined, they have not been historically problematic for bodies like the Earth, where the crust is thin compared with the overall radius. When the thickness of the crust is a nonnegligible fraction of a planetary body's radius, however, it becomes important to take the spherical geometry into account. In this case, the inconsistencies in the definitions can lead to significant discrepancies. Here we argue that one of the most commonly used approaches, which requires equal width columns to contain equal masses, always results in overestimating the crustal thickness. In particular, we suggest that the lunar and Martian highlands crustal thickness may have been overestimated by similar to 27% and similar to 10%, respectively, and that the ice shell thickness for Saturn's small icy moon Enceladus may have been overestimated by nearly a factor of 2.

Abstract The cholesteryl ester transfer protein (CETP) is a plasma protein that transfers cholesteryl esters and triglycerides between plasma lipoproteins. Humans with a genetic CETP deficiency have high plasma high density lipopoprotein cholesterol (HDL-C) levels, whereas the CETP transgene lowers plasma HDL-C levels in mice. The role of CETP in the development of atherosclerosis is unclear due to the controversial results of many human and animal studies. The present research was designed to investigate the CETP gene as a candidate gene in the regulation of plasma HDL-C levels and the development of atherosclerosis in humans. The CETP gene was screened for mutations and polymorphisms associated with these traits in a well-characterized, homogenous population sample of 515 men and women and in a sample of 115 men with low HDL-C levels and coronary heart disease (CHD). Using polymerase chain reaction and single-strand conformation polymorphism analysis (PCR-SSCP), three polymorphic sites were found (A373P, I405V, R451Q) in the exons of the CETP gene, one in intron 9 and one in the 3'untranslated region of the CETP gene. In addition, the genotypes of a functional promoter polymorphism were determined. The V405 allele was associated with lower plasma CETP activity in the whole population sample, and the Q451 allele and the P373 allele were associated with higher plasma CETP activity in men, whereas the genotypes of the promoter polymorphism were not significantly associated with plasma CETP activity. The genotypes of the CETP gene explained about 20 % of the variation of plasma CETP activity in men. The CETP gene polymorphisms were found to be a minor regulator of plasma HDL-C levels, and these associations interacted with alcohol consumption, sex and triglyceride levels. The strongest association was detected between the promoter polymorphism and HDL-C levels in women. The variation at the CETP gene locus explained about 8 % of the variation in plasma HDL-C levels in women, but less than 1 % in men. CETP gene polymorphisms (A373P, I405V and R451Q) were associated with carotid intima-media thickness, explaining about 6 % of the variation in men and 4 % in women. However, none of the polymorphisms were associated significantly with the CHD risk. In conclusion, the CETP gene was found to be polymorphic and a minor regulator of plasma HDL-C levels and the development of atherosclerosis.

Magister Chirurgiae Dentium (MChD) / Oral lichen planus (OLP) is a T-cell mediated chronic inflammatory disease with different clinical types that remains inscrutable in respect of its pathogenetic mechanisms and effective therapy. Increased apoptosis may influence the histopathological criteria of oral lichen planus (decrease in thickness of the epithelium and band of inflammatory infiltrate). Null hypothesis: The apoptotic rate does not correlate with a decrease in the epithelial thickness as well as the thickness of the band of inflammatory infiltrate in OLP. Aim: The present study aims to quantify apoptotic activity and to correlate the apoptotic rate with epithelial thickness as well as thickness of the inflammatory infiltrate of OLP cases diagnosed at Tygerberg Hospital from 2006 – 2015. Further, the epithelial thickness and thickness of the inflammatory infiltrate were also assessed for their association, if any. Materials and Methods: The study sample comprised 17 diagnostically verified cases of OLP. Sections stained with Haematoxylin and Eosin (H&E) were used to identify and count the number of apoptotic cells as well as measure the thickness of epithelium and the thickness of the lymphocytic inflammatory infiltrate by using software morphometric analysis (Zen Blue lite 2012). Statistical analysis was applied to analyse the correlation between apoptotic cells and histopathological features of OLP. Results: The present study's results showed no statistically significant association between the apoptotic rate, the epithelial thickness and the thickness of the lymphocytic inflammatory infiltrate.

Gallium nitride and its alloys are direct band gap semiconductors with a wide variety of applications. Of particular importance are light emitting diodes and laser diodes. Due to the lack of suitable lattice-matched substrates, epitaxial layers contain a high density of defects such as dislocations. To reduce their number and to design a device with desired specifications, multilayered systems with varying composition (and thus material properties) are grown. Theoretical modelling is a useful tool for gaining understanding of various phenomena and materials properties. The scope of the present work is wide. It ranges from a continuum theory of dislocations treated within the linear elasticity theory, connects the continuum and atomistic level modelling for the case of the critical thickness of thin epitaxial layers, and covers some issues of simulating the electronic structure of III-nitride alloys by means of the first principle methods. The first part of this work discusses several topics involving dislocation theory. The objectives were: (i) to apply general elasticity approaches known from the literature to the specific case of wurtzite materials, (ii) to extend and summarise theoretical studies of the critical thickness in heteroepitaxy. Subsequently, (iii) to develop an improved geometrical model for threading dislocation density reduction during the growth of thick GaN films. The second part of this thesis employs first principles techniques (iv) to investigate the electronic structure of binary compounds (GaN, AlN, InN) and correlate these with experimentally available N K-edge electron energy loss near edge structure (ELNES) data, (v) to apply the special quasi-random structures method to ternary III-nitride wurtzite alloys aiming to develop a methodology for modelling wurtzite alloys and to get quantitative agreement with experimental N K-edge ELNES structures, and (vi) to theoretically study strain effects on ELNES spectra.

Hip fracture is the leading cause of acute orthopaedic hospital admission amongst the elderly, with around a third of patients not surviving one-year post-fracture. Current risk assessment tools ignore cortical bone thinning, a focal structural defect characterizing hip fragility. Cortical thickness can be measured using computed tomography, but this is expensive and involves a significant radiation dose. Dual-energy X-ray absorptiometry (DXA) is the preferred imaging modality for assessing fracture risk, and is used routinely in clinical practice. This thesis proposes two novel methods which measure the cortical thickness of the proximal femur from multi-view DXA scans. First, a data-driven algorithm is designed, implemented and evaluated. It relies on a femoral B-spline template which can be deformed to fit an individual?s scans. In a series of experiments on the trochanteric regions of 120 proximal femurs, the algorithm?s performance limits were established using twenty views in the range 0? ? 171?: estimation errors were 0.00 ? 0.50 mm. In a clinically viable protocol using four views in the range ?20? to 40?, measurement errors were ?0.05 ? 0.54 mm. The second algorithm accomplishes the same task by deforming statistical shape and thickness models, both trained using Principal Component Analysis (PCA). Three training cohorts are used to investigate (a) the estimation efficacy as a function of the diversity in the training set and (b) the possibility of improving performance by building tailored models for different populations. In a series of cross-validation experiments involving 120 femurs, minimum estimation errors were 0.00 ? 0.59 mm and ?0.01 ? 0.61 mm for the twenty- and four-view experiments respectively, when fitting the tailored models. Statistical significance tests reveal that the template algorithm is more precise than the statistical, and that both are superior to a blind estimator which naively assumes the population mean, but only in regions of thicker cortex. It is concluded that cortical thickness measured from DXA is unlikely to assist fracture prediction in the femoral neck and trochanters, but might have applicability in the sub-trochanteric region.