915 research outputs found

    Methods of determining loads and fiber orientations in anisotropic non-crystalline materials using energy flux deviation

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    An ultrasonic wave is applied to an anisotropic sample material in an initial direction and an angle of flux deviation of the ultrasonic wave front is measured from this initial direction. This flux deviation angle is induced by the unknown applied load. The flux shift is determined between this flux deviation angle and a previously determined angle of flux deviation of an ultrasonic wave applied to a similar anisotropic reference material under an initial known load condition. This determined flux shift is then compared to a plurality of flux shifts of a similarly tested, similar anisotropic reference material under a plurality of respective, known load conditions, whereby the load applied to the particular anisotropic sample material is determined. A related method is disclosed for determining the fiber orientation from known loads and a determined flux shift

    Method of determining load in anisotropic non-crystalline materials using energy flux deviation

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    An ultrasonic wave is applied to an anisotropic sample material in an initial direction and the intensity of the ultrasonic wave is measured on an opposite surface of the sample material by two adjacent receiving points located in an array of receiving points. A ratio is determined between the measured intensities of two adjacent receiving points, the ratio being indicative of an angle of flux deviation from the initial direction caused by an unknown applied load. This determined ratio is then compared to a plurality of ratios of a similarly tested, similar anisotropic reference material under a plurality of respective, known load conditions, whereby the load applied to the particular anisotropic sample material is determined. A related method is disclosed for determining the fiber orientation from known loads and a determined flux shift

    Afferent arteriolopathy and glomerular collapse but not segmental sclerosis induce tubular atrophy in old spontaneously hypertensive rats

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    In chronic renal disease, the temporal and spatial relationship between vascular, glomerular and tubular changes is still unclear. Hypertension, an important cause of chronic renal failure, leads to afferent arteriolopathy, segmental glomerulosclerosis and tubular atrophy in the juxtamedullary cortex. We investigated the pathological changes of hypertensive renal disease in aged spontaneously hypertensive rats using a large number of serial sections, where we traced and analyzed afferent arteriole, glomerulus and proximal tubule of single nephrons. Our major finding was that both afferent arteriolopathy and glomerular capillary collapse were linked to tubular atrophy. Only nephrons with glomerular collapse (n = 13) showed tubules with reduced diameter indicating atrophy [21.66 ± 2.56 μm vs. tubules in normotensive Wistar Kyoto rats (WKY) 38.56 ± 0.56 μm, p < 0.05], as well as afferent arteriolar wall hypertrophy (diameter 32.74 ± 4.72 μm vs. afferent arterioles in WKY 19.24 ± 0.98 μm, p < 0.05). Nephrons with segmental sclerosis (n = 10) did not show tubular atrophy and tubular diameters were unchanged (35.60 ± 1.43 μm). Afferent arteriolar diameter negatively correlated with glomerular capillary volume fraction (r = −0.36) and proximal tubular diameter (r = −0.46) implying reduced glomerular and tubular flow. In line with this, chronically damaged tubules showed reduced staining for the ciliary protein inversin indicating changed ciliary signalling due to reduced urinary flow. This is the first morphological study on hypertensive renal disease making correlations between vascular, glomerular and tubular components of individual nephron units. Our data suggest that afferent arteriolopathy leads to glomerular collapse and reduced urinary flow with subsequent tubular atrophy

    Disparities in the completion of steps to kidney transplantation: protocol for a systematic review

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    Introduction Disparities in access to transplantation have been well documented. The extant literature, however, focuses largely on disparities and related barriers for African-American patients and none has used the steps to transplantation as a guiding framework. This review will catalogue disparities in the steps to transplantation as well as the barriers and facilitators to completion of each step identified in the extant literature. The results of the review will be used to generate recommendations for future research to improve equity in access to kidney transplantation. Methods and analysis Standard procedures will be used in the conduct of the review. Searches will be performed using the following electronic databases: PubMed/Medline, PsycINFO, CINHAL, EMBASE, Cochrane library and Web of Science. Reports of original research will be eligible for inclusion if they are published from 2005 to present, written or available in English language, performed in the USA, enrol adult participants (18 years of age or more), and employ descriptive or observational designs. Two authors will independently screen retrieved articles for inclusion. MaxQDA will be used for data analysis and management. All included reports will be coded for article characteristics; disparities identified; barriers and motivators of completion of steps to transplantation; and proposed solutions to disparities and barriers. Each report will be coded independently by two authors and discrepancies resolved by discussion among the full team. A qualitative approach to data analysis is planned. Risk of bias will be assessed using standard procedures. Ethics and dissemination The findings will provide crucial information on the current status of disparities in access to transplantation. PRISMA guidelines will be followed in reporting the results of the review. It is anticipated that these results will inform research which seeks to increase parity in access to transplantation. Systematic review registration PROSPERO CRD42014015027

    Finite Element Model of Stress Wave Topology in Unidirectional Graphite/Epoxy: Wave Velocities and Flux Deviations

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    Until recently, the use of a finite element model (FEM) to simulate stress wave propagation has been limited to solutions where the number of degrees of freedom are kept to a minimum, because of hardware limitations on computer memory and computational speed. With the advent of a numte

    Exploring the mediating role of relationship quality in online services

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    This paper is the first to examine the mediating role of relationship quality in the online context. By investigating this major tenet of customer relationship management theory in this nascent service setting, this paper clarifies the interaction between service quality and relationship quality, as they impact on customer loyalty. The findings reveal some fundamental differences in the way that strong relationships and loyalty develop in the online setting vis-à-vis the offline setting. The findings of this empirical research support the existence of a partial mediating relationship. While effective service delivery was found to enhance the quality of customer-firm relationships, and consequently, the customer’s perceived loyalty to their main financial institution; there was also evidence of a concurrent link between service quality and loyalty. This finding suggests that a strong relationship does not make customers immune to poor future services, and that firms operating in the online environment should maintain high service standards if they are to enjoy continued loyalty from their customers

    Age-related glomerulosclerosis and interstitial fibrosis in Milan normotensive rats: A podocyte disease

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    Age-related glomerulosclerosis and interstitial fibrosis in Milan normotensive rats: A podocyte disease. In Milan normotensive (MNS) rats glomerulosclerosis and interstitial fibrosis develop spontaneously in the absence of hypertension. Renal changes were sequentially assessed in these rats between 2 and 10 months of age. At 10 months, rats were characterized by heavy proteinuria, increased serum creatinine, focal or global glomerulosclerosis in 51 ± 12% of the glomeruli as well as tubulointerstitial injury involving > 25% of the section area. Cell injury in podocytes (evidenced as increased expression of desmin and by electron microscopy) and interstitial fibroblasts (increased expression of α-smooth muscle actin) and mild glomerular hypertrophy were witnessed as early as three to four months of age and preceded glomerulosclerosis and interstitial fibrosis. Only minor evidence of mesangial cell activation (as assessed by glomerular de novo α-smooth muscle actin or type I collagen expression or increased cell proliferation) was noted throughout the observation period. Later stages of the disease were characterized by glomerular and/or tubulointerstitial macrophage influx and osteopontin expression (a chemoattractant), mild accumulation of lymphocytes, platelets, fibrinogen, as well as by a progressive accumulation of various matrix proteins. Progressive renal disease in MNS rats is thus noteworthy for the relative lack of mesangial cell activation. Rather, early podocyte damage, induced by yet unknown mechanisms, may underlie the development of glomerulosclerosis and subsequent interstitial fibrosis

    Putting theory oriented evaluation into practice

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    Evaluations of gaming simulations and business games as teaching devices are typically end-state driven. This emphasis fails to detect how the simulation being evaluated does or does not bring about its desired consequences. This paper advances the use of a logic model approach which possesses a holistic perspective that aims at including all elements associated with the situation created by a game. The use of the logic model approach is illustrated as applied to Simgame, a board game created for secondary school level business education in six European Union countries
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