901 resultados para strain and stress distribution


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End-stage liver disease associated with hepatitis C virus (HCV) infection is now the leading indication for liver transplantation in adults. However, reinfection of the graft is universal. We aimed to determine predictors of outcome of HCV-Iiver transplant recipients in the Australian and New Zealand communities. The following variables were analysed: demographic factors, coexistent pathology at the time of transplantation, HCV genotype, and donor age. Outcomes measures were: 1. mortality; 2. development of HCV-related complications, which were stage 3 or 4 fibrosis, or mortality from HCV-related graft failure, or both. Between January 1989 and December 30, 1999, 182 patients were transplanted for HCV-associated cirrhosis. The median follow-up period was 4 years (range, 0 to 13 years). Genotype data were available on 157 patients. The distribution of genotypes among the 157 patients was as follows: 36 (23%) genotype la, 30 (19%) genotype 1b, 4 (9%) genotype 1, 17 (11%) genotype 2, 41 (26%) genotype 3a, and 16 (10%) genotype 4. Eight (5%) patients were HCV-polymerase chain reaction (PCR)-negative (but HCV-antibody positive). Donor age and genotype 4 were associated with an increased risk of retransplantation or death (P < .001 and.05, respectively). Meanwhile, donor age, genotype 4, and pretransplant excess alcohol were risk factors for the development of HCV-related complications (P = .004, .008, and .02, respectively). In contrast, patients with genotype 3a were less likely to develop HCV-related complications (P = .05). In a population of HCV liver transplant recipients with a heterogeneous genotype distribution, donor age, and genotype 4, were predictors of a worse outcome, whereas genotype 3 was associated with a more favorable outcome.

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Pumicestone Passage is a narrow waterway that lies to the north of and adjacent to Moreton Bay, and between mainland Queensland and Bribie Island, Australia. Anecdotal reports have suggested that the Passage is home to dugongs year-round despite winter water temperatures that are known to cause dugongs to migrate elsewhere. To examine the pattern of distribution and abundance of dugongs within the passage on a year-round basis, eight years of sightings data collected by a charter boat operator were examined. Dedicated aerial surveys of the passage were also conducted at two-monthly intervals over two years, and more intensively over a single winter. Dugong sightings were examined in relation to water temperatures and seagrass prevalence. The number of dugongs sighted in the area on any one survey varied from 0 to 13. Dugongs were seen in all months of the year and in each of the eight winters, indicating that Pumicestone Passage is used year-round despite winter water temperatures dropping to below 18 degrees C from June to August inclusive and below 16 degrees C in June. All dugong sightings occurred in the southern part of the passage, south of Tripcony Bight. Dugongs were associated with shallows that support Halophila and Halodule species of seagrass, food species that are favoured elsewhere in their range. The northern part of the passage also supports seagrasses that are eaten by dugongs and has water temperature ranges that are not appreciably different to those of the southern passage. However, the narrow channels and very shallow nature of the northern passage provides little to no deep-water refugia for dugongs and the seagrass beds are less extensive. This study suggests that southern Pumicestone Passage requires protection concomitant with it being a year-round refuge of the vulnerable dugong.

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The interferon (IFN) response is the first line of defense against viral infections, and the majority of viruses have developed different strategies to counteract IFN responses in order to ensure their survival in an infected host. In this study, the abilities to inhibit IFN signaling of two closely related West Nile viruses, the New York 99 strain (NY99) and Kunjin virus (KUN), strain MRM61C, were analyzed using reporter plasmid assays, as well as immunofluorescence and Western blot analyses. We have demonstrated that infections with both NY99 and KUN, as well as transient or stable transfections with their replicon RNAs, inhibited the signaling of both alpha/beta IFN (IFN-alpha/beta) and gamma IFN (IFN-gamma) by blocking the phosphorylation of STAT1 and its translocation to the nucleus. In addition, the phosphorylation of STAT2 and its translocation to the nucleus were also blocked by KUN, NY99, and their replicons in response to treatment with IFN-alpha. IFN-alpha signaling and STAT2 translocation to the nucleus was inhibited when the KUN nonstructural proteins NS2A, NS2B, NS3, NS4A, and NS4B, but not NS1 and NS5, were expressed individually from the pcDNA3 vector. The results clearly demonstrate that both NY99 and KUN inhibit IFN signaling by preventing STAT1 and STAT2 phosphorylation and identify nonstructural proteins. responsible for this inhibition.

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Pesticides in soil are subject to a number of processes that result in transformation and biodegradation, sorption to and desorption from soil components, and diffusion and leaching. Pesticides leaching through a soil profile will be exposed to changing environmental conditions as different horizons with distinct physical, chemical and biological properties are encountered. The many ways in which soil properties influence pesticide retention and degradation need to be addressed to allow accurate predictions of environmental fate and the potential for groundwater pollution. Degradation and sorption processes were investigated in a long-term (100 days) study of the chloroacetanilide herbicide, acetochlor. Soil cores were collected from a clay soil profile and samples taken from 0-30cm (surface), 1.0-1.3m (mid) and 2.7-3.0m (deep) and treated with acetochlor (2.5, 1.25, 0.67 mu g acetochlor g(-1) dry wt soil, respectively). In sterile and non-sterile conditions, acetochlor concentration in the aqueous phase declined rapidly from the surface and subsoil layers, predominantly through nonextractable residue (NER) formation on soil surfaces, but also through biodegradation and biotic transformation. Abiotic transformation was also evident in the sterile soils. Several metabolites were produced, including acetochlor-ethane sulphonic acid and acetochlor-oxanilic acid. Transformation was principally microbial in origin, as shown by the differences between non-sterile and sterile soils. NER formation increased rapidly over the first 21 days in all soils and was mainly associated with the macroaggregate (> 2000 mu m diameter) size fractions. It is likely that acetochlor is incorporated into the macroaggregates through oxidative coupling, as humification of particulate organic matter progresses. The dissipation (ie total loss of acetochlor) half-life values were 9.3 (surface), 12.3 (mid) and 12.6 days (deep) in the non-sterile soils, compared with 20.9 [surface], 23.5 [mid], and 24 days [deep] in the sterile soils, demonstrating the importance of microbially driven processes in the rapid dissipation of acetochlor in soil.

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The distribution of anaerobic ammonium oxidation (anammox) in nature has been addressed by only a few environmental studies, and our understanding of how anammox bacteria compete for substrates in natural environments is therefore limited. In this study, we measure the potential anammox rates in sediment from four locations in a subtropical tidal river system. Porewater profiles of NOx- (NO2- plus NO3-) and NO2- were measured with microscale biosensors, and the availability of NO2- was compared with the potential for anammox activity. The potential rate of anammox increased with increasing distance from the mouth of the river and correlated strongly with the production of nitrite in the sediment and with the average concentration or total pool of nitrite in the suboxic sediment layer. Nitrite accumulated both from nitrification and from NOx- reduction, though NOx- reduction was shown to have the greatest impact on the availability of nitrite in the suboxic sediment layer. This finding suggests that denitrification, though using NO2- as a substrate, also provides a substrate for the anammox process, which has been suggested in previous studies where microscale NO2- profiles were not measured.

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Rumors collected from a large public hospital undergoing change were content analyzed, and a typology comprising the following five broad types of change-related rumors was developed: rumors about changes to job and working conditions, nature of organizational change, poor change management, consequences of the change for organizational performance, and gossip-rumors. Rumors were also classified as positive or negative on the basis of their content. As predicted, negative rumors were more prevalent than positive rumors. Finally, employees reporting negative rumors also reported more change-related stress as compared to those who reported positive rumors and those who did not report any rumors. The authors propose that rumors be treated as verbal symbols and expressions of employee concerns during organizational change.

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A modified straight leg raising (SLR) in which ankle dorsiflexion is performed before hip flexion has been suggested to diagnose distal neuropathies such as tarsal tunnel syndrome. This study evaluates the clinical hypothesis that strain in the nerves around the ankle and foot caused by ankle dorsiflexion can be further increased with hip flexion. Linear displacement transducers were inserted into the sciatic, tibial, and plantar nerves and plantar fascia of eight embalmed cadavers to measure strain during the modified SLR. Nerve excursion was measured with a digital calliper. Ankle dorsiflexion resulted in a significant strain and distal. excursion of the tibial nerve. With the ankle in dorsiflexion, the proximal excursion and tension increase in the sciatic nerve associated with hip flexion were transmitted distally along the nerve from the hip to beyond the ankle. As hip flexion had an impact on the nerves around the ankle and foot but not on the plantar fascia, the modified SLR may be a useful test to differentially diagnose plantar heel pain. Although the modified SLR caused the greatest increase in nerve strain nearest the moving joint, mechanical forces acting on peripheral nerves are transmitted well beyond the moving joint. (c) 2006 Orthopaedic Research Society.

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Iron (Fe) bioavailability in unpolished, polished grain and bran fraction of five rice genotypes with a range of Fe contents was measured by in vitro digestion and cultured Caco-2 cells of cooked grain. There was a significant difference in Fe bioavailability among the five rice genotypes tested, in both the unpolished and polished grain. The range of Fe bioavailability variation in polished rice was much wider than that of unpolished, suggesting the importance of using Fe levels and bioavailability in polished rice grain as the basis for selecting high-Fe rice cultivars for both agronomic and breeding purposes. Milling and polishing the grain to produce polished (or white) rice increased Fe bioavailability in all genotypes. Iron bioavailability in polished rice was high in the UBON2 and Nishiki, intermediate in both IR68144 and KDML105, and low in CMU122. All genotypes had low bioavailability of Fe in bran fraction compared to unpolished and polished grain, except in CMU122. CMU122 contained the lowest level of bioavailable Fe in unpolished and polished grain and bran, because of the dark purple pericarp colored grain and associated tannin content. The level of bioavailable Fe was not significantly correlated with grain Fe concentration or grain phytate levels among these five genotypes tested. The negative relationship between Fe bioavailability and the levels of total extractable phenol was only observed in unpolished (r = -0.83**) and bran fraction (r = -0.50*). The present results suggested that total extractable phenol and tannin contents could also contribute to lowering bioavailability of Fe in rice grain, in addition to phytate. (c) 2006 Society of Chemical Industry