9 research outputs found

    Racial differences in systemic sclerosis disease presentation: a European Scleroderma Trials and Research group study

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    Objectives. Racial factors play a significant role in SSc. We evaluated differences in SSc presentations between white patients (WP), Asian patients (AP) and black patients (BP) and analysed the effects of geographical locations.Methods. SSc characteristics of patients from the EUSTAR cohort were cross-sectionally compared across racial groups using survival and multiple logistic regression analyses.Results. The study included 9162 WP, 341 AP and 181 BP. AP developed the first non-RP feature faster than WP but slower than BP. AP were less frequently anti-centromere (ACA; odds ratio (OR) = 0.4, P < 0.001) and more frequently anti-topoisomerase-I autoantibodies (ATA) positive (OR = 1.2, P = 0.068), while BP were less likely to be ACA and ATA positive than were WP [OR(ACA) = 0.3, P < 0.001; OR(ATA) = 0.5, P = 0.020]. AP had less often (OR = 0.7, P = 0.06) and BP more often (OR = 2.7, P < 0.001) diffuse skin involvement than had WP.AP and BP were more likely to have pulmonary hypertension [OR(AP) = 2.6, P < 0.001; OR(BP) = 2.7, P = 0.03 vs WP] and a reduced forced vital capacity [OR(AP) = 2.5, P < 0.001; OR(BP) = 2.4, P < 0.004] than were WP. AP more often had an impaired diffusing capacity of the lung than had BP and WP [OR(AP vs BP) = 1.9, P = 0.038; OR(AP vs WP) = 2.4, P < 0.001]. After RP onset, AP and BP had a higher hazard to die than had WP [hazard ratio (HR) (AP) = 1.6, P = 0.011; HR(BP) = 2.1, P < 0.001].Conclusion. Compared with WP, and mostly independent of geographical location, AP have a faster and earlier disease onset with high prevalences of ATA, pulmonary hypertension and forced vital capacity impairment and higher mortality. BP had the fastest disease onset, a high prevalence of diffuse skin involvement and nominally the highest mortality

    Assessment of fatigue life of aluminized, coarse-grained MAR247 alloy supported by full-field ESPI measurements

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    In this paper, fatigue performance of an aluminide layer coated, coarse-grained MAR247 nickel superalloy was monitored by using the full-field Electronic Speckle Pattern Interferometry (ESPI) method in the range of stress amplitude from 350MPa to 650MPa. It was found, that the ESPI method enables precise monitoring of the fatigue behaviour of coated MAR247 specimens since the area of potential failure was accurately indicated within the initial stage of fatigue damage development

    INFLUENCE OF HABITAT STRUCTURE AND CONDITIONS IN FLOODPLAIN FORESTS ON MOLLUSC ASSEMBLAGES

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    Alder floodplain forests are a rare and threatened forest type in Europe. These forests can be very rich in mollusc species. The intermediate disturbance hypothesis predicts that species richness should peak at intermediate inundation frequency, that is, at intermediate elevation above the river level. We additionally hypothesized that constantly high soil moisture can distort the usually positive correlation between the amounts of downed deadwood and snail richness, and that tree stems might be more favourable than deadwood because their vertical structure provides a better refuge during inundation events. To this end, we sampled molluscs from a core area of 20 x 20 m from eight alluvial forests with black alder in the surroundings of Lodz, Central Poland. In each core area, substrate was collected from eight random plots (0.25 m(2) each). We also recorded soil pH, vascular plant species and mosses diversity, along with other structural variables. Plant indicator values were calculated according to Ellenberg. Soil quality (amongst others: soil pH, reactivity value, nutrient and moisture availability) decreased with increasing elevation above the river level. In the plot samples, we found a total of 18,497 individuals from 52 species. Mollusc species richness dropped stronger than densities with an increasing elevation above the river level Main influences on mollusc richness and abundance originated from positive correlations with soil pH and moisture. An additional hand sampling campaign on tree stems and deadwood items in the core area revealed that coarse woody debris items on average carried twice as many individuals as did tree stems. Deadwood and tree stems supported similar numbers of snail species per item, but beta-diversity was higher on deadwood. Consequently, Jackknife 2 predicted that deadwood is utilized by about 46 species, whereas tree stems only support about 39 species. Our results indicate (1) that mollusc richness peaks at low elevations above normal water level in this type of forest, (2) that intact hydrological regimes are associated with high soil quality and mollusc biodiversity, and (3) suggest that coarse woody debris adds resources, refuges and a dispersal agent for the alder forest floor fauna

    Nondestructive Methodology for Identification of Local Discontinuities in Aluminide Layer-Coated MAR 247 during Its Fatigue Performance

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    In this paper, the fatigue performance of the aluminide layer-coated and as-received MAR 247 nickel superalloy with three different initial microstructures (fine grain, coarse grain and column-structured grain) was monitored using nondestructive, eddy current methods. The aluminide layers of 20 and 40 µm were obtained through the chemical vapor deposition (CVD) process in the hydrogen protective atmosphere for 8 and 12 h at the temperature of 1040 °C and internal pressure of 150 mbar. A microstructure of MAR 247 nickel superalloy and the coating were characterized using light optical microscopy (LOM), scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). It was found that fatigue performance was mainly driven by the initial microstructure of MAR 247 nickel superalloy and the thickness of the aluminide layer. Furthermore, the elaborated methodology allowed in situ eddy current measurements that enabled us to localize the area with potential crack initiation and its propagation during 60,000 loading cycles

    A Novel Method for High Temperature Fatigue Testing of Nickel Superalloy Turbine Blades with Additional NDT Diagnostics

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    In this paper, a novel method for high temperature fatigue strength assessment of nickel superalloy turbine blades after operation at different times (303 and 473 h) was presented. The studies included destructive testing (fatigue testing at temperature 950 °C under cyclic bending load), non-destructive testing (Fluorescent Penetrant Inspection and Eddy Current method), and finite element modelling. High temperature fatigue tests were performed within load range from 5200 to 6600 N using a special self-designed blade grip attached to the conventional testing machine. The experimental results were compared with the finite element model generated from the ANSYS software. It was found that failure of turbine blades occurred in the area with the highest stress concertation, which was accurately predicted by the finite element (FE) model

    Aluminide Thermal Barrier Coating for High Temperature Performance of MAR 247 Nickel Based Superalloy

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    In this paper, mechanical properties of the as-received and aluminide layer coated MAR 247 nickel based superalloy were examined through creep and fatigue tests. The aluminide layer of 20 µm was obtained through the chemical vapor deposition (CVD) process in the hydrogen protective atmosphere for 8 h at the temperature of 1040 °C and internal pressure of 150 mbar. A microstructure of the layer was characterized using the scanning electron microscopy (SEM) and X-ray Energy Dispersive Spectroscopy (EDS). It was found that aluminide coating improve the high temperature fatigue performance of MAR247 nickel based superalloy at 900 °C significantly. The coated MAR 247 nickel based superalloy was characterized by the stress amplitude response ranging from 350 MPa to 520 MPa, which is twice as large as that for the uncoated alloy
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