2,634 research outputs found

    The regulation of urease synthesis by repression in N. crassa

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    Regulation of urease synthesis by repressio

    Summertime elemental mercury exchange of temperate grasslands on an ecosystem-scale

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    In order to estimate the air-surface mercury exchange of grasslands in temperate climate regions, fluxes of gaseous elemental mercury (GEM) were measured at two sites in Switzerland and one in Austria during summer 2006. Two classic micrometeorological methods (aerodynamic and modified Bowen ratio) have been applied to estimate net GEM exchange rates and to determine the response of the GEM flux to changes in environmental conditions (e. g. heavy rain, summer ozone) on an ecosystem-scale. Both methods proved to be appropriate to estimate fluxes on time scales of a few hours and longer. Average dry deposition rates up to 4.3 ng m(-2) h(-1) and mean deposition velocities up to 0.10 cm s(-1) were measured, which indicates that during the active vegetation period temperate grasslands are a small net sink for atmospheric mercury. With increasing ozone concentrations depletion of GEM was observed, but could not be quantified from the flux signal. Night-time deposition fluxes of GEM were measured and seem to be the result of mercury co-deposition with condensing water. Effects of grass cuts could also be observed, but were of minor magnitude

    Observed crustal uplift near the Southern Patagonian Icefield constrains improved viscoelastic Earth model

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    Thirty‒one GPS geodetic measurements of crustal uplift in southernmost South America determined extraordinarily high trend rates (> 35 mm/yr) in the north‒central part of the Southern Patagonian Icefield. These trends have a coherent pattern, motivating a refined viscoelastic glacial isostatic adjustment model to explain the observations. Two end‒member models provide good fits: both require a lithospheric thickness of 36.5 ± 5.3 km. However, one end‒member has a mantle viscosity near η =1.6 ×1018 Pa s and an ice collapse rate from the Little Ice Age (LIA) maximum comparable to a lowest recent estimate of 1995–2012 ice loss at about −11 Gt/yr. In contrast, the other end‒member has much larger viscosity: η = 8.0 ×1018 Pa s, half the post–LIA collapse rate, and a steadily rising loss rate in the twentieth century after AD 1943, reaching −25.9 Gt/yr during 1995–2012.Fil: Lange, H.. Technische Universitaet Dresden; AlemaniaFil: Casassa, G.. Centro de Estudios Cientificos; Chile. Universidad de Magallanes; ChileFil: Ivins, E. R.. Institute of Technology. Jet propulsion Laboratory; Estados UnidosFil: Schroeder, L.. Technische Universitaet Dresden; AlemaniaFil: Fritsche, M.. Technische Universitaet Dresden; AlemaniaFil: Richter, Andreas Jorg. Technische Universitaet Dresden; Alemania. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas. Departamento de Astrometría; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Groh, A.. Technische Universitaet Dresden; AlemaniaFil: Dietrich, R.. Technische Universitaet Dresden; Alemani

    Parameterized optimized effective potential for the ground state of the atoms He through Xe

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    Parameterized orbitals expressed in Slater-type basis obtained within the optimized effective potential framework as well as the parameterization of the potential are reported for the ground state of the atoms He through Xe. The total, kinetic, exchange and single particle energies are given for each atom.Comment: 47 pages, 1 figur

    Alternative antibody for the detection of CA125 antigen: a European multicenter study for the evaluation of the analytical and clinical performance of the Access (R) OV Monitor assay on the UniCel (R) Dxl 800 Immunoassay System

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    Background: Cancer antigen CA125 is known as a valuable marker for the management of ovarian cancer. Methods: The analytical and clinical performance of the Access OV Monitor Immunoassay System (Beckman Coulter) was evaluated at five different European sites and compared with a reference system, defined as CA125 on the Elecsys System (Roche Diagnostics). Results: Total imprecision (%CV) of the OV Monitor ranged between 3.1% and 8.8%, and inter-laboratory reproducibility between 4.7% and 5.0%. Linearity upon dilution showed a mean recovery of 100% (SD+8.1%). Endogenous interferents had no influence on OV Monitor levels (mean recoveries: hemoglobin 107%, bilirubin 103%, triglycericles 103%). There was no high-dose hook effect up to 27,193 kU/L. Clinical performance investigated in sera from 1811 individuals showed a good correlation between the Access OV Monitor and Elecsys CA125 (R = 0.982, slope = 0.921, intercept = + 1.951). OV Monitor serum levels were low in healthy individuals (n = 267, median = 9.7 kU/L, 95th percentile = 30.8 kU/L), higher in individuals with various benign diseases (n = 549, medians = 10.9-16.4 kU/L, 95th percentiles = 44.2-355 kU/L) and even higher in individuals suffering from various cancers (n = 995, medians= 12.4-445 kU/L; 95th percentiles = 53.4-4664 kU/L). Optimal diagnostic accuracy for cancer detection against the relevant benign control group by the OV Monitor was found for ovarian cancer {[}area under the curve (AUC) 0.898]. Results for the reference CA125 assay were comparable (AUC 0.899). Conclusions: The Access OV Monitor provides very good methodological characteristics and demonstrates an excellent analytical and clinical correlation with Elecsys CA125. The best diagnostic accuracy for the OV Monitor was found in ovarian cancer. Our results also suggest a clinical value of the OV Monitor in other cancers

    Modified protocol of harvesting, extraction, and normalization approaches for gas chromatography mass spectrometry-based metabolomics analysis of adherent cells grown under high fetal calf serum conditions

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    A gas chromatography mass spectrometry (GC-MS) metabolomics protocol was modified for quenching, harvesting, and extraction of metabolites from adherent cells grown under high (20%) fetal calf serum conditions. The reproducibility of using either 50% or 80% methanol for quenching of cells was compared for sample harvest. To investigate the efficiency and reproducibility of intracellular metabolite extraction, different volumes and ratios of chloroform were tested. Additionally, we compared the use of total protein amount versus cell mass as normalization parameters. We demonstrate that the method involving 50% methanol as quenching buffer followed by an extraction step using an equal ratio of methanol:chloroform:water (1:1:1, v/v/v) followed by the collection of 6 mL polar phase for GC-MS measurement was superior to the other methods tested. Especially for large sample sets, its comparative ease of measurement leads us to recommend normalization to protein amount for the investigation of intracellular metabolites of adherent human cells grown under high (or standard) fetal calf serum conditions. To avoid bias, care should be taken beforehand to ensure that the ratio of total protein to cell number are consistent among the groups tested. For this reason, it may not be suitable where culture conditions or cell types have very different protein outputs (e.g., hypoxia vs. normoxia). The full modified protocol is available in the Supplementary Materials

    Walnut Allergy Across Europe: Distribution of Allergen Sensitization Patterns and Prediction of Severity

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    Background: Walnut allergy is common across the globe, but data on the involvement of individual walnut components are scarce. Objectives: To identify geographical differences in walnut component sensitization across Europe, explore cosensitization and cross-reactivity, and assess associations of clinical and serological determinants with severity of walnut allergy. Methods: As part of the EuroPrevall outpatient surveys in 12 European cities, standardized clinical evaluation was conducted in 531 individuals reporting symptoms to walnut, with sensitization to all known walnut components assessed in 202 subjects. Multivariable Lasso regression was applied to investigate predictors for walnut allergy severity. Results: Birch-pollen-related walnut sensitization (Jug r 5) dominated in Northern and Central Europe and lipid transfer protein sensitization (Jug r 3) in Southern Europe. Profilin sensitization (Jug r 7) was prominent throughout Europe. Sensitization to storage proteins (Jug r 1, 2, 4, and 6) was detected in up to 10% of subjects. The walnut components that showed strong correlations with pollen and other foods differed between centers. The combination of determinants best predicting walnut allergy severity were symptoms upon skin contact with walnut, atopic dermatitis (ever), family history of atopic disease, mugwort pollen allergy, sensitization to cat or dog, positive skin prick test result to walnut, and IgE to Jug r 1, 5, 7, or carbohydrate determinants (area under the curve = 0.81; 95% CI, 0.73-0.89). Conclusions: Walnut-allergic subjects across Europe show clear geographical differences in walnut component sensitization and cosensitization patterns. A predictive model combining results from component-based serology testing with results from extract-based testing and information on clinical background allows for good discrimination between mild to moderate and severe walnut allerg
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