The processing of pure copper (Cu) has been a challenge for laser-based additive manufacturing for many years since copper powders have a high reflectivity of up to 83% of electromagnetic radiation at a wavelength of 1070 nm. In this study, Cu particles were coated with sub-micrometer tungsten (W) particles to increase the laser beam absorptivity. The coated powders were processed by powder bed fusion-laser beam for metals (PBF-LB/M) with a conventional laser system of <300 watts laser power and a wavelength of 1070 nm.
View Article and Find Full Text PDFDevelopment of welding consumables with fluorides and borides of rare earth metals is a promising area for improving the weldability of low alloy steels. As lanthanum fluoride and boride dissociate, lanthanum and boron dissolve in the weld pool and the welding arc plasma is saturated with fluorine. As a result of FeO, MnO, SiO deoxidation and FeS, MnS desulfurization, refractory lanthanum sulfides and oxides LaO, LaS are formed in the weld pool, which can be the crystallization nuclei in the weld pool and the origin of acicular ferrite nucleation.
View Article and Find Full Text PDFWeldForming; post weld treatment; recrystallization; thermomechanical simulation; numerical simulation; FEM.
View Article and Find Full Text PDFBackground: In order to evaluate the newly implemented gender-neutral HPV vaccination program, knowledge on the pre-vaccine prevalence of HPV infection is of paramount importance. Data on HPV infection among the women with no known previous cytological abnormalities are inexistent in Austria. This study presents data on the prevalence and distribution of HPV genotypes among women with no known cytological abnormalities in west Austria.
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September 2016
In-situ resistance measurements of aluminized 22MnB5 steel using a current ramp of 500 A/ms at welding force levels from 2 kN to 8 kN were conducted to obtain data on the dynamic resistance behaviour in spot welding of the material for varying mechanical and electrical loads. The data has been successfully used to calibrate a numerical transition resistance model (KMK-model, Kaars et al., 2016 [1]) in Kaars et al.
View Article and Find Full Text PDFBackground: Stage I of a preplanned 2-stage study has provided good evidence for improved glycemic control with a disease-specific enteral formula low in carbohydrates and high in monounsaturated fatty acids (MUFAs), fish oil, chromium, and antioxidants in insulin-treated type 2 diabetes. The study was continued with stage II to give confirmatory proof of these beneficial effects.
Methods: 105 patients with HbA1C>or=7.
The xylose-fermenting yeast Candida intermedia produces two isoforms of xylose reductase: one is NADPH-dependent (monospecific xylose reductase; msXR), and another is shown here to prefer NADH approximately 4-fold over NADPH (dual specific xylose reductase; dsXR). To compare the functional properties of the isozymes, a steady-state kinetic analysis for the reaction d-xylose + NAD(P)H + H(+) <--> xylitol + NAD(P)(+) was carried out and specificity constants (k(cat)/K(aldehyde)) were measured for the reduction of a series of aldehydes differing in side-chain size as well as hydrogen-bonding capabilities with the substrate binding pocket of the enzyme. dsXR binds NAD(P)(+) (K(iNAD+) = 70 microM; K(iNADP+) = 55 microM) weakly and NADH (K(i) = 8 microM) about as tightly as NADPH (K(i) = 14 microM).
View Article and Find Full Text PDFXylose reductase has been purified to apparent homogeneity from cell extracts of the fungus Cryptococcus flavus grown on D-xylose as carbon source. The enzyme, the first of its kind from the phylum Basidiomycota, is a functional dimer composed of identical subunits of 35.3 kDa mass and requires NADP(H) for activity.
View Article and Find Full Text PDFKinetic substituent effects have been used to examine the catalytic reaction profile of xylose reductase from the yeast Candida tenuis, a representative aldo/keto reductase of primary carbohydrate metabolism. Michaelis-Menten parameters (k(cat) and K(m)) for NADH-dependent enzymic aldehyde reductions have been determined using a homologous series of benzaldehyde derivatives in which substituents in meta and para positions were employed to systematically perturb the properties of the reactive carbonyl group. Kinetic isotope effects (KIEs) on k(cat) and k(cat)/K(m) for enzymic reactions with meta-substituted benzaldehydes have been obtained by using NADH (2)H-labelled in the pro-R C4-H position, and equilibrium constants for the conversion of these aldehydes into the corresponding alcohols (K(eq)) have been measured in the presence of NAD(H) and enzyme.
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