The effect of germination process on the superoxide dismutase-like activity and thiamine,riboflavin and mineral contents of rapeseeds

Seeds of double low oilseed rape variety Mango (Brassica napus, var. oleifera) were subjected to a 7-day germination at 25 °C and 95% moisture content in darkness in a conditioning cabinet. The effects of the germination process on the superoxide dismutase-like activity (SOD-like activity), thiamine (vitamin B₁) and riboflavin (vitamin B₂) and minerals, such as Ca, Mg, Cu, Fe and Mn, were studied. Correlations between individual mineral contents, vitamin B₁ and B₂ contents, and the ability of phosphate buffered saline (PBS) extracts from germinated rapeseed to scavenge superoxide anion radicals in vitro were also investigated. SOD-like activity showed a gradual increase after the second day of germination, reaching a maximum level on the sixth day, and remained almost constant up to the end of the germination period. During germination, thiamine underwent a progressive decrease up to the sixth day, reaching a constant level between the sixth and the seventh day. In contrast, riboflavin content increased throughout the germination period up to the fifth day, and after that a constant level was observed. Levels of Ca and Mg were almost constant up to the fourth day and after that an increase of these minerals was observed. Cu and Mn increased during the germination process, and retentions of 33% and 22%, respectively, were observed at the end of germination. Fe content dropped after 1 day of germination and from there onward it started to increase gradually and an 18% retention was observed in 7-day germinated seeds. Positive correlations between SOD-like activity and riboflavin (r = 0.87), Cu (r = 0.74) and Mn (r = 0.87) were found during rapeseed germination.     

Validation of the thermomechanical microstructural model for closed-die forging

The objective of the paper is the assessment of the predictive ability of the thermomechanical-microstructural model for the closed-die forging process. The model combines the rigid-plastic flow formulation with the finite element solution of the Fourier equation with the closed-form equations describing processes of recrystallization and grain growth. Experimental validation of the mechanical and thermal components of the model is presented in earlier publications; present work focuses on the microstructural part. Experiment includes closed-die forging of the carbon-manganese steel samples and the measurements of the grain size on the cross-sections of the forgings after the deformation. Spherical samples, which involve significant inhomogeneity of the strain and the temperature fields, have been chosen for a presentation of the results.     

Microstructure and mechanical properties of nanostructure multilayer CrN/Cr coatings on titanium alloy

Five different nanostructured, multilayer coatings (CrN/Cr)x8 with different thickness ratio of Cr and CrN layers were deposited by PAPVD (Plasma Assisted Physical Vapour Deposition) vacuum arc method on Ti6Al4V titanium alloy. The microstructure, chemical and phase composition of the CrN and Cr sub-layers were characterized by SEM with EDX and Cs-corrected dedicated STEM on cross-sections prepared by focus ion beam. Besides, hardness and Young's modulus of the (Cr/CrN)x8 coatings has been measured. The adhesion has been tested by scratch test method. The obtained (CrN/Cr) multilayer coatings, 5-6 μm in thickness, have homogeneous and nanocrystalline structure, free of pores and cracks. The microstructures of Cr and CrN layers consist of columnar grains below 100 nm in diameter. The hardness and Young's modulus of these coatings depend linearly on thickness ratio of Cr and CrN layers. The decrease of the thickness ratio Cr/CrN 0.81 to 0.15 results in the increase of hardness from 1275 HV to 1710 HV and Young's modulus from 260 GPa to 271 GPa.     

Picoliter rheology of gaseous media using a rotating optically trapped birefringent microparticle

An optically trapped birefringent microparticle is rotated by a circularly polarized beam in a confined gaseous medium. By recording the terminal rotation velocity and the change in polarization of the incident trapping beam, we determine the viscosity by probing a picoliter volume of air, carbon dioxide, and argon in the vicinity of the microparticle. We also characterize the optical force acting on a trapped particle in air using the generalized Lorenz-Mie theory taking into account the aberrations present. This opens up a new potential application of optical tweezers for the accurate measurement of gas viscosity in confined geometries.     

Rapeseed protein polyanion interactions —Turbidimetric studies in systems with phosphate-containing polyanions: phytic acid and octametaphosphate

The interaction of two main protein fractions of rapeseed —the 12 S globulin and the low-molecular albumin fraction —with two phosphate-containing polyanions —phytic acid and octametaphosphate (OMP) —has been studied using turbidimetric titration and chemical analysis after precipitation. Both proteins form insoluble complexes with the polyanions below the isoelectric point. The globulin is precipitated quantitatively by both polyanions at pH 3.0. A precipitation of more than 90% of the albumin occurs by OMP, while phytic acid precipitates only 80% of this protein at pH 3.0. Increasing amounts of polyanions over the precipitation points result in a partial solubilization of albumin-polyanion complexes. The amount of polyanions bound to the proteins increases with decreasing pH. A (1:1)-stoichiometry of phytic acid binding on the globulin has been found at pH 3.0, while the ratio of phosphate groups of OMP to basic groups of globulin is only 8.0. The maximum binding of both anions at the precipitation point amounts to 0.8 mol phosphate per mol basic groups of albumin with both polyanions at pH 3.0 using turbidimetry. An excess binding of polyanions to the globulin has been found with phytic acid at pH < 3.0 and with OMP at pH 3.0 after increasing the amount of OMP over the precipitation point.     

Microstructure, fatigue and corrosion properties of the Ti-Al intermetallic layers

In this research the microstructure and mechanical properties of Ti-Al intermetallic layers before and after exposure to corrosive environments have been evaluated. The intermetallic layers have been deposited on the Ti6Al2Cr2Mo titanium alloy by the duplex method. For this purpose, a coating of magnetron sputtered Al was deposited on titanium specimens. Subsequently, these sputtered titanium alloy substrates were treated under glow discharge conditions. The uncoated and coated samples were exposed to cyclic acidified synthetic sea water and an environment composed of 100% hydrogen sulphide. Exposure in those aggressive environments did not have an effect on the high surface microhardness of the Ti-Al layers. Furthermore, the surface treatment significantly increased the fatigue properties of the titanium alloy.     

Microstructure and mechanical properties of a Pt-Rh alloy produced by powder metallurgy and subjected to plastic working

The paper presents the results of investigations of the Pt-Rh8 wires produced by powder metallurgy. The powder was consolidated by isostatic pressing followed by sintering. Examinations of the microstructure and the microhardness of the wires thus obtained showed that this treatment yields solid wires characterized by fine-grained microstructure and low porosity. The wires have better mechanical properties than those produced by plastic treatment of moulded alloys.     

Silver uptake byAgaricus bisporus from an artificially enriched substrate

The champignon mushroomAgaricus bisporus was cultivated on compost (wheat and rye straw, hens' manure, gypsum, urea and peat) artificially fortified with silver nitrate added at four different concentrations (0.01, 0.1, 1.0 and 10.3 mg/kg) and 0 mg/kg (control) on a dry weight basis. The method of measurement was flame atomic absorption spectrophotometry after dry ashing of the samples at 420° C and dissolving the residue in 1M nitric acid. The highest concentration of silver, reaching between 120±30–150±36 mg/kg on a dry weight basis, was observed in fruit bodies grown on the most contaminated substrate containing 10.3 mg added Ag/kg dry weight. The silver concentration in caps/stalks/whole fruit bodies ofA. bisporus was positively correlated (r=0.72; P<0.001) with an increasing level of fortification of the substrate. The bioconcentration factor (BCF) of silver in caps/stalks/whole fruit bodies ofA. bisporus was inversely correlated (–0.44bisporus.

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Silberaufnahme von Champignons (Agaricus bisporus) aus künstlich angereichertem Substrat

Zusammenfassung Champignons (Agaricus bisporus) wurden auf Kompost (Weizen- und Roggenstroh, Hühnerdung, Gips, Harnstoff und Torf) gezüchtet, welcher künstlich mit Silbernitrat in vier verschiedenen Mengen-0 (Kontrolle), 0,01, 0,1, 1,0 und 10,3 mg/kg-Trockenmasse angereichert wurde. Als Meßmethode wurde die Flammen AAS verwendet nach dem trockenen Veraschen der Proben bei 420 °C und Auflösen des Rückstandes in 1 M Salpetersäure.Die größte Silberkonzentration von 12±4–14±3 mg/kg Feuchtmasse und 120±30–150±36 mg/kg Trockenmasse wurde in den Fruchtkörpern festgestellt, die auf einem 10,3 mg Ag/kg Trockenmasse enthaltendem Substrat gewachsen sind. Die Silberkonzentration in allen Teilen des Fruchtkörpers hat positiv (r=0,72; p<0,001) mit steigendem Niveau der Substratanreicherung korreliert. Der Biokonzentrationskoeffizient (BCF) von Silber in den Pilzhüten, Strünken und ganzen Fruchtkörpern zeigte eine negative Korrelation (–0,44     

Influence of nanostructure on titanium corrosion resistance in fluoridated medium

ABSTRACT

Nanocrystalline titanium, mainly owing to its high corrosion resistance, mechanical strength to density ratio and biocompatibility, has a great application potential in dental implantology. However, fluoridated agents commonly used for oral hygiene could have a destructive influence on the titanium protective passive films and lead to the formation of local corrosion damages. In this work, the effect of nanostructuring on titanium corrosion resistance in the concentration of F^? which is typical for toothpastes, was evaluated by different electrochemical and surface characterisation techniques. It was found that nanostructure influences beneficially on titanium corrosion resistance in fluoride solution. Furthermore, the lower increase in nanocrystalline titanium surface roughness in corrosion solutions indicates better stability of passive film formed on its surface.

This paper is part of a thematic issue on Titanium.     

A new F-score gradient-based training rule for the linear model

Pattern Analysis and Applications - Delta rule is a standard, well-established approach to train perceptron recognition model. However, mean squared error, on which it is based, is not suitable...