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.     

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...     

Effect of fermentation conditions on the antioxidant compounds and antioxidant capacity of <Emphasis Type="Italic">Lupinus angustifolius cv. zapaton</Emphasis>

To study the effect of fermentation on the antioxidant compounds and antioxidant capacity of Lupinus angustifolious cv. zapaton, two different types of fermentation processes were performed. Solid-state fermentations in cracked seeds carried out by Aspergillus oryzae, Rhizopus oryzae and Bacillus subtilis and liquid state fermentations in flour and cracked seeds carried out by the microbial population present in the seed (natural fermentation) or by L. plantarum inocula. Antioxidant compounds that were quantified included vitamin C by micellar electrokinetic capillary electrophoresis, vitamin E isomers by high performance liquid chromatography, total phenolic compounds (TPC) by spectrophotometry and reduced glutathione (GSH) by spectrofluorimetry. The antioxidant capacity was analysed by determining the superoxide dismutase-like activity (SOD-like activity), Peroxyl Radical-Trapping Capacity (PRTC) and Trolox Equivalent Antioxidant Capacity (TEAC) and by in vitro methods using unilamellar liposomes of egg yolk phosphatidylcholine (PC). In general, fermentation process produced a reduction in vitamin C, vitamin E activity, GSH and SOD-like activity, however TPC, PRTC, TEAC and inhibition of PC peroxidation increased under most of the fermentation conditions. Optimal results to obtain functional lupin products were achieved in cracked seeds fermented with B. subtilis where increases in TPC content, PRTC, inhibition of PC peroxidation and TEAC content of 490, 669, 492 and 224%, respectively, were found. Also, fermentation carried out with L. plantarum in lupin flours and naturally in cracked seeds caused smaller, although significant (P ≤ 0.05) increases in TPC, PRTC, inhibition of PC and TEAC (80–148, 50–90, 23 and 45–65%, respectively).     

Kinetic study of the antioxidant compounds and antioxidant capacity during germination of Vigna radiata cv. emmerald, Glycinemax cv. jutro and Glycine max cv. merit

The purpose of this study was to determine the antioxidant capacity and the content of antioxidant compounds in raw mung bean seeds and sprouts (Vigna radiata cv. emmerald) germinated for 2, 3, 4, 5 and 7 days and of soybean seeds of Glycine max cv. jutro germinated for 2, 3 and 4 days and of Glycine max cv. merit germinated for 2, 3, 4, 5 and 6 days. Antioxidant compounds, such as vitamin C and E, total phenolic compounds and reduced glutathione (GSH) were studied. Antioxidant capacity was measured by superoxide dismutase-like activity (SOD-like activity), peroxyl radical-trapping capacity (PRTC), trolox equivalent antioxidant capacity (TEAC) and inhibition of lipid peroxidation in unilamellar liposomes of egg yolk phosphatidylcholine (PC). The results indicated that changes in the contents of vitamin C, vitamin E and GSH depended on the type of legume and germination conditions. Sprouts of mung bean and soybeans provided more total phenolic compounds than did raw seeds. The SOD-like activity increased after germination of mung bean seeds for 7 days, by 308%, while no change was observed in sprouts of Glycine max cv. jutro and an increase was observed after 5 and 6 days of germination (∼20%) in Glycine max cv. merit. PRTC and TEAC increased during the germination process and retentions of 28–70% and 11–14%, respectively, for soybean, and 248% and 61%, respectively, for mung bean were observed at the end of germination. The inhibition of lipid peroxidation increased by 389% in 5–7 days’ germination of Vigna radiata cv. emmerald sprouts, and 66% in Glycine max cv. merit sprouts whilst, in Glycine max cv. jutro, germination did not cause changes in lipid peroxidation inhibition. According to the results obtained in this study, germination of mung bean and soybean seeds is a good process for obtaining functional flours with greater antioxidant capacity and more antioxidant compounds than the raw legumes.     

Negation as failure: Careful closure procedure

The aim of this paper is a modification of Minker's Generalized Closed World Assumption that would allow application of the “negation as failure rule” with respect to a set P of (not necessarily all) predicates of a database DB. A careful closure procedure is introduced which, when applied to a database DB, produces a new database DB*, that is used to answer queries about predicates from DB. It is shown that DB* is consistent iff DB is consistent. If P is the set of all predicates from DB and DB does not contain functional symbols, then DB* coincides with Minker's GCWA. The soundness and completeness of the careful closure procedure with respect to a minimal model style semantic is shown. As an inference engine associated with DB* we propose a query evaluation procedure QEP* which is a combination of a method of splitting an indefinite database DB into a disjunction of Horn databases and Clark's query evaluation procedure QEP. Soundness of QEP* with respect to DB* is shown for a broad class of databases.