Microwave irradiation under different pH conditions induced a decrease in β-lactoglobulin antigenicity

Whey proteins adjusted at pH values 2, 4.6, 9 and at the natural milk pH (pH 6.8) were subjected to microwave irradiation at 300 W for 20 min or 700 W for 10 min. The protein composition of treated and native whey proteins were evaluated by Lowry’s method and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The ability of treated whey to bind IgG polyclonal antibody was determined by an enzyme-linked immunosorbent assay (ELISA) using sera obtained from rabbit immunized to β-Lactoglobulin (β-Lg). Significantly higher losses in soluble protein concentrations were observed for microwave irradiated whey proteins at pH value 4.6 (35.6% at 300 W and 44.33% at 700 W) (P < 0.0001) compared with those irradiated at the natural milk pH (26% at 300 or 700 W). The electrophoretic patterns of these proteins revealed a considerable decrease in intensity of the band corresponding to α-lactalbumin but only a slight modification was observed for the electrophoretic profiles of β-lactoglobulin. The data obtained with a rabbit anti-β-lactoglobulin immunoglobulin indicated a low antigenic response for microwave-irradiated whey proteins at the natural milk pH (up to 29.32% as well as 300–700 W) (P < 0.001). The lowest antigenicity was observed for samples adjusted to pH 4.6 followed by microwave irradiation at 300 or 700 W (46.99% at 300 W and 41.16% at 700 W) (P < 0.0001).     

The Price and Trading Volume Dynamics Relationship in the EEX Power Market: A Wavelet Modeling

This paper examines the dynamic relationship between power spot prices and related trading volumes in one of the most emergent energy markets. Traditionally, investigating the bivariate stochastic processes has been dominated by linear econometrical methods that proved helpful especially in finance. However, when dealing with intradaily power data, we cannot rely on models developed for financial or other commodity markets. Therefore, wavelet transforms are applied for power markets data to search for and decode nonlinear regularities and hidden patterns existing between the variables. Given its ability to decompose the time series into their time scale components and thus to reveal structure at different time horizons, wavelets are useful in analyzing situations in which the degree of association between processes is likely to change with the time-horizon. Therefore, a wavelet-based cross-analysis is performed between prices and trading volume time series. On the same basis, causality tests and out-of-sample forecasting tasks are carried out to empirically the strong relationship between the two investigated time series.     

A probabilistic approach to setting distance relays in transmissionnetworks

The setting of back-up zones in distance relays has to deal with fault current infeeds between the relay and remote faults. Traditional approaches to this problem are conservative, some times leaving portions of a power system without sensitive or selective back-up protection. In this paper, a probabilistic model for the relay errors resulting from the variation of the infeeds is developed. Other measurement inaccuracies are also considered in order to build a probabilistic approach to setting all zones of distance relays. The developed concepts are associated to automatic tools for computer aided protection coordination and applied to the Portuguese transmission grid     

Boron doping of amorphous hydrogenated silicon films prepared by r.f. sputtering

Amorphous hydrogenated silicon (a-Si:H) films 1 μm thick were prepared at 190 and 250 °C by r.f. sputtering in an Ar-H₂-B₂H₆ gas mixture whose composition Y_g = [B₂H₆]/([Ar] + [H₂]) was varied between zero and 10^-2. Measurements of the optical gap E₀ and the dark conductivity σ_d give evidence for the existence of three regions as a function of Y_g. Up to Y_g = 10^-6, the conductivity activation energy E_a increases towards the intrinsic value E₀/2. For Y_g between 10^-6 and 10^-3, E₀ and E_a decrease to 1.5 eV and 0.4 eV respectively, indicating that efficient p-type doping is achieved. At higher diborane concentrations a boron-rich a-Si:B:H compound is formed which is not conductive. The photoconductivity ratio σ_ph/σ_d reaches its maximum value (of 10³) at Y_g ≈ 10^-6 and drops to unity for Y_g ? 10^-4. The loss in σ_ph is related to an increase in the density of states near the Fermi level as revealed by the onset of an important hopping conductivity on the σ_d curves.     

A study of SS size distribution during runoff and fractionation of phosphates depending on soil size in agricultural watershed.

Characterization of the differences and algal-available fractions of P in soils, suspended solids, and bottom sediments have been the main topics of research during the past decade. However, the size distribution and properties of particulate matter in runoff have not been much studied in Japan. Here we study particle size distribution during runoff and the chemical characteristics of P in each soil size fraction and relate them to land use. The temporal variation of particulate sizes during rain events is different in each watershed. Most particles have the size in the range of 10-100 microm. Also, the percentage of BAP in TP as well as percentage of PCOD in SS also varies temporally and spatially during runoff. To investigate how soil particles characteristics depend on land use, soil samples from two watersheds are examined. For particle size distribution and specific gravity, no significant difference among watersheds is found. However, C, N, and P content are indirectly proportional to the particle size, which means smaller particle size results in larger. H2O-extracted P, NH4Cl-extracted P, NAI-P, Apatite-P, Organic-P, and TP contents in each soil particle sample vary depending on particle size, land use, and watershed.     

Effects of reaction time and citric acid contents on the morphologies of BaCO3 via PVP-assisted method

BaCO₃ with different morphologies, such as dumbbell-like, pillar-like, peanut-like and ellipsoid-like have been successfully synthesized using citric acid (CA) as chelating ligand via a simple polyvinylpyrrolidone (PVP)-assisted method. The effects of the pH of the starting solutions, reaction time and the molar ratio of CA/Ba²⁺ on the morphologies of BaCO₃ were investigated. X-ray diffraction (XRD), transmission electron microscope (TEM) and the infrared (IR) spectrum of the sample are used to characterize the obtained products.     

Extraction of polymer stress–strain behavior in the presence of self‐heating by the use of a simple model for the elastic–plastic deformation

Polymer materials are well known to be sensitive to strain rate and temperature. Self‐heating and friction effects also play an important role in the mechanical response of these materials. Numerous constitutive laws and phenomenological models have been developed to take into account these dependencies. This article proposes a simplified phenomenological model based on a mapping technique for the strain rate and temperature dependence. The effects of friction and adiabatic heating are also analyzed in this work. Relatively good results are obtained compared to experimental results for polypropylene and polychlorotrifluoroethylene. A parametric investigation of the effects of the interfacial equivalent stress (between the specimen and the compressive bars) and the fraction of plastic work converted into heat was performed. This parametric study allowed for a good approximation of these two parameters for the two studied polymers. POLYM. ENG. SCI., 55:2474–2481, 2015. © 2015 Society of Plastics Engineers