Supercritical fluid deposition of vanadium oxide on multi-walled carbon nanotube buckypaper for supercapacitor electrode application

Composite electrodes were fabricated for supercapacitor applications by depositing vanadium oxide onto multi-walled carbon nanotube (MWCNT) buckypaper using supercritical fluid deposition (SFD). The deposited thin vanadium oxide layer showed amorphous structure with excellent uniformity. In aqueous KCl electrolyte, the vanadium oxide exhibited a constant pseudo-capacitance of ～ 1024 F g(-1), which was independent of the oxide material loading (up to 6.92 wt%) and voltage scan rate (up to 100 mV s(-1)). The highest specific electrode capacitance achieved was ～ 85 F g(-1), which was almost four times that of the pristine buckypaper electrode.     

Real-time monitoring of plasmonic evolution in thick Ag:SiO(2) films: nanocomposite optical tuning

An in situ optical microspectroscopy study of the surface plasmon resonance (SPR) evolution of Ag nanoparticles (NPs) embedded in thick SiO(2) films deposited on soda-lime glass has been conducted during thermal processing in air. The temperature and time dependences of the SPR were analyzed in the context of Mie extinction and crystal growth theories and were discussed along with consideration of oxidation processes and film/substrate physicochemical interactions. At relatively high temperatures, Ag NPs were indicated to grow first through a diffusion-based process and subsequently via Ostwald ripening. At lower temperatures, an initial decrease in Ag particle size was indicated due to oxidation, followed by NP diffusion-based growth. The growth and oxidation stages appeared temperature and time dependent, allowing for the tuning of material properties. The product of Ag NP oxidation was revealed by photoluminescence spectroscopy performed ex situ as single Ag(+) ions. The oxidative effect of the air atmosphere on Ag NPs was shown to be ultimately circumvented by the thick nanocomposite film. The phenomenon was explained on the basis of the displacement of the Ag/Ag(+) redox equilibrium toward Ag NP stability after ion migration toward the substrate being self-constrained. In addition, the current spectroscopic approach has been proposed for estimating the activation energy for silver diffusion in the SiO(2) matrix.     

Biogenic amines in pressurized vacuum-packaged cooked sliced ham under different chilled storage conditions

This work was undertaken to study how storage conditions (at constant temperatures of 2±1 and 12±1°C and temperature fluctuations at 7±5°C) affect microbial development and the production of biogenic amines in vacuum-packaged cooked sliced ham subjected to high pressure (400MPa/10min/30°C). Initially, the product exhibited low levels of contamination. Microbiological changes during storage depend on the processing (non-pressure and pressure treatment) and the chilled storage conditions. Generally, microbial growth in pressurized samples was similar to that in the non-pressurized samples, although the total viable count and lactic flora were lower and growth was delayed. Processing and storage conditions affected the formation of each amine differently. The most important changes were in tyramine, which formed more quickly in non-pressurized products stored at 12°C and with temperature fluctuations. The formation of biogenic amines in these products can be prevented not only by ensuring good manufacturing practices and applying high pressure but also by ensuring the right chilled storage conditions.     

Microbiological changes in pressurized, prepackaged sliced cooked ham

This was a study of the influence of high-pressure conditions (200 and 400 MPa, 5 and 20 min, 7 degrees C) on microbiological quality and water-binding properties of vacuum-prepackaged sliced cooked ham and how this affects microbiological changes during chilled storage (2 degrees C). Pressurization caused a degree of microbiological inactivation, which increased with pressure level and processing time. Pressurization at 400 MPa significantly reduced the total viable count and lactic acid bacteria to the extent that after 20 min no Enterobacteriaceae, Baird Parker flora, or Brochothrix thermosphacta were detected throughout any of the chilled storage periods studied. In general, gram-positive flora was more resistant to pressure than gram-negative flora. The fact that high pressure (400 MPa) causes considerable inactivation of microorganisms could be used to prolong the shelf life of vacuum-prepackaged sliced cooked ham.     

Fluorescent polarization immunoassay for sulphadiazine using a high specificity antibody

A rapid and sensitive fluorescent‐labelled polarization immunoassay for sulphadiazine (SDZ) is reported. Fluorescein‐labelled tracers were synthesized and a specific SDZ antibody has been used in the development of the method. The influence of the fluorescent label type on the immunoassay sensitivity was investigated. Homologous and non‐homologous tracer – antiserum combinations were varied to provide increased sensitivity of the immunoassay. A detection limit of 0.2 ng mL^?1 for SDZ in 50 μL aqueous sample has been achieved. The cross‐reactivity of other sulphonamide drugs has also been examined.     

Prevention of clinical mastitis with barium selenate in dairy goats from a selenium-deficient area

Mastitis is one of the most negative factors involved in the economy of dairy goat farms. The effect of selenium on mammary gland resistance to infectious diseases has been demonstrated. This work evaluates the efficacy of a slow-release Se salt (barium selenate) to reduce the incidence of clinical mastitis in goats reared on Se-deficient areas. Six hundred milking goats of the Malagueña breed, from 4 commercial dairy farms located in a Se-deficient area, were randomly allotted to 2 groups: treated group (given a subcutaneous injection of barium selenate at a dose of 1 mg of Se/kg of body weight 15 d before mating) and control group (no supplement). During the lactation the does were monitored to assess the occurrence of clinical mastitis by physical examination, California Mastitis Test performance, and microbiological study. The Se content of the ration consumed previously by the animals did not meet the requirements for dairy goats. The Se injection significantly increased glutathione peroxidase activity in the treated group and had evident beneficial effects in the subsequent lactation. The somatic cell count and the incidence of clinical mastitis were significantly lower in the treated group than in the control group. However, no significant differences were found for milk composition. Thus, in Se-deficient areas, the supplementation with Se of any source in programs for prevention of clinical mastitis and improvement of milk quality is strongly recommended.     

Physical properties of enzyme-supplemented doughs and relationship with bread quality parameters

The textural properties of wheat doughs made with different commercial amylases, xylanases/pentosanases, lipases and glucose-oxidase, singly and in mixed combinations, were investigated. Parameters from the texture profile analysis (TPA) and measurement of stickiness (Chen and Hoseney test) were determined after mixing the dough and after it had rested for 3.5 h. Resting of doughs led to softer and less cohesive doughs, with higher adhesive properties. Enzymes acted quickly and induced significant changes in the textural properties of doughs immediately after mixing. The influence of enzymes continued during resting. Xylanases/pentosanases substantially reduced dough consistency and increased stickiness, while addition of glucose-oxidase and specific lipases overcame these effects. Strong correlations could be established between different TPA parameters and stickiness and bread quality characteristics (i.e. volume, density and texture). Bread quality could be described by a single or multiple linear combination of textural variables.     

Characterizing and quantilying controls on arsenic solubility over a pH range of 1-11 in a uranium mill-scale experiment

A mill-scale hydrometallurgical experiment (2700 m3 of effluent treated/day) was conducted for three months at the Rabbit Lake uranium mine site located in northern Saskatchewan, Canada, to determine the controls on the solubility of dissolved arsenic over a pH range of 1-11 and to develop a thermodynamic database for the dominant mineralogical controls on arsenic in the mill and the resulting mill tailings. The arsenic concentrations in the mill ranged from 526 mg/L at pH 1.0 (initial) to 1.34 mg/L at pH 10.8 (final discharge). Geochemical modeling of the chemistry data shows that arsenic solubility is controlled by the formation of scorodite (FeAsO4-2H2O) from pH 2.4 to pH 3.1, with 99.8% of dissolved arsenic precipitated as scorodite. Model results show that scorodite is unstable (releasing arsenic back in to solution) above pH 3.1 and arsenic adsorption to the surface of 2-line ferrihydrite is the dominant controlling factor in the solubility of arsenic from pH 3.2 to pH 11.0, with 99.8% of dissolved arsenic removed from solution via this mechanism. Finally, model results show -0.2% of the total dissolved arsenic adsorbs to the surface of amorphous aluminum hydroxide from pH 5.0 to pH 8.0. Minor alterations to the thermodynamic properties of arsenite and arsenate adsorption to 2-line ferrihydrite allowed the fit between measured mill-scale and modeled concentrations for the pH range of 3.2-11.0 to be optimized.