Electrochemical Determination of Ascorbigen in Sauerkrauts

Ascorbigen (ABG), 2-C-(indol-3-yl)methyl-α-l-xylo-hex-3-ulofuranosono-1,4-lactone, was synthesised and its structure and purity was confirmed by means of ¹H NMR and ¹³ C NMR spectra and HPLC-PDA, respectively. The electrochemical behaviour of ABG was studied by cyclic voltammetry (CV) method for pH within the range of 3.0–7.0 and further characterisation was performed by differential pulse voltammetry (DPV) at pH 5.0. Voltammetric studies of ABG at glassy carbon electrode showed one irreversible oxidation peak (centred at E _p = 0.950 V for pH 5.0). The anodic peak current potential related to the irreversible oxidation of ABG was shifted towards more positive potentials with decreasing pH values. The linear response between concentration of ABG within the range of 0.08–0.75 mM and recorded current was observed. The DPV method was shown to be more sensitive when compared to the CV method. ABG showed a significant reducing activity provided by CV, whilst the antioxidant activity of ABG against O₂^−• was negligible. Electrochemical behaviour of ABG standard was applied successfully for the quantification of natural ABG in sauerkrauts by DPV and HPLC-CoulArray methods. Based on the developed analytical methods, ABG content increased during natural fermentation of cabbage at 0.5% and 1.5% NaCl levels, and results were comparable with those found in the literature.     

Fertilizer dynamics in different tillage and crop rotation systems in a Vertisol in Central Mexico

N-fertilization dynamics and agronomic practices on a Vertisol in central Mexico were evaluated under irrigated conditions: (1) wheat-maize rotation with conventional tillage (CT) and burning of residues (W-M/CT/B, regional control); (2) wheat-beans rotation with CT and incorporation of residues into the soil (W-P/CT/I); (3) wheat-maize rotation with CT and incorporation of residues into the soil (W-M/CT/I); (4) maize-beans rotation bi-annual with CT and incorporation of residues into the soil (M-P/CT/Bi); and (5) wheat-maize, no tillage (NT) and residues left on the soil surface as mulch (W-M/NT/S). ¹⁵N and acetylene inhibition techniques were used to estimate N fertilizer efficiency and losses (N₂ + N₂O). Treatments received 240, 60, and 300 kg N ha⁻¹ for spring maize, beans and winter wheat, as ammonium sulphate enriched with 5.468% atoms ¹⁵N excess. In the spring summer cycle, the fertilizer N recovery ranged from 27% for W-M/NT/S to 68% for M-P/CT/Bi. From the total N-fertilizer applied, only 3 to 9% remained in soil after harvest (W-M/NT/S and W-M/CT/I being the respective extremes). Unaccounted N-fertilizer ranged between 27 and 69%, the highest losses corresponding to W-M/NT/S treatment. Fertilizer N recovery in wheat varied from 19 to 37% (W-M/NT/S–W-M/CT/B). N-fertilizer remaining in soil was 14 to 24% (W-M/NT/S – W-M/CT/I). N₂ and N₂O emissions were higher in the no tillage system. Emissions ranged from 3 to 28 kg N ha⁻¹ for W-P/CT/I and W-M/NT/S, respectively. The best treatments were those in which residues were incorporated resulting in N immobilization in top soil (0–15 cm), small N gas losses, and higher soil organic matter, these treatments were W-P/CT/I, W-M/CT/I.     

Preparation of a poly-alkylamine surface-functionalized carbon with excellent performance as a Pd(II) scavenger

A stable, extensive amine functionalization was introduced on the surface of an activated carbon (AC) through very effective grafting of a polyethyleneimine layer onto the AC surface. The procedures used are simple, sustainable and easily scalable. Among the large variety of possible applications that the polyamine functionality confers to the AC, its outstanding properties as Pd(II) adsorbent are here presented.     

Improved extraction of carrageenan from red seaweed (Chondracantus canaliculatus) using ultrasound-assisted methods and evaluation of the yield,physicochemical properties and functional groups

Food Science and Biotechnology - Red seaweed Chondracanthus canaliculatus, an underexploited algae species, was used as a potential source for the obtaining of carrageenan. Seaweed was treated...     

Quantum Statistical Properties of Coupled Nonlinear Oscillators with Losses

Abstract

The statistical properties of two coupled nonlinear oscillators including losses are discussed using the statistics for the generalized superposition of coherent fields and quantum noise. Exact and approximate formulae for squeezing of vacuum fluctuations are derived. The photon statistics are shown to be Poissonian from the nonlinear dynamics of the lossless case. Non-classical behaviour is degraded by noise.     

The bounds on the solutions of certain two-dimensional delay dynamic systems on time scales

By means of a new linear Gronwall–Bellman inequality on time scales and an elementary inequality, the bounds on the solutions of a class of new nonlinear two-dimensional dynamic systems on time scales are obtained.     

Goal priming and eating behavior: Enhancing self-regulation by environmental cues.

Objective: Several lines of research have shown that the confrontation with attractive food can trigger overeating, especially in restrained eaters. This effect may be driven by a hedonic orientation toward food which temporarily overrules the goal of dieting in the regulation of behavior. The present study was designed to provide an experimental demonstration of this effect in a naturalistic setting, and to show that reactivating the goal of dieting by a subtle prime in the environment can help restrained eaters to regulate their eating behavior in tempting situations. Design: In a local store where the smell of grilled chicken was present, we observed the number of free meat snacks customers sampled from a tray after they had been primed with the dieting goal or not. Main Outcome Measures: Number of snacks consumed. Results: Consistent with hypotheses, restrained eaters ate more than unrestrained eaters in the control condition. However, they reduced their eating behavior when primed with dieting, whereas this manipulation did not affect unrestrained eaters. Conclusion: This study shows that unobtrusively priming the goal of dieting can enhance self-regulation in tempting eating situations. These results are discussed in the context of recent advances in our understanding of nonconscious behavior regulation and their applications to health behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ion implantation of oxygen and nitrogen in CpTi

A study of the plasma ion implantation (PIII) of commercially pure titanium (CpTi) at a low voltage (<4 kV) is presented. The processed samples were treated in divers mixtures of O and N in order to achieve biocompatible oxidized and nitrided layers as well as to enhance their superficial hardness. In this way, the low wearing resistance of CpTi can be avoided while creating a biocompatible rutile phase titanium oxide layer for a better bone integration. A form of synergy associated to the dependence of microhardness on the implanted layer disposition is identified. Thus, an upper rutile layer is immediately followed by another one, in which titanium, a nitride (TiN_0.26) and rutile coexist. The latter leads to a superior microhardness performance. Most of all these surface treatments of titanium, when applying an 80%N–20%O mixture, yield higher corrosion resistance parameters with respect to the main metallic materials used in prosthetics, including the Co–Cr–Mo alloys, albeit excluding CpTi.