Inhibitory Effect of GRAS Essential Oils and Plant Extracts on the Growth of Aspergillus westerdijkiae and Aspergillus carbonarius Strains

The effect of essential oils (obtained using hydrodistillation) and plant extracts (ethanolic, aqueous, and hexanic extractions) of 10 different plants cultivated in Brazil were tested using the diffusion agar method, with the objective of evaluating the inhibitory effect of the oils and extracts on the mycelial growth of Aspergillus westerdijkiae NRRL 3174 and A. carbonarius RC 2054 (UNRC). Of the 40 essential oils and plant extracts analyzed, oregano essential oil and plant extract, rosemary essential oil, and the clove ethanolic extract were the best choice to obtain the growth parameters (radial growth rates (mm day⁻¹) and lag phase (h)) due the good results presented and the volume of oil/extract obtained. Comparing all the essential oils and plant extracts that were tested for growth parameters, the best results were obtained for the clove ethanolic extract for both strains assayed. These results demonstrated an outstanding potential use of some of these products in prevention of fungal contamination in food. However, further studies need to be conducted to determine the ability of these oils and extracts to inhibit or reduce ochratoxin A production.     

Immobilization of glucose oxidase on nylon membranes and its application in a flow-through glucose reactor

The immobilization of glucose oxidase on hydrolyzed nylon-6,6 was studied. Various spacers were introduced on the support before the coupling of the enzyme. Best results were obtained when the membrane was covered with denatured bovine serum albumin (BSA) before spacer coupling and immobilization of glucose oxidase (GOD). The influence of various factors (pH, ionic strength, etc.) on the activity of the free and immobilized enzyme was investigated. It was found that the behavior of the fixed glucose oxidase and the free enzyme is very similar. The covalently immobilized enzyme had a lifetime of around 2 months (50% of initial activity).     

Stabilization of Substituted Triazenide Oxides: Synthesis and X‐ray Structural Features of Polymeric Potassium 3‐(4‐carboxylatophenyl)‐1‐methyltriazene N‐oxide‐hydrate, {K[O2C‐C6H4‐N(H)NN(CH3)O]·4H2O}n

3‐(4‐carboxyphenyl)‐1‐methyltriazene N‐oxide reacts with KOH in methanol/pyridine to give {K[O₂C‐C₆H₄‐N(H)NN(CH₃)O]·4H₂O}_n, Potassium‐3‐(4‐carboxylatophenyl)‐1‐methyltriazene N‐oxide). The terminal carboxylato group of the anion does not interact with the cation. In the crystal lattice of {K(C₈H₈N₃O₃)·4H₂O}_n each three of the four water molecules interact with two potassium cations, every K⁺ ion being the centre of six bridging K···O interactions. Potassium cations interact further with the terminal N‐oxigen atom of single [C₈H₈N₃O₃]^? anions achieving two parallel {C₈H₈N₃O₃^?K⁺}_n chains, which are linked through water molecules. The resulting polymeric, one‐dimensional chain, is operated by a screw axis 2₁ parallel to the crystallographic direction [010], along and equidistant to the K⁺ centres. The coordination of the K⁺ centres involves a distortion of the boat conformation of elementary sulfur (S₈) with the ideal C_2v symmetry.     

A proximal-Newton method for unconstrained convex optimization in Hilbert spaces

We propose and study the iteration-complexity of a proximal-Newton method for finding approximate solutions of the problem of minimizing a twice continuously differentiable convex function on a (possibly infinite dimensional) Hilbert space. We prove global convergence rates for obtaining approximate solutions in terms of function/gradient values. Our main results follow from an iteration-complexity study of an (large-step) inexact proximal point method for solving convex minimization problems.     

Transport and thermodynamic properties of a 2DEG in the presence of tilted magnetic field: the influence of Dresselhauss interaction

The effect of Dresselhauss spin-orbit coupling on transport and thermodynamic properties of a non-interacting two-dimensional electron gas (2DEG) is investigated. The Hamiltonian used also includes a tilted magnetic field and a Rashba spin-orbit interaction. The Dresselhauss spin-orbit interaction, likewise the Rashba spin-orbit interaction, introduces a beating pattern in the conductivity tensor and in the magnetization along the field direction. A method to estimate the contribution of the Rashba and Dresselhauss interactions to the beating pattern is given using the periodicity of the beating patterns.     

Preformulation studies to guide the development of raloxifene lipid-based delivery systems

Journal of Thermal Analysis and Calorimetry - The composition and temperature dependence of viscosity and configuration entropy of glasses with chemical composition close to that used for CHROMPIC...