Microencapsulation of Anthocyanins from Grape Skins by Whey Protein Isolates and Different Polymers

Binding of anthocyanin extract from grapes (Feteasc? neagr? variety) by whey protein isolate was first estimated through fluorescence spectroscopy quenching experiments. The data were analyzed using the modified Stern-Volmer equation, allowing the estimation of binding and thermodynamic parameters. The increase of binding constants, accessible fractions, and number of binding sites was highlighted when increasing the temperature, suggesting the presence of the dynamic quenching process. The HPLC analysis allowed the identification of anthocyanin composition of extract and powders, highlighting the presence of the malvidin-3-glucoside as the main anthocyanin. Molecular docking tests provided strong evidence on the involvement of α-lactalbumin and β-lactoglobulin in the tight binding of malvidin-3-glucoside. Further, grape anthocyanins were encapsulated within whey protein isolate and two different polysaccharides (acacia gum and pectin) by coacervation, followed by freeze-drying. The encapsulating efficiency varied between 94 and 99%. Two size smaller particles were obtained in case of microencapsulation in the presence of pectin when compared with acacia gum, as revealed by laser confocal scanning microscopy investigations. Significantly, the experimental variant with pectin allowed the entrapment of a higher amount of flavonoids. The antioxidant activities of the two experimental variants were comparable. The thermal stability experiments evidenced a relatively higher protective effect on anthocyanin degradation in the variant with pectin.     

On a new procedure for finding nonclassical symmetries

A new technique for deriving the determining equations of nonclassical symmetries associated with a partial differential equation system is introduced. The problem is reduced to computing the determining equations of the classical symmetries associated with a related equation with coefficients which depend on the nonclassical symmetry operator. As a consequence, all the symbolic manipulation programs designed for the latter task can also be used to find the determining equations of the nonclassical symmetries, without any adaptation of the program. The algorithm was implemented as the MAPLE routine GENDEFNC and uses the MAPLE package DESOLV (authors Carminati and Vu). As an example, we consider the Huxley partial differential equation.     

Parameter estimation in a thermoelastic composite problem via adjoint formulation and model reduction

Advances in nondestructive material characterization are providing a wealth of information that could be exploited to gain insight into general aspects of material performance and, in particular, discover relationships between microstructure and thermo‐mechanical properties in polycrystalline and other complex composite materials. In order to facilitate the integration of such measurements into existing models, as well as inform new physics‐based predictions, we developed a C++/MPI computational framework for sensitivity analysis and parameter estimation. The framework utilizes a micro‐mechanical modeling based on fast Fourier transforms, direct and adjoint formulations, and Markov chain Monte Carlo sampling techniques. We illustrate the characteristics of this framework and demonstrate its utility by computing the residual stresses arising from thermal expansion of an elastic composite and using data from simulated experiments. We show that the availability of nondestructive 3‐D measurements is crucial to reduce the uncertainty in predictions, emphasizing the importance of an integrated experimental/modeling/data analysis approach for improved material characterization and design. Copyright © 2017 John Wiley & Sons, Ltd.     

Structure and phase diagram of the Na2B4O7-Na3AlF6 system

A complex study was carried out on Na₂B₄O₇-Na₃AlF₆ binary system by means of differential thermal analyses (DTA), X-ray diffraction as well as infrared (IR), and Raman spectroscopy. Although the system exhibits a simple eutectic at 83 wt% Na₂B₄O₇ and T_e = 642°C, interesting structural changes of borate glasses formed have been evidenced by means of IR and Raman spectroscopy. Over 80–100 wt% Na₂B₄O₇ range AlF₆ ^3– anions are diluted in the vitreous matrix without significant structural changes while the further increase of Na₃AlF₆ content diminishes the concentration of BO₄ groups and promotes the appearance of complex anions AlF_x ^(x–3)– (x = 6, 5, 4) as well as the possible new BF₄ ^– and/or BO₃F^4– species.     

Probing the heat‐induced structural changes in bovine serum albumin by fluorescence spectroscopy and molecular modelling

The fluorescence spectroscopy and in silico methods were used to evaluate the structural changes in bovine serum albumin (BSA) over a temperature range of 25–70 °C for 15 min. Experimental results indicated that the polypeptide chain rearrangements at temperatures higher than 40 °C lead to a lower exposure of hydrophobic residues causing the decrease in fluorescence intensity. The nonlinearity of the phase diagram indicated a sequential denaturation process involving several molecular species. The molecular dynamics simulations at the single‐molecule level showed the high stability of the BSA structure, compensating for the entropic costs associated with the prevalent helical folding.     

Methodology for energy aware adaptive management of virtualized data centers

This paper proposes a methodology for energy aware management of virtualized data centers (DC) based on dynamically adapting and scaling the computing capacity to the characteristics of the workload. To assess the energy efficiency of DC operation, we have defined a novel ontological model for representing its energy and performance characteristics and a new metric for aggregating Green and Key Performance Indicators and calculating at run-time the DC Greenness Level. Workload balancing and consolidation is achieved by means of an automated reinforcement learning-based decision process targeting to increase the workload density and to scale down the unused computing resources. Evaluation results show that up to 15.6 % energy savings are obtained on our test bed DC. Tests conducted in a simulated environment show that the time and space overhead of our methodology are within reasonable limits and that by organizing the servers in hierarchical clusters, the methodology can manage highly dynamic workload in large DCs with thousands of servers. The methodology is already implemented in the Green Cloud Scheduler, an official component of the OpenNebula Middleware which is available in the OpenNebula Ecosystem web site to be downloaded and used.     

Influence of deposition technique on the protective properties of epoxy films

The electrochemical impedance spectra, the anodic polarization curves and the time dependence of paint capacitance and paint resistance have been used in this paper to evaluate the protective properties of epoxy films on carbon steel substrate. The coatings were formed using four deposition techniques (brushing, immersion, cathodic and anodic electrodeposition) with the aim to determine the effect of deposition type on the anticorrosive performances of epoxy paint. Interpretation of Nyquist and Bode impedance spectra with the immitance analysis Equivcrt. programme has established an electrical equivalent circuit with two time constants fitted to describe the electrodeposited epoxy/carbon steel system in the 3 % sodium chloride solution and an electrical equivalent circuit with four time constants fitted in case of epoxy films applied by brush or immersion. The anodic polarisation measurements show nobler corrosion potentials and smaller dissolution current densities for the carbon steel in the presence of the electrodeposited films in comparison with epoxy coatings applied by brush or with the immersion technique. The values of the porosity, water uptake, and ionic transport through the film emphasize the higher performances of the electrodeposited films, characterized by uniformity, porosity absence, low water permeability and few conductive pathways.