Recovery of flavonoids from grape skins by enzyme-assisted extraction

Grape skin contains large amounts of different flavonoids so it can be used for their recovery. Optimization of enzyme-assisted extraction of flavonoids was conducted using oenological enzyme preparations with respect to enzyme dosage, temperature, extraction time, pH, and enzyme preparation. Optimal conditions were obtained using enzyme preparation Lallzyme EX-V, at the temperature of 45°C, time of 3 h, pH 2.0, and enzyme dosage of 10.52 mg/g. The new optimized extraction method is less expensive, simple, accurate, and selective for the recovery of simple flavonoids. It is based on an environmentally-friendly extraction solvent which may provide a valuable alternative to conventional methods.     

The Low‐Temperature Cosintering of Cobalt Ferrite and Lead Zirconate Titanate Ceramic Composites

Magneto‐electric (ME) ceramic composites of cobalt ferrite (CoF) and lead zirconate titanate (PZT) were prepared by mechanical mixing of the constituent powders followed by cosintering. The cosintering conditions for nano‐sized CoF and submicrometer‐sized PZT powders were studied in detail. It was found that the CoF powder needs to be presintered at 700°C for 2 h to minimize the differences in the sintering kinetics of the constituent powders. Despite the low cosintering temperatures (900°C–1000°C) the interdiffusion of the cations from both phases was confirmed with energy‐dispersive X‐ray analysis and X‐ray diffraction. Efforts were made to optimize the cosintering conditions to prepare dense ceramic ME composites, which showed the converse ME effect.     

Hydrothermal Synthesis of Manganese Zinc Ferrite Powders from Oxides

Manganese zinc (MnZn) ferrite powders were prepared via the hydrothermal treatment of a homogeneous mixture of the raw oxides (i.e., Fe₂O₃, ZnO, and Mn₃O₄ or MnO) at temperatures of 220°-320°C in air or an inert atmosphere. The final results of the hydrothermal reactions between the raw oxides were fine powders with a heterogeneous phase composition. In addition to lower concentrations of the residual reactants (Fe₂O₃, Mn₃O₄), two types of spinel-structure-based reaction products-ferrite ((Mn²⁺,Zn)Fe₂O₄) and manganate ((Zn,Mn²⁺)Mn₂³⁺O₄)-were detected after the synthesis. The composition of the ferrite products, as well as the ratio of ferrite products to manganate products, were mainly functions of the oxidation state of the manganese that was present during treatment. The oxidation state of manganese during reaction was dependent on the valence of the manganese in the starting manganese oxide and on the atmosphere in the autoclave during reaction. When the hydrothermal reaction was conducted in air, almost-pure zinc ferrite was identified, whereas during reaction in an inert atmosphere, MnZn ferrite was formed. The kinetics of the hydrothermal reactions also were dependent on the oxidation state of manganese, as well as the temperature and specific surface area of the starting Fe₂O₃.     

Hydrothermal Synthesis of Ba-Hexaferrite Nanoparticles

Barium hexaferrite BaFe₁₂O₁₉ nanoparticles with a single-domain size were synthesized using a controlled hydrothermal process involving the LaMer–Dinger principle and the Ostwald ripening mechanism. Nanocrystalline particles of BaFe₁₂O₁₉ were obtained when the molar ratio of the precursor composition Ba(OH)₂·8H₂O/γ-Fe₂O₃ was 0.3 and the concentration of the suspension was about 1 wt%. The as-synthesized crystalline BaFe₁₂O₁₉ platelets approximately 50 nm in length and 5 nm in thickness exhibited a saturation magnetization of 40 Am²/kg.     

Microstructural, XRD and electrical characterization of some thick film resistors

The microstructural and electrical characteristics (sheet resistivities, TCRs, and noise indices) of some 1 k/sq. and 10 k/sq. thick films were evaluated. The conductive phase was determined by X-ray diffraction (XRD) analysis. The microstructures of fired resistors were investigated by scanning electron microscopy (SEM) and analyzed by energy dispersive spectrometry (EDS). Some resistors were fired for a relatively long time at the highest temperature, i.e., 6 h at 850 °C, to allow the reactions in the material to reach equilibria. Sheet resistivities, temperature coefficients of resistivity, and noise indices of these resistors were compared with normally (10 min at 850 °C) fired resistors. After 6 h firing absolute temperature coefficient of resistivity (TCR) values of most resistors increased significantly, while sheet resistivities decreased. Complex impedance analysis showed that in most cases resistors with low noise indices showed nearly ideal resistor response while those with higher noise had a larger imaginary part.     

A characterisation of thick film resistors for strain gauge applications

Some commercial thick film resistors with sheet resistivities from 1 kohm/sq. up to 1 Mohm/sq. were evaluated for strain gauge applications. Temperature coefficients of resistivity, noise indices and gauge factors (GFs) were measured. For the same resistor series GFs and noise indices increase with increasing sheet resistivity. However, both GFs and noise indices are different for resistors with the same nominal sheet resistivity but from different resistor series. The results indicated that the microstructure rather than the different chemical composition of the conductive phase in thick film resistors is the primary reason for the different gauge factors.     

Solid Solubility of Neodymium in BaCeO3

Incorporation of Nd into the BaCeO₃ perovskite structure was studied by quantitative wavelength dispersive spectroscopy-electron probe microanalysis (WDS/EPMA) in combination with scanning electron microscopy (SEM) and X-ray powder diffractometry (XRPD). Highly Nd-doped BaCeO₃ specimens, synthesized by mixed oxide technology, were sintered at 1400°C in ambient air. Concentrations of cations obtained by microanalysis were calculated to the ABO₃ perovskite formula, considering incorporation of Nd at Ba as well as at Ce sites. Nd-BaCeO₃ solid solutions may be represented by the general formula Ba_{1− X} Nd _X Ce_{1− Y} Nd_YO_{3−( Y-X )/2}( V _O)_{( Y-X )/2}. The ratio between Nd incorporated at Ba sites and at Ce sites ( X/Y ) is a function of the starting composition, changing from 1 in the CeO₂-rich part of the BaO-CeO₂-Nd₂O₃ system, to ~0.1 in the BaO-rich part of the system.     

Algorithm for blinds control based on the optimization of blind tilt angle using a genetic algorithm and fuzzy logic

This paper presents the calculation of the power of solar rays that pass through the window of an observed room and their impact on warming up and lighting of the room. The calculations were performed using a mathematical model that takes into account the geographical position of the object, time zone, orientation of windows, day of the year, and current time. This paper also includes the calculation of geometry of the solar radiation and its intensity, artificial light and cooling/heating demands. Based on data from above, the optimization of blind tilt angle was performed to achieve the best possible brightness of the room and energy savings when heating or cooling, depending on ambient temperature. Optimization was performed using a genetic algorithm and fuzzy logic. After an analysis of the results obtained from optimization of the blind tilt angle, an algorithm for blinds control was developed in order to achieve energy savings and comfort in the observed room. Based on the derived conclusions, an UML diagram was made that describes the algorithm for determining optimal blind tilt angle.     

Catalytic Molecular Logic Devices by DNAzyme Displacement

Chemical reactions catalyzed by DNAzymes offer a route to programmable modification of biomolecules for therapeutic purposes. To this end, we have developed a new type of catalytic DNA‐based logic gates in which DNAzyme catalysis is controlled via toehold‐mediated strand displacement reactions. We refer to these as DNAzyme displacement gates. The use of toeholds to guide input binding provides a favorable pathway for input recognition, and the innate catalytic activity of DNAzymes allows amplification of nanomolar input concentrations. We demonstrate detection of arbitrary input sequences by rational introduction of mismatched bases into inhibitor strands. Furthermore, we illustrate the applicability of DNAzyme displacement to compute logic functions involving multiple logic gates. This work will enable sophisticated logical control of a range of biochemical modifications, with applications in pathogen detection and autonomous theranostics.