HS-SPME-GC-MS analysis of volatile aromatic compounds in alcohol related beverages made with mulberry fruits

Wine aroma is one of the most important parameters responsible for its quality, and hence for consumer acceptance. In order to obtain an appropriate technique to study volatile aroma compounds in mulberry wines, headspace-solid phase microextraction (HS-SPME) comb 40°C for 30 min with a 50/30 μm divinylbenzenecarboxen-polydimethylsiloxane (DVB-CAR-PDMS) fiber. Approximately 80 volatile compounds have been quantified in the mulberry wine, pertaining at several chemical groups, mainly higher alcohols, fatty acids, esters, and some volatile phenols whose concentration range from few to 138.36 mg/L. This work describes a novel methodology for the analysis of mulberry wines by HS-SPME coupled to GC-MS. HS-SPME using a 50/30 μm DVB-CAR-PDMS fiber is provided the higher extraction efficiency (p<0.05) for the volatiles including the most esters, higher alcohols, and fatty acids than by the other fibers.     

Effect of peak power in reactive high power impulse magnetron sputtering of titanium dioxide

The effect of peak power in a high power impulse magnetron sputtering (HiPIMS) reactive deposition of TiO₂ films has been studied with respect to the deposition rate and coating properties. With increasing peak power not only the ionization of the sputtered material increases but also their energy. In order to correlate the variation in the ion energy distributions with the film properties, the phase composition, density and optical properties of the films grown with different HiPIMS-parameters have been investigated and compared to a film grown using direct current magnetron sputtering (DCMS). All experiments were performed for constant average power and pulse on time (100 W and 35 μs, respectively), different peak powers were achieved by varying the frequency of pulsing. Ion energy distributions for Ti and O and its dependence on the process conditions have been studied. It was found that films with the highest density and highest refractive index were grown under moderate HiPIMS conditions (moderate peak powers) resulting in only a small loss in mass-deposition rate compared to DCMS. It was further found that TiO₂ films with anatase and rutile phases can be grown at room temperature without substrate heating and without post-deposition annealing.     

Interactions between PVC Geomembranes and Compacted Clays

The interactions between plastic soils and polyvinyl chloride (PVC) geomembranes were studied using a direct shear device under as-compacted conditions. The PVC geomembranes had smooth or textured surfaces, and the soils were of plasticity index (PI) ranging from 35 to 100%. The peak and residual failure envelopes were expressed using Coulomb failure criteria. The adhesion and angle of friction increased for PIs up to 70% and subsequently recorded a decrease. The adhesion is larger for the peak strength compared to the residual strength, but it was the reverse for the angle of friction. The efficiency in terms of adhesion appeared more relevant than that of the angle of friction in expressing the interactions between geomembrane and cohesive soils. The smooth and textured geomembranes showed little difference in results at the residual state.     

Dual transmission model and related spectral content of the fetal heart sounds

A dual transmission model of the fetal heart sounds is presented in which the properties of the signals received on a sensor, installed on the maternal abdominal surface, depend upon the position of the fetus. For a fetus in the occiput anterior position, the predominant spectral content lies in the frequency band 16-50Hz ("impact" mode), but for a fetus in the occiput posterior position, it lies in the frequency band 80-110Hz ("acoustic" mode). Signal processing comprises digital bandpass filtering, matched filtering, Teager energy operator, autocorrelation, and figure of merit algorithms. The digital filter permits the user to select the frequency band that best conforms to the prevailing signal mode. Clinical tests on twelve patients, with some in the occiput anterior and some in the occiput posterior fetal positions, support the validity of the dual transmission model.     

Hysteresis and process stability in reactive high power impulse magnetron sputtering of metal oxides

In the further development of reactive sputter deposition, strategies which allow for stabilization of the transition zone between the metallic and compound modes, elimination of the process hysteresis, and increase of the deposition rate, are of particular interest. In this study, the hysteresis behavior and the characteristics of the transition zone during reactive high power impulse magnetron sputtering (HiPIMS) of Al and Ce targets in an Ar-O₂ atmosphere as a function of the pulsing frequency and the pumping speed are investigated. Comparison with reactive direct current magnetron sputtering (DCMS) reveals that HiPIMS allows for elimination/suppression of the hysteresis and a smoother transition from the metallic to the compound sputtering mode. For the experimental conditions employed in the present study, optimum behavior with respect to the hysteresis width is obtained at frequency values between 2 and 4 kHz, while HiPIMS processes with values below or above this range resemble the DCMS behavior. Al-O films are deposited using both HiPIMS and DCMS. Analysis of the film properties shows that elimination/suppression of the hysteresis in HiPIMS facilitates the growth of stoichiometric and transparent Al₂O₃ at relatively high deposition rates over a wider range of experimental conditions as compared to DCMS.     

n-GaAlAs on p-GaAs heterostructure solar cells grown by molecular beam epitaxy

p-GaAs substrate was used as the starting material in molecular beam epitaxial growth. n-type GaAlAs for heterostructure and n-GaAs capping layer were then grown after a buffer layer deposition on the substrate. The n-GaAlAs on p-GaAs heterostructure solar cells, with active area of 13.25 mm² under 100 mW/cm² AM1 illumination light source, provide a typical output as follows: V_oc=0.73 V, I_sc=6 mA, FF=0.7 and η=23% (active area). Spectral response measurements from 500 to 850 nm reflects the window effect of GaAlAs and band edge of GaAs materials.     

CMOS-based near zero-offset multiple inputs max–min circuits and its applications

CMOS-based near zero-offset multiple inputs maximum circuit and minimum circuits are proposed. The analog signal building blocks including shunt-feedback buffer, voltage-subtraction circuits and current mirrors are deployed for obtained the good performances. This achieved circuit is a simply scheme and able to work with low-power supplies. The input range is obtained around ±600 mV within ±1.5 V power supplies. Near zero-offset and low-output impedance are provided by proposed circuit. The delay of output is less than 5 ns for THD less than 1% and frequency response up to 500 MHz. Half-wave, full-wave rectifiers and 4 bits linear combination Digital-to-Analog Converter (DAC) are raised up to confirm the realistic applications. All performances including the DC-characteristic, frequency response, high-frequency wave output are simulated by PSpice.     

Synthesis of a biocompatible poly(2‐hydroxyethyl methacrylate)–chitosan core–shell hydrogel latex

Core–shell hydrogel latexes, composed of a poly(2‐hydroxyethyl methacrylate) (PHEMA) core chemically coated with chitosan (CS) shell, were synthesized via an emulsifier‐free emulsion polymerization, free radically initiated by a redox couple of tert‐butyl hydroperoxide and amine groups on CS itself. The variation of some polymerization parameters [e.g., polymerization time, CS/2‐hydroxyethyl methacrylate (HEMA) weight ratio, and content of crosslinker] was systematically investigated in this study. We found that the weight ratios between CS and the HEMA monomer influenced the course of polymerization, which was traced by the change in percentage monomer conversions, and the colloidal stability of the PHEMA–CS hydrogel latexes obtained. Moreover, the polymerization time affected their particle sizes and surface charges. For the colloidally stable PHEMA–CS hydrogel latexes, their sizes and charges ranged from 600 to 689 nm and from 32 to 51 mV, respectively. N,N′‐Methylene bisacrylamide was used as a crosslinking agent for the core component; this was found to be able to enhance the hydrogels' thermal stability and water uptake. Moreover, the 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyltetrazolium bromide assay showed that 100% cell viability was achieved during the treatment of the PHEMA–CS latex (0.2–2.5 mg/mL) with Caco‐2 cells. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 40003.     

Characterization of Thermophilic Halotolerant Aeribacillus pallidus TD1 from Tao Dam Hot Spring, Thailand

The bacterial strain TD1 was isolated from Tao Dam hot spring in Thailand. Strain TD1 was Gram positive, rod-shaped, aerobic, motile, and endospore forming. The cell was 2.0-40 μm in length and about 0.4 μm in diameter. The optimum growth occurred at 55-60 °C and at pH 7-8. Strain TD1 was able to grow on medium containing up to 10% NaCl. The DNA G+C content was 38.9 mol%. The cellular fatty acid content was mainly C(16:0), which comprised 25.04% of the total amount of cellular fatty acid. 16S rDNA showed 99% identity to Aeribacillus pallidus DSM 3670(T). Bayesian tree analysis strongly supported the idea that strain TD1 is affiliated with genus Aeribacillus, as Aeribacillus pallidus strain TD1. Although the 16S rDNA of A. pallidus strain TD1 is similar to that of A. pallidus DSM 3670(T), some physiological properties and the cellular fatty acid profiles differ significantly. A. pallidus strain TD1 can produce extracellular pectate lyase, which has not been reported elsewhere for other bacterial strains in the genus Aeribacillus. A. pallidus strain TD1 may be a good candidate as a pectate lyase producer, which may have useful industrial applications.     

Hybrid Plasticizers Enhance Specificity and Sensitivity of an Electrochemical-Based Sensor for Cadmium Detection

In addition to their use as an additive to improve physical properties of solvent polymeric membranes, plasticizers have a considerable impact on the specificity and sensitivity of membrane-modified electrochemical sensors. In this work, we aim at the hybridization of two different plasticizers using the electropolymerization technique in the development of a cadmium(II)-selective electrochemical sensor based on screen-printed gold electrode along with cyclic voltammetric measurement. At this point, we first screen for the primary plasticizer yielding the highest signal using cyclic voltammetry followed by pairing it with the secondary plasticizers giving rise to the most sensitive current response. The results show that the hybridization of DOS and TOTM with 3:1 weight ratio (~137.7-μm-thick membrane) renders a signal that is >26% higher than that from the sensor plasticized by DOS per se in water. The solution of 0.1 mM hydrochloric acid (pH 4) is the optimal supporting electrolyte. In addition, hybrid plasticizers have adequate redox capacity to induce cadmium(II) transfer from bulk solution to the membrane/water interfaces. Conversion of voltammetric signals to semi-integral currents results in linearity with cadmium(II) concentration, indicating the irreversible cadmium(II) transfer to the membrane. The DOS:TOTM hybrid sensor also exhibits high sensitivity, with a limit of detection (LOD) and limit of quantitation (LOQ) of 95 ppb and 288 ppb, respectively, as well as greater specificity towards cadmium(II) than that obtained from the single plasticizer sensor. Furthermore, recovery rates of spiked cadmium(II) in water samples were higher than 97% using the hybrid plasticizer sensor. Unprecedentedly, our work reports that the hybridization of plasticizers serves as ion-to-electron transducer that can improve the sensor performance in cadmium(II) detection.