Use of Zebrafish Embryo Assay to Evaluate Toxicity and Safety of Bioreactor-Grown Exopolysaccharides and Endopolysaccharides from European Ganoderma applanatum Mycelium for Future Aquaculture Applications

Natural mycelial exopolysaccharide (EPS) and endopolysaccharide (ENS) extracted from bioreactor-cultivated European Ganoderma applanatum mushrooms are of potential high commercial value for both food and adjacent biopharmaceutical industries. In order to evaluate their potential toxicity for aquaculture application, both EPS (0.01–10 mg/mL) and ENS (0.01–10 mg/mL) extracts were tested for Zebrafish Embryo Toxicity (ZFET); early development effects on Zebrafish Embryos (ZE) were also analyzed between 24 and 120 h post-fertilization (HPF). Both EPS and ENS are considered non-toxic with LC₅₀ of 1.41 mg/mL and 0.87 mg/mL respectively. Both EPS and ENS did not delay hatching and teratogenic defect towards ZE with <1.0 mg/mL, respectively. No significant changes in the ZE heart rate were detected following treatment with the two compounds tested (EPS: 0.01–10 mg/mL: 176.44 ± 0.77 beats/min and ENS: 0.01–10 mg/mL: 148.44 ± 17.75 beats/min) compared to normal ZE (120–180 beats/min). These initial findings support future pre-clinical trials in adult fish models with view to safely using EPS and ENS as potential feed supplements for supplements for development of the aquaculture industry.     

Electrical and morphological analysis of chitosan:AgTf solid electrolyte

Solution cast technique is employed to prepare solid polymer electrolyte films based on chitosan (host polymer) and silver triflate (AgCF₃SO₃, doping salt) using (1%) acetic acid as a common solvent. The effect of salt concentration on both EP and bulk materials dielectric properties has been analyzed. Physically the original relationship between the bulk dielectric constant and DC conductivity has been interpreted. It is demonstrated that the dielectric constant and dielectric loss values decrease at higher temperatures due to the reduction of silver ions. Scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDAX) indicate the presence of metallic silver particles. The ac conductivity spectra shows three distinct regions and obeys the Jonscher's power law at high frequency regions. The temperature dependence of frequency exponent (s) shows the crossover from CBH model to SP model.     

Vital parameters for high gamma-aminobutyric acid (GABA) production by an industrial soy sauce koji Aspergillus oryzae NSK in submerged-liquid fermentation

Food Science and Biotechnology - In submerged-liquid fermentation, seven key parameters were assessed using one-factor-at-a-time to obtain the highest GABA yield using an industrial soy sauce koji...     

Charge transport in silver chalcogenides in the region of phase transition

Data on the σ(T), R(T), and U(T) dependences in Ag₂Te, Ag₂Se, and Ag₂S in the region of the phase transition are analyzed. It is found that the phase transition in Ag₂Te is accompanied by a decrease in the electron concentration and this transition in Ag₂Se is accompanied by an increase in this concentration. The concentration of intrinsic charge carriers in Ag₂Te decreases by a factor of 4 as a result of the phase transition and increases by a factor of 2 in Ag₂Se. The effect of variation in the energy-band parameters in the region of phase transition on the electron mobility is considered. It is established that, in Ag₂Te and Ag₂S, electrons are scattered by optical phonons in the region of the phase transition, while electrons are scattered by acoustic phonons in the α and β phases. It is assumed that the anomalously large increase in σ and U in Ag₂S as a result of the phase transition is caused by an increase in the concentration n and a simultaneous decrease in σ _g and m _n ^* by a factor of about 2.     

Influence of Hydrogen Bonding on Low Critical Micellar Concentration Value and Formation of Giant Vesicle of Triazole-Contained Amphiphile

An amphiphile molecule consisting of triazole moiety has been thoroughly investigated using different approaches in its aqueous condition. The studies have discovered the explicit function of its heteroaromatic ability in molecular self-assembling. From the fluorescence evidence, the triazole-based amphiphile has shown that the aggregation-induced emission behavior is mainly due to the triazolyl. It suggests that the triazole is directly involved in the self-assembling mechanism through an intermolecular interaction. This interaction can be verified by the shifting of proton frequency of the triazole, which is clearly shown by the constant frequency of the proton above the critical micellar concentration (CMC) value. The frequency suggests the establishing hydrogen bond that occurred between the hydrogen and the second nitrogen of the adjacent triazole. These results are consistent with the micellization of the molecule which was determined at a very low CMC value (0.1 mM). The absorbance and optical polarizing microscopy results also support the evidence of the growth of giant vesicles produced from the neutralization of the amphiphile. The formation of stable giant vesicles at neutral pH demonstrates the immediate strong hydrogen bonding connections within the triazoles layer in the bilayer. The discovery reveals that internal hydrogen bonds formed from a heteroaromatic with the appropriate molecular arrangement can promote self-aggregation and enhance overall stability.     

New process for catalyst-free biodiesel production using subcritical acetic acid and supercritical methanol

The production of glycerol as a by-product is unavoidable in the current conventional biodiesel manufacturing processes. Since biodiesel production is expected to increase in the near future, effective utilization of glycerol will become an issue of interest. In this study, therefore, a process consisting of subcritical acetic acid treatment to convert rapeseed oil to fatty acids and triacetin followed by conversion of the obtained fatty acids to their fatty acid methyl esters in supercritical methanol treatment was investigated. The obtained results clearly revealed that this two-step reaction could proceed effectively at a high reaction rate, and that fatty acid methyl esters and triacetin could be obtained under milder reaction condition than the one-step process utilizing supercritical methyl acetate and supercritical methanol.     

Fabrication and characterization of Si quantum dots and SiO(2) tunnel barriers grown by a controlled oxidation process

The control of the growth of silicon dioxide (SiO(2)) and the formation of quantum dots (QDs) play an important role in the fabrication of single-electron transistors (SETs). In this work, SET?structures were fabricated using a systematic oxidation technique known as the pattern-dependent oxidation (PADOX) process. For comparison, two oxidation processes using conventional furnace and rapid thermal processing (RTP) were used. The oxidation temperature for both oxidation processes was set at 1000?°C and the oxygen flow rate in the furnace was set at 1?l?min(-1). The nanostructures were characterized using AFM, SEM and TEM to determine the quality and the stoichiometry of the Si QDs and the oxides. The oxidation rate using a furnace is 0.36?nm?s(-1), significantly lower than the RTP value which is 2.16?nm?s(-1). Meanwhile, the oxygen contents in SiO(2) grown by furnace and RTP are approximately the?same.     

Production of biodiesel with glycerol carbonate by non‐catalytic supercritical dimethyl carbonate

New biodiesel production processes comprising one‐step and two‐step supercritical dimethyl carbonate methods have been pioneered. The use of dimethyl carbonate allows the reaction conditions to be mild and thus avoid unwanted deterioration of substrates during reaction. In this process, without any catalyst applied, supercritical dimethyl carbonate converts triglycerides (rapeseed oil) into fatty acid methyl esters (FAME) along with glycerol carbonate as a value‐added by‐product, instead of glycerol. Free fatty acids could be also converted into FAME so that the total yield of biodiesel for both methods resulted in over 96 wt%. In addition, the produced FAME satisfy the fuel requirements for the international standards of biodiesel specification.     

3D electro‐thermal modelling and experimental validation of lithium polymer‐based batteries for automotive applications

This article presents an electro‐thermal model of a stack of three lithium ion batteries for automotive applications. This tool can help to predict thermal behaviour of battery cells inside a stack. The open source software OpenFOAM provides the possibility to add heat generation because of Joule losses in a CFD model. Heat sources are introduced at the connectors and are calculated as a function of battery discharge current and internal resistance. The internal resistance is described in function of temperature. Simulation results are validated against experimental results with regard to cooling air flow field characteristic and thermal behaviour of the cell surface. The validation shows that the simulation is capable to anticipate air flow field characteristics inside the battery box. It also predicts correctly the thermal behaviour of the battery cells for various discharge rates and different cooling system conditions. The simulation supports the observation that batteries have a higher temperature close to the connectors and that the temperature increase depends highly on discharge rate and cooling system conditions. Copyright © 2016 John Wiley & Sons, Ltd.     

Cavitation during high-temperature deformation in Al–Mg alloys

It has recently been revealed that high-density pre-existing hydrogen micropores, formed during production processes, exhibit premature growth and coalescence under external loading at room temperature, thereby inducing ductile fracture. This process is incidentally supplemented by the well-established ductile fracture mechanism based on particle damage. It is reasonable to assume that the pre-existing hydrogen micropores may also contribute to damage evolution at high temperatures. In the present study, synchrotron X-ray microtomography was applied to the in situ observation of deformation and fracture in Al–Mg alloys at a high temperature. High-density hydrogen micropores were observed in the alloys. Flow localization controlled deformation through the mechanism of solute drag creep. A combined effect of grain boundary sliding and heterogeneous nucleation on particles was also confirmed to accelerate the growth of pre-existing hydrogen micropores and cavities. Although continuous nucleation occurred together with the growth of pre-existing hydrogen micropores, the effects of the pre-existing hydrogen micropores, especially those located on grain boundaries, were predominant in the overall damage evolution. It seemed likely that supersaturated hydrogen in the aluminum alloys might also make an appreciable contribution to cavitation during high-temperature loading.