Effect of ultrasonic treatment on the polyphenol content and antioxidant capacity of extract from defatted hemp,flax and canola seed cakes

The effectiveness of ultrasonic extraction of phenolics and flavonoids from defatted hemp, flax and canola seed cakes was compared to the conventional extraction method. Ultrasonic treatment at room temperature showed increased polyphenol extraction yield and antioxidant capacity by two-fold over the conventional extraction method. Different combinations of ultrasonic treatment parameters consisting of solvent volume (25, 50, 75 and 100 mL), extraction time (20, 30 and 40 min) and temperature (40, 50, 60 and 70 °C) were selected for polyphenol extractions from the seed cakes. The chosen parameters had a significant effect (p < 0.05) on the polyphenol extraction yield and subsequent antioxidant capacity from the seed cakes. Application of heat during ultrasonic extraction yielded higher polyphenol content in extracts compared to the non-heated extraction. From an orthogonal design test, the best combination of parameters was 50 mL of solvent volume, 20 min of extraction time and 70 °C of ultrasonic temperature.     

Ultrasound-assisted polysaccharide extraction from Cercis chinensis and properites,antioxidant activity of polysaccharide

The purpose of the study was to improve the extraction of polysaccharide from the leaves of Cercis chinensis Bunge using ultrasound, and compare the difference between boiling and ultrasound extraction in terms of polysaccharide content, monosaccharide compounds, and evaluate how the factors affected the bioactivity. The best conditions, according to the single factor experiments and the Box-Bohnken design (BBD), were an intensity of ultrasound of 180 W, duration of extraction of 40 min, proportion of water to material of 15:1 (g/g), and a higher polysaccharide yield of 20.02 ± 0.55 (mg/g) than in boiling extraction (16.09 ± 0.82 mg/g). The antioxidative experiment suggested the polysaccharide by ultrasound exhibited higher DPPH, hydroxyl radical scavenging capacities, and reducing power at 1.2–1.4 mg/mL, which was superior to the boiling polysaccharide. Further analysis showed that the ultrasonic purified polysaccharides like Gla, N-Glu, and GluA contained more total sugar and uronic acids than the boiling method did. This may indicate that the ultrasonic isolation of the polysaccharides increase the antioxidant activity of the polysaccharides.     

Ultrasonic-assisted preparation of eucalyptus oil nanoemulsion: Process optimization,in vitro digestive stability,and anti-Escherichia coli activity

Eucalyptus oil (EO) is a natural and effective antimicrobial agent; however, it has disadvantages such as poor water solubility and instability. The aim of this study was to investigate the effect of process vessels and preparation process parameters on the particle size of the emulsion droplets using ultrasonic technique and response surface methodology to prepare eucalyptus oil nanoemulsion (EONE). The optimal sonication process parameters in conical centrifuge tubes were confirmed: sonication distance of 0.9 cm, sonication amplitude of 18%, and sonication time of 2 min. Under these conditions, the particle size of EONE was 18.96 ± 4.66 nm, the polydispersity index was 0.39 ± 0.09, and the zeta potential was −31.17 ± 2.15 mV. In addition, the changes in particle size, potential, micromorphology, and anti-Escherichia coli activity of EONE during digestion were investigated by in vitro simulated digestion. The emulsion was stable in simulated salivary fluid, tended to aggregate in simulated gastric fluid, and increased in particle size and potential value in simulated intestinal fluid. EONE showed higher anti-E. coli activity than EO by simulated digestion. These results provide a useful reference for the in vivo antimicrobial application of the essential oil.     

Effect of sonication,microwaves and high-pressure processing on ACE-inhibitory activity and antioxidant potential of Cheddar cheese during ripening

Dairy processing provides acceptable safety and shelf-life to final products, and improves their bioactivity. The present study evaluated the potential of different milk processing techniques to improve the antioxidant and angiotensin-I converting enzyme (ACE)-inhibitory activity of Cheddar cheese, during ripening. Cheese was made from milk subjected to different pre-treatments (C = untreated control, US-1 = ultrasonication, specific energy = 23 J/g, 20 kHz frequency; US-2 = Ultrasonication specific energy = 41 J/g, 20 kHz; HPP = high-pressure processing, 400 MPa for 15 min, at temperature < 40 °C; MW = microwave, temperature<40 °C, specific energy = 86.5 J/g) and analysed after ripening for 0, 3, 6 and 9 months. The results showed that the rate of proteolysis during both cheese making and subsequent ripening was significantly affected by the pre-treatment. Antioxidant activity and ACE-inhibitory potential of cheeses made from pre-treated milk significantly increased (p < 0.05) in the following order: US-2 > HPP > US-1 > MW > C. These findings demonstrate the possibility of using ultrasound, microwaves or high-pressure processing as pre-treatments to improve the nutritional attributes of cheese.     

Effects of ultrasonic assisted high-temperature cooking method on the physicochemical structure characteristics and in vitro antioxidant capacities of dietary fiber from Dendrocalamus brandisii Munro shoots

In this study, the ultrasonic assisted high-temperature cooking extraction method of soluble dietary fiber from bamboo shoots was optimized by response surface methodology, and the effects of ultrasonic assisted high-temperature cooking extraction on the structural characteristics, physicochemical properties and antioxidant activity of soluble dietary fiber (SDF) from bamboo shoots were evaluated. The yield of modified UH-SDF¹ was significantly higher than that of untreated D-SDF². FTIR and XRD confirmed that UH-SDF had more hydrophilic groups and higher crystallinity (28.73 %), resulting in better thermal stability. SEM observation showed that UH-SDF exhibited a more loose microstructure, and the particle size of UH-SDF (601.52 μm) was significantly smaller than that of D-SDF (242.59 μm), so UH-SDF had a larger specific surface area. In addition, UH-SDF has stronger water holding capacity, water swelling capacity and oil holding capacity than D-SDF. The DPPH radical and hydroxyl radical scavenging rates of UH-SDF were 8.91 % and 7.49 % higher than those of D-SDF. In addition, the reducing ability of UH-SDF was higher than that of D-SDF, which had better antioxidant activity. In summary, UH-SDF has the potential to be developed as an anti-inflammatory functional food.     

Ultrasound-alkaline combined extraction improves the release of bound polyphenols from pitahaya (Hylocereus undatus 'Foo-Lon') peel: Composition,antioxidant activities and enzyme inhibitory activity

In this study, ultrasound-assisted alkaline hydrolysis was used to extract polyphenols from pitahaya peel. The effects of sonication time, ultrasonic density, NaOH concentration and the liquid–material ratio on the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of the extracts were studied. The composition and content difference of the extracts were analyzed and the inhibitory effect of α-amylase and α-glucosidase was measured. The results of single-factor analysis showed that when the sonication time was 45 min, the ultrasonic density was 32 W/L, the NaOH solution concentration was 6 M and the liquid–material ratio was 30 mL/g, the release of phenolic compounds was the largest and the antioxidant activity was the strongest. An UPLC-QTOF-MS/MS method was used to analyze the components and contents of the extracts. We found that there was a great difference in the component content of the free polyphenol extract and the bound polyphenol extract. From the results, we concluded that there was a strong correlation between the type and content of phenolic compounds and antioxidant activities, indicating that phenolic compounds were the main compounds of these biological activities. Moreover, the bound polyphenol extracts showed a significant inhibitory effect on α-amylase and α-glucosidase was stronger than that of the free polyphenol extracts. In addition, scanning electron microscopy showed that ultrasound-assisted extraction is crucial to the destruction of the cell wall and the release of bound polyphenols. Therefore, the pitahaya peel has the potential for therapeutic, nutritional, and functional food applications, and ultrasound-assisted alkaline hydrolysis is an effective means to release phenolic compounds.     

Effects of ultrasound pretreatment on functional property,antioxidant activity,and digestibility of soy protein isolate nanofibrils

Nanofibrils, an effective method to modulate the functional properties of proteins, can be promoted by ultrasound pretreatment. This study investigated the effect of ultrasound pretreatment on the structure, functional property, antioxidant activity and digestibility of soy protein isolate (SPI) nanofibrils. The results showed that high amplitude ultrasound had a significant effect on structure of SPI nanofibrils. SPI nanofibrils pretreated by 80% amplitude ultrasound showed a blueshift of the amide II band in Fourier transform infrared spectroscopy (FTIR), resulted in more tryptophan residues being buried and increased the crystallinity. Low amplitude ultrasound (20%) pretreatment significantly improved the solubility, emulsifying activity index (EAI) and water absorption capacity (WAC) of SPI nanofibrils, but 80% amplitude ultrasound pretreatment of SPI nanofibrils reduced emulsifying stability index (ESI). High amplitude ultrasound (60% and 80%) pretreatment of SPI nanofibrils improved the foaming capacity and foaming stability and decreased denaturation temperature. DPPH radical scavenging activity of SPI nanofibrils were significantly improved by ultrasound pretreatment. 20% amplitude ultrasound pretreatment improved DPPH, ABTS radical scavenging activity and ferric reducing antioxidant power of SPI nanofibrils. The digestion rate of 80% amplitude ultrasound-pretreated nanofibrils were consistently higher, and SPI nanofibrils pretreated by ultrasound were more fragmented and shorter after simulating gastrointestinal digestion. This study would expand the application of food-grade protein nanofibrils in the food industry.     

Study of continuous flow ultrasonication to improve total phenolic content and antioxidant activity in sorghum flour and its comparison with batch ultrasonication

Ultrasonic technology was applied to release the phenolics bound with starch and protein matrix in order to enhance total phenolic content (TPC) and antioxidant activity (AA) of the sorghum flour. Both the continuous flow and batch ultrasonication were implied with independent variables such as flour to water ratio (FWR), ultrasonication intensity (UI), and ultrasonication time (UT) with an additional variable as flow rate (FR) in continuous flow ultrasonication. All the process variables showed a significant effect on the corresponding ultrasonication process. The optimal conditions for the continuous flow ultrasonication were a FWR of 10% w/v, an UI of 20 W/cm², an UT of 130 s, and 15 ml/s FR which produced a maximum values of 70.9 mg GAE/100 g dry matter (d.m.) for TPC and 143.9 µmol TE/100 g d.m. for AA. Regarding the batch ultrasonication, the maximum values were 65.6 mg GAE/100 g d.m. and 141.0 µmol TE/100 g d.m. for TPC and AA, respectively at optimum conditions of 10% w/v FWR, 30 W/cm² UI, and 200 s UT. When comparing with the batch ultrasonication, the continuous flow process saved 35% time and 33% of energy consumption to obtain comparatively higher TPC and AA of the sorghum flour. Ultrasonication improved free phenolic acid content by releasing bound phenolics in the sorghum flour. Impact of various process parameters on specific energy was analyzed during both the processes, and influence of energy on TPC and AA of the sorghum flour was also observed for the batch and continuous flow ultrasonication.     

Ultrasonic effects on the degradation kinetics,preliminary characterization and antioxidant activities of polysaccharides from Phellinus linteus mycelia

In this study, a high-molecular-weight polysaccharide PL-N isolated from the alkaline extract of Phellinus linteus mycelia was degraded by ultrasound. Results showed that ultrasound treatment at different ultrasonic intensities decreased the intrinsic viscosity and molecular weight of PL-N, as well as narrowed the molecular weight distribution. A larger reduction in intrinsic viscosity and molecular weight was caused by a higher ultrasonic intensity. The degradation kinetics model was fitted to (1/M_t − 1/M₀) = k·t, and the reaction rate constant (k) increased with increasing ultrasonic intensity. Ultrasound degradation did not change the primary structure of PL-N, and scanning electron microscopy analysis indicated that the morphology of the original PL-N was different from that of degraded PL-N fractions. Antioxidant activity assays in vitro indicated that the degraded PL-N fraction with low molecular weight had stronger hydroxyl radical scavenging capacity and higher TEAC and FRAP values.     

Analysis in protein profile,antioxidant activity and structure-activity relationship based on ultrasound-assisted liquid-state fermentation of soybean meal with Bacillus subtilis

This study investigated effects of ultrasound on the contents of peptide and soluble protein, antioxidant activity, functionalities and structural characteristics of fermented soybean meal (FSBM) with Bacillus subtilis systematically. The results showed that there were significant effects of ultrasound treatments (frequency, treatment time and power density) on the contents of peptide and soluble protein (p < 0.05). Under the optimum ultrasound conditions (power density of 0.08 W/mL, frequency of 33 kHz and treatment time of 1 h) by single factor experiment, the contents of peptide and soluble protein increased by 31.27% and 18.79% compared to those of the control, respectively. Additionally, the in vitro antioxidant activity (•OH scavenging rate, Fe²⁺ chelating capacity and DPPH radical scavenging rate) and functional properties (emulsifying activity and emulsifying stability) of FSBM were found to be noticeably improved by ultrasound (p < 0.05). The fourier transform infrared (FTIR) spectroscopy revealed that ultrasound caused protein molecules to unfold with a decrease content of α-helix and β-turn and an increase in the proportion of β-sheet and random coil. Besides, atomic force microscope (AFM) results indicated that ultrasonication generally increased the surface roughness of protein and the protein sonicated with higher frequency (≥33 kHz) exhibited a greater height compared to lower frequency ultrasonication. Structure-activity relationship analysis illustrated that there was a good linear relationship between •OH scavenging rate and β-sheet/β-turn with Pearson’s correlation coefficient r of −0.86/0.90. Collectively, the selection of ultrasonic parameters is essential for the preparation of functional protein and bioactive peptide by enhancing fermentation of agroindustrial by-products.     

Effects of ultrasound-assisted heating on aroma profile,peptide structure,peptide molecular weight,antioxidant activities and sensory characteristics of natural fish flavouring

This study deals with the production of natural fish flavouring using ultrasound-assisted heating process. The effect of ultrasound pretreatment at different amplitudes (0, 15, 30, and 45%) on the Maillard reaction rate, antioxidant activities, flavour profile, and sensory characteristics of fish flavouring was investigated. Results showed that sonication markedly accelerated the Maillard reaction (MR) rate, as evidenced by the modification of peptide structure, a decrease in pH value, free amino acid content coupled with a rise in browning intensity. Also, ultrasound pretreatment significantly enhanced the antioxidant activities of fish flavouring (p ≤ 0.05). Moreover, sonication increased the type and content of aroma compounds significantly. Sensory analysis revealed that ultrasound pretreatment increased the fish-like and toasty aroma as well as umami and mouthfulness attributes coupled with the reduction of the bitter taste of the fish flavouring. This result was consistent with the GC–MS, electronic nose, cluster, and Partial Least Squares Regression (PLSR) analyses, which clearly showed that ultrasound pretreatment enhanced the fish-like aroma, which was associated with the increase in aldehydes, ketones, alcohols, thiophenes, pyrazine, and furans contents. Thus, it could be concluded that ultrasound pretreatment, coupled with the thermal process, could be a promising process for the production of natural fish flavouring with higher antioxidant activities.     

Modification in structural,physicochemical, functional,and in vitro digestive properties of kiwi starch by high-power ultrasound treatment

Kiwi starch (KS) is a fruit-derived starch; in order to improve its processing performance and increase its added value, it is necessary to modify KS to enhance the positive attributes and to enlarge its application. In this study, KS was modified by high-power ultrasound treatment (HUT) to reveal the relationship between the structure and function of KS with different treatment powers (0, 200, 400, and 600 W) and different treatment times (0, 10, 20, and 30 min). The results showed that HUT destroyed the granular morphology of KS, formed holes and cracks on the surface, and reduced the particle size and the short-range molecular order of KS. After different HUTs, the apparent amylose content (AAC), swelling power (SP), water solubility index (WSI), viscosity and setback value (SB) of KS were significantly increased, while the gelatinization temperature was significantly decreased. In addition, HUT significantly reduced the content of rapidly digestible starch (RDS) and slowly digestible starch (SDS), while it significantly enhanced the content of resistant starch (RS) (64.08–72.73%). In a word, HUT as a novel physical modification method for KS, enlarged its application, and fulfilled different demands of a starch-based product, which introduces another possibility for kiwi fruit further processing.     

Combined effect of ultrasound,heat, and pressure on Escherichia coli O157:H7, polyphenol oxidase activity,and anthocyanins in blueberry (Vaccinium corymbosum) juice

The objective of this study was to evaluate the effect of different treatments—heat treatment (HT), sonication (SC), thermosonication (TS), manosonication (MS), manothermal (MT), and manothermosonication (MTS) on Escherichia coli O157:H7, polyphenol oxidase (PPO), and anthocyanin content in blueberry juice. First, samples were treated at different temperatures (30, 40, 50, 60, 70, and 80 °C) and power intensities (280, 420, 560, and 700 W) for 10 min. Subsequently, samples were treated using combinations of power intensity and mild temperature for 10 min. For further study, samples were treated using HT (80 °C), TS (40 °C, 560 W), MT (350 MPa, 40 °C), MS (560 W, 5 min/350 MPa), or MTS (560 W, 5 min, 40 °C/350 MPa, 40 °C) for 5, 10, 15, 20 min for each treatment, and the results compared between treatments. HT significantly reduced PPO activation (2.05% residual activity after only 5 min), and resulted in a 2.00-log reduction in E. coli O157:H7 and an 85.25% retention of anthocyanin. Escherichia coli O157:H7 was slightly inactivated by TS after 5 min (0.17-log reduction), while residual PPO activity was 23.36% and anthocyanin retention was 98.48%. However, Escherichia coli O157:H7 was rapidly inactivated by MTS (5.85-log reduction) after 5 min, while anthocyanin retention was 97.49% and residual PPO activity dropped to 10.91%. The destruction of E. coli cells as a result of these treatments were confirmed using SEM and TEM. Therefore, a combination of sonication, high pressure, and mild heat allows the safety of blueberry juice to be maintained without compromising the retention of desirable antioxidant compounds.     

Thermosonication effect on bioactive compounds,enzymes activity,particle size,microbial load,and sensory properties of almond (Prunus dulcis) milk

The object of this research was to appraise the physicochemical characteristics of almond milk and consumer acceptability after the thermosonication (TS) processing. The almond milk was subjected to TS processing (frequency: 40 kHz; power: 600 W; Temperature: 30, 45, and 60 °C; Time: 10, 20, 30, and 40 min) and pasteurization (for 60 s at 90 °C). After treatments, all samples were analyzed for bioactive compounds, antioxidant activities, microbial, enzymatic, and sensory attributes. The results showed a non-significant difference in total soluble solids and pH while TS processing at 45 and 60 °C significantly increased the cloudiness, viscosity, browning index, and color properties. TS processing increased the bioavailability of total phenolic, flavonols, flavonoids, condensed tannin contents, and antioxidant activity as compared to untreated and pasteurized samples. TS processing also significantly reduced the particle size distribution through acoustic cavitation. Microbial inactivation with TS at 60 °C resulted in ≥ 5 log reduction of total plate count and ≥ 4 log reduction of yeast & mold was achieved. The highest inhibition of lipoxygenase (LOX) and peroxidase (POD) were observed at 60 °C for 30 min. Moreover, the best sensorial properties were observed after TS processing at 60 °C. Thus; TS processing can increase the almond milk quality and safety as a viable substitute for thermal processing.     

Symbiosis between in vivo and in vitro NMR spectroscopy: The creatine, N-acetylaspartate, glutamate, and GABA content of the epileptic human brain

High resolution ¹H NMR spectroscopy was used to analyze temporal lobe biopsies obtained from patients with epilepsy. Heat-stabilized cerebrum, dialyzed cytosolic macromolecules, and perchloric acid extracts were studied using one- and two dimensional spectroscopy. Anterior temporal lobe neocortex was enriched in GABA, glutamate, alanine, N-acetylaspartate, and creatine. Subjacent white matter was enriched in aspartate, glutamine, and inositol. The N-acetylaspartate/creatine mole ratio was lower in anterior temporal neocortex with mesial (0.66) than neocortical (0.80) temporal lobe epilepsy. Human brain biopsy samples were separated into crude and refined synaptosomes, neuronal cell bodies, and glia using density gradient centrifugation. Neuronal fractions were enriched in glutamate and N-acetylaspartate. Glial cell fractions were enriched in lactate, glutamine, and inositol. The creatine content was the same in biopsied epileptic cortex (8.8–8.9 mmol/kg) and normal in vivo occipital lobe (8.9 mmol/kg). Glutamate content was higher in epileptic cortex at biopsy (10.1–10.5 mmol/kg) than normal in vivo occipital lobe (8.8 mmol/kg). GABA content was higher in biopsies of epileptic cortex (2.3–2.2 mmol/kg) than in normal in vivo occipital lobe (1.2 mmol/kg). N-acetylaspartate content was lower in biopsied epileptic temporal cortex (5.8–6.8 mmol/kg) than normal in vivo occipital lobe (8.9 mmol/kg). Paired in vivo and ex vivo measurements are critical for a firm understanding of the changes seen in the ¹H-spectra from patients with epilepsy.     

Dietary lipid content influences the activity of lipogenic enzymes in the liver and on whole body delta13C values of Nile tilapia, Oreochromis niloticus (L.)

The use of stable isotope techniques for the reconstruction of diets has increased over the last decade. However, isotopic ratios in an animal are not only affected by the composition of the feed, but also by the amount of feed consumed. An uncertainty of up to 1 per thousand for both delta13C and delta15N values has been observed when the feeding level is unknown. This may have substantial effects on the results of back-calculation. As the feeding level of animals is unknown in nature, an additional indicator for their nutritional status is needed. High feeding levels and a consequent surfeit of dietary energy lead to the synthesis of lipids. In order to test whether the level of lipogenesis could be used as an indicator, Nile tilapia (Oreochromis niloticus) were fed four isonitrogenous and isoenergetic wheat-based semi-synthetic diets with different lipid contents (2.0 %, 4.5 %, 9.5 % and 13.3 %) for eight weeks. Body composition, gross energy content and delta13C values in the lipids and the lipid-free material were determined in diets and fish bodies. The livers of three fish per feeding group were assayed for the activity of two lipogenic enzymes, ATP-citrate lyase and malic enzyme. There was a strong negative correlation between delta13C values in the lipids of the individual fish and the apparent lipid conversion. The activities of lipogenic enzymes decreased with rising lipid content in the diet. The delta13C values in the lipids decreased significantly with increasing specific activity for both enzymes. In this experiment where lipogenesis was influenced by the composition of the diet, it was possible to determine the exact value for the trophic shift in relation to the enzyme activities. Further experiments to investigate the use of enzyme activities in situations where the feeding level of an animal is unknown are recommended.     

Ultrasound processing to enhance drying of cashew apple bagasse puree: Influence on antioxidant properties and in vitro bioaccessibility of bioactive compounds

The present study has evaluated the effects of power ultrasound pre-treatment on air-drying and bioactive compounds of cashew apple bagasse. The sonication induced the disruption of cashew bagasse parenchyma, which resulted in lower resistance to water diffusion, less hysteresis, and increased rehydration rate. The processing did not affect the lignocellulose fibers or the sclerenchyma cells. For sonicated samples, water activity reached values below 0.4, after 2 h of drying, which is appropriate to prevent bacterial and fungi growth. The sorption isotherms of cashew apple bagasse presented sigmoid-shape for all samples and followed the type II according to BET classification. Sonicated cashew apple bagasse showed higher antioxidant activity, higher total phenolic compounds (TPC) and higher vitamin C content when compared to the non-sonicated sample. The increase in TPC and vitamin C contributed to the product antioxidant activity. A slight reduction on Vitamin C bioaccessibility was observed, but the TPC bioaccessibility has increased. Sonication reduced the quality loss of conventional drying treatments improving the quality of the dried product.     

First-principles calculations of the effect of Ge content on the electronic,mechanical and acoustic properties of Li17Si4-xGex

The electronic, mechanical and acoustic properties of Li₁₇Si_4-xGe_x (x = 0, 2.3, 3.08, 3.53, and 4) have been investigated by using first-principles calculations based on the density functional theory (DFT). The research shows that the bulk modulus B, Young's modulus E, shear modulus G, and hardness H_v gradually decrease with the increasing Ge content. Li₁₇Si_4-xGe_x have the brittle nature from the analysis of B/G ratio and Cauchy pressure. The maximum Young's moduli are all along [1 1 0] plane, and the sequence of degree of anisotropic property is Li₁₇Ge₄ > Li₁₇Si_0.48Ge_3.52 > Li₁₇Si_0.92Ge_3.08 > Li₁₇Si_1.7Ge_2.3 > Li₁₇Si₄. The analysis of acoustic velocity shows that all the sound velocities decrease with the increasing Ge content for Li₁₇Si_4-xGe_x (x = 0, 2.3, 3.08, 3.53, and 4), and the longitudinal wave along [111] direction is fastest for the studied compounds. Debye temperature Θ_D, v_t and v_l decrease with the increasing Ge content. The minimum thermal conductivity decreases with the increasing Ge content, and Li₁₇Si_4-xGe_x have low thermal conductivities and are not potential thermal conductors. The analysis of electronic properties indicates that Li₁₇Si_4-xGe_x have the metal nature and anisotropic electrical conductivity. The electric conduction is improved with the increasing Ge content.     

Ultrasonic-assisted micro solid phase extraction of arsenic on a new ion-imprinted polymer synthesized from chitosan-stabilized pickering emulsion in water,rice and vegetable samples

Pickering emulsion polymerization has been employed for the Ultrasonic assisted-micro solid phase extraction (UA-µSPE) of ultra trace arsenic species by a new magnetic ion imprinted polymer (MIIP) prior to hydride generation atomic absorption spectrometry. 2-acetyl benzofuran thiosemicarbazone (2-ABT) as a new chelating agent and core- shell hydrophobic magnetic nanoparticles was synthesized and the polymerization was carried out at the presence of arsenic – ligand complex, crosslinker, monomer, initiator, stabilizing agent and water-oil emulsion magnetic carrier. In second step, the nanoparticles and polymers were characterized. The analytical parameters such as pH, amount of polymer and ultrasonic time were selected and optimozed by Plackett–Burman and Box–Behnken designs respectively. Linear dynamic range, detection limit and relative standard deviation were 0.01–85.000 µg·L^−l, 0.003 µg·L^−l, and 3.21%, respectively. The proposed preconcentration procedure was successfully applied to the determination of arsenic ion in a wide range of food samples with different and complex matrixes.     

The effect of hydrostatic pressure,temperature and magnetic field on the nonlinear optical properties of asymmetrical Gaussian potential quantum wells

In this study, simultaneous effects of hydrostatic pressure, temperature and magnetic field on the linear and nonlinear intersubband optical absorption coefficients (OACs) and refractive index changes (RICs) in asymmetrical Gaussian potential quantum wells (QWs) are theoretically investigated within the framework of the compact-density-matrix approach and iterative method. The energy eigenvalues and their corresponding eigenfunctions of the system are calculated with the differential method. Our results show that the position and the magnitude of the resonant peaks of the nonlinear OACs and RICs depend strongly on the hydrostatic pressure, temperature and external magnetic field. This gives a new degree of freedom in various device applications based on the intersubband transitions of electrons.