Increasing Sonication Time Research Articles

Mechanism of light-dependent biosynthesis of silver nanoparticles mediated by cell extract of Neochloris oleoabundans.

This study investigated the role of chlorophyll and light in the biosynthesis of silver nanoparticles (AgNPs) using disrupted cell aqueous extract of Neochloris oleoabundans. It was found that, while increasing sonication time increased the percentage of disrupted cells and efficiency of aqueous cell extraction, over-sonication reduced AgNPs production. AgNPs biosynthesis required illumination of white, blue, or purple light while AgNPs formation was undetectable under dark condition or illumination of orange or red light, indicating only photons of high energy levels among the photosynthetic active radiations are capable of exciting the electrons of chlorophylls to a state that is sufficient for Ag+ reduction. Chlorophylls were demonstrated to be an essential component mediating the reduction of Ag+ and results of mass balance suggest that chlorophylls need to be recycled for the reaction to complete. The ultimate electron donor was hypothesized to be water, which supplemented electrons through water splitting catalyzed by photosynthetic enzyme complexes such as photosystem II. A hypothetical reaction mechanism is proposed for the light-dependent biosynthesis of AgNPs based on systematic experimental results and literature data for the first time.

Sonication-Induced Modification of Carbon Nanotubes: Effect on the Rheological and Thermo-Oxidative Behaviour of Polymer-Based Nanocomposites.

The aim of this work is the investigation of the effect of ultrasound treatment on the structural characteristics of carbon nanotubes (CNTs) and the consequent influence that the shortening induced by sonication exerts on the morphology, rheological behaviour and thermo-oxidative resistance of ultra-high molecular weight polyethylene (UHMWPE)-based nanocomposites. First, CNTs have been subjected to sonication for different time intervals and the performed spectroscopic and morphological analyses reveal that a dramatic decrease of the CNT’s original length occurs with increased sonication time. The reduction of the initial length of CNTs strongly affects the nanocomposite rheological behaviour, which progressively changes from solid-like to liquid-like as the CNT sonication time increases. The study of the thermo-oxidative behaviour of the investigated nanocomposites reveals that the CNT sonication has a detrimental effect on the thermo-oxidative stability of nanocomposites, especially for long exposure times. The worsening of the thermo-oxidative resistance of sonicated CNT-containing nanocomposites could be attributed to the lower thermal conductivity of low-aspect-ratio CNTs, which causes the increase of the local temperature at the polymer/nanofillers interphase, with the consequent acceleration of the degradative phenomena.

Controlled rupture of magnetic LbL polyelectrolyte capsules and subsequent release of contents employing high intensity focused ultrasound

Microcapsules consisting of 12 layers of poly(allylamine hydrochloride)/poly (styrene sulfonate) pairs were produced employing the Layer by Layer method with Fe3O4 super paramagnetic nanoparticles incorporated. BSA labelled RBITC was contained within the capsule core. Capsules implanted into a gel matrix were exposed to HIFU. Two sizes of samples were tested to see the range of focused ultrasound impact. Treatment conditions examined: ultrasonic intensities of 35W, 70W, 105W, irradiation periods of 1 s, 2 s, 4 s. Capsules with iron oxide in the 6th layer appear most stable in terms of capsule rupture, protein labelled dye release and iron leakage. Capsules with the iron oxide nanoparticles on the 4th or the 10th layer are easily ruptured allowing for protein labelled dye release with increased sonication time and increased applied ultrasonic power. This is thought to be due to the high levels of internal heat generated within capsules on sonication propagation. In the 4th and 10th layers an imbalance of heat dissipation is thought to occur resulting in enhanced capsule rupture. In the case of BSV samples these exhibited a greater amount of rupture than expected suggesting a wider impact of ultrasound suggesting a greater propagation through the tissue gel mimic.

Effect of ultrasound and chemical treatment on total phenol, flavonoids and antioxidant properties on carrot-grape juice blend during storage

Ultrasonics is one of the developing technologies which is being studied extensively on different food commodities. Our aim was to study the effect of sonication and chemical (Potassium metabisulfite, K2S2O5,) preservation method on grape-carrot juice blend. Sonication/ultrasound treatments (20 kHz frequency, 70% amplitude level (525 W power), and pulse duration 5 s on and 5 s off, 5 min at 15 °C) of all the samples (250 mL) were performed by using an ultrasonic processor with 0.5 in. probe at 2 in. depth of the sample. Additionally, impact of sonication on 90 days of storage period at refrigerated temperature was also measured. It was observed that sonication had a positive effect on nutritional status of juice blend as it enhanced the total phenolic, flavonoid, reducing power and antioxidant properties of juice significantly (p < 0.05) with increase in sonication time. Sonication can be employed successfully for treatment of juice with better nutritional attributes from consumers’ point of view.

Influence of probe-sonication process on drug entrapment efficiency of liposomes loaded with a hydrophobic drug

ABSTRACTSince probe-sonication is commonly used to homogenize liposomal formulations, it is necessary to investigate its influence on drug entrapment efficiency (EE) of liposomes. In this study, ibuprofen-loaded liposomes (IBU-Lip) dispersion was prepared from ibuprofen (IBU), soy phosphatidylcholine (SPC) and cholesterol (Chol) by thin film hydration and probe-sonication process. The influences of sonication time and power on EE were studied. Also, the effects of SPC-to-Chol ratio and drug-to-lipid ratio on EE were demonstrated. The results indicated that increasing sonication time or decreasing drug-to-lipid ratio could increase EE. Additionally, EE first increased then decreased as sonication power increased or SPC-to-Chol ratio decreased.

Rapid sonochemical synthesis of spherical silica nanoparticles derived from brown rice husk

The nanoparticles of silica (SiO2) were synthesized from brown rice husk via the sonochemical process, during which the sonication time was varied from 0 to 50 min so as to modulate the material properties of the nanoparticles. The synthesized SiO2 nanoparticles were confirmed to have amorphous natures in their structural characteristics. The mean particle sizes of the nanoparticles were increased from 5 to 40 nm with increasing sonication time from 0 to 50 min, respectively. The SiO2 nanoparticles synthesized with the sonication time of 50 min showed to possess the highest porosity among our samples. Accordingly, the sample exhibited a higher effective surface area of 271.22 m2g−1. In addition, the bandgap of the SiO2 nanoparticles was decreased from 5.77 to 5.68 eV with increasing sonication time (i.e., 0 → 50 min). The results suggest that the SiO2 nanoparticles synthesized with an appropriate control of the sonication time (e.g., 50 min) hold promise for future nano-ecosystem applications such as nano-biosensors and energy storage nano-devices.

Production and characterization of vitamin D3 loaded starch nanoparticles: effect of amylose to amylopectin ratio and sonication parameters.

Two types of starches with different amylose to amylopectin ratios were used for the production of vitamin D3 loaded nanoparticles and effects of starch type, sonication time and temperature on physicochemical properties of nanocarriers were investigated. Both high amylose corn and potato starches nanocarriers had granular structure with particle size ranging from 32.04 to 99.2nm and the encapsulation efficiency ranging from 22.34 to 94.8%. The results showed that potato starch nanoparticles had larger size, higher zeta potential, encapsulation efficiency and encapsulation load and lower polydispersity index values in comparison to high amylose corn starch nanoparticle. Increase in sonication time reduced the size of nanoparticles in both starch types and decreasing temperature led to reduction of particle size and increase of zeta potential. Physicochemical features of nanocarriers were analyzed by Fourier transform-infrared spectroscopy, X-ray diffraction and differential scanning calorimetry. The results indicated that vitamin D3 is well incorporated in carriers and ultrasonic treatment led to increase of hydrocarbon chain that resulted in van der Waals and hydrogen bonds of vitamin D3 with the potato starch and greater thermal stability.

Effects of sonication time and temperature on thermal conductivity of CuO/water and Al2O3/water nanofluids with and without surfactant

In this article, an experimental work was carried out to investigate the thermal conductivity of CuO/water and Al2O3/water nanofluids with and without surfactants. Three different volume concentrations of nanofluids (0.05, 0.1 and 0.2%) prepared by using single step preparation method. Sodium dodecylbenzene sulfonate used as a surfactant in this study. The analysis is carried out on the effects of sonication time and thermal conductivity of the prepared nanofluids by varying temperature from 30°C to 60°C. The obtained results indicate that the thermal conductivity of nanofluids increased with an increase of sonication time, temperature and the amount of surfactant. Also, the maximum thermal conductivity value was obtained for 0.2% volume concentration of CuO/water nanofluid with SDBS surfactant.

Influence of ultrasound on the electrical breakdown of transformer oil

When the transformer oil is exposed to low power ultrasonic waves (< 2 W/cm2) at initial moment the breakdown voltage of transformer oil is reduced relative to the breakdown voltage of pure oil due to degassing and the occurrence of cavitation bubbles. With the increase of sonication time the breakdown voltage also increases, nonlinearly. The experimental data indicate the possibility of using ultrasonic waves of low power for degassing of transformer oil.

Preparation and characterization of CNTs/UHMWPE nanocomposites via a novel mixer under synergy of ultrasonic wave and extensional deformation

In this work, design and development of a new melt mixing method and corresponding mixer for polymer materials were reported. Effects of ultrasonic power and sonication time on the carbon nanotubes (CNTs) filled ultra high molecular weight polyethylene (UHMWPE) nanocomposites were experimentally studied. Transmission Electron Microscopy images showed that homogeneous dispersion of CNTs in intractable UHMWPE matrix is successfully realized due to the synergetic effect of ultrasonic wave and extensional deformation without any aid of other additives or solvents. Differential scanning calorimetry results revealed an increase in crystallinity and crystallization rate due to the finer dispersion of the CNTs in the matrix which act as nucleating point. Composites’ complex viscosity and storage modulus decreased sharply at first and then leveled off with the increase of sonication time or the ultrasonic power. The thermal stability and the tensile strength of the CNTs/UHMWPE nanocomposites improved by using this novel mixing method. This is the first method that combined the ultrasonic wave and the extensional deformation in which the elongation rate, sonication time and ultrasonic power can be adjusted simultaneously during mixing. The novel mixer offers several advantages such as environment-friendly, high mixing efficiency, self-cleaning and wide adaptability to materials.

The effect of different frequencies of ultrasound on the activity of horseradish peroxidase

Ultrasound technology has been studied by food researchers as an alternative method for thermal processing. The use of ultrasound as a way to inactivate and/or activate enzymes has been widely studied at low frequencies (20–40 kHz), however, little research on the effect of high frequencies has been reported. Thus, the effect of high and low frequency ultrasound on commercial horseradish peroxidase with a concentration of 0.005 mg mL−1 is described. Experiments were performed for 60 min using 20, 378, 583, 862, 995, 1144 and 1175 kHz ultrasound at power levels (acoustic energy) between 2.1 and 64 W. Residual activity was monitored using a spectrophotometric method and data analysis was performed using ANOVA. A significant enhancement of enzyme inactivation (p < 0.05) was observed at each frequency with an increase of sonication time and power. Inactivation of peroxidase by ultrasound followed first order kinetics and an increase of the rate constant with the power applied was observed for all the frequencies studied. Overall, low frequency (20 kHz) and low power are not effective on the enzyme inactivation and the level of residual activity remained high. The use of 378 and 583 kHz (48 W) is particularly effective for complete enzyme inactivation.

Heating and megasonic interventions for improvement of aqueous-based oil extraction from fresh and cold stored coconut meat

The efficiency of oil recovery is essential for the economics of the coconut oil extraction process. This study evaluated the application of increased heat and/or megasonic steps for enhancing aqueous-based oil separation from coconut meat. Combinations of heating temperature (60 or 70 °C) and time (30 or 50 min) were studied in freshly prepared, or in 20 and 44 h cold stored (5 °C) coconut-water mixtures (1 L). The megasonic effect after heating (60 °C, 30 min) was evaluated at 2 MHz frequency and energy densities of 44–349 kJ/kg. Oil extraction from fresh coconut meat was higher when increasing heating temperature (10–13%). Net ultrasound yield in cold stored coconut meat was improved from 1.1 to 3.2% with increased sonication time from 2.5 to 20 min. Megasonic effects on mixtures heated (60 °C, 30 min) were corroborated in fresh coconut meat at a larger scale, which demonstrates the potential for megasonic to enhance aqueous-based coconut oil extraction processes.

Optimization of processing parameters for the development of Ficus religiosa L. extract loaded solid lipid nanoparticles using central composite design and evaluation of antidiabetic efficacy

The aim of the present work was to optimize processing parameters for the preparation of Ficus religiosa L. extract loaded solid lipid nanoparticles (SLN) using central composite design. Optimization was carried out using four factors such as homogenization speed, homogenization time, sonication time and sonication intensity and three responses studied were particle size, polydispersity index (PDI) and zeta potential to obtain a SLN batch with lesser particle size, optimum PDI and higher zeta potential. Further, optimized batch was characterized for entrapment efficiency, surface morphology, in-vitro release and kinetics, fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), powder Xray diffraction (PXRD) and stability over 6 months. From the results, it was observed that increase in homogenization speed and time decreased particle size and PDI with increase in zeta potential value. Increase in sonication time up to 5 min decreased particle size and further increase had no effect on particle size. Sonication intensity had very little effect. DSC and PXRD showed reduced crystallinity of extract in SLN form. Also, the optimized batch had stability over 6 months. Further, SLN significantly reduced diabetes induced higher levels of blood glucose and increased diabetes induced lower level of plasma insulin.

Formulation and Evaluation of Naringenin Nanosuspensions for Bioavailability Enhancement.

The clinical potential of naringenin (NRG) is compromised due to its poor aqueous solubility and low oral bioavailability. The study is aimed at addressing these issues by means of naringenin nanosuspensions (NRG-NS) formulated using polyvinylpyrrolidone (PVP K-90) as stabiliser via antisolvent sonoprecipitation method. Optimisation of sonication time, drug concentration and stabilisers was done based on particle size. Characterisation of pure NRG and NRG-NS was carried out by scanning electron microscopy, differential scanning calorimetry (DSC), x-ray powder diffractometry (XRD) and Fourier transform infrared spectroscopy (FTIR). In vitro dissolution, intestinal absorption by non-everted rat intestinal sac model and in situ single pass intestinal perfusion techniques were performed for further investigation. Nanosuspensions prepared using PVP K-90 lead to minimum particle size (117±5nm) with zeta potential of -14.6±5.6mV. The particle size was affected by increasing sonication time, concentration of stabiliser and drug. Nanosizing process converted the crystalline drug into amorphous form as predicted from DSC and XRD patterns. FTIR demonstrated the formation of hydrogen bonds between drug and polymer. NRG-NS displayed a higher dissolution amount (91±4.4% during 60min) compared to NRG powder (42±0.41%). The apparent and effective permeability of NRG-NS was increased as compared to the pure NRG. The in vivo pharmacokinetics demonstrated that the C max and AUC0-24h values of NRG-NS were approximately 2- and 1.8-fold superior than the pure drug. Hence, overall results confirmed nanosuspensions as promising approach for NRG delivery with high absorption in gastrointestinal tract, improved dissolution and oral bioavailability.

The effect of tin sulfide quantum dots size on photocatalytic and photovoltaic performance

In the current study, tin sulfide Quantum Dots (QDs) was successfully synthesized through sonochemical synthesis method by applying sonication times of 10, 15, and 20 min. Structural studies showed an orthorhombic phase of SnS and Sn2S3, and hexagonal phase of SnS2. The particle size of tin sulfide QDs prepared through sonication time of 20 min was smaller than other QDs. According to TEM images, an increase in sonication time resulted in smaller spherical shaped particles. According to the results of Raman studies, five Raman bands and a shift towards the lower frequencies were observed by enhancing the sonication time. Based on the outcomes of photocatalytic activity, higher this property was observed for tin sulfide QDs, which are prepared through longer sonication time. Solar cell devices manufactured using tin sulfide QDs have a greater performance for the samples with more sonication time. Considering the obtained outcomes, the sonication time seems probable to be a factor affecting synthesis process of SnS QDs as well as its optical and electrical, photocatalytic, and photovoltaic conversion features.

Improvement of nonlinear optical properties of graphene oxide in mixed with Ag2S@ZnS core-shells

Nonlinear optical properties including size and sign of nonlinear refractive index and nonlinear absorption coefficient of Graphene Oxide (GO), Ag2S@ZnS quantum dots and GO-Ag2S@ZnS were investigated using a Z-scan technique by laser diode with 532 nm wavelength. Third-order susceptibility of the compounds was calculated and compared with the reported values. By comparing the nonlinear optical (NLO) properties of GO and the mixture of GO-Ag2S@ZnS, it was observed that the NLO properties of GO were increased using simply mixing with Ag2S@ZnS quantum dots. It was also observed that with increase of sonication time, the NLO properties of the mixture increased accordingly.

Effect of the Controlled High-Intensity Ultrasound on Improving Functionality and Structural Changes of Egg White Proteins

The objective of this research was to investigate the impact of high-intensity ultrasound (HIU) generated by a probe-type sonicator (frequency 20 ± 0.2 kHz and an amplitude of 40%) for 2–20 min on the selected functional and structural properties of egg white proteins (EWPs) and their susceptibility to hydrolysis by alcalase. The protein solubility, foaming, and emulsifying properties were studied as a function of ultrasonication time and related to protein particle and structural properties. The length of ultrasonication exhibited important effect on EWP particle size, uniformity, and charge, affecting also the protein conformation and susceptibility to alcalase hydrolysis and determining functional properties. There was a linear correlation between the particle size decrease and the solubility while a two-step linear correlation between the foam capacity (FC)/foam stability (FS) and particle size was apparent. Specifically, FC and FS sharply increased with decreasing particle size for range from ∼370 to ∼260 nm, and below this range from 260.6 to 68.4 nm, the changes were not that substantial. Besides, the solubility, FC, and FS were directly and linearly related with the absolute value of the particle zeta potential. The overall emulsifying properties were also improved with an increase of sonication time, through both the decrease of the mean particle diameter and the increase of zeta potential, but there was no direct correlation between the emulsion activity/stability index and protein particle size and/or charge. Analysis of EWP structure by Raman spectroscopy revealed that the HIU leads to changes in the secondary structure, while heat and ultrasound generated by the ultrasound bath were not sufficient to exhibit this effect.

Fabrication of Freestanding Sheets of Multiwalled Carbon Nanotubes (Buckypapers) for Vanadium Redox Flow Batteries and Effects of Fabrication Variables on Electrochemical Performance

Typically, multiwalled carbon nanotubes (MWCNTs) are drop-casted on the surface of the underlying carbon substrates; the outcome is a randomly distributed MWCNT layers leading to uncontrollable structure and unreproducible results. Additionally, we suspect that the electrochemical response is influenced by the primary carbon-based substrate. Herein, we propose the use of freestanding sheets of MWCNTs (buckypapers, BP electrodes) as electrode materials for vanadium redox flow batteries to directly probe the electrochemical activity of MWCNTs toward VO2+/VO2+ and V2+/V3+ redox couples; henceforth, eliminating the need for an underlying carbon substrate. The amount of surfactant and the sonication time used during the fabrication of BP electrodes affect their morphological characteristics and electrochemical performances. Although the electrical conductivity of BP electrodes decreases with increasing surfactant amount and increasing sonication time, the heterogeneous rate constants for both redox couples increase as these fabrication variables are increased, indicating that the performance-limiting process is not electrical conductivity but the number of active sites available for the electrochemical reaction. The standard heterogeneous rate constant of the BP electrode with the highest amount of surfactant is comparable to those of state-of-the-art electrodes. Our promising results call for more research on the potential use of BP electrodes in redox flow batteries.

PVA Nanocomposites Reinforced with Cellulose Nanofibers from Oil Palm Empty Fruit Bunches (OPEFBs)

The objective of this study is to investigate the effect of sonication time on the morphology and properties of PVA cellulose nanocomposite. PVA nanocomposite films were prepared by reinforcement of cellulose nanofibers into a PVA matrix with different sonication time. Two series of poly(vinyl alcohol) (PVA) films with and without cellulose nanofibers were prepared by varying the sonication time. The effect of sonication time on the morphology and properties of the films were investigated by SEM, FTIR and Raman spectroscopy, TGA, and tensile test. The results showed that the mechanical property of the nanocomposite films increased with increasing sonication time until 9 min.

Synthesis and properties of polyacrylamide by nanoparticles, effect nanoclay on stability polyacrylamide solution

Polyacrylamide (PAM)-encapsulated clay nanoparticles (NPs) were successfully synthesised by conventional emulsion polymerisation for solving the aggregation matter of nanoscaled clay. A novel nanofluid based on PAM has been developed and its' attributes have been experimentally tested as an optimised solution. The frequency, sonication time effect, NPs and polymer concentration on the constant salinity and particle size (PS) distribution of samples was investigated. The solutions of polymer at different frequencies (10, 20 and 30 kHz) were treated with ultrasound for different times (5 and 15 min). The results showed that increasing sonication time decreased mean diameter of nanoclay mass and also showed with an increment range of frequency in specified range improved rheology and dispersion of the solution. Clay NPs were found to have a positive effect on the stability of samples.