Sonication Intensity Research Articles

Sonication-facilitated immunofluorescence staining of late-stage embryonic and larval Drosophila tissues in situ.

Studies performed in Drosophila melanogaster embryos and larvae provide crucial insight into developmental processes such as cell fate specification and organogenesis. Immunostaining allows for the visualization of developing tissues and organs. However, a protective cuticle that forms at the end of embryogenesis prevents permeation of antibodies into late-stage embryos and larvae. While dissection prior to immunostaining is regularly used to analyze Drosophila larval tissues, it proves inefficient for some analyses because small tissues may be difficult to locate and isolate. Sonication provides an alternative to dissection in larval Drosophila immunostaining protocols. It allows for quick, simultaneous processing of large numbers of late-stage embryos and larvae and maintains in situ morphology. After fixation in formaldehyde, a sample is sonicated. Sample is then subjected to immunostaining with antigen-specific primary antibodies and fluorescently labeled secondary antibodies to visualize target cell types and specific proteins via fluorescence microscopy. During the process of sonication, proper placement of a sonicating probe above the sample, as well as the duration and intensity of sonication, is critical. Additonal minor modifications to standard immunostaining protocols may be required for high quality stains. For antibodies with low signal to noise ratio, longer incubation times are typically necessary. As a proof of concept for this sonication-facilitated protocol, we show immunostains of three tissue types (testes, ovaries, and neural tissues) at a range of developmental stages.

Sonication-facilitated Immunofluorescence Staining of Late-stage Embryonic and Larval <em>Drosophila</em> Tissues <em>In Situ</em>

Studies performed in Drosophila melanogaster embryos and larvae provide crucial insight into developmental processes such as cell fate specification and organogenesis. Immunostaining allows for the visualization of developing tissues and organs. However, a protective cuticle that forms at the end of embryogenesis prevents permeation of antibodies into late-stage embryos and larvae. While dissection prior to immunostaining is regularly used to analyze Drosophila larval tissues, it proves inefficient for some analyses because small tissues may be difficult to locate and isolate. Sonication provides an alternative to dissection in larval Drosophila immunostaining protocols. It allows for quick, simultaneous processing of large numbers of late-stage embryos and larvae and maintains in situ morphology. After fixation in formaldehyde, a sample is sonicated. Sample is then subjected to immunostaining with antigen-specific primary antibodies and fluorescently labeled secondary antibodies to visualize target cell types and specific proteins via fluorescence microscopy. During the process of sonication, proper placement of a sonicating probe above the sample, as well as the duration and intensity of sonication, is critical. Additonal minor modifications to standard immunostaining protocols may be required for high quality stains. For antibodies with low signal to noise ratio, longer incubation times are typically necessary. As a proof of concept for this sonication-facilitated protocol, we show immunostains of three tissue types (testes, ovaries, and neural tissues) at a range of developmental stages.

Thin Layer Sonoelectrochemistry

Ultrasound irradiation of electrodes in a thin electrolyte layer improves heterogeneous electron transfer kinetics.1,2 A bulk fluid irradiated with ultrasonic energy of sufficient intensity generates bubbles by compression and rarefaction. On bubble collapse, extremes of temperature (T ≳ 5000 K) and pressure (P ≳ 10³ atm) are generated at the narrow interface between the fluid and bubble void3. In bulk fluids, ultrasound enhances transport and impacts homogeneous reactions, but the energy attenuates. In prior sonoelectrochemical studies (first by Coury), bulk electrolyte was irradiated with sufficient ultrasonic intensity to generate cavitation. Cavitation increased homogeneous reaction rates, transport, and turbulence. No effects on heterogeneous electron transfer were found. In a thin layer sonoelectrochemical system (Figure 1), heterogeneous electron transfer rates increase. Thin layers have two advantages for harvesting sound energy2. Sound waves reflect back into the thin layer | air interface to retain energy. Losses from attenuation are less within thin layers. No frank cavitation is observed in thin layers.Electrolyte fills the well to form a meniscus. Cyclic voltammograms are recorded for each Ru(bpy)3 2+ and Fe3+ with and without sonication (Figure 2). Sonication intensity can be varied. Sonication has no impact on the voltammetry for Ru(bpy)3 2+ for which electron transfer rates are rapid compared to the scan rate. Sonication does not impact transport. Rates of Fe3+ reduction increases with sonication intensity, as shown by the more rapid rise in current on sonication. Peak potentials shift because the reference is shifting. Where rates are slow, sonication increases heterogeneous electron transfer rates without significantly impact on diffusional transport1. References and Acknowledgments: Support of the National Science Foundation and the University of Iowa is gratefully acknowledged. With thanks to Andrej Wieckowski for his explorations and contributions to understanding electrocatalysis. [1] Chester G. Duda, Ph.D. dissertation, University of Iowa, 2012.[2] J. Leddy, C.G. Duda, and W.J. Leddy III, Provisional U.S. Patent application, 2013.[3] K.S. Suslick, Y. Didenko, M.M. Fang, T. Hyeon, K.J. Kolbeck, M.M. Mdleleni, and M. Wong, Acoustic Cavitation, Phil. Trans. Royal Soc. A 1999.

Purification, separation and extraction of inner tubes from double-walled carbon nanotubes by tailoring density gradient ultracentrifugation using optical probes

We studied the effect of varying sonication and centrifugation parameters on double-walled carbon nanotubes (DWCNT) by measuring optical absorption and photoluminescence (PL) of the samples. We found that by using a low sonication intensity before applying density gradient ultracentrifugation (DGU), only inner tube species with a diameter ⩽0.8nm can be identified in absorption measurements. This is in stark contrast to the result after sonicating at higher intensities, where also bigger inner tubes can be found. Furthermore, by comparing PL properties of samples centrifugated either with or without a gradient medium, we found that applying DGU greatly enhances the PL intensity, whereas centrifugation at even higher speeds but without a gradient medium results in lower intensities. This can be explained by extraction of inner tubes from their host outer tubes in a two-stage process: the different shearing forces from the sonication treatments result in some DWCNT to be opened, whereas others stay uncut. A subsequent application of DGU leads to the extraction of the inner tubes or not if the host nanotube stayed uncut or no gradient medium was used. This work shows a pathway to avoid this phenomenon to unravel the intrinsic PL from inner tubes of DWCNT.

Intensification in the Activity of Lipase Enzyme Using Ultrasonic Irradiation and Stability Studies

In the present work, the effect of ultrasound on the activity of lipase enzyme has been investigated using a probe-type sonicator capable of delivering variable power at a constant frequency of 20 kHz. It was observed that lipase enzyme gave a maximum activity at an ultrasound intensity of 12.22 W/cm2 and an optimized sonication time of 9 min and any further increase in the intensity and time of sonication resulted in a decrease in activity. The maximum increase in the activity of the enzyme was 2-fold. All of the operating parameters were also optimized by the response surface methodology (RSM) approach. Immobilization of the enzyme was achieved after sonication at the optimized parameters to retain the activity of the enzyme, which gave 47.9% retention of the activity in the tributyrin hydrolysis reaction. Using the same reaction, the intensification phenomenon of the immobilized enzyme was also supported by thermodynamic studies, which showed considerable decreases in ΔG, ΔS, ΔH, and ΔE with sonicated ...

Enhanced Aeromonas salmonicida bacterin uptake and side effects caused by low frequency sonophoresis in rainbow trout (Oncorhynchus mykiss)

Low frequency sonophoresis (LFS) has been recognized as one of the most advanced technologies in transdermal delivery of substances, due to the modification of the stratum corneum lipid bilayer, in focal skin applications in mammals. Based on these findings, LFS has been suggested as a potential technology to be used for enhancement in immersion fish vaccination. In contrast to mammals where LFS is applied to discrete regions of the skin, in fish the whole individual needs to be exposed for practical purposes. The current study evaluated the impact of LFS at 37 kHz on the uptake of an Aeromonas salmonicida bacterin and side effects of the treatment in rainbow trout. Quantitative real time PCR (qPCR) and immunohistochemistry were used to examine the bacterin uptake into skin and gill tissue. Side effects were assessed by behavioural examination, histology and blood serum analysis. The sonication intensity of 171 mW/cm2 was enough for increasing skin permeability, but caused heavy erratic swimming and gill haemorrhages. Sonication intensities as low as 105 mW/cm2 did not modify skin permeability and enhanced the bacterin uptake into the gill tissue by factor 15 compared to conventional immersion. Following sonication, the gill permeability for the bacterin decreased after 20 min and 120 min by factor 3 and 2, respectively. However, during sonication, erratic swimming of the fish raised some concerns. Further reduction of the sonication intensity to 57 mW/cm2 did not induce erratic swimming, and the bacterin uptake into the gill tissue was still increased by factor 3. In addition, a decreasing albumin–globulin ratio in the serum of the rainbow trout within 40 min revealed that LFS leads to an inflammatory response. Consequently, based on both increased bacterin uptake and the inflammatory response, low intensity LFS has the potential to enhance vaccine immunity without significant side effects.

Effects of ultrasonic irradiation and direct heating on extraction of priority pesticides from marine sediments

Priority pesticides (alachlor, aldrin, γ-chlordane, chlorfenvinphos, chlorpyrifos, dieldrin, 4,4′-DDT, 4,4′-DDD, 4,4′-DDE, α-endosulfan, β-endosulfan, endosulfan sulphate, endrin, α-HCH, β-HCH, γ-HCH, δ-HCH, HCB, HCBD, heptachlor, heptachlor epoxide, isodrin, methoxychlor, mirex, quintozene, terbuthylazine and trifluralin) are a group of toxic substances that are known by their persistency in the aquatic environment. Their screening in marine sediments may provide information on the sources and distribution in the water mass of fresh-transitional and coastal waters. This work proposes a rapid and reliable method to extract multi-residues of priority pesticides by ultrasounds irradiation from marine sediments. Multiple variables have been optimised: ultrasound frequency, sonication intensity, signal operation mode, time of extraction and water bath temperature. After sample clean-up and pre-concentration of the pesticides by stir bar sorptive extraction, the compounds were analysed by gas chromatography-mass spectrometry (GC-MS) using the selective ion monitoring acquisition mode (SIM). Better performance was found for ultrasonic-assisted extractions (UAE) at frequency of 35 kHz and an output intensity of 60% in a sweep mode of operation. An increase of water bath temperature to 80°C had a significant effect on the extraction of pesticides with high octanol-water partitioning coefficients (Kow). Under optimal conditions, method detection limits (MDLs) and method quantification limits (MQLs) ranged from 0.3 to 4.4 ng g−1 and from 0.8 to 14 ng g−1, respectively. Recoveries between 70 and 111%, at high precision levels, were found at different types of marine sediments with a single extraction cycle. Method performance was in good agreement with quality control guidelines.

Study of mechanism of sonoporation using lipid bilayer and surface-modified microbubble

Microbubble enhanced sonoporation is one of gene therapies and expected to be safe, less invasive, and controllability of treatment area, but its induction rate is very low and its mechanism remains to be explained. The objective is to analyze the mechanism and obtain an optimal design. Because microbubble density distribution was unstable during sonication and ultrasound intensity on the cell surface was affected by distribution change through attenuation change during propagation, microbubble distribution should be controlled and localized only near the membrane to realize high reproducibility. An artificial lipid bilayer modified by biotin-avidin to bind microbubbles was used for this purpose. We have three steps: build lipid bilayer, binding with microbubbles, and introduction of sonication and observation system. We built the lipid bilayer with a diameter of 1 mm using Black Lipid Membrane method. With a capacitance measurement with impedance analyzer (NF, ZM2375), the lipid bilayer thickness was confirmed and its duration is more than an hour. Then, we introduced the sonication and observation system to the lipid bilayer, and we are observing a behavior of the lipid bilayer under irradiation of ultrasound. Afterward we will observe that of a lipid bilayer modified of microbubbles.

Manufacturing process improvement and mechanical modelling of multiwalled carbon nanotube/epoxy composites

Multiwalled carbon nanotube (MWNT) reinforced epoxy resin composites were fabricated and characterised. Several process variables were investigated using design of experiments. The MWNTs (0·5 wt-%) were dispersed in Epon 862 epoxy resin under various sonication conditions. Young’s modulus, energy to failure, glass transition temperature Tg and storage modulus E′ were assessed. The first three were selected in a design of experiment optimisation study. The results indicated that as the sonication intensity and the duration of sonication were increased, the material response of the MWNT/epoxy composite, specifically Young’s modulus, energy and Tg, was enhanced. The fracture surfaces of the composites were examined using scanning electron microscopy. Improved dispersion was observed in samples fabricated with increased sonication intensities. The Mori–Tanaka model was used to predict the mechanical properties of the MWNT/epoxy composites and was found to be in reasonable agreement with experimental data. Nonetheless, the experimental results yielded slightly inferior properties to those from the model prediction.

Mixed matrix membranes incorporated with size-reduced Cu-BTC for improved gas separation

Metal–organic frameworks (MOFs), with large surface area and selective gas adsorption capability, can be the promising additives in mixed matrix membranes (MMMs) for potential gas separation. In this study, mixed matrix membranes with dispersed Cu-BTC [Cu3(BTC)2] have been fabricated and employed for gas separation. The sonication treatment was adopted to reduce the crystal size of MOFs and improve their affinity to the polymer matrix. The crystal structure, surface area and gas adsorption properties of as-synthesized and sonication-treated Cu-BTC were measured and compared. The morphology of the derived mixed matrix membranes varied with sonication intensity and Cu-BTC particle size, and the elimination of interfacial voids indicated the improvement of the adhesion between Cu-BTC crystals and the polymer matrix. The permeation test revealed that the gas permeance and selectivity of membranes depend on the crystal size of Cu-BTC fillers. Incorporation of the sonicated Cu-BTC results in enhancing both gas permeability and selectivity of the derived mixed matrix membranes. The analysis of permeation and gas sorption results also indicates that MOFs improve both diffusivity and solubility of gas molecules thus enhancing the permeability and selectivity of the membrane.

Sonochemical functionalization of mesoporous carbon for uranium extraction from seawater

Extracting uranium from seawater is challenging due to its low concentration (3.3 ppb) and the myriad of competing ions. Mesoporous carbon materials provide a high surface area alternative to the traditional polymeric fiber braids developed for seawater extractions, specifically uranium extraction. In this work, sonochemical grafting of acrylonitrile onto the pores of soft-templated mesoporous carbons followed by its conversion to amidoxime functionalities was used to prepare an effective sorbent material with a high density of binding sites. Pore blockage, often observed for free radical polymerization, leads to poor adsorbent performance but can be easily overcome by the use of ultrasound during polymerization. Parameters such as surface area and surface pre-treatment, sonication intensity, solvent system, and monomer/initiator ratios were varied to optimize the polymerization and uranium adsorption capacity while not blocking the porosity, a significant hurdle in the utilization of functionalized porous materials. The results show that neither the surface oxidation with nitric acid nor CO2 activation alone is sufficient to cause significant improvement in grafting and uranium uptake. However, when coupled together, a greatly enhanced performance of the adsorbent materials was observed.

Lipase catalyzed ultrasonic synthesis of poly-4-hydroxybutyrate-co-6-hydroxyhexanoate

Four different lipases were compared for ultrasound-mediated synthesis of the biodegradable copolymer poly-4-hydroxybutyrate-co-6-hydroxyhexanoate. The copolymerization was carried out in chloroform. Of the enzymes tested, Novozym 435 exhibited the highest copolymerization rate, in fact the reaction rate was observed to increase with about 26-fold from 30 to 50°C (7.9×10−3Ms−1), sonic power intensity of 2.6×103Wm−2 and dissipated energy of 130.4Jml−1. Copolymerization rates with the Candida antarctica lipase A, Candida rugosa lipase, and Lecitase Ultra™ were lower at 2.4×10−4, 1.3×10−4 and 3.5×10−4Ms−1, respectively. The catalytic efficiency depended on the enzyme. The efficiency ranged from 4.15×10−3s−1M−1 for Novozym 435–1.48×10−3s−1M−1 for C. rugosa lipase. Depending on the enzyme and sonication intensity, the monomer conversion ranged from 8.2% to 48.5%. The sonication power, time and temperature were found to affect the rate of copolymerization. Increasing sonication power intensity from 1.9×103 to 4.5×103Wm−2 resulted in an increased in acoustic pressure (Pa) from 3.7×108 to 5.7×108Nm−2 almost 2.4–3.7 times greater than the acoustic pressure (1.5×108Nm−2) that is required to cause cavitation in water. A corresponding acoustic particle acceleration (a) of 9.6×103–1.5×104ms−2 was calculated i.e. approximately 984–1500 times greater than under the action of gravity.

IMPROVEMENT OF OXIDATIVE STABILITY OF RICE BRAN OIL EMULSION BY CONTROLLING DROPLET SIZE

ABSTRACT Well-planned emulsification studies are needed to improve oxidative stability of rice bran oil. Factors that affect the droplet size during emulsification of rice bran oil include the amount of rice bran oil content, types of emulsifiers, power intensity and duration of sonication. In this study, the emulsions were prepared at different oil concentrations (10, 15 and 20%), using different emulsifiers (Tween 80 and its mixtures with Span 80), and subsequently sonicated at different durations (5–50 min). Longer sonication time resulted in smaller-sized emulsion droplets. The emulsions with the mixture of Tween 80 and Span 80 formed smaller droplets and better oxidative stability than those with Tween 80 only. In conclusion, rice bran oil emulsion with smaller droplets improves oxidative stability. This study may be helpful for tailoring oxidative-stable emulsions with well-defined droplet size distribution. PRACTICAL APPLICATIONS Recently, food manufacturers have been interested in utilization of the polishing by-products such as rice bran. Rice bran oil contains well-balanced saturated and unsaturated fats and provides a good source of vitamin E, antioxidants, oryzanol and other micronutrients. However, food application of rice bran oil is limited because of lipid oxidation. One of the promising technologies is nanoemulsion fabrication, which is being applied to enhance the oral bioavailability and oxidative stability of the poorly water-soluble bran oils. Herein, attention is focused on improving oxidative stability by controlling droplet size through adding mixture of surfactants in the oil-in-water emulsion. Narrow size distribution of droplets is a challenge for improved oxidative stability. In this study, proper formulations such as a mixture of emulsifiers provide a resolution to overcome the oxidative stability limitations in utilization of rice bran oils.

Separation of light and heavy organic matter fractions in soil — Testing for proper density cut-off and dispersion level

Density fractionation is frequently applied to separate soil organic matter according to the degree and the mode of interaction with minerals. Density fractions are operationally defined by density cut-off and sonication intensity, which determine the nature of the separated material. However, no tests or general agreements exist on the most appropriate density cut-off as well as on method and intensity of dispersion. Numerous variants have been proposed and applied, with results often contrasting each other and being hard to interpret. Here, we aimed at separating two light fractions (free and occluded into aggregates) composed of almost pure organic material, and one heavy fraction comprising the organic–mineral associations. We tested effects of different density cut-offs and sonication intensities, in combination and separately, on fraction yields, as well as on the fractions' organic carbon, total nitrogen and lignin-derived phenols. We tried to find optimum density cut-offs and sonication intensities, providing light fractions with maximum organic material and minimum contamination by mineral material. Under the test conditions, a density of 1.6gcm−3 gave best results for all test soils, allowing for separation of maximums amounts of almost pure organic material. The density cut-off at 1.6gcm−3 is well in line with previous studies and theoretical considerations, therefore we recommend the use of this density as most suitable for separation of organic debris. Sonication levels for aggregate disruption to achieve complete separation of occluded light organic matter varied amongst soils. The necessary intensity of dispersion relates to the type of soil, depending on the stability of contained aggregates. The application of one single dispersion energy level to different soils may result either in mineral contamination or in incomplete separation of light and heavy fractions as well as in redistribution of organic material amongst fractions. This means there is no single sonication level that can be applied to all soils. Thus, obtaining a meaningful light fraction residing within aggregates (occluded light fraction) requires assessment of the dispersion energy necessary to disrupt the aggregate system of a given soil without dispersion of organic–mineral associations. This can be done in pre-experiments where the soil is fractionated at different sonication levels. The appropriate dispersion is determined by mass yields and OC content of the obtained occluded fractions.

Effect of Mild Sonication Conditions on the Attributes of <i>Lactobacillus delbrueckii</i> ssp. <i>bulgaricus</i> LB-12

Lactobacillus delbrueckii ssp. bulgaricus is a widely used bacterium for the production of some fermented dairy products. Mild sonication intensity condition is a non-destructive technique that uses sound waves to cause cavitation in aqueous solutions and may improve the permeability of membranes, speed up the transfer of substrates and promote cellular growth and propagation. The objective was to determine the effect of mild sonication intensities at different temperatures on growth, bile tolerance and protease activity of Lactobacillus delbrueckii ssp. bulgaricus LB-12. The treatments were four sonication intensities (8.07, 14.68, 19.83 and 23.55 W/cm2) randomized at three different temperatures (4℃, 22℃ and 40℃). The energy input (1500 J) was kept constant in all treatments. Control samples did not receive any sonication treatment. Growth and bile tolerance were determined every 2 h for 12 h of incubation. Protease activity was determined at 0, 12 and 24 h. Mild sonication conditions included 1) mild sonication intensities, 2) temperatures and 3) times, all three of which played a role in influencing the desirable attributes of Lactobacillus delbrueckii ssp. bulgaricus LB-12. Of all the mild sonication intensities studied, 14.68 W/cm2 had the best overall influence at certain time points forimproving the bile tolerance and growth at 4℃ and protease activity at 40℃. Mild sonication intensity of 23.55 W/cm2 had the best overall influence at certain time points for protease activity of at 22℃. Some mild sonication conditions could be recommended for improvement of some characteristics of Lactobacillus delbrueckii ssp. bulgaricus LB-12.

Influence of “Mild” Sonication Conditions on the Characteristics of <i>Streptococcus thermophilus</i> ST-M5

Mild sonication intensity is an acoustic energy which involves the conversion of electrical signal into a physical vibration modifying the permeability of the cell plasma membrane. The objective of this study was to determine the effect of mild sonication intensities at different temperatures on growth, bile tolerance and protease activity of Streptococcus thermophilus. The treatments were four mild sonication intensities (8.07, 14.68, 19.83 and 23.55 W/cm2) randomized at three different temperatures (4°C, 22°C and 40°C). The energy input (1500 J) was kept constant in all treatments. Control samples did not receive any sonication treatment. Growth and bile tolerance were determined every two hours for 12 h of incubation. Protease activity was determined at 0, 12 and 24 h. Mild sonication conditions included a) mild sonication intensities, b) temperatures and c) times, all three of which played a role in influencing the desirable attributes of Streptococcus salivarius ssp. thermophilus ST-M5. Of all the mild sonication intensities studied, 14.68 W/cm2 had the best overall influence at certain time points for improving bile tolerance and growth at 4°C, growth at 22°C and bile tolerance and growth at 40°C of Streptococcus salivarius ssp. thermophilus ST-M5. Mild sonication intensity of 23.55 W/cm2 had the overall best influence at certain time points for protease activity of Streptococcus salivarius ssp. thermophilus ST-M5 at 40°C. Streptococcus thermophilus ST-M5 pretreatment with some mild sonication conditions can be recommended for improvement of some of its characteristics.

Cytotoxicity of Graphene Oxide and Graphene in Human Erythrocytes and Skin Fibroblasts

Two-dimensional carbon-based nanomaterials, including graphene oxide and graphene, are potential candidates for biomedical applications such as sensors, cell labeling, bacterial inhibition, and drug delivery. Herein, we explore the biocompatibility of graphene-related materials with controlled physical and chemical properties. The size and extent of exfoliation of graphene oxide sheets was varied by sonication intensity and time. Graphene sheets were obtained from graphene oxide by a simple (hydrazine-free) hydrothermal route. The particle size, morphology, exfoliation extent, oxygen content, and surface charge of graphene oxide and graphene were characterized by wide-angle powder X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, dynamic light scattering, and zeta-potential. One method of toxicity assessment was based on measurement of the efflux of hemoglobin from suspended red blood cells. At the smallest size, graphene oxide showed the greatest hemolytic activity, whereas aggregated graphene sheets exhibited the lowest hemolytic activity. Coating graphene oxide with chitosan nearly eliminated hemolytic activity. Together, these results demonstrate that particle size, particulate state, and oxygen content/surface charge of graphene have a strong impact on biological/toxicological responses to red blood cells. In addition, the cytotoxicity of graphene oxide and graphene sheets was investigated by measuring mitochondrial activity in adherent human skin fibroblasts using two assays. The methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay, a typical nanotoxicity assay, fails to predict the toxicity of graphene oxide and graphene toxicity because of the spontaneous reduction of MTT by graphene and graphene oxide, resulting in a false positive signal. However, appropriate alternate assessments, using the water-soluble tetrazolium salt (WST-8), trypan blue exclusion, and reactive oxygen species assay reveal that the compacted graphene sheets are more damaging to mammalian fibroblasts than the less densely packed graphene oxide. Clearly, the toxicity of graphene and graphene oxide depends on the exposure environment (i.e., whether or not aggregation occurs) and mode of interaction with cells (i.e., suspension versus adherent cell types).

Contribution of Oxides, Salt, and Carbonate to the Sonication of Some Hydrophobic Polyaromatic Hydrocarbons and Toxicity in Petrochemical Industry Wastewater in İzmir, Turkey

The effects of increasing sonication time (60–150 min), calcium chloride (CaCl2; 1–10 g/L), ferrous oxide (FeO; 2–10 mg/L), aluminium oxide (Al2O3; 2–10 mg/L), and Na2CO3 (2–12 mg/L) on the destruction of six polycyclic aromatic hydrocarbons (PAHs) and acute toxicity in a petrochemical industry wastewater in Izmir (Turkey) were investigated at a sonication intensity and a frequency of 51.48 W/cm2 and 35 kHz, respectively. The contribution of 4–6 mg/L CaCl2 to the yields in more hydrophobic PAHs [(benz[a]pyrene (BaP) and indeno[1,2,3-cd]pyrene (IcdP)] was low (6–8%), whereas it was high (21–26%) in less hydrophobic PAHs [acenaphthene (ACT), fluoranthene (FL), benz[a]anthracene (BaA), benz[k]fluoranthene (BkF)] at 30°C after 150 min sonication. 8 g/L Na2CO3 suppressed the removal of less hydrophobic PAHs (90–96%) although it did not contribute to the yields of more hydrophobic PAHs at 30°C after 150 min sonication. 6 g/L Al2O3 and 8 g/L FeO increased both less (E=93–95%) and more (E=90–94%) hydroph...

Effective dispersal of CNTs in the fabrication of electrodeposited nanocomposites

This study addresses the issue of carbon nanotube (CNT) agglomeration during the fabrication of electrodeposited metal–CNT coatings. A new means of assessing dispersion stability of CNTs within a Watts electrolyte via visible light spectrometry is outlined and used to demonstrate the extent of improved dispersibility of CNTs when subjected to a well-known surface modifying acid-treatment. Varying sonication was performed to control the dispersal state of CNTs within the electrolyte during electrodeposition using untreated and acid-treated CNTs. It was found that a Watts electrolyte containing acid-treated CNTs required significantly lower sonication intensity to maintain effective dispersal during electrodeposition, facilitating the fabrication of Ni–CNT coatings containing higher volume fractions of homogenously dispersed CNTs that exhibit superior mechanical properties.

기포군 영상분석을 통한 초음파 캐비테이션 현상의 변화 관찰

In this study, in order to evaluate the yield of bubble by ultrasonic cavitation in HIFU sonication, the bubble image analysis was performed. The changing phenomenon of cavitation effect according to the sonication condition was discussed by analyzing the bubble image. Especially the appearance of bubble cloud, the size of micro-bubble, and the yield of bubble were considered. The 500 KHz and 1.1 MHz concave type ultrasonic transducers were used for HIFU sonication. Computer controlled digital camera was used to obtain the bubble image, and the binary image processing(binarization coefficient : 0.15) was performed to analyze them. In results of 500 KHz and 1.1 MHz transducer, the area of bubble cloud was increased in proportion to the rise in sonication intensity(<TEX>$R^2$</TEX> : 0.7031 and 0.811). The mean size of single microbubble was measured as 98.18 um in 500 KHz sonication, and 63.38 um in 1.1 MHz sonication. In addition, the amount of produced bubble was increased in proportion to sonication intensity. Through the result of this study and further study for variable image processing method, the quantitative evaluation of ultrasonic cavitation effects in HIFU operation could be possible with the linearity associated with the sonication conditions.