High intensity focused ultrasound ablation of goat liver in vivo: Pathologic changes of portal vein and the “heat-sink” effect

The purpose of this study was to evaluate pathological changes of the portal vein (PV) and the effects on main branches of the hepatic PV during HIFU (high-intensity focused ultrasound) sonication when liver tissue adjacent to the main branches of hepatic PV was ablated. Normal liver tissue at 0 mm, 5 mm, 10 mm away from the hepatic portal vein in 50 healthy goats was ablated with magnetic resonance image-guided HIFU (MRgHIFU). MRI showed a non-perfusion region at the target area but did not show any significant changes of the PV immediately after HIFU. The histological examination 1 day after HIFU showed coagulative necrosis at the target area, revealed deep-dyed swelling collagen (CS) fibers and vessel wall fracture (VWF) in the PV adjacent to the target area; however, no CS or VWF was observed in the PV 1 week after HIFU ablation. The energy required to ablate the foci at 0 mm was 21% more than that at 10 mm from the PV (p < 0.05); the energy needed to ablate foci 5 mm away from the PV was 10% more than that at 10 mm from the PV (p < 0.05). We concluded that minor injury of the hepatic portal vein may occur when ablating the adjacent liver tissue, and the acoustic energy deposition is related to the distance to the portal vein.     

High-intensity focused ultrasound (HIFU) for adenomyosis: Two-year follow-up results

ObjectiveTo evaluate the long-term improvement of clinical symptoms of adenomyosis after treatment with ultrasound-guided high intensity focused ultrasound (USgHIFU).MethodsFrom January 2010 to December 2011, 350 patients with adenomyosis were treated with USgHIFU. Among the 350 patients, 224 of them completed the two years follow-up. The patients were followed up at 3 months, 1 year, and 2 years after HIFU treatment. Adverse effects and complications were recorded.ResultsAll patients completed HIFU ablation without severe postoperative complications. 203 of the 224 patients who showed varying degrees of dysmenorrhea before treatment had the symptom scores decreased significantly after treatment (P < 0.001). The relief rate was 84.7%, 84.7%, and 82.3%, respectively at 3 months, 1 year, and 2 years after treatment. The menstrual volume in 109 patients with menorrhagia was significantly improved after treatment (P < 0.001) with a relief rate of 79.8%, 80.7%, and 78.9%, respectively at 3 months, 1 year, and 2 years after HIFU treatment.ConclusionWith its ability to sustain long-term clinical improvements, HIFU is a safe and effective treatment for adenomyosis.     

Acute effects of sono-activated photocatalytic titanium dioxide nanoparticles on oral squamous cell carcinoma

Sonodynamic therapy (SDT) is a new treatment modality using ultrasound to activate certain chemical sensitizers for cancer therapy. In this study, effects of high intensity focused ultrasound (HIFU) combined with photocatalytic titanium dioxide (TiO₂) nanoparticles on human oral squamous cell line HSC-2 were investigated. Viability of HSC-2 cells after 0, 0.1, 1, or 3 s of HIFU irradiation with 20, 32, 55 and 73 W cm⁻² intensities in the presence or absence of TiO₂ was measured immediately after the exposures in vitro. Immediate effects of HIFU (3 s, 73 W cm⁻²) combined with TiO₂ on solid tumors were also examined by histological study. Cytotoxic effect of HIFU + TiO₂ in vitro was significantly higher than that of TiO₂ or HIFU alone with the tendency to increase for higher HIFU intensity, duration, and TiO₂ concentration in the suspension. In vivo results showed significant necrosis and tissue damage in HIFU and HIFU + TiO₂ treated samples. However, penetration of TiO₂ nanoparticles into the cell cytoplasm was only observed in HIFU + TiO₂ treated tissues. In this study, our findings provide a rational basis for the development of an effective HIFU based sonodynamic activation method. This approach offers an attractive non-invasive therapy technique for oral cancer in future.     

Safety of ultrasound-guided high-intensity focused ultrasound ablation for diffuse adenomyosis: A retrospective cohort study

ObjectivesTo evaluate the safety of ultrasound-guided high-intensity focused ultrasound (HIFU) ablation for patients with diffuse adenomyosis.MethodsThis was a retrospective cohort study. The data was collected from 417 symptomatic adenomyosis patients who underwent ultrasound-guided HIFU between January 2012 and December 2015 at 1st Affiliated Hospital of Chongqing Medical University, Chongqing, China. Among them were 260 patients with diffuse adenomyosis (Group D) and 157 patients with focal adenomyosis (Group F). All patients underwent contrast-enhanced magnetic resonance imaging (MRI) one week before and the day after HIFU treatment. Successful treatment with HIFU was measured by the non-perfused volume ratio (NPVR). Intraprocedural and postprocedural adverse effects and complications were recorded to assess the safety of the procedure. Patients were followed-up for three months post-treatment. Complications were given a grade A through F according to the SIR Standards.ResultsAll patients successfully completed the procedure, non-perfused regions appeared in 415 (99.5%) patients. The non-perfused volume ratio (NPVR) of Group D was significantly lower than that of Group F (P < 0.05). During the procedure, the odds ratio of skin-burning pain was 1.7 (OR = 1.617, 95% CI: 1.103–2.532), when comparing Group D with Group F, while the odds ratio of inguinal pain was equal to 2.0 (OR = 2.038, 95% CI: 1.161–3.580), when Group F was compared to Group D. 97 patients (23.3%) received nominal therapy due to complications ([Society of interventional radiology, SIR]-B grade), among them, there were 62 cases (23.8%) in Group D and 35 cases (22.3%) in Group F. No significant difference was found between the two groups (P > 0.05) and neither of the reported complications of SIR-C-SIR-F occurred within the two groups.ConclusionsBased on our results, ultrasound-guided HIFU is safe for the treatment of diffuse adenomyosis, and controlling the ablation zone is crucial to ensure patients’ safety.     

Effect of pulsed ultrasound on the physicochemical characteristics and emulsifying properties of squid (Dosidicus gigas) mantle proteins

Food technologists are always looking to improve the functional properties of proteins. In this sense, in last years ultrasound has been used to improve some functional properties. For this reason, and considering that jumbo squid is an important fishery in northwest Mexico, the purpose of this research was to determine the effect of pulsed ultrasound on the physicochemical characteristics and emulsifying properties of squid (Dosidicus gigas) mantle proteins. Pulsed ultrasound (20 kHz, 20, and 40% amplitude) was applied for 30, 60, and 90 s to a protein extract prepared from giant squid mantle causing an increase (p < 0.05) in surface hydrophobicity (S_o) from 108.4 ± 1.4 to 239.1 ± 2.4 after application of pulsed ultrasound at 40% of amplitude for 90 s. The electrophoretic profile and the total and reactive sulfhydryl contents were not affected (p ⩾ 0.05) by the ultrasound treatment. The emulsifying ability of the protein solution was improved (p < 0.05), whereas the Emulsifier Activity Index (EAI) varied from123.67 ± 5.52 m²/g for the control and increased up to 217.7 ± 3.8 m²/g after application of the ultrasound. The Stability Emulsifier Index (EEI) was improved at 40% of amplitude by 60 and 90 s. The results suggested that pulsed ultrasound used as pretreatment induced conformational changes in giant squid proteins, which improved the interfacial association between protein-oil phases, thus contributing to the improvement of their emulsifient properties.     

Synergetic effects of ultrasound and slightly acidic electrolyzed water against Staphylococcus aureus evaluated by flow cytometry and electron microscopy

This study evaluated the synergetic effects of ultrasound and slightly acidic electrolyzed water (SAEW) on the inactivation of Staphylococcus aureus using flow cytometry and electron microscopy. The individual ultrasound treatment for 10 min only resulted in 0.36 log CFU/mL reductions of S. aureus, while the SAEW treatment alone for 10 min resulted in 3.06 log CFU/mL reductions. The log reductions caused by combined treatment were enhanced to 3.68 log CFU/mL, which were greater than the sum of individual treatments. This phenomenon was referred to as synergistic effects. FCM analysis distinguished live and dead cells as well as revealed dynamic changes in the physiological states of S. aureus after different treatments. The combined treatment greatly reduced the number of viable but nonculturable (VBNC) bacteria to 0.07%; in contrast, a single ultrasound treatment for 10 min induced the formation of VBNC cells to 45.75%. Scanning and transmission electron microscopy analysis revealed that greater damage to the appearance and ultrastructure of S. aureus were achieved after combined ultrasound-SAEW treatment compared to either treatment alone. These results indicated that combining ultrasound with SAEW is a promising sterilization technology with potential uses for environmental remediation and food preservation.     

Experimental study on the influence of low-frequency and low-intensity ultrasound on the permeability of the Mycobacterium smegmatis cytoderm and potentiation with levofloxacin

Tuberculosis is an infectious disease caused by the bacterium M. tuberculosis. The aim of this study was to investigate the bactericidal effect and underlying mechanisms of low-frequency and low-intensity ultrasound combined with levofloxacin treatment against M. smegmatis (a surrogate of M. tuberculosis). As part of this study, M. smegmatis was continuously irradiated with low frequency ultrasound (42 kHz) using several different doses whereby both intensity (0.138, 0.190 and 0.329 W/cm²) and exposure time (5, 15 and 20 min) were varied. Flow cytometric analyses revealed that the permeability of M. smegmatis increased following ultrasound exposure. The survival rate, structure and morphology of bacteria in the lower-dose (I_SATA = 0.138 W/cm² for 5 min) ultrasound group displayed no significant differences upon comparison with the untreated group. However, the survival rate of bacteria was significantly reduced and the bacterial structure was damaged in the higher-dose (I_SATA = 0.329 W/cm² for 20 min) ultrasound group. Ultrasound irradiation (0.138 W/cm²) was subsequently applied to M. smegmatis in combination with levofloxacin treatment for 5 min. The results demonstrated that the bactericidal effect of ultrasonic irradiation combined with levofloxacin is higher compared to ultrasound alone or levofloxacin alone.     

Sonoluminescence characterization of inertial cavitation inside a BSA phantom treated by pulsed HIFU

The aim of this study was to investigate the inertial cavitation inside a phantom treated by pulsed HIFU (pHIFU). Basic bovine serum albumin (BSA) phantoms without any inherent ultrasound contrast agents (UCAs) or phase-shift nano-emulsions (PSNEs) were used. During the treatment, sonoluminescence (SL) recordings were performed to characterize the spatial distribution of inertial cavitation adjacent to the focal region. High-speed photographs and thermal coagulations, comparing with the SL results, were also recorded and presented. A series of pulse parameters (pulse duration (PD) was between 1 and 23 cycles and pulse repetition frequency (PRF) was between 0.5 kHz and 100 kHz) were performed to make a systematic investigation under certain acoustic power (APW). Continuous HIFU (cHIFU) investigation was also performed to serve as control group. It was found that, when APW was 19.5 W, pHIFU with short PD was much easier to form SL adjacent to the focal region inside the phantom, while it was difficult for cHIFU to generate cavitation bubbles. With appropriate PD and PRF, the residual bubbles of the previous pulses could be stimulated by the incident pulses to oscillate in a higher level and even violently collapse, resulting to enhanced physical thermogenesis. The experimental results showed that the most violent inertial cavitation occurs when PD was set to 6 cycles (5 μs) and PRF to 10 kHz, while the highest level of thermal coagulation was observed when PD was set to 10 cycles. The cavitational and thermal characteristics were in good correspondence, exhibiting significant potentiality regarding to inject-free cavitation bubble enhanced thermal ablation under lower APW, compared to the conventional thermotherapy.     

Ultrasonic pilot-scale reactor for enzymatic bleaching of cotton fabrics

The potential of ultrasound-assisted technology has been demonstrated by several laboratory scale studies. However, their successful industrial scaling-up is still a challenge due to the limited pilot and commercial sonochemical reactors. In this work, a pilot reactor for laccase-hydrogen peroxide cotton bleaching assisted by ultrasound was scaled-up. For this purpose, an existing dyeing machine was transformed and adapted by including piezoelectric ultrasonic devices. Laboratory experiments demonstrated that both low frequency, high power (22 kHz, 2100 W) and high frequency, low power ultrasounds (850 kHz, 400 W) were required to achieve satisfactory results. Standard half (4 g/L H₂O₂ at 90 °C for 60 min) and optical (8 g/L H₂O₂ at 103 °C for 40 min) cotton bleaching processes were used as references. Two sequential stages were established for cotton bleaching: (1) laccase pretreatment assisted by high frequency ultrasound (850 kHz, 400 W) and (2) bleaching using high power ultrasound (22 kHz, 2100 W). When compared with conventional methods, combined laccase-hydrogen peroxide cotton bleaching with ultrasound energy improved the whitening effectiveness. Subsequently, less energy (temperature) and chemicals (hydrogen peroxide) were needed for cotton bleaching thus resulting in costs reduction. This technology allowed the combination of enzyme and hydrogen peroxide treatment in a continuous process. The developed pilot-scale reactor offers an enhancement of the cotton bleaching process with lower environmental impact as well as a better performance of further finishing operations.     

Ultrasound-assisted extraction of rare-earth elements from carbonatite rocks

In view of the increasing demand for rare-earth elements (REE) in many areas of high technology, alternative methods for the extraction of these elements have been developed. In this work, a process based on the use of ultrasound for the extraction of REE from carbonatite (an igneous rock) is proposed to avoid the use of concentrated reagents, high temperature and excessive extraction time. In this pioneer work for REE extraction from carbonatite rocks in a preliminary investigation, ultrasonic baths, cup horn systems or ultrasound probes operating at different frequencies and power were evaluated. In addition, the power released to the extraction medium and the ultrasound amplitude were also investigated and the temperature and carbonatite mass/volume of extraction solution ratio were optimized to 70 °C and 20 mg/mL, respectively. Better extraction efficiencies (82%) were obtained employing an ultrasound probe operating at 20 kHz for 15 min, ultrasound amplitude of 40% (692 W dm⁻³) and using a diluted extraction solution (3% v/v HNO₃ + 2% v/v HCl). It is important to mention that high extraction efficiency was obtained even using a diluted acid mixture and relatively low temperature in comparison to conventional extraction methods for REE. A comparison of results with those obtained by mechanical stirring (500 rpm) using the same conditions (time, temperature and extraction solution) was carried out, showing that the use of ultrasound increased the extraction efficiency up to 35%. Therefore, the proposed ultrasound-assisted procedure can be considered as a suitable alternative for high efficiency extraction of REE from carbonatite rocks.     

Ultrasound assisted acid catalyzed lactose hydrolysis: Understanding into effect of operating parameters and scale up studies

The current work deals with the value addition of lactose by transforming into hydrolyzed lactose syrup containing glucose and galactose in major proportion using the novel approach of ultrasound assisted acid catalyzed lactose hydrolysis. The hydrolysis of lactose was performed in ultrasonic bath (33 kHz) at 50% duty cycle at different temperatures as 65 °C and 70 °C and two different hydrochloric acid (HCl) concentrations as 2.5 N and 3 N. It was observed that acid concentration, temperature and ultrasonic treatment were the major factors in deciding the time required to achieve ∼90% hydrolysis. The ultrasonic assisted approach resulted in reduction in the reaction time and the extent of intensification was established to be dependent on the temperature, acid concentration and time of ultrasonic exposure. It was observed that the maximum process intensification obtained by introduction of ultrasound in the lactose hydrolysis process performed at 70 °C and 3 N HCl was reduction in the required time for ∼90% hydrolysis from 4 h (without the presence of ultrasound) to 3 h. The scale-up study was also performed using an ultrasonic bath with longitudinal horn (36 kHz as operating frequency) at 50% duty cycle, optimized temperature of 70 °C and acid concentration of 3 N. It was observed that the reaction was faster in the presence of ultrasound and stirring by axial impeller at rpm of 225 ± 25. The time required to complete ∼90% of hydrolysis remained almost the same as observed for small scale study on ultrasonic bath (33 kHz) at 50% duty cycle. The use of recovered lactose from whey samples instead of pure lactose did not result in any significant changes in the progress of hydrolysis, confirming the efficacy of the selected approach. Overall, the work has presented a novel ultrasound assisted approach for intensified lactose hydrolysis.     

Effects of ultrasonic treatment on the maturation of Zhenjiang vinegar

High-quality vinegars are traditionally produced by aging them in barrels or bottles. However, these processes are very time-consuming. To accelerate of Zhenjiang vinegar maturation, the ultrasound was used to treat the steeped vinegar. Results showed that, the optimum ultrasonic power, time and ethanol addition for aging vinegar were determined to be 50 W/100 mL, 75 min and 0.75% (V/V), respectively. Under the optimum experimental conditions, the total amino acid of fresh vinegar decreased from 1082.259 mg/100 mL to 871.045 mg/100 mL. Several volatile components increased significantly, such as the total esters, aldehydes and heterocyclic. Total non-volatile organic acids increased from 202.59 mg/10 mL to 233.87 mg/10 mL. The changes of above-mentioned components develop towards the direction of mature vinegar. Coupling the HS-SPME/GC–MS analysis data with Principal Components Analysis, ultrasonic treatment vinegar was determined to be equivalent to 2–3 years of natural aged Zhenjiang vinegar. This study has showed that ultrasound is promising not only in shortening the aging time and lowering costs for the vinegar-making industry, but also in producing fine vinegar.     

Synergism between ultrasonic pretreatment and white rot fungal enzymes on biodegradation of wheat chaff

Lignocellulosic biomass samples (wheat chaff) were pretreated by ultrasound (US) (40 kHz/0.5 W cm⁻²/10 min and 400 kHz/0.5 W cm⁻²/10 min applied sequentially) prior to digestion by enzyme extracts obtained from fermentation of the biomass with white rot fungi (Phanerochaete chrysosporium or Trametes sp.). The accessibility of the cellulosic components in wheat chaff was increased, as demonstrated by the increased concentration of sugars produced by exposure to the ultrasound treatment prior to enzyme addition. Pretreatment with ultrasound increased the concentration of lignin degradation products (guaiacol and syringol) obtained from wheat chaff after enzyme addition. In vitro digestibility of wheat chaff was also enhanced by the ultrasonics pretreatment in combination with treatment with enzyme extracts. Degradation was enhanced with the use of a mixture of the enzyme extracts compared to that for a single enzyme extract.     

Advanced oxidation processes (AOPs) involving ultrasound for waste water treatment: A review with emphasis on cost estimation

Two things are needed for any technology to be suitable for use in the industry, viz. 1. Technical feasibility and 2. Economical feasibility. The use of ultrasound for waste water treatment has been shown to be technically feasible by numerous reports in the literature over the years. But there are hardly any exhaustive reports which address the issue of economical feasibility of the use of ultrasound for waste water treatment on industrial scale.Hence an attempt was made to estimate the cost for the waste water treatment using ultrasound. The costs have been calculated for 1000 L/min capacity treatment plant. The costs were calculated based upon the rate constants for pollutant degradation. The pollutants considered were phenol, trichloroethylene (TCE) and reactive azo dyes. Time required for ninety percent degradation of pollutant was taken as the residence time. The amount of energy required to achieve the target degradation was calculated from the energy density (watt/ml) used in the treatability study. The cost of treatment was calculated by considering capital cost and operating cost involved for the waste water treatment. Quotations were invited from vendors to ascertain the capital cost of equipments involved and operating costs were calculated based on annual energy usage. The cost was expressed in dollars per 1000 gallons of waste water treated. These treatment costs were compared with other established Advanced Oxidation Process (AOP) technologies. The cost of waste water treatment for phenol was in the range of $89 per 1000 gallons for UV/US/O₃ to $15,536 per 1000 gallons for US alone. These costs for TCE were in the range of $25 per 1000 gallons to $91 for US + UV treatment and US alone, respectively. The cost of waste water treatment for reactive azo dyes was in the range of $65 per 1000 gallon for US + UV + H₂O₂ to $14,203 per 1000 gallon for US alone.This study should help in quantifying the economics of waste water treatment using ultrasound on industrial scale. We strongly believe that this study will immensely help the researchers working in the area of applications of ultrasound for waste water treatment in terms of where the technology stands today as compared to other available commercial AOP technologies. This will also help them think for different ways to improve the efficiency of using ultrasound or search for other ways of generating cavitation which may be more efficient and help reduce the cost of treatment in future.     

Evaluation of ultrasound based sterilization approaches in terms of shelf life and quality parameters of fruit and vegetable juices

The present work evaluates the performance of ultrasound based sterilization approaches for processing of different fruit and vegetable juices in terms of microbial growth and changes in the quality parameters during the storage. Comparison with the conventional thermal processing has also been presented. A novel approach based on combination of ultrasound with ultraviolet irradiation and crude extract of essential oil from orange peels has been used for the first time. Identification of the microbial growth (total bacteria and yeast content) in the juices during the subsequent storage and assessing the safety for human consumption along with the changes in the quality parameters (Brix, titratable acidity, pH, ORP, salt, conductivity, TSS and TDS) has been investigated in details. The optimized ultrasound parameters for juice sterilization were established as ultrasound power of 100 W and treatment time of 15 min for the constant frequency operation (20 kHz). It has been established that more than 5 log reduction was achieved using the novel combined approaches based on ultrasound. The treated juices using different approaches based on ultrasound also showed lower microbial growth and improved quality characteristics as compared to the thermally processed juice. Scale up studies were also performed using spinach juice as the test sample with processing at 5 L volume for the first time. The ultrasound treated juice satisfied the microbiological and physiochemical safety limits in refrigerated storage conditions for 20 days for the large scale processing. Overall the present work conclusively established the usefulness of combined treatment approaches based on ultrasound for maintaining the microbiological safety of beverages with enhanced shelf life and excellent quality parameters as compared to the untreated and thermally processed juices.     

Quality properties of pre- and post-rigor beef muscle after interventions with high frequency ultrasound

The delivery of a consistent quality product to the consumer is vitally important for the food industry. The aim of this study was to investigate the potential for using high frequency ultrasound applied to pre- and post-rigor beef muscle on the metabolism and subsequent quality. High frequency ultrasound (600 kHz at 48 kPa and 65 kPa acoustic pressure) applied to post-rigor beef striploin steaks resulted in no significant effect on the texture (peak force value) of cooked steaks as measured by a Tenderometer. There was no added benefit of ultrasound treatment above that of the normal ageing process after ageing of the steaks for 7 days at 4 °C. Ultrasound treatment of post-rigor beef steaks resulted in a darkening of fresh steaks but after ageing for 7 days at 4 °C, the ultrasound-treated steaks were similar in colour to that of the aged, untreated steaks. High frequency ultrasound (2 MHz at 48 kPa acoustic pressure) applied to pre-rigor beef neck muscle had no effect on the pH, but the calculated exhaustion factor suggested that there was some effect on metabolism and actin-myosin interaction. However, the resultant texture of cooked, ultrasound-treated muscle was lower in tenderness compared to the control sample. After ageing for 3 weeks at 0 °C, the ultrasound-treated samples had the same peak force value as the control. High frequency ultrasound had no significant effect on the colour parameters of pre-rigor beef neck muscle. This proof-of-concept study showed no effect of ultrasound on quality but did indicate that the application of high frequency ultrasound to pre-rigor beef muscle shows potential for modifying ATP turnover and further investigation is warranted.     

Effect of novel ultrasound based processing on the nutrition quality of different fruit and vegetable juices

Increasing consumer awareness regarding the health benefits of different nutrients in food have led to the requirement of assessing the effect of food processing approaches on the quality attributes. The present work focuses on understanding the effects of novel approaches based on the use of ultrasound and ultraviolet irradiations on the nutritional quality of different fruit and vegetable juices (orange, sweet lime, carrot and spinach juices) and its comparison with the conventional thermal pasteurization operated at 80 °C for 10 min. The ultrasound sterilization parameters were maintained at ultrasound frequency of 20 kHz and power of 100 W with treatment time as 15 min. For the case of ultraviolet irradiations, 2 UVC lamps (254 nm) of 8 W were placed in parallel on either sides of the reactor. The treated juices were analyzed for total phenol content, antioxidant activity, vitamin C, carbohydrates etc. It has been established that ultrasound processed juice retained most of the nutrient components to higher extent in comparison to all the other techniques used in the work. Combination of ultrasound and ultraviolet irradiations used to achieve an effective decontamination of juices (recommended 5 log reduction of microorganisms) also retained nutrients to a higher level in comparison to the thermal method; however some losses were observed as compared to the use of only ultrasound which could be attributed to inefficient heat exchange in the combined approach. A scale up attempt was also made for treatment of spinach juice using ultrasonic reactors and analysis for quality attributes confirmed that the juice satisfied the criteria of required nutrient contents for 18 days shelf life trial in refrigerated storage conditions. The present work has clearly established the usefulness of ultrasound based treatment in maintaining the nutritional quality of beverages while giving enhanced shelf life as compared to the conventional approaches.     

Ultrasound-mediated destruction of oxygen and paclitaxel loaded lipid microbubbles for combination therapy in hypoxic ovarian cancer cells

We synthesized oxygen and paclitaxel (PTX) loaded lipid microbubbles (OPLMBs) for ultrasound mediated combination therapy in hypoxic ovarian cancer cells. Our experiments successfully demonstrated that ultrasound induced OPLMBs destruction significantly enhanced the local oxygen release. We also demonstrated that OPLMBs in combination with ultrasound (300 kHz, 0.5 W/cm², 15 s) yielded anti-proliferative activities of 52.8 ± 2.75% and cell apoptosis ratio of 35.25 ± 0.17% in hypoxic cells at 24 h after the treatment, superior to other treatment groups such as PTX only and PTX-loaded MBs (PLMBs) with or without ultrasound mediation. RT-PCR and Western blot tests further confirmed the reduced expression of HIF-1α and MDR-1/P-gp after ultrasound mediation of OPLMBs. Our experiment suggests that ultrasound mediation of oxygen and drug-loaded MBs may be a useful method to overcome chemoresistance in the hypoxic ovarian cancer cells.     

Molecular weight distribution,rheological property and structural changes of sodium alginate induced by ultrasound

In this study, the effects of ultrasound with different ultrasonic frequencies on the properties of sodium alginate (ALG) were investigated, which were characterized by the means of the multi-angle laser light scattering photometer analysis (GPC-MALLS), rheological analysis, circular dichroism (CD) spectrometer and scanning electron microscope (SEM). It showed that the molecular weight (M_w) and molecular number (M_n) of the untreated ALG was 1.927 × 10⁵ g/mol and 4.852 × 10⁴ g/mol, respectively. The M_w of the ultrasound treated ALG was gradually increased from 3.50 × 10⁴ g/mol to 7.34 × 10⁴ g/mol while the M_n of ALG was increased and then decreased with the increase of the ultrasonic frequency. The maximum value of M_n was 9.988 × 10⁴ g/mol when the ALG was treated by ultrasound at 40 kHz. It indicated that ultrasound could induce ALG degradation and rearrangement. The number of the large molecules and small molecules of ALG was changed by ultrasound. The value of d_n/d_c suggested that the ultrasound could enhance the stability of ALG. Furthermore, it was found that ALG treated by ultrasound at 50 kHz tended to be closer to a Newtonian behavior, while the untreated and treated ALG solutions exhibited pseudoplastic behaviours. Moreover, CD spectra demonstrated that ultrasound could be used to improve the strength of the gel by changing the ratio of M/G, which showed that the minimum ratio of M/G of ALG treated at 135 kHz was 1.34. The gel-forming capacity of ALG was correlated with the content of G-blocks. It suggested that ALG treated by ultrasound at 135 kHz was stiffer in the process of forming gels. The morphology results indicated that ultrasound treatment of ALG at 135 kHz increased its hydrophobic interaction and interfacial activity. This study is important to explore the effect of ultrasound on ALG in improving the physical properties of ALG as food additives, enzyme and drug carriers.     

Synergistic effect of ultrasonic pre-treatment combined with UV irradiation for secondary effluent disinfection

The ultraviolet (UV) disinfection efficiency is often affected by suspended solids (SS). Given their high concentration or large particle size, SS can scatter UV light and provide shielding for bacteria. Thus, ultrasound is often employed as a pre-treatment process to improve UV disinfection. This work investigated the synergistic effect of ultrasound combined with UV for secondary effluent disinfection. Bench-scale experiments were conducted in using samples obtained from secondary sedimentation tanks. These tanks belonged to three wastewater treatment plants in Beijing that use different kinds of biological treatment methods. Several parameters may contribute to the changes in the efficiency of ultrasound and UV disinfection. Thus, the frequency and energy density of ultrasound, as well as the SS, were investigated. Results demonstrated that samples which have relatively higher SS concentrations or higher percentages of larger particles have less disinfection efficiency using UV disinfection alone. However, the presence of ultrasound could improve the disinfection efficiency because it has synergistic effect. Changes in the particle size distribution and SS concentration notably affected the efficiency of UV disinfection. The efficiency of Escherichia coli elimination can be decreased by 1.2 log units as the SS concentration increases from 16.9 mg/l to 25.4 mg/l at a UV energy density of 40 mJ/cm². UV disinfection alone reduced the E. coli population by 3.4 log units. However, the synergistic disinfection of ultrasound and UV could reach 5.4 log units during the reduction of E. coli at a 40 kHz frequency and an energy density of 2.64 kJ/l. The additional synergistic effect is 1.1 log units.