scholarly journals Simulation Study on the Influence of Multifrequency Ultrasound on Transient Cavitation Threshold in Different Media

2020 ◽  
Vol 10 (14) ◽  
pp. 4778
Author(s):  
Hu Dong ◽  
Xiao Zou ◽  
Shengyou Qian
Keyword(s):  
Negative Pressure ◽  
Bubble Radius ◽  
Frequency Difference ◽  
Single Frequency ◽  
Polytropic Index ◽  
Phase Angle Difference ◽  
Triple Frequency ◽  
Peak Negative Pressure ◽  
Cavitation Threshold ◽  
Frequency Ultrasound

Through the introduction of multifrequency ultrasound technology, remarkable results have been achieved in tissue ablation and other aspects. By using the nonlinear dynamic equation of spherical bubble, the effects of the combination mode of multifrequency ultrasound, the peak negative pressure and its duration, the phase angle difference, and the polytropic index on the transient cavitation threshold in four different media of water, blood, brain, and liver are simulated and analyzed. The simulation results show that under the same frequency difference and initial bubble radius, the transient cavitation threshold of the high-frequency, triple-frequency combination is higher than that of the low-frequency, triple-frequency combination. When the lowest frequency of triple frequencies is the same, the larger the frequency difference, the higher the transient cavitation threshold. When the initial bubble radius is small, the frequency difference has little effect on the transient cavitation threshold of the triple-frequency combination. With the increase of initial bubble radius, the influence of frequency difference on the transient cavitation threshold of the higher frequency combination of triple frequency is more obvious than that of the lower frequency combination of triple frequency. When the duration of peak negative pressure or peak negative pressure of the multifrequency combined ultrasound is longer than that of the single-frequency ultrasound, the transient cavitation threshold of the multifrequency combined ultrasound is lower than that of the single-frequency ultrasound; on the contrary, the transient cavitation threshold of the multifrequency combined ultrasound is higher than that of the single-frequency ultrasound. When the phase angle difference of multifrequency excitation is zero, the corresponding transient cavitation threshold is the lowest, while the change of the polytropic index has almost no effect on the transient cavitation threshold for the multifrequency combination. The research results can provide a reference for multifrequency ultrasound to reduce the transient cavitation threshold, which is of great significance for the practical application of cavitation.

Immobilized enzymolysis of corn gluten meal under triple-frequency ultrasound

2018 ◽  
Vol 14 (5-6) ◽  
Author(s):  
Wenjuan Qu ◽  
Raya Masoud Sehemu ◽  
Tian Zhang ◽  
Bingjie Song ◽  
Lan Yang ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Single Frequency ◽  
Antihypertensive Activity ◽  
Degree Of Hydrolysis ◽  
Corn Gluten Meal ◽  
Reaction Rate Constants ◽  
Triple Frequency ◽  
Corn Gluten ◽  
The Cost ◽  
Frequency Ultrasound

AbstractThe single frequency ultrasound mode is difficult to achieve an higher enzymolysis efficiency. The cost of protein enzymatic hydrolysis, using free enzyme is higher because the enzyme cannot be used repeatedly. Therefore, the effects of triple-frequency ultrasound (TFU) treatment on the performance, kinetics, and thermodynamics of immobilized Alcalase enzymolysis of corn gluten meal (CGM) were investigated in this research. The results showed that degree of hydrolysis (DH), peptide concentration, ACE inhibitory activity, and relative enzyme activity were increased by 20.6 %, 34.4 %, 24.1 %, and 25.8 %, respectively, by TFU treatment at the optimum conditions compared to the control. Kinetics and thermodynamic analyses revealed that TFU treatment successfully decreased the apparent constant (KM) by 27.0 % and increased the reaction rate constants (k) by 32.1 –200 % at 303.15–343.15 K. The energy of activation (Ea), enthalpy of activation (ΔH), and entropy of activation (ΔS) were reduced by 17.1 %, 15.2 –15.3 %, and 24.1 –31.8 %, respectively. Immobilized enzymolysis assisted by TFU was proved to be an efficient method to increase the enzymolysis efficiency, enzyme activity, and antihypertensive activity of the peptides through performance and mechanism discussion.

scholarly journals Nanodroplet-mediated catheter-directed sonothrombolysis of retracted blood clots

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Leela Goel ◽  
Huaiyu Wu ◽  
Bohua Zhang ◽  
Jinwook Kim ◽  
Paul A. Dayton ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Negative Pressure ◽  
Boiling Point ◽  
Clot Lysis ◽  
Control Group ◽  
Peak Negative Pressure ◽  
Blood Clots ◽  
Tissue Plasminogen ◽  
First Time

AbstractOne major challenge in current microbubble (MB) and tissue plasminogen activator (tPA)-mediated sonothrombolysis techniques is effectively treating retracted blood clots, owing to the high density and low porosity of retracted clots. Nanodroplets (NDs) have the potential to enhance retracted clot lysis owing to their small size and ability to penetrate into retracted clots to enhance drug delivery. For the first time, we demonstrate that a sub-megahertz, forward-viewing intravascular (FVI) transducer can be used for ND-mediated sonothrombolysis, in vitro. In this study, we determined the minimum peak negative pressure to induce cavitation with low-boiling point phase change nanodroplets and clot lysis. We then compared nanodroplet mediated sonothrombolysis to MB and tPA mediate techniques. The clot lysis as a percent mass decrease in retracted clots was 9 ± 8%, 9 ± 5%, 16 ± 5%, 14 ± 9%, 17 ± 9%, 30 ± 8%, and 40 ± 9% for the control group, tPA alone, tPA + US, MB + US, MB + tPA + US, ND + US, and ND + tPA + US groups, respectively. In retracted blood clots, combined ND- and tPA-mediated sonothrombolysis was able to significantly enhance retracted clot lysis compared with traditional MB and tPA-mediated sonothrombolysis techniques. Combined nanodroplet with tPA-mediated sonothrombolysis may provide a feasible strategy for safely treating retracted clots.

scholarly journals Bacterial Cell Inactivation Using a Single-Frequency Batch-Type Ultrasound Device

2021 ◽  
Vol 6 (1) ◽  
pp. 65-80
Author(s):  
Poetro Sambegoro ◽  
Maya Fitriyanti ◽  
Bentang Arief Budiman ◽  
Kamarisima Kamarisima ◽  
Sekar Wangi Arraudah Baliwangi ◽  
...  
Keyword(s):  
Bacterial Cell ◽  
Treatment Time ◽  
Low Cost ◽  
Single Frequency ◽  
Bacterial Cells ◽  
Cell Inactivation ◽  
E Coli ◽  
Commercial System ◽  
Ultrasound Device ◽  
Frequency Ultrasound

Ultrasound technology employs cavitation to generate high-pressure soundwaves to disrupt bacterial cells. This study reveals the effectiveness of a single frequency ultrasound device for bacterial cell inactivation. A low-cost ultrasound device having a single frequency, i.e. 22 kHz for lab-scale application, was developed first, and the prototype was mechanically designed and analyzed using the finite-element method to assure the targeted natural frequency could be achieved. The prototype was then tested inactivating bacterial cells, Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis), in a simple medium and a food system, and the results were then compared to a commercial system. A treatment time of up to 15 minutes was able to reduce E. coli and B. subtilis cells by 3.3 log and 2.8 log, respectively, and these results were similar to those of the commercial system. The effectiveness of bacterial cell inactivation using the developed single-frequency ultrasound device is then discussed. The findings are useful for designing low-cost ultrasound devices for application in the food industry.

The Hip Suction Seal, Part I: The Role of Acetabular Labral Height on Hip Distractive Stability

2020 ◽  
Vol 48 (11) ◽  
pp. 2726-2732 ◽  
Author(s):  
Hunter W. Storaci ◽  
Hajime Utsunomiya ◽  
Bryson R. Kemler ◽  
Samuel I. Rosenberg ◽  
Grant J. Dornan ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Clinical Effects ◽  
Acetabular Labrum ◽  
Peak Negative Pressure ◽  
Hip Stability ◽  
New Strategy ◽  
Fresh Frozen ◽  
Articular Pathology ◽  
Distraction Force ◽  
Suction Seal

Background: The acetabular labrum has been found to provide a significant contribution to the distractive stability of the hip. However, the influence of labral height on hip suction seal biomechanics is not known. Hypothesis: The smaller height of acetabular labrum is associated with decreased distractive stability. Study Design: Descriptive laboratory study. Methods: A total of 23 fresh-frozen cadaveric hemipelvises were used in this study. Hips with acetabular dysplasia or femoroacetabular impingement–related bony morphologic features, intra-articular pathology, or no measurable suction seal were excluded. Before testing, each specimen’s hip capsule was removed, a pressure sensor was placed intra-articularly, and the hip was fixed in a heated saline bath. Labral size was measured by use of a digital caliper. Maximum distraction force, distance to suction seal rupture, and peak negative pressure were recorded while the hip underwent distraction at a rate of 0.5 mm/s. Correlations between factors were analyzed using the Spearman rho, and differences between groups were detected using Mann-Whitney U test. Results: Of 23 hips, 12 satisfied inclusion criteria. The maximum distraction force and peak negative pressure were significantly correlated ( R = −0.83; P = .001). Labral height was largely correlated with all suction seal parameters (maximum distraction force, R = 0.69, P = .013; distance to suction seal rupture, R = 0.55, P = .063; peak negative pressure, R = −0.62, P = .031). Labral height less than 6 mm was observed in 5 hips, with a mean height of 6.48 mm (SD, 2.65 mm; range, 2.62-11.90 mm; 95% CI, 4.80-8.17 mm). Compared with the 7 hips with larger labra (>6 mm), the hips with smaller labra had significantly shorter distance to suction seal rupture (median, 2.3 vs 7.2 mm; P = .010) and significantly decreased peak negative pressure (median, −59.3 vs −66.9 kPa; P = .048). Conclusion: Smaller height (<6 mm) of the acetabular labrum was significantly associated with decreased distance to suction seal rupture and decreased peak negative pressure. A new strategy to increase the size of the labrum, such as labral augmentation, could be justified for patients with smaller labra in order to optimize the hip suction seal. Clinical Relevance: The height of the acetabular labrum is correlated with hip suction seal biomechanics. Further studies are required to identify the clinical effects of labral height on hip stability.

Monitoring concept of single-frequency ultrasound and its application in dynamic crystallization processes

2015 ◽  
Vol 26 (3) ◽  
pp. 874-881 ◽  
Author(s):  
D. Pertig ◽  
M. Fardmostafavi ◽  
T. Stelzer ◽  
J. Ulrich
Keyword(s):  
Single Frequency ◽  
Dynamic Crystallization ◽  
Frequency Ultrasound

scholarly journals A Multispectral Bayesian Classification Method for Increased Acoustic Discrimination of Seabed Sediments Using Multi-Frequency Multibeam Backscatter Data

Geosciences ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 455 ◽  
Author(s):  
Timo Gaida ◽  
Tengku Tengku Ali ◽  
Mirjam Snellen ◽  
Alireza Amiri-Simkooei ◽  
Thaiënne van Dijk ◽  
...  
Keyword(s):  
Ground Truth ◽  
Single Frequency ◽  
Qualitative Comparison ◽  
Ground Truth Data ◽  
Geological Interpretation ◽  
Additional Information ◽  
Triple Frequency ◽  
Acoustic Discrimination ◽  
Multiple Frequencies ◽  
Seabed Sediments

Multi-frequency backscatter data collected from multibeam echosounders (MBESs) is increasingly becoming available. The ability to collect data at multiple frequencies at the same time is expected to allow for better discrimination between seabed sediments. We propose an extension of the Bayesian method for seabed classification to multi-frequency backscatter. By combining the information retrieved at single frequencies we produce a multispectral acoustic classification map, which allows us to distinguish more seabed environments. In this study we use three triple-frequency (100, 200, and 400 kHz) backscatter datasets acquired with an R2Sonic 2026 in the Bedford Basin, Canada in 2016 and 2017 and in the Patricia Bay, Canada in 2016. The results are threefold: (1) combining 100 and 400 kHz, in general, reveals the most additional information about the seabed; (2) the use of multiple frequencies allows for a better acoustic discrimination of seabed sediments than single-frequency data; and (3) the optimal frequency selection for acoustic sediment classification depends on the local seabed. However, a quantification of the benefit using multiple frequencies cannot clearly be determined based on the existing ground-truth data. Still, a qualitative comparison and a geological interpretation indicate an improved discrimination between different seabed environments using multi-frequency backscatter.

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