Effect Of Low-Frequency Ultrasound Research Articles

Investigation on The Effect of Low Frequency Ultrasound on The Crystallization of a Pharmaceutical Compound L+ Ascorbic Acid

One of the most crucial processes in the chemical processing industry is crystallization, which has the major challenge of producing solid products with the required purity and properties. The standard crystallization methods have various processing limitations; hence, research into alternative methods like ultrasonic-assisted crystallization has been at the forefront. The present work investigates the application of low-frequency ultrasound irradiation (40 kHz) for improving the cooling crystallization of ascorbic acid. The impact of ultrasonic irradiation on crystal size, shape, and induction time has been studied, and a comparison with the conventional method has been made. The standing time had a minor effect on particle size on average, while the initial temperature had a far more significant impact. Photographic analysis using image-analysis software indicated that when ultrasound was applied to the saturated solutions, the resulting crystals were smaller and more uniform in size and shape. The resultant crystal grows predominantly in a single direction, resembling thin prisms. The use of ultrasound was also shown to reduce the induction time significantly. This ultrasonic impact is stronger at lower initial temperatures. Indeed, the smallest induction time of 300 s was obtained for sonicated solutions at an initial temperature of 65°C and ultrasonic power of 250 w. When different levels of ultrasonic power dissipation were tested, it was established that the time required for the first nuclei to appear decreased as the power increased. There was, nevertheless, a marginal impact on average crystal size.

Effects of Low-Frequency Ultrasound on Microcystis aeruginosa from Cell Inactivation to Disruption.

Ultrasound can be used to induce cell resonance and cavitation to inhibit cyanobacterial growth, but it can also lead to increase in dissolved nutrients because of cell disruption. This study investigated the process from cell inactivation to disruption of Microcystis aeruginosa. Algal cells were sonicated (at 35kHz) under various intensities and durations. Results showed that chlorophyll a content and Fv/Fm values decreased slightly within the first 5min. Superoxide dismutase activity was stimulated and its peak value appeared at the fifth minute. After 20min, considerable number of ruptured cells were observed and the concentrations of dissolved nitrogen and phosphorus increased rapidly. Finally, ammonia and nitrate merely composed a small portion of dissolved nitrogen. This study demonstrated that excessive ultrasound treatment can significantly rupture algal cells and lead to the release of cellular inclusions, which may cause ecological issues or public health problems. Based on our findings, ultrasonic intensity controlled at 0.035W/mL and applied for a duration of 20min delivers the optimal result in effectively inhibiting physiological activities of Microcystis aeruginosa without marked cell disruption. This will ultimately help to achieve algal control, while conserving energy and preserving the environment and human health.

Effects of Low Frequency Ultrasound on Adriamycin (ADR) Uptake and Cell Growth in Breast Cancer Cells

1. Physical Therapy, Winston Salem State University, Winston Salem, NC, United States. 2. Pathology, Wake Forest University School of Medicine, Winston Salem, NC, United States.

EFFECTS OF LOW FREQUENCY ULTRASOUND COMPARE WITH HIGH FREQUENCY ULTRASOUND IN KNEE OSTEOARTHRITIS

OBJECTIVE To compare the effectiveness of low and high frequency ultrasound (US) technique for treatment of osteoarthritis (OA) of knee joint. It is a pre-post design was used with multiple treatment therapies (A and B). The study was conducted on the 310 patients. The patients were diagnosed knee OA by the orthopedic doctor and recommended to the Physiotherapy department of North and Clifton Campus of Ziauddin Hospital. In this study 310 patients were divided into two groups. Group A of 155 patients received low frequency US treatment of 0.01MHz frequency for 10 min and at the same time Group B of 155 patients received high frequency US treatment of 1MHz for about 3 min. Both the groups had 6 sessions in 3 weeks. There was a mean reduction in the pain and disability with difference of low frequency US and high frequency US pre score and post score treatments of both the groups is 1.2± 0.3 and 4.1± 1.0, there was statistically significant difference between the effects of low frequency US and high frequency US in pain management of knee O.A (P < 0.05). There was difference between the effectiveness of low frequency US

Short-Term In Vitro Effects of Low Frequency Ultrasound on Odontoblast-Like Cells

In this study, the effects of low frequency ultrasound (US) were examined on odontoblasts, the primary cell responsible for dentinogenesis and dentine repair. An established odontoblast-like cell line, MDPC-23, was subjected to 30 kHz ultrasound at three different power settings. US induced a marginal level of cell death (3% to 4%) at lower amplitudes rising to 25% cell death at the highest power tested. The latter was reflected in a 30% decrease in cell attachment after 4 to 24 h of culture, while the number of adherent cells was reduced by approximately 10% to 15% in the lower power groups. Cell replication after 24 h, as measured by BrdU incorporation, showed no significant changes in the US-treated groups. Gene expression analyses demonstrated a moderate dose-dependent increase in the expression of GAPDH (glyseraldehyde-3-phosphate dehydrogenase)-normalised collagen type I, osteopontin (OPN), transforming growth factor-β1 (TGFβ1) and the heat shock protein (hsp) 70. The greatest change was found in the expression of the small hsp 25/27, which showed a two- to six-fold increase following US treatment. No significant effects were observed for alkaline phosphatase (ALP) and core-binding factor A1 (CBFA1/Runx2) expression levels. This is the first report describing US effects on odontoblasts. Further studies are warranted to elucidate US effects on odontoblast function and to evaluate US as a therapeutic application in dentine repair. (E-mail: b.a.scheven@bham.ac.uk)

The effect of 40 kHz ultrasound on tissue plasminogen activator-induced clot lysis in three in vitro models

In a previous study, high-frequency ultrasound (US) (3 MHz) was shown to enhance in vitro fibrinolysis through enhanced supply of plasminogen to the clot surface. The application of high-frequency US is limited in vivo, however, due to tissue heating. We continued our research using low-frequency US with less tissue heating and improved penetration of the US. Three different in vitro models, internal plasma clot lysis and external lysis with compacted and noncompacted plasma clots, were used to determine the magnitude of the effect of low-frequency US (40 kHz; 0.5 W/cm 2) on tissue plasminogen activator-induced lysis and to elucidate the mechanisms behind the effect. US enhanced lysis in all three models, with the largest effects (fourfold) being in the compacted plasminogen-poor clot model. Plasminogen supply to the clot surface was again shown to be an important contributor to US-enhanced lysis. (E-mail: d.rijken@erasmusmc.nl)

Therapeutic Ultrasound in Lower Extremity Wound Management

In medical practice, ultrasound (US) is used for diagnosis and therapy. High-frequency (1-4 MHz) and low-frequency (20-120 KHz) therapeutic US are relevant to wound healing. The heating effects of high-frequency US are important, whereas the mechanical effects of low-frequency US must be considered. The physiological effects of low-frequency US include metabolic enhancement, perfusion, wound cleansing, and the acceleration of wound granulation. The therapeutic efficacy of US depends on dose (W/cm (2) time)and dosage (frequency of application, series). At adequate doses, high-frequency and low-frequency therapeutic US induce in vitro cell proliferation; protein synthesis; and the production of cytokines by fibroblasts, osteoblasts, and monocytes. The mechanical effects of low-frequency US cause transient cavitation in wound surfaces for soft and smooth wound cleaning, ulcer debridement, and the stimulation of granulation. These effects can be determined in clinical studies, though the quality of the studies done so far and of the evidence of the usefulness of US is poor. Nevertheless, high-frequency and low-frequency US may be reasonable options in the management of chronic wounds.

Comparison of the effect of ultrasound and of chemical enhancers on transdermal permeation of caffeine and morphine through hairless mouse skin in vitro

The effect of ultrasound (US) on permeation of two model drugs, caffeine (CAF) and morphine (MOR), through hairless mouse skin in vitro was compared with that of three chemical enhancers. Low-frequency (40 KHz), low-power (<0.5 W/cm 2) US was used; the effect of high-frequency US (1.5–3.0 MHz) was also evaluated in the case of CAF. The chemical enhancers, tested in combination with propylene glycol (PG), were benzalkonium chloride (BAC) oleyl alcohol (OA) and α-terpineol (TER). The high-frequency US enhancement of CAF transdermal flux was not statistically significant, while low frequency produced a small but significant increase of the enhancement factor. The effect of US on CAF permeation, however, was lower than that produced by chemical enhancers, in particular OA. The effect of low-frequency US on permeation of MOR was significantly greater (about 10-fold) when compared, on the same frequency and intensity basis, with the effect on CAF. The most active chemical enhancer for MOR, OA, had practically the same effect as low-frequency US. Sonicated skin, although showing slight histological changes, recovered its original low permeability characteristics after turning off sonication. Within the tested system, chemical enhancement appears to offer some advantages over low-frequency US.

The effects of low-frequency ultrasound on Staphylococcus epidermidis.

Low frequency ultrasound (LFUS) significantly enhances skin permeability to a variety of drugs; however, its bacterial effects have not been well studied. Staphylococcus epidermidis organisms were grown and standardized to 10(5) cfu/ml 24 h prior to investigation and suspended in normal saline. LFUS was applied with two probes immersed in the bacterial suspensions over a range of suspension volumes, intensities, and exposure times. The suspension temperature was measured, and a sample was removed, streaked onto blood agar plates, and incubated at 37 degrees C for 24 h. Quantitative bacterial counts were then obtained. LFUS resulted in significant reductions in bacterial counts that correlated with fluid temperature. Probe size and ultrasound intensity appeared to affect bacterial counts, but were also correlated with temperature. Bacterial growth was minimal with temperatures exceeding 45 degrees C. While LFUS can reduce bacterial counts, these conditions have the potential to cause burns in humans.

Effects of Low Frequency Ultrasound on Properties of Restructured Beef Rolls

ABSTRACTThe effects of low frequency ultrasound on exudate yield, breaking strength, cooking yield, water‐holding capacity, color, and muscle microstructure were investigated by exposing pieces of lean muscle to slow tumbling and low frequency ultrasonic waves. Results indicated that beef rolls exposed to low frequency ultrasound without added salt were superior in breaking strength and cooking yield to those tumbled with neither ultrasound nor salt and were comparable in breaking strength, cooking yield, exudate yield and water‐holding capacity to those tumbled with salt and no ultrasound exposure. Furthermore, the beef rolls exposed to ultrasound and no salt were superior in color to those to which salt was added. Low frequency ultrasound caused muscle fiber disruption and separation of up to approximately 1 cm in depth in muscle micro‐structure in the pieces of lean muscle.