Ultrasound application

Another promising technique is ultrasound application during osmotic dehydration. Used on porous fruit such as apple cubes, it affects mass... 

Marin A, Lopez-Gonzalvez A, Barbas C. Development and validation of extraction methods for determination of zinc and arsenic speciation in soils using focused ultrasound application to heavy metal study in mud and soils. Anal. Chim. Acta 2001 442 305-318. 

The barbituric acid derivative 40a-f (0.50 mmol) was ground in an agate mortar. Solid diazonium salt289j (0.50 mmol) was added and coground in five portions for 5 min each. Most of the diazonium band at 2280 cm had disappeared, but completion of the reaction was achieved by 24 h ultrasound application in a test tube. After neutralization (0.5 N NaOH, 20 mL), washing (H2O), and... 

FIGURE 16.3 Demonstration of the highly permeable localized transport regions (LTRs), which occurred after ultrasound application, on pig full-thickness skin sample. The darker regions are the LTRs, visualized in presence of Potassium Indigo. (From Wolloch L. and Kost J. Unpublished data.)... 

Few data are available on the subject of the simultaneous reaction and comminution in solid-liquid systems. This field is occupied by ultrasound applications and synthetic methods, as summarized previously [50, 101]. Of the few applications in milling devices the reduction of liquid TiCU with Mg to Ti-powder has been... 

Khanal, S.K., Grewell, D., Sung, S., and van Leeuwen, J. 2007a. Ultrasound applications in wastewater sludge pretreatment A review. Critical Reviews in Environmental Science and Technology, 37 1-37. 

Pulsed operation should not be confused with the duty cycle as used in medical ultrasound applications or adopted for pulsed operation in users manuals for commercial... 

For over 40 years, much has been done on the purported ability of high frequency or high intensity ultrasound application to disinfect and sterilize. Sterilization is defined as the... 

Amplitude of ultrasound waves can be represented in terms of peak wave pressure (in Pascals) or in terms of intensity (in the units of W/cm ). Ultrasound can be applied either continuously or in a pulsed manner. In the latter case, an additional parameter, duty cycle, is required to characterize ultrasound application. Duty cycle is the fraction of time for which ultrasound is ON. 

Ultrasound can be applied either in a continuous or a pulsed mode. A pulsed mode of ultrasound application is used many times because it reduces the severity of adverse side effects of ultrasound, such as thermal effects. However, pulsed application of ultrasound may have a significant effect on the efficacy of sonophoresis. As will be discussed later, cavitational effects, which play a crucial role in sonophoresis,... 

In a recent systematic study of the dependence of 20 kHz sonophoresis on ultrasound parameters, Mitragotri et al. showed that the enhancement of skin permeability varies linearly with ultrasound intensity and ultrasound on-time (for pulsed ultrasound, ultrasound on-time equals the product of total ultrasound application time and duty cycle), while is independent of the ultrasound duty cycle. Based on those findings, fhe authors reported that there is a threshold energy dose for ultrasound induced transdermal drug transport. Once the threshold value is crossed, the enhancement of skin permeability varies linearly with the ultrasound energy dose (J/cm ), which is calculated as the product of ultrasound intensity and ultrasound on-time. This result indicates that ultrasound energy dose can be used as a predictor of the effect of 20 kHz sonophoresis. The authors also indicated that it is important to determine the threshold energy dose for each individual sonophoresis system, for example, the real in vivo situation, because it may vary from system to system. Specifically, it may vary between different skin models, as well as with the ultrasound frequency and the distance of the transducer from the skin surface, etc. 

The most commonly used technique of sonophoresis in these studies was to apply hydrocortisone in the form of an ointment on the skin and then apply ultrasound by keeping the transducer in contact with the ointment. In some cases, the transducer was moved in circular patterns to avoid a continuous exposure of a certain part of the skin to ultrasound. Although these studies were performed using different animal models, application techniques, hydrocortisone concentrations in the ointment, and exposure time, a measurable enhancement of hydrocortisone transport was reported in almost all cases. In contrast, most of the attempts to enhance transdermal transport of lidocaine and salicylates have been less successful. In the case of lidocaine, the sonophoretic enhancement was measured in terms of reduction of onset time for anesthesia or prolonging duration of anesthesia. In most cases, no significant effect of ultrasound application on either induction time or duration of anesthesia has been reported. Similarly sonophoresis of salicylates from ointments has not been found to induce any significant increase in plasma salicylate levels. ... 

Calculate the amount of released calcein upon ultrasound application. 

DHPC increases the sensitivity of liposomes to ultrasound application. DHPC is a short chain lipid, which can stabilize broken edges of bilayers (15, 16) allowing the openings created by membrane stretch to remain open longer, allowing more contents to be released. 

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