Pancreatic cancer is characterized by extensive stromal desmoplasia, which decreases blood perfusion and impedes chemotherapy delivery. Breaking the stromal barrier could both increase perfusion and permeabilize the tumor, enhancing chemotherapy penetration. Mechanical disruption of the stroma can be achieved using ultrasound-induced bubble activity-cavitation. Cavitation is also known to resul...

Gassy and degassed aqueous solutions of DNA were treated ultrasonically while monitoring the field for discrate cavitation events. At irradiation intensities greater than about 500 W/cm 2, transient cavitation is shown to be responsible forthe observed reduction i molecular weight. At intensifies of200 to 288 W/cm 2, degradation of DNA was observed which did not depend upon transient cavitation.

Purpose: Purpose of this paper is attempt explanation how laser beam processing influence on the cavitation performance of the Fe-Cr-Mn and Fe-Cr-Co alloys. This kind of alloys are frequently used in Polish power plants to routine repairs of damaged blades working under cavitation loading. Design/methodology/approach: Padding welds of investigated alloys were tested for three cases: after laser...

Variation in intensity of scattered light from cavitation bubbles in an ultrasonic standing wave field at different contents of dissolved air is studied experimentally. The number of cavitation bubbles that repeat expansion and contraction correlates with the sonochemical reaction yield and the evaluation of the number of bubbles is important for perspective on the yield. Peak-to-peak of intens...

Recently, cavitation on the surface of mechanical heart valves has been studied as a cause of fractures occurring in implanted mechanical heart valves. The cause of cavitation in mechanical heart valves was investigated using the 25 mm Medtronic Hall valve and the 23 mm Omnicarbon valve. Closing of these valves in the mitral position was simulated in an electrohydraulic totally artificial heart...

Effects of mineral nutrition on susceptibility to cavitation were examined in four hybrid poplar clones. Two drought-sensitive and two drought-resistant hybrid clones of black cottonwood (Populus trichocarpa Torr. & Gray) and eastern cottonwood (P. deltoides Bartr.) were grown at three concentrations of nitrogen (N) applied factorially with two concentrations of phosphorus (P) in a greenhouse, ...

Superplastic materials show a very high ductility. This is due to both peculiar process conditions and material intrinsic characteristics. However, a number of superplastic materials are subjected to cavitation during superplastic deformation. Evidently, extensive cavitation imposes significant limitations on their commercial application. The deformation and failure of superplastic sheet metals...

The interaction between ultrasonic waves and biological tissues is the cause of cavitation phenomena. A primary scope of this paper was to set-up a measurement system for the generation of cavitation by means of forcing a low frequency (20 kHz). From the spectra and power density was evident the presence of the random component associated to the noise of cavitation was evident. For the estimate...

Cavitation cluster dynamics after the passage of a single pressure wave is studied for different concentrations of artificial cavitation nuclei (30 to 3x10(5) nuclei/ml). With increasing concentration of cavitation nuclei the lifetime of the cavitation cluster is prolonged. Additionally, it is found that the spatial extent of the cluster decreases with higher nuclei concentration. The experimen...

Cavitation appears to contribute to tissue injury in lithotripsy. Reports have shown that increasing pulse repetition frequency [(PRF) 0.5-100 Hz] increases tissue damage and increasing static pressure (1-3 bar) reduces cell damage without decreasing stone comminution. Our hypothesis is that overpressure or slow PRF causes unstabilized bubbles produced by one shock pulse to dissolve before they...