Properties of the acoustic unit.

*The intensity ranges from 0.1–2 W/cm2 at an increment of 0.1 W/cm2.†The output intensity measured by an ultrasound power meter (UPM-DT-10E, Ohmic Instrument Co., Easton, MD) from the transducer surface and divided by the effective surface area of the transducer. Attenuation due to the culture dish was practically negligible (‡The output pressure calculated from the equation I = P2/ρc, where (I) is the intensity [W/m2], (P) is the acoustic pressure, (ρ) is the density of the medium and (c) is the speed of sound in the medium.§The intensity used in sonication experiments.