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MULTIPLE POWER DENSITY WINDOWS AND THEIR POSSIBLE ORIGIN
Citation:
Blackman, C., L. Kinney, D. House, AND W. Joines. MULTIPLE POWER DENSITY WINDOWS AND THEIR POSSIBLE ORIGIN. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-89/461 (NTIS PB91109520), 1989.
Description:
We have previously reported that in vitro exposure of chick forebrain tissue to 50-Mz radiofrequency (RF) radiation, amplitude modulated (AM) at 16 Hz, would enhance the efflux of calcium ions only within two power density ranges: one spanning from 1.44 to 1.67 mW/cm2, and the other including 3.64 mW/cm2. o-effect results occurred at 0.37, 0.72, 2.17 and 4.32 mW/cm2. e replicated and extended these results by testing another set of power densities, which included the range of this previous study. orebrain tissue from 1-7 day-old chickens were labeled in vitro with radioactive calcium ions (30 min, at 37 degrees C), rinsed, placed in a physiological salt solution and exposed for 20 min to 50-MHz radiation, AM at 16 Hz, in a TEM cell maintained at 37 degrees C. he solution was then assayed for radioactive calcium activity. ower density series was tested. nhanced efflux of calcium ions was found at 1.75,3.85,5.57,6.82, 7.65, 7.77, and 8.82 mW/cm2; no change was observed at 0.75, 2.30, 4.50, 5.85, 7.08, 8.19, 8.66, 10.6, and 14.7 mW/cm2. ower density is converted to specific absorption rate by 0.36 mW/kg/mW/cm2; a value much too low for generalized heating of the sample to be the underlying cause of this response. ypothetical mechanism is proposed involving dynamical systems that may account for the power density dependency as well as for part of the frequency dependency observed for both modulated RF radiation and for ELF fields.