Record Display for the EPA National Library Catalog

RECORD NUMBER: 430 OF 2885

OLS Field Name OLS Field Data
Main Title Broadening of the RF Power-Density Window for Calcium-Ion Efflux from Brain Tissue.
Author Joines, William T. ; Blackman, Carl F. ; Hollis, Mark A. ;
CORP Author Health Effects Research Lab., Research Triangle Park, NC. Experimental Biology Div.
Year Published 1981
Report Number EPA-600/J-81/509;
Stock Number PB82-153792
Additional Subjects Calcium ; Brain ; Radiation effects ; Chickens ; Physiological effects ; Reprints ;
Holdings
Library Call Number Additional Info Location Last
Modified
Checkout
Status
NTIS  PB82-153792 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 06/23/1988
Collation 10p
Abstract
Blackman et al. have reported enhanced efflux of calcium ions from chicken forebrains, exposed in vitro in a 50 ohms stripline to 147 MHz radiation, modulated sinusoidally at 16 Hz. When the spacing between the sample tubes was 3.8 cm on center, enhancement occurred at an incident power density of 0.83 mW/sq cm, but not at 0.11, 0.55, 1.11, or 1.38 mW/sq cm. When the spacing between sample tubes was reduced to 1.9 cm, significant enhanced efflux was observed at incident power densities of 0.55, 0.83, 1.11, and 1.38 mW/sq cm. This broadening of the effective power-density range is explained herein by calculations which show that the more closely spaced samples interact electrically in a way that both lowers and broadens the range of spatial variation of absorbed power density (microwatts/cu cm) within the sample for a given incident power density (mW/sq cm). Electrical coupling among the samples allows several different values of incident power to yield exactly the same value of power absorbed at given points within the brain sample. Because the absorbed power density must be directly related to the power that interacts with the brain to enhance the efflux of calcium ions, the electromagnetic conditions for efflux enhancement in coupled and uncoupled brains are the same if the absorbed power density is the same. Ranges of absorbed power density are identified that could be effective in enhancing the efflux of calcium ions from brain tissue.