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  • 1
    Electronic Resource
    Electronic Resource
    A semiclassical theory for nerve excitation by a low intensity electromagnetic field (1973)
    Springer
    Bulletin of mathematical biology 35 (1973), S. 591-605 
    Details
    ISSN: 1522-9602
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract A possible mechanism for microwave-neuron interaction, when the nerve is irradiated by a thermally insignificant electromagnetic field, is described. The radiation field is treated classically, but the atomic system which interacts with this field is treated quantum mechanically using the density matrix approach. Attention is given to both homogeneous and inhomogeneous broadening effects, and the degrading influence of inhomogeneous broadening upon the neural membrane's ability to interact with the electromagnetic field is shown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02458364
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Internal field strength measurements in chick forebrains at 50, 147, and 450 MHz. This paper has been reviewed by the Health Effects Research Laboratory, U.S. Environmental Protection Agency, and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 5 (1984), S. 293-304 
    Details
    ISSN: 0197-8462
    Keywords: brain tissue ; radiofrequency (RF) radiation ; dosmetry ; calcium ions ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: This report describes some experimental measurements of the internal field levels induced within isolated chick-forebrains irradiated at 50, 147, and 450 MHz, under essentially the same conditions as those used in the in vitro calcium-ion efflux experiments. Ratios of incident power at 50/147 MHz and 147/450 MHz that are needed to establish the same probe output are given and comparisons made with values predicted by different spherical models. Data predicted by the layered-sphere model were found to be in close agreement with measured values for the 50/147-MHz ratio. Agreement for the 147/450-MHz ratio was poorer.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250050302
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Specific absorption rate in electrically coupled biological samples between metal plates (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 7 (1986), S. 163-176 
    Details
    ISSN: 0197-8462
    Keywords: dipole coupling ; electrical images ; low frequency ; SAR ; internal field ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The specific absorption rate (SAR) in a biological sample irradiated by electromagnetic fields between the metal plates of a transmission line can be altered significantly by the spacing of the metal plates and the distance between neighboring samples. The SAR in spherical biological samples is calculated for a number of neighboring sample arrangements and metal-plate spacings by using the method of images and induced dipole coupling. For a decrease in metal-plate spacing, the derived equations predict an increase in SAR within a sample and a decrease in SAR with a decrease in neighboring-sample spacing. The calculations are compared with measurements made with the aid of an array of 1-in radius metal hemispheres on the lower plate of two parallel plates (thus forming an image system). The hemisphere on which measurements are taken is insulated from the metal plate and is connected via a coaxial center conductor to an HP 3582A spectrum analyzer that measures the voltage and hence the electric field intensity at the hemisphere. Measurements made at a frequency where wavelength is large compared with sample size (48 Hz) are in good agreement with calculations.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250070207
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  • 4
    Electronic Resource
    Electronic Resource
    Brain temperature measurements in rats: A comparison of microwave and ambient temperature exposures (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 7 (1986), S. 243-258 
    Details
    ISSN: 0197-8462
    Keywords: microwave ; 2450 MHz ; brain temperature ; rat ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: In an effort to understand microwave heating better, regional brain and core temperatures of rats exposed to microwave radiation (2450 MHz) or elevated air temperatures were measured in two studies. In general, we have found no substantial evidence for temperature differentials, or “hot spots,” in the brain of these animals. In the first study, after a 30-min exposure, no temperature differences between brain regions either after microwave or ambient air exposure were found. However, a highly significant correlation between brain and core temperatures was found and this correlation was the same for both microwave and ambient air heating. In the second study, time-temperature profiles were measured in rats exposed to either 30 mW/cm2 or 36.2°C. In this study, the 30-min exposure period was divided into seven intervals and the change in temperature during each period was analyzed. Only the cortex showed significantly different heating rates between the air heating and microwave heating; however, this difference disappeared after the initial 5 min of exposure.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250070302
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of ambient levels of power-line-frequency electric fields on a developing vertebrate (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 9 (1988), S. 129-140 
    Details
    ISSN: 0197-8462
    Keywords: ELF fields ; calcium ions ; electromagnetic fields ; brain tissue ; developing organism ; chicken ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Fertilized eggs of Gallus domesticus were exposed continuously during their 21-day incubation period to either 50- or 60-Hz sinusoidal electric fields at an average intensity of 10 Vrms/m. The exposure apparatus was housed in an environmental room maintained at 37°C and 55-60% relative humidity (RH). Within 1.5 days after hatching, the chickens were removed from the apparatus and tested. The test consisted of examining the effect of 50- or 60-Hz electromagnetic fields at 15.9 Vrms/m and 73 nTrms (in a local geomagnetic field of 38 μT, 85°N) on efflux of calcium ions from the chicken brain. For eggs exposed to 60-Hz electric fields during incubation, the chicken brains demonstrated a significant response to 50-Hz fields but not to 60-Hz fields, in agreement with the results from commercially incubated eggs [Blackman et al., 1985a]. In contrast, the brains from chicks exposed during incubation to 50-Hz fields were not affected by either 50- or 60-Hz fields. These results demonstrate that exposure of a developing organism to ambient power-line-frequency electric fields at levels typically found inside buildings can alter the response of brain tissue to field-induced calcium-ion efflux. The physiological significance of this finding has yet to be established.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250090204
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  • 6
    Electronic Resource
    Electronic Resource
    Off-center spherical model for dosimetry calculations in chick brain tissue (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 7 (1986), S. 209-221 
    Details
    ISSN: 0197-8462
    Keywords: brain tissue ; radiofrequency ; radiation ; dosimetry ; calcium ions ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: This paper presents calculations for the electric field and absorbed power density distribution in chick brain tissue inside a test tube, using an off-center spherical model. It is shown that the off-center spherical model overcomes many of the limitations of the concentric spherical model, and permits a more realistic modeling of the brain tissue as it sits in the bottom of the test tube surrounded by buffer solution. The effect of the unequal amount of buffer solution above the upper and below the lower surfaces of the brain is analyzed. The field distribution is obtained in terms of a rapidly converging series of zonal harmonics. A method that permits the expansion of spherical harmonics about an off-center origin in terms of spherical harmonics at the origin is developed to calculate in closed form the electric field distribution. Numerical results are presented for the absorbed power density distribution at a carrier frequency of 147 MHz. It is shown that the absorbed power density increases toward the bottom of the brain surface. Scaling relations are developed by keeping the electric field intensity in the brain tissue the same at two different frequencies. Scaling relations inside, as well as outside, the brain surface are given. The scaling relation distribution is calculated as a function of position, and compared to the scaling relations obtained in the concentric spherical model. It is shown that the off-center spherical model yields scaling ratios in the brain tissue that lie between the extreme values predicted by the concentric and isolated spherical models.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250070210
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    Paper (German National Licenses)
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