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  • Occupational Health and Environmental Toxicology  (223)
  • Wiley-Blackwell  (223)
  • 2010-2014
  • 1980-1984  (223)
  • 1925-1929
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  • Wiley-Blackwell  (223)
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 1 (1980), S. 89-99 
    ISSN: 0197-8462
    Keywords: repeated acquisition ; microwave radiation ; lever press ; rats ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The acute effects of microwave exposure on a repeated acquisition baseline were investigated in three rats. Each session the animals acquired a different four-member response sequence. Each of the first three correct responses advanced the sequence to the next member, and the fourth correct response produced food reinforcement. Incorrect responses produced a three-second timeout. Baseline and control sessions were characterized by a decrease in errors within each session. The animals were acutely exposed to a 2.8 GHz pulsed-microwave field prior to test sessions, with average power densities ranging from 0.25 to 10 mW/cm2. In comparison to control sessions, 1/2 hour of exposure to microwave radiation at power densities of 5 and 10 mW/cm2 increased errors and altered the pattern of within-session acquisition. Exposure to the 10 mW/cm2 power density decreased the rate of sequence completion in all animals. The results of exposures at 0.25, 0.5, and 1 mW/cm2 power densities were generally within the control range. The results are interpreted as indicating a disruption in the discriminative stimulus control of the repeated acquisition behavior.
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  • 2
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    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 1 (1980), S. 65-76 
    ISSN: 0197-8462
    Keywords: mutagenesis ; reproduction ; rats ; 2,450 MHz ; microwaves ; continuous wave (CW) ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Tests of mutagenesis and reproduction were conducted in male rats which were irradiated by 2,450-MHz, continuous-wave (CW) microwaves, 4 hr/day from day 6 of gestation to 90 days of age at 5 mW/cm2; or 5 hr/day for five days beginning on the 90th day of age at 10 mW/cm2; or 4 hr/day, 5 days/ wk for four weeks, beginning on the 90th day of age. During selected weekly periods after treatment, the rats were bred to pairs of untreated, normal female rats that were examined in late pregnancy by means of the dominant lethal assay. The reproductive efficiency of these males, as reflected in their breeding, was also examined for changes relating to their microwave experience. No significant evidence of germ-cell mutagenesis was detected when data of microwave-exposed males were compared with those of sham-exposed males, even though there were significant increases in rectal and intra-testicular temperatures at a power density of 28 mW/cm2. Temporary sterility, as indexed by fewer pregnancies, was seen at the highest power density.
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  • 3
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    Bioelectromagnetics 1 (1980), S. 101-115 
    ISSN: 0197-8462
    Keywords: escape ; microwaves ; rats ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Ocularly pigmented rats, all mature females of the Long-Evans strain, were repeatedly presented an opportunity to escape from an intense 918-MHz field (whole-body dose rate = 60 mW/g) to a field of lower intensity (40, 30, 20, or 2 mW/g) by performing a simple locomotor response. Other rats could escape 800-μA faradic shock to the feet and tail by performing the same response in the same milieu, a multimode cavity. None of 20 irradiated rats learned to associate entry into a visually well-demarcated area of the cavity with immediate reduction of dose rate, in spite of field-induced elevations of body temperature to levels that exceeded 41°C and would have been lethal but for a limit on durations of irradiation. In contrast, all of ten rats motivated by faradic shock rapidly learned to escape. The failure of escape learning by irradiated animals probably arose from deficiencies of motivation and, especially, sensory feedback. Whole-body hyperthermia induced by a multipath field may lack the painful or directional sensory properties that optimally promote the motive to escape. Moreover, a decline of body temperature after an escape-response-contingent reduction of field strength will be relatively slow because of the large thermal time constants of mammalian tissues. Without timely sensory feedback, which is an essential element of negative reinforcement, stimulus-response associability would be imparied, which could retard or preclude learning of an escape response.
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  • 4
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    Bioelectromagnetics 2 (1981), S. 411-413 
    ISSN: 0197-8462
    Keywords: calcium efflux ; complex permittivity ; amplitude windows ; concentric spheres ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Presented here are the numerical relationships between incident power densities that produce the same average electric field intensity within a chick brain half immersed in buffered saline solution and exposed to a uniform electromagnetic field at carrier frequencies of 50, 147, and 450 MHz. Calculations are based on modeling the buffer solution as a spherical shell in air with an inner concentric sphere of brain tissue. The results support our earlier conclusion that calcium efflux results obtained at different carrier frequencies are in agreement when related by the electric field within the brain.
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  • 5
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    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 3 (1982), S. 9-16 
    ISSN: 0197-8462
    Keywords: vibrational emissivity ; nonequilibrium systems ; vibrational spectroscopy ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: An analysis of the boson (phonon and photon) distribution in the presence of a steady-state, nonequilibrium molecular subsystem is presented, providing thermodynamic criteria for the boson chemical-potential term, the generalized vibrational emissivity function, and the Bose type of condensation predicted by Fröhlich.
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  • 6
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    Bioelectromagnetics 3 (1982), S. 45-46 
    ISSN: 0197-8462
    Keywords: Non-thermal biological effects ; electric fields ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A discussion of the general implication of the existance of non-thermal biological effects of electromagnetic fields is presented.
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  • 7
    ISSN: 0197-8462
    Keywords: electric fields ; 60 Hz ; induced current ; scaling ; SAR ; thermograph ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The thermographic method for determining specific absorption rate (SAR) in animals and models of tissues or bodies exposed to electromagnetic fields was applied to the problem of quantifying the current distribution in homogeneous bodies of arbitrary shape exposed to 60-Hz electric fields. The 60-Hz field exposures were simulated by exposing scale models of high electrical conductivity to 57.3-MHz VHF fields of high strength in a large 3.66 × 3.66 × 2.44-m TE101 mode resonant cavity. After exposure periods of 2-30 s, the models were quickly disassembled so that the temperature distribution (maximum value up to 7 °C) along internal cross-sectional planes of the model could be recorded thermographically. The SAR, W′, calculated from the temperature changes at any point in the scale model was used to determine the SAR, W, for a full-scale model exposed to a 60-Hz electric field of the same strength by the relation W = (60/ f2 · (σ′/σ) · W′ where f′ is the model exposure frequency, σ′ is the conductivity of the scale model at the VHF exposure frequency, and σ is the conductivity of the full-scale subject at 60 Hz. The SAR was used to calculate either the electric field strength or the current density for the full-scale subject. The models were used to simulate the exposure of the full-scale subject located either in free space or in contact with a conducting ground plane. Measurements made on a number of spheroidal models with axial ratios from 1 to 10 and conductivity from 1 to 10 s/m agreed well with theoretical predictions. Maximum current densities of 200 nA/cm2 predicted in the ankles of man models and 50 nA/cm2 predicted in the legs of pig models exposed to 60-Hz fields at 1kV/m agreed well with independent measurements on full-scale models.
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  • 8
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    Bioelectromagnetics 3 (1982), S. 105-116 
    ISSN: 0197-8462
    Keywords: escape ; microwaves ; rats ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A total of 16 female hooded rats was first observed for baseline behaviors and then they received 25 2-min trials of training, five trials per day, under one of four stimulus conditions (all ns = 4): exposure to a highly intense 918-MHz field (dose rate, 60 mW/g); exposure to photic stimulation (≈350 Ix); exposure to the field in synchrony with photic stimulation; or exposure to faradic shock (≈800 μA rms). During conditioning trials, which were separated by 2-min intertrial intervals, entry by a rat into a safe area of a multimode cavity resulted in immediate and complete cessation of stimulation; exit, in resumption. Acquisition of the escape response was rapid and highly efficient for shocked animals and was less rapid and efficient but was reliably demonstrated by irradiated animals that were also signaled by light. In the absence of microwave irradiation, cessation of light did not reliably motivate escape behavior. Although there was weak evidence of escape learning by rats subjected only to microwave irradiation, their performances failed to differ reliably from those of rats in the light-only condition. These data confirm and extend those of Carroll et al, which indicate that potentially lethal, deeply penetrating, nonpulsed microwaves in a multipath field lack the sensory quality to motivate efficient aversive behavior by the rat.
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  • 9
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    Bioelectromagnetics 3 (1982), S. 127-132 
    ISSN: 0197-8462
    Keywords: cardiac muscle ; electric properties ; syncytium ; cable theory ; cell membrane ; intracellular potential ; extracellular potential ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A model of electrical activity in the heart has been developed that treats the intracellular domain and the extracellular domain as electrical syncytia with anisotropic resistivities (bi-syncytial model). At the microscopic level, propagation is assumed to proceed primarily along the axes of individual cells. Considerations at the macroscopic level relate the transmembrane current to the intracellular and extracellular resistivity and the transmembrane potential. The result is a relationship between instantaneous extracellular potentials and cardiac action potentials.
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  • 10
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    Bioelectromagnetics 3 (1982), S. 147-156 
    ISSN: 0197-8462
    Keywords: pulsed ultrasound ; biological ultrasound ; Drosophilia ; Elodea ; cavitation ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Studies with both plant and animal tissues show that, when the tissues contain micron-sized, stabilized gas bodies, pulsed ultrasound can produce damage at very low time-averaged intensities. However, it is the temporal peak intensity rather than the time-averaged intensity that is closely correlated with the effects observed. The data suggest that there may be thresholds for damage at peak intensities within an order of magnitude of 10 W/cm2.
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  • 11
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    Bioelectromagnetics 3 (1982), S. 157-165 
    ISSN: 0197-8462
    Keywords: ultrasonic absorption ; proteins ; polypeptides ; peptides ; amino acids ; tissues ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: This article reviews significant advances in understanding the basis for the magnitude of ultrasonic absorption in proteins and related biological materials. Carstensen and Schwan's accurate and extensive measurements on blood and hemoglobin solutions provided the initial experimental data; these were augmented by data from measurements on aqueous solutions of gelatin, bovine serum albumin, lysozyme, various polypeptides, and amino acids. The initial frequency range of 1-10 MHz; was expanded to 0.035-1000 MHz; temperature and pH dependences of absorption were studied. Theoretical approaches included consideration of the relative motion of blood cells in plasma, perturbation of water structure around macromolecules, solvation of charged entities, proton-transfer reactions, and helix-coil transitions.Proton-transfer reactions between amino and carboxylic groups and water proved to be largely responsible for the observed peaks in the pH dependence of absorption coefficient; the peaks occurred in the basic and acidic regions corresponding to the pKs for titration of these groups. Such reactions could not account for the magnitude of absorption at physiological pH because only histidine titrated in this range. Extensive analysis, using relaxation theory, and, measurements have shown that the proton transfer reaction between the imidazole group of histidine and hydrogen phosphate ion (in solution) provides sufficient volume change for significant ultrasonic absorption at physiological pH. Excellent agreement between theory and experiment was found with the peptide bacitracin in phosphate buffer solutions. By generalizing these results to the case of a protein, Slutsky et al estimated maximum values of frequency-dependent absorption coefficients for “typical tissue” and found them to be correct to order of magnitude, even exceeding observed values in soft tissues in some instances, instead of being far too small as was always the case in the past. Thus, in principle, adjustment of parameters, such as pK values, could bring theory and experiment into agreement for the first time.
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  • 12
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    Bioelectromagnetics 3 (1982), S. 203-212 
    ISSN: 0197-8462
    Keywords: S-band microwaves ; modulation ; action potential ; resting potential ; Chara corallina ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Single internodal excitable cells of Chara corallina were exposed to CW, pulse-modulated and sinusoidally modulated S-band microwave fields in a temperature-controled waveguide exposure chamber. All electrical measurements were made external to the waveguide (ie, under no impressed microwave field). The dependent variables measured before, during, and after exposure to the S-band microwave fields included: resting potential, amplitude of the action potential, rise and decay time of the action potential, conduction velocity, and excitability. Cells maintained at 22 ± 0.1 °C during exposure showed no consistent or statistically significant microwave-dependent alterations in any of the dependent variables.
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  • 13
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    Bioelectromagnetics 3 (1982), S. 247-251 
    ISSN: 0197-8462
    Keywords: ultrasound ; temperature-dependent cell killing ; membrane fluidity ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Chinese hamster cells in suspension were exposed to 20 kHz ultrasound (US) at 54 W/cm2 and various temperatures between 2 and 44 °C. Activation energies were 2.6 and 24 kcal/mole below and above 35 °C, respectively. Procaine, a local anaesthetic drug known to increase membrane fluidity, enhanced cellular inactivation by US above 41 °C, increasing the activation energy to 62 kcal/mole. The inactivation of the bacterium Salmonella typhimurium by US was also dependent on the exposure temperature, with an activation energy of 2.9 kcal/mole between 2 and 44 °C. These data are most simply explained by the hypothesis that membranes are a major target for cellular inactivation by US and that the fluidity of the membranes is important in this respect.
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  • 14
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    Bioelectromagnetics 3 (1982), S. 253-274 
    ISSN: 0197-8462
    Keywords: radiofrequency ; nearfield ; hyperthermia ; dosimetry ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A homogeneous, lossy circular cylinder is used as a simple model of a biological object in which interior heating is produced by the absorption of electromagnetic waves. For this model, we determined the optimum frequency, polarization, orientation and shape of applicators. Analytical and numerical results are given for both electric and magnetic line sources, with three different polarizations relative to the cylinder. Coupling efficiencies and contour plots are presented for a range of parameters. One particularly interesting result is the production of maximum energy deposition at the center of a cylinder of muscle tissue when exposed in the 100-MHz frequency range by the use of four applicators surrounding the cylinder.
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  • 15
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    Bioelectromagnetics 2 (1981), S. 23-32 
    ISSN: 0197-8462
    Keywords: biological effects of oscillating electric fields ; excitable cells ; voltage-sensitive ion channels ; gating charges ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: An alternating component of potential across the membrane of an excitable cell may change the membrane conductance by interacting with the voltagesensing charged groups of the protein macromolecules that form voltage-sensitive ion channels. Because the probability that a voltage sensor is in a given state is a highly nonlinear function of the applied electric field, the average occupancy of a particular state will change in an oscillating electric field of sufficient magnitude. This “rectification” at the level of the voltage sensors could result in conformational changes (gating) that would modify channel conductance. A simplified two-state model is examined where the relaxation time of the voltage sensor is assumed to be considerably faster than the fastest changes of ionic conductance. Significant changes in the occupancy of voltage sensor states in response to an applied oscillating electric field are predicted by the model.
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  • 16
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    Bioelectromagnetics 3 (1982), S. 323-332 
    ISSN: 0197-8462
    Keywords: diphenylhexatriene ; fluorescence depolarization ; microviscosity ; multilamellar phospholipid vesicles ; phase transition ; 1-GHz microwave radiation ; TEM cell ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The phase transition in multilamellar dimyristoylphosphatidylcholine (DMPC) vesicles was studied during exposure to continuous wave 1.0-GHz microwave radiation. Fluorescence depolarization measurements using a lipid-seeking molecular probe, diphenylhexatriene (DPH). were performed as a function of temperature. Semilog plots of microviscosity versus temperature illustrate the phase transition which shows a 5°C shift when the vesicles are treated with chloroform as a positive control. No shift of the phase transition was found during exposure to microwave radiation at specific absorption rates between 1 and 30 W/kg. Samples were exposed in a rectangular transmission line (TEM cell), and specific absorption rates were calculated from electrical measurements of incident, reflected, and transmitted power. Samples were exposed to increasing intensities of radiation, while the temperature was maintained at either 23.5 or 25.5 °C; these temperatures represented the two ends of the phase transition region for these vesicles. No statistically significant difference was found between exposed and control samples. These results are in contrast to those of others using laser Raman spectroscopy to measure the phase transition in similar multilamellar vesicles exposed to microwave radiation.
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  • 17
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    Bioelectromagnetics 2 (1981), S. 71-75 
    ISSN: 0197-8462
    Keywords: honeybees ; invertebrates ; behavior ; solar power satellite ; 2.45-GHz microwaves ; continuous wave ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Foraging-experienced honeybees retained normal flight, orientation, and memory functions after 30 minutes' exposure to 2.45-GHz CW microwaves at power densities from 3 to 50 mW/cm2. These experiments were conducted at power densities approximating and exceeding those that would be present above receiving antennas of the proposed solar power satellite (SPS) energy transmission system and for a duration exceeding that which honeybees living outside a rectenna might be expected to spend within the rectenna on individual foraging trips. There was no evidence that airborne invertebrates would be significantly affected during transient passage through microwaves associated with SPS ground-based microwave receiving stations.
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  • 18
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    Bioelectromagnetics 3 (1982), S. 413-420 
    ISSN: 0197-8462
    Keywords: honeybee ; olfaction ; electrostatics ; electret ; chemosensillae ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Pore plates (placoid chemosensillae) on the antennae of dead worker honeybees (Apis mellifera L.) apparently retained a static electric charge that was significantly different from that of the surrounding cuticle. Residual charge resulted in the concentration of airborne particulate matter over the rim of exposed pore plates to the virtual exclusion of such deposition on surrounding cuticle. Postmortem integrity of polar lipids associated with the pore plate and adjacent sense cells is hypothesized as the source of the static potential. Such a lipoidal matrix, if functioning as an electret and if attracting odorous molecules to receptor cells from outside the odor stream of individual receptors, would greatly enhance receptor efficiency of living bees.
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  • 19
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    Bioelectromagnetics 2 (1981), S. 93-103 
    ISSN: 0197-8462
    Keywords: permittivity ; in vivo ; radio frequencies ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: An open-ended coaxial line sensor in conjunction with an automatic network analyzer was used to measure in vivo the permittivity of several feline tissues (skeletal and smooth muscle, liver, kidney, spleen, and brain - gray and white matter) at frequencies between 10 MHz and 1 GHz. The estimated uncertainties of measurement were between 1.5% and 5%. The data are in general agreement with previously obtained data in vitro and in vivo. Significant differences in the properties of different types of the same tissue (eg, skeletal and smooth muscle) were observed. Many tissues were found to be non-homogeneous in its permittivity.
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  • 20
    ISSN: 0197-8462
    Keywords: millimeter-wave radiation ; BHK-21/C13 cells in monolayer culture ; scanning electron microscopy ; transmission electron microscopy ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Both thermal and athermal effects of millimeter-wave radiation on BHK-21/C13 cells were sought using scanning and transmission electron microscopy in conjunction with an in vitro technique that allows direct exposure of monolayer cultures to high average power densities. Culture dishes were irradiated by placing them on the open end of an E- or U-band wave guide. This technique exposes different regions of the cell monolayer lying along the longer axis of the wave guide aperture to varying power densities ranging from zero at each edge to twice the average power density at the center.Cell ultrastructure was unaffected by microwave radiation for 1 hour (41.8 or 74.0 GHz, average power densitites = 320 or 450 mW/cm2, respectively) with or without cooling by rapid recirculation of the culture medium. Temperature in recirculated cultures was held at 37.2 °C, and that in noncooled cultures never exceeded 42 °C during irradiation at either power density. In contrast, cell morphology was affected by microwave exposure whenever irradiation conditions were altered so that the temperature of the monolayer reached or exceeded 44.5 °C. Ultrastructural alterations included breakage of cell processes, progressive detachment of cells from the substrate, increased clumping of heterochromatin in the nuclei, and the appearance of large empty vesicles in the cytoplasm. Such morphological changes resulted from either application of higher average power densities or irradiation at the power densities described above at a higher ambient temperature (〉38.5°C).
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  • 21
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    Bioelectromagnetics 2 (1981), S. 187-198 
    ISSN: 0197-8462
    Keywords: ciliated protozoan ; DC magnetic field ; calcium-mediated contraction ; motility ; 2,2′-dipyridyldisulfide ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Effects of DC magnetic fields, up to 125,000 G, on the survival of the ciliated protozoan Spirostomum ambiguum exposed to the toxic substance 2,2′-dipyridyldisulfide are reported. The magnetic field diminishes the ability of the organism to survive the drug, and lengthens the extension phase of the contraction cycle. It is proposed that the magnetic field alters the regulation of intracellular (C2+) transients.
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  • 22
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    Bioelectromagnetics 2 (1981), S. 199-201 
    ISSN: 0197-8462
    Keywords: static magnetic fields ; development ; frog embryos ; low temperature ; cell membranes ; lipid phase transition ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Xenopus laevis embryos were exposed to a DC magnetic field (2.5 kG) for periods up to 1 week. The previously reported stabilization of cell membranes by stationary magnetic fields could not be demonstrated.
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  • 23
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    Bioelectromagnetics 2 (1981), S. 407-409 
    ISSN: 0197-8462
    Keywords: calcium efflux ; complex permittivity ; amplitude windows ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The recent suggestion that the pattern of positive and negative results of RF-induced calcium efflux from chick brain tissue, when appropriately scaled, matches at three frequencies is examined. Close scrutiny of this recently reported analysis by Joines and Blackman suggests that the uncertainties in the calculated scaling quantities are too large to permit meaningful conclusions.
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  • 24
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    Bioelectromagnetics 3 (1982) 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
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  • 25
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    Bioelectromagnetics 3 (1982), S. 1-2 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
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  • 26
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    Bioelectromagnetics 2 (1981), S. 247-257 
    ISSN: 0197-8462
    Keywords: nervous system ; rat cerebellum ; nonionizing radiation ; Purkinje cells ; microwaves ; radiofrequency ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: In one experiment, Sprague Dawley rats (16-21 days of gestation) and their offspring were exposed to 100-MHz (CW) electromagnetic radiation at 46 mW/cm2 (SAR 2.77 mW/g) for 4 h/day for 97 days. In another experiment, the pregnant rats were irradiated daily from 17 to 21 days of gestation with 2450-MHz (CW) microwaves at 10 mW/cm2 (SAR 2 mW/g) for 21 h/day. In a third experiment, 6-day-old rat pups were irradiated 7 h/day for five days with 2450-MHz radiation at 10 mW/cm2. Equal numbers of animals were sham irradiated in each group. Quantitative studies of Purkinje cells showed a significant and irreversible decrease in rats irradiated during fetal or fetal and early postnatal life. In animals exposed postnatally, and euthanized immediately after irradiation, significant decrease in the relative number of Purkinje cells was apparent. However, restoration apparently occurred after forty days of recovery.
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  • 27
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    Bioelectromagnetics 4 (1983), S. 123-139 
    ISSN: 0197-8462
    Keywords: microwave immunosuppression ; natural killer cells ; hamster immune system ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Hamsters were exposed to repeated or single doses of microwave energy and monitored for changes in core body temperature. circulating leukocyte profiles, serum corticosteroid levels, and natural killer (NK) cell activity in various tissues. NK cytotoxicity was measured in a 15Crrelease assay employing baby hamster kidney (BHK) targets or BHK infected with herpes simplex virus. Repeated exposure of hamsters at 15 mW/cm2 for 60 min/day had no significant effect on natural levels of spleen-cell NK activity against BHK targets. Similarly, repeated exposure at 15 mW/cm2 over a 5-day period had no demonstrable effect on the induction of spleen NK activity by vaccinia virus immunization, that is. comparable levels of NK were induced in untreated and microwave-treated animals. In contrast, treatment of hamsters with a single 60-min microwave exposure at 25 mW/cm2 caused a significant suppression in induced spleen NK activity. A similar but less marked decrease in spleen NK activity was observed in sham-exposed animals. Moreover, the sham effects on NK activity were not predictable and appeared to represent large individual animal variations in the response to stress factors. Depressed spleen NK activity was evident as early as 4 h postmicrowave treatment and returned to normal levels by 8 h. Hamsters exposed at 25 mW/cm2 showed an elevated temperature of 3.0-3.5 °C that returned to normal within 60 min after termination of microwave exposure. These animals also showed a marked lymphopenia and neutrophilia by 1 h posttreatment that returned to normal by 8-10 h. Serum glucocorticosteroids were elevated between 1 and 8 h after microwave treatment. Sham-exposed animals did not demonstrate significant changes in core body temperature. peripheral blood leukocyte (PBL) profile, or glucocorticosteroid levels as compared to minimum-handling controls.
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  • 28
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    Bioelectromagnetics 3 (1982), S. 29-43 
    ISSN: 0197-8462
    Keywords: dielectric properties ; permittivity ; conductivity ; microemulsions ; water of hydration ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: We summarize the results of several of our recent studies on the dielectric properties of protein solutions, tissues, and nonionic microemulsions at microwave frequencies extending to 18 GHz. The data in all cases are analyzed using the Maxwell mixture theory to determine the dielectric properties of the suspending water and the amount and dielectric properties of the water of hydration associated with the suspended phase. The dielectric data from the protein solutions and tissues are broadly consistent with the results of previous studies at UHF frequencies; they indicate hydration values in the range of 0.4-0.6 g water/g protein. There is evidence of a dielectric relaxation process occurring at low-GHz frequencies that can be attributed in part to dielectric relaxation of the “bound” water in the system. The remaining solvent water appears to have dielectric properties close to, if not precisely the same as, those of pure water. The average relaxation frequency of the suspending water in the microemulsions is reduced from that of pure water, evidently reflecting an average of that of the water of hydration (∼5-6 GHz) and that of pure water. This reduced average relaxation frequency implies an increased average viscosity of the water and (by Walden's rule) accounts for the unexpectedly low ionic conductivity of the preparations.
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    Bioelectromagnetics 3 (1982), S. 117-125 
    ISSN: 0197-8462
    Keywords: microwaves ; infrared ; human ; thresholds ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Three male and three female adults individually placed the ventral surface of the right and upright forearm against a 15-cm-diameter aperture in a wall of microwave-absorbent material. Tensecond exposures occurred to E-vector-vertically polarized, 2450-MHz-CW microwave (MW) fields. Comparable exposure to infrared (IR) waves was repeated with four of the six observers. Thresholds of detection of just-noticeable warming by MW and IR radiation were determined by the double-staircase psychophysical method. Although the exposed surface areas of male observers' arm were larger than those of female observers, thresholds of warming by either source of energy overlapped; the pooled means of irradiance at threshold are 26.7 mW/cm2 (MW) and 1.7 mW/cm2 (IR). Dosimetric measures on saline models indicated virtually perfect absorption of the incident IR, but nearly two-thirds of the MW energy was scattered. Accordingly, the 15-fold difference in means of MW and IR thresholds resolves to a 5-fold difference in threshold quantities of absorbed energy. In the light of the high correlation between thresholds of IR and MW irradiation (r = .97), it is concluded that the same set of superficial thermoreceptors was being stimulated, only less efficiently so, by the more deeply penetrating, more diffusely absorbed MW energy.
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  • 30
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    Bioelectromagnetics 3 (1982) 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
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  • 31
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    Bioelectromagnetics 3 (1982), S. 193-201 
    ISSN: 0197-8462
    Keywords: characean cells ; thermal response ; electromagnetic bioeffects ; real time measurement ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A giant cell (circa 10 mm long) of Chara braunii or Nitella flexilis was placed in a microstrip exposure apparatus, and the vacuolar potential at one end was monitored with a micropipette while the other end was exposed to pulses of VHF radiation at electric field strengths up to 6250 V/m. With suitable filtering and signal averaging, offsets of the vacuolar potential could be detected in real time and at levels as low as 1 μU V. The only effect that has been reproducibly observed in the carrier frequency range 20-300 MHz was the slow ramp-like hyperpolarization previously reported [Pickard and Barsoum, 1981] and tentatively attributed to electromagnetic heating of the system. The slopes of these ramps became more pronounced with increasing frequency and behaved in accordance with theoretical predictions.
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  • 32
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    Bioelectromagnetics 3 (1982), S. 213-218 
    ISSN: 0197-8462
    Keywords: leucocytes ; transient currents ; spark discharges ; biological effects ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Human leucocytes were exposed to high-voltage pulses (transient currents) produced by discharging a capacitor through a test chamber containing the cell suspension then tested for viability using trypan blue. With the pulse discharge times of 1 and 3 μs increases in the number of dyeloaded cells were seen for field strengths above 2.6 kV/cm in the sample. For 0.2-μs pulses the critical field strength was about 5 kV/cm.
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    Bioelectromagnetics 3 (1982), S. 227-235 
    ISSN: 0197-8462
    Keywords: microwaves ; pulsed-wave ; continuous-wave ; operant behavior ; DRL schedule ; rats ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The effects of pulsed-(PW) and continuous-wave (CW) 2.8-GHz microwaves were compared on the performance of rodents maintained by a temporally defined schedule of positive reinforcement. The schedule involved food-pellet reinforcement of behavior according to a differential-reinforcement-of-low-rate (DRL) contingency. The rats were independently exposed to PW and to CW fields at power densities ranging from 1 to 15 mW/cm2. Alterations of normal performance were more pronounced after a 30-minute exposure to the PW field than to the CW field. The rate of emission of appropriately timed responses declined after exposure to PW at 10 and 15 mW/cm2, whereas exposure at the same power levels to the CW field did not consistently affect the rate of responding. Change in performance associated with microwave exposure was not necessarily related to a general decline in responding: in some instances, increases in overall rates of responding were observed.
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    Bioelectromagnetics 3 (1982), S. 293-293 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
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    Bioelectromagnetics 3 (1982), S. 471-474 
    ISSN: 0197-8462
    Keywords: 8.8 GHz ; pulsed microwave ; thermal vs microwave alteration ; E coli ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Escherichia coli pol A+ and pol A- strains were exposed to 8.8-GHz microwaves pulsed at 1,000 Hz (1-μs pulse width) and an SAR of 40 W/kg, which increased the temperature of the cell culture by 7 °C. Two-way analysis of variance showed no significant difference between the growth rates of microwave irradiated and thermally exposed cells.
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    Bioelectromagnetics 4 (1983), S. 11-19 
    ISSN: 0197-8462
    Keywords: electric field ; bone growth ; osteotomy repair ; rats ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Rats were exposed to a 60-Hz electric field at an unperturbed field strength of 100 kV/m to determine its affect on bone growth and fracture repair. Exposure of immature male and female rats for 20 h/day for 30 days did not alter growth rate, cortical bone area, or medullary cavity area of the tibia. In another experiment, midfibular osteotomies were performed and the juvenile rats were exposed at 100 kV/m for 14 days. Evaluation by resistance to deformation and breaking strength indicated that fracture repair was not as advanced in the exposed animals as in the shamexposed animals. In another experiment measurements of resistance to deformation were made in adult rats at 16, 20, and 26 days after osteotmy. Fracture repair was slower in exposed compared to control animals at day 20 and, to a lesser extent, at day 16, but not at day 26.
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    Bioelectromagnetics 4 (1983), S. 55-62 
    ISSN: 0197-8462
    Keywords: 2880-MHz microwaves ; submaxillary salivary gland ; Na+ ; K+ ; Ca2+ ; flame photometry ; hyperthermia ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Na+, K+, and Ca2+ concentrations in the blood serum and submaxillary salivary gland (SSG) were investigated in adult, male rats exposed to 2880-MHz microwaves modulated with 1.5-μs pulses at a pulse repetition rate of 1000 Hz or in a hyperthermal environment. Rats were exposed, one at a time, for 30 min to microwaves producing a specific absorption rate (SAR) of: 4.2, 6.3,6.8,8.4, 10.8, or 12.6 W/kg, or were sham exposed under similar environmental conditions. In a second series, one group of rats was exposed singly for 15, 30, or 60 min to microwaves producing an SAR of 9.5 W/kg and other rats were exposed for similar periods at 40 °C; and 10 rats were sham exposed. Flame photometric analysis indicated that the thresholds of microwave radiation required to induce a change in Na+, K+, and Ca2+ concentrations in the salivary glands are 6.8, 6.8, and 6.3 W/kg, respectively. The directions of Na+, K+, and Ca2+ ion shifts in exposed rats' salivary glands are similar, whether affected by microwaves or hyperthermia. Greater changes in Na+ and K+ concentrations in SSG of rats exposed to microwaves for 15 and 30 min were found than in those exposed at 40 °C. On the other hand, exposure to hyperthermia at 40 °C or to microwaves for 1 h caused Na+ concentration to be increased by 68.7 and 59.5% and K+ concentration to be decreased by 29.6 and 21.7%, respectively.
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  • 38
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    Bioelectromagnetics 4 (1983), S. 63-77 
    ISSN: 0197-8462
    Keywords: microwaves ; exposure chamber ; dosimetry ; rabbit ; body mass ; food consumption ; blood chemistry ; pathology ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Two groups of 16 male New Zealand rabbits were exposed to 2450-MHz continuous wave microwave fields in two experiments of 90 days each. The incident power densities of the first and second experiment were 0.5 and 5 mW/cm2, respectively. During each study, 16 animals were adapted to a miniature anechoic chamber exposure system for at least 2 weeks, then 8 of them were exposed for 7 h daily, 5 days a week for 13 weeks, and the other 8 animals were sham exposed. The rabbits were placed in acrylic cages, and each was exposed from the top in an individual miniature anechoic chamber. Thermography showed a maximum specific absorption rate of 5.5 W/kg in the head and 7 W/kg in the back at 5-mW/cm2 incident power density. After each 7-h exposure session, the animals were returned to their home cages. Food consumption in the exposure chamber and body mass were measured daily. Blood samples were taken before exposure and monthly thereafter for hematological, morphological, chemical, protein electrophoresis, and lymphocyte blast transformation studies. Eyes were examined for cataract formation. Finally, pathological examinations of 28 specimens of organs and tissues of each rabbit were performed. Statistically, there was a significant (P 〈 .01) decrease only of food consumption during the 5-mW/cm2 exposure; other variables were not significantly different between exposed and control groups.
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  • 39
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    Bioelectromagnetics 4 (1983), S. 107-114 
    ISSN: 0197-8462
    Keywords: spermatogenesis ; microwave radiation ; germinal tissue ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Male Sprague-Dawley rats were exposed for 6 h per day for nine days to pulse-modulated microwave radiation (1.3 GHz, at 1-μs pulse width, 600 pulses per second). Exposures were carried out in cylindrical waveguide sections at a mean dose rate of 6.3 mW/g; sham controls were treated similarly and received no irradiation. At time periods corresponding to 0.5, 1.0, 2.0, and 4.0 cycles of the seminiferous epithelium, groups of four shamirradiated and four irradiated rats were killed and the testes removed for analysis. Net mass of the testes, epididymides, and seminal vesicles; daily sperm production (DSP) per testis and per gram of testis; sperm morphology; and the number of epididymal sperm were determined. There were no statistically significant differences between the shamirradiated and irradiated groups with respect to any measured variable. In a group of seven surrogate animals of similar body mass, the dose rate of 6.3 mW/g caused a net change in body temperature (via rectal probe) of 1.5 °C.
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    Bioelectromagnetics 4 (1983), S. 141-155 
    ISSN: 0197-8462
    Keywords: microwave bioeffects ; hamster macrophages ; immunology ; viricidal macrophages ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Acute exposure of hamsters to microwave energy (2.45 GHz; 25 mW/cm2 for 60 min) resulted in activation of peritoneal macrophages that were significantly more viricidal to vaccinia virus as compared to sham-exposed or normal (minimum-handling) controls. Macrophages from microwave-exposed hamsters became activated as early as 6 h after exposure and remained activated for up to 12 days. The activation of macrophages by microwave exposure paralleled the macrophage activation after vaccinia virus immunization. Activated macrophages from vacciniaimmunized hamsters did not differ in their viricidal activity when the hamsters were microwave or sham-exposed. Exposure for 60 min at 15 mW/cm2 did not activate the macrophages while 40 mW/cm2 exposure was harmful to some hamsters. Average maximum core temperatures in the exposed (25 mW/cm2) and sham groups were 40.5 °C (±0.35 SD) and 38.4 °C (±0.5 SD), respectively. In vitro heating of macrophages to 40.5 °C was not as effective as in vivo microwave exposure in activating macrophages to the viricidal state. Macrophages from normal, shamexposed, and microwave-exposed hamsters were not morphologically different, and they all phagocytosed India ink particles. Moreover, immune macrophage cytotoxicity for virus-infected or noninfected target cells was not suppressed in the microwave-irradiated group (25 mW/cm2, 1 h) as compared to sham-exposed controls, indicating that peritoneal macrophages were not functionally suppressed or injured by microwave hyperthermia.
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  • 41
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    Bioelectromagnetics 4 (1983) 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
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  • 42
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    Bioelectromagnetics 4 (1983), S. 205-214 
    ISSN: 0197-8462
    Keywords: microwaves ; apomorphine ; amphetamine ; morphine ; behavior ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The effects of various psychoactive drugs were studied in rats exposed for 45 min in a circularly polarized, pulsed microwave field (2450 MHz; SAR 0.6 W/kg; 2-μs pulses, 500 pps). Apomorphine-induced hypothermia and stereotypy were enhanced by irradiation. Amphetamine-induced hyperthermia was attenuated while stereotypy was unaffected. Morphine-induced catalepsy and lethality were enhanced by irradiation at certain dosages of the drug. Since these drugs have different modes of action on central neural mechanisms and the effects of microwaves depend on the particular drug studied, these results show the complex nature of the effect of microwave irradiation on brain functions.
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  • 43
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    Bioelectromagnetics 4 (1983), S. 267-279 
    ISSN: 0197-8462
    Keywords: mice ; specific absorption rate ; calorimetry ; TEM chamber ; 200-400 MHz CW ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A maximum of six live mice, mouse cadavers, prolate spheroids molded from muscle-equivalent tissue, or saline-filled culture flasks, were exposed to continuous wave radiation in a TEM cell at frequencies between 200 and 400 MHz. Whole-body average specific absorption rate (SAR) was determined from power meter measurements of incident, reflected, and transmitted powers. The SARs for both live mice and cadavers were approximately twice that for the prolate spheroid models, and when housed in Plexiglas restraining cages, about 2 1/2 times greater. An error multiplying factor is identified, that quantitatively expresses how SAR data obtained by the three -power-meter method becomes progressively more noisy as the irradiation frequency is lowered or as the TEM cell cross section is increased.
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  • 44
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    Bioelectromagnetics 4 (1983) 
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    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
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  • 45
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    Bioelectromagnetics 4 (1983), S. 295-301 
    ISSN: 0197-8462
    Keywords: fusion reactors ; magnetic fields ; biological effects ; fertilization ; fish ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The sensitivity of trout ova and sperm to 1-T magnetic fields was investigated. It was determined that (1) overall test results combining seven independent Z-statistics demonstrated a significant (α 〈 0.0001) enhancement of fertilization when ova alone were exposed to the magnetic field prior to fertilization; (2) similarly, overall test results combining Z-statistics from eight independent experiments indicated a significant (α 〈 0.0004) enhancement when sperm alone were exposed; and (3) statistical analysis of nine independent experiments confirmed enhanced fertilization (α 〈 0.0001) when both ova and sperm were exposed to the magnetic field prior to fertilization. Although these data indicated that both ova and sperm were sensitive to magnetic fields, simultaneous exposure of both gametes did not have a greater total effect on fertilization rate than the sum of their individual effects.
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    Bioelectromagnetics 4 (1983), S. 303-314 
    ISSN: 0197-8462
    Keywords: DC electric fields ; exposure systems ; finite difference method (FDM) ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: In most previous 50/60-Hz experiments, subjects were placed in a dielectric cage and the electric field was applied from outside the cage. Although the field outside the cage was kept uniform in space and constant in time, the field inside the cage undergoes undesirable temporal and spatial variations. We have designed an electric-field exposure system that overcomes these problems by having a metal cage constitute a part of the field generating electrodes. The uniformity along the diameter of the cages for mice and cats are more than 84.2% and 74.3%, respectively.
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    Bioelectromagnetics 4 (1983), S. 315-326 
    ISSN: 0197-8462
    Keywords: Drosophila ; ELF electromagnetic effects ; oviposition ; development ; viability ; magnetic fields ; DC magnetic fields ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Drosophila flies placed in a habitat with two lateral boxes demonstrated sensitivity to magnetic fields: Oviposition decreased by exposure to pulsated extremely low frequency (ELF) (100)Hz, 1.76 miliTesla (mT) and sinusosidal fields (50 Hz, 1 mT), while there was no initial effect of exposure to a static magnetic field (4.5 mT). Drosophila eggs treated for 48 h with the above described fields showed that (1) mortality of eggs was lower in controls than in eggs exposed to all tested magnetic fields; (2) mortality of larvae increased when a permanent magnet was used; (3) mortality of pupae was highest when a permanent magnet was used; and (4) general adult viability was highest in controls (67%) and diminished progressively when eggs were exposed to pulsated (55%), sinusoidal (45%), and static (35%) magnetic fields.
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    Bioelectromagnetics 4 (1983), S. 357-370 
    ISSN: 0197-8462
    Keywords: Helmholtz coils ; electromagnetic fields ; induced currents ; saline media ; biological tissue ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The use of Helmholtz aiding coils to induce small electromagnetic (EM) fields in living tissue for both medical and research purposes has become quite common. While much progress has been made in showing that these induced EM signals can cause a variety of effects in tissues and individual cells, a satisfactory explanation of how the effects occur or how the EM signals couple to the tissue has not yet emerged. To address the latter problem adequately, it becomes necessary to know the spatial distribution of the induced fields inside a given set of boundaries. This paper examines the situation used for much in vitro research where a cylindrical culture dish is filled with a conducting solution and placed between the Helmholtz coils. Two cases are considered. The first assumes that the coils are above and below the culture dish (the planes of the coils are parallel with the top and bottom of the dish); the second assumes that the planes of the coils are parallel with the sides of the dish. A closed form solution is obtained for both cases, and it is shown that the induced EM field distribution is markedly different for the two cases.
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    Bioelectromagnetics 5 (1984) 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
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    Bioelectromagnetics 5 (1984), S. 71-78 
    ISSN: 0197-8462
    Keywords: human neuroblastoma cells ; calcium ion efflux ; microwave ; amplitude modulation ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Monolayer cultures of human neuroblastoma cells were exposed to 915-MHz radiation, with or without sinusoidal amplitude modulation (80%) at 16 Hz, at specific absorption rates (SAR) for the culture medium and cells of 0.00, 0.01, 0.05, 0.075, 0.1, 0.5, 0.75, 1.0, 1.5, 2, or 5 mW/g. A significant increase in the efflux of calcium ions (45Ca2+) as compared to unexposed control cultures occurred at two SAR values: 0.05 and 1 mW/g. Increased efflux at 0.05 mW/g was dependent on the presence of amplitude modulation at 16 Hz but at the higher value it was not. These results indicate that human neuroblastoma cells are sensitive to extremely low levels of microwave radiation at certain narrow ranges of SAR.
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    Bioelectromagnetics 5 (1984), S. 147-164 
    ISSN: 0197-8462
    Keywords: DC and 60-Hz magnetic fields ; animal behavior ; memory retention ; locomotor activity ; pentylenetetrazole sezure threshold ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Behavioral measures were evaluated in adult CD-1 and LAF-1 mice continuously exposed for 72 h to a 1.5-Tesla (1 T = 104 Gauss) homogeneous DC magnetic field, and in LAF-1 mice continuously exposed for 72 h to a sinusoidal 60-Hz, 1.65-mT (rms) homogeneous AC field. Three types of behavioral tests were employed: (1) Memory of an electroshock-motivated passive avoidance task was assessed in animals that had been trained immediately prior to the field exposure. The strength of memory was varied either by altering the strength of the electric footshock during training, or by administering a cerebral protein synthesis inhibitor, anisomycin, at the time of training. (2) General locomotor activity was measured using a quadrant-crossing test immediately after termination of the magnetic field exposure. (3) Sensitivity of the experimental subjects to the seizure-inducing neuro-pharmacological agent, pentylenetetrazole, was assessed immediately after the field exposure on the basis of three criteria: (a) the percentage of subjects exhibiting a generalized seizure, (b) the mean time to seizure, and (c) the mean seizure level. The results of these studies revealed no behavioral alterations in exposed mice relative to controls in any of the experimental tests with the 1.5-T DC field or the 60-Hz, 1.65-mT (rms) AC field.
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  • 52
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    Bioelectromagnetics 5 (1984), S. 113-115 
    ISSN: 0197-8462
    Keywords: Nernst equation ; temperature derivatives ; cell membranes ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A hyperpolarized current is predicted from the Nernst equation for conditions of positive temperature derivatives with respect to time. This ion current, coupled with changes in membrane channel conductivities, is expected to contribute to a transient potential shift across the cell membrane for silent cells and to a change in firing rate for pacemaker cells.
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  • 53
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    Bioelectromagnetics 5 (1984) 
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    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
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  • 54
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    Bioelectromagnetics 5 (1984), S. 165-172 
    ISSN: 0197-8462
    Keywords: acetylcholinesterase ; microwave ; microwave spectrophotometer-fluorometer ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The effect of 2,450-MHz pulsed microwave radiation on the enzyme activity of membranefree acetylcholinesterase was studied while the enzyme was in the microwave field. We found no significant effect of microwave radiation on enzyme activity using a wide variety of power densities, pulse widths, repetition rates, and duty cycles. This suggests that simple, direct modification by microwave energy of acetylcholinesterase structure and enzymic activity is not related to microwave alteration of acetylcholinesterase central nervous system levels.
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  • 55
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    Bioelectromagnetics 5 (1984), S. 213-220 
    ISSN: 0197-8462
    Keywords: microwaves ; ethanol ; hypothermia ; fluid consumption ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Microwave irradiation of rats by circularly polarized, 2,450-MHz, pulsed waves (2-μs pulses; 500 pps) was performed in waveguides to determine effects on ethanol-induced hypothermia and on ethanol consumption. Rats injected intraperitoneally with ethanol (3 g/kg in a 25% v/v water solution) immediately after 45 min of microwave irradiation exhibited attenuation of the initial rate of fall in body temperature, which was elicited by the ethanol, but exhibited no significant difference in maximal hypothermia as compared with that of sham-irradiated rats. Microwave irradiation did not affect the consumption of a 10% sucrose (w/v) solution by water-deprived rats. However, it enhanced the consumption of a solution of 10% sucrose (w/v) + 15% ethanol (v/v) by water-deprived animals. These results were obtained at a specific absorption rate (SAR) of 0.6 W/kg, which rate of energy dosing would require a power density of 3-6 mW/cm2 if exposure of the animals had occurred to a 12-cm plane wave.
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  • 56
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    Bioelectromagnetics 5 (1984), S. 233-246 
    ISSN: 0197-8462
    Keywords: operant behavior ; observing-responses ; radiofrequency radiation ; colonic temperature ; rhesus monkeys ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Five food-deprived rhesus monkeys were exposed to 225-MHz continuous-wave, and 1.3-GHz, and 5.8-GHz pulsed radiation to determine the minimal power densities affecting performance. The monkeys were trained to press a lever (observing-response) thereby producing signals that indicated availability of food. In the presence of the aperiodically appearing food signals, a detection response on a different lever was reinforced by a food pellet. Continuous, stable responding during 60-min sessions developed and was followed by repeated exposures to radiofrequency radiation. The subjects, restrained in a Styrofoam chair, were exposed to free-field radiation while performing the task. Colonic temperature was simultaneously obtained. Observing-response performance was impaired at increasingly higher power densities as frequency increased from the near-resonance 225 MHz to the above-resonance 5.8 GHz. The threshold power density of disrupted response rate at 225 MHz was 8.1 mW/cm2; at 1.3 GHz it was 57 mW/cm2, and at 5.8 GHz it was 140 mW/cm2. These power densities were associated with reliable increases in colonic temperatures above sham-exposure levels. The mean increase was typically in the range of 1°C, and response-rate changes were not observed in the absence of concomitant temperature increases. In these experiments increase of colonic temperature was a much better predictor of behavioral disruption than was either the power density of the incident field or estimates of whole-body-averaged rates of energy absorption.
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    Bioelectromagnetics 5 (1984) 
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    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
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  • 58
    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.
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    Bioelectromagnetics 5 (1984), S. 323-330 
    ISSN: 0197-8462
    Keywords: pulsed microwaves ; rat ; blood-brain barrier ; 86Rb permeability ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Microwaves (pulsed, 2,450 MHz) at an average power density of 3 W/cm2 were applied directly to the head for 5, 10, or 20 min, producing a peak specific absorption rate of 240 W/kg in the brain, which, after a 10-min exposure, resulted in brain temperatures in excess of 43°C. A bolus of 86Rb in isotonic saline was injected intravenously and an arterial sample was collected for 20 s to determine cardiac output. Compared with unexposed controls, uptake of 86Rb increased most in those regions directly in the path of the irradiation, namely, the occipital and parietal cortex, as well as the dorsal hippocampus, midbrain, and basal ganglia. In a separate group of animals, regional brain-vascular spaces were found to increase with brain temperature. These results support previous observations indicating that reliably demonstrable increases of blood-brain barrier permeability are associated with intense, microwave-induced hyperthermia, and that the observed changes are not due to field-specific interaction.
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  • 60
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    Bioelectromagnetics 1 (1980), S. 131-147 
    ISSN: 0197-8462
    Keywords: electric fields ; rat ; sciatic nerve ; vagus nerve ; superior cervical sympathetic ganglion ; chronic exposure ; 60 Hz ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Several reports have suggested that the nervous system can be affected by exposure to electric fields and that these effects may have detrimental health consequences for the exposed organism. The purpose of this study was to investigate the effects of chronic (30-day) exposure of rats to a 60-Hz, 100-kV/m electric field on synaptic transmission and peripheral-nerve function. One hundred forty-four rats, housed in individual polycarbonate cages were exposed to uniform, vertical, 60-Hz electric fields in a system free of corona discharge and ozone formation and in which the animals did not receive spark discharges or other shocks during exposure. Following 30 days of exposure to the electric field, superior cervical sympathetic ganglia, vagus and sciatic nerves were removed from rats anesthetized with urethan, placed in a temperature-controlled chamber, and superfused with a modified mammalian Ringer's solution equilibrated with 95% O2 and 5% CO2. Several measures and tests were used to characterize synaptic transmission and peripheral-nerve function. These included amplitude, area, and configuration of the postsynaptic or whole-nerve compound-action potential; conduction velocity; accommodation; refractory period; strength-duration curves; conditioning-test (C-T) response, frequency response; post-tetanic response; and high-frequency-induced fatigue. The results of a series of neurophysiologic tests and measurements indicate that only synaptic transmission is significantly and consistently affected by chronic (30-day) exposure to a 60-Hz, 100-kV/m electric field. Specifically, an increase in synaptic excitability was detected in replicated measurements of the C-T response ratio. In addition, there are trends in other data that can be interpreted to suggest a generalized increase in neuronal excitability in exposed animals.
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    Bioelectromagnetics 1 (1980), S. 171-181 
    ISSN: 0197-8462
    Keywords: microwaves ; in vivo ; brain ; adenosine triphosphate (ATP) ; creatine phosphate (CP) ; NADH ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Rat brain was exposed to 591-MHz, continuous-wave (CW) microwaves at 13.8 or 5.0 mW/cm2 to determine the effect on nicotinamide adenine dinucleotide, reduced (NADH), adenosine triphosphate (ATP) and creatine phosphate (CP) levels. On initiation of the in vivo microwave exposures, fluorimetrically determined NADH rapidly increased to a maximum of 4.0%-12.5% above pre-exposure control levels at one-half minute, then decreased slowly to 2% above control at three minutes, finally increasing slowly to 5% above control level at five minutes. ATP and CP assays were performed on sham- and microwave-exposed brain at each exposure time. At 13.8 mW/cm2, brain CP level was decreased an average of 39.4%, 41.1%, 18.2%, 13.1%, and 36.4% of control at exposure points one-half, one, two three, and five minutes, respectively, and brain ATP concentration was decreased an average of 25.2%, 15.2%, 17.8%, 7.4%, and 11.2% of control at the corresponding exposure periods. ATP and CP levels of rat brain exposed to 591-MHz cw microwaves at 5 mW/cm2 for one-half and one minute were decreased significantly below control levels at these exposure times, but were not significantly different from the 13.8 mW/cm2 exposures. For all exposures, rectal temperature remained constant. Heat loss through the skull aperture caused brain temperature to decrease during the five-minute exposures. This decrease was the same in magnitude for experimental and control subjects. Changes in NADH, ATP, and CP levels during microwave exposure cannot be attributed to general tissue hyperthermia. The data support the hypothesis that microwave exposure inhibits mitochondrial electron transport chain function, which results in decreased ATP and CP levels in brain.
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    Bioelectromagnetics 1 (1980), S. 253-270 
    ISSN: 0197-8462
    Keywords: thermal model ; heat transfer ; dosimetry, 80 MHz ; 200 MHz ; absorption of electromagnetic energy ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The human body was modeled by numerical procedures to determine the thermal response under varied electromagnetic (EM) exposures. The basic approach taken was to modify the heat transfer equations for man in air to account for thermal loading due to the energy absorbed from the EM field. The human body was represented in an EM model by a large number of small cubical cells of tissue, and the energy density was determined for each cell. This information was then analyzed by a thermal response model consisting of a series of two-dimensional transient conduction equations with internal heat generation due to metabolism, internal convective heat transfer due to blood flow, external interaction by convection and radiation, and cooling of the skin by sweating and evaporation. This model simulated the human body by a series of cylindrical segments. The local temperature at 61 discrete locations as well as the thermoregulatory responses of vasodilatation and sweating were computed for a number of EM field intensities and two frequencies, one near whole-body resonance.
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  • 63
    ISSN: 0197-8462
    Keywords: calcium ions ; brain tissue ; radiofrequency (RF) radiation ; amplitude modulation ; power-density window ; 16-Hz modulation ; 50 MHz ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: In previous experiments changes were found in calcium-ion efflux from chickbrain tissue that had been exposed in vitro to 147-MHz radiation across a specific range of power densities when the field was amplitude modulated at 16 Hz. In the present study, 50-MHz radiation, similarly modulated as a sinusoid, was found to produce changes in calcium-ion efflux from chick brains exposed in vitro in a Crawford cell. Exposure conditions were optimized to broaden any power-density window and to enhance the opportunity to detect changes in the calcium-ion efflux. The results of a power-density series demonstrated two effective ranges: One spanning a range from 1.44 to 1.67 mW/cm2, and the other including 3.64 mW/cm2, which were bracketed by no-effect results at 0.72, 2.17, and 4.32 mW/cm2. Peaks of positive findings are associated with near-identical rates of energy absorption: 1.4 μW/g at 147 MHz, and 1.3 μW/g at 50 MHz, which indicates that the enhanced-efflux phenomenon is more dependent on the intensity of fields in the brain than on the power density of incident radiation. In addition, the phenomenon appears to occur at multiples of some, as yet unknown, rate of radiofrequency (RF) energy absorption. Because of the extremely small increments of temperature associated with positive findings (〈 4 × 10-4°C), and the existence of more than one productive absorption rate, a solely thermal explanation appears extremely unlikely.
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    Bioelectromagnetics 1 (1980), S. 313-323 
    ISSN: 0197-8462
    Keywords: microwave ; blood-brain barrier ; Evans blue ; sodium fluorescein ; brain and body temperatures ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: This investigation was aimed at correlating changes of blood-brain-barrier permeability with the quantity and distribution of absorbed microwave energy inside the brain of adult Wistar rats anesthetized by sodium pentobarbital. Through use of thermographic methods and a direct-contact applicator at the animal's head, the pattern of absorbed microwave energy was determined. Indwelling catheters were placed in the femoral vein and in the left external carotid artery. Evans blue and sodium fluorescein in isotonic saline were used as visual indicators of barrier permeation. Exposure to pulsed 2,450-MHz radiation for 20 min at average power densities of 0.5, 1, 5, 20, 145 or 1,000 mW/cm2, which resulted in average specific absorption rates (SARs) of 0.04, 0.08, 0.4, 1.6, 11.5 or 80.0 mW/g in the brain, did not produce staining, except in the pineal body, the pituitary gland, and the choroid plexus  -  regions that normally are highly permeable. Except for these regions, staining was also absent in the brains of sham-exposed animals. The rectal temperature, as monitored by a copper-constantan thermocouple, showed a maximum increase of less than 0.75°C from a mean pre-exposure temperature of 36.6°C. The highest brain temperature recorded in a similar group of animals using a thickfilm carbon thermistor was less than 41.0°C.
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    Bioelectromagnetics 1 (1980), S. 345-352 
    ISSN: 0197-8462
    Keywords: electromagnetic pulsed (EMP) fields ; pentobarbital-induced sleeping time ; serum chemistry ; serum triglycerides ; creatine phosphokinase (CPK) ; Dutch rabbits ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Dutch rabbits were acutely exposed to electromagnetic pulsed (EMP) fields (pulse duration 0.4μs, field strengths of 1-2 kV/cm and pulse repetition rates in the range of 10 to 38 Hz) for periods of up to two hours. The dependent variables investigated were pentobarbital-induced sleeping time and serum chemistry (including serum triglycerides, creatine phosphokinase (CPK) isoenzymes, and sodium and potassium). Core temperature measured immediately pre-exposure and postexposure revealed no exposure-related alterations. Over the range of field strengths and pulse durations investigated no consistent, statistically significant alterations were found in the end-points investigated.
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    Bioelectromagnetics 1 (1980), S. 379-388 
    ISSN: 0197-8462
    Keywords: near fields ; plane-wave spectrum (PWS) ; energy deposition ; layering resonance ; multilayered slab model ; plane wave ; fast Fourier transform ; 2,450 MHz ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The electromagnetic energy deposited in a semi-infinite slab model consisting of skin, fat, and muscle layers is calculated for both plane-wave and near-field exposures. The plane-wave spectrum (PWS) approach is used to calculate the energy deposited in the model by fields present due to leakage from equipment using electromagnetic energy. This analysis applies to near-field exposures where coupling of the target to the leakage source can be neglected. Calculations were made for 2,450 MHz, at which frequency the layered slab adequately models flat regions of the human body. Resonant absorption due to layering is examined as a function of the skin and fat thicknesses for plane-wave exposure and as a function of the physical extent of the near-field distribution. Calculations show that for fields that are nearly constant over at least a free-space wavelength, the energy deposition (for the skin, fat, and muscle combination that gives resonant absorption) is equal to or less than that resulting from plane-wave exposure, but is appreciably greater than that obtained for a homogeneous muscle slab model.
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    Bioelectromagnetics 1 (1980), S. 429-431 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
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  • 68
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    Bioelectromagnetics 1 (1980), S. 415-428 
    ISSN: 0197-8462
    Keywords: microwave radiation ; pulse-modulated ; operant behavior ; chronic irradiation ; waveguide exposure ; performance ; microwave dosimetry ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A facility for the exposure of small animals to pulse-modulated microwave radiation (PM MWR) concurrent with their performance of operant behavioral tasks is described. The computer-managed facility comprises an array of 32 individual waveguide exposure cells, each enclosing instrumental conditioning apparatus within a plastic subhousing. The distribution of the microwave electric field intensity within the waveguide was measured by a nonperturbing probe and the modifications induced by the behavioral apparatus and animal within the waveguide determined. Input and interior voltage standing wave ratios are presented to characterize the design of the chambers and to demonstrate the suitability of the chambers for whole-body irradiation of rat. The specific absorption rate (SAR) is presented utilizing data derived from incremental thermometric examination of saline loads and of selected sites in rat carcasses. This is compared with the whole-body SAR derived from the input/ output energy balance equation for the waveguide. The results of continuous monitoring of the SAR by the latter method, while unrestrained rats were engaged in operant and exploratory behavior within the waveguide, are utilized to derive a relationship between chamber input power and the dose rate for adult rats behaviorally active within the waveguide. From these data, we conclude that the experimental array provides a practical method for exposing a large number of animals to PM MWR for long periods of time and coincident with the establishment and/or performance of complex operant behavior.
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    Bioelectromagnetics 2 (1981), S. 61-69 
    ISSN: 0197-8462
    Keywords: FM radio broadcast ; VHF-TV broadcast ; UHF-TV broadcast ; electromagnetic field strengths ; personnel hazard ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Radiofrequency electric and magnetic fields have been measured around 11 large broadcast stations and tall FM/TV towers in Sweden. The results show that operating personnel may be exposed to fields exceeding by several times the present standard for occupational exposure to RF radiation. Maintenance personnel are especially vulnerable to exposure when climbing energized towers. The present study indicates that the transmitters should be switched off during the performance of certain tasks on the tower. Safe passage of maintenance personnel near energized antennas of certain types is impossible without a drastic reduction of the transmitted power. In the stations, the RF leakage radiation was generally low, but when work was done with the cabinet doors of the transmitter open, high field strengths were found in the vicinity of the transmitter even though it was switched off. It was found that the transmitter acted as a tuned receiver of energy from the other transmitters.
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    Bioelectromagnetics 2 (1981), S. 51-60 
    ISSN: 0197-8462
    Keywords: 2880-MHz microwaves ; rats ; submaxillary salivary gland ; thermoregulation ; tissue conductivity ; tissue hydration ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Hypersalivation is an important mechanism for heat dissipation by animals without sweat glands. The water content and conductivity (at 20 kHz) in sub-maxillary salivary gland (SSG) and in other tissues were investigated in adult male rats exposed to microwaves (2880 MHz, 1.5 μs pulses at 1000 Hz) or to conventional heat at 40 °C. Eighty rats in one series were exposed, one at a time, for 30 min to microwaves producing a specific absorption rate (SAR) of 4.2,6.3,6.8,8.4,10.8 or 12.6 W/kg. Fifty rats were sham-exposed under similar environmental conditions. In the second series, ten rats were sham-exposed, 33 rats were exposed, one at time, for 15, 30 or 60 min to microwaves at a SAR of 9.5 W/kg, and 32 rats were exposed for similar periods to conventional heat at 40 °C. In rats of the first series colonic temperatures were elevated significantly at a SAR of 4.2 W/kg, while SSG water content and conductivity increased significantly at SAR values of 6.3 W/kg and higher. In the second series of experiments increases in colonic temperature and SSG water content were greater after 15 and 30 min of microwave exposure than after exposure to heat. Also, SSG conductivity was significantly depressed by heat and significantly increased by microwaves after exposure for 15 or 30 min. The results support the hypothesis that water content and conductivity of SSG of rats can be used as a sensitive specific test of a microwave induced thermal response.
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  • 71
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    Keywords: 2450-MHz microwaves ; complement receptors ; diffusion chambers ; soluble factors ; immune system ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: These studies indicate that the increase in the frequency of complement receptor-positive (CR+) spleen cells observed 6 days after a 30-min exposure to 2450-MHz microwaves is not the result of microwave-induced alterations of lymphocyte recirculation patterns, but is mediated by a soluble, humoral factor produced by cells within the spleen.
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    Bioelectromagnetics 2 (1981), S. 105-121 
    ISSN: 0197-8462
    Keywords: 60-Hz electric fields ; ELF radiation ; rat endocrinology ; organ weights ; hormones ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Adult male rats were exposed or sham-exposed to 60-Hz electric fields without spark discharges, ozone, or significant levels of other secondary variables. No effects were observed on body weights or plasma hormone levels after 30 days of exposure at an effective field strength of 68 kV/m. After 120 days of exposure (effective field strength = 64 kV/m), effects were inconsistent, with significant reductions in body weight and plasma levels of follicle-stimulating hormone and corticosterone occurring in one replicate experiment but not in the other. Plasma testosterone levels were significantly reduced after 120 days of exposure in one experiment, with a similar but not statistically significant reduction in a replicate experiment. Weanling rats, exposed or sham-exposed in electric fields with an effective field strength of 80 kV/m from 20 to 56 days of age, exhibited identical or closely similar growth trends in body and organ weights. Hormone levels in exposed and sham-exposed groups were also similar. However, there was an apparent phase shift between the two groups in the cyclic variations of concentrations of hormones at different stages of development, particularly with respect to follicle-stimulating hormone and corticosterone. We concluded that 60-Hz electric fields may bring about subtle changes in the endocrine system of rats, and that these changes may be related to alterations in episodic rhythms.
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    Bioelectromagnetics 2 (1981), S. 161-167 
    ISSN: 0197-8462
    Keywords: microwave effects on CNS ; pulsed microwaves ; brain calcium efflux ; 1 GHz ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: In this study we investigated the prospect of microwave-induced alteration of 45Ca2+ efflux from rat neural tissue at low pulse repetition frequencies and low power densities under in vitro conditions. Rat cerebral tissue, preloaded with 45Ca2+, was exposed to pulsed-microwave radiation (1-GHz carrier frequency) according to one of several PRF-power density exposure schemes: 16 Hz at 0.5, 1.0, 2.0, or 15 mW/cm2, or 32 Hz at 1.0 or 2.0 mW/cm2 average power density. Measurements of radioactivity in the efflux medium and in the tissue sample were used to calculate an efflux value for each sample. The results indicate that the radiation conditions used did not alter calcium efflux in rat brain tissue.
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    Bioelectromagnetics 2 (1981) 
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    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 75
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    Bioelectromagnetics 2 (1981), S. 169-185 
    ISSN: 0197-8462
    Keywords: microwave radiation ; pulse modulation ; waveguide exposure ; chronic exposure ; operant behavior ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Two measures of performance were used to study the effects of pulse-modulated microwave radiation (PM MWR) on schedule-controlled operant behavior of rats: 1) cued (SD), fixed-ratio (FR) bar pressing for food reinforcement; and 2) noncued (Sd) bar pressing in the absence of food reinforcement. The animals were irradiated and the behavioral data were obtained concurrently, during daily three-hour sessions, five days per week for six to nine weeks. Each experiment began with a two to three-week baseline interval of sham irradiation; a two to three-week interval of sham irradiation followed the irradiation phase. The irradiated animals were exposed to 1.3-Ghz PM MWR (pulse width of 1 microsecond at 600 pulses per second) at whole-body, average specific absorbed-dose rates of from 1.5-6.7 mW/g. Control and irradiated animals were tested in identical, cylindrical waveguide exposure/behavioral assemblies; different groups of irradiated and sham-irradiated animals were used for each dose rate. At 1.5 mW/g, the levels of SD operant responding by control and irradiated animals were comparable, and showed similar progressive diminutions over the course of each daily session. Sd operant responding was more variable, but again comparable, with both groups showing similar, progressive declines in rate of responding during each session. At 3.6 mW/g, no specific effects on SD operant response rates were observed. However, there was an initial and transient increase in the rate of extinction of Sd responding. At 6.7 mW/g, SD response rates were slightly reduced, whereas there was a major reduction in noncued (Sd) operant responding followed by a sharp rebound during the first post-MWR week. This marked reduction in Sd operant responding at MWR onset was in contrast to the relative stability and persistence of FR responding for food reinforcement.
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  • 76
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    Bioelectromagnetics 2 (1981), S. 217-225 
    ISSN: 0197-8462
    Keywords: lipid vesicles ; Na+ leakage ; 2450 MHz ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Sonicated egg phosphatidylcholine vesicles loaded with 24Na+ were exposed at 20mW to a frequency-modulated (3 Hz) microwave field in the range of 2350 to 2550 MHz, or at 80 mW to a 2450-MHz CW (continuous wave) field, in a waveguide. The vesicle suspension absorbed microwaves at about 1 mW/ml and 25 mW/ml (CW experiment). The average temperature change of the irradiated suspension was 〈 0.1 °C from ambient. Leakage of 24Na+ from the vesicles for up to 19 hours was measured. No difference was noted in the movement of 24Na+ from the vesicles in the irradiated and control dispersions.
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  • 77
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    Bioelectromagnetics 1 (1980), S. 183-198 
    ISSN: 0197-8462
    Keywords: operant behavior ; observing-responses ; microwaves ; vigilance ; dosimetry ; rats ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The effects of microwave irradiation at two different frequencies (1.28 and 5.62 GHz) on observing-behavior of rodents were investigated. During daily irradiation, eight male hooded rats performed on a two-lever task; depression of one lever produced one of two different tones and the other lever produced food when depressed in the presence of the appropriate tone. At 5.62 GHz, the observing-response rate was not consistently affected until the power density approximated 26 mW/cm2 at 1.28 GHz, the observing-response rate of all rats was consistently affected at a power density of 15 mW/cm2. The respective whole-body specific absorption rates (SARs) were 4.94 and 3.75 W/Kg. Measurements of localized SAR in a rat-shaped model of simulated muscle tissue revealed marked differences in the absorption pattern between the two frequencies. The localized SAR in the model's head at 1.28 GHz was higher on the side distal to the source of radiation. At 5.62 GHz the localized SAR in the head was higher on the proximal side. It is concluded that the rat's observing behavior is disrupted at a lower power density at 1.28 than at 5.62 GHz because of deeper penetration of energy at the lower frequency, and because of frequency-dependent differences in anatomic distribution of the absorbed microwave energy.
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  • 78
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    Bioelectromagnetics 1 (1980) 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
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  • 79
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    Bioelectromagnetics 1 (1980), S. 299-312 
    ISSN: 0197-8462
    Keywords: ELF electric field ; 60-Hz ; avoidance behavior ; activity ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: In repeated short-term tests (four sessions, each of 45-minute duration), and one longer test (a 23.5-hour session), behavior of rats was evaluated in a long, narrow shuttlebox. One side of the box was exposed to an electric field at various strengths, while a visually identical opposite side was shielded from exposure. In the short-term tests, rats generally remained shielded from electric fields of 90 kV/m and greater during the first session, and maintained this response in subsequent sessions. In the longer test, this same preference response was demonstrated at field strengths of 75 kV/m and greater; however, at 25 and 50 kV/m, rats exhibited a statistically significant preference for the exposed region of the shuttlebox, but only during the light portion of a 12-hour light: 12-hour dark cycle. Exposed animals made more traverses than sham-exposed controls between the two ends of the shuttlebox during the first hour of the test. The experimental data support the hypothesis that the observed behavioral effects are the result of direct interaction of the electric field with the animal, and not the result of secondary factors such as electric shock, corona discharge, audible noise, ozone, or vibration of the experimental apparatus.
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  • 80
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    Bioelectromagnetics 1 (1980), S. 1-20 
    ISSN: 0197-8462
    Keywords: 2,450 MHz CW microwaves ; behavioral thermoregulation ; body temperature ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Squirrel monkeys (Saimiri sciureus) trained to regulate environmental temperature (Ta) behaviorally were exposed in the far field of a horn antenna to ten-minute periods of 2,450 MHz CW microwaves. Incident power density ranged from 1 to 22 mW/cm2. The corresponding specific absorption rate (SAR), derived from temperature increments in saline-filled styrofoam models, ranged from 0.15 to 3.25 W/kg. Controls included exposure to infrared radiation of equivalent incident energy and no radiation exposure. Normal thermoregulatory behavior produces tight control over environmental and body temperatures; most monkeys select a Ta of 34-36°C. Ten-minute exposures to 2,450 MHz CW microwaves at an incident power density of 6-8 mW/cm2 stimulated all animals to select a lower Ta. This threshold energy represents a whole-body SAR of 1.1 W/kg, about 20% of the resting metabolic rate of the monkey. Thermoregulatory behavior was highly efficient, and skin and rectal temperatures remained stable, even at 22 mW/cm2 where the preferred Ta was lowered by as much as 4°C. No comparable reduction in selected Ta below control levels occurred during exposure to infrared radiation of equal incident power density.
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  • 81
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    Bioelectromagnetics 1 (1980), S. 389-396 
    ISSN: 0197-8462
    Keywords: microwaves ; nonionizing radiation ; embryogenesis ; enzymes ; cardiac muscle ; 2.45 GHz ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Although exposure to nonionizing electromagnetic radiation has been reported to cause a variety of systemic alterations during embryonic development, there are few reports of the induction of specific physiologic or morphologic changes in the myocardium. This study was designed to examine the effects of microwave radiation on cardiogenesis in Japanese quail embryos exposed during the first eight days of development to 2.45-GHz continuous-wave microwaves at power densities of 5 or 20 mW/cm2. The specific absorption rates were 4.0 and 16.2 mW/g, respectively. The ambient temperature for each exposure was set to maintain the embryonated eggs at 37.5 °C. This did not preclude thermal gradients in the irradiated embryos since microwaves may not be uniformly absorbed. The test exposure levels did not induce changes in either the morphology of the embryonic heart or the ultrastructure of the myocardial cells. Analysis of the enzymatic activities of lactate dehydrogenase, glutamic oxaloacetic transaminase, and creatine phosphokinase failed to reveal any statistically significant differences between the nonexposed controls and those groups exposed to either 5 or 20 mW/cm2. The data indicate that 2.45-GHz microwave radiation at 5 or 20 mW/cm2 has no effect on the measured variables of the Japanese quail myocardium exposed during the first eight days of development.
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  • 82
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    Keywords: 2450-MHz radiation ; complement receptors ; endotoxin ; T cells ; genetic control ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: In attempting to evaluate the mechanisms responsible for susceptibility to the inductive increase in splenic complement receptor-positive (CR+) cells following exposure to 2450-MHz microwaves, it was found that sensitivity to microwave-induced CR+cell increases was under genetic control. In particular, evidence was accumulated suggesting that regulation was under the control of a gene or genes closely associated with but outside of the mouse major histocompatibility complex (H-2). All responsive strains of mice tested were of the H-2k haplotype, while mice of the H-2a, H-2b, H-2d and H-2i5 haplotypes were refractory to the microwave-induced increases in CR+ cells. By utilizing certain H-2k strains of mice that were genetically unable to respond to endotoxin, we were able to show that these strains of mice responded to microwaves, but not to endotoxin, by increasing CR+ cells. Microwave-induced increases in CR+cells were not mimicked by the intraperitoneal injection of hydrocortisone. Athymic mice responded to microwave exposure, indicating that this event was not regulated by the T-cell population. Mice less than eight weeks old were found not to be susceptible to exposure to 2450-MHz microwaves. These studies indicate that microwaves do induce changes in the population of cells with specific cell-surface receptors, that susceptibility to these changes is under genetic control, and that it is unlikely that endotoxin, corticosteroids, or regulatory T cells play a significant role in the mechanisms regulating these increases.
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  • 83
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    Bioelectromagnetics 2 (1981), S. 1-11 
    ISSN: 0197-8462
    Keywords: electric fields ; 60-Hz ; biological effects ; dosimetry ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: An analysis is given of the interaction between extremely low-frequency (ELF) electric fields and animals of arbitrary body shape. This analysis is based on three approximations which are valid in the ELF range: In living tissues, capacitive (displacement) currents are negligible compared to conduction currents; effects resulting from the finite velocity of propagation of electromagnetic fields are negligible; skin effect in living tissues is negligible. Major conclusions of the analysis are: (a) The electric field outside the body, the induced charge on the surface of the body, and the total current crossing any section through the body (eg, through the neck or limbs) are completely determined by the characteristics of the applied ELF electric field, the shape of the body, its location relative to ground and other conductors, and any conduction currents from the body to ground or other conductors. (b) All of the quantities in (a) can be measured using conducting animal models. (c) The magnitudes of the electric field outside the body and the induced charge density on the surface of the body are independent of frequency, in the ELF range, when the body is either insulated from or shorted to ground (and any other conductors in the system). (d) The only quantities affected by the electrical properties of the tissues comprising the body are the current density and electric field inside the body. (e) The electric field outside and inside a body will be unchanged by a scaled change in its size.
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  • 84
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    Bioelectromagnetics 2 (1981), S. 33-50 
    ISSN: 0197-8462
    Keywords: electric fields ; 60-Hz ; dosimetry ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The level of exposure of laboratory animals to 60-Hz electric fields is commonly specified in terms of the unperturbed field strength present before the introduction of experimental subjects and their cages. In the research reported in this paper, rats were housed in two parallel rows of 12.4 cm × 25.1 cm × 10.2 cm high plastic cages resting on the lower electrode of a parallel-plate exposure system, and the actual perturbed electric fields experienced by an experimental animal were investigated. The most important results are: 1) Reducing the spacing between the exposure electrodes from 8.7 to 1.7 times the height of a singly exposed rat model, while maintaining a constant unperturbed field strength, resulted in a 15% increase in the electric field at the highest point on the surface of the body and a 10% increase in the short-circuit current of the model. 2) For multiple animal exposures, increases of 10% in both the field at the highest point of the body and the short-circuit current were observed when the electrode spacing was reduced from 8.7 to 2.6 times the height of a rat. 3) Plastic cages caused 1 - 6% reductions in the electric field at the surface of the body, except very near the cage walls, where enhancements of more than 20% were observed. 4) When 16 rats were simultaneously exposed, the short-circuit current, Is, of an individual subject of weight W (in g), that was surrounded on all sides by other rats of weight W, was reduced from the short-circuit current, Iu, measured with the same subject individually exposed as follows: during a 12 h light (sleeping) cycle, Is/Iu = 1.00 - 0.0173W1/2; during a 12 h night (awake) cycle, Is/Iu = 1.00 - 0.0136W1/2.
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    Bioelectromagnetics 2 (1981), S. 77-80 
    ISSN: 0197-8462
    Keywords: microwaves ; L1210 leukemia ; central nervous system ; methotrexate ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: One-GHz microwave (MW) irradiation at a power density of 5 mW/cm2 was combined with methotrexate (MTX) in an attempt to treat more effectively central nervous system (CNS) L1210 leukemia in DBA/2J mice. When mice with CNS leukemia were treated with the combination of MW and MTX, there was no improvement in survival compared with a group of animals treated with MTX alone; however, the group that received MTX before the MW exposure had a significantly reduced survival time compared with the group treated with MTX alone or with the group to which MTX was administered after MW.
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  • 86
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    Bioelectromagnetics 2 (1981), S. 89-92 
    ISSN: 0197-8462
    Keywords: microwave pulse ; motor activity ; brain acetylcholine ; 2,450 MHz ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Mice were exposed to a single 15-ms or 25-ms pulse of 2,450-MHz microwaves which increased brain temperature by 2 °C or 4 °C, respectively. Immediately after exposure, the mice became hypokinetic but began recovering within 5 minutes. The 25-ms pulse (18.7 j deposited in the brain) caused a significant decrease in acetylcholine content of the whole brain, probably owing to increased permeability of the membrane.
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  • 87
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    Bioelectromagnetics 1 (1980), S. 397-404 
    ISSN: 0197-8462
    Keywords: antibody response ; microwaves ; immunology ; 9-GHz pulsed radiation ; infectivity ; mouse ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A significant increase was observed in the circulating antibody titers of mice exposed to 9-GHz pulsed microwaves at an average power density of 10 mW/ cm2, two hours per day for five days compared with sham-irradiated animals. The mice were previously immunized with type III pneumococcal polysaccharide. Following irradiation, a portion of the immunized animals were challenged with virulent Streptococcus pneumoniae, type III. Ten days after challenge, mortality was essentially the same in the two groups, but during the ten day period, there was a noticeable increase in the survival time of the irradiated animals compared with the sham-irradiated animals, suggesting that the increased circulating antibody response afforded some degree of temporary protection to the animals.
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  • 88
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    Bioelectromagnetics 2 (1981), S. 203-215 
    ISSN: 0197-8462
    Keywords: 2,450-MHz microwaves ; neutrophil ; colony-forming cells ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Human marrow cells were irradiated with 2450-MHz CW microwaves in a fluid-filled waveguide irradiation system. Cell exposure was conducted by placing a marrow cell suspension in 20-μl glass microcapillary tubes that were positioned in the exposure chamber, and irradiated at power densities from 31 to 1,000 mW/cm2 (with corresponding specific absorption rates of 62 to 2,000 mW/g) for 15 minutes. The temperature of the sample was maintained at a fixed point. Sham-irradiated (SI) and microwave-irradiated (MWI) cells were cultured in a methylcellulose culture system for neutrophil colony proliferation. There was no reduction in neutrophil colony number on days 6-7 or 12-14 in cells exposed at 31 or 62 mW/cm2, but as the power density was increased to 1,000 mW/cm2, there was a reduction in colony number of MWI cells compared with SI cells. The microwave interaction with the human neutrophil colony-forming cells was apparently not related to temperature rise, or to the state of cell cycle, and was irreversible.
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  • 89
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    Bioelectromagnetics 2 (1981), S. 241-246 
    ISSN: 0197-8462
    Keywords: monkey cerebellum ; Purkinje cells ; nonionizing radiation ; microwaves ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Pregnant squirrel monkeys were exposed to 2450-MHz (CW) microwaves at an equivalent power density of 10 mW/cm2 (SAR 3.4 mW/g) for three hours daily in a cavity-cage module. The exposure began when pregnancy was determined by a hormonal method, and continued through the offspring's first 9.5 months. After irradiation, the brains of the offspring were fixed with formaldehyde, and the inferior vermis of each cerebella was removed and processed for histologic observations. Purkinje cell density in the uvula was determined in sagittal serial sections. There was no significant difference between control and experimental animals in the number of Purkinje cells per mm of Purkinje cell line (linear density), as well as in the density of Purkinje cells in the Purkinje cell layer.
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  • 90
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    Bioelectromagnetics 2 (1981), S. 279-284 
    ISSN: 0197-8462
    Keywords: 970 MHz ; rats ; long-term exposure ; serum chemistry ; hematology ; lymphocytes ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Rats (N = 16) exposed individually in circularly polarized waveguides to 970-MHz electromagnetic radiation (SAR=2.5 mW/g, 22 h daily for 70 consecutive days) had significantly higher serum levels of triglycerides, albumin, and total protein compared with sham-irradiated controls. No difference was observed in the weights, hematologic profile, or in vitro lymphocyte responses to mitogens between these two groups. The higher serum levels of triglycerides in radiofrequency-radiation-exposed rats suggest a non-specific stress reaction.
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  • 91
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    Bioelectromagnetics 2 (1981), S. 285-289 
    ISSN: 0197-8462
    Keywords: growth inhibition ; magnetic fields ; ELF ; Escherichia coli ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Cultures of Escherichia coli kept at 0 °C in a phosphate buffer solution were exposed to a sinusoidal weak 60- or 600-Hz magnetic field of strength 2 × 10-3 Tesla. A decrease of more than 40% in bacterial count was observed after a 60-h exposure to the magnetic field. Electron micrographs of exposed bacteria show ruptured cell walls, possibly due to the breaking away of flagella under the influence of the sinusoidally varying electromotive force.
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  • 92
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    Bioelectromagnetics 2 (1981), S. 315-328 
    ISSN: 0197-8462
    Keywords: electric fields ; 60 Hz ; honeybees ; transmission lines ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Honeybee colonies exposed under a 765-kV, 60-Hz transmission line at 7 kV/m show the following sequence of effects: 1) increased motor activity with transient increase in hive temperature; 2) abnormal propolization; 3) impaired hive weight gain; 4) queen loss and abnormal production of queen cells; 5) decreased sealed brood; and 6) poor winter survival. When colonies were exposed at 5 different E fields (7, 5.5, 4.1, 1.8, and 0.65-0.85 kV/m) at incremental distances from the line, different thresholds for biologic effects were obtained. Hive net weights showed significant dose-related lags at the following exposures: 7 kV/m, one week; 5.5 kV/m, 2 weeks; and 4.1 kV/m, 11 weeks. The two lowest exposure groups had normal weight after 25 weeks. Abnormal propolization of hive entrances did not occur below 4.1 kV/m. Queen loss occurred in 6 of 7 colonies at 7 kV/m and 1 of 7 at 5.5 kV/m, but not below. Foraging rates were significantly lower only at 7 and 5.5 kV/m. Hive weight impairment and abnormal propolization occur at lower E-field intensity than other effects and limit the “biological effects corridor” of the transmission line to approximately 23 m beyond a ground line projection of each outer phase wire. Intrahive E fields of 15-100 kV/m were measured with a displacement current sensor. Step-potential-induced currents up to 0.5 μA were measured in an electrically equivalent bee model placed on the honeycomb in a hive exposed at 7 kV/m. At 1.8 kV/m body currents were a few nanoamperes, or two orders of magnitude lower, and these colonies showed no effects. E-field versus electric shock mechanisms are discussed.
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  • 93
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    Bioelectromagnetics 2 (1981), S. 357-370 
    ISSN: 0197-8462
    Keywords: rat ; electrocardiogram ; stationary magnetic fields ; T-wave augmentation ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A field strength dependent increase in the amplitude of the T-wave signal in the rat electrocardiogram (ECG) was observed during exposure to homogeneous, stationary magnetic fields. For 24 adult Sprague-Dawley and Buffalo rats of both sexes, the T-wave amplitude was found to increase by an average of 408% in a 2.0 Tesla (1 Tesla = 104 Gauss) field. No significant magnetically induced changes were observed in other components of the ECG record, including the P wave and the QRS complex. The minimum field level at which augmentation of the T wave could be detected was 0.3 Tesla. The magnetically induced increase in T-wave amplitude occurred instantaneously, and was immediately reversible after exposure to fields as high as 2.0 Tesla. No abnormalities in any component of the ECG record, including the T wave, were noted during a period of 3 weeks following cessation of a continuous 5-h exposure of rats to a 1.5-Tesla field. The heart rate and breathing rate of adult rats were not altered during, or subsequent to, application of fields up to 2.0 Tesla. The effect of animal orientation within the field was tested using juvenile rats 3-14 days old. The maximum increase in T-wave amplitude was observed when subjects were placed with the long axis of the body perpendicular to the lines of magnetic induction. These experimental observations, as well as theoretical considerations, suggest that augmentation of the signal amplitude in the T-wave segment of the ECG may result from a superimposed electrical potential generated by aortic blood flow in the presence of a stationary magnetic field.
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    Bioelectromagnetics 2 (1981), S. 371-380 
    ISSN: 0197-8462
    Keywords: electric fields ; 60 Hz ; pineal gland ; circadian rhythm ; melatonin ; 5 methoxytryptophol ; acetyl transferase ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: As a component of studies to search for effects of 60-Hz electric field exposure on mammalian endocrine function, concentrations of melatonin, 5-methoxytryptophol, and serotonin-Nacetyl transferase activity were measured in the pineal glands of rats exposed or sham-exposed at 65 kV/m for 30 days. In two replicate experiments there were statistically significant differences between exposed and control rats in that the normal nocturnal increase in pineal melatonin content was depressed in the exposed animals. Concentrations of 5-methoxytryptophol were increased in the pineal glands of the exposed groups when compared to shamexposed controls. An alteration was also observed in serotonin-N-acetyl transferase activity, with lower levels measured in pineal glands from exposed animals.
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  • 95
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    Bioelectromagnetics 2 (1981), S. 403-406 
    ISSN: 0197-8462
    Keywords: electric fields ; power-frequency ; 60 Hz ; dosimetry ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Calculated electric-field strengths averaged over the body surfaces of grounded humans, swine, rats, horses, and cattle exposed to vertical, uniform, power-frequency electric fields are presented. To produce the same average fields over the body surfaces of grounded animals, as that experienced by a grounded man exposed to an unperturbed vertical field of 10 kV/m, the following unperturbed fields are required: swine, 19 kV/m; rat, 37 kV/m; horse, 18 kV/m; cow, 18 kV/m.
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    Bioelectromagnetics 2 (1981), S. 227-239 
    ISSN: 0197-8462
    Keywords: 60-Hz electric fields ; rats ; soleus muscle ; plantaris muscle ; neuromuscular function ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Neuromuscular function in adult male rats was studied following 30 days of exposure to a 60-Hz electric field at 100 kV/m (unperturbed field strength). Isometric force transducers were attached to the tendons of the plantaris (predominantly fast twitch), and soleus (predominantly slow twitch) muscles in the urethan-anesthetized rat. Square-wave stimuli were delivered to the distal stump of the transected sciatic nerve. Several measurements were used to characterize neuromuscular function, including twitch characteristics, chronaxie, tetanic and posttetanic potentiation, and fatigue and recovery. The results from three independent series of experiments are reported. Only recovery from fatigue in slow-twitch muscles was consistently and significantly affected (enhanced) by electrifield exposure. This effect does not appear to be mediated by field-induced changes in either neuromuscular transmission, or in the contractile mechanism itself. It is suggested that the effect may be mediated secondary to an effect on mechanisms regulating muscle blood flow or metabolism.
    Additional Material: 6 Ill.
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  • 97
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 3 (1982), S. 25-28 
    ISSN: 0197-8462
    Keywords: dielectric dispersion ; alamethicin ; dipole moment ; molecular shape ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Dielectric constant and loss of alamethicin in solvents of various degrees of lipophilicity (namely mixtures of n-octanol and dioxane) have been measured at frequencies from 5 kHz to 50 MHz. By means of a conventional Cole-Cole approach, dielectric properties were evaluated to obtain information about the structural and dipolar properties of the peptide in view of its function as a voltage-dependent pore former in membranes. The results for a pure octanol solvent (together with an apparent molecular weight determined by ultracentrifugation) indicate the existence of primarily monomeric particles of quite elongated shape and of comparatively high dipole moment. Adding dioxane was found to yield considerable aggregation and a decrease of polarity.
    Additional Material: 1 Tab.
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  • 98
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 4 (1983), S. 167-180 
    ISSN: 0197-8462
    Keywords: air ions ; corona discharge inhalation system ; DC electric fields ; small animal exposure system ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Many previous problems in establishing the nature of biological and behavioral effects of small air ions have been due to poor control over the ion-inhalation microclimate, resulting in nonuniform electrical fields and highly uneven concentrations of small air ions. We have developed a corona discharge air ion-inhalation system for use with animals that incorporates rigorous control over the microclimate and produces highly uniform concentrations of small air ions throughout the exposure area.
    Additional Material: 8 Ill.
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  • 99
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 4 (1983), S. 181-191 
    ISSN: 0197-8462
    Keywords: 60-Hz electric fields ; arousal response ; electric field strength ; mice ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: White-footed mice, Peromyscus leucopus, were exposed to 60-Hz electric fields to study the relationship between field strength and three measures of the transient arousal response previously reported to occur with exposures at 100 kV/m. Five groups of 12 mice each were given a series of four 1-h exposures, separated by an hour, with each group exposed at one of the following field strengths: 75, 50, 35, 25, and 10 kV/m; 8 additional mice were sham-exposed with no voltage applied to the field generator. All mice were experimentally naive before the start of the experiment, and all exposures occurred during the inactive (lights-on) phase of the circadian cycle. The first exposure produced immediate increases in arousal measures, but subsequent exposures had no significant effect on any measure. These arousal responses were defined by significant increases of gross motor activity, carbon dioxide production, and oxygen consumption, and were frequently recorded with field strengths of 50 kV/m or higher. Significant arousal responses rarely occurred with exposures at lower field strengths. Responses of mice exposed at 75 and 50 kV/m were similar to previously described transient arousal responses in mice exposed to 100-kV/m electric fields. Less than half of the mice in each of the field strength groups below 50 kV/m showed arousal responses based on Z (standard) scores, but the arousals of the mice that did respond were similar to those of mice exposed at higher field strengths. Polynomial regression was used to calculate the field strength producing the greatest increases for each of the arousal measures. The results show that the amplitude of the transient arousal response is related to the strength of the electric field, but different measures of arousal may have different relationships to field strength.
    Additional Material: 2 Ill.
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  • 100
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 4 (1983), S. 249-255 
    ISSN: 0197-8462
    Keywords: radiofrequency radiation ; 27.12 MHz ; hyperthermia ; teratology ; rat ; embryo ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Five groups of pregnant Sprague-Dawley rats were either sham exposed or were irradiated in a 27.12-MHz radiofrequency (RF) field at 55 A/m and 300 V/m on gestation day 9. The absorbed power (approximately 11 W/kg) caused a relatively rapid increase in the rat's colonic temperature. Rats in group I were sham irradiated for 2.5 h at 0 A/m, 0 V/m. In group II RF irradiation was terminated after the rat's colonic temperature reached 41.0 °C. In group III the 41.0- °C temperature was maintained an additional 15 min by varying the field strength. At both temperatures the teratogenic and embryotoxic effects of the RF-induced hyperthermia increased as the exposure duration increased, but the increase was especially noticeable at 42.0 °C. The results indicate that the teratogenic and embryotoxic effects of RF-induced hyperthermia are related to both the temperature of the dam during exposure and the length of time the dam's temperature remains elevated.
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