Browse 6,486 peer-reviewed studies on electromagnetic field health effects from 4 research libraries.
Showing 2,816 studies in Whole Body / General
T. C. Rozzell, C. C. Johnson, O. P. Gandhi
The temperature probe achieves a precision of +0.1°C when operated in voltage read-out mode. The power probe's voltage rate of change is proportional to microwave power level during the first 5 to 10 seconds of exposure.
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Researchers developed a new radio frequency device that allows uniform heating to any depth without surface injury. In 52 human tumors evaluated, temperatures above 42°C occurred in 81%, above 45°C in 44%, and above 50°C in 37%, while surface and adjacent normal tissues remained at physiologic temperatures. Previous methods caused surface burns in humans with thick subcutaneous tissue despite surface cooling.
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Researchers conducted eight experiments exposing juvenile and young adult rats and young adult mice to 60-Hz electric fields at 100 kV/m for 30 or 120 days. They measured body and organ weights, food and water consumption, metabolic rates, hormone levels, liver composition, bone growth, and blood chemistry. No reproducible significant differences were found in rats, and mice showed essentially the same parameters between exposed and sham-exposed groups.
Unknown authors
Researchers exposed rats to 1.3 GHz pulse-modulated microwave radiation for 3 hours daily over 2-3 weeks at SARs ranging from 0 to 2.6 mW/g. After exposure, they measured the time to loss of righting reflex following barbital injection and found no significant differences between exposed and control rats at SARs of 0.42, 0.96, and 2.6 mW/g. In a separate experiment, rats exposed at 2.6 mW/g for two weeks were injected with dopamine and tested on an open field; although defecation was more frequent in exposed rats, no significant differences in motor activity were observed.
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The probe uses a gallium arsenide sensor that absorbs near-infrared light at 907 nm, with absorption changing as temperature varies. The probe consists of 0.085-mm glass fibers for light transmission and reception, with a tip diameter smaller than a 25-gauge needle for tissue implantation. The system operates from 15°C to 55°C with a resolution of 0.01°C and absolute accuracy better than 0.1°C. An 8085 microprocessor controls up to six probes simultaneously, handling linearization, display, and calibration via a built-in calibrator or an external reference.
Unknown authors
The extended-boundary-condition method (EBCM) has been used with prolate spheroid models of man and animals to generate much of the theoretical data used in the current dosimetry handbook. When large a/b ratios (typical of man) or large magnitude permittivities are used with the EBCM, the matrix becomes ill-conditioned, thus disallowing calculations above a certain maximum frequency. Researchers followed the algorithm of Golub and Reinsch to develop a FORTRAN program for inversion of ill-conditioned complex matrices, which appeared significantly more stable than standard matrix inversion procedures.
Unknown authors
Researchers compared threshold values for magnetophosphenes and electrophosphenes in ten visually normal volunteers using magnetic flux densities up to 40 mT and electric currents up to 0.3 mA at frequencies from 10 to 50 Hz. Thresholds were measured at a retinal luminance of 3 cd/m2 under both broad-spectrum and 572 nm background illumination. The threshold curves were nearly identical up to about 20 Hz but diverged at higher frequencies. Magnetophosphene thresholds showed a local sensitivity minimum at 30-35 Hz that was not present in electrophosphene thresholds at any of three electrode sites.
Unknown authors
Evans blue dye was injected either intracarotidally or intravenously to detect barrier opening. Microwave exposure produced no Evans blue staining in the brain except in the pineal body, pituitary gland, and choroid plexus, which lack a barrier. One brain exposed to 5 mW/cm2 and another brain exposed to 40 mW/cm2 showed unilateral hemispherical staining in several brain regions after intracarotid dye injection.
Unknown authors
Male Long-Evans rats were exposed to 1.29 GHz pulsed microwave radiation at 15 mW/cm² for 90 minutes in an anechoic chamber. The authors concluded that adrenocortical function is stimulated at a lower power density at 1.29 GHz than previously observed at 2.45 GHz.
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The paper presents the design of a broadband microwave applicator covering 150 MHz to 1100 MHz for hyperthermia. Filling the horn with circulating formamide scaled the frequency band down to 150 MHz–1.1 GHz and provided surface cooling.
Unknown authors
Researchers investigated electromagnetic emissions from the human body across the frequency region 10^3 Hz - 2-10^9 Hz using tunable radiometers. They found that the body acts as a purely thermal radiator down to about 10^4 Hz, with radiation temperature equal to body temperature at all tested positions above that frequency. Below 10^4 Hz, emissions exceeded thermal levels and varied with electrode type, location, and muscle state, peaking with coaxial needle electrodes in contracted muscle.
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Researchers studied microwave-induced pressure waves in a simulated muscle tissue phantom using a radar transmitter at 5.62 GHz. The pressure waves propagated at approximately 1460 m/s in the phantom, slower than in saline, and a single pulse remained detectable after traveling more than 45 cm with reflection. Attenuation was higher and pressure levels appeared lower in the phantom compared to saline, and the authors suggested that focusing and resonance could occur under certain conditions.
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Researchers investigated the accuracy of microwave methods for detecting early interstitial edema using isolated dog lungs to eliminate interference from chest wall and other extrapulmonary structures. Results showed an immediate and direct change in the phase of the microwave-transmitted signal as the isolated lung weight changed, strongly indicating accuracy for early pulmonary edema detection.
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Researchers created intrabony defects in rabbit mandibles and applied three levels of direct current for 14 days. Control mandibles showed minimal bone growth while all current-treated animals demonstrated bone growth. Cathodal stimulation was most effective for bone mass, whereas anodal stimulation showed some bone growth but also bone destruction away from defects. Tetracycline labeling confirmed active mineralization in new bone, and histology showed the electrically stimulated bone had a normal appearance. All three current levels were effective for stimulating mandibular alveolar bone.