Unknown authors
Researchers evaluated three BRH applicators and four microwave hyperthermia applicators by thermographically analyzing them using planar phantoms, measuring leakage radiation, net power required to deliver 235 W/kg SAR, and heating patterns. The BRH 2450 MHz applicator had less than 5 mW/cm² leakage for both direct contact and 1 cm spacing, while the 915 MHz applicators exceeded that level when spaced 1 cm from the phantom. The depth of penetration into muscle tissue was nearly identical for both frequencies, at about 2 cm beneath the fat-muscle interface.
Unknown authors
Researchers measured local cerebral blood flow in multiple brain regions of conscious rats using a radioactive iodoantipyrine technique. Rats were exposed for 30 minutes to pulsed microwaves at 1 mW/cm² or 15 mW/cm² average power density, or sham exposure. Both exposure levels increased blood flow by 10 to 144 percent in 16 of 20 regions, with the largest significant increases in the pineal, hypothalamus, and temporal cortex at 1 mW/cm² and in the pineal, temporal cortex, inferior colliculus, and medial geniculate at 15 mW/cm².
Unknown authors
Unknown authors
Unknown authors
Researchers developed a computational scheme that combines an iteration process with the tensor integral equation method to quantify induced electric fields in electrically large bodies. In a test on a muscle layer irradiated by a 1 GHz plane wave, the 8-cell model with iteration produced results comparable to a 64-cell model at a lower computation cost.
Unknown authors
Unknown authors
The liposomes undergo thermally induced phase transitions between 30 °C and 40 °C. Samples were exposed to continuous-wave 2.4 GHz microwave radiation at power levels up to 25 mW/cm² while held at 36 °C. An increase in bilayer fluidity appeared above a threshold of 10–15 mW/cm², and at ~20 mW/cm² the fluidity change matched a ~3 °C temperature shift while bulk temperature rose only ~1 °C. The authors concluded a steady-state temperature difference exists between the bilayer interior and the surrounding aqueous medium under these exposure conditions.
Unknown authors
Unknown authors
The paper reviews research on the ability of humans to perceive the natural electromagnetic fields of the earth and includes new data from interviews with sensitive persons. The review also references studies showing that animals and plants can orient to the earth's electromagnetic field. Sun Bear, an American Indian medicine man, reports seeing earth energy fields, and Dr. Valerie Hunt's studies indicate some people may see invisible fields as accurately as instrumentation. Dr. William Tiller proposes a model where the human nervous system acts as an antenna to detect exterior field changes.
Unknown authors
Animals were irradiated at 30 to 40 mW/g until rectal temperature reached 42.5 to 43.0 °C, then temperatures were recorded for over three hours. At baseline, cortical and hypothalamic temperatures were significantly lower than rectal temperatures in all three species. After heating, cortical temperature fleetingly exceeded rectal temperature in all species, while hypothalamic temperature exceeded rectal temperature only in rabbits. Brain temperatures fell rapidly in the first minute after exposure while rectal temperature declined much more slowly.
Unknown authors
Unknown authors
Unknown authors
Researchers exposed paired frog sciatic nerves treated with ouabain to microwaves at a specific absorption rate of 10 W/kg while stimulating at 50 pulse pairs per second. At 50 ppps, ouabain reduced the half-decay time from about two hours to under 30 minutes, and microwave exposure caused no significant further shortening. At a lower stimulation rate of 5 ppps, half-decay times returned to near two hours and again showed no significant difference between exposed and unexposed nerves. The authors suggested that microwave effects on nerve vitality are associated with decay of ionic gradients normally maintained by active transport.
Unknown authors
Unknown authors
Unknown authors
Bureau of Radiological Health, Food and Drug Administration
Microwaves and RF fields are almost totally reflected from metals, transmitted through plastics, ceramics, paper, or glass, and absorbed by most biological materials, particularly those with high water content. The document explains near-field and far-field regions, noting that the near field dominates when the distance is much smaller than the wavelength and that the far field begins where the ratio of electric to magnetic field approaches 377 ohms. It specifies measurement techniques for frequencies from 1 MHz to 100 GHz and distinguishes emission standards from exposure standards.
D.M. Witters, S.M. Hinkley, A.R. Lapp
Researchers measured electrical output signals of several commercially available TENS devices using a digital waveform signal recorder across the ANSI/AAMI standard loading circuit. Most devices generated asymmetrical biphasic waves, while some produced monophasic or polyphasic pulses. Some devices, such as the Maxima, showed fairly accurate pulse rate control settings with nearly linear actual pulse rate across the control range. The study concluded a wide variety of designs and performance exists, and further research is needed to correlate parameters with safety and effectiveness.
Unknown authors
The optic chiasm was removed from two groups of 14-day-old Sprague-Dawley rats, one exposed to a 60 Hz 20 kV/m electric field from birth and the other sham-exposed under field-free conditions. The chiasms were sectioned, stained with hematoxylin and eosin, and coded for blind analysis. Myelin sheath area was measured using a light microscope and a Zeiss MOP-2 Digitizer, and group means were compared with a two-tailed t-test.
Wieslaw Wiktor-Jedrzejczak et al.
W.D. Travers, R.J. Vetter
Researchers randomly assigned pregnant rats to six groups and exposed them daily for 15 days to 0, 5, or 25 mW/cm² of 2450 MHz microwave radiation for 10 or 20 minutes. Blood samples were taken before exposure on day 5 and on days 10, 15, and 20 of pregnancy to measure serum iron, unsaturated iron binding capacity, and total iron binding capacity. Total iron binding capacity increased with higher power densities, and significant differences were found between power densities, sampling days, and exposure durations. Rats exposed to 25 mW/cm² for 20 minutes showed a statistically significant increase in total iron binding capacity, while control and low-exposure groups initially dropped.
Unknown authors
Bryan Parker, Seymour Furman, Doris J. W. Escher
N. N. Goncharova, V. B. Karamyshev, N. V. Maksimenko
The paper examines occupational hygiene and effects of ultrashort wave electromagnetic fields on TV and radio station employees. Physiological investigations at workplaces found that operators servicing ultrashort wave transmitters exhibit functional changes in cardiovascular and central nervous systems during the day. The high-frequency electromagnetic field of considerable intensity was identified as an especially unfavorable factor. Protective and prophylactic measures are needed to improve work conditions.
Donald R. King, John W. Hathaways, Donald C. Reynolds
