Unknown authors
The wave impedance dropped to less than half the far-field value of 377 ohms at distances under 150 m. Body current was measured by placing a person on a ground plane 15 cm above earth and detecting voltage across a known resistor. Measured body currents showed excellent agreement with theoretical values from a prolate spheroidal model of a human on a conductive ground plane.
Unknown authors
Liquid bolus made from saline and ethanol and gel-like bolus made from saline, polyethylene, and TX150 were developed for clinical microwave hyperthermia. Electrical properties of these materials were measured at frequencies from 1 to 10 GHz and temperatures from 25 to 45°C using short-circuited waveguides and a short monopole impedance sensor. The measurement system was validated against published data with better than 4% agreement.
Unknown authors
Forty dams were exposed to 2450 MHz microwaves at 31 mW/g or 17 mW/g for 20 minutes on gestational days 8, 10, 12, or 14, while eight received sham exposures and eight served as cage controls. In the 31 mW/g group, 30% of implantations were resorbed and 17% of fetuses had abnormalities, compared to lower rates in other groups. Fetal body mass decreased at 31 mW/g, and fetal brain mass was affected by treatment condition and gestational day.
Unknown authors
Handling alone lowered pregnancy rate from 86 percent to 72 percent during days 1-6, with further drops to 65 percent at 21 mW/cm2 and 50 percent at 30 mW/cm2, while heated controls showed no extra decrease. Congenital malformations increased significantly only at 30 mW/cm2 during days 6-15, rising from 1.7 percent to 3.1 percent, with two-thirds being cleft palate.
Unknown authors
Researchers irradiated freshly prepared rat liver mitochondria at 8.58 mm (35 GHz) and at 40 discrete wavelengths between 5.00 and 6.00 mm (60 to 50 GHz) to evaluate effects on oxidative phosphorylation. The study found no significant effect of millimeter wave irradiation on oxidative phosphorylation.
Unknown authors
Adult male squirrel monkeys were restrained in an anechoic chamber and trained to select between 15°C and 55°C air temperatures, then exposed to 2450 MHz CW microwaves at incident power densities from 1 to 22 mW/cm². At 6-8 mW/cm² the monkeys significantly reduced their selected air temperature, a threshold corresponding to a whole-body SAR of 1.1 W/kg. Infrared radiation of equal incident energy did not produce a comparable reduction, suggesting microwaves stimulate internal thermoreceptors while infrared stimulates skin receptors. At 22 mW/cm² the preferred air temperature was lowered by up to 4°C while skin and rectal temperatures remained stable.
Unknown authors
Unknown authors
Fifty-eight male Long-Evans rats were exposed to 2.45 GHz continuous-wave microwaves for four hours at power densities of 0, 0.1, 1, 10, 25, and 40 mW/cm². Rats exposed to 0.1 and 1 mW/cm² had significantly lower serum corticosterone than sham-exposed rats, while rats exposed to 40 mW/cm² had significantly higher levels, and no changes occurred at 10 and 25 mW/cm². Colonic temperature increased significantly at 10, 25, and 40 mW/cm² but not at lower intensities.
Unknown authors
Researchers conducted preliminary testing of magnetic field mutagenicity using bacterial systems with field strengths ranging from 0.1 to 1.1 Tesla. Salmonella strain TA98, which mutates by frameshift, did not show an increase in mutation frequency. Initial tests with E. coli, B. subtilis, and Photobacterium fisheri also produced suggestive data of increased mutation frequencies.
Unknown authors
H. Lai, A. Horita, A.W. Guy
Researchers exposed rats to continuous-wave or pulsed 2450-MHz microwaves at 0.6 W/kg for 45 minutes in waveguides or anechoic chambers. Frontal cortical choline uptake decreased under all irradiation conditions. Hippocampal choline uptake decreased in animals exposed to pulsed microwaves. Striatal choline uptake decreased after exposure in the miniature anechoic chamber. Hypothalamic choline uptake was not significantly affected.
Glenn S. Smith
The paper discusses problems in measuring local electric fields in media with spatially inhomogeneous electrical properties like biological tissue. Simple theoretical analyses describe the operation of electrically short hare and insulated electric field probes in a dissipative medium.
K. I. Kuz'mina, N.P. Irodova, L. Yu. Rabichev
Kuz'mina and Irodova reported effects of currents on the CNS during EA and developed a "Mix" procedure with three currents of different frequencies and shapes. They reportedly obtained superior results compared to conventional EA procedures using pulse current plus bias or interference current.
William T. Ham, Jr., A. M. Clarke
Y. Kinouchi, Y. Kubo, T. Ushita, T.S. Tenforde
The model solved simultaneous equations for blood flow velocity distribution and induced electric fields. With a 1 Tesla field and peak aortic flow of 60 cm/s, the induced potential on the thoracic surface near the breasts was about 1 mV, large enough to appear on an electrocardiogram. Induced current densities were about 0.05 A/m² on the vascular wall and 0.02 A/m² 1 cm from the aorta, far below the 1.7 A/m² ventricular fibrillation threshold.
Phillips, Richard D., Hunt, Evans L., King, Nancy W.
R. JOLY, B. SERVANTIE
Leo P. Inglis
Richard G. Olsen, Wayne C. Hammer
The study examined microwave-induced mechanical stress waves in a simulated muscle tissue model. Microwave absorption was mostly confined to within 2 cm of the irradiated surface with an average localized SAR of about 100 W/kg. A distinct stress wave propagated at 1600 m/s with peak pressures of about 300 Pa and remained detectable after traveling 0.61 m with two reflections.
Unknown authors
The study investigated Raman spectroscopy to distinguish tumor cells from normal cells but encountered fluorescence, Rayleigh scattering, and cell settling in liquid media. They identified phosphate buffered saline (PBS) as a nonfluorescent medium suitable for Raman spectroscopy. Suspending cells in agarose immobilized them, eliminated intensity fluctuations, and produced consistent spectra. Preliminary spectra of BHK cells in agarose showed possible Raman lines below 200 cm⁻¹.
Michael H. Repacholi
Q. Balzano, O. Garay, K. Siwiak
Researchers measured energy densities near helical and whip resonant antennas used in portable communication products. They found that in the near field the squared electric field strength reflects stored reactive energy, not radiated power flow. For the 750 MHz resonant dipole the radial field component was dominant out to about 6 cm. At 1 cm distance Helix 1 (Q=25) had a peak E-field energy value about 14 times that of a resonant dipole and Helix 2 (Q=65) about 40 times. At 2 cm distance Helix 1 violated the proposed ANSI guide with 4 mW radiated power and Helix 2 with slightly over 1 mW.
P. E. Братковский
Unknown authors
G. F. Plakhanov, V. V. Vedyushkina
Seven healthy volunteers aged 20-23 years underwent more than 100 plethysmographic tests while exposed to a high frequency field from a DTP diathermy apparatus. The stimulus manipulations did not change the apparatus sound, and calculated temperature rises and induced currents from field changes were far below biological and ambient levels, leading the authors to conclude the field intensity change was the conditioned stimulus.
