Chimpanzee problem comprehension: insufficient evidence (original) (raw)
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ANALYSIS OF HEATING CHARACTISTICS OF ANIMALS EXPOSED TO MICROWAVES
The whole body for differing animals like rat, dog, Rabbit were exposed at different microwave field intensities. At increasing body temperatures in these animals, cooling reaches a maximum limit, and beyond this undergoes a failure presumably primarily due to a central failure of the respiratory mechanism. Also metabolism is increased under these conditions, partly because of specific temperature dependence, and partly because of an increased respiratory effort. The data presented in tables at the lower rates the three animal species were roughly the same. At higher temperatures, a change is observed with a few of rats and rabbits whereas with the dogs actually retained to the abscissa where body temperature was maintained at the elevated level above the metabolism.
A microwave exposure system for primates
Radio Science, 1977
Development of a system for exposing nonhuman primates of sizes to and including stumptail macaques (Macact arctoides) at 2.45 GHz for long periods without constraining the animals (except for cage confinement) is described. The exposure chamber is a multimode mode-stirred cubical microwave cavity of edge length about 90 cm internally; within the cavity is a dielectric cage sufficiently large to house a 15-kg primate. The cavity is excited by a Type 2M53 magnetton. Radiopaque windows are provided for viewing and ventilation. Forward and reflected powers are measured with calibrated diode detectors in a bidirectional coupler between the magnetton and the cavity. Power values are set by phase-angle selection and are held constant by detector-output feedback to a thyristor control circuit. Containers of saline were used as phantoms, i.e., as first approximations to the RF loads presented by monkeys. Calorimetric measurements were made to determine energy absorption values for various quantities and spatial distributions of saline. The results indicate that the dose rate at any given input power is insensitive to phantom location (indicative of isotropy) and is inversely related to the mass of saline within. After the development of the prototype, 12 units were constructed for concurrent chronic irradiation of two squirrel monkeys in each module. A summary is presented of calorimetric measurements on saline-containing dolls serving as phantoms; these measurements were performed to determine net values of RF input power into a cavity unit that are thermally equivalent to specified power-density values of plane-wave irradiation for the same duration of exposure. 1.
Bioelectromagnetics, 1987
Anatomic variability in the deposition of radiofrequency electromagnetic energy in mammals has been well documented. A recent study [D'Andrea et al., 19851 reported specific absorption rate (SAR) hotspots in the brain, rectum and tail of rat carcasses exposed to 360-and to 2,450-MHz microwave radiation. Regions of intense energy absorption are generally thought to be of little consequence when predicting thermal effects of microwave irradiation because it is presumed that heat transfer via the circulatory system promptly redistributes localized heat to equilibrate tissue temperature within the body. Experiments on anesthetized, male Long-Evans rats (200-260 g) irradiated for 10 or 16 min with 2,450, 700, or 360 MHz radiation at SARs of 2 Wlkg, 6 Wlkg, or 10 Wl kg indicated that postirradiation localized temperatures in regions previously shown to exhibit high SARs were appreciably above temperatures at body sites with lower SARs. The postirradiation temperatures in the rectum and tail were significantly higher in rats irradiated at 360 MHz and higher in the tail at 2,450 MHz than temperatures resulting from exposure to 700 MHz. This effect was found for whole-body-averaged SARs as low as 6 Wlkg at 360 MHz and 10 W/kg at 2,450 MHz. In contrast, brain temperatures in the anesthetized rats were not different from those measured in the rest of the body following microwave exposure.
Thermoregulatory adjustments in squirrel monkeys exposed to microwaves at high power densities
Bioelectromagnetics, 1985
The present study was undertaken to investigate the thermal adjustments of squirrel monkeys exposed in a cold environment to relatively high energy levels of microwave fields. The animals (Suirniri sciureus) were equilibrated for 90 min to a cool environment (T, = 20 "C) to elevate metabolic heat production (M). They were then exposed for brief (10-min) or long (30-min) periods to 2,450-MHz continuous-wave microwaves. Power densities (MPD) were 10, 14, 19, and 25 mW/cmZ during brief exposures and 30, 35, 40, and 45 mW/cm2 during long exposures (rate of energy absorption: SAR = 0.15 [W/kg]/ [mW/cm*]). Individual exposures were separated by enough time to allow physiological variables to return to baseline levels. The results confirm that each microwave exposure induced a rapid decrease in M. In a 20 "C environment, the power density of a 10-min exposure required to lower M to approximate the resting level was 35 mW/cm2 (SAR = 5.3 Wlkg). During the long exposures, 20 min was needed to decrease M to its lowest level. Cessation of irradiation was associated with persistence of low levels of M for periods that depended on the power density of the preceding microwave exposure. Vasodilation, as indexed by changes in local skin temperature, occurred at a high rate of energy absorption (SAR = 4.5 Wlkg) and was sufficient to prevent a dramatic increase in storage of thermal energy by the body; vasoconstriction was reinstated after termination of irradiation. Patterns of thermophysiological responses confirm the influence both of peripheral and of internal inputs to thermoregulation in squirrel monkeys exposed to microwaves in a cool environment.
Physical aspects of microwaves in relation to man and experimental animals. General discussion
Bulletin of the New York Academy of Medicine, 1979
School of Medicine): A number of questions concern us as physicians who have an obligation to advise patients as well as, of course, to the more important problem of public health. We know how to measure ionizing radiation and have come here to learn how to measure nonionizing radiation. We understand the complexities of this. Yet we find that comments were made about the role of flat reflectors and we wonder how that affects the dose exposure to the housewife in microwave ovens. We wonder how broad that beam is from the antennae of TV and from radar, which are supposed to miss the earth and go over it and thus not expose the people at the beaches. We hear that one gets measurable amounts of microwave radiation. We are not sure how
This study was designed to identify and measure changes in thermoregulatory responses, both behavioral and physiological, that may occur when squirrel monkeys are exposed to 2450-MHz continuous wave microwaves 40 hrlweek for 15 weeks. Power densities of 1 or 5 mW/cm2 (specific absorption rate = 0.16 Wikg per mW/cm*) were presented at controlled environmental temperatures of 25, 30, or 35 "C. Standardized tests, conducted periodically, before, during, and after treatment, assessed changes in thermoregulatory responses. Dependent variables that were measured included body mass, certain blood properties, metabolic heat production, sweating, skin temperatures, deep body temperature, and behavioral responses by which the monkeys selected a preferred environmental temperature. Results showed no reliable alteration of metabolic rate, internal body temperature, blood indices, or thermoregulatory behavior by microwave exposure, although the ambient temperature prevailing during chronic exposure could exert an effect. An increase in sweating rate occurred in the 35 "C environment, but sweating was not reliably enhanced by microwave exposure. Skin temperature, reflecting vasomotor state, was reliably influenced by both ambient temperature and microwaves. The most robust consequence of microwave exposure was a reduction in body mass, which appeared to be a function of microwave power density.
Thermoregulatory consequences of long-term microwave exposure at controlled ambient temperatures
Bioelectromagnetics, 1985
This study was designed to identify and measure changes in thermoregulatory responses, both behavioral and physiological, that may occur when squirrel monkeys are exposed to 2450-MHz continuous wave microwaves 40 hrlweek for 15 weeks. Power densities of 1 or 5 mW/cm2 (specific absorption rate = 0.16 Wikg per mW/cm*) were presented at controlled environmental temperatures of 25, 30, or 35 "C. Standardized tests, conducted periodically, before, during, and after treatment, assessed changes in thermoregulatory responses. Dependent variables that were measured included body mass, certain blood properties, metabolic heat production, sweating, skin temperatures, deep body temperature, and behavioral responses by which the monkeys selected a preferred environmental temperature. Results showed no reliable alteration of metabolic rate, internal body temperature, blood indices, or thermoregulatory behavior by microwave exposure, although the ambient temperature prevailing during chronic exposure could exert an effect. An increase in sweating rate occurred in the 35 "C environment, but sweating was not reliably enhanced by microwave exposure. Skin temperature, reflecting vasomotor state, was reliably influenced by both ambient temperature and microwaves. The most robust consequence of microwave exposure was a reduction in body mass, which appeared to be a function of microwave power density.
Radio Science, 1977
In order for meaningful comparisons to be made between experiments from different laboratories, reliable dosimetry is needed for biological systems exposed to microwave radiation. We present an improved analytical method for determining energy absorption which uses heating and cooling curves. The method is demonstrated for in vitro samples that were exposed to microwave radiation in two different exposure systems. Advantages and disadvantages of the method, as well as practical considerations, are discussed. 1.
Radio Science, 1977
In order for meaningful comparisons to be made between experiments from different laboratories, reliable dosimetry is needed for biological systems exposed to microwave radiation. We present an improved analytical method for determining energy absorption which uses heating and cooling curves. The method is demonstrated for in vitro samples that were exposed to microwave radiation in two different exposure systems. Advantages and disadvantages of the method, as well as practical considerations, are discussed. 1.
Radio frequency heating at 9.4T (400.2 MHz): In vivo thermoregulatory temperature response in swine
Magnetic Resonance in Medicine, 2009
In vivo thermoregulatory temperature response to RF heating at 9.4 T was studied by measuring temperatures in nine anesthetized swine. Temperatures were measured in the scalp, brain, and rectum. The RF energy was deposited using a four loop head coil tuned to 400.2 MHz. Sham RF was delivered to three swine to understand thermal effects of anesthesia (animal weight = 54.16 kg, SD = 3.08 kg). Continuous wave RF energy was delivered to the other six animals for 2.5-3.4 hours (animal weight = 74.01 ± 26.0 kg, heating duration = 3.05 ± 0.29 hours). The whole head specific absorption rate (SAR) varied between 2.71 W/kg and 3.20 W/kg (SAR = 2.93 ± 0.18 W/ kg). Anesthesia caused the brain and rectal temperatures to drop linearly. Altered thermoregulatory response was detected by comparing the difference in the temperature slopes before and after the RF delivery from zero. RF heating statistically significantly altered the rate of cooling down of the animal. The temperature slope changes correlated well with the RF energy per unit head weight and heating duration, and the maximum rectal temperature change during heating in heated animals. The temperature slope changes did not correlate well to the whole head average SARs.