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Seattle, Washington, USA Introduction There is a general concern on the possible hazardous health effects of exposure to radiofrequency electromagnetic radiation RFR emitted from wireless communication devices.
The following is a brief summary of scientific research on the effects of RFR exposure on the nervous system. For readers who are not familiar with the jargon of biological experiments, I have underlined the main conclusions of the research described.
Unlike the conditions in most previous research on the biological effects of RFR in which whole body exposure was studied, the effects of cellular telephone-related exposure involve repeated exposure with variable durations of a relatively constant amount of body tissue i.
In considering the biological effects of RFR, the intensity and frequency of the radiation and exposure duration are important determinants of the responses. For repeated exposure, as in the case of the use of cellular telephones, homeostatic compensatory response can occur.
On the other hand, since a relatively constant amount of body tissue is exposed, cumulative effect could occur and lead to an eventual breakdown of homeostasis and adverse health consequences.
Data from some of the experiments described below do suggest that RFR effects are cumulative over time. Most of the energy from a cellular telephone antenna is deposited in the skin and the outer portion of the brain cerebral cortex.
From theoretical calculations e. A logical concern is whether the deposited energy could locally affect the blood-brain-barrier. A transient change in blood-brain-barrier permeability could have important health consequences. In addition, possible morphological, metabolic, physiological, and genetic changes in neural tissues should also be considered.
These effects could lead to temporary or permanent functional changes in the nervous system. Blood-Brain-Barrier The blood-brain-barrier is a biological barrier surrounding the brain.
It blocks the entry of certain, and possibly harmful, molecules in the general blood circulation from entering the central nervous system. Local SARs at the surface of the brain, where the blood-brain-barrier is located, were usually not known. This limits the extrapolation of data in the existing literature to cellular telephone exposure.
With regard to the intensity of exposure, the conclusion from most of the studies is that a high intensity of RFR is required to alter the permeability of the blood-brain-barrier.
Significant changes in brain or body temperature seem to be a necessary condition for the effect to occur. For example, Chang et al. In another study, Goldman et al.
Brain temperature of the animals was increased to 43 oC by the radiation. Increases in 86Rb uptake in various regions in the left hemisphere of the brain were observed. Ethanol reduced RFR-induced increase in brain temperature.
Sutton and Carroll  reported an increase in permeability of horseradish peroxidase into the brain of the rat, when the brain temperature was raised to oC by focal heating of the head with continuous-wave MHz RFR. In addition, cooling the body of the animals before exposure could counteract this effect of RFR.
The conclusion that RFR-induced hyperthermia is a cause of the change in blood-brain-barrier permeability was further substantiated by a study by Moriyama et al. When low-intensity RFR was studied, generally, no significant effect on the blood-brain-barrier was observed. For example, Gruenau et al.
They also reported no significant increase in penetration of both compounds into the brain due to RFR exposure; but they reported an increase in 14C-sucrose entry into the hypothalamus when the ambient temperature of exposure was at 40 oC. This increase in permeability was suggested to be due to the hyperthermia induced in the animals exposed in high ambient temperature.
They reported no significant change in permeability into the brain of 3H-inulin and 14C-sucrose after the exposure.
They concluded that RFR did not significantly affect the penetration of the tracers into the brain. Even though most studies indicate that changes in brain-brain-barrier occurs only after exposure to RFR of high intensities with significant increase in tissue temperature, several studies have reported increases in permeability after exposure to RFR of relatively low intensities.
Interestingly, a more pronounced effect was observed when the animals were exposed to pulsed MHz RFR at a lower average power density of 0.Integrative Management of Invasive Insect Pests: Quiz 1 of a pesticide to bees.
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It is possible to get an artificial radiation of the millimeter range (wavelength mm), called Electromagnetic Radiation and Life: Bioelementological Point of View. NEUROLOGICAL EFFECTS OF RADIOFREQUENCY ELECTROMAGNETIC RADIATION. In order to understand the possible health effects of exposure to RFR from mobile telephones, one needs first to understand the effects of these different parameters and how they interact with each other.
Electromagnetic radiation, the larger family of wave-like phenomena to which visible light belongs (also known as radiant energy), is the primary vehicle transporting energy through the vast reaches of the universe. Electromagnetic radiation, the larger family of wave-like phenomena to which visible light belongs (also known as radiant energy), is the .