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Evaluation of Specific Absorption Rate as a Dosimetric Quantity for Electromagnetic Fields Bioeffects

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Abstract

To evaluate SAR as a dosimetric quantity for EMF bioeffects, and identify ways for increasing the precision in EMF dosimetry and bioactivity assessment. We discuss the interaction of man-made electromagnetic waves with biological matter and calculate the energy transferred to a single free ion within a cell. We analyze the physics and biology of SAR and evaluate the methods of its estimation. We discuss the experimentally observed non-linearity between electromagnetic exposure and biological effect. WE FIND THAT: a) The energy absorbed by living matter during exposure to environmentally accounted EMFs is normally well below the thermal level. b) All existing methods for SAR estimation, especially those based upon tissue conductivity and internal electric field, have serious deficiencies. c) The only method to estimate SAR without large error is by measuring temperature increases within biological tissue, which normally are negligible for environmental EMF intensities, and thus cannot be measured. SAR actually refers to thermal effects, while the vast majority of the recorded biological effects from man-made non-ionizing environmental radiation are non-thermal. Even if SAR could be accurately estimated for a whole tissue, organ, or body, the biological/health effect is determined by tiny amounts of energy/power absorbed by specific biomolecules, which cannot be calculated. Moreover, it depends upon field parameters not taken into account in SAR calculation. Thus, SAR should not be used as the primary dosimetric quantity, but used only as a complementary measure, always reporting the estimating method and the corresponding error. Radiation/field intensity along with additional physical parameters (such as frequency, modulation etc) which can be directly and in any case more accurately measured on the surface of biological tissues, should constitute the primary measure for EMF exposures, in spite of similar uncertainty to predict the biological effect due to non-linearity.
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... The maximum of this additional velocity is independent of the frequency of the field (ω), and is much smaller for usual field intensities than the ion velocity through an open channel (u o = 0.25 m/s), which in turn is more than 10 3 times smaller than its corresponding average thermal velocity u kT (168). Thus, the described ion forced-oscillation does not add to tissue temperature and this mechanism is 'non-thermal', in contrast to the known heating ability of the high intensity microwaves (128). ...
... The information is always contained in the ELF signals that modulate the RF (4). Significant experimental evidence shows that the bioactive parameters in a complex signal are its ELF components, and that non-modulated and non-pulsed RF signals alone do not usually induce biological effects (4,44,45,(151)(152)(153)(154)(155)(156)(157)(158)(159), apart from heating when they possess high enough frequency and intensity (128,(168)(169)(170). Therefore, the present study suggests that the vast majority of non-thermal effects attributed till now to various types of RF EMF-exposure, are actually due to their ELF/ULF components. ...
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Exposure of animals/biological samples to human‑made electromagnetic fields (EMFs), especially in the extremely low frequency (ELF) band, and the microwave/radio frequency (RF) band which is always combined with ELF, may lead to DNA damage. DNA damage is connected with cell death, infertility and other pathologies, including cancer. ELF exposure from high‑voltage power lines and complex RF exposure from wireless communication antennas/devices are linked to increased cancer risk. Almost all human‑made RF EMFs include ELF components in the form of modulation, pulsing and random variability. Thus, in addition to polarization and coherence, the existence of ELFs is a common feature of almost all human‑made EMFs. The present study reviews the DNA damage and related effects induced by human‑made EMFs. The ion forced‑oscillation mechanism for irregular gating of voltage‑gated ion channels on cell membranes by polarized/coherent EMFs is extensively described. Dysfunction of ion channels disrupts intracellular ionic concentrations, which determine the cell's electrochemical balance and homeostasis. The present study shows how this can result in DNA damage through reactive oxygen species/free radical overproduction. Thus, a complete picture is provided of how human‑made EMF exposure may indeed lead to DNA damage and related pathologies, including cancer. Moreover, it is suggested that the non‑thermal biological effects attributed to RF EMFs are actually due to their ELF components.
... The total energy absorption of RF-EMR by the tissue is affected by various factors, such as biological complexity (species, strain, age, and sex) and engineering complexity (RF dosimetry, modulation, exposure parameters, and time-intensity factor) (Chou et al., 1996;Panagopoulos et al., 2013). The intensity of the RF field and exposure duration are crucial parameters that can cause a biological effect (36). ...
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Exposure to radiofrequency electromagnetic radiation (RF-EMR) from various wireless devices has increased dramatically with the advancement of technology. One of the most vulnerable organs to the RF-EMR is the testes. This is due to the fact that testicular tissues are more susceptible to oxidative stress due to a high rate of cell division and mitochondrial oxygen consumption. As a result of extensive cell proliferation, replication errors occur, resulting in DNA fragmentation in the sperm. While high oxygen consumption increases the level of oxidative phosphorylation by-products (free radicals) in the mitochondria. Furthermore, due to its inability to effectively dissipate excess heat, testes are also susceptible to thermal effects from RF-EMR exposure. As a result, people are concerned about its impact on male reproductive function. The aim of this article was to conduct a review of literature on the effects of RF-EMR emitted by wireless devices on male reproductive hormones in experimental animals and humans. According to the findings of the studies, RF-EMR emitted by mobile phones and Wi-Fi devices can cause testosterone reduction. However, the effect on gonadotrophic hormones (follicle-stimulating hormone and luteinizing hormone) is inconclusive. These findings were influenced by several factors, which can influence energy absorption and the biological effect of RF-EMR. The effect of RF-EMR in the majority of animal and human studies appeared to be related to the duration of mobile phone use. Thus, limiting the use of wireless devices is recommended.
... [2][3][4] This means that the oscillation induced as a result of a transfer of energy from a polarized electromagnetic oscillation to molecules in ground state with cell suspensions will be most pronounced for small molecules, such as electrically charged ions and polar water molecules. 48 Larger, bound molecules, such as those of the lipid bilayer, will also absorb some of the electromagnetic radiation, yet the magnitude of oscillations induced by such a transfer of energy may be signicantly smaller and difficult to quantify. The EMF-induced oscillations, i.e., vibrations, of water molecules have the potential to induce bilayer permeability of liposomes without affecting their integrity, as demonstrated in this experiment. ...
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Membrane model systems capable of mimicking live cell membranes were used for the first time in studying the effects arising from electromagnetic fields (EMFs) of 18 GHz where membrane permeability was observed following exposure. A present lack of understanding of the mechanisms that drive such a rapid change in membrane permeabilization as well as any structural or dynamic changes imparted on biomolecules affected by high-frequency electromagnetic irradiation limits the use of 18 GHz EMFs in biomedical applications. A phospholipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) labelled with a fluorescent marker 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(lissamine rhodamine B sulfonyl) (rhodamine-DOPE) was used in constructing the giant unilamellar vesicles (GUVs). After three cycles of exposure, enhanced membrane permeability was observed by the internalisation of hydrophilic silica nanospheres of 23.5 nm and their clusters. All-atom molecular dynamics simulations of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membranes exposed to high frequency electric fields of different field strengths showed that within the simulation timeframe only extremely high strength fields were able to cause an increase in the interfacial water dynamics characterized by water dipole realignments. However, a lower strength, high frequency EMF induced changes of the water hydrogen bond network, which may contribute to the mechanisms that facilitate membrane permeabilization in a longer timeframe.
... The formula below was used to calculate the result. The value of SAR was calculated from the electric field and tissue density [20]. The electric fields of 900, 1800, and 2100 MHz are 15.613, 18.192, and 17.660 V/m, respectively. ...
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The study aimed to discover a link between the liver and brain's functional status due to frequency dependent-radiofrequency electromagnetic radiation (RF-EMR). 40 Wistar rats were randomly classified as control (sham-exposed) and EMR exposed groups. Animals were exposed to 900, 1800, and 2100 MHz with thespecific absorption rate (SAR) 0.434 (W/Kg), 0.433 (W/Kg), and 0.453 (W/Kg) respectively. Animal exposure was limited at 1 hour/day, 5 days/week for 1 month with a restricted power density (900 MHz- 11.638µW/m², 1800- 11.438 µW/m² and 2100 MHz frequency- 8.237 µW/m²). Exposure at various frequencies showed a frequency-dependent change in the body weight and hematologic parameters (RBCs, WBCs, platelets, hemoglobin, and hematocrit) as compared with the control group (P ≤ 0.01)(P ≤ 0.001). A significant elevation in serum transaminases and bilirubin, urea, uric acid, and creatinine was noted, whereas albumin significantly decreased after EMR exposure (P ≤ 0.01)(P ≤ 0.001). The blood glucose, lipid peroxidation, triglycerides, and cholesterol were elevated while adenosine triphosphatases, acetylcholinesterase, and tissue antioxidants such as glutathione, superoxide dismutase, catalase, glutathione reductase, glutathione Peroxidase, glutathione-S-transferase, and glucose-6-phosphate dehydrogenases were decreased significantly (P ≤ 0.001). Histopathological observations of the liver showed centrilobular mononuclear cell infiltration and swelling in sinusoidal spaces, while in the brain degenerated pyramidal and Purkinje neurons were seen. Furthermore, Substantial evidence was found that the brain is more susceptible to oxidative mutilation compare to the liver of exposed animals. In conclusion, RF-EMR exposure showed oxidative damage to the liver, increasing the incidence of brain damage in a frequency-dependent manner. • Highlights • EMR exposure showed frequency-dependent toxicity. • Alterations in blood profile and modifications in the serological markers. • Increasing lipid peroxidation indicating membrane damage. • Inhibition of acetylcholinesterase activity affecting cholinergic neurotransmission. • EMR exposure resulted in the loss of cellular energy and production of excess amounts of ROS thereby altering several antioxidant enzymes. • Histopathological evidence of severe degenerative changes in the liver and brain.
... The second quadrant B (upper left) contains the voxels where SAR values overcome the safety limit (SAR 'hot spots'), but, because of the effects of blood perfusion and diffusion parameters, the temperature rise remains below the threshold. It is known that high SAR values do not necessarily imply a high biological effect; moreover, low SAR values may have larger biological effects than higher ones in certain cases [67]. Consequently, quadrant B may also contain voxels of tissues bearing a low hazard potential despite their high SAR values. ...
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... Conversely, the natural electromagnetic radiation such as infrared, visible, ultraviolet, x-rays, and c which are produced by atomic events are not polarized. When the polarized non-ionizing electromagnetic wave passes through a biological tissue composed of free ions, polar and charged molecules, it induces a forced oscillation on each of these particles [36]. The oscillating ions may cause a new signal via opening of the voltage and/or mechanically gated channels. ...
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... Technical difficulties (effects of the human body, field strength, and polarization rapidly varied over time-fading, calibrating equipment, etc.), methodological problems (measuring protocol) and data analysis-type drawbacks (non-detects, using means, medians, etc.) [14,68,69] must be taken into account to prevent conditioning results for the research [13,15,43,[70][71][72][73], as mentioned in the next section. The exposimeter was configured to measure every 10 s for 25 h, among which only 24 h were considered; half an hour before and after the measurement process was discarded to avoid potential errors. ...
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Numerous studies have shown that radiofrequency electromagnetic radiation (RF‐EMR) may negatively affect human health. We detected the effect of 3500 MHz RF‐EMR on anxiety‐like behavior and the auditory cortex (ACx) in guinea pigs. Forty male guinea pigs were randomly divided into four groups and exposed to a continuous wave of 3500 MHz RF‐EMF at an average specific absorption rate (SAR) of 0, 2, 4, or 10 W/kg for 72 h. After exposure, malondialdehyde (MDA) levels, antioxidant enzyme activity, anxiety‐like behavior, hearing thresholds, cell ultrastructure, and apoptosis were detected. Our results revealed that hearing thresholds and basic indexes of animal behavior did not change significantly after exposure (P > 0.05). However, the MDA levels of ACx were increased (P < 0.05), and catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH‐px) activities were decreased (P < 0.05) in the exposure groups compared to the sham group. Ultrastructural changes of ACx, including swollen mitochondria and layered myelin sheaths, were observed. Cytochrome‐c relocalization, caspase‐9, and cleaved caspase‐3 activation were detected in the exposure groups. In conclusion, these results suggest that oxidative stress is an important mechanism underlying the biological effects of RF‐EMR, which can induce ultrastructural damage to the ACx and cell apoptosis through a mitochondria‐dependent mechanism. Moreover, oxidative stress, apoptosis induction and ultrastructural damage increase in a SAR‐dependent manner. However, RF‐EMR does not increase hearing thresholds or induce anxiety.
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While different classes of biological effects of radiation used in modern telecommunications are already confirmed by different experimenters, a lot of contradictory results are also reported. Despite uncertainties, some of the recent results reporting effects show an intriguing agreement between them, although with different biological models and under different laboratory conditions. Such results of exceptional importance and mutual similarity are those reporting DNA damage or oxidative stress induction on reproductive cells of different organisms, resulting in decreased fertility and reproduction. This distinct similarity among results of different researchers makes unlikely the possibility that these results could be wrong. This chapter analyzes and resumes our experimental findings of DNA damage on insect reproductive cells by Global System for Mobile telecommunications (GSM) radiation, compares them with similar recent results on mammalian-human infertility and discusses the possible connection between these findings and other reports regarding tumour induction, symptoms of unwellness, or declines in bird and insect populations. A possible biochemical explanation of the reported effects at the cellular level is attempted. Since microwave radiation is non-ionizing and therefore unable to break chemical bonds, indirect ways of DNA damage are discussed, through enhancement of free radical and reactive oxygen species (ROS) formation, or irregular release of hydrolytic enzymes. Such events can be initiated by alterations of intracellular ionic concentrations after irregular gating of electrosensitive channels on the cell membranes according to the Ion Forced-Vibration theory that we have previously proposed. This biophysical mechanism seems to be realistic, since it is able to explain all of the reported biological effects associated with exposure to electromagnetic fields (EMFs), including the so-called "windows" of increased bioactivity reported for many years but remaining unexplained so far, and recorded also in our recent experiments regarding GSM radiation exposure. The chapter also discusses an important dosimetry issue, regarding the use of Specific Absorption Rate (SAR), a quantity introduced to describe temperature increases within biological tissue (thermal effects), while the recorded biological effects in their vast majority are non-thermal. Finally the chapter attempts to propose some basic precautions and a different way of network design for mobile telephony base station antennas, in order to minimize the exposure of human population and reduce significantly the current exposure limits in order to account for the reported non thermal biological effects.
Chapter
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Different kinds of biological effects of mobile telephony radiation have been already confirmed by different experimenters, while a lot of contradictory results are also reported. In spite of any uncertainty, some of the recent results reporting effects show a distinct agreement between them, although with different biological models and under different laboratory conditions. Such results of exceptional importance and mutual similarity are those reporting DNA damage or oxidative stress induction on reproductive cells of different organisms, resulting in decreased fertility and reproduction. This distinct similarity among results of different experimental studies makes unlikely the possibility that these results could be wrong. This chapter analyzes and resumes our experimental findings of DNA damage on insect reproductive cells by Global System for Mobile telecommunications (GSM) radiations, compares them with similar recent results on mammalian - human infertility and discusses the possible connection between these findings and other reports regarding tumour induction, symptoms of unwellness, or declinations of bird and insect populations. A possible biochemical explanation of the reported effects at the cellular level is attempted. Since microwave radiations are non-ionizing and therefore unable to break chemical bonds, indirect ways of DNA damage are discussed, through enhancement of free radical and reactive oxygen species (ROS) formation, or irregular release of hydrolytic enzymes. Such events can be initiated by alterations of intracellular ionic concentrations after irregular gating of electrosensitive channels on the cell membranes according to the Ion Forced-Vibration mechanism that we have previously proposed. This biophysical mechanism seems to be realistic, since it is able to explain all of the reported biological effects associated with electromagnetic fields (EMFs) exposure, including the so-called "windows" of increased bioactivity reported since many years but remained unexplained so far, and recorded also in our recent experiments in regards to GSM radiation exposure. The chapter discusses also, an important dosimetry issue, regarding the use of Specific Absorption Rate (SAR), a quantity introduced to describe temperature increases within biological tissue (thermal effects), while the vast majority of the recorded biological effects are non-thermal. Finally the chapter attempts to propose so basic precautions and a different way of mobile telephony base station antennas network design, in order to minimize the exposure of human population and reduce significantly the current exposure limits in order to account for the reported non thermal biological effects.
Chapter
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A number of serious non thermal biological effects, ranging from changes in cellular function like proliferation rate changes or gene expression changes to cell death induction, decrease in the rate of melatonin production and changes in electroencephalogram patterns in humans, population declinations of birds and insects, and small but statistically significant increases of certain types of cancer, are attributed in our days to the radiations emitted by mobile telephony antennas of both handsets and base stations. This chapter reviews briefly the most important experimental, clinical and statistical findings and presents more extensively a series of experiments, concerning cell death induction on a model biological system. Mobile telephony radiation is found to decrease significantly and non thermally insect reproduction by up to 60%, after a few minutes daily exposure for only few days. Both sexes were found to be affected. The effect is due to DNA fragmentation in the gonads caused by both types of digital mobile telephony radiation used in Europe, GSM 900MHz, (Global System for Mobile telecommunications), and DCS 1800MHz, (Digital Cellular System). GSM was found to be even more bioactive than DCS, due to its higher intensity under equal conditions. The decrease in reproductive capacity seems to be non-linearly depended on radiation intensity, exhibiting a peak for intensities higher than 200 μW/cm 2 and an intensity "window" around 10μW/cm 2 were it becomes maximum. In terms of the distance from a mobile phone antenna, the intensity of this "window"corresponds under usual conditions to a distance of 20-30 cm. The importance of different parameters of the radiation like intensity, carrier frequency and pulse repetition frequency, in relation to the recorded effects are discussed. Finally, this chapter describes a plausible biophysical and biochemical mechanism which can explain the recorded effects of mobile telephony radiations on living organisms.
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In print since 1972, this seventh edition of Radiobiology for the Radiologist is the most extensively revised to date. It consists of two sections, one for those studying or practicing diagnostic radiology, nuclear medicine and radiation oncology; the other for those engaged in the study or clinical practice of radiation oncology--a new chapter, on radiologic terrorism, is specifically for those in the radiation sciences who would manage exposed individuals in the event of a terrorist event. The 17 chapters in Section I represent a general introduction to radiation biology and a complete, self-contained course especially for residents in diagnostic radiology and nuclear medicine that follows the Syllabus in Radiation Biology of the RSNA. The 11 chapters in Section II address more in-depth topics in radiation oncology, such as cancer biology, retreatment after radiotherapy, chemotherapeutic agents and hyperthermia. Now in full color, this lavishly illustrated new edition is replete with tables and figures that underscore essential concepts. Each chapter concludes with a "summary of pertinent conclusions" to facilitate quick review and help readers retain important information. rica: Lippincott Williams & Wilkins, 2006.
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The book covers all aspects of biological radiation effects. The physical basis is dealt with in some detail, and the effects at the subcellular and the cellular level are discussed, taking into account modern developments and techniques. The effects on the human organism are reviewed, both from the point of view of applications in medicine as well as with regard to radiation hazards (teratogenic, gonadal and carcinogenic effects).