de Salles AA, Bulla G, Rodriguez CE. · 2006
Researchers simulated Specific Absorption Rate (SAR) in adult and child head models using the Finite Difference Time Domain method at 850 MHz and 1850 MHz. They used realistic head models with fitted electromagnetic parameters and tested microstrip and quarter-wavelength monopole antennas. The 1g-SAR for children was higher than for adults, exceeding 60% higher in the 10-year-old model. Results were compared with international recommendations.
Paulraj R, Behari J · 2006
The control group was sham irradiated. The study revealed a statistically significant decrease in PKC activity in the hippocampus compared to the rest of the brain and controls. Electron microscopy showed an increase in glial cell population in the exposed group.
Capri M et al. · 2006
Researchers exposed human peripheral blood mononuclear cells from young and elderly donors to radiofrequency radiation at 1,800 MHz and a Specific Absorption Rate of 2 W/kg, with or without mitogenic stimulation. However, RF exposure produced a slight but significant downregulation of CD95 expression in stimulated CD4+ T lymphocytes from elderly donors only.
Paulraj R, Behari J. · 2006
Researchers exposed 35-day-old male Wistar rats to microwave radiation at 2.45 GHz and 16.5 GHz for 35 days to study effects on developing rat brain. After exposure, the researchers measured DNA single strand breaks in brain tissue using micro gel electrophoresis (comet assay), with fifty cells from each slide and two slides per animal observed. The study found a statistically significant increase (p < 0.001) in DNA single strand breaks in the brain cells of exposed rats.
Preece AW et al. · 2005
Researchers tested 18 children aged 10 to 12 years using a randomized three-way crossover design with exposures of 0, 0.025, or 0.25 W from a Nokia 3110 handset. Baseline reaction times were considerably slower than in adults. There was a tendency for shorter reaction times during exposure, most marked for simple reaction time, but no effects reached statistical significance after Bonferroni correction.
Kuribayashi M et al. · 2005
Researchers investigated possible effects of 1439 MHz electromagnetic near field exposure on the blood-brain barrier in immature (4 weeks old) and young (10 weeks old) rats. Expression of the three genes was not pathologically changed by EMF at any exposure level or age, and vascular permeability measured with FITC-dextran FD20 was not affected. The findings suggest that local head exposure to 1439 MHz EMF exerts no adverse effects on the BBB in immature and young rats.
Iudice A et al. · 2005
Twenty-three young healthy participants completed a 10 km simulated drive under four counterbalanced conditions: alcohol alone, alcohol with 19 h wakefulness, alcohol with 24 h wakefulness, and sober. The combination of alcohol and 24 h wakefulness produced the highest driving impairment, significantly greater than alcohol alone. Alcohol with 19 h wakefulness significantly affected only the time-to-collision measure, while alcohol alone in rested conditions did not significantly change any study measure.
Haarala C et al. · 2005
Researchers exposed 32 children aged 10-14 to a 902 MHz GSM mobile phone in active and inactive conditions while they performed cognitive tests. Statistical analysis showed no significant differences in reaction times or accuracy between the phone-on and phone-off conditions across all tests. The authors concluded that a standard mobile phone has no effect on children's cognitive function as measured by response speed and accuracy.
Christ A, Kuster N. · 2005
The study investigates differences in RF energy absorption in the heads of adults and children. It discusses absorption mechanisms, tissue parameters, the effect of the pinna, and uncertainties in head models based on spheroids, scaled adult heads, and MRI data of children. The review concludes that energy exposure does not increase due to smaller heads, but identifies open issues regarding dielectric tissue parameters and pinna thickness.
Keshvari J, Lang S. · 2005
Researchers used the finite-difference time-domain (FDTD) computational method to calculate specific absorption rate (SAR) in anatomically correct adult and child head models exposed to a half-wave dipole at 900, 1800, and 2450 MHz. The ear and eye regions were studied because they represent realistic exposure scenarios for mobile wireless communication devices.
Bit-Babik et al. · 2005
The study used FDTD computations to calculate locally averaged SAR in anatomically correct adult and child head models with the IEEE standard averaging algorithm. Peak local average SAR over 1 g and 10 g of tissue and electromagnetic energy penetration depths were about the same across all head models under the same exposure conditions. Child head models were created by linear scaling of the adult model and by transforming adult models based on children's external head shapes, with tissue properties kept the same. Modeling and experimental measurements also used three spheres filled with tissue-equivalent mixture to approximate heads of increasing size.
Huber R et al. · 2005
Researchers investigated the effects of radio frequency electromagnetic fields similar to those emitted by mobile phones on waking regional cerebral blood flow in 12 healthy young men. Positron emission tomography scans were taken after 30 min unilateral head exposure to pulse-modulated 900 MHz RF EMF, and a sham control condition was also included. Only the 'handset-like' signal, which had stronger low-frequency components, increased relative cerebral blood flow in the dorsolateral prefrontal cortex on the side of exposure; the 'base-station-like' signal did not.
Capri M et al. · 2004
Researchers studied whether prolonged in vitro exposure to 1800 MHz radiofrequency could affect human peripheral blood mononuclear cells from young and elderly donors by altering apoptosis, mitochondrial membrane potential, and heat shock protein 70 levels. Three GSM signal modulations (Basic, DTX, and Talk) were applied at specific absorption rates of 1.4 and 2.0 W kg−1. Endpoints were analyzed both with and without the apoptosis-inducing agent 2-deoxy-D-ribose. No significant difference was found between RF-exposed and sham-exposed cells for any endpoint. The 1800 MHz RF did not induce apoptosis on its own, did not alter apoptosis triggered by an agent, and did not change mitochondrial function or HSP 70 expression.
Martinez-Burdalo M, Martin A, Anguiano M, Villar R · 2004
Peak SAR1g and SAR10g trended downwards as head size decreased. The percentage of energy absorbed in the brain increased with smaller head size. SAR distributions in eyes were very similar between full-size and scaled models.
Paulraj R, Behari J · 2004
Protein kinase C activity was measured in whole brain, hippocampus, and whole brain minus hippocampus after exposure. A significant decrease in enzyme level was observed in exposed rats compared to sham-exposed rats.
Kramarenko AV, Tan U. · 2003
Researchers used a 16-channel telemetric electroencephalograph to record EEG changes during exposure of the human skull to EMF from a mobile phone. During exposure, median frequency increased in areas close to the antenna after 10-15 seconds, and slow-wave activity (2.5-6.0 Hz) appeared in contralateral frontal and temporal areas after 20-40 seconds. The slow waves lasted about one second and repeated every 15-20 seconds, and both the slow-wave activity and increased median frequency disappeared after the phone was turned off.
Moneda AP, Ioannidou MP, Chrissoulidis DP. · 2003
Researchers used a versatile eccentric-spheres model of the human head to investigate radio-wave absorption. Specific absorption rate maps showed hot spots in the eyes and near the center of the brain. Numerical results were presented for total, percentage, and gram-specific absorption using an exact analytical solution. The model focused on the brain and eyes of an adult or infant head.
Anderson V. · 2003
The study aimed to examine the scale and significance of differences in peak specific energy absorption rate (SAR) in the brains of children and adults exposed to radiofrequency emissions from mobile phones. Model analyses using a three-layered spherical head exposed to a dipole at 900 MHz showed that peak brain 10 g averaged SAR in 4, 8, 12, and 16 year olds increased by factors of 1.31, 1.23, 1.15, and 1.07 compared to an average adult. The researchers concluded that the relatively small scale of these increases does not warrant special precautionary measures for child mobile phone users.
Takahashi S et al. · 2002
Researchers investigated the mutagenic potential of 1.5 GHz electromagnetic near fields using brain tissues of Big Blue mice. Male BBM were locally exposed to EMF in the head region at 2.0, 0.67, and 0 W/kg specific absorption rate for 90 min/day, 5 days/week, for 4 weeks. There was no significant variation in the frequency of independent mutations of the lacI transgene in the brains. Deletion mutations were slightly increased in both the high and low EMF exposure groups as compared with the sham-exposed group, but the differences were not statistically significant.
Richter ED, Berman T, Levy O · 2002
The authors reported on five young patients who developed brain tumors within 10 years of initial occupational radar exposure. Four of the patients were less than 30 years old at the time of diagnosis.
Braune S, Riedel A, Schulte-Monting J, Raczek J. · 2002
The study investigated the hypothesis that exposure to EMFs can increase sympathetic vasoconstrictor activity. Forty healthy young males and females underwent a single-blind, placebo-controlled protocol on two different days with randomized EMF and placebo periods. The EMF exposure was a GSM-like signal at 900 MHz, pulsed with 217 Hz, 2 W, delivered by a mobile phone on the right side of the head. Blood pressure, heart rate, cutaneous capillary perfusion, and serum levels of norepinephrine, epinephrine, cortisol, and endothelin were measured. Systolic and diastolic blood pressure increased about 5 mmHg during the protocol, but the changes were independent of EMF exposure.
Paulraj R, Behari J · 2002
Researchers exposed 35-day-old Wistar rats to low-level continuous 2.45 GHz microwaves for 2 hr/day over 35 days at a power density of 0.34 mW/cm2 with a specific absorption rate of 0.1 W/kg. Exposed rats showed a significant increase in calcium ion efflux and ornithine decarboxylase activity and a significant decrease in calcium-dependent protein kinase activity in brain tissue. The authors suggested that the radiation affects membrane-bound enzymes linked to cell proliferation and differentiation, indicating a possible tumor-promoting role.
Peyman A, Rezazadeh AA, Gabriel C · 2001
Researchers measured dielectric properties of ten rat tissues at six ages from 130 MHz to 10 GHz. Results showed a general decrease in dielectric properties with age. The decrease was more apparent in brain, skull, and skin tissues than in abdominal tissues. The variation was attributed to changes in water content and organic composition.
Wainwright P, · 2000
Researchers developed a finite element thermal model of the head to calculate temperature rises in the brain from cellular telephone radiation. The model used a 1 mm resolution MRI dataset segmented into ten tissue types and a finite element mesh generated with an automatic tetrahedral mesh generator. The model included natural metabolic heat production and power absorbed from the electromagnetic field, with SAR derived from a finite difference time domain model coupled to a model mobile phone. For publicly available equipment, the maximum temperature rise in the brain was about 0.1 °C. The steady-state temperature distribution was calculated using the Pennes bioheat equation.
Huber R et al. · 2000
Researchers exposed healthy young male subjects for 30 minutes to EMF at 900 MHz and a spatial peak specific absorption rate of 1 W/kg during the waking period before sleep. Compared with a sham exposure control condition, EEG spectral power during non-rapid eye movement sleep was increased, with the maximum rise in the 9.75-11.25 Hz and 12.5-13.25 Hz bands during the initial part of sleep. The researchers concluded that the changes of brain function induced by pulsed high-frequency EMF outlast the exposure period.
