Dosimetric assessment of an exposure system for simulating GSM and WCDMA mobile phone usage

Bahr, A.; Dorn, Hans; Bolz, Thomas

doi:10.1002/bem.20218

Cited by 18 publications

(10 citation statements)

References 13 publications

(15 reference statements)

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“…The upper bound for the field power-specific absorption rate (SAR) for the sample in the resonator was estimated for the assumption that all of the field power fed to the resonator (50 mW in all experiments reported here) is absorbed in the sample. Under these 'worst case' assumptions that significantly overestimate the absorption rate, the SAR value is at most 0.1 W kg 21 , which is considerably lower than the SAR human health safety limit [40].…”

Section: Numerical Calculation Of the Electric Field Distributionmentioning

confidence: 90%

Regulation of endothelial MAPK/ERK signalling and capillary morphogenesis by low-amplitude electric field

Sheikh

Taghian

Hemingway

et al. 2013

J. R. Soc. Interface.

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Low-amplitude electric field (EF) is an important component of woundhealing response and can promote vascular tissue repair; however, the mechanisms of action on endothelium remain unclear. We hypothesized that physiological amplitude EF regulates angiogenic response of microvascular endothelial cells via activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway. A custom set-up allowed non-thermal application of EF of high (7.5 GHz) and low (60 Hz) frequency. Cell responses following up to 24 h of EF exposure, including proliferation and apoptosis, capillary morphogenesis, vascular endothelial growth factor (VEGF) expression and MAPK pathways activation were quantified. A db/db mouse model of diabetic wound healing was used for in vivo validation. High-frequency EF enhanced capillary morphogenesis, VEGF release, MEK-cRaf complex formation, MEK and ERK phosphorylation, whereas no MAPK/JNK and MAPK/p38 pathways activation was observed. The endothelial response to EF did not require VEGF binding to VEGFR2 receptor. EF-induced MEK phosphorylation was reversed in the presence of MEK and Ca 2þ inhibitors, reduced by endothelial nitric oxide synthase inhibition, and did not depend on PI3K pathway activation. The results provide evidence for a novel intracellular mechanism for EF regulation of endothelial angiogenic response via frequency-sensitive MAPK/ERK pathway activation, with important implications for EF-based therapies for vascular tissue regeneration.

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Section: Numerical Calculation Of the Electric Field Distributionmentioning

confidence: 90%

Regulation of endothelial MAPK/ERK signalling and capillary morphogenesis by low-amplitude electric field

Sheikh

Taghian

Hemingway

et al. 2013

J. R. Soc. Interface.

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“…In most cases real GSM phones were directly attached to the head by special holders or tapes and the phones were either operated at a defined power control level [Braune et al, 1998[Braune et al, , 2002Koivisto et al, 2000aKoivisto et al, ,b, 2001Krause et al, 2000aKrause et al, ,b, 2004Haarala et al, 2003aHaarala et al, ,b, 2004Haarala et al, , 2005Maier et al, 2004;Preece et al, 2005] or the phones' antennas were fed via cable from an external signal generation unit [Freude et al, , 2000Eulitz et al, 1998]. Most recently a new head exposure concept was published by Bahr et al [2006]. They developed a small and lightweight planar antenna which could be directly worn at the subject's ear.…”

Section: Introductionmentioning

confidence: 99%

New head exposure system for use in human provocation studies with EEG recording during GSM900‐ and UMTS‐like exposure

Schmid

Cecil

Goger

et al. 2007

Bioelectromagnetics

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A new head exposure system for double blinded human provocation studies, which requires EEG recording during exposure with GSM900- and UMTS-like signals has been developed and dosimetrically evaluated. The system uses planar patch antennas fixed at 65 mm distance from the subject's head by a special headset, which provides minimum impairment of the test subjects and ensures an almost constant position of the antennas with respect to the head, even in case of head movements. Compared to exposure concepts operating small antennas in close proximity to the head, the concept of planar antennas at a certain distance from the head produces a much more homogeneous SAR distribution in the temporal and parietal lobe of the brain. At the same time the resulting uncertainty of exposure due to variations in head size, variations of the dielectric properties of tissues and unavoidable small changes of the antenna's position with respect to the head, is reduced to the order of approximately 3 dB, which is a significant improvement to comparable head exposure systems reported in literature in the past. To avoid electromagnetic interference on the EEG recording caused by the incident RF-field an appropriate double-shielded filter circuit has been developed. Furthermore, the effect of the presence of the sintered Ag/AgCl EEG electrodes and electrode wires on the SAR distribution inside the head has been investigated and was found to be minimal if the electrode wires are arranged orthogonal to the incident electric field vector. EEG electrode arrangement parallel to the incident field vector, however, might cause drastic changes in the SAR distribution inside the head.

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“…3). The outer dimensions of the antenna remained identical to those in Bahr et al [2006]. The antenna was built on a 1.5 mm thick RO4003 substrate (Rogers, Chandler, AZ).…”

Section: Antenna Designmentioning

confidence: 99%

Design and dosimetric analysis of a 385 MHz TETRA head exposure system for use in human provocation studies

Schmid

Bolz

Überbacher

et al. 2012

Bioelectromagnetics

Self Cite

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A new head exposure system for double-blind provocation studies investigating possible effects of terrestrial trunked radio (TETRA)-like exposure (385 MHz) on central nervous processes was developed and dosimetrically analyzed. The exposure system allows localized exposure in the temporal brain, similar to the case of operating a TETRA handset at the ear. The system and antenna concept enables exposure during wake and sleep states while an electroencephalogram (EEG) is recorded. The dosimetric assessment and uncertainty analysis yield high efficiency of 14 W/kg per Watt of accepted antenna input power due to an optimized antenna directly worn on the subject's head. Beside sham exposure, high and low exposure at 6 and 1.5 W/kg (in terms of maxSAR10g in the head) were implemented. Double-blind control and monitoring of exposure is enabled by easy-to-use control software. Exposure uncertainty was rigorously evaluated using finite-difference time-domain (FDTD)-based computations, taking into account anatomical differences of the head, the physiological range of the dielectric tissue properties including effects of sweating on the antenna, possible influences of the EEG electrodes and cables, variations in antenna input reflection coefficients, and effects on the specific absorption rate (SAR) distribution due to unavoidable small variations in the antenna position. This analysis yielded a reasonable uncertainty of <±45% (max to min ratio of 4.2 dB) in terms of maxSAR10g in the head and a variability of <±60% (max to min ratio of 6 dB) in terms of mass-averaged SAR in different brain regions, as demonstrated by a brain region-specific absorption analysis.

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Dosimetric assessment of an exposure system for simulating GSM and WCDMA mobile phone usage

Cited by 18 publications

References 13 publications

Regulation of endothelial MAPK/ERK signalling and capillary morphogenesis by low-amplitude electric field

Regulation of endothelial MAPK/ERK signalling and capillary morphogenesis by low-amplitude electric field

New head exposure system for use in human provocation studies with EEG recording during GSM900‐ and UMTS‐like exposure

Design and dosimetric analysis of a 385 MHz TETRA head exposure system for use in human provocation studies

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