Mechanisms for interaction between RF fields and biological tissue

Challis, L. J.

doi:10.1002/bem.20119

Cited by 191 publications

(139 citation statements)

References 40 publications

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“…However, a thermal mechanism should be rejected taking into account that: (1) the distance between the antenna and the head drastically reduces the absorbed power (Schö nborn et al, 1999); (2) increase of skin temperature would be easily dissipated through the blood flow (Van Leeuwen et al, 1999); and (3) near-infrared light penetrates through the brain at least 1.5 cm in-depth, in which temperature changes are far below the danger level (Wang and Fujiwara, 1999;Bernardi et al, 2000). Thus, several nonthermal mechanisms could be involved, such as: (1) proteins conformational variations resulting in proteins functional changes; (2) modifications in the binding of ligands, such as Ca + + to cell receptors, also resulting in a changed receptor function; (3) absorption of RF energy by the vibrational states of biologic components, such as microtubules; (4) enhanced attraction amongst cells (the pearl-chain effect); and (5) demodulation of a modulated RF signal, producing extremely lowfrequency electric fields (for a review, see Challis, 2005). Given the short-term effects observed in this study as a consequence of an acute exposure lasting 40 mins, conclusions about long-term health consequences of the RF-EMF exposure are premature and need more-in-depth epidemiologic investigations, particularly regarding long-term and repeated exposures over several years.…”

Section: Discussionmentioning

confidence: 99%

Acute Mobile Phones Exposure Affects Frontal Cortex Hemodynamics as Evidenced by Functional Near-Infrared Spectroscopy

Curcio

Ferrara

Limongi

et al. 2009

J Cereb Blood Flow Metab

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This study aimed to evaluate by functional near-infrared spectroscopy (fNIRS), the effects induced by an acute exposure (40 mins) to a GSM (Global System for Mobile Communications) signal emitted by a mobile phone (MP) on the oxygenation of the frontal cortex. Eleven healthy volunteers underwent two sessions (Real and Sham exposure) after a crossover, randomized, double-blind paradigm. The whole procedure lasted 60 mins: 10-mins baseline (Bsl), 40-mins (Exposure), and 10-mins recovery (Post-Exp). Together with frontal hemodynamics, heart rate, objective and subjective vigilance, and self-evaluation of subjective symptoms were also assessed. The fNIRS results showed a slight influence of the GSM signal on frontal cortex, with a linear increase in [HHb] as a function of time in the Real exposure condition (F 4,40 = 2.67; P = 0.04). No other measure showed any GSM exposure-dependent changes. These results suggest that fNIRS is a convenient tool for safely and noninvasively investigating the cortical activation in MP exposure experimental settings. Given the short-term effects observed in this study, the results should be confirmed on a larger sample size and using a multichannel instrument that allows the investigation of a wider portion of the frontal cortex.

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Section: Discussionmentioning

confidence: 99%

Acute Mobile Phones Exposure Affects Frontal Cortex Hemodynamics as Evidenced by Functional Near-Infrared Spectroscopy

Curcio

Ferrara

Limongi

et al. 2009

J Cereb Blood Flow Metab

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“…In Section 3, this will be studied in more detail for various wave forms. The initial condition may be altered to the gauge invariant wave function (6). It can be checked that the obtained expectation values do not change.…”

Section: Formalism and Plasmamentioning

confidence: 99%

“…There is, of course, a vast amount of literature on biological effects of electromagnetic radiation. Some more recent examples are [3][4][5][6][7]. It is not the purpose of this study to discuss these papers; a recent review, including many references, is given in [8].…”

Section: Introductionmentioning

confidence: 99%

Ion Plasma Responses to External Electromagnetic Fields

Naus

2010

SRX Physics

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The response of ion plasmas to external radiation fields is investigated in a quantum mechanical formalism. We focus on the total electric field within the plasma. For general bandpass signals three frequency regions can be distinguished in terms of the plasma frequency. For low frequencies, the external field is shielded. For high frequencies, the field is not modified. Resonant behavior of the plasma appears for frequencies near the plasma frequency: large internal electric fields and induced currents are present. These effects may be relevant for biological systems. The model is therefore extended to a two-species plasma and additional interactions are studied. The response is not essentially altered. To make the models more realistic, a so-called bath is included. In the weak coupling approximation the resonance frequency is shifted and some damping occurs. Finite temperature effects on the electric field are absent. The energy of the system, however, depends on temperature.

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“…This has led to different defined levels of analysis, i.e. human level, tissue level, cell level and ionic level [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Calibration model for detection of potential demodulating behaviour in biological media exposed to RF energy

See

Abd‐Alhameed

Ghani

et al. 2017

IET Science, Measurement & Technology

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Abstract-Potential demodulating ability in biological tissue exposed to Radio Frequency (RF) signals intrinsically requires an unsymmetrical diode-like nonlinear response in tissue samples. This may be investigated by observing possible generation of the second harmonic in a cavity resonator designed to have fundamental and second harmonic resonant frequencies with collocated antinodes. Such a response would be of interest as being a mechanism that could enable demodulation of information-carrying waveforms having modulating frequencies in ranges that could interfere with cellular processes. Previous work has developed an experimental system to test for such responses: the present work reports an electric circuit model devised to facilitate calibration of any putative nonlinear RF energy conversion occurring within a nonlinear test-piece inside the cavity. The method is validated computationally and experimentally using a well-characterised nonlinear device. The variations of the reflection coefficients of the fundamental and second harmonic responses of the cavity due to adding nonlinear and lossy material are also discussed. The proposed model demonstrates that the sensitivity of the measurement equipment plays a vital role in deciding the required input power to detect any second harmonic signal, which is expected to be very weak. The model developed here enables the establishment of a lookup table giving the level of the second harmonic signal in the detector as a function of the specific input power applied in a measurement. Experimental results are in good agreement with the simulated results.

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Mechanisms for interaction between RF fields and biological tissue

Cited by 191 publications

References 40 publications

Acute Mobile Phones Exposure Affects Frontal Cortex Hemodynamics as Evidenced by Functional Near-Infrared Spectroscopy

Acute Mobile Phones Exposure Affects Frontal Cortex Hemodynamics as Evidenced by Functional Near-Infrared Spectroscopy

Ion Plasma Responses to External Electromagnetic Fields

Calibration model for detection of potential demodulating behaviour in biological media exposed to RF energy

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