Theoretical evaluation of dielectric absorption of microwave energy at the scale of nucleic acids

Vanderstraeten, Jacques; Vorst, André A Vander

doi:10.1002/bem.20001

Cited by 7 publications

(3 citation statements)

References 52 publications

(85 reference statements)

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“…Yet, the specificity of MW heating is its in-core volumetric nature, and most authors agree about a possible role for energy absorption at the precise place of the reacting molecules. When considering, for example, the local SAR value in vivo at the interface between free DNA and the surrounding solution, a very preferential MW energy absorption exists at that place because of the particularly high concentrations of bound water molecules and counterions at this interface (Vanderstraeten and Vander Vorst 2004). As a possible explanation for the phenomenon of MW-assisted chemistry, and based on a quantum mechanical model of an S N 2 reaction, Kalhori et al (2002) suggested that bound water molecules could confer vibrational modes in the low-GHz frequency range to solvated reaction complexes.…”

Section: Discussionmentioning

confidence: 99%

Gene and Protein Expression following Exposure to Radiofrequency Fields from Mobile Phones

Vanderstraeten

Verschaeve²

2008

Environ Health Perspect

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BackgroundSince 1999, several articles have been published on genome-wide and/or proteome-wide response after exposure to radiofrequency (RF) fields whose signal and intensities were similar to or typical of those of currently used mobile telephones. These studies were performed using powerful high-throughput screening techniques (HTSTs) of transcriptomics and/or proteomics, which allow for the simultaneous screening of the expression of thousands of genes or proteins.ObjectivesWe reviewed these HTST-based studies and compared the results with currently accepted concepts about the effects of RF fields on gene expression. In this article we also discuss these last in light of the recent concept of microwave-assisted chemistry.DiscussionTo date, the results of HTST-based studies of transcriptomics and/or proteomics after exposure to RF fields relevant to human exposure are still inconclusive, as most of the positive reports are flawed by methodologic imperfections or shortcomings. In addition, when positive findings were reported, no precise response pattern could be identified in a reproducible way. In particular, results from HTST studies tend to exclude the role of a cell stressor for exposure to RF fields at nonthermal intensities. However, on the basis of lessons from microwave-assisted chemistry, we can assume that RF fields might affect heat-sensitive gene or protein expression to an extent larger than would be predicted from temperature change only. But in all likelihood, this would concern intensities higher than those relevant to usual human exposure.ConclusionsThe precise role of transcriptomics and proteomics in the screening of bioeffects from exposure to RF fields from mobile phones is still uncertain in view of the lack of positively identified phenotypic change and the lack of theoretical, as well as experimental, arguments for specific gene and/or protein response patterns after this kind of exposure.

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Section: Discussionmentioning

confidence: 99%

Gene and Protein Expression following Exposure to Radiofrequency Fields from Mobile Phones

Vanderstraeten

Verschaeve²

2008

Environ Health Perspect

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“…As radiofrequency (RF) mobile phones have become a part of daily life, possible risks related to exposure to RF electromagnetic (EM) fields of mobile phones have been studied from several aspects, from cell level to macroscopic effects such as local heating , Riu and Foster 1999, Repacholi 2001, Vanderstraeten and van der Vorst 2004. Most of the experimental research and numerical calculations have focused on estimating specific absorption rate (SAR, W kg −1 ) and local heating.…”

Section: Introductionmentioning

confidence: 99%

Interaction of mobile phones with superficial passive metallic implants

et al. 2005

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The dosimetry of exposure to radiofrequency (RF) electromagnetic (EM) fields of mobile phones is generally based on the specific absorption rate (SAR, W kg(-1)), which is the electromagnetic energy absorbed in the tissues per unit mass and time. In this study, numerical methods and modelling were used to estimate the effect of a passive, metallic (conducting) superficial implant on a mobile phone EM field and especially its absorption in tissues in the near field. Two basic implant models were studied: metallic pins and rings in the surface layers of the human body near the mobile phone. The aim was to find out 'the worst case scenario' with respect to energy absorption by varying different parameters such as implant location, orientation, size and adjacent tissues. Modelling and electromagnetic field calculations were carried out using commercial SEMCAD software based on the FDTD (finite difference time domain) method. The mobile phone was a 900 MHz or 1800 MHz generic phone with a quarter wave monopole antenna. A cylindrical tissue phantom models different curved sections of the human body such as limbs or a head. All the parameters studied (implant size, orientation, location, adjacent tissues and signal frequency) had a major effect on the SAR distribution and in certain cases high local EM fields arose near the implant. The SAR values increased most when the implant was on the skin and had a resonance length or diameter, i.e. about a third of the wavelength in tissues. The local peak SAR values increased even by a factor of 400-700 due to a pin or a ring. These highest values were reached in a limited volume close to the implant surface in almost all the studied cases. In contrast, without the implant the highest SAR values were generally reached on the skin surface. Mass averaged SAR(1 g) and SAR(10 g) values increased due to the implant even by a factor of 3 and 2, respectively. However, at typical power levels of mobile phones the enhancement is unlikely to be problematic.

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“…In a second approach, two electrodes were inserted into cell suspensions and the corresponding impedance data were interpreted into both electrical parameters of cell membranes and nucleus [15,17,18,21,24,25,28,29,31,34,36,41,42,43,44,45]. Based on this approach, C ne and R ne of nuclei derived from mouse spleen lymphocytes, human Jurkat cells and rat H9C2 cells were quantified as 0.62 μF/cm 2 and 0.07 Ω·cm 2 [15], 1.19 ± 0.14 μF/cm 2 and 0.21 ± 0.02 Ω·cm 2 [36], 0.22 ± 0.05 μF/cm 2 and 7.25 ± 0.68 Ω·cm 2 [34], respectively.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Single-Nucleus Electrical Properties by Microfluidic Constriction Channel

et al. 2019

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As key bioelectrical markers, equivalent capacitance (Cne, i.e., capacitance per unit area) and resistance (Rne, i.e., resistivity multiply thickness) of nuclear envelopes have emerged as promising electrical indicators, which cannot be effectively measured by conventional approaches. In this study, single nuclei were isolated from whole cells and trapped at the entrances of microfluidic constriction channels, and then corresponding impedance profiles were sampled and translated into single-nucleus Cne and Rne based on a home-developed equivalent electrical model. Cne and Rne of A549 nuclei were first quantified as 3.43 ± 1.81 μF/cm2 and 2.03 ± 1.40 Ω·cm2 (Nn = 35), which were shown not to be affected by variations of key parameters in nuclear isolation and measurement. The developed approach in this study was also used to measure a second type of nuclei, producing Cne and Rne of 3.75 ± 3.17 μF/cm2 and 1.01 ± 0.70 Ω·cm2 for SW620 (Nn = 17). This study may provide a new perspective in single-cell electrical characterization, enabling cell type classification and cell status evaluation based on bioelectrical markers of nuclei.

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Theoretical evaluation of dielectric absorption of microwave energy at the scale of nucleic acids

Cited by 7 publications

References 52 publications

Gene and Protein Expression following Exposure to Radiofrequency Fields from Mobile Phones

Gene and Protein Expression following Exposure to Radiofrequency Fields from Mobile Phones

Interaction of mobile phones with superficial passive metallic implants

Characterization of Single-Nucleus Electrical Properties by Microfluidic Constriction Channel

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