| 1. |
- Augustine, Robin, 1982-
(författare)
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Near-field dosimetry for the millimeter-wave exposure of human cells in vitro
- 2012
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Ingår i: Bioelectromagnetics. - 0197-8462 .- 1521-186X. ; , s. 55-64
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Tidskriftsartikel (refereegranskat)abstract
- Due to the expected mass deployment of millimeter-wave wireless technologies, thresholds of potential millimeter-wave-induced biological and health effects should be carefully assessed. The main purpose of this study is to propose, optimize, and characterize a near-field exposure configuration allowing illumination of cells in vitro at 60 GHz with power densities up to several tens of mW/cm(2) . Positioning of a tissue culture plate containing cells has been optimized in the near-field of a standard horn antenna operating at 60 GHz. The optimal position corresponds to the maximal mean-to-peak specific absorption rate (SAR) ratio over the cell monolayer, allowing the achievement of power densities up to 50 mW/cm(2) at least. Three complementary parameters have been determined and analyzed for the exposed cells, namely the power density, SAR, and temperature dynamics. The incident power density and SAR have been computed using the finite-difference time-domain (FDTD) method. The temperature dynamics at different locations inside the culture medium are measured and analyzed for various power densities. Local SAR, determined based on the initial rate of temperature rise, is in a good agreement with the computed SAR (maximal difference of 5%). For the optimized exposure setup configuration, 73% of cells are located within the ±3 dB region with respect to the average SAR. It is shown that under the considered exposure conditions, the maximal power density, local SAR, and temperature increments equal 57 mW/cm(2) , 1.4 kW/kg, and 6 °C, respectively, for the radiated power of 425 mW.
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| 2. |
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| 3. |
- Baste, Valborg, et al.
(författare)
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Radiofrequency exposure on fast patrol boats in the Royal Norwegian Navy-an approach to a dose assessment.
- 2010
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Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 31:5, s. 350-360
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Tidskriftsartikel (refereegranskat)abstract
- Epidemiological studies related to radiofrequency (RF) electromagnetic fields (EMF) have mainly used crude proxies for exposure, such as job titles, distance to, or use of different equipment emitting RF EMF. The Royal Norwegian Navy (RNoN) has measured RF field emitted from high-frequency antennas and radars on several spots where the crew would most likely be located aboard fast patrol boats (FPB). These boats are small, with short distance between the crew and the equipment emitting RF field. We have described the measured RF exposure aboard FPB and suggested different methods for calculations of total exposure and annual dose. Linear and spatial average in addition to percentage of ICNIRP and squared deviation of ICNIRP has been used. The methods will form the basis of a job exposure matrix where relative differences in exposure between groups of crew members can be used in further epidemiological studies of reproductive health. Bioelectromagnetics, 2010. (c) 2010 Wiley-Liss, Inc.
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| 4. |
- Belyaev, IY, et al.
(författare)
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Exposure of rat brain to 915 MHz GSM microwaves induces changes in gene expression but not double stranded DNA breaks or effects on chromatin conformation
- 2006
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Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 27:4, s. 295-306
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Tidskriftsartikel (refereegranskat)abstract
- We investigated whether exposure of rat brain to microwaves (MWs) of global system for mobile communication (GSM) induces DNA breaks, changes in chromatin conformation and in gene expression. An exposure installation was used based on a test mobile phone employing a GSM signal at 915 MHz, all standard modulations included, output power level in pulses 2 W, specific absorption rate (SAR) 0.4 mW/g. Rats were exposed or sham exposed to MWs during 2 h. After exposure, cell suspensions were prepared from brain samples, as well as from spleen and thymus. For analysis of gene expression patterns, total RNA was extracted from cerebellum. Changes in chromatin conformation, which are indicative of stress response and genotoxic effects, were measured by the method of anomalous viscosity time dependencies (AVTD). DNA double strand breaks (DSBs) were analyzed by pulsed-field gel electrophoresis (PFGE). Effects of MW exposure were observed on neither conformation of chromatin nor DNA DSBs. Gene expression profiles were obtained by Affymetrix U34 GeneChips representing 8800 rat genes and analyzed with the Affymetrix Microarray Suite (MAS) 5.0 software. In cerebellum from all exposed animals, I I genes were upregulated in a range of 1.34-2.74 fold and one gene was downregulated 0.48-fold (P <.0025). The induced genes encode proteins with diverse functions including neurotransmitter regulation, blood-brain barrier (BBB), and melatonin production. The data shows that GSM MWs at 915 MHz did not induce PFGE-detectable DNA double stranded breaks or changes in chromatin conformation, but affected expression of genes in rat brain cells. Bioelectromagnetics 27:295-306, 2006. (c) 2006 Wiley-Liss, Inc.
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| 5. |
- Belyaev, I Y, et al.
(författare)
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915 MHz microwaves and 50 Hz magnetic field affect chromatin conformation and 53BP1 foci in human lymphocytes from hypersensitive and healthy persons
- 2005
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Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 26:3, s. 173-184
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Tidskriftsartikel (refereegranskat)abstract
- We used exposure to microwaves from a global system for mobile communication (GSM) mobile phone (915 MHz, specific absorption rate (SAR) 37 mW/kg) and power frequency magnetic field (50 Hz, 15 mu T peak value) to investigate the response of lymphocytes from healthy subjects and from persons reporting hypersensitivity to electromagnetic field (EMF). The hypersensitive and healthy donors were matched by gender and age and the data were analyzed blind to treatment condition. The changes in chromatin conformation were measured with the method of anomalous viscosity time dependencies (AVTD). 53BP1 protein, which has been shown to colocalize in foci with DNA double strand breaks (DSBs), was analyzed by immunostaining in situ. Exposure at room temperature to either 915 MHz or 50 Hz resulted in significant condensation of chromatin, shown as AVTD changes, which was similar to the effect of heat shock at 41 degrees C. No significant differences in responses between normal and hypersensitive subjects were detected. Neither 915 MHz nor 50 Hz exposure induced 53BP1 foci. On the contrary, a distinct decrease in background level of 53BP1 signaling was observed upon these exposures as well as after heat shock treatments. This decrease correlated with the AVTD data and may indicate decrease in accessibility of 53BP1 to antibodies because of stress-induced chromatin condensation. Apoptosis was determined by morphological changes and by apoptotic fragmentation of DNA as analyzed by pulsed-field gel electrophoresis (PFGE). No apoptosis was induced by exposure to 50 Hz and 915 MHz microwaves. In conclusion, 50 Hz magnetic field and 915 MHz microwaves under specified conditions of exposure induced comparable responses in lymphocytes from healthy and hypersensitive donors that were similar but not identical to stress response induced by heat shock.
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| 6. |
- Belyaev, Igor Y, et al.
(författare)
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Microwaves From UMTS/GSM Mobile Phones Induce Long-Lasting Inhibition of 53BP1/gamma-H2AX DNA Repair Foci in Human Lymphocytes
- 2009
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Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 30:2, s. 129-141
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Tidskriftsartikel (refereegranskat)abstract
- We have recently described frequency-dependent effects of mobile phone microwaves (MWs) of global system for mobile communication (GSM) on human lymphocytes from persons reporting hypersensitivity to electromagnetic fields and healthy persons. Contrary to GSM, universal global telecommunications system (UMTS) mobile phones emit wide-band MW signals. Hypothetically, UMTS MWs may result in higher biological effects compared to GSM signal because of eventual "effective" frequencies within the wideband. Here, we report for the first time that UMTS MWs affect chromatin and inhibit formation of DNA double-strand breaks co-localizing 53BP1/gamma-H2AX DNA repair foci in human lymphocytes from hypersensitive and healthy persons and confirm that effects of GSM MWs depend oil carrier frequency. Remarkably, the effects of MWs on 53BP1/gamma-H2AX foci persisted up to 72 h following exposure of cells, even longer than the stress response following heat shock. The data are in line with the hypothesis that the type of signal, UMTS MWs, may have higher biological efficiency and possibly larger health risk effects compared to GSM radiation emissions. No significant differences in effects between groups of healthy and hypersensitive subjects were observed, except for the effects of UNITS MWs and GSM-915 MHz MWs on the formation of the DNA repair foci, which were different for hypersensitive (P < 0.02[53BP1)//0.01[gamma-H2AX]) but not for control subjects (P > 0.05). The non-parametric statistics used here did not indicate specificity of the differences revealed between the effects of GSM and UMTS MWs oil cells from hypersensitive subjects and more data are needed to study the nature of these differences, Bioelectromagnetics 30: 129-141, 2009. (C) 2008 Wiley-Liss, Inc.
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| 7. |
- Dabek, Marta, et al.
(författare)
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Effect of the electrical currents generated by the intestinal smooth muscle layers on pancreatic enzyme activity: An in vitro study
- 2007
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Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 28:4, s. 275-280
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Tidskriftsartikel (refereegranskat)abstract
- Gut enzymes in the small intestine are exposed to extremely low electrical currents (ELEC) generated by the smooth muscle. In the present study, the in vitro tests were undertaken to evaluate the effect of these electric currents on the activity of the proteolytic pancreatic digestive enzymes. A simulator generating the typical electrical activity of pig gut was used for these studies. The electric current emitted by the simulator was transmitted to the samples, containing enzyme and its substrate, using platinum plate electrodes. All samples were incubated at 37 degrees C for I h. The changes in optical density, corresponding to enzyme activity, in samples stimulated for I h with ELEC was compared with that not exposed to ELEC. The obtained results show that the electrical current with the characteristics of the myoelectrical migrating complex (MMC) has an influence on pancreatic enzyme activity. Increased endopeptidase and reduced exopeptidase activity was noticed in samples treated with ELEC. This observation can be of important as analyzed factors which can alter enzymatic activity of the gut, can thus also affect feed/food digestibility. Bioelectromagnetics 28:275-280, 2007. (c) 2007 Wiley-Liss, Inc.
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| 8. |
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| 9. |
- Figueroa Karlström, Eduardo, et al.
(författare)
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Therapeutic staff exposure to magnetic field pulses during TMS/rTMS treatments
- 2006
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Ingår i: Bioelectromagnetics. - Hoboken : John Wiley & Sons. - 0197-8462 .- 1521-186X. ; 27:2, s. 156-158
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Tidskriftsartikel (refereegranskat)abstract
- Transcranial magnetic stimulation or repetitive transcranial magnetic stimulation (TMS/rTMS) is currently being used in treatments of the central nervous system diseases, for instance, depressive states. The principles of localized magnetic stimulation are summarized and the risk and level of occupational field exposure of the therapeutic staff is analyzed with reference to lCNIRP guidelines for pulses below 100 kHz. Measurements and analysis of the occupational exposure to magnetic fields of the staff working with TMS/rTMS are presented.
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| 10. |
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