| 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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| 11. |
- Frankel, Jennifer, et al.
(författare)
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EMF exposure variation among MRI sequences from pediatric examination protocols
- 2019
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Ingår i: Bioelectromagnetics. - : Wiley-Blackwell. - 0197-8462 .- 1521-186X. ; 40:1, s. 3-15
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Tidskriftsartikel (refereegranskat)abstract
- The magnetic resonance imaging (MRI) exposure environment is unique due to the mixture and intensity of magnetic fields involved. Current safety regulations are based on well-known acute effects of heating and neuroexcitation while the scientific grounds for possible long-term effects from MRI exposure are lacking. Epidemiological research requires careful exposure characterization, and as a first step toward improved exposure assessment we set out to characterize the MRI-patient exposure environment. Seven MRI sequences were run on a 3-Tesla scanner while the radiofrequency and gradient magnetic fields were measured inside the scanner bore. The sequences were compared in terms of 14 different exposure parameters. To study within-sequence variability, we varied sequence settings such as flip angle and slice thickness one at a time, to determine if they had any impact on exposure endpoints. There were significant differences between two or more sequences for all fourteen exposure parameters. Within-sequence differences were up to 60% of the corresponding between-sequence differences, and a 5-8 fold exposure increase was caused by variations in flip angle, slice spacing, and field of view. MRI exposure is therefore not only sequence-specific but also patient- and examination occurrence-specific, a complexity that requires careful consideration for an MRI exposure assessment in epidemiological studies to be meaningful.
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| 12. |
- Galt, Sheila, 1956, et al.
(författare)
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EXPERIMENTAL SEARCH FOR COMBINED AC AND DC MAGNETIC-FIELD EFFECTS ON ION CHANNELS
- 1993
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Ingår i: Bioelectromagnetics. - : Wiley. - 1521-186X .- 0197-8462. ; 14:4, s. 315-327
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Tidskriftsartikel (refereegranskat)abstract
- The hypothesis that specific combinations of DC and low frequency AC magnetic fields at so-called cyclotron-resonance conditions could affect the transport of ions through ion channels, or alter the kinetics of ion channels (opening and closing rates), has been tested. As a model system, the ion channels formed by gramicidin A incorporated in lipid bilayer membranes were studied. No significant changes in channel conductance, average lifetime, or formation rate as a function of applied fields could be detected over a wide range of frequencies and field strengths. Experiments were carried out to measure the time-resolved single-channel events and the average conductances of many-channel events in the presence of K+ and H+ ions. The channel blocking effect of Ca++ was also studied. (C) 1993 Wiley-Liss, Inc.
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| 13. |
- Gomez, Federico, et al.
(författare)
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Pulsed electric field reduces the permeability of potato cell wall
- 2008
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Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 29:4, s. 296-301
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Tidskriftsartikel (refereegranskat)abstract
- The effect of the application of pulsed electric fields to potato tissue on the diffusion of the fluorescent dye FMI-43 through the cell wall was studied. Potato tissue was subjected to field strengths ranging from 30 to 500 V/cm, with one 1 ms rectangular pulse, before application of FM1-43 and microscopic examination. Our results show a slower diffusion of FM1-43 in the electropulsed tissue when compared with that in the non-pulsed tissue, suggesting that the electric field decreased the cell wall permeability. This is a fast response that is already detected within 30 s after the delivery of the electric field. This response was mimicked by exogenous H2O2 and blocked by sodium azide, an inhibitor of the production of H2O2 by peroxidases.
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| 14. |
- Haarala, Christian, et al.
(författare)
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Electromagnetic field emitted by 902 MHz phones shows no effects on children's cognitive function
- 2005
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Ingår i: Bioelectromagnetics. - : Wiley-Liss. - 0197-8462 .- 1521-186X. ; 26:S7, s. S144-S150
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Tidskriftsartikel (refereegranskat)abstract
- The present study investigated the potential effects of a standard 902 MHz global system for mobile communication (GSM) mobile phone on 10–14 years old children’s cognitive function. A total of 32 children (16 boys, 16 girls) participated with their own and parental consent. The subjects were 10– 14 years old (mean 12.1 years, SD 1.1). They performed a battery of cognitive tests twice in a counterbalanced order: once while exposed to an active mobile phone and once during exposure to an inactive phone. The tests were selected from those we used earlier with adults. The statistical analyses showed no significant differences between the mobile phone off and on conditions in reaction times and accuracy over all tests or in any single test. It was concluded that a standard mobile phone has no effect on children’s cognitive function as measured by response speed and accuracy. The present results challenge some earlier findings suggesting that the electromagnetic field (EMF) created by an active mobile phone would facilitate cognitive functioning.
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| 15. |
- Hansson, Boel, et al.
(författare)
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Short-term effects experienced during examinations in an actively shielded 7T MR.
- 2019
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Ingår i: Bioelectromagnetics. - : Wiley. - 1521-186X .- 0197-8462. ; 40:4, s. 234-249
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to evaluate occurrence and strength of short-term effects experienced by study participants in an actively shielded (AS) 7 tesla (7T) magnetic resonance (MR) scanner, to compare results with earlier reports on passively shielded (PS) 7T MR scanners, and to outline possible healthcare strategies to improve patient compliance. Study participants (n=124) completed a web-based questionnaire directly after being examined in an AS 7T MR (n=154 examinations). Most frequently experienced short-term effects were dizziness (84%) and inconsistent movement (70%), especially while moving into or out of the magnet. Peripheral nerve stimulation (PNS)-twitching-was experienced in 67% of research examinations and showed a dependence between strength of twitches and recorded predicted PNS values. Of the participants, 74% experienced noise levels as acceptable and the majority experienced body and room temperature as comfortable. Of the study participants, 95% felt well-informed and felt they had had good contact with the staff before the examination. Willingness to undergo a future 7T examination was high (>90%). Our study concludes short-term effects are often experienced during examinations in an AS 7T MR, leaving room for improvement in nursing care strategies to increase patient compliance. Bioelectromagnetics. 2019;9999:XX-XX. © 2019 The Authors. Bioelectromagnetics Published by Wiley Periodicals, Inc.
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| 16. |
- Hansson Mild, Kjell, et al.
(författare)
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Exposure classification of MRI workers in epidemiological studies
- 2013
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Ingår i: Bioelectromagnetics. - Malden, MA : Wiley-Blackwell. - 0197-8462 .- 1521-186X. ; 34:1, s. 81-84
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Tidskriftsartikel (refereegranskat)abstract
- We estimate that there are about 100,000 workers from different disciplines, such as radiographers, nurses, anesthetists, technicians, engineers, etc., who can be exposed to substantial electromagnetic fields (compared to normal background levels) around magnetic resonance imaging (MRI) scanners. There is a need for well-designed epidemiological studies of MRI workers but since the exposure from MRI equipment is a very complex mixture of static magnetic fields, switched gradient magnetic fields, and radiofrequency electromagnetic fields (RF EMF), it is necessary to discuss how to assess the exposure in epidemiological studies. As an alternative to the use of job title as a proxy of exposure, we propose an exposure categorization for the different professions working with MRI equipment. Specifically, we propose defining exposure in three categories, depending on whether people are exposed to only the static field, to the static plus switched gradient fields or to the static plus switched gradient plus RF fields, as a basis for exposure assessment in epidemiological studies.
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| 17. |
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| 18. |
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| 19. |
- Hillert, Lena, et al.
(författare)
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The effects of 884 MHz GSM wireless communication signals on headache and other symptoms : an experimental provocation study.
- 2008
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Ingår i: Bioelectromagnetics. - : Wiley. - 1521-186X .- 0197-8462. ; 29:3, s. 185-96:Nov 28 [Epub ahead of print]
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Tidskriftsartikel (refereegranskat)abstract
- The effects of 884 MHz GSM wireless communication signals on headache and other symptoms: an experimental provocation study.Hillert L, Akerstedt T, Lowden A, Wiholm C, Kuster N, Ebert S, Boutry C, Moffat SD, Berg M, Arnetz BB.Department of Public Health Sciences, Division of Occupational Medicine, Karolinska Institutet, Stockholm, Sweden. lena.hillert@ki.seFindings from prior studies of possible health and physiological effects from mobile phone use have been inconsistent. Exposure periods in provocation studies have been rather short and personal characteristics of the participants poorly defined. We studied the effect of radiofrequency field (RF) on self-reported symptoms and detection of fields after a prolonged exposure time and with a well defined study group including subjects reporting symptoms attributed to mobile phone use. The design was a double blind, cross-over provocation study testing a 3-h long GSM handset exposure versus sham. The study group was 71 subjects age 18-45, including 38 subjects reporting headache or vertigo in relation to mobile phone use (symptom group) and 33 non-symptomatic subjects. Symptoms were scored on a 7-point Likert scale before, after 1(1/2) and 2(3/4) h of exposure. Subjects reported their belief of actual exposure status. The results showed that headache was more commonly reported after RF exposure than sham, mainly due to an increase in the non-symptom group. Neither group could detect RF exposure better than by chance. A belief that the RF exposure had been active was associated with skin symptoms. The higher prevalence of headache in the non-symptom group towards the end of RF exposure justifies further investigation of possible physiological correlates. The current study indicates a need to better characterize study participants in mobile phone exposure studies and differences between symptom and non-symptom groups. (c) 2007 Wiley-Liss, Inc.
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| 20. |
- Johansson, Amanda, et al.
(författare)
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No effect of mobile phone-like RF exposure on patients with atopic dermatitis
- 2008
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Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 29:5, s. 353-362
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the effect of exposure to a mobile phone-like radiofrequency (RF) electromagnetic field on people with atopic dermatitis (AD). Fifteen subjects with AD were recruited and matched with 15 controls without AD. The subjects were exposed for 30 min to an RF field at 1 W/kg via an indoor base station antenna attached to a 900 MHz GSM mobile phone. Blood samples for ELISA analysis of the concentration of substance P (SP), tumor necrosis factor receptor 1 (TNF RI), and brain derived neurotrophic factor (BDNF) in serum were drawn before and after the provocation (exposure/sham). Baseline heart rate and heart rate variability, local blood flow, and electrodermal activity were also recorded. No significant differences between the subject groups were found for baseline neurophysiological data. The cases displayed a serum concentration of TNF RI significantly higher than the control subjects and a significantly lower serum concentration of BDNF in the baseline condition. For SP there was no difference between groups. However, no effects related to RF exposure condition were encountered for any of the measured substances. As to symptoms, a possible correlation with exposure could not be evaluated, due to too few symptom reports. The result of the study does not support the hypothesis of an effect of mobile phone-like RF exposure on serum levels of SP, TNF RI, and BDNF in persons with AD.
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| 21. |
- Lowden, Arne, et al.
(författare)
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Sleep after mobile phone exposure in subjects with mobile phone-related symptoms
- 2011
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Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 32:1, s. 4-14
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Tidskriftsartikel (refereegranskat)abstract
- Several studies show increases in activity for certain frequency bands (10-14 Hz) and visually scored parameters during sleep after exposure to radiofrequency electromagnetic fields. A shortened REM latency has also been reported. We investigated the effects of a double-blind radiofrequency exposure (884 MHz, GSM signaling standard including non-DTX and DTX mode, time-averaged 10 g psSAR of 1.4 W/kg) on self-evaluated sleepiness and objective EEG measures during sleep. Forty-eight subjects (mean age 28 years) underwent 3 h of controlled exposure (7:30-10:30 PM; active or sham) prior to sleep, followed by a full-night polysomnographic recording in a sleep laboratory. The results demonstrated that following exposure, time in Stages 3 and 4 sleep (SWS, slow-wave sleep) decreased by 9.5 min (12%) out of a total of 78.6 min, and time in Stage 2 sleep increased by 8.3 min (4%) out of a total of 196.3 min compared to sham. The latency to Stage 3 sleep was also prolonged by 4.8 min after exposure. Power density analysis indicated an enhanced activation in the frequency ranges 0.5-1.5 and 5.75-10.5 Hz during the first 30 min of Stage 2 sleep, with 7.5-11.75 Hz being elevated within the first hour of Stage 2 sleep, and bands 4.75-8.25 Hz elevated during the second hour of Stage 2 sleep. No pronounced power changes were observed in SWS or for the third hour of scored Stage 2 sleep. No differences were found between controls and subjects with prior complaints of mobile phone-related symptoms. The results confirm previous findings that RF exposure increased the EEG alpha range in the sleep EEG, and indicated moderate impairment of SWS. Furthermore, reported differences in sensitivity to mobile phone use were not reflected in sleep parameters.
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| 22. |
- Lyskov, Eugene, et al.
(författare)
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Low frequency therapeutic EMF differently influences experimental muscle pain in female and male subjects.
- 2005
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Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 26:4, s. 299-304
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Tidskriftsartikel (refereegranskat)abstract
- Effects of a pulsating, half sine wave magnetic field (MF) with a frequency of 100 pps and 15 mT rms flux density, generated by the MD TEMF device (EMF Therapeutics, Inc., Chattanooga), on subjective pain rating, heart rate, and arterial blood pressure were tested in a double blind, crossover design study employing experimental muscle pain. Each of 24 healthy volunteers (12 females and 12 males, 24.7 +/- 3.2 years of age) received painful stimulation induced by the infusion of 5% hypertonic saline (HS) into the erector spinae muscle during real and sham MF exposure, in counterbalanced order. Exposure to MF differently affects subjective pain estimates in females and males. MF exposure increased averaged pain level and time integral of pain ratings in females, whereas no statistically significant difference for these characteristics was found in males. Pain related elevation of systolic and diastolic blood pressure was observed during both real and sham EMF exposure in female and male subjects.
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| 23. |
- Nadeem, Mohammad, 1964, et al.
(författare)
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Magnetic Field From Spot Welding Equipment - Is the Basic Restriction Exceeded?
- 2004
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Ingår i: Bioelectromagnetics. - : Wiley. - 1521-186X .- 0197-8462. ; 25:4, s. 278-284
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Tidskriftsartikel (refereegranskat)abstract
- A point measurement of the magnetic field (MF) near a typical spot welding machine showed that the magnetic flux density was above the ICNIRP reference level. To investigate if the basic restrictions were exceeded, the induced body currents in a full 3D human model were calculated. It was found that at an operator position of 34 cm away from the machine the maximum induced current density was below the ICNIRP basic restriction. But if the operator was closer to the machine, the basic restriction was exceeded. An important finding of the present article is that the basic restriction can be exceeded although the MF spatially averaged over the whole body is well below the reference level.
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| 24. |
- Neubauer, G, et al.
(författare)
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Feasibility of Future Epidemiological Studies on Possible Health Effects of Mobile Phone Base Stations
- 2007
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Ingår i: Bioelectromagnetics. - : Wiley. - 1521-186X .- 0197-8462. ; 28:3, s. 224 - 230
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Tidskriftsartikel (refereegranskat)abstract
- The increasing deployment of mobile communication base stations led to an increasing demand for epidemiological studies on possible health effects of radio frequency emissions. The methodological challenges of such studies have been critically evaluated by a panel of scientists in the fields of radiofrequency engineering/dosimetry and epidemiology. Strengths and weaknesses of previous studies have been identified. Dosimetric concepts and crucial aspects in exposure assessment were evaluated in terms of epidemiological studies on different types of outcomes. We conclude that in principle base station epidemiological studies are feasible. However, the exposure contributions from all relevant radio frequency sources have to be taken into account. The applied exposure assessment method should be piloted and validated. Short to medium term effects on physiology or health related quality of life are best investigated by cohort studies. For long term effects, groups with a potential for high exposure need to first be identified; for immediate effect, human laboratory studies are the preferred approach. © 2006 Wiley-Liss, Inc.
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| 25. |
- Nittby, Henrietta, et al.
(författare)
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Cognitive impairment in rats after long-term exposure to GSM-900 mobile phone radiation
- 2008
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Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 29:3, s. 219-232
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Tidskriftsartikel (refereegranskat)abstract
- Considering the frequent use of mobile phones, we have directed attention to possible implications on cognitive functions. In this study we investigated in a rat model the long-term effects of protracted exposure to Global System for Mobile Communication-900 MHz (GSM-900) radiation. Out of a total of 56 rats, 32 were exposed for 2 h each week for 55 weeks to radio-frequency electromagnetic radiation at different SAR levels (0.6 and 60 mW/kg at the initiation of the experimental period) emitted by a (GSM-900) test phone. Sixteen animals were sham exposed and eight animals were cage controls, which never left the animal house. After this protracted exposure, GSM-900 exposed rats were compared to sham exposed controls. Effects on exploratory behaviour were evaluated in the open-field test, in which no difference was seen. Effects on cognitive functions were evaluated in the episodic-like memory test. In our study, GSM exposed rats had impaired memory for objects and their temporal order of presentation, compared to sham exposed controls (P = 0.02). Detecting the place in which an object was presented was not affected by GSM exposure. Our results suggest significantly reduced memory functions in rats after GSM microwave exposure (P = 0.02).
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| 26. |
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| 27. |
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| 28. |
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| 29. |
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| 30. |
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| 31. |
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| 32. |
- Sarimov, Ruslan, et al.
(författare)
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Fifty Hertz Magnetic Fields Individually Affect Chromatin Conformation in Human Lymphocytes : Dependence on Amplitude, Temperature, and Initial Chromatin State
- 2011
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Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 32:7, s. 570-579
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Tidskriftsartikel (refereegranskat)abstract
- Effects of magnetic field (MF) at 50 Hz on chromatin conformation were studied by the method of anomalous viscosity time dependence (AVTD) in human lymphocytes from two healthy donors. MF within the peak amplitude range of 5-20 mu T affected chromatin conformation. These MF effects differed significantly between studied donors, and depended on magnetic flux density and initial condensation of chromatin. While the initial state of chromatin was rather stable in one donor during one calendar year of measurements, the initial condensation varied significantly in cells from another donor. Both this variation and the MF effect depended on temperature during exposure. Despite these variations, the general rule was that MF condensed the relaxed chromatin and relaxed the condensed chromatin. Thus, in this study we show that individual effects of 50 Hz MF exposure at peak amplitudes within the range of 5-20 mu T may be observed in human lymphocytes in dependence on the initial state of chromatin and temperature. Bioelectromagnetics 32:570-579, 2011.
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| 33. |
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| 34. |
- Schüz, J, et al.
(författare)
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Extremely low-frequency magnetic fields and risk of childhood leukemia: A risk assessment by the ARIMMORA consortium
- 2016
-
Ingår i: Bioelectromagnetics. - : Wiley. - 1521-186X .- 0197-8462. ; 37:3, s. 183-189
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Exposure to extremely low-frequency magnetic fields (ELF-MF) was evaluated in an International Agency for Research on Cancer (IARC) Monographs as possibly carcinogenic to humans in 2001, based on increased childhood leukemia risk observed in epidemiological studies. We conducted a hazard assessment using available scientific evidence published before March 2015, with inclusion of new research findings from the Advanced Research on Interaction Mechanisms of electroMagnetic exposures with Organisms for Risk Assessment (ARIMMORA) project. The IARC Monograph evaluation scheme was applied to hazard identification. In ARIMMORA for the first time, a transgenic mouse model was used to mimic the most common childhood leukemia: new pathogenic mechanisms were indicated, but more data are needed to draw definitive conclusions. Although experiments in different animal strains showed exposure-related decreases of CD8+ T-cells, a role in carcinogenesis must be further established. No direct damage of DNA by exposure was observed. Overall in the literature, there is limited evidence of carcinogenicity in humans and inadequate evidence of carcinogenicity in experimental animals, with only weak supporting evidence from mechanistic studies. New exposure data from ARIMMORA confirmed that if the association is nevertheless causal, up to 2% of childhood leukemias in Europe, as previously estimated, may be attributable to ELF-MF. In summary, ARIMMORA concludes that the relationship between ELF-MF and childhood leukemia remains consistent with possible carcinogenicity in humans. While this scientific uncertainty is dissatisfactory for science and public health, new mechanistic insight from ARIMMORA experiments points to future research that could provide a step-change in future assessments. Bioelectromagnetics. 37:183-189, 2016.
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| 35. |
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| 36. |
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| 37. |
- Sundström, Henrik, et al.
(författare)
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Measurements of the Ripple Effect and Geometric Distribution of Switched Gradient Fields Inside a Magnetic Resonance Scanner
- 2015
-
Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 36:2, s. 162-168
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Tidskriftsartikel (refereegranskat)abstract
- Knowledge of patient exposure during magnetic resonance imaging (MRI) procedures is limited, and the need for such knowledge has been demonstrated in recent in vitro and in vivo studies of the genotoxic effects of MRI. This study focuses on the dB/dt of the switched gradient field (SGF) and its geometric distribution. These values were characterized by measuring the peak dB/dt generated by a programmed gradient current of alternating triangles inside a 1.5T MR scanner. The maximum dB/dt exposure to the gradient field was 6-14T/s, and this occurred at the edges of the field of view (FOV) 20-25cm from the isocenter in the longitudinal direction. The dB/dt exposure dropped off to roughly half the maximum (3-7T/s) at the edge of the bore. It was found that the dB/dt of the SGF was distorted by a 200kHz ripple arising from the amplifier. The ripple is small in terms of B-field, but the high frequency content contributes to a peak dB/dt up to 18 times larger than that predicted by the slew rate (4T/sm) and the distance from the isocenter. Measurements on a 3T MRI scanner, however, revealed a much smaller filtered ripple of 100kHz in dB/dt. These findings suggest that the gradient current to each coil together with information on the geometrical distribution of the gradient field and ripple effects could be used to assess the SGF exposure within an MRI bore.
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| 38. |
- Testorf, Martin, et al.
(författare)
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Melanophore aggregation in strong static magnetic fields
- 2002
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Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 23:6, s. 444-449
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Tidskriftsartikel (refereegranskat)abstract
- Contradicting results can be found in the literature on effects from magnetic exposure to pigment cells. We have studied the influence of strong, static, homogenous magnetic fields of 8 and 14 T on melanophore aggregation during exposure to the field. Melanophores, black pigment cells, in fish are large flat cells having intracellular black pigment granules. Due to large size, high optical contrast, and quick response to drugs, melanophores are attractive as biosensors as well as for model studies of intracellular processes. This is especially true for modeling nerve cells, since melanophores share stem cells with axons. Twenty experiments on black tetra fish fins were carried out in the two magnetic flux densities. The same number of control experiments were carried out in the magnet with the magnetic field turned off. Several factors, such as the degree of maximal aggregation, speed of aggregation, and irregularity of the speed, were examined. The statistical analysis showed no significant field effects on the aggregation, with one exception: the irregularity in aggregation speed in the 8 T field, compared to control. The believed reorientation of the cytoskeleton (microtubules) in the field or the induced Lorentz force on moving pigment granules, did not affect the aggregation.
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| 39. |
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| 40. |
- Wiholm, Clairy, et al.
(författare)
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Mobile phone exposure and spatial memory.
- 2009
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Ingår i: Bioelectromagnetics. - : Wiley. - 1521-186X .- 0197-8462. ; 30:1, s. 59-65
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Tidskriftsartikel (refereegranskat)abstract
- Radiofrequency (RF) emission during mobile phone use has been suggested to impair cognitive functions, that is, working memory. This study investigated the effects of a 2 1/2 h RF exposure (884 MHz) on spatial memory and learning, using a double-blind repeated measures design. The exposure was designed to mimic that experienced during a real-life mobile phone conversation. The design maximized the exposure to the left hemisphere. The average exposure was peak spatial specific absorption rate (psSAR10g) of 1.4 W/kg. The primary outcome measure was a "virtual" spatial navigation task modeled after the commonly used and validated Morris Water Maze. The distance traveled on each trial and the amount of improvement across trials (i.e., learning) were used as dependent variables. The participants were daily mobile phone users, with and without symptoms attributed to regular mobile phone use. Results revealed a main effect of RF exposure and a significant RF exposure by group effect on distance traveled during the trials. The symptomatic group improved their performance during RF exposure while there was no such effect in the non-symptomatic group. Until this new finding is further investigated, we can only speculate about the cause.
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| 41. |
- Wilén, Jonna, et al.
(författare)
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Changes in heart rate variability among RF plastic sealer operators.
- 2007
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Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 28:1, s. 76-79
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Tidskriftsartikel (refereegranskat)abstract
- In a previous study, we showed that operators of radiofrequency (RF) plastic sealers, RF operators (n = 35) had a lower heart rate during nighttime compared to a control group (n = 37). We have analyzed the heart rate variability (HRV) on the same group of people to better understand the possible underlying rhythm disturbances. We found a significantly increased total HRV and very low frequency (VLF) power during nighttime among the RF operators compared to a control group. Together with our previous finding of a significantly lower heart rate during nighttime among the RF operators compared to the controls, this finding indicates a relative increase in parasympathetic cardiac modulation in RF operators. This could in turn be due to an adaptation of the thermoregulatory system and the cardiac autonomic modulation to a long-term low-level thermal exposure in the RF operators.
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| 42. |
- Wilén, Jonna, et al.
(författare)
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Electromagnetic field exposure and health among RF plastic sealer operators
- 2004
-
Ingår i: Bioelectromagnetics. - New York : Alan R. Liss, Inc.. - 0197-8462 .- 1521-186X. ; 25:1, s. 5-15
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Tidskriftsartikel (refereegranskat)abstract
- Operators of RF plastic sealers (RF operators) are an occupational category highly exposed to radiofrequency electromagnetic fields. The aim of the present study was to make an appropriate exposure assessment of RF welding and examine the health status of the operators. In total, 35 RF operators and 37 controls were included. The leakage fields (electric and magnetic field strength) were measured, as well as induced and contact current. Information about welding time and productivity was used to calculate time integrated exposure. A neurophysiological examination and 24 h ECG were also carried out. The participants also had to answer a questionnaire about subjective symptoms. The measurements showed that RF operators were exposed to rather intense electric and magnetic fields. The mean values of the calculated 6 min, spatially averaged E and H field strengths, in line with ICNIRP reference levels, are 107 V/m and 0.24 A/m, respectively. The maximum measured field strengths were 2 kV/m and 1.5 A/m, respectively. The induced current in ankles and wrists varied, depending on the work situation, with a mean value of 101 mA and a maximum measured value of 1 A. In total, 11 out of 46 measured RF plastic sealers exceeded the ICNIRP reference levels. RF operators, especially the ready made clothing workers had a slightly disturbed two-point discrimination ability compared to a control group. A nonsignificant difference between RF operators and controls was found in the prevalence of subjective symptoms, but the time integrated exposure parameters seem to be of importance to the prevalence of some subjective symptoms: fatigue, headaches, and warmth sensations in the hands. Further, RF operators had a significantly lower heart rate (24 h registration) and more episodes of bradycardia compared to controls.
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| 43. |
- Wilén, Jonna
(författare)
-
Exposure assessment of electromagnetic fields near electrosurgical units.
- 2010
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Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 31:7, s. 513-518
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Tidskriftsartikel (refereegranskat)abstract
- Electrosurgical units (ESU) are widely used in medical health services. By applying sinusoidal or pulsed voltage in the frequency range of 0.3-5 MHz to the electrode tip, the desired mixture of coagulation and cutting are achieved. Due to the high voltage and current in the cable, strong electromagnetic fields appear near the ESU. The surgeon and others inside the operating room such as nurses, anesthesiologists, etc., will be highly exposed to these fields. The stray fields surrounding the ESU have previously been measured, but now a deeper analysis has been made of the curve shape of the field and the implication of this when assessing exposure from a commonly used ESU in accordance with the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. The result showed that for some of the modes, especially those using high-pulsed voltage with only a few sinusoidal periods, the E-field close to the cable could reach linear spatially averaged values of 20 kV/m compared to the 2.1 kV/m stated in ICNIRP guidelines. Assessing the E- and B-field from ESU is not straightforward since in this frequency range, both induced current density and specific absorption rate are restricted by the ICNIRP guidelines. Nevertheless, work needs to be done to reduce the stray fields from ESU. Bioelectromagnetics (c) 2010 Wiley-Liss, Inc.
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| 44. |
- Wilén, Jonna, et al.
(författare)
-
Modification of pulse sequences reduces occupational exposure from MRI switched gradient fields : Preliminary results.
- 2010
-
Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 31:1, s. 85-87
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Tidskriftsartikel (refereegranskat)abstract
- The gradient fields in magnetic resonance imaging (MRI) will in some circumstances exceed the ICNIRP guidelines of occupational electromagnetic field exposure when personnel are near the scanner during MRI scanning. In this work we have shown that using commercially available modified sequences for noise reduction purposes, exposure will decrease by a factor of 1.5 with preserved image quality. This is a first step toward optimizing occupational exposure within the scanner room without affecting image quality. Bioelectromagnetics 31:85-87, 2010. (c) 2009 Wiley-Liss, Inc.
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| 45. |
- Wilén, Jonna, et al.
(författare)
-
Psychophysiological tests and provocation of subjects with mobile phone related symptoms
- 2006
-
Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 27:3, s. 204-214
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to investigate the effect of exposure to a mobile phone-like radiofrequency (RF) electromagnetic field on persons experiencing subjective symptoms when using mobile phones (MP). Twenty subjects with MP-related symptoms were recruited and matched with 20 controls without MP-related symptoms. Each subject participated in two experimental sessions, one with true exposure and one with sham exposure, in random order. In the true exposure condition, the test subjects were exposed for 30 min to an RF field generating a maximum SAR(1g) in the head of 1 W/kg through an indoor base station antenna attached to a 900 MHz GSM MP. The following physiological and cognitive parameters were measured during the experiment: heart rate and heart rate variability (HRV), respiration, local blood flow, electrodermal activity, critical flicker fusion threshold (CFFT), short-term memory, and reaction time. No significant differences related to RF exposure conditions were detected. Also no differences in baseline data were found between subject groups, except for the reaction time, which was significantly longer among the cases than among the controls the first time the test was performed. This difference disappeared when the test was repeated. However, the cases differed significantly from the controls with respect to HRV as measured in the frequency domain. The cases displayed a shift in low/high frequency ratio towards a sympathetic dominance in the autonomous nervous system during the CFFT and memory tests, regardless of exposure condition. This might be interpreted as a sign of differences in the autonomous nervous system regulation between persons with MP related subjective symptoms and persons with no such symptoms.
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| 46. |
- Wilén, Jonna, et al.
(författare)
-
Subjective symptoms among mobile phone users : a consequence of absorption of radiofrequency fields?
- 2003
-
Ingår i: Bioelectromagnetics. - New York : Wiley. - 0197-8462 .- 1521-186X. ; 24:3, s. 152-159
-
Tidskriftsartikel (refereegranskat)abstract
- In a previous epidemiological study, where we studied the prevalence of subjective symptoms among mobile phone (MP) users, we found as an interesting side finding that the prevalence of many of the subjective symptoms increased with increasing calling time and number of calls per day. In this extrapolative study, we have selected 2402 people from the epidemiological study who used any of the four most common GSM MP. We used the information about the prevalence of symptoms, calling time per day, and number of calls per day and combined it with measurements of the Specific Absorption Rate (SAR). We defined three volumes in the head and measured the maximum SAR averaged over a cube of 1 g tissue (SAR(1g)) in each volume. Two new exposure parameters Specific Absorption per Day (SAD) and Specific Absorption per Call (SAC) have been devised and are obtained as combinations of SAR, calling time per day, and number of calls per day, respectively. The results indicates that SAR values >0.5 W/kg may be an important factor for the prevalence of some of the symptoms, especially in combination with long calling times per day.
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| 47. |
- Wilén, Jonna, et al.
(författare)
-
Valid Exposure Protocols Needed in Magnetic Resonance Imaging Genotoxic Research
- 2020
-
Ingår i: Bioelectromagnetics. - : WILEY. - 0197-8462 .- 1521-186X. ; 41:3, s. 247-257
-
Tidskriftsartikel (refereegranskat)abstract
- Several in vitro and in vivo studies have investigated if a magnetic resonance imaging (MRI) examination can cause DNA damage in human blood cells. However, the electromagnetic field (EMF) exposure that the cells received in the MR scanner was not sufficiently described. The first studies looking into this could be regarded as hypothesis-generating studies. However, for further exploration into the role of MRI exposure on DNA integrity, the exposure itself cannot be ignored. The lack of sufficient method descriptions makes the early experiments difficult, if not impossible, to repeat. The golden rule in all experimental work is that a study should be repeatable by someone with the right knowledge and equipment, and this is simply not the case with many of the recent studies on MRI and genotoxicity. Here we discuss what is lacking in previous studies, and how we think the next generation of in vitro and in vivo studies on MRI and genotoxicity should be performed. Bioelectromagnetics.
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| 48. |
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| 49. |
- Baureus Koch, Catrin, et al.
(författare)
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Interaction between weak low frequency magnetic fields and cell membranes.
- 2003
-
Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462. ; 24:6, s. 395-402
-
Tidskriftsartikel (refereegranskat)abstract
- The question of whether very weak low frequency magnetic fields can affect biological systems, has attracted attention by many research groups for quite some time. Still, today, the theoretical possibility of such an interaction is often questioned and the site of interaction in the cell is unknown. In the present study, the influence of extremely low frequency (ELF) magnetic fields on the transport of Ca2+ was studied in a biological system consisting of highly purified plasma membrane vesicles. We tested two quantum mechanical theoretical models that assume that biologically active ions can be bound to a channel protein and influence the opening state of the channel. Vesicles were exposed for 30 min at 32 °C and the calcium efflux was studied using radioactive 45Ca as a tracer. Static magnetic fields ranging from 27 to 37 T and time varying magnetic fields with frequencies between 7 and 72 Hz and amplitudes between 13 and 114 T (peak) were used. We show that suitable combinations of static and time varying magnetic fields directly interact with the Ca2+ channel protein in the cell membrane, and we could quantitatively confirm the model proposed by Blanchard. Bioelectromagnetics 24:395-402, 2003. © 2003 Wiley-Liss, Inc.
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