| 1. |
- Andersson, N., et al.
(författare)
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Amplitude modulation of light from various sources
- 1994
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Ingår i: Lighting Research and Technology. - : Sage Publications. - 1477-1535 .- 1477-0938. ; 26:3, s. 157-160
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Tidskriftsartikel (refereegranskat)abstract
- This work was done to obtain basic knowledge about various light sources and specially about light modulation, or flicker. The study showed that the modulation of light varied a lot between different ordinary light sources. In general the 100 Hz component in the flickering light dominated. For incandescent lights the modulation increased with decreasing power and was in the range 10-22%. Light from the tungsten-halogen lamps had 2-6% modulation. The most common light sources (single-colour fluorescent light) had a modulation of about 20%. Fluorescent tubes with better colour rendering (full-colour fluorescent and full-colour special fluorescent tubes) had a higher modulation, 30-40%, while light from high-frequency (HF) fluorescent tubes had a modulation of 0.9%. Light from conventional compact fluorescent tubes had a modulation degree of about 44%, and for HF compact fluorescent tubes it was 2-7%. Modulation of light from HF compact fluorescent tubes had a tendency to decrease with increasing tube size. The modulation of light from discharge lamps was in the range of 52% up to 100% and the curve form of the light from low pressure sodium vapour lamp (100% modulation) contained several high frequency components.
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| 2. |
- Baste, Valborg, et al.
(författare)
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Pregnancy outcomes after paternal radiofrequency field exposure aboard fast patrol boats
- 2012
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Ingår i: Journal of Occupational and Environmental Medicine. - 1076-2752 .- 1536-5948. ; 54:4, s. 431-438
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To investigate adverse reproductive outcomes among male employees in the Royal Norwegian Navy exposed to radiofrequency electromagnetic fields aboard fast patrol boats. Methods: Cohort study of Royal Norwegian Navy servicemen linked to the Medical Birth Registry of Norway, including singleton offspring born between 1967 and 2008 (n = 37,920). Exposure during the last 3 months before conception (acute) and exposure more than 3 months before conception (nonacute) were analyzed. Results: Perinatal mortality and preeclampsia increased after service aboard fast patrol boats during an acute period and also after increased estimated radiofrequency exposure during an acute period, compared with service aboard other vessels. No associations were found between nonacute exposure and any of the reproductive outcomes. Conclusions: Paternal work aboard fast patrol boats during an acute period was associated with perinatal mortality and preeclampsia, but the cause is not clear.
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| 3. |
- Baste, Valborg, et al.
(författare)
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Prospective study of pregnancy outcomes after parental cell phone exposure : the Norwegian mother and child cohort study
- 2015
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Ingår i: Epidemiology. - 1044-3983. ; 26:4, s. 613-621
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Tidskriftsartikel (refereegranskat)abstract
- Background: Research about prenatal exposure to electromagnetic fields from cell phones among expectant parents and reproductive outcome is limited. The aim of this article is to investigate the association between pregnancy outcome and parental cell phone exposure in a large prospective study. Methods: The study was based on the Norwegian Mother and Child Cohort Study conducted during the decade 1999–2009. In that study, pregnant women were recruited before a routine ultrasound examination during gestational week 15; they answered a questionnaire at that time and again around gestational week 30. The expectant father was invited to answer a questionnaire during gestational week 15 (2001–2009). The forms contained questions regarding cell phone use. The response rate was 38.7% and the cohort comprised 100,730 singleton births. Pregnancy outcomes were obtained by linkage to the Medical Birth Registry of Norway. Results: The risk of preeclampsia was slightly lower among women with medium and high cell phone exposure compared with low exposure after adjusting for potential confounders. Fathers with testis exposure when using cell phones had a borderline increased risk of perinatal mortality among offspring and a slightly decreased risk of partner developing preeclampsia during pregnancy compared with no cell phone exposure of head or testis. None of the other pregnancy outcomes was associated with cell phone exposure. Conclusions: We found no association between maternal prenatal or paternal preconceptional cell phone exposure and any of the studied pregnancy outcomes. The only risk estimate suggesting a potential increased risk was not consistent with other findings.
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| 4. |
- 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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| 5. |
- Carlberg, Michael, et al.
(författare)
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Meningioma patients diagnosed 2007-2009 and the association with use of mobile and cordless phones : a case-control study
- 2013
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Ingår i: Environmental Health. - : BioMed Central (BMC). - 1476-069X. ; 12:60
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Tidskriftsartikel (refereegranskat)abstract
- Background: To study the association between use of wireless phones and meningioma. Methods: We performed a case-control study on brain tumour cases of both genders aged 18-75 years and diagnosed during 2007-2009. One population-based control matched on gender and age was used to each case. Here we report on meningioma cases including all available controls. Exposures were assessed by a questionnaire. Unconditional logistic regression analysis was performed. Results: In total 709 meningioma cases and 1,368 control subjects answered the questionnaire. Mobile phone use in total produced odds ratio (OR) = 1.0, 95% confidence interval (CI) = 0.7-1.4 and cordless phone use gave OR = 1.1, 95% CI = 0.8-1.5. The risk increased statistically significant per 100 h of cumulative use and highest OR was found in the fourth quartile (>2,376 hours) of cumulative use for all studied phone types. There was no statistically significant increased risk for ipsilateral mobile or cordless phone use, for meningioma in the temporal lobe or per year of latency. Tumour volume was not related to latency or cumulative use in hours of wireless phones. Conclusions: No conclusive evidence of an association between use of mobile and cordless phones and meningioma was found. An indication of increased risk was seen in the group with highest cumulative use but was not supported by statistically significant increasing risk with latency. Results for even longer latency periods of wireless phone use than in this study are desirable.
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| 6. |
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| 7. |
- 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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| 8. |
- Frankel, Jennifer, et al.
(författare)
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Assessing exposures to Magnetic resonance imaging's complex Mixture of Magnetic Fields for In Vivo, In Vitro, and epidemiologic studies of Health effects for staff and Patients
- 2018
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Ingår i: Frontiers In Public Health. - : Frontiers Media S.A.. - 2296-2565. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- A complex mixture of electromagnetic fields is used in magnetic resonance imaging (MRI): static, low-frequency, and radio frequency magnetic fields. Commonly, the static magnetic field ranges from one to three Tesla. The low-frequency field can reach several millitesla and with a time derivative of the order of some Tesla per second. The radiofrequency (RF) field has a magnitude in the microtesla range giving rise to specific absorption rate values of a few Watts per kilogram. Very little attention has been paid to the case where there is a combined exposure to several different fields at the same time. Some studies have shown genotoxic effects in cells after exposure to an MRI scan while others have not demonstrated any effects. A typical MRI exam includes muliple imaging sequences of varying length and intensity, to produce different types of images. Each sequence is designed with a particular purpose in mind, so one sequence can, for example, be optimized for clearly showing fat water contrast, while another is optimized for high-resolution detail. It is of the utmost importance that future experimental studies give a thorough description of the exposure they are using, and not just a statement such as "An ordinary MRI sequence was used." Even if the sequence is specified, it can differ substantially between manufacturers on, e.g., RF pulse height, width, and duty cycle. In the latest SCENIHR opinion, it is stated that there is very little information regarding the health effects of occupational exposure to MRI fields, and long-term prospective or retrospective cohort studies on workers are recommended as a high priority. They also state that MRI is increasingly used in pediatric diagnostic imaging, and a cohort study into the effects of MRI exposure on children is recommended as a high priority. For the exposure assessment in epidemiological studies, there is a clear difference between patients and staff and further work is needed on this. Studies that explore the possible differences between MRI scan sequences and compare them in terms of exposure level are warranted.
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| 9. |
- 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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| 10. |
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