Uniphasic and diphasic wave forms of the skin potential response.
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Galvanic Skin Response↗
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Results for “Radiation, Nonionizing”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
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Terahertz imaging: T-ray specs.
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Bacillus anthracis↗
The hydrologic cycle in deep-time climate problems.
Hydrology refers to the whole panoply of effects the water molecule has on climate and on the land surface during its journey there and back again between ocean and atmosphere. On its way, it is cycled through vapour, cloud water, snow, sea ice and glacier ice, as well as acting as a catalyst for silicate-carbonate weathering reactions governing atmospheric carbon dioxide. Because carbon dioxide affects the hydrologic cycle through temperature, climate is a pas des deux between carbon dioxide and water, with important guest appearances by surface ice cover.
Climate↗
Effects of electromagnetic radiation from a cellular telephone on epidermal Merkel cells.
The number of reports on the effects induced by electromagnetic radiation (EMR) from cellular telephones in various cellular systems is still increasing. Until now, no satisfactory mechanism has been proposed to explain the biological effects of this radiation except a role suggested for mast cells. Merkel cells may also play a role in the mechanisms of biological effects of EMR. This study was undertaken to investigate the influence of EMR from a cellular telephone (900 MHz) on Merkel cells in rats. A group of rats was exposed to a cellular telephone in speech position for 30 min. Another group of rats was sham-exposed under the same environmental conditions for 30 min. Exposure led to significantly higher exocytotic activity in Merkel cells compared with the sham exposure group. This finding may indicate the possible role of Merkel cells in the pathophysiology of the effects of EMR.
Animals↗
The seismic wave casualties in Hilo, Hawaii.
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Disasters↗
Delivery outcome among physiotherapists in Sweden: is non-ionizing radiation a fetal hazard?
A cohort study was made on 2,043 infants born to 2,018 females registered as physiotherapists at the time of pregnancy during 1973 to 1978. The incidence of perinatal death, serious malformation, short gestational duration, and low birth weight was slightly below the expected with consideration given to maternal age and parity distribution. Information on occupational exposure (use of shortwave, microwave, and ultrasonic equipment, X-ray exposure, use of electrostimulator or hexachlorophene-containing soaps) was obtained in a case-control study within the cohort from mail questionnaires with a 93% response rate. The only positive finding was a higher incidence of shortwave equipment use among the females with a dead or malformed infant than among controls. Various explanations for this finding are discussed.
Abnormalities, Radiation-Induced↗
Mobile telephones and brain vascular leakage.
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Albumins↗
Scaling the physiological effects of exposure to radiofrequency electromagnetic radiation: consequences of body size.
We have demonstrated that a comparative analysis of the physiological effects of exposure of laboratory mammals to radiofrequency electromagnetic radiation (RFR) may be useful in predicting exposure thresholds for humans if the effect is assumed to be due only to heating of tissue. The threshold specific absorption rate (SAR) necessary to affect a thermoregulatory parameter shows an inverse and linear relationship to body mass. The inverse relationship between threshold SAR and body mass is attributed to a surface area: body mass relationship. In comparison to small mammals, relatively large mammals have a reduced capacity to dissipate an internal heat load passively, and are therefore physiologically more sensitive to RFR exposure. The threshold for a thermoregulatory response depends on the type of response measured, species, ambient temperature, etc. By extrapolation, it can be shown that a SAR of only 0.2-0.4 W/kg is required to promote a thermoregulatory response in a mammal with a body mass of 70 kg (e.g. weight of adult human). The specific absorption rate bioeffects data collected from laboratory mammals can be related by means of a simple power formula: threshold SAR (W/kg) = aMb, where M is body mass in kg, a is a constant and b is equal to approximately -0.5. Through this equation we have illustrated that a threshold SAR measured in a species weighing 100 g would be 10 times greater than that of a species weighing 10 000 g. Accordingly, a relatively low SAR that is physiologically ineffective in small mammals may be stressful to larger species.
Animals↗
EU Directive, ICNIRP guidelines and Polish legislation on electromagnetic fields.
This review describes the general provisions of and the philosophy behind European Directive 2004/40/EC and ICNIRP (International Commission on Non-Ionizing Radiation Protection) guidelines. As an example of national legislation on the protection of workers against excessive electromagnetic field exposure, regulations established in Poland are summarized. The problems of a practical implementation of the Directive's provisions are discussed.
Electromagnetic Fields↗
Magnetic fields of induction heaters in the framework of directive 2004/40/EC of the European Parliament and of the Council.
The spectrum and the polarization of the magnetic flux density (B-field) of 6 induction heaters and 1 arc oven were measured by means of a PMM (Italy) spectrum analyser. The spectrum analysis showed that no substantial harmonics were observed while the polarization analysis revealed that the operator's exposure was non-homogeneous within a distance of 1.5 m from the heater. When the distance was larger, the body was homogeneously exposed. In general we can state that the B-field strongly varied between heaters and that exposure exceeded the occupational reference levels recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) (1998) and European Directive 2004/40/EC in 5 of the 7 heaters. Within the framework of the Directive some protection actions should be taken. Whereas mitigation of existing/old induction ovens is difficult, the design of new induction heaters and their housing should be based, among others, on electromagnetic reducing engineering concepts.
Electromagnetic Fields↗
Health risk assessment of occupational exposure to a magnetic field from magnetic resonance imaging devices.
Health care staff who operate magnetic resonance imaging (MRI) devices are exposed to a static magnetic field of significant spatial heterogenity always produced by MRI magnets during the whole shift. They can also be exposed to pulses of a time-varying magnetic field (gradient field) present only during patients' examinations. The level of the workers' exposure depends both on the type of the magnet and on the ergonomic design of each MRI device. The paper presents methods used for measuring and assessing workers' exposure. It also discusses the results of inspection measurements carried out next to approximately 20 MRI devices of approximately 0.2-2.0 T. The presented characteristic and overview of the variability of workers' exposure to a variety of MRI devices supports the need for data on monitoring occupational exposure to MRI. International exposure assessment standards and guidelines (International Commission on Non-Ionizing Radiation Protection [ICNIRP], Institute of Electrical and Electronics Engineers [IEEE], American Conference of Governmental and Industrial Hygienists [ACGIH], European Commission directive), and those established in Poland are also compared.
Electromagnetic Fields↗
Quasi-static electromagnetic dosimetry: from basic principles to examples of applications.
An overview of quasi-static electromagnetic dosimetry is presented. After an introductive description of quantities and standards and a quick look at experimental and analytical approaches, attention is focused on numerical dosimetry. The process that leads to the calculation of results is analyzed in its basic steps, including the representation of the human body by means of a realistic voxel phantom. The most popular numerical methods are then described. An analysis of different methods in the same framework emphasizes common features and differences. This can help in choosing a more suitable method to solve a particular problem. An example of an application is finally reported.
Dose-Response Relationship, Radiation↗
Occupational exposures to radiofrequency radiation (18-31 MHz) from F dielectric heat sealers.
The National Institute for Occupational Safety and Health (NIOSH) has initiated an epidemiologic study to evaluate whether or not radiofrequency (RF) radiation in the 10--100 MHz range has any effects on the reproductive functions of exposed workers. Initial investigations indicated that a suitable population for this study might exist in industries utilizing RF dielectric heat sealers. To estimate exposure levels of RF heat sealer operators, NIOSH made exposure measurements for 82 operators in 13 facilities with a Narda Broadband Isotropic Radiation Monitor, Model 25540 with an electric (E) field probe. Model 8644 and a magnetic (H) field probe, Model 8635. The geometric mean of the maximum measured exposures was at least 200 V/m for the E-field and 0.094 A/m for the H-field. The Occupational Safety and Health Administration (OSHA) exposure standard for RF radiation in the range of 10--100,000 MHz is 10 mW/cm2 as averaged over any 0.1-hour period. This value corresponds to an exposure of 200 V/m for the E-field and 0.5 A/m for the H-field. NIOSH found that 55% of the heat sealer operators were exposed to levels for the E-field above 200 V/m; for the H-field, 21% of the operators were exposed to levels above 0.5 A/m. For the heat sealers evaluated, the frequencies ranged from 18 to 31 MHz. On the basis of these environmental data, RF heat sealer operators experience a wide range of exposures both above and below the OSHA standard. The exposure range is sufficiently broad to make these operators adequate candidates for epidemiologic study.
Environmental Exposure↗
ELF non ionizing radiation changes the distribution of the inner chemical functional groups in human epithelial cell (HaCaT) culture.
Human skin cell culture (HaCaT) that has been exposed to an AC magnetic field undergoes detectable changes in its biochemical properties and shapes. Such changes were observed by infrared wavelength-selective scanning near-field optical microscopy with a resolution of 80-100 nm. We specifically investigated the changes in the distribution of the inner chemical functional groups and in the cell morphology induced by a 24 h exposure to a 1 mT (rms), 50 Hz sinusoidal magnetic field in a temperature regulated solenoid. These results further accentuate the crucial questions, raised by several recent studies, about the impact of low-frequency electromagnetic field on human cells.
Cell Adhesion↗
Exclusion zones close to wireless communication transmitters aiming to reduce human health risks.
The electromagnetic fields (EMFs) radiated from typical cellular phone transmitter stations are calculated and compared to available guidelines considering thermal and non thermal biological effects. Exclusion zones close to the transmitter station are then estimated. These are three-dimensional figures calculated in comparison to a chosen EMF reference human exposure guideline limit. The volume inside them represents the regions in which the estimated electromagnetic field level is above the limit. Outside the exclusion zone the estimated electromagnetic field is below the limits. This procedure can be very useful in many applications, e.g., when a transmitter station is expected to be placed close to schools, hospitals, or close to areas where people live or work and where they spend much time each day. Owing to the uncertainty in science regarding the minimum non ionizing radiation level below which no adverse health effects can occur, the Precautionary Approach is suggested and it is recommended that EMF human exposure be kept to a minimum.
Cell Phone↗
Electromagnetic dosimetry in a Crawford cell: 225 to 500 MHz.
A Crawford cell exposure chamber (main section 30 cm square) was used for electromagnetic dosimetry in the 225 to 500 MHz frequency range. Electric field patterns were measured within the cell. No higher-order modes were observed at any of the frequencies studied below 500 MHz, but significant field perturbations were seen at 2450 MHz. Energy absorption in a prolate spheroidal hamster phantom and in saline-filled spheres of various sizes was measured. The normalized whole-body specific absorption rate (SAR) in watts/kg per mW/cm2 increased from 0.11 (at 225 MHz) to 0.42 (at 450 MHz) for the hamster phantom in E polarization, from 0.06 (at 325 MHz) to 0.20 (at 500 MHz) for K polarization, and from 0.03 (at 325 MHz) to 0.12 (at 500 MHz) for H polarization. Although these values exceed predictions from the long-wavelength far-field approximation for power absorption, the measured SARs were corroborated directly using calorimetry. In addition, calorimetric data obtained using saline-filled spheres suggests that absorbed power in a Crawford cell converges to the far-field plane wave theoretical values only for objects occupying less than 20% of the vertical dimension from the septum to the outer wall.
Electromagnetic Fields↗
Analysis of the influence of the cell geometry, orientation and cell proximity effects on the electric field distribution from direct RF exposure.
This paper shows the importance of using a cell model with the proper geometry, orientation and internal structure to study possible cellular effects from direct radiofrequency exposure. For this purpose, the electric field intensity is calculated, using the finite element numerical technique, in single- and multilayer spherical, cylindrical and ellipsoidal mammalian cell models exposed to linearly polarized electromagnetic plane waves of frequencies 900 and 2450 MHz. An extensive analysis is performed on the influence that the cell geometry and orientation with respect to the external field have in the value of the electric field induced in the membrane and cytoplasm. We also show the significant role that the cytoplasmic and extracellular bound water layers play in determining the electric field intensity for the cylindrical and ellipsoidal cell models. Finally, a study of the mutual interactions between cells shows that polarizing effects between cells significantly modify the values of field intensity within the cell.
Cell Membrane↗
Response, thermal regulatory threshold and thermal breakdown threshold of restrained RF-exposed mice at 905 MHz.
The objective of this study was the determination of the thermal regulatory and the thermal breakdown thresholds for in-tube restrained B6C3F1 and NMRI mice exposed to radiofrequency electromagnetic fields at 905 MHz. Different levels of the whole-body averaged specific absorption rate (SAR = 0, 2, 5, 7.2, 10, 12.6 and 20 W kg(-1)) have been applied to the mice inside the 'Ferris Wheel' exposure setup at 22 +/- 2 degrees C and 30-70% humidity. The thermal responses were assessed by measurement of the rectal temperature prior, during and after the 2 h exposure session. For B6C3F1 mice, the thermal response was examined for three different weight groups (20 g, 24 g, 29 g), both genders and for pregnant mice. Additionally, NMRI mice with a weight of 36 g were investigated for an interstrain comparison. The thermal regulatory threshold of in-tube restrained mice was found at SAR levels between 2 W kg(-1) and 5 W kg(-1), whereas the breakdown of regulation was determined at 10.1 +/- 4.0 W kg(-1)(K = 2) for B6C3F1 mice and 7.7 +/- 1.6 W kg(-1)(K = 2) for NMRI mice. Based on a simplified power balance equation, the thresholds show a clear dependence upon the metabolic rate and weight. NMRI mice were more sensitive to thermal stress and respond at lower SAR values with regulation and breakdown. The presented data suggest that the thermal breakdown for in-tube restrained mice, whole-body exposed to radiofrequency fields, may occur at SAR levels of 6 W kg(-1)(K = 2) at laboratory conditions.
Animals↗