bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetite biomineralization and geomagnetic sensitivity in higher animals: An update and recommendations for future study
Authors: Kirschvink Joseph L.
Published: February 2006

Magnetite, the only known biogenic material with ferromagnetic properties, has been identified as a biochemical precipitate in three of the five kingdoms of living organisms, with a fossil record that now extends back nearly 2 billion years. In the magnetotactic bacteria, protoctists, and fish, single‐domain crystals of magnetite are arranged in membrane‐bound linear structures called magnetosomes, which function as biological bar magnets. Magnetosomes in all three of these groups bear an overall structural similarity to each other, which includes alignment of the individual crystallographic [111] directions parallel to the long axis. Although the magnetosomes represent only a small volume fraction in higher organisms, enough of these highly energetic structures are present to provide sensitivity to extremely small fluctuations and gradients in the background geomagnetic field. Previous experiments with elasmobranch fish are reexamined to test the hypothesis that gradients played a role in their successful geomagnetic conditioning, and a variety of four‐turn coil designs are considered that could be used to test the various hypotheses proposed for them.
Chronic exposure of primates to 60‐Hz electric and magnetic fields: III. Neurophysiologic effects
Authors: Dowman Robert , Wolpaw Jonathan R. , Seegal Richard F. , Satya‐Murti Saty
Published: February 2006

The neurophysiologic effects of combined 60‐Hz electric (E) and magnetic (B) fields, of magnitudes comparable to those produced by high‐voltage powerlines, were investigated in 10 monkeys (Macaca nemestrina). Six animals (experimental group) were each exposed to three different levels of E and B fields: 3 kV/m and 0.1 G, 10 kV/m and 0.3 G, and 30 kV/m and 0.9 G. Field exposures were preceded and followed by sham exposures, during which factors of field generation were present (e.g., heat, vibration, noise, etc.) without E and B fields. Each of the five segments (i.e., the three exposure segments and the initial and final sham exposure segments) lasted 3 weeks. Animals were exposed for 18 h/day (fields on at 1600 h, off at 1000 h). Four other animals (external control group) were given sham exposure for the entire 15‐week period. Auditory, visual, and somatosensory evoked potentials were recorded twice a week, during the daily 6‐h field‐off period.

E‐ and B‐field exposure had no effect on the early or mid‐latency evoked potential components, suggesting that exposure at these levels has no effect on peripheral or central sensory afferent pathways. However, there was a statistically significant decrease in the amplitudes of late components of the somatosensory evoked potential during the 10kV/m and 0.3 G, and 30 kV/m and 0.9 G exposure levels. This result is possibly related to the opiate antagonist effect of electromagnetic field exposure reported by others.
Detection‐threshold of 50‐Hz electric fields by human subjects
Authors: Kato M. , Ohta S. , Shimizu K. , Tsuchida Y. , Matsumoto G.
Published: February 2006

The threshold intensity for detection of an AC electric field was studied in human subjects at several different temperatures and humidities. The dorsum and palm of the hand were exposed to fields, representing hairy and hairless skin, in order to clarify whether hair movement is critical for field detection. Experiments were carried out on human subjects (seven men and four women) during hot humid weather of July–August and dry cool air of October–November. Threshold values obtained in the summer were 30–65 kV/m for the hairy skin on the dorsum of the hand, while for the hairless skin on the palm the threshold was > 115 kV/m (highest field available due to limitations of the power supply). During the fall, the threshold was much higher than during the summer. We sought possible reasons for the difference and found that humidity was the main factor. Relative permittivity of woman's hair was then estimated by measuring capacitance of the hairs under dry (35% RH) and wet (85% RH) conditions at 20 °C. The values of relative permittivity obtained under these two conditions differed by several times the average. The differences in detection thresholds may be attributable to the different relative permittivities of the hairs under dry and wet conditions.
Lack of effects from 2000‐Hz magnetic fields on mammary adenocarcinoma and reproductive hormones in rats
Authors: Baumann Stephen , Cooper Ralph , Berman Ezra , House Dennis , Joines William
Published: February 2006

Female rats were implanted with mammary adenocarcinoma tissue and 25 days later exposed to 2,000‐Hz magnetic fields 1 h a day for 9 days. Analysis showed that tumor weights and the levels of several reproductive hormones were not significantly different between treated and control animals. Other studies with a similar design have also reported no significant effects from magnetic field exposure. However, vaginal smear data from all animals revealed that handling and restraint stress may have confounded the detection of subtle magnetic field effects.
Rats reproduce and rear litters during chronic exposure to 150‐kV/m, 60‐Hz electric fields
Authors: Rommereim D. N. , Kaune W. T. , Anderson L. E. , Sikov M. R.
Published: February 2006

Mature female rats and their subsequent litters were exposed either to 112‐ or to 150‐kV/m, 60‐Hz electric fields or sham‐exposed for 19 h daily through pre‐breeding, breeding, and rearing periods of experimentation. Exposed females mated in equal percentages and reared litters of equal numbers, and mean body masses of pups were the same as those of sham‐exposed animals. Thus, experiments to investigate electric‐field effects on reproduction and development in rats are feasible at effective field strengths of 112 and 150 k V/m.
In vitro lymphocyte proliferation induced by radio‐frequency electromagnetic radiation under isothermal conditions
Authors: Cleary Stephen F. , Liu Li‐Ming , Merchant Randall E.
Published: February 2006

Whole human blood was exposed or sham‐exposed in vitro for 2 h to 27 or 2,450 MHz radio‐frequency electromagnetic (RF) radiation under isothermal conditions (i.e., 37 ± 0.2 °C). Immediately after exposure, mononuclear cells were separated from blood by Ficoll density‐gradient centrifugation and cultured for 3 days at 37°C with or without mitogenic stimulation by phytohemagglutinin (PHA). Lymphocyte proliferation was assayed at the end of the culture period by 6 h of pulse labeling with 3H‐thymidine 3H‐TdR). Exposure to radiation at either frequency at specific absorption rates (SARs) below 50 W/kg resulted in a dose‐dependent, statistically significant increase of 3H‐TdR uptake in PHA‐activated or unstimulated lymphocytes. Exposure at 50 W/kg or higher suppressed 3H‐TdR uptake relative to that of sham‐exposed cells. There were no detectable effects of RF radiation on lymphocyte morphology or viability. Notwithstanding the characteristic temperature dependence of lymphocyte activation in vitro, the isothermal exposure conditions of this study warrant the conclusion that the biphasic, dose‐dependent effects of the radiation on lymphocyte proliferation were not dependent on heating.
Magnetic resonance imaging: Calculation of rates of energy absorption by a human‐torso model
Authors: Grandolfo Martino , Vecchia Paolo , Gandhi Om P.
Published: February 2006

The three‐dimensional impedance method was used to estimate specific absorption rate (SAR) in a human‐torso model during exposure to the time‐varying and static magnetic fields used in magnetic resonance imaging (MRI). Analytical data for discrete tissues as well as the entire torso are presented. Generalized equations were derived that enable calculation of whole‐torso SAR over a broad range of conditions. In addition, the impedance method can generate data about internal distributions of SAR, which are needed to predict critical organs that might undergo excessive elevations of temperature. Fair to good agreement was found between impedance‐method SAR and those predicted by simple phenomenological models.
Proflavin and microwave radiation: Absence of a mutagenic interaction
Authors: Meltz Martin L. , Eagan Phyllis , Erwin David N.
Published: February 2006

The potential ability of radiofrequency electromagnetic radiation (RFR) in the microwave range to induce mutagenesis, chromosomal aberrations, and sister chromatid exchanges in mammalian cells is being explored in our laboratories. In addition, we have also been examining the ability of simultaneous exposure to RFR and chemical mutagens to alter the genotoxic damage induced by chemical mutagens acting alone. We have performed experiments to determine whether there is an interaction between 2.45‐GHz, pulsed‐wave, RFR and proflavin, a DNA‐intercalating drug. The endpoint studied was forward mutation at the thymidine kinase locus in L5178Y mouse leukemic cells. Any effect on the size distribution of the resulting colonies of mutated cells was also examined. The exposures were performed at net forward powers of 500 or 600 W, resulting in a specific absorption rate (SAR) of ∼40 W/kg. The culture‐medium temperature reached a 3°C maximal increase during the 4‐h exposure; appropriate 37°C and convection‐heating temperature controls (TC) were performed. In no case was there any indication of a statistically significant increase in the induced mutant frequency due to the simultaneous exposure to RFR and proflavin, as compared with the proflavin exposures alone. There was also no indication of any change in the colony‐size distribution of the resulting mutant colonies, neither, and there was no evidence in these experiments of any mutagenic action by the RFR exposure alone.
Importance of alignment between local DC magnetic field and an oscillating magnetic field in responses of brain tissue in vitro and in vivo
Authors: Blackman C. F. , Benane S. G. , House D. E. , Elliott D. J.
Published: February 2006

The frequency dependence of the electric and magnetic (EM)‐field‐induced release of calcium ions from an in vitro brain tissue preparation has been shown to be a function of the density of the local DC magnetic field (BdC). In this study, we demonstrate that the relative orientation of the Bdc and the magnetic component (Bac) of a 315‐Hz EM signal (15 Vrms/m and 61 nTrms) are crucial for the induced release to be observed. The induced release occurs only when the Bdc and the Bac are perpendicular, and not when they are parallel. This finding is consistent with a magnetic resonance‐like transduction mechanism for the conversion of EM energy into a physicochemical change, and contrasts with the requirement for parallel Bdc and Bac components in the diatom‐mobility experiments of Smith et al. A review of the exposure conditions in the rat behavioral experiments conducted by Thomas et al. identifies unhydrated calcium and zinc ions as alternatives to lithium ions as candidates for interaction under parallel magnetic‐field orientations but fails to reject perpendicular orientations as an alternative basis for the phenomenon. Investigators that attempt to confirm the rat behavioral experiments should be aware of the conflicting exposure conditions that can be assumed to be operative, and they should design their experiments to test all conditions accordingly.
Electric fields and surface charges induced by ELF magnetic fields
Authors: Polk Charles
Published: February 2006

A method is described for evaluating electric fields induced by ELF magnetic fields into electrically inhomogeneous, low‐conductivity (<5 S/m) structures. It is applied to cylinders and spheres, and numerical results are given for electrical properties that are representative of some tissues, or of cells embedded either in saline solution or a tissue matrix. Surface currents on spherical cell boundaries are estimated and compared with thermal noise due to ion motion.
On the cyclotron resonance model of ion transport
Authors: Sandweiss Jack
Published: February 2006

The cyclotron‐resonance model, which has been suggested as an explanation of a purported enhancement of transport of ions through the membranes of cells exposed to weak, lowfrequency‐modulated RF fields, is shown to be inconsistent with basic physical principles. Under the conditions of the model, in which the ions are presumed to circulate under the constraint of the earth's magnetic field, the radii of gyration of the ions would approximate 50 m and, thus, are much larger than the cells. Moreover, from general considerations, the collision‐damping time of such ions is expected to be less than 10−10 s, much smaller than the times of the order of 10−2 s, shown to be necessary if the conditions for low‐frequency resonance are to be satisfied.
Use of a spread sheet to calculate the current‐density distribution produced in human and rat models by low‐frequency electric fields
Authors: Hart Francis X.
Published: February 2006

The current‐density distribution produced inside irregularly shaped, homogeneous human and rat models by low‐frequency electric fields is obtained by a two‐stage finite‐difference procedure. In the first stage the model is assumed to be equipotential. Laplace's equation is solved by iteration in the external region to obtain the capacitive‐current densities at the model's surface elements. These values then provide the boundary conditions for the second‐stage relaxation solution, which yields the internal current‐density distribution. Calculations were performed with the Excel spread‐sheet program on a Macintosh‐II microcomputer. A spread sheet is a two‐dimensional array of cells. Each cell of the sheet can represent a square element of space. Equations relating the values of the cells can represent the relationships between the potentials in the corresponding spatial elements. Extension to three dimensions is readily made. Good agreement was obtained with current densities measured on human models with both, one, or no legs grounded and on rat models in four different grounding configurations. The results also compared well with predictions of more sophisticated numerical analyses. Spread sheets can provide an inexpensive and relatively simple means to perform good, approximate dosimetric calculations on irregularly shaped objects.
Electric fields induced by low frequency magnetic fields in inhomogeneous biological structures that are surrounded by an electric insulator
Authors: Polk C. , Song J. H.
Published: February 2006

Electric fields induced by low‐frequency magnetic fields into inhomogeneous structures, which have electric conductivities and dielectric permittivities of typical biological substances, are evaluated. Closed‐form approximate and numerical solutions are obtained for nonconcentric cylinders with different electric properties (such as bone embedded in muscle), which are surrounded by a good electrical insulator (such as air). It is shown that even a single inhomogeneity in an otherwise homogenous cylinder, which is exposed to a uniform, axially directed magnetic field, can lead to substantial deviations from the direction and distribution of the induced electric field that would exist in the homogenous cylinder. Thus the induced field is not everywhere circumferential, nor does its magnitude at all angular positions increase linearly with the radial distance. Radially and circumferentially directed field components depend on size, electrical properties, and eccentricity of the inhomogeneities. Equations as well as graphical presentations are given that describe the induced fields when the enclosed inhomogeneities consist either of eccentrically located single cylinders or pairs of coaxial cylinders with different electrical conductivities or dielectric permittivities.
Exposure of frog hearts to CW or amplitude‐modulated VHF fields: Selective efflux of calcium ions at 16 Hz
Authors: Schwartz Jean‐Louis , House Dennis E. , Mealing Geoffrey A. R.
Published: February 2006

Isolated frog hearts were exposed for 30‐min periods in a Crawford cell to a 240‐MHz electromagnetic field, either continuous‐wave or sinusoidally modulated at 0.5 or 16 Hz. Radiolabeled with calcium (45Ca), the hearts were observed for movement of Ca2+ at calculated SARs of 0.15, 0.24, 0.30, 0.36, 1.50, or 3.00 mW/kg. Neither CW radiation nor radiation at 0.5 Hz, which is close to the beating frequency of the frog's heart, affected movement of calcium ions. When the VHF field was modulated at 16 Hz, a field‐intensity‐dependent change in the efflux of calcium ions was observed. Relative to control values, ionic effluxes increased by about 18% at 0.3 mW/kg (P <.01) and by 21% at 0.15 mW/kg (P <.05), but movement of ions did not change significantly at other rates of energy deposition. These data indicate that the intact myocardium of the frog, akin to brain tissue of neonatal chicken, exhibits movement of calcium ions in response to a weak VHF field that is modulated at 16 Hz.
Evaluation of changes in diatom mobility after exposure to 16‐Hz electromagnetic fields
Authors: Reese J. A. , Frazier M. E. , Morris J. E. , Buschbom R. L. , Miller D. L.
Published: February 2006

The effect of a 16‐Hz electromagnetic field on the mobility of the diatom Amphora coffeaformis was examined on agar plates that contained no added calcium and also on agar plates containing 0.25 or 2.5 mM exogenous Ca2+. Exposure conditions consisted of an ac field of 16 Hz with an amplitude of 20.9 μT parallel to the horizontal component of the dc field (BH = 20.9 μT, where Bv = 0). To assess results, the percentage of diatoms that moved a distance greater than their body length was determined. We observed the field‐associated increase in diatom motion at 0.25 mM Ca++, which was previously reported in the literature. Although the magnitude of the effect at 16 Hz was significant, the percentage of cells that moved was not sufficiently reproducible to allow examination for frequency dependence.
Extremely‐low‐frequency and very‐low‐frequency magnetic fields emitted by video display units
Authors: Tofani S. , D'Amore G.
Published: February 2006

Extremely‐low‐frequency (ELF) and very‐low‐frequency (VLF) magnetic fields as emitted by monochrome and multichrome video display units (VDUs) were measured for their frequency domains. The rms magnetic‐flux densities (MFDs) were measured as a function of distance from all six sides of VDUs of four types. The MFDs at a distance of 30 cm from the screen (defined as the operator's position) were between 0.06 and 0.6 μT in the ELF range and between 0.02 and 0.06 μT in the VLF range. The contribution of harmonics to the total MFD was the same for both frequency ranges, less than 6%. For the first three harmonics, the MFD of each higher harmonic was one‐half that of the immediately lower harmonic.
Astrocytoma risk related to job exposure to electric and magnetic fields
Authors: Mack Wendy , Preston‐Martin Susan , Peters John M.
Published: February 2006

To investigate the association between occupational exposure to low‐frequency electric and magnetic (EM) fields and risk of brain tumors, a study was performed in Los Angeles County on 272 male adults with primary intracranial gliomas or meningiomas and 272 neighborhood controls. Complete occupational histories were collected. Risk associated with employment for more than 10 years in jobs that are presumed to entail exposure to EM fields was computed for various histological groupings. A nonsignificantly elevated risk of 1.7 was found for gliomas (all types pooled: 95% confidence interval 0.7–4.4), and a nonsignificantly reduced risk of 0.3 (95% confidence interval 0.03–3.2) was found for meningiomas. For astrocytomas, which form a subtype of the gliomas, a significantly elevated risk of 10.3 (95% confidence interval 1.3–80.8) was found; a significant upward trend (P = .01) of tumor incidence with increasing length of employment was observed. Most astrocytoma patients who worked in occupations involving exposure to EM fields were electricians or electrical engineers.
Ouabain inhibition of kidney ATPase is altered by 9.14 GHz radiation
Authors: Brown H. D. , Chattopadhyay S. K.
Published: February 2006

At each of several stabilized temperatures between 7.0 and 43.8 °C, increases in dog‐kidney, Na+ −, K+‐ATPase catalytic activity were usually observed in association with exposure for 5 min to 9.14 GHz CW microwave radiation in a thin tubular reactor. However, at 24.9 °C, a 23% decrease occurred. Comparisons of activity of ouabain‐inhibited reactions revealed that the efficacy of the cardiac glycoside as an inhibitor of ATPase activity was severely diminished by the microwave field. The ouabain‐site control mechanism may be a specific microwave target at this exposure frequency. Experimental results can be interpreted in terms of molecular structural changes or direct energy input. The estimated SAR of energy that was incident on preparations is 20 W/kg.
Calcium uptake by leukemic and normal T‐lymphocytes exposed to low frequency magnetic fields
Authors: Lyle Daniel B. , Wang Xinghua , Ayotte Robert D. , Sheppard Asher R. , Adey W. Ross
Published: February 2006

Calcium‐ion uptake by normal and leukemia lymphocytes increased during a 30‐min exposure to a 13.6 Hz, sinusoidal magnetic field at 20 μT peak. The time‐varying field was horizontal and parallel to a 16.5 μT component of the ambient static magnetic field. The uptake of 45Ca2+ increased 102% in a line of murine, cytotoxic T‐lymphocytes (C57B1/6‐derived CTLL‐1), increased 126% in freshly‐isolated spleen lymphocytes (C57B1/6 mice), and increased 75% in a line of lymphoma cells (C57B1/6‐derived EL4). In contrast, there was no effect when the same field was applied for 30 min immediately before—as opposed to during—incorporation of calcium ions. When spleen lymphocytes were exposed during incubation with 45Ca2+ to a 60 Hz magnetic field at 20 μT peak, a small but statistically significant increase (37%) in uptake of the labeled ions occurred. These results indicate that weak, alternating magnetic fields might affect calcium‐dependent functions of normal and leukemic lymphocytes.
Millimeter‐wave effects on electric activity of crayfish stretch receptors
Authors: Khramov R. N. , Sosunov E. A. , Koltun S. V. , Ilyasova E. N. , Lednev V. V.
Published: February 2006

The effects of super high frequency (SHF) microwaves (34–78 GHz) on rates of spontaneous firing of the slowly adapting, stretch‐receptor neurons of crayfish were studied. Initially, irradiation of continuously perfused, fluid‐cooled preparations at power densities to 250 mW/cm2 caused a transient decrease in the rate of spontaneous firing (the dynamic response). Subsequently, with extinction of the SHF field, the rate of firing increased, finally stabilizing at pre‐exposure levels (stationary phase). Rates of firing also increased when the receptor muscle was stretched, and they were inversely correlated with small, field‐induced increases of temperature (∼1.5°C). The response to SHF radiation did not depend on frequency if temperature of the medium was constant. No resonant peaks were found when the millimeter range of frequencies was scanned.
Cancer promotion in a mouse‐skin model by a 60‐Hz magnetic field: II. Tumor development and immune response
Authors: McLean Jack R. N. , Stuchly Maria A. , Mitchel Ronald E. J. , Wilkinson Diana , Yang H. , Goddard Michael , Lecuyer David W. , Schunk Michael , Callary Eva , Morrison David
Published: February 2006

This paper describes preliminary findings on the influence of 60‐Hz (2‐mT) magnetic fields on tumor promotion and co‐promotion in the skins of mice. The effect of magnetic fields on natural killer (NK) cell activity in spleen and blood was also examined. Groups of 32 juvenile female mice were exposed to the magnetic field as described in part I. The dorsal skin of all animals was treated with a subthreshold dose of the carcinogen 7, 12‐dimethylbenz(a)anthracene (DMBA). One week after the treatment, two groups were sham exposed (group A) or field exposed at 2 mT (group B) 6 h/day for 21 weeks, to test whether the field would act as a tumor promoter. No tumors developed in these two groups of mice. To test whether the magnetic field would modify tumor development by directly affecting tumor growth or by suppressing immune surveillance, two additional groups of mice were treated weekly with the tumor promoter 12–0‐tetradecanoylphorbol‐13‐acetate (TPA) and then either sham exposed (group C) or field exposed (group D). The time to appearance of tumors was shorter (but not statistically so) in the group exposed to magnetic fields and TPA. Some differences in NK cell activity and spleen size were observed between the sham‐ and field‐exposed groups.
In vitro exposure parameters with linearly and circularly polarized elf magnetic fields
Authors: Misakian Martin
Published: February 2006

A comparison is made of induced current densities, electric fields, and rates of energy deposition during in vitro studies with linearly and circularly polarized, extremely low frequency magnetic fields for a cylindrical volume of culture medium.
Transcription in Drosophila melanogaster salivary gland cells is altered following exposure to low‐frequency electromagnetic fields: Analysis of chromosome 3R
Authors: Goodman Reba , Weisbrot David , Uluc Alun , Henderson Ann
Published: February 2006

The use of the transcription autoradiographic method permits identification of nascent RNA chains directly on identifiable regions of Drosophila salivary gland chromosomes. Changes in transcriptional activity at 13 defined regions of the right arm of chromosome 3 (3R) were observed following 20‐min exposures of salivary glands to five different extremely low frequency (ELF) electromagnetic (EM) fields. Changes in translational patterns were also induced by the ELF EM fields in exposed cells. Differences included an increase in over‐all polypeptide synthesis as well as in the number of polypeptides resolved in cells exposed to EM fields. © 1992 Wiley‐Liss, Inc.
An analysis of associations between social class and ambient magnetic fields in metropolitan melbourne
Authors: Salzberg M. R. , Farish S. J. , Delpizzo Vincent
Published: February 2006

In the course of a study on residential magnetic‐field exposure, some incidental data were obtained that bear on the issue of confounding of magnetic field exposure by social class. We have explored the possibility that the magnetic flux density of 50 Hz fields measured in Melbourne streets is correlated with a number of variables that index the socio‐economic status of the neighborhood. We have examined also for a correlation between field‐intensity levels and sums of some or all of the indicators, which were weighted to provide an overall score on socio‐economic status. Although some of the indexes were weakly, but significantly, correlated with environmental levels of magnetic fields, the combined indices were not. These results indicate that socio‐economic status is not likely to be a confounder in epidemiological studies of residential exposure to ELF magnetic fields in Melbourne. © 1992 Wiley‐Liss, Inc.
An integrated ELF magnetic‐field generator and incubator for long‐term in vitro studies
Authors: Jones Robert A. , Sheppard Asher R.
Published: February 2006

Long‐term studies of the effects of low‐frequency magnetic fields on cells in culture require an incubator that is free of contaminating magnetic fields and that provides automatic control of exposure duration, uniform applied fields, a uniform and well‐controlled environmental temperature, and high reliability of the total system. We describe a dual‐incubator system in which the enclosed solenoid of either unit can provide a sham exposure while the other generates a magnetic induction of up to 500 μT. Each solenoid‐incubator unit contains an enclosed rack that can hold as many as 140 petri dishes for culturing cells; each unit is heated radiantly by circulating warm water. Field‐exposure conditions and temperatures are continuously monitored and controlled by a microcomputer. © 1992 Wiley‐Liss, Inc.
Alternative functional relationships between ELF field exposure and possible health effects: Report on an expert workshop
Authors: Morgan M. Granger , Nair Indira
Published: February 2006

If exposure to 60 Hz fields poses risks to public health, the relationship between exposure and risk may involve something other than the product of field strength and time. Such alternative possible relations, or “effects functions,” are of great interest to epidemiologists, engineers, risk analysts, and regulators. A structured survey and workshop were used to explore whether leading researchers in bioelectromagnetics share similar views about alternative possible effects functions. Substantial agreement was found about several effects functions in a few specific contexts such as calcium‐ion efflux and cell signaling, and biosynthesis pathways. No significant agreement emerged in many other contexts. No effects function possibilities were ruled out. Further effort of this sort was judged unlikely to yield greater consensus until more complete scientific understanding becomes available. However, a series of structured workshops on research planning and priority setting were judged to hold great potential for useful results. 1992 Wiley‐Liss, Inc.
Rats are not aversive when exposed to 60‐Hz magnetic fields at 3.03 mT
Authors: Lovely R. H. , Creim J. A. , Kaune W. T. , Miller M. C. , Phillips R. D. , Anderson L. E.
Published: February 2006

Thirty‐two male rats were tested in two replicates of an experiment to determine whether body currents induced by 60‐Hz magnetic fields might lead to avoidance behavior comparable to that which results from exposure to strong 60‐Hz electric fields. The test apparatus was a two‐compartment Plexiglas® shuttlebox enclosed in a sound‐attenuating plywood chamber, which in turn was encompassed by two copper bus bars that, when energized, served as a source of 60‐Hz magnetic fields. Location of the rat, and traverse activity in the shuttlebox were monitored by nine infra‐red photo detectors equally spaced along the length of the apparatus. Rats were divided into 2 groups: 1 group of rats (n = 8 per group per replicate) was sham exposed while rats in the other group (n = 8 per group per replicate) were exposed to a 3.03 mT (30.3 G), 60‐Hz magnetic field whenever they traversed to or were located on the side (L or R) predetermined as the exposed side. To control artifact incident to side preference, the side exposed (L or R) was alternated over the exposed rats. Each rat was tested individually in a 1‐h session. A 2‐factor ANOVA (exposed vs. control, replicate 1 vs. replicate 2) failed to reveal any significant effects due to either factor or to an interaction between factors. These data demonstrate that rats do not avoid exposure to 60‐Hz magnetic fields at a flux density of 3.03 mT and further imply that the avoidance by rats of high level 60‐Hz electric fields is mediated by something other than the internal body currents induced by the exposure. 1992 Wiley‐Liss, Inc.
Effects of 45‐Hz magnetic fields on the functional state of the human brain
Authors: Lyskov Evgeny B. , Juutilainen Jukka , Jousmäki Veikko , Partanen Juhani , Medvedev Sviatoslav , Hänninen Osmo
Published: February 2006

The influence of sinusoidal 45‐Hz magnetic fields on the brain functions of 20 volunteers was investigated in a double‐blind study using spectral analysis of EEG and measurements of Omega potentials and reaction time (RT). The field strength was 1,000 A/m (1.26 mT) and the duration of exposure was 1 h. Ten volunteers were exposed to a continuous field and ten received an intermittent exposure (1 s on/1 s off). Each person received one real and one sham exposure. One half of the volunteers got the real exposure first and the sham treatment after at least 24 h. For the rest, the sequence was inverse. The measurements of EEG, omega potentials and RT were performed before and after each exposure. Several statistically significant changes were observed, most of them after intermittent exposure. In the EEG, an increase of alpha (7.6–13.9 Hz) activity and a decrease of delta (1.5–3.9 Hz) activity were observed. β waves (14.2–20 Hz) increased in the frontal derivations as did the total power in occipital derivations. The mean and peak frequencies of EEG increased mainly in the frontal derivations. No direct effects on RT were seen. Learning to perform the RT test (decrease of RT in repeated trials), however, seemed to be affected by the exposure. The persons who received real exposure first learned more slowly than those who got sham exposure first. Further experiments are necessary to confirm the findings and for understanding the mechanisms of the effects. © 1993 Wiley‐Liss. Inc.
Misclassification of ELF occupational exposure resulting from spatial variation of the magnetic field
Authors: Delpizzo Vincent
Published: February 2006

The adequacy of a single hip‐ or chest‐worn magnetic field dosimeter to reliably classify subjects with respect to their occupational ELF magnetic field exposure is investigated. Hip‐worn dosimeters consistently underestimate both whole‐body average exposure and head exposure, tentatively regarded here as two possible definitions of the “true” exposure measurement. The approximate resulting bias in the relative risk estimate in hypothetical case‐control studies is evaluated. A chest‐worn dosimeter is found to be generally superior to a hip‐worn one in assessing exposure during the occupational tasks considered here. © 1993 Wiley‐Liss. Inc.
Design and characterization of a system for exposure of cultured cells to extremely low frequency electric and magnetic fields over a wide range of field strengths
Authors: Mullins Roland D. , Sisken Jesse E. , Hejase Hassan A. N. , Sisken Betty F.
Published: February 2006

A system is described that is capable of producing extremely low frequency (ELF) magnetic fields for relatively short‐term exposure of cultured mammalian cells. The system utilizes a ferromagnetic core to contain and direct the magnetic field of a 1,000 turn solenoidal coil and can produce a range of flux densities and induced electric fields much higher than those produced by Helmholtz coils. The system can generate magnetic fields from the microtesla (μT) range up to 0.14 T with induced electric field strengths on the order of 1.0 V/m. The induced electric field can be accurately varied by changing the sample chamber configuration without changing the exposure magnetic field. This gives the system the ability to separate the bioeffects of magnetic and induced electric fields. In the frequency range of 4–100 Hz and magnetic flux density range of 0.005–0.14 T, the maximum total harmonic distortion of the induced electric field is typically less than 1.0%. The temperature of the samples is held constant to within 0.4°C by constant perfusion of warmed culture medium through the sample chamber. © 1993 Wiley‐Liss, Inc.
Action of 50 Hz magnetic fields on neurite outgrowth in pheochromocytoma cells
Authors: Blackman C. F. , Benane S. G. , House D. E. , Pollock M. M.
Published: February 2006

This study tests the capacity of 50 Hz magnetic and electric fields to stimulate neurite outgrowth in PC‐12D cells, a cell line which originated from a pheochromocytoma in rat adrenal medulla. The cells were plated on collagen‐coated, plastic petri dishes and exposed to sinusoidal 50 Hz magnetic fields for 22 h in a 5% CO2 incubator at 37°C. Two 1,000 turn coils, 20 cm in diameter, were assembled in a Helmholtz configuration to generate a magnetic field in a vertical orientation, thereby inducing a companion electric field in the dish with intensity proportional to radius. A magnetic‐field shield housed the control samples in the same incubator. Total cells and number of cells with neurites at least as long as one cell diameter or having a growth cone were counted within a radius of 0.3 cm of the dish center and within an annulus of 1.7–1.8 cm radii in 60 mm dishes, at 3.6 cm radius in 100 mm dishes, and between 1.9 and 2.1 cm radii in the outer well of organ culture dishes, which are physically separated into two concentric wells. Sham exposure demonstrated no difference in percentage of cells with neurites between the exposed and control locations in the incubator. Exposures were done at 4.0. 8.9, 22, 29, 40, 120, 236, and 400 milliGauss (mG). At dish radii of 1.7–1.8 cm in the 60 mm dishes these magnetic flux densities induced electric fields of 1.1, 2.5, 5.9, 8.1, 11, 33, 65, and 110 μV/m, respectively, while within a radius of 0.3 cm, the induced electric fields were less than 0.2, 0.4, 1.0, 1.5, 1.9, 6.0, 11, and 19 μV/m, respectively. For other dishes, the larger radii produced proportionally larger induced electric fields. At each field strength, there were two control dishes and four to nine exposed dishes: 100 or more cells were counted at each location on the dishes. The results demonstrate that magnetic fields stimulate neurite outgrowth in a flux‐density‐dependent manner between 22 and 40 mG, reaching an apparent stimulation plateau between 40 and 400 mG; no effects were seen at 8.9 mG or lower. There was no apparent neurite stimulation due to the electric field. Although relatively low intensity (≫22mG) magnetic fields alone can stimulate a morphological response in a cell which is normally stimulated by nerve growth factor molecules binding to membrane receptors, the chemical basis of this response is unknown. © 1993 Wiley‐Liss. Inc.
Influence of 50 Hz electric and magnetic fields on the human heart
Authors: Korpinen L. , Partanen J. , Uusitalo A.
Published: February 2006

This investigation studied the effect of 50 Hz electric and magnetic fields on the human heart. The electrocardiograms of 27 transmission‐line workers and 26 male volunteers were recorded with a Holter recorder both in and outside the fields. The measurements took from half an hour to a few hours. The electric field strength varied from 0.14 to 10.21 kV/m and the magnetic flux density from 1.02 to 15.43 μT.

Analysis of the ECG recordings showed that extrasystoles or arrhythmias were as frequent outside the field as in the field. In some cases a small decrease in heart rate was observed after field exposure. © 1993 Wiley‐Liss, Inc.
Pretreatment of rats with pulsed electromagnetic fields enhances regeneration of the sciatic nerve
Authors: Kanje Martin , Rusovan Ana , Sisken Betty , Lundborg Göran
Published: February 2006

Regeneration of the sciatic nerve was studied in rats pretreated in a pulsed electromagnetic field (PEMF). The rats were exposed between a pair of Helmholtz coils at a pulse repetition rate of 2 pps at a field density of 60 or 300 μT. The PEMF treatment was then discontinued. After an interval of recovery, regeneration of the sciatic nerve was initiated by a crush lesion. Regeneration of sensory fibers was measured by the “pinch test” after an additional 3–6 days. A variety of PEMF pretreatments including 4 h /day for 1–4 days or exposure for 15 min/day during 2 days resulted in an increased regeneration distance, measured 3 days after the crush lesion. This effect could be demonstrated even after a 14‐day recovery period. In contrast, pretreatment for 4 h/day for 2 days at 60 μT did not affect the regeneration distance. The results showed that PEMF pretreatment conditioned the rat sciatic nerve in a manner similar to that which occurs after a crush lesion, which indicates that PEMF affects the neuronal cell body. However, the mechanism of this effect remains obscure. © 1993 Wiley‐Liss, Inc.
Influence of weak static and 50 Hz magnetic fields on the redox activity of cytochrome‐C oxidase
Authors: Nossol Bruno , Buse Gerhard , Silny Jiri
Published: February 2006

The effects of static and 50 Hz magnetic fields on cytochrome‐C oxidase activity were investigated in vitro by strictly controlled, simultaneous polarographic measurements of the enzyme's high‐ and low‐affinity redox reaction. Cytochrome‐C oxidase was isolated from beef heart. Control experiments were carried out in the ambient geomagnetic and 50 Hz magnetic fields at respective flux densities of 45 and 1.8 μT. The experimentally applied fields, static and time‐varying, were generated by Helmholtz coils at flux densities between 50 μT and 100 mT. Exposures were timed to act either on the combined enzyme‐substrate interchange or directly on the enzyme's electron and proton translo‐cations. Significant changes as high as 90% of the overall cytochrome‐C oxidase activity resulted during exposure (1) to a static magnetic field at 300 μT or 10 mT in the high‐affinity range, and (2) to a 50 Hz magnetic field at 10 or 50 mT in the low‐affinity range. No changes were observed at other flux densities. After exposure to a change‐inducing, static or time‐varying field, normal activity returned. © 1993 Wiley‐Liss. Inc.
Synergistic effects of ionizing radiation and 60 Hz magnetic fields
Authors: Hintenlang David E.
Published: February 2006

Experiments designed to evaluate the synergistic production of clastogenic effects by ionizing radiation and 60 Hz magnetic fields were performed using human lymphocytes from peripheral blood. Following exposure to ionizing radiation, cells were cultured in 60 Hz magnetic fields having field strengths up to 1.4 mT. Cells exposed to both ionizing radiation and 60 Hz magnetic fields demonstrated an enhanced frequency of near tetraploid chromosome complements, a feature not observed following exposure to only ionizing radiation. The results are discussed in the context of a multiple‐stage model of cellular transformation, employing both initiating and promoting agents. © 1993 Wiley‐Liss. Inc.
Effect of electromagnetic stimulation with different waveforms on cultured chick tendon fibroblasts
Authors: Guzelsu N. , Salkind A. J. , Shen X. , Patel U. , Thaler S. , Berg R. A.
Published: February 2006

An energy efficient electromagnetic stimulator device for fracture healing was compared to a commercially available device in stimulating cell growth in tissue cultures. The energy efficient device, which conserves energy by using a bidirectional time‐dependent magnetic wave form, and the commercially available stimulator, which uses a unidirectionaltime‐dependent magnetic wave form, were tested on chick tendon fibroblasts in primary culture. Comparing non‐stimulated control and cells electromagnetically stimulated with unidirectional and bidirectional waveforms showed that at the growth phase between days 2 and 3, both electrical stimulation techniques increased cell division as measured by DNA synthesis. When cells were dividing rapidly, collagen synthesis was reduced. When the cells reached the confluence there was no difference among the groups (control, unidirectionally stimulated, and bidirectionally stimulated) in terms of number of cells or collagen produced. © 1994 Wiley‐Liss, Inc.
Rhesus monkey behavior during exposure to high‐peak‐power 5.62‐GHz microwave pulses
Authors: D'andrea John A. , Thomas Alfred , Hatcher Donald J.
Published: February 2006

Limits on the exposure to high‐peak‐power, short‐duration microwave pulses have only recently been adopted. Additional data, however, are needed to understand the effects that may be produced by exposure to high‐peak‐power pulsed microwaves. Four male rhesus monkeys (Macaca mulatta) were trained on an operant task for food pellet reward to investigate the behavioral effects of very high‐peak‐power 5.62 GHz microwaves. The operant task required monkeys to pull one plastic lever on a variable interval schedule (VI‐25 s) and then respond to color signals and pull a second lever to obtain food. The monkeys were conditioned to perform a color discrimination task using one of three colors displayed by a fiber‐optic cable. A red signal was the discriminative stimulus for responding on the first lever. A response on the second lever when a green signal was presented (1 s duration) delivered a food pellet. If a response on the second lever was made in the presence of a white signal, a 30‐s timeout occurred. While performing the behavioral task, the monkeys were exposed to microwave pulses produced by either a military radar (FPS‐26A) operating at 5.62 GHz or the same radar coupled to a Stanford linear energy doubler (SLED) pulse‐forming device (ITT‐2972) that enhanced peak power by a factor of nine by adding a high power pulse to the radar pulse. The effects of both types of pulses were compared to sham exposure. Peak field power densities tested were 518, 1270, and 2520 W/cm2 for SLED pulses and 56, 128, and 277 W/cm2 for the radar pulses. The microwave pulses (radar or SLED) were delivered at 100 pps (2.8 μs radar pulse duration, ≈ 50 ns SLED pulse duration) for 20 min and produced averaged whole‐body SARs of 2,4, or 6 W/kg. Compared to sham exposures, significant alterations of lever responding, reaction time, and earned food pellets occurred during microwave exposure at 4 and 6 W/kg but not 2 W/kg. There were no differences between radar or SLED pulses in producing behavioral effects. ©1994 Wiley‐Liss, Inc.

This is a US Government work and, as such, is in the public domain in the United States of America.
Alteration of life span of mice chronically exposed to 2.45 GHz CW microwaves
Authors: Liddle Charles G. , Putnam Julia P. , Huey Ora P.
Published: February 2006

Female CD 1 mice were exposed from the thirty‐fifth day of age for the remainder of their lives to 2.45 GHz, CW‐microwave radiation at a power density of 3 or 10 m W/cm2 (SAR = 2.0 or 6.8 W/kg). Exposures took place 1 h/day, 5 day/week in an anechoic chamber at an ambient temperature of 22 °C and a relative humidity of 50%. There were 25 animals in each exposure group, and an equal number of controls were concurrently sham exposed. The average life span of animals exposed at 10 mW/cm2 was significantly shorter than that of sham‐exposed controls (572 days vs. 706 days; P = .049; truncation >20%). In contrast, the average lifespan of the animals exposed at 3 mW/cm2 was slightly, but not significantly, longer (738 days) than that of controls (706 days). © 1994 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Clarification and application of an ion parametric resonance model for magnetic field interactions with biological systems
Authors: Blanchard J. P. , Blackman C. F.
Published: February 2006

Theoretical models proposed to date have been unable to clearly predict biological results from exposure to low‐intensity electric and magnetic fields (EMF). Recently a predictive ionic resonance model was proposed by Lednev, based on an earlier atomic spectroscopy theory described by Podgoretskii and Podgoretskii and Khrustalev. The ion parametric resonance (IPR) model developed in this paper corrects mathematical errors in the earlier Lednev model and extends that model to give explicit predictions of biological responses to parallel AC and DC magnetic fields caused by field‐induced changes in combinations of ions within the biological system. Distinct response forms predicted by the IPR model depend explicitly on the experimentally controlled variables: magnetic flux densities of the AC and DC magnetic fields (Bacand Bdc, respectively); AC frequency (fac); and, implicitly, charge to mass ratio of target ions. After clarifying the IPR model and extending it to combinations of different resonant ions, this paper proposes a basic set of experiments to test the IPR model directly which do not rely on the choice of a particular specimen or endpoint. While the fundamental bases of the model are supported by a variety of other studies, the IPR model is necessarily heuristic when applied to biological systems, because it is based on the premise that the magnitude and form of magnetic field interactions with unhydrated resonant ions in critical biological structures alter ion‐associated biological activities that may in turn be correlated with observable effects in living systems. © 1994 Wiley‐Liss, Inc.