bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temporal bisection in rats: The effects of high‐peak‐power pulsed microwave irradiation
Authors: Raslear Thomas G. , Akyel Yahya , Bates Frank , Belt Mike , Lu Shin‐Tsu 
Published: February 2006

AbstractThe effects of high‐peak‐power, pulsed microwaves on a time perception and discrimination task were studied in rats. Exposures were performed with the TEMPO exposure system, which produces an 80 nanosecond pulse with peak‐power levels in excess of 700 megawatts. The ability to expose animals to such fields within a controlled environment is unique. As determined by calorimetry, a maximal, whole‐body‐averaged, specificabsorption rate of 0.072 W/kg was produced. Thus exposures were well below a recommended SAR limit of 0.4 W/kg. Power levels of transmitted microwaves were varied over a 50 dB range to obtain ascending and descending dose‐response functions for each of the behavioral measures. Measures of time perception, response bias, and total trials did not change with power level. Dose‐response effects were observed for discriminability (ability to distinguish between durations), session time, and trial completions (null responses, failures to respond on a trial). Covarying sound and X‐ray exposures produced by TEMPO did not reliably correlate with the observed microwave effects. The observation of repeatable dose‐response effects on discriminability and null responses indicates that the microwave exposures were affecting cognitive function in the rats, particularly the decision‐making process. © 1993 wiley‐Liss, Inc.
Biologic effects of prolonged exposure to ELF electromagnetic fields in rats. I. 50 Hz electric fields
Authors: Margonato Vittoria , Veicsteinas Arsenio , Conti Renato , Nicolini Paolo , Cerretelli Paolo 
Published: February 2006

AbstractA three‐year investigation was conducted on the biological effects of high‐intensity electric field exposures of rats for up to 18% of their life span. Two hundred and forty adult male rats, divided into groups of 20 animals each, were exposed at ground potential for 8 h/ day at 25‐kV/m and 100‐kV/m 50‐Hz electric fields or were sham exposed for 280, 440, and 1240 h. The corresponding ages at sacrifice were 140, 164, and 315 days. An additional group of 40 rats was investigated under similar experimental conditions after 440 h of exposure at floating potential.Independent of exposure duration, mode of grounding, and field strength, no statistical differences in body weight, morphology, and histology of the liver, heart, mesenteric lymph nodes, and blood variables (hematology and serum chemistry) were found in comparison with sham‐exposed animals. Plasma levels of luteinizing hormone (LH), follicle‐stimulating hormone (FSH), and testosterone (TS)at sacrifice varied widely among experimental animals in the same group but did not differ in exposed compared with sham‐exposed rats. A nonsignificant tendency toward a decrease in the testes/body weight ratio was found after 1240 h of exposure. Microscopic examination of a large number of specimens showed no quantitative or qualitative statistical differences in testes alterations either among exposed animals or between exposed and their corresponding sham‐exposed groups. We conclude that 50‐Hz electric field exposure, even of long duration at very high field strengths, does not induce harmful effects on tissues with high cellular turnover rates and does not impair the reproductive function of rats. Moreover, after exposure, all variables investigated were well within the normal physiological range. © 1993 Wiley‐Liss. Inc.
In vitro cytogenetic effects of 2450 MHz waves on human peripheral blood lymphocytes
Authors: Maes A. , Verschaeve L. , Arroyo A. , De Wagter C. , Vercruyssen L. 
Published: February 2006

AbstractCytogenetic analyses were performed on human peripheral blood lymphocytes exposed to 2450 MHz microwaves during 30 and 120 min at a constant temperature of 36.1°C (body temperature). The temperature was kept constant by means of a temperature probe put in the blood sample which gives feedback to a microcomputer that controls the microwave supply. We found a marked increase in the frequency of chromosome aberrations (including dicentric chromosomes and acentric fragments) and micronuclei. On the other hand the microwave exposure did not influence the cell kinetics nor the sister chromatid exchange (SCE) frequency. ©1993 Wiley‐Liss, Inc.
The effect of pulsed microwaves on passive electrical properties and interspike intervals of snail neurons
Authors: Field Aaron S. , Ginsburg Kenneth , Lin James C. 
Published: February 2006

AbstractThe effects of pulsed microwaves (2.45 GHz, 10 μs, 100 pps, SAR: 81.5 kW/kg peak, 81.5 W/kg average) on membrane input resistance and action potential (AP) interval statistics were studied in spontaneously active ganglion neurons of land snails (Helix aspersa), at strictly constant temperature (20.8±.07°C worst case). Statistical comparison with sham‐irradiated neurons revealed a significant increase in the mean input resistance of neurons exposed to pulsed microwaves (P ≪ .05 ). Pulsed microwaves had no visible effect on mean AP firing rate; this observation was confirmed by analysis of interspike intervals (ISIs). Using an integrator model for spontaneously active neurons, we found the net input current to be more variable in neurons exposed to pulsed microwaves. The mean input current was not affected. The standard deviation of ISIs and the autocorrelation of the input current were marginally affected, but these changes were not consistent across neurons. Although the observed effects were less obvious than those reported in other studies, they represent evidence of a direct interaction between neurons and pulsed microwaves, in the absence of macroscopic temperature changes. The data do not suggest a single, specific mechanism for such interaction. © 1993 Wiley‐Liss, Inc.
A model for characterizing residential ground current and magnetic field fluctuations
Authors: Mader D. L. , Peralta S. B. , Sherar M. D. 
Published: February 2006

AbstractThe current through the residential grounding circuit is an important source for magnetic fields; field variations near the grounding circuit accurately track fluctuations in this ground current. In this paper, a model is presented which permits calculation of the range of these fluctuations. A discrete network model is used to simulate a local distribution system for a single street, and a statistical model to simulate unbalanced currents in the system. Simulations of three‐house and ten‐house networks show that random appliance operation leads to ground current fluctuations which can be quite large, on the order of 600%. This is consistent with measured fluctuations in an actual house. © 1994 Wiley‐Liss, Inc.
Sleep inducing effect of low energy emission therapy
Authors: Reite M. , Higgs L. , Lebet J.‐P. , Barbault A. , Rossel C. , Kuster N. , Dafni U. , Amato D. , Pasche B. 
Published: February 2006

AbstractThe sleep inducing effect of a 15 min treatment with either an active or an inactive Low Energy Emission Therapy (LEET) device emitting amplitude‐modulated electromagnetic (EM) fields was investigated in a double‐blind cross‐over study performed on 52 healthy subjects. All subjects were exposed to both active and inactive LEET treatment sessions, with an interval of at least I week between the two sessions. LEET consists of 27.12 MHz amplitude‐modulated (sine wave) EM fields emitted intrabuccally by means of an electrically conducting mouthpiece in direct contact with the oral mucosa. The estimated local peak SAR is less than 10 W/kg in the oral mucosa and 0.1 to 100 mW/kg in brain tissue. No appreciable sensation is experienced during treatment, and subjects are therefore unable to tell whether they are receiving an active or an inactive treatment. In this study the active treatment consisted of EM fields intermittently amplitude‐modulated (sine wave) at 42.7 Hz for 3 s followed by a pause of 1 s during which no EM fields were emitted. During the inactive treatment no EM fields were emitted. Baseline EEGs were obtained and 15 min post‐treatment EEGs were recorded and analyzed according to the Loomis classification.A significant decrease (pairedttest) in sleep latency to stage B2 (−1.78 ± 5.57 min,P= 0.013), and an increase in the total duration of stage B2 (1.15 ± 2.47 min,P= 0.0008) were observed on active treatment as compared with inactive treatment. The deepest sleep stage achieved (B1 to D) following active treatment was also significantly higher than that following inactive treatment (P= 0.040). We conclude 27.12 MHz electromagnetic fields, intermittenly amplitude‐modulated at 42.7 Hz, result in a significant sleep inducing effect in healthy subjects. © 1994 Wiley‐Liss, Inc.
Superimposing spatially coherent electromagnetic noise inhibits field‐induced abnormalities in developing chick embryos
Authors: Litovitz T. A. , Montrose C. J. , Doinov P. , Brown K. M. , Barber M. 
Published: February 2006

AbstractLiving cells exist in an electrically noisy environment. This has led to the so‐called “signal‐to‐noise” problem whereby cells are observed to respond to extremely‐low‐frequency (ELF) exogenous fields that are several orders of magnitude weaker than local endogenous fields associated with thermal fluctuations. To resolve this dilemma, we propose that living cells are affected only by electromagnetic fields that are spatially coherent over their surface. The basic idea is that a significant number of receptors must be simultaneously and coherently activated (biological cooperativity) to produce effects on the biochemical functioning of the cell. However, like all physical detection systems, cells are subject to the laws of conventional physics and can be confused by noise. This suggests that a spatially coherent but temporally random noise field superimposed on a coherent ELF signal will defeat the mechanism of discrimination against noise, and any observed field‐induced bioeffects would be suppressed. An experimental test of this idea was conducted using morphological abnormalities in developing chick embryos caused by electromagnetic field exposure as the endpoint. At an impressed noise amplitude comparable to the ELF field strength (but roughly one‐thousandth of the thermal noise field), the increased abnormality rate observed with only the ELF field present was reduced to a level essentially the same as for the control embryos. © 1994 Wiley‐Liss, Inc.
Correlations among indices of electric and magnetic field exposure in electric utility workers
Authors: Savitz David A. , Ohya Takao , Loomis Dana P. , Senior Russell S. , Dan Bracken T. , Howard Richard L. 
Published: February 2006

AbstractPower‐frequency electric and magnetic fields are known to exhibit marked temporal variation, yet in the absence of clear biological indications, the most appropriate summary indices for use in epidemiologic studies are unknown. In order to assess the statistical patterns among candidate indices, data on 4383 worker‐days for magnetic fields and 2082 worker‐days for electric fields collected for the Electric and Magnetic Field Project for Electric Utilities using the EMDEX meter [Bracken (1990): Palo Alto, CA: Electric Power Research Institute] were analyzed. We examined correlations at the individual and job title group levels among indices of exposure to both electric and magnetic fields, including the arithmetic mean, geometric mean, median, 20th and 90th percentiles, time above lower cutoffs of 20 V/m and 0.2 μT, and time above higher cutoffs of 100 V/m and 2.0 μT. For both electric and magnetic fields, the arithmetic mean was highly correlated with the 90th percentile; moderately correlated with the geometric mean, median, and lower and higher cutoff scores; and weakly correlated with the 20th percentile. Electric and magnetic field indices were generally weakly correlated with one another. Rank‐order correlation coefficients were consistently greater than product‐moment correlation coefficients. Job title group summary scores showed higher correlations among electric field indices and magnetic field indices and between electric and magnetic field indices than was found for individual worker‐days, with only the 20th percentile clearly independent of the others. These results suggest that individuals' exposures are adequately characterized by a measure of central tendency for electric and magnetic fields, such as the arithmetic or geometric mean, and an indicator of a lower threshold or cutoff for each field type, such as the 20th percentile or proportion of time above 20 V/m or 0.2 μT. A single measure of central tendency for each type of field appears to be adequate when exposures are assessed at the job title level. © 1994 Wiley‐Liss, Inc.
Effects of extremely‐low‐frequency magnetic fields on biological magnetite
Authors: Polk Charles 
Published: February 2006

AbstractAdair [Bioelectromagnetics 14:1–4, 1993] writes that “the effects of 60 Hz magnetic fields of 5 μT (50 mG) or less on biological structures holding magnetite (Fe3O4) are shown to be much smaller than those from thermal agitation; hence such interactions cannot be expected to be biologically significant.” This conclusion is questioned, because it appears to be based on a model that probably has very limited validity for pertinent biological systems. Furthermore, biologically plausible parameters can be selected to show that even this particular model does not exclude biologically significant effects of 60 Hz magnetic fields below 5 μT. Reported experimental results indicate effects in mammals of 50 Hz fields at the 1 μT level. © 1994 Wiley‐Liss, Inc.
Exposure of simian virus‐40‐transformed human cells to magnetic fields results in increased levels of T‐antigen mRNA and protein
Authors: Gold Steven , Goodman Reba , Shirley‐Henderson Ann 
Published: February 2006

AbstractIn its integrated form, SV‐40 DNA offers an opportunity to observe the behavior of what is in effect a viral genome within a cellular genome, with transcriptional and translational products that can be clearly distinguished from those of the host cell. Exposure of SV40‐transformed human fibroblasts to a 60 Hz continuous‐wave sinusoidal electromagnetic (EM) field resulted in increased levels of virally derived mRNA and protein of large T‐antigen. These findings provide evidence that a foreign DNA integrated into cells can be affected by EM fields under conditions known to cause increased transcripts from endogenous cellular genes. © 1994 Wiley‐Liss, Inc.
Spreadsheet method for calculating the induced currents in bone‐fracture healing by a low‐frequency magnetic field
Authors: Hart Francis X. 
Published: February 2006

AbstractA commercially available spreadsheet program is used on a microcomputer to calculate the induced current density and electric field patterns produced in a nonhomogeneous, anisotropic model of tissue by a localized, low‐frequency magnetic field source. Specific application is made to coils used to promote the healing of bone fractures in limbs. The variation of the conductivity of the fracture gap during healing causes the induced current density pattern to change correspondingly, whereas the induced electric field remains relatively unchanged. Use of more simplified, isotropic models for the bone and for the soft tissue leads to results that differ significantly from those obtained from the full model. The magnetic field beyond the region of the coils contributes little to the induced currents in the fracture gap if the gap is located near the center of the coils. © 1994 Wiley‐Liss, Inc.
Stochastic resonance as a possible mechanism of amplification of weak electric signals in living cells
Authors: Kruglikov Ilya L. , Dertinger Hermann 
Published: February 2006

AbstractThe most important but still unresolved problem in bioelectromagnetics is the interaction of weak electromagnetic fields (EMFs) with living cells. Thermal and other types of noise pose restrictions in cell detection of weak signals. As a consequence, some extant experimental results that indicate low‐intensity field effects cannot be accounted for, and this renders the results themselves questionable. One way out of this dead end is to search for possible mechanisms of signal amplification. In this paper, we discuss a general mechanism in which a weak signal is amplified by system noise itself. This mechanism was discovered several years ago in physics and is known, in its simplest form, as a stochastic resonance. It was shown that signal amplification may exceed a factor of 1000, which renders existing estimations of EMF thresholds highly speculative. The applicability of the stochastic resonance concept to cells is discussed particularly with respect to the possible role of the cell membrane in the amplification process. © 1994 Wiley‐Liss, Inc.
Design and fabrication of well confined uniform magnetic field exposure systems
Authors: Wilson Bary W. , Caputa Kris , Stuchly Maria A. , Saffer Jeffrey D. , Davis Karl C. , Washam Calvin E. , Washam Lloyd G. , Washam Glenn R. , Wilson Mark A. 
Published: February 2006

AbstractExposure systems that provide good magnetic field uniformity, minimum stray fields, and minimal heating, vibration, and hum, as well as capability for true sham exposure in which current flows in the coils, are needed to determine rigorously the biological effects of weak magnetic fields. Designs based on acrylic polymer coil support structures and twisted pair bifilary coil windings were employed to fabricate several different systems for the exposure of laboratory animals and cell cultures to magnetic fields. These systems exhibit excellent performance characteristics in terms of exposure field uniformity, stray field containment, and exposure field cancellation in the sham exposure mode. A custom‐written computer program was used to determine the best arrangement for coils with regard to field uniformity in the exposure volume and stray field containment. For in vivo exposures, modules were made up of four Merritt four‐coil sets, built into a single structure and positioned to form an octapole with fields directed in the horizontal plane. For in vitro applications, two different coil configurations were selected to produce the vertical fields required. A quadrupole system, comprising modules consisting of two Merritt four‐coil sets arranged side by side to limit stray fields, was built as a prototype. In the second configuration, one Merritt four‐coil set was positioned inside the other to form a concentric coil set. In both in vitro systems, exposure chambers were connected to remote commercial incubators in order to reduce ambient magnetic fields in the exposure volume. An active field cancellation circuit was developed for reducing ambient AC magnetic fields in the in vitro sham exposure chamber, when necessary. These design and fabrication approaches provide systems that offer uniform field exposures and excellent stray field containment when needed and are portable, washable, and relatively inexpensive. © 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.
Blockade of sensory neuron action potentials by a static magnetic field in the 10 mT range
Authors: McLean M. J. , Holcomb R. R. , Wamil A. W. , Pickett J. D. , Cavopol A. V. 
Published: February 2006

AbstractTo characterize the inhibitory effect of a static magnetic field, action potentials (AP) were elicited by intracellular application of 1 ms depolarizing current pulses of constant amplitude to the somata of adult mouse dorsal root ganglion neurons in monolayer dissociated cell culture. During the control period, <5% of stimuli failed to elicit AP. During exposure to an ˜11 mT static magnetic field at the cell position produced by an array of four permanent center‐charged neodymium magnets of alternating polarity (MAG‐4A), 66% of stimuli failed to elicit AP. The number of failures was maximal after about 200‐250 s in the field and returned gradually to baseline over 400–600 s. A direct or indirect effect on the conformation of AP generating sodium channels could account for these results because (I) failure was preceded often by reduction of maximal rate of rise, an indirect measure of sodium current; (2) recovery was significantly prolonged in more than one‐half of neurons that were not stimulated during exposure to the MAG‐4A field; and (3) resting membrane potential, input resistance, and chronaxie were unaffected by the field.The effect was diminished or prevented by moving the MAG‐4A array along the X or Z axis away from the neuron under study and by increasing the distance between magnets in the XY plane. Reduction of AP firing during exposure to the ˜0.1 mT field produced by a MAG‐4A array of micromagnets was about the same as that produced by a MAG‐4A array of the large magnets above. The ˜28 mT field produced at cell position by two magnets of alternating polarity and the ˜88 mT field produced by a single magnet had no significant effect on AP firing. These findings suggest that field strength alone cannot account for AP blockade. © 1995 Wiley‐Liss, Inc.
Intracellular calcium oscillations in a T‐cell line after exposure to extremely‐low‐frequency magnetic fields with variable frequencies and flux densities
Authors: Lindström Ewa , Lindström Per , Berglund André , Lundgren Erik , Mild Kjell Hansson 
Published: February 2006

AbstractLow‐frequency magnetic fields (MF) can increase the cytosolic calcium concentration ([Ca2+]i) in lymphocytes in the same manner as a physiological stimulus such as antibodies directed towards the CD3 complex. In this study, MF with various frequencies and flux densities were used, while [Ca2+]ichanges were recorded using microfluorometry with fura‐2 as a probe. The applied sinusoidal MF induced oscillatory changes of [Ca2+], in the leukemic cell line Jurkat in a manner similar to that seen with stimulation by antibodies. The response at 0.15 mT was over a frequency range from 5 to 100 Hz, with a fairly broad peak having its maximum at 50 Hz. The result of testing increasing flux densities at 50 Hz was a threshold response with no effect below 0.04 mT and a plateau at 0.15 mT. On the basis of the characteristic calcium pattern resulting from an applied MF, we suggest that MF influence molecular events in regular signal transduction pathways of T cells. © 1995 Wiley‐Liss, Inc.
A method for assessing alternative effects functions that uses simulation with EMDEX data
Authors: Morgan M. Granger , Nair Indira , Zhang Jun 
Published: February 2006

AbstractA method for evaluating a variety of alternative biologically plausible effects functions through the use of simulation studies conducted on personal‐monitor exposure data is described. Using magnetic field time series collected with EMDEX instruments, we demonstrate how the method can be used to explore (1) how the outputs from various effects functions simulations compare to the results obtained by assuming that effects are proportional to time average field strength; (2) how the results of epidemiological studies might be used to assess the relative likelihood that each of the alternative effects functions describes biological reality; and (3) how the results might be used to assess possible health risks. Although the available data are sufficient to demonstrate the general method, they are not yet sufficient to support actual discrimination among possible alternatives. The arguments on the use of the method are for illustrative purposes only. © 1995 Wiley‐Liss, Inc.