bluuebunny/crossref_metadata_2025 huggingface dataset:
New experimental technique for detecting the effect of low‐frequency electric fields on enzyme structure
Authors: Greco Guido , Gianfreda Liliana , d'Ambrosio Guglielmo , Massa Rita , Scarfi Maria Rosaria , Scaglione Antonio
Published: February 2006

A new experimental approach has been developed to determine kinetic and thermodynamic parameters of the inactivation of an enzyme under labile conditions both with and without exposure to electrical currents as sources of perturbation. Studies were undertaken to investigate if low‐frequency electric currents can accelerate the thermal inactivation of an enzyme through interactions with dipole moments in enzymatic molecules and through related mechanical stresses. The experiments were conducted with the enzyme acid posphatase. The enzyme was exposed to a 50‐Hz current at different densities (10 to 60 mA/cm2 rms) or to a sinusoidal or square‐wave current at an average density of 3 mA/cm2 and frequencies from, respectively, 50 Hz to 20 kHz and 500 pulses per second (pps) to 50,000 pps. Positive‐control experiments were performed in the presence of a stabilizer or a deactivator. The results indicate that the technique is sensitive to conformational changes that otherwise may be impossible to detect. However, exposure to electric currents under the experimental conditions described herein showed no effects of the currents.
A model to assess personal exposure to ELF magnetic fields from common household sources
Authors: Delpizzo Vincent
Published: February 2006

Emission data are inadequate to characterize the contribution of a source to the total personal extremely‐low‐frequency (ELF) magnetic field exposure. In this paper, a simple model is proposed that takes into consideration the position of the subject with respect to the source and the duration of exposure. The magnetic field is spatially averaged over the whole body of the exposed subject and integrated over time. Exposure is regarded as significant if it approaches or exceeds 400 μT‐h/year. By use of this method, the ELF magnetic fields generated by several household sources were compared with the levels of residential external sources, to assess their relative significance. Some common domestic electrical appliances are found to be responsible for an exposure comparable to that from power lines. When the model is used to assess exposure to electric blankets, apparently conflicting findings may be reconciled.
Optimal experimental design for in vitro studies with ELF magnetic fields
Authors: Misakian Martin , Kaune William T.
Published: February 2006

An experimental arrangement is described that maximizes the dosimetric information that can be obtained during in vitro studies with ELF magnetic fields. The arrangement enables researchers to distinguish between a purely magnetic‐field effect and one that also involves the electric fields and currents induced by the magnetic field.
Microwave irradiation of rats at 2.45 GHZ activates pinocytotic‐like uptake of tracer by capillary endothelial cells of cerebral cortex
Authors: Neubauer Cecelia , Phelan Anne M. , Kues Henry , Lange David G.
Published: February 2006

Far‐field exposures of male albino rats to 2.45‐GHz microwaves (10‐μsec pulses, 100 pps) at a low average power density (10 mW/cm2; SAR ∼2 W/kg) and short durations (30–120 min) resulted in increased uptakes of tracer through the blood‐brain barrier (BBB). The uptake of systemically administered rhodamine‐ferritin complex by capillary endothelial cells (CECs) of the cerebral cortex was dependent on power density and on duration of exposure. At 5 mW/cm2, for example, a 15‐min exposure had no effect. Near‐complete blockade of uptake resulted when rats were treated before exposure to microwaves with a single dose of colchicine, which inhibits microtubular function. A pinocytotic‐like mechanism is presumed responsible for the microwave‐induced increase in BBB permeability.
Effects of a high‐voltage direct‐current transmission line on beef cattle production
Authors: Angell R. F. , Schott M. R. , Raleigh R. J. , Bracken T. D.
Published: February 2006

Two herds of beef cattle were maintained beneath a ±500 kV direct‐current transmission line during a 30‐month period, and were compared with two similar herds maintained away from the transmission line. Exposures of animals under the line were five to 30 times greater than those of control animals, depending on the parameter of interest, with average exposure magnitudes of 5.6 kV/m, 4.1 nA/m2, and 13 k ions/cm3, respectively, for electric field, ion current, and density of ions. Productivity and health status of cows and calves were similar between lines and control treatments. Mean body mass of cows increased with maturity, from 438 kg in 1985 to 496 kg in 1987. Calf gain averaged 0.93 kg per head per day. No unusual sources of mortality were observed. Based on this confinement study, beef cattle permitted to graze in the vicinity of a high‐voltage, direct‐current transmission lines are not expected to experience any decrease in frequency of conception, calving, growth rate, or survival.
The effect of microwave radiation on the stability and formation of gramicidin‐A channels in lipid bilayer membranes
Authors: Sandblom John , Theander Sten
Published: February 2006

The effects of microwaves on the single‐channel kinetics of gramicidin‐A channels in lipid bilayer membranes were examined. Attempts were made to separate thermal and athermal effects by accurate measurements of temperature at the site of the membrane and by relating the measured parameters to their previously characterized temperature dependence. It was found that microwave radiation does not affect single‐channel conductance or channel life time to a degree that is significantly different from that expected of a purely thermal effect. On the other hand, the rate of channel formation is decreased during exposure, which is opposite to that expected of a purely thermal effect. The mechanism of this effect is discussed in terms of the dimerization process of channel formation.
Antibody responses of mice exposed to low‐power microwaves under combined, pulse‐and‐amplitude modulation
Authors: Veyret B. , Bouthet C. , Deschaux P. , de Seze R. , Geffard M. , Joussot‐Dubien J. , le Diraison M. , Moreau J.‐M. , Caristan A.
Published: February 2006

Irradiation by pulsed microwaves (9.4 GHz, 1 μs pulses at 1,000/s), both with and without concurrent amplitude modulation (AM) by a sinusoid at discrete frequencies between 14 and 41 MHz, was assessed for effects on the immune system of Balb/C mice. The mice were immunized either by sheep red blood cells (SRBC) or by glutaric‐anhydride conjugated bovine serum albumin (GA‐BSA), then exposed to the microwaves at a low rms power density (30 μW/cm2; whole‐body‐averaged SAR ∼ 0.015 W/kg). Sham exposure or microwave irradiation took place during each of five contiguous days, 10 h/day. The antibody response was evaluated by the plaque‐forming cell assay (SRBC experiment) or by the titration of IgM and IgG antibodies (GA‐BSA experiment). In the absence of AM, the pulsed field did not greatly alter immune responsiveness. In contrast, exposure to the field under the combined‐modulation condition resulted in significant, AM‐frequency‐dependent augmentation or weakening of immune responses.
Possible mechanism for the influence of weak magnetic fields on biological systems
Authors: Lednev V. V.
Published: February 2006

A physical mechanism is suggested for a resonant interaction of weak magnetic fields with biological systems. An ion inside a Ca2+ ‐binding protein is approximated by a charged oscillator. A shift in the probability of ion transition between different vibrational energy levels occurs when a combination of static and alternating magnetic fields is applied. This in turn affects the interaction of the ion with the surrounding ligands. The effect reaches its maximum when the frequency of the alternating field is equal to the cyclotron frequency of this ion or to some of its harmonics or sub‐harmonics. A resonant response of the biosystem to the magnetic field results. The proposed theory permits a quantitative explanation for the main characteristics of experimentally observed effects.
A system for simultaneous exposure of small animals to 50‐Hz electric and magnetic fields
Authors: Baum J. W. , Kuehner A. V. , Benz R. D. , Carsten A. L.
Published: February 2006

Equipment designed for simultaneous exposure of rodents to 60‐Hz electric and magnetic fields is described. Three identical systems were constructed, each capable of continuous exposure of 256 rats or 640 mice to a nominal electric field at <50 kV/m, and to horizontal and vertical magnetic fields at < 1 mT. Design features, construction details, and results of various tests of the systems are described. Tests were made: of phase relations between electric and magnetic fields; of uniformity of electric and magnetic fields; of changes across time in electric‐field intensity as a result of animals' soiling of cages and various washing routines; of resistance of bedding material during humid and dry conditions; and of acoustic noise due to background, to field‐generation equipment, and to air conditioning equipment. The results demonstrated that fields were effectively generated but that significant and troublesome changes in electric‐field intensity occurred because of cage‐soiling. However, when cages were frequently cleaned, field intensities were consistent from one exposure to another.
Effects of exposure to 30 kV/m, 60‐Hz electric fields on the social behavior of baboons
Authors: Coelho Anthony M. , Easley Stephen Phillip , Rogers Walter R.
Published: February 2006

We tested the hypothesis that exposure to a 30‐kY/m, 60‐Hz electric field produces significant change (stress) in the social behavior of adult male baboons (Papio cynocephalus anubis). One group of eight baboons was exposed to an electric field (12 hours per day, 7 days per week for 6 weeks) while a second group of eight baboons was maintained in a sham‐exposure (control) condition. Exposed subjects and control subjects were compared over three, six‐week experimental periods (pre‐exposure, exposure, and post‐exposure). Performance rates of six categories of social behaviors (passive affinity, active affinity, approach, tension, threat, and attack) and four categories of nonsocial behaviors (forage, manipulate, posture, and stereotypy) were used to compare the two groups. The results of our study indicate that 1) there were no significant differences between the two groups during the pre‐exposure or post‐exposure periods; 2) during the exposure period, experimental and control groups exhibited statistically significant differences in the mean performance rates of three behavior categories; 3) within‐group comparisons across periods indicate that the experimentally exposed group exhibited statistically significant changes in passive affinity, tension, and stereotypy; and 4) changes in behavior performance among the exposed subjects reflect a stress response to the electric field.
The influence of temperature during electric‐ and magnetic‐field‐induced alteration of calcium‐ion release from in vitro brain tissue
Authors: Blackman C. F. , Benane S. G. , House D. E.
Published: February 2006

A technique based on release of calcium ions from in vitro preparations of avian brain tissues has been used by several investigators to demonstrate a biological effect of weak electric and magnetic fields. When the tissues have been exposed to ELF‐modulated, VHF or UHF fields, enhanced release of calcium ions has resulted. In contrast, when the tissues have been exposed directly to an ELF field, outcomes have differed. Both inhibition and enhancement in release of calcium ions have been reported. We now find that either outcome—or a null result—is possible, depending on the temperature of tissue samples before and during exposure. Avian‐brain tissues were exposed to 16‐Hz sinusoidal electromagnetic fields at 14.1 Vrms/m (in air) and 64 nTrms. During 20‐min exposures, as tissue‐sample temperature rose by 0.7 to 2.5 °C to a final temperature of 35, 36, or 37, but not of 38 or 39°C, an enhanced release of ions was observed. When the temperature was stable during exposure (i.e., constant within ±0.3°C) at a final value of 36 or 37, but not of 35 or 38°C, the quantity of ions released was reduced. And when descending by 0.7 to 1.5°C to any final temperature from 35 to 38°C, a null result occurred. These findings may reconcile the apparent disagreement in the direction of a field‐induced response, and they may explain why experimental outcomes have been difficult to confirm in some laboratories. Of greater importance, the findings may also provide insight into the mechanism of the field‐induced phenomenon.
Immediate post‐exposure effects of high‐peak‐power microwave pulses on operant behavior of Wistar rats
Authors: Akyel Yahya , Hunt Edward L. , Gambrill Charles , Vargas Carlos
Published: February 2006

Behavioral effects of high‐peak‐power microwave pulses on Wistar rats were studied by operant schedules. Each of twelve rats that had been trained to press a lever to receive food pellets was assigned randomly in groups of four to three different schedules of reinforcement: fixed‐ratio (FR), variable‐interval (VI), and differential‐reinforcement‐of‐low‐rates (DRL). After achieving a steady baseline performance, each animal was exposed for 10 min to 1.25‐GHz microwave radiation at 1‐MW peak‐power (10‐μs pulse width). Each pulse produced a peak whole‐body SA and SAR of 2.1 J/kg and 0.21 MW/kg. Total doses (SAs) were set to 0.50, 1.5, 4.5, and 14 kJ/kg by adjusting the pulse‐repetition rate. The corresponding time‐averaged whole‐body SARs were 0.84, 2.5, 7.6, and 23 W/kg. A microwave‐transparent animal holder was used to keep the animal's body axis parallel to the E‐field. Exposures at the highest dose caused an average colonic temperature rise of 2.5 °C and these animals failed to respond at all for about 13 minutes after the exposure. Their colonic temperatures had decreased to 1.1 °C, or less, above their pre‐exposure (normal) temperature level when they began to respond. The FR and VI animals failed to reach their baseline levels of performance thereafter, while those on the DRL schedule displayed variable effects. No behavioral effects were found at the lower dose levels. It is concluded that the behavioral perturbations produced by pulsed microwave irradiation were thermal in nature.
Magnetic shielding induces early developmental abnormalities in the newt, Cynops pyrrhogaster
Authors: Asashima Makoto , Shimada Kazunori , Pfeiffer Carl J.
Published: February 2006

Developing larvae of the Japanese newt, Cynops pyrrhogaster, were subjected for 5 days to a shielded environment in which the static magnetic field was about 10,000 times weaker (5 nT) than the geomagnetic norm, which ranges between 30 and 60 μT at the earth's surface. Larvae from non‐cleavage to neurula stages were exposed under shielded or normal (control) conditions and then examined for evidence of developmental abnormalities either 1 day or 20 days after treatment. The magnetic shielding was associated with an increased incidence of somatic defects, especially in larvae that were examined 20 days after shielding. Bi‐headedness and intestinal protrusion were observed in magnetically shielded larvae but not in controls. Other abnormalities more frequently observed in shielded larvae were spinal curvature, malformed eyes, and retarded or blocked development. These data are among the first to illustrate the effects of magnetic‐field deprivation on a developing animal.
Cancer promotion in a mouse‐skin model by a 60‐Hz magnetic field: I. Experimental design and exposure system
Authors: Stuchly Maria A. , Lecuyer David W. , McLean Jack
Published: February 2006

The rationale for selection of an animal model, the experimental design, and the design and evaluation of an exposure system used in studies of 60‐Hz magnetic fields are described. The studies were conceived to assay development of cancer and immune responsiveness in mice exposed to magnetic fields. The exposure system utilized a quadrupole‐coil configuration to minimize stray magnetic fields. Four square‐wound coil provided a uniform field within a volume occupied by 16 animal cages. The magnetic field had a mean flux density of 2 mT that varied less than ±10% within the volume occupied by animals' cages. The flux density decreased to less than 0.1 μT at a distance of 2 m from the coils. In each exposure system 32 animals could be housed in plastic cages.
Electric fields induced in chicken eggs by 60‐Hz magnetic fields and the dosimetric importance of biological membranes
Authors: Miller Douglas L.
Published: February 2006

Chicken eggs are convenient models for observing the effects of inhomogeneities and variations, such as those found in biological membranes and in cellular conductivities, on the distribution of internal electric fields as induced by exposure to magnetic fields. The vitelline membrane separates the yolk, which has a conductivity of 0.26 S/m, from the white, which has a conductivity of 0.85 S/m. A miniaturized probe with 2.4‐mm resolution was used to measure induced fields in eggs placed in a uniform, 1‐mT magnetic field at 60 Hz. The E fields induced in eggs with homogenized contents agreed with expectations based on simple theory. Results were similar to intact eggs unless the probe moved the yolk off‐center, which greatly perturbed the induced fields. A more reproducible arrangement, which consisted of saline‐agar filled dishes with a hole cut for test samples, was developed to enhance definition of electrical parameters. With this test system, the vitelline membrane was found to be responsible for most of the perturbation of the induced field, because it electrically isolates the yolk from the surrounding white. From a theoretical viewpoint, this dosimetry for the macroscopic egg yolk is analogous to the interaction of fields with microscopic cells. These findings may have important implications for research on biological effects of ELF electromagnetic fields, especially for studies of avian embryonic development.
Effects of exposure to a 60‐kV/m, 60‐Hz electric field on the social behavior of baboons
Authors: Easley Stephen Phillip , Coelho Anthony M. , Rogers Walter R.
Published: February 2006

We found in a previously reported study that exposure to a 30‐kV/m, 60‐Hz electric field had significant effects on the social behavior of baboons. However, it was not established whether or not the effects were related specifically to the 30‐kV/m intensity of the field. A new experiment was conducted to determine whether or not exposure to a 60‐Hz electric field at 60 kV/m would produce like changes in the baboons' social behavior. We exposed one group of eight male baboons to an electric field 12 hours a day, 7 days a week, for 6 weeks. A second group of eight animals was maintained under sham‐exposure (control) conditions. Rates of performing on each of six categories of social behavior and on four categories of nonsocial behavior were used as criteria for comparing exposed with unexposed subjects and for within‐group comparisons during three six‐week experimental periods: Pre‐Exposure, Exposure, and Post‐Exposure. The results indicate that (1) during the exposure period, exposed animals exhibited statistically significant differences from controls in means of performance rates based on several behavioral categories; (2) across all three periods, within‐group comparisons revealed that behaviors of exposed baboons were significantly affected by exposure to the electric field; (3) changes in performance levels probably reflect a stress response to the electric field; and (4) the means of response rates of animals exposed at 60 kV/m were higher, but not double, those of animals exposed at 30 kV/m. As in the 30‐kV/m experiment, animals exposed at 60 kV/m exhibited significant differences in performances of Passive Affinity, Tension, and Stereotypy. Mean rates of performing these categories were 122% (Passive Affinity), 48% (Tension), and 40% (Stereotypy) higher in the exposed group than in the control group during exposure to the 60‐kV/m field.
High‐intensity electrostatic‐field exposure system for cultured biological cells
Authors: Obarski Gregory E. , Beckel Charles L.
Published: February 2006

We describe a new system for exposing cultured biological cells that have been plated on coverslips to strong electrostatic fields at magnitudes > 103 V/cm. Techniques are described that make use of mineral oil to render insignificant electrical conduction currents (total leakage current is < 1.0 nA or < 0.1 nA/coverslip), joule heating (< 10−6 W), or current‐induced magnetic fields (< 10−13 T) in regions inhabited by cells. The mineral oil also eliminates a reduction in the strength of the applied field, which otherwise can occur from increased electrode‐to‐medium impedance at the site of application. Thus the applied field is reliably specified in the vicinity of a cell membrane. Control and electrostatic field chambers are housed in a grounded metal incubator. Cylindrical mu‐metal shields can be used to reduce background magnetic fields in each chamber from 40 μT static and ∼ 1 μT ac to, respectively, < 3 μT static and ∼ 100 nT ac. Contamination of cells by impurity atoms that may leach from electrodes was measured by atomic‐absorption spectrophotometry and found to be negligible. Stray magnetic‐ and electric‐field components within the incubator were measured, as were background fields around the laboratory. © 1992 Wiley‐Liss, Inc.
Measurements of potential differences in human subjects induced by motion in a superconducting magnetic field
Authors: Frinak S. , Knight R. A. , Liboff A. R.
Published: February 2006

We have attempted to measure the electromotive forces (emfs) induced in human beings moving at a constant speed in a highly dense magnetic field. Experiments were initially conducted on a set of models, and then directly on human subjects. The models consisted of single circular loops of Tygon tubing (I.D., 0.635 cm; O.D., 0.9525 cm) filled with normal saline solution, with circumferences of 20, 40, 60, 80, and 100 cm. The models were connected to an amplifier via silver/silver‐chloride electrodes. Each saline loop was mounted on a movable platform, with the plane of the loop perpendicular to the platform's axis; the platform was enabled to move at known constant speeds into and out of the bore of a 1.89‐T magnet. The human subjects were then substituted for the saline loops, with the long axis parallel to the direction of motion, and with standard EKG electrodes placed at 180° successively on the ankle, calf, lower thigh, upper thigh, chest, and head. In all cases, for human subjects and models, the peak induced voltage was directly proportional to the speed of movement and the square of the circumference of the bounded cross‐sectional areas. Thus, for the saline loops, the correlation coefficient between induced voltage and circumference was .998, and for human subjects, .947. Under the loose assumption that for equal circumferences the bounded areas in human subjects were equal to those in the circular loops, the induced emfs in human subjects were consistently about 13% greater than those in the loops. At a mean speed of 1.18 m/s, the chest had a peak induced voltage of 260 mV, while the voltage at the ankle had a peak of 19.8 mV. The experimental data were used to estimate the corresponding induced‐current density at the pericardium, 17 mA/m2. We conclude for a human subject moving at constant speed along the body's long axis into a magnetic field that Faraday's law is closely followed for various cross‐sections of the body. Further, in those cases in which the magnetic field and its gradient are not well‐established, one can use saline‐filled loops to estimate approximate values of voltages induced in human subjects. © 1992 Wiley‐Liss, Inc.
Foot currents and ankle SARs induced by dielectric heaters
Authors: Conover David L. , Moss C. Eugene , Murray William E. , Edwards Richard M. , Cox Clinton , Grajewski Barbara , Werren Dwight M. , Smith James M.
Published: February 2006

Data are presented on ankle‐specific SARs and foot currents as a function of strengths of radio‐frequency electromagnetic fields encountered by operators of dielectric heaters. The determination of foot currents was based on near‐field exposures in which reactive coupling dominates, and which can result in substantial SARs in exposed workers. The operators were located less than one wavelength from—usually within one meter of—the dielectric heaters, which generated fields at frequencies from 6.5 to 65 MHz. At distances normally assumed by workers, maximal strengths of electric fields ranged from 104 to 2.4 × 106 V2/m2; maximal strengths of magnetic fields ranged from 5.0 × 10−3 to 33.3 A2/m2. Currents through both feet to ground were measured while operators stood where they normally worked. Maximal currents ranged from 3 to 617 mA, rms. Nearly 27 percent of the dielectric heaters induced foot currents that exceeded the 200‐mA limit that has been proposed for a new ANSI C95.1 standard. Twenty percent of the heaters induced foot currents that exceeded 350 mA. SARs in ankles were calculated from foot currents, and they approximated 5 W/kg at 100 mA, 29 W/kg at 250 mA, and 57 W/kg at 350 mA. The maximal SAR in the ankle was ∼ 176 W/kg at 617 mA. © 1992 Wiley‐Liss, Inc.
A replication study of human exposure to 60‐Hz fields: Effects on neurobehavioral measures
Authors: Cook Mary R. , Graham Charles , Cohen Harvey D. , Gerkovich Mary M.
Published: February 2006

The purpose of this study was to reproduce and extend an earlier investigation of the effects of human exposure to combined, 60‐Hz electric and magnetic fields. This paper presents the neurobehavioral results. Thirty men participated in one training session and four testing sessions. Subjects were randomly assigned to two groups. The 18 subjects in Group I were exposed (9 kV/m, 20 μT) and sham exposed in two counterbalanced orders. In Group II, half of 12 subjects were exposed (9 kV/m, 20 μT) every session, and the remaining half were sham exposed every session. The study was doubly blinded. Measures of cardiac interbeat interval, event‐related brain potentials, and performance were obtained before, during, and after exposures. As in the earliers study, exposure to the combined field resulted in a statistically significantly slowing of heart rate, in changes in late components of eventrelated brain potentials, and in decreased errors on a choice reaction‐time task. In addition, field effects on several other measures approached statistical significance. The physiological measures obtained during exposure indicated that effects were greatest soon after the field was switched on, and again when it was switched off. The data indicate that changes in exposure level may be more important than duration of exposure for producing effects in human beings. © 1992 Wiley‐Liss, Inc.
Dose dependence of acetylcholinesterase activity in neuroblastoma cells exposed to modulated radio‐frequency electromagnetic radiation
Authors: Dutta S. K. , Das K. , Ghosh B. , Blackman C. F.
Published: February 2006

Radio‐frequency electromagnetic radiation (RFR) at 915 and at 147 MHz, when sinusoidally amplitude modulated (AM) at 16 Hz, has been shown to enhance release of calcium ions from neuroblastoma cells in culture. The dose‐response relation is unusual, consisting of two power‐density “windows” in which enhanced efflux occurs, separated by power‐density regions in which no effect is observed. To explore the physiological importance of these findings, we have examined the impact of RFR exposure on a membrane‐bound enzyme, acetylcholinesterase (AChE), which is intimately involved with the acetylcholine (ACh) neurotransmitter system. Neuroblastoma cells (NG108), exposed for 30 min to 147‐MHz radiation, AM at 16 Hz, demonstrated enhanced AChE activity, as assayed by a procedure using 14C‐labeled ACh. Enhanced activity was observed within a time window between 7.0 and 7.5 h after the cells were plated and only when the exposure occurred at power densities identified in a previous report as being effective for altering the release of calcium ions. Thus RFR affects both calcium‐ion release and AChE activity in nervous system‐derived cells in culture in a common dose‐dependent manner. 1992 Wiley‐Liss, Inc.
Effects of a 30 kV/m, 60 Hz electric field on the social behavior of baboons: A crossover experiment
Authors: Easley Stephen Phillip , Coelho Anthony M. , Rogers Walter R.
Published: February 2006

Using a crossover experimental design, we evaluated our earlier findings that exposure to a 30 kV/m, 60 Hz electric field for 12 hours per day, 7 days per week for 6 weeks produced significant changes in the performance rates of social behaviors among young adult male baboons. In the crossover experiment, the former control group was exposed to a 30 kV/m, 60 Hz electric field for 3 weeks. Only an extremely small, incidental magnetic field was generated by the exposure apparatus. We found that electric‐field exposure again produced increases in the performance rates that index Passive Affinity, Tension, and Stereotypy. These findings, combined with results from our other electric‐field experiments, indicate that exposure to strong electric fields, in the absence of associated magnetic fields, consistently produces effects that are expressed as increases in rates of performance of social behaviors in young adult male baboons. 1992 Wiley‐Liss, Inc.
Uniform magnetic fields and double‐wrapped coil systems: Improved techniques for the design of bioelectromagnetic experiments
Authors: Kirschvink Joseph L.
Published: February 2006

A common mistake in biomagnetic experimentation is the assumption that Helmholtz coils provide uniform magnetic fields; this is true only for a limited volume at their center. Substantial improvements on this design have been made during the past 140 years with systems of three, four, and five coils. Numerical comparisons of the field uniformity generated by these designs are made here, along with a table of construction details and recommendations for their use in experiments in which large volumes of uniform intensity magnetic exposures are needed. Double‐wrapping, or systems of bifilar windings, can also help control for the non‐magnetic effects of the electric coils used in many experiments. In this design, each coil is wrapped in parallel with two separate, adjacent strands of copper wire, rather than the single strand used normally. If currents are flowing in antiparallel directions, the magnetic fields generated by each strand will cancel and yield virtually no external magnetic field, whereas parallel currents will yield an external field. Both cases will produce similar non‐magnetic effects of ohmic heating, and simple measures can reduce the small vibration and electric field differences. Control experiments can then be designed such that the only major difference between treated and untreated groups is the presence or absence of the magnetic field. Double‐wrapped coils also facilitate the use of truly double‐blind protocol, as the same apparatus can be used either for experimental or control groups. 1992 Wiley‐Liss, Inc.
Whole‐body microwave dosimetry based on a single, gradient‐layer calorimeter
Authors: Mathur Satnam P. , Akyel Yahya , Lu Shin‐Tsu
Published: February 2006

A simple, cost‐effective, and accurate technique to measure the whole‐body‐averaged specific absorption rate (SAR) in Sprague‐Dawley rat carcasses by a single‐gradient‐layer calorimeter is described. The results of SAR determinations showed a highly linear relation between the average power density of the incident field (1.25 GHz) and the normalized heat loading of the carcasses. 1992 Wiley‐Liss, Inc.
Effects of ELF magnetic fields on biological magnetite
Authors: Adair Robert K.
Published: February 2006

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 that from thermal agitation; hence such interactions cannot be expected to be biologically significant. © 1993 Wiley‐Liss, Inc.
Effects of a 60 Hz magnetic field on central cholinergic systems of the rat
Authors: Lai H. , Carino M. A. , Horita A. , Guy A. W.
Published: February 2006

We studied the effects of an acute (45 min) exposure to a 60 Hz magnetic field on sodium‐dependent, high‐affinity choline uptake in the brain of the rat. Decreases in uptake were observed in the frontal cortex and hippocampus after the animals were exposed to a magnetic field at flux densities ≫ 0.75 mT. These effects of the magnetic field were blocked by pretreating the animals with the narcotic antagonist naltrexone, but not by the peripheral opioid antagonist, naloxone methiodide. These data indicate that the magnetic‐field‐induced decreases in high‐affinity choline uptake in the rat brain were mediated by endogenous opioids in the central nervous systems. © 1993 Wiley‐Liss, Inc.
Effects of microwaves on membranes of hematopoietic cells in their structural and functional organization
Authors: Rotkovská Dolores , Bartoničková Alena , Kautská Jitka
Published: February 2006

The role of cell membranes in stimulating and inhibiting the effects of microwaves was investigated in experiments carried out with a suspension of murine bone marrow cells irradiated with microwaves in vitro [f = 2.45 GHz, CW, specific absorption rate (SAR) = 12 W/kg]. Results obtained by means of a structural probe, 2.4‐TNS, indicate that no structural changes occur in the region of the protein‐lipid interphase under conditions of short‐term irradiation with microwaves that induced temperatures in the range 36–45°C (exposure time 315 and 525 s, respectively). Investigation of one functional parameter—the ability to produce hematopoietic colonies in the spleen after transplantation of the bone marrow irradiated in vitro by microwaves—indicated the possibility of affecting stimulatory and inhibitory effects of microwaves by using a blocker of cell receptors, Trimepranol. The role of microwaves as a physical factor interfering in the process of cell proliferation at the level of receptor regulation is discussed. © 1993 Wiley‐Liss, Inc.
Effect of static magnetic fields on osteoblasts and fibroblasts in vitro
Authors: McDonald Fraser
Published: February 2006

In vitro assays were made of the effect of a static magnetic field of a neodymium magnet on cellular behavior. The cell turnover rate was examined by the incorporation of radioactive thymidine, and anabolic processes were measured by the incorporation of radioactive proline. Cell cultures of fibroblast‐ and osteoblast‐like cells of the neonatal rat calvarium were assayed to determine uptakes of radioactive thymidine and proline; these assays were performed in conjunction with examination of an explant of the rat calvarium. The cells were assayed after exposure to a field for 1‐, 3‐, 5‐, 7‐, and 10‐day periods. Cells were exposed to north and south poles with a pole‐face flux density of 0.61 T; control cultures were exposed to an unmagnetised piece of neodymium. After sham exposure or exposure to the magnetic field, 50 μCuries/ml of culture media of isotope were added to the culture medium. The cultures were returned to an incubator for 6 h. Then, following centrifugation, the supernatant was assayed for radioactivity in a scintillation counter after addition of 3 ml of scintillation fluid. A statistically significant magnetic stimulation of turnover rate and synthesis of fibroblasts was found, but stimulation of osteoblasts did not occur. Conversely, the explants, which represent the osteoblasts and fibroblasts in an organised system, showed a statistically significant inhibition in uptake of the radioactive label. The data indicate both variability and diversity of cellular behaviour, and they accentuate the need for caution in the interpretation of effects of static magnetic fields. © 1993 Wiley‐Liss, Inc.
Evaluating exposure cutpoint bias in epidemiologic studies of electric and magnetic fields
Authors: Wartenberg Daniel , Savitz David A.
Published: February 2006

Epidemiologists who study the association between exposure to electric or magnetic fields and adverse health outcomes often classify their subjects as “exposed” and “unexposed,” and they report results based on an odds ratio. The exposure classification rule—or dichotomy rule—is typically based on a priori assumptions or arbitrary considerations. We show that results may vary substantially with selection of different cutpoints by which to dichotomize exposure. Further, interpretation and comparison of studies is dependent on the choice of cutpoint. We suggest the use of probability plots as a more informative method of data representation. To demonstrate the utility of probability plots. we re‐analyze data reported by Savitz et al. [1988, Am J Epidemiol 128:21–38]. Using a higher exposure cutpoint than that of the original analysis, we obtained larger odds ratios, two of which achieved statistical significance. More important, probability plots of these data showed 1) consistency of results with measures of magnetic fields in both low‐ and high‐poweruse situations, and 2) discordance with results based on measures of electric fields. Given these observations. we recommend further study, especially that focused on the most highly exposed individuals. © 1993 Wiley‐Liss. Inc.
Theoretical study of the resonant behaviour of an ion confined to a potential well in a combination of AC and DC magnetic fields
Authors: Galt Sheila , Sandblom John , Hamnerius Yngve
Published: February 2006

Numerical solutions are presented to the equation of motion for an ion confined to a region of space by a restoring force and subject to DC and AC magnetic fields. We have expanded on the theoretical work of Durney et al. [1988] by including a potential well as a confining factor. This additional term in the equation of motion, being nondissipative, could allow for the buildup of stored energy within the system to a level necessary for a macroscopic resonant phenomenon. Resonant behaviour has been studied, including calculation of the trajectory and energy (kinetic and potential) of a confined ion, with emphases on the appearance of both amplitude and frequency windows. The results are discussed in relation to ion transport through transmembrane channels exposed to magnetic fields. When realistic values of the frictional and restoring‐force coefficients are considered, all predicted resonant behaviour disappears, except at very high field strengths. © 1993 Wiley‐Liss. Inc.
Rats avoid exposure to HVdc electric fields: A dose response study
Authors: Creim J. A. , Lovely R. H. , Weigel R. J. , Forsythe W. C. , Anderson L. E.
Published: February 2006

Rats, given the choice, avoid exposure to alternating current (ac) 60‐Hz electric fields at intensities ≫ 75 kV/m. This study investigated the generality of this behavior by studying the response of rats when exposed to high voltage direct current (HV dc) electric fields. Three hundred eighty male Long Evans rats were studied in 9 experiments with 40 rats per experiment and in one experiment with 20 rats to determine 1) if rats avoid exposure to HVdc electric fields of varying field strengths, and 2) if avoidance did occur, what role, if any, the concentration of air ions would have on the avoidance behavior. In all experiments a three‐compartment glass shuttlebox was used; either the left or right compartment could be exposed to a combination of HVdc electric fields and air ions while the other compartment remained sham‐exposed. The third, center compartment was a transition zone between exposure and sham‐exposure. In each experiment, the rats were individually assessed in 1‐h sessions where half of the rats (n = 20) had the choice to locomote between the two sides being exposed or sham‐exposed, while the other half of the rats'(n = 20) were sham‐exposed regardless of their location, except in one experiment where there was no sham‐exposed group. The exposure levels for the first six experiments were 80, 55, 42.5, 30, −36, and −55 kV/m, respectively. The air ion concentration was constant at 1.4 × 106 ions/cc for the four positive exposure levels and −1.4 × 106 ions/cc for the two negative exposure levels. Rats having a choice between exposure and non‐exposure relative to always sham‐exposed control animals significantly reduced the amount of time spent on the exposed side at 80kV/m (P < .002) as they did at both 55 and −55 kV/m (P < .005). No significant differences between groups were observed at 42.5, 30, or ‐36 kV/m. To determine what role the air ion concentration might have had on the avoidance behavior at field strengths of 55 kV/m or greater, four additional experiments were conducted. The HVdc exposure level was held constant at either −55 kV/m (for three experiments) or ‐55 kV/m (for 1 experiment) while the air ion concentration was varied between experiments at 2.5 × 105 ions/cc, 1.0 × 104 for two of the experiments and was below the measurement limit (< ± 2 × 103 ions/cc) for the other two experiments at 55 and −55 kV/m.

The exposed rats significantly reduced the amount of time spent on the exposed side at 55 and −55 kV/m, relative to the sham‐exposed rats regardless of air ion concentration (all at P < .005). Thus, HVdc electric fields of ≫ + or −55 kV/m are sufficient to produce avoidance behavior in rats. Positive or negative air ion concentrations were not significant factors in these avoidance outcomes. © 1993 Wiley‐Liss, Inc.
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

The 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

A 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

Cytogenetic 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

The 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

The 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.