bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractWe 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

AbstractWe 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

AbstractWe 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

AbstractData 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

AbstractThe 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

AbstractRadio‐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

AbstractUsing 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

AbstractA 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

AbstractA 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

AbstractThe 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

AbstractWe 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

AbstractThe 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

AbstractIn 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

AbstractEpidemiologists 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

AbstractNumerical 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

AbstractRats, 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.