bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modification of the repeated acquisition of response sequences in rats by low‐level microwave exposure
Authors: Schrot John , Thomas John R. , Banvard Richard A. 
Published: February 2006

AbstractThe acute effects of microwave exposure on a repeated acquisition baseline were investigated in three rats. Each session the animals acquired a different four‐member response sequence. Each of the first three correct responses advanced the sequence to the next member, and the fourth correct response produced food reinforcement. Incorrect responses produced a three‐second timeout. Baseline and control sessions were characterized by a decrease in errors within each session. The animals were acutely exposed to a 2.8 GHz pulsed‐microwave field prior to test sessions, with average power densities ranging from 0.25 to 10 mW/cm2. In comparison to control sessions, 1/2 hour of exposure to microwave radiation at power densities of 5 and 10 mW/cm2 increased errors and altered the pattern of within‐session acquisition. Exposure to the 10 mW/cm2 power density decreased the rate of sequence completion in all animals. The results of exposures at 0.25, 0.5, and 1 mW/cm2 power densities were generally within the control range. The results are interpreted as indicating a disruption in the discriminative stimulus control of the repeated acquisition behavior.
Comparison of the coupling of grounded humans, swine and rats to vertical, 60‐Hz electric fields
Authors: Kaune W. T. , Phillips R. D. 
Published: February 2006

AbstractPublished and new data for grounded humans, swine, and rats exposed to vertical, 60‐Hz electric fields are used to determine field strengths at the surfaces of the bodies and average components of induced‐current density along the axes of the bodies. At the tops of the bodies, surface electric fields are increased (enhanced) over the unperturbed field strength present before the subjects entered the field by factors of 17,7, and 4 for humans, swine, and rats, respectively. For an unperturbed field strength of 10 kV/m, average induced axial current densities in the neck, chest, abdomen, and feet are: 550, 190, 250, and 2000 nA/cm2, respectively, for humans; 40, 13, 20, and 1100 nA/cm2, respectively, for swine; and 28, 16, 2, and 1400 nA/cm2, respectively, for rats. These data are used to show that the actual electric fields experienced by animals depend strongly on the shape of the body and its orientation relative to the electric field and ground plane. This fact must be taken into account if biological data obtained with laboratory animals are to be used for the assessment of possible hazards to humans exposed to 60‐Hz electric fields.
Effect of microwaves (2450‐MHz) on the immune system in mice: Studies of nucleic acid and protein synthesis
Authors: Wiktor‐Jedrzejczak W. , Ahmed A. , Czerski P. , Leach W. M. , Sell K. W. 
Published: February 2006

AbstractCBA/J adult male mice were given single or triple exposures to 2450‐MHz microwaves in an environmentally controlled wave guide facility. The average absorbed dose rate for a single exposure varied from 12 to 15 mW/g. Shamexposed mice served as controls. Lymphoid cells were collected and tested for metabolic activity on days 3, 6, and 9 following a single exposure, and on days 9, 12, and 16 following triple exposures on days 0, 3, and 6. Cells were cultured in vitro for four hours to seven days before their metabolic rates were assayed. Under these conditions, microwaves failed to produce any detectable change in deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein synthesis, as measured by the incorporation of methyl(3H)‐thymidine (3H‐TDR) (DNA substrate), 3H‐uridine (3H‐UR) (RNA substrate), and 3H‐leucine (protein substrate) by spleen, bone marrow, and peripheral blood lymphocytes (PBL) in vitro. These data suggest that microwave‐induced increases in the frequency of complement‐receptor (CR)‐ or surface‐immunoglobulin (sIg)‐bearing cells were not associated with a concomitant increase in cell proliferation and/or protein synthesis, and favor the concept that microwaves under these conditions stimulate already existing B‐cell precursors for maturation.
Microwave effects on energy metabolism of rat brain
Authors: Sanders Aaron P. , Schaefer Daniel J. , Joines William T. 
Published: February 2006

AbstractRat brain was exposed to 591‐MHz, continuous‐wave (CW) microwaves at 13.8 or 5.0 mW/cm2 to determine the effect on nicotinamide adenine dinucleotide, reduced (NADH), adenosine triphosphate (ATP) and creatine phosphate (CP) levels. On initiation of the in vivo microwave exposures, fluorimetrically determined NADH rapidly increased to a maximum of 4.0%–12.5% above pre‐exposure control levels at one‐half minute, then decreased slowly to 2% above control at three minutes, finally increasing slowly to 5% above control level at five minutes. ATP and CP assays were performed on sham‐ and microwave‐exposed brain at each exposure time. At 13.8 mW/cm2, brain CP level was decreased an average of 39.4%, 41.1%, 18.2%, 13.1%, and 36.4% of control at exposure points one‐half, one, two three, and five minutes, respectively, and brain ATP concentration was decreased an average of 25.2%, 15.2%, 17.8%, 7.4%, and 11.2% of control at the corresponding exposure periods. ATP and CP levels of rat brain exposed to 591‐MHz cw microwaves at 5 mW/cm2 for one‐half and one minute were decreased significantly below control levels at these exposure times, but were not significantly different from the 13.8 mW/cm2 exposures. For all exposures, rectal temperature remained constant. Heat loss through the skull aperture caused brain temperature to decrease during the five‐minute exposures. This decrease was the same in magnitude for experimental and control subjects. Changes in NADH, ATP, and CP levels during microwave exposure cannot be attributed to general tissue hyperthermia. The data support the hypothesis that microwave exposure inhibits mitochondrial electron transport chain function, which results in decreased ATP and CP levels in brain.
Effects of 60‐Hz electric fields on avoidance behavior and activity of rats
Authors: Hjeresen Dennis L. , Kaune William T. , Decker John R. , Phillips Richard D. 
Published: February 2006

AbstractIn repeated short‐term tests (four sessions, each of 45‐minute duration), and one longer test (a 23.5‐hour session), behavior of rats was evaluated in a long, narrow shuttlebox. One side of the box was exposed to an electric field at various strengths, while a visually identical opposite side was shielded from exposure. In the short‐term tests, rats generally remained shielded from electric fields of 90 kV/m and greater during the first session, and maintained this response in subsequent sessions. In the longer test, this same preference response was demonstrated at field strengths of 75 kV/m and greater; however, at 25 and 50 kV/m, rats exhibited a statistically significant preference for the exposed region of the shuttlebox, but only during the light portion of a 12‐hour light: 12‐hour dark cycle. Exposed animals made more traverses than sham‐exposed controls between the two ends of the shuttlebox during the first hour of the test. The experimental data support the hypothesis that the observed behavioral effects are the result of direct interaction of the electric field with the animal, and not the result of secondary factors such as electric shock, corona discharge, audible noise, ozone, or vibration of the experimental apparatus.
Studies on microwave and blood‐brain barrier interaction
Authors: Lin James C. , Lin Mei F. 
Published: February 2006

AbstractThis investigation was aimed at correlating changes of blood‐brain‐barrier permeability with the quantity and distribution of absorbed microwave energy inside the brain of adult Wistar rats anesthetized by sodium pentobarbital. Through use of thermographic methods and a direct‐contact applicator at the animal's head, the pattern of absorbed microwave energy was determined. Indwelling catheters were placed in the femoral vein and in the left external carotid artery. Evans blue and sodium fluorescein in isotonic saline were used as visual indicators of barrier permeation. Exposure to pulsed 2,450‐MHz radiation for 20 min at average power densities of 0.5, 1, 5, 20, 145 or 1,000 mW/cm2, which resulted in average specific absorption rates (SARs) of 0.04, 0.08, 0.4, 1.6, 11.5 or 80.0 mW/g in the brain, did not produce staining, except in the pineal body, the pituitary gland, and the choroid plexus — regions that normally are highly permeable. Except for these regions, staining was also absent in the brains of sham‐exposed animals. The rectal temperature, as monitored by a copper‐constantan thermocouple, showed a maximum increase of less than 0.75°C from a mean pre‐exposure temperature of 36.6°C. The highest brain temperature recorded in a similar group of animals using a thickfilm carbon thermistor was less than 41.0°C.
Dosimetry for a study of effects of 2.45‐GHz microwaves on mouse testis
Authors: Cairnie A. B. , Hill D. A. , Assenheim H. M. 
Published: February 2006

AbstractIn order to determine the effects of microwave radiation on the testis, it is necessary to express the physical insult in animal studies in a way that can be replicated elsewhere and ultimately used as a basis for extrapolation to man. However, there is conflict — especially in chronic experiments — between the desire for precise dosimetry and the need to minimise alteration of the normal physiological functions of the animals. The compromise arrangement used in this study was to house the mice singly, in cages with limited food and water, and to irradiate them for up to 30 days (16 h/day) in an anechoic chamber. The only measurements taken routinely were of power density in the positions normally occupied by the cages. In addition, a series of absorption measurements was made in mouse carcasses: Whole‐body specific absorption rate (SAR); energy‐deposition patterns (determined thermographically); and local SAR in testis (using a miniature electric (E)‐field probe). It was concluded that the SAR in testis was considerably less than the whole‐body SAR. Exposure for 16 h at 50 mW/cm2 elevated rectal but not testis temperature, thus demonstrating the ability of the conscious mouse to regulate the temperature of its testis.
A computer model of temperature distribution inside a lossy sphere after microwave radiation
Authors: Janna W. S. , Russo E. P. , McAfee R. , Davoudi Reza M. 
Published: February 2006

AbstractThe temperature distribution inside a lossy sphere resulting from the absorption of microwave energy was approximated by successive numerical iterations, of the thermal energy equation. Heat transfer within the sphere by conduction was considered. In the model energy was not dissipated by convection but was contained in the sphere for over 200 seconds. Exposure of a 5‐cm sphere to 3,000 MHz at 30 mW/cm2 for 200 seconds was calculated to produce a temperature rise of 0.56°C near the front surface.
Microwave radiation (2450 MHz) alters the endotoxin‐induced hypothermic response of rats
Authors: Smialowicz R. J. , Compton K. L. , Riddle M. M. , Rogers R. R. , Brugnolotti P. L. 
Published: February 2006

AbstractThe parenteral administration of bacterial endotoxin to rats causes a hypothermia that is maximal after approximately 90 minutes. When endotoxin‐injected rats were held in a controlled environment at 22°C and 50% relative humidity and exposed for 90 minutes to microwaves (2450 MHz, CW) at 1 mW/cm2, significant increases were observed in body temperature compared with endotoxintreated, sham‐irradiated rats. The magnitude of the response was related to power density (10 mW/cm2 > 5 mW/cm2 > 1 mW/cm2). Saline‐injected rats exposed for 90 minutes at 5 mW/cm2 (specific absorption rate approximately 1.0 mW/g) showed no significant increase in body temperature compared with saline‐injected, sham‐irradiated rats. The hypothermia induced by endotoxin in rats was also found to be affected by ambient temperature alone. Increases in ambient temperature above 22°C in the absence of microwaves caused a concomitant increase in body temperature. This study reveals that subtle microwave heating is detectable in endotoxin‐treated rats that have an impaired thermoregulatory capability. These results indicate that the interpretation of microwave‐induced biological effects observed in animals at comparable rates and levels of energy absorption should include a consideration of the thermogenic potential of microwaves.
Plane‐wave spectrum approach for the calculation of electromagnetic absorption under near‐field exposure conditions
Authors: Chatterjee I. , Gandhi O. P. , Hagmann M. J. , Riazi A. 
Published: February 2006

AbstractThe exposure of humans to electromagnetic near fields has not been sufficiently emphasized by researchers. We have used the plane‐wave‐spectrum approach to evaluate the electromagnetic field and determine the energy deposited in a lossy, homogeneous, semi‐infinite slab placed in the near field of a source leaking radiation. Values of the fields and absorbed energy in the target are obtained by vector summation of the contributions of all the plane waves into which the prescribed field is decomposed. Use of a fast Fourier transform algorithm contributes to the high efficiency of the computations. The numerical results show that, for field distributions that are nearly constant over a physical extent of at least a free‐space wavelength, the energy coupled into the target is approximately equal to that resulting from plane‐wave exposure.
Electromagnetic absorption in a multilayered slab model of tissue under near‐field exposure conditions
Authors: Chatterjee I. , Hagmann M. J. , Gandhi O. P. 
Published: February 2006

AbstractThe electromagnetic energy deposited in a semi‐infinite slab model consisting of skin, fat, and muscle layers is calculated for both plane‐wave and near‐field exposures. The plane‐wave spectrum (PWS) approach is used to calculate the energy deposited in the model by fields present due to leakage from equipment using electromagnetic energy. This analysis applies to near‐field exposures where coupling of the target to the leakage source can be neglected. Calculations were made for 2,450 MHz, at which frequency the layered slab adequately models flat regions of the human body. Resonant absorption due to layering is examined as a function of the skin and fat thicknesses for plane‐wave exposure and as a function of the physical extent of the near‐field distribution. Calculations show that for fields that are nearly constant over at least a free‐space wavelength, the energy deposition (for the skin, fat, and muscle combination that gives resonant absorption) is equal to or less than that resulting from plane‐wave exposure, but is appreciably greater than that obtained for a homogeneous muscle slab model.
Alteration of circulating antibody response of mice exposed to 9‐GHz pulsed microwaves
Authors: Liddle C. G. , Putnam J. P. , Ali J. S. , Lewis J. Y. , Bell B. , West M. W. , Lewter O. H. 
Published: February 2006

AbstractA significant increase was observed in the circulating antibody titers of mice exposed to 9‐GHz pulsed microwaves at an average power density of 10 mW/ cm2, two hours per day for five days compared with sham‐irradiated animals. The mice were previously immunized with type III pneumococcal polysaccharide. Following irradiation, a portion of the immunized animals were challenged with virulent Streptococcus pneumoniae, type III. Ten days after challenge, mortality was essentially the same in the two groups, but during the ten day period, there was a noticeable increase in the survival time of the irradiated animals compared with the sham‐irradiated animals, suggesting that the increased circulating antibody response afforded some degree of temporary protection to the animals.
Microwave irradiation and instrumental behavior in rats: Unitized irradiation and behavioral evaluation facility
Authors: Lebovitz R. M. , Seaman R. L. 
Published: February 2006

AbstractA facility for the exposure of small animals to pulse‐modulated microwave radiation (PM MWR) concurrent with their performance of operant behavioral tasks is described. The computer‐managed facility comprises an array of 32 individual waveguide exposure cells, each enclosing instrumental conditioning apparatus within a plastic subhousing. The distribution of the microwave electric field intensity within the waveguide was measured by a nonperturbing probe and the modifications induced by the behavioral apparatus and animal within the waveguide determined. Input and interior voltage standing wave ratios are presented to characterize the design of the chambers and to demonstrate the suitability of the chambers for whole‐body irradiation of rat. The specific absorption rate (SAR) is presented utilizing data derived from incremental thermometric examination of saline loads and of selected sites in rat carcasses. This is compared with the whole‐body SAR derived from the input/ output energy balance equation for the waveguide. The results of continuous monitoring of the SAR by the latter method, while unrestrained rats were engaged in operant and exploratory behavior within the waveguide, are utilized to derive a relationship between chamber input power and the dose rate for adult rats behaviorally active within the waveguide. From these data, we conclude that the experimental array provides a practical method for exposing a large number of animals to PM MWR for long periods of time and coincident with the establishment and/or performance of complex operant behavior.
Fluorescence depolarization studies of red cell membrane fluidity. The effect of exposure to 1.0‐GHz microwave radiation
Authors: Allis John W. , Sinha Barbara L. 
Published: February 2006

AbstractThe internal viscosity of human red blood cell membranes was investigated during exposure to continuous wave 1.0‐GHz microwave radiation using fluorescence measurements of a lipid seeking molecular probe, diphenylhexatriene. Samples were exposed in a Crawford cell arranged so that fluorescence was measured during microwave exposure; specific absorption rates calculated from electrical measurements were approximately 0.6, 2 and 15 W/kg. Measurements were obtained at selected temperatures between 15 °C and 40 °C and as a function of the duration of exposure at 23 °C. Arrhenius‐type plots of the temperature profile data were linear and showed no difference between exposed and control samples. The exposure duration data also showed no difference between exposed and control samples except for a small effect of elevated temperature at the highest exposure. The activation energy for motion of the fluorescent probe in its environment within the membrane lipid was not affected by the application of the microwave energy and no evidence for a lipid phase transition was found. These results indicate that the increased cation efflux from red cells, observed by others at certain transition temperatures during microwave exposure, was more likely to have been caused by alteration of the membrane bound protein than by changes in the lipid constituents of the red cell membrane.
Biological effects of oscillating electric fields: Role of voltage‐sensitive ion channels
Authors: Cain Charles A. 
Published: February 2006

AbstractAn alternating component of potential across the membrane of an excitable cell may change the membrane conductance by interacting with the voltagesensing charged groups of the protein macromolecules that form voltage‐sensitive ion channels. Because the probability that a voltage sensor is in a given state is a highly nonlinear function of the applied electric field, the average occupancy of a particular state will change in an oscillating electric field of sufficient magnitude. This “rectification” at the level of the voltage sensors could result in conformational changes (gating) that would modify channel conductance. A simplified two‐state model is examined where the relaxation time of the voltage sensor is assumed to be considerably faster than the fastest changes of ionic conductance. Significant changes in the occupancy of voltage sensor states in response to an applied oscillating electric field are predicted by the model.
Interactive effects in 60‐HZ electric‐field exposure systems
Authors: Kaune William T. 
Published: February 2006

AbstractThe level of exposure of laboratory animals to 60‐Hz electric fields is commonly specified in terms of the unperturbed field strength present before the introduction of experimental subjects and their cages. In the research reported in this paper, rats were housed in two parallel rows of 12.4 cm × 25.1 cm × 10.2 cm high plastic cages resting on the lower electrode of a parallel‐plate exposure system, and the actual perturbed electric fields experienced by an experimental animal were investigated. The most important results are: 1) Reducing the spacing between the exposure electrodes from 8.7 to 1.7 times the height of a singly exposed rat model, while maintaining a constant unperturbed field strength, resulted in a 15% increase in the electric field at the highest point on the surface of the body and a 10% increase in the short‐circuit current of the model. 2) For multiple animal exposures, increases of 10% in both the field at the highest point of the body and the short‐circuit current were observed when the electrode spacing was reduced from 8.7 to 2.6 times the height of a rat. 3) Plastic cages caused 1 – 6% reductions in the electric field at the surface of the body, except very near the cage walls, where enhancements of more than 20% were observed. 4) When 16 rats were simultaneously exposed, the short‐circuit current, Is, of an individual subject of weight W (in g), that was surrounded on all sides by other rats of weight W, was reduced from the short‐circuit current, Iu, measured with the same subject individually exposed as follows: during a 12 h light (sleeping) cycle, Is/Iu = 1.00 – 0.0173W1/2; during a 12 h night (awake) cycle, Is/Iu = 1.00 – 0.0136W1/2.
Radiofrequency electromagnetic fields in swedish radio stations and tall FM/TV towers
Authors: Mild Kjell Hansson 
Published: February 2006

AbstractRadiofrequency electric and magnetic fields have been measured around 11 large broadcast stations and tall FM/TV towers in Sweden. The results show that operating personnel may be exposed to fields exceeding by several times the present standard for occupational exposure to RF radiation. Maintenance personnel are especially vulnerable to exposure when climbing energized towers. The present study indicates that the transmitters should be switched off during the performance of certain tasks on the tower. Safe passage of maintenance personnel near energized antennas of certain types is impossible without a drastic reduction of the transmitted power. In the stations, the RF leakage radiation was generally low, but when work was done with the cabinet doors of the transmitter open, high field strengths were found in the vicinity of the transmitter even though it was switched off. It was found that the transmitter acted as a tuned receiver of energy from the other transmitters.
Microwave treatment of intracerebral l1210 leukemia: Schedule‐dependent partial reversal of the effects of methotrexate
Authors: Chang Barbara K. , Huang Andrew T. , Joines William T. 
Published: February 2006

AbstractOne‐GHz microwave (MW) irradiation at a power density of 5 mW/cm2 was combined with methotrexate (MTX) in an attempt to treat more effectively central nervous system (CNS) L1210 leukemia in DBA/2J mice. When mice with CNS leukemia were treated with the combination of MW and MTX, there was no improvement in survival compared with a group of animals treated with MTX alone; however, the group that received MTX before the MW exposure had a significantly reduced survival time compared with the group treated with MTX alone or with the group to which MTX was administered after MW.