bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperature dependence of ultrasound‐induced cell killing: The role of membrane fluidity
Authors: Ben‐Hur E. , Green M. 
Published: February 2006

AbstractChinese hamster cells in suspension were exposed to 20 kHz ultrasound (US) at 54 W/cm2 and various temperatures between 2 and 44 °C. Activation energies were 2.6 and 24 kcal/mole below and above 35 °C, respectively. Procaine, a local anaesthetic drug known to increase membrane fluidity, enhanced cellular inactivation by US above 41 °C, increasing the activation energy to 62 kcal/mole. The inactivation of the bacterium Salmonella typhimurium by US was also dependent on the exposure temperature, with an activation energy of 2.9 kcal/mole between 2 and 44 °C. These data are most simply explained by the hypothesis that membranes are a major target for cellular inactivation by US and that the fluidity of the membranes is important in this respect.
Reduced weight in mice offspring after in utero exposure to 2450‐MHz (CW) microwaves
Authors: Berman Ezra , Carter Hershell B. , House Dennis 
Published: February 2006

AbstractTime‐bred CD‐1 mice (100) were sham‐irradiated or irradiated with 2450‐MHz (CW) microwaves at 28 mW/cm2 for 100 minutes daily from the 6th through 17th day of gestation. The offspring were examined either as fetuses after hysterotomy on the 18th day of gestation or as naturally born neonates on the 1st and 7th day of age. Fetuses of half of the dams were examined on the 18th day of gestation. The incidence of pregnancy and the numbers of live, dead, resorbed, and total fetuses were similar in both groups. The mean weight was significantly lower (10%) in live microwave‐irradiated fetuses, and ossification of sternal centers was significantly delayed. In the offspring that were born naturally, the mean weight of microwave‐irradiated 7‐day‐old suckling mice was significantly lower (10%) than that of the sham‐irradiated group. Survival rates of neonates in these two groups were not different. These data demonstrate that the decreased fetal weight seen in microwave‐irradiated mice is retained at least 7 days after birth. Evidence from other published studies is presented to show that the retarded growth is persistent and might be interpreted as permanent stunting.
Low frequency amplitude modulated microwave fields change calcium efflux rates from synaptosomes
Authors: Lin‐Liu S. , Adey W. R. 
Published: February 2006

AbstractCalcium(45Ca2 +) efflux from preloaded synaptosomes was studied with a continuous perfusion technique and the rate constants of a two‐phase efflux process calculated. When 16‐Hz sinusoidally amplitude modulated 450‐MHz microwave field (maximal incident intensity 0.5 mW/ cm2, modulation depth 75%) was applied during the second phase, the rate constant increased by 38%. Unmodulated or 60‐Hz modulated signals were not effective. This microwave fieldinduced change can be distinguished from CaCl2‐stimulated 45Ca2 + efflux which is most probably derived intracellularly. These data suggest that the microwave‐field‐induced change in calcium efflux probably did not involve intracellular calcium. Also, this change in the dynamic property of synaptosomes did not require gross anatomically intact tissue as a substrate for field tissue interaction.
Fluorescence depolarization studies of the phase transition in multilamellar phospholipid vesicles exposed to 1.0‐GHz microwave radiation
Authors: Allis John W. , Sinha Barbara L. 
Published: February 2006

AbstractThe phase transition in multilamellar dimyristoylphosphatidylcholine (DMPC) vesicles was studied during exposure to continuous wave 1.0‐GHz microwave radiation. Fluorescence depolarization measurements using a lipid‐seeking molecular probe, diphenylhexatriene (DPH). were performed as a function of temperature. Semilog plots of microviscosity versus temperature illustrate the phase transition which shows a 5°C shift when the vesicles are treated with chloroform as a positive control. No shift of the phase transition was found during exposure to microwave radiation at specific absorption rates between 1 and 30 W/kg. Samples were exposed in a rectangular transmission line (TEM cell), and specific absorption rates were calculated from electrical measurements of incident, reflected, and transmitted power. Samples were exposed to increasing intensities of radiation, while the temperature was maintained at either 23.5 or 25.5 °C; these temperatures represented the two ends of the phase transition region for these vesicles. No statistically significant difference was found between exposed and control samples. These results are in contrast to those of others using laser Raman spectroscopy to measure the phase transition in similar multilamellar vesicles exposed to microwave radiation.
Effects of 60‐Hz electric fields on specific humoral and cellular components of the immune system
Authors: Morris J. E. , Phillips R. D. 
Published: February 2006

AbstractWe evaluated humoral and cellular functions of the immune system of Swiss‐Webster mice exposed to 60‐Hz electric fields at 100 kV/m. No significant differences were observed in primary antibody response to keyhole limpet hemocyanin (precipitating antibody levels) between exposed (30 or 60 days) and control mice, nor were there significant changes in mitogen‐stimulation response of spleen cells from mice similarly exposed for 90 or 150 days when compared to sham‐exposed animals.
Possible effects of 1011 Hz radiation on the oxygen affinity of hemoglobin
Authors: Kondepudi D. K. 
Published: February 2006

AbstractWhen oxygen binds to one of the subunits of hemoglobin, the oxygen affinity of the other subunits is enhanced. This cooperative interaction of the subunits is initiated by the movement of the heme plane toward the proximal side when oxygen binds to the heme. This motion is transmitted to the surface of the globin through a “reaction channel” consisting of a group of atoms whose motion is well correlated. Considering the detailed geometry and X‐ray diffraction data of the mean square displacement of the atoms surrounding the heme, a simple model for the heme plane oscillations is developed. Using this model, the natural frequency of oscillations is shown to be ≈5 × 1011 Hz. This result, along with the recent experimental data on the kinetics of the conformational changes of the heme, points to the possibility of radiation influencing the oxygen affinity of hemoglobin. If such an effect exists, it is likely that the oxygen affinity will be enhanced by the radiation.
Local tumor hyperthermia using a computer‐controlled microwave system
Authors: Magin R. L. , Fu T. S. , Beard R. E. , Cain C. A. 
Published: February 2006

AbstractA minicomputer‐based system was designed to control the microwave (2.45‐GHz) power to four local hyperthermia applicators. Errors in temperature measurement, due to electromagnetic field interactions with small thermocouple probes, are minimized by sampling the temperature only when the microwave power is off. The programmable controller can regulate the temperature in tumors in 0.1 °C increments from 30 to 60 °C. This technique reduces temperature differences throughout the tumor at steady state to less than 0.4 °C and prevents skin burns.
Systems for exposing mice to 2,450‐MHz electromagnetic fields
Authors: Chou Chung‐Kwang , Guy Arthur W. 
Published: February 2006

AbstractTwo systems for exposing mice to 2,450‐MHz electromagnetic fields are described. In a waveguide system, four mice were placed in a Styrofoam cage and exposed dorsally to circularly polarized electromagnetic fields. The temperature and humidity in the mouse holder were kept constant by forced‐air ventilation. For 1‐W input power to the waveguide, the average specific absorption rate (SAR) was determined by twin‐well calorimetry to be 3.60 ± 0.11 (SE) W/kg in 27‐g mice. The maximum SAR at the skin surface determined thermographically was 8.36 W/kg in the head of the mouse. The second system was a miniature anechoic chamber. Six mice were irradiated dorsally to far field plane waves. Copper shielding and high‐temperature absorbing material were lined inside the chamber to accommodate the high input power. The air ventilation at the location of the mice was separately controlled so that any heating in the absorber would not affect the animals. For 1‐W input power, the average SAR was 0.17 ± 0.01 W/kg and the maximum SAR at the skin surface was 0.41 W/kg in the animal when irradiated with body axis parallel to the E field; the SARs were 0.11 ± 0.01 W/kg and 0.64 W/kg, respectively, when irradiated perpendicular to the E field.
In vivo and in vitro dielectric properties of animal tissues at radio frequencies
Authors: Kraszewski Andrzej , Stuchly Maria A. , Stuchly Stanislaw S. , Smith Andrew M. 
Published: February 2006

AbstractAn open‐ended coaxial line and an improved measurement method employing a computer controlled network analyzer were used to measure the permittivity of cat tissues. Muscle, spleen, kidney cortex, liver,and brain cortex were measured in vivo and in vitro at frequencies between 100 MHz and 8 GHz. The differences between the permittivities of these cat tissues, in the aforementioned range of frequencies, when measured in vivo and a few (up to four) hours after death, were found to be within the experimental uncertainty.
A behavioral response of swine to a 60‐Hz electric field
Authors: Hjeresen D. L. , Miller M. C. , Kaune W. T. , Phillips R. D. 
Published: February 2006

AbstractIt has been shown that rats, given the choice, will spend more time out of a 60‐Hz electric field than in it at field strengths ⩾ 75 kV/m. This paper describes research to examine the relevance of these data to a different species, the pig. Miniature pigs that had been exposed to a 60‐Hz electric field at 30 kV/m for 20 h/day, 7 days/week for as long as 6 months, were tested for their preference for the presence or absence of the field during a 23.5‐h period. Similar to earlier results with rats, miniature pigs spent more time out of the electric field than in it during the sleeping period.
Effects of X‐band microwave exposure on rabbit erythrocytes
Authors: Cleary S. F. , Garber F. , Liu L. M. 
Published: February 2006

AbstractRabbit erythrocytes were exposed in vitro to continuous wave (CW) and pulse‐modulated X‐band microwaves in wave guide exposure chambers. Erythrocytes were exposed as whole (hep‐arinized) blood suspensions or as washed cells in 1:1 isotonic buffered K+‐free saline suspensions. Statistically significant increases in K+ efflux relative to thermal controls were detected when red cells were exposed in whole blood suspensions to either CW or pulsed 8.42‐GHz microwaves at SARs that resulted in equilibrium sample temperatures of approximately 24 °C. Under the same exposure conditions, no statistically significant K+ efflux occurred in the case of 1:1 red cell suspensions. Measured differences in sample heating rates and temperature gradients between microwave‐exposed and heated control suspensions may account in part for the differential effect of microwave exposure but such effects do not appear to explain the results of this study fully.
Attempts to alter 45Ca2+ binding to brain tissue with pulse‐modulated microwave energy
Authors: Merritt James H. , Chamness Albert F. , Shelton Wesley W. 
Published: February 2006

AbstractRat brain tissue, loaded with 45Ca2+ by intraventricular injection was exposed in vitro to pulsemodulated 1‐GHz (SAR of 0.29 or 2.9 W/kg) or 2.45‐GHz radiation (SAR = 0.3 W/kg), and in vivo to 2.06‐GHz radiation (SAR of 0.12 to 2.4 W/kg). There were no significant differences in efflux of 45Ca2+ between the microwave‐ and sham‐irradiated groups.
Minimal changes in hypothalamic temperature accompany microwave‐induced alteration of thermoregulatory behavior
Authors: Adair Eleanor R. , Adams Barbara W. , Akel Gillian M. 
Published: February 2006

AbstractThis study probed the mechanisms underlying microwave‐induced alterations of thermoregulatory behavior. Adult male squirrel monkeys (Saimiri sciureus), trained to regulate the temperature of their immediate environment (Ta) behaviorally, were chronically implanted with Teflon reentrant tubes in the medical preoptic/anterior hypothalamic area (PO/AH), the brainstem region considered to control normal thermoregulatory processes. A Vitek temperature probe inserted into the tube measured PO/AH temperature continuously while changes in thermoregulatory behavior were induced by either brief (10‐min) or prolonged (2.5‐h) unilateral exposures to planewave 2,450‐MHz continuous wave (CW) microwaves (E polarization). Power densities explored ranged from 4 to 20 mW/cm2 (rate of energy absorption [SAR] = 0.05 [W/kg]/[mW/cm2]). Rectal temperature and four representative skin temperatures were also monitored, as was the Ta selected by the animal. When the power density was high enough to induce a monkey to select a cooler Ta (8 mW/cm2 and above), PO/AH temperature rose ∼ 0.3°C but seldom more. Lower power densities usually produced smaller increases in PO/AH temperature and no reliable change in thermoregulatory behavior. Rectal temperature remained constant while PO/AH temperature rose only 0.2–0.3°C during 2.5‐h exposures at 20 mW/cm2 because the Ta selected was 2–3°C cooler than normally preferred. Sometimes PO/AH temperature increments greater than 0.3°C were recorded, but they always accompanied inadequate thermoregulatory behavior. Thus, a PO/AH temperature rise of 0.2–0.3°C, accompanying microwave exposure, appears to be necessary and sufficient to alter thermoregulatory behavior, which ensures in turn that no greater temperature excursions occur in this hypothalamic thermoregulatory center.
Offset of the vacuolar potential of Characean cells in response to electromagnetic radiation over the range 250 Hz‐250 kHz
Authors: Montaigne Kathleen , Pickard William F. 
Published: February 2006

AbstractMeasurements were made of the small, transient offsets of vacuolar potential produced in single cells of Nitella flexilis and Chara braunii by isolated bursts of audio frequency electromagnetic radiation. The offsets increased in magnitude with decreasing frequency of the electromagnetic radiation and, below about 6 kHz, seemed to approach a lowfrequency asymptote. This frequency dependence for the offset is shown to be in accordance with a previously developed model in which the incident radiation is weakly rectified by the cell's membrane system.
In vitro effects of microwave radiation on rat liver mitochondria
Authors: Dutton M. Susan , Galvin Michael J. , McRee D. I. 
Published: February 2006

AbstractLiver mitochondria were exposed in vitro at 30°C to microwave radiation (2.45 GHz) during the following states of respiraton: resting, state 1; substrate dependent, state 2; ADP stimulated, state 3; and ADP depleted, state 4. At 10 or 100 mW/g, with succinate as substrate, no effect of exposure was observed on states 1–4 or the respiratory control index (state 3/state 4) of either tightly or loosely coupled mitochondria. When glutamate was used as substrate, no effects were observed at 10 mW/g. However, in the loosely coupled mitochondria the 100 mW/g exposure produced an increase in states 2 and 4 and a decrease in the respiratory control index. The results suggest that the function of loosely coupled mitochondria can be affected at high power levels of microwave radiation.
Theoretical and experimental determination of SAR patterns for spherical tissue models in a rectangular resonant cavity
Authors: Yang Gen‐Yuan , Chou Chung‐Kwang , Guy Arthur W. 
Published: February 2006

AbstractSpecific absorption rates (SARs) were determined theoretically and experimentally for several spherical models of tissue exposed to electrical fields of TE101 mode in a rectangular cavity of 57.3 MHz resonant frequency. The approximate theoretical SAR can be calculated according to the Mie theory by superposition of four plane waves representing the fields excited in the cavity. The theoretical and thermographically determined SAR patterns in spheres with radii of 5, 7.5, and 10 cm and with conductivities of 0.1, 1, and 10 S/m were compared. For a sphere with radius less than 7.5 cm and conductivity less than 1 S/m, the SAR was quite uniform. When conductivity was increased to 10 S/m, the SAR patterns showed higher absorption in the periphery of the largest sphere (10‐cm radius). These characteristics are important in evaluating the scaling technique of exposing a model of a human to very‐high‐frequency fields to obtain power absorption data in humans exposed to high‐frequency or very‐low‐frequency fields.
The effect of frequency and grounding on whole‐body absorption of humans in E‐polarized radiofrequency fields
Authors: Hill Douglas A. 
Published: February 2006

AbstractThe radiofrequency absorption rates of five male human volunteers have been measured from 3 to 41 MHz. The subjects were exposed at about 10 μW/cm2 inside a very large transverse electromagnetic (TEM) cell and never absorbed more than 1 W. Both the EKH and EHK orientations were employed under both free‐space and grounded conditions. Absorption rates for the EKH orientation exceed those of the EHK orientation by 40% in free space, but only by 6% when grounded. The absorption rates for the grounded men vary with frequency, f, as f1.9 from 3 to 25 MHz and then level off at the peak. The freespace absorption rates vary as f1.7 from 3 to 18 MHz and as f2.9 from 18 to 41 MHz. The average measured absorption rates at 10 MHz exceed the average of the standard model calculations by a factor of three (for free space) or four (grounded). The average man, when exposed grounded in an EKH orientation to the maximum permitted exposure levels under ANSI standard C95.1‐1982, will absorb 0.58 ± 0.14 W/kg over most of the 3 to 41‐MHz frequency range. This slightly exceeds the whole‐body maximum of 0.40 W/kg underlying the standard.
A reference curve for axial bioelectric potentials in rabbit tibia
Authors: Rubinacci A. , Brigatti L. , Tessari L. 
Published: February 2006

AbstractA high coefficient of variation is characteristic of the bioelectric potentials recorded from living long bones. As a consequence, the data collected from animal and human experiments are difficult to use in practical ways. A distribution curve for bone bioelectric potentials has been calculated using polynomial regression analysis to process the voltage values recorded on the whole length of rabbit tibiae, with reference electrodes positioned in three different points of the bone. The distribution curve so obtained is presented to fulfill the need for a reference curve for the bioelectric potentials recorded from rabbit tibial surfaces.
Ethanol‐induced hypothermia and ethanol consumption in the rat are affected by low‐level microwave irradiation
Authors: Lai H. , Horita A. , Chou C. K. , Guy A. W. 
Published: February 2006

AbstractMicrowave irradiation of rats by circularly polarized, 2,450‐MHz, pulsed waves (2‐μs pulses; 500 pps) was performed in waveguides to determine effects on ethanol‐induced hypothermia and on ethanol consumption. Rats injected intraperitoneally with ethanol (3 g/kg in a 25% v/v water solution) immediately after 45 min of microwave irradiation exhibited attenuation of the initial rate of fall in body temperature, which was elicited by the ethanol, but exhibited no significant difference in maximal hypothermia as compared with that of sham‐irradiated rats. Microwave irradiation did not affect the consumption of a 10% sucrose (w/v) solution by water‐deprived rats. However, it enhanced the consumption of a solution of 10% sucrose (w/v) + 15% ethanol (v/v) by water‐deprived animals. These results were obtained at a specific absorption rate (SAR) of 0.6 W/kg, which rate of energy dosing would require a power density of 3–6 mW/cm2 if exposure of the animals had occurred to a 12‐cm plane wave.
Thermal action of 2.45 GHz microwaves on the cytoplasm of Chinese hamster cells
Authors: Dardalhon M. , Moré C. , Averbeck D. , Berteaud A. J. 
Published: February 2006

AbstractIn order to demonstrate possible specific effects of microwaves at the cellular level V‐79 Chinese hamster cells were exposed to 2.45‐GHz radiation at power levels of 20–200 mW/cm2 and at specific absorption rates of 10–100 mW/g. Intracellular cytoplasmic changes were observed by fluorescence polarization using a method based on the intracellular enzymatic hydrolysis of nonfluorescent fluorescein diacetate (FDA). At levels of absorbed energy below 90 J/g, modifications of microviscosity and mitochondrial state were absent, but a slight stimulation of enzymatic hydrolysis of FDA was observed which may be explained by microwave‐induced alterations of cellular membranes possibly due to differences in heating pattern of microwaves compared to water‐bath heating. At levels of absorbed energy above 90 J/g, the decrease of enzymatic hydrolysis of FDA, increase in degree of polarization, and increase of permeation of the fluorescent marker correlated well with the decrease in cell viability as measured by the exclusion of trypan blue. At equal absorbed energy, microwaves were found to exert effects comparable to classical heating except that permeation was slightly more affected by microwave than by classical heating. This suggests that membrane alteration produced by microwaves might differ from those induced by classical heating or that microwaves may have heated the membrane to higher temperatures than did classical heating.
Effect of microwave radiation on the beating rate of isolated frog hearts
Authors: Yee K. C. , Chou C. K. , Guy A. W. 
Published: February 2006

AbstractOne hundred and two isolated frog hearts were divided into ten groups and placed individually in a waveguide filled with Ringer's solution and exposed to 2,450‐MHz CW radiation at 2 and 8.55 W/kg. Heart rate was recorded using one of the following methods: 3‐M KCl glass electrode, ultrasound probe, tension transducer, Ringer's solution glass electrode, and a metal wire inserted in the Ringer's solution electrode. An accelerated decrease of heart rate was observed only in those groups recorded using the 3‐M KCl electrode and the metal wire Ringer's solution electrode. No effect was found in the other groups. These results indicate that bradycardia in isolated hearts could be caused by electrode artifacts resulting from the intensification of electromagnetic fields.
Attempts to produce taste‐aversion learning in rats exposed to 60‐Hz electric fields
Authors: Creim J. A. , Lovely R. H. , Kaune W. T. , Phillips R. D. 
Published: February 2006

AbstractA measure of taste‐aversion (TA) learning was used in three experiments to 1) determine whether exposure to intense 60‐Hz electric fields can produce TA learning in male Sprague‐Dawley rats, and 2) establish a dose‐response function for the behavior in question. In Experiment 1, four groups of eight rats each were distributed into one of two exposures (69 ± 5 kV/m or 133 ± 10 kV/m) or into one of two sham‐exposure groups. Conditioning trials paired 0.1% sodium saccharin in water with 3 h of exposure to a 60‐Hz electric field. Following five conditioning trials, a 20‐min, two‐bottle preference test between water and saccharin‐flavored water failed to reveal TA conditioning in exposed groups. In Experiment 2, four groups of eight rats each (34 ± 2 kV/m or 133 ± 10 kV/m and two sham‐exposed groups) were treated as before. Electric‐field exposure had no effect on TA learning. Experiment 3 tested for a possible synergy between a minimal dose (for TA learning) of cyclophosphamide (6 mg/kg) and 5 h of exposure to 133 ± 10 kV/m electric fields in a dark environment under conditions otherwise similar to those of Experiments 1 and 2. The results indicated no TA learning as reflected in the relative consumption of saccharin.