bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunologic and hematopoietic alterations by 2,450‐MHz electromagnetic radiation
Authors: Huang Andrew Ta‐Fu , Mold Nelda G. 
Published: February 2006

AbstractA biphasic modulation of responsiveness of spleen lymphocytes to mitogens was observed in mice exposed to 2,450‐MHz radiation at power densities of 5–15 mW/cm2 over various periods ranging between one and 17 days. This modulated phenomenon may be explained on the basis of 1) suppression of lymphocyte response by microwave‐activated macrophages which persists throughout the entire course of radiation, and 2) concurrent progressive direct stimulation of lymphocytes which culminates around day 9 of exposure. Tumor cytotoxicity of killer lymphocytes from mice exposed to five or nine days of radiation did not appear different from sham controls. The highly proliferative hematopoietic marrow cells were sensitive to microwave radiation. Nine days of exposure to radiation (15 mW/cm2) reduced the colonyforming units of myeloid and erythroid series by 50%. This observation may offer a new and more sensitive assay for studying biological effects of electromagnetic radiation.
Failure of rats to escape from a potentially lethal microwave field
Authors: Carroll Donna R. , Levinson Daniel M. , Justesen Don R. , Clarke Rex L. 
Published: February 2006

AbstractOcularly pigmented rats, all mature females of the Long‐Evans strain, were repeatedly presented an opportunity to escape from an intense 918‐MHz field (whole‐body dose rate = 60 mW/g) to a field of lower intensity (40, 30, 20, or 2 mW/g) by performing a simple locomotor response. Other rats could escape 800‐μA faradic shock to the feet and tail by performing the same response in the same milieu, a multimode cavity. None of 20 irradiated rats learned to associate entry into a visually well‐demarcated area of the cavity with immediate reduction of dose rate, in spite of field‐induced elevations of body temperature to levels that exceeded 41°C and would have been lethal but for a limit on durations of irradiation. In contrast, all of ten rats motivated by faradic shock rapidly learned to escape. The failure of escape learning by irradiated animals probably arose from deficiencies of motivation and, especially, sensory feedback. Whole‐body hyperthermia induced by a multipath field may lack the painful or directional sensory properties that optimally promote the motive to escape. Moreover, a decline of body temperature after an escape‐response‐contingent reduction of field strength will be relatively slow because of the large thermal time constants of mammalian tissues. Without timely sensory feedback, which is an essential element of negative reinforcement, stimulus‐response associability would be imparied, which could retard or preclude learning of an escape response.
Chronic exposure to a 60‐Hz electric field: Effects on synaptic transmission and peripheral nerve function in the rat
Authors: Jaffe R. A. , Laszewski B. L. , Carr D. B. , Phillips R. D. 
Published: February 2006

AbstractSeveral reports have suggested that the nervous system can be affected by exposure to electric fields and that these effects may have detrimental health consequences for the exposed organism. The purpose of this study was to investigate the effects of chronic (30‐day) exposure of rats to a 60‐Hz, 100‐kV/m electric field on synaptic transmission and peripheral‐nerve function. One hundred forty‐four rats, housed in individual polycarbonate cages were exposed to uniform, vertical, 60‐Hz electric fields in a system free of corona discharge and ozone formation and in which the animals did not receive spark discharges or other shocks during exposure. Following 30 days of exposure to the electric field, superior cervical sympathetic ganglia, vagus and sciatic nerves were removed from rats anesthetized with urethan, placed in a temperature‐controlled chamber, and superfused with a modified mammalian Ringer's solution equilibrated with 95% O2 and 5% CO2. Several measures and tests were used to characterize synaptic transmission and peripheral‐nerve function. These included amplitude, area, and configuration of the postsynaptic or whole‐nerve compound‐action potential; conduction velocity; accommodation; refractory period; strength‐duration curves; conditioning‐test (C‐T) response, frequency response; post‐tetanic response; and high‐frequency‐induced fatigue. The results of a series of neurophysiologic tests and measurements indicate that only synaptic transmission is significantly and consistently affected by chronic (30‐day) exposure to a 60‐Hz, 100‐kV/m electric field. Specifically, an increase in synaptic excitability was detected in replicated measurements of the C‐T response ratio. In addition, there are trends in other data that can be interpreted to suggest a generalized increase in neuronal excitability in exposed animals.
Far‐field microwave dosimetry in a rhesus monkey model
Authors: Olsen Richard G. , Griner Toby A. , Prettyman George D. 
Published: February 2006

AbstractDosimetric measurements were made in a muscle‐equivalent model of an adult rhesus monkey subjected to far‐field irradiation at 1.29 GHz. Profiles of microwave‐induced heating in the model were obtained at eight locations, and a gradient‐layer whole‐body calorimeter was used to measure total absorbed energy. Average specific absorption rate (SAR) was calculated both from the calorimeter experiments and from the local temperature measurements. Thermographic imaging techniques were used to qualitatively show the microwave‐induced surface heating patterns. For this model the calculated average SAR was 0.155 (W/kg)/(mW/cm2) which, at 1.29 GHs, makes the absorption cross section 84% of the geometric shadow cross section. The SAR is about three times that predicted for a prolate spheroidal model of similar mass. A disproportionally high absorption occured in the legs of the model positioned parallel to the E‐polarization because of what is believed to be partial‐body resonance.
A thermal model of the human body exposed to an electromagnetic field
Authors: Spiegel R. J. , Deffenbaugh D. M. , Mann J. E. 
Published: February 2006

AbstractThe human body was modeled by numerical procedures to determine the thermal response under varied electromagnetic (EM) exposures. The basic approach taken was to modify the heat transfer equations for man in air to account for thermal loading due to the energy absorbed from the EM field. The human body was represented in an EM model by a large number of small cubical cells of tissue, and the energy density was determined for each cell. This information was then analyzed by a thermal response model consisting of a series of two‐dimensional transient conduction equations with internal heat generation due to metabolism, internal convective heat transfer due to blood flow, external interaction by convection and radiation, and cooling of the skin by sweating and evaporation. This model simulated the human body by a series of cylindrical segments. The local temperature at 61 discrete locations as well as the thermoregulatory responses of vasodilatation and sweating were computed for a number of EM field intensities and two frequencies, one near whole‐body resonance.
Power density, field intensity, and carrier frequency determinants of RF‐energy‐lnduced calcium‐ion efflux from brain tissue
Authors: Joines William T. , Blackman Carl F. 
Published: February 2006

AbstractTo explain a carrier frequency dependence reported for radiofrequency (RF)‐induced calcium‐ion efflux from brain tissue, a chick‐brain hemisphere bathed in buffer solution is modeled as a sphere within the uniform field of the incident electromagnetic wave. Calculations on a spherical model show that the average electric‐field intensity within the sample remains the same at different carrier frequencies if the incident power density (Pi) is adjusted by an amount that compensates for the change in complex permittivity (ϵ) and the change of wavelength, as a function of carrier frequency. The resulting formula for transforming Pi is seen to follow the pattern of both positive and negative demonstrations of calcium‐ion efflux that have been observed at carrier frequencies of 50, 147, and 450 MHz. Indeed, all results obtained at these three frequencies, when related by Pi's that produce the same average electric‐field intensity within the sample, are seen to be in agreement; no prediction is contradicted by an experiment.
Calcium‐ion efflux from brain tissue: Power‐density versus internal field‐intensity dependencies at 50‐MHz RF radiation
Authors: Blackman C. F. , Benane S. G. , Joines W. T. , Hollis M. A. , House D. E. 
Published: February 2006

AbstractIn previous experiments changes were found in calcium‐ion efflux from chickbrain tissue that had been exposed in vitro to 147‐MHz radiation across a specific range of power densities when the field was amplitude modulated at 16 Hz. In the present study, 50‐MHz radiation, similarly modulated as a sinusoid, was found to produce changes in calcium‐ion efflux from chick brains exposed in vitro in a Crawford cell. Exposure conditions were optimized to broaden any power‐density window and to enhance the opportunity to detect changes in the calcium‐ion efflux. The results of a power‐density series demonstrated two effective ranges: One spanning a range from 1.44 to 1.67 mW/cm2, and the other including 3.64 mW/cm2, which were bracketed by no‐effect results at 0.72, 2.17, and 4.32 mW/cm2. Peaks of positive findings are associated with near‐identical rates of energy absorption: 1.4 μW/g at 147 MHz, and 1.3 μW/g at 50 MHz, which indicates that the enhanced‐efflux phenomenon is more dependent on the intensity of fields in the brain than on the power density of incident radiation. In addition, the phenomenon appears to occur at multiples of some, as yet unknown, rate of radiofrequency (RF) energy absorption. Because of the extremely small increments of temperature associated with positive findings (< 4 × 10−4°C), and the existence of more than one productive absorption rate, a solely thermal explanation appears extremely unlikely.
Millimeter wave absorption spectra of biological samples
Authors: Gandhi O. P. , Hagmann M. J. , Hill D. W. , Partlow L. M. , Bush L. 
Published: February 2006

AbstractA solid‐state computer‐controlled system has been used to make swept‐frequency measurements of absorption of biological specimens from 26.5 to 90.0 GHz. A wide range of samples was used, including solutions of DNA and RNA, and suspensions of BHK‐21/C13 cells, Candida albicans, C krusei, and Escherichia coli. Sharp spectra reported by other workers were not observed. The strong absorbance of water (10–30 dB/mm) caused the absorbance of all aqueous preparations that we examined to have a water‐like dependence on frequency. Reduction of incident power (to below 1.0 μW), elimination of modulation, and control of temperature to assure cell viability were not found to significantly alter the water‐dominated absorbance. Frozen samples of BHK‐21/C13 cells tested at dry ice and liquid nitrogen temperatures were found to have average insertion loss reduced to 0.2 dB/cm but still showed no reproducible peaks that could be attributed to absorption spectra. It is concluded that the spectral resonances reported by others are likely to be in error.
Studies of exposure of rabbits to electromagnetic pulsed fields
Authors: Cleary S. F. , Nickless F. , Liu L. M. , Hoffman R. 
Published: February 2006

AbstractDutch rabbits were acutely exposed to electromagnetic pulsed (EMP) fields (pulse duration 0.4μs, field strengths of 1–2 kV/cm and pulse repetition rates in the range of 10 to 38 Hz) for periods of up to two hours. The dependent variables investigated were pentobarbital‐induced sleeping time and serum chemistry (including serum triglycerides, creatine phosphokinase (CPK) isoenzymes, and sodium and potassium). Core temperature measured immediately pre‐exposure and postexposure revealed no exposure‐related alterations. Over the range of field strengths and pulse durations investigated no consistent, statistically significant alterations were found in the end‐points investigated.
Effects of 2.45‐GHz microwave radiation on embryonic quail hearts
Authors: Galvin M. J. , McRee D. I. , Lieberman M. 
Published: February 2006

AbstractAlthough exposure to nonionizing electromagnetic radiation has been reported to cause a variety of systemic alterations during embryonic development, there are few reports of the induction of specific physiologic or morphologic changes in the myocardium. This study was designed to examine the effects of microwave radiation on cardiogenesis in Japanese quail embryos exposed during the first eight days of development to 2.45‐GHz continuous‐wave microwaves at power densities of 5 or 20 mW/cm2. The specific absorption rates were 4.0 and 16.2 mW/g, respectively. The ambient temperature for each exposure was set to maintain the embryonated eggs at 37.5 °C. This did not preclude thermal gradients in the irradiated embryos since microwaves may not be uniformly absorbed. The test exposure levels did not induce changes in either the morphology of the embryonic heart or the ultrastructure of the myocardial cells. Analysis of the enzymatic activities of lactate dehydrogenase, glutamic oxaloacetic transaminase, and creatine phosphokinase failed to reveal any statistically significant differences between the nonexposed controls and those groups exposed to either 5 or 20 mW/cm2. The data indicate that 2.45‐GHz microwave radiation at 5 or 20 mW/cm2 has no effect on the measured variables of the Japanese quail myocardium exposed during the first eight days of development.
Flight, orientation, and homing abilities of honeybees following exposure to 2.45‐GHz CW microwaves
Authors: Gary Norman E. , Westerdahl Becky Brown 
Published: February 2006

AbstractForaging‐experienced honeybees retained normal flight, orientation, and memory functions after 30 minutes' exposure to 2.45‐GHz CW microwaves at power densities from 3 to 50 mW/cm2. These experiments were conducted at power densities approximating and exceeding those that would be present above receiving antennas of the proposed solar power satellite (SPS) energy transmission system and for a duration exceeding that which honeybees living outside a rectenna might be expected to spend within the rectenna on individual foraging trips. There was no evidence that airborne invertebrates would be significantly affected during transient passage through microwaves associated with SPS ground‐based microwave receiving stations.
Experimental results contradicting claimed 1009‐MHz influence on erythrocyte mobility
Authors: Bamberger S. , Storch F. , Roth G. , Ruhenstroth‐Bauer G. , Keilmann F. 
Published: February 2006

AbstractAn attempt was made to detect the influence of ultrahigh frequency radiation (1009 MHz) on the electrophoretic mobility of human erythrocytes. Ines. In contradiction to an earlier report by Ismailov no effect was observed.
Effects of millimeter‐wave radiation on monolayer cell cultures. II. Scanning and transmission electron microscopy
Authors: Stensaas L. J. , Partlow L. M. , Bush L. G. , Iversen P. L. , Hill D. W. , Hagmann M. J. , Gandhi O. P. 
Published: February 2006

AbstractBoth thermal and athermal effects of millimeter‐wave radiation on BHK‐21/C13 cells were sought using scanning and transmission electron microscopy in conjunction with an in vitro technique that allows direct exposure of monolayer cultures to high average power densities. Culture dishes were irradiated by placing them on the open end of an E‐ or U‐band wave guide. This technique exposes different regions of the cell monolayer lying along the longer axis of the wave guide aperture to varying power densities ranging from zero at each edge to twice the average power density at the center.Cell ultrastructure was unaffected by microwave radiation for 1 hour (41.8 or 74.0 GHz, average power densitites = 320 or 450 mW/cm2, respectively) with or without cooling by rapid recirculation of the culture medium. Temperature in recirculated cultures was held at 37.2 °C, and that in noncooled cultures never exceeded 42 °C during irradiation at either power density. In contrast, cell morphology was affected by microwave exposure whenever irradiation conditions were altered so that the temperature of the monolayer reached or exceeded 44.5 °C. Ultrastructural alterations included breakage of cell processes, progressive detachment of cells from the substrate, increased clumping of heterochromatin in the nuclei, and the appearance of large empty vesicles in the cytoplasm. Such morphological changes resulted from either application of higher average power densities or irradiation at the power densities described above at a higher ambient temperature (>38.5°C).
In vitro microwave effects on human neutrophil precursor cells (CFU‐C)
Authors: Ottenbreit Mark J. , Inoue Susumu , Peterson Ward D. , Lin James C. 
Published: February 2006

AbstractHuman marrow cells were irradiated with 2450‐MHz CW microwaves in a fluid‐filled waveguide irradiation system. Cell exposure was conducted by placing a marrow cell suspension in 20‐μl glass microcapillary tubes that were positioned in the exposure chamber, and irradiated at power densities from 31 to 1,000 mW/cm2 (with corresponding specific absorption rates of 62 to 2,000 mW/g) for 15 minutes. The temperature of the sample was maintained at a fixed point. Sham‐irradiated (SI) and microwave‐irradiated (MWI) cells were cultured in a methylcellulose culture system for neutrophil colony proliferation. There was no reduction in neutrophil colony number on days 6–7 or 12–14 in cells exposed at 31 or 62 mW/cm2, but as the power density was increased to 1,000 mW/cm2, there was a reduction in colony number of MWI cells compared with SI cells. The microwave interaction with the human neutrophil colony‐forming cells was apparently not related to temperature rise, or to the state of cell cycle, and was irreversible.
Transbilayer movement of 24Na in sonicated phosphatidylcholine vesicles exposed to frequency‐modulated microwave radiation
Authors: Fisher Paul D. , Voss W. A. G. , Poznansky Mark J. 
Published: February 2006

AbstractSonicated egg phosphatidylcholine vesicles loaded with 24Na+ were exposed at 20mW to a frequency‐modulated (3 Hz) microwave field in the range of 2350 to 2550 MHz, or at 80 mW to a 2450‐MHz CW (continuous wave) field, in a waveguide. The vesicle suspension absorbed microwaves at about 1 mW/ml and 25 mW/ml (CW experiment). The average temperature change of the irradiated suspension was < 0.1 °C from ambient. Leakage of 24Na+ from the vesicles for up to 19 hours was measured. No difference was noted in the movement of 24Na+ from the vesicles in the irradiated and control dispersions.
Humoral and cell‐mediated immune function in adult japanese quail following exposure to 2.45‐GHz microwave radiation during embryogeny
Authors: Galvin Michael J. , McRee Donald I. , Hall Cynthia A. , Thaxton J. Paul , Parkhurst Carmen R. 
Published: February 2006

AbstractJapanese quail, Coturnix coturnix japonica, eggs were subjected to 2.45‐GHz CW microwave radiation at 5 mW/cm2 (SAR = 4.03 mW/g) during the first 12 days of embryogeny. Following hatching the exposed embryos, as well as nonexposed controls, were reared to 22 weeks of age. Humoral immune potential, as indicated by comparable anti‐CRBC antibody, IgM and IgG, levels at 0, 4, and 7 days postimmunization in both exposed and control quail was not affected significantly. However, cell‐mediated immune potential, measured by the reaction to intradermal injection of phytohemagglutinin‐P in the wing web, was reduced in the exposed females, but not in the exposed males. Additionally, total leukocyte numbers and absolute circulating numbers of lymphocytes, monocytes, and heterophils were increased significantly only in the exposed females. These data show that exposure of Japanese quail during embryogenesis reduced cell‐mediated immune potential and induced a general leukocytosis in females.
Alterations in the rat electrocardiogram induced by stationary magnetic fields
Authors: Gaffey C. T. , Tenforde T. S. 
Published: February 2006

AbstractA field strength dependent increase in the amplitude of the T‐wave signal in the rat electrocardiogram (ECG) was observed during exposure to homogeneous, stationary magnetic fields. For 24 adult Sprague‐Dawley and Buffalo rats of both sexes, the T‐wave amplitude was found to increase by an average of 408% in a 2.0 Tesla (1 Tesla = 104 Gauss) field. No significant magnetically induced changes were observed in other components of the ECG record, including the P wave and the QRS complex. The minimum field level at which augmentation of the T wave could be detected was 0.3 Tesla. The magnetically induced increase in T‐wave amplitude occurred instantaneously, and was immediately reversible after exposure to fields as high as 2.0 Tesla. No abnormalities in any component of the ECG record, including the T wave, were noted during a period of 3 weeks following cessation of a continuous 5‐h exposure of rats to a 1.5‐Tesla field. The heart rate and breathing rate of adult rats were not altered during, or subsequent to, application of fields up to 2.0 Tesla. The effect of animal orientation within the field was tested using juvenile rats 3–14 days old. The maximum increase in T‐wave amplitude was observed when subjects were placed with the long axis of the body perpendicular to the lines of magnetic induction. These experimental observations, as well as theoretical considerations, suggest that augmentation of the signal amplitude in the T‐wave segment of the ECG may result from a superimposed electrical potential generated by aortic blood flow in the presence of a stationary magnetic field.
Comparison of RF‐induced calcium efflux from chick brain tissue at different frequencies: Do the scaled power density windows align?
Authors: Athey T. Whit 
Published: February 2006

AbstractThe recent suggestion that the pattern of positive and negative results of RF‐induced calcium efflux from chick brain tissue, when appropriately scaled, matches at three frequencies is examined. Close scrutiny of this recently reported analysis by Joines and Blackman suggests that the uncertainties in the calculated scaling quantities are too large to permit meaningful conclusions.
Microwave dielectric studies on proteins, tissues, and heterogeneous suspensions
Authors: Foster Kenneth R. , Schepps Jonathan L. , Epstein Benjamin R. 
Published: February 2006

AbstractWe summarize the results of several of our recent studies on the dielectric properties of protein solutions, tissues, and nonionic microemulsions at microwave frequencies extending to 18 GHz. The data in all cases are analyzed using the Maxwell mixture theory to determine the dielectric properties of the suspending water and the amount and dielectric properties of the water of hydration associated with the suspended phase. The dielectric data from the protein solutions and tissues are broadly consistent with the results of previous studies at UHF frequencies; they indicate hydration values in the range of 0.4–0.6 g water/g protein. There is evidence of a dielectric relaxation process occurring at low‐GHz frequencies that can be attributed in part to dielectric relaxation of the “bound” water in the system. The remaining solvent water appears to have dielectric properties close to, if not precisely the same as, those of pure water. The average relaxation frequency of the suspending water in the microemulsions is reduced from that of pure water, evidently reflecting an average of that of the water of hydration (∼5–6 GHz) and that of pure water. This reduced average relaxation frequency implies an increased average viscosity of the water and (by Walden's rule) accounts for the unexpectedly low ionic conductivity of the preparations.