bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectroscopic properties of in vivo biological systems: Boson radiative equilibrium with steady‐state nonequilibrium molecular systems
Authors: Illinger K. H. 
Published: February 2006

AbstractAn analysis of the boson (phonon and photon) distribution in the presence of a steady‐state, nonequilibrium molecular subsystem is presented, providing thermodynamic criteria for the boson chemical‐potential term, the generalized vibrational emissivity function, and the Bose type of condensation predicted by Fröhlich.
Photic cuing of escape by rats from an intense microwave field
Authors: Levinson Daniel M. , Grove Anna M. , Clarke Rex L. , Justesen Don R. 
Published: February 2006

AbstractA total of 16 female hooded rats was first observed for baseline behaviors and then they received 25 2‐min trials of training, five trials per day, under one of four stimulus conditions (all ns = 4): exposure to a highly intense 918‐MHz field (dose rate, 60 mW/g); exposure to photic stimulation (≈350 Ix); exposure to the field in synchrony with photic stimulation; or exposure to faradic shock (≈800 μA rms). During conditioning trials, which were separated by 2‐min intertrial intervals, entry by a rat into a safe area of a multimode cavity resulted in immediate and complete cessation of stimulation; exit, in resumption. Acquisition of the escape response was rapid and highly efficient for shocked animals and was less rapid and efficient but was reliably demonstrated by irradiated animals that were also signaled by light. In the absence of microwave irradiation, cessation of light did not reliably motivate escape behavior. Although there was weak evidence of escape learning by rats subjected only to microwave irradiation, their performances failed to differ reliably from those of rats in the light‐only condition. These data confirm and extend those of Carroll et al, which indicate that potentially lethal, deeply penetrating, nonpulsed microwaves in a multipath field lack the sensory quality to motivate efficient aversive behavior by the rat.
The molecular basis of ultrasonic absorption by proteins
Authors: Edmonds P. D. 
Published: February 2006

AbstractThis article reviews significant advances in understanding the basis for the magnitude of ultrasonic absorption in proteins and related biological materials. Carstensen and Schwan's accurate and extensive measurements on blood and hemoglobin solutions provided the initial experimental data; these were augmented by data from measurements on aqueous solutions of gelatin, bovine serum albumin, lysozyme, various polypeptides, and amino acids. The initial frequency range of 1–10 MHz; was expanded to 0.035–1000 MHz; temperature and pH dependences of absorption were studied. Theoretical approaches included consideration of the relative motion of blood cells in plasma, perturbation of water structure around macromolecules, solvation of charged entities, proton‐transfer reactions, and helix‐coil transitions.Proton‐transfer reactions between amino and carboxylic groups and water proved to be largely responsible for the observed peaks in the pH dependence of absorption coefficient; the peaks occurred in the basic and acidic regions corresponding to the pKs for titration of these groups. Such reactions could not account for the magnitude of absorption at physiological pH because only histidine titrated in this range. Extensive analysis, using relaxation theory, and, measurements have shown that the proton transfer reaction between the imidazole group of histidine and hydrogen phosphate ion (in solution) provides sufficient volume change for significant ultrasonic absorption at physiological pH. Excellent agreement between theory and experiment was found with the peptide bacitracin in phosphate buffer solutions. By generalizing these results to the case of a protein, Slutsky et al estimated maximum values of frequency‐dependent absorption coefficients for “typical tissue” and found them to be correct to order of magnitude, even exceeding observed values in soft tissues in some instances, instead of being far too small as was always the case in the past. Thus, in principle, adjustment of parameters, such as pK values, could bring theory and experiment into agreement for the first time.
Effects of electromagnetic radiation in the range 20–300 MHz on the vacuolar potential of characean cells
Authors: Barsoum Yousri H. , Pickard William F. 
Published: February 2006

AbstractA giant cell (circa 10 mm long) of Chara braunii or Nitella flexilis was placed in a microstrip exposure apparatus, and the vacuolar potential at one end was monitored with a micropipette while the other end was exposed to pulses of VHF radiation at electric field strengths up to 6250 V/m. With suitable filtering and signal averaging, offsets of the vacuolar potential could be detected in real time and at levels as low as 1 μU V. The only effect that has been reproducibly observed in the carrier frequency range 20–300 MHz was the slow ramp‐like hyperpolarization previously reported [Pickard and Barsoum, 1981] and tentatively attributed to electromagnetic heating of the system. The slopes of these ramps became more pronounced with increasing frequency and behaved in accordance with theoretical predictions.
Effect of high‐voltage pulses on the viability of human leucocytes in vitro
Authors: Mild K. Hansson , Lövdahl L. , Lövstrand K.‐G. , Løvtrup S. 
Published: February 2006

AbstractHuman leucocytes were exposed to high‐voltage pulses (transient currents) produced by discharging a capacitor through a test chamber containing the cell suspension then tested for viability using trypan blue. With the pulse discharge times of 1 and 3 μs increases in the number of dyeloaded cells were seen for field strengths above 2.6 kV/cm in the sample. For 0.2‐μs pulses the critical field strength was about 5 kV/cm.
Influence of 2.45‐GHz CW microwave radiation on spontaneously beating rat atria
Authors: Galvin M. J. , Dutton M. S. , McRee D. I. 
Published: February 2006

AbstractThe chronotropic and inotropic effects of 2.45‐GHz continuous wave (CW) microwave radiation were investigated in the isolated spontaneously beating rat atria. Isolated atria were placed in specially designed tubes inserted into a waveguide exposure system. The atria were then irradiated for a period of 30 min, followed by a 30‐min recovery period. The control atria were prepared simultaneously and sham exposed. Experiments were conducted at two temperatures, 22 and 37 °C, and two specific absorption rates, 2 mW/g and 10 mW/g. At both temperatures the rate of atrial contraction was not altered by a 30‐min exposure at either 2 or 10 mW/g. The average rate (beats per min) was approximately 100 for both the control and exposed atria at 22 °C and 215 beats per min for both the control and exposed atria at 37 °C. In addition, no inotropic effects on the spontaneously beating atria were noted at any exposure level. These data suggest that 2.45‐GHz CW microwave radiation at these intensities has no overt effect on these variables in isolated rat atria.
Thin‐layer liquid crystal thermometry of cells in vitro during hyperthermal microwave irradiation
Authors: Robinson J. Eugene , McCulloch Duncan , Harrison George H. , Cheung Augustine Y. 
Published: February 2006

AbstractA nonperturbing technique of thin‐layer liquid crystal thermometry was developed to quantitate heating of Chinese hamster ovary cells and the bacterium Serratia marcescens when exposed to 2450‐MHz microwave fields at 0.2–0.5 W/cm2. Cells suspended in culture medium were injected into 5‐cm glass microcapillary tubes coated on the inside with a thin layer of liquid crystal. The tubes were sealed and placed parallel to the electric field in a watertight waveguide exposure chamber where they were heated by circulating temperature‐controlled water. Even at high circulation rates, liquid crystal color changes indicated local microwave capillary tube heating of 0.1–0.25 °C. Precision of measurement was 0.02 °C. Observations during microwave heating were significantly different from observations without microwaves at the 1% level, and heating increased as circulating water flow was reduced from 300 ml/s to 100 ml/s. The results of a cell survival assay following hyperthermal treatment were in good agreement with expectations based on the observations of microwave heating using liquid crystals.
Lack of effect of 2.45‐GHz microwave radiation on the development of preimplantation embryos of mice
Authors: Inouye Minoru , Galvin Michael J. , McRee Donald I. , Matsumoto Nobuo 
Published: February 2006

AbstractThe development of preimplantation embryos after exposure to microwave radiation was studied. Female CD‐1 mice were induced to superovulate, mated, and exposed to 2.45‐GHz microwave or sham radiation for 3 h at power densities of 9 mW/cm2 and 19 mW/cm2 on either day 2 or 3 of pregnancy (plug day was considered day 1). Another group of mice was exposed to heat stress by placing the dams in an environmental room at an ambient temperature of 38 °C and relative humidity at 62% for 3 h on day 2 of pregnancy. All groups were euthanized on day 4 of pregnancy and embryos were recovered by flushing excised uterine horns. Embryos were examined for abnormalities and classified by the developmental stages. They were then treated with hypotonic solution and dissociated for counting blastomeres. Heat stress caused stunted development of embryos, but no remarkable effect of microwave radiation could be found on the development of preimplantation embryos.
Postresonance electromagnetic absorption by man and animals
Authors: Massoudi H. , Durney C. H. , Barber P. W. , Iskander M. F. 
Published: February 2006

AbstractA surface integral equation (SIE) method is used to calculate the specific absorption rate (SAR) in spherically capped cylindrical models irradiated by an axially incident electromagnetic plane wave (K polarization) in a frequency range for which calculations previously have not been available (80–400 MHz for man models). In the SIE method, the electromagnetic (EM) field relations are formulated in terms of electric and magnetic currents on the surface of the model. The average SAR is calculated from the far scattered EM fields by means of the forward scattering theorem. SAR data calculated by the SIE method agree with data calculated by the extended boundary condition method (EBCM) for frequencies up to 80 MHz (the upper frequency limit of the EBCM) for man models. For rat models exposed to 1–3 GHz radiation, reasonable agreement was also obtained with the limited experimental data available.
The vacuolar potential of characean cells subjected to electromagnetic radiation in the range 200–8,200 MHz
Authors: Barsoum Yousri H. , Pickard William F. 
Published: February 2006

AbstractSingle giant cells of Chara braunii and Nitella flexilis were placed in a microstrip exposure apparatus and subjected to bursts of electromagnetic radiation (carrier frequencies from 200 to 8,200 MHz) at a nominal power level of 100 W/m2. The vacuolar potential was monitored with a micropipette, and offsets as low as 1 μ V could be resolved in real time by suitable filtering and signal averaging; under these conditions, no offsets of the vacuolar potential were detected. At much higher power levels (corresponding to > 2 V rms between microstrip and ground plane), the slow hyperpolarizing ramp reported at lower frequencies could be seen but, because of insufficient power, could not be accurately measured. It appeared to decay beyond 500 MHz and to be absent at and above 950 MHz. To investigate reports that snail neurons irradiated for 1 h at 2,450 MHz and approximately 15.5 W/kg developed lowered membrane resistivities, Characean cells were exposed in the microstrip apparatus for 1 h at 2,450 MHz and 230 W/m2; their membrane resistivities were found to be lowered about 18.5%.
Evidence for electrostatic enhancement of odor receptor function by worker honeybee antennae
Authors: Erickson Eric H. 
Published: February 2006

AbstractPore plates (placoid chemosensillae) on the antennae of dead worker honeybees (Apis mellifera L.) apparently retained a static electric charge that was significantly different from that of the surrounding cuticle. Residual charge resulted in the concentration of airborne particulate matter over the rim of exposed pore plates to the virtual exclusion of such deposition on surrounding cuticle. Postmortem integrity of polar lipids associated with the pore plate and adjacent sense cells is hypothesized as the source of the static potential. Such a lipoidal matrix, if functioning as an electret and if attracting odorous molecules to receptor cells from outside the odor stream of individual receptors, would greatly enhance receptor efficiency of living bees.
Far‐field dosimetric measurements in a full‐sized man model at 2.0 GHz
Authors: Olsen Richard G. 
Published: February 2006

AbstractElectromagnetic dosimetry was conducted in a tissue‐equivalent full‐sized model of man irradiated at 2 GHz inside a microwave‐anechoic chamber. A nonperturbing temperature probe and a gradient‐layer calorimeter were used to determine local and whole‐body specific absorption rate (SAR), respectively. Relatively high SAR values were found in the limbs compared to the axis of the trunk of the model. The calorimeter experiments yielded an average SAR about three times higher than that estimated theoretically for a prolate spheroidal model of man. It is suggested that resonant interactions involving the limbs may be responsible for the disparity between theory and experiment.
The frequency dependence of an analytical model of an electrically stimulated biological structure
Authors: Drago G. P. , Marchesi M. , Ridella S. 
Published: February 2006

AbstractA digital computer simulation has been carried out of the exposure of a cell, modeled as a multilayered spherical structure, to an alternating electrical field. Electrical and electrochemical quantities of possible biological interest can be evaluated everywhere inside the cell. A strong frequency behavior in the range 0–10 MHz has been obtained.
A circular waveguide irradiation system for nonhuman primates: Design and dosimetry
Authors: Olsen Richard G. , de Lorge John O. , Forstall John R. , Ezell Clayton S. 
Published: February 2006

AbstractA 275‐MHz exposure system, consisting of a circular waveguide irradiator and a transparent plastic animal cage, has been developed to accommodate rhesus monkeys weighing up to 15 kg. The vertically oriented waveguide is composed primarily of stainless steel and is fitted with an inner cage fabricated from a tubular section of acrylic plastic. Circularly polarized electromagnetic energy at 275 MHz, either pulsed or continuous wave (CW), can be propagated from the removable top section of the waveguide. The cage is designed to function as the monkey's permanent home. It is fitted with a lever‐actuated behavioral performance device on which the monkey responds according to a predetermined schedule to obtain a daily food ration. The system can be adapted to provide for the collection of metabolic and physiologic data as well. Dosimetric measurements were conducted with six rhesus monkeys weighing 3.0–7.2 kg and with a 4‐kg model. The dosimetric results show that about one‐third of the net incident energy is absorbed by a subject in this system at a normalized specific absorption rate (SAR) of 0.33 (W/kg)/(mW/cm2).
Studies on prenatal and postnatal development in rats exposed to 60‐Hz electric fields
Authors: Sikov M. R. , Montgomery L. D. , Smith L. G. , Phillips R. D. 
Published: February 2006

AbstractA series of three experiments was performed to determine the effects of 30‐day exposures to uniform 60‐Hz electric fields (100 kV/m) on reproduction and on growth and development in the fetuses and offspring of rats. In the first experiment, exposure of females for 6 days prior to and during the mating period did not affect their reproductive performance, and continued exposure through 20 days of gestation (dg) did not affect the viability, size, or morphology of their fetuses. In the second experiment, exposure of the pregnant rat was begun on 0 dg and continued until the resulting offspring reached 8 days of age. In the third experiment, exposure began at 17 dg and continued through 25 days of postnatal life. In the second and third experiments, no statistically significant differences suggesting impairment of the growth or survival of exposed offspring were detected. In the second experiment, a significantly greater percentage of the exposed offspring showed movement, standing, and grooming at 14 days of age than among‐sham‐exposed offspring. There was a significant decrease at 14 days in the percentage of exposed offspring displaying the righting reflex in the second experiment and negative geotropism in the third experiment. These differences were all transient and were not found when the animals were tested again at 21 days of age. Evaluation of the reproductive integrity of the offspring of the second experiment did not disclose any deficits.
Behavioral studies with mice exposed to DC and 60‐Hz magnetic fields
Authors: Davis H. P. , Mizumori S. J. Y. , Allen H. , Rosenzweig M. R. , Bennett E. L. , Tenforde T. S. 
Published: February 2006

AbstractBehavioral measures were evaluated in adult CD‐1 and LAF‐1 mice continuously exposed for 72 h to a 1.5‐Tesla (1 T = 104Gauss) homogeneous DC magnetic field, and in LAF‐1 mice continuously exposed for 72 h to a sinusoidal 60‐Hz, 1.65‐mT (rms) homogeneous AC field. Three types of behavioral tests were employed: (1) Memory of an electroshock‐motivated passive avoidance task was assessed in animals that had been trained immediately prior to the field exposure. The strength of memory was varied either by altering the strength of the electric footshock during training, or by administering a cerebral protein synthesis inhibitor, anisomycin, at the time of training. (2) General locomotor activity was measured using a quadrant‐crossing test immediately after termination of the magnetic field exposure. (3) Sensitivity of the experimental subjects to the seizure‐inducing neuro‐pharmacological agent, pentylenetetrazole, was assessed immediately after the field exposure on the basis of three criteria: (a) the percentage of subjects exhibiting a generalized seizure, (b) the mean time to seizure, and (c) the mean seizure level. The results of these studies revealed no behavioral alterations in exposed mice relative to controls in any of the experimental tests with the 1.5‐T DC field or the 60‐Hz, 1.65‐mT (rms) AC field.
The effect of exposure of acetylcholinesterase to 2,450‐MHz microwave radiation
Authors: Millar David B. , Christopher John P. , Hunter John , Yeandle Stephen S. 
Published: February 2006

AbstractThe effect of 2,450‐MHz pulsed microwave radiation on the enzyme activity of membranefree acetylcholinesterase was studied while the enzyme was in the microwave field. We found no significant effect of microwave radiation on enzyme activity using a wide variety of power densities, pulse widths, repetition rates, and duty cycles. This suggests that simple, direct modification by microwave energy of acetylcholinesterase structure and enzymic activity is not related to microwave alteration of acetylcholinesterase central nervous system levels.
Electromagnetic heating of tissue‐equivalent phantoms with thin, insulating partitions
Authors: Schaubert D. H. 
Published: February 2006

AbstractThe electromagnetic power absorption in tissue‐equivalent phantoms that are used for evaluation of diathermy and hyperthermia applicators is analyzed for the purpose of determining the effect of an insulating partition that is frequently used to facilitate separation of the phantom for thermographic analysis of heating distributions. An analysis that is based on the plane wave spectrum decomposition of the electromagnetic field is applied to a simplified model of the medium. The simplified model is valid whenever the insulating partition does not significantly alter the fields in the medium. The curves that are presented indicate that thin partitions do not significantly alter the power absorption for most situations of therapeutic interest. Data on the effects of partition thickness and electrical parameters are presented for microwave and radiofrequencies of interest for diathermy and hyperthermia.
Microwave bioeffects in the erythrocyte are temperature and pO2 dependent: Cation permeability and protein shedding occur at the membrane phase transition
Authors: Liburdy R. P. , Penn A. 
Published: February 2006

AbstractMicrowave exposure (2450 MHz, 60 mW/g, CW) of rabbit erythrocytes increases Na passive transport only at membrane phase transition temperatures (Tc) of 17–19°C. This permeability effect is enhanced for relative hypoxia which is characteristic of intracellular oxygen tension (pO2 ⩽ 5 mm Hg). Neither the permeability nor the pO2 effects are observed in temperature‐matched (± 0.05°C), sham‐exposed controls. In addition, at Tc, microwave exposure is observed to induce the shedding or release of two erythrocyte proteins not seen in sham‐exposed controls. Moreover, the enhanced shedding of at least seven other proteins all of molecular weight ⩽ 28,000 D was detected in the microwave‐treated samples. Using sensitive silver staining we estimate that approximately 450 fg of protein were shed per erythrocyte. These results demonstrate that temperature and pO2 are important influences on both functional and structural responses of cell membranes to microwave radiation.
The membrane potential of Characean cells exposed to amplitude‐modulated, low‐power 147‐MHz radiation
Authors: Brunkard Kathleen Montaigne , Pickard William F. 
Published: February 2006

AbstractThe membrane potential of isolated cells of Chara braunii or Nitella flexilis was monitored while the cells were exposed, at nominal power densities from 2 to 1,000 W/m2, to 147‐MHz radiation amplitude modulated at frequencies from 4 to 64 Hz. Phase‐sensitive detection was used to seek radiation‐correlated changes in the membrane potential, and none were apparent under any of the conditions used in this investigation.
Vacuolar hyperpolarizing offsets in Characean cells exposed to mono‐ and bichromatic CW and to squarewave‐modulated electromagnetic radiation in the band 200–1,000 MHz
Authors: Gokhale Ashok V. , Brunkard Kathleen Montaigne , Pickard William F. 
Published: February 2006

AbstractSingle giant cells of the algae Chara braunii and Nitella flexilis were exposed to bursts of electromagnetic radiation (monochromatic CW, bichromatic CW, or squarewave‐modulated) in the band 200–1,000 MHz while their vacuolar potentials were monitored using micropipettes. The slow hyperpolarizing response that was observed seemed to be linear in the power deposited in the vicinity of the cell, to be otherwise indifferent to irradiation frequency or modulation, and therefore to be thermal in origin.