bluuebunny/crossref_metadata_2025 huggingface dataset:
The jet in the radio galaxy 3C120: Jet/cloud interactions at parsec scales
Authors: Gómez J. L. , Marscher A. P. , Jorstad S. G. , Agudo I.
Published: February 2006

The radio galaxy 3C 120 appears as one of the best sources to study the emission and propagation of relativistic jets in active galactic nuclei. Muti‐wavelength multi‐epoch observations suggest that this Seyfert 1 galaxy is probably the result of a merger and presents a jet in precession that originates from the accretion of material onto a super massive central black hole. Thanks to its proximity and high activity it is possible to monitor the rapid changing rich inner jet structure with unprecedented spatial and temporal resolutions through very long baseline interferometry observations. The jet is pointing close to the line of sight, and is most probably interacting very dynamically with a cloud of properties intermediate of those of the broad and narrow emission‐line regions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Jets and their surroundings: Inevitable dissipation in high‐redshift jets
Authors: de Young D.
Published: February 2006

As jets pass through the ambient medium, dissipation of jet energy and momentum can occur due to interaction with this medium. This dissipation is mediated through the non‐linear development of global surface instabilities that create a turbulent mixing layer which resides initially on the surface of the jet. This layer expands in thickness with time, and in many cases it can permeate the entire jet volume, resulting in a fully mixed and turbulent jet. It is shown that the development of such dissipative mixing layers is inevitable for all classes of jet: subsonic, supersonic, relativistic, and MHD jets. The growth rates of the mixing layers are given, and it is shown that the development of this dissipative process increases rapidly with increasing redshift of the jets. Implications for highly collimated jets and the unsolved problem of jet content are discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Radio galaxies and type‐2 quasars in the Spitzer Extragalactic First Look Survey
Authors: Lacy M. , Sajina A. , Gates E. , the XFLS Team
Published: February 2006

We use mid‐infrared colour‐colour plots made with data from the Spitzer First Look Survey to explore the emission mechanisms of faint radio sources in that field. Using mid‐infrared colours alone, we are able to see the transition from a starburst‐dominated radio source population at sub‐mJy levels to the radiogalaxy/quasar population at mJy levels. Both FR I and some FR II galaxies show little or no mid‐infrared excess, suggesting they either lack dusty tori, or a strong continuum source to heat them, or both. Objects with hot, dusty tori, most likely radio‐intermediate and radio‐quiet AGN, make up a significant fraction of the faint radio source population. We also discuss the use of mid‐infrared colour‐colour plots to select radio quiet obscured AGN. Early results from imaging the host galaxies of these type‐2 quasars at high spatial resolution with adaptive optics indicates that they, like type‐1 quasars and radio galaxies, are often found to be hosted by giant elliptical galaxies. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The VLA Low‐frequency Sky Survey
Authors: Cohen A. S. , Lane W. M. , Kassim N. E. , Lazio T. J. W. , Cotton W. D. , Perley R. A. , Condon J. J. , Erickson W. C.
Published: February 2006

We present an overview of the ongoing VLA Low‐frequency Sky Survey (VLSS, formerly known as 4MASS). The VLSS will map an area of 9.1 sr covering the entire sky above a declination of –30 degrees (or 75% of the full sky), at a frequency of 74 MHz (4 meter wavelength) with an unprecedented combination of sensitivity and resolution at this low frequency. The observational challenges at this wavelength include radio frequency interference (RFI), ionospheric phase distortions and a large field of view filled with sources. These challenges have been surmounted by a variety of new algorithms. The principle data products from the survey will be a set of publicly available images along with a source catalog of approximately 80 000 objects. Thus we will create an online virtual observatory at this previously unexplored frequency which will complement other major surveys at higher frequencies such as the NVSS. The most efficient way currently know to search for high redshift radio galaxies is to select ultra steep spectrum sources from low frequency surveys. The VLSS represents an excellent opportunity to pursue this method with its unique combination of large sky coverage and very low frequency, which may be especially useful for finding objects at z > 5. The observations are now roughly 50% complete, and we expect to complete most of the rest by late 2005. Current data products and more information are available on our website (URL http://lwa.nrl.navy.mil/VLSS). Basic research in radio astronomy at the Naval Research Laboratory is supported by the office of Naval Research. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Most supermassive black hole growth is obscured by dust
Authors: Martínez‐Sansigre A. , Rawlings S. , Lacy M. , Fadda D. , Marleau F. R. , Simpson C. , Willott C. J. , Jarvis M. J.
Published: February 2006

We present an alternative method to X‐ray surveys for hunting down the high‐redshift type‐2 quasar population, using Spitzer and VLA data on the Spitzer First Look Survey. By demanding objects to be bright at 24 µm but faint at 3.6 µm, and combining this with a radio criterion, we find 21 type‐2 radio‐quiet quasar candidates at the epoch at which the quasar activity peaked. Optical spectroscopy with the WHT confirmed 10 of these objects to be type‐2s with 1.4 ≤ z ≤ 4.2 while the rest are blank. There is no evidence for contamination in our sample, and we postulate that our 11 blank‐spectrum candidates are obscured by kpc‐scale dust as opposed to dust from a torus around the accretion disk. By carefully modelling our selection criteria, we conclude that, at high redshift, 50–80% of the supermassive black hole growth is obscured by dust. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Granada workshop on High Redshift Radio Galaxies: An overview
Authors: Röttgering H. J. A.
Published: February 2006

The Granada workshop on High Redshift Radio Galaxies (HzRGs) gave an excellent overview of the progress that has been made in this field during the last 3 years. Here we briefly review some of the results, with an emphasis on what studies of HzRGs can teach us about the formation and evolution of massive galaxies, clusters and active galactic nuclei (AGN). Of great relevance for this workshop are scenarios that describe certain aspects of the evolution of radio galaxies, including (i) the sequence of events after merging of galaxies that ultimately lead to extended powerful radio sources and (ii) the mass assembly and virialization of the hosting massive galaxies and their associated (proto‐)clusters. Furthermore, I briefly discuss two projects that are important for a further understanding of AGN and high redshift radio galaxies. First, using the MIDI instrument mounted on the VLT Interferometer, the dusty tori of nearby AGN can be studied in the range of 8–13 micron at high angular resolution. The first result on the nearby AGN NGC 1068 as presented by Jaffe et al. (2004) indicated the presence of a hot (T > 800 K), compact (≲1 pc) component, possible identified with the base of the jet and a warm (270 K), well‐resolved (3 × 4 pc) component associated with the alleged torus. Second, LOFAR is a new low frequency radio telescope that is currently being build in the Netherlands and is expected to be operational in 2008. With 50 stations spread over an area of 100 km in diameter, its resolution and sensitivity will be unprecedented in the frequency range 10–240 MHz. LOFAR will be a unique instrument that will impact a broad range of astrophysical topics varying from the epoch of reionisation, to gamma ray bursts and cosmic rays. Surveys with LOFAR will be of paramount importance for studies of HzRGs: It will enable (i) defining samples of radio galaxies with redshifts higher than 6, (ii) observations of starbursting galaxies in proto‐clusters, and (iii) mapping out the low‐frequency radio emission of virtually all northern radio‐loud AGN in revolutionary detail. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Real‐time measurement of RFR energy distribution in the macaca mulatta head
Authors: Burr John G. , Krupp Jerome H.
Published: February 2006

Temperature increases due to absorption of 1.2 GHz, CW, 70 mW/cm2, radio frequency (RF) energy, were measured in 3.3‐cm‐radius homogeneous muscle‐equivalent spheres, M. mulatta cadaver heads (both detached from and attached to the body) and living, anesthetized M. mulatta heads. Temperatures were measured with a Vitek, Model 101 Electrothermia Monitor and temperature distributions were compared to theoretical predictions from a thermal‐response model of a simulated cranial structure. The results show that the thermal response model accurately predicts the temperature distribution in muscle‐equivalent spheres, the distribution of temperature in detached M. mulatta heads when exposed from the back of the head, and the distribution of temperature in attached M. mulatta cadaver heads for animals oriented with body parallel to the H‐field. The temperature distribution in the detached M. mulatta heads varies markedly with exposure orientation, ie, facing forward, backward, or to the side. The orientation of the M. mulatta cadaver body significantly affects the temperature distribution in the head ‐ with H‐field orientation showing high, nonuniform values, and E‐field orientation showing low, uniform values. In live animals blood flow produces a significant short‐term effect on the temperature distribution in the midbrain, but not the cortex. Midbrain temperatures are both significantly higher and lower than the comparable cadaver measurements, depending on location.
Observing‐responses of rats exposed to 1.28‐ and 5.62‐GHz microwaves
Authors: de Lorge John O. , Ezell Clayton S.
Published: February 2006

The effects of microwave irradiation at two different frequencies (1.28 and 5.62 GHz) on observing‐behavior of rodents were investigated. During daily irradiation, eight male hooded rats performed on a two‐lever task; depression of one lever produced one of two different tones and the other lever produced food when depressed in the presence of the appropriate tone. At 5.62 GHz, the observing‐response rate was not consistently affected until the power density approximated 26 mW/cm2 at 1.28 GHz, the observing‐response rate of all rats was consistently affected at a power density of 15 mW/cm2. The respective whole‐body specific absorption rates (SARs) were 4.94 and 3.75 W/Kg. Measurements of localized SAR in a rat‐shaped model of simulated muscle tissue revealed marked differences in the absorption pattern between the two frequencies. The localized SAR in the model's head at 1.28 GHz was higher on the side distal to the source of radiation. At 5.62 GHz the localized SAR in the head was higher on the proximal side. It is concluded that the rat's observing behavior is disrupted at a lower power density at 1.28 than at 5.62 GHz because of deeper penetration of energy at the lower frequency, and because of frequency‐dependent differences in anatomic distribution of the absorbed microwave energy.
Effects of millimeter‐wave radiation on monolayer cell cultures. III. A search for frequency‐specific athermal biological effects on protein synthesis
Authors: Bush L. G. , Hill D. W. , Riazi A. , Stensaas L. J. , Partlow L. M. , Gandhi O. P.
Published: February 2006

A method recently developed in this laboratory has been used to directly expose BHK‐21/C13 cells to high levels of microwave radiation without significant microwave‐induced heating (⩽ 0.1 °C). Monolayer cultures were grown on microwave‐transparent polystyrene coverslips, placed on the open end of a wave guide, and maintained at 37.2 °C during irradiation at frequencies in both the E‐ and U‐bands (average power densities 292 and 177 mW/cm2, respectively). Effects of microwave radiation were assessed at 0.1 GHz increments in the ranges of 38–48 GHz and 65–75 GHz. Protein synthesis was measured in quadruplicate cultures that were allowed to incorporate labeled methionine during the 15‐minute period of microwave irradiation. Autoradiographs of each monolayer culture were scanned along the region corresponding to the longer axis of the wave guide aperture using a microdensitometer to quantify incorporation. Since microwave power incident on the cells was previously shown to vary along this axis according to a cosine2 relationship from zero at each edge of the wave guide to twice the average power density at the center of the wave guide, this technique should reveal biological effects that might only be manifested in narrow amplitude domains or “power windows.” Observations of protein synthesis in monolayer cultures irradiated at 202 closely spaced frequencies in the E‐ and U‐bands failed to reveal changes associated with microwave exposure. Thus no evidence was obtained in support of the existence of frequency‐specific athermal biological effects of microwaves. In addition, no support was found for the existence of amplitude‐specific “power windows”.
In vitro study of microwave effects on calcium efflux in rat brain tissue
Authors: Shelton W. W. , Merritt J. H.
Published: February 2006

In this study we investigated the prospect of microwave‐induced alteration of 45Ca2+ efflux from rat neural tissue at low pulse repetition frequencies and low power densities under in vitro conditions. Rat cerebral tissue, preloaded with 45Ca2+, was exposed to pulsed‐microwave radiation (1‐GHz carrier frequency) according to one of several PRF‐power density exposure schemes: 16 Hz at 0.5, 1.0, 2.0, or 15 mW/cm2, or 32 Hz at 1.0 or 2.0 mW/cm2 average power density. Measurements of radioactivity in the efflux medium and in the tissue sample were used to calculate an efflux value for each sample. The results indicate that the radiation conditions used did not alter calcium efflux in rat brain tissue.
Prolonged microwave irradiation of rats: Effects on concurrent operant behavior
Authors: Lebovitz Robert M.
Published: February 2006

Two measures of performance were used to study the effects of pulse‐modulated microwave radiation (PM MWR) on schedule‐controlled operant behavior of rats: 1) cued (SD), fixed‐ratio (FR) bar pressing for food reinforcement; and 2) noncued (Sd) bar pressing in the absence of food reinforcement. The animals were irradiated and the behavioral data were obtained concurrently, during daily three‐hour sessions, five days per week for six to nine weeks. Each experiment began with a two to three‐week baseline interval of sham irradiation; a two to three‐week interval of sham irradiation followed the irradiation phase. The irradiated animals were exposed to 1.3‐Ghz PM MWR (pulse width of 1 microsecond at 600 pulses per second) at whole‐body, average specific absorbed‐dose rates of from 1.5–6.7 mW/g. Control and irradiated animals were tested in identical, cylindrical waveguide exposure/behavioral assemblies; different groups of irradiated and sham‐irradiated animals were used for each dose rate. At 1.5 mW/g, the levels of SD operant responding by control and irradiated animals were comparable, and showed similar progressive diminutions over the course of each daily session. Sd operant responding was more variable, but again comparable, with both groups showing similar, progressive declines in rate of responding during each session. At 3.6 mW/g, no specific effects on SD operant response rates were observed. However, there was an initial and transient increase in the rate of extinction of Sd responding. At 6.7 mW/g, SD response rates were slightly reduced, whereas there was a major reduction in noncued (Sd) operant responding followed by a sharp rebound during the first post‐MWR week. This marked reduction in Sd operant responding at MWR onset was in contrast to the relative stability and persistence of FR responding for food reinforcement.
Effect of nonionizing radiation on the purkinje cells of the rat cerebellum
Authors: Albert E. N. , Sherif M. F. , Papadopoulos N. J. , Slaby F. J. , Monahan J.
Published: February 2006

In one experiment, Sprague Dawley rats (16–21 days of gestation) and their offspring were exposed to 100‐MHz (CW) electromagnetic radiation at 46 mW/cm2 (SAR 2.77 mW/g) for 4 h/day for 97 days. In another experiment, the pregnant rats were irradiated daily from 17 to 21 days of gestation with 2450‐MHz (CW) microwaves at 10 mW/cm2 (SAR 2 mW/g) for 21 h/day. In a third experiment, 6‐day‐old rat pups were irradiated 7 h/day for five days with 2450‐MHz radiation at 10 mW/cm2. Equal numbers of animals were sham irradiated in each group. Quantitative studies of Purkinje cells showed a significant and irreversible decrease in rats irradiated during fetal or fetal and early postnatal life. In animals exposed postnatally, and euthanized immediately after irradiation, significant decrease in the relative number of Purkinje cells was apparent. However, restoration apparently occurred after forty days of recovery.
The mechanisms of athermal microwave biological effects
Authors: Taylor Leonard S.
Published: February 2006

A brief survey of current ideas about the physical mechanisms of low‐level millimeter/microwave‐biological effects is given, and the experimental evidence supporting these ideas is reviewed. The conjectural models do not yet represent a complete physical theory, but they do counter the idea that low‐level effects are physically impossible and suggest experiments.
Biological effects of a 765‐kV transmission line: Exposures and thresholds in honeybee colonies
Authors: Greenberg Bernard , Bindokas Vytautas P. , Gauger James R.
Published: February 2006

Honeybee colonies exposed under a 765‐kV, 60‐Hz transmission line at 7 kV/m show the following sequence of effects: 1) increased motor activity with transient increase in hive temperature; 2) abnormal propolization; 3) impaired hive weight gain; 4) queen loss and abnormal production of queen cells; 5) decreased sealed brood; and 6) poor winter survival. When colonies were exposed at 5 different E fields (7, 5.5, 4.1, 1.8, and 0.65–0.85 kV/m) at incremental distances from the line, different thresholds for biologic effects were obtained. Hive net weights showed significant dose‐related lags at the following exposures: 7 kV/m, one week; 5.5 kV/m, 2 weeks; and 4.1 kV/m, 11 weeks. The two lowest exposure groups had normal weight after 25 weeks. Abnormal propolization of hive entrances did not occur below 4.1 kV/m. Queen loss occurred in 6 of 7 colonies at 7 kV/m and 1 of 7 at 5.5 kV/m, but not below. Foraging rates were significantly lower only at 7 and 5.5 kV/m. Hive weight impairment and abnormal propolization occur at lower E‐field intensity than other effects and limit the “biological effects corridor” of the transmission line to approximately 23 m beyond a ground line projection of each outer phase wire. Intrahive E fields of 15–100 kV/m were measured with a displacement current sensor. Step‐potential‐induced currents up to 0.5 μA were measured in an electrically equivalent bee model placed on the honeycomb in a hive exposed at 7 kV/m. At 1.8 kV/m body currents were a few nanoamperes, or two orders of magnitude lower, and these colonies showed no effects. E‐field versus electric shock mechanisms are discussed.
Spectroscopic properties of in vivo biological systems: Boson radiative equilibrium with steady‐state nonequilibrium molecular systems
Authors: Illinger K. H.
Published: February 2006

An 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

A 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

This 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

A 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

Human 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

The 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

A 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

The 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

A 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

Single 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

Pore 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

Electromagnetic 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

A 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

A 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

A 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

Behavioral 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

The 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

The 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

Microwave 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

The 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

Single 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.
Effects of microwave exposure on the hamster immune system. III. Macrophage resistance to vesicular stomatitis virus infection
Authors: Rao G. Rama , Cain C. A. , Tompkins W. A. F.
Published: February 2006

Exposure of hamsters to microwave (MW) energy (2.45 GHz, 25 mW/cm2, 1 h) resulted in activation of peritoneal macrophages (PM) to a viricidal state restricting the replication of vesicular stomatitis virus (VSV). The PM from MW‐exposed hamsters were viricidal as early as 1 day after exposure and remained active for 5 days. Immunization of hamsters with vaccinia virus induced viricidal PM by 3 to 4 days and they remained active for 7 days. To test the hypothesis that thermogenic MW exposure results in the release of endotoxin across the intestinal epithelium which subsequently activates PM, hamsters were injected with lipopolysaccharide (LPS) and their viricidal activity was studied. Lipopolysaccharide in vitro (0.2 μg) and in vivo (0.5 μg) activated macrophages to a viricidal state. When administered in vivo, LPS (0.5 μg) activated macrophages as early as 1 day and the activity remained for 3 days. While MW exposure of PM in vitro failed to induce viricidal activity, exposure of PM to LPS in vitro induced strong viricidal activity. This suggests that the in vivo response of PM to MW is an indirect one, which is consistent with the hypothesis that MW‐induced PM viricidal activity may be mediated via LPS. In preliminary experiments, MW exposure resulted in extended survival time for hamsters challenged with a lethal dose of vesicular stomatitis virus, supporting the concept that MW‐activated PM may be a useful therapeutic modality.
Calibration of flat 60‐Hz electric field probes
Authors: Misakian Martin
Published: February 2006

The influence of nearby ground planes, perturbation of surface charge distributions, and fringing fields on the electric field between parallel plates are characterized to define a parallel plate system that can be used to calibrate flat 60‐Hz electric field probes.
Effects of ELF (1–120 Hz) and modulated (50 Hz) RF fields on the efflux of calcium ions from brain tissue in vitro
Authors: Blackman C. F. , Benane S. G. , House D. E. , Joines W. T.
Published: February 2006

We have previously shown that 16‐Hz, sinusoidal electromagnetic fields can cause enhanced efflux of calcium ions from chick brain tissue, in vitro, in two intensity regions centered on 6 and 40 Vp‐p/m. Alternatively, 1‐Hz and 30‐Hz fields at 40 Vp‐p/m did not cause enhanced efflux. We now demonstrate that although there is no enhanced efflux associated with a 42‐Hz field at 30, 40, 50, or 60 Vp‐p/m, a 45‐Hz field causes enhanced efflux in an intensity range around 40 Vp‐p/m that is essentially identical to the response observed for 16‐Hz fields. Fields at 50 Hz induce enhanced efflux in a narrower intensity region between 45 and 50 Vp‐p/m, while radiofrequency carrier waves, amplitude modulated at 50 Hz, also display enhanced efflux over a narrow power density range. Electromagnetic fields at 60 Hz cause enhanced efflux only at 35 and 40 Vp‐p/m, intensities slightly lower than those that are effective at 50 Hz. Finally, exposures over a series of frequencies at 42.5 Vp‐p/m reveal two frequency regions that elicit enhanced efflux—one centered on 15 Hz, the other extending from 45 to 105 Hz.
Effects of continuous‐wave, pulsed, and sinusoidal‐amplitude‐modulated microwaves on brain energy metabolism
Authors: Sanders Aaron P. , Joines William T. , Allis John W.
Published: February 2006

A comparison of the effects of continuous‐wave, sinusoidal‐amplitude‐modulated, and pulsed square‐wave‐modulated 591‐MHz microwave exposures on brain energy metabolism was made in male Sprague‐Dawley rats (175–225 g). Brain NADH fluorescence, adenosine triphosphate (ATP) concentration, and creatine phosphate (CP) concentration were determined as a function of modulation frequency. Brain temperatures of animals were maintained between −0.1 and −0.4°C from the preexposure temperature when subjected to as much as 20 mW/cm2 (average power) CW, pulsed, or sinusoidal‐amplitude modulated 591‐MHz radiation for 5 min. Sinusoidal‐amplitude‐modulated exposures at 16–24 Hz showed a trend toward preferential modulation frequency response in inducing an increase in brain NADH fluorescence. The pulse‐modulated and sinusoidal‐amplitudemodulated (16 Hz) microwaves were not significantly different from CW exposures in inducing increased brain NADH fluorescence and decreased ATP and CP concentrations. When the pulse‐modulation frequency was decreased from 500 to 250 pulses per second the average incident power density threshold for inducing an increase in brain NADH fluorescence increased by a factor of 4—ie, from about 0.45 to about 1.85 mW/cm2. Since brain temperature did not increase, the microwave‐induced increase in brain NADH and decrease in ATP and CP concentrations was not due to hyperthermia. This suggests a direct interaction mechanism and is consistent with the hypothesis of microwave inhibition of mitochondrial electron transport chain function of ATP production.
Effects of 2.45‐GHz microwaves on primate corneal endothelium
Authors: Kues Henry A. , Hirst Lawrence W. , Lutty Gerard A. , D'Anna Salvatore A. , Dunkelberger Gregory R.
Published: February 2006

Both eyes of anesthetized cynomolgus monkeys (Macaca fascicularis) were irradiated with 2.45‐GHz microwaves, either pulsed or continuous wave. In vivo corneal endothelial abnormalities were observed by specular microscopy and confirmed through histologic techniques after a 16‐ to 48‐hour postexposure period. Pulsed microwaves with an average power density of 10 mW/cm2 (equivalent to a specific absorption rate (SAR) = 2.6 W/kg) produced these effects, while levels of 20‐30 mW/cm2 (equivalent to a SAR = 5.3 to 7.8 W/kg) with continuous wave irradiation were required to produce similar changes.