ISSN:0197-8462    

DOI:10.1002/bem.2250060202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0197-8462    

DOI:10.1002/bem.2250060203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe spatial distribution of the specific absorption rate (SAR) was measured in a full‐scale model of man using implantable electric field probes. The model was exposed in the near‐field of linear and aperture antennas at 350 MHz. Effects of the wave polarization, antenna position and antenna gain on the SAR distribution and the average SAR in the whole‐body and body parts are rep

ISSN:0197-8462    

DOI:10.1002/bem.2250060204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe permeability of the blood‐brain barrier to high‐ and low‐molecular‐weight compounds has been measured as a function of continuous‐wave (CW) and pulsed‐microwave radiation. Adult rats, anesthetized with pentobarbital and injected intravenously with a mixture of [14C] sucrose and [3H] inulin, were exposed for 30 min at a specific absorption rate of 0.1 W/kg to 1.7‐GHz CW and pulsed (0.5‐μs pulse width, 1,000 pps) microwaves. After exposure, the brain was perfused and sectioned into nine regions, and the radioactivity in each region was counted. During identical exposure conditions, temperatures of rats were measured in eight of the brain regions by a thermistor probe that did not perturb the field. No change in uptake of either tracer was found in any of the eight regions as compared with those of sham

ISSN:0197-8462    

DOI:10.1002/bem.2250060205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe relative transparency of biological materials to high‐frequency electromagnetic waves has encouraged the development of new systems for imaging. This report describes experiments of microwave tomography conducted on a prototype. The object to be analyzed is submerged in water and is illuminated by a plane wave. The total electric field is analyzed by a microwave camera. The recorded data are then processed numerically in order to reconstruct the image that corresponds to the distribution of equivalent currents in a defined plane of a section. Experiments have been conducted on isolated kidneys with and without perfusion. The influence of the perfusing solution temperature has also been studied. These experiments show the potential of this system, especially through the correlation between microwave images and the biological structures. They also confirm previous results concerning spatial resolution and depth of exploration. Finally, the results demonstrate the influence of temperature and support the applicability of this imaging system in non‐invasive thermometry, especially for clinical hyperther

ISSN:0197-8462    

DOI:10.1002/bem.2250060206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractLow‐voltage electric fields were measured in conductive tissue culture media using three techniques: voltage slope, current density‐conductivity, and dipole methods. All three methods tested yielded comparable results. However, all three techniques have associated errors. These errors fall into three major categories: 1) those associated with the measurement equipment, 2) those associated with electrodes, and 3) errors in cross‐sectional area measurements. Each source of error is discussed so that all can be taken into account during construction and/or testing of exposure equi

ISSN:0197-8462    

DOI:10.1002/bem.2250060207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThere has been considerable recent interest in the question of effects of constant magnetic fields (CMF) on living organisms. The possible alteration of the physiochemical properties of water appears to be one example of such an influence. The dielectric constant, pH, and surface tension of water exposed to CMF action were studied. The results fail to confirm the changes observed by some authors. Controversial opinions on this problem are also summarized and discussed.

ISSN:0197-8462    

DOI:10.1002/bem.2250060208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractBoth 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

ISSN:0197-8462    

DOI:10.1002/bem.2250060209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractPotassium ion influx was measured by monitoring42KCI uptake by Chinese hamster ovary (CHO) cells grown in suspension culture and exposed in the culture medium to 60–Hz electromagnetic fields up to 2.85 V/m. In the presence of the field CHO cells exhibited two components of uptake, the same as previously observed for those grown under normal conditions; both these components of influx were decreased when compared to sham‐exposed cells. Although decreases were consistently observed in exposed cells when plotted as logcof uptake, the differences between the means of thecalculatedfluxes of exposed and sham‐exposed cells were quite small (on the order of 4–7%). When standard deviations were calculated, there was no significant difference between these means; however, when time‐paired uptake data were analyzed, the differences were found to be statistically significant. Cells exposed only to the magnetic field exhibited similar small decreases in influx rates when compared to sham‐exposed cells, suggesting that the reduction in K+uptake could be attributed to the magnetic field. Additionally, intracellular K+levels were measured over a prolonged exposure period (96 h), and no apparent differences in intracellular K+levels were observed between field‐exposed and shamexposed cultures. These results indicate that high‐strength electric fields have a small effect on the rate of transport of potassium ions but no effect on long‐term maintenance of

ISSN:0197-8462    

DOI:10.1002/bem.2250060210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractExperiments were conducted using twin‐well calorimetry to determine the averaged whole‐body specific absorption rate (SAR) for rat carcasses exposed to 360, 700, 915, and 2,450 MHz CW radiation in an anechoic chamber. All exposures were done with the long axis of the rat in an E‐polarization. Additional experiments were conducted using a fiber optical temperature probe to determine local SAR in the brain, esophagus, colon, rectum, and tail during microwave exposure. The whole‐body averaged SAR for the radiation frequencies examined follows a nonmonotonic function with 700 MHz as the resonant frequency. This result agrees with previous analytical estimates. Local SARs within the body and tail are nonuniform with significant frequency‐specific hotspots in the colon, rectum,

ISSN:0197-8462    

DOI:10.1002/bem.2250060211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY