Study type: Medical/biological study (experimental study)

Role of field intensity in the biological effectiveness of millimeter waves at a resonance frequency. med./bio.

Published in: Bioelectrochem Bioenerg 1997; 43 (1): 27-33

Aim of study (acc. to author)

To replicate the effect of low-intensity millimeter waves of previous studies on isolated nerve function and to characterize its dependence on irradiation intensity. Exposures were accompanied by a high-rate electrical stimulation of the nerve.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 41.34 GHz
Modulation type: pulsed, CW
Exposure duration: 2 HRS trials of 23 min separated by an interval of 53 min

Exposure 1

Main characteristics
Frequency 41.34 GHz
Type
Exposure duration 2 HRS trials of 23 min separated by an interval of 53 min
Modulation
Modulation type pulsed, CW
Pulse width 0.2 ms
Pulse type rectangular
Additional info

paired pulses with an interval of 9 ms between the pulses in a pair: a) 4 pairs/s = LRS b) 20 pairs/s = HRS

Exposure setup
Exposure source
Distance between exposed object and exposure source 52 mm
Chamber exposure bath maintained at 11 to 12°C filled with minerial oil and equipped with two pairs of saline bridge electrodes
Sham exposure A sham exposure was conducted.
Additional info first HRS trial without millimeter wave exposure, the second one with millimeter wave exposure or sham exposure
Parameters
Measurand Value Type Method Mass Remarks
power density 0.02 mW/cm² - measured - -
power density 0.1 mW/cm² - measured - -
power density 0.5 mW/cm² - measured - -
power density 2.6 mW/cm² - measured - -

Reference articles

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

Millimeter waves had no effect on the conditioning compound action potentials, but significantly attenuated the high-rate electrical stimulation-caused decrease of the test compound action potentials (conditioning/test compound action potential (CAP), i.e. the CAPs evoked by the first and the second stimuli in a pair, respectively). The magnitude of this effect was virtually the same at field intensities of 0.02, 0.1, and 2.6 mW/cm². Exposure at 0.5 mW/cm², however, did not cause statistically significant changes.
The findings are consistent with earlier observations of this millimeter wave effect and provide further evidence for its nonthermal mechanism.

Study character:

Study funded by

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