Modulation type: CW
Exposure duration: continuous for 2, 4, 8, 16, and 24 h
|Exposure duration||continuous for 2, 4, 8, 16, and 24 h|
|Chamber||Four loop antennas on the bottom of the cavity excited travelling waves in TE01 mode, and a metal lid on the top generated standing waves. The incubator-like atmosphere inside the cavity with 95% air and 5% CO2 and >95% humidity was maintained at 37°C. Two cavities for MW and sham exposure were placed in a thermostatic chamber at 38°C (or 40°C?) to prevent condensation on their inner walls.|
|Setup||The cell suspensions were contained in a 140-mm annular culture plate that was irradiated from the bottom. The plate had three radial compartments (inner, middle, and outer ring) allowing different exposure levels for cell suspensions of 3.3, 12.3, and 24.7 ml volume. Thermostated water circulated in a tank beneath the plate.|
|Sham exposure||A sham exposure was conducted.|
|Additional info||A raised temperature control group was incubated at 39°C in a conventional incubator.|
Radiofrequency electromagnetic field can produce an increased level of hsp70 expression at SAR levels above 20 W/kg, even when the effect of raised temperature is taken into account. Cell survival decreased to about 30% after exposure to radiofrequency electromagnetic field for 24h at an average SAR of 100 W/kg. A slight increase in hsp70 was found in cells in both the inner and outer rings of the plate after exposure at SAR levels of 25 and 78 W/kg for 2h. Except for an SAR of 5 W/kg hsp70 expression increased with increasing exposure time. The expression level of hsp70 for the exposed cells was greater than that for the raised temperature control.