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Cellular Effects

Comparison of dose dependences for bioeffects of continuous-wave and high-peak power microwave emissions using gel-suspended cell cultures.

No Effects Found

Pakhomov AG, Gaj ek P, Allen L, Stuck BE, Murphy MR · 2002

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The study found no statistically significant difference between continuous wave and high-peak power microwave exposures on yeast cell density across a wide range of absorption rates, though a trend appeared at the highest levels.

Plain English Summary

Summary written for general audiences

Researchers compared bioeffects of continuous wave and extremely high power pulse microwaves at 9.3 GHz and 1.25 W average power using yeast cell density in agarose gel. Cell density was strongly affected by irradiation and correlated with local temperature rise, but no statistically significant difference between CW and EHPP was found across the SAR range. A trend (P<0.1) for a difference appeared at average SAR of 100 W/kg and higher, corresponding to peak SAR above 20 MW/kg for EHPP.

Why This Matters

The exposures created highly nonuniform but identical heating patterns in the samples. After exposure, researchers sliced the samples perpendicular to wave propagation to separate cell masses exposed at different absorption rates and measured cell density by nephelometry against unexposed controls.

Exposure Details

SAR
3200 to 0.0006 W/kg
Electric Field
0.00157 V/m
Source/Device
9.3 GHz

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextThis study: 3200 to 0.0006 W/kgExtreme Concern - 0.1 W/kgFCC Limit - 1.6 W/kgEffects documented below the Building Biology "No Concern" threshold (0.001 W/kg)FCC limit is 2,667 times higher than this level
A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 9.30 GHz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 9.30 GHzPower lines50/60 HzCell phones~1 GHzWiFi2.4 GHzLogarithmic scale

Study Details

The study compared bioeffects of continuous wave (CW) microwaves and short, extremely high power pulses (EHPP) at the same carrier frequency (9.3 GHz) and average power (1.25 W).

The peak transmitted power for EHPP was 250 kW (0.5-micro s pulse width, 10 p.p.s.), producing the E...

A biological endpoint was the density of yeast cells, achieved after a 6 h growth period in a solid ...

However, the data revealed no statistically significant difference between CW and EHPP samples across the entire studied range of SAR levels (over six orders of magnitude). A trend (P<0.1) for such a difference was observed in slices that were exposed at a time average SAR of 100 W/kg and higher, which corresponded to peak SAR above 20 MW/kg for the EHPP condition. These numbers could be indicative of a threshold for a specific (not merely thermal) exposure effect if the trend is confirmed by future studies.

Cite This Study
Pakhomov AG, Gaj ek P, Allen L, Stuck BE, Murphy MR (2002). Comparison of dose dependences for bioeffects of continuous-wave and high-peak power microwave emissions using gel-suspended cell cultures. Bioelectromagnetics 23: 158-167, 2002.
Show BibTeX
@article{ag_2002_comparison_of_dose_dependences_3290,
  author = {Pakhomov AG and Gaj ek P and Allen L and Stuck BE and Murphy MR},
  title = {Comparison of dose dependences for bioeffects of continuous-wave and high-peak power microwave emissions using gel-suspended cell cultures.},
  year = {2002},
  
  url = {https://pubmed.ncbi.nlm.nih.gov/11835262/},
}
PubMed: 11835262

Cited By (13 papers)

Quick Questions About This Study

The study compared bioeffects of continuous wave and extremely high power pulse microwaves at 9.3 GHz and 1.25 W average power using yeast cell density in agarose gel.
The biological endpoint was the density of yeast cells after a 6-hour growth period in a solid nutrient medium during exposure.
No statistically significant difference was found between continuous wave and high-peak power pulse exposures across the entire range of absorption rates studied, though a trend appeared at the highest levels.
The peak transmitted power for the pulses was 250 kW with a 0.5-microsecond pulse width and 10 pulses per second, producing an electric field of 1.57 MV/m in the waveguide.
The authors noted that the trend at high peak absorption rates could indicate a threshold for a specific non-thermal effect if confirmed by future studies.