この研究は、大腸菌（E.coli）の生存能力及び代謝活性に対する99 GHzミリ波の連続波（CW）放射の影響におけるばく露時間依存性を調べた。光学密度OD660nm=0.1のE. coli懸濁液を生存能力検査に、OD660nm=1.0のものを代謝活性検査に用いた。後進波発信管（BWO)からホーンアンテナにより放射させた99 GHzのCW電磁界は、E. coli液面で0.2 mW/cm2のほぼ理想的なガウスビームであった。その結果、ばく露1時間ではE.coliの生存能力及びコロニー特性に影響はなかった；ばく露19時間では、ユニットを形成するコロニー数が、擬似ばく露群及び対照群に比べばく露群では約2倍高くなったが、E. coliの代謝活性への影響はなかった、などの所見を報告している。
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All experiments were performed on Escherichia coli populations during the logarithmic phase. For cell viability tests two exposure methods were used: 1) exposure was conducted on cells that were spread on agar plates, and 2) exposure was conducted on cells that were suspended in two different culture mediums (PBS (to study the cell death) or LB (to study cell division)). For metabolic activity test exposure (19 h) was conducetd on cells that were suspended in LB medium.
The data showed that 1 hour of exposure to 99 GHz continuous wave electromagnetic field irradiation had no effect on Escherichia coli viability and colony characterisation. In 19 h of exposure, the number of colony forming units was half order of magnitude higher than the sham exposed and the control: In exposed samples, the calculated viable cells in PBS and LB medium were 8.19 x 107 and 1.47 x 109 cells/ml, respectively. In the sham exposed samples, the calculated viable cells in PBS and LB medium were 3.47 x 107 and 8.41 x 108 cells/ml, respectively. However, 19 h of exposure did not affect the metabolic activity.
The authors conclude that exposure of Escherichia coli to millimeter wave 99 GHz irradiation (continuous wave) for a short period did not affect the viability of Escherichia coli bacterial cells. However, exposure for 19 h caused a slight proliferation but did not influence the metabolic activities (of about 90 biochemical reactions that were examined). Hence, the authors assume that the slight proliferation (half order of magnitude) after 19 h of exposure does not have a biological meaning.