## 1 Introduction
### Non-Thermal MMW Wave Irradiation Does Not Cause Genomic DNA Double-Strand Attentions  
The effects of MMW irradiation were observed to be persistent even beyond 3-6 h after termination of MMW exposure on the irradiated cells across six separate experiments. Evidently, thermal effects can be ruled out as the same non-thermal threshold powers were involved as reported earlier [17]. Irradiations of MMW under 1 mW/cm\({}^{2}\) are deemed not to give rise to thermal effects in living cells [14]. As our experiments involved power densities around 1 mW/cm\({}^{2}\) placing the results in a non-thermal range (also demonstrated in experiments later in this article), it is necessary to investigate other possible mechanism(s) responsible for the decreased growth rate of MMW irradiated cells. Therefore, the next step of the investigation was to check for the possible presence of genomic alterations arising due to radiation in the treated cells. In this direction, we examined for genomic DNA perturbations using the \(\Delta rad52\) deletion strain. Rad52 is a protein required to repair DNA double-strand breaks. Rad52p mediates Rad51p function in homologous recombination repair (HRR) in both yeast _Saccharomyces cerevisiae_ and in mammalian cells of mice and humans [18]. Double-strand breaks (DSBs) are one of the most dangerous forms of DNA damage and are known to cause gross chromosomal rearrangements, which are hallmarks of human cancers [19]. [PERSON] et al. highlighted the importance of human RAD52 for maintaining genome integrity [20]. In the absence of this protein in the \(\Delta rad52\) deletion strain, yeast cells reportedly die upon irradiation by DNA damaging electromagnetic spectra [21; 22]. Irradiation of WT and \(\Delta rad52\) at the minimal threshold powers of 5 dBm (0.83 \(\pm\) 0.02 mW/cm\({}^{2}\)) and frequency (105 GHz) for 5 and 6 h respectively as indicated from the previous experiment did not yield any differences in colony growth profiles between the two. To remove the possibility that low power (corresponding to 0.83 \(\pm\) 0.02 mW/cm\({}^{2}\) surface power density) at 105 GHz (see Table 1) was unable to unravel any differences in growth profiles both WT and \(\Delta rad52\) cells and were subsequently exposed to 90 GHz MMW at 5 dBm power (corresponding to -1.0 mW/cm\({}^{2}\) surface power density) (see Table 1) for 6 h and subsequently incubated under physiological conditions for analyses of serially diluted colony growth profiles. It was observed that both types of cells showed similar colony growth profiles (Figure 2) even after serial dilutions were made to unravel any low intensity differences, which may have been overlooked due to cell numbers; demonstrating  
\begin{table}
\begin{tabular}{c c c c} \hline
**Frequency (GHz)** & **Power Density (mW/cm\({}^{2}\))** & **SAR (W/kg)** & **Time of Irradiation (h)** \\ \hline
85 & 1.39 \(\pm\) 0.03 & 3.38 & 6 \\ \hline
95 & 1.04 \(\pm\) 0.02 & 2.61 & 6 \\ \hline
105 & 0.83 \(\pm\) 0.02 & 2.08 & 6 \\ \hline
105 & 0.83 \(\pm\) 0.02 & 2.08 & 5 \\ \hline \end{tabular}
\end{table}
Table 1: Average energy flux at the aperture of the antenna for different frequencies (see an explanation and calculation in material and methods).  
that reduced cell growth is not accountable to genetic DNA damage of the treated cells. The absence of Rad52p didn't show any significant effect on the cells' growth after treatment indicating non-ionizing MMW radiation does not cause directly manifesting permanent genomic DNA double strand breaks/alterations, while other indirect DNA alterations are possible through regulatory protein networks as discussed later in the article.