# Sensitivity of Cell Cultures on Time-Varying Low-Frequency Magnetic Field Changes
## 3 Results and Discussion
### The Validity of the Maximal Biological Effect  
The results show that different \(B_{\mathrm{AC}}/B_{\mathrm{DC}}\) ratios do not significantly affect the mean value of the response rate parameter \(S\) [%]. The hypothesis, Section 3.4 letter (b), that the maximum biological effect occurs if the amplitude of alternating component \(B_{\mathrm{AC}}\) of applied CMF is 1.8 times higher than the amplitude of the static component of the field \(B_{\mathrm{DC}}\), is not confirmed, Figures 8 and 9. The statistical evaluation points to the influence of the frequency change on the response of the biological system. However, it did not confirm the maximum response of the system at the cyclotron resonance frequency for calcium ions from the first series of experiments. The most pronounced effect is observed at a frequency of 34.89 Hz and a frequency of 24.89 Hz. This resonance frequency shift may be caused by a different value of the Earth's magnetic field flux density than was measured. The value was measured at only one place in the incubator, approximately at the position of sample C, representing  
Figure 8: Means and 95% Bonferroni intervals of 2 series of experiments. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Frequency [Hz]**}} & \multicolumn{8}{c}{**Subgroups**} \\ \cline{2-11}  & \multicolumn{4}{c}{**Homogeneous Subgroups**} & \multicolumn{8}{c}{**Statistically Significant Difference in S**} \\ \cline{2-11}  & **1** & **2** & **3** & **4** & **5** & **6** & **7** & **8** & **9** & **10** \\ \hline \hline f1 & 24.89 & & & & & & & & & & \\ \hline f2 & 27.39 & & & & & & & & & & \\ \hline f3 & 28.64 & & & & & & & & & & \\ \hline f4 & 29.26 & & & & & & & & & & \\ \hline f5 & 29.57 & & & & & & & & & & \\ \hline f6 & 29.89 & & & & & & & & & & \\ \hline f7 & 30.20 & & & & & & & & & & \\ \hline f8 & 30.52 & & & & & & & & & & \\ \hline f9 & 31.14 & & & & & & & & & & \\ \hline f10 & 32.39 & & & & & & & & & & \\ \hline f11 & 34.89 & & & & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Subgroups according to the response rate parameter \(S\). 380 mm from the edge samples. At this distance, the \(B_{\rm DC}\) value could, and probably would be changed, causing further discrepancies in observed results. Likewise, the \(B_{\rm DC}\) value changes over time--four months passed from measuring the value used in the calculations to executing the experiments. There were seven days between the experiments with the frequencies with the most pronounced effect, f1, and f11. Another non-negligible factor is the unfulfilled assumption of the static \(B_{\rm DC}\)'s collinear direction and the magnetic field's alternating \(B_{\rm AC}\) component. Unfortunately, this fact was not verified experimentally. Thanks to the location of the coils, the alternating component has a perpendicular direction to the Earth's surface. However, the direction of the static component could be influenced via the metal shielding between the coils. This ferromagnetic component can cause deformation of the induction lines of the vertical component of the geomagnetic field, thus disrupting its collinearity with the alternating component of the magnetic field created by the applicator. The second factor is that the edge samples are not located in the region of parallel induction lines of alternating components of the magnetic field--their parallelism is determined at a distance greater than the diameter of the coil cavity. In the used exposition system, more than 135 mm from the end of the coil winding would correspond to the parallelism of the induction lines. However, samples E and A are 120 mm from the applicator's edge. Statistical evaluation of the second series of experiments confirmed that different \(B_{\rm AC}/B_{\rm DC}\) ratios do not significantly affect the mean value of the response rate parameter \(S\) [%].