30 Hz, Could It Be Part of a Window Frequency for Cellular Response

They make a review but above all a series of experiments made by themselves using combinations of frequencies or intensities, from which it can be deduced:

The growth of glioma cells is reduced when it is exposed to an electromagnetic field with the Schumann frequencies of the earth (7.8, 14, 20, 26, 33, 39, and 45 Hz) especially at 33 Hz, at an intensity as the smallest of the geomagnetic field, 33 µT (although much greater than that of the Schumann waves themselves, which is an electromagnetic field of one picotesla approx.)

When these gliomas or other cells (neuroblastoma cells and mesenchymal stem cells) are exposed to 20, 30 or 50 Hz, their viability is reduced by 30 Hz (but if you compare what is reduced in gliomas in this and the previous experiment the 33 Hz frequency of the Schumann resonance would be more effective).

From other experiments they have carried out, it is also deduced that cancer cells differ from normal cells in that the low-voltage-dependent calcium channels have been deformed in the former (one of the cell membrane proteins that introduce calcium ions into the cell and that open with very little voltage and are therefore possible targets of electromagnetic waves).