“Effect of Intermittent ELF MF on Umbilical Cord Blood Lymphocytes,” Bioelectromagnetics, posted November 15, 2020. A stronger effect seen at lower field strengths. Also: “[O]ur results provide a new example of the biological relevance of the first Schumann resonance frequency (7.8 Hz).”
https://microwavenews.com/papers/nonlinear-elf-mf-effect