RESUMO
Objective To observe changes of cytosolic Ca2+ levels before and after irradiation by ELF pulsed electromagnetic waves and to study the mechanism of these changes.Methods Basing on the result from experiment,time-frequency analysis was applied to analyze the bio-effects of ELF pulsed electromagnetic field on cytosolic Ca2+ levels.Results The PHMx(t,?)isoline of cytosolic Ca2+ levels of the cells before(a)and after(b)irradiation by ELF pulsed electromagnetic field was given.Electrohydrodynamic instability and a crystalline liquid biomembrane were applied to explain the mechanism of biological effects on the cells.Conclusion The cytosolic Ca2+ concentration represents a well-defined pattern of spectrum in time-frequency domain,containing continuous and dispersive spectral components.The circs which was considered to induce bio-effects in time-frequency domain presented two unique properties:the continuous spectrum of cellular Ca2+ fluctuations in time-frequency domain was narrowed by the high-energy spectrum component restrained,and the distribution and the frequencies of the dispersive spectra were changed.Furthermore,the pulse frequencies and intensities producing the bio-effects are discrete and distant.