New approaches for study of mechanisms of bone demineralization due to microgravity.

: Changes in nano-scale subsystems of rat femurs due to the axial unloading of hindlimbs are studied by means of electron paramagnetic resonance (EPR). After irradiation by 60Co isotopes, the results indicate that weightlessness simulation leads to formation of free radicals in tropocollagen molecules and to a reduction in the amount of CO2 radicals, located on the surface of bioapatite nanocrystals.