1. Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Krakow, Poland
2. M. Smoluchowski Institute of Physics, Jagiellonian University, 30348 Kraków, Poland
3. Biophysics and Medical Technology, Department of Physics, The Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway
4. Biomechanics, Department of Structural Engineering, The Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway