1. Institute of Physics, Jagiellonian University, W.S. Reymonta 4,30-059 Kraków, Poland
2. Department of Biophysics, Medical University of Silesia, Sosnowiec, Poland
3. University of Warmia and Mazury in Olsztyn, Faculty of Mathematics and Computer Science, Słoneczna 54, PL-10-710 Olsztyn, Poland