1. Faculty of Medicine, University of Ioannina , 45110 Ioannina, Greece
2. Electronics-Telecommunications and Applications Laboratory, Physics Department, University of Ioannina, 451 10 Ioannina , Ioannina, Greece
3. Section of Condensed Matter Physics, Department of Physics, National and Kapodistrian University of Athens, Panepistimiopolis, 157 84 Zografos , Athens, Greece
4. Michaelidion Cardiac Center, 2nd Department of Cardiology and Michaelidion Cardiac Center, Medical School, University of Ioannina , 45110 Ioannina, Greece