1. 1st Division of Internal Medicine & Infectious Diseases Unit, University General Hospital of Ioannina, Faculty of Medicine, University of Ioannina, 45500 Ioannina, Greece
2. School of Electrical and Computer Engineering, National Technical University of Athens, 15773 Athens, Greece
3. Faculty of Medicine, University of Ioannina, 45110 Ioannina, Greece