1. Australian School of Advanced Medicine, Macquarie University, Sydney, NSW 2109, Australia
2. Department of Mechanical Engineering, School of Engineering, University of Minho, Braga P-4704-553, Portugal e-mail:
3. Department of Mechanical Engineering, School of Engineering, University of Minho, Braga P-4704-553, Portugal
4. Australian School of Advanced Medicine, Macquarie University, Sydney NSW 2109, Australia