1. School of Mathematical Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia
2. Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia
3. Department of Mathematics and Computer Science, Western Kentucky University, 1906 College Heights Boulevard, Bowling Green, KY 42101-1078, USA