[1] Virginia Polytech Inst & State Univ, Sch Biomed Engn & Sci, Blacksburg, VA 24061 USA
[2] Univ Oklahoma, Hlth Sci Ctr, Dept Geriatr Med, Oklahoma City, OK 73104 USA
[3] Virginia Polytech Inst & State Univ, Sch Biomed Engn & Sci, Blacksburg, VA 24061 USA
[4] Virginia Polytech Inst & State Univ, Dept Biomed Sci & Pathobiol, Blacksburg, VA 24061 USA