<http://schema.org/dateModified>
"2013-02-25T17:46:54-05:00"^^<http://schema.org/Date>
<http://www.upi.com/Health_News/2013/02/25/Yams-and-sweet-potatoes-are-not-the-same/UPI-33301361832414/?spt=mps&or=3>