assertion  retraction  graph  subject       predicate          object                datatype    annotation
1          0           graph  DOID:0050748  oio:creation_date  2012-09-18T02:00:45Z  xsd:string  
1          0           graph  DOID:0050746  oio:creation_date  2012-09-18T02:00:45Z  xsd:string