Simplify the following text for a Grade 13 native English-speaking person.
Original: After his work at Fremantle Hospital , Marshall did research at Royal Perth Hospital ( 1985-86 ) and at the University of Virginia , USA ( 1986-Present ) , before returning to Australia while remaining on the faculty of the University of Virginia .
Simplified: After this work at Fremantle Hospital , Marshall did research at Royal Perth Hospital ( 1985-86 ) and at the University of Virginia , USA ( 1986-1996 ) , before going back to Australia .