Complex sentence: From 1990-1991, he held a post-doctoral fellowship at UNC Medical School at Chapel Hill, North Carolina and began his academic career at Aston University, firstly as lecturer from 1991-1997 and then as Reader in Pharmaceutical Sciences (1997-1999).
Split into simpler sentences: From 1990-1991, he held a post-doctoral fellowship at UNC Medical School at Chapel Hill, North Carolina. He began his independent academic career at Aston University, firstly as lecturer from 1991-1997 and then as Reader in Pharmaceutical Sciences (1997-1999).