From the 1970s to the first decade of the 21st century, the Thayer School saw expansion into new fields such as nanotechnology and biochemical engineering, as well as collaboration with such nearby institutions as Dartmouth Medical School, the Dartmouth-Hitchcock Medical Center, and the Cold Regions Research and Engineering Laboratory. In the early first decade of the 21st century, the core curriculum for undergraduates was revamped under Dean Lewis Duncan (1998–2004), making the school's offerings more accessible to non-major Dartmouth students. The MacLean Engineering Sciences Center (ESC), completed in 2006, was a $21 million project to expand the school's classrooms and research centers.