Sherman Fairchild, new home for stem cell and regenerative biology (the biggest undergraduate life-sciences concentration), buzzed with activity on a fall evening. A $65-million to $70-million rehab (see <a href="http://harvardmagazine.com/2010/11/gut-renovation">“Gut Renovation”</a>) brought members of this first cross-school (Medicine and Arts and Sciences) department together in Cambridge sooner than would have happened at the planned Allston science center site. 