Pure focus by Matthew Modoono November 2, 2016 Share Facebook LinkedIn Twitter Kendra Marcus, a PhD student, works on a water purification system in the Mattos lab in Hurtig Hall on Tuesday. Photo by Matthew Modoono/Northeastern University Doctoral student Kendra Marcus, PhD’17, works on a water purification system in the Mattos Lab in Hurtig Hall on Tuesday. Photo by Matthew Modoono/Northeastern University