Week 31 – A research group led by Gabriel Popescu developed a new optical method for measuring growth of individual cells during the cell cycle. Although growth patterns vary within cell populations, knowledge of individual growth is still limited. Optical methods that do measure single cell growth often measure cell volume and assume this is a good indicator for cell mass. The new method called SLIM allows scientists to calculate dry cell mass more directly. The scientists demonstrate the technique for E.coli and U2OS cells in a publication in the early edition of PNAS.