Ten years after helping open the Chicago office of Loeb & Loeb LLP, partner Douglas N. Masters is moving up. Masters, a 50-year-old intellectual property lawyer, was named Loeb & Loeb’s Chicago office head this month. He replaces Elizabeth L. Majers, who has held the post since April 2012 and is retiring at the end of this year. The position requires Masters to sacrifice practice time in favor of firm time. It’s a tradeoff he’s always been willing to make. “I always think of myself …