BOSTON — The head of Massachusetts' newly formed marijuana regulatory board says the panel is committed and energized as it begins to tackle the many challenges around legal pot sales.The Cannabis Control Commission is scheduled to hold its first meeting Tuesday.In an interview with The Associated Press, commission chair Steven Hoffman said the panel would do everything it could to meet deadlines set in the marijuana law, while adding that he would have "no credibility if I said with 100 percent certainty we are going to do so."