Gillette Co., Boston, MA, the world’s largest maker or razor blades and batteries, said on Tuesday that profit rose in the first quarter on the weaker dollar and consumers stocking up on batteries amid Homeland Security concerns.But the company also said it expected sales of Duracell batteries, which rose 16% in the quarter despite a price cut, to slow during the year as consumers use up excess batteries. In January, Gillette’s Duracell unit decided to cut prices on its popular AA- a...