A Rhode Island doctor has pleaded not guilty to violating the state’s social host law in allegedly hosting a drinking party for teenagers at his Barrington home. Bruce Becker, a professor at Brown University’s medical school, appeared in court Wednesday on a misdemeanor charge of procuring alcohol for a minor. Police said they found beer, vodka, and champagne after breaking up the July 30 party. Police said Becker told the teenagers to run when officers approached. Becker told police he purchased soft drinks for his son’s 18th birthday party, but did not know alcohol was present.