The U.S. Patent and Trademark Office rejected two of five patents at the center of the legal battle that threatens to shutter BlackBerry email service in the United States. This marks three times in the past month and twice in two days that the USPTO has issued a negative ruling on a disputed patent from NTP, the patent-holding company that sued BlackBerry maker Research in Motion Ltd. for patent infringement in 2001. U.S. District Judge James Spencer ruled in favor of NTP in 2003, instructing that RIM halt its sales of BlackBerry devices and services in the United States until NTP’s patents run out in 2012. He stayed the ruling, though, pending appeal. Since then, the case has gone through several appeals, and RIM is trying to take the case to the Supreme Court.