It’s a happy new year for Aethon, maker of the TUG, a mobile robot that transports and delivers supplies in hospitals. The Pittsburgh company reports that it grew its customer base for TUG in 2013 with 21 new sites. It just announced a new $3 million investment from Mitsui USA, augmenting an initial $4 million investment in 2012. And late last year, Aethon unveiled a new product, MedEx Tube Track, a patent-pending system that secures and tracks deliveries sent through the pneumatic tube systems used to deliver medications in hospitals.