A system and a method for managing electronic contact database are disclosed. on a mixture of a wetting solution and a calcium phosphate powder having a Ca to P molar ratio of 0. The device agent also includes an associator for associating the medical device and the information reader based on the association information. In one embodiment, for instance, the arteriovenous graft system includes a first valve device positioned at the arterial end and a second valve device positioned at the venous end. The electrically conductive substrate further comprises a dopant. A monitoring system also detects moving vehicles in an area, and positions reported by the monitoring means are compared with information being recorded on the computer system, and if these do not correlate, an unregistered vehicle alarm is generated.