A multi-dimensional information repository storing data structures and tags associated with individual ones of the data structures. The method according to the invention uses a nematode which has been brought into contact with the test substance and which is then exposed to a local thermal stimulus. The at least one medical device interface is coupled to the housing for interfacing with the at least one medical device. The column path circuit is initialized in response to the column reset signal. The phosphor sheet, LED layers, and, optionally, the carrier substrate are then diced to separate the LEDs.