An imaging nanoparticle comprising a plant virus particle having an interior surface and an exterior surface, an imaging agent that is linked to the interior andor exterior surface, and a layer of biocompatible mineral such as silica coated over the exterior surface, is described. In one embodiment, a role structure is used in conjunction with a hierarchical organization structure to allow access rules to be inherited by some of the positions from other positions based upon the relationship of positions within the organization and the roles associated with the positions. A fixing member fixes the stamper to the core material portion. A frequency of the carrier wave is varied for the pulse width modulation. In another example, a communication device comprises a transmitter, a processor, and a memory arranged to store a weighting factor associated with each receiver, channel and rate combination. The lower side walls form two or more lower raceways.