In piston-pump drug-delivery devices, changes in friction between the piston and vial in which it moves may be reduced andor compensated for by suitable surface coatings andor feedback control. The avatar can be defined using any suitable approach, including by providing measurements of the user’s body or extracting measurements from photographs of the user. The endpoint address information can then be used to add the new participants, media components, and or network access device. Another valve or series of valves control condensate collection by the fuel cell system, and allows the purging of the anode recirculation loop.