A system for storing fuel in a handheld device that has a housing made up of a set of pieces that define a receptacle inside which are housed a plurality of electronic circuits and a fuel cell stack. A network processor may receive a command to perform a tree operation on a tree on one or more of multiple threads. In addition, the time tracking tool may track a continuous time an issue has been in need of resolution, track a working time that indicates an amount of time spent working on resolving the issue, and provide alerts based on application of one or more alert trigger rules to the tracked continuous time and the tracked working time. Provided also as part of this invention are pharmaceutical products and kits for inducing formation of new blood vessels in the mammal. The plunger includes four crimping jaws which slide against angled surfaces of the plunger.