So a 74xx244 works at a commercial operating temperature, while a 54xx244 which is the same logic device [maybe the same pinout, and package] will continue to operate to the military operating temperature range [which is wider].
A distemper vaccine is more than a preventive against canine distemper virus. This vaccine, considered a core vaccine for all dogs in the United States, also protects against a host of other diseases you may not know your dog is susceptible to. These can include adenovirus, parvovirus, and others.
Distemper is a deadly disease usually affecting dogs and cats. Though both types are commonly confused as the same, Canine Distemper in dogs and Feline Distemper in cats are caused by different viruses. For Canine Distemper, the virus involved is paramyxovirus.