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.
Canine distemper is a very contagious and deadly disease caused by a virus. Dogs and ferrets as well as certain species of wildlife, such as raccoons, wolves, foxes, and skunks, are at risk. Although there is no cure for distemper, the most important fact to remember is that it is preventable through vaccination.