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 an extremely contagious and deadly disease spread by infected fleas or bodily fluid. Symptoms include fever, diarrhea, anorexia, vomiting, water/red eyes. Treatment varies as there is no cure, a vaccine is available.