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.
Feline distemper, also called panleukopenia, is a highly contagious virus that affects rapidly growing cells, such as those of the digestive system, the nervous system, the lymph tissue, and the bone marrow. It is very similar to the virus that causes parvo disease in dogs.