Probiotics such as bifidobacteria are typically used in cases when a disease occurs or might occur due to a kill-off of normal bacteria. For example, treatment with antibiotics can destroy disease-causing bacteria, but also normal bacteria in the GI (gastrointestinal) and urinary tracts.
The 3-place Hiller Model 360, military H-23 Raven, was based on the U.S. Navy UH-12, which was first flown in 1948. The H-23 Raven performed as a utility, observation, and MedEvac helicopter during the Korean war.
All branches used helicopters during the war; The USAF & USN used chopppers to rescue downed airmen over North Vietnam, as well as in South Vietnam. The US Army/Marines used choppers for transport, re-supply, evacuations, and aerial gunship attacks during suppport of ground operations.