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.
Sikorsky UH-60 Black Hawk. The Sikorsky UH-60 Black Hawk is a four-bladed, twin-engine, medium-lift utility helicopter manufactured by Sikorsky Aircraft. Sikorsky submitted the S-70 design for the United States Army's Utility Tactical Transport Aircraft System (UTTAS) competition in 1972. The Army designated the prototype as the YUH-60A and selected the Black Hawk as the winner of the program in 1976, after a fly-off competition with the Boeing Vertol YUH-61.