Continuous positive airway pressure (CPAP) machines are used to maintain an open airway in patients diagnosed with obstructive sleep apnea. The machine functions by blowing pressurized air into the airway via mask at a setting determined by sleep study and prescribed by a physician.
Also the second largest impact structure on Earth, the 1.85 billion years old Sudbury crater in Canada, hosts world-class mineral deposits - in this case nickel-rich minerals that were melted and concentrated by the extreme heating caused by the impact.
Puchezh-Katunki crater, 80km. Only the largest craters (20 km or more diameter) are listed below; the rest are listed by geographical region on subsidiary lists. These features were caused by the collision of large meteorites or comets with the Earth. For eroded or buried craters, the stated diameter typically refers to the best available estimate of the original rim diameter, and may not correspond to present surface features.