There are many medical reasons that can cause black stools that are tarry with a foul smell, but sometimes dark stools are caused by eating certain foods or taking iron supplements. However, black stools can also be a result of bleeding, and the darker color indicates that the blood could be coming from a point in the upper gastrointestinal tract.
Gertrude Levandowski survived a 96-hour procedure at a Chicago hospital to remove a giant ovarian cyst; the longest surgery. The second longest surgery ever was 40 hours long and that was to remove 6 limbs from a 8 limed baby in India. But the most common longest surgery is spinal cord surgery it is a 14 hour surgery.
The longest duration achieved on multiple missions, more than two years, was logged by cosmonaut Sergei Krikalev over the course of his six missions. U.S. astronaut Peggy Whitson holds the cumulative female record for most time spent in space on multiple flights with 376 days and she is now training to launch on her third flight in March 2016. Cristoforetti has set more than duration records during her Expedition 42/43 stay on the station, a mission that ESA named Futura.