The pathogenesis of ectopic gastric mucosa is a matter of debate between a congenital-embryological-and an acquired origin-consecutive to a gastroesophageal reflux (GER) like Barrett's esophagus -, the most commonly accepted theory being that these areas are embryological remnants.
Standard size latex filled helium balloons stay afloat for approx 8 - 12 hours, metallic helium filled balloons float for 2-5 days. I have found that a 36 latex helium filled balloon can stay afloat for a number of days due to the thickness of the balloon and the massive quantity of helium.
How long will my heart valve last? Mechanical valves in some patients have lasted as long as 25 years without problems.1 So, it is possible that your new artificial valve could last for the rest of your life. But in some cases, a valve has to be replaced within a matter of years or months, for a number of reasons.