And in both cases, what the patent means is we have an abnormality in which either one of these two ducts, either one of these two shuts do not actually close off. They remain open for the duration of that individual's lifetime unless it's actually surgically fixed. So let's begin by discussing the patent ductus arteriosis. So once again, normally what happens is as soon as the oxygen rushes into the lungs of that fetus, the lungs begin to produce the protein known as brady kinan. And bradykinan only functions in the presence of plentiful oxygen. So what brady kinan does is it moves into the ductus arteriosis that now contains a bunch of oxygen molecules and it uses that to close off and see loft the ductus arteriosis.