404. That’s an error.

The requested URL /bookmarks/mark?op=add&bkmk=http%3A//ajplung.physiology.org/content/284/1/L69&title=Fibrinolysis-inhibitory%20capacity%20of%20clot-embedded%20surfactant%20is%20enhanced%20by%20SP-B%20and%20SP-C was not found on this server. That’s all we know.