"Since 1991, however, measurement of in vivo NO production in humans have been proven to be technically feasible by means of ex vivo manoeuvres, i.e. by sampling the exhaled breath and analysing it for NO content using a chemiluminescent NO analyser"

http://www.erj.ersjournals.com/cgi/reprint/12/5/1005.pdf

Chemiluminescence is what makes the glow worm glow, but in that case it's called bioluminescence.


"Time is what prevents everything from happening at once" - John Wheeler