The experts at N.I.H.say you may have to repeat this process a few times.

VOA: special.2010.03.31

The traditional spelling is d-o-u-g-h-n-u-t but people often just spell it d-o-n-u-t.

VOA: special.2010.04.12

Doctor Anthony Fauci at N.I.H.called the findings an important step forward.

VOA: special.2009.09.30