Brian Lipworth1, Sunny Jabbal2. 1. Scottish Centre for Respiratory Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee DD1 9SY, UK. Electronic address: b.j.lipworth@dundee.ac.uk. 2. Scottish Centre for Respiratory Research, School of Medicine, University of Dundee, Ninewells Hospital, Dundee DD1 9SY, UK.