Measuring gastric emptying: comparison of 13C-octanoic acid breath test and scintigraphy.

The aim of this study was to compare scintigraphy, the standard method, and the (13)C-octanoic acid breath test (OBT) for measuring gastric emptying. Patients with functional dyspepsia (N = 21, 8 men and 13 women; ages, 40-75) underwent standardized dynamic scintigraphy and OBT. Scintigraphic images were obtained for 90 min and breath samples for 4 hr.

DNA overstretching transition: ionic strength effects.

As double-stranded DNA is stretched to its B-form contour length, models of polymer elasticity can describe the dramatic increase in measured force. When the molecule is stretched beyond the contour length, it further shows a highly cooperative overstretching transition. We have developed a theoretical description for this transition by coupling the two-state model and the elasticity theory proposed earlier by others.