FIG. 3.

(a) The dumbbell, kinked, half-dumbbell, and folded DNA conformations in extensional flow field at Wi = 3.4. Images are spaced at 0.13 s. Molecular extension of the last molecule in the first row is 13.9 μm. Reproduced with permission from Perkins et al., Science 276, 2016 (1997). Copyright 1997 The American Association for the Advancement of Science.²⁰ ((b) and (c)) Time course of the DNA extension extracted from individual DNA molecules under the same flow conditions; (b) Wi = 2, (c) Wi = 48. The molecules were categorized with respect to their transient molecular conformations (shown in (a)), as indicated by the colors of the solid lines. The solid black points represent the ensemble average extension, which increases with Wi (cf. (b) and (c)). Note that we used Wi number in the figure caption to refer to De number indicated in the figure, following the discussion given in Section II A. Reproduced with permission from D. E. Smith and S. Chu, Science 281, 1335 (1998). Copyright 1998 The American Association for the Advancement of Science.⁷³