FIGURE 2.

(a–c) Representative x-t (cyan) and y-t (magenta) traces of a bead obtained at the trap stiffness of 0.024, 0.056, and 0.090 pN/nm, respectively. The bold bar indicates the time period where bead contact procedure was performed. Downward arrowheads indicate the type I movement. In a, upward thin arrow indicates the bead motion in the y direction; black arrowhead and black double arrowhead indicate the forward and rearward movements. In b, the bead movements occurred toward the end of the record. In c, the bold arrow indicates the small random motion of the bead. In d, a representative x-t and y-t traces of an adherent bead. In e–g, the v_x-t (cyan) and v_y-t (magenta) traces derived from the displacement traces in a–c, respectively. Stars in e indicate the parts that are shown with an expanded time scale in h and i, and those in f show the part shown in m. In h–k, the v_x-t curves with an expanded timescale obtained at 0.024 pN/nm; l and m, at 0.056 pN/nm. Abscissa indicates time in seconds.