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Figure 7: Geometric and structural response of a 10-month-old double-null fiber to tensile loading. The same region of the fiber, imaged using phase-contrast microscopy, is shown at five different deformations. Fiber strains, radial strains, and sarcomere lengths are reported to the right of the fiber for each deformation. Fiber displays both misaligned Z-lines as well as discontinuity between fiber, sarcomere, and radial strains. A sample region of the fiber that displays the basketweave pattern characteristic of misalignment is marked with a white box. The boxed region has been also computationally enlarged 2x for clarity. As for desmin-null fibers, double-null fibers display dramatically more debris on their external membrane compared to wild-type fibers. Bar = 50 μm.