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Mammalian Muscle Properties

Mammalian Muscle Properties. Madden et al. IEEE J. Oceanic Engr. 29: 706, 2004. Skeletal muscle features. Muscle surpasses artificial actuators only in the fuel delivery Linear actuation Adapted for intermittent duty and stiffness (compliance) control

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Mammalian Muscle Properties

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  1. Mammalian Muscle Properties Madden et al. IEEE J. Oceanic Engr. 29: 706, 2004

  2. Skeletal muscle features • Muscle surpasses artificial actuators only in the fuel delivery • Linear actuation • Adapted for intermittent duty and stiffness (compliance) control • Versatile force control: recruitment + stiffness modulation (w/o feedback) Madden et al. IEEE J. Oceanic Engr. 29: 706, 2004

  3. Hill model : Force dependence on contraction velocity

  4. McKibben muscle

  5. McK muscles • Steel braid wrapped around a rubber tube. • Crimped at ends

  6. 20N/g

  7. Testing

  8. Antagonistic pairs for smooth torque

  9. Friction in the mesh • Filament on filament friction (no sliding relative to the tube)

  10. Properties of McK muscles • 1. Fstatic~ CSA (pro2) • 2. Fstatic~ P • 3. Fstatic is independent of initial length • 4. Fstaticmax~ 1/ao • 5. Fstatic ~ 1/e

  11. Molecular Springs & Ratchets • Spasmoneme of the Vorticella • Acrosome • Actin polymerization Mahdevan, L : Science, 288: 95, 2000.

  12. Spasmoneme of the Vorticella

  13. Actin Spring • Acrosome needs to penetrate egg jelly. • Spring is super-coiled- held twisted by scruin. • Ca++ Ds scruin

  14. Supramolecular ratchets • Pawl and ratchet analogy of actin polymerization • How controlled? In quiescence, profilin is the shut-off switch. Stimulus such as pH D in presence of actin monomers can start. • Listeriaridesthis bus

  15. Overall energy balance

  16. Conducting polymers • Large molecular deformations (strains) induced by current • Reversible Change in oxidation state

  17. ATP SYNTHASE — A MARVELLOUS ROTARY ENGINE OF THE CELL < previousnext >

  18. How does muscle fatigue? • Test of a ‘skinned’ muscle fiber from EDL of rat. • Can activate by direct stimulation of any step in the cascade. Pederson, TH: Science 305: 1144, 2004

  19. F1 ATPase: A rotary motor • Can either make or break ATP, hence is reversible • Torque of 40 pN-nM; work in 1/3 rev. is 80 pn-nM (40 * 2p/3) equivalent to free energy from ATP hydrolysis • Can see rotation by attaching an actin filament

  20. Rotary Cellular Motors • The rotary mechanism of ATP synthase , Stock D, Gibbons C, Arechaga I, Leslie AGW, Walker JECURRENT OPINION IN STRUCTURAL BIOLOGY ,10 (6): 672-679 DEC 2000 • 2. ATP synthase - A marvellous rotary engine of the cell, Yoshida M, Muneyuki E, Hisabori TNATURE REVIEWS MOLECULAR CELL BIOLOGY 2 (9): 669-677 SEP 2001 • 3. The gamma subunit in chloroplast F-1-ATPase can rotate in a unidirectional and counter-clockwise manner Hisabori T, Kondoh A, Yoshida M FEBS LETTERS 463 (1-2): 35-38 DEC 10 1999 • 4. Constructing nanomechanical devices powered by biomolecular motors.C. Montemagno, G Bachand, Nanotechnology 10: 225-2312, 1999.

  21. ATP SYNTHASE — A MARVELLOUS ROTARY ENGINE OF THE CELL < previousnext >

  22. Nature Reviews Molecular Cell Biology2; 669-677 (2001)ATP SYNTHASE — A MARVELLOUS ROTARY ENGINE OF THE CELL < previousnext >

  23. ATP SYNTHASE — A MARVELLOUS ROTARY ENGINE OF THE CELL < previousnext >

  24. Comparative motors

  25. When L>> x, the chain has many bends and is always crumpled in solution – the FJC model applies, with each link approximated as 2 x, and perfectly flexible joints. • To count all possible curved states in a smooth-bending rod in solution- it’s a WLC- supercoiling is possible.

  26. F1 ATPase: A rotary motor • Can either make or break ATP, hence is reversible • Torque of 40 pN-nM; work in 1/3 rev. is 80 pn-nM (40 * 2p/3) equivalent to free energy from ATP hydrolysis • Can see rotation by attaching an actin filament

  27. (www.sciencemag.org/feature/data/1049155.shl).

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