3. DNA model
[Larson (2005) J.Rheol. 49, p.1]
coarse graining
      molecular level
      bead-rod model
      bead-spring level


Other mechanisms
      1. viscous drag
      2. entropic spring
      3. B  - Brownian force
      4. HI - hydrodynamic interaction
      5. EV - excluded volume
      6. IV - internal viscosity
      7. SE - self-entanglement