Direct observation of the tube model in F-actin solutions: Tube dimensions and curvatures M. Romanowska, H. Hinsch, N. Kirchgeßner, M. Giesen, M. Degawa, B. Hoffmann, E. Frey and R. Merkel EPL, 86 2 (2009) 26003 Published online: 29 April 2009 DOI: 10.1209/0295-5075/86/26003