Paradoxical Brownian motion in a microfluidic device: Absolute negative mobility R. Eichhorn, A. Ros, J. Regtmeier, T. Tu Duong, P. Reimann and D. Anselmetti Eur. Phys. J. Special Topics, 143 (2007) 159-164 Published online: 12 May 2007 DOI: 10.1140/epjst/e2007-00083-1