Bacterial flagella assume different helical shapes during the tumbling phase of a bacterium but also in response to varying environmental conditions. Force-extension measurements by Darnton and Berg explicitly demonstrate a transformation from the coiled to the normal helical state (N.C. Darnton, H.C. Berg, Biophys. J. 92, 2230 (2007)). We here develop an elastic model for the flagellum based o...

Granular media (GM) present locomotor challenges for terrestrial and extraterrestrial devices because they can flow and solidify in response to localized intrusion of wheels, limbs, and bodies. While the development of airplanes and submarines is aided by understanding of hydrodynamics, fundamental theory does not yet exist to describe the complex interactions of locomotors with GM. In this pap...

september 2014 • Ieee rObOtICs & AUtOmAtION mAGAZINe • 1070-9932/14©2014Ieee T his article presents the results of a human subject experiment aimed at answering the question, “can increased muscle force variability in low force levels explain increased variability or intermittency of slow movements?” To address this research question, we conducted an experiment with eight subjects, which involv...

The flagellar force generated by a hyperactivated monkey spermatozoon was evaluated using the resistive force theory applied to the activated (nonhyperactivated) and hyperactivated flagellar waves that were obtained using high-speed video microscopy and digital image processing in order to clarify the mechanism of sperm penetration through the zona pellucida. No difference in the maximum propul...

Keywords: Micro-swimming Micro-flows Resistive force theory Hydrodynamic interaction Bio-inspired robots Surrogate models a b s t r a c t Research on micro-swimming robots without tether is growing fast owing to their potential impact on minimally invasive medical procedures. Candidate propulsion mechanisms of robots are vastly based on microorganisms with rotating helical tails. For design of ...

In basal apparatus isolated fromC. reinhardtii, if the frequency mismatch is high, mechanical or hydrodynamic coupling cannot synchronize them.

Equations describing the motion of the dinoflagellate Prorocentrum minimum, which has both a longitudinal and a transverse flagellum, were formulated and examined using numerical calculations based on hydrodynamic resistive force theory. The calculations revealed that each flagellum has its own function in cell locomotion. The transverse flagellum works as a propelling device that provides the ...