The Propulsion of Sea-Urchin Spermatozoa
J. Gray,G. J. Hancock +1 more
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Although the amplitude may change as a wave passes along the tail, the propulsive properties of the latter may be expected to be closely similar to those of a tail generating waves of the same average amplitude.Abstract:
1. The general theory of flagellar propulsion is discussed and an expression obtained whereby the propulsive speed of a spermatozoon can be expressed in terms of the amplitude, wave-length and frequency of the waves passing down the tail of a spermatozoon of Psammechinus miliaris . 2. The expression obtained is applicable to waves of relatively large amplitude, and allowance is made for the presence of an inert head. 3. The calculated propulsive speed is almost identical with that derived from observational data. Unless the head of a spermatozoon is very much larger than that of Psammechinus , its presence makes relatively little difference to the propulsive speed. Most of the energy of the cell is used up in overcoming the tangential drag of the tail. 4. Although the amplitude may change as a wave passes along the tail, the propulsive properties of the latter may be expected to be closely similar to those of a tail generating waves of the same average amplitude.read more
Citations
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The hydrodynamics of swimming microorganisms
Eric Lauga,Thomas R. Powers +1 more
TL;DR: The biophysical and mechanical principles of locomotion at the small scales relevant to cell swimming, tens of micrometers and below are reviewed, with emphasis on the simple physical picture and fundamental flow physics phenomena in this regime.
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Microscopic artificial swimmers
TL;DR: It is shown that a linear chain of colloidal magnetic particles linked by DNA and attached to a red blood cell can act as a flexible artificial flagellum, which induces a beating pattern that propels the structure, and that the external fields can be adjusted to control the velocity and the direction of motion.
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Physics of microswimmers--single particle motion and collective behavior: a review.
TL;DR: The physics of locomotion of biological and synthetic microswimmers, and the collective behavior of their assemblies, are reviewed and the hydrodynamic aspects of swimming are addressed.
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Physics of Microswimmers - Single Particle Motion and Collective Behavior
TL;DR: In this article, the authors review the physics of locomotion of biological and synthetic microswimmers, and the collective behavior of their assemblies, including synchronization and the concerted beating of flagella and cilia.
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Magnetic Helical Micromachines: Fabrication, Controlled Swimming, and Cargo Transport
Soichiro Tottori,Li Zhang,Famin Qiu,Krzysztof Krawczyk,Alfredo Franco-Obregón,Bradley J. Nelson +5 more
TL;DR: A simple and general fabrication method for helical swimming micromachines by direct laser writing and e-beam evaporation is demonstrated and the magnetic helical devices exhibit varying magnetic shape anisotropy, yet always generate corkscrew motion using a rotating magnetic field.
References
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Journal ArticleDOI
Analysis of the Swimming of Microscopic Organisms
TL;DR: In this article, it was shown that if the waves down neighbouring tails are in phase, very much less energy is dissipated in the fluid between them than when the waves are in opposite phase.
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The self-propulsion of microscopic organisms through liquids
TL;DR: In this article, it is shown that the propulsion of a single filament which forms itself into a single wave is very near to that of an infinite filament with the same wave motion, where the velocity field can be described in terms of singularities situated at the centre of the sphere.
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The Action of Waving Cylindrical Tails in Propelling Microscopic Organisms
TL;DR: In this article, a model of the tail of a spermatozoon is discussed from a hydrodynamical point of view. The tail is assumed to be a flexible cylinder which is distorted by waves of lateral displacement propagated along its length, the resulting stress and motion in the surrounding fluid is analyzed mathematically.
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The Movement of Sea-Urchin Spermatozoa
TL;DR: Evidence, is presented which supports the view that all regions of the tail are actively contractile although mechanical forces may affect the propagation of bending waves along the filament.