scholarly journals Flagellar synchronization through direct hydrodynamic interactions

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Douglas R Brumley ◽  
Kirsty Y Wan ◽  
Marco Polin ◽  
Raymond E Goldstein
Keyword(s):  
Time Series ◽  
Stochastic Processes ◽  
Spatial Dependence ◽  
High Speed ◽  
Hydrodynamic Interactions ◽  
Intrinsic Properties ◽  
High Speed Imaging ◽  
Volvox Carteri ◽  
Hydrodynamic Coupling ◽  
Analysis Of Time Series

Flows generated by ensembles of flagella are crucial to development, motility and sensing, but the mechanisms behind this striking coordination remain unclear. We present novel experiments in which two micropipette-held somatic cells of Volvox carteri, with distinct intrinsic beating frequencies, are studied by high-speed imaging as a function of their separation and orientation. Analysis of time series shows that the interflagellar coupling, constrained by lack of connections between cells to be hydrodynamical, exhibits a spatial dependence consistent with theory. At close spacings it produces robust synchrony for thousands of beats, while at increasing separations synchrony is degraded by stochastic processes. Manipulation of the relative flagellar orientation reveals in-phase and antiphase states, consistent with dynamical theories. Flagellar tracking with exquisite precision reveals waveform changes that result from hydrodynamic coupling. This study proves unequivocally that flagella coupled solely through a fluid can achieve robust synchrony despite differences in their intrinsic properties.

Holographic control and high-speed imaging for studies of hydrodynamic coupling on a micron scale

2011 ◽  
Author(s):  
Miles Padgett ◽  
Richard Bowman ◽  
Arran Curran ◽  
Roberto Di Leonardo ◽  
Maria Dienerowitz ◽  
...  
Keyword(s):  
High Speed ◽  
High Speed Imaging ◽  
Hydrodynamic Coupling

scholarly journals High-Speed Imaging Reveals the Bimodal Nature of Dense Core Vesicle Exocytosis and Jet Flow through the Fusion Pore

2021 ◽  
Author(s):  
Pengcheng Zhang ◽  
David Rumschitzki ◽  
Robert H Edwards
Keyword(s):  
High Speed ◽  
Secretory Vesicle ◽  
Fusion Pore ◽  
Dense Core Vesicle ◽  
Intrinsic Properties ◽  
High Speed Imaging ◽  
Stochastic Variation ◽  
Vesicle Exocytosis ◽  
Flow Through ◽  
Dual Imaging

During exocytosis, the fusion of secretory vesicle with plasma membrane forms a pore that regulates release of neurotransmitter and peptide. Osmotic forces contribute to exocytosis but release through the pore is thought to occur by diffusion. Heterogeneity of fusion pore behavior has also suggested stochastic variation in a common exocytic mechanism, implying a lack of biological control. Imaging at millisecond resolution to observe the first events in exocytosis, we find that fusion pore duration is bimodal rather than stochastic. Loss of calcium sensor synaptotagmin 7 increases the proportion of slow events without changing the intrinsic properties of either class, indicating the potential for independent regulation. In addition, dual imaging shows a delay in the entry of external dye relative to release that indicates discharge at high velocity rather than strictly by diffusion.

Analysis of time series from stochastic processes

2000 ◽  
Vol 62 (3) ◽  
pp. 3146-3155 ◽  
Author(s):  
Janez Gradišek ◽  
Silke Siegert ◽  
Rudolf Friedrich ◽  
Igor Grabec
Keyword(s):  
Time Series ◽  
Stochastic Processes ◽  
Analysis Of Time Series

Correlation in the heart rate data

1998 ◽  
Vol 2 ◽  
pp. 141-148
Author(s):  
J. Ulbikas ◽  
A. Čenys ◽  
D. Žemaitytė ◽  
G. Varoneckas
Keyword(s):  
Nonlinear Dynamics ◽  
Experimental Data ◽  
Heart Rate ◽  
Time Series ◽  
Cardiovascular Function ◽  
Statistical Properties ◽  
Rate Data ◽  
Heart Rate Data ◽  
Dynamical Nature ◽  
Analysis Of Time Series

Variety of methods of nonlinear dynamics have been used for possibility of an analysis of time series in experimental physiology. Dynamical nature of experimental data was checked using specific methods. Statistical properties of the heart rate have been investigated. Correlation between of cardiovascular function and statistical properties of both, heart rate and stroke volume, have been analyzed. Possibility to use a data from correlations in heart rate for monitoring of cardiovascular function was discussed.

Experimental Measurement of In-Plane Rolling Nonpneumatic Tire Vibrations Using High-Speed Imaging

2019 ◽  
Vol 47 (3) ◽  
pp. 196-210
Author(s):  
Meghashyam Panyam ◽  
Beshah Ayalew ◽  
Timothy Rhyne ◽  
Steve Cron ◽  
John Adcox
Keyword(s):  
High Speed ◽  
Image Correlation ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
High Speed Imaging ◽  
Correlation Algorithm ◽  
Mode Decomposition ◽  
Series Of Experiments ◽  
Plane Deformations ◽  
Dominant Frequencies

ABSTRACT This article presents a novel experimental technique for measuring in-plane deformations and vibration modes of a rotating nonpneumatic tire subjected to obstacle impacts. The tire was mounted on a modified quarter-car test rig, which was built around one of the drums of a 500-horse power chassis dynamometer at Clemson University's International Center for Automotive Research. A series of experiments were conducted using a high-speed camera to capture the event of the rotating tire coming into contact with a cleat attached to the surface of the drum. The resulting video was processed using a two-dimensional digital image correlation algorithm to obtain in-plane radial and tangential deformation fields of the tire. The dynamic mode decomposition algorithm was implemented on the deformation fields to extract the dominant frequencies that were excited in the tire upon contact with the cleat. It was observed that the deformations and the modal frequencies estimated using this method were within a reasonable range of expected values. In general, the results indicate that the method used in this study can be a useful tool in measuring in-plane deformations of rolling tires without the need for additional sensors and wiring.

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