# gst: steady, whirling, planar beating, and writhing transitions for active filaments.

FIG. 2. Images showing the steady, whirling, planar beating, and writhing states for active filaments

<< Biofilament-motor protein complexes are ubiquitous in biology and drive the transport of cargo vital for many fundamental life processes at the cellular level. As they move, motor proteins exert compressive forces on the filaments to which they are attached. If the filament is clamped or tethered in some way, this force leads to buckling and a subsequent range of dynamics. >>️

<< The transition between whirling and beating has not yet been explored, and a characterization of the complex writhing behavior observed at higher forcing has not been performed. Furthermore, previous studies have focused on how the whirling, beating, or writhing vary with the follower force, leaving the dependence of the emergent state on the filament aspect ratio, a key parameter related to the balance of the viscous and elastic forces, largely unexplored. >>

AA << utilize techniques from computational dynamical systems to determine and characterize these bifurcations. (They) track emerging time-periodic branches and identify quasiperiodic states (..) investigate the effect of filament slenderness on the bifurcations and, in doing so, present a comprehensive overview of the dynamics which emerge in the follower force model. >>

️

Bethany Clarke, Yongyun Hwang, Eric E. Keaveny. Bifurcations and nonlinear dynamics of the follower force model for active filaments. Phys. Rev. Fluids 9, 073101. Jul 15, 2024. 

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.9.073101

Also: transition, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, bifurcation, transition, active filaments, microtubules, steady, whirling, planar beating, writhing

# gst: self-buckling and self-writhing of semi-flexible Entities (among P. mirabilis)

<< Multi-flagellated microorganisms can buckle and writhe under their own activity as they swim through a viscous fluid. New equilibrium configurations and steady-state dynamics then emerge which depend on the organism's mechanical properties and on the oriented distribution of flagella along its surface. Modeling the cell body as a semi-flexible Kirchhoff rod and coupling the mechanics to a dynamically evolving flagellar orientation field, (AA) derive the Euler-Poincaré equations governing dynamics of the system, and rationalize experimental observations of buckling and writhing of elongated swarmer P. mirabilis cells. >>

<< A sequence of bifurcations is identified as the body is made more compliant, due to both buckling and torsional instabilities. The results suggest that swarmer cells invest no more resources in maintaining membrane integrity than is necessary to prevent self-buckling. >>

️

Wilson Lough, Douglas B. Weibel, et al. Self-buckling and self-writhing of semi-flexible microorganisms. arXiv: 2211.04381v1 [cond-mat.soft]. Nov 8, 2022. 

https://arxiv.org/abs/2211.04381

Also 

keyword 'swimming' in FonT

https://flashontrack.blogspot.com/search?q=swimming

Keywords: gst, motility, swarm, swarming, swarmer, swim, swimming, swimmer, buckling, writhing.