BEGIN:VCALENDAR VERSION:2.0 PRODID:Data::ICal 0.22 BEGIN:VEVENT DESCRIPTION:Aleksander Donev\, New York University\n\n
E
very animal cell is filled with a cytoskeleton\, a dynamic gel made of ine
xtensible filaments / bio-polymers\, such as microtubules\, actin filament
s\, and intermediate filaments\, all suspended in a viscous fluid. Similar
suspensions of elastic filaments or polymers are widely used in materials
processing. Numerical simulation of such gels is challenging because the
filament aspect ratios are very large.
\n
\nWe have recently dev
eloped new methods for rapidly computing the dynamics of non-Brownian and
Brownian inextensible slender filaments in periodically-sheared Stokes flo
w [1\,2\,4]. We apply our formulation to a permanently1 and dynamically cr
oss-linked actin mesh3 in a background oscillatory shear flow. We find tha
t nonlocal hydrodynamics can change the visco-elastic moduli by as much as
40% at certain frequencies\, especially in partially bundled networks [3\
,4].
\n
\nI will focus on accounting for bending thermal fluctua
tions of the filaments by first establishing a mathematical formulation an
d numerical methods for simulating the dynamics of stiff but not rigid Bro
wnian fibers in Stokes flow [4]. I will emphasize open questions for the c
ommunity such as whether there is a continuum limit of the Brownian contri
bution to the stress tensor from the filaments.
\n
\nReferences:
\n
\n1. O. Maxian et al\, Integral-based spectral method for in
extensible slender fibers in Stokes flow\,. Phys. Rev. Fluids\, 6:014102\,
2021
\n2. O. Maxian et al\,. Hydrodynamics of a twisting\, bending\,
inextensible fiber in Stokes flow\, Phys. Rev. Fluids\, 7:074101\, 2022\n3. O. Maxian et al\, Interplay between Brownian motion and cross-lin
king controls bundling dynamics in actin networks\, Biophysical J.\, 121:1
230\\u20131245\, 2022.
\n4. O. Maxian et al.\, Bending fluctuations i
n semiflexible\, inextensible\, slender filaments in Stokes flow: towards
a spectral discretization\, ArXiv:2301.11123\, to appear in J. Chem. Phys.
\, 2023.