scholarly journals Kinetic instability, symmetry breaking and role of geometric constraints on the upper bounds of disorder in two dimensional packings

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Raj Kishore ◽  
Shreeja Das ◽  
Zohar Nussinov ◽  
Kisor K. Sahu
Keyword(s):  
Symmetry Breaking ◽  
Upper Bounds ◽  
Geometric Constraints ◽  
Two Dimensional ◽  
Kinetic Instability

scholarly journals Synchronization of flexible sheets

2011 ◽  
Vol 674 ◽  
pp. 163-173 ◽  
Author(s):  
GWYNN J. ELFRING ◽  
ERIC LAUGA
Keyword(s):  
Energy Dissipation ◽  
Symmetry Breaking ◽  
Crucial Role ◽  
Physical Mechanism ◽  
Fluid Layer ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Close Proximity ◽  
Two Dimensional Model

When swimming in close proximity, some microorganisms such as spermatozoa synchronize their flagella. Previous work on swimming sheets showed that such synchronization requires a geometrical asymmetry in the flagellar waveforms. Here we inquire about a physical mechanism responsible for such symmetry breaking in nature. Using a two-dimensional model, we demonstrate that flexible sheets with symmetric internal forcing deform when interacting with each other via a thin fluid layer in such a way as to systematically break the overall waveform symmetry, thereby always evolving to an in-phase conformation where energy dissipation is minimized. This dynamics is shown to be mathematically equivalent to that obtained for prescribed waveforms in viscoelastic fluids, emphasizing the crucial role of elasticity in symmetry breaking and synchronization.

Centrosome Aurora A gradient ensures single polarity axis in C. elegans embryos

2020 ◽  
Vol 48 (3) ◽  
pp. 1243-1253 ◽  
Author(s):  
Sukriti Kapoor ◽  
Sachin Kotak
Keyword(s):  
Symmetry Breaking ◽  
Cell Fate ◽  
Cell Cortex ◽  
Axis Formation ◽  
Aurora A Kinase ◽  
Aurora A ◽  
C Elegans ◽  
Cell Embryo ◽  
Polarity Establishment

Cellular asymmetries are vital for generating cell fate diversity during development and in stem cells. In the newly fertilized Caenorhabditis elegans embryo, centrosomes are responsible for polarity establishment, i.e. anterior–posterior body axis formation. The signal for polarity originates from the centrosomes and is transmitted to the cell cortex, where it disassembles the actomyosin network. This event leads to symmetry breaking and the establishment of distinct domains of evolutionarily conserved PAR proteins. However, the identity of an essential component that localizes to the centrosomes and promotes symmetry breaking was unknown. Recent work has uncovered that the loss of Aurora A kinase (AIR-1 in C. elegans and hereafter referred to as Aurora A) in the one-cell embryo disrupts stereotypical actomyosin-based cortical flows that occur at the time of polarity establishment. This misregulation of actomyosin flow dynamics results in the occurrence of two polarity axes. Notably, the role of Aurora A in ensuring a single polarity axis is independent of its well-established function in centrosome maturation. The mechanism by which Aurora A directs symmetry breaking is likely through direct regulation of Rho-dependent contractility. In this mini-review, we will discuss the unconventional role of Aurora A kinase in polarity establishment in C. elegans embryos and propose a refined model of centrosome-dependent symmetry breaking.

scholarly journals Role of fluctuations in the yielding transition of two-dimensional glasses

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Misaki Ozawa ◽  
Ludovic Berthier ◽  
Giulio Biroli ◽  
Gilles Tarjus
Keyword(s):  
Two Dimensional

scholarly journals Stability of Two-Dimensional Viscous Incompressible Flows under Three-Dimensional Perturbations and Inviscid Symmetry Breaking

2013 ◽  
Vol 45 (3) ◽  
pp. 1871-1885 ◽  
Author(s):  
C. Bardos ◽  
M. C. Lopes Filho ◽  
Dongjuan Niu ◽  
H. J. Nussenzveig Lopes ◽  
E. S. Titi
Keyword(s):  
Symmetry Breaking ◽  
Incompressible Flows ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Viscous Incompressible Flows
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