scholarly journals Architectural Organization of Dinoflagellate Liquid Crystalline Chromosomes

2019 ◽  
Vol 7 (2) ◽  
pp. 27 ◽  
Author(s):  
Joseph Wong
Keyword(s):  
Soft Matter ◽  
Liquid Crystalline ◽  
Inner Core ◽  
Dynamic Equilibrium ◽  
Divalent Cations ◽  
Architectural Organization ◽  
Dna Density ◽  
Matter Phase ◽  
Order Structures ◽  
Architectural Protein

Dinoflagellates have some of the largest genome sizes, but lack architectural nucleosomes. Their liquid crystalline chromosomes (LCCs) are the only non-architectural protein-mediated chromosome packaging systems, having high degrees of DNA superhelicity, liquid crystalline condensation and high levels of chromosomal divalent cations. Recent observations on the reversible decompaction–recompaction of higher-order structures implicated that LCCs are composed of superhelical modules (SPMs) comprising highly supercoiled DNA. Orientated polarizing light photomicrography suggested the presence of three compartments with different packaging DNA density in LCCs. Recent and previous biophysical data suggest that LCCs are composed of: (a) the highly birefringent inner core compartment (i) with a high-density columnar-hexagonal mesophase (CH-m); (b) the lower-density core surface compartment (ii.1) consisting of a spiraling chromonema; (c) the birefringent-negative periphery compartment (ii.2) comprising peripheral chromosomal loops. C(ii.1) and C(ii.2) are in dynamic equilibrium, and can merge into a single compartment during dinomitosis, regulated through multiphasic reversible soft-matter phase transitions.

INHOMOGENEOUS LARGE DEFORMATION KINETICS OF POLYMERIC GELS

2013 ◽  
Vol 05 (01) ◽  
pp. 1350001 ◽  
Author(s):  
WILLIAM TOH ◽  
ZISHUN LIU ◽  
TENG YONG NG ◽  
WEI HONG
Keyword(s):  
Large Deformation ◽  
Soft Matter ◽  
Inner Core ◽  
Kinetic Studies ◽  
Fe Model ◽  
One Dimensional ◽  
Simplified Approach ◽  
Deformation Kinetics ◽  
Polymeric Gels ◽  
Kinetics Of

This work examines the dynamics of nonlinear large deformation of polymeric gels, and the kinetics of gel deformation is carried out through the coupling of existing hyperelastic theory for gels with kinetic laws for diffusion of small molecules. As finite element (FE) models for the transient swelling process is not available in commercial FE software, we develop a customized FE model/methodology which can be used to simulate the transient swelling process of hydrogels. The method is based on the similarity between diffusion and heat transfer laws by determining the equivalent thermal properties for gel kinetics. Several numerical examples are investigated to explore the capabilities of the present FE model, namely: a cube to study free swelling; one-dimensional constrained swelling; a rectangular block fixed to a rigid substrate to study swelling under external constraints; and a thin annulus fixed at the inner core to study buckling phenomena. The simulation results for the constrained block and one-dimensional constrained swelling are compared with available experimental data, and these comparisons show a good degree of similarity. In addition to this work providing a valuable tool to researchers for the study of gel kinetic deformation in the various applications of soft matter, we also hope to inspire works to adopt this simplified approach, in particular to kinetic studies of diffusion-driven mechanisms.

scholarly journals Ultrafast isomerization-induced cooperative motions to higher molecular orientation in smectic liquid-crystalline azobenzene molecules

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Masaki Hada ◽  
Daisuke Yamaguchi ◽  
Tadahiko Ishikawa ◽  
Takayoshi Sawa ◽  
Kenji Tsuruta ◽  
...  
Keyword(s):  
Molecular Orientation ◽  
Soft Matter ◽  
Liquid Crystalline ◽  
Laser Polarization ◽  
Time Resolved ◽  
Cooperative Motion ◽  
Subsequent Response ◽  
Molecular Dynamics Calculations ◽  
Polarization Axis ◽  
Linearly Polarized

Abstract The photoisomerization of molecules is widely used to control the structure of soft matter in both natural and synthetic systems. However, the structural dynamics of the molecules during isomerization and their subsequent response are difficult to elucidate due to their complex and ultrafast nature. Herein, we describe the ultrafast formation of higher-orientation of liquid-crystalline (LC) azobenzene molecules via linearly polarized ultraviolet light (UV) using ultrafast time-resolved electron diffraction. The ultrafast orientation is caused by the trans-to-cis isomerization of the azobenzene molecules. Our observations are consistent with simplified molecular dynamics calculations that revealed that the molecules are aligned with the laser polarization axis by their cooperative motion after photoisomerization. This insight advances the fundamental chemistry of photoresponsive molecules in soft matter as well as their ultrafast photomechanical applications.

The Triangular Cylinder Phase:  A New Mode of Self-Assembly in Liquid-Crystalline Soft Matter

2007 ◽  
Vol 129 (31) ◽  
pp. 9578-9579 ◽  
Author(s):  
Feng Liu ◽  
Bin Chen ◽  
Ute Baumeister ◽  
Xiangbing Zeng ◽  
Goran Ungar ◽  
...  
Keyword(s):  
Self Assembly ◽  
Soft Matter ◽  
Liquid Crystalline

scholarly journals George William Gray CBE MRIA FRSE. 4 September 1926 — 12 May 2013

2016 ◽  
Vol 62 ◽  
pp. 187-211
Author(s):  
John W. Goodby ◽  
Peter Raynes
Keyword(s):  
British Empire ◽  
Royal Society ◽  
Soft Matter ◽  
Liquid Crystalline ◽  
Three Dimensional ◽  
Liquid Crystal Displays ◽  
Honorary Member ◽  
Flat Panel Displays ◽  
Electronic Displays ◽  
Societal Changes

George Gray was a renowned British materials chemist, internationally distinguished for his research into liquid crystals and their applications in flat-panel displays. His seminal invention of the liquid-crystalline cyanobiphenyls underpinned the creation of the modern electronic displays industry, which began with digital watches and has continued through to smart and three-dimensional televisions. There are now more liquid crystal displays in the world than people, and these devices have engendered societal changes through social networking on the Internet. His ability to design, synthesize and utilize self-organizing materials across the various disciplines of science showed that he was a supreme molecular engineer. For his contributions to soft-matter and related advanced technologies he was made a Commander of the British Empire, Kyoto Prize laureate, Fellow of the Royal Society, Fellow of the Royal Society of Edinburgh and Honorary Member of the Royal Irish Academy.

scholarly journals Introduction to Colloidal and Microfluidic Nematic Microstructures

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 956
Author(s):  
Simon Čopar ◽  
Miha Ravnik ◽  
Slobodan Žumer
Keyword(s):  
Soft Matter ◽  
Liquid Crystalline ◽  
Colloidal Particles ◽  
Topological Defects ◽  
Crystalline Materials ◽  
Inherent Anisotropy ◽  
Metastable Structures ◽  
Liquid Crystalline Materials ◽  
Mesoscopic Theory

In this brief review, we give an introduction to selected colloidal and microfluidic nematic microstructures, as enabled by the inherent anisotropy and microscopic orientational ordering in complex liquid crystalline materials. We give a brief overview of the mesoscopic theory, for equilibrium and dynamics, of nematic fluids, that provides the framework for understanding, characterization, and even prediction of such microstructures, with particular comment also on the role of topology and topological defects. Three types of nematic microstructures are highlighted: stable or metastable structures in nematic colloids based on spherical colloidal particles, stationary nematic microfluidic structures, and ferromagnetic liquid crystal structures based on magnetic colloidal particles. Finally, this paper is in honor of Noel A. Clark, as one of the world pioneers that helped to shape this field of complex and functional soft matter, contributing at different levels to works of various groups worldwide, including ours.

The POLICRYPS liquid-crystalline structure for optical applications

2018 ◽  
Vol 7 (5) ◽  
pp. 273-289
Author(s):  
Roberto Caputo ◽  
Antonio De Luca ◽  
Giuseppe Strangi ◽  
Roberto Bartolino ◽  
Cesare Umeton ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Soft Matter ◽  
Liquid Crystalline ◽  
High Efficiency ◽  
Light Polarization ◽  
Polymer Liquid ◽  
Polarized Beams ◽  
Optical Applications ◽  
Polar Symmetry ◽  
Polymer Liquid Crystal

Abstract We present a review of polymer-liquid crystal-based devices for optical applications. Starting from a particular fabrication technique, which enables to obtain the POLICRYPS (POlymer LIquid CRYstal Polymer Slices) structure, we illustrate different realizations, along with their working principle and main features and performances. The name POLICRYPS indicates a structure made of parallel slices of pure polymeric material alternated to films of well-aligned nematic liquid crystal (NLC), with a spatial periodicity that can be settled in the range 0.2÷15 μm. Suitably designed samples can be utilized as optical devices with a high efficiency, which can be switched on and off both by applying an electric field of a few V/μm or by irradiating samples with a suitable light beam. In different geometries, POLICRYPS can be specialized to operate as switchable diffraction grating, switchable optical phase modulator, switchable beam splitter, or tunable Bragg filter. The POLICRYPS framework can be also used as a soft matter template for aligning different types of LCs or to create an array of tunable microlasers. Finally, we present a POLICRYPS structure with a polar symmetry of the director alignment, which enables local shaping of light polarization, allowing to convert circularly polarized beams into cylindrical vector beams.

scholarly journals Rheological signatures in limit cycle behaviour of dilute, active, polar liquid crystalline polymers in steady shear

2014 ◽  
Vol 372 (2029) ◽  
pp. 20130362 ◽  
Author(s):  
M. Gregory Forest ◽  
Panon Phuworawong ◽  
Qi Wang ◽  
Ruhai Zhou
Keyword(s):  
Limit Cycles ◽  
Soft Matter ◽  
Liquid Crystalline ◽  
Numerical Study ◽  
Shear Thickening ◽  
Liquid Crystalline Polymers ◽  
Two Dimensional ◽  
Crystalline Polymers ◽  
Link Type ◽  
Linearized Stability

We consider the dilute regime of active suspensions of liquid crystalline polymers (LCPs), addressing issues motivated by our kinetic model and simulations in Forest et al. (Forest et al. 2013 Soft Matter 9 , 5207–5222 ( doi:10.1039/c3sm27736d )). In particular, we report unsteady two-dimensional heterogeneous flow-orientation attractors for pusher nanorod swimmers at dilute concentrations where passive LCP equilibria are isotropic. These numerical limit cycles are analogous to longwave (homogeneous) tumbling and kayaking limit cycles and two-dimensional heterogeneous unsteady attractors of passive LCPs in weak imposed shear, yet these states arise exclusively at semi-dilute concentrations where stable equilibria are nematic. The results in Forest et al. mentioned above compel two studies in the dilute regime that complement recent work of Saintillan & Shelley (Saintillan & Shelley 2013 C. R. Physique 14 , 497–517 ( doi:10.1016/j.crhy.2013.04.001 )): linearized stability analysis of the isotropic state for nanorod pushers and pullers; and an analytical–numerical study of weakly and strongly sheared active polar nanorod suspensions to capture how particle-scale activation affects shear rheology. We find that weakly sheared dilute puller versus pusher suspensions exhibit steady versus unsteady responses, shear thickening versus thinning and positive versus negative first normal stress differences. These results further establish how sheared dilute nanorod pusher suspensions exhibit many of the characteristic features of sheared semi-dilute passive nanorod suspensions.

scholarly journals Analysis of the Structure and Biosynthesis of the Lipopolysaccharide Core Oligosaccharide of Pseudomonas syringae pv. tomato DC3000

2021 ◽  
Vol 22 (6) ◽  
pp. 3250
Author(s):  
Alexander Kutschera ◽  
Ursula Schombel ◽  
Dominik Schwudke ◽  
Stefanie Ranf ◽  
Nicolas Gisch
Keyword(s):  
Pseudomonas Syringae ◽  
Species Complex ◽  
Inner Core ◽  
Divalent Cations ◽  
Membrane Integrity ◽  
Outer Core ◽  
Core Oligosaccharide ◽  
Structure Information ◽  
The Core ◽  
Genetic Components

Lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria, is important for bacterial viability in general and host–pathogen interactions in particular. Negative charges at its core oligosaccharide (core-OS) contribute to membrane integrity through bridging interactions with divalent cations. The molecular structure and synthesis of the core-OS have been resolved in various bacteria including the mammalian pathogen Pseudomonas aeruginosa. A few core-OS structures of plant-associated Pseudomonas strains have been solved to date, but the genetic components of the underlying biosynthesis remained unclear. We conducted a comparative genome analysis of the core-OS gene cluster in Pseudomonas syringae pv. tomato (Pst) DC3000, a widely used model pathogen in plant–microbe interactions, within the P. syringae species complex and to other plant-associated Pseudomonas strains. Our results suggest a genetic and structural conservation of the inner core-OS but variation in outer core-OS composition within the P. syringae species complex. Structural analysis of the core-OS of Pst DC3000 shows an uncommonly high phosphorylation and presence of an O-acetylated sugar. Finally, we combined the results of our genomic survey with available structure information to estimate the core-OS composition of other Pseudomonas species.

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