Laser investigations on the role of cholesterol in some liquid crystal biological membrane models

2002 ◽  
Author(s):  
Mihaela A. Ghelmez ◽  
Elena Slavnicu ◽  
Bogdan Dumitru ◽  
Andreea-Rodica P. Sterian ◽  
C. Molnar ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Biological Membrane ◽  
Membrane Models

scholarly journals The role of curvature in silica mesoporous crystals

2012 ◽  
Vol 2 (5) ◽  
pp. 634-644 ◽  
Author(s):  
Keiichi Miyasaka ◽  
Alfonso Garcia Bennett ◽  
Lu Han ◽  
Yu Han ◽  
Changhong Xiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Liquid Crystal ◽  
Biological Membrane ◽  
Porous Silica ◽  
Mesoporous Structure ◽  
Synthesis Conditions ◽  
Interface Curvature ◽  
Silica Wall

Silica mesoporous crystals (SMCs) offer a unique opportunity to study micellar mesophases. Replication of non-equilibrium mesophases into porous silica structures allows the characterization of surfactant phases under a variety of chemical and physical perturbations, through methods not typically accessible to liquid crystal chemists. A poignant example is the use of electron microscopy and crystallography, as discussed herein, for the purpose of determining the fundamental role of amphiphile curvature, namely mean curvature and Gaussian curvature, which have been extensively studied in various fields such as polymer, liquid crystal, biological membrane, etc. The present work aims to highlight some current studies devoted to the interface curvature on SMCs, in which electron microscopy and electron crystallography (EC) are used to understand the geometry of silica wall surface in bicontinuous and cage-type mesostructures through the investigation of electrostatic potential maps. Additionally, we show that by altering the synthesis conditions during the preparation of SMCs, it is possible to isolate particles during micellar mesophase transformations in the cubic bicontinuous system, allowing us to view and study epitaxial relations under the specific synthesis conditions. By studying the relationship between mesoporous structure, interface curvature and micellar mesophases using electron microscopy and EC, we hope to bring new insights into the formation mechanism of these unique materials but also contribute a new way of understanding periodic liquid crystal systems.

scholarly journals Molecular Dynamics of Chloroplast Membranes Isolated from Wild-Type Barley and a Brassinosteroid-Deficient Mutant Acclimated to Low and High Temperatures

Biomolecules ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 27
Author(s):  
Iwona Sadura ◽  
Dariusz Latowski ◽  
Jana Oklestkova ◽  
Damian Gruszka ◽  
Marek Chyc ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Temperature Stress ◽  
High Temperatures ◽  
Biological Membrane ◽  
Hydrophobic Core ◽  
Wild Type ◽  
Chloroplast Membranes ◽  
Paramagnetic Resonance ◽  
Photosynthetic Membranes

Plants have developed various acclimation strategies in order to counteract the negative effects of abiotic stresses (including temperature stress), and biological membranes are important elements in these strategies. Brassinosteroids (BR) are plant steroid hormones that regulate plant growth and development and modulate their reaction against many environmental stresses including temperature stress, but their role in modifying the properties of the biological membrane is poorly known. In this paper, we characterise the molecular dynamics of chloroplast membranes that had been isolated from wild-type and a BR-deficient barley mutant that had been acclimated to low and high temperatures in order to enrich the knowledge about the role of BR as regulators of the dynamics of the photosynthetic membranes. The molecular dynamics of the membranes was investigated using electron paramagnetic resonance (EPR) spectroscopy in both a hydrophilic and hydrophobic area of the membranes. The content of BR was determined, and other important membrane components that affect their molecular dynamics such as chlorophylls, carotenoids and fatty acids in these membranes were also determined. The chloroplast membranes of the BR-mutant had a higher degree of rigidification than the membranes of the wild type. In the hydrophilic area, the most visible differences were observed in plants that had been grown at 20 °C, whereas in the hydrophobic core, they were visible at both 20 and 5 °C. There were no differences in the molecular dynamics of the studied membranes in the chloroplast membranes that had been isolated from plants that had been grown at 27 °C. The role of BR in regulating the molecular dynamics of the photosynthetic membranes will be discussed against the background of an analysis of the photosynthetic pigments and fatty acid composition in the chloroplasts.

Self-Assembly of PEG-b-Liquid Crystal Polymer:  The Role of Smectic Order in the Formation of Nanofibers

2007 ◽  
Vol 40 (16) ◽  
pp. 5625-5627 ◽  
Author(s):  
Rafael Piñol ◽  
Lin Jia ◽  
Francesca Gubellini ◽  
Daniel Lévy ◽  
Pierre-Antoine Albouy ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Self Assembly ◽  
Liquid Crystal Polymer ◽  
Crystal Polymer

The Role of Two-Dimensional Roughness Element in the Laminar-Turbulent Process in the Favorable Pressure Gradient of the Swept Wing

2014 ◽  
Vol 9 (4) ◽  
pp. 65-73
Author(s):  
Stepan Tolkachev ◽  
Valeria Kaprilevskaya ◽  
Viktor Kozlov
Keyword(s):  
Liquid Crystal ◽  
Roughness Element ◽  
Frequency Interval ◽  
Two Dimensional ◽  
Swept Wing ◽  
Liquid Crystal Thermography ◽  
Roughness Elements ◽  
Favorable Pressure Gradient ◽  
Turbulent Process

In the article using a liquid crystal thermography investigated the development of stationary and secondary disturbances, which were excited by cylindrical and two-dimensional roughness elements. It was shown, that two-dimensional roughness element has a destabilizing effect on disturbances, induced by cylindrical roughness element. Also the twodimensional roughness element is able to excite the stationary structures, and then the secondary disturbances the frequency interval of which is lower than in the case of stationary vortices excitation by cylindrical roughness element

Liquid crystal dimers and the twist-bend nematic phase: On the role of spacers and terminal alkyl chains

2020 ◽  
Vol 320 ◽  
pp. 114391 ◽  
Author(s):  
Ewan Forsyth ◽  
Daniel A. Paterson ◽  
Ewan Cruickshank ◽  
Grant J. Strachan ◽  
Ewa Gorecka ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Nematic Phase ◽  
Alkyl Chains

Theoretical rationalisation of the photophysics of a TICT excited state of cinnamoyl–coumarin derivatives in homogeneous and biological membrane models

2018 ◽  
Vol 20 (43) ◽  
pp. 27621-27629 ◽  
Author(s):  
Daniel Zúñiga-Núñez ◽  
Ricardo A. Zamora ◽  
Pablo Barrias ◽  
Cristian Tirapegui ◽  
Horacio Poblete ◽  
...  
Keyword(s):  
Excited State ◽  
Potential Energy ◽  
Structural Dynamics ◽  
Biological Membrane ◽  
Coumarin Derivatives ◽  
Energy Barriers ◽  
Membrane Models

Analysis of the potential energy barriers and structural dynamics of a new TICT-probe for monitoring biological environments.

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