Theory and Simulation of Texture Transformations in Chiral Systems: Applications to Biological Fibrous Composites

2001 ◽  
Vol 709 ◽  
Author(s):  
Gino De Luca ◽  
Alejandro D. Rey
Keyword(s):  
Three Dimensional ◽  
Front Propagation ◽  
Fibrous Composites ◽  
Propagation Process ◽  
Chiral Nematic ◽  
New Information ◽  
Biological Structures ◽  
Planar Film ◽  
Chiral Systems ◽  
Gennes Theory

ABSTRACTNumerous studies [1-3] have shown that chiral biological structures share common properties with liquids crystals, in particular a tendency to assemble in three-dimensional lattices very similar to that of chiral nematics. Biological fibrous composites are usually found in planar (film) and cylindrical (fibber) twist geometries. In this work, the formation process of the planar twist architecture is numerically investigated using a mesoscopic model based on the Landau-de Gennes theory of chiral nematic liquid crystals. The simulations and visualizations of the computed textures provide new information on some of the principles that govern the formation of chiral biological structures. It is found that a defect-free planar twist architecture arises from a chiral front propagation process with a fully relaxed wake.

Lung morphometry: a new generation of tools and experiments for organ, tissue, cell, and molecular biology

1993 ◽  
Vol 265 (6) ◽  
pp. L521-L548 ◽  
Author(s):  
R. P. Bolender ◽  
D. M. Hyde ◽  
R. T. Dehoff
Keyword(s):  
Structural Information ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Biological Data ◽  
Theory And Practice ◽  
Tissue Cell ◽  
New Information ◽  
Organ Tissue ◽  
New Generation ◽  
Three Dimensional Space

Today all structural information of the lung can be quantified and interpreted in the three-dimensional space of real-world biology. Remarkable achievements in the theory and practice of biological stereology are creating a new generation of data suitable for constructing structural hierarchies. Such hierarchies serve to organize and link biological data, thereby providing a framework on which to build new information systems. In this review, we describe the new tools of quantitative morphology and show how they can be used to design new experiments for lung research.

scholarly journals Super-Resolution Label-free Volumetric Vibrational Imaging

2021 ◽  
Author(s):  
Chenxi Qian ◽  
Kun Miao ◽  
Li-En Lin ◽  
Xinhong Chen ◽  
Jiajun Du ◽  
...  
Keyword(s):  
High Resolution ◽  
Three Dimensional ◽  
Super Resolution ◽  
Label Free ◽  
Fluorescence Techniques ◽  
Biological Structures ◽  
Imaging Strategy ◽  
Endogenous Proteins ◽  
Low Efficiency ◽  
Protein Rich

Innovations in high-resolution optical imaging have allowed visualization of nanoscale biological structures and connections. However, super-resolution fluorescence techniques, including both optics-oriented and sample-expansion based, are limited in quantification and throughput especially in tissues from photobleaching or quenching of the fluorophores, and low-efficiency or non-uniform delivery of the probes. Here, we report a general sample-expansion vibrational imaging strategy, termed VISTA, for scalable label-free high-resolution interrogations of protein-rich biological structures with resolution down to 82 nm. VISTA achieves decent three-dimensional image quality through optimal retention of endogenous proteins, isotropic sample expansion, and deprivation of scattering lipids. Free from probe-labeling associated issues, VISTA offers unbiased and high-throughput tissue investigations. With correlative VISTA and immunofluorescence, we further validated the imaging specificity of VISTA and trained an image-segmentation model for label-free multi-component and volumetric prediction of nucleus, blood vessels, neuronal cells and dendrites in complex mouse brain tissues. VISTA could hence open new avenues for versatile biomedical studies.

Numerical modelling of twisted nematic devices

1983 ◽  
Vol 309 (1507) ◽  
pp. 203-216 ◽  
Keyword(s):  
Liquid Crystal ◽  
Electric Fields ◽  
Low Cost ◽  
Three Dimensional ◽  
Physical Parameters ◽  
Crystal Layer ◽  
Liquid Crystal Layer ◽  
Chiral Nematic ◽  
Twisted Nematic ◽  
Three Dimensional Simulations

Over most of each active region in nematic and chiral nematic twist cells the motion and configuration of the liquid crystal layer does not vary appreciably with position parallel to the surfaces. In such laminar regions the statics, dynamics and optics ot the cell can be accurately simulated at low cost on a computer of moderate size, given the appropriate physical parameters. Methods and recent advances in simulation of laminar regions are reviewed. Bistable twist cells are simulated for illustration. Important problems of stability and edge effects in the presence of electric fields await solution with two- or three-dimensional simulations.

scholarly journals Barriers to front propagation in laminar, three-dimensional fluid flows

2018 ◽  
Vol 97 (3) ◽  
Author(s):  
Minh Doan ◽  
J. J. Simons ◽  
Katherine Lilienthal ◽  
Tom Solomon ◽  
Kevin A. Mitchell
Keyword(s):  
Three Dimensional ◽  
Fluid Flows ◽  
Front Propagation

A newly discovered skull of the temnospondyl amphibian Dendrerpeton acadianum Owen

1987 ◽  
Vol 24 (4) ◽  
pp. 796-805 ◽  
Author(s):  
Stephen J. Godfrey ◽  
Anthony R. Fiorillo ◽  
Robert L. Carroll
Keyword(s):  
Inner Ear ◽  
Posterior Margin ◽  
Functional Relationship ◽  
Impedance Matching ◽  
Three Dimensional ◽  
Natural Position ◽  
Lower Jaw ◽  
New Information ◽  
Early Tetrapods ◽  
Supporting Element

A virtually complete three-dimensional skull of a subadult of the temnospondyl amphibian Dendrerpeton acadianum provides new information on the structure of the palate and lower jaw. The left stapes appears to lie in a natural position on the quadrate ramus of the pterygoid. The proportionately large otic ossicle probably precluded it from having acted as a transmitter of airborne vibrations from a tympanum to the inner ear. The use of the term "otic notch" should be restricted to amphibians or reptiles in which the embayment of the posterior margin of the cheek is accompanied by the presence of a slender rod-like stapes that could have functioned as part of an impedance matching system. In those species in which a notch is present but the stapes is a massive "supporting" element, the term "squamosal embayment" should be used, rather than "otic notch." The squamosal embayment in early tetrapods may have been inherited directly from their fish ancestors and had no functional relationship to hearing.

scholarly journals Radial symmetry on three-dimensional shells in the Landau–de Gennes theory

2016 ◽  
Vol 314 ◽  
pp. 18-34 ◽  
Author(s):  
Giacomo Canevari ◽  
Mythily Ramaswamy ◽  
Apala Majumdar
Keyword(s):  
Three Dimensional ◽  
Radial Symmetry ◽  
Gennes Theory
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