scholarly journals Computer simulation of soft matter at the growth front of a hard-matter phase: incorporation of polymers, formation of transient pits and growth arrest

2012 ◽  
Vol 159 ◽  
pp. 263 ◽  
Author(s):  
Richard P. Sear
Keyword(s):  
Computer Simulation ◽  
Soft Matter ◽  
Growth Arrest ◽  
Growth Front ◽  
Matter Phase

Expression of senescence in Neurospora intermedia

1986 ◽  
Vol 28 (3) ◽  
pp. 459-467 ◽  
Author(s):  
A. J. F. Griffiths ◽  
S. Kraus ◽  
H. Bertrand
Keyword(s):  
Mitochondrial Dna ◽  
Genetic Factors ◽  
Growth Arrest ◽  
Growth Front ◽  
Continuous Growth ◽  
Quiescent Cells ◽  
Neurospora Intermedia ◽  
Aerial Hyphae ◽  
Similar Basis ◽  
Transfer Interval

Kalilo cytoplasms of Neurospora intermedia have been shown to express senescence in two ways. First, by the previously reported way of death in a subculture series, and second, as reported here, by growth cessation in a 50-cm race tube. Only those cultures that are sufficiently far advanced in the development of senescence will stop growth in the length of a race tube. Resumption of growth occurs in most cases of growth arrest in race tubes. Although in subculture series growth resumption is rare, there is probably a similar basis: mitochondrial DNA (mtDNA) studies on one such case showed that growth resumption is associated with a resurgence of normal mtDNA and a decline of abnormal genomes. When senescent cultures in race tubes were sampled by removing mycelial cores, longer grown cultures were shown to be able to support less growth than younger cultures of the same genotype, and the growth front was generally able to support less growth than other regions. Therefore senescence in both transfer series and in race tubes involves the accumulation of genetic factors unable to suppport continuous growth. The expression of senescence is considered to be more efficient in subculture series than in race tubes. In such series, conidia or aerial hyphae work equally well as transfer inocula, but 1-mm hyphal tips cut from growing mycelium do not promote senescence when used as inocula. Furthermore, varying the transfer interval does not affect senescence. It is concluded that there is some feature of the development or germination of quiescent cells that enhances the expression of senescence in Neurospora.Key words: Neurospora, senescence, mitochondria, growth.

Bi-continuous orthorhombic soft matter phase made of polycatenar molecules

Soft Matter ◽  
2020 ◽  
Vol 16 (16) ◽  
pp. 3882-3885 ◽  
Author(s):  
Joanna Matraszek ◽  
Damian Pociecha ◽  
Nataša Vaupotič ◽  
Mirosław Salamończyk ◽  
Martin Vogrin ◽  
...  
Keyword(s):  
Intermediate State ◽  
Soft Matter ◽  
Columnar Phase ◽  
Double Gyroid ◽  
Matter Phase ◽  
Slight Deformation

A slight deformation of a double gyroid structure of a cubic Ia3̄d phase results in the formation of a phase with an orthorhombic Pcab symmetry. The phase seems to be an intermediate state towards a columnar phase made of helical pillars.

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.

Α Computer Simulation: Before or After the Instruction?: A Didactic Approach for Teaching the Process of Matter Phase Changes to Students

2006 ◽  
Vol 12 (8) ◽  
pp. 295-302 ◽  
Author(s):  
Psycharis Sarantos ◽  
Evi Makri-Botsari ◽  
Fotini Paraskeva
Keyword(s):  
Computer Simulation ◽  
Phase Changes ◽  
Matter Phase

Montmorillonite Dendrites

1974 ◽  
Vol 32 ◽  
pp. 454-455
Author(s):  
Necip Güven ◽  
Rodney W. Pease
Keyword(s):  
Crystal Growth ◽  
Growth Mechanism ◽  
Growth Front ◽  
Morphological Features ◽  
Dendritic Crystal ◽  
Crystal Growth Mechanism

Morphological features of montmorillonite aggregates in a large number of samples suggest that they may be formed by a dendritic crystal growth mechanism (i.e., tree-like growth by branching of a growth front).

Characterization of Modulated Structure Through Structure Images and their Computer Simulation

1990 ◽  
Vol 48 (1) ◽  
pp. 70-71
Author(s):  
Kiyomichi Nakai ◽  
Yusuke Isobe ◽  
Chiken Kinoshita ◽  
Kazutoshi Shinohara
Keyword(s):  
Computer Simulation ◽  
High Resolution ◽  
Spherical Aberration ◽  
High Resolution Electron Microscopy ◽  
Basic Mechanism ◽  
Objective Lens ◽  
Specimen Thickness ◽  
Transmitted Beam ◽  
Modulated Structure ◽  
Resolution Electron

Induced spinodal decomposition under electron irradiation in a Ni-Au alloy has been investigated with respect to its basic mechanism and confirmed to be caused by the relaxation of coherent strain associated with modulated structure. Modulation of white-dots on structure images of modulated structure due to high-resolution electron microscopy is reduced with irradiation. In this paper the atom arrangement of the modulated structure is confirmed with computer simulation on the structure images, and the relaxation of the coherent strain is concluded to be due to the reduction of phase-modulation.Structure images of three-dimensional modulated structure along <100> were taken with the JEM-4000EX high-resolution electron microscope at the HVEM Laboratory, Kyushu University. The transmitted beam and four 200 reflections with their satellites from the modulated structure in an fee Ni-30.0at%Au alloy under illumination of 400keV electrons were used for the structure images under a condition of the spherical aberration constant of the objective lens, Cs = 1mm, the divergence of the beam, α = 3 × 10-4 rad, underfocus, Δf ≃ -50nm and specimen thickness, t ≃ 15nm. The CIHRTEM code was used for the simulation of the structure image.

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