scholarly journals Triggered disassembly and reassembly of actin networks induces rigidity phase transitions

Soft Matter ◽  
2019 ◽  
Vol 15 (6) ◽  
pp. 1335-1344 ◽  
Author(s):  
Bekele J. Gurmessa ◽  
Nicholas Bitten ◽  
Dan T. Nguyen ◽  
Omar A. Saleh ◽  
Jennifer L. Ross ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Phase Transitions ◽  
Optical Tweezers ◽  
Actin Filaments ◽  
Time Dependent ◽  
Time Resolved ◽  
Actin Networks ◽  
Diffusion Controlled

We couple time-resolved optical tweezers microrheology with diffusion-controlled microfluidics and mathematical modeling to elucidate the time-dependent mechanics of entangled and crosslinked actin networks during dynamic depolymerization and repolymerization of actin filaments.

BIOMIMETIC MODELS OF THE ACTIN CORTEX

2009 ◽  
Vol 04 (01n02) ◽  
pp. 17-32 ◽  
Author(s):  
TAMÁS HARASZTI ◽  
SIMON SCHULZ ◽  
KAI UHRIG ◽  
RAINER KURRE ◽  
WOUTER ROOS ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Actin Filaments ◽  
Network Formation ◽  
The Other ◽  
Actin Networks ◽  
Biomimetic Models ◽  
Actin Cortex ◽  
Crosslinking Process ◽  
Holographic Optical Tweezers ◽  
Polystyrene Microparticles

The cytoskeleton is an actively regulated complex network in the cell. One of the most researched components is actin. In our work we developed and tested two microfluidic systems both being applicable to construct quasi 2-dimensional biomimetic actin networks. The first system uses polydimethylsiloxane micropillars, the other polystyrene microparticles held by holographic optical tweezers as anchoring points. Our devices provide actin networks with mesh sizes from a few micrometers up to the order of 10 micrometers. Qualitative analysis shows similar network formation in both systems. Crosslinking was tested using filamin, α-actinin, Ca and Mg ions. The crosslinking process is characterized by a zipping like event, which is limited only by the high stretching modulus of the actin filaments.

Multiple phase transitions investigated by high-speed TEM

1990 ◽  
Vol 48 (4) ◽  
pp. 550-551
Author(s):  
Oleg Bostanjoglo ◽  
Peter Thomsen-Schmidt
Keyword(s):  
Phase Transitions ◽  
High Speed ◽  
Short Exposure ◽  
Semiconductor Film ◽  
Time Resolved ◽  
Short Exposure Time ◽  
Multiple Phase ◽  
Model Substance ◽  
History Of ◽  
Electron Image

Thin GexTe1-x (x = 0.15-0.8) were studied as a model substance of a composite semiconductor film, in addition being of interest for optical storage material. Two complementary modes of time-resolved TEM were used to trace the phase transitions, induced by an attached Q-switched (50 ns FWHM) and frequency doubled (532 nm) Nd:YAG laser. The laser radiation was focused onto the specimen within the TEM to a 20 μm spot (FWHM). Discrete intermediate states were visualized by short-exposure time doubleframe imaging /1,2/. The full history of a transformation was gained by tracking the electron image intensity with photomultiplier and storage oscilloscopes (space/time resolution 100 nm/3 ns) /3/. In order to avoid radiation damage by the probing electron beam to detector and specimen, the beam is pulsed in this continuous mode of time-resolved TEM,too.Short events ( <2 μs) are followed by illuminating with an extended single electron pulse (fig. 1c)

scholarly journals Ground- and excited-state characteristics in photovoltaic polymer N2200

RSC Advances ◽  
2021 ◽  
Author(s):  
Guanzhao Wen ◽  
Xianshao Zou ◽  
Rong Hu ◽  
Jun Peng ◽  
Zhifeng Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Steady State ◽  
Excited States ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Time Dependent ◽  
Functional Theory ◽  
Time Resolved ◽  
Dependent Density

Ground- and excited-states properties of N2200 have been studied by steady-state and time-resolved spectroscopies as well as time-dependent density functional theory calculations.

Geometric effect on the vortex configuration and motion in mesoscopic superconducting cylinders

2015 ◽  
Vol 29 (03) ◽  
pp. 1550009 ◽  
Author(s):  
Shan-Shan Wang ◽  
Guo-Qiao Zha
Keyword(s):  
Phase Transitions ◽  
Vortex Dynamics ◽  
Axial Symmetry ◽  
Time Dependent ◽  
Vortex Matter ◽  
Ginzburg Landau ◽  
Geometric Effect ◽  
Multiply Connected ◽  
Vortex States ◽  
Ginzburg Landau Equations

Based on the time-dependent Ginzburg–Landau equations, we study numerically the vortex configuration and motion in mesoscopic superconducting cylinders. We find that the effects of the geometric symmetry of the system and the noncircular multiply-connected boundaries can significantly influence the steady vortex states and the vortex matter moving. For the square cylindrical loops, the vortices can enter the superconducting region in multiples of 2 and the vortex configuration exhibits the axial symmetry along the square diagonal. Moreover, the vortex dynamics behavior exhibits more complications due to the existed centered hole, which can lead to the vortex entering from different edges and exiting into the hole at the phase transitions.

Time-Resolved Studies Of Phase Transitions At Semiconductor Surfaces

1988 ◽  
Author(s):  
H. W. Tom ◽  
G. D. Aumiller ◽  
C. H. Brito-Cruz
Keyword(s):  
Phase Transitions ◽  
Semiconductor Surfaces ◽  
Time Resolved

In-Situ, Time Resolved, Kinetics of Reactions in Co-Ge thin Films

1991 ◽  
Vol 237 ◽  
Author(s):  
R. M. Walser ◽  
Byung-Hak Lee ◽  
Alaka Valanju ◽  
Winston Win ◽  
M. F. Becker
Keyword(s):  
Depth Profiling ◽  
Laser Interferometry ◽  
Semiconductor Interface ◽  
Time Resolved ◽  
Interface Reactions ◽  
Valuable Adjunct ◽  
Diffusion Controlled ◽  
Sputter Deposited ◽  
Time Required

ABSTRACTWe report the first kinetic study of metal-semiconductor interface reactions using in-situ, time resolved, laser interferometry. Diffusion couples with Co/Ge thicknesses of 1500 Å/1500 Å were sputter deposited on silicon wafers, and vacuum-annealed at temperatures between 300°C-400°C. Under these conditions polycrystalline CoGe was expected to form [1]. Real time laser (HeNe 6328 Å) interferograms for each anneal were recorded in-situ. These data were supplemented by information from AES and X-ray.For temperatures below 400°C the diffusion controlled formation of CoGe was observed. The composition was confirmed by Auger depth profiling that showed uniform Co and Ge concentrations when the reaction went to completion. The well defined interferences fringes were formed by the dissolution of amorphous Ge. The activation energy = 1.6 eV for the formation of CoGe were determined with precision from the temperature dependence of the time required to anneal the fixed λ/4 distance between adjacent minima and maxima of the interferogram. We discuss the evidence for formation of an intermediate Co-rich compound following the initial diffusion of Co into Ge. The results of these experiments indicate that optical interferometry will be a valuable adjunct to other techniques used to study metal-semiconductor interface reactions.

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