scholarly journals Kinetics of polymer looping with macromolecular crowding: effects of volume fraction and crowder size

Soft Matter ◽  
2015 ◽  
Vol 11 (3) ◽  
pp. 472-488 ◽  
Author(s):  
Jaeoh Shin ◽  
Andrey G. Cherstvy ◽  
Ralf Metzler
Keyword(s):  
Volume Fraction ◽  
Macromolecular Crowding ◽  
Crowding Effects ◽  
Kinetics Of

Depending on the size of crowding molecules and their volume fraction the looping rates of polymers are facilitated or impeded.

Cosolvent and crowding effects on the polymerization kinetics of actin

2015 ◽  
Vol 17 (13) ◽  
pp. 8330-8337 ◽  
Author(s):  
Christopher Rosin ◽  
Paul Hendrik Schummel ◽  
Roland Winter
Keyword(s):  
Macromolecular Crowding ◽  
Polymerization Kinetics ◽  
Lag Phase ◽  
Crowding Effects ◽  
Kinetics Of

Effects of cosolvents and macromolecular crowding agents on the G-to-F-transformation of actin are studied. Drastic and diverse changes in the lag phase and association rates of polymerizing actin are observed under different solvent conditions.

scholarly journals The kinetics of islet amyloid polypeptide phase separated system and hydrogel formation are critically influenced by macromolecular crowding

2021 ◽  
Author(s):  
Lior Pytowski ◽  
David Vaux ◽  
Létitia Jean
Keyword(s):  
Type Ii Diabetes ◽  
Volume Fraction ◽  
Biological Fluids ◽  
Islet Amyloid Polypeptide ◽  
Macromolecular Crowding ◽  
Type Ii ◽  
Amyloid Aggregation ◽  
Islet Amyloid ◽  
Kinetics Of

Many protein misfolding diseases (e.g. type II diabetes and Alzheimer’s disease) are characterised by amyloid deposition. Human islet amyloid polypeptide (hIAPP, involved in type II diabetes) spontaneously undergoes liquid-liquid phase separation (LLPS) and a kinetically complex hydrogelation, both catalysed by hydrophobic-hydrophilic interfaces (e.g. air-water interface and/or phospholipids-water interfaces). Gelation of hIAPP phase separated liquid droplets initiates amyloid aggregation and formation of clusters of interconnected aggregates, which grow and fuse to eventually percolate the whole system. Droplet maturation into irreversible hydrogels via amyloid aggregation is thought to be behind the pathology of several diseases. Biological fluids contain a high volume fraction of macromolecules, leading to macromolecular crowding. Despite crowding agent addition in in vitro studies playing a significant role in changing protein phase diagrams, the mechanism underlying enhanced LLPS, and the effect(s) on stages beyond LLPS remain poorly or not characterised.  We investigated the effect of macromolecular crowding and increased viscosity on the kinetics of hIAPP hydrogelation using rheology and the evolution of the system beyond LLPS by microscopy. We demonstrate that increased viscosity exacerbated the kinetic variability of hydrogelation and of the phase separated-aggregated system, whereas macromolecular crowding abolished heterogeneity. Increased viscosity also strengthened the gel meshwork and accelerated aggregate cluster fusion. In contrast, crowding either delayed cluster fusion onset (dextran) or promoted it (Ficoll). Our study highlights that an in vivo crowded environment would critically influence amyloid stages beyond LLPS and pathogenesis.

scholarly journals Continuous Cooling Transformation Behaviour and Bainite Transformation Kinetics of 23CrNi3Mo Carburised Steel

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 48
Author(s):  
Wenjun Song ◽  
Min Lei ◽  
Mingpan Wan ◽  
Chaowen Huang
Keyword(s):  
Phase Transformation ◽  
Volume Fraction ◽  
Austenite Formation ◽  
Steel Matrix ◽  
Transformation Kinetics ◽  
Bainite Transformation ◽  
Continuous Cooling ◽  
The Matrix ◽  
Dimensional Growth ◽  
Kinetics Of

In this study, the phase transformation behaviour of the carburised layer and the matrix of 23CrNi3Mo steel was comparatively investigated by constructing continuous cooling transformation (CCT) diagram, determining the volume fraction of retained austenite (RA) and plotting dilatometric curves. The results indicated that Austenite formation start temperature (Ac1) and Austenite formation finish temperature (Ac3) of the carburised layer decreased compared to the matrix, and the critical cooling rate (0.05 °C/s) of martensite transformation is significantly lower than that (0.8 °C/s) of the matrix. The main products of phase transformation in both the carburised layer and the matrix were martensite and bainite microstructures. Moreover, an increase in carbon content resulted in the formation of lamellar martensite in the carburised layer, whereas the martensite in the matrix was still lath. Furthermore, the volume fraction of RA in the carburised layer was higher than that in the matrix. Moreover, the bainite transformation kinetics of the 23CrNi3Mo steel matrix during the continuous cooling process indicated that the mian mechanism of bainite transformation of the 23CrNi3Mo steel matrix is two-dimensional growth and one-dimensional growth.

scholarly journals Macromolecular Crowding Effects on Reactions of TePixD (Tll0078)†

2010 ◽  
Vol 87 (3) ◽  
pp. 584-589 ◽  
Author(s):  
Tsuguyoshi Toyooka ◽  
Keisuke Tanaka ◽  
Koji Okajima ◽  
Masahiko Ikeuchi ◽  
Satoru Tokutomi ◽  
...  
Keyword(s):  
Macromolecular Crowding ◽  
Crowding Effects

Effects of Dispersed Al2O3 Particles on Sintering of LTCC

2008 ◽  
Vol 39-40 ◽  
pp. 375-380
Author(s):  
Ralf Müller ◽  
Stefan Reinsch ◽  
Markus Eberstein ◽  
Joachim Deubener ◽  
A. Thiel ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Al2o3 Particle ◽  
Model Composite ◽  
Heating Microscopy ◽  
Glass Crystal ◽  
Rate Controlled ◽  
Higher Temperature ◽  
Crystal Particle ◽  
Kinetics Of ◽  
Glass Viscosity

The sintering of Low Temperature Co-fired Ceramics prepared from alumoborosilicate glass- and Al2O3 powders of similar small particle size was studied by dilatometry, heating microscopy, microstructure analysis, glass- and effective viscosity measurements. The steric effect of Al3O3 inclusions was studied using a “non-reactive” model composite. With increasing Al3O3 volume fraction ( Φ ≤ 0.45), sintering decelerates and its final stage shifts to higher temperature. The attainable shrinkage is reduced as Al2O3 particle clusters bearing residual pores become more frequent. The kinetics of sintering could be described formally superposing the weighed contributions of differentially sized and randomly composed glass-crystal particle clusters and assuming a sintering rate controlled by the effective matrix viscosity, which increases with Φ and with progressive wetting of Al2O3 particles during densification. The “reactive” model composite shows significant dissolution of Al2O3 into the glass, which has two opposed effects on sintering: reducing Φ and increasing glass viscosity. For the present case ( Φ = 0.25), the latter effect dominates and sintering is retarded by Al2O3 dissolution. Crystallization of wollastonite starts after full densification. Dissolution of Al2O3 was found to promote the subsequent growth of anorthite.

scholarly journals Residue-Level Interrogation of Macromolecular Crowding Effects on Protein Stability

2008 ◽  
Vol 130 (21) ◽  
pp. 6826-6830 ◽  
Author(s):  
Lisa M. Charlton ◽  
Christopher O. Barnes ◽  
Conggang Li ◽  
Jillian Orans ◽  
Gregory B. Young ◽  
...  
Keyword(s):  
Protein Stability ◽  
Macromolecular Crowding ◽  
Residue Level ◽  
Crowding Effects

Macromolecular crowding: effects on actin polymerisation

1997 ◽  
Vol 66 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Robyn A. Lindner ◽  
Gregory B. Ralston
Keyword(s):  
Macromolecular Crowding ◽  
Crowding Effects
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