P(Ω, Ωo, t) for rotational diffusion

1997 ◽  
pp. 404-406
Keyword(s):  
Rotational Diffusion

scholarly journals Rotational Particle Separation in Solutions: Micropolar Fluid Theory Approach

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1072
Author(s):  
Vladimir Shelukhin
Keyword(s):  
Mathematical Model ◽  
Rotational Diffusion ◽  
Particle Separation ◽  
Theory Approach ◽  
Steady Flows ◽  
Concentric Cylinder ◽  
Polar Fluid ◽  
Fluid Theory ◽  
Couette Cell ◽  
Granular Fluid

We develop a new mathematical model for rotational sedimentation of particles for steady flows of a viscoplastic granular fluid in a concentric-cylinder Couette geometry when rotation of the Couette cell inner cylinder is prescribed. We treat the suspension as a micro-polar fluid. The model is validated by comparison with known data of measurement. Within the proposed theory, we prove that sedimentation occurs due to particles’ rotation and rotational diffusion.

scholarly journals How wide is the window opened by high-resolution relaxometry on the internal dynamics of proteins in solution?

2021 ◽  
Vol 75 (2-3) ◽  
pp. 119-131
Author(s):  
Albert A. Smith ◽  
Nicolas Bolik-Coulon ◽  
Matthias Ernst ◽  
Beat H. Meier ◽  
Fabien Ferrage
Keyword(s):  
Nuclear Magnetic Resonance ◽  
High Resolution ◽  
High Field ◽  
Rotational Diffusion ◽  
Relaxation Data ◽  
Internal Dynamics ◽  
Nmr Relaxometry ◽  
Analysis Of Dynamics

AbstractThe dynamics of molecules in solution is usually quantified by the determination of timescale-specific amplitudes of motions. High-resolution nuclear magnetic resonance (NMR) relaxometry experiments—where the sample is transferred to low fields for longitudinal (T1) relaxation, and back to high field for detection with residue-specific resolution—seeks to increase the ability to distinguish the contributions from motion on timescales slower than a few nanoseconds. However, tumbling of a molecule in solution masks some of these motions. Therefore, we investigate to what extent relaxometry improves timescale resolution, using the “detector” analysis of dynamics. Here, we demonstrate improvements in the characterization of internal dynamics of methyl-bearing side chains by carbon-13 relaxometry in the small protein ubiquitin. We show that relaxometry data leads to better information about nanosecond motions as compared to high-field relaxation data only. Our calculations show that gains from relaxometry are greater with increasing correlation time of rotational diffusion.

Rotational diffusion measurements of suspended colloidal particles using two‐dimensional exchange nuclear magnetic resonance

1996 ◽  
Vol 104 (2) ◽  
pp. 509-520 ◽  
Author(s):  
G. A. Barrall ◽  
K. Schmidt‐Rohr ◽  
Y. K. Lee ◽  
K. Landfester ◽  
H. Zimmermann ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Colloidal Particles ◽  
Rotational Diffusion ◽  
Two Dimensional ◽  
Nuclear Magnetic

Correction to “Photophysics and Rotational Diffusion of Hydrophilic Molecule in Polymer and Polyols”

2014 ◽  
Vol 119 (1) ◽  
pp. 379-379
Author(s):  
Aninda Chatterjee ◽  
Banibrata Maity ◽  
Sayeed Ashique Ahmed ◽  
Debabrata Seth
Keyword(s):  
Rotational Diffusion ◽  
Hydrophilic Molecule

scholarly journals Modelling and analysis of bacterial tracks suggest an active reorientation mechanism in Rhodobacter sphaeroides

2014 ◽  
Vol 11 (97) ◽  
pp. 20140320 ◽  
Author(s):  
Gabriel Rosser ◽  
Ruth E. Baker ◽  
Judith P. Armitage ◽  
Alexander G. Fletcher
Keyword(s):  
Rhodobacter Sphaeroides ◽  
Computational Algorithm ◽  
Rotational Diffusion ◽  
Particle Model ◽  
Cell Geometry ◽  
Brownian Rotation ◽  
Swimming Bacteria ◽  
Run And Tumble ◽  
Open Question ◽  
Straight Lines

Most free-swimming bacteria move in approximately straight lines, interspersed with random reorientation phases. A key open question concerns varying mechanisms by which reorientation occurs. We combine mathematical modelling with analysis of a large tracking dataset to study the poorly understood reorientation mechanism in the monoflagellate species Rhodobacter sphaeroides . The flagellum on this species rotates counterclockwise to propel the bacterium, periodically ceasing rotation to enable reorientation. When rotation restarts the cell body usually points in a new direction. It has been assumed that the new direction is simply the result of Brownian rotation. We consider three variants of a self-propelled particle model of bacterial motility. The first considers rotational diffusion only, corresponding to a non-chemotactic mutant strain. Two further models incorporate stochastic reorientations, describing ‘run-and-tumble’ motility. We derive expressions for key summary statistics and simulate each model using a stochastic computational algorithm. We also discuss the effect of cell geometry on rotational diffusion. Working with a previously published tracking dataset, we compare predictions of the models with data on individual stopping events in R. sphaeroides . This provides strong evidence that this species undergoes some form of active reorientation rather than simple reorientation by Brownian rotation.

Rotational Diffusion Analysis of Polyethylene Glycol Induced Protein Interactions

2011 ◽  
Vol 115 (41) ◽  
pp. 11786-11792 ◽  
Author(s):  
Daisuke Takahashi ◽  
Shoji Yamashita ◽  
Om Prakash ◽  
Etsuko Nishimoto
Keyword(s):  
Polyethylene Glycol ◽  
Protein Interactions ◽  
Rotational Diffusion ◽  
Diffusion Analysis
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