scholarly journals Enhanced Diffusion by Reversible Binding to Active Polymers

2021 ◽  
Vol 54 (4) ◽  
pp. 1850-1858 ◽  
Author(s):  
Shankar Lalitha Sridhar ◽  
Jeffrey Dunagin ◽  
Kanghyeon Koo ◽  
Loren Hough ◽  
Franck Vernerey
Keyword(s):  
Reversible Binding ◽  
Enhanced Diffusion

scholarly journals Enhanced diffusion by reversible binding to active polymers

2021 ◽  
Author(s):  
Shankar Lalitha Sridhar ◽  
Jeffrey Dunagin ◽  
Kanghyeon Koo ◽  
Loren Hough ◽  
Franck J Vernerey
Keyword(s):  
Relative Length ◽  
Synthetic Polymers ◽  
Diffusive Transport ◽  
Optimum Conditions ◽  
Reversible Binding ◽  
Macromolecular Transport ◽  
Enhanced Diffusion ◽  
Mechanics Model ◽  
Random Forces ◽  
Insight Into

Cells are known to use reversible binding to active biopolymer networks to allow diffusive transport of particles in an otherwise impenetrable mesh. We here determine the motion of a particle that experiences random forces during binding and unbinding events while being constrained by attached polymers. Using Monte-Carlo simulations and a statistical mechanics model, we find that enhanced diffusion is possible with active polymers. However, this is possible only under optimum conditions that has to do with the relative length of the chains to that of the plate. For example, in systems where the plate is shorter than the chains, diffusion is maximum when many chains have the potential to bind but few remain bound at any one time. Interestingly, if the chains are shorter than the plate, we find that diffusion is maximized when more active chains remain transiently bound. The model provides insight into these findings by elucidating the mechanisms for binding-mediated diffusion in biology and design rules for macromolecular transport in transient synthetic polymers.

Ion Beam Mixing of Ni-Ti Bilayered Thin Films

1985 ◽  
Vol 43 ◽  
pp. 290-291
Author(s):  
A. K. Rai ◽  
R. S. Bhattacharya ◽  
M. H. Rashid
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Amorphous Alloys ◽  
Ion Beam ◽  
Ion Bombardment ◽  
High Energy ◽  
Mixing Efficiency ◽  
Ion Beam Mixing ◽  
Enhanced Diffusion ◽  
Binary Metal

Ion beam mixing has recently been found to be an effective method of producing amorphous alloys in the binary metal systems where the two original constituent metals are of different crystal structure. The mechanism of ion beam mixing are not well understood yet. Several mechanisms have been proposed to account for the observed mixing phenomena. The first mechanism is enhanced diffusion due to defects created by the incoming ions. Second is the cascade mixing mechanism for which the kinematicel collisional models exist in the literature. Third mechanism is thermal spikes. In the present work we have studied the mixing efficiency and ion beam induced amorphisation of Ni-Ti system under high energy ion bombardment and the results are compared with collisional models. We have employed plan and x-sectional veiw TEM and RBS techniques in the present work.

Effects of Concurrent Co or Ti Silicidation on Transient Diffusion and End-of-Range Damage in Phosphorus Implanted Silicon

1992 ◽  
Vol 262 ◽  
Author(s):  
J.W. Honeycutt ◽  
J. Ravi ◽  
G. A. Rozgonyi
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Complete Removal ◽  
Dislocation Loops ◽  
Enhanced Diffusion ◽  
Depth Profiles ◽  
Enhanced Dissolution ◽  
Implantation Damage ◽  
Transmission Electron ◽  
Defect Behavior ◽  
Secondary Ion

ABSTRACTThe effects of Ti and Co silicidation on P+ ion implantation damage in Si have been investigated. After silicidation of unannealed 40 keV, 2×1015 cm-2 P+ implanted junctions by rapid thermal annealing at 900°C for 10–300 seconds, secondary ion mass spectrometry depth profiles of phosphorus in suicided and non-silicided junctions were compared. While non-silicided and TiSi2 suicided junctions exhibited equal amounts of transient enhanced diffusion behavior, the junction depths under COSi2 were significantly shallower. End-of-range interstitial dislocation loops in the same suicided and non-silicided junctions were studied by planview transmission electron microscopy. The loops were found to be stable after 900°C, 5 minute annealing in non-silicided material, and their formation was only slightly effected by TiSi2 or COSi2 silicidation. However, enhanced dissolution of the loops was observed under both TiSi2 and COSi2, with essentially complete removal of the defects under COSi2 after 5 minutes at 900°C. The observed diffusion and defect behavior strongly suggest that implantation damage induced excess interstitial concentrations are significantly reduced by the formation and presence of COSi2, and to a lesser extent by TiSi2. The observed time-dependent defect removal under the suicide films suggests that vacancy injection and/or interstitial absorption by the suicide film continues long after the suicide chemical reaction is complete.

ChemInform Abstract: REVERSIBLE BINDING OF ACETYLENE BY OXOBIS(DIETHYLDITHIOCARBAMATE)MOLYBDENUM

1978 ◽  
Vol 9 (24) ◽  
Author(s):  
E. A. MAATTA ◽  
R. A. D. WENTWORTH ◽  
W. E. NEWTON ◽  
J. W MCDONALD ◽  
G. D. WATT
Keyword(s):  
Reversible Binding

scholarly journals Direction-dependent turning leads to anisotropic diffusion and persistence

2021 ◽  
pp. 1-37
Author(s):  
N. LOY ◽  
T. HILLEN ◽  
K. J. PAINTER
Keyword(s):  
Anisotropic Diffusion ◽  
Cell Movement ◽  
Orientation Dependence ◽  
Transport Equations ◽  
Heterogeneous Environment ◽  
Enhanced Diffusion ◽  
Mesoscopic Level

Cells and organisms follow aligned structures in their environment, a process that can generate persistent migration paths. Kinetic transport equations are a popular modelling tool for describing biological movements at the mesoscopic level, yet their formulations usually assume a constant turning rate. Here we relax this simplification, extending to include a turning rate that varies according to the anisotropy of a heterogeneous environment. We extend known methods of parabolic and hyperbolic scaling and apply the results to cell movement on micropatterned domains. We show that inclusion of orientation dependence in the turning rate can lead to persistence of motion in an otherwise fully symmetric environment and generate enhanced diffusion in structured domains.

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