Related Experiment Video
Updated: Jun 27, 2026
13:22
Adhesion Frequency Assay for In Situ Kinetics Analysis of Cross-Junctional Molecular Interactions at the Cell-Cell Interface
Published on: November 2, 2011
Exact steady-state velocity of ratchets driven by random sequential adsorption.
Maria R D'Orsogna1, Tom Chou, Tibor Antal
1Department of Mathematics, UCLA, Los Angeles, CA 90095-1555.
Journal of Physics A: Mathematical and General
|December 17, 2008
Summary
We found that smaller adsorbing particles speed up polymer translocation through a pore. Smaller particles also reduce fluctuations in this ratcheting process, improving efficiency.
Area of Science:
- Polymer physics
- Statistical mechanics
- Soft matter physics
Background:
- Polymer translocation through nanopores is crucial for biological processes and nanotechnology.
- Understanding the dynamics of translocation driven by particle adsorption is complex due to coupled kinetics.
Purpose of the Study:
- To investigate the discrete translocation of polymers through a pore driven by particle adsorption.
- To determine the effect of particle size on translocation velocity and efficiency.
- To analyze the underlying statistical mechanics of the ratcheting process.
Main Methods:
- Analytical solution for the steady-state distribution of the gap between the pore wall and deposited particles.
- Monte Carlo simulations to validate theoretical findings and explore particle size effects.
- Comparison of ratcheting efficiencies for different particle sizes.
Main Results:
- Derived the exact steady-state distribution for the gap, enabling calculation of mean translocation velocity.
- Demonstrated that smaller adsorbing particles lead to faster translocation.
- Observed reduced dispersion in translocation dynamics with smaller particles via simulations.
- Defined and compared the relative efficiencies of particle-driven ratcheting.
Conclusions:
- Particle size is a critical parameter influencing the speed and smoothness of polymer translocation.
- The described model provides a framework for understanding and optimizing particle-driven translocation systems.
- The study introduces a zone-refinement concept applicable to particle-mediated transport processes.
Related Concept Videos
01:26Reaction Mechanisms: The Steady-State Approximation
The steady-state approximation, also referred to as the quasi-steady-state approximation to differentiate it from a true steady state, is a widely used method for simplifying calculations in complex reaction mechanisms. This approach is particularly useful when dealing with multi-step reactions that involve reverse reactions or several steps, which can significantly increase mathematical complexity and make the reactions nearly unsolvable analytically.The steady-state approximation operates on...
01:29Reaction Mechanisms: Rate-limiting Step Approximation
The rate-determining step, or RDS, in a chemical reaction is the slowest step that determines the overall reaction rate. It is identified by using the observed rate law and typically involves approximation methods like the RDS approximation or the steady-state approximation.In the RDS approximation, also known as the rate-limiting-step or equilibrium approximation, the reaction mechanism consists of one or more reversible reactions near equilibrium, followed by a slower RDS, and then one or...
01:05Static Equilibrium - I
A rigid body is said to be in dynamic equilibrium when both its linear and angular acceleration are zero, relative to an inertial frame of reference. This means that a body in equilibrium can be moving, but only when its linear and angular velocities are constant. A rigid body is said to be in static equilibrium when it is at rest in the selected frame of reference. The distinction between static equilibrium (e.g., a state of rest) and dynamic equilibrium (e.g, a state of uniform motion) is...
01:10Relative Motion Analysis - Acceleration
A slider-crank mechanism converts rotational motion from the crank into linear motion of the slider or vice versa. This mechanism consists of three main parts: the crank, the connecting rod, and the slider. The movement of the slider-crank is an example of general plane motion as the fluctuating angle between the crank and the connecting rod. Consider a segment AB where point A is at the end of the slider and point B is on the diametrically opposite end to point A, on a crack. The variance in...
01:18Static Friction
Static friction is a force that opposes the relative motion or tendency of motion between two surfaces in contact. It plays a crucial role in our daily lives, from walking on the ground to driving a car.
For example, consider a scenario where a truck is connected to a car by a rope, ready to tow it along a road. When no external force is applied by the truck, the car remains stationary and is said to be in static equilibrium. In this case, the forces acting on the car, such as gravity and the...
For example, consider a scenario where a truck is connected to a car by a rope, ready to tow it along a road. When no external force is applied by the truck, the car remains stationary and is said to be in static equilibrium. In this case, the forces acting on the car, such as gravity and the...
01:21Rolling Resistance
When a solid cylinder rolls steadily on a rigid surface, the normal force applied by the surface on the cylinder is perpendicular to the tangent at the contact point. However, since no materials are entirely rigid, the surface's reaction to the cylinder involves a range of normal pressures.
For instance, imagine a hard cylinder rolling on a comparatively soft surface. The cylinder's weight compresses the surface beneath it. As the cylinder moves, the material in front of it slows down due to...
For instance, imagine a hard cylinder rolling on a comparatively soft surface. The cylinder's weight compresses the surface beneath it. As the cylinder moves, the material in front of it slows down due to...