Video Experimental Relacionado
Updated: Dec 26, 2025
08:01
The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
8.9K
Los vuelos de Loopy Lévy mejoran la difusión del marcador en las suspensiones activas
Kiyoshi Kanazawa1,2, Tomohiko G Sano3,4, Andrea Cairoli5,6,7
1Faculty of Engineering, Information and Systems, University of Tsukuba, Tsukuba, Japan. kiyoshi@sk.tsukuba.ac.jp.
Nature
|March 20, 2020
Resumen
Los sistemas activos exhiben una difusión mejorada y estadísticas no gaussianas, que se desvían del movimiento browniano. Una nueva teoría explica este movimiento trazador, prediciendo un régimen de vuelo sintonizable de Lévy crucial para comprender la dinámica de la materia activa.
Área de la Ciencia:
- La física
- Química
- Biología
- Física de la materia activa
- Mecánica estadística
Sus antecedentes:
- El movimiento browniano modela la difusión en sistemas de equilibrio.
- Los sistemas del mundo real a menudo están fuera de equilibrio debido a procesos activos.
- La difusión del trazador en medios activos muestra una difusión mejorada y estadísticas no gaussianas, a diferencia del movimiento browniano.
Objetivo del estudio:
- Desarrollar una teoría integral para la difusión de marcadores en medios activos.
- Explique el surgimiento de la difusión mejorada y las estadísticas no gaussianas de la dinámica microscópica.
- Modela las interacciones hidrodinámicas entre los marcadores y los nadadores activos.
Principales métodos:
- Desarrolló un marco teórico para modelar las interacciones hidrodinámicas.
- Utilizó un proceso de Poisson de color no Markoviano para describir el movimiento del trazador.
- Los desplazamientos del marcador y los coeficientes de difusión analizados.
Principales resultados:
- El trazador sigue un proceso de Poisson de color no markovia, explicando las observaciones empíricas.
- Predijo un régimen de vuelo de Lévy de larga duración con exponentes de ley de potencia ajustables.
- Se ha demostrado que la densidad de los nadadores influye en la duración del régimen de vuelo de Lévy.
Conclusiones:
- La teoría desarrollada proporciona una explicación completa de la difusión del trazador en medios activos.
- Los hallazgos tienen implicaciones para la comprensión de la termodinámica del sistema activo y los procesos biológicos como la búsqueda de alimento.
- El marco puede guiar el diseño de máquinas artificiales a nanoescala y analizar las interacciones de partículas.
Videos de Conceptos Relacionados
01:17Colloids and Suspensions
2.9K
Children at play often make suspensions such as mixtures of mud and water, flour and water, or a suspension of solid pigments in water known as tempera paint. These suspensions are heterogeneous mixtures composed of relatively large particles visible to the naked eye or seen with a magnifying glass. They are cloudy, and the suspended particles settle out after mixing. The suspended particles in a suspension settle out after some time of mixing. The separation of particles from a suspension is...
2.9K
01:17Passive Diffusion: Overview and Kinetics
1.2K
Passive diffusion is a critical process that allows small lipophilic drugs to cross the cell membrane along a concentration gradient. This mechanism's efficiency depends on four primary factors: the membrane's surface area, the drug's lipid-water partition coefficient, the concentration gradient, and the membrane's thickness.
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting...
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting...
1.2K
01:27Laminar Flow
2.0K
Laminar flow represents a smooth, orderly fluid motion where particles move along parallel paths, resulting in minimal mixing between layers. Streamlined particle paths characterize this flow regime and occur under conditions where viscous forces dominate over inertial forces. The distinction between laminar, transitional, and turbulent flow is primarily determined by the Reynolds number, a dimensionless quantity calculated as:
2.0K
01:17Accelerating Fluids
2.0K
When a fluid is in constant acceleration, the pressure and buoyant force equations are modified. Suppose a beaker is placed in an elevator accelerating upward with a constant acceleration, a. In the beaker, assume there is a thin cylinder of height h with an infinitesimal cross-sectional area, ΔS.
The motion of the liquid within this infinitesimal cylinder is considered to obtain the pressure difference. Three vertical forces act on this liquid:
The motion of the liquid within this infinitesimal cylinder is considered to obtain the pressure difference. Three vertical forces act on this liquid:
2.0K
01:24Reynolds Transport Theorem
1.7K
The Reynolds transport theorem provides a framework to relate the time rate of change of an extensive property within a system to that in a control volume, which is crucial for analyzing fluid dynamics. Extensive properties, such as mass, velocity, acceleration, temperature, and momentum, can be expressed in terms of the mass of a fluid portion. These properties are called extensive because they depend on the system's size, while intensive properties are their corresponding values per unit...
1.7K
01:15Theories of Dissolution: Diffusion Layer Model
1.5K
Dissolution, the process by which drug particles dissolve in a solvent, is explained by the diffusion layer model, a theoretical framework that simulates the absorption of oral drugs and allows us to analyze experimental data.
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
This process starts with a thin layer, saturated with the drug, forming at the interface between the solid and liquid. The solute then diffuses from this layer into the main solution. The Noyes-Whitney equation suggests that the rate of dissolution relies on the diffusion...
1.5K