扩散的不同行为扩散性动力学基于三种不同的分数布朗运动的定义
Wei Wang1, Qing Wei2, Aleksei V Chechkin1,3,4,5
1University of Potsdam, Institute of Physics & Astronomy, 14476 Potsdam, Germany.
Physical review. E
|August 19, 2025
概括
在分数布朗运动 (FBM) 模型中探索扩散扩散性 (DD) 揭示了不同的行为. 随机扩散率的相关性导致意想不到的交叉,影响生物和软物质系统的统计性质.
科学领域:
- 统计力学 统计力学
- 软物质物理学 软物质物理学
- 生物物理学的生物物理.
背景情况:
- 扩散扩散率 (DD) 模型是扩散系数的随机波动.
- 分布朗运动 (FBM) 用于模拟异常扩散.
- 在FBM框架中理解DD对于复杂的系统至关重要.
研究的目的:
- 研究DD对三种不同的FBM模型的影响.
- 为了分析统计属性,如MSD,MSI,ACVF和PDF.
- 为了比较朗格温方程 (LE-FBM-DD),韦尔 (MN-FBM-DD) 和里曼-利乌维尔 (RL-FBM-DD) 积分表示的行为.
主要方法:
- 制定了三种FBM通用的DD模型:LE-FBM-DD,MN-FBM-DD和RL-FBM-DD.
- 检查统计属性:平均平方位移 (MSD),平均平方增量 (MSI),自转变函数 (ACVF) 和概率密度函数 (PDF).
- 分析随机扩散性对模型行为的相关性的影响.
主要成果:
- 与之前的假设相反,MN-FBM-DD和LE-FBM-DD模型显示出不同的MSD和MSI.
- 由于扩散性相关性,LE-FBM-DD显示了交叉行为.
- MSI和ACVF在RL-FBM-DD中是非静止的,但在MN-FBM-DD和LE-FBM-DD中是静止的.
- 所有模型都显示了随着时间的推移,从非高斯文档到高斯文档的PDF文件的过渡.
结论:
- 选择FBM框架显著影响DD模型的行为.
- 扩散度的相关性引入了复杂的动态,这些动态无法被更简单的模型所捕捉.
- 这些发现指导了对异质生物和软物质系统的适当FBM通用模型的选择.
相关概念视频
Behavior of Gas Molecules: Molecular Diffusion, Mean Free Path, and Effusion
29.4K
Although gaseous molecules travel at tremendous speeds (hundreds of meters per second), they collide with other gaseous molecules and travel in many different directions before reaching the desired target. At room temperature, a gaseous molecule will experience billions of collisions per second. The mean free path is the average distance a molecule travels between collisions. The mean free path increases with decreasing pressure; in general, the mean free path for a gaseous molecule will be...
29.4K
Diffusion
198.9K
Diffusion is the passive movement of substances down their concentration gradients—requiring no expenditure of cellular energy. Substances, such as molecules or ions, diffuse from an area of high concentration to an area of low concentration in the cytosol or across membranes. Eventually, the concentration will even out, with the substance moving randomly but causing no net change in concentration. Such a state is called dynamic equilibrium, which is essential for maintaining overall...
198.9K
Diffusion on Chromatography Columns
760
In column chromatography, when an analyte is introduced as a narrow band at the top of the column, the solutes begin to separate and broaden, developing a Gaussian profile. This broadening occurs due to various factors, such as longitudinal diffusion.
Longitudinal diffusion occurs when the solute molecules in the mobile phase diffuse from the more concentrated center of the chromatographic band to the more dilute regions on either side, both towards and against the flow direction. This...
Longitudinal diffusion occurs when the solute molecules in the mobile phase diffuse from the more concentrated center of the chromatographic band to the more dilute regions on either side, both towards and against the flow direction. This...
760
Protein Diffusion in the Membrane
4.6K
Proteins show rotational as well as lateral diffusion across the membrane. The lateral diffusion of proteins was confirmed through the cell fusion experiment where mouse and human cells were fused, resulting in hybrid cells. When the human and mouse cells fused, the specific membrane proteins on human and mouse cells were marked with the red and green-fluorescent markers, respectively. Initially, the red and green fluorescence was located on the respective hemisphere of the cell. As time...
4.6K
Theories of Dissolution: The Danckwerts' Model and Interfacial Barrier Model
433
Various dissolution theories provide insight into the factors that influence the dissolution rate. Danckwerts' Model suggests that turbulence, rather than a stagnant layer, characterizes the dissolution medium at the solid-liquid interface. In this model, the agitated solvent contains macroscopic packets that move to the interface via eddy currents, facilitating the absorption and delivery of the drug to the bulk solution. The regular replenishment of solvent packets maintains the...
433
Passive Diffusion: Overview and Kinetics
717
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...
717


