论文标题
在Adam-Delbrück降低维度方案与直接扩散搜索的搜索效率
Search efficiency in the Adam-Delbrück reduction-of-dimensionality scenario versus direct diffusive search
论文作者
论文摘要
时间瞬间 - 第一次通用时间（FPT） - 当第一次到达位于有界三维结构域表面上的不动靶时，氧气或信号蛋白等扩散粒子（例如，氧气或信号蛋白）时的时间瞬间（FPT）（fpt）（例如，血液分子或细胞核）是多样性的discemistial discemitive discemitive discemitive discemitive discemitive discemitive discemitive scale scale scale scale scale scale scale scale scale scale scale scale scale tise timeristial。以及在各种细胞间和细胞内信号转导途径的中间阶段。 Adam和Delbrück提出了降低维度概念，根据该概念，配体首先与该靶标的任何位置的任何点结合，然后沿该表面扩散直到定位目标。在这项工作中，我们分析了这种情况的效率，并与直接搜索过程的效率相遇，在该过程中，该过程直接从散装中接近目标，而无法通过表面扩散来帮助。我们考虑两种情况：（i）从固定或随机位置启动单个配体并搜索目标，以及（ii）当$ n $配体从同一点或随机位置开始时，“放大”信号的情况是，搜索终止于最快到达目标。对于此类设置，我们超越了常规分析，该分析仅比较相应的FPT的平均值。取而代之的是，我们计算FPT在方案中的完整概率密度函数，并研究其整体特征 - 目标$ t $的“生存”概率。在此基础上，我们研究了两种情况的效率如何受到各种参数的控制，并且单一的现实条件在这些条件下，降低差异性方案的表现优于直接搜索。
The time instant -- the first-passage time (FPT) -- when a diffusive particle (e.g., a ligand such as oxygen or a signalling protein) for the first time reaches an immobile target located on the surface of a bounded three-dimensional domain (e.g., a hemoglobin molecule or the cellular nucleus) is a decisive characteristic time-scale in diverse biophysical and biochemical processes, as well as in intermediate stages of various inter- and intra-cellular signal transduction pathways. Adam and Delbrück put forth the reduction-of-dimensionality concept, according to which a ligand first binds non-specifically to any point of the surface on which the target is placed and then diffuses along this surface until it locates the target. In this work, we analyse the efficiency of such a scenario and confront it with the efficiency of a direct search process, in which the target is approached directly from the bulk and not aided by surface diffusion. We consider two situations: (i) a single ligand is launched from a fixed or a random position and searches for the target, and (ii) the case of "amplified" signals when $N$ ligands start either from the same point or from random positions, and the search terminates when the fastest of them arrives to the target. For such settings, we go beyond the conventional analyses, which compare only the mean values of the corresponding FPTs. Instead, we calculate the full probability density function of FPTs for both scenarios and study its integral characteristic -- the "survival" probability of a target up to time $t$. On this basis, we examine how the efficiencies of both scenarios are controlled by a variety of parameters and single out realistic conditions in which the reduction-of-dimensionality scenario outperforms the direct search.
