Particle capture into the lung made simple?
Particle capture into the lung made simple?
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DOI：
10.1152/japplphysiol.00866.2010
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发表时间：
2011-06-01
影响因子：
3.3
通讯作者：
Filoche, Marcel
中科院分区：
文献类型：
--
作者：
de Vasconcelos, Talita Felipe;Sapoval, Bernard;Filoche, Marcel
了解进入人体呼吸系统的颗粒物的影响分布至关重要，因为它不仅关系到大气污染物或各种粉尘，而且关系到气雾剂治疗和药物输送的效率。为了模拟这一过程，目前的方法包括对空气动力学和颗粒捕获现象进行越来越复杂的计算，这些计算以几何形式执行，试图以越来越真实的方式模拟肺部，以产生尽可能多的气道。它们的捕获是空气动力学流线的细节和所产生的流动中的颗粒阻力力学之间复杂的相互作用的结果。相比之下，目前的工作提出了一个主要的简化，适用于大多数呼吸道世代在安静的呼吸。在这个背景下，关注粒子逃逸而不是捕获揭示了整个过程中的一个更简单的结构。当引力可以忽略时，我们通过计算各种模型几何中的逃逸率表明，尽管逃逸过程仍然很复杂，但逃逸过程可以描述为一个乘性逃逸级联，其中每个基本步骤都与一个单独的分叉相关联。总而言之，理解粒子捕获可能不需要计算整个肺结构中的粒子沉积，但在某些区域可以使用我们在单个现实分支中连续计算的更简单方法来简化。将重力重新引入到我们的模型中，我们证明了这个乘法模型仍然可以成功地应用到多达九代，这取决于粒子类型和呼吸条件。
Understanding the impact distribution of particles entering the human respiratory system is of primary importance as it concerns not only atmospheric pollutants or dusts of various kinds but also the efficiency of aerosol therapy and drug delivery. To model this process, current approaches consist of increasingly complex computations of the aerodynamics and particle capture phenomena, performed in geometries trying to mimic lungs in a more and more realistic manner for as many airway generations as possible. Their capture results from the complex interplay between the details of the aerodynamic streamlines and the particle drag mechanics in the resulting flow. In contrast, the present work proposes a major simplification valid for most airway generations at quiet breathing. Within this context, focusing on particle escape rather than capture reveals a simpler structure in the entire process. When gravity can be neglected, we show by computing the escape rates in various model geometries that, although still complicated, the escape process can be depicted as a multiplicative escape cascade in which each elementary step is associated with a single bifurcation. As a net result, understanding of the particle capture may not require computing particle deposition in the entire lung structure but can be abbreviated in some regions using our simpler approach of successive computations in single realistic bifurcations. Introducing gravity back into our model, we show that this multiplicative model can still be successfully applied on up to nine generations, depending on particle type and breathing conditions.