title: Fluid transport in branched structures with temporary closures: a model for quasistatic lung inflation.
abstract: We analyze the problem of fluid transport through a model system relevant to the inflation of a mammalian lung, an asymmetric bifurcating structure containing random blockages that can be removed by the pressure of the fluid itself. We obtain a comprehensive description of the fluid flow in terms of the topology of the structure and the mechanisms which open the blockages. We show that when calculating averaged flow properties of the fluid, the tree structure can be partitioned into a linear superposition of one-dimensional chains. In particular, we relate the pressure-volume P-V relationship of the fluid to the distribution Pi(n) of the generation number n of the tree's terminal branches, a structural property. We invert this relation to obtain a statistical description of the underlying branching structure of the lung, by analyzing experimental pressure-volume data from dog lungs. The Pi(n) extracted from the experimental P-V data agrees well with available data on lung branching structure. Our general results are applicable to any physical system involving transport in bifurcating structures with removable closures.
authors.affiliation: Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215, USA.
authors.forename: Arnab
authors.initials: A
authors.lastname: Majumdar
authors.forename: Adriano M
authors.initials: AM
authors.lastname: Alencar
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Buldyrev
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Hantos
authors.forename: H Eugene
authors.initials: HE
authors.lastname: Stanley
authors.forename: Béla
authors.initials: B
authors.lastname: Suki
mesh_terms: D000818:Animals; D001692:Biological Transport; D004285:Dogs; D008168:Lung / Q000473:pathology*; D008171:Lung Diseases / Q000473:pathology*; D008176:Lung Volume Measurements; D015233:Models, Statistical; D008962:Models, Theoretical; D011312:Pressure; D011659:Pulmonary Gas Exchange; D013997:Time Factors