title: Using discrete multi-physics for detailed exploration of hydrodynamics in an in vitro colon system.
abstract: We developed a mathematical model that describes the motion of viscous fluids in the partially-filled colon caused by the periodic contractions of flexible walls (peristalsis). In-vitro data are used to validate the model. The model is then used to identify two fundamental mechanisms of mass transport: the surfing mode and the pouring mode. The first mechanism is faster, but only involves the surface of the liquid. The second mechanism causes deeper mixing, and appears to be the main transport mechanism. Based on the gained understanding, we propose a series of measures that can improve the reliability of in-vitro models. The tracer in PET-like experiments, in particular, should not be injected in the first pocket, and its viscosity should be as close as possible to that of the fluid. If these conditions are not met, the dynamics of the tracer and the fluid diverge, compromising the accuracy of the in-vitro data.
authors.affiliation: School of Chemical Engineering, University of Birmingham, Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom. Electronic address: a.alexiadis@bham.ac.uk.
authors.forename: A
authors.initials: A
authors.lastname: Alexiadis
authors.affiliation: School of Chemical Engineering, University of Birmingham, Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: K
authors.initials: K
authors.lastname: Stamatopoulos
authors.affiliation: School of Chemical Engineering, University of Birmingham, Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: W
authors.initials: W
authors.lastname: Wen
authors.affiliation: College of Medical and Dental Sciences, University of Birmingham, Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: H K
authors.initials: HK
authors.lastname: Batchelor
authors.affiliation: School of Chemical Engineering, University of Birmingham, Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: S
authors.initials: S
authors.lastname: Bakalis
authors.affiliation: School of Chemical Engineering, University of Birmingham, Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Barigou
authors.affiliation: School of Chemical Engineering, University of Birmingham, Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: M J H
authors.initials: MJ
authors.lastname: Simmons
mesh_terms: D000465:Algorithms; D003106:Colon / Q000502:physiology*; D003198:Computer Simulation; D005772:Gastrointestinal Transit / Q000502:physiology*; D006801:Humans; D057446:Hydrodynamics; D008954:Models, Biological; D010528:Peristalsis / Q000502:physiology*; D015203:Reproducibility of Results; D012212:Rheology / Q000379:methods*; D012680:Sensitivity and Specificity; D014783:Viscosity
keywords: Fluid dynamics; Fluid-structure interaction; Intestine; Mathematical modelling; Peristalsis; Smoothed particle hydrodynamics