Boulder Fluid and Thermal Sciences Seminar Series

Tuesday, February 6, 2018

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3:30pm-4:30pm (refreshments at 3:15pm)
Bechtel Collaboratory
Discovery Learning Center
University of Colorado at Boulder

Add to Calendar 02/06/2018 3:30:00 PM 02/06/2018 4:30:00 PM 9 Boulder Fluid and Thermal Sciences Seminar Discovery Learning Center, University of Colorado, Boulder MM/DD/YYYY

Discovery of a "Magenstrasse" and other Gastric Curiosities with a Lattice Boltzmann Model of the Human Stomach

James Brasseur University of Colorado, Boulder

Mechanically, the stomach is a controlled pump that empties viscous heterogeneous liquid content from a bag (the fundus) through a sphincteric valve (the pylorus) by slow squeeze of fundic muscle. In addition, however, periodic peristaltic contraction waves travel towards the pylorus in the lower stomach (antrum), elevating pressure locally, presumably to periodically enhance emptying. My medical collaborators measured antral contractions with concurrent manometry and MRI in vivo; we analyzed the data to show that, as each antral contraction wave approaches the pylorus the pylorus momentarily closes, right when an open pylorus would have allowed a surge of fluid flow into the intestines! This is a curiosity. To study in more detail the consequences of the curious phasic relationship between the passage of antral contraction waves and pyloric opening, we applied a lattice Boltzmann computational fluid dynamics model with moving boundary conditions and a stomach geometry model parameterized using time-resolved MRI. Analysis lead to the discovery of a second curiosity: the antral contraction waves produce a narrow path of emptying, or "Magenstrasse" (German for "stomach road") that directs content from the top of the stomach to the pylorus in relatively short time with little mixing. This discovery might explain a well-known observation in pharmaceutics, that the response time of a drug after ingestion is extremely variable. (If a drug capsule opened in the stomach off the Magenstrasse, it would take over an hour for drug particles to empty into the intestine and drug to enter the circulatory system, while if release occurred on the Magenstrasse, activation time would be quick!) The fluid dynamics underlying this seemingly simple organ turns out to be surprisingly interesting.


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Support from Herbert and Karen Vogel is gratefully acknowledged through a Vogel Faculty Fellowship at the University of Colorado, Boulder.



The seminar is held at the Discovery Learning Center (DLC) at the University of Colorado. Parking is free with a permit, which is provided at the seminar. The location for parking is shown in the map below.

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