title: Characterisation of mixing in the proximal duodenum of the rat during longitudinal contractions and comparison with a fluid mechanical model based on spatiotemporal motility data.
abstract: The understanding of mixing and mass transfers of nutrients and drugs in the small intestine is of prime importance in creating formulations that manipulate absorption and digestibility. We characterised mixing using a dye tracer methodology during spontaneous longitudinal contractions, i.e. pendular activity, in 10 cm segments of living proximal duodenum of the rat maintained ex-vivo. The residence time distribution (RTD) of the tracer was equivalent to that generated by a small number (8) of continuous stirred tank reactors in series. Fluid mechanical modelling, that was based on real sequences of longitudinal contractions, predicted that dispersion should occur mainly in the periphery of the lumen. Comparison with the experimental RTD showed that centriluminal dispersion was accurately simulated whilst peripheral dispersion was underestimated. The results therefore highlighted the potential importance of micro-phenomena such as microfolding of the intestinal mucosa in peripheral mixing. We conclude that macro-scale modeling of intestinal flow is useful in simulating centriluminal mixing, whereas multi-scales strategies must be developed to accurately model mixing and mass transfers at the periphery of the lumen.
authors.affiliation: INRA, AgroParisTech, UMR 782 Génie et Microbiologie des Procédés Alimentaires, 78850, Thiverval-Grignon, France.
authors.forename: Clément
authors.initials: C
authors.lastname: de Loubens
authors.affiliation: Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand.
authors.forename: Roger G
authors.initials: RG
authors.lastname: Lentle
authors.affiliation: Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand.
authors.forename: Corrin
authors.initials: C
authors.lastname: Hulls
authors.affiliation: Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand.
authors.forename: Patrick W M
authors.initials: PW
authors.lastname: Janssen
authors.affiliation: Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Love
authors.affiliation: Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
authors.forename: J Paul
authors.initials: JP
authors.lastname: Chambers
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D004386:Duodenum / Q000502:physiology*; D005769:Gastrointestinal Motility; D057446:Hydrodynamics; D055595:Mechanical Phenomena; D008954:Models, Biological; D009119:Muscle Contraction; D051381:Rats; D017207:Rats, Sprague-Dawley; D062211:Spatio-Temporal Analysis
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