Absorption and metabolism of fatty acid: inverse problems and uncertainty studies

Fatty acid is the main substance in food diet and constitutes the major energy source. The absorption and metabolism of fatty acids provide the energy supply for biological activities in the human body. Mathematical models may be used to describe the absorption and metabolism processes of fatty acids in different organs in the human body. One of the main challenges in computational biology is to build a suitable macro-scale mathematical model for fatty acids concentrations in the blood stream. In this thesis, several models in the literature are modified by considering the transport in the absorption process and the metabolism in the blood of substances. An absorption delay is included in an interactive system of insulin-glucose-fatty acids model in Chapter 3. Data from existing literature was used in determining parameters, such as transfer rate, related to these models using inverse problem technique. A significant process in the triglyceride absorption is the hydrolysis reaction which releases fatty acids molecules for human activities. Modelling the hydrolysis process is difficult due to the complex reaction in the digestive system. In this study a general form of compartment model is presented and one specific example is provided through the use of a “regulator” built into the compartment model. A multi-objective optimisation problem is resulted from this study and various parameters solved along with a set of in vitro data as demonstrated in Chapter 4. In the absorption process, the substance needs to be transported through absorptive epithelial cells into the blood vessel. The diffusion and reaction at the cellular level have uncertainties unknown to the biologists. In this thesis, the transport of fatty acids in the absorptive epithelial cell is modelled by a reaction-diffusion system at the cellular model in Chapter 5 and the missing information on the membrane of the epithelial cell is treated as uncertainty in the model. The Monte Carlo method is used to study these uncertainties. Numerical experiments demonstrated the use of three models, with suitable parameters, may describe the absorption and metabolism of fatty acids in different organs in the human body.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

University of Greenwich

Year dc:date.issued

2015

Author dc:creator

• Hai, Yang

Advisors dc:contributor.advisor

• Lai, Choi-Hong
• Pericleous, Kyriacos A
• George, Erwin

• QA Mathematics

Language dc:language

en