nr. 477 - 2011 - Institut for Natur, Systemer og Modeller (NSM)
nr. 477 - 2011 - Institut for Natur, Systemer og Modeller (NSM)
nr. 477 - 2011 - Institut for Natur, Systemer og Modeller (NSM)
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vi Contents<br />
Significance of the Apoptotic Wave . . . . . . . . . . . . . . . . . . . . . 33<br />
Michaelis-Menten versus a Hill function . . . . . . . . . . . . . . . . . . 34<br />
Implication of secretion of cytokines upon Ba phagocytosis . . . . . . . 35<br />
Activation by phagocytosis of necrotic β-cells . . . . . . . . . . . . . . . 36<br />
5.8 Discussion of Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . 37<br />
Reversible or irreversible activation? . . . . . . . . . . . . . . . . . . . . 38<br />
The DuCa model with turnover of Ma . . . . . . . . . . . . . . . . . . . 41<br />
6 The Intermediated Model 45<br />
Model observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47<br />
6.1 Fixed Points of the IM Model . . . . . . . . . . . . . . . . . . . . . . . . 48<br />
Stability of the fixed points . . . . . . . . . . . . . . . . . . . . . . . . . 50<br />
Downfall of the IM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53<br />
Phase plane analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54<br />
A brief note on linearizing . . . . . . . . . . . . . . . . . . . . . . . . . . 59<br />
6.2 The IM Including Crowding-Terms . . . . . . . . . . . . . . . . . . . . . 60<br />
6.3 Recapitulation of The Analysis of the IM . . . . . . . . . . . . . . . . . 63<br />
7 A Brief Introduction to Bifurcation Analysis and Numerical Methods 65<br />
7.1 Generic Bifurcations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65<br />
7.2 The Hopf bifurcation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66<br />
7.3 Biol<strong>og</strong>ical Relevance of Bifurcation Analysis . . . . . . . . . . . . . . . . 69<br />
7.4 Choice of Bifurcation Parameters . . . . . . . . . . . . . . . . . . . . . . 69<br />
7.5 Locating the Fixed Points . . . . . . . . . . . . . . . . . . . . . . . . . . 70<br />
Evaluation of stability of the fixed points and detection of bifurcations . 71<br />
8 Bifurcation Diagrams and Analysis 73<br />
8.1 Codimension One Bifurcations . . . . . . . . . . . . . . . . . . . . . . . 73<br />
8.2 Using f1 as the bifurcation parameter . . . . . . . . . . . . . . . . . . . 74<br />
Basic features of the NOD bifurcation diagram . . . . . . . . . . . . . . 74<br />
Eigenvalues, manifolds and behavior of the fixed points on the NODf1-USB 75<br />
Eigenvalues, manifolds and behavior of the fixed points on the NODf1-LUB 79<br />
Combining the analysis of the NODf1-USB and LUB . . . . . . . . . . .<br />
Hidden features in figure 8.1 . . . . . . . . . . . . . . . . . . . . . . . . .<br />
81<br />
84<br />
The Balb/c bifurcation diagram . . . . . . . . . . . . . . . . . . . . . . . 87<br />
8.3 Using f2 as the bifurcation parameter . . . . . . . . . . . . . . . . . . . 88<br />
8.4 Reducing the DuCa-model . . . . . . . . . . . . . . . . . . . . . . . . . . 93<br />
9 Discussion of the Bifurcation Analysis 97<br />
9.1 Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101<br />
10 Conclusion 1 103<br />
11 Expanding and Modifying the DuCa model 105<br />
11.1 Including a Compartment of Healthy β-cells . . . . . . . . . . . . . . . . 105<br />
Model criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105<br />
11.2 First approximation to a governing equation – Model A . . . . . . . . . 106<br />
11.3 Modifying the governing equation – Model B . . . . . . . . . . . . . . . 110