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Explore nonlinear equations in biomedical engineering, from the Colebrook Equation to receptor-ligand dynamics. Learn methods like Newton-Raphson and examples of receptor occupancy calculations.
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ECE602 BME I Nonlinear Equations in Biomedical Engineering
Examples of nonlinear equations in BME • The Method of Successive Substitution • The Method of False Position (Linear Interpolation) • The Newton-Raphson Method • Newton’s method for Simultaneous Nonlinear Equations • Implementation issues
Nonlinear Equations in BME • Colebrook Equation • Laminar flow of blood when catheter is used • b: the friction factor, dimensionless, used to determine the change in the velocity • Re: Reynolds number, used to characterize flows (Re>2000, turbulent)
Nonlinear Equations in BME • Receptor occupancy during receptor-ligand dynamics • Cell membrane receptors: bind to specific ligands (hormones, growth factors), and trigger intracellular signaling in mammalian cells. • Multimetric receptors: possess multiple binding units –making the binding chemistry nonlinear
K: equilibrium constant C: concentration Nonlinear Equations in BME Receptor occupancy during receptor-ligand dynamics Example: A: trimetrc receptor B: dimetric receptor L: the ligand D: receptor—bound ligand
Nonlinear Equations in BME Receptor occupancy during receptor-ligand dynamics Example: x1: fractional occupancy of A; x2: fractional occupancy of B CA,0, CB,0, CL,0: the initial concentrations
Convergence condition: for all x in the search interval Successive Substitution • x0: initial guess • Iterative formula: • Terminating condition:
Successive Substitution • Advantages • It can be started with only a single point • No need for calculating the derivative of the function
False Position (Linear Interpolation) • Initial guess: x0, x1 ( ) • Iteration: • Determine x+, x- • Terminating condition: x+: the point at which x-: the point at which
False Position (Linear Interpolation) • Advantage • Doe not require evaluating derivatives. • Disadvantage • The accuracy and speed of convergence depend on the choice of initial guesses.