Dr. Timsina’s Talk: Identifiability and optimal control analysis of HIV infection and opioid addiction model.

Abstract: In a compartmental model of HIV infection and opioid addiction, dynamics such as equilibria, basic reproduction number, and invasion numbers are presented. Identifiability and estimation of the parameters of the model are highlighted. Moreover, the effect of four distinct controls such as treatment for addictions, health care education about not sharing syringes, highly active antiretroviral therapy (HAART), and rehab treatment for opiate addicts who are HIV infected are discussed presenting some simulation outcomes.

Evan’s Talk: How do tension ratios determine morphometry in physical models of notochord cell packing?

Abstract: The physical and geometric aspects of notochords are investigated using a model of finite-length notochords, with interior vacuolated cells arranged in two common packing configurations, and sheath modeled as homogeneous and thin. The key ratios governing packing patterns and eccentricity are number of cells per unit length λ and cell tension ratio Γ. By analyzing simulations that vary Γ and total number of cells N, we find that eccentricity, λ, and internal pressure approach consistent asymptotic values away from the tapering ends, as N increases. The length of the tapering ends is quantified as a function of Γ and pattern. Formulas are derived for geometric ratios, pressure, and energy as functions of Γ and pattern. These observations on the relationship between mechanics, geometry, and pattern provide a framework for further work which may provide insight into the roles of mechanosensing and pressure-volume regulation in the notochord.