Title: Image guided 1D fluid mechanics model for blood flow
Abstract: This study discusses the use of one-dimensional fluid dynamics models for prediction of flow, pressure, shear stress, and wave propagation in pulmonary vascular networks obtained from images. The model presented here includes predictions at multiple scales, including the large arteries and veins, arterioles and venules, and capillaries. The large arteries and veins are represented by a directed graph extracted from computed tomography images, whereas the network of arterioles and venules are represented by structured trees with parameters informed by data. The capillary network modeled using a sheet approximation, is coupled to the network of arterioles and veins in a ladderlike figuration. In the large vessels, we solve the 1D Navier Stokes equations, while in the network of small vessels and capillaries we solve linearized equations, which are coupled to large vessels via outflow boundary conditions. The model is calibrated to a healthy control, and we progressively increase disease severity via vessel stiffening and narrowing To differentiate healthy and diseased networks, we account for remodeling by altering vessel stiffness, vessel geometry (length and radius), and resistance provided by vessels in the microcirculation. This study addresses the importance of these features comparing hemodynamic predictions in healthy controls and control patients with disease.

Title: Identifiability and optimal control analysis of HIV infection and opioid addiction model.
Abstract: Based on the growing association between opioid addiction and HIV infection, a compartmental model is developed to study dynamics and optimal control of two epidemics: opioid addiction and HIV infection. We show that the disease-free-equilibrium is locally asymptotically stable when the basic reproduction number R_0= max 〖(R〗_(0 , )^u R_(0 )^v) 1 and it is locally asymptotically stable when the invasion number of the opioid addiction is R_(inv )^u 1 and it is locally asymptotically stable when the invasion number of the HIV infection is R_(inv )^v< 1. We study structural identifiability of the parameters, estimate parameters employing yearly reported data from Central for Disease Control and Prevention (CDC), and study practical identifiability of estimated parameters. We observe the basic reproduction number ¬¬¬¬R_0 using the parameters. Next, we introduce four distinct controls in the model for the sake of control approach, including treatment for addictions, health care education about not sharing syringes, highly active anti-retroviral therapy (HAART), and rehab treatment for opiate addicts who are HIV infected. US population using CDC data, first applying a single control in the model, and observing the results, we better understand the influence of individual control. After completing each of the four applications, we apply them together at the same time in the model and compare the outcomes using different control bounds and state variable weights. We conclude the results by presenting several graphs.

Title: Modeling the dynamics of Usutu virus infection in birds
Abstract: Nora Heitzman-Breen, Jacob Golden, Sarah C. Kuchinsky, Francesca Frere, Christa F. Honaker, Paul B. Siegel, Tanya LeRoith, Nisha K. Duggal, Stanca Ciupe Usutu virus is a mosquito-borne flavivirus maintained in wild bird populations, causing high avian mortality rates and occasional severe neurological disorders in humans. It has been hypothesized that increased Usutu virus replication in birds and/or decreased bird immune competence leads to increased mosquito infection and increased spillover in humans. To provide insight into the intrinsic complexity of host-virus processes in birds, we use within–host mathematical models to characterize the mechanisms responsible for virus expansion and clearance in juvenile chickens challenged with four Usutu virus strains. Several virus strains are co-circulating in the wild, and we find heterogeneity between the virus strains, with the time between cell infection and viral production varying between 16 h and 23 h, the infected cell lifespan varying between 48 min and 9.5 h, and the basic reproductive number varying between 12.05 and 19.49. The strains with high basic reproductive number have short infected cell lifespan, indicative of immune responses. The virus strains with low basic reproductive number have lower viral peaks and longer lasting viremia, due to lower infection rates and high infected cell lifespan. These results can be used to better determine which virus strain is the most likely to spillover in the human population. We also investigate the effect of antibody on virus dynamics by fitting the models to chickens that were genetically engineered to have low and high antibody count; and show that the viral clearance rate is a stronger mitigating factor for USUV viremia than neutralizing antibody response in this avian model.