Upcoming Postdoc Seminars
All seminars will be held in the MBI Lecture Hall - Jennings Hall, Room 355 - unless otherwise noted.
Oncolytic virotherapy is a tumor treatment which uses viruses to selectively target and destroy cancer cells. Clinical trials have demonstrated varying degrees of success for the therapy with limitations predominantly due to barriers to viral spread throughout the tumor and the immune response to the virus.
Fusogenic viruses, capable of causing cell-to-cell fusion upon infection of a tumor cell, have shown promise as oncolytic agents in experimental studies. The fusion causes the formation of multinucleated syncytia which enhances viral spread through the tumor and eventually leads to cell death. We formulate a partial differential equations model with a moving boundary to describe the treatment of a spherical tumor with a fusogenic oncolytic virus. In this talk, I will discuss the existence and uniqueness of local solutions to the nonlinear hyperbolic-parabolic system. In a special case, a reduction to an ordinary differential equations system allows for a global stability analysis which provides a prediction of success or failure of the treatment. Numerical simulations demonstrate exponential growth or decay of the tumor depending on viral burst size and rate of syncytia formation.
I will also briefly discuss work in progress on modeling the upregulation of the matricellular protein CCN1 in oncolytic virotherapy of glioma. Overexpression of CCN1 has been shown experimentally to induce an antiviral immune response including the proinflammatory activation of macrophages. Understanding the interactions between the tumor, virus and immune response is critical to improving the efficacy of virotherapy.
Extirpation of vertebrates by human activity results in "empty forests", with disrupted ecological processes, including seed dispersal of plants. Although seed dispersal is typically modeled as monotonically decreasing with distance from the tree, vertebrates disperse seeds in clumps to preferred areas. These seeds must survive the attack of insect seed predators in order to germinate, and clumped seed deposition can greatly alter the number and spatial distribution of germinating plants. I will show how the interaction between seed dispersal by vertebrates and patterns of plant mortality due to insect seed predators shapes the spatial pattern of seed survivorship, and use individual-based models to examine how dispersal disruption modifies these patterns. This basic understanding will help us predict the future of plant communities faced by anthropogenic pressures that include the hunting of seed dispersers.
During forward swimming of crayfish, four pairs of limbs called swimmerets swing rhythmically through power and return strokes. Neighboring limbs move in a back to front metachronal wave with a delay of approximately 25% of the period. Interestingly, this posterior to anterior progression is maintained over the entire range of behaviorally relevant stroke frequencies. Previous work has modeled the neural circuitry coordinating this motion as a chain of nearest neighbor coupled oscillators, and it was shown that the architecture of this circuitry could provide a robust mechanism for this behavior. However, this study ignored the presence of weaker longer range coupling between oscillators, and how the coupling affects this mechanism is unknown.
In this talk, I will discuss the role of the long range coupling in the swimmeret system. An analytical argument using a phase model suggests that the presence of long range coupling speeds up the metachronal wave when the connection strength is sufficiently weak. Numerical simulations show that this effect extends to larger connection strengths. Further, we confirm these predictions in a more detailed conductance-based neuronal model. Finally, we verify the validity of the model by comparing results from the phase model to experiments that probe the effects of long range coupling.
Combined with results from a computational fluid dynamics model, our findings indicate that the long range coupling might exist to ensure that the crayfish’s limb movement during forward swimming is in an optimally efficient regime.
Abstract coming soon.
Upcoming Visitor Seminars
The folding pattern of the human brain has many ridges (gyri) and valleys (sulci), making it difficult to visualize and analyze. The development of these folding patterns is not fully understood and there is debate in the biological and neuroscientific communities as to why folds develop in a particular location. Additionally, there are many diseases involving the folding the patterns of the brain that occur in early development and causes of these diseases are not understood. I will discuss some mathematical and computational models we have developed using a prolate spheroid domain to gain insight into cortical folding pattern formation. I will also discuss how conformal mapping and topology can assist with the study and analysis of diseases in the human brain.