Topological magnetohydrodynamics and and the dynamics of anti-cancer immunotherapy

This will be a joint seminar held in the School's AGR (Carslaw 829) between Kyushu University and the University of Sydney. The aim of the seminar is to foster the exchange of ideas and possibly collaborations between our two schools.

There will be two talks:

• 9:30-10:30 Yasuhide Fukumoto (Kyushu), Topological magnetohydrodynamics and its application to azimuthal magnetorotational instability
• 10:30-11:30 Peter Kim (Sydney), Modelling dynamics of anti-cancer virotherapy and immunotherapy

Abstracts appear below.

Everyone is encouraged to attend.

Andrew

 

Abstract for Yasuhide Fukumoto's talk
Magnetorotational instability (MRI) discovered by Velikhov (1959) and Chandrasekar (1960) has attracted attention since Balbus and Hawley ( 1991) pointed out that the MRI can trigger turbulence necessary to account for outwards transport of the angular momentum, while forming a star in the center, in the accretion disks.

A global modal analysis is made of axisymmetric rotating flows of an electrically conducting fluid subjected to external azimuthal (=toroidal) magnetic field. This instability of the MHD is referred to as the azimuthal magnetorotational instability (AMRI). The analysis is limited to a rigidly rotating flow subjected to the azimuthal magnetic field with its strength proportional to the distance from the axis of symmetry of an ideal MHD. We derive formulas for the MHD waves and highlight the viewpoint of the Hamiltonian spectra by calculating energy of waves.

Then a short-wavelength stability analysis is made of the AMRI with an arbitrary, though axisymmetric, distribution of flow velocity. Non-ideal effects, the viscosity and the magnetic diffusivity, are taken into account. Non-axisymmetric perturbations, when coupled to azimuthal magnetic field, makes unstable rotating flows of a wide variety of angular-velocity and magnetic-field profiles. We determine the range of the unstable profiles and the overall maximum growth rate for the AMRI.

Abstract for Peter Kim's talk
The year 2005 marked a clinical breakthrough for cancer treatment when the first oncolytic virus was approved for human use in China. This virus, called H101, was a genetically-engineered adenovirus produced by Shanghai Sunway Biotech for the treatment of head and neck cancer.

The appearance of H101 led to a rapid surge of interest in this novel approach to cancer treatment, which involves genetically-engineering viruses to preferentially infect and destroy tumour cells. These viruses also can induce concurrent anti-tumour immune responses, leading to complex and nonlinear cancer, virus, and immune interactions.

Several challenges that remain with oncolytic virotherapy are the rapid clearance of viruses by the host immune response before the tumour is eliminated, inhomogeneous and sparse dispersal of virus within a tumour, and toxicity due to accumulation of virus in the liver. In an effort to strategically improve and optimise virus development and treatment approaches, we seek to develop a dynamical framework for understanding the interactions among viruses, tumour cells, and immune cells over time.

Using recent experimental data collected for a strain of genetically-engineered oncolytic adenoviruses, we develop ordinary differential equation (ODE) models for several different treatments. After parameterising the models based on experimental data, we consider how treatment strategies can be modified to rapidly kill the tumour with a goal of complete elimination or maintain the tumour long-term at low levels. Finally, we describe the problem of improving the pharmacokinetic delivery of oncolytic virus into tumours.