# Research

## Complex Systems: Mathematics, Computation & Science

### Monday, April 19, 2004

Title: Vascular Dynamics of the Central Nervous System: Macro- and Micro-circulation
Speaker: Apurva Bhatty
Time: 2:00pm–3:00pm
Place: LIF 267

#### Abstract

Cardiovascular dynamics has been modeled at many scales: from the computational fluid dynamics approach at the smallest scales of fluid flow within the vasculature to the lumped parameter simplified circuits at the larger scale of system dynamics.

The parameter values of such a circuit including the cerebro-vacular system may be derived from MRI images and from invasive and noninvasive clinical means. An approach combining $$4$$th order Runge-Kutta simulation of the macro and microcirculation with cellular-automata-like diffusion modeling of metabolites within the microcirculation will be described along with clinical and research applications of this approach in the surgical operating theater and in aviation and space medicine.

### Monday, March 15, 2004

Title: Competition in host-parasitoid systems
Speaker: Gary Huxel, Biology Department, USF
Time: 2:00pm–3:00pm
Place: LIF 267

#### Abstract

The Nicholson-Bailey host-parasitoid model system is inherently unstable. Factors such as spatial heterogeneity and density-dependent population growth can stabilize this system. However, the role of competition among both hosts and parasitoids in the N-B model system is largely unknown. We explore the consequences on stability and invasibility in low dimensional N-B model systems with multiple hosts and parasitoids.

### Monday, March 1, 2004

Title: Effects of turbulence on nutrient uptake by the benthos
Speaker: Florence Thomas, Biology Department, USF
Time: 2:00pm–3:00pm
Place: LIF 267

### Monday, February 16, 2004

Title: Bonds between Proteins and Carbohydrates: Directing molecular dynamics inside and outside cells
Speaker: Anna Plaas, Department of Internal Medicine, USF
Time: 2:00pm–3:00pm
Place: LIF 267

#### Abstract

The pivotal role of post-translational glycosylation of proteins for intracellular sorting, secretion, control of function and metabolic clearance, and modulation of protein/protein interactions involved in signal transduction pathways, is well-documented. Thus, structure-function data of N- and O-linked oligosaccharides is now generally incorporated into proteomic and metabolomic thinking and experimentation.

The biological importance of another type of protein-carbohydrate bonding, the non-covalent association of polysaccharides, glycosaminoglycans (GAGs), with many extracellular proteins, including growth factors and morphogens (FGF, HGF, chemokines, wnts), matrix proteins (collagen, fibronectin, link glycoprotein), enzymes (lipoprotein lipase, aggrecanase) and transmembrane proteins (CD44, HARE) has recently drawn much research attention. These interactions are usually multivalent, and an increasing number of complimentary amino acid and monosaccharide sequences are being elucidated. They serve to regulate intracellular signal output of receptor tyrosine kinases and extracellular modification of storage, diffusion and concentration of protein effectors. In addition, multi-component processes of cell-cell and cell-matrix interactions in epithelial-mesenchymal transition in development and in malignancy have also been shown to be critically dependant on the presence of GAG-protein interactions.