Biophysics Seminar day - 3/30/2017 - 9:00am-11:30pm - 1080 Physics Research Building

9:00-10:00 Multiband imaging for functional and structural MRI
Essa Yacoub, University of Minnesota

Recent developments in multiband imaging have made its use highly attractive for both functional and diffusion imaging. Among these developments are improvements in image reconstructions as well as pulse sequence optimizations. The efforts have made 2D multiband EPI the standard for imaging projects and applications around the globe. Current efforts continue to push the acceleration potential of the multiband techniques for neuroscience applications looking to push the limits of either temporal or spatial resolution, or both.

10:30-11:30 The biophysics of bacterial biofilms: a basis for developing new solutions in healthcare and industry
Paul Stoodley, Departments of Microbial Infection and Immunity, Orthopaedics and Microbiology
Affiliate Professor Microbial Tribology, University of Southampton, UK

Bacterial biofilms are microscopic assemblages of bacterial cells usually attached to a surface and held together by a self-produced extracellular polymeric slime (EPS) matrix. Biofilms are ubiquitous in nature and are highly problematic in industry and medicine where they cause corrosion, fouling, contamination and chronic medical and dental infections. The EPS matrix is chemically complex and is composed of polysaccharides, lipids, proteins and DNA and protects the bacteria within from antibiotics chemical challenges and host immunity. Mass transfer through the EPS is dominated by diffusion which, allows the development of gradients in nutrients, waste products and cell signals. The highly localized and heterogeneous chemical microenvironment can be corrosive and cytotoxic and facilitates the development of dormant antibiotic tolerant populations. The bulk mechanical properties of biofilms also play a role in survival by allowing the biofilm to respond to imposed mechanical loads over very short (ms) and very long (days to weeks) time scales. Creep and relaxation tests show that generally biofilms behave as viscoelastic liquids however and recent observations of high velocity impacts with water droplets suggest they rapidly form interfacial instabilities allowing them to flow over surfaces with velocities of meters per second. However a better understanding of how bacterial biofilms respond and adapt to mechanical and antimicrobial stresses provides new opportunities to develop more effective therputics.

Last update: 3/15/2017, Ralf Bundschuh