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Current Research by COSI Students

Event Details

Event Dates: 

Monday, October 8, 2012 - 10:00am

Speaker Name(s): 

Anthony Barsic, Joanna Duncan, Darren Forman

Speaker Affiliation(s): 

COSI Students, CU, Boulder
Seminar Type/Subject

Event Details & Abstract: 

 Anthony Barsic - COSI Fellow - ECEE“Superresolution of Dense Nanoscale Emitters Beyond the Diffraction Limit Using Spatial and Temporal Information”We propose a superresolution technique to resolve dense clusters of blinking emitters. The method relies on two basic assumptions: the emitters are statistically independent, and a model of the imaging system is known. We numerically analyze the performance limits of the method as a function of the emitter density and the noise level. Numerical simulations show that five closely packed emitters can be resolved and localized to a precision of 17nm. The experimental resolution of five quantum dots located within a diffraction limited spot confirms the applicability of this approach.Joanna Duncann - COSI Fellow – Chem. And Biochem.“Structural Variation within the Ventral Disc of Giardia Lamblia” Giardia lamblia has a unique microtubule cytoskeleton, including the ventral disc, which is critical for pathogenesis. The ventral disc is composed of a large spiral array of ~50 regularly spaced microtubules with microribbon structures that extend towards the dorsal surface of the cell, perpendicular to the microtubules.The disc contains a number of structurally distinct regions that can be easily identified in a transmission electron micrograph. These regions are the overlap zone, where the spiral continues under itself, the very edge of the disc periphery, which we term the margin, and the main body of the spiral, which we term inner microtubules.Previous work using cryo-electron tomography and 3D subvolume averaging of the inner microtubules has revealed novel protein densities and fine structures. Using these same techniques, we have obtained 3D volumes from the margin and both surfaces of the overlap zone. This work has revealed a surprising amount variation in fine-structural detail between these regions. Most divergent are the spacing of the microtubules, the angle, arrangement and composition of the microribbons and the number and arrangement of microtubule associated proteins or complexes, positioned along the microtubule.This work reveals variation that was not detected by other microscopy methods. It not only demonstrates the power of these techniques, but brings to light many interesting questions about the contribution of these regions and fine structures to the overall function of the disc and the methods by which such a complicated array is assembled and regulated.Darren Forman - COSI Fellow – ECEE“Developments in photo-inhibited super-resolution (PINSR) lithography” A novel optical lithography technique that combines unusual radical-photochemistry with concepts from STED microscopy, photo-inhibited super-resolution (PINSR) lithography promises optical patterning at resolutions far better than the diffraction limit. In this talk, I will discuss progress to date: findings, frustrations and surprises.