Research

September 2005

September 29, 2005

Beta-lactoglobulin aggregation visualized by AFM

Posted by Xianglan He

Afm28 10Um 1-3

This is an image of ß-Amyloid fibrils derived from ß-lactoglobulin taken using tapping-mode AFM in air on a piece of mica that has been chemically modified to bind our sample. Note the great diversity of size, shape, and height of the species present. Many different types of aggregates are visible in this image including filaments, fibrils, and small aggregates of various sizes.

September 4, 2005

Hidden Markov Models for Diffusive Processes

Posted by David Talaga

Diffusion Hmm-1

The top panel (a) shows a Monte Carlo simulated trajectory of a molecule diffusing through a spherically symmetric Gaussian collection volume. The next panel (b) shows the reciprocal of the inter-photon time. The delay between excitation and emission of the photon is the lifetime and is shown in panel (c). Panels (b) and (c) are used with three dimensional diffusion of the molecule through the focus of the instrument as the hidden Markov model to reconstruct the Brownian motion trajectory in panel (d). The trajectory was reconstructed by using Monte Carlo sampling of the HMM parameters to maximize the likelihood of the data in (b) and (c).