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Events

The MSRC regularly hosts Colloquium talks and research conferences. In this academic year, they typically take place on Monday between 4-5 pm in MAPTC 0G/018,

Upcoming:

Date: 21 October 2024
Talk 1 (4-4:30)
Speaker: Emily Gribbin, MSRC, QUB
Title: "Capturing Fleeting Moments: Compound Moves in Reversible Jump MCMC for Changepoint Detection in Single Molecule Imaging"
Abstract:  "The development of non-small cell lung cancer is in part due to mutations in the DNA of Epidermal Growth Factor Receptor (EGFR) proteins, which can trigger unpredictable clustering of the EGFRs on the cell membrane. Analysing the spatial arrangement of these protein clusters can provide a better understanding of the underlying molecular processes leading to cancer development and aid in the development of treatments.

Fluorescence Localisation Imaging with Photobleaching (FLImP) (Iyer et. al., 2024) is a single molecule imaging technique which relies on the sequential photobleaching of fluorescent molecules, known as fluorophores, bound to the EGFRs on the cell surface. This photobleaching creates a staircase-like pattern in the one-dimensional fluorophore intensity profiles, as the fluorophores turn off one-by-one. Each FLImP dataset comprises of millions of these one-dimensional intensity profiles but, using the current approach, only a small fraction will be suitable for further analysis. This is in part due to fluorophores displaying complex bleaching profiles whereby they experience short-lived ‘off’ states, known as blink[1]events and longer-lived temporary ‘dark-states’. By considering the number and locations of these photobleach and ‘off’ state events as a changepoint problem, we can estimate the number of fluorophores active in each frame.

The research presented outlines the use of reversible jump Markov chain Monte Carlo for changepoint detection to model the number of active fluorophores in each frame (Green, 1995). We introduce compound moves to better capture the short-lived ‘off’ states, often overlooked using traditional methods. Using a simulation study and application to one-dimensional FLImP data, we demonstrate that the introduction of compound moves allows complex bleaching profiles to be accurately modelled and enables a larger number of FLImP tracks to be used for downstream processing."

Talk 2 (4:30-5)
Speaker: Ana Bensabat, Coimbra University
Title: "Mathematical Influences of Cell Substrate on Migration & Deformation"
Abstract: "Cell migration and deformation play key roles in several physiological and pathological processes. The underlying substrate influences both the cell mobility and cell shape. Endothelial cells cover the interior of blood vessels and their elongated form prevents the formation of atherosclerotic lesions. In this work, 
we present a phase field model for the deformation of endothelial cells on a micro-grooved substrate and the conditions of nucleus entrapment in the grooves (caging) are studied. We introduce a non-local term that prevents the cell domain from splitting in conditions of high adhesion and curvature. Our numerical simulations show that the main driver of nucleus caging is the cell-substrate adhesion. Caging occurs for high adhesions and for nuclei with rigidities close to or inferior to that of the cell. We further verified that the geometry of the grooved substrate is determinant in the caging processes. Deeper and shallower grooves are more favorable to nucleus penetration and caging. These findings are in agreement with 
experimental results found in the literature."