Research 

Mechanical set-up: the cell and ECM (both Kelvin-Voigt viscoelastics), connected by adhesions.

I study how cells sense and respond to their physical and biochemical environment. My work focuses on the formation and maturation of stress fibres and focal adhesions, key structures that link the cytoskeleton to the extracellular matrix and influence cell shape, signalling, and function. Using bio-chemo-mechanical models, I couple intracellular protein dynamics with a viscoelastic description of the cell and its surroundings. These models reproduce key experimental observations (e.g. non-uniform stress fibre striation patterns and the effect of substrate stiffness) and provide a predictive framework for understanding how cellular mechanics and biochemistry interact to drive behaviour in vitro.

Publications: G. R. McNicol, M. J. Dalby, and P. S. Stewart, A theoretical model for focal adhesion and cytoskeleton formation in non-motile cells in Journal of Theoretical Biology (2025).

Submitted: G. R. McNicol and P. S. Stewart, A mathematical framework for coupled mechanics and mechanosensing in adherent cells, Journal of Mathematical Biology (available upon request).

In preparation: G. R. McNicol and P. S. Stewart, An open-source computational framework for coupled viscoelastic and biochemical systems.

I study how flexible biological structures interact with flowing fluids, which can lead to self-excited oscillations. These phenomena have physiological relevance, including blood-pressure measurement (Korotkoff sounds) and airflow past the vocal cords. Using a combined analytical and numerical approach, I model flow through channels with flexible, tensioned walls of finite mass, identifying the conditions that trigger oscillations and showing how wall mass alters these instability mechanisms. These models also reveal how interactions between instability modes can lead to transient amplification of flow energy, providing insight into complex fluid-structure behaviour in physiological systems.

Submitted: G. R. McNicol and P. S. Stewart, Self-excited oscillations in a finite-length collapsible channel flow with a heavy wall (available upon request).

In preparation: G. R. McNicol and P. S. Stewart, Fluid-structure interaction in channels dominated by wall inertia.

Methane production in soils is balanced by microbial oxidation, and emissions are controlled by diffusion, plant-mediated transport, and ebullition (bubble release) pathways.

Wetlands are significant natural sources of greenhouse gases, particularly methane. I study how these emissions respond to environmental conditions such as temperature, water level, and available organic material. Using reduced, mechanistic models, I can to investigate how climate change or site-specific management strategies can affect greenhouse gas emissions.

Submitted: G. R. McNicol, A. T. Layton, and N. B. Basu, Understanding the balance between methane production and oxidation from wetlands: insights from a reduced process-based model (available upon request).

Schematic showing a four-compartment model for human nitrate and nitrite metabolism.

I study how dietary and waterborne nitrate and nitrite impact human health, focusing on their potential contribution to gastric and other cancer risks. Using reduced, mechanistic quantitative systems pharmacology models of nitrate-nitrite metabolism and gastric chemistry (including vitamin C inhibition of nitrosation), I predict N-nitroso compound formation under varying dietary conditions and identify strategies to reduce nitrosation. This is part of a broader framework to evaluate the balance between potential harms and the beneficial roles of nitrate in nitric-oxide signalling, vasodilation, and blood-pressure regulation.

Submitted: G. R. McNicol, N. B. Basu, and A. T. Layton, Vitamin C as a nitrosation inhibitor: a modelling study across dietary patterns and water quality (available upon request).

In preparation: G. R. McNicol, N. B. Basu, and A. T. Layton, Population heterogeneity in gastric nitrosation: implications for dietary and waterborne nitrate-nitrite exposures.