Research

INTERESTS
Modeling of regulation in cardiovascular and pulmonary systems
Differential equations and dynamical systems
Data-driven patient-specific parameterization
Numerical methods and optimization in physiological systems
Algorithm development for biomedical applications
Computational fluid dynamics

GRANTS AND AWARDS

Seed Award (VCU) Apr 2024 Predictive Modeling of Cerebrovascular Reactivity. PI: Laura Ellwein Fix. Award: $5000 for student stipend and travel.

Faculty Council Research Award, College of Humanities and Sciences (VCU) May 2016 Computational Modeling of Chest wall Rigidity. PI: Laura Ellwein Fix, PhD.

Atlantic Pediatric Device Consortium, 5^th Annual Innovation Competition Award. Oct 2015
Improving Chest Wall Rigidity in Very Preterm Infants. Co-PIs: Ku and Boyan. FDA #5P50FD004193-07, subaward GIT-RE159 to Henry Rozycki. Consultant: $3000.

ONGOING PROJECTS (current collaboration opportunities marked by )
Interested in the Systems Modeling and Analysis PhD program? Apply by Feb. 1 for the following academic year. Admissions are done centrally but you may express interest in particular faculty or projects.

Evaluation of Factors in Compromised Breathing in Preterm Infants using Pulmonary Dynamics Modeling
Henry Rozycki MD; Joseph E. Khoury, MD; Russell Moore, MD; Matthew Brandes, PhD (MCV).
Bradford Smith, PhD (CU-Anschutz).
Students: Richard Foster, Jeffrey Evans, Lauren Linkous

Non-invasive ventilation is increasingly used for respiratory support in preterm infants, and
is associated with a lower risk of chronic lung disease. However, this mode is often not successful
in the extremely preterm infant in part due to the highly compliant (floppy) chest wall at this stage of gestation. A foundational model parameterized for an idealized preterm infant was developed to show the effect of high chest wall compliance on progressive lung volume loss. This earliest work was published in PLoS One in 2018.
We recently developed a submodel of ribcage / abdominal mechanics to model thoracoabdominal asynchrony, or TAA (also called “chest retractions”). This work was published in AJP – Lung Cellular and Molecular Physiology in June 2023.
We extended the foundational model to a data set from rat pups as part of the 2023 Collaborative Workshop for Women in Mathematical Biology. This work was published in the Springer Volume
titled Mathematical Modeling for Women’s Health – Collaborative Workshop for Women in Mathematical Biology in 2024.
The parameter space contributing to dynamics observed in the foundational model was analyzed in work published in 2025 in Royal Society Philosophical Transactions A.
Recent efforts are focused on a bifurcation analysis related to the model’s mechanical parameters. Possible additional opportunities include:
- Incorporation of neural control as driver of model
- Addition of gas transport and chemoreflex response to breathing alterations
- Model effects of high frequency oscillation ventilation and/or high flow nasal cannula
- Addition of stochastic components

Modeling Cerebrovascular Reactivity in a Computer Model of Cardiorespiratory Dynamics
Students: Helen Harris, Mariana Fernandes Gragnani

Cardiovascular disease and impaired cerebrovascular reactivity is often associated with impaired regulatory processes, but their interaction is not well understood. The goal of this project is to create a computer model of blood vessel resistance in the brain (cerebrovascular resistance, or CVR) that functionally depends on blood gas levels and blood pressure. This is an extension of published work from 2013 in which an empirical piecewise model of CVR was created within an existing closed-loop compartment model of the whole body circulatory system. Current efforts focus on developing an open-loop model dependent on blood pressure and gas levels based on previously published studies, and incorporate within the closed-loop whole body circulation model framework.
This model is parameterized with continuous blood pressure, middle cerebral artery blood flow velocity, and expiratory CO2. This data is widely available for adults and we aim to incorporate such data in future studies to compare dynamics between groups of interest.

Mathematical Modeling of Fluid Dynamics in an ECMO Oxygenator
Oliver Karam, MD/PhD (Yale University)

Extracorporeal Membrane Oxygenation (ECMO) is a life-saving procedure providing cardiac and respiratory support to patients with severe and potentially fatal heart or lung conditions. However, the possibility of clot formation within the oxygenator, a crucial component of the ECMO system, remains a significant concern. We are beginning to explore the development of a mathematical model of the fluid dynamics in an ECMO oxygenator to eventually predict personalized clotting risk in patients.

Designing a Novel Hypothalamic-Pituitary-Adrenal Axis Sensor System and Mathematical Modeling for Clinical Applications.
Benjamin Nicholson MD, David Chan, Ed Acevedo
Student: Helen Harris

The overall project goal is to develop a novel artificial adrenal system that incorporates a multi-analyte sensor system, a mathematical model for interpreting these hormones, and a hormone augmentation system to evaluate four hormones (cortisol, adrenocorticotropic hormone, epinephrine, and norepinephrine) during acute shock. The first manuscript from this project was reccently accept for publication in March 2026 in PLoS One.

Collaborative Research: A National Consortium for Synergistic Undergraduate Mathematics via Multi-Institutional Interdisciplinary Teaching Partnerships.
Multiple institutions. Rebecca Segal, Vennie Filippas, Hilary Clark (VCU).

The overall project goal is to develop sustainable inter-institutional and inter-departmental collaborations that lead to improved outcomes in student transfer of knowledge from Mathematics to the partner discipline. Primary focus is on introductory Differential Equations.

Evaluation of Wall Shear Stress for Investigation of Restenosis in Stented Coronary Arteries Reconstructed Using Optical Coherence.
John F. LaDisa, Jr., Marquette University; Hiromasa Otake MD, Kobe University Graduate School.
Students: Ali Aleiou, Joshua Hughey

The success of drug eluting stents is limited by restenosis and late stent thrombosis. Stenting as a common intervention alters artery geometry, exposing an artery to adverse wall shear stress (WSS). For DES it is not conclusively known if optimizing WSS leads to clinical benefits. The objective of this study is to determine the relationship between DES-induced WSS indices and two markers of poor outcomes, change in lumen area and category of stent malapposition.

PAST PROJECTS

Fluid dynamics analysis of pulmonary vasculature for understanding pulmonary arterial hypertension.
Mette Olufsen, NCSU; Umar Qureshi (postdoc), NCSU; Naomi Chesler, UC-Irvine; Nick Hill, University of Glasgow.
Student: Mitchel Colebank

Translating Near Infrared Spectrocopy Oxygen Saturation Data for the Noninvasive Prediction of Spatial and Temporal Hemodynamics during Exercise.
John F. LaDisa, Jr., Sheila Schindler-Ivens, and Michael Danduran, Marquette University; Margaret Samyn, Children’s Hospital of Wisconsin.

Image-based Quantification Workflow for Coronary Morphology.
John F. LaDisa, Jr., Marquette University; Raymond Migrino, VA Health Care System (Phoenix); David Marks, Medical College of Wisconsin.

Modeling Autoregulation in the Kidney.
Anita Layton, Duke; Julia Arciero, IUPUI; Ashlee Ford Versypt, University of Buffalo.

Cardiovascular and Respiratory Regulation, Modeling and Parameter Estimation. PhD Thesis.
Advisor: Mette Olufsen, NCSU.