Mette Olufsen

Works (82)

Updated: September 3rd, 2024 08:23

2024 article

Application and reduction of a nonlinear hyperelastic wall model capturing ex vivo relationships between fluid pressure, area, and wall thickness in normal and hypertensive murine left pulmonary arteries

Haider, M. A., Pearce, K. J., Chesler, N. C., Hill, N. A., & Olufsen, M. S. (2024, January 12). INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Vol. 1.

By: M. Haider n, K. Pearce n, N. Chesler*, N. Hill* & M. Olufsen n

author keywords: arterial wall; hyperelastic pressure-area relation; hypoxia; identifiability; model reduction; pulmonary hypertension; sensitivity analysis
TL;DR: A novel approach to formulating a reduced order nonlinear elastic structural wall model for a large pulmonary artery with potential impact on one-dimensional fluids network models of vessel wall remodeling in the presence of cardiovascular disease is introduced. (via Semantic Scholar)
Sources: Web Of Science, NC State University Libraries, ORCID
Added: January 22, 2024

2024 article

Characterization of differences in immune responses during bolus and continuous infusion endotoxin challenges using mathematical modelling

Windoloski, K. A., Janum, S., Berg, R. M. G., & Olufsen, M. S. (2024, March 11). EXPERIMENTAL PHYSIOLOGY.

By: K. Windoloski n, S. Janum*, R. Berg* & M. Olufsen n

author keywords: administration method; continuous infusion; cytokines; data analysis; endotoxin challenge; inflammation; mathematical modelling
Source: Web Of Science
Added: April 1, 2024

2024 review

Guidelines for mechanistic modeling and analysis in cardiovascular research

[Review of ]. AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 327(2), H473–H503.

author keywords: computational modeling; mathematical model; model calibration; quantitative biology; simulation
UN Sustainable Development Goal Categories
Source: Web Of Science
Added: August 26, 2024

2024 journal article

SECRET: Statistical Emulation for Computational Reverse Engineering and Translation with applications in healthcare

COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING, 430.

author keywords: Statistical emulation; Parameter inference; Uncertainty quantification; Computational fluid-dynamics; Personalised healthcare
Source: Web Of Science
Added: July 30, 2024

2024 journal article

The importance of incorporating ventricular-ventricular interaction (VVI) in the study of pulmonary hypertension

MATHEMATICAL BIOSCIENCES, 375.

By: A. Colunga n, B. Carlson* & M. Olufsen n

author keywords: Ventricular ventricular interaction; Computational modeling; Cardiovascular modeling; Pulmonary hypertension; Linearization
UN Sustainable Development Goal Categories
Source: Web Of Science
Added: July 30, 2024

2023 journal article

A topological data analysis study on murine pulmonary arterial trees with pulmonary hypertension

MATHEMATICAL BIOSCIENCES, 364.

By: M. Miller n, N. Johnston n, I. Livengood n, M. Spinelli n, R. Sazdanovic n & M. Olufsen n

author keywords: Pulmonary hypertension; Vascular remodeling; Image segmentation; Tree pruning; Strahler order; Persistent homology; Topological data analysis; TDA
TL;DR: This study analyzes the change in pulmonary arterial morphometry in the presence of HPH using novel methods from topological data analysis (TDA) and finds that HPH trees are stiffer than control trees but have more branches and a higher depth. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Sources: Web Of Science, NC State University Libraries
Added: January 2, 2024

2022 article

A computational study of aortic reconstruction in single ventricle patients

Taylor-LaPole, A. M., Colebank, M. J., Weigand, J. D., Olufsen, M. S., & Puelz, C. (2022, November 5). BIOMECHANICS AND MODELING IN MECHANOBIOLOGY, Vol. 11.

author keywords: Hypoplastic left heart syndrome; Fontan circulation; Double outlet right ventricle; Perfusion; Fluid mechanics; Simulation; Systemic circulation
MeSH headings : Humans; Adult; Fontan Procedure / methods; Hemodynamics; Magnetic Resonance Imaging; Hypoplastic Left Heart Syndrome; Aorta
TL;DR: This study combines the MRA, 4D-MRI, and pressure data with 1D fluid dynamics models to predict hemodynamics in the major systemic arteries, including the cerebral and gut vasculature, to study hypoplastic left heart syndrome patients. (via Semantic Scholar)
Sources: Web Of Science, ORCID, NC State University Libraries
Added: November 6, 2022

2022 article

Numerical predictions of shear stress and cyclic stretch in pulmonary hypertension due to left heart failure

Bartolo, M. A., Qureshi, M. U., Colebank, M. J., Chesler, N. C., & Olufsen, M. S. (2022, January 17). BIOMECHANICS AND MODELING IN MECHANOBIOLOGY, Vol. 1.

By: M. Bartolo n, M. Qureshi n, M. Colebank*, N. Chesler* & M. Olufsen n

author keywords: Pulmonary hypertension; Micro-circulation; Wall shear stress; Cyclic stretch; Left heart disease; Computational modeling; Pulse wave propagation
MeSH headings : Blood Pressure; Heart Failure / complications; Hemodynamics; Humans; Hypertension, Pulmonary; Pulmonary Artery
TL;DR: Using a computational fluid dynamics model of the human pulmonary arteries, arterioles, venules, and veins, this model predicts pressure, flow, shear stress, and cyclic stretch that providing a way to analyze and investigate hypotheses related to disease progression in the pulmonary circulation. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Sources: Web Of Science, ORCID, NC State University Libraries
Added: January 17, 2022

2022 journal article

Postural orthostatic tachycardia syndrome explained using a baroreflex response model

JOURNAL OF THE ROYAL SOCIETY INTERFACE, 19(193).

By: J. Geddes n, J. Ottesen*, J. Mehlsen* & M. Olufsen n

author keywords: POTS; baroreflex; autonomic dysfunction; head-up tilt; mathematical modelling
MeSH headings : Baroreflex / physiology; Blood Pressure / physiology; Heart Rate / physiology; Humans; Postural Orthostatic Tachycardia Syndrome; Posture / physiology
TL;DR: It is demonstrated that modulation of parameters characterizing BR sensitivity allows us to predict the persistent increase in HR and the low-frequency BP and HR oscillations observed in POTS patients and that it is possible to simulate patients with neuropathic and hyperadrenergic POTS. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Source: Web Of Science
Added: September 12, 2022

2021 journal article

A Mathematical Model of the Dynamics of Cytokine Expression and Human Immune Cell Activation in Response to the Pathogen Staphylococcus aureus

FRONTIERS IN CELLULAR AND INFECTION MICROBIOLOGY, 11.

By: K. Talaei*, S. Garan*, B. Quintela*, M. Olufsen n, J. Cho*, J. Jahansooz*, P. Bhullar*, E. Suen* ...

author keywords: cytokines; mathematical modeling; immune response; immune system; Staphycoccus aureus; cytokine response; cell activation
MeSH headings : Cytokines; Humans; Models, Theoretical; Staphylococcal Infections; Staphylococcus aureus; Tumor Necrosis Factor-alpha
TL;DR: Results show that the cellular activation and cytokine expression model characterizing septic conditions can predict ex vivo mechanisms in response to gram-negative and gram-positive bacteria. (via Semantic Scholar)
Source: Web Of Science
Added: December 13, 2021

2021 journal article

A multiscale model of vascular function in chronic thromboembolic pulmonary hypertension

AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, 321(2), H318–H338.

author keywords: hemodynamics; mathematical modeling; pulmonary circulation; pulmonary hypertension; wave propagation
MeSH headings : Angioplasty, Balloon; Chronic Disease; Hemodynamics; Humans; Hypertension, Pulmonary / diagnostic imaging; Hypertension, Pulmonary / etiology; Hypertension, Pulmonary / physiopathology; Hypertension, Pulmonary / therapy; Models, Cardiovascular; Models, Theoretical; Pulmonary Artery / diagnostic imaging; Pulmonary Artery / physiopathology; Pulmonary Embolism / complications; Pulmonary Embolism / diagnostic imaging; Pulmonary Embolism / physiopathology; Pulmonary Embolism / therapy
TL;DR: A multiscale, image-to-hemodynamics pipeline for BPA therapy planning for inoperable CTEPH patients is provided, providing an integrative, holistic tool for identifying optimal target lesions for treatment. (via Semantic Scholar)
Sources: Web Of Science, ORCID, NC State University Libraries
Added: July 28, 2021

2021 journal article

A physiological model of the inflammatory-thermal-pain-cardiovascular interactions during an endotoxin challenge

JOURNAL OF PHYSIOLOGY-LONDON, 599(5), 1459–1485.

author keywords: cardiovascular dynamics; immune response; mathematical modelling; parameter estimation; thermal regulation
MeSH headings : Endotoxins / toxicity; Humans; Inflammation; Inflammation Mediators; Male; Pain; Sepsis
TL;DR: An innovative mathematical model incorporating interaction pathways between inflammation and physiological processes observed in response to an endotoxin challenge is developed and revealed that a multimodal treatment combining several therapeutic strategies gives the best recovery outcome. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Source: Web Of Science
Added: March 8, 2021

2021 journal article

Classification of orthostatic intolerance through data analytics

MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING, 59(3), 621–632.

By: S. Gilmore n, J. Hart*, J. Geddes n, C. Olsen*, J. Mehlsen*, P. Gremaud n, M. Olufsen n

author keywords: Orthostatic intolerance; Syncope; Classification; Clustering; Machine learning
MeSH headings : Autonomic Nervous System; Blood Pressure; Data Science; Heart Rate; Humans; Orthostatic Intolerance / diagnosis; Syncope / diagnosis; Tilt-Table Test
TL;DR: This study uses machine learning to categorize patients with orthostatic intolerance and shows that machine learning can provide accurate classification of disease groups for 98% of patients and two subgroups within the control patients differentiated by their BP response. (via Semantic Scholar)
UN Sustainable Development Goal Categories
Source: Web Of Science
Added: March 8, 2021

2021 journal article

Global sensitivity analysis informed model reduction and selection applied to a Valsalva maneuver model

JOURNAL OF THEORETICAL BIOLOGY, 526.

MeSH headings : Bayes Theorem; Blood Pressure; Heart Rate; Valsalva Maneuver
TL;DR: This study compares four GSA methods based on Sobol' indices (SIs) quantifying the parameter influence on the difference between the model output and the heart rate data and shows that it is necessary to incorporate both the aortic and carotid regions to model the VM. (via Semantic Scholar)
Source: Web Of Science
Added: July 26, 2021

2020 journal article

Characterization of Blood Pressure and Heart Rate Oscillations of POTS Patients via Uniform Phase Empirical Mode Decomposition

IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, 67(11), 3016–3025.

By: J. Geddes n, J. Mehlsen* & M. Olufsen n

author keywords: Heart rate; Oscillators; Baroreflex; Blood pressure; Empirical mode decomposition; Measurement; Aging; Empirical mode decomposition (EMD); head-up tilt (HUT); postural orthostatic tachycardia syndrome (POTS); uniform phase empirical mode decomposition (UPEMD); clustering
MeSH headings : Baroreflex; Blood Pressure; Heart Rate; Humans; Postural Orthostatic Tachycardia Syndrome; Tilt-Table Test
TL;DR: The 0.1 Hz phase response and oscillation amplitude metrics provide new markers that can improve Postural Orthostatic Tachycardia Syndrome diagnostic augmenting the existing diagnosis protocol only analyzing the change in HR. (via Semantic Scholar)
Source: Web Of Science
Added: November 24, 2020

2020 journal article

Deep phenotyping of cardiac function in heart transplant patients using cardiovascular system models

JOURNAL OF PHYSIOLOGY-LONDON, 598(15), 3203–3222.

By: A. Colunga n, K. Kim*, N. Woodall n, T. Dardas*, J. Gennari*, M. Olufsen n, B. Carlson*

author keywords: computational physiology; heart transplant; patient-specific modeling; right heart catheterization
MeSH headings : Heart Failure; Heart Transplantation; Heart Ventricles; Humans; Models, Cardiovascular; Pulmonary Artery; Ventricular Function, Right
TL;DR: Right heart catheterization data from clinical records of heart transplant patients are used to identify patient‐specific models of the cardiovascular system, which represent a snapshot of cardiovascular function at a given post‐transplant recovery time point. (via Semantic Scholar)
Source: Web Of Science
Added: July 13, 2020

2020 journal article

Mechanistic model of hormonal contraception

PLOS COMPUTATIONAL BIOLOGY, 16(6).

By: A. Wright n, G. Fayad*, J. Selgrade n & M. Olufsen n

MeSH headings : Adult; Contraceptive Agents / therapeutic use; Estrogens / therapeutic use; Female; Follicle Stimulating Hormone / physiology; Hormonal Contraception; Humans; Hypothalamus / drug effects; Luteinizing Hormone / physiology; Menstrual Cycle / drug effects; Models, Biological; Ovary / drug effects; Pituitary Gland / drug effects; Progestins / therapeutic use
TL;DR: This new model predicts mean daily blood concentrations of key hormones during a contraceptive state achieved by administering progestins, synthetic estrogens, or a combined treatment, and shows that contraception can be achieved with synthetic estrogen, with progestin, and by combining the two hormones. (via Semantic Scholar)
Source: Web Of Science
Added: August 24, 2020

2020 journal article

Persistent instability in a nonhomogeneous delay differential equation system of the Valsalva maneuver

MATHEMATICAL BIOSCIENCES, 319.

By: E. Randall n, N. Randolph n & M. Olufsen n

author keywords: Nonautonomous delay differential equation; Transcritical bifurcation; Hopf bifurcation; Postural orthostatic tachycardia syndrome (POTS); Cardiovascular regulation
MeSH headings : Adult; Autonomic Nervous System / physiology; Autonomic Nervous System / physiopathology; Blood Pressure / physiology; Heart Rate / physiology; Humans; Models, Neurological; Models, Theoretical; Postural Orthostatic Tachycardia Syndrome / physiopathology; Valsalva Maneuver / physiology
TL;DR: Analysis of a nonlinear, nonautonomous, nonhomogeneous open-loop neurological control model describing the autonomic nervous system response to the Valsalva maneuver suggests that instability caused from overactive sympathetic signaling may result in autonomic dysfunction. (via Semantic Scholar)
Source: Web Of Science
Added: February 3, 2020

2020 journal article

Structural and hemodynamic properties of murine pulmonary arterial networks under hypoxia-induced pulmonary hypertension

PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART H-JOURNAL OF ENGINEERING IN MEDICINE, 234(11), 1312–1329.

By: M. Chambers n, M. Colebank n, M. Qureshi n, R. Clipp* & M. Olufsen n

author keywords: Pulmonary hypertension; fractal networks; image segmentation; center line extraction; one-dimensional fluid dynamics; Navier-Stokes equations
MeSH headings : Animals; Hemodynamics; Humans; Hypertension, Pulmonary / diagnostic imaging; Hypoxia; Mice; Models, Cardiovascular; Pulmonary Artery / diagnostic imaging; X-Ray Microtomography
TL;DR: This study demonstrates how to combine imaging data from microcomputed tomography images with hemodynamic pressure and flow waveforms from control and hypertensive mice to generate subject-specific arterial networks in which one-dimensional fluid dynamics modeling is used to predict blood Pressure and flow. (via Semantic Scholar)
Sources: Web Of Science, ORCID, NC State University Libraries
Added: August 31, 2020

2019 journal article

A model-based analysis of autonomic nervous function in response to the Valsalva maneuver

JOURNAL OF APPLIED PHYSIOLOGY, 127(5), 1386–1402.

author keywords: baroreflex mechanism; carotid and aortic baroreceptors; mathematical modeling; parameter estimation; sympathetic and parasympathetic activity
MeSH headings : Adolescent; Adult; Aged; Aged, 80 and over; Autonomic Nervous System / physiology; Baroreflex / physiology; Blood Pressure / physiology; Female; Heart Rate / physiology; Humans; Male; Models, Theoretical; Respiratory Sinus Arrhythmia / physiology; Valsalva Maneuver / physiology; Young Adult
TL;DR: A mathematical model that can predict sympathetic and parasympathetic dynamics and simulates various VM responses is introduced and, by combining indices and model predictions, the pathologies for 5 AD patients are studied. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Source: Web Of Science
Added: December 9, 2019

2019 journal article

Cardiovascular dynamics during head-up tilt assessed via pulsatile and non-pulsatile models

Journal of Mathematical Biology, 79(3), 987–1014.

By: N. Williams*, R. Brady*, S. Gilmore n, P. Gremaud n, H. Tran n, J. Ottesen*, J. Mehlsen*, M. Olufsen n

author keywords: Cardiovascular dynamics modeling; Head-up tilt; Pulsatile versus non-pulsatile modeling; Parameter estimation; Orthostatic intolerance
MeSH headings : Adult; Blood Pressure; Cardiac Output / physiology; Heart Rate; Hemodynamics; Humans; Male; Models, Cardiovascular; Pulsatile Flow; Supine Position; Tilt-Table Test; Vascular Resistance / physiology
TL;DR: It is shown that mathematical modeling can be used to predict changes in cardiac contractility, vascular resistance, and arterial compliance, quantities that cannot be measured but are useful to assess the system’s state. (via Semantic Scholar)
UN Sustainable Development Goal Categories
Sources: Web Of Science, NC State University Libraries, Crossref
Added: August 19, 2019

2019 article

Control theory in biology and medicine: Introduction to the special issue

Thomas, P. J., Olufsen, M., Sepulchre, R., Iglesias, P. A., Ijspeert, A., & Srinivasan, M. (2019, April). BIOLOGICAL CYBERNETICS, Vol. 113, pp. 1–6.

MeSH headings : Animals; Biology; Computer Simulation; Humans; Medicine; Models, Biological; Models, Theoretical; Systems Biology
TL;DR: This special issue presents tutorials and research articles by several of the participants in the MBI workshops on control theory in biology and medicine, including workshop on control and modulation of neuronal and motor systems. (via Semantic Scholar)
Source: Web Of Science
Added: April 2, 2019

2019 journal article

Influence of image segmentation on one-dimensional fluid dynamics predictions in the mouse pulmonary arteries

JOURNAL OF THE ROYAL SOCIETY INTERFACE, 16(159).

By: M. Colebank n, L. Paun*, M. Qureshi n, N. Chesler*, D. Husmeier*, M. Olufsen n, L. Fix

author keywords: haemodynamics; fluid dynamics; pulmonary circulation; uncertainty quantification; image segmentation
MeSH headings : Algorithms; Animals; Computer Simulation; Hemodynamics; Hypertension, Pulmonary / diagnostic imaging; Hypertension, Pulmonary / physiopathology; Male; Mice; Models, Cardiovascular; Pulmonary Artery / diagnostic imaging; Pulmonary Artery / physiopathology; X-Ray Microtomography
TL;DR: This study quantifies the variability of one-dimensional CFD predictions by propagating the uncertainty of network geometry and connectivity to blood pressure and flow predictions using multiple segmentations of a single, excised mouse lung. (via Semantic Scholar)
Sources: Web Of Science, ORCID, NC State University Libraries
Added: February 3, 2020

2019 journal article

Sensitivity analysis and uncertainty quantification of 1-D models of pulmonary hemodynamics in mice under control and hypertensive conditions

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, 37(11).

By: M. Colebank n, M. Qureshi n & M. Olufsen n

author keywords: computational fluid dynamics; network models; pulmonary hypertension; sensitivity analysis; uncertainty quantification
MeSH headings : Animals; Bayes Theorem; Hemodynamics; Mice; Pulmonary Artery; Uncertainty; X-Ray Microtomography
TL;DR: Results show that MPA pressure predictions are most sensitive to distal vascular resistance and that parameter influence changes with increasing network complexity, and suggest that PH leads to increased vascular stiffness and decreased peripheral compliance, congruent with clinical observations. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Sources: Web Of Science, ORCID, NC State University Libraries
Added: September 30, 2019

2018 article

An optimal control approach for blood pressure regulation during head-up tilt

Williams, N. D., Mehlsen, J., Tran, H. T., & Olufsen, M. S. (2019, April). BIOLOGICAL CYBERNETICS, Vol. 113, pp. 149–159.

By: N. Williams*, J. Mehlsen*, H. Tran n & M. Olufsen n

author keywords: Cardiovascular dynamics modeling; Head-up tilt; Non-pulsatile model; Orthostatic intolerance; Optimal control
MeSH headings : Blood Pressure / physiology; Cardiac Output / physiology; Heart Rate / physiology; Humans; Lower Extremity / physiology; Models, Cardiovascular; Nonlinear Dynamics; Posture / physiology; Tilt-Table Test; Vascular Resistance
TL;DR: Results show that the optimal control approach can predict time-varying quantities regulated by the cardiovascular control system, and shows the feasibility of using optimal control theory to compute physiological control variables, vascular resistance and cardiac contractility. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Sources: Web Of Science, NC State University Libraries
Added: April 2, 2019

2018 article

Cardiovascular regulation in response to multiple hemorrhages: analysis and parameter estimation

Ciocanel, M.-V., Docken, S. S., Gasper, R. E., Dean, C., Carlson, B. E., & Olufsen, M. S. (2019, April). BIOLOGICAL CYBERNETICS, Vol. 113, pp. 105–120.

author keywords: Blood withdrawal; Cardiovascular regulation; Mathematical modeling; Parameter estimation; Left ventricular volume; Left ventricular pressure
MeSH headings : Animals; Blood Pressure / physiology; Blood Volume / physiology; Cardiovascular System / physiopathology; Confidence Intervals; Hemorrhage / pathology; Hemorrhage / physiopathology; Male; Models, Cardiovascular; Models, Theoretical; Nonlinear Dynamics; Rats; Rats, Sprague-Dawley; Regional Blood Flow / physiology; Ventricular Function, Left
TL;DR: This is the first study to analyze the response to multiple blood withdrawals both experimentally and theoretically, and results show that during each blood withdrawal both systemic vascular resistance and contractility decrease acutely and partially recover, and they decrease chronically across the series of blood withdrawals. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Source: Web Of Science
Added: April 2, 2019

2018 journal article

Hemodynamic assessment of pulmonary hypertension in mice: a model-based analysis of the disease mechanism

Biomechanics and Modeling in Mechanobiology, 18(1), 219–243.

By: M. Qureshi n, M. Colebank n, L. Paun*, L. Ellwein Fix, N. Chesler*, M. Haider n, N. Hill*, D. Husmeier*, M. Olufsen n

author keywords: Pulmonary hypertension; 1D fluid dynamics model; Linear and nonlinear wall model; Parameter estimation; Statistical model selection; Wave intensity analysis; Impedance analysis
MeSH headings : Animals; Electric Impedance; Hemodynamics; Hypertension, Pulmonary / diagnostic imaging; Hypertension, Pulmonary / physiopathology; Male; Mice, Inbred C57BL; Models, Biological; Nonlinear Dynamics; Pressure; X-Ray Microtomography
TL;DR: Results show that pulmonary hypertension is associated with stiffer and less compliant proximal and distal vasculature with augmented wave reflections, and that elastic nonlinearities are insignificant in the hypertensive animal. (via Semantic Scholar)
Sources: Web Of Science, Crossref, NC State University Libraries, ORCID
Added: February 25, 2019

2018 journal article

MCMC methods for inference in a mathematical model of pulmonary circulation

Statistica Neerlandica, 72(3), 306–338.

author keywords: constraint non-linear optimization; delayed rejection adaptive metropolis; pulmonary hypertension; parameter inference; partial differential equations; Windkessel model
TL;DR: This study uses a fluid dynamics network model that takes selected parameter values and mimics the behaviour of the pulmonary haemodynamics under normal physiological and pathological conditions, and introduces an improved parameter scaling technique in the Delayed Rejection Adaptive Metropolis algorithm. (via Semantic Scholar)
Sources: Crossref, NC State University Libraries, ORCID
Added: July 1, 2019

2018 article

Parameter subset selection techniques for problems in mathematical biology

Olsen, C. H., Ottesen, J. T., Smith, R. C., & Olufsen, M. S. (2019, April). BIOLOGICAL CYBERNETICS, Vol. 113, pp. 121–138.

By: C. Olsen n, J. Ottesen*, R. Smith n & M. Olufsen n

author keywords: Parameter identifiability; Parameter subset selection; Parameter estimation; Modeling
MeSH headings : Algorithms; Blood Circulation; Blood Pressure; Computational Biology; Humans; Models, Biological; Models, Theoretical; Nonlinear Dynamics
TL;DR: This study demonstrates that methods based on local sensitivities are preferable in terms of computational cost and model fit when good initial parameter values are available, but that global methods should be considered when initial parameter value is not known or poorly understood. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (OpenAlex)
Sources: Web Of Science, NC State University Libraries
Added: April 2, 2019

2018 journal article

Personalized mathematical model of endotoxin-induced inflammatory responses in young men and associated changes in heart rate variability

Mathematical Modelling of Natural Phenomena, 13(5), 42.

Ed(s): K. Maruta, S. Minaev, N. Il Kim, H. Im & V. Gubernov

author keywords: Acute inflammation; mathematical modeling; heart rate variability; parameter estimation
TL;DR: The observed correlation between the inflammatory response and HRV brings us a step further towards understanding if HRV predictions can be used as a marker for inflammation, potentially translating to identifying a non-invasive marker that can be use to detect the onset of sepsis. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Sources: Web Of Science, NC State University Libraries, Crossref
Added: January 21, 2019

2018 journal article

Practical identifiability and uncertainty quantification of a pulsatile cardiovascular model

MATHEMATICAL BIOSCIENCES, 304, 9–24.

By: A. Marquis n, A. Arnold n, C. Dean-Bernhoft*, B. Carlson* & M. Olufsen n

author keywords: Cardiovascular dynamics; Modeling; Parameter estimation; Uncertainty quantification; Patient-specific modeling
MeSH headings : Animals; Female; Hemodynamics; Humans; Male; Models, Cardiovascular; Patient-Specific Modeling; Rats; Uncertainty
TL;DR: A novel workflow to calibrate a lumped-parameter model to left ventricular pressure and volume time series data and shows that it is possible to determine 5 identifiable model parameters that can be estimated to experimental data from three rats, and that computed UQ intervals capture the measurement and model error. (via Semantic Scholar)
Source: Web Of Science
Added: October 16, 2018

2017 journal article

Characteristic impedance: frequency or time domain approach?

Physiological Measurement, 39(1), 014004.

By: M. Qureshi n, M. Colebank n, D. Schreier*, D. Tabima*, M. Haider n, N. Chesler*, M. Olufsen n

author keywords: characteristic impedance; blood pressure and flow; pulse wave analysis; impedance analysis; time domain analysis; Fourier methods; large arteries
MeSH headings : Animals; Blood Pressure; Dogs; Electric Impedance; Heart / physiology; Hemodynamics; Humans; Mice; Pulse Wave Analysis; Signal-To-Noise Ratio; Time Factors
TL;DR: It is shown that the frequency and time domain estimates of Zc are not equally sensitive to certain characteristics of hemodynamic signals including phase lag between pressure and flow, signal to noise ratio and the end of systole retrograde flow. (via Semantic Scholar)
UN Sustainable Development Goal Categories
Sources: Web Of Science, Crossref, NC State University Libraries, ORCID
Added: August 6, 2018

2017 journal article

Increased blood pressure variability upon standing up improves reproducibility of cerebral autoregulation indices

MEDICAL ENGINEERING & PHYSICS, 47, 151–158.

author keywords: Cerebral autoregulation; Cerebral blood flow; Reproducibility; Variability
MeSH headings : Adult; Aged; Blood Flow Velocity / physiology; Blood Pressure / physiology; Blood Pressure Determination / methods; Cerebrovascular Circulation / physiology; Female; Homeostasis / physiology; Humans; Male; Patient Positioning / methods; Posture / physiology; Reproducibility of Results; Sensitivity and Specificity
TL;DR: Measurements taken immediately after standing up greatly improve the reproducibility of the autoregulation coefficients in the sit-to-stand manoeuvre, and this is generally coupled with an increase of the within-group spread of the estimates. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2017 journal article

Integrated Inflammatory Stress (ITIS) Model

BULLETIN OF MATHEMATICAL BIOLOGY, 79(7), 1487–1509.

author keywords: Mathematical modeling; Nonlinear ODE model; HPA axis; Acute inflammatory system; Immune system; Response to endotoxin (LPS)
MeSH headings : Adrenocorticotropic Hormone; Humans; Hydrocortisone; Hypothalamo-Hypophyseal System; Inflammation; Lipopolysaccharides; Models, Biological; Pituitary-Adrenal System
TL;DR: The ITIS model predicts that the most extensive response to an LPS injection in ACTH and cortisol concentrations is observed in the early hours of the day, which is the most pronounced result of different LPS doses predicted by the model. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2017 journal article

Uncertainty Quantification in a Patient-Specific One-Dimensional Arterial Network Model: EnKF-Based Inflow Estimator

Journal of Verification, Validation and Uncertainty Quantification, 2(1), 011002.

TL;DR: This study develops an iterative scheme based on the ensemble Kalman filter (EnKF) to estimate the temporal inflow profile from a prior distribution of curves and develops a measure of uncertainty in the size and shape of the estimated inflow, which is propagated through the model to determine the corresponding uncertainty in model predictions of area and pressure. (via Semantic Scholar)
Source: Crossref
Added: July 20, 2019

2016 journal article

Heterogeneous mechanics of the mouse pulmonary arterial network

BIOMECHANICS AND MODELING IN MECHANOBIOLOGY, 15(5), 1245–1261.

author keywords: Arterial blood flow; Vessel mechanics; Heterogeneity; Pulmonary arterial network; Pressure-radius relationship; Wave intensity analysis
MeSH headings : Animals; Biomechanical Phenomena; Blood Flow Velocity / physiology; Mice; Nonlinear Dynamics; Numerical Analysis, Computer-Assisted; Pressure; Pulmonary Artery / physiology; Reproducibility of Results; Stress, Mechanical
TL;DR: Simulations were conducted to investigate the role of linear versus nonlinear formulations of wall elasticity and homogeneous versus heterogeneous treatments of vessel wall properties, and Accounting for heterogeneity, by parameterizing the pressure/distention equation of state individually for each vessel segment was found to have little effect on the predicted pressure profiles and wave propagation. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2016 journal article

Modeling the differentiation of A- and C-type baroreceptor firing patterns

JOURNAL OF COMPUTATIONAL NEUROSCIENCE, 42(1), 11–30.

By: J. Sturdy*, J. Ottesen* & M. Olufsen n

author keywords: Baroreflex model; Mechanosensitivity; A- and C-type afferent baroreceptors; Biophysical model; Computational model
MeSH headings : Autonomic Nervous System Diseases / physiopathology; Humans; Models, Neurological; Neurons; Pressoreceptors; Synaptic Transmission
TL;DR: A comprehensive model of the afferent baroreceptor discharge built on physiological knowledge of arterial wall mechanics, firing rate responses to controlled pressure stimuli, and ion channel dynamics within the barorecept neurons is developed. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2016 journal article

Wave propagation in a 1D fluid dynamics model using pressure-area measurements from ovine arteries

Journal of Mechanics in Medicine and Biology, 16(02), 1650007.

By: C. Battista n, D. Bia*, Y. Germán, R. Armentano*, M. Haider n & M. Olufsen n

author keywords: Fluid mechanics; cardiovascular model; viscoelastic; arterial wall; arterial network
UN Sustainable Development Goal Categories
14. Life Below Water (OpenAlex)
Sources: Crossref, NC State University Libraries
Added: August 18, 2019

2015 journal article

Using Kalman Filtering to Predict Time-Varying Parameters in a Model Predicting Baroreflex Regulation During Head-Up Tilt

IEEE Transactions on Biomedical Engineering, 62(8), 1992–2000.

By: B. Matzuka n, J. Mehlsen*, H. Tran n & M. Olufsen n

author keywords: Baroreflex regulation; cardiovascular; DRAM; ensemble transform Kalman filter; head-up tilt; Kalman filtering; parameter estimation
MeSH headings : Algorithms; Baroreflex / physiology; Blood Pressure / physiology; Electrocardiography; Heart Rate / physiology; Humans; Male; Models, Cardiovascular; Posture / physiology; Signal Processing, Computer-Assisted
TL;DR: This study compares two methods predicting time-varying changes in cardiac contractility and vascular resistance during head-up tilt and shows that the ensemble transform Kalman filter (ETKF) has a significantly shorter computational time. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Sources: Web Of Science, Crossref, NC State University Libraries
Added: August 6, 2018

2014 journal article

Mathematical methods and models in system biomedicine

Mathematical Biosciences, 257, 1.

By: G. Pontrelli*, M. Olufsen n & J. Ottesen*

MeSH headings : Biomedical Research / methods; Humans; Models, Theoretical
TL;DR: This special issue includes a total of 12 manuscripts by leadingresearchers in mathematical biology discussing both modeling methodologies and applications tackling several aspects of multiscale problems with an exchange of information between theoretical and applied methods. (via Semantic Scholar)
Source: Crossref
Added: February 24, 2020

2014 journal article

Modeling Cerebral Blood Flow Velocity During Orthostatic Stress

Annals of Biomedical Engineering, 43(8), 1748–1758.

By: G. Mader n, M. Olufsen n & A. Mahdi*

author keywords: Cerebral autoregulation; Blood pressure; Structural identifiability; Practical identifiability; Viscoelasticity; Sensitivity analysis
MeSH headings : Animals; Blood Flow Velocity; Cerebrovascular Circulation; Humans; Models, Cardiovascular; Stress, Physiological
TL;DR: A simple, nonlinear quantitative model with only four parameters that can predict CBF velocity as a function of ABP is proposed and showed that the model is able to reproduce observed overshoot and adaptation and predict the different responses in the healthy young and the healthy elderly subject. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Source: Crossref
Added: July 20, 2019

2014 journal article

Numerical simulation of blood flow and pressure drop in the pulmonary arterial and venous circulation

BIOMECHANICS AND MODELING IN MECHANOBIOLOGY, 13(5), 1137–1154.

author keywords: Pulmonary circulation; Pulmonary hypertension; Resistance arteries; Structured tree; Multiscale mathematical model
MeSH headings : Blood Pressure / physiology; Humans; Hypertension, Pulmonary / physiopathology; Numerical Analysis, Computer-Assisted; Pulmonary Artery / physiopathology; Pulmonary Circulation; Pulmonary Veins / physiopathology
TL;DR: The results of simulating these pathological conditions are in agreement with clinical observations, showing that the model has potential for assisting with diagnosis and treatment for circulatory diseases within the lung. (via Semantic Scholar)
UN Sustainable Development Goal Categories
Source: Web Of Science
Added: August 6, 2018

2014 journal article

Structural correlation method for model reduction and practical estimation of patient specific parameters illustrated on heart rate regulation

MATHEMATICAL BIOSCIENCES, 257, 50–59.

By: J. Ottesen*, J. Mehlsen* & M. Olufsen n

author keywords: Parameter estimation; Inverse problems; Model reduction; Structural correlation method; Nonlinear heart rate model; Patient specific modeling
MeSH headings : Animals; Baroreflex / physiology; Heart Rate / physiology; Humans; Models, Biological
TL;DR: The model put forward by Bugenhagen et al. can be simplified without loss of its ability to predict measured data and to be interpreted physiologically, and it is shown that with minimal changes in nominal parameter values the simplified model can be adapted to predict observations from both rats and humans. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2013 journal article

Modeling the Afferent Dynamics of the Baroreflex Control System

PLoS Computational Biology, 9(12), e1003384.

By: A. Mahdi n, J. Sturdy n, J. Ottesen* & M. Olufsen n

Ed(s): J. Arciero

MeSH headings : Baroreflex / physiology; Humans; Models, Biological
TL;DR: The modeling framework for predicting baroreceptor firing rate as a function of blood pressure is developed and it is shown that nonlinear dependence of firing rate on pressure can be accounted for by taking into account the nonlinear elastic properties of the artery wall. (via Semantic Scholar)
Sources: Web Of Science, Crossref
Added: August 6, 2018

2013 journal article

Patient-specific modeling of cardiovascular and respiratory dynamics during hypercapnia

Mathematical Biosciences, 241(1), 56–74.

By: L. Ellwein*, S. Pope*, A. Xie*, J. Batzel*, C. Kelley n & M. Olufsen n

author keywords: Sensitivity analysis; Parameter estimation; Physiological models; Cerebral blood flow; Complex models
MeSH headings : Cerebrovascular Circulation; Heart Failure / physiopathology; Humans; Hypercapnia / physiopathology; Male; Mathematical Concepts; Middle Aged; Models, Biological; Models, Cardiovascular; Respiratory Physiological Phenomena; Vascular Resistance
TL;DR: A lumped cardiovascular-respiratory system-level model is developed that incorporates patient-specific data to predict cardiorespiratory response to hypercapnia (increased CO(2) partial pressure) for a patient with congestive heart failure (CHF). (via Semantic Scholar)
Sources: Web Of Science, Crossref
Added: August 6, 2018

2013 journal article

Patient-specific modelling of head-up tilt

MATHEMATICAL MEDICINE AND BIOLOGY-A JOURNAL OF THE IMA, 31(4), 365–392.

By: N. Williams n, O. Wind-Willassen*, A. Wright n, R. Program, J. Mehlsen*, J. Ottesen*, M. Olufsen n

author keywords: cardiovascular system dynamics; head-up tilt; sensitivity analysis; subset selection; parameter estimation
MeSH headings : Adult; Blood Pressure / physiology; Blood Volume / physiology; Cardiac Output / physiology; Heart Rate / physiology; Homeostasis / physiology; Humans; Male; Mathematical Concepts; Models, Cardiovascular; Myocardial Contraction / physiology; Posture / physiology; Supine Position / physiology; Tilt-Table Test; Vascular Resistance / physiology
TL;DR: A patient-specific model that uses heart rate as an input to fit the dynamic changes in arterial blood pressure data during HUT is presented, which estimates physiologically reasonable values for arterial and venous blood pressures, blood volumes and cardiac output for which data are not available. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2012 journal article

A practical approach to parameter estimation applied to model predicting heart rate regulation

JOURNAL OF MATHEMATICAL BIOLOGY, 67(1), 39–68.

By: M. Olufsen n & J. Ottesen*

author keywords: Parameter estimation; Inverse problems; Subset selection; Simulation and modeling; Nonlinear heart rate model; Medical applications; Patient specific modeling
MeSH headings : Baroreflex / physiology; Blood Pressure / physiology; Feedback, Physiological; Heart Rate / physiology; Humans; Mathematical Concepts; Models, Cardiovascular; Nonlinear Dynamics; Posture / physiology
TL;DR: Three methods that allow identification of parameter subsets that can be estimated given a model and a set of data are compared to estimate patient specific parameters in a model predicting baroreceptor feedback regulation of heart rate during head-up tilt. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2012 article

Development of Patient Specific Cardiovascular Models Predicting Dynamics in Response to Orthostatic Stress Challenges

MATHEMATICAL MODELING AND VALIDATION IN PHYSIOLOGY: APPLICATIONS TO THE CARDIOVASCULAR AND RESPIRATORY SYSTEMS, Vol. 2064, pp. 177–213.

By: J. Ottesen*, V. Novak* & M. Olufsen n

TL;DR: This study describes development of patient specific models, and how sensitivity analysis and nonlinear optimization methods can be used to predict patient specific characteristics when analyzed using experimental data. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2012 journal article

Impaired Cerebral Autoregulation Is Associated with Brain Atrophy and Worse Functional Status in Chronic Ischemic Stroke

PLOS ONE, 7(10).

TL;DR: The results indicate that better dynamic cerebral perfusion regulation is associated with less atrophy and better long-term functional status in older adults with chronic ischemic infarctions. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2012 journal article

Rarefaction and blood pressure in systemic and pulmonary arteries

JOURNAL OF FLUID MECHANICS, 705, 280–305.

By: M. Olufsen n, N. Hill*, G. Vaughan*, C. Sainsbury* & M. Johnson*

author keywords: blood flow
TL;DR: First theoretical calculations of the propagation of the pressure and flow waves along systemic and pulmonary large and small arteries are presented, showing that a decrease of compliance in the large arteries results in pressure increases consistent with observations of isolated systolic hypertension, as occurs in ageing. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2011 journal article

Linear and Nonlinear Viscoelastic Modeling of Aorta and Carotid Pressure-Area Dynamics Under In Vivo and Ex Vivo Conditions

ANNALS OF BIOMEDICAL ENGINEERING, 39(5), 1438–1456.

author keywords: Viscoelasticity; Nonlinear elasticity; Arterial wall properties; Thoracic descending aorta; Carotid artery; Mathematical modeling
MeSH headings : Animals; Aorta; Aorta, Thoracic / physiology; Blood Pressure / physiology; Carotid Arteries / physiology; Elasticity; Female; Humans; Male; Models, Cardiovascular; Sheep
TL;DR: This study demonstrates that the proposed models can predict pressure–area dynamics and that model parameters can be extracted for further interpretation of biomechanical properties and indicates that optimal model selection depends on the artery type. (via Semantic Scholar)
Sources: Web Of Science, NC State University Libraries
Added: August 6, 2018

2011 journal article

PREDICTING ARTERIAL FLOW AND PRESSURE DYNAMICS USING A 1D FLUID DYNAMICS MODEL WITH A VISCOELASTIC WALL

SIAM JOURNAL ON APPLIED MATHEMATICS, 71(4), 1123–1143.

By: B. Steele n, D. Valdez-Jasso*, M. Haider n & M. Olufsen n

author keywords: 1D fluid dynamics model; viscoelastic constitutive equation; systemic arteries; finite element analysis
TL;DR: This paper combines a generalized viscoelastic model with a one-dimensional (1D) fluid dynamics model for the prediction of blood flow, pressure, and vessel area in systemic arteries. (via Semantic Scholar)
UN Sustainable Development Goal Categories
Sources: Web Of Science, NC State University Libraries
Added: August 6, 2018

2011 conference paper

The impact of gravity during head-up tilt

2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2399–2402.

By: M. Olufsen n, B. Smith, J. Mehlsen & J. Ottesen

MeSH headings : Baroreflex / physiology; Blood Pressure / physiology; Blood Volume / physiology; Computer Simulation; Gravitation; Humans; Models, Cardiovascular; Tilt-Table Test / methods
TL;DR: It is shown, using a differential equations model predicting blood pressure, that it is possible to predict blood pressure measured at the level of the carotid sinuses using heart rate as an input. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (OpenAlex)
Source: NC State University Libraries
Added: August 6, 2018

2011 conference paper

Toward online, noninvasive, nonlinear assessment of cerebral autoregulation

2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2410–2413.

By: M. Aoi n, B. Matzuka n & M. Olufsen n

MeSH headings : Blood Flow Velocity; Blood Pressure; Brain / physiology; Cerebral Arteries / physiology; Cerebrovascular Circulation / physiology; Diagnosis, Computer-Assisted / methods; Feedback, Physiological; Humans; Models, Cardiovascular; Nonlinear Dynamics; Online Systems
TL;DR: This simulation study uses the EnKF to estimate the parameters of a model of cerebral hemodynamics which predicts intracranial pressure and cerebral blood flow velocity, generated from real patient arterial blood pressure measurements. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (OpenAlex)
Source: NC State University Libraries
Added: August 6, 2018

2010 journal article

Functionality of the baroreceptor nerves in heart rate regulation

COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE, 101(2), 208–219.

By: J. Ottesen* & M. Olufsen n

author keywords: Baroreceptor nerves; Nonlinear feedback mechanism; Medical applications; Nonlinear oscillations; Mathematical modeling; Heart rate control; Sit-to-stand; Head-up tilt
MeSH headings : Heart Rate / physiology; Humans; Pressoreceptors / physiology
TL;DR: The nonlinear afferent model is analyzed and it is shown that the coupled model is able to predict heart rate regulation using blood pressure data as an input. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Source: Web Of Science
Added: August 6, 2018

2010 article

Linear and Nonlinear Viscoelastic Modeling of Ovine Aortic Biomechanical Properties under in vivo and ex vivo Conditions

2010 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC), pp. 2634–2637.

By: D. Valdez-Jasso n, D. Bia, M. Haider*, Y. Zocalo, R. Armentano & M. Olufsen*

MeSH headings : Animals; Aorta, Thoracic / pathology; Biomechanical Phenomena; Blood Pressure; Elasticity; Linear Models; Male; Models, Cardiovascular; Models, Statistical; Models, Theoretical; Nonlinear Dynamics; Sheep, Domestic; Stress, Mechanical; Transducers; Viscosity
TL;DR: It is concluded that the sigmoid nonlinear viscoelastic model best describes the biomechanical properties of ovine large arteries under both experimental conditions considered in this study. (via Semantic Scholar)
UN Sustainable Development Goal Categories
Sources: Web Of Science, NC State University Libraries
Added: August 6, 2018

2009 journal article

ESTIMATION AND IDENTIFICATION OF PARAMETERS IN A LUMPED CEREBROVASCULAR MODEL

MATHEMATICAL BIOSCIENCES AND ENGINEERING, 6(1), 93–115.

By: S. Pope, L. Ellwein, C. Zapata, V. Novak, C. Kelley & M. Olufsen

author keywords: cardiovascular modeling; systemic resistance; cerebrovascular resistance; parameter estimation; sensitivity analysis; subset selection
MeSH headings : Adult; Aged; Blood Flow Velocity / physiology; Blood Pressure / physiology; Brain / blood supply; Brain / physiology; Cerebral Arteries / physiology; Cerebrovascular Circulation / physiology; Computer Simulation; Female; Humans; Male; Middle Aged; Models, Cardiovascular; Ventricular Function / physiology; Young Adult
TL;DR: The method discussed in this study provides a new methodology to extract clinical markers that cannot easily be assessed noninvasively by using nonlinear optimization combined with sensitivity analysis and subset selection. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2009 journal article

Viscoelastic models for passive arterial wall dynamics

Advances in Applied Mathematics & Mechanics, 1(2), 151–165.

By: D. Valdez-Jasso, H. Banks, M. Haider, D. Bia, Y. Zocalo, R. Armentano, M. Olufsen

Source: NC State University Libraries
Added: August 6, 2018

2008 journal article

Analysis of Viscoelastic Wall Properties in Ovine Arteries

IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, 56(2), 210–219.

By: D. Valdez-Jasso n, M. Haider n, H. Banks n, D. Santana*, Y. German, R. Armentano*, M. Olufsen n

author keywords: Arterial wall properties; data analysis; mathematical modeling; mechanics; parameter estimation; viscoelasticity
MeSH headings : Algorithms; Animals; Arteries / physiology; Biomechanical Phenomena / physiology; Blood Pressure; Elasticity; Equipment Design; Male; Models, Cardiovascular; Nonlinear Dynamics; Sensitivity and Specificity; Sheep; Signal Processing, Computer-Assisted; Viscosity
TL;DR: Results reveal that elastic properties in both models vary across locations (smaller arteries are stiffer than larger arteries), and show that for all locations, the inclusion of viscoelastic behavior is important to capture pressure-area dynamics. (via Semantic Scholar)
UN Sustainable Development Goal Categories
Sources: Web Of Science, NC State University Libraries
Added: August 6, 2018

2008 journal article

BLOOD FLOW IN THE CIRCLE OF WILLIS: MODELING AND CALIBRATION

MULTISCALE MODELING & SIMULATION, 7(2), 888–909.

By: K. Devault n, P. Gremaud*, V. Novak*, M. Olufsen*, G. Vernieres & P. Zhao

author keywords: blood flow; viscoelastic arteries; fluid-structure interaction; Kalman filtering
TL;DR: A numerical model based on one-dimensional balance laws and ad hoc zero-dimensional boundary conditions is tested against experimental data and demonstrates the viability of the proposed approach on the circle of Willis, a vital subnetwork of the cerebral vasculature. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2008 article

Introduction to the special issues: Short-term cardiovascular-respiratory control mechanisms

Batzel, J. J., Novak, V., Kappel, F., Olufsen, M. S., & Tran, H. T. (2008, March). CARDIOVASCULAR ENGINEERING, Vol. 8, pp. 1–4.

By: J. Batzel*, V. Novak*, F. Kappel*, M. Olufsen n & H. Tran n

MeSH headings : Animals; Cardiovascular Physiological Phenomena; Computer Simulation; Feedback / physiology; Humans; Models, Biological; Respiratory Physiological Phenomena
TL;DR: This and the following issue of Cardiovascular Engineering are special issues reflecting research discussed during an interdisciplinary focused workshop entitled Short-term Cardiovascular–Respiratory Control Mechanisms. (via Semantic Scholar)
Sources: Web Of Science, NC State University Libraries
Added: August 6, 2018

2008 journal article

Mathematical Modelling of the Systemic Circulation: investigating pressure and flow throughout the microcirculation

Artery Research, 2(3), 112.

By: G. Vaughan, M. Olufsen*, N. Hill & C. Sainsbury

Source: Crossref
Added: February 24, 2020

2008 journal article

Modeling heart rate regulation - Part II: Parameter identification and analysis

CARDIOVASCULAR ENGINEERING, 8(2), 109–119.

By: K. Fowler*, G. Gray* & M. Olufsen n

author keywords: derivative-free optimization; model based prediction of heart rate; sensitivity analysis
MeSH headings : Algorithms; Animals; Baroreflex / physiology; Blood Flow Velocity / physiology; Blood Pressure / physiology; Computer Simulation; Heart Rate / physiology; Humans; Models, Cardiovascular
TL;DR: This study compares the Nelder–Mead optimization method to two sampling methods: the implicit filtering method and a genetic algorithm and shows that these off-the-shelf optimization methods can work in conjunction with the heart rate model and provide reasonable parameter estimates with little algorithm tuning. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2007 journal article

Fractal network model for simulating abdominal and lower extremity blood flow during resting and exercise conditions

Computer Methods in Biomechanics and Biomedical Engineering, 10(1), 39–51.

By: B. Steele n, M. Olufsen n & C. Taylor*

MeSH headings : Abdomen / blood supply; Abdomen / physiology; Blood Flow Velocity / physiology; Blood Pressure / physiology; Computer Simulation; Humans; Leg / blood supply; Leg / physiology; Models, Cardiovascular; Physical Exertion / physiology; Rest / physiology
TL;DR: A one-dimensional (1D) fluid dynamic model that can predict blood flow and blood pressure during exercise using data collected at rest is presented and provides groundwork with which to predict the flow distributions in a network due to physiologic regulation. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (OpenAlex)
Source: Crossref
Added: July 20, 2019

2007 journal article

Modeling heart rate regulation - Part I: Sit-to-stand versus head-up tilt

CARDIOVASCULAR ENGINEERING, 8(2), 73–87.

By: M. Olufsen n, A. Alston n, H. Tran n, J. Ottesen & V. Novak*

author keywords: mathematical modeling; heart rate regulation; sensitivity analysis
MeSH headings : Aged; Baroreflex / physiology; Blood Pressure / physiology; Computer Simulation; Feedback, Physiological / physiology; Female; Head / physiology; Heart Rate / physiology; Humans; Male; Models, Cardiovascular; Posture / physiology; Tilt-Table Test / methods
TL;DR: During head-up tilt, the baseline firing-rate is larger than during sit-to-stand and that the combined effect of vestibular and central command stimulation of muscle sympathetic nerve activity is less pronounced than during sitting to standing. (via Semantic Scholar)
Sources: Web Of Science, NC State University Libraries
Added: August 6, 2018

2007 journal article

Sensitivity analysis and model assessment: Mathematical models for arterial blood flow and blood pressure

CARDIOVASCULAR ENGINEERING, 8(2), 94–108.

By: L. Ellwein n, H. Tran n, C. Zapata n, V. Novak n & M. Olufsen n

author keywords: cardiovascular modeling; sensitivity analysis; model reduction; parameter estimation
MeSH headings : Algorithms; Arteries / physiology; Blood Flow Velocity / physiology; Blood Pressure / physiology; Computer Simulation; Diagnosis, Computer-Assisted / methods; Models, Cardiovascular; Posture / physiology; Reproducibility of Results; Sensitivity and Specificity
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Sources: Web Of Science, NC State University Libraries
Added: August 6, 2018

2007 journal article

Stochastic and deterministic models for agricultural production networks

Mathematical Biosciences and Engineering, 4(3), 373–402.

By: P. Bai*, H. Banks*, S. Dediu*, A. Govan, M. Last, A. Lloyd*, H. Nguyen*, M. Olufsen*, G. Rempala, B. Slenning*

Contributors: P. Bai*, H. Banks*, S. Dediu*, A. Govan, M. Last, A. Lloyd*, H. Nguyen*, M. Olufsen*, G. Rempala, B. Slenning*

MeSH headings : Animal Husbandry / methods; Animal Husbandry / organization & administration; Animals; Animals, Domestic; Computer Simulation; Models, Biological; Models, Organizational; Models, Statistical; Stochastic Processes; Swine / growth & development
TL;DR: An approach to modeling the impact of disturbances in an agricultural production network and its approximate deterministic model for averages over sample paths of the stochastic system are presented. (via Semantic Scholar)
UN Sustainable Development Goal Categories
2. Zero Hunger (OpenAlex)
Sources: NC State University Libraries, ORCID, NC State University Libraries
Added: August 6, 2018

2007 journal article

The Disparate Effects of Microvascular Rarefaction and Reduced Compliance on Proximal Haemodynamics: Investigation with a Mathematical and Computational Model of the Circulation

Artery Research, 1(2), 74.

By: G. Vaughan*, M. Johnson*, P. Mark, J. Connell, M. Olufsen n, N. Hill*, C. Sainsbury

UN Sustainable Development Goal Categories
2. Zero Hunger (OpenAlex)
Source: Crossref
Added: January 5, 2021

2006 journal article

Analysis of blood flow velocity and pressure signals using the multipulse method

Mathematical Biosciences and Engineering, 3(2), 419–440.

By: D. Justice, H. Trussell & M. Olufsen n

TL;DR: This paper shows how the multipulse method from digital signal processing can be used to accurately synthesize signals obtained from blood pressure and blood flow velocity sensors during posture change from sitting to standing. (via Semantic Scholar)
Source: NC State University Libraries
Added: August 6, 2018

2006 chapter

Cardiovascular modeling at IMFUFA, in The way through science and philosophy

In H. B. Andersen, F. V. Christiansen, K. F. Jorgensen, & V. F. Hendricks (Eds.), Tributes (Vol. 4, pp. 87–96). London: College Publications.

By: J. Larsen, V. Andreasen, H. Larsen, M. Olufsen & J. Ottesen

Ed(s): H. Andersen, F. Christiansen, K. Jorgensen & V. Hendricks

Source: NC State University Libraries
Added: July 10, 2019

2006 journal article

Modeling baroreflex regulation of heart rate during orthostatic stress

AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 291(5), R1355–R1368.

By: M. Olufsen n, H. Tran*, J. Ottesen, L. Lipsitz & V. Novak

author keywords: mathematical modeling; heart rate control; baroreflex function; sympathetic and parasympathetic responses; vestibulo-sympathetic reflex
MeSH headings : Adult; Aged; Aged, 80 and over; Baroreflex / physiology; Blood Pressure / physiology; Dizziness / physiopathology; Female; Fingers / blood supply; Heart Rate / physiology; Humans; Hypertension / physiopathology; Male; Middle Aged; Models, Theoretical
TL;DR: A mathematical model that can predict the dynamics of heart rate regulation in response to postural change from sitting to standing is presented and it is demonstrated that this model can accurately predict heart rate dynamics observed in data obtained from healthy young, healthy elderly, and hypertensive elderly subjects. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Sources: Web Of Science, NC State University Libraries
Added: August 6, 2018

2005 journal article

Blood pressure and blood flow variation during postural change from sitting to standing: model development and validation

JOURNAL OF APPLIED PHYSIOLOGY, 99(4), 1523–1537.

By: M. Olufsen n, J. Ottesen, H. Tran*, L. Ellwein*, L. Lipsitz & V. Novak

author keywords: cardiovascular system; mathematical modeling; cerebral blood flow; gravitational effect; autonomic regulation; cerebral autoregulation
MeSH headings : Autonomic Nervous System / physiology; Blood Circulation / physiology; Blood Pressure / physiology; Cerebrovascular Circulation / physiology; Homeostasis; Humans; Linear Models; Models, Cardiovascular; Posture / physiology
TL;DR: A mathematical model is presented that can predict dynamic changes in beat-to-beat arterial blood pressure and middle cerebral artery blood flow velocity during postural change from sitting to standing and is in agreement with physiological data from a young subject during postures change from Sitting to standing. (via Semantic Scholar)
Sources: Web Of Science, NC State University Libraries
Added: August 6, 2018

2004 book

Applied Mathematical Models in Human Physiology

By: J. Ottesen, M. Olufsen* & J. Larsen

TL;DR: This work has shown that the ejection effect of the pumping heart affects flow and pressure in the systemic arteries and the baroreceptor model is a good fit for this purpose. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (OpenAlex)
Source: Crossref
Added: July 20, 2019

2004 journal article

Modeling Cerebral Blood Flow Control During Posture Change from Sitting to Standing

Cardiovascular Engineering, 4(1), 47–58.

By: M. Olufsen n, H. Tran n & J. Ottesen

TL;DR: A mathematical model is presented that can predict blood flow and pressure during posture change from sitting to standing and uses a compartmental approach to describe pulsatile blood flow velocity and pressure in a number of compartments representing the systemic circulation. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (OpenAlex)
Sources: Crossref, NC State University Libraries
Added: July 20, 2019

2004 journal article

On deriving lumped models for blood flow and pressure in the systemic arteries

MATHEMATICAL BIOSCIENCES AND ENGINEERING, 1(1), 61–80.

By: M. Olufsen n & A. Nadim n

author keywords: arterial modeling; lumped arterial models
TL;DR: This paper starts with the onedimensional axisymmetric Navier-Stokes equations for time-dependent blood flow in a rigid vessel to derive lumped models relating flow and pressure and focuses on zeroth, first and second order models and relate them to electrical circuit analogs, in which current is equivalent to flow and voltage to pressure. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2003 journal article

New roles for the gamma rhythm: Population tuning and preprocessing for the beta rhythm

JOURNAL OF COMPUTATIONAL NEUROSCIENCE, 14(1), 33–54.

By: M. Olufsen n, M. Whittington*, M. Camperi* & N. Kopell*

author keywords: gamma rhythms; beta rhythms; cell assembly formation; plasticity; hippocampus; neocortex; preprocessing
MeSH headings : Animals; Beta Rhythm; Computer Simulation; Electric Stimulation; Electroencephalography; Excitatory Postsynaptic Potentials; Hippocampus / cytology; Hippocampus / physiology; In Vitro Techniques; Interneurons / physiology; Male; Models, Neurological; Neural Inhibition; Neural Networks, Computer; Neuronal Plasticity / physiology; Noise; Oscillometry; Periodicity; Pyramidal Cells / physiology; Rats; Rats, Sprague-Dawley; Reaction Time / physiology; Time Factors
TL;DR: It is shown that gamma and beta rhythms have different properties with respect to creation of cell assemblies, and experimental evidence showing that such a separation can occur in hippocampal slices is presented. (via Semantic Scholar)
Source: Web Of Science
Added: August 6, 2018

2002 journal article

Dynamics of cerebral blood flow regulation explained using a lumped parameter model

AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, 282(2), R611–R622.

By: M. Olufsen n, A. Nadim* & L. Lipsitz*

author keywords: cerebral autoregulation; arterial modeling
MeSH headings : Blood Pressure / physiology; Cerebral Arteries / physiology; Cerebrovascular Circulation / physiology; Homeostasis / physiology; Humans; Models, Cardiovascular
TL;DR: A windkessel model with two resistors and a capacitor to reproduce beat-to-beat changes in middle cerebral artery blood flow velocity in response to arterial pressure changes measured in the finger suggests that the initial increase in cerebrovascular resistance can explain the widening of the cerebral blood flow pulse observed in young subjects. (via Semantic Scholar)
UN Sustainable Development Goal Categories
3. Good Health and Well-being (Web of Science; OpenAlex)
Source: Web Of Science
Added: August 6, 2018

2001 chapter

A One-Dimensional Fluid Dynamic Model of the Systemic Arteries

In Computational Modeling in Biological Fluid Dynamics (pp. 167–187).

By: M. Olufsen*

TL;DR: A structured tree in which the root impedance is calculated using a semi-analytical approach provides a dynamical boundary condition based on physiological principles which is computationally feasible. (via Semantic Scholar)
Source: Crossref
Added: July 20, 2019

2001 journal article

A lumped parameter model for cerebral blood flow regulation

Advances in Bioengineering, 51, 277–278.

By: M. Olufsen, L. Lipsitz & A. Nadim

Source: NC State University Libraries
Added: July 28, 2019

2000 chapter

A one-dimensional fluid dynamic model of the systemic arteries

In J. T. Ottesen & M. Danielsen (Eds.), Mathematical modelling in medicine (pp. 79–97).

By: M. Olufsen

Ed(s): J. Ottesen & M. Danielsen

Source: NC State University Libraries
Added: August 18, 2019

2000 journal article

Numerical Simulation and Experimental Validation of Blood Flow in Arteries with Structured-Tree Outflow Conditions

Annals of Biomedical Engineering, 28(11), 1281–1299.

By: M. Olufsen*, C. Peskin*, W. Kim*, E. Pedersen*, A. Nadim* & J. Larsen

author keywords: arterial blood flow; arterial modeling; blood flow modeling; arterial outflow conditions; biofluid dynamics; mathematical modeling
MeSH headings : Adult; Algorithms; Aorta / physiology; Arteries / physiology; Biomedical Engineering; Blood Pressure / physiology; Hemodynamics / physiology; Hemorheology; Humans; Magnetic Resonance Angiography; Male; Models, Cardiovascular; Regional Blood Flow / physiology
TL;DR: Comparison between the simulations and magnetic resonance measurements in the ascending aorta and nine peripheral locations in one individual shows excellent agreement between the two. (via Semantic Scholar)
Source: Crossref
Added: July 20, 2019

1999 journal article

Structured tree outflow condition for blood flow in larger systemic arteries

American Journal of Physiology-Heart and Circulatory Physiology, 276(1), H257–H268.

By: M. Olufsen*

author keywords: arterial modeling; mathematical modeling; arterial outflow boundary condition
MeSH headings : Arteries / physiology; Blood Pressure / physiology; Humans; Models, Cardiovascular; Pulsatile Flow; Regional Blood Flow / physiology; Vascular Resistance / physiology
TL;DR: A structured tree attached to the terminal branches of the truncated arterial tree in which the root impedance is estimated using a semianalytical approach based on a linearization of the viscous axisymmetric Navier-Stokes equations provides a dynamic boundary condition that maintains the phase lag between blood flow and pressure as well as the high-frequency oscillations present in the impedance spectra. (via Semantic Scholar)
Source: Crossref
Added: July 27, 2019

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