A5051366404- Fluid Dynamics and Turbulent Flows
- Cardiovascular Function and Risk Factors
- Combustion and flame dynamics
- Pulmonary Hypertension Research and Treatments
- Aerodynamics and Acoustics in Jet Flows
- Plasma and Flow Control in Aerodynamics
- Ultrasound and Hyperthermia Applications
- Cardiovascular Health and Disease Prevention
- Infection Control and Ventilation
- Cardiac Valve Diseases and Treatments
- Flow Measurement and Analysis
- Congenital Heart Disease Studies
- Experimental and Theoretical Physics Studies
- Wind and Air Flow Studies
- Cardiac Imaging and Diagnostics
- Aesthetic Perception and Analysis
- Ultrasound Imaging and Elastography
- Advanced MRI Techniques and Applications
- Meteorological Phenomena and Simulations
- Advanced Sensor and Energy Harvesting Materials
- Particle Dynamics in Fluid Flows
- Coronary Interventions and Diagnostics
- Acoustic Wave Resonator Technologies
- Photoacoustic and Ultrasonic Imaging
- Engineering Education and Pedagogy
University of Colorado System
1996-2024
University of Colorado Boulder
2013-2024
University of Colorado Denver
2001-2024
Atlas Scientific (United States)
2018-2020
University of California, Berkeley
1984-2020
National Jewish Health
2013
University of Colorado Health
2001-2004
Children's Hospital Colorado
2001
Lawrence Berkeley National Laboratory
1988
Cough generated infectious aerosols are of interest while developing strategies for the mitigation disease risks ranging from common cold to SARS. In this work, velocity field human cough was measured using particle image velocimetry (PIV). The project subjects (total 29) coughed into an enclosure seeded with stage fog. flow profiles, average widths jet, and maximum velocities were measured. Maximum ranged 1.5 m/s 28.8 m/s. width all coughs between 35 45 mm. Wide variability in data suggests...
Background —Early recognition of heart disease is an important goal in pediatrics. Efforts developing inexpensive screening device that can assist the differentiation between innocent and pathological murmurs have met with limited success. Artificial neural networks (ANNs) are valuable tools used complex pattern classification tasks. The aim present study was to train ANN distinguish effectively. Methods Results —Using electronic stethoscope, sounds were recorded from 69 patients (37 32...
Pulmonary hypertension (PH) is associated with proximal pulmonary arterial remodeling characterized by increased vessel diameter, wall thickening, and stiffness. In vivo assessment of shear stress (WSS) may provide insights into the relationships between hemodynamics vascular remodeling. We investigated relationship main artery (MPA) WSS as well markers As part a prospective study, 17 PH patients 5 controls underwent same-day four-dimensional flow cardiac magnetic resonance imaging (4-D CMR)...
Right ventricular diastolic dysfunction (RVDD) is an important prognostic indicator in pulmonary arterial hypertension (PAH). RV vortex rings have been observed healthy subjects, but their significance RVDD unknown. Vorticity, the local spinning motion of element fluid, may be a sensitive measure dynamics. Using four-dimensional (4D) flow cardiac magnetic resonance imaging (CMR), we investigated relationship between right heart vorticity with echocardiographic indexes RVDD. Thirteen (13) PAH...
Outbreaks from choir performances, such as the Skagit Valley Choir, showed that singing brings potential risk of COVID-19 infection. There is less known about risks airborne infection other musical playing wind instruments or performing theater. In addition, it important to understand methods can be used reduce risk. this study, we a variety methods, including flow visualization, aerosol and CO2 measurements, computational fluid dynamics (CFD) modeling different components lead transmission...
This letter reports on a contrast-based ultrasonic particle imaging technique (echo PIV) for measuring multicomponent velocity vectors in opaque flows with excellent temporal (up to 0.5ms) and spatial 0.4mm) resolution. Ultrasound contrast microbubbles are used as flow tracers, digitally acquired rf data converted into B-mode images PIV analysis. Here, fields from various patterns (including rotating transient vortex flows) that difficult measure using other methods such ultrasound Doppler...
We have recently developed an ultrasound-based velocimetry technique, termed echo particle image (Echo PIV), to measure multi-component velocity vectors and local shear rates in arteries opaque fluid flows by identifying tracking flow tracers (ultrasound contrast microbubbles) within these fields. The original system was implemented on images obtained from a commercial echocardiography scanner. Although promising, this limited spatial resolution measurable range. In work, we propose standard...
Stiffening of large arteries is increasingly used as an independent predictor risk and therapeutic outcome for small artery dysfunction in many diseases including pulmonary hypertension. The molecular mechanisms mediating downstream vascular cell responses to stiffening remain unclear. We hypothesize that high pulsatility flow, induced by stiffening, causes inflammatory endothelial cells (PAECs) through toll-like receptor (TLR) pathways. To recapitulate the effect occurs hypertension,...
Purpose To develop an estimate of pulmonary vascular resistance (PVR) using blood flow measurements from 3D velocity‐encoded phase contract magnetic resonance imaging (here termed 4D MRI). Materials and Methods In all, 17 patients with hypertension (PH) five controls underwent right heart catheterization (RHC), 2D Cine MRI (1.5T) within 24 hours. was used to compute maximum spatial peak systolic vorticity in the main artery (MPA) (RPA), cardiac output, relative area change MPA. These...
Current evaluation of pulmonary hypertension (PH) in children involves measurement vascular resistance (PVR); however, PVR neglects important pulsatile components. Pulmonary artery (PA) input impedance and ventricular power (VP) include mean effects have shown promise as alternative measures function. Here we report the utility pulsed-wave (PW) Doppler-measured instantaneous flow pressure measurements for estimation VP use this method to develop a novel parameter: reactivity compliance.An...
Background — Accurate determination of pulmonary vascular resistance (PVR) is an important component in the evaluation and treatment pediatric patients with hypertension. We developed a novel technique, based on concept flow propagation, to estimate PVR noninvasively. The hypothesis that changes cause velocity propagation (Vel prop ) within main artery Vel can be quantified using color M-mode imaging. Methods Results tested mathematical modeling, vitro experiments, preliminary clinical...
Diastolic dysfunction, a leading cause of heart failure in the US, is complex pathology which manifests morphological and hemodynamic changes circulatory system. Recent advances time-resolved phase-contrast cardiac magnetic resonance imaging (4D Flow) have allowed for characterization blood flow right ventricle (RV) atrium (RA), including calculation vorticity qualitative visual assessment coherent patterns. We hypothesize that ventricular diastolic dysfunction (RVDD) associated with flow....
Abstract An optical study of tbe interaction a laminar, premixed, rod stabilized flame and Karman vortex street has been performed. The technique used was laser tomography, in which the unburned gases are seeded with silicone oil spray then illuminated sheet light. evaporates disappears passing through flame, making possible high speed cinematography structure sheet. wavelength frequency perturbed motion is found to correspond closely that street, allowing simple phenomenological explanation...
Room air distribution in hospital operating rooms (OR) is critical to the effective functioning of surgical procedures, but patterns are governed by complex physics that currently not well understood. Both qualitative and quantitative flow visualization techniques were used evaluate room a full-scale chamber designed simulate room. A laser sheet illumination technique was identify key features distribution, particle image velocimetry (PIV) measure velocity field plane crossing site. Hospital...
Our objective was to determine whether left ventricular (LV) vorticity (ω), the local spinning motion of a fluid element, correlated with markers interdependency in pulmonary hypertension (PH). Maladaptive is associated interventricular septal shift, impaired LV performance, and poor outcomes PH patients, yet pathophysiologic mechanisms underlying fluid-structure interactions are incompletely understood. Because conformational changes chamber geometry affect blood flow formations dynamics, ω...
The exhalation of aerosols during musical performances or rehearsals posed a risk airborne virus transmission in the COVID-19 pandemic. Previous research studied aerosol plumes by only focusing on one factor, either source strength convective transport capability. Furthermore, was characterized concentration and ignored airflow rate needed for analysis actual performances. This study characterizes that account both capability conducting experiments with 18 human subjects. emission rate,...