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Acoustic wave propagation in ultrasonic flow measurements is typically assumed to be linear and reciprocal. However, if the transmitting transducer generates a sufficiently high pressure, nonlinear wave propagation effects become significant. In flow measurements, this would translate into more information to estimate the flow and therefore a higher precision relative to the linear case. In this work, we investigate how the generated harmonics can be used to measure flow. Measurements in a custom-made flow loop and simulations using the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation will show that the second harmonic component provides similar transit time differences to those obtained from the fundamental component, their linear combination results in more precise flow measurements compared to the estimations with the fundamental component alone.
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http://dx.doi.org/10.1016/j.ultras.2021.106476 | DOI Listing |
JAMA Cardiol
September 2025
Department of Cardiology, Inselspital University Hospital of Bern, University of Bern, Bern, Switzerland.
Importance: Right anomalous aortic origin of a coronary artery (R-AAOCA) is a rare congenital condition increasingly diagnosed with the growing use of cardiac imaging. Due to dynamic compression of the anomalous vessel, invasive fractional flow reserve (FFR) during a dobutamine-atropine volume challenge (FFR-dobutamine) is considered the reference standard. A reliable alternative method is needed to reduce extensive invasive testing, but it remains uncertain whether noninvasive imaging can accurately assess the hemodynamic relevance of R-AAOCA.
View Article and Find Full Text PDFActa Neurochir (Wien)
September 2025
Department of Neurosurgery, Medical University of Gdańsk, Gdańsk, Poland.
Purpose: Moyamoya disease (MMD) is a chronic cerebrovascular disorder characterized by progressive arterial stenosis and fragile collateral formation, elevating stroke risk. Revascularization is the standard treatment, yet up to 27% of patients experience ischemic events within a year due to bypass insufficiency. While digital subtraction angiography (DSA) remains the gold standard for assessing bypass function, it is invasive and time-consuming.
View Article and Find Full Text PDFFASEB J
September 2025
Department of Plastic Surgery and Burn, Third XiangYa Hospital, Central South University, Changsha, Hunan, China.
Defective wounds pose health risks, and treatment is challenging. Umbilical cord-derived mesenchymal stem cells (UCMSCs) show promise for healing. Primary UCMSCs were isolated and extracted in vitro, and the proliferation and differentiation characteristics were detected by flow cytometry and trilineage differentiation, and a 3D spherical cell culture was performed.
View Article and Find Full Text PDFInvest Ophthalmol Vis Sci
September 2025
Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, United States.
Purpose: To assess macular choriocapillaris (CC) metrics in healthy volunteers (HVs) without ocular disease and demonstrate CC variations in patients with inherited retinal dystrophies (IRDs) using adaptive optics optical coherence tomography angiography (AO-OCTA).
Methods: Twenty-one HVs and three IRD patients were imaged. Macular variation in 20 HVs in CC metrics (CC density, CC diameter, CC tortuosity, void diameter, void area, lobule count, lobule area, and RPE-CC distance) were assessed by imaging a 28° strip of overlapping AO-OCTA volumes (3° × 3°) from the optic nerve head to the temporal macula.
Pediatr Infect Dis J
September 2025
From the Pediatric Infectious Diseases Unit, Gregorio Marañón University Hospital, Madrid, Spain.
Background: Vaccination is a key strategy to reduce infectious disease mortality. In pediatric heart transplant recipients (HTRs), the use of immunosuppressive therapy weakens immune responses, increasing the risk of viral infections. This study aimed to evaluate the immunogenicity of hepatitis B virus (HBV) revaccination in this vulnerable population.
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