Microwave reflectometry might be a suitable tool for the thoracic surgeon to monitor edema formation of the lung during lung surgery. A new setup of microwave reflectometry for lung water measurements was developed and tested for clinical application. Three lung models were used for the microwave reflectometry tests: 1) the model of an ex vivo isolated perfused rat lung to investigate lung edema formation during ischemia-reperfusion (n=6), 2) the in situ lung of a human patient to demonstrate the feasibility of lung water monitoring during a surgical operation, 3) the model of an ex vivo isolated perfused human lung to investigate edema formation during postischemic reperfusion and to investigate the changes in water content in the region of a tumor. During human lung operation, significant changes in water content occurred in different lung areas. During isolated perfusion, a significant increase in lung water was measured in models 1) and 3) (P=0.03). Water content of tumor tissue was higher than in the surrounding healthy lung tissue. Microwave reflectometry offers a non-invasive approach to monitor lung edema formation in experimental models and during thoracic surgery.
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http://dx.doi.org/10.1510/icvts.2010.243691 | DOI Listing |
Sci Rep
October 2024
Faculty of Environment, University of Tehran, Tehran, Iran.
Soil moisture (SM) is a critical variable influencing various environmental processes, but traditional microwave sensors often lack the spatial resolution needed for local-scale studies. This study develops a novel stacking ensemble learning framework to enhance the spatial resolution of satellite-derived SM data to 1 km in the Urmia basin, a region facing significant water scarcity. We integrated in-situ SM measurements (obtained using time-domain reflectometry [TDR]), Soil Moisture Active Passive (SMAP) and Advanced Microwave Scanning Radiometer 2 (AMSR2) SM products, Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature and vegetation indices, precipitation records, and topography data.
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August 2024
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA.
Spaceborne radar remote sensing of the earth system is essential to study natural and man-made changes in the ecosystem, water and energy cycles, weather and air quality, sea level, and surface dynamics. A major challenge with current approaches is the lack of broad spectrum tunability due to narrow band microwave electronics, that limit systems to specific science variable retrievals. This results in a significant limitation in studying dynamic coupled earth system processes such as surface and subsurface hydrology from a single compact instrument, where co-located broad spectrum radar remote sensing is needed to sense multiple variables simultaneously or over a short duration.
View Article and Find Full Text PDFRev Sci Instrum
July 2024
University of California Davis, Davis, California 95616, USA.
Microwave reflectometry is an invaluable diagnostic tool for measuring electron density profiles in large fusion devices. Density fluctuations near the plasma cutoff layer, particularly those that are time-varying on the timescale of the reflectometry measurement, can result in distortions in phase and/or amplitude of the reflected waveform, which present challenges to the accuracy of the reconstructed profile. The ultra-short pulse reflectometry (USPR) technique eliminates the time-varying issue in that reflectometry data are collected on a nanosecond timescale, essentially freezing the fluctuations in place.
View Article and Find Full Text PDFNano Lett
July 2024
CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences, University of Science and Technology of China, Hefei 230026, China.
Cryogenic temperatures are crucial for the operation of semiconductor quantum electronic devices, yet the heating effects induced by microwave or laser signals used for quantum state manipulation can lead to significant temperature variations at the nanoscale. Therefore, probing the temperature of individual devices in working conditions and understanding the thermodynamics are paramount for designing and operating large-scale quantum computing systems. In this study, we demonstrate high-sensitivity fast thermometry in a silicon nanotransistor at cryogenic temperatures using RF reflectometry.
View Article and Find Full Text PDFSensors (Basel)
May 2024
Department of Engineering for Innovation, University of Salento, 73100 Lecce, Italy.
This study investigates the dielectric properties of conductive biocomposites (CBs), which are integral to the development of advanced materials for flexible electronics and medical devices. A novel method employing Microwave Reflectometry (MR) is introduced, utilizing a miniaturized Vector Network Analyzer (m-VNA) and a dedicated sensing element (SE), to extract the dielectric properties of CBs. The method is grounded in a minimization principle, aligning the measured S11 reflection scattering parameter with its electromagnetic (EM) simulation, facilitating a refined process for determining the dielectric properties.
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