The recent development of x-ray free electron lasers providing coherent, femtosecond-long pulses of high brilliance and variable energy opens new areas of scientific research in a variety of disciplines such as physics, chemistry, and biology. Pump-probe experimental techniques which observe the temporal evolution of systems after optical or x-ray pulse excitation are one of the main experimental schemes currently in use for ultrafast studies. The key challenge in these experiments is to reliably achieve temporal and spatial overlap of the x-ray and optical pulses. Here we present measurements of the x-ray pulse induced transient change of optical reflectivity from a variety of materials covering the soft x-ray photon energy range from 500eV to 2000eV and outline the use of this technique to establish and characterize temporal synchronization of the optical-laser and FEL x-ray pulses.
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http://dx.doi.org/10.1364/OE.20.011396 | DOI Listing |
J Ultrasound Med
January 2025
Department of Emergency Medicine, The University of Arizona College of Medicine, Tucson, Arizona, USA.
Objectives: The prognostic characteristics of lung point-of-care ultrasound (L-POCUS) to predict respiratory decompensation in patients with emerging infections remains unstudied. Our objective was to examine whether scored lung ultrasounds predict hypoxia among a nonhypoxic, ambulatory population of patients with COVID-19.
Methods: This was a diagnostic case-control study.
BMC Cardiovasc Disord
January 2025
Department of Cardiology, The Affiliated Hospital of Xuzhou Medical University, 99#, Huaihai West Road, Xuzhou, 221002, China.
Background: Previous studies have shown that epicardial edipose tissue(EAT) appears to be associated with myocardial inflammation and fibrosis, but this is not clear in patients with new-onset atrial arrhythmias after STEMI. The present study focused on using CMR to assess the association of epicardial fat with myocardial inflammation and fibrosis and its predictive value in patients with new-onset atrial arrhythmias after STEMI.
Methods: This was a single-centre, retrospective study.
Nat Commun
January 2025
SLAC National Accelerator Laboratory, Stanford PULSE Institute, Menlo Park, CA, USA.
Diffraction-before-destruction imaging with ultrashort X-ray pulses can visualize non-equilibrium processes, such as chemical reactions, with sub-femtosecond precision in the native environment. Here, a nanospecimen diffracts a single X-ray flash before it disintegrates. The sample structure can be reconstructed from the coherent diffraction image (CDI).
View Article and Find Full Text PDFEchocardiography
January 2025
Cardiology Department, Soroka University Medical Center, Beer-Sheba, Israel.
Background: Timing of treatment of aortic stenosis (AS) is of key importance. AS severity is currently determined by transthoracic echocardiography (TTE) with a main focus on mean trans-aortic gradients. However, echocardiography has its limitations.
View Article and Find Full Text PDFJ Thorac Dis
December 2024
Department of Diagnostic Radiology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Chest computed tomography (CT) is the most frequently performed imaging examination worldwide. Compared with chest radiography, chest CT greatly improves the detection rate and diagnostic accuracy of chest lesions because of the absence of overlapping structures and is the best imaging technique for the observation of chest lesions. However, there are still frequently missed diagnoses during the interpretation process, especially in certain areas or "blind spots", which may possibly be overlooked by radiologists.
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