We measure the absolute dispersion of clouds of monodisperse, phosphorescent droplets in turbulent air by means of high-speed image-intensified video recordings. Laser excitation allows the initial preparation of well-defined, pencil-shaped luminous droplet clouds in a completely nonintrusive way. We find that the dispersion of the clouds is faster than the dispersion of fluid elements. We speculate that preferential concentration of inertial droplet clouds is responsible for the enhanced dispersion.
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http://dx.doi.org/10.1103/PhysRevLett.117.164501 | DOI Listing |
J Ultrasound Med
January 2025
Department of Ultrasound, The Second Affiliated Hospital of Army Medical University, Chongqing, China.
Objectives: Our previous studies have found that low-frequency, low-pressure, weakly focused ultrasound (FUS) can induce acoustic droplet vaporization (ADV) of perfluoropentane (PFP) droplets and result in localized liver and prostate tissue controllable cavitation resonance and mechanical damage. To further investigate the mechanical erosion induced by ultrasound and locally injected phase-shift acoustic droplets in rabbit liver.
Methods: The liver of each rabbit was treated with perfluoromethylcyclopentane (PFMCP) alone, FUS combined with PFMCP (FUS + PFMCP), and FUS combined with PFP (FUS + PFP).
Anal Chim Acta
February 2025
Institute of Environmental Science, Shanxi University, Taiyuan 030006, China.
Hypochlorous acid (HClO) is a well-known inflammatory signaling molecule, while lipid droplets (LDs) are dynamic organelles closely related to inflammation. Using organic small-molecule fluorescence imaging technology to target LDs for precise monitoring of HClO is one of the most effective methods for diagnosing inflammation-related diseases. A thorough investigation of how probes detect biological markers and the influencing factors can aid in the design of probe molecules, the selection of high-performance tools, and the accuracy of disease detection.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Department of Chemistry, University of Helsinki, FI-00014 Helsinki, Finland.
Quantum chemical calculations were employed to construct Jablonski diagrams for a series of phenolic carbonyls, including vanillin, iso-vanillin, 4-hydroxybenzaldehyde, syringaldehyde, and coniferyl aldehyde. These molecules can enter the Earth's atmosphere from forest fire emissions and participate in photochemical reactions within the atmospheric condensed phase, including cloud and fog droplets and aqueous aerosol particles. This photochemistry alters the composition of light-absorbing organic content, or brown carbon, in droplets and particles through the formation and destruction of key chromophores.
View Article and Find Full Text PDFNature
December 2024
Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland.
Aircraft observations have revealed ubiquitous new particle formation in the tropical upper troposphere over the Amazon and the Atlantic and Pacific oceans. Although the vapours involved remain unknown, recent satellite observations have revealed surprisingly high night-time isoprene mixing ratios of up to 1 part per billion by volume (ppbv) in the tropical upper troposphere. Here, in experiments performed with the CERN CLOUD (Cosmics Leaving Outdoor Droplets) chamber, we report new particle formation initiated by the reaction of hydroxyl radicals with isoprene at upper-tropospheric temperatures of -30 °C and -50 °C.
View Article and Find Full Text PDFNat Commun
November 2024
Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA.
Wildfires emit solid-state strongly absorptive brown carbon (solid S-BrC, commonly known as tar ball), critical to Earth's radiation budget and climate, but their highly variable light absorption properties are typically not accounted for in climate models. Here, we show that from a Pacific Northwest wildfire, over 90% of particles are solid S-BrC with a mean refractive index of 1.49 + 0.
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