58 research outputs found
Further development of an algorithm for the nonlinear stability analysis of the orbiting astronomical observatory paired-tracker control system Final report
Algorithm development for estimating domain of attraction of OAO paired-tracker equilibrium state with Liapunov function
Optical and acoustical dynamics of microbubble contrast agents inside neutrophils.
Acoustically active microbubbles are used for contrast-enhanced ultrasound assessment of organ perfusion. In regions of inflammation, contrast agents are captured and phagocytosed by activated neutrophils adherent to the venular wall. Using direct optical observation with a high-speed camera and acoustical interrogation of individual bubbles and cells, we assessed the physical and acoustical responses of both phagocytosed and free microbubbles. Optical analysis of bubble radial oscillations during insonation demonstrated that phagocytosed microbubbles experience viscous damping within the cytoplasm and yet remain acoustically active and capable of large volumetric oscillations during an acoustic pulse. Fitting a modified version of the Rayleigh-Plesset equation that describes mechanical properties of thin shells to optical radius-time data of oscillating bubbles provided estimates of the apparent viscosity of the intracellular medium. Phagocytosed microbubbles experienced a viscous damping approximately sevenfold greater than free microbubbles. Acoustical comparison between free and phagocytosed microbubbles indicated that phagocytosed microbubbles produce an echo with a higher mean frequency than free microbubbles in response to a rarefaction-first single-cycle pulse. Moreover, this frequency increase is predicted using the modified Rayleigh-Plesset equation. We conclude that contrast-enhanced ultrasound can detect distinct acoustic signals from microbubbles inside of neutrophils and may provide a unique tool to identify activated neutrophils at sites of inflammation
Nicosulfuron and Primisulfuron Root Uptake, Translocation, and Inhibition of Acetolactate Synthase in Sugarbeet ( Beta vulgaris
Quantitative Volumetric Perfusion Mapping of the Microvasculature Using Contrast Ultrasound
Magnetically-actuated micromechanical nickel patches for a monolithically integrated reconfigurable antenna on printed circuit board
Optimization of ultrasound parameters for cardiac gene delivery of adenoviral or plasmid deoxyribonucleic acid by Ultrasound-Targeted microbubble destruction
Localized ultrasound enhances delivery of rapamycin from microbubbles to prevent smooth muscle proliferation
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