Publications by authors named "Stephen Dicker"

Article Synopsis
  • The study investigates how changes in the composition of microbubble shells, specifically the amount and weight of polyethylene glycol (PEG), affect their resonance frequency when ultrasound waves pass through them.
  • The experiments show that at low PEG concentrations (0.01), the molecular weight has little effect on resonance frequency; however, at higher concentrations (0.075), the resonance frequency decreases significantly with increasing PEG molecular weight.
  • Data analysis using the Sarkar bubble dynamics model reveals a consistent pattern with theoretical predictions regarding the elastic modulus, confirming its constancy in the mushroom regime and a decrease in the brush regime as molecular weight increases.
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The effect of modifying the shell composition of a population of microbubbles on their size demonstrated through experiment. Specifically, these variations include altering both the mole fraction and molecular weight of functionalized polymer, polyethylene glycol (PEG) in the microbubble phospholipid monolayer shell (1-15 mol% PEG, and 1000-5000 g/mole, respectively). The size distribution is measured with an unbiased image segmentation program written in MATLAB which identifies and sizes bubbles from micrographs.

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This paper discusses various interactions between ultrasound, phospholipid monolayer-coated gas bubbles, phospholipid bilayer vesicles, and cells. The paper begins with a review of microbubble physics models, developed to describe microbubble dynamic behavior in the presence of ultrasound, and follows this with a discussion of how such models can be used to predict inertial cavitation profiles. Predicted sensitivities of inertial cavitation to changes in the values of membrane properties, including surface tension, surface dilatational viscosity, and area expansion modulus, indicate that area expansion modulus exerts the greatest relative influence on inertial cavitation.

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