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Full-Text Articles in Physics

Evolution Of Spur-Length Diversity In Aquilegia Petals Is Achieved Solely Through Cell-Shape Anisotropy, Joshua R. Puzey, Sharon J. Gerbode, Scott A. Hodges, Elena M. Kramer, L. Mahadevan Nov 2011

Evolution Of Spur-Length Diversity In Aquilegia Petals Is Achieved Solely Through Cell-Shape Anisotropy, Joshua R. Puzey, Sharon J. Gerbode, Scott A. Hodges, Elena M. Kramer, L. Mahadevan

All HMC Faculty Publications and Research

The role of petal spurs and specialized pollinator interactions has been studied since Darwin. Aquilegia petal spurs exhibit striking size and shape diversity, correlated with specialized pollinators ranging from bees to hawkmoths in a textbook example of adaptive radiation. Despite the evolutionary significance of spur length, remarkably little is known about Aquilegia spur morphogenesis and its evolution. Using experimental measurements, both at tissue and cellular levels, combined with numerical modelling, we have investigated the relative roles of cell divisions and cell shape in determining the morphology of the Aquilegia petal spur. Contrary to decades-old hypotheses implicating a discrete meristematic zone …


Effect Of Substrate Composition And Alignment On Corneal Cell Phenotype, Donna Phu '09, Lindsay S. Wray '08, Robert V. Warren '10, Richard C. Haskell, Elizabeth J. Orwin Jan 2011

Effect Of Substrate Composition And Alignment On Corneal Cell Phenotype, Donna Phu '09, Lindsay S. Wray '08, Robert V. Warren '10, Richard C. Haskell, Elizabeth J. Orwin

All HMC Faculty Publications and Research

Corneal blindness is a significant problem treated primarily by corneal transplants. Donor tissue supply is low, creating a growing need for an alternative. A tissue-engineered cornea made from patient-derived cells and biopolymer scaffold materials would be widely accessible to all patients and would alleviate the need for donor sources. Previous work in this lab led to a method for electrospinning type I collagen scaffolds for culturing corneal fibroblasts ex vivo that mimics the microenvironment in the native cornea. This electrospun scaffold is composed of small-diameter, aligned collagen fibers. In this study, we investigate the effect of scaffold nanostructure and composition …


Evidence Of The Harmonic Faraday Instability In Ultrasonic Atomization Experiments With A Deep, Inviscid Fluid, Andrew P. Higginbotham '09, Aaron Guillen '11, Nathan C. Jones '10, Thomas D. Donnelly, Andrew J. Bernoff Jan 2011

Evidence Of The Harmonic Faraday Instability In Ultrasonic Atomization Experiments With A Deep, Inviscid Fluid, Andrew P. Higginbotham '09, Aaron Guillen '11, Nathan C. Jones '10, Thomas D. Donnelly, Andrew J. Bernoff

All HMC Faculty Publications and Research

A popular method for generating micron-sized aerosols is to submerge ultrasonic (ω~MHz) piezoelectric oscillators in a water bath. The submerged oscillator atomizes the fluid, creating droplets with radii proportional to the wavelength of the standing wave at the fluid surface. Classical theory for the Faraday instability predicts a parametric instability driving a capillary wave at the subharmonic (ω/2) frequency. For many applications it is desirable to reduce the size of the droplets; however, using higher frequency oscillators becomes impractical beyond a few MHz. Observations are presented that demonstrate that smaller droplets may also be created by …