Immunohistochemical characterization of the rabbit tracheal cartilages

This is the published version. Copyright © 2010 SciRes.The objective of this study was to immunohistochemically elucidate the major extracellular matrix constituents of rabbit tracheal cartilage. The impetus for this project is the need for crucial design and validation criteria for tissue engineering juxtaposed with the conspicuous lack of trachea extracellular matrix data in the literature. Tracheal tissue specimens were harvested from New Zealand White rabbits, and were immunostained for collagen I, collagen II, aggrecan and decorin; and a Verhoeff-Van Gieson stain was performed to visualize elastin. The most striking result was the highly organized relationship between distinct fibrous (containing collagen I, decorin and elastin) and hyaline-like (containing collagen II and aggrecan) regions of the tracheal wall. The tracheal cartilage stained strongly with collagen II throughout, with periodic bands of aggrecan in the tracheal arches, meaning that there were areas void of aggrecan immunostaining alternating with areas with strong aggrecan immunostaining. In contrast, the periphery of the cartilage and the perichondrium itself exhibited strong collagen I staining and no collagen II staining. Elastin fibers and decorin were also detected along the periphery of the cartilage in the perichondrium and corresponded highly with the distribution of collagen I staining. The body of the rabbit trachea is therefore composed of a hyaline-cartilage structure primarily made of collagen II and bands of aggrecan, surrounded by a fibrous region composed of elastin and collagen I, indicative of a flexible tissue with distinct regions of compressive integrity. This information will be a valuable reference to future tissue engineering efforts in the creation of a biosynthetic substitute for laryngotracheal reconstruction

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Lattice parameter accommodation between GaAs(111) nanowires and Si(111) substrate after growth via Au-assisted molecular beam epitaxy

Using out-of-plane and in-plane X-ray diffraction techniques, we have investigated the structure at the interface between GaAs nanowires [NWs] grown by Au-assisted molecular beam epitaxy and the underlying Si(111) substrate. Comparing the diffraction pattern measured at samples grown for 5, 60, and 1,800 s, we find a plastic strain release of about 75% close to the NW-to-substrate interface even at the initial state of growth, probably caused by the formation of a dislocation network at the Si-to-GaAs interface. In detail, we deduce that during the initial stage, zinc-blende structure GaAs islands grow with a gradually increasing lattice parameter over a transition region of several 10 nm in the growth direction. In contrast, accommodation of the in-plane lattice parameter takes place within a thickness of about 10 nm. As a consequence, the ratio between out-of-plane and in-plane lattice parameters is smaller than the unity in the initial state of growth. Finally the wurtzite-type NWs grow on top of the islands and are free of strain