Fiber wall architecture

Figure 16 shows that the various sublayers or lamellae in the Si, S2, and S3 can exhibit left-handed (parallel to middle bar of an S) and/ or right-handed (parallel to middle bar of a Z) helices. This particular variation in fiber-wall architecture has been investigated in very few wood species, and generalization to include all softwood and hardwood fibers may be a bit risky. However, available data imply that all normal wood fibers may be constructed in principle from a similar blueprint. 

Figure 16, Schematic of what is widely considered to be (at least in principle) the general wall architecture of normal wood fibers. Key ML, middle lamella F, primary wall and Sj, Sg, and So, layers of the secondary wall, (Adapted from Ref, i5.)...

The salient features of tension wood are summarized in Table II. Most notable are the increased volume of fibers, the high cellulose content, low lignin content, and the special wall architecture of tension wood fibers. 

Baxa, U., Taylor, K. L., Wall, J. S., Simon, M. N., Cheng, N., Wickner, R. B., and Steven, A. C. (2003). Architecture of Ure2p prion filaments The N-terminal domains form a central core fiber./. Biol. Chem. 278, 43717-43727. 

Vessel Elements. Architecture. The cell wall of vessel elements appears to be constructed along the same general scheme as wood fibers. However, the layering is generally more complicated, and the presence in many species of numerous intervessel bordered... 

Understanding adhesive-wood cell interactions is more difficult because of the tremendous variability in wood cell types. With tracheid, parenchyma, and fiber cells, vessels, resin canals, and ray cells that vary in composition and structure in the earlywood, latewood, sapwood, and heartwood domains, there is a tremendous variety of bonding surfaces, each of which may interact differently with the adhesives. The most dramatic difference is often between wood species because of the large difference in cellular architecture. Bonding of different species often requires changes in adhesive formulation to control penetration into the wood. Although some work has been done on determining penetration into cell lumens and walls [6], this information is usually not related to the performance of the bonded assembly. 

The second major area for cast products is in such architectural units as simulated marble sink tops, wall plaques, and decorative sculpture. For these products the preferred materials are polyester and acrylic recipes which contain large amounts of mineral fiber such as marble dust, clay, and chalk. These parts are usually made by casting into closed molds using fairly low viscosity mixtures with room temperature curing catalysts. Large parts measuring up to 8 feet square with thicknesses ranging from 1 /16 to 1/2 inch thick can be made and... 

Based on their histologic architecture, the arteries can be divided into four different groups elastic arteries, medium-sized muscular arteries, small arteries, and arterioles (i.e. the radial and ulnar arteries belong to the medium-sized muscular group). Elastic arteries are the largest in the body they expand when the heart contracts and return to a normal caliber in diastole. Muscular arteries are small and middle-sized vessels with a relatively narrow lumen and thick walls consisting of circumferentially arranged smooth muscle fibers which restrict the lumen when they contract. The... 

Co-electrospinning has been applied so far for the preparation of polymer core shell fibers, hollow polymer core shell fibers, hollow fibers composed not only of polymers, but also of ceramics, as well as for the immobilization of functional objects in droplets dispersed in the core that are arranged along the fiber axis. Among the examples reported in the literature are core shell fibers spun from polystyrene and polyethylene oxide, two kinds of polyethylene oxide (one with and the other without a chromophore), and core shell fibers with the electrically conductive polymer polyhexathiophene and the insulation polymer polyethylene oxide (Fig. 20). Hollow core shell fibers in which one polymer (polycaprolactone) forms the shell onto which the core material is deposited (polyethylene oxide) as inner wall is another example for the broad spectrum of fiber architectures which can be produced by coelectrospinning. The formation of the two-layer hollow fiber is based on the... 

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