Fiber protrusion

Fig. 3.14. Schematic drawings of slice compression test on a single fiber composite (a) before loading (b) peak loading with a maximum fiber protrusion length, (c) after unloading with a residual fiber protrusion length, After Hsueh (1993),...

In the light of these observations the interest of laser surface treatment is evident in terms of wettabihty, roughening, surface cleaning, and chemical modification. The use of two different adhesives makes it possible to check the relative effects of laser treatment on polymer modification as well as on fiber protrusion. When a cohesive failure inside the material is obtained after classical surface treatment, laser ablation makes it possible to improve the mechanical behavior by reaching the fiber reinforcement itself... 

The principles of the push-pull model probably apply generally to amoeboid cell motility. Indeed, a consensus is developing that in both sperm and actin-based crawling cells the force for protrusion is derived from localized cytoskeletal assembly (reviewed by Pollard and Borisy, 2003). However, as applied to nematode sperm locomotion, the model envisions that lamellipod extension and cell body retraction are linked reciprocally to the polymerization state of the cytoskeleton. The lack of structural polarity of MSP filaments, the precise localization of cytoskeletal polymerization and depolymerization at opposite ends of the fiber complexes, and insights gained from reconstitution of cytoskeletal dynamics and motility in vitro and in vivo all support the conclusion that nematode sperm move without using motor proteins and that, instead, they rely on... 

Stewart etal., FIg. 12. The interaction between the integrin proximal domain and the Adl2 penton base protein. (A) The integrin density is shown extracted along estimated boundaries to model the proximal domain of one integrin heterodimer and shown with the penton base and fiber. (B) The modeled proximal domain rotated to showtheinteractionwithasingle penton base protrusion. (G) The same view as in (B),but with the protrusion removed to reveal the RGD-binding cleft. The color scheme is the same as in Fig. 11. Scale bars 25 A. [Reproduced with permission from Chiu etal. (1999).]... 

The Rho family of small GTP-binding proteins functions to regulate the assembly of distinct actin structures in cells Rho regulates stress fiber assembly, Rac regulates lamellipodia protrusion and Cdc42 stimulates protrusion of the plasma membrane to form filopodia (Ridley and Hall, 1992 Ridley et at., 1992 Nobes and Hall, 1995 Kozma et at., 1995). All three regulate attachment of cells to the extracellular matrix via adhesive integrin structures (Nobes and Hall, 1995). 

Microfilaments, which are small (5-7 nm in diameter) fibers composed of the protein actin, perform their functions by interacting with certain cross-linking proteins. Important roles of microfilaments include involvement in cytoplasmic streaming (a process that is most easily observed in plant cells in which cytoplasmic currents rapidly displace organelles such as chloroplasts) and ameboid movement (a type of locomotion created by the formation of temporary cytoplasmic protrusions). 

Mesenchymal cells are spherical when in suspension and form stable protrusions only upon attachment to a surface [15]. The cells can adhere tightly to the substratum in tissue culture utilizing structures termed focal adhesions [26]. Upon extension of a lamellipod, close contacts to the substratum form, which then convert into localized adhesive clusters that can be detected using interference reflection microscopy [107, 166], These focal contacts have clusters of transmembrane proteins termed integrins that bind to extracellular matrix molecules and link intracellularly to the actin cytoskeleton to form stress fibers [251]. Adhesion to the substratum is necessary for stabilization of the lamellipod if a lamellipod extends over a nonadhesive surface, it then retracts [14],... 

Milwich et al. (2006) combined ideas of cellulose fiber orientation in wood with the structure of the stem of giant reeds to create a hybrid model realized using advanced braid protrusion machinery at the Institute of Textile Technology and Process Engineering (ITV) Germany. The outcome called Technical Plant Stem is a commercially scalable architectural textile composite that demonstrates excellent strength and impact resistance with the minimal material use (Speck and Speck, 2006). 

The researchers observed a series of nanoprotrusions from spikes to blocks oriented perpendicular to the fiber axis. The mechanism for this process was similar to the crystallization mechanism of CNT growth from a surface. Carbon nanostructures from electrospun carbon nanofibers with iron and palladium nanoparticles were grown, respectively. In a later work, the type of carbon dictated the morphology of the resulting nanostructure. Toluene as the carbon source yielded straight nanotubes, pyridine gave coiled and Y-shaped nanotubes, and chlorobenzene formed nanoribbons. Figure 8.4 displays a variety of carbon nanostructures from rods to Y-shaped protrusions. 

The ACL conies into adjacency with the anterior horn of the lateral meniscus under gross observation, and parts of the ACL fiber are attached to the anterior horn with an anterior width ranging from 1/3-1/2 of its surface. Moreover, fat and scar tissues cover its border, and the border between the anterior horn of the lateral meniscus and ACL attachment cannot be grossly identified. When these surface layers of soft tissues are carefully detached, both structures are overlapped anteriorly and the lateral meniscus slips under the substratum of the ACL posteriorly (Fig. 4.3). The anterior horn of the lateral meniscus was attached on the base of the lateral groove and lateral aspect of the aforementioned bony protrusion, and the attachment was... 

Addition of Si02 NPs into electrospim fibers was found to change fiber surface topography and roughness by creating wrinkles and nanoscaled protrusions on the surface of the nanofibers. Such fibers can find useful application as air filtration media with improved performances [15]. 

The second stage is the stage of successive process of stretching and whipping, evaporation of most of the solvent(s) used, migration of most of the distance between the spinneret and the collector, and finally a decrease in the fiber diameter. The third stage is known as the splay stage since it involves the protrusion of several strands out of the main polymer jet. 

Although the ability of carbon to form multiwall tubular nanostructures is well known and these tubes have been studied extensively, much less information is available about carbon nanotube structures having polygonal cross sections. An occurrence of polygonal vapor-grown carbon fibers with a core carbon nanotube protrusion was noted by Speck et al. ° as early as 1989, but no details were given about core fiber structure and its polygonization. 

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