Fiber side branching

Fig.3.5. The anchor technique. This technique is very valuable for providing safe and distal occlusion when there is a question about instability of pushable fibered coils. Diagrammatically, the guide catheter is placed in the artery to be occluded and a 5-F inner catheter or microcatheter is advanced into a side branch next to the site requiring occlusion. At least 2 cm of a 14-cm standard Nester or Micronester are advanced into the side branch which is normally sacrificed. The rest of the coil is then deployed just proximal to that side branch and additional coils are packed so that cross-sectional occlusion is obtained...

Figure 2.8 Surfactant-enhanced tip branching (a,b) and side branching (c-e) of GP-1 fibers formed in solvent isostea7l alcohol (ISA) (a,b) and propanol glycol (PC) (c-f). (g,h,i) illustrate the surfactant...

Enhanced side branching of fibers by surfactant molecules was also observed. It was observed that the presence of a surfactant Span 20 could enhance the side branching of GP-1 fibers formed in propylene glycol (PG), which converts spherulitic fiber structures into comb-like and brush-like fibers when the surfactant concentration is below 0.77 wt% (Figure 2.8c-e) [4a]. With increase of surfactant concentration to above its critical micelle concentration (CMC) of 1.5 wt% in PG, the fiber network was converted back into a spherulitic fiber network (Figure 2.8f). However, the spherulitic fiber network formed in the presence of the surfactant is denser, and the elasticity of the material is twice that in the absence of surfactant. 

However, polymers with long flexible side groups or branches are difficult to form molecular orientation, and hence they are seldom used to make polymer fibers. Side groups found in polymer fibers typically are rigid and they can raise the... 

Other distinct classes of wood in a tree include the portion formed in the first 10—12 years of a tree s growth, ie, juvenile wood, and the reaction wood formed when a tree s growth is distorted by external forces. Juvenile fibers from softwoods are slightly shorter and the cell walls thinner than mature wood fibers. Reaction wood is of two types because the two classes of trees react differentiy to externally applied stresses. Tension wood forms in hardwoods and compression wood forms in softwoods. Compression wood forms on the side of the tree subjected to compression, eg, the underside of a leaning tmnk or branch. Tension wood forms on the upper or tension side. Whereas in compression wood, the tracheid cell wall is thickened until the lumen essentially disappears, in tension wood, tme fiber lumens are filled with a gel layer of hemiceUulose. 

Using computer modeling, jointly with x-ray fiber diffraction data, the molecular architectures of two different gel-forming polysaccharides have been examined. Preliminary results indicate that the neutral and doubly branched capsular polysaccharide from Rhizobium trifolii can form a 2-fold single helix of pitch 1.96 nm or a half-staggered, 4-fold doublehelix of pitch 3.92 nm. The molecules are likely to be stabilized by main chain — side chain interactions. 

Bundles will be absent. Branching fibers are unlikely. If branching occurs, the separation point will be clearly defined. Fibers will probably be thick compared to asbestos. All fibers, including thick fibers, will show no reaction with polarized light. Breaks in fibers may resemble a break in a glass rod with a chip on one side. 

Cardiac muscles, as is evident from their name, make up the muscular portion of the heart. While almost all cardiac muscle is confined to the heart, some of these cells extend for a short distance into cardiac vessels before tapering off completely. The heart muscle is also called the myocardium. The heart muscle is responsible for more than two billion beats in a lifetime. The myocardium has some properties similar to skeletal muscle tissue, but it is also unique. Like skeletal muscles, myocardium is striated however, the cardiac muscle fibers are smaller and shorter than skeletal muscle fibers averaging 5-15 micrometers in diameter and 20-30 micrometers in length. In addition, cardiac muscles align lengthwise more than side-by-side compared to skeletal muscle fibers. The microscopic structure of cardiac muscle is also unique in that these cells are branched such that they can simultaneously communicate with multiple cardiac muscle fibers. 

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