Small-diameter fibers

The adherence and proliferation of human umbilical vein endothelial cells (HUVECs) were evaluated on the fabricated PCLA scaffold. Results showed that the HUVECs were adhered and proliferated well on the small-diameter-fiber fabrics (0.3 and 1.2 mm in diameter), whereas markedly reduced cell adhesion, restricted cell spreading, and no signs of proliferation were observed on the large-diameter-fiber fabric (7 mm in diameter). That may be due to the high-surface-density fibers provide an extremely high surface/volume ratio, which favors cell attachment and proliferation. 

Sato N., Kurauchi T., Sato, S. and Kamigaito O. (1988). Reinforcing mechanism by small diameter fiber in short fiber composite. J. Composites Mater. 22, 850-873. 

Local anesthetics preferentially block small fibers because the distance over which such fibers can passively propagate an electrical impulse is shorter. During the onset of local anesthesia, when short sections of a nerve are blocked, the small-diameter fibers are the first to fail to conduct electrical impulses. For myelinated nerves, at least two and preferably three successive nodes of Ranvier must be blocked by the local anesthetic to halt impulse propagation. Therefore, myelinated nerves tend to become blocked before unmyelinated nerves of the same diameter. For this reason, the preganglionic fibers are blocked before the smaller unmyelinated C fibers involved in pain transmission. 

Generation of synthetic elastin-mimetic small diameter fibers and fiber networks. Macromolecules 33, 2989-2997. 

Figure 6. Cross-sectional and longitudinal views of a diffuse-porous wood. Note in cross section that the vessels, the large diameter cells, are essentially the same size throughout the growth ring. Both longitudinal views reveal the vessels (V) are formed as the result of individual vessel cells stacked one on top of the other in the longitudinal direction. The majority of the remaining cells are small diameter fibers. 70 X (Courtesy of N. C. Brown Center for Ultra-structural Studies, S.U.N.Y. College of Environmental Science and Forestry)...

The only limitations of this method that are not also present in the classical method relate to the shape of the fiber. Although the above quantitative theory considers a cylindrical fiber, the method should work equally well (on a go-no go basis) for small diameter fibers of any cross section that do not have cusps pointed outward. Referring to Figure 2, irregular cross sections such as A, B, and C are satisfactory. A fiber of cross section D, however, must sink at contact angles much greater than... 

Strain of small diameter fibers can be determined at room temperature using noncontact laser methods.56 While the technique yields good results at room temperature, it is not clear that it is readily adaptable to higher temperatures without significant modifications in coupling fluid, and mounting methods and materials. 

Creep of fibers also occurs much more rapidly than happens in bulk materials, in part because of the much smaller grain sizes present in the fibers. Creep and creep rupture test techniques for composites are described elsewhere in this volume (Chapter 4 Weiderhom and Fuller) but performing such tests on small diameter fibers requires somewhat different apparatus.57 To date, only a small number of fiber compositions have been characterized.58... 

The inviscid jet must be stabilized in about 10 seconds or it will breakup into droplets. Yet another point in regard to this process is the fact that small diameter fibers are difficult to make. For example, the smallest diameter of an alumina-calda fiber produced by this technique is 105 xm. These fibers, according to the authors, have tensile strengths close to 1 GPa. 

Tiny fragments of carbon fiber, if released into the atmosphere, can pose a health hazard to human beings and can cause problems for electrical and electronic equipment. Some of these human health hazards are, as discussed in Chapter 6 with regard to asbestos fiber, common to all very small diameter fibers. They can cause skin and eye irritation and a variety of lung diseases. It turns out that in... 

Hollow fiber assembhes function as one-ended shell-and-tube devices. At one end the fibers are embedded in an epoxy tube-sheet and at the other end they are sealed. Overall flows of feed solution and permeate thus are in counterflow. Flow of permeate is into the tubes, which takes advantage of the great crushing strengths of the small diameter fibers. This also constitutes a... 

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