Medical applications fibers

Novel Optical Fiber Techniques for Medical Applications", A. Katzir, Ed. Proc. SPIE, 494, (1984)... 

Medical applications of biodegradable shape memory polymers include their use for removing blood clots formed during strokes. Preshaped foams can be used to fill cranial aneurisms. Loosely tied sutures made from fibers that have been stretched at 50 °C will tighten when heated just above room temperature. 

Raman spectroscopy failed to live up to its original expectation when the technique was discovered. This was due to instrumental problems, high cost of the instrument, and the fluorescence problem. However, with improvement in instrumentation, the use of a near infrared laser with FT-Raman, the introduction of fiber optics, the number of applications (some of which were discussed in Chapter 3) has escalated. The applications are expanded in this chapter, which deals with materials applications involving structural chemistry, solid state, and surfaces. Additional applications are presented in Chapter 5 (analytical applications), Chapter 6 (biochemical and medical applications) and Chapter 7 (industrial applications). 

Lignocellulosic research today is poised on the threshold of a new era of research breakthroughs. It has enabled the use of a wide variety of lignocellulosic materials, low-quality wood species and sawdust, and low-value lignin products. Lignocellulosic and cellulosic research efforts are under way to produce novel products for construction, transportation, plastics, fiber, packaging, and medical applications. Some of the major activities in chemical modifications of wood, cellulose, and lignins are the main features of this book. 

Fiber characteristics that should be taken into account for making filters include temperature capability, corrosion resistance (withstand adds, alkalies, solvents, etc.), hydrolysis (humidity levels), dimensional stability, and cost. Among important medical application of fibers, we should mention sutures and filters. Sutures are used to close the wound during surgical operations. Fibers used as sutures can be absorbable or nonabsorbable. The main requirements are that the suture must have only a minimal amount of reaction with the tissue and, in the case of absorption, there must be minimal chemical irritation (Lyman,... 

Hollow membrane fibers are required for many medical application, e.g. for disposable dialysis. Such fibers are made by usmg an appropriate fiber spinning technique with a special inlet in the center of the spinneret through which the fiber core forming medium (liquid or gas) is injected. The membrane material may be made by melt-spinning, chemical activated spinning or phase separation. The thin wall (15-500 xm thickness) acts as a semi-permeable membrane. Commonly, such fibers are made of cellulose-based membrane materials such as cellulose nitrate, or polyacrylonitrile, polymethylmethacrylate, polyamide and polypropylene (van Stone, 1985). 

Examples of nir analysis are polymer identification (126,127), pharmaceutical manufacturing (128), gasoline analysis (129,130), and on-line refinery process chemistry (131). Nir fiber optics have been used as immersion probes for monitoring pollutants in drainage waters by attenuated total internal reflectance (132). The usefijlness of nir for aqueous systems has led to important biological and medical applications (133). 

Carbon fibers are flexible enough to permit implantation in a number of tissues, including the wall of the intestine [138]. However, sharp angles must be avoided, since the fibers will break and their small diameter makes them difficult to handle. Table 6 gives examples of conducting devices in medical applications. 

Major polymer applications aircraft interiors, multipin connectors, coil bobbins, integrated circuits sockets, fiber optics connectors, dip switches, automotive fuses, printed circuit boards, transformer wire coatings, microwave cookware, sight glasses, membranes, medical applications (due to the resistance to different methods of sterilization), coatings... 

Major polymer applications optical fibers, dials, optical components, household items, car rear lights, artificial stones (filled products) for injection molded bath sinks, and kitchen worktops, bone cement, composites, medical applications (e.g. bone cement)... 

Chitin is known to be biodegradable, biocompatible, and nontoxic. It is used in dmg delivery and bio medical applications. It also used in the purification of water especially for the absorption of toxic dyes. Chitin has limited solubility in solvents but chitosan is readily soluble in acidic aqueous solutions and has more tendency to be chemically modified. Chitosan can readily be spun into fibers, cast into films, or precipitated in a variety of micromorphologies from acidic solutions. Min and Kim have reported on the adsorption of acid dyes from wastewater using composites of PAN/chitosan [52]. Shin et al. has reported on copolymers composed of PVA and poly dimethyl siloxanes cross-linked with chitosan to prepare semi IPN hydrogels for application as biomedical materials... 

Polyesters are in widespread use in our modern life, ranging from bottles for carbonated soft drinks and water, fibers for shirts and other apparel, to the base for photographic film and recording tape. Household tradenames, such as Dacron , Fortrel , Terylene , Mylar , etc. demonstrate the ubiquitous nature of polyesters. In addition, of the biodegradable polymers employed in medical applications, polyesters are most often used. 

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