Application implantation

Flexible PI electrode microelectrode arrays have been developed for electric potential probing for in vivo applications. Implantable micro-... 

In this entry are discussed a few of the specialized batteries for medical devices that are portable or wearable (carried with the patient, like hearing aids), or implantable (surgically placed inside the body as with neurostimulation pain management devices). There is a focus on the batteries designed for a few of the more common applications - implantable cardiac rhythm management (cardiac pacemakers and defibrillators), pain management, and hearing loss devices. 

As a result, many nuclear and industrial applications have been developed for zirconium and its alloys. These applications include fuel cladding and pressure tubes for nuclear reactors, process equipment for the CPI, superconducting materials, battery alloys, hydrogen storage alloys, ordnance applications, implant materials, and consumer goods. 

Uses. The chemical inertness, thermal stability, low toxicity, and nonflammability of PFCs coupled with their unusual physical properties suggest many useflil applications. However, the high cost of raw materials and manufacture has limited commercial production to a few, small-volume products. Carbon tetrafluoride and hexafluoroethane are used for plasma, ion-beam, or sputter etching of semiconductor devices (17) (see loN implantation). Hexafluoroethane and octafluoropropane have some applications as dielectric gases, and perfluorocyclobutane is used in minor amounts as a dielectric fluid. Perfluoro-1,3-dimethyl cyclohexane is used as an inert, immersion coolant for electronic equipment, and perfluoro-2-methyldecatin is used for... 

Biomedical Applications. In the area of biomedical polymers and materials, two types of appHcations have been envisioned and explored. The first is the use of polyphosphazenes as bioinert materials for implantation in the body either as housing for medical devices or as stmctural materials for heart valves, artificial blood vessels, and catheters. A number of fluoroalkoxy-, aryloxy-, and arylamino-substituted polyphosphazenes have been tested by actual implantation ia rats and found to generate Httle tissue response (18). 

Aliphatic isocyanates have a small but growing market application in thermoplastic polyurethanes (TPU). Medical appflcafions include wound dressings, catheters, implant devices, and blood bags. A security glass system using light-stable TPU as an inner layer is under evaluation for shatterproof automotive windshield appflcafions. 

The complexity of the apparatus needed for ion implantation makes this method of case hardening of limited application. Further, the case depth is considerably lower than that produced by carburizing or nitriding. The depth of implantation of nitrogen in a steel is about 0.00006 cm (19), ie, so thin that it is difficult to measure the hardness profile by conventional microhardness measurements. 

The improvement in wear resistance from ion implantation is shown in Figure 10 (20). However, the thin case cannot sustain very heavy loads. Hence this application for improved wear resistance is limited to special situations, eg, low loads. 

J. B. Pallix, C. H. Becker, and K. T. Gillen, Appl. Surface Sck 32,1 (1988). An applications oriented discussion of using MPI-SALI for depth profiling, interface analysis in inorganic material systems. Examples of SALI depth profiles are given of a B implant in Si and the fluorine implanted electronic test device which was referenced in this encyclopedia article. 

Silicone mbbers have been widely used for medical applications, particularly for body implants in structural cosmetic surgery. One high-profile application has been that of breast implants, but the award in early 1994 of enormous damages by a US court in respect of faulty implants may discourage development of this application. 

Recent applications of e-beam and HF-plasma SNMS have been published in the following areas aerosol particles [3.77], X-ray mirrors [3.78, 3.79], ceramics and hard coatings [3.80-3.84], glasses [3.85], interface reactions [3.86], ion implantations [3.87], molecular beam epitaxy (MBE) layers [3.88], multilayer systems [3.89], ohmic contacts [3.90], organic additives [3.91], perovskite-type and superconducting layers [3.92], steel [3.93, 3.94], surface deposition [3.95], sub-surface diffusion [3.96], sensors [3.97-3.99], soil [3.100], and thermal barrier coatings [3.101]. 

Filtering cells and cell fractions from fluid media. These particles, after concentration by filtration, may be examined through subsequent quantitative or qualitative analysis. The filtration techniques also have applications in fields related to immunology and implantation of tissues as well as in cytological evaluation of cerebrospinal, fluid. 

Several other polymers, non-metals and ceramics, are currently being implanted for applications outside orthopaedic surgery, typical examples... 

It is widely appreciated that the deterioration of metal and plastic implant materials within the body is one of the most important aspects of implant surgery. This particular application of materials places an almost unique demand on the resistance to deterioration. The reasons are basically twofold, for not only may the environmental effects alter the structure and properties of the material, which may itself affect the function of the implant and hence the well-being of the patient, but also the by-products of any structural change may have harmful effects on the patient... 

Material Type and condition Typical standard for implant application Ultimate tensile strength M Pa min 0.2% tensile yield stress M Pa Young s modulus X lO M Pa Elongation at fracture % min Compressive strength M Pa Vickers hardness Fatigue strength (10 cycles) M Pa... 

A rapidly growing use in the medical field is for surgical implants as either bone plates and screws, joint replacements, or for the repair of cranial injuries. Here, titanium and its alloys have the advantages of complete compatibility with body fluids, low density, and low modulus. Applications also exist in dentistry. 

Applications Ion implantation is widely employed to improve the life of tools. Thus press tools, dies and gear cutters can be treated to increase their durability by three times or more. Nitrogen-implanted tungsten carbide drawing dies for copper and iron wire can be improved up to fivefold. By implanting chromium, aluminium or silicon a considerable increase in the corrosion resistance of steel can be obtained. Implantation of chromium into aircraft bearing alloys has improved their durability in marine environments . 

Proc. Symp. on Power Sources for Biomedical Implantable Applications and Ambient Temperature Lithium Batteries (Eds. B. G. Owens, N. Margalit), The Electrochemical Society Proceeding Series, PV 80-4, The Electrochemical Society, Princeton, NJ 1980, p. 321. [561 V. R. Koch, J. Electrochem. Soc, 1979, 126, 181. 

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