Wear particles biological activity

Determining the volumetric concentration of wear particles in each size range for each material or device and then integrating these values with the biological activity function for UHMWPE allows the SBA for each material or device tested to be determined. The SBA can then be integrated with the volumetric wear rate (in mmVmillion cycles) to give a measure of functional biological activity (FBA),... 

The osteolytic potential of the wear particles generated in the hip and knee simulators was predicted using the method of Fisher et al. [61] to calculate functional biological activity (FBA) as previously described. The values of SBA and FBA were compared for the wear particles from the two UHMWPEs in both the hip and knee simulations. 

The wear rates, sizes and morphologies of the wear particles together with the predicted biological activity indices for both the hip and knee prostheses are reported below. 

The volumetric concentrations of wear particles in the different size ranges had a marked effect on the biological activity indices for the different UHMWPEs and the prostheses. In the hip, the SBA of the GUR 1050 25kGy UHMWPE was markedly higher than the GUR 1020 GVF UHMWPE, at 0.89 compared to 0.51 (Table 27.2). This increase in SBA can be accounted for by the much higher volumetric concentration of wear particles in the more... 

Protection against airborne radioactive particles is a problem in the nuclear industry. Microfilament yams may be densely woven to produce fabrics with maximum pore size of 20-30 pm for use in the nuclear industry compared with the 75-300 pm pore size of typical cotton and polyester cotton fabrics. Incorporation of filaments with a carbon core greatly reduces the atttaction of radioactive particulates by static electricity on to the fabric during wear, as does the inclusion of an absorbing activated carbon layer as used in nuclear, biological and chemical (NBC) suits in military use (see Section 10.3.3.4). 

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