The Influence of Inert Packaging on the shelf Ageing of Gamma-Irradiation Sterilised ultra-high molecular weight polyethylene

Ultra-high molecular weight polyethylene (UHMWPE) is used for wear applications in total hip prostheses and total knee prostheses. Sterilisation of these prostheses is commonly by gamma-irradiation. This process creates reactive free radicals in the UHMWPE, greatly increasing its susceptibility to oxidative degradation. This study has investigated the influence of air and vacuum packaging on the properties of gamma-irradiated UHMWPE (GUR1050) following 3 years of shelf ageing. The findings indicate that vacuum packaging minimises oxidative degradation reactions that occur for UHMWPE during shelf ageing. However, gamma-irradiation of vacuum-packaged UHMWPE promotes a degree of cross-linking. It is proposed that this may enhance the wear performance of UHMWPE. Accelerated ageing studies indicate that 3 years of shelf ageing would also seem to reduce the susceptibility of gamma-irradiated UHMWPE to oxidative degradation upon removal from its vacuum packaging.

Is Northern Ireland abnormal? An extension of the sociological debate on religion in modern Britain

This article places Northern Ireland within the unfolding sociological debate on religion in modern Britain. It measures secularization along Casanova’s three dimensions (1994): religious differentiation, decline and privatization. It finds that Northern Ireland has, in common with Britain, high levels of religious differentiation, grey areas of religious belief and little convinced secularism. However, Northern Ireland differs in that it has higher levels of religious affiliation and practice, and religion plays more roles in civil society than it does in other parts of Britain. The article explores the role of conflict in forming these religious trends, asking if they represent a persistence of the sacred, or simply mask deeper ethnic divisions. It concludes that the social dimensions of religion are just as important as the supernatural, and that they often inform each other. Finally, it suggests that the dynamics of religious change are comparable across regions and, as such, Northern Ireland might be a useful case study for British policy makers, particularly as it becomes increasingly multicultural and religiously plural.