14 research outputs found

    Tribological behaviour and internal stress of diamond coating deposited with a stationary d.c. plasma jet

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    A diamond coating was produced by a stationary d.c. plasma jet in a cofined circular area. Using scanning electron microscopy, optical microscopy, laser profilometry and Raman spectroscopy, it was found that the diamond coated area is inhomogeneous with respect to morphology, purity, thickness, and internal stress. Surrounding the diamond coated central area, an amorphous carbon rich area was identified. The morphologically distinct regions were evaluated separately in a fretting wear test against a corundum counterbody. The frictional behaviour was observed to be dependent on the morphology and structure of the coating and the diamond crystal size and orientation in the diamond coated area. No evidence of any fretting wear damage was found in the diamond coated area, whereas a lot of fretting induced scratches were observed in the amorphous carbon rich area. The presence of wear debris was clearly observed in the fretting contacts both inside and outside the diamond coated area.status: publishe

    Exploiting Cryptography for Privacy-Enhanced Access Control -- A result of the PRIME Project

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    We conduct more and more of our daily interactions over electronic media. The EC-funded project PRIME (Privacy and Identity Management for Europe) envisions that individuals will be able to interact in this information society in a secure and safe way while retaining control of their privacy. The project had set out to prove that existing privacy-enhancing technologies allow for the construction of a user-controlled identity management system that comes surprisingly close to this vision. This paper describes two key elements of the PRIME identity management systems: anonymous credentials and policy languages that fully exploit the advanced functionality offered by anonymous credentials. These two key elements enable the users to carry out transactions, e.g., over the Internet, revealing only the strictly necessary personal information. Apart from presenting for the first time these two key results, this paper also motivates the need for privacy enhancing identity management, gives concrete requirements for such a system and then describes the key principles of the PRIME identity management solution

    Protein citrullination and NET formation do not contribute to the pathology of A20/TNFAIP3 mutant mice

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    Abstract: A20 serves as a critical brake on NF-kappa B-dependent inflammation. In humans, polymorphisms in or near the TNFAIP3/A20 gene have been linked to various inflammatory disorders, including systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Experimental gene knockout studies in mice have confirmed A20 as a susceptibility gene for SLE and RA. Here, we examine the significance of protein citrullination and NET formation in the autoimmune pathology of A20 mutant mice because autoimmunity directed against citrullinated antigens released by neutrophil extracellular traps (NETs) is central to the pathogenesis of RA and SLE. Furthermore, genetic variants impairing the deubiquitinase (DUB) function of A20 have been shown to contribute to autoimmune susceptibility. Our findings demonstrate that genetic disruption of A20 DUB function in A20 C103R knockin mice does not result in autoimmune pathology. Moreover, we show that PAD4 deficiency, which abolishes protein citrullination and NET formation, does not prevent the development of autoimmunity in A20 deficient mice. Collectively, these findings provide experimental confirmation that PAD4-dependent protein citrullination and NET formation do not serve as pathogenic mechanisms in the development of RA and SLE pathology in mice with A20 mutations
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