Seroprevalence of 34 Human Papillomavirus Types in the German General Population

The natural history of infections with many human papillomavirus (HPV) types is poorly understood. Here, we describe for the first time the age- and sex-dependent antibody prevalence for 29 cutaneous and five mucosal HPV types from 15 species within five phylogenetic genera (alpha, beta, gamma, mu, nu) in a general population. Sera from 1,797 German adults and children (758 males and 1,039 females) between 1 and 82 years (median 37 years) were analysed for antibodies to the major capsid protein L1 by Luminex-based multiplex serology. The first substantial HPV antibody reactions observed already in children and young adults are those to cutaneous types of the genera nu (HPV 41) and mu (HPV 1, 63). The antibody prevalence to mucosal high-risk types, most prominently HPV 16, was elevated after puberty in women but not in men and peaked between 25 and 34 years. Antibodies to beta and gamma papillomaviruses (PV) were rare in children and increased homogeneously with age, with prevalence peaks at 40 and 60 years in women and 50 and 70 years in men. Antibodies to cutaneous alpha PV showed a heterogeneous age distribution. In summary, these data suggest three major seroprevalence patterns for HPV of phylogenetically distinct genera: antibodies to mu and nu skin PV appear early in life, those to mucosal alpha PV in women after puberty, and antibodies to beta as well as to gamma skin PV accumulate later in life

Influence of Thermal Oxide Layers on the Hydrogen Transport through the Surface of SAE 1010 Steel

Most research on the hydrogen embrittlement of steel dealt with the interaction of hydrogen with the metal bulk microstructural features, whereas the first contact with hydrogen-containing environments occurs at the metal surface. Steel (when un-polarized) is always covered with an oxide layer, varying in composition and thickness. The impact of the oxide layer on the hydrogen transport is, however, not fully understood. This study focused on the effect of controlled pre-formed thermal oxide layers at the exit side on the hydrogen transport through the surface of SEA 1010 steel, considering two distinct thermally produced oxide types as test cases. Results demonstrated that thermal oxides can greatly limit hydrogen diffusion, with bilayers (hematite/magnetite) having a greater effect compared to magnetite layers. Increased oxide thickness resulted also in greater limiting diffusion. The main objective of this manuscript is to provide experimental evidence concerning the effect of oxide layers on the hydrogen transport through steel. Model thermal oxide layers were used to emphasize the importance of considering the surface characteristics when investigating hydrogen transport through metallic components

Scanning Kelvin probe force microscopy study of the effect of thermal oxide layers on the hydrogen release - Experiments and finite element method modelling

International audienceScanning Kelvin Probe Force Microscopy (SKPFM) was used to study the hydrogen diffusion through a surface designed for simultaneous mapping of multiple areas containing different thermal oxides, all covered with Pd. Potential maps were obtained simultaneously on an area of bare iron as the reference, an area covered with a bilayer oxide (inner magnetite and outer hematite) and an area covered with a magnetite layer (obtained by removing the outer hematite layer of a bilayer oxide). After hydrogen charging at the bottom side of the specimen, a contrast was obtained in the potential mapping on the covering Pd layer due to differences in hydrogen release through these distinct areas on the specimen surface. A finite element method (FEM) model of hydrogen diffusion across the different phases was developed to simulate the experiment. The modelling showed that both a lower diffusion coefficient and a lower solubility in the oxide can explain the contrast obtained in SKPFM. Cross diffusion in the ferritic bulk underneath the thermal oxide was found to have an influence on the spatial distribution of the hydrogen release