Epidemiology of HIV-1 subtypes in an urban area of northern Italy.

The distribution of the different subtypes of HIV varies from one region of the world to another. Subtype B is predominant in Europe and the USA, but there has been a gradual increase in non-B subtypes as a result of migration from regions where they are endemic, and this may have important implications for the control of HIV-1. The aim of this study was to assess the prevalence of HIV-1 subtypes in an urban area of northern Italy in the period 1997-2008. Forty-nine (12.2%; 95% CI, 9.00-15.40) of 401 patients investigated carried a non-B subtype, the prevalence of which was 7.7% (95% CI, 4.96-10.44) among native Italians and 55.3% (95% CI, 39.49-71.11) among non-Italians, 1.6% (95% CI, 0.00-3.81) among ex-intravenous drug addicts, 7.6% (95% CI, 1.21-13.99) among homosexual/bisexual men and 20.5% (95% CI, 14.83-26.17) among heterosexuals, 6.8% (95% CI, 3.37-10.23) among Italians infected as a result of sexual contacts in Italy, and 55.0% (95% CI, 33.20-76.80) among Italians infected abroad or by foreign partners. Overall prevalence increased from 2.9% (95% CI, 0.00-6.11) before 1993 to 23.0% (95% CI, 16.31-29.69) in the period 2001-2008. The results demonstrate that there has been an increase in non-B subtypes (especially sexually transmitted infections), particularly among patients infected abroad or by foreign partners.

X-ray diffraction microtomography (XRD-CT), a novel tool for non-invasive mapping of phase development in cement materials.

A recently developed synchrotron-based imaging technique, X-ray diffraction microtomography (XRD-CT), has been applied here for the first time to a complex system, the hydrating Portland cement paste, in order to monitor the evolution of microstructure and phase formation with a 3D non-invasive imaging approach. The ettringite-XRD-peak-based image reconstructions, combined with transmission microtomography (X-microCT) images, allowed to assess the ubiquitous distribution of this phase, which appears early in the hydration process and showed its preferential concentration in the relatively less compact regions of the paste. The comparison of greyscale histograms for cement pastes after 9 and 58 h from hydration showed an increase of ettringite content with age, in agreement with the quantitative Rietveld analysis of the sum patterns. By renormalizing the greyscale histograms to the relative weight fraction, as obtained from Rietveld refinements, a new technique which allows estimation of phase contents with spatial resolution has been developed. The results achievable by combining XRD-CT, X-microCT and Rietveld appear very promising to provide experimental snapshots of the cement hydration process to be compared with results obtained from computer simulations.