Plasmonic ELISA for the detection of gp120 at ultralow concentrations with the naked eye.

The technique of plasmonic ELISA is utilised here to detect the HIV-1 protein gp120 with the ultralow limit of detection of 8 × 10(-20) M (10(-17) g mL(-1)) in an independent laboratory. It was corroborated that changes in the concentration of hydrogen peroxide as small as 0.05 µM could lead to nanoparticle solutions of completely different tonality.

Rural:urban inequalities in post 2015 targets and indicators for drinking-water.

Disparities in access to drinking water between rural and urban areas are pronounced. Although use of improved sources has increased more rapidly in rural areas, rising from 62% in 1990 to 81% in 2011, the proportion of the rural population using an improved water source remains substantially lower than in urban areas. Inequalities in coverage are compounded by disparities in other aspects of water service. Not all improved sources are safe and evidence from a systematic review demonstrates that water is more likely to contain detectable fecal indicator bacteria in rural areas. Piped water on premises is a service enjoyed primarily by those living in urban areas so differentiating amongst improved sources would exacerbate rural:urban disparities yet further. We argue that an urban bias may have resulted due to apparent stagnation in urban coverage and the inequity observed between urban and peri-urban areas. The apparent stagnation at around 95% coverage in urban areas stems in part from relative population growth - over the last two decades more people gained access to improved water in urban areas. There are calls for setting higher standards in urban areas which would exacerbate the already extreme rural disadvantage. Instead of setting different targets, health, economic, and human rights perspectives, We suggest that the focus should be kept on achieving universal access to safe water (primarily in rural areas) while monitoring progress towards higher service levels, including greater water safety (both in rural and urban areas and among different economic strata).