Atopic dermatitis and food sensitization in South African toddlers: Role of fiber and gut microbiota

The pathogenesis of atopic dermatitis (AD) is complex and related to allergic responses and defects in skin barrier function. In common with many atopic diseases, the prevalence of AD has been increasing across the world.1 One of the theories for this increase is increased hygiene and urbanization-related changes in the environment, which can affect the human microbiome.2 Previous studies have found associations between the composition of the early gut microbiome and development of atopic conditions, including AD.3 Although the rate of atopic conditions, including AD and food allergy, is increasing on all continents, the prevalence of these diseases is still lower in African countries.1 This is especially interesting because individuals of African origin who live in Western countries, such as African Americans, are at a higher risk for severe AD.4 This variation places Africa in a special position; studying African populations is necessary not only to find ways to prevent increases of allergy conditions in African countries but also to provide important clues to the causes of this global increasing of allergic conditions. Young children who have developed AD in African communities with a low incidence of atopic disease might be the transitional group. In the current study, we have, for the first time to our knowledge, analyzed the fecal microbiota composition of a group of young black African children aged 12 to 36 months old with and without AD living in the same community in Cape Town, South Africa. Our primary goal was to examine whether toddlers with AD and control toddlers from Cape Town have different microbiomes in terms of bacterial richness and diversity. We also aimed to investigate the differences in the relative abundance for different operational taxonomic units between these 2 groups. In our subgroup analyses, we further tested the effect of multiple environmental factors on the gut microbiome in these children

European Atlas of Natural Radiation

Natural ionizing radiation is considered as the largest contributor to the collective effective dose received by the world population. The human population is continuously exposed to ionizing radiation from several natural sources that can be classified into two broad categories: high-energy cosmic rays incident on the Earth’s atmosphere and releasing secondary radiation (cosmic contribution); and radioactive nuclides generated during the formation of the Earth and still present in the Earth’s crust (terrestrial contribution). Terrestrial radioactivity is mostly produced by the uranium and thorium radioactive families together with potassium. In most circumstances, radon, a noble gas produced in the radioactive decay of uranium, is the most important contributor to the total dose. This Atlas aims to present the current state of knowledge of natural radioactivity, by giving general background information, and describing its various sources. This reference material is complemented by a collection of maps of Europe displaying the levels of natural radioactivity caused by different sources. It is a compilation of contributions and reviews received from more than 80 experts in their field: they come from universities, research centres, national and European authorities and international organizations. This Atlas provides reference material and makes harmonized datasets available to the scientific community and national competent authorities. In parallel, this Atlas may serve as a tool for the public to: • familiarize itself with natural radioactivity; • be informed about the levels of natural radioactivity caused by different sources; • have a more balanced view of the annual dose received by the world population, to which natural radioactivity is the largest contributor; • and make direct comparisons between doses from natural sources of ionizing radiation and those from man-made (artificial) ones, hence to better understand the latter.JRC.G.10-Knowledge for Nuclear Security and Safet

Chapter 5: Radon

Natural ionising radiation is considered the largest contributor to the collective effective dose received by the world’s population. Man is continuously exposed to ionising radiation from several sources that can be grouped into two categories: first, high-energy cosmic rays incident on the Earth’s atmosphere and releasing secondary radiation (cosmic contribution); and, second, radioactive nuclides generated when the Earth was formed and still present in its crust (terrestrial contribution). Terrestrial radioactivity is mostly produced by the uranium (U) and thorium (Th) radioactive families together with potassium (40K), a long-lived radioactive isotope of the elemental potassium. In most cases, radon (222Rn), a noble gas produced by radioactive decay of the 238U progeny, is the major contributor to the total dose. This European Atlas of Natural Radiation has been conceived and developed as a tool for the public to become familiar with natural radioactivity; be informed about the levels of such radioactivity caused by different sources; and have a more balanced view of the annual dose received by the world’s population, to which natural radioactivity is the largest contributor. At the same time, it provides reference material and generates harmonised data, both for the scientific community and national competent authorities. Intended as an encyclopaedia of natural radioactivity, the Atlas describes the different sources of such radioactivity, cosmic and terrestrial, and represents the state-of-the art of this topic. In parallel, it contains a collection of maps of Europe showing the levels of natural sources of radiation. This work unfolds as a sequence of chapters: the rationale behind; some necessary background information; terrestrial radionuclides; radon; radionuclides in water and river sediments; radionuclides in food; cosmic radiation and cosmogenic radionuclides. The final chapter delivers the overall goal of the Atlas: a population-weighted average of the annual effective dose due to natural sources of radon, estimated for each European country as well as for all of them together, giving, therefore, an overall European estimate. As a complement, this introductory chapter offers an overview of the legal basis and requirements on protecting the public from exposure to natural radiation sources. In Europe, radiation has a long tradition. Based on the Euratom Treaty, the European Atomic Energy Community early established a set of legislation for protecting the public against dangers arising from artificial ('man-made') ionising radiation, but this scope has since been extended to include natural radiation. Indeed, the recently modernised and consolidated Basic Safety Standards Directive from 2013 contains detailed provisions on the protection from all natural radiation sources, including radon, cosmic rays, natural radionuclides in building material, and naturally occurring radioactive material