Numerical studies of tunneling in a nonharmonic time-dependent potential

Azbel' has recently carried out a WKB-analysis of the effects of a nonharmonic time-dependent perturbation embedded in an opaque potential barrier. He suggests the existence of three different transmission regimes: direct tunneling, activation assisted tunneling, and elevator resonant activation. We address the same problem with a numerical technique, and find qualitative agreement with Azbel's picture.Comment: LaTeX document, 15 pages. 4 figures (Fig. 2 comes in 7 pages) in postscript appended to the LaTeX documen

Prenatal exposures and exposomics of asthma

This review examines the causal investigation of preclinical development of childhood asthma using exposomic tools. We examine the current state of knowledge regarding early-life exposure to non-biogenic indoor air pollution and the developmental modulation of the immune system. We examine how metabolomics technologies could aid not only in the biomarker identification of a particular asthma phenotype, but also the mechanisms underlying the immunopathologic process. Within such a framework, we propose alternate components of exposomic investigation of asthma in which, the exposome represents a reiterative investigative process of targeted biomarker identification, validation through computational systems biology and physical sampling of environmental medi

Allergotoxicology: Research of Pollutant Influence on the Development of Allergic Reactions

Alergotoksikologija je znanstvenoistraživačko područje koje se bavi ispitivanjem utjecaja polutanata (onečišćivača zraka) na nastanak alergijskih reakcija i bolesti. Ispitivanja su prvobitno bila usmjerena na polutante vanjskih prostora, a u novije vrijeme sve više na polutante unutarnjih prostora u kojima ljudi provode većinu vremena. Polutanti po svojoj prirodi mogu biti krute, tekuće ili plinovite čestice, koje se razlikuju s obzirom na veličinu, sastav i izvor iz kojeg nastaju. S obzirom na izvor mogu biti biološkog i nebiološkog podrijetla. Polutanti koji su predmet suvremenih istraživanja s gledišta nastanka alergijskih bolesti su respirabilne krute čestice, ozon, dušični oksidi i bioaerosoli. Mehanizam djelovanja polutanata ovisi o veličini čestica, njihovoj topljivosti i mjestu ulaska u organizam. Dosadašnja ispitivanja su pokazala da različite čestice uvjetuju različite imunosne i neimunosne odgovore u organizmu. Interakcija polutanata i alergena može se zbivati izvan eksponirane osobe, tj. sa samim alergenom ili u eksponiranoj osobi na sluznicama i koži. Polutanti mogu biti nosioci alergena i mogu interferirati na različitim nivoima u nastanku alergijske reakcije. U ovom prikazu razma raju se dosadašnja saznanja o mehanizmima djelovanja polutanata na alergene, na imunosni sustav izloženih osoba na osnovi epidemioloških populacijskih istraživanja, kliničkih studija ekspozcije u kontroliranim uvjetima i eksperimentalnih testnih sistema in vivo i in vitro.Allergotoxicology studies the infl uence of pollutants on the development of allergic reactions and diseases. At the beginning, the research was focused on outdoor air pollutants, while recently it turns to the indoor environment, mainly because people this is where people spend most of their time. Air pollutants may be solid, soluble, or gaseous particles in nature, and they can differ in size, structure, and sources. Pollutants can be of biological or nonbiological origin. Currently interesting air pollutants include particulate matter, ozone, nitrogen oxides, and bioaerosols. The mechanisms of pollutant activity depend on the particle size, solubility, site of deposition, and specifi c chemical properties. Recent studies have shown that different pollutants provoke different immunological and nonimmunological responses in exposed persons. Interaction between air pollutants and allergens can take place outside the exposed person i.e. with allergen itself, or inside the organism on mucous membranes and skin. Pollutants may be the carriers of allergens and may exacerbate allergic reactions and diseases. This review presents recent views about the mechanisms of pollutant activity on allergens and immune system response in exposed persons, based on epidemiological population studies, clinical studies of exposure under controlled conditions, and experimental tests in vitro and in vivo

Low diversity of the gut microbiota in infants with atopic eczema

Background It is debated whether a low total diversity of the gut microbiota in early childhood is more important than an altered prevalence of particular bacterial species for the increasing incidence of allergic disease. The advent of powerful, cultivation-free molecular methods makes it possible to characterize the total microbiome down to the genus level in large cohorts. Objective We sought to assess microbial diversity and characterize the dominant bacteria in stool during the first year of life in relation to atopic eczema development. Methods Microbial diversity and composition were analyzed with barcoded 16S rDNA 454-pyrosequencing in stool samples at 1 week, 1 month, and 12 months of age in 20 infants with IgE-associated eczema and 20 infants without any allergic manifestation until 2 years of age (ClinicalTrials.gov ID NCT01285830). Results Infants with IgE-associated eczema had a lower diversity of the total microbiota at 1 month (P = .004) and a lower diversity of the bacterial phylum Bacteroidetes and the genus Bacteroides at 1 month (P = .02 and P = .01) and the phylum Proteobacteria at 12 months of age (P = .02). The microbiota was less uniform at 1 month than at 12 months of age, with a high interindividual variability. At 12 months, when the microbiota had stabilized, Proteobacteria, comprising gram-negative organisms, were more abundant in infants without allergic manifestation (Empirical Analysis of Digital Gene Expression in R [edgeR] test: P = .008, q = 0.02). Conclusion Low intestinal microbial diversity during the first month of life was associated with subsequent atopic eczema.Funding Agencies|BioGaia AB, Stockholm, Sweden||Ekhaga Foundation, the Heart and Lung foundation||Research Council for the South-East Sweden|F2000-106|Olle Engqvist Foundation||Swedish Asthma and Allergy Association||Swedish Research Council||University Hospital of Linkoping||Soderberg Foundation||Vardal Foundation for Health Care Science and Allergy Research, Sweden||BioGaia AB||</p