Urinary 1H NMR metabolomics profile of Italian citizens exposed to background levels of arsenic: a (pre)cautionary tale.

Objectives: Arsenic is a toxic metal ubiquitous in the environment and in daily life items. Long-term arsenic exposure is associated with severe adverse health effects involving various target organs. It would be useful to investigate the existence of metabolic alterations associated with lifestyle and/or with the environment. For this purpose, we studied the correlation between urinary arsenic levels and urinary proton nuclear magnetic resonance spectroscopy (1H NMR) metabolomics profiles in a non-occupationally nor environmentally arsenic exposed general population.Methods: Urine samples were collected from 86 healthy subjects. Total and non-alimentary urinary arsenic (U-naAs) levels, namely the sum of arsenite, arsenate, monomethylarsonate and dimethylarsinate, were measured and 1H NMR analysis was performed. Orthogonal Projection to Latent Structures was applied to explore the correlation between the metabolomics profiles and U-naAs levels.Results: Despite the extremely low U-naAs levels (mean value = 6.13 ± 3.17 µg/g creatinine) of our studied population a urinary metabolomics profile related to arsenic was identified.Conclusion: The identified profile could represent a fingerprint of early arsenic biological effect and could be used in further studies as an indicator of susceptibility, also in subjects exposed to a low arsenic dose, with implications in occupational health, toxicology, and public health.

Metabolomic patterns associated to QTc interval in shiftworkers: an explorative analysis.

OBJECTIVES: (1)H NMR-metabolomic approach was used to investigate QTc interval correlation with plasma metabolic profiles in shiftworkers. METHODS: Socio-demographic data, electrocardiographic QTc interval and plasma metabolic profiles from 32 male shiftworkers, were correlated by multivariate regression analysis. RESULTS: We found a positive correlation between QTc interval values, body mass index, glycemia and lactate level and a negative correlation between QTc interval and both pyroglutamate and 3-hydroxybutyrate plasma level. CONCLUSIONS: Our analysis provides evidence of the association between clinical, metabolic profiles and QTc interval values. This could be used to identify markers of early effects and/or susceptibility in shiftworkers.

Absorption F-sum rule for the exciton binding energy in methylammonium lead halide perovskites.

Advances of optoelectronic devices based on methylammonium lead halide perovskites depend on understanding the role of excitons, whether it is marginal as in inorganic semiconductors, or crucial, like in organics. However, a consensus on the exciton binding energy and its temperature dependence is still lacking, even for widely studied methylammonium lead iodide and bromide materials (MAPbI3, MAPbBr3). Here we determine the exciton binding energy based on an f-sum rule for integrated UV-vis absorption spectra, circumventing the pitfalls of least-squares fitting procedures. In the temperature range 80-300 K, we find that the exciton binding energy in MAPbBr3 is EB = (60 ± 3) meV, independent of temperature; for MAPbI3, in the orthorhombic phase (below 140 K) EB = (34 ± 3) meV, while in the tetragonal phase the binding energy softens to 29 meV at 170 K and stays constant up to 300 K. Implications of binding energy values on solar cell and LED workings are discussed.

Correlated electron-hole plasma in organometal perovskites.

Organic-inorganic perovskites are a class of solution-processed semiconductors holding promise for the realization of low-cost efficient solar cells and on-chip lasers. Despite the recent attention they have attracted, fundamental aspects of the photophysics underlying device operation still remain elusive. Here we use photoluminescence and transmission spectroscopy to show that photoexcitations give rise to a conducting plasma of unbound but Coulomb-correlated electron-hole pairs at all excitations of interest for light-energy conversion and stimulated optical amplification. The conductive nature of the photoexcited plasma has crucial consequences for perovskite-based devices: in solar cells, it ensures efficient charge separation and ambipolar transport while, concerning lasing, it provides a low threshold for light amplification and justifies a favourable outlook for the demonstration of an electrically driven laser. We find a significant trap density, whose cross-section for carrier capture is however low, yielding a minor impact on device performance.

Haplotype affinities resolve a major component of goat (Capra hircus) MtDNA D-loop diversity and reveal specific features of the Sardinian stock.

Goat mtDNA haplogroup A is a poorly resolved lineage absorbing most of the overall diversity and is found in locations as distant as Eastern Asia and Southern Africa. Its phylogenetic dissection would cast light on an important portion of the spread of goat breeding. The aims of this work were 1) to provide an operational definition of meaningful mtDNA units within haplogroup A, 2) to investigate the mechanisms underlying the maintenance of diversity by considering the modes of selection operated by breeders and 3) to identify the peculiarities of Sardinian mtDNA types. We sequenced the mtDNA D-loop in a large sample of animals (1,591) which represents a non-trivial quota of the entire goat population of Sardinia. We found that Sardinia mirrors a large quota of mtDNA diversity of Western Eurasia in the number of variable sites, their mutational pattern and allele frequency. By using bayesian analysis, a distance-based tree and a network analysis, we recognized demographically coherent groups of sequences identified by particular subsets of the variable positions. The results showed that this assignment system could be reproduced in other studies, capturing the greatest part of haplotype diversity.We identified haplotype groups overrepresented in Sardinian goats as a result of founder effects. We found that breeders maintain diversity of matrilines most likely through equalization of the reproductive potential. Moreover, the relevant amount of inter-farm mtDNA diversity found does not increase proportionally with distance. Our results illustrate the effects of breeding practices on the composition of maternal gene pool and identify mtDNA types that may be considered in projects aimed at retrieving the maternal component of the oldest breeds of Sardinia.