Microstructure and chemical composition of Roman orichalcum coins emitted after the monetary reform of Augustus (23 B.C.)

A collection of ancient Roman orichalcum coins, i.e., a copper-zinc alloy, minted under the reigns from Caesar to Domitianus, have been characterised using scanning electron microscopy (SEM-EDS) and electron microprobe analysis (EMPA). We studied, for the first time, coins emitted by Romans after the reforms of Augustus (23 B.C.) and Nero (63-64 A.D). These coins, consisting of asses, sestertii, dupondii and semisses, were analysed using non- and invasive analyses, aiming to explore microstructure, corrosive process and to acquire quantitative chemical analysis. The results revealed that the coins are characterized by porous external layers, which are affected by dezincification and decuprification processes. As pictured by the X-ray maps, the elemental distribution of Cu and Zn shows patterns of depletion that in some cases penetrate in deep up to 1 mm. The composition of the un-corroded nucleus is a Cu-Zn alloy containing up to 30% of Zn, typical of coins produced via cementation process

Epigenetic factors and mitochondrial biology in yeast: A new paradigm for the study of cancer metabolism?

Bidirectional cross-talk between nuclear and mitochondrial DNA is fundamental for cell homeostasis. Epigenetic mechanisms regulate the inter-organelle communication between nucleus and mitochondria. Recent research highlights not only the retrograde activation of nuclear gene transcription in case of mitochondria dysfunction, but also the role of post-translational modifications of mitochondrial proteins in respiratory metabolism. Here we discuss some aspects and novel findings in Saccharomyces cerevisiae. In yeast, KAT-Gcn5 and DUB-Ubp8 have a role in respiration and are localized, as single proteins, into mitochondria. These findings, beside the canonical and widely known nuclear activity of SAGA complex in chromatin regulation, provide novel clues on promising aspects linking evolutionary conserved epigenetic factors to the re-programmed metabolism of cancer cells

Site effects at the Campi Flegrei,preliminary results

The Campi Flegrei caldera is a complex structure with a high population density, located west of the city of Naples. In addition of being an active volcano it is characterized by a high seismic hazard due to both Appennines regional earthquakes and to local earthquakes occurring during the bradyseismic crises. These unrest phenomena are characterized by slow ground vertical movements, particularly active in the central part of the caldera, and by a high number of low-magnitude earthquakes. In this context, the determination of the site transfer functions of the area has a strong relevance for the Civil Defense aimed to determine the hazard of the area. We have calculated the site transfer function with different techniques (H/V and Generalized Inversion technique) and have collected data on the local geology with the aim of correlating the site transfer functions with lithology and topography. This analysis has been performed on three areas: the Astroni crater, the Camaldoli hill and the Agnano plain. A future development will be to extend this analysis to the whole Campi Flegrei area

Somma Vesuvius: the Volcano and the Observatory

The present guidebook was prepared for the fieldtrip during the Kick off meeting of the project titled “Strategies and tools for Real Time Earthquake RisK ReducTion” (REAKT). It reports information on the geology of the Somma-Vesuvius volcanic area and illustrates the sites visited during the field excursion. The guide mostly benefited of contributions coming from some previous guidebooks (Cioni et al., 1995; Orsi et al., 1998); it also includes some interesting results available in the main and most recent literature. The fieldtrip will be devoted to illustrating i) the major morphological and structural features of the Somma-Vesuvius volcano, and ii) the deposits of the eruptions and their impact on the territory. The trip will end with the tour of the Osservatorio Vesuviano edifice that preserves the memory of the oldest volcanological observatory in the world and hosts a museum and two scientific exibitions

Role of phase nanosegregation in the photoluminescence spectra of halide perovskites

The study of MAPbI3 phase transitions based on temperature-dependent optical spectroscopy has recently gained a huge attention. Photoluminescence (PL) investigations of the tetragonal-orthorhombic transition suggest that tetragonal nanodomains are present below the transition temperature and signatures associated with tetragonal segregations are observed. We have studied the impact of phase nanosegregation across the orthorhombic-tetragonal phase transition of MAPbI3 on the system's properties employing a tight binding (TB) approach. The particle swarm optimization has been used to obtain a consistent set of TB parameters, where the target properties of the system have been derived by first-principles calculations. The theoretical results have been compared with the measured PL spectra for a temperature range going from 10 to 100 K. Our model effectively captures the carriers' localization phenomenon induced by the presence of residual tetragonal nanodomains and demonstrates that the assumption of phase nanosegregation can explain the low-energy features in the PL spectra of MAPbI3

Distal tephra from Campanian eruptions in early Late Holocene fills of the Agro Pontino graben and Fondi basin (Southern Lazio, Italy)

Following on the discovery (in 2011) of a layer of distal tephra from the Pomici di Avellino eruption (Somma-Vesuvius, EU5) in the Agro Pontino (southern Lazio, Italy), further detailed study of the Holocene sediment archives in this graben and in the nearby Fondi coastal basin showed that distal tephra from this EU5 eruption occurs as a rather continuous, conspicuous layer. Two other, less conspicuous tephra layers were found, identified as the earlier Astroni 6 eruption from the Campi Flegrei (Fondi basin) and the later AP2 eruption of the Somma-Vesuvius (Agro Pontino). The identification of the distal tephra layers rests upon a combination of criteria, including stratigraphy, macro characteristics, mineralogy, geochemical data on glass composition, Sr-isotopic ratios, and the known tephrochronology for the period concerned, i.e. between c. 2500 and 1000 BCE. 14C datings serve to constrain their age. No significant spatial variation in the characteristics of the main tephra layer (EU5) was observed, other than distinct fining with increasing distance from the vent. Based on a detailed palaeogeographical reconstruction, the occurrence and preservation of these tephra are explained by the local environmental conditions governing their preservation during this time span (the Central Italian Bronze Age), and by the later evolution of the area. The observations underpin that multiple corings are needed to fully assess whether sedimentary hiatuses exist in palaeorecords, based on cores from sediment archives. Lastly, our study shows that hazard evaluations for future eruptions by Campanian volcanoes should pay more attention to their potential impacts on distal areas

Elucidation of role of graphene in catalytic designs for electroreduction of oxygen

Graphene is, in principle, a promising material for consideration as component (support, active site) of electrocatalytic materials, particularly with respect to reduction of oxygen, an electrode reaction of importance to low-temperature fuel cell technology. Different concepts of utilization, including nanostructuring, doping, admixing, preconditioning, modification or functionalization of various graphene-based systems for catalytic electroreduction of oxygen are elucidated, as well as important strategies to enhance the systems' overall activity and stability are discussed