Recent inversion of the Tyrrhenian Basin

The Tyrrhenian Basin is a region created by Neogene extensional tectonics related to slab rollback of the east-southeast–migrating Apennine subduction system, commonly believed to be actively underthrusting the Calabrian arc. A compilation of >12,000 km of multichannel seismic profiles, much of them recently collected or reprocessed, provided closer scrutiny and the mapping of previously undetected large compressive structures along the Tyrrhenian margin. This new finding suggests that Tyrrhenian Basin extension recently ceased. The ongoing compressional reorganization of the basin indicates a change of the regional stress field in the area, confirming that slab rollback is no longer a driving mechanism for regional kinematics, now dominated by the Africa-Eurasia lithospheric collision

Laser-Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS): setting operating conditions and instrumental performance

The concentration of thirty nine geochemically relevant trace elements, from 7Li to 238U, was determined in standard silicate glasses (NIST610, NIST612, BCR-2) using the Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) instrumentation at the Department of Earth Sciences of the University of Cagliari (Italy). The device is a Quadrupole ICP-MS (Perkin Elmer Elan DRC-e) coupled with a 213 nm Nd:YAG laser probe (New Wave Research). This configuration allows rapid, high quality, in-situ trace elements analysis in glasses and minerals. The calibration strategy, achieved using synthetic multi-element glasses (NIST612), with 44Ca as internal standard, gives an analytical accuracy within 5% error level, providing a precision between 1% and 9%, at 40 µm of crater size for all elements. At a laser spot size of 40 m, the lower limit of detection (LLD) ranges between 0.001 and 1 ppm for all the elements; it increases by about one order of magnitude, without any significant fractionation among the different elements, for a laser spot size of 15 µm. Quality control of LA-ICP-MS analyses is routinely performed analysing a natural standard glass, the BCR-2, certified by the USGS, considered as unknown sample. Results indicate that the instrumentation capabilities are suitable for the geochemical characterisation of various materials of mineralogical, petrological, geological and environmental interest

Dynamics of ash-dominated eruptions at Vesuvius: the post-512 AD AS1a event

Recent stratigraphic studies at Vesuvius have revealed that, during the past 4,000 years, long lasting,moderate to low-intensity eruptions, associated with continuous or pulsating ash emission, have repeatedly occurred. The present work focuses on the AS1a eruption, the first of a series of ash-dominated explosive episodes which characterized the period between the two Subplinian eruptions of 472 AD and 1631 AD. The deposits of this eruption consist of an alternation of massive and thinly laminated ash layers and minor well sorted lapilli beds, reflecting the pulsatory injection into the atmosphere of variably concentrated ash-plumes alternating with Violent Strombolian stages. Despite its nearly constant chemical composition, the juvenile material shows variable external clast morphologies and groundmass textures, reflecting the fragmentation of a magma body with lateral and/or vertical gradients in both vesicularity and crystal content. Glass compositions and mineralogical assemblages indicate that the eruption was fed by rather homogeneous phonotephritic magma batches rising from a reservoir located at ~ 4 km (100 MPa) depth, with fluctuations between magma delivery and magma discharge. Using crystal size distribution (CSD) analyses of plagioclase and leucite microlites, we estimate that the transit time of the magma in the conduit was on the order of ~ 2 days, corresponding to an ascent rate of around 2× 10−2 ms−1. Accordingly, assuming a typical conduit diameter for this type of eruption, the minimum duration of the AS1a event is between about 1.5 and 6 years. Magma fragmentation occurred in an inertially driven regime that, in a magma with low viscosity and surface tension, can act also under conditions of slow ascent

Microbe-host interactions: structure and role of Gram-negative bacterial porins.

Gram negative bacteria have evolved many mechanisms of attaching to and invading host epithelial and immune cells. In particular, many outer membrane proteins (OMPs) are involved in this initial interaction between the pathogen and their host. The outer membrane (OM) of Gram-negative bacteria performs the crucial role of providing an extra layer of protection to the organism without compromising the exchange of material required for sustaining life. The OM, therefore, represents a sophisticated macromolecular assembly,whose complexity has yet to be fully elucidated.. This review will summarize the structural information available for porins, a class of OMP, and highlight their role in bacterial pathogenesis. The functional role of porins in microbe-host interactions during various bacterial infections has emerged only during the last few decades, and their interaction with a variety of host tissues for adhesion to and invasion of the cell and for evasion of host-defense mechanisms have placed bacterial porins at the forefront of research in bacterial pathogenesis. This review will discuss the role that porins play in activating immunological responses, in inducing signaling pathways and their influence on antibiotic resistance mechanisms that involve modifications of the properties of the OM lipid barrier

Antimicrobial activity of bovine lactoferrin-derived peptides

Antimicrobial peptides, such as bovine lactoferrin (bLF), are produced by a wide variety of organisms. AMPs represent a first line defence against invading microbes and are found in large quantity in several secretory fluids [1] . They are relatively short, amphiphilic and positively charged. bLF is an 80- kDa iron-binding, multifunctional cationic glycoprotein of the transferrin family. This protein is active against a widespread range of microbiological organisms: bacteria, viruses, fungi and parasites [2,3,4]. In order to obtain novel active peptides from bLF, several approaches have been used. Two novel active peptides have been identified in our study. In agreement with the not disclosure agreement for the pending patent N°102015000044047*, we are not allowed to report the sequences in the abstract. These peptides, named respectively KFp and LKp, were synthesized using the standard solid-phase- 9-fluorenylmethoxycarbonyl (Fmoc) method. Antibacterial activity of KFp and LKp was analyzed by minimal inhibitory concentration (MIC) using the broth microdilution method outlined by the Clinical and Laboratory StandardsInstitute (CLSI) on two bacteria strains: Escherichia coli ATCC 11229 and Staphylococcus aureus ATCC 6538. Likewise, the antiviral activity was performed on HSV-1using a co-treatment assay. Moreover, their cytotoxicity activity was evaluated by the MTT assay.According to the study conducted, these novel peptides show a marked broad-spectrum antimicrobial and antiviral activity with a low toxicity. This can be a favorable prerequisite for the developing and for the use of these peptides in vivo, as additional therapeutic agents and/or as alternative to the conventional antibiotics