The Role of Microbiota in Cardiovascular Risk: Focus on Trimethylamine Oxide

The extensive collection of bacteria cohabiting within the host collaborates with human functions and metabolisms in both health and disease. The fine equilibrium of commensals is tightly controlled and an imbalance (“dysbiosis”) in the gut microbiota can play different roles in human disease. The development of new genome sequencing techniques has allowed a better understanding of the role of human gut microbiota. This led to the identification of numerous metabolites produced in the gut, which have been suggested to play a role in human disease. Among these, trimethylamine oxide (TMAO) appears to be of particular importance as a risk factor and potentially as a causative agent of various pathologies, most remarkably cardiovascular and disease and other associated conditions. Mechanistic links are yet to be established, however, increased levels of TMAO have been shown to augment the risk of developing renal failure, metabolic syndrome, diabetes mellitus, heart failure, hypertension, atherosclerosis, and dyslipidemia ultimately leading to increased risk of serious cardiovascular events. This article reviews the potential impact of TMAO in human cardiovascular disease

Transfer of spectral weight across the gap of Sr2IrO4 induced by La doping

We study with Angle Resolved PhotoElectron Spectroscopy (ARPES) the evolution of the electronic structure of Sr2IrO4, when holes or electrons are introduced, through Rh or La substitutions. At low dopings, the added carriers occupy the first available states, at bottom or top of the gap, revealing an anisotropic gap of 0.7eV in good agreement with STM measurements. At further doping, we observe a reduction of the gap and a transfer of spectral weight across the gap, although the quasiparticle weight remains very small. We discuss the origin of the in-gap spectral weight as a local distribution of gap values

Quasiparticles dynamics in high-temperature superconductors far from equilibrium: an indication of pairing amplitude without phase coherence

We perform time resolved photoelectron spectroscopy measurements of optimally doped \tn{Bi}_2\tn{Sr}_2\tn{CaCu}_2\tn{O}_{8+\delta} (Bi-2212) and \tn{Bi}_2\tn{Sr}_{2-x}\tn{La}_{x}\tn{Cu}\tn{O}_{6+\delta} (Bi-2201). The electrons dynamics show that inelastic scattering by nodal quasiparticles decreases when the temperature is lowered below the critical value of the superconducting phase transition. This drop of electronic dissipation is astonishingly robust and survives to photoexcitation densities much larger than the value sustained by long-range superconductivity. The unconventional behaviour of quasiparticle scattering is ascribed to superconducting correlations extending on a length scale comparable to the inelastic path. Our measurements indicate that strongly driven superconductors enter in a regime without phase coherence but finite pairing amplitude. The latter vanishes near to the critical temperature and has no evident link with the pseudogap observed by Angle Resolved Photoelectron Spectroscopy (ARPES).Comment: 7 pages, 5 Figure

Along strike preorogenic thickness variation and onlapping geometries control on thrust wedge evolution: insight from sandbox analogue modelling

Abstract: Thickness variation of sedimentary sequences is largely viewed as a controlling factor on the evolution of orogenic wedges; among the different structural and stratigraphic features generating thickness variation, we focused our analysis on the onlapping geometries, using laboratory sandbox experiments. The aim was trying to describe how a common sedimentary configuration could influence thrusts geometry and mode of accretion. Model results showed that onlapping geometries in pretectonic sediments cause a great complexity, dominated by curvilinear thrusts, back thrust and out-ofsequence thrusts. They also influence mode of accretion, generating diachronous thrusting along strike, reactivation and under-thrusting alternating to simple piggy-back sequence. Our modeling results are compared with natural examples from the Apennines, the southern Pyrenees, the Pindos (Greece) and the West Spitsbergen (Greenland) fold and thrust belts, among many others, where strain localization and diachronic thrusting affecting thrust propagation in correspondence to complex geometries both in the pre-orogenic stratigraphy and in the upper crust

Ultrafast far-infrared optics of carbon nanotubes

The optical properties of single-wall carbon nanotube sheets in the far-infrared (FIR) spectral range from few THz to several tens of THz have been investigated with terahertz spectroscopy both with static measurements elucidating the absorption mechanism in the FIR and with time-resolved experiments yielding information on the charge carrier dynamics after optical excitation of the nanotubes. We observe an overall depletion of the dominating broad absorption peak at around 4THz when the nanotubes are excited by a short visible laser pulse. This finding excludes particle-plasmon resonances as absorption mechanism and instead shows that interband transitions in tubes with an energy gap of ~10meV govern the far-infrared conductivity. A simple model based on an ensemble of two-level systems naturally explains the weak temperature dependence of the far-infrared conductivity by the tube-to-tube variation of the chemical potential. Furthermore, the time-resolved measurements do not show any evidence of a distinct free-carrier response which is attributed to the photogeneration of strongly bound excitons in the tubes with large energy gaps. The rapid decay of a featureless background with pronounced dichroism is associated with the increased absorption of spatially localized charge carriers before thermalization is completed

A MULTI-SENSOR APPROACH TO SURVEY COMPLEX ARCHITECTURES SUPPORTED BY MULTI-CAMERA PHOTOGRAMMETRY

Point clouds are nowadays a standard format of three-dimensional data. Various survey techniques are available, differing in characteristics, mode of use, and target applications, nevertheless producing point clouds that are similar, comparable, and combinable. According to recent literature, combining data from multiple sensors is an established practice for large surveying projects, particularly in Cultural Heritage, where the geometric complexity of buildings encourages the employment of many sensors. This paper presents a multi-sensor approach to surveying complex architectural spaces. The case study is the Cathedral of Aosta (AO) in Italy, which is interested in a conservation project that requires investigating the two bell towers of the cathedral. The survey aimed to produce a point cloud of 5 mm resolution and 1–2 cm accuracy compatible with the 1:50 scale of representation. The following survey techniques were employed: (i) laser scanning, (ii) terrestrial photogrammetry, (iii) UAV photogrammetry, and (iv) multi-camera fisheye photogrammetry. The distinctive feature of our approach lies in the multi-camera survey, conducted using a prototype composed of five fisheye cameras. The paper describes the data acquisition phase conducted with the different techniques, the mutual verification of the data performed by cross-sections check, the segmentation, and the final assembly of the various portions until a complete point cloud with homogeneous characteristics is obtained. All the data were then collected in a web platform (FlyVast) enriched with data and info made available to the professional to plan future interventions

Temperature dependence of ultrafast phonon dynamics in graphite

Nonequilibrium optical phonons are generated in graphite following the excitation of electron-hole pairs with a femtosecond laser pulse. Their energy relaxation is probed by means of terahertz pulses. We find that the hot-phonon lifetime increases by a factor of 2 when the sample temperature decreases from 300 to 5 K. These results suggest that the energy relaxation in graphite at room temperature and above is dominated by the anharmonic decay of hot A′1phonons at the K point into acoustic phonons with energies of about 10 meV