Laser ablation coupled to mass quadrupole spectrometry for analysis in the cultural heritage

A Nd:YAg laser operating at 1064 nm, 150 mJ, 3 ns pulse duration, 1-10 Hz repetition rate and 109 W/cm2 intensity is employed to irradiate ancient metallic and ceramic samples in high vacuum. A mass quadrupole spectrometer (MQS), operating between 1-300 amu with sensitivity better than 0.1 ppm, analyzes elements and compounds. Repetitive laser ablation removes in controlled manner the first surface layers of the irradiated samples so that the irradiation time can be correlated to the layer depth. MQS can be fixed to peculiar masses so that during the laser irradiation the mass yields can be plotted as a function of the sample depth. The technique permits to give the depth profiles of elements, chemical compounds and isotopes characterizing the composition of the analyzed samples. The analysis of ancient coins based on bronze and silver alloys and of old vitrified colored ceramics has been investigated to identify peculiar elements of the colored layers. Particularly, the lead isotopic ratios 208Pb/207Pb and 206Pb/207Pb were measured in bronze coins. Measurements were compared with the database of lead isotopic ratios in lead minerals extracted from old mines in the Mediterranean basin. In some cases, of special interest for Archeologists, the comparison has indicated that the lead employed for the coin production could have been extracted from mines of particular geographic sites. © Published under licence by IOP Publishing Ltd

Laser-generated plasmas by graphene nanoplatelets embedded into polyethylene

AbstractGraphene micrometric particles have been embedded into polyethylene at different concentrations by using chemical–physical processes. The synthesized material was characterized in terms of mechanical and optical properties, and Raman spectroscopy. Obtained targets were irradiated by using a Nd:YAG laser at intensities of the order of 1010 W/cm2 to generate non-equilibrium plasma expanding in vacuum. The laser–matter interaction produces charge separation effects with consequent acceleration of protons and carbon ions. Plasma was characterized using time-of-flight measurements of the accelerated ions. Applications of the produced targets in order to generate carbon and proton ion beams from laser-generated plasma are presented and discussed

Monitoring System of Eastern Sicily (Italy) devised by a specialist team (UFSO) at the INGV- Catania Section, Italy.

Eastern Sicily in Italy is well-known as a high seismic and volcanic risk area. From a monitoring point of view, a team/unit of people has been created (UFSO) with the task of managing all the activities connected to the faultless operation of the Working Room that is the strategic centre during periods of routine operations or in the case of emergency. Among the primary activities of monitoring and surveillance, the management of the video camera network located on the main Sicilian active volcanoes represents a major goal. This task is achieved by means of permanent, visible and infrared cameras together with similar mobile systems, in order to observe each phenomenon related to the volcanic activity. The expert staff can therefore make decisions, in real time, from useful information in order to understand the phenomena in action. With the aim of maximizing the results and performance of all the networks, the UFSO is attentive to the planning and realization of hardware and software systems that are always available in the mobile van unit. In this context, the staff actively participates in national and European research projects dealing with the development and use of new systems with high technological content. Another aspect of the work, moreover, is represented by the development of supervisory control software, namely software providing automatic control of the working systems. Such algorithms allow to immediately and remotely signal to the duty-personnel states of alert of several modules, indicating, when possible, the probable failure causes

Multicharged Carbon Ion Generation from Laser Plasma

Carbon ions generated by ablation of a carbon target using an Nd:YAG laser pulse (wavelength λ = 1064 nm, pulse width τ = 7 ns, and laser fluence of 10-110 J cm-2) are characterized. Time-of-flight analyzer, a three-mesh retarding field analyzer, and an electrostatic ion energy analyzer are used to study the charge and energy of carbon ions generated by laser ablation. The dependencies of the ion signal on the laser fluence, laser focal point position relative to target surface, and the acceleration voltage are described. Up to C4+ ions are observed. When no acceleration voltage is applied between the carbon target and a grounded mesh in front of the target, ion energies up to ∼400 eV/charge are observed. The time-of-flight signal is analyzed for different retarding field voltages in order to obtain the ion kinetic energy distribution. The ablation and Coulomb energies developed in the laser plasma are obtained from deconvolution of the ion time-of-flight signal. Deconvolution of the time-of-flight ion signal to resolve the contribution of each ion charge is accomplished using data from a retarding field analysis combined with the time-of-flight signal. The ion energy and charge state increase with the laser fluence. The position of the laser focal spot affects the ion generation, with focusing ∼1.9 mm in front of the target surface yielding maximum ions. When an external electric field is applied in an ion drift region between the target and a grounded mesh parallel to the target, fast ions are extracted and separated, in time, due to increased acceleration with charge state. Published by AIP Publishing. [http://dx.doi.org/10.1063/1.4966987

A protective role for autophagy in vitiligo

A growing number of studies supports the existence of a dynamic interplay between energetic metabolism and autophagy, whose induction represents an adaptive response against several stress conditions. Autophagy is an evolutionarily conserved and a highly orchestrated catabolic recycling process that guarantees cellular homeostasis. To date, the exact role of autophagy in vitiligo pathogenesis is still not clear. Here, we provide the first evidence that autophagy occurs in melanocytes and fibroblasts from non-lesional skin of vitiligo patients, as a result of metabolic surveillance response. More precisely, this study is the first to reveal that induction of autophagy exerts a protective role against the intrinsic metabolic stress and attempts to antagonize degenerative processes in normal appearing vitiligo skin, where melanocytes and fibroblasts are already prone to premature senescence

A stable, power scaling, graphene-mode-locked all-fiber oscillator

This is the final version. Available from AIP Publishing via the DOI in this record.We report power tunability in a fiber laser mode-locked with a solution-processed filtered graphene film on a fiber connector. 370 fs pulses are generated with output power continuously tunable from 4 up to 52 mW. This is a simple, low-cost, compact, portable, all-fiber ultrafast source for applications requiring environmentally stable, portable sources, such as imaging.European Research Council (ERC)Engineering and Physical Sciences Research Council (EPSRC)Emmanuel College, CambridgeIsaac Newton Trust, Trinity College Cambridg

A stable, power scaling, graphene-mode-locked all-fiber oscillator

We report power tunability in a fiber laser mode-locked with a solution-processed filtered graphene film on a fiber connector. ∼370 fs pulses are generated with output power continuously tunable from ∼4 up to ∼52 mW. This is a simple, low-cost, compact, portable, all-fiber ultrafast source for applications requiring environmentally stable, portable sources, such as imaging.</jats:p