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Electronic nicotine delivery systems such as e-cigarettes are commonly felt to be harmless devices when compared to traditional cigarettes. However, an increasing number of studies support the biological plausibility for the potential detrimental effects of vaping on the respiratory mucosa. To date, few human studies have been carried out on adult vapers showing a reduction in lung function testing, especially in those with asthma, whereas the effects of vaping on children and adolescents have not been elucidated so far.Several cross-sectional, national, population-based studies on large groups of adolescents have been carried out showing an association between vape exposure and self-reported asthma diagnosis and/or respiratory symptoms in this age group. The effects of second and third-hand exposure together with those of active and passive exposure in pregnancy, are almost completely unknown.This review outlines recent data on the potential effects of vaping on asthma, focusing on vape composition, reported effects on the respiratory mucosa, available data in adolescents, and reasons behind the current vaping epidemic. The evidence so far available both in animals and humans suggests that vaping is not harmless, and its exposure should be limited in children and adolescents, especially when affected by asthma.

Ground-based synthetic aperture radars (GBSAR) are popular instruments widely used for the monitoring of infrastructures. One of the main problems of ground-based interferometric radars is the elevation ambiguity. Multiple-input multiple-output (MIMO) arrays could solve this problem. This work proposes a study on possible MIMO configurations to achieve elevation resolution in ground-based radar measurements. Specifically, two array configurations are compared: a random sparse array suitable for the compressive sensing technique, and a non-uniform array. The two solutions are compared by means of simulations and experimental tests. An ad hoc system has been developed to jointly test the two configurations, and results obtained in a controlled and real urban scenario are shown. It is found that both systems are able to solve elevation ambiguity. The non-uniform array seems to achieve good performance in a general scenario, while the CS processing can outperform the other only after optimization, depending on the specific scenario and application.

Since the 1950s, radar sensors have been widely used for the monitoring of the earth’s surface. The current radars for remote sensing can be divided into two main categories: Space/aerial-borne and ground-based systems. The unmanned aerial system (UAS) could bridge the gap between these two technologies. Indeed, UAS-borne radars can perform long scans (up to 100/200 m) in a brief time (a few minutes). From the 2010s, the interest in UAS-borne radars has increased in the research community, and it has led to the development of some commercial equipment and more than 150 papers. This review aims to present a study on the state-of-the-art of UAS-borne radars and to outline the future potential of this technology. In this work, the scientific literature was categorized in terms of application, purpose of the paper, radar technology, and type of UAS. In addition, a brief review of the main national UAS regulations is presented. The review on the technological state-of-the-art shows that there is currently no standard in terms of radar technology, and that the multi-helicopter could be the most used UAS in the near future. Moreover, the UAS-borne radar can be used for several remote sensing applications: From landmine detection to smart agriculture, and from archeological survey to research and rescue applications. Finally, the UAS-borne radar appears to be a mature technology, which is almost ready for industrialization. The main developmental limit may be found in the flight regulation, which does not allow for many operations and imposes strict limits on the payload weight.

Interferometric radars are widely used for static and dynamic monitoring of large structures such as bridges, culverts, wind turbine towers, chimneys, masonry towers, stay cables, buildings, and monuments. Most of these radars operate in Ku-band (17 GHz). Nevertheless, a higher operative frequency could allow the design of smaller, lighter, and faster equipment. In this paper, a fast MIMO-GBSAR (Multiple-Input Multiple-Output Ground-Based Synthetic Aperture Radar) operating in W-band (77 GHz) has been proposed. The radar can complete a scan in less than 8 s. Furthermore, as its overall dimension is smaller than 230 mm, it can be easily fixed to the head of a camera tripod, which makes its deployment in the field very easy, even by a single operator. The performance of this radar was tested in a controlled environment and in a realistic case study.

This paper reports the results of a ground penetrating radar (GPR) survey of the ground-floor of Academia Gallery (Florence, Italy) where the Michelangelo’s David is exhibited to the public. The equipment used was a step-frequency GPR operating in the 100 MHz-1 GHz band, named ORFEUS. The survey covered an area of 13 m × 7.3 m, and the scans were performed along two orthogonal directions. Acquisitions in the same direction were separated by 0.25 m from each other. The GPR was able to confirm the underground structure, as it can be deducted by planimetry and historical documentation. In particular, the radar clearly detected the air-conditioning ducts under the floor and an approximately circular foundation below the basement of the statue.

(1) Background: Children with chronic medical conditions may be at increased risk for severe complications related to vaccine-preventable infections. Therefore, additional booster doses or supplementary vaccines are recommended, over and above the routine immunization schedule for healthy children. The aim of this study was to investigate attitude, knowledge, and practices toward additional vaccinations for children affected by chronic conditions among pediatricians and parents. (2) Methods: This study is based on two surveys: (i) a national cross-sectional survey, targeting pediatrician working in hospitals or in the primary health sector, (ii) a local cross-sectional survey, targeting parents of children with a previous diagnosis of chronic disease. (3) Results: Despite the fact that most of the health professionals and parents interviewed had an overall positive vaccine attitude, most pediatricians did not show an adequate knowledge of additional vaccinations for children affected by chronic diseases. Moreover, the coverage of additional recommended vaccinations in chronic pediatric patients was low. (4) Conclusions: This research highlighted important existing challenges hampering optimal vaccination coverage among pediatric chronic patients, including knowledge gaps on tailored vaccination schedules among pediatricians and organizational issues. The ongoing review of the Italian national immunization plan is a not-to-be-missed-opportunity to include evidence-based, detailed, and comprehensive recommendations on vaccinations for children affected by chronic conditions.

In recent years, interferometric radar has been extensively used as a sensor for static and dynamic monitoring of bridges. Generally speaking, a radar can only detect displacement components along the view direction. As the movement of a real bridge or of a large structure can be rather complex, this limitation can be a significant drawback in engineering practice. In order to overcome this limitation, in this article, a multi-monostatic radar for retrieving the displacement vector is proposed. It is basically a multiple input, multiple output (MIMO) interferometric radar, equipped with a transponder that consists of a pair of antennae, with relative amplifiers, connected to the radar with a radiofrequency (RF) cable. This arrangement allows for the simultaneous detection of two independent displacement components. The radar was successfully tested both in a controlled environment and in the field on a real bridge crossing the Arno river in Florence, Italy.

In recent years, interferometric radars have been extensively used as sensors for static and dynamic monitoring of bridges. Generally speaking, a radar can only detect the displacement component along its view direction. As the movement of a real bridge or a large structure can be rather complex, this limitation can be a significant drawback in engineering practice. In order toovercome this limitation, in this article, a multi-monostatic interferometric radar with radio link is proposed. This radar is able to detect a second component of displacement using a transponder. The transponder is connected to the radar through a radio link. The radio link allows the installation of the transponder far away from the radar, and even in the opposite direction. The equipment is based on a MIMO radar, two transceivers for the radio link, and a transponder. The transceivers and the transponder are essentially two antennas and an amplifier system. The equipment is experimentally tested in controlled scenarios and in the case study of Indiano Bridge, Florence, Italy.

The transition from corrosion product formation to protective passivation has been studied for several Al-Cr-Fe Complex Metallic Alloys (CMA) phases during long immersion time (269 days) in 0.01 mol L−1 HCl + 1 M NaCl at pH 2.0, using ICPMS (Inductively Coupled Plasma Mass Spectrometry) and UV- Visible spectroscopy analysis. The different dissolution mechanisms of the investigated phases could be identified by the formation of either Fe(II) or Fe(III) species. In the case of the actively corroding 12.5%at Cr containing phase, Fe(II) complexes were detected in solution, whereas for the passive 27.2%at Cr gamma phase, Fe(III) species were mainly present due to the passive dissolution of the nm-thick protective oxyhydroxide film. Subsequent Raman characterisations of the surface indicated the presence of a Fe3O4 -type layer on the corroding low Cr containing phases surface which is in agreement with the formation of a Fe(II)/Fe(III) mixed oxide. Speciation simulations allowed predicting Fe(III)-Cl complexes as stable species in the studied environments and related precipitation phenomena controlling the pH evolution. These results can further be used to characterise the active to passive corrosion transition occurring also in different Fe,Cr- containing alloys (like stainless steels) in acidic domain.

The formation, chemical composition and especially electrochemical reactivity of the passive oxide formed on the Al64.2Cr27.2Fe8.1 (at. %) and Al66.9Cu11.6Fe11.6Cr10.6 (at. %) complex metallic alloys (CMAs) were investigated in borate buffer electrolyte of pH8.4 and 0.1 M Na2SO4 electrolyte of pH 12. Open Circuit Potential evolution, potentiodynamic and potentiostatic anodic polarisation as well as electrochemical impedance measurements revealed high stability of the investigated materials in the alkaline domain relevant to cathodic areas. The high stability of these phases is attributed to the presence of a passive oxyhydroxide layer consisting of thin chromium oxyhydroxide as outermost layer and an inner aluminium oxyhydroxide layer close to the metal/oxide interface as found by XPS. The semiconducting properties characterised by means of photoelectrochemistry reveal further that the bandgap of the passive oxide on the CMAs corresponds to a less hydrated situation (closer to alumina) compared to the one grown on pure Al, thus supporting the higher stability of the CMAs phases.

High-angle annular dark-field scanning transmission electron microscopy (HAADF STEM) has been performed along the low-index zone axes of the o-Al4(Cr,Fe) complex metallic alloy to obtain a real-space representation of the crystal structure and to elucidate the material's inherent structural disorder. By comparing experiments with multislice STEM simulations, the model previously suggested by X-ray diffraction is further refined to provide a new set of positions and occupancies for the transition metal atoms.Pmnbis suggested as the new space group for the o-Al4(Cr,Fe) phase. A nonperiodic layer-type modulation, averaged out in bulk diffraction methods, is detected, corroborating the need for complementing bulk diffraction analysis with real-space imaging to derive the true crystal structure of Al4(Cr,Fe).

Thermoelectric half-Heusler compounds with the nominal composition (Ti0.33Zr0.33Hf0.33)NiSn were synthesized and exposed to operating conditions, i.e., elevated temperatures and oxidizing atmosphere. As-prepared samples were found to be a stable multiphase system consisting of Ti- and (Zr,Hf)-rich phases with half-Heusler structure. The influence of an oxidizing atmosphere at elevated temperatures on the sample was studied in- and ex situ by optical and electron microscopy and thermal analysis. Exposure to air resulted in surface oxidation starting at T = 545 K. During a defined heat treatment the Ti-rich phase decomposed while the (Zr,Hf)-rich phase was stable. In situ Atomic Force Microscopy and Scanning Kelvin Probe Force Microscopy experiments confirmed that interfaces, especially grain boundaries, are most prone to phase decomposition.

Al-Cr-Fe complex metallic alloys are new intermetallic phases with low surface energy, low friction, and high corrosion resistance down to very low pH values (0-2). Flow microcapillary plasma mass spectrometry under potentiostatic control was used to characterize the dynamic aspect of passivation of an Al-Cr-Fe gamma phase in acidic electrolytes, allowing a better insight on the parameters inducing chemical stability at the oxyhydroxide-solution interface. In sulfuric acid pH 0, low element dissolution rates (in the mu g cm(-2) range after 60 min) evidenced the passive state of the Al-Cr-Fe gamma phase with a preferential over-stoichiometric dissolution of Al and Fe cations. Longer air-aging was found to be beneficial for stabilizing the passive film. In chloride-containing electrolytes, ten times higher Al dissolution rates were detected at open-circuit potential (OCP), indicating that the spontaneously formed passive film becomes unstable. However, electrochemical polarization at low passive potentials induces electrical field generated oxide film modification, increasing chemical stability at the oxyhydroxide-solution interface. In the high potential passive region, localized attack is initiated with subsequent active metal dissolution. (C) 2013 Elsevier B.V. All rights reserved.

The oxidation of the Al4(Cr, Fe) quasicrystal approximant has been studied using scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). STM data indicate that the initial oxidation on the (1 0 0) surface proceeds in a highly ordered fashion. Oxygen preferentially adsorbs onto the surface of terraces, and step edges remain intact. The STM images show ordered stripes after initial oxidation. XPS data indicate that only Al is oxidised, with at least two oxidation states present. The Cr and Fe peaks remain unchanged. The oxidation of Al, rather than Cr or Fe, is consistent with the enthalpies of formation for each oxide. The stripes visible on the STM images are therefore identified to be the initial stages of aluminium oxide formation. XPS performed after higher O2 exposure indicates that the (1 0 0) termination shows hindered Al oxide film thickness growth rates compared to the (0 1 0) and (0 0 1) surfaces.

Al-based complex metallic alloys (CMAs) are crystalline intermetallic phases characterised by very complex crystal lattices, showing intriguing surface properties such as low wetting, low friction and hardness which include, for the Al–Cr–Fe system, high corrosion resistance. However, their passivation mechanisms (nm-thick oxide layer formation) still need to be understood in relation with localised corrosion susceptibility. New single phases were therefore characterised by electrochemical Microcell technique. The chromium cations in the oxide proved to play a significant role in stabilising the passive layer at low pH. Corrosion resistance of single- and polycrystalline samples was first compared by means of inductively coupled plasma mass spectrometer (ICPMS) analysis during immersion. Higher dissolution rates have been measured for the low Cr containing (12.5 at%) polycrystals compared to the single crystals. The resistance to localised corrosion attack of the single crystals in an aggressive 0.01 M HCl + 1 M NaCl solution at pH 2 was high, with an anisotropic behaviour of the anodic breakdown potential related to the grain orientation. The orthorhombic (0 0 1) termination with higher Cr/Al atoms ratio formed a passive layer with increased resistance against pitting. Ageing of the samples and the formation of surface Al oxy-hydroxide appeared to decrease the pitting corrosion resistance.

Reactive deposition of Ti on the Cu(001) surface saturated with chemisorbed oxygen results in the formation of an ordered ultrathin film with a slightly distorted hexagonal (quasihexagonal) unit cell. We find that, under appropriate substrate temperature, evaporation rates, and O2 pressure, it is possible to cover the whole substrate surface with the TiO2 quasihexagonal phase. An O−Ti−O trilayer model for the (quasi) hexagonal structure is consistent with angle scanned XPD data relative to the Ti 2p signal and with the LEED I−V experimental intensity curves. From a careful inspection of the LEED pattern, we derive a distortion of the hexagonal unit cell corresponding to a p(2 × 7) coincidence mesh with the substrate. The p(2 × 7) coincidence was used to model XPD data. For the analysis of LEED-IV data and for DFT calculation, the p(2 × 7) was approximated by a c(2 × 6) coincidence mesh. The c(2 × 6) approximation is very close to a p(2 × 7) in terms of lattice parameters but contains a reduced number of n...

A cobalt(III)-polydioxolene polymer undergoing valence tautomeric interconversion was irradiated at cryogenic temperatures. Magnetic and EPR data suggest the occurrence of photoinduced VT interconversion, with a maximum degree of about 10%. The kinetics data evidence a larger amount of cooperativity than previously observed in simple monomer, a phenomenon that we attribute to the 1D nature of the system. In the range 9–40 K the relaxation time follows two different regimes, both temperature dependent. The small values of the activation energies suggest the existence of phonon assisted relaxation mechanisms based on a tunneling process involving the totalsymmetric breathing mode of the complex.

[Co(Me(4)cyclam)(tropolonate)](PF(6)) was synthesised and structurally characterised. Its electronic and W-band EPR spectra have been analysed by means of the angular overlap calculation of the Spin Hamiltonian parameters that provided also a satisfactory reproduction of the temperature dependence of the magnetic susceptibility. The present results can be interpreted assuming a pseudo-octahedral character for the Co(II) center. This prompted us to reconsider the model formerly used for the analysis of the magnetic coupling between hs-Co(II) and the paramagnetic o-semiquinonate ligand in the corresponding derivatives [Co(Me(4)cyclam)(PhenSQ)](PF(6)) and [Co(Me(4)cyclam)(DTBSQ)](PF(6)). These results indicate that the effect of the magnetic coupling is active only below 50 K and that a more refined model of exchange coupling between Co(II) and semiquinonato ligands is needed to quantitatively analyze the magnetic behaviour of this class of systems.

The valence tautomerism of low-spin Co III (Cat-N-BQ)(Cat-N-SQ) (where Cat-N-BQ is 2-(2-hydroxy-3,5-di- tert -butylphenylimino)-4,6-di- tert -butylcyclohexa-3,5-dienone and Cat-N-SQ is the dianionic radical analogue) was investigated by means of UV–vis pump–probe transient absorption spectroscopy and 1 H NMR technique in chloroform and dichloromethane. By exciting the CT transition of the complex at 480 nm, an intramolecular electron transfer process is selectively triggered. The photo-induced charge transfer is pursued by a cascade of two main molecular events characterized by the ultrafast transient absorption spectroscopy: the first gives rise to the metastable high-spin Co II (Cat-N-BQ) 2 that, secondly, reaches the chemical equilibrium with the reactant species. The rate constant of back valence tautomerization estimated by measuring the lifetime of high-spin Co II (Cat-N-BQ) 2 species and the equilibrium constant for the Co III (Cat-N-BQ)(Cat-N-SQ) ⇄ Co II (Cat-N-BQ) 2 interconversion, is significantly large (on the order of 10 9 s −1 ). It is interpreted under the point of view of the theory formulated by Jortner and Buhks et al. for non-adiabatic radiationless processes.

The valence tautomerism of low-spin CoIII(Cat-N-BQ)(Cat-N-SQ) was investigated by means of UV-vis pump-probe transient absorption spectroscopy in chloroform. By exciting the CT transition of the complex at 480 nm, an intramolecular electron transfer process is selectively triggered. The photo-induced charge transfer is pursued by a cascade of two main molecular events characterized by the ultrafast transient absorption spectroscopy: the first gives rise to the metastable high-spin CoII(Cat-N-BQ)2 that, secondly, reaches the chemical equilibrium with the reactant species.

From June 3–5, 2013, the Swiss Federal Laboratories for Materials Science and Technology (EMPA) and the Swiss Light Source held an international workshop on soft X-rays and electrochemical energy storage and converters at EMPA in Dubendorf, Switzerland. A total of 30 scientists from Europe, India, Korea, and the Americas presented state-of-the-art soft X-ray and electron spectroscopy methodologies, some of which combined operando or in-situ experiments with electroanalytical methods employing synchrotron radiation.

A Hard X-ray Photoelectron Spectroscopy (HAXPES) characterisation of the passivation layers formed by electrochemical polarisation of Al–Cr–Fe complex metallic alloys is presented. By employing X-ray excitation energies from 2.3 to 10.0 keV, the depth distributions of Al- and Cr-oxide and hydroxide species in the (Al,Cr)-containing passive layers could be determined. Simultaneous analyses of the shallow Al 2s and deep Al 1s core level lines (respectively, more bulk- and surface-sensitive) provided complementary information to effectively determine the depth-resolved contributions of hydroxide and oxide species within the passivation layer. A Cr threshold concentration of 18 (at.%) was found for effective passivation at pH 1. Keywords: Electrochemical passivation, Hard X-ray Photoelectron Spectroscopy (HAXPES), Al alloys, Complex metallic alloys, Composition depth profiling, Oxide/hydroxide

The reaction of 3,3,3', 3'-tetramethyl-5,5',6,6'-tetrahydroxy-1,1'spiro-bis(indane), L, with cobalt salts in the presence of diazine ligands affords polymeric derivatives of general formula [CoL(diazine)](infinity)center dot nH(2)O, L being coordinated as a mixed-valence SQ-Cat species. The bipiridyl and o-phenantroline derivatives have been characterised by means of magnetic, EPR and calorimetric measurements. The characterisation showed that both systems are obtained in a metastable charge distribution, presumably trapped due to the class I character of the mixed valence form of the ligand. The occurrence of entropy-driven valence tautomeric interconversion induces the transition to the most stable charge distribution. The photomagnetic characterisation evidenced that valence tautomeric process can be photoinduced and that the lifetime of the photoinduced metastable state, obtained in low yield, is of ca. 2 x 10(5) s at 9 K.

A series of cobalt complexes [Co(Me(n)tpa)(diox)]PF(6)sol (diox=3,5-di-tert-butyl-1,2-dioxolene; sol=ethanol, toluene; tpa=tris(2-pyridylmethyl)amine) were prepared by using tripod-like Me(n)tpa (n=0, 1, 2, 3), derived from tpa by successive introduction of methyl groups into the 6-position of the pyridine moieties, as an ancillary ligand. The steric hindrance induced by this substitution modulates the redox properties of the metal acceptor, thus determining the charge distribution of the metal-dioxolene moiety at room temperature. All of these complexes were characterised by using diffractometric studies, electronic spectroscopic analysis, and magnetic susceptibility measurements. In the solid state, the [Co(Me(n)tpa)(diox)](+) ions (n=0, 1) can be described as diamagnetic cobalt(III)-catecholato derivatives, whereas a cobalt(II)-semiquinonato description seems appropriate for the paramagnetic [Co(Me(3)tpa)(diox)](+) complex. The complex [Co(Me(2)tpa)(diox)]PF(6)C(2)H(5)OH undergoes entropy-driven valence tautomeric interconversion at room temperature. Optically induced valence tautomerism was observed by irradiation of [Co(Me(n)tpa)(diox)]PF(6) complexes (n=0, 1, 2) at cryogenic temperatures. The different relaxation kinetics of the photoinduced metastable phases are related to the respective free-energy changes of the interconversion, as estimated by cyclic voltammetric experiments at room temperature, and to the different lattice interactions, as supported by structural data. These results show the importance of molecular techniques for controlling the relaxation properties of photoinduced metastable species. At the same time, this behaviour strongly suggests that this paradigm exhibits intrinsic limits because of the less controllable factors that affect the process.

The observation of very long lifetimes of the metastable states of two cobalt-dioxolene complexes undergoing photoinduced and high T(c) thermally-induced valence tautomer interconversion opens new research perspectives.

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