Infrared Spectroscopy of SARS-CoV-2 Viral Protein: from Receptor Binding Domain to Spike Protein.

Spike (S) glycoprotein is the largest structural protein of SARS-CoV-2 virus and the main one involved in anchoring of the host receptor ACE2 through the receptor binding domain (RBD). S protein secondary structure is of great interest for shedding light on various aspects, from functionality to pathogenesis, finally to spectral fingerprint for the design of optical biosensors. In this paper, the secondary structure of SARS-CoV-2 S protein and its constituting components, namely RBD, S1 and S2 regions, are investigated at serological pH by measuring their amide I infrared absorption bands through Attenuated Total Reflection Infrared (ATR-IR) spectroscopy.

Characterization of CuAg Alloys with Low Ag Concentrations.

Copper-based alloys designed to combine high electronic and thermal conductivities with high mechanical strength find a wide range of applications in different fields. Among the principal representatives, strongly diluted CuAg alloys are of particular interest as innovative materials for the realization of accelerating structures when the use of high-gradient fields requires increasingly high mechanical and thermal performances to overcome the limitations induced by breakdown phenomena. This work reports the production and optical characterization of CuAg crystals at low Ag concentrations, from 0.

Secondary Structures of MERS-CoV, SARS-CoV, and SARS-CoV-2 Spike Proteins Revealed by Infrared Vibrational Spectroscopy.

All coronaviruses are characterized by spike glycoproteins whose S1 subunits contain the receptor binding domain (RBD). The RBD anchors the virus to the host cellular membrane to regulate the virus transmissibility and infectious process. Although the protein/receptor interaction mainly depends on the spike's conformation, particularly on its S1 unit, their secondary structures are poorly known.

Photon-shot-noise-limited transient absorption soft X-ray spectroscopy at the European XFEL.

Femtosecond transient soft X-ray absorption spectroscopy (XAS) is a very promising technique that can be employed at X-ray free-electron lasers (FELs) to investigate out-of-equilibrium dynamics for material and energy research. Here, a dedicated setup for soft X-rays available at the Spectroscopy and Coherent Scattering (SCS) instrument at the European X-ray Free-Electron Laser (European XFEL) is presented. It consists of a beam-splitting off-axis zone plate (BOZ) used in transmission to create three copies of the incoming beam, which are used to measure the transmitted intensity through the excited and unexcited sample, as well as to monitor the incoming intensity.

A new approach to deposit homogeneous samples of asbestos fibres for toxicological tests .

In this paper we describe the results obtained with a novel method to prepare depositions of asbestos fibres for toxicological tests . The technique is based on a micro-dispenser, working as an inkjet printer, able to deposit micro-sized droplets from a suspension of fibres in a liquid medium; we used here a highly evaporating liquid (ethanol) to reduce the experimental time, however other solvents could be used. Both the amount and spatial distribution of fibres on the substrate can be controlled by adjusting the parameters of the micro-dispenser such as deposition area, deposition time, uniformity and volume of the deposited liquid.

Sars-Cov2 world pandemic recurrent waves controlled by variants evolution and vaccination campaign.

While understanding the time evolution of Covid-19 pandemic is needed to plan economics and tune sanitary policies, a quantitative information of the recurrent epidemic waves is elusive. This work describes a statistical physics study of the subsequent waves in the epidemic spreading of Covid-19 and disclose the frequency components of the epidemic waves pattern over two years in United States, United Kingdom and Japan. These countries have been taken as representative cases of different containment policies such as "Mitigation" (USA and UK) and "Zero Covid" (Japan) policies.

Terahertz continuous wave spectroscopy: a portable advanced method for atmospheric gas sensing.

Motivated by the increasing demand to monitor the air-quality, our study proved the feasibility of a new compact and portable experimental approach based on Terahertz (THz) continuous wave high resolution spectroscopy, to detect the presence of the air's contaminants as greenhouse gases (GHG) and volatile organic compounds (VOCs). In this specific work, we first characterized, determining their molar absorption coefficient in the spectral region (0.06-1.

High Sensitivity Monitoring of VOCs in Air through FTIR Spectroscopy Using a Multipass Gas Cell Setup.

Human exposure to Volatile Organic Compounds (VOCs) and their presence in indoor and working environments is recognized as a serious health risk, causing impairments of varying severities. Different detecting systems able to monitor VOCs are available in the market; however, they have significant limitations for both sensitivity and chemical discrimination capability. During the last years we studied systematically the use of Fourier Transform Infrared (FTIR) spectroscopy as an alternative, powerful tool for quantifying VOCs in air.

Insight into atmospheric deposition and spatial distribution of bioavailable iron in the glaciers of northeastern Tibetan Plateau.

Iron (Fe) is an essential micronutrient in glacial ecosystems and modulates global biogeochemical cycles. To find out the deposition concentration, multiple origins and release form of iron in various glacier areas of central Asia, this study investigated the total Fe (TFe) and dissolved-Fe (dFe, diameter < 0.45 or <0.

Uranium isotopes of aeolian dust deposited in northern Tibetan Plateau glaciers: Implications for tracing aeolian dust provenance.

Asian dust comprises a large portion of the northern hemisphere atmospheric dust load, thereby exerting substantial influence on the Earth's climate, global biogeochemistry and hydrological cycle through accelerated snow and ice melt. Dust deposited on alpine glaciers encodes information on broad scale atmospheric-environmental processes. The (U/U) values of dust fine particulates can reflect the comminuting time and intermediate processes; thus, it provides a new method for the provenance of aeolian dust in the glacial snowpack/cryoconite.

A multi-purpose high-pressure and high temperature gas-flow cell for operando optical Raman spectroscopy.

A multi-purpose in operando optical cell with temperature and gas pressure control is described. This device allows for in operando Raman spectroscopy measurements for different applications. Its original design includes a temperature control from room temperature up to 1000°C and a heating stage that provides uniform and stable thermal conditions.

Morphological, electronic, and magnetic properties of multicomponent cobalt oxide nanoparticles synthesized by high temperature arc plasma.

Many technological applications demand large amount of nanoparticles with well-defined properties, which is feasible only by using large-scale production methods. In this framework, we have performed structural and local geometric investigations of cobalt oxide nanoparticles synthesized by high temperature arc plasma route in helium and in air atmosphere with different arc currents, a competitive and low cost technological approach to synthesize large quantity of different types of nanoparticles. The complex scenario of phase fraction, shape, size distribution and hysteresis loop features of high temperature arc plasma synthesis of nanoparticles can be determined by the arc current and the selected gas.

Real-time quantitative detection of styrene in atmosphere in presence of other volatile-organic compounds using a portable device.

Exposure to styrene is a major safety concern in the fibreglass processing industry. This compound is classified by the International Agency for Research on Cancer as a possible human carcinogen. Several types of analytical equipment exist for detecting volatile organic compounds (VOCs) in the atmosphere; however, most of them operate ex-situ or do not provide easy discrimination between different molecules.

Metastable states in plateaus and multi-wave epidemic dynamics of Covid-19 spreading in Italy.

The control of Covid 19 epidemics by public health policy in Italy during the first and the second epidemic waves has been driven by using reproductive number R(t) to identify the supercritical (percolative), the subcritical (arrested), separated by the critical regime. Here we show that to quantify the Covid-19 spreading rate with containment measures there is a need of a 3D expanded parameter space phase diagram built by the combination of R(t) and doubling time T(t). In this space we identify the Covid-19 dynamics in Italy and its administrative Regions.

Epidemic spreading in an expanded parameter space: the supercritical scaling laws and subcritical metastable phases.

While the mathematical laws of uncontrolled epidemic spreading are well known, the statistical physics of coronavirus epidemics with containment measures is currently lacking. The modelling of available data of the first wave of the Covid-19 pandemic in 2020 over 230 days, in different countries representative of different containment policies is relevant to quantify the efficiency of these policies to face the containment of any successive wave. At this aim we have built a 3D phase diagram tracking the simultaneous evolution and the interplay of the doubling time,, and the reproductive number,measured using the methodological definition used by the Robert Koch Institute.

Spontaneous shape transition of Mn Ge islands to long nanowires.

We report experimental evidence for a spontaneous shape transition, from regular islands to elongated nanowires, upon high-temperature annealing of a thin Mn wetting layer evaporated on Ge(111). We demonstrate that 4.5 monolayers is the critical thickness of the Mn layer, governing the shape transition to wires.

Jarosite formation in deep Antarctic ice provides a window into acidic, water-limited weathering on Mars.

Many interpretations have been proposed to explain the presence of jarosite within Martian surficial sediments, including the possibility that it precipitated within paleo-ice deposits owing to englacial weathering of dust. However, until now a similar geochemical process was not observed on Earth nor in other planetary settings. We report a multi-analytical indication of jarosite formation within deep ice.

Rational design of hierarchical FeSe encapsulated with bifunctional carbon cuboids as an advanced anode for sodium-ion batteries.

Earth-abundant transition-metal selenides (TMSs) have aroused great interest towards their application in sodium-ion batteries (SIBs). Herein, we present Fe-based Prussian blue analogs (PBA) modified by graphene oxide as precursors to synthesize FeSe2 nanoparticles within a nitrogen-doped carbon (NC) matrix and graphene layer (FeSe2/NC@G). The bifunctional carbon wrapped FeSe2/NC@G shows excellent sodium-storage performance with a large reversible capacity of 331 mA h g-1 at 5.

Efficiency of COVID-19 mobile contact tracing containment by measuring time-dependent doubling time.

The COVID-19 epidemic of the novel coronavirus (severe acute respiratory syndrome SARS-CoV-2) has spread around the world. While different containment policies using non-pharmaceutical interventions have been applied, their efficiencies are not known quantitatively. We show that the doubling time T (t) with the success s factor, the characteristic time of the exponential growth of T (t) in the arrested regime, is a reliable tool for early predictions of epidemic spread time evolution and provides a quantitative measure of the success of different containment measures.

Retarding Ostwald Ripening to Directly Cast 3D Porous Graphene Oxide Bulks at Open Ambient Conditions.

Graphene aerogels (GAs) with attractive properties have shown tremendous potentials in energy- and environment-related applications. Unfortunately, current assembly methods for GAs such as sol-gel and freeze-casting processes must be conducted in enclosed spaces with unconventional conditions, thus being literally inoperative for and continuous productions. Herein, a direct slurry-casting method at open ambient conditions is established to arbitrarily prepare three-dimensional (3D) porous graphene oxide (GO) bulks without macroscopic dimension limits on a wide range of solid surfaces by retarding Ostwald ripening of 3D liquid GO foams when being dried in air.

Interplay among work function, electronic structure and stoichiometry in nanostructured VO films.

The work function is the parameter of greatest interest in many technological applications involving charge exchange mechanisms at the surface. The possibility to produce samples with a controlled work function is then particularly interesting, albeit challenging. We synthetized nanostructured vanadium oxide films by a room temperature supersonic cluster beam deposition method, obtaining samples with tunable stoichiometry and work function (3.

Characterization of volatile organic compounds (VOCs) in their liquid-phase by terahertz time-domain spectroscopy.

In this work the terahertz spectra of benzene, toluene, p-xylene and styrene-four volatile organic compounds (VOCs) of interest in environmental pollution studies-have been measured in their liquid phase at room temperature using terahertz time-domain spectroscopy (THz-TDS). Their frequency-dependent refractive index and absorption coefficient have been extracted and analyzed in the spectral range from 0.2 to 2.

Ultimate Photo-Thermo-Acoustic Efficiency of Graphene Aerogels.

The ability to generate, amplify, mix, and modulate sound with no harmonic distortion in a passive opto-acoustic device would revolutionize the field of acoustics. The photo-thermo-acoustic (PTA) effect allows to transduce light into sound without any bulk electro-mechanically moving parts and electrical connections, as for conventional loudspeakers. Also, PTA devices can be integrated with standard silicon complementary metal-oxide semiconductor (CMOS) fabrication techniques.

Effects of temperature and pressure on the optical and vibrational properties of thermoelectric SnSe.

We have conducted a comprehensive investigation of the optical and vibrational properties of the binary semiconductor SnSe as a function of temperature and pressure by means of experimental and ab initio probes. Our high-temperature investigations at ambient pressure have successfully reproduced the progressive enhancement of the free carrier concentration upon approaching the Pnma → Bbmm transition, whereas the pressure-induced Pnma → Bbmm transformation at ambient temperature, accompanied by an electronic semiconductor → semi-metal transition, has been identified for bulk SnSe close to 10 GPa. Modeling of the Raman-active vibrations revealed that three-phonon anharmonic processes dominate the temperature-induced mode frequency evolution.

Lattice Dynamics and Thermal Conductivity in CuZnCo SnSe.

The quaternary compound CuZnSnSe (CZTSe), as a typical candidate for both solar cells and thermoelectrics, is of great interest for energy harvesting applications. Materials with a high thermoelectric efficiency have a relatively low thermal conductivity, which is closely related to their chemical bonding and lattice dynamics. Therefore, it is essential to investigate the lattice dynamics of materials to further improve their thermoelectric efficiency.