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In this paper, an assessment of the natural radioactivity level, radon exhalation, metal contamination, and mineralogy of a granodiorite rock sample from Stilo, in the Calabria region, Southern Italy is presented as a case study. This rock was employed as a building material in the area under study. The specific activity of 226Ra, 232Th and 40K natural radioisotopes was assessed through high-purity germanium (HPGe) gamma-ray spectrometry. Then, several indices such as the absorbed gamma dose rate (D), the annual effective dose equivalent (AEDE), the activity concentration index (ACI) and the alpha index (Iα), were quantified to determine any potential radiological health risk related to radiation exposure from the analyzed rock. Furthermore, E-PERM electret ion chambers and inductively coupled plasma mass spectrometry (ICP-MS) measurements were carried out to properly quantify the radon exhalation rate and any possible metal pollution, respectively. In particular, to further address metal pollution factors, the geo-accumulation index (Igeo) was calculated to properly address the toxicity levels of the ecosystem originating from the detected metals. Finally, with the aim of successfully discriminating the provenance of such naturally occurring radionuclides, a combined approach involving X-ray diffraction (XRD) and µ-Raman spectroscopy was employed for the identification of the main radioisotope-bearing minerals characterizing the investigated granodiorite. The results achieved in this case study can be taken as the basis for further inquiries into background levels of radioactivity and chemical contamination in natural stone employed as building materials. [ABSTRACT FROM AUTHOR]

Graphene‐based materials represent a useful tool for the realization of novel neural interfaces. Several studies have demonstrated the biocompatibility of graphene‐based supports, but the biological interactions between graphene and neurons still pose open questions. In this work, the influence of graphene films with different characteristics on the growth and maturation of primary cortical neurons is investigated. Graphene films are grown by chemical vapor deposition progressively lowering the temperature range from 1070 to 650 °C to change the lattice structure and corresponding electrical conductivity. Two graphene‐based films with different electrical properties are selected and used as substrate for growing primary cortical neurons: i) highly crystalline and conductive (grown at 1070 °C) and ii) highly disordered and 140‐times less conductive (grown at 790 °C). Electron and fluorescence microscopy imaging reveal an excellent neuronal viability and the development of a mature, structured, and excitable network onto both substrates, regardless of their microstructure and electrical conductivity. The results underline that high electrical conductivity by itself is not fundamental for graphene‐based neuronal interfaces, while other physico–chemical characteristics, including the atomic structure, should be also considered in the design of functional, bio‐friendly templates. This finding widens the spectrum of carbon‐based materials suitable for neuroscience applications. [ABSTRACT FROM AUTHOR]

Nitric acid vapor phase oxidation of carbon nanotubes using Mg(NO3)2‒HNO3‒H2O ternary mixture is proposed asa further development and significant improvementof the method employing the sole azeotropic HNO3solution. Based on the so-called “salt effect,” the addition of Mg(NO3)2to HNO3‒H2O solution allows varying the acid vapor concentration within a wide range, even beyond the azeotropic one (>68wt%). Ternary mixture containing 20wt% Mg(NO3)2and variable amount of liquid HNO3(30–58wt%) is used for the functionalization process, achieving nitric acid vapor concentrations in the range 25–93wt%. The increase of acid concentration in vapor phase produces a significant augment of the functionalization degree and a linear increase of the concentration of carboxylic acids groups, which can thus be simply tuned. [ABSTRACT FROM AUTHOR]

This paper studies holey graphene with various neck widths (the smallest distance between two neighbor holes). For the considered structures, the energy gap, the Fermi level, the density of electronic states, and the distribution of the local density of electronic states (LDOS) were found. The electroconductive properties of holey graphene with round holes were calculated depending on the neck width. It was found that, depending on the neck width, holey graphene demonstrated a semiconductor type of conductivity with an energy gap varying in the range of 0.01–0.37 eV. It was also shown that by changing the neck width, it is possible to control the electrical conductivity of holey graphene. The anisotropy of holey graphene electrical conductivity was observed depending on the direction of the current transfer. [ABSTRACT FROM AUTHOR]

A one-step method for plasma synthesis of nitrogen-doped carbon nanomesh is presented. The method involves a molten polymer, which is a source of carbon, and inductively coupled nitrogen plasma, which is a source of highly reactive nitrogen species. The method enables the deposition of the nanocarbon layer at a rate of almost 0.1 µm/s. The deposited nanocarbon is in the form of randomly oriented multilayer graphene nanosheets or nanoflakes with a thickness of several nm and an area of the order of 1000 nm2. The concentration of chemically bonded nitrogen on the surface of the film increases with deposition time and saturates at approximately 15 at.%. Initially, the oxygen concentration is up to approximately 10 at.% but decreases with treatment time and finally saturates at approximately 2 at.%. Nitrogen is bonded in various configurations, including graphitic, pyridinic, and pyrrolic nitrogen. [ABSTRACT FROM AUTHOR]

Good stability and reproducibility are important factors in determining the place of any material in their respective field and these two factors also enable them to use in various applications. At present, transition metal carbides (TMCs) have high demand either in the two-dimensional (2D) form (MXene) or as nanocomposites, nanoparticles, carbide films, carbide nano-powder, and carbide nanofibers. They have shown good stability at high temperatures in different environments and also have the ability to show adequate reproducibility. Metal carbides have shown a broad spectrum of properties enabling them to engage the modern approach of multifacet material. Several ways have been routed to synthesize metal carbides in their various forms but few of those gain more attention due to their easy approach and better properties. TMCs find applications in various fields, such as catalysts, absorbents, bio-sensors, pesticides, electrogenerated chemiluminescence (ECL), anti-pollution and anti-bacterial agents, and in tumor detection. This article highlights some recent developments in the synthesis methods and applications of TMCs in various fields. [ABSTRACT FROM AUTHOR]