A variety of environmental agents has been found to influence the development of autoimmune diseases; in particular, the studies investigating the potential association of systemic autoimmune rheumatic diseases with environmental micro and nano-particulate matter are very few and contradictory. In this study, the role of diesel exhaust particles (DEPs), one of the most important components of environment particulate matter, emitted from Euro 4 and Euro 5 engines in altering the Normal Human Bronchial Epithelial (NHBE) cell biological activity was evaluated. NHBE cells were exposed in vitro to Euro 4 and Euro 5 particle carbon core, sampled upstream of the typical emission after-treatment systems (diesel oxidation catalyst and diesel particulate filter), whose surfaces have been washed from well-assessed harmful species, as polycyclic aromatic hydrocarbons (PAHs) to: (1) investigate their specific capacity to affect cell viability (flow cytometry); (2) stimulate the production of the pro-inflammatory cytokine IL-18 (Enzyme-Linked ImmunoSorbent Assay -ELISA-); (3) verify their specific ability to induce autophagy and elicit protein citrullination and peptidyl arginine deiminase (PAD) activity (confocal laser scanning microscopy, immunoprecipitation, Sodium Dodecyl Sulphate-PolyAcrylamide Gel Electrophoresis -SDS-PAGE- and Western blot, ELISA). In this study we demonstrated, for the first time, that both Euro 4 and Euro 5 carbon particles, deprived of PAHs possibly adsorbed on the soot surface, were able to: (1) significantly affect cell viability, inducing autophagy, apoptosis and necrosis; (2) stimulate the release of the pro-inflammatory cytokine IL-18; (3) elicit protein citrullination and PAD activity in NHBE cells. In particular, Euro 5 DEPs seem to have a more marked effect with respect to Euro 4 DEPs.

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Reduction of strongly oxidized carbon black by hydrazine hydrate yields water-insoluble graphene-like sheets that undergo to self-assembling in thin film on surfaces after drying. The height of a drop-casted graphene-like film was determined by atomic force microscopy (AFM) to be around 20 nm, corresponding to approximately 25 graphene-like layers. The oxidized carbon black and the corresponding reduced form were carefully characterized.

The different thermal behaviors and solubilities of large and structurally different polycyclic aromatic hydrocarbon (PAH) mixtures featuring coal tar pitch (CP) and naphthalene synthetic pitch (NP) samples could be read in light of their different molecular weight (MW) distribution and spectroscopic features. The number-average MW obtained by mass spectrometry for CP (417 Da) and NP (691 Da) resulted to be lower in comparison to the values evaluated by size-exclusion chromatography (SEC) (796 and 824 Da for CP and NP, respectively) because of the different response of the detector of mass spectrometry to low-and high-MW components. Hence, SEC showed to be more suitable for the analysis of PAH mixtures overlapping and covering a higher mass range in comparison to mass spectrometry. Insights into structural PAH features were given by means of spectroscopic analysis [infrared (IR), ultraviolet−visible (UV−vis), and fluorescence], allowing for the discrimination between different families of PAHs as ortho-fused PAHs and rylenes interspersed with aliphatic (mainly naphthenic) groups, mainly featuring CP and NP, respectively. Besides showing the different aromaticity and aliphatic/aromatic hydrogen distribution, the improvement of Fourier transform infrared (FTIR) and UV−vis absorption analysis put also in evidence the contribution of carbon-rich particle impurities and PAH aggregates in CP and NP, respectively.

Complex polycyclic aromatic hydrocarbon (PAH) mixtures separated from a coal tar pitch (CP) and naphthalene pitch (NP) by sequential extraction with heptane and toluene were characterized in detail by applying a multiarray analytical approach. Gas chromatography–mass spectrometry (GC-MS), size exclusion chromatography (SEC), laser desorption ionization-time-of-flight mass spectrometry (LDI-TOFMS), and thermogravimetry (TG) were used to relate the volatility and coking yield of pitch components to their solubility and molecular weight distribution. Spectroscopic analysis, including infrared (IR), ultraviolet–visible (UV–vis), and fluorescence spectroscopy, proved to be useful for measuring specific features of aromatic systems, such as the aromatic content, degree of aliphatic substitution, and size distribution of PAHs of different molecular weights. In particular, it has been shown that the spectroscopic analysis is an essential tool for characterizing very large PAH systems concentrated in the pitch toluene-insoluble fraction. This fraction constitutes a case study of very large, structurally different aromatic compounds, and it is the pitch fraction more relevant for practical applications because of its higher coking tendency and peculiar optical properties.

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