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Nanoparticles are extensively used in industrial products or as food additives. However, despite their contribution to improving our quality of life, concerns have been raised regarding their potential impact on occupational and public health. To speed up research assessing nanoparticle-related hazards, this study was undertaken to identify early markers of harmful effects on the lungs. Female Sprague Dawley rats were either exposed to crystalline silica DQ-12 with instillation, or to titanium dioxide P25, carbon black Printex-90, or multi-walled carbon nanotube Mitsui-7 with nose-only inhalation. Tissues were collected at three post-exposure time points to assess short- and long-term effects. All particles induced lung inflammation. Histopathological and biochemical analyses revealed phospholipid accumulation, lipoproteinosis, and interstitial thickening with collagen deposition after exposure to DQ-12. Exposure to the highest dose of Printex-90 and Mitsui-7, but not P25, induced some phospholipid accumulation. Comparable histopathological changes were observed following exposure to P25, Printex-90, and Mitsui-7. Comparison of overall gene expression profiles identified 15 potential early markers of adverse lung outcomes induced by spherical particles. With Mitsui-7, a distinct gene expression signature was observed, suggesting that carbon nanotubes trigger different toxicity mechanisms to spherical particles. [ABSTRACT FROM AUTHOR]

A preparation method of nanocomposites based on poly (3-octylthiophene-2,5-diyl) (POT) and carbon black (CB) as the transducer of an all-solid potassium ion selective electrode is proposed. POT is used as the dispersant of CB, and the obtained nanocomposites have unique characteristics, including high conductivity, high capacitance and high stability. The potassium ion selective electrode based on POT and CB was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronopotentiometry. The results showed that the detection limit of potassium ions was 10−6.2 M, and the slope was 57.6 ± 0.8 mV/façade. The water layer test and anti-interference test show that the electrode has high hydrophobicity, the static contact angle reaches 139.7° and is not easily affected by light, O2 and CO2. [ABSTRACT FROM AUTHOR]

TiC/Al–Cu nanocomposites were fabricated in Al–Ti–C powder systems using carbon black, a mixture of C and carbon nanotubes (C + CNTs), and CNTs via an in-situ method involving combustion synthesis and hot pressing. As the carbon source changed from pure carbon black to the C + CNT mixture and pure CNTs, the size of the TiC nanoparticles decreased gradually. The nanocomposites synthesized based on the C + CNT mixture exhibited the most uniform dispersion of TiC nanoparticles. The 30 vol% TiC/Al–Cu nanocomposite prepared from the C + CNT mixture had the best comprehensive mechanical properties (yield strength (411 MPa), compressive strength (712 MPa), fracture strain (17.2%), hardness (206.8 HV), and wear resistance under the experimental conditions due to having the most uniformly dispersed TiC nanoparticles. The wear mechanism was a combination of plastic deformation, abrasion, and adhesion. This method may be a low-cost and convenient means to control the sizes of in-situ TiC nanoparticles and prepare high-performance TiC/Al–Cu nanocomposites. [ABSTRACT FROM AUTHOR]

• Post-fire curing of cement composites was notably modified by carbon nanomaterials. • CBN and MWCNT improved rehydration and strength recovery of mortars exposed to 200–400 °C. • Recured nanomodified mortars exposed to 200–400 °C and 600 °C had relative residual factors higher than 85% and 40%, respectively. • Decomposition of CBN and MWCNT after 500 °C decreased strength recovery of rehydrated mortars. Concrete elements exposed to fire can partially recover strength and stiffness if recured in water or in a moist environment. This paper reports a pioneering investigation of the influence of post-fire curing on residual mechanical properties and microstructure of cement mortars containing different concentrations of carbon-black nanoparticles (CBN) or multi-walled carbon nanotubes (MWCNT). A total of 84 specimens were subjected to various maximum exposure temperatures (200, 400, or 600 °C) and post-fire curing (water-recuring for 1 day followed by air-recuring for 27 days). X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectrometry (EDS) were used to investigate the microstructure of different types of specimens. Experimental tests were carried out to determine the compressive strength, static modulus of elasticity, and dynamic modulus of elasticity of rehydrated specimens. Nanofillers enhanced the strength recovery of composites exposed to temperatures up to 400 °C, since they improved rehydration reactions. In this case, the rehydration process provided values of relative residual strength and elastic modulus factors higher than 85%. Composites containing 0.4% MWCNT and 3% CBN presented the best strength and stiffness recovery. Therefore, small contents of carbon nanomaterials provided additional nucleation sites for dehydration products to sediment and being rehydrated. Moreover, water adsorbed by the nanomaterials during the water-recuring process was used later to provide greater rehydration. Composites containing 1.2% MWCNT and 9% CBN presented lower mechanical properties recovery, as high contents of nanomaterials made it harder for water to reach decomposed C-S-H gel, hindering the development of rehydration reactions. After 600 °C, lower relative residual factors were obtained, but always higher than 40%. It happened because nanofillers were not able to provide those rehydration improvements, since their thermal decomposition started at about 500 °C. [ABSTRACT FROM AUTHOR]