Effect of AISI H13 Steel Substrate Nitriding on AlCrN, ZrN, TiSiN, and TiCrN Multilayer PVD Coatings Wear and Friction Behaviors at a Different Temperature Level.

Moving components of industrial machines and tools are subjected to wear and friction. This reduces their useful life and efficiency in running conditions, particularly at high temperatures. One of the most popular solutions is to apply an appropriate surface coating to the tribocouple's base materials. In this study, tribometer experiments were used to evaluate the tribological performance of cathodic arc physical vapor deposited (CAPVD) AlCrN, TiSiN, CrTiN, and ZrN coatings on the gas nitrided AISI H13 tool steel to explore the effects of nitriding the steel on wear and friction behavior of these coatings at ambient and elevated temperatures. The coatings characterization is split into three main parts: mechanical, morphological, and chemical characterization. Nanoindentation has been used for mechanical characterization, thin film X-ray diffraction (XRD), and an energy-dispersive X-ray spectrometer mounted on a scanning electron microscope for chemical characterization, optical profilometer, and atomic force microscopy (AFM) for morphological characterization. Significant improvements in the adhesion qualities of the coatings to the substrate were achieved as a result of nitration. Due to this circumstance, the coatings' load-bearing capacity and high-temperature wear resistance ratings were enhanced. The wear results showed that the AISI H13 tool steel nitriding with AlCrN and ZrN layers decreased wear rates by two to three times at 700 °C.

Transformation of SH-SY5Y cell line into neuron-like cells: Investigation of electrophysiological and biomechanical changes.

SH-SY5Y human neuroblastoma cells are commonly used as neuronal models. Here, we examined different aspects of SH-SY5Y cell differentiation. Various differentiation protocols have been proposed previously, including treatments with retinoic acid, brain-derived neurotrophic factor (BDNF), cholesterol and oestradiol. We examined undifferentiated SH-SY5Y cells (UNDIFF); cells differentiated by the treatment with retinoic acid (RA); retinoic acid + BDNF (RB); and retinoic acid + BDNF + cholesterol + oestradiol (RBCE). We performed whole-cell patch-clamp recordings from these cells and nanomechanically characterised them by using atomic force microscopy (AFM). Our results indicated that Na+ currents become most pronounced in the differentiated RB cells, whereas UNDIFF SH-SY5Y cells had significantly larger K+ currents, which is a characteristic feature of cancer cells. AFM observations of these two groups showed that Young's moduli of SH-SY5Y cells increased threefold with differentiation. Furthermore, we showed a direct relationship between Na+ channel activity and elasticity in these cells. We conclude that SH-SY5Y human neuroblastoma cells should be used as a neuronal model only when they are differentiated by the treatment with retinoic acid and BDNF.