7 research outputs found

    Protection of mild steel from corrosion in an aggressive chloride media through chitosan-CeO2 nanocomposite: Experimental and computational studies

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    In this study, synthesis of cerium dioxide nanoparticles (CeO2 NPs) and preparation of chitosan-CeO2 nanocomposite (CH-CeO2 NC) were done and examined their inhibitive nature on mild steel surface in 1 mol/L HCl solution. Characterization was done through ultraviolet-visible (UV–Vis) and Fourier transform infrared (FT-IR) spectroscopy. Mass loss, electrochemical studies were used to determine the anticorrosive parameters of the prepared materials. Morphology, composition, and size were evaluated with scanning electron microscopy/energy dispersive spectrometry and X-ray diffraction. The inhibition efficiency was increased from 76.9% to 98.9% with the introduction of NPs in the CH. Atomic force microscopy and density functional theory results are in compliance with experimental studies and confirm the better performance of CH-CeO2 NC over chitosan

    Effect of nitric oxide donor and gamma irradiation on modifications of ERK and JNK in murine peritoneal macrophages

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    Mitogen activated protein kinases (MAPKs) play an important role in activation, differentiation and proliferation of macrophages. Macrophages, upon activation, produce large amounts of nitric oxide that inhibit the growth of variety of microorganisms and tumor cells. This nitric oxide which is known to interfere with tyrosine phosphorylation may result in changes in the pattern of activation of MAPKs. In a previous study we have found that tyrosine phosphorylation of MAPKs was completely abolished in the presence of nitric oxide donor and radiation but this did not affect the function of macrophages. In this study the other post translational modifications namely nitration and ubiquitination of JNK and ERK have been looked at. Both ERK and JNK were found to be nitrated. However, there was no increase in ubiquitination of ERK and JNK, indicating that ubiquitination, in this case was not a natural consequence of nitration and may serve in signaling. Additionally, when the nitration was extensive, phosphorylation was also inhibited. The activation of substrates of ERK and JNK were looked at to determine the consequences of such modifications. Inhibition of phosphorylation and extensive nitration of JNK did not prevent activation of its substrate, c-jun. This study indicates that ERK and JNK may be under regulation by different type of modifications in macrophages
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