Magnetron-sputtered copper/diamond-like carbon composite thin films with super anti-corrosion properties

International audienceSuper anti-corrosive copper/diamond-like carbon (Cu/DLC) composite films are applied on mild steel utilizing magnetron sputtering in a mixed atmosphere of Ar and CH4. Mechanical, contact angle, and corrosion performance of the resulting Cu/DLC thin films are probed and discussed in terms of Ar/CH4 and Cu/C ratios. Overall, Cu/C ratio has augmented by Ar/CH4 ratio. Raman spectra of films revealed typical features of G and D bands indicating formation of DLC phase. The Cu/DLC thin films with higher Cu content exhibited a higher degree of sp2 carbon clustering, but lower diamond-like sp3 bonding. Internal stress values of Cu/DLC thin films decreased with increasing Cu/C ratio. Addition of a few amount of Cu to DLC resulted in a rise in plastic hardness and H3/E2 ratio of Cu/DLC composite thin films, but optimum value was observed for composite films having an intermediate Cu concentration. The contact angle of iron substrate increased when coated with Cu/DLC thin films, but Cu content of films played a minor role. The Cu/DLC thin films formed via magnetron sputtering revealed super anti-corrosion performance, the term which is defined, conceptualized, and quantified in the current study

Targeted analysis of Ubiquitin-Specific Peptidase (USP8) in a population of Iranian people with Cushing’s disease and a systematic review of the literature

Abstract Objective Activating mutation in Ubiquitin-specific peptidase (USP8) is identified to enhance cell proliferation and adrenocorticotropic hormone (ACTH) secretion from corticotroph pituitary adenoma. We investigated the USP8 variant status in a population of Iranian people with functional corticotroph pituitary adenoma (FCPA). Moreover, a systematic review was conducted to thoroughly explore the role of USP8 variants and the related pathways in corticotroph adenomas, genotype-phenotype correlation in USP8-mutated individuals with FCPA, and the potential role of USP8 and epidermal growth factor receptor (EGFR) as targeted therapies in PFCAs. Methods Genetic analysis of 20 tissue samples from 19 patients with PFCAs was performed using Sanger sequencing. Moreover, a systematic literature review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Scopus, web of Sciences, and Cochrane databases were searched. The last search was performed on 20 September 2023 for all databases. Results In our series, we found two somatic mutations including a 7-bp deletion variant: c.2151_2157delCTCCTCC, p. Ser718GlnfsTer3, and a missense variant: c.2159 C > G, p. Pro720Arg (rs672601311) in exon 14. The Systematic review indicated USP8 variant in 35% of corticotroph adenomas, with the highest frequency (25%) in 720 code regions, p. Pro720Arg. Data regarding the impact of USP8 mutational status on clinical characteristics and outcomes in FCPAs are inconsistent. Moreover, Pasireotide as well as inhibitors of EGFR such as Gefitinib and Lapatinib, as well as USP8 inhibitors including -ehtyloxyimino9H-indeno (1, 2-b) pyrazine-2, 3-dicarbonitrile, DUBs-IN-2, and RA-9 indicated promising results in treatment of corticotroph adenomas. Conclusion Although the USP8-EGFR system has been identified as the main trigger and target of corticotroph tumorigenesis, more precise multicenter studies are required to yield more consistent information regarding the phenotype-genotype correlation and to develop effective targeted therapies

High-performance hybrid coatings based on diamond-like carbon and copper for carbon steel protection

International audienceHigh performance double-layer coatings composed of copper (Cu) interlayer and the Cu/diamond-like carbon (DLC) composite top layer were prepared via magnetron sputtering for protection of carbon steel. The effect of Cu content in the composite layer on the internal stress, contact angle, mechanical, tribological, and corrosion performance of coatings was discussed. Raman spectroscopy confirmed formation of DLC phase. Double-layer Cu-rich coatings exhibited high degree of sp2 carbon clustering, but low diamond-like sp3 bonding. The internal stress of double layer Cu-(Cu/DLC composite) coatings was decreased with Cu content increase. The double-layer Cu-(Cu/DLC composite) thin films with low Cu content did not pose a significant effect on hardness and Young's modulus of the steel substrate, while increase of Cu content enhanced hardness of coating up to 28 GPa. The contact angle of steel substrate showed an increase when coated with double-layer Cu-(Cu/DLC composite) thin film, but not that much at such inadequate Cu content. Inclusion of Cu interlayer improved to some extent corrosion properties, where increase of Cu content assisted in protection. Double-layer coatings with the highest performance were compared with single-layer Cu/DLC coating. Elimination of interlayer deteriorated mechanical properties, but increased electrochemical performance, signifying the importance of controlling Cu/DLC composition and Cu interlayer inclusion

Tailoring hardness and electrochemical performance of TC4 coated Cu/a-C thin coating with introducing second metal Zr

International audienceThe objective of this study was to develop multifunctional protective biocompatible (Cu, Zr)/a-C: H coatings with good mechanical properties and high corrosion resistance using a sputtering system on the surface of TC4 alloy. Coatings with a higher Zr/Cu ratio showed higher hardness, Young's modulus, and superior bio-corrosion resistance. It was demonstrated that charge transfer resistance of the coating with a higher Zr/Cu ratio enhanced from ∼40 kΩ. cm2 to ∼990 kΩ. cm2 after 168 h of immersion time. The results also showed strong synergistic effects of Cu and Zr, as well as the formation of the zirconium carbide phase on the surface