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The alloy coatings were manufactured by laser cladding on Q235 mild steel. Coatings with different Cr content consisted of different phases but contains common phases Cr, Cr2Ti and NiTi. With different Cr content, the microstructure of coating with 15% Cr (15-Coating) was different from that of coating with 30% Cr (30-Coating) and coating with 45% Cr (45-Coating), while that of 30-Coaintng and 45-Coating was similar. The hardness of coatings were significantly increased in comparison with that of substrate, and the maximum micro-hardness of coatings was more than 4 times as high as substrate. The wear resistance of coatings were improved dramatically compared with the substrate. With increase of Cr content, the hardness and wear resistance of coatings were both reduced.

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by inflammation infiltration of the synovial tissues and the fibroblast-like synoviocytes. Tectoridin is a botanical active ingredient with anti-inflammatory properties. In this study, the anti-arthritic effects of tectoridin and its mechanism of action are examined in TNF-α-induced human fibroblast-like synovial cells (HFLSs cells) and complete Freund's adjuvant (CFA)-stimulated arthritic mice. Arthritis progression was evaluated via bodyweight, hind paw swelling, organ index, and synovial pathology. IL-1β, IL-6 and other pro-inflammatory factors concentrations, and the expression of MAPK pathway proteins in HFLSs cells and arthritic mice were measured using ELISA and western blotting. Results showed that tectoridin significantly decreased the swelling of the paws and joints as well as the increased immune organ index within CFA-induced arthritic mice. Histopathological analysis showed that tectoridin alleviated the lesions of ankle joints and synovial tissues induced by CFA. Secretion of pro-inflammatory cytokines in TNF-α-induced HFLSs cells and CFA-stimulated arthritic mice were also abated by tectoridin. Similarly, the presence of tectoridin significantly inhibited the abnormal phosphorylation levels of ERK, JNK, and p38 in vivo and in vitro. All those results highlighted that tectoridin exhibits anti-arthritis effects by inhibiting MAPK-mediated inflammatory responses.

Tectoridin, isolated from the dry rhizome of iris, is a compound with multiple biological activities. However, its biological roles in rheumatoid arthritis (RA) have still not been clearly elucidated. The aim of this study was to focus on the effects of tectoridin on tumor necrosis factor (TNF)-α-induced human fibroblast‑like synoviocyte rheumatoid arthritis (HFLS‑RA) cells, and its associated mechanisms. After TNF-α stimulation, CCK8 and MTT assays, TUNEL assay and flow cytometry, Western blotting and immunohistochemistry analysis were performed to check the cell proliferation, cell apoptosis and cycle analysis, and the expression of related proteins, respectively. Our results showed that tectoridin significantly hindered cell proliferation, S-to-G2/M phase transition and down-regulated Cyclind 1 and PCNA protein levels. Additionally, tectoridin markedly promoted apoptosis rates of HFSL-RA cells and elevated the expression levels of Cleaved Caspase-3 and Bax, while reduced the expression level of Bcl-2. Moreover, tectoridin reversed TNF-α-induced overexpression of MMPs and factors associated with the TLR4/NLRP3/NF-κB pathway. We conclude that tectoridin ameliorated TNF-α-induced proliferation and inflammation by inhibiting TLR4/NLRP3/NF-κB pathway. It might provide a new insight for the clinical application of RA.

In the present work, NiCrAlCoY-Al gradient composite coatings were successfully fabricated on Ti-6Al-4V alloy substrate via high-energy mechanical alloying method. The microstructures and elemental and phase composition of the coatings have been studied. Effects of both NiCrAlCoY-Al powder ratio and milling time on the fabrication of composite coating were investigated. The NiCrAlCoY-Al weight ratio 65:35 was considered the optimal powder ratio to fabricate the coating at the selected milling parameters. The high-temperature cyclic oxidation tests were performed at 850 °C and 750 °C. The fabricated sample using 65:35 wt ratio and 4 h milling time showed the best oxidation resistance due to the low mass gain, rutile TiO 2 undetected surface, and densified composite cross-section morphology. The decreased oxygen content of the oxidized cross-section line scanning results revealed the improvement of oxidation resistance. The oxidation process of the as-fabricated coating had been divided into five steps. Three protective Al 2 O 3 oxide layers together with other alloy compounds could prevent the further diffusion of oxygen. The coating could enhance the oxidation resistance of the substrate.

Vascular smooth muscle cells (VSMCs) lesions play an important role in atherosclerosis. The latest findings indicate that green tea extract has potential benefits for patients with atherosclerosis, but the components and mechanisms of action are unknown. (−)-Epicatechin gallate (ECG) is the main active ingredient extracted from green tea and has significant biological functions. However, the mechanism of ECG in atherosclerosis remains unclear. Therefore, we investigated the intervention of ECG on VSMCs induced by oxidized low-density lipoprotein (ox-LDL). The results show that ECG reduces the inflammatory response by preventing the overproduction of inflammatory mediators in VSMCs. ECG regulates the cell cycle and down-regulates the expression of proliferating cell nuclear antigen (PCNA) and cyclinD1, and then exerts an anti-proliferative effect. Furthermore, inhibition of the expression of matrix metalloproteinase 2 (MMP-2) and intercellular adhesion molecule 1 (ICAM-1) may be the mechanism by which ECG inhibits the migration of ox-LDL-induced VSMCs. Oil red O staining results show that ECG can improve cell foaming and reduce the content of total cholesterol (TC). In addition, ECG significantly reduces reactive oxygen species activity and also reduces the expression of p-p38, p-JNK, p-ERK1/2, p-IκBα, p–NF–κBp65, and TLR4. These results indicate that ECG has potential clinical applications for preventing atherosclerosis.

(FeNiCoCrTi0.5)Cx (x = 3 wt%, 6 wt%, 12 wt%) carbonized high-entropy alloy-based composite coatings, marked as C3, C6 and C12, were prepared on 45 steel by laser cladding. The macroscopic morphology, phase, microstructure, hardness and wear resistance of coatings have been investigated systematically. The results indicate that diamond content has a significant influence on the microstructure and mechanical properties of (FeNiCoCrTi0.5)Cx coating. (FeNiCoCrTi0.5)Cx coatings, without pores and cracks, are well metallurgically bonded with substrate. The coatings consist of BCC solid solution, Cr23C6 and TiC. The addition of diamond in (FeNiCoCrTi0.5)Cx coating leads to the instability of BCC solid solution and facilitates the precipitation of carbides, which causes carbides to become coarse and aggregate into large blocks. The hardness of (FeNiCoCrTi0.5)Cx coatings is much higher than that of the 45 steel, the average hardness of C12 coating is 4 times the hardness of substrate. Besides, the hardness of (FeNiCoCrTi0.5)Cx coating increases with the increase of diamond content. Nonetheless, compared to C6 coating, the C12 coating shows inferior tribological performance due to the brittleness. It is noteworthy that C6 coating with outstanding wear resistance has the potential to apply in various fields of machinery industry, marine engineering and aerospace.

FexNi2Co2CrTiNb (x = 0, 0.5, 1, 2) high-entropy alloy coatings were fabricated on 45 steel by laser cladding. The phase, microstructure, hardness and wear resistance of FexNi2Co2CrTiNb coatings are studied systematically. The results behave that FexNi2Co2CrTiNb (x = 0, 0.5, 1, 2) coatings are composed of FCC and BCC solid solutions. When the Fe content increases from 0 to 2, the BCC phase in the coating increases significantly while the FCC phase decreases notably, the microstructure of FexNi2Co2CrTiNb coating evolves from coarse dendrites to the fine dendritic clusters in the general form of columnar or equiaxed crystals. The hardness of each FexNi2Co2CrTiNb (x = 0, 0.5, 1, 2) coating is much higher than that of the substrate. The highest hardness measured reaches up to 873.40 HV, which is about 3 times the hardness of the substrate. The average hardness of the FexNi2Co2CrTiNb coating presents an increasing trend with the increase of Fe content, the average hardness of Fe2Ni2Co2CrTiNb coating is 40.74 % higher than that of the Fe0Ni2Co2CrTiNb coating. Correspondingly, Fe2Ni2Co2CrTiNb coating with the highest hardness has the best wear resistance. The Fe2Ni2Co2CrTiNb coating with excellent wear resistance can be fully applied to various tools, molds and mechanical parts that require high hardness and superior wear resistance.

FeNiCoCrTi0.5Nbx (x = 0.25, 0.50, 0.75, 1.00) high-entropy alloy coatings are prepared by laser cladding. The phase, microstructure, hardness and wear resistance of each coating are analyzed. The results show that each coating has BCC, FCC and Laves phase and the content of Laves phase increases with the increase of Nb content. The microstructure of those coatings are obviously different with the change of Nb content. The top and bottom of each coating are composed of equiaxed crystals and columnar crystals with preferential orientation, respectively. While the middle part of coatings shows different forms of dendrites, equiaxed cellular dendrites and short strips structure. The hardness of each FeNiCoCrTi0.5Nbx coating is much higher than that of the substrate. FeNiCoCrTi0.5Nb0.5 coating has the highest average hardness of 766.62 HV. Furthermore, the highest hardness measured of FeNiCoCrTi0.5Nb0.5 coating reaches up to 852.5 HV, which is about 2.9 times the hardness of the matrix. Each FeNiCoCrTi0.5Nbx coating produces abrasive wear. The worn surface of FeNiCoCrTi0.5Nb0.5 coating is smoother, the degree of wear is lower and the corresponding wear rate is the lowest. The FeNiCoCrTi0.5Nb0.5 coating has the highest hardness and the best wear resistance.

To investigate the uniqueness of graphene, compared with graphite, in the preparation of TiC reinforced composite coating, the composite coatings were obtained from Ni-Cr-Ti-graphene/graphite powder by laser cladding. The phase composition and microstructure of composite coatings are detected by X-ray diffraction (XRD) and scanning electron microscope (SEM) with energy dispersive spectrometry (EDS), respectively. The phase composition of the composite coatings both mainly consist of Ni-Cr-Fe, Ni3Ti, Cr2Ti and TiC. The research results indicate that the crystal structures of in-situ synthesized TiC in the composite coatings have great difference, in detail, TiC crystals in the graphene-coating and the graphite-coating are dominated by equiaxed and dendrite crystals, severally, which is due to the reaction of two-dimensional graphene with Ti has better diffusion kinetics than that of three-dimensional graphite under rapid solidification of molten pool. The maximum microhardness of graphene-coating is 1000.3 HV0.1, which is about 4 times as hard as the substrate. The composite coatings show significant improvement in hardness and wear resistance than the substrate. The graphene-coating possesses more uniform hardness distribution and better wear resistance than that of graphite-coating, which is benefited from the uniform distribution of TiC equiaxed crystals in the graphene-coating.