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The (La0.5Eu0.25Y0.25)2Zr2O7 (LEYZ) ceramic powder for spraying was prepared and synthesised by combining spray granulation and solid phase reaction phase, and a double ceramic layer structure with (La0.5Eu0.25Y0.25)2Zr2O7 ceramic surface coating and YSZ intermediate coating was prepared by atmospheric plasma spraying. Experimental characterisation revealed that the moulding state of spray granulated powders was significantly influenced by the solid content. When the solid content is small, the viscosity of the slurry is insufficient, and the prepared powder has poor formability and small overall particle size. When the solid content is large, the slurry is too viscous, which easily leads to unfavourable conditions such as sticky walls. The best formability of the pelletised powder was obtained with a solid content of 55 wt-% and a binder content of 2.0 wt-%. Compared with La2Zr2O7 (LZ) ceramics, the fracture toughness of the rare-earth co-doped modified LEYZ ceramic coating was increased by 8.4% and the bond strength was increased by 49.9%, showing good toughness and crack resistance. Moreover, LEYZ coating has significantly better resistance to solid phase particle erosion than LZ coating, with 46.3% and 45.4% reduction in erosion rate at 45° and 90°, respectively. [ABSTRACT FROM AUTHOR]

Background: The intestinal microbiota is thought to be involved in the occurrence of inflammatory bowel disease in remission with irritable bowel syndrome (IBS)-type symptoms, but the specific distinct profile of these bacteria remains unclear. This cross-sectional study aims to investigate the fecal microbiota profiling in patients with these diseases.Methods: Fecal samples from 97 subjects, including Crohn's disease patients in remission with IBS-type symptoms (CDR-IBS+) or without IBS-type symptoms (CDR-IBS-), ulcerative colitis patients in remission with IBS-type symptoms (UCR-IBS+) or without IBS-type symptoms (UCR-IBS-), IBS patients and healthy controls, were collected and applied 16S ribosomal DNA (rDNA) gene sequencing. The V4 hypervariable regions of 16S rDNA gene were amplified and sequenced by the Illumina MiSeq platform. The differences in the sample diversity index in groups were analyzed with R software.Results: The richness of the intestinal microbiota in the CDR-IBS group was markedly lower than those in the control and IBS groups based on the analysis of observed species and the Chao index (P < 0.05). The observed species index in the CDR-IBS+ group was higher than that in the CDR-IBS- group (median index: 254.8 vs 203, P = 0.036). No difference was found in alpha diversity between UCR patients with IBS-type symptoms and those without related symptoms. At the genus level, the number of Faecalibacterium in CDR patients with IBS-type symptoms increased significantly, while Fusobacterium decreased versus those without such symptoms (mean relative abundance of Faecalibacterium: 20.35% vs 5.18%, P < 0.05; Fusobacterium: 1.51% vs 5.2%, P < 0.05). However, compared with the UCR-IBS- group, the number of Faecalibacterium in the UCR-IBS+ group decreased, while the number of Streptococcus increased, but there was no significant difference in the genus structure. The abundance and composition of the microbiota of IBS patients were not distinct from those of healthy controls.Conclusions: The IBS-type symptoms in CD patients in remission may be related to an increase in Faecalibacterium and a decrease in Fusobacterium. The IBS-type symptoms in UC patients in remission cannot be explained by changes in the abundance and structure of the intestinal microbiota. [ABSTRACT FROM AUTHOR]

The directional array TiN-reinforced AlCoCrCuNiTi high-entropy alloy (HEA) coating was designed and the correlative coating was successfully synthesized by magnetic-field-assisted laser cladding on Ti-6Al-4V (TC4) alloy. The effect of the directional array TiN on the phase structure, microstructure, microhardness and wear resistance of HEA coating were investigated methodically. As a result, the HEA coatings are mainly composed of body-centered-cubic solid solution phase, (Ni, Co)Ti2 inter metallic compound and TiN ceramic phase. With 1 T magnetic induction intensity assisted laser cladding, the microstructure of in-situ TiN displays a "cross" shape of the directional array. And the coating shows excellent wear resistance with an average microhardness of 760 HV. The worn surface morphologies of HEA coatings show that the wear mechanism is adhesive wear regardless of whether a magnetic field is added. This work can provide a novel and effective method to synthesize directional array microstructures to improve the performance of HEA coating, which will promote the further application of directional array microstructures in advanced manufacturing fields. [ABSTRACT FROM AUTHOR]

The excellent strength and hardness obtained from the customized phase compositions provide vast spaces for surface protection application of refractory high entropy alloy (RHEA) coatings in titanium alloys. However, the introduction of high-strength brittle phase in RHEA coatings commonly increases the cracking tendency and affects their service life. In this work, we propose a design strategy to enhance the mechanical properties of RHEA coatings by introducing an extremely stable high strength boride combined with a ductile phase. Experimentally, LaB 6 /NbNiTaTi RHEA coatings mainly consist of BCC phase, in-situ TaB phase and NiTi/IM eutectic phase. TaB phase with high-density (110) nanotwins inside presents needle-like morphology with the long side axis parallel to the [001] direction. Excessive needle-like TaB phase is fully fused and fractured due to its preferential growth along a specific direction. The fracture surface analysis shows that BCC phase bears the main deformation, NiTi phase can relieve stress concentration at the boundary while bearing a small amount of deformation. By contrast, the low-density dislocation distribution and the low energy extended dislocation structure in TaB phase exhibit the phase stability. In addition, the amorphous islands are formed near the high-deformation regions when the defect concentration reaches the critical value. [Display omitted] • TaB phase with high-density stacking faults was formed in situ. • The RHEA coatings exhibited superior compressive strength and ductility. • Different phases played different roles in the process of bearing deformation. • Grain boundary strengthening and dislocation strengthening were the main factors of strengthening mechanism. [ABSTRACT FROM AUTHOR]

The corrosion and wear requirements of Zr alloys for application as fuel cladding materials are becoming increasingly stringent. Accordingly, developing surface engineering techniques and high-performance coating materials is crucial for achieving improved surface properties of these alloys. Herein, we propose a strategy for preparing high-performance coatings on Zr alloys using the multilayer cladding technique to prevent the high dilution of Zr alloy substrates because of high-energy beams. A novel Al 0.2 NbTiV 0.1 W 0.5 Zr 0.3 high-entropy alloy (HEA) coating with a multilayer structure was prepared on a Zr alloy using multiple laser claddings. The top-layer and interlayer were composed of two body-centered cubic (BCC) phases and a Zr-rich phase. Owing to the multilayer cladding, the top-layer was almost unaffected by matrix dilution and substrate evaporation, leading to a significantly reduced precipitation of the Zr-rich phase in the top-layer. The high hardness and excellent wear resistance of the coating were attributed to the two BCC phases; moreover, both, the Zr-containing HEA and substrate, exhibited adhesive wear. The top-layer exhibited superior pitting corrosion properties, whereas the microstructural inhomogeneity in the interlayer led to intergranular corrosion, dominating the corrosion process. Thus, this study presents a coating material system suitable for Zr alloys with excellent wear and corrosion resistances. The findings can potentially contribute to expanding the application of the high-energy beam technology to Zr alloys. [Display omitted] • Al 0.2 NbTiV 0.1 W 0.5 Zr 0.3 HEA coating with multilayer structure was prepared on Zr alloy by multiple laser cladding. • The microstructure and properties of top-layer and interlayer on the multi-layer strategy were investigated. • The Zr-rich phase and two coexisting BCC phases are formed in the coating. • IGC dominates the corrosion process in the interlayer owing to microstructural inhomogeneity. • The corrosion and wear resistance of Zr alloy surface are significantly improved. [ABSTRACT FROM AUTHOR]

This work is aimed to explore ways to further improve corrosion properties of single-phase RHEA coating by introducing in-situ TiC phase. Results shown that C/Al 0.1 CrNbSi 0.1 TaTiV RHEA coatings exhibited better comprehensive resistance to pitting and general corrosion compared to most of reported HEAs and traditional alloys. The passive film was dominated by a muti-oxide crystalline structure with a thickness of ∼ 11.52 nm. The small-size and evenly distributed TiC phase with most thermodynamically stable could be obtained via doping C and retard the nearby pitting process, improving the pitting behavior and the dense of passive film in 1.0 wt% C coating. [Display omitted] • A small amount of in-situ TiC phase enhances the corrosion resistance of RHEA coatings. • The passive films show biphasic semiconductor behavior. • The passive film is a muti-oxide crystalline structure with a thickness of ∼ 11.52 nm. • Al, Si and Ta elements are the main component of passive films. [ABSTRACT FROM AUTHOR]

Multi-principal element alloy coatings (MPEACs) have great application potential for high-temperature diffusion barrier coatings. The sluggish diffusion and lattice distortion of this new coating material due to its own atomic size effect give the coating excellent resistance to high temperature oxidation and grain coarsening. In this study, the high-temperature oxidation properties, and microstructure evolution of quaternary, quinary, senary, and denary alloy coatings (whose lattice distortion magnitude is linearly increased) at 1100 °C were studied. The evolution of grain orientation, size, and grain boundaries of alloy coatings after high temperature exposure were analyzed by EBSD. The results showed that from quaternary to denary alloy coatings, with the rise in lattice distortion magnitude of the alloy system, the sluggish diffusion ability of the coating at high temperatures was more obvious. Specifically, the oxidative activation energy of quaternary to denary alloy coatings is 355.41, 480.96, 478.76, and 654.03 kJ/mol, respectively. A high distortion magnitude is beneficial to increase the activation energy of the alloy coating, as a result, grain growth of alloy coatings with high activation energy is significantly inhibited, and under the combined action of storage strain energy and solute dragging, the grain boundary migration rate of the coatings also declines. Finally, the denary alloy coating shows good resistance to high temperature softening. This study provides a positive reference for promoting the application of multi-principal alloys in diffusion barrier coatings. • High-temperature oxidation and microstructure evolution of quaternary, quinary, senary, and denary alloy coatings at 1100 °C were studied. • The oxidative activation energy increases linearly from quaternary to denary alloy coatings. • The grain growth of the coating gradually weakened from quaternary to denary alloy coatings. • Grain boundary migration rates are affected by the combined effects of storage strain energy and solute dragging. • The denary alloy coating shows good resistance to high-temperature softening. [ABSTRACT FROM AUTHOR]

It is challenging to obtain the underwater wet laser cladding layer with excellent properties while maintaining formability. In this paper, the method of using synchronous mechanical vibration assisted in the underwater wet laser cladding process of TiN/Fe-based cladding layer was introduced. The effect of mechanical vibration frequency on the dilution rate, microstructure, corrosion resistance, tribo-corrosion behavior of the cladding layer was studied. The result displayed that with increase of mechanical vibration frequency, the dilution effect of the substrate was obviously weakened and the phase changed from ferrite to ferrite and austenite, and TiN particles were evenly distributed. In addition, the grain size of the cladding layer showed a tendency to decrease first and then increase. When the mechanical vibration frequency was 400 Hz, the grain refinement phenomenon was the most obvious and the average grain size was 8.39 μm. Based on the effect of dispersion strengthening and fine grain strengthening, the microhardness and wear resistance of the cladding layer assisted at 400 Hz were improved, and the wear rate was 1.17 × 10−15m3N−1 m−1. While the cladding layer assisted at 400 Hz exhibited better corrosion resistance by forming a dense passivation film. In addition, the mechanism of mechanical vibration on microstructure evolution and performance enhancement of the cladding layer was also analyzed. This study provided the theoretical support for the formability of the underwater laser wet cladding assisted by mechanical vibration. • The TiN/Fe-based underwater wet cladding layer was successfully prepared assisted with mechanical vibration. • Action mechanism of mechanical vibration on TiN/Fe-based underwater wet cladding layer is explained. • The grain refinement mechanism of TiN/Fe-based underwater wet cladding layer is proposed. • Dispersion strengthening and grain refining strengthening are the main strengthening mechanisms. [ABSTRACT FROM AUTHOR]

High prevalence of vitamin D deficiency has been found among Crohn's disease (CD) patients. Vitamin D probably participates in the pathogenesis of CD, but this idea remains controversial. This study was to investigate the levels of vitamin D in CD patients and analyze the relationship between vitamin D and intestinal inflammation. Vitamin D levels were measured by chemiluminescence immunoassay in 198 CD patients (96 in active, 102 in remission) and 100 healthy controls. The correlation between vitamin D levels and clinical parameters was analysed. The expression of intestinal tight junction (TJ) proteins in CD patients was measured by immunofluorescence staining. Treg and Th17 percentages in the peripheral blood were determined by flow cytometry. CD patients exhibited significantly lower 25(OH)D levels than healthy controls, especially in active CD patients. Serum 25(OH)D levels in CD patients were negatively correlated with the CD activity index (CDAI), the simple endoscopic score for CD (SES-CD), and inflammatory markers, including erythrocyte sedimentation rate (ESR), platelet (PLT) count and faecal calprotectin (FC) levels. Moreover, in patients with vitamin D deficiency, the expression of TJ proteins (Occludin, claudin-1, ZO-1 and JAM-1) in the intestinal mucosa was reduced, and Treg cells in the peripheral blood were decreased, while Th17 cells were increased compared to those with vitamin D sufficiency and controls. Vitamin D deficiency in CD patients is common. Vitamin D is associated with disease activity and intestinal inflammation, which may affect the Treg/Th17 balance and the expression of gut TJ proteins. [ABSTRACT FROM AUTHOR]

Growing evidence suggested that microRNAs (miRNAs) contributed to the progression of Crohn's disease (CD), but the exact physiological functions of many miRNAs in CD patients still remain illusive. In this study, we explore the potent pathogenicity of miRNAs in CD. Expressions of miRNAs and aryl hydrocarbon receptor (AHR) protein were determined in the colitic colon of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis mice and CD patients. Colitis was induced in wild-type (WT), miR-124a overexpression (miR-124a-Nju), and AHR knockout (AHR−/−) mice. Intestinal barrier function was evaluated in colitis mice and Caco2 monolayers. There was a negative relationship between miR-124a and AHR protein in inflamed colons from CD patients. MiR-124a-Nju and AHR−/− mice treated with TNBS had more severe intestinal inflammation than WT mice. Both miR-124a-Nju mice and AHR−/− mice underwent evident intestinal barrier destruction, and anti-miR-124a administration could reverse this dysfunction in miR-124a-Nju mice but not in AHR−/− mice. In vitro studies revealed that miR-124a mimics downregulated the expression of AHR and tight junction proteins and induced hyperpermeability by increasing miR-124a expression, which was abrogated by miR-124a inhibitor and AHR antagonist FICZ. This study suggests that miR-124a can induce intestinal inflammation and cause intestinal barrier dysfunction by supressing AHR. [ABSTRACT FROM AUTHOR]