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Thermal spraying is one of the most important approaches for depositing thermally insulating ceramic top coatings for advanced gas turbines due to the low thermal conductivity of the coating resulting from its lamellar structure. The thermal conductivity of the coating has been explained based on the concept of thermal contact resistance and correlated to microstructural aspects such as splat bonding ratio, splat thickness, and the size of the bonded areas. However, the effect of intrasplat cracks on the thermal conductivity was usually neglected, despite the fact that intrasplat cracking is an intrinsic characteristic of thermally sprayed ceramic coatings. In this study, a model for the thermal conductivity of a thermally sprayed coating taking account of the effect of intrasplat cracks besides intersplat thermal contact resistance is proposed for further understanding of the thermal conduction behavior of thermally sprayed coatings. The effect of the intersplat bonding ratio on the thermal conductivity of the coating is examined by using the model. Results show that intrasplat cracks significantly decrease the thermal conductivity by cutting off some heat flux paths within individual splats. This leads to a deviation from the typical ideal thermal contact resistance model which presents cylindrical symmetry. Based on the modified model proposed in this study, the contribution of intrasplat cracks to the thermal resistivity can be estimated to be 42–57 % for a typical thermally sprayed ceramic coating. The results provide an additional approach to tailor the thermal conductivity of thermally sprayed coatings by controlling the coating microstructure. [ABSTRACT FROM AUTHOR]

[Display omitted] • It is the first study to identify the effects of MSC-sEV on steroid-resistant and Th17-dominant allergic airway inflammation. • MSC sEV regulated Th17 polarization via JAK-STAT3 signaling pathways in allergic inflammation • Proteins but not RNAs in MSC-sEV were involved in the effects of MSC-sEV. Type 17 helper T cells (Th17)-dominant neutrophilic airway inflammation is critical in the pathogenesis of steroid-resistant airway inflammation such as severe asthma. Small extracellular vesicles (sEV) derived from human mesenchymal stem cells (MSCs) display extensive therapeutic effects and advantages in many diseases. However, the role of MSC-sEV in Th17-dominant neutrophilic airway inflammation and the related mechanisms are still poorly studied. Here we found that MSC-sEV significantly alleviated the infiltration of inflammatory cells in peribronchial interstitial tissues and reduced levels of inflammatory cells, especially neutrophils, in bronchoalveolar lavage fluids (BALF) of mice with neutrophilic airway inflammation. Consistently, MSC-sEV significantly decreased levels of IL-17A in BALF and Th17 in lung tissues. Furthermore, we found that labelled MSC-sEV were taken up by human CD4+ T cells most obviously at 12 h after incubation, and distributed mostly in mouse lungs. More importantly, potential signaling pathways involved in the MSC-sEV mediated inhibition of Th17 polarization were found using RNA sequencing. Using Western blot, JAK2-STAT3 pathway was identified as an important role in the inhibition of Th17 polarization by MSC-sEV. We found that proteins in MSC-sEV were mostly involved in the therapeutic effects of MSC-sEV. In total, our study suggested that MSC-sEV could be a potential therapeutic strategy for the treatment of neutrophilic airway inflammation. [ABSTRACT FROM AUTHOR]

This article examines the association between daily levels of ambient air pollution and hospital visits for allergic diseases. Previous studies have typically used population-average exposure data, which may lead to biased effect estimates. In this study, individual exposure data was used to assess the effects of ambient air pollution on outpatient visits for allergic diseases. The results showed that increases in fine particulate matter (PM2.5) and ozone (O3) were associated with an increased risk of allergic diseases. Additionally, population-average exposure to PM2.5, particulate matter (PM10), O3, and sulphur dioxide (SO2) were also associated with an increased risk of allergic diseases. The study highlights the adverse effects of air pollution on allergic diseases and supports efforts to mitigate pollution and protect vulnerable individuals. [Extracted from the article]

Backgrounds: Allergic airway inflammation is prevalent worldwide and imposes a considerable burden on both society and affected individuals. This study aimed to investigate the therapeutic advantages of mesenchymal stem cells (MSCs) overexpressed interleukin-10 (IL-10) for the treatment of allergic airway inflammation, as both IL-10 and MSCs possess immunosuppressive properties. Methods: Induced pluripotent stem cell (iPSC)-derived MSCs were engineered to overexpress IL-10 via lentiviral transfection (designated as IL-10-MSCs). MSCs and IL-10-MSCs were administered intravenously to mice with allergic inflammation induced by ovalbumin (OVA), and the features of allergic inflammation including inflammatory cell infiltration, Th cells in the lungs, and T helper 2 cell (Th2) cytokine levels in bronchoalveolar lavage fluid (BALF) were examined. MSCs and IL-10-MSCs were co-cultured with CD4+ T cells from patients with allergic rhinitis (AR), and the levels of Th2 cells and corresponding type 2 cytokines were studied. RNA-sequence was performed to further investigate the potential effects of MSCs and IL-10-MSCs on CD4+ T cells. Results: Stable IL-10-MSCs were established and characterised by high IL-10 expression. IL-10-MSCs significantly reduced inflammatory cell infiltration and epithelial goblet cell numbers in the lung tissues of mice with allergic airway inflammation. Inflammatory cell and cytokine levels in BALF also decreased after the administration of IL-10-MSCs. Moreover, IL-10-MSCs showed a stronger capacity to inhibit the levels of Th2 after co-cultured with CD4+ T cells from patients with AR. Furthermore, we elucidated lower levels of IL-5 and IL-13 in IL-10-MSCs treated CD4+ T cells, and blockade of IL-10 significantly reversed the inhibitory effects of IL-10-MSCs. We also reported the mRNA profiles of CD4+ T cells treated with IL-10-MSCs and MSCs, in which IL-10 played an important role. Conclusion: IL-10-MSCs showed positive effects in the treatment of allergic airway inflammation, providing solid support for the use of genetically engineered MSCs as a potential novel therapy for allergic airway inflammation. [ABSTRACT FROM AUTHOR]

• Three Ni powders were sprayed on AZ31B by cold spray for corrosion protection. • Coating microstructures and corrosion performances were correlated with powder feature. • Powder surface protruding granules will hinder inter-particle intimate contact. • The gas-atomized smooth Ni powder can give > 3000 h corrosion protection for AZ31B. Three nickel (Ni) powders, i.e. gas-atomized spherical Ni (GA-Ni), carbonyl irregular Ni (C-Ni), and electrolytic dendritic porous Ni (E-Ni), were sprayed on magnesium alloys by an in-situ micro-forging assisted cold spray method. Although all deposited coatings present extremely low porosity, the C-Ni and E-Ni coatings reveal poorer inter-particle bonding than GA-Ni coating. Electrochemical tests reveal that the inter-particle gaps will act as fast pathways for the corrosive media to penetrate the coatings, thereby the GA-Ni coating with intimate inter-particle boundaries can isolate the corrosive media for 3000 h and the C-Ni and E-Ni coatings fail after <10 h corrosion. [ABSTRACT FROM AUTHOR]

The radiative energy loss accounts for roughly 70% of the energy loss in the polysilicon chemical vapor deposition (CVD) reactors and therefore takes up to about 25% cost in the production of polysilicon used for solar cells. In this work, cold spray (CS) process was used to deposit Ag coating with ultra-high infrared reflectance on inner wall of the CVD reactor to minimize the radiative losses. To solve the bond strength problem of depositing soft coatings on hard substrate by CS, a Ni buffer layer with medium hardness was introduced. Results show that Ag coating can be successfully deposited with a porosity lower than 0.1%. Even the as-sprayed Ag coating has a high near-infrared reflectivity of 92% which was much higher than that of a well-polished substrate surface (65%) suggesting an excellent radiation energy saving capacity. The bond strength of the Ag coating is significantly increased from 3.7 MPa to 35.4 MPa and the thermal shock resistance is improved from 22 ± 3 to over 150 cycles by the Ni buffer layer. The scientific methodology demonstrated here can be a cost effective approach to reduce the radiation energy losses in the polysilicon-CVD industry. Unlabelled Image • Ag coating was cold sprayed on polysilicon CVD reactor wall for radiation energy saving. • A high near infrared reflectivity of 99.3% was achieved indicating 17 kWh/kg energy saving. • adhesion and thermal shock resistance was improved by several folds by the Ni buffer layer. • An economic radiation saving method was provided for polysilicon production. [ABSTRACT FROM AUTHOR]