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Twenty-five per- and polyfluoroalkyl substances (PFASs) were analyzed in water, sediment and biota from the Dongshan Bay (DSB) to study their seasonal variations, composition profiles, potential pollution sources, partitioning behavior and risk assessments. The total concentrations of PFASs (∑PFASs) in water ranged from 3.2 to 6.5 ng L−1 (mean 4.0 ng L−1) during the dry season, and 0.11–4.5 ng L−1 (mean 1.3 ng L−1) during the wet season. Perfluoro-butane sulfonic acid (PFBS), perfluoro-butanoic acid (PFBA) and perfluoro-octanoic acid (PFOA) were dominated and frequently detected in water. ∑PFASs in sediment were 0.15–0.37 ng g−1 dw (mean 0.24 ng g−1 dw) with the long-chain PFASs perfluoro-octane sulfonic acid (PFOS) dominating. High concentrations of PFASs in land-based drainage outlets (2.0–384.6 ng L−1 in water) and Zhangjiang estuary indicated that land-based discharges and the river discharge were the main sources. High concentration (366.1 ng L−1) and proportion (94%) of PFBA on one drainage outlet agreed with the trend that PFBA was as an alternative to long-chain PFASs. ∑PFASs in biota ranged from 0.11 to 0.40 ng g−1 ww, and only long-chain PFASs were detected. The partition coefficients (log K d) of PFASs between water and sediment ranged from 1.13 to 2.90, increased with carbon chain length, implied long-chain PFASs are more likely to adsorb to sediment. Results of ecological and health risk assessments indicated that PFASs had no significant risk for the aquatic organisms and local residents. • Short-chain PFASs as alternatives increase in the environment. • Drainage outlets and the river discharge contributed PFASs to the DSB. • Log K d of PFASs increased with the increasing of carbon chain length. [ABSTRACT FROM AUTHOR]

Gestational Diabetes Mellitus (GDM) has an effect on the health of pregnant women and fetuses. Procyanidins (PA) is a flavonoid with anti-diabetic activity, but its effects and mechanisms on GDM have not been defined. Herein, we studied further the functions and mechanisms of PA on insulin resistance (IR) in GDM mice, as well as on postpartum and offspring mice. GDM mice model was built by feeding a high-fat-high-sucrose diet, and PA intervention (27.8 mg/kg/d) was performed from 4 weeks before pregnancy to delivery. Intestinal flora deficient (IFD) mice model was established by broad spectrum antibiotics. PA decreased the gestational weight gain, and the levels of fasting blood glucose, insulin, homeostasis model of assessment for IR index, yet increased the levels of HOMA for insulin sensitivity index. Interestingly, in IFD mice the effect of PA on improving IR was significantly weakened. PA inhibited inflammation by decreasing the levels of IL-6, TNF-α, IL-17 and CRP, which also been blocked in the IFD mice. Moreover, PA improved glycometabolism and reduced the secretion of inflammatory factors and hepatic inflammation infiltration of mice at 4 weeks postpartum, but had no significant effect on offspring mice. Mechanistically, PA treatment suppressed the nuclear factor‐κB (NF‐κB) p65 nuclear translocation and nucleotide‐binding domain like receptor protein 3 (NLRP3) inflammasome activation. In vitro studies, 4-hydroxyphenylacetic acid and 3-(4-hydroxyphenyl) propionic acid, main intestinal flora metabolites of PA restrained NF‐κB/NLRP3 activation. In conclusions, PA improved IR via NF-κB/NLRP3 pathway in GDM and postpartum mice, which partly through its metabolites by gut microbiome. [Display omitted] • Procyanidins alleviates IR and inflammation in GDM mice model. • Procyanidins improves the glycometabolism and reduces the secretion of inflammatory factors of postpartum mice with GDM. • Procyanidins inhibits IR via the NF-κB/NLRP3 signaling pathway, which is partly through its metabolites by gut microbiome. • 4-HPAA and HPPA, main gut metabolites of procyanidins blocked NF-κB/NLRP3 activation in RAW264.7 cells. [ABSTRACT FROM AUTHOR]

Based on the ultrasonic C-scan results of 8YSZ coatings after thermal cycles, three-dimensional cylindrical numerical simulations of the physical geometry model of the thermal barrier coating (TBC) sinusoidal surfaces were conducted with finite elements to estimate the stress distribution and evolution law of the top coat (TC)/bond coat (BC) interface, including the centre and edge of the specimen affected by the dynamic growth of the thermally grown oxide (TGO). The results show that when a layer of TGO is grown on the TC/BC interface, compressive stress is uniformly distributed on the TGO interface, and the stress value decreases as a function of the TGO layer thickness. When the thickness of the TGO exceeds a certain value, the compressive stress of all parts of the interface gradually changes to tensile stress; meanwhile, the edges of the model affected by the crest and trough effects of the wave are reflected in the radial and circumferential directions, especially along the axial direction, with alternating concentrated tensile and compressive stresses. TGO growth imposes a minor influence on the magnitude and distributions of the radial and circumferential stresses at the BC interface. The linear elasticity, creep, fatigue, and stress accumulation effects of each layer of TBCs in each thermal cycle were fully considered in this model. The model not only interprets the crest and trough effects of the TC/BC surface interface during the growth of TGO, but also interprets the effects of the core and edge of the cylindrical model, further revealing the reason for which the core and edge of the TBC will most likely form cracks. [ABSTRACT FROM AUTHOR]

A three-dimensional cylindrical numerical simulation physical and geometric model of TBCs sinusoidal surface was established based on the ultrasonic C-scan results of 8YSZ coating after thermal cycling. The stress distribution and evolution law of the TGO/BC interface and sample center and edge affected by TGO growth were simulated by the finite-element method. The results show that the stress at the TGO/BC interfaces changes from compressive stress to tensile stress with the increase of the number of thermal cycles. The center of the interface is distributed with large radial, circumferential and axial tensile stresses, while the edge of the sample is affected by thermal mismatch, which shows that shear stresses are alternately distributed in the XZ direction. The tensile stress at the center and the shear stress at the edge are the main reasons for the failure of the core and edge flakes of the thermal barrier coating. The linear elasticity, creep effect, fatigue effect and stress accumulation effect of each layer of TBCs in each thermal cycle period are fully considered by the model, which reveals the reason why the core and edges of the thermal barrier coating are most likely to form cracks. [ABSTRACT FROM AUTHOR]

A physical geometric model of the dynamic growth of thermally grown oxide (TGO) was established based on an analysis of the TGO growth of 8YSZ thermal barrier coatings during thermal cycling. Finite-element simulation was used to simulate the evolution law between the coating residual stress and thermal cycling, and the linear elasticity, creep effect, and stress accumulation in each thermal cycle were studied. The interface between the top coat (TC) and the bond coat (BC) was covered with a TGO layer that grew vertically and slowly in a layer-like manner. The stress in the TGO was distributed with a "layer" zonal gradient, and the TGO/BC boundaries were distributed uniformly with a large compressive stress, which decreased the TGO layer thickening. With the longitudinal rapid random TGO growth, the boundaries were subjected to a tensile stress, and a high tensile stress concentration area developed at the boundaries. The internal stress consisted of an alternating and mixed distribution of concentrated compressive and tensile stresses. The concentration area of the maximum equivalent stress was distributed in the one-layer TGO near the TC/TGO interface. When a microcrack formed at the TGO/BC boundaries, the crack was subjected to a tensile stress of different size, with a higher tensile stress at both ends, which facilitated crack expansion. Thus, the 8YSZ thermal barrier coating was prone to crack formation and expansion at the TGO/BC boundaries and in the TGO layer near the TC/TGO boundaries. [ABSTRACT FROM AUTHOR]

Perfluoroalkyl substances (PFAS) in water, sediment and fish were analyzed from a subtropical river, Jiulong River in the southeast of China, to character the sources, seasonal variations, bioconcentration and potential risk. PFAS in water, sediment, muscle and liver tissues of fish ranged from 2.5 to 410 ng L−1, 0.24–1.9 ng g−1 dw, 25–100 and 35–1100 ng g−1 ww, respectively. Generally, perfluorohexanoic acid (PFHxA) was the dominant compound in water, while, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were the dominant compounds in sediment and fish tissues. High concentrations of PFAS in water were found near the machinery manufacturing and paper packaging plants in the north branch of Jiulong River. PFAS during the dry season were significantly (P < 0.01) higher than that during the normal season and wet season. The K d of PFAS increased with the carbon chain length, and perfluoroalkyl sulfonic acids (PFSAs) exhibited higher K d values than perfluoroalkyl carboxylic acids (PFCAs), indicating these long chain PFAS tended to be adsorbed by sediment. Long chain PFAS exhibited high bioconcentration factors (BCFs), while short and medium carbon chain PFAS had weak bioconcentration capacity. The hazard ratios (HR) suggested that frequent consumption of river fish may pose health risks to local population. [Display omitted] • PFAS exhibited different composition profiles in water, sediment and fish. • Industrial activities contributed PFAS to the Jiulong River. • Carbon chain length and functional groups affected K d values. • PFAS tended to accumulate in the liver of fish. [ABSTRACT FROM AUTHOR]

The high-entropy metallic glasses (HEMGs), combining the characteristics of high-entropy alloys (HEAs) and metallic glasses (MGs), have recently appeared and become the research focus, due to their good glass-forming ability and high strength. However, the application of HEMGs as structural material is restricted owing to the limited tensile plasticity and absence of dislocation-dominated deformation mechanism. To resolve this pressing issue, a stable β-phase HEMG composite (β-type HEMGC) Ti 20 Zr 20 Hf 20 Nb 16 Co 5 Be 19 composed of the bcc refractory HEA (RHEA) dendrites and the HEMG matrix was fabricated. Ti 20 Zr 20 Hf 20 Nb 16 Co 5 Be 19 not only exhibits good tensile ductility, but also has the improved work-hardening capability under room temperature tension. Essentially, the dislocation-dominated deformation mechanism plays a significant role in achieving the excellent combination of good tensile plasticity and improved work-hardening capability of the stable β-type HEMGC. The tensile ductility of Ti 20 Zr 20 Hf 20 Nb 16 Co 5 Be 19 is attributed to the dislocation-slip mechanism induced by high-stable HEA dendrites, and the dislocation pile-up phenomenon has a great influence on the improved work-hardening capability of composite. The present results provide an indepth understanding of the deformation behavior of stable β-type HEMGCs, and a reference for how to improve the strength-ductility combination of HEMG-matrix composites. • By introducing bcc high-entropy alloy (HEA) into metallic glass matrix, the mechanical properties of high-entropy metallic glass composite (HEMGC) is effectively improved. • The tensile ductility of HEMGC is attributed to the dislocation-slip mechanism induced by high-stable HEA dendrites. • The dislocation pile-up phenomenon significantly improves the strength and work-hardening capability of HEMGC. [ABSTRACT FROM AUTHOR]