46 research outputs found

    High-strong-ductile magnesium alloys by interactions of nanoscale quasi-long period stacking order unit with twin.

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    Magnesium alloys with high strength in combination of good ductility are especially desirable for applications in transportation, aerospace and bio-implants owing to their high stiffness, abundant raw materials, and environmental friendliness. However, the majority of traditional strengthening approaches including grain refining and precipitate strengthening can usually prohibit dislocation movement at the expense of ductility invariably. Herein, we report an effective strategy for simultaneously enhancing yield strength (205 MPa, 2.41 times) and elongation (23%, 1.54 times) in a Mg-0.2Zn-0.6Y (at.%) alloy at room temperature, based on the formation of a nanosized quasi-long period stacking order unit (QLPSO)-twin structure by ultrahigh-pressure treatment followed by annealing. The formation reason and strong-ductile mechanism of the unique QLPSO-twin structure have been clarified by transmission electron microscopy observations and molecule dynamics simulations. The improved strength is mainly associated with the presence of nanosized QLPSO and the modified <86.3o QLPSO-twin boundary (TB) interface, effectively pinning dislocation movement. Comparatively, the enhanced ductility is related to the <3.7o QLPSO-TB interface and micro-kinks of nanoscale QLPSO, providing some paths for plastic deformation. This strategy on the QLPSO-twin structure might provide an alternative perspective for designing innovative hexagonal close-packed structural materials with superior mechanical properties

    Ni/SiO2 Catalyst Prepared with Nickel Nitrate Precursor for Combination of CO2 Reforming and Partial Oxidation of Methane: Characterization and Deactivation Mechanism Investigation

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    The performance of Ni/SiO2 catalyst in the process of combination of CO2 reforming and partial oxidation of methane to produce syngas was studied. The Ni/SiO2 catalysts were prepared by using incipient wetness impregnation method with nickel nitrate as a precursor and characterized by FT-IR, TG-DTA, UV-Raman, XRD, TEM, and H2-TPR. The metal nickel particles with the average size of 37.5 nm were highly dispersed over the catalyst, while the interaction between nickel particles and SiO2 support is relatively weak. The weak NiO-SiO2 interaction disappeared after repeating oxidation-reduction-oxidation in the fluidized bed reactor at 700°C, which resulted in the sintering of metal nickel particles. As a result, a rapid deactivation of the Ni/SiO2 catalysts was observed in 2.5 h reaction on stream

    Nutrient sequestration from wastewater by using zeolite Na-P1 synthesized from coal fly ash

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    <p>The objective of this study is to investigate the cation exchange property of the product zeolite Na-P1 (Z-P1) synthesized from coal fly ash (FA) by the alkali hydrothermal reaction, and to evaluate the water purification ability for the simultaneous removal of ammonium and phosphate. High-purity Z-P1 was obtained by optimizing the reaction conditions of aging time and crystallization temperature, and using FA particles of uniform particle size. Kinetic ammonium sorption experiments with Z-P1 were well described by both the Langmuir and Freundlich models, and the maximum adsorption capacity of the Z-P1 was 23.15 mg/g. Moreover, in order to determine the effect of magnesium intervention on the ammonium and phosphate removal from simulated swine wastewater, two forms of magnesium were studied, that is Mg-saturated Z-P1 and direct use of Mg<sup>2+</sup> source with Z-P1, as compared with the control (sole Z-P1). Results showed that Mg<sup>2+</sup> addition could improve phosphate removal efficiency significantly by forming struvite. Furthermore, dosing Z-P1 with dissolved Mg<sup>2+</sup> was better than Mg-saturated Z-P1 in terms of ammonium and phosphate removal efficiencies, and the preparation cost. When dosing 20 g/L Z-P1 with 4 mM Mg<sup>2+</sup>, ammonium and phosphate removal efficiencies reached 65.2% and 92.3% after 30 min.</p

    Polymorphisms at rs368698783 and rs7482144 loci in the promoter region of the HBG gene are associated with HbF expression

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    Objective To investigate the correlation between rs368698783 and rs7482144 locus and fetal hemoglobin (HbF) expression in β-thalassemia patients of Yunan province. Methods A total of 579 samples were collected, including 51 samples of β-thalassaemia, 40 samples with HbE, 113 samples of HbF>5%(βN/βN), 113 samples of HbF>5%(βM/βN) and 262 samples from controls. Sanger sequencing was used to determine the genotypes of rs368698783 and rs7482144. The relationship between rs368698783 and HbF levels was analysed by comparing haematological parameters, mutant gene detection rates and MAF. Results The detection rate and MAF of mutated genes at the rs368698783 and rs7482144 loci were significantly higher in non-transfusion-dependent β-thalassaemia patients than that in controls(P<0.05). The detection rate and MAF of mutated genes at the rs368698783 and rs7482144 loci were significantly higher in HbE pure samples than that in controls (P<0.001). The detection rates of mutated genes and MAF at rs368698783 and rs7482144 loci were significantly higher in HbF>5% (βN/βN) and HbF>5% (βM/βN) samples than in the control group (P<0.001). Conclusions The rs368698783 and rs7482144 mutation is associated with elevated HbF level and with HbE mutations. The A allele and T allele can reduce the degree of anaemia and alleviate the clinical symptoms of β-thalassemia

    Relation of Tea Ingestion to Salivary Redox and Flow Rate in Healthy Subjects

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    The biochemistry of human saliva can be altered by food intake. The benefits of tea drinking were extensively studied but the influence of tea ingestion on human saliva has not been revealed. The work aimed to investigate the immediate and delayed effect of vine tea, oolong tea and black tea intake on certain salivary biochemistry and flow rate. The saliva samples of healthy subjects were collected before, after and 30 min after tea ingestion. The chemical compositions and antioxidant capacity of tea samples were analyzed to correlate with salivary parameters. Principal component analysis indicated that the effects of vine tea consumption were dominated by increasing salivary flow rate (SFR), production rate of total protein (TPC), thiol (SH), malondialdehyde, catalase activity and antioxidant capacity (FRAP) in saliva. The antioxidant profile of studied tea samples (FRAP, polyphenols, flavonoids) was positively correlated with salivary SFR, TPC, SH and FRAP but negatively correlated with salivary uric acid concentration in saliva

    Chimonanthus nitens Oliv. leaves flavonoids alleviate hyperuricemia by regulating uric acid metabolism and intestinal homeostasis in mice

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    This study aimed to evaluate the alleviating effect of Chimonanthus nitens Oliv. leaves flavonoids (CLF) on hyperuricemia induced by potassium oxonate in mice. The results showed that CLF lowered the serum levels of uric acid (UA), creatinine and blood urea nitrogen, downregulated hepatic mRNA expressions of xanthine oxidase (XO), phosphate ribose pyrophosphate synthetase (PRPS) and adenosine deaminase (ADA) in hyperuricemia mice. In addition, CLF repaired renal injury by significantly down-regulating mRNA and protein expressions of renal UA reabsorption-related proteins and up-regulating the mRNA and protein expressions of UA secretory-related proteins. Finally, CLF inhibited UA synthesis and promoted UA excretion to alleviate hyperuricemia. Besides, CLF supplementation repaired the intestinal barrier function as demonstrated by significant increased mRNA levels of intestinal zonula occludens-1 (ZO-1), Occludin, mucin 2 (MUC2) and mucin 4 (MUC4), as well as decreased mRNA levels of toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88) in mice. Further research showed that CLF treatment restored intestinal homeostasis mediated by improving the composition of gut microbiota and elevating the abundance of beneficial bacteria like Lactobacillus, Alistipes, Prevotellaceae_UCG-001 and Parasutterella. Overall, our findings revealed a novel function of CLF as a promising therapeutic candidate for the treatment of hyperuricemia

    Diva acts through the intrinsic mitochondrial death pathway. a

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    <p>PC12 cells were harvested for total RNA isolation and quantitative real-time PCR to determine the changes in mRNA expression levels of Diva, Bcl2 and Bax following 100 ng/ml of FasL treatment. RNA was extracted 0 hr, 8 hrs, 24 hrs and 48 hrs after treatment and the fold changes were calculated with GAPDH as the internal control. <b>b</b> Fold changes of Diva and Bcl2 after addition of 30 nM of H<sub>2</sub>O<sub>2</sub> for 0 hrs, 2 hrs, 4 hrs and 8 hrs. <b>c</b> Fold change of Bax after 30 nM of H<sub>2</sub>O<sub>2</sub> treatment across 8 hrs. Bar graphs represent mean ± SD from three independent experiments. *p<0.05, **p<0.01. <b>d</b> PC12 cells were harvested to determine the protein expression levels of Diva, Cleaved Caspase 8, Bax, Bcl2 and Cleaved Caspase 3. Western blot was conducted on the total protein extracted following 100 ng/ml of FasL treatment for 0 hrs, 8 hrs, 24 hrs and 48 hrs. <b>e</b> PC12 cells were harvested to determine the protein expression levels of Diva, Cleaved Caspase 9, Bax, Bcl2 and Cleaved Caspase 3. Western blot was conducted on the total protein extracted following 30 nM of H<sub>2</sub>O<sub>2</sub> treatment for 0 hrs, 2 hrs, 4 hrs and 8 hrs. B-actin was used as the loading control.</p

    Total Flavonoids from <i>Chimonanthus nitens</i> Oliv. Leaves Ameliorate HFD-Induced NAFLD by Regulating the Gut–Liver Axis in Mice

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    Non-alcoholic fatty liver disease (NAFLD) is one of the chronic liver diseases with high incidence in the world. This study aimed to investigate whether total flavonoids from Chimonanthus nitens Oliv. leaves (TFC) can ameliorate NAFLD. Herein, a high-fat diet (HFD)-induced NAFLD mice model was established, and TFC was administered orally. The results showed that TFC reduced the body weight and liver index and decreased the serum and hepatic levels of triglyceride (TG) and total cholesterol (TC). TFC significantly reduced the activity of liver functional transaminase. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) decreased by 34.61% and 39.57% in serum and 22.46% and 40.86% in the liver, respectively. TFC regulated the activities of oxidative-stress-related enzymes and upregulated the protein expression of nuclear factor E2-related factor (Nrf2)/heme oxygenase (HO-1) pathway in NAFLD mice, and the activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-PX) in serum were increased by 89.76% and 141.77%, respectively. In addition, TFC reduced the levels of free fatty acids (FFA), endotoxin (ET), and related inflammatory factors in mouse liver tissue and downregulated the expression of proteins associated with inflammatory pathways. After TFC treatment, the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1β in the liver tissues of NAFLD mice were downregulated by 67.10%, 66.56%, and 61.45%, respectively. Finally, TFC reduced liver fat deposition, oxidative stress, and inflammatory response to repair liver damage and alleviate NAFLD. Further studies showed that TFC regulated the expression of intestinal-barrier-related genes and improved the composition of gut microbiota. Therefore, TFC reduced liver inflammation and restored intestinal homeostasis by regulating the gut–liver axis. Overall, our findings revealed a novel function of TFC as a promising prophylactic for the treatment of NAFLD
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