The optimization method of wing plasma ice shape regulation based on quantitative assessment of flight risk.

Plasma ice shape regulation is a technology which uses plasma actuator to regulate the continuous ice into safer intermittent ice by its significant thermal effect with limited energy. Whether plasma ice shape regulation could reduce flight risk is a new problem under the wing with continuous ice. The 3D printed ice shapes were arranged on the leading edge of the wing based on NACA0012 airfoil, aiming to simulate the configuration after ice shape regulation. And the aerodynamic parameters were obtained by wind tunnel experiments. The experimental results showed that the ratio of signal regulation ice width d to chord length of the wing b A determined the aerodynamic characteristics, and the aerodynamic characteristics changed better compared with configuration of the continuous ice. However, the flight risk of the wing under given regulation ratio is unknown. Based on the straight and swept wing after regulating, the flight safety boundaries were simulated by the reachable set method. Further, a method of quantitative assessment of flight risk is proposed. Quantitative values of risk were calculated. The results show that the flight risk all decreases from level 2 to level 4 compared with configuration of the continuous ice when d / b A equals 0.15 under conditions of swept and straight wing.

The optimization method of wing ice shape regulation based on flight dynamics characteristics.

Ice on aircraft wing changes the aircraft aerodynamic shape, and has negative effects on flight dynamic characteristics, seriously threatening flight safety. Plasma ice shape regulation is a new de-icing method. Plasma actuator produces an apparent thermal effect, which is designed to dissolve the continuous ice into intermittent ice pieces. How to achieve the optimal regulation ice shape to improve the flight dynamics characteristics under icing conditions is a technical problem restricting the application of this method. A simulation ice shape based on previous ice tunnel experiments and a scale model of swept wing were established. The aerodynamic parameters of no ice, full ice, and two regulation ice schemes were obtained based on wind tunnel. Six degrees of freedom flight dynamics model was established, and flight simulation had been carried out. As the analysis of trim characteristics, dynamic stability, and maneuverability, flight dynamics characteristics were better improved when the ratio of ice width to the mean aerodynamic chord was 0.15. The evaluation method of plasma ice shape regulation schemes was proposed. The proposed method, which can compare and optimize the arrangement of plasma actuators, realized the optimal regulation ice shape on the premise of balancing flight safety and energy consumption.

Tracking the gastrointestinal digestive and metabolic behaviour of Dendrobium officinale polysaccharides by fluorescent labelling.

Recently, Dendrobium officinale polysaccharide (DOP), a typical acetylated glucomannan, has been widely applied in functional foods owing to its excellent bioactivity. However, the insufficiency of studies on in vivo process severely limits the further utilization of DOP. The aim of this study was to systematically investigate the gastrointestinal digestive behaviour of DOP after oral administration by labelling it with two fluorescein aminopyrene-1,3,6-trisulfonic acids, trisodium salt (APTS) and cyanine 7.5 (Cy7.5). Combining the results of NIR imaging and HPGPC, we found that DOP was poorly absorbed directly in the prototype form; instead, DOP moved with the intestinal contents to the distal part of the intestine, where Bacteroides aggregated for a prolonged time and was metabolized to oligosaccharide-like substances. In contrast, the digestive degradation of DOP in pseudo-sterile mice with a targeted clearance of Bacteroides significantly weakened, which provided the basis and direction for the subsequent search for more specific metabolic pathways of DOP in vivo.

Oral absorption characteristics and mechanisms of a pectin-type polysaccharide from Smilax china L. across the intestinal epithelium.

The elucidation of the oral absorption of natural polysaccharides contributes to their further research and utilization. Herein, to explore the absorption of a pectin-type polysaccharide from Smilax china L. (SCLP), SCLP was respectively fluorescently labeled with fluorescein-5-thioicarbazide (FSCLP) and Cyanine7 amine (Cy7-SCLP) for in vitro and in vivo tracking. The near-infrared imaging demonstrated that Cy7-SCLP was absorbable in the small intestine and distributed in the liver and kidney after oral administration. Subsequently, in vitro intestinal epithelial tissue experiments showed that the jejunum was the dominant site of FSCLP transport. Further transport studies in the Caco-2 cell monolayer illustrated that FSCLP was delivered across the monolayer via transcellular transport by caveolae-mediated endocytosis and macropinocytosis together with paracellular transport by reversibly affecting tight junctions. In summary, this work presents the oral absorption characteristics and mechanisms of SCLP through the intestinal epithelium, which will facilitate the further development of SCLP and pectin polysaccharides.

Complete genome sequence of a duck hepatitis a virus type 3 identified in eastern China.

We report here the complete genome sequence of a novel duck hepatitis A virus type 3 (DHAV-3) isolated from a dead Cherry Valley duckling in eastern China. The whole genomic nucleotide sequence and polyprotein amino acid sequence of the virus had higher homology with those of Chinese DHAV-3 isolates, medium homology with those of Korean DHAV-3 isolates, and the lowest homology with those of Vietnamese isolate DN2. The result indicated that the genetic evolution of DHAV-3 isolates had obvious geographical features.

Protective effects of total flavonoids of Bidens pilosa L. (TFB) on animal liver injury and liver fibrosis.

The hepatoprotective effects of total flavonoids of Bidens pilosa L. (TFB), a traditional Chinese medicine were evaluated in carbon tetrachloride (CCl(4))-induced liver injury in mice and rats. Total flavonoids of Bidens pilosa L. (25, 50 and 100mg/kg) were administered via gavage daily for 10 days to CCl(4)-treated mice as well as TFB (30, 60 and 90mg/kg) administered for 6 weeks to CCl(4)-treated rats. Liver index (liver weight/body weight), serum levels of transaminases (alanine aminotransferase, ALT and aspartate aminotransferase, AST), hepatic malondialdehyde (MDA) content, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were evaluated following the 10 days treatment in mice. In addition histopathologic changes and nuclear factor-kappaB (NF-kappaB) expression of the liver were detected with hematoxylin-eosin (HE) and immunohistochemistry methods, respectively. The results showed that TFB (50 and 100mg/kg) effectively reduced the CCl(4)-induced elevated liver index, serum ALT, AST levels, hepatic MDA content, and restored hepatic SOD, GSH-Px activities in acute liver injury mice. TFB (60 and 90mg/kg) treatment significantly inhibited NF-kappaB activation in liver fibrosis of rats. The histopathological analysis suggested that TFB reduced the degree of liver injury in mice and severity of liver fibrosis in rats. These results suggested that TFB had a protective and therapeutic effect on animal liver injury, which might be associated with its antioxidant properties and inhibition of NF-kappaB activation.