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Abstrakt

In order to compare the pathogenicity of different Tembusu virus (TMUV) strains from geese, ducks and chickens, 56 5-day-old Cherry Valley ducklings which were divided into 7 groups and infected intramuscularly with 7´105 PFU/ml per duck of six challenge virus stocks. The clinical signs, weight gain, mortality, macroscopic and microscopic lesions, virus loads in sera of 1, 3, 5, 7, 11 and 14 dpi and serum antibody titers were examined. The results showed that these viruses could make the young ducks sick, but the clinical signs differed with the different species-original strains. All the experimental groups lose markedly in weight gain compared to the control, but there were no obvious distinctions in weight gains, as well as macroscopic and microscopic lesions of dead ducks between the infected groups. However, the groups of waterfowl-derived strains (from geese and ducks) showed more serious clinical signs and higher relative expressions of virus loads in sera than those from chicken-derived. The mortality of waterfowl groups was 37.5%, and the greatest mortality of chicken groups was 12.5%. The serum antibodies of the geese-species group JS804 appeared earlier and were higher in the titers than others. Taken toghter, the pathogenicity of waterfowl-derived TMUV was more serious than chicken-derived TMUV and JS804 could be chosen as one TMUV vaccine strain to protect from the infection.
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Abstrakt

As-cast Mg-6Li-0.3Zn-0.6Y and Mg-6Li-1.2Zn-1.2Y (wt%) alloys were prepared and extruded at 260 oC with an extrusion ratio of 25. The microstructure and mechanical behavior of as-cast and extruded alloys are reported and discussed. The results show that Mg-6Li-1.2Zn- 1.2Y alloy is composed of α-Mg, β-Li, and W-Mg3Zn3Y2 phases while Mg-6Li-0.3Zn-0.6Y alloy contains α-Mg, β-Li, W-Mg3Zn3Y2 phase and X-Mg12ZnY. After hot extrusion, the microstructure of specimens is refined and the average grains size of extruded alloys is 15 μm. Dynamic recrystallization occurs during the extrusion, leading to grain refinement of test alloys. Both the strength and elongation of test alloys are improved by extrusion. The extruded Mg-6Li-0.3Zn-0.6Y alloy possesses an ultimate strength of 225 MPa with an elongation of 18% while the strength and elongation of Mg-6Li-1.2Zn-1.2Y alloy are 206 MPa and 28%, respectively. The X-phase in Mg-6Li-0.3Zn- 0.6Y is beneficial to the improvement of strength, but will lead to the decrease of ductility.
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Abstrakt

Self-biting disease occurs in most farmed fur animals in the world. The mechanism and rapid detection method of this disease has not been reported. We applied bulked sergeant analysis (BSA) in combination with RAPD method to analyze a molecular genetic marker linked with self-biting trait in mink group. The molecular marker was converted into SCAR and loop-mediated isothermal amplification (LAMP) marker for rapid detection of this disease. A single RAPD marker A10 amplified a specific band of 1000bp in self-biting minks. The sequences of the bands exhibited 73% similarity to the Canis Brucella. SCAR and LAMP marker were designed for the specific fragment of RAPD marker A10 and validated in 30 self-biting minks and 30 healthy minks. c2 test showed difference (p<0.05) with SCAR and significant difference (p<0.01) with LAMP in the detection rate between the two groups, but LAMP method was more accurate than SCAR method. This indicated that LAMP can be used as a positive marker to detect self-biting disease in minks.
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