Background: Duck circovirus (DuCV) is a potential immunosuppressive virus that causes feather disorders in young ducks. In this study, DuCV obtained from various species of ducks was investigated by polymerase chain reaction (PCR) in southern and southwestern China (Guangdong, Guangxi and Yunnan provinces) from 2018 to 2019. Results: A total of 848 bursa samples were collected from dead Mulard, Cherry Valley Pekin, Muscovy and Mallard ducks from duck farms. The positivity rate of DuCV in the total sample was approximately 36.91%. We found that the prevalence of DuCV in Yunnan (43.09%) was higher than those in Guangxi (34.38%) and Guangdong (34.4%). However, the positivity rates of DuCV in the four duck species were not significantly different (P > 0.05). Nineteen randomly selected complete viral genomes were sequenced. The complete genomes of the DuCV were 1987 to 1995 nt in length, and were 81.7-99.3% homologous to the other 57 sequences in GenBank. Phylogenetic analyses based on the complete genomes of 76 DuCVs showed that the 19 novel DuCV sequences from Guangdong and Guangxi provinces mainly belonged to the DuCV-1 and DuCV-2 genetic groups, respectively. However, the two genotype groups coexisted in Yunnan Province. In addition, recombination analysis showed putative recombination sites in 3 strains in Yunnan that originated from strains Guangdong and Guangxi. Interestingly, the epidemiological investigation showed that Mulard ducks, Cherry Valley Pekin ducks and Muscovy ducks more than 4 weeks old were more susceptible to infection with the novel DuCV than ducks less than 4 weeks old. Conclusions: These data provide insight into the molecular epidemiology and genetic diversity of DuCVs circulating in southern and southwestern China for the first time.
Surface modification was conducted on the basic magnesium sulfate whiskers (MSW) using sodium stearate. The modification performance was evaluated by comparing the activation index, oil absorption value, rest angle, and dispersibility in polypropylene (PP) resin prior to and after treatment. It was found that the surface properties of the whiskers were improved by sodium stearate modification. In particular, the improvement in the dispersibility in PP was significant. Surface characterization was conducted using scanning electron microscopy (SEM), thermogravimetric-differential scanning calorimetry (TG-DSC) and fourier transform infrared spectroscopy (FTIR) for the raw and modified whiskers. The results indicated the co-existence of both chemical and physical adsorptions of sodium stearate on the surfaces of MSW.
] content but also the substituent groups in aromatics. A reaction mechanism of nitration over this new catalyst was proposed. The catalytic activity of this catalyst decreased slightly after fifth runs in the synthesis of nitrotoluene.
In this paper, a one-dimensional bi-stage phononic band gap (PBG) structure based on double local resonant effects is presented to reduce the torsional vibration for the first time. A unit cell of the bi-stage PBG structure is composed of two harmonic LR oscillators in the radial direction, distributed periodically along the shaft. A new method, combining the transfer matrix method and the lumped-mass method is proposed to study the torsional vibration band gaps of the double PBG-like shaft theoretically and proved by the finite element method. The results show that the mid-gap frequency of the bi-stage PBG structure shaft is lower than that in the one-stage PBG shaft and the relative width of the band gaps reaches 1.3 with the average attenuation of the vibration amplitude about 40dB.
A series of polystyrene-supported 1-(propyl-3-sulfonate)-3-methy-imidazolium hydrosulfate acidic ionic liquid (PS-[SO3H-PMIM][HSO4]) catalysts with different [SO3H-PMIM][HSO4] contents were prepared and tested for esterification of n-butyl alcohol with acetic acid. It was found that the reactivity of the catalyst increased with increasing [SO3H-PMIM][HSO4] content, and best yield of n-Butyl acetate of 98% was obtained using PS-[SO3H-PMIM][HSO4]1 within 1.5h. The catalytic activity of this catalyst decreased slightly after fifth using.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.