Dependence of Tensile Properties and Fracture Behaviors on the Fractions of Continuous and Discontinuous Precipitates in Peak-Aged AZ80A Magnesium Alloy.

After T5 (forging + aging) and different T6 (forging + solution + aging) heat treatments, the AZ80A Mg alloys exhibited microstructures with different fractions of continuous precipitate (CP) regions and discontinuous precipitate (DP) regions. The effects of the fractions of DP regions and CP regions on the tensile properties and fracture behaviors were investigated using microstructural characterizations and analysis. The results showed that increasing the fraction of DP regions enhanced the yield strength and tensile strength at room temperature. However, at the same high temperature, increasing the fractions of DP regions improved the elongation but deteriorated the tensile strength significantly. The different resultant tensile properties at different temperatures were caused by the different precipitation-strengthening effects in the CP and DP regions. The strengthening contribution of the DP regions was more effective at room temperature but became inferior to the effect brought about by the CP regions at high temperatures. Micro-cracks were usually initiated and propagated in the CP regions at room temperature. At high temperatures, however, micro-voids formed more easily in the DP regions, and the fracture path preferred to locate there.

Molecular detection and genomic characterization of porcine circovirus 3 in pigs from Northeast China.

BACKGROUND: First identified in the United States in 2016, porcine circovirus type 3 (PCV3) is a newly emerging porcine circovirus exhibiting a wide range of clinical syndromes, which may be associated with the pathogenicity observed in pigs. RESULTS: The aim of this study was to identify and characterize the full genome sequence of PCV3 strains circulating in Northeast China. Herein, 105 lung samples isolated from sick pigs in Northeast China during 2018 were analyzed for PCV3. Using PCR, the total PCV3-positive rate was 33.3% (35/105), with rates of 17.8% (8/45), 66.7% (10/15), and 37.8% (17/45) in Heilongjiang, Jilin, and Liaoning province, respectively. Additionally, our findings showed that PCV3-positive samples had a high rate of co-infection with PCV2, PPV6, and PPV7. To study the evolution of the PCV3 in Northeast China, we sequenced the entire genome of 13 strains of PCV3. The results of phylogenetic analyses revealed that PCV3 could be divided into two clades, PCV3a and PCV3b. Interestingly, a G deletion at position 1072 was found in the 1999 nt genome of PCV3-CN2018LN-4 (MH277118). The G deletion terminated replicase protein translation and induced a truncated replicase protein. CONCLUSION: These results contribute to the understanding of PCV3 molecular epidemiology and evolution in Northeast China. A new strain of PCV3 with truncated replicase protein was identified.

SIV-Specific Antibodies are Elicited by a Recombinant Fowlpox Virus Co-expressing SIV Gag and envT.

Given the failures of past HIV-1 vaccine clinical trials, potential HIV-1 vaccine candidates should be rigorously screened in preclinical models including simian immunodeficiency virus (SIV) primate models and small animal models. In this study, we tested the immunogenicity of a recombinant fowlpox virus (rFPV) expressing the SIV gag and SIV envT (rFPVsg-se) proteins in BALB/c mice, to establish a foundation for further development. rFPVsg-se was constructed through homologous recombination techniques and purified through plaque screening assays using enhanced green fluorescent protein as the reporter gene. The integration, transcription, and translation of the SIV genes were measured by PCR (genomic DNA), RT-PCR (RNA), Western-blot, respectively. The levels of SIV-specific antibodies were assessed by ELISA following a single immunization (n = 18/group) or a prime-boost strategy (n = 24/group) with rFPVsg-se and compared to FPV and PBS controls. Residual virus was measured in distant organs following immunization using PCR. SIV-specific IgG titers against gag and gp120 were detected following single vaccination and the prime-boost. As expected the titers were higher following the prime-boost approach. The levels of Gag- and gp120-specific antibodies were significantly higher than controls (p < 0.01) 14 days after the booster immunization. Residual rFPVSg-Se was detected in the muscle at the site of injection, but not in distant organs, from day 1-7 post immunization. In summary, rFPVsg-se induced high levels of SIV-specific antibodies suggesting it may be a viable candidate for further development.

Construction of an attenuated goatpox virus AV41 strain by deleting the TK gene and ORF8-18.

Goatpox virus (GTPV) is prevalent in goats and is associated with high mortality. This virus causes fever, skin nodules, lesions in the respiratory and lymph node enlargement. Considering the safety risks and side effects of vaccination with attenuated live GPTV vaccine strain AV41, an attenuated goatpox virus (GTPV-TK-ORF), was constructed by deleting non-essential gene fragments without affecting replication and related to the virulence and immunomodulatory functions of the goatpox virus AV41 strain (GTPV-AV41) using homologous recombination and the Cre (Cyclization Recombination Enzyme)/Loxp system. The results of both in vivo and in vitro experiments demonstrated that GTPV-TK-ORF was safer than wild type GTPV-AV41, possessed satisfactory immunogenicity, and could protect goats from a virulent GTPV-AV40 infection. Moreover, the IFN-γ, GTPV-specific antibody, and neutralizing antibody levels in the GTPV-TK-ORF-immunized group were significantly higher than that in the normal saline control group following immunization (P < 0.01). Thus, GTPV-TK-ORF may be used as a potential novel vaccine and viral vector with good safety and immunogenicity.

Ionic liquid-stabilized non-spherical gold nanofluids synthesized using a one-step method.

Ionic liquid (IL)-stabilized non-spherical gold nanofluids have been synthesized by a one-step method in aqueous solution. The whole reaction proceeded in room temperature. In the presence of amino-functionalized ionic liquids, gold nanofluids with long-wave surface plasmon resonance (SPR) absorption (>600 nm) could be obtained by adopting tannic acid as the reductant. The specific SPR absorption was related to the non-spherical gold nanoparticles including gold triangle, decahedra, and icosahedra nanocrystals. All the nanocrystals were observed by transmission electron microscopy. It was deduced that the formation of non-spherical gold nanofluids was related to the hydroxyls in tannic acid while IL acted as the synthesis template.