SY18ΔL60L: a new recombinant live attenuated African swine fever virus with protection against homologous challenge

IntroductionAfrican swine fever (ASF) is an acute and highly contagious disease and its pathogen, the African swine fever virus (ASFV), threatens the global pig industry. At present, management of ASF epidemic mainly relies on biological prevention and control methods. Moreover, due to the large genome of ASFV, only half of its genes have been characterized in terms of function.MethodsHere, we evaluated a previously uncharacterized viral gene, L60L. To assess the function of this gene, we constructed a deletion strain (SY18ΔL60L) by knocking out the L60L gene of the SY18 strain. To evaluate the growth characteristics and safety of the SY18ΔL60L, experiments were conducted on primary macrophages and pigs, respectively.ResultsThe results revealed that the growth trend of the recombinant strain was slower than that of the parent strain in vitro. Additionally, 3/5 (60%) pigs intramuscularly immunized with a 105 50% tissue culture infectious dose (TCID50) of SY18ΔL60L survived the 21-day observation period. The surviving pigs were able to protect against the homologous lethal strain SY18 and survive. Importantly, there were no obvious clinical symptoms or viremia.DiscussionThese results suggest that L60L could serve as a virulence- and replication-related gene. Moreover, the SY18ΔL60L strain represents a new recombinant live-attenuated ASFV that can be employed in the development of additional candidate vaccine strains and in the elucidation of the mechanisms associated with ASF infection

Time-series co-registration for Sentinel-1 TOPS SAR Data

TOPS mode is the default imaging mode of Sentinel-1 satellites, which requires an overall azimuth co-registration accuracy of 0.001 pixels to ensure that the interferometric phase difference of consecutive bursts is less than 3°. Although the ESD technique is an effective method to correct the azimuth residual shift, the accuracy will decrease due to the abrupt loss of coherence. To solve this issue, this paper presents a method to improve the accuracy of TOPS co-registration by maximizing time-series coherence. The method focuses on selecting interferometric pairs with optimal coherence and simultaneously preserve the temporal network loops by Bellman-Ford algorithm. The improvement of network can reduce the error propagation caused by low coherence during the least-squares adjustment, and therefore improve the performance of ESD estimation. Based on synthetic data and real data covering the Weihe plain, we evaluate the performance of proposed method against the state-of-the-art techniques. The results demonstrate the effectiveness of the proposed method

Experimental study on eccentric compressive behaviors of 6061-T6 aluminum tubular long columns filled with concrete

In this paper, eccentric compressive experiments of 12 circular and 6 square concrete-filled 6061-T6 aluminum tubular (CFAT) long columns were carried out. The influence of the section form, thickness of aluminum tube, slenderness ratio, and eccentricity on the flexural performance of CFAT long columns was investigated. The results showed that all the specimens exhibited flexural-dominated failure. The variation of eccentricity had little impact on the overall failure mode of the aluminum tube, while it dramatically influenced the failure mode of the internal concrete. The internal concrete failed in concrete crushing for all the square columns, while it remained intact for the circular columns. This indicates that circular tubes provide a better constraint effect on the internal concrete, there by increasing the ultimate strain of concrete under compression. It was also found that the increase of eccentricity leads to the weakening of the confinement afforded to the internal concrete, while the increase of slenderness ratio has no obvious effect on the restraining effect. Finally, the applicability of current design provisions for concrete-filled steel tubular (CFST) long columns to CFAT long columns was evaluated, and design suggestions were proposed