The mortality rate of hemorrhagic African swine fever (ASF), which targets domestic pigs and wild boars is caused by African swine fever virus (ASFV), can reach 100%. Since the first confirmed ASF outbreak in China on 3 August 2018, 156 ASF outbreaks were detected in 32 provinces. About 1,170,000 pigs were culled in order to halt further spread. There is no effective treatment or vaccine for it and the present molecular diagnosis technologies have trade-offs in sensitivity, specificity, cost and speed, and none of them cater perfectly to ASF control. Thus, a technology that overcomes the need for laboratory facilities, is relatively low cost, and rapidly and sensitively detects ASFV would be highly valuable. Here, we describe an RAA-Cas12a-based system that combines recombinase aided amplification (RAA) and CRISPR/Cas12a for ASFV detection. The fluorescence intensity readout of this system detected ASFV p72 gene levels as low as 10 aM. For on-site ASFV detection, lateral-flow strip readout was introduced for the first time in the RAA-Cas12a based system (named CORDS, Cas12abased On-site and Rapid Detection System). We used CORDS to detect target DNA highly specifically using the lateral-flow strip readout and the assay displayed no crossreactivity to other 13 swine viruses including classical swine fever (CSF). CORDS could identify the ASFV DNA target at femtomolar sensitivity in an hour at 37 • C, and only requires an incubator. For ease of use, the reagents of CORDS were lyophilized to three tubes and remained the same sensitivity when stored at 4 • C for at least 7 days. Thus, CORDS provide a rapid, sensitive and easily operable method for ASFV on-site detection. Lyophilized CORDS can withstand long-term transportation and storage, and is ready for field-based applications.
It is crucial for the physical realization of quantum information networks to first establish entanglement among multiple space-separated quantum memories and then, at a user-controlled moment, to transfer the stored entanglement to quantum channels for distribution and conveyance of information. Here we present an experimental demonstration on generation, storage, and transfer of deterministic quantum entanglement among three spatially separated atomic ensembles. The off-line prepared multipartite entanglement of optical modes is mapped into three distant atomic ensembles to establish entanglement of atomic spin waves via electromagnetically induced transparency light–matter interaction. Then the stored atomic entanglement is transferred into a tripartite quadrature entangled state of light, which is space-separated and can be dynamically allocated to three quantum channels for conveying quantum information. The existence of entanglement among three released optical modes verifies that the system has the capacity to preserve multipartite entanglement. The presented protocol can be directly extended to larger quantum networks with more nodes.
13The mortality rate of hemorrhagic African swine fever (ASF), which targets domestic pigs and is caused 14 by African swine fever virus (ASFV), can reach 100%. ASF has been reported in 25 Chinese provinces 15 since August 2018. There is no effective treatment or vaccine for it and the present molecular diagnosis 16 technologies have trade-offs in sensitivity, specificity, cost and speed, and none of them cater perfectly 17 to ASF control. Thus, a technology that overcomes the need for laboratory facilities, is relatively low 18 cost, and rapidly and sensitively detects ASFV would be highly valuable. Here, we describe an RAA-19 Cas12a-based system that combines recombinase-aided amplification (RAA) and CRISPR/Cas12a for 20 ASFV detection. The fluorescence intensity readout of this system detected ASFV p72 gene levels as 21 low as 10 aM. For on-site ASFV detection, lateral-flow strip readout was introduced for the first time in 22 the RAA-Cas12a based system (named CORDS, Cas12a-based On-site and Rapid Detection System).
23We used CORDS to detect target DNA highly specifically using the lateral-flow strip readout. CORDS 24 could identify the p72 gene at femtomolar sensitivity in an hour at 37°C, and only requires an incubator.
25For ease of use, the regents of CORDS was lyophilized to three tubes and remained the same sensitivity 26 when stored at 4 °C for at least 7 days. Thus, CORDS provides a rapid, sensitive and easily operable 27 method for ASFV on-site detection. Lyophilized CORDS can withstand long-term transportation and 28 storage, and is ready for field applications. 29 30
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