Temperature gradient zone melting (TGZM) method was used to obtain bulk Si continuously for the efficient separation and purification of primary Si from the Si-Al alloy in this work. The effects of alloy thickness, temperature gradient and holding time in TGZM purification technology were investigated. Finally, the continuous growth of bulk Si without eutectic inclusions was obtained. The results showed that the growth rate of bulk Si was independent of the liquid zone thickness. When the temperature gradient was changed from 2.48 K/mm to 3.97 K/mm, the growth rate of bulk Si was enhanced from 7.9×10–5 mm/s to 2.47×10–4 mm/s, which was increased by about 3 times. The bulk Si could grow continuously and the growth rate was decreased with the increase of holding time from 1 h to 5 h. Meanwhile, low refining temperature was beneficial to the removal of impurities. With a precipitation temperature of 1460 K and a temperature gradient of 2.48 K/mm, the removal rates of Fe, P and B were 99.8%, 94.0% and 63.6%, respectively.
The data aggregation process of wireless sensor networks faces serious security problems. In order to defend the internal attacks launched by captured nodes and ensure the reliability of data aggregation, a secure data aggregation mechanism based on constrained supervision is proposed for wireless sensor network, which uses the advanced LEACH clustering method to select cluster heads. Then the cluster heads supervise the behaviors of cluster members and evaluate the trust values of nodes according to the communication behavior, data quality and residual energy. Then the node with the highest trust value is selected as the supervisor node to audit the cluster head and reject nodes with low trust values. Results show that the proposed mechanism can effectively identify the unreliable nodes, guarantee the system security and prolong the network lifetime.
Sapelovirus A (SV-A) is a positive-sense single-stranded RNA virus which is associated with acute diarrhea, pneumonia and reproductive disorders. The virus capsid is composed of four proteins, and the functions of the structural proteins are unclear. In this study, we expressed SV-A structural protein VP1 and studied its antigenicity and immunogenicity. SDS-PAGE analysis revealed that the target gene was expressed at high levels at 0.6 mM concentration of IPTG for 24 h. The mouse polyclonal antibody against SV-A VP1 protein was produced and reached a high antiserum titer (1: 2,048,000). Immunized mice sera with the recombinant SV-A VP1 protein showed specific recognition of purified VP1 protein by western blot assay and could recognize native SV-A VP1 protein in PK-15 cells infected with SV-A by indirect immunofluorescence assay. The successfully purified recombinant protein was able to preserve its antigenic determinants and the generated mouse anti-SV-A VP1 antibodies could recognize native SV-A, which may have the potential to be used to detect SV-A infection in pigs.
To keep genetic diversity, flowering plants have developed a self-incompatibility system, which can prevent self-pollination. It has been reported that calcium concentration in pistil papilla cells was increased after self-pollination in transformed self-incompatible Arabidopsis thaliana. In this study, we found that CML27 changed its expression level for both mRNA and protein when compared to transcriptome and proteome. At the same time, CML27 was expressed in the anther and pistil at a high level and reached up to 5-fold up-regulated expression in the pistil at 1 h post-pollination when compared to 0 min. In order to find out potential proteins that may interact with BoCML27, BoCML27 was expressed in and isolated from E. coli. After its co-incubation with Brassica oleracea pistil proteins, the products were separated on SDS-PAGE gels. We found a specific band at the position between 130–180 kDa. Through LC-MS-MS (Q-TOF) analysis, eight proteins were identified from the band. The proteins include 26S proteasome non-ATPase regulatory (26S), Phospholipase D, alpha 2 (PLDα2) involved in Ca2+ binding and Coatomer subunit alpha-2-like (Coatomer) involved in vesicle mediated transport. All of these identified proteins provide new insights for the self-incompatibility response in B. oleracea, specific for increasing Ca2+ concentration in pistil papilla cells.