RESUMEN
The graft-through synthesis of Janus graft block copolymers (GBCPs) from branched macromonomers composed of various combinations of homopolymers is presented. Self-assembly of GBCPs resulted in ordered nanostructures with ultra-small domain sizes down to 2.8â nm (half-pitch). The grafted architecture introduces an additional parameter, the backbone length, which enables control over the thermomechanical properties and processability of the GBCPs independently of their self-assembled nanostructures. The simple synthetic route to GBCPs and the possibility of using a variety of polymer combinations contribute to the universality of this technique.
RESUMEN
Porcine circovirus type 2 (PCV2) belongs to the family Circoviridae, and is the causative agent of post-weaning multisystemic wasting syndrome (PMWS) in pigs. In this study, phylogenetic analyses of three complete PCV2 genomic sequences from Hong Kong suggest that natural recombination happened among different lineages of PCV2. A preliminary investigation of the parental strains of these potential recombinants was carried out using bootscanning. Statistical significance of this recombination event was tested and positions of the potential recombination breakpoints were estimated in a maximum-likelihood framework. The recombinant breakpoints were estimated to be located within the origin of replication (ori) and replicase (rep) gene of PCV2. Interestingly, several GenBank sequences of PCV2 in mainland China were found to have a recombination pattern similar to that of the potential PCV2 recombinants from Hong Kong, implying that this recombinant genotype might already be widespread within mainland China.