The surface plasmon (SP) modulation is a promised way to highly improve the strength of upconversion luminescence (UCL) and expand its applications. In this work, the "islands" Au-Ag alloy fi lm is prepared by an organic removal template method and explored to improve the UCL of NaYF 4 : Yb3+, Tm 3+ /Er 3+ . After the optimization of Au-Ag molar ratio (Au 1.25 -Ag 0.625 ) and the size of NaYF 4 nanoparticles (NPs, ≈7 nm), an optimum enhancement as high as 180 folds is obtained (by refl ection measurement) for the overall UCL intensity of Tm 3+ . Systematic studies indicate that the UCL enhancement factor (EF) increases with the increased size of metal NPs and the increase of diffuse refl ection, with the decreased size of NaYF 4 NPs, with the decreased power density of excitation light and with improving order of multiphoton populating. The total decay rate varies only ranging of about 20% while EF changes signifi cantly. All the facts above indicate that the UCL enhancement mainly originates from coupling of SP with the excitation electromagnetic fi eld. Furthermore, the fi ngerprint identification based on SP-enhanced UCL is realized in the metal/UC system, which provides a novel insight for the application of the metal/UC device.
Here, we describe a tripartite circular single-stranded (ss) DNA mycovirus, named Fusarium graminearum gemytripvirus 1 (FgGMTV1). The genome of FgGMTV1 comprises three circular ssDNA segments (DNA-A, DNA-B, and DNA-C). Sequence alignments and phylogenetic analyses showed that FgGMTV1 is nested within the family Genomoviridae. We also constructed the first infectious DNA clones of a DNA mycovirus. Our results show that DNA-A and DNA-B are mutually interdependent for their replication and are associated with severely reduced colony growth and hypovirulence. DNA-C relies on DNA-A and DNA-B for replication and is necessary for the recovery of abnormal fungal phenotypes. DNA-C also enhances the accumulation of viral DNA in infected fungi and permits stable colonization and easy transmission via conidia. This is the first multipartite DNA virus isolated from a fungus. Our phylogenetic analyses also suggest that the multipartite genome of FgGMTV1 may have evolved from a monopartite genome of an ancient genomovirus.
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