Efficacy improvement in polymer LEDs via silver-nanoparticle doping in the emissive layer.

The coupling of surface plasmons and excitons in the emissive layer (EML) can improve the performance of polymer light-emitting diodes (PLEDs). Silver nanoparticles (Ag-NPs) with a decahedron structure are prepared by the chemical reduction and photochemical methods and doped directly into the EML after the phase-transfer process. The surface plasmon resonance effect of Ag-NPs, which makes full use of quenched excitons and increases the efficiency of excitons in the EML in a PLED, enhances the current efficacy by a factor of 75 relative to that of the undoped reference device (from 0.22 to 16.64 cd/A). These results demonstrate that Ag-NPs can assist in simple and low-cost fabrication of high-performance polymer optoelectronic devices.

Taxonomic relationships within the pan-oriental narrow-mouth toad Microhyla ornata as revealed by mtDNA analysis (Amphibia, Anura, Microhylidae).

A molecular phylogenetic survey was conducted using mtDNA sequences of 12S and 16S rRNA, and cyt-b genes to examine taxonomic relationships among populations of the Pan-Oriental microhylid, Microhyla ornata, from India, Bangladesh, Thailand, Laos, China, Taiwan, and the Ryukyu Archipelago of Japan. Two discrete clades are recognized within this species, one consisting of populations from India and Bangladesh, and the other encompassing the remaining populations. In the latter clade, populations from the Ryukyu Archipelago are clearly split from the rest (populations from Taiwan and the continent) with considerable degrees of genetic differentiations. Each of the three lineages is judged to represent a good species, and the name Microhyla ornata is restricted to the South Asian populations. For the populations from Taiwan and a wide region from China to Southeast Asia, the name Microhyla fissipes should be applied, whereas the Ryukyu populations are most appropriately referred to as Microhyla okinavensis, although further substantial genetic differentiations are recognized among some island group populations within this last species.

Phylogeny of Raninae (Anura: Ranidae) inferred from mitochondrial and nuclear sequences.

Phylogenetic relationships among representative species of the subfamily Raninae were investigated using approximately 2000 base pairs of DNA sequences from two mitochondrial (12S rRNA, 16S rRNA) and two nuclear (tyrosinase, rhodopsin) genes. Phylogenetic trees were reconstructed using maximum parsimony, Bayesian, and maximum likelihood analyses. Comparison between the nuclear and mitochondrial findings suggested that our final combined data has higher resolving power than the separate data sets. The tribes Stauroini and Ranini formed a sistergroup relationship, and within Ranini, ten major clades were consistently resolved among all analyses based on the final combined data, although the phylogenetic relationships among the ten clades were not well resolved. Our result refuted several previous taxonomic divisions: the genus Pseudoamolops was invalid, and the monophyly of the genera Amolops and Rana were not supported. We suggest elevating Raninae to familial status, and recognizing within the family, at least twelve genera including Staurois, Meristogenys, Clinotarsus, Amolops, Hylarana, Babina, Odorrana, Pseudorana, Rana, Lithobates, Glandirana, and Pelophylax. A broader sampling of species and data from more molecular markers are needed to confidently resolve the phylogenetic relationships among Ranidae.