RESUMO
Two-dimensional (2D) molybdenum nitride (MoN) nanosheets are promising anode materials for improved lithium-ion batteries. However, the reported synthesis methods of MoN generally rely on high-temperature and complex procedures with low cost efficiency. Herein, we report a facile one-pot synthesis of 2D MoN nanosheets at a low temperature of 400 °C via a solid-state reaction of molybdenum disulfide, sulfur and sodium amide in an autoclave. When employed as the anode material for lithium ion batteries, the as-developed MoN electrode exhibits outstanding cyclability with a high capacity retention of 898 mA h g-1 over 400 cycles at a current rate of 200 mA g-1 as well as a superb rate capability with a capacity of 505 mA h g-1 at a high rate up to 2 A g-1. The excellent lithium storage performance of the MoN electrode is attributed to its advantageously high conductivity and unique 2D nanostructure.
RESUMO
Magnolia grandiflora is an important medicinal, ornamental and horticultural plant species. The chloroplast (cp) genome of M. grandiflora was sequenced using a 454 sequencing platform and the genome structure was compared with other related species. The complete cp genome of M. grandiflora was 159623 bp in length and contained a pair of inverted repeats (IR) of 26563 bp separated by large and small single copy (LSC, SSC) regions of 87757 and 18740 bp, respectively. A total of 129 genes were successfully annotated, 18 of which included introns. The identity, number and GC content of M. grandiflora cp genes were similar to those of other Magnoliaceae species genomes. Analysis revealed 218 simple sequence repeat (SSR) loci, most composed of A or T, contributing to a bias in base composition. The types and abundances of repeat units in Magnoliaceae species were relatively conserved and these loci will be useful for developing M. grandiflora cp genome vectors. In addition, results indicated that the cp genome size in Magnoliaceae species and the position of the IR border were closely related to the length of the ycf1 gene. Phylogenetic analyses based on 66 shared genes from 30 species using maximum parsimony (MP) and maximum likelihood (ML) methods provided strong support for the phylogenetic position of Magnolia. The availability of the complete cp genome sequence of M. grandiflora provides valuable information for breeding of desirable varieties, cp genetic engineering, developing useful molecular markers and phylogenetic analyses in Magnoliaceae.
Assuntos
Genoma de Cloroplastos , Genoma de Planta , Magnolia/genética , Composição de Bases , Sequência de Bases , Mapeamento Cromossômico , DNA de Cloroplastos/genética , Evolução Molecular , Genes de Cloroplastos , Genes de Plantas , Sequenciamento de Nucleotídeos em Larga Escala , Sequências Repetidas Invertidas , Magnoliaceae/genética , Repetições de Microssatélites , Filogenia , Análise de Sequência de DNA , Especificidade da EspécieRESUMO
OBJECTIVE: To determine the candidate sequences which can be used as DNA barcode to identify species in Caprifoliaceae family by screening out from four different DNA fragments sequences. METHOD: PCR amplification, sequencing efficiency, differential intra- and interspecific divergences, the DNA barcoding gap and identification efficiency were used to evaluate these loci. RESULT: The ITS2 was used as a candidate sequence of DNA barcode to identify the species in Caprifoliaceae family, whose rate of success in identification in genera level was 100% and in species 96.6%, and psbA-trnH as a complementary barcode to ITS2 for Caprifoliaceae.
