RESUMO
The interfacial effect is important for anodes of transition metal dichalcogenides (TMDs) to achieve superior lithium-ion storage performance. In this paper, a MoS2/FeS2 heterojunction is synthesized by a simple hydrothermal reaction to construct the interface effect, and the heterostructure introduces an inherent electric field that accelerates the de-embedding process of lithium ions, improves the electron transfer capability, and effectively mitigates volume expansion. XPS analysis confirms evident chemical interaction between MoS2 and FeS2 via an interfacial covalent bond (Mo-S-Fe). This MoS2/FeS2 anode shows a distinct interfacial effect for efficient interatomic electron migration. The electrochemical performance demonstrated that the discharge capacity can reach up to 1217.8 mA h g-1 at 0.1 A g-1 after 200 cycles, with a capacity retention rate of 72.9%. After 2000 cycles, the capacity retention is about 61.6% at 1.0 A g-1, and the discharge capacity can still reach 638.9 mA h g-1. Electrochemical kinetic analysis indicated an enhanced pseudocapacitance contribution and that the MoS2/FeS2 had sufficient adsorption of lithium ions. This paper therefore argues that this interfacial engineering is an effective solution for designing sulfide-based anodes with good electrochemical properties.
RESUMO
The rational design of the heterogeneous interfaces enables precise adjustment of the electronic structure and optimization of the kinetics for electron/ion migration in energy storage materials. In this work, the built-in electric field is introduced to the iron-based anode material (Fe2O3@TiO2) through the well-designed heterostructure. This model serves as an ideal platform for comprehending the atomic-level optimization of electron transfer in advanced lithium-ion batteries (LIBs). As a result, the core-shell Fe2O3@TiO2 delivers a remarkable discharge capacity of 1342 mAh g-1 and an extraordinary capacity retention of 82.7% at 0.1 A g-1 after 300 cycles. Fe2O3@TiO2 shows an excellent rate performance from 0.1 A g-1 to 4.0 A g-1. Further, the discharge capacity of Fe2O3@TiO2 reached 736 mAh g-1 at 1.0 A g-1 after 2000 cycles, and the corresponding capacity retention is 83.62%. The heterostructure forms a conventional p-n junction, successfully constructing the built-in electric field and lithium-ion reservoir. The kinetic analysis demonstrates that Fe2O3@TiO2 displays high pseudocapacitance behavior (77.8%) and fast lithium-ion reaction kinetics. The capability of heterointerface engineering to optimize electrochemical reaction kinetics offers novel insights for constructing high-performance iron-based anodes for LIBs.
RESUMO
Bactrocera dorsalis (Hendel) is considered to be a highly invasive and destructive agricultural pest due to its strong dispersal and adaptive capacity. Rapid development of insecticide resistance poses a serious threat to the sustainable control of this pest. Here, the resistance mechanisms and invasion pathways of this fly are outlined for a better understanding of the resistance-gene flow pattern and invasion routes. We believe this microreview will provide a glimpse of the native regions, spread and management of resistance, and guide future work on these important topics.
Assuntos
Resistência a Inseticidas/genética , Tephritidae/fisiologia , Distribuição Animal , Animais , Feminino , Fluxo Gênico , Espécies Introduzidas , Masculino , Tephritidae/genéticaRESUMO
Zinc oxide (ZnO) shows great potential as an anode material for advanced energy storage devices owing to its good structural stability and low cost. However, its inferior cycling capacity seriously restricts its practical application. In this work, a pre-lithiation strategy is adopted to construct pre-lithiated ZnO (Li-ZnO) via the facile solid-state reaction method. This well-designed Li-ZnO is polycrystalline, consisting of fine particles. XPS analysis and Raman results confirm the successful pre-lithiation strategy. The pre-lithiation strategy increases the electronic conductivity of Li-ZnO without further carbon coating and suppresses the volume expansion during the electrochemical reaction. As a result, 5 mol% Li-ZnO displays good reversible capacity with a specific capacity of 639 mA h g-1 after 200 cycles at 0.1 A g-1. After 1440 cycles at 1.0 A g-1, the capacity retention is 380 mA h g-1. The pseudocapacitance contribution can reach up to 72.5% at 1.0 mV s-1. Electrochemical kinetic analysis shows that this pre-lithiation strategy can accelerate the lithium-ion diffusion and charge transfer kinetics of the Li-ZnO anode and suppress the pulverization of the electrochemical reaction. This study demonstrates the necessity of developing new anode materials with good cycling stability via this pre-lithiation strategy.
RESUMO
The oriental fruit fly, Bactrocera dorsalis Hendel (Diptera: Tephretidae), is a serious pest of fruits and vegetables and has developed high levels of insecticide resistance. ATP-binding cassette transporter genes (ABC transporters) are involved in mediating the energy-driven transport of many substances across membranes and are closely associated with development and insecticide detoxification. In this study, three ABC transporters in the H subfamily were identified, and the possible roles of these genes in B. dorsalis are discussed. Bioinformatics analysis revealed that those genes are conserved, typical of half-transporters. The expression profiles of BdABCH genes (BdABCHs) in the developmental stages, tissues, and following insecticide exposure, extreme temperature, warm- and cold-acclimated strain, starvation, and desiccation stress were determined by quantitative real-time PCR. Expression of BdABCHs can be detected in various tissues and in different developmental stages. They were most highly expressed in the hindgut and in newly emerged adults. The mRNA levels of BdABCHs in males (including most tissues and body segments) were higher than in females. The expression of BdABCH1 was significantly upregulated 3.8-fold in the cold-acclimated strain, and was significantly upregulated by 1.9-, 3.8- and 4.1-fold in the 0°C, starvation, and desiccation treatments, respectively. Treatment with malathion and avermectin at LD20 and LD30 concentrations produced no obvious changes in the levels of BdABCHs. BdABCHs may be involved in the transport of related hormones during eclosion, as well as water and inorganic salts. BdABCH1 also demonstrated that it is related to the ability to cope with adverse environments.
Assuntos
Transportadores de Cassetes de Ligação de ATP , Tephritidae , Transportadores de Cassetes de Ligação de ATP/genética , Animais , Feminino , Resistência a Inseticidas/genética , Malation , Masculino , Filogenia , Tephritidae/genéticaRESUMO
We sequenced the complete mitochondrial (mt) genome of brown citrus aphid, Aphis (Toxoptera) citricidus (Kirkaldy) and compared it with that of other aphids. The mt genome of A. citricidus is a circular molecule of 16,763â¯bp with 84.0% AT content, containing 13 protein-coding genes (PCGs), 2 rRNAs, 22 tRNAs, a control region (CR) and an additional repeat region between trnE and trnF. Like other aphids, A. citricidus was slightly A-skewed (0.073) and strongly C-skewed (-0.309). Most PCGs used standard ATW start codons and TAA stop codons except nad4, which terminates with an incomplete codon T. All tRNAs and rRNA could be folded as typical secondary structures, except for lacking a dihydrouridine (DHU) arm in tRNASer (AGN). The repeat region possessed the most copy number of repeat motif (~7.5 times) among the reported aphid mt genomes, like in Acyrthosiphon pisum. Both Bayesian inference (BI) and Maximum likelihood (ML) analyses suggested that Toxoptera citricidus should revert to Aphis citricidus. The subfamily Aphidinae is monophyletic, but the Eriosomatinae is non-monophyletic. This study provides new insight into the evolution of aphid mt genomes, as well as useful information for resolving aphid phylogenetic questions.
Assuntos
Afídeos/genética , Genoma Mitocondrial/genética , Filogenia , Sequências Repetitivas de Ácido Nucleico , Animais , Afídeos/classificação , Sequência de Bases , Uso do Códon , Evolução Molecular , Ordem dos Genes , Hibridização de Ácido Nucleico , RNA Ribossômico/genética , RNA de Transferência/genéticaRESUMO
The ATP-binding cassette (ABC) is the largest transporter gene family and the genes play key roles in xenobiotic resistance, metabolism, and development of all phyla. However, the specific functions of ABC gene families in insects is unclear. We report a genome-wide identification, phylogenetic, and transcriptional analysis of the ABC genes in the oriental fruit fly, Bactrocera dorsalis (Hendel). We identified a total of 47 ABC genes (BdABCs) from the transcriptomic and genomic databases of B. dorsalis and classified these genes into eight subfamilies (A-H), including 7 ABCAs, 7 ABCBs, 9 ABCCs, 2 ABCDs, 1 ABCE, 3 ABCFs, 15 ABCGs, and 3 ABCHs. Comparative phylogenetic analysis of the ABCs suggests an orthologous relationship between B. dorsalis and other insect species in which these genes have been related to pesticide resistance and essential biological processes. Comparison of transcriptome and relative expression patterns of BdABCs indicated diverse multifunctions within different B. dorsalis tissues. The expression of 4, 10, and 14 BdABCs from 18 BdABCs was significantly upregulated after exposure to LD50s of malathion, avermectin, and beta-cypermethrin, respectively. The maximum expression level of most BdABCs (including BdABCFs, BdABCGs, and BdABCHs) occurred at 48h post exposures, whereas BdABCEs peaked at 24h after treatment. Furthermore, RNA interference-mediated suppression of BdABCB7 resulted in increased toxicity of malathion against B. dorsalis. These data suggest that ABC transporter genes might play key roles in xenobiotic metabolism and biosynthesis in B. dorsalis.