Single-Crystalline Bilayered V₂O₅ Nanobelts for High-Capacity Sodium-Ion Batteries

Single-crystalline bilayered vanadium oxide nanobelts were synthesized by a simple solvothermal method. FESEM and AFM analyses identified the nanobelt morphology of the as-prepared vanadium oxide with a rectangular cross-section and a thickness of approximately 50 nm. XRD and TEM characterizations revealed the presence of a large (001) interlayer spacing (∼11.53 Å), which can accommodate Na-ion insertion and extraction. When applied as cathode materials in Na-ion batteries, vanadium oxide nanobelts exhibited a high capacity of 231.4 mA h g^–1 at a current density of 80 mA g^–1. This corresponds to the theoretical capacity to form Na₂V₂O₅ on Na-ion insertion. Vanadium oxide nanobelts also demonstrated an excellent high-rate performance and a satisfactory cyclability. These superior electrochemical performances could be ascribed to the unique bilayered vanadium oxide nanobelts with dominantly exposed {100} crystal planes, which provide large interlayer spacing for facile Na-ion insertion/extraction. Single-crystalline bilayered vanadium oxide nanobelts could be promising cathode materials for high-performance Na-ion batteries

Anatase TiO₂: Better Anode Material Than Amorphous and Rutile Phases of TiO₂ for Na-Ion Batteries

Amorphous TiO₂@C nanospheres were synthesized via a template approach. After being sintered under different conditions, two types of polyphase TiO₂ hollow nanospheres were obtained. The electrochemical properties of the amorphous TiO₂ nanospheres and the TiO₂ hollow nanospheres with different phases were characterized as anodes for the Na-ion batteries. It was found that all the samples demonstrated excellent cyclability, which was sustainable for hundreds of cycles with little capacity fading, although the anatase TiO₂ presented a capability that was better than that of the mixed anatase/rutile TiO₂ or the amorphous TiO₂@C. Through crystallographic analysis, it was revealed that the anatase TiO₂ crystal structure supplies two-dimensional diffusion paths for Na-ion intercalation and more accommodation sites. Density functional theory calculations indicated lower energy barriers for the insertion of Na⁺ into anatase TiO₂. Therefore, anatase TiO₂ hollow nanospheres show excellent high-rate performance. Through <i>ex situ</i> field emission scanning electron microscopy, it was revealed that the TiO₂ hollow nanosphere architecture can be maintained for hundreds of cycles, which is the main reason for its superior cyclability

Transcriptome Sequencing Analysis and Functional Identification of Sex Differentiation Genes from the Mosquito Parasitic Nematode, <i>Romanomermis wuchangensis</i>

<div><p>Mosquito-transmitted diseases like malaria and dengue fever are global problem and an estimated 50–100 million of dengue or dengue hemorrhagic fever cases are reported worldwide every year. The mermithid nematode <i>Romanomermis wuchangensis</i> has been successfully used as an ecosystem-friendly biocontrol agent for mosquito prevention in laboratory studies. However, this nematode can not undergo sex differentiation in <i>vitro</i> culture, which has seriously affected their application of biocontrol in the field. In this study, based on transcriptome sequencing analysis of <i>R</i>. <i>wuchangensis</i>, <i>Rwucmab-3</i>, <i>Rwuclaf-1</i> and <i>Rwuctra-2</i> were cloned and used to investigate molecular regulatory function of sex differentiation. qRT-PCR results demonstrated that the expression level of <i>Rwucmab-3</i> between male and female displayed obvious difference on the 3^rd day of parasitic stage, which was earlier than <i>Rwuclaf-1</i> and <i>Rwuctra-2</i>, highlighting sex differentiation process may start on the 3^rd day of parasitic stage. Besides, FITC was used as a marker to test dsRNA uptake efficiency of <i>R</i>. <i>wuchangensis</i>, which fluorescence intensity increased with FITC concentration after 16 h incubation, indicating this nematode can successfully ingest soaking solution via its cuticle. RNAi results revealed the sex ratio of <i>R</i>. <i>wuchangensis</i> from RNAi treated groups soaked in dsRNA of <i>Rwucmab-3</i> was significantly higher than <i>gfp</i> dsRNA treated groups and control groups, highlighting RNAi of <i>Rwumab-3</i> may hinder the development of male nematodes. These results suggest that <i>Rwucmab-3</i> mainly involves in the initiation of sex differentiation and the development of male sexual dimorphism. <i>Rwuclaf-1</i> and <i>Rwuctra-2</i> may play vital role in nematode reproductive and developmental system. In conclusion, transcript sequences presented in this study could provide more bioinformatics resources for future studies on gene cloning and other molecular regulatory mechanism in <i>R</i>. <i>wuchangensis</i>. Moreover, identification and functional analysis of sex differentiation genes may clarify the sex differentiation mechanism of <i>R</i>. <i>wuchangensis</i>, which are helpful to solve the uncompleted sex differentiation problem in <i>vitro</i> culture and the potential large-scale field application controlling the larvae of <i>C</i>. <i>quinquefasciatus</i>, <i>A</i>. <i>aegypti</i> and <i>A</i>. <i>albopictus</i>.</p></div

Primers used in the experiments.

<p>Primers used in the experiments.</p

FITC fluorescence of <i>R</i>. <i>wuchangensis</i> incubated in RNase-free water.

<p>Images in Figures A-J show FITC fluorescence of <i>R</i>. <i>wuchangensis</i> incubated for 16 h with different concentrations of FITC: A = 20 μg/mL; B = 40 μg/mL; C = 60 μg/mL; D = 80 μg/mL; E = 100 μg/mL; F = 200 μg/mL; G = 400 μg/mL; H = 600 μg/mL; I = 800 μg/mL; J = 1000 μg/mL. Scale bar represents 50 μm.</p

Cloning and expression analysis of the DEAD-box/RNA helicase <i>Oslaf-1</i> in <i>Ovomermis sinensis</i> - Fig 10

<p>Sex ratio displayed (A) and relative mRNA expression level (B) by <i>O</i>. <i>sinensis</i> following soaking for 16 h in dsRNA of <i>Oslaf-1</i> (*P < 0.05, **P < 0.01, ***P < 0.001).</p

Overview of the sequencing reads.

<p>Overview of the sequencing reads.</p

The distribution of OsLAF-1 in various parts of <i>O</i>. <i>sinensis</i>.

<p>Columns: 1: head; 2: tail; 3: testis; 4: ovary; 5: integument.</p

The ISH result of embryos of <i>O</i>. <i>sinensis</i> in different stages.

<p>A: unicellular stage; B: blastula stage; C: gastrula stage; D: juvenile I stage; E: pre-parasitic juvenile stage; F: control (blastula stage). Note: Picture A-D, F (40 × magnification), E (1 × magnification).</p

Nucleotide and deduced amino acid sequences of <i>Oslaf-1</i>.

<p>Nucleotides and amino acids are numbered along the right margin; the start codon, stop codon, and the plus tail signal ATTAAA are underlined; the DEAD-box domains are contained within the rectangles.</p