Forced waves and their asymptotic behaviors in a Lotka-Volterra competition model with spatio-temporal nonlocal effect under climate change

In this paper, we propose a modified Lotka-Volterra competition model under climate change, which incorporates both spatial and temporal nonlocal effect. First, the theoretical analyses for forced waves of the model are performed, and the existence of the forced waves is proved by using the cross-iteration scheme combining with appropriate upper and lower solutions. Second, the asymptotic behaviors of the forced waves are derived by using the linearization and limiting method, and we find that the asymptotic behaviors of forced waves are mainly determined by the leading equations. In addition, some typical numerical examples are provided to illustrate the analytical results. By choosing three kinds of different kernel functions, it is found that the forced waves can be both monotonic and non-monotonic

Facile synthesis of coaxial CNTs/MnOx-carbon hybrid nanofibers and their greatly enhanced lithium storage performance

Carbon nanotubes (CNTs)/MnOx-Carbon hybrid nanofibers have been successfully synthesized by the combination of a liquid chemical redox reaction (LCRR) and a subsequent carbonization heat treatment. The nanostructures exhibit a unique one-dimensional core/shell architecture, with one-dimensional CNTs encapsulated inside and a MnOx-carbon composite nanoparticle layer on the outside. The particular porous characteristics with many meso/micro holes/pores, the highly conductive one-dimensional CNT core, as well as the encapsulating carbon matrix on the outside of the MnOx nanoparticles, lead to excellent electrochemical performance of the electrode. The CNTs/MnOx-Carbon hybrid nanofibers exhibit a high initial reversible capacity of 762.9 mAh-1, a high reversible specific capacity of 560.5 mAh-1 after 100 cycles, and excellent cycling stability and rate capability, with specific capacity of 396.2 mAh-1 when cycled at the current density of 1000 mA-1, indicating that the CNTs/MnOx-Carbon hybrid nanofibers are a promising anode candidate for Li-ion batteries

A combined hydrogen storage system of Mg(BH4)(2)-LiNH2 with favorable dehydrogenation

The decomposition properties of Mg(BH4)2−LiNH2 mixtures were investigated. Apparent NH3 release appeared from 50 to 300 °C for the Mg(BH4)2−LiNH2 mixtures with mole ratios of 1:1.5, 1:2, and 1:3, while only hydrogen release was detected for the mixture with a mole ratio of 1:1. In the case of the Mg(BH4)2−LiNH2 (1:1) sample, the onset of the first-step dehydrogenation starts at 160 °C, with a weight loss of 7.2 wt % at 300 °C, which is improved significantly compared to the pure Mg(BH4)2 alone. From Kissinger’s method, the activation energy, Ea, for the first and second step dehydrogenation in Mg(BH4)2−LiNH2 (1:1) was estimated to be about 121.7 and 236.6 kJ mol−1, respectively. The improved dehydrogenation in the combined system may be ascribed to a combination reaction between [BH4] and [NH2], resulting in the formation of Li−Mg alloy and amorphous B−N compound

Preparation of TiO2(B) @anatase hybrid nanowires and their lithium storage properties

Novel anatase@TiO2(B) hybrid nanowires have been synthesized by a facile aqueous alkali hydrothermal method, followed by acid washing and heating. The nanowires have a bicrystalline structure consisting of a TiO2(B) core encapsulated in an anatase shell. This hybrid nanowire has one column of entangled interface between the (001) plane of anatase and the (100) plane of TiO2(B), where a high conductivity column layer or belt comes into being, owing to the one way transfer of electron-hole carriers during the heterojunction formation. The as-prepared anatase@TiO2(B) hybrid nanowires deliver a highly reversible capacity of 196 mAhg-1 after 100 cycles at 30 mAg-1 (0.1C) and excellent rate capability as high as 125 mAhg-1 when cycled at 4500 mAg-1 (15C). Owing to the excellent electrochemical performance, anatase@TiO2(B) hybrid nanowires could be promising anode materials for lithium ion batteries

TiO2(B)@carbon composite nanowires as anode for lithium ion batteries with enhanced reversible capacity and cyclic performance

Novel TiO2(B)@carbon composite nanowires were simply prepared by a two-step hydrothermal process with subsequent heat treatment in argon. The nanostructures exhibit the unique feature of having TiO2(B) encapsulated inside and an amorphous carbon layer coating the outside. The unique core/shell structure and chemical composition is likely to lead to perfect performance in many applications. In this paper, the results of Li-ion battery testing are presented to demonstrate the superior cyclic performance and rate capability of the TiO2(B)@carbon nanowires. The composite nanowires exhibit a high reversible capacity of 560 mAh g−1 after 100 cycles at the current density of 30 mA g−1, and excellent cycling stability and rate capability (200 mAh g−1 when cycled at the current density of 750 mA g−1), indicating that the composite is a promising anode candidate for Li-ion batteries

Dispersion of SnO2 nanocrystals on TiO2(B) nanowires as anode material for lithium ion battery applications

TiO2(B)@SnO2 core–shell hybrid nanowires have been synthesized by a facile hydrothermal process and subsequent liquid phase reaction. Hybrid nanowire electrodes exhibit excellent reversible lithium storage capacity rate capability and good cyclability, mainly due to the particular architecture of the composite, which features an open continuous channel along its axis, facilitating lithium ion diffusion, and provides effective mechanical support for the TiO2(B) core, alleviating the stress produced during discharge–charge cycling and also preventing the pulverization of the Sn nanoparticles. Owing to its superior electrochemical performance, this composite could be a promising potential anode material for lithium ion batteries

Easy preparation of SnO2@carbon composite nanofibers with improved lithium ion storage properties

SnO2@carbon nanofibers were synthesized by a combination of electrospinning and subsequent thermal treatments in air and then in argon to demonstrate their potential use as an anode material in lithium ion battery applications. The as-prepared SnO2@carbon nanofibers consist of SnO2 anoparticles/nanocrystals encapsulated in a carbon matrix and contain many mesopores. Because of the charge pathways, both for the electrons and the lithium ions, and the buffering function provided by both the carbon encapsulating the SnO2 nanoparticles and the mesopores, which tends to alleviate the volumetric effects during the charge/discharge cycles, the nanofibers display a greatly improved reversible capacity of 420 mAh/g after 100 cycles at a constant current of 100 mA/g, and a sharply enhanced reversible capacity at higher rates (0.5, 1, and 2 C) compared with pure SnO2 nanofibers, which makes it a promising anode material for lithium ion batteries

Synthesis of uniform TiO2@carbon composite nanofibers as anode for lithium ion batteries with enhanced electrochemical performance

Very large area, uniform TiO2@carbon composite nanofibers were easily prepared by thermal pyrolysis and oxidization of electrospun titanium(IV) isopropoxide/polyacrylonitrile (PAN) nanofibers in argon. The composite nanostructures exhibit the unique feature of having TiO2 nanocrystals encapsulated inside a porous carbon matrix. The unique orderly-bonded nanostructure, porous characteristics, and highly conductive carbon matrix favour excellent electrochemical performance of the TiO2@carbon nanofiber electrode. The TiO2@carbon hybrid nanofibers exhibited highly reversible capacity of 206 mAh g−1 up to 100 cycles at current density of 30 mA g−1 and excellent cycling stability, indicating that the composite is a promising anode candidate for Li-ion batteries

Development of a circHIPK3-based ceRNA network and identification of mRNA signature in breast cancer patients harboring BRCA mutation

Background Exploring the regulatory network of competing endogenous RNAs (ceRNAs) as hallmarks for breast cancer development has great significance and could provide therapeutic targets. An mRNA signature predictive of prognosis and therapy response in BRCA carriers was developed according to circular RNA homeodomain-interacting protein kinase 3 (circHIPK3)-based ceRNA network. Method We constructed a circHIPK3-based ceRNA network based on GSE173766 dataset and identified potential mRNAs that were associated with BRCA mutation patients within this ceRNA network. A total of 11 prognostic mRNAs and a risk model were identified and developed by univariate Cox regression analysis and the LASSO regression analysis as well as stepAIC method. Genomic landscape was treated by mutect2 and fisher. Immune characteristics was analyzed by ESTIMATE, MCP-counter. TIDE analysis was conducted to predict immunotherapy. The clinical treatment outcomes of BRCA mutation patients were assessed using a nomogram. The proliferation, migration and invasion in breast cancer cell lines were examined using CCK8 assay and transwell assay. Result We found 241 mRNAs within the circHIPK3-based ceRNA network. An 11 mRNA-based signature was identified for prognostic model construction. High risk patients exhibited dismal prognosis, low response to immunotherapy, less immune cell infiltration and tumor mutation burden (TMB). High-risk patients were sensitive to six anti-tumor drugs, while low-risk patient were sensitive to 47 drugs. The risk score was the most effective on evaluating patients’ survival. The robustness and good prediction performance were validated in The Cancer Genome Atlas (TCGA) dataset and immunotherapy datasets, respectively. In addition, circHIPK3 mRNA level was upregulated, and promoted cell viability, migration and invasion in breast cancer cell lines. Conclusion The current study could improve the understanding of mRNAs in relation to BRCA mutation and pave the way to develop mRNA-based therapeutic targets for breast cancer patients with BRCA mutation