Challenges and Countermeasures of Teachers’ Professional Development from the Perspective of Globalization

Under the influence of globalization, the intensification of international competition is in the final analysis the competition of education and talents. Teachers are the main body of teaching activities. Teachers’ professionalization is an important symbol to measure a country’s educational level. At present, the professional development of teachers in China is facing enormous challenges. In terms of concept, system and the allocation and utilization of educational resources, there are great problems. In order to meet the needs of teachers’ professional development in the perspective of globalization, the new era should promote the upgrading of teachers’ professional level from the aspects of renewal of ideas, improvement of system guarantee system, diversified development and integration and distribution of resources

Electrical dual-percolation in MWCNTs/SBS/PVDF based thermoplastic elastomer (TPE) composites and the effect of mechanical stretching

Dielectric thermoplastic elastomers (TPEs) offer a number of advantages over traditional dielectric elastomers or rubbers in terms of tailorable mechanical and electrical properties, higher mechanical strain, and ease of processing and shaping. Such a combination of properties has attracted increasing attention in flexible energy harvesting and storage applications. The combination of styrene–butadiene-styrene (SBS) and poly(vinylidene fluoride) (PVDF) has the potential to provide a combination of high elongation to break and increased relative permittivity, however the immiscibility between SBS and PVDF results in polymer blends with poor stretchability and processing properties. In this work, a dual percolated structure was created in a thermoplastic elastomer of SBS/PVDF (50/50 wt%), by coupling EVA as a compatibiliser for SBS/PVDF with multi-walled carbon nanotubes (MWCNTs) as a conductive filler that created an electrical percolation network. The elongation at break of SBS/PVDF was significantly enhanced by adding 20 wt% of EVA due to the reduced phase dimensions and enhanced interfacial adhesion. The addition of MWCNTs enabled the formation of a percolated network at 1 wt% in the SBS phase, followed by a second percolation at 3 wt% in both PVDF and SBS phases. The relative permittivity of the composite increased to 22.5 at 1 wt% MWCNT with a tan δ of 0.5, and further increased to 34.9 for a 2 wt% of MWCNT concentration while the tan δ remained constant. In-situ electrical testing for the SBS/PVDF thermoplastic elastomer under strain showed that, at 1 wt% MWCNT, the non-percolated PVDF islands acted as variable capacitors whose capacitance increased with degree of stretching. For the dual percolated structure formed at 3 wt% MWCNT, the capacitance and conductivity of the composites were unaffected up to 30% strain. The high relative permittivity and strains of over 100% means that the SBS/PVDF based thermoplastic elastomer is readily suitable for vibration control sensors, variable impedance devices, energy harvesters and artificial muscles and actuators

Imprint of the stochastic nature of photon emission by electrons on the proton energy spectra in the laser-plasma interaction

The impact of stochasticity effects (SEs) in photon emissions on the proton energy spectra during laser-plasma interaction is theoretically investigated in the quantum radiation-dominated regime, which may facilitate SEs experimental observation. We calculate the photon emissions quantum mechanically and the plasma dynamics semiclassically via two-dimensional particle-in-cell simulations. An ultrarelativistic plasma generated and driven by an ultraintense laser pulse head-on collides with another strong laser pulse, which decelerates the electrons due to radiation-reaction effect and results in a significant compression of the proton energy spectra because of the charge separation force. In the considered regime the SEs are demonstrated in the shift of the mean energy of the protons up to hundreds of MeV. This effect is robust with respect to the laser and target parameters and measurable in soon available strong laser facilities

TCF1 and LEF1 Control Treg Competitive Survival and Tfr Development to Prevent Autoimmune Diseases.

CD4+ Foxp3+ T regulatory (Treg) cells are key players in preventing lethal autoimmunity. Tregs undertake differentiation processes and acquire diverse functional properties. However, how Treg's differentiation and functional specification are regulated remains incompletely understood. Here, we report that gradient expression of TCF1 and LEF1 distinguishes Tregs into three distinct subpopulations, particularly highlighting a subset of activated Treg (aTreg) cells. Treg-specific ablation of TCF1 and LEF1 renders the mice susceptible to systemic autoimmunity. TCF1 and LEF1 are dispensable for Treg's suppressive capacity but essential for maintaining a normal aTreg pool and promoting Treg's competitive survival. As a consequence, the development of T follicular regulatory (Tfr) cells, which are a subset of aTreg, is abolished in TCF1/LEF1-conditional knockout mice, leading to unrestrained T follicular helper (Tfh) and germinal center B cell responses. Thus, TCF1 and LEF1 act redundantly to control the maintenance and functional specification of Treg subsets to prevent autoimmunity

Ultralong nitrogen/sulfur Co‐doped carbon nano‐hollow‐sphere chains with encapsulated cobalt nanoparticles for highly efficient oxygen electrocatalysis

The development of simple and effective strategies to prepare electrocatalysts, which possess unique and stable structures comprised of metal/nonmetallic atoms for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), is currently an urgent issue. Herein, an efficient bifunctional electrocatalyst featured by ultralong N, S-doped carbon nano-hollow-sphere chains about 1300 nm with encapsulated Co nanoparticles (Co-CNHSCs) is developed. The multifunctional catalytic properties of Co together with the heteroatom-induced charge redistribution (i.e., modulating the electronic structure of the active site) result in superior catalytic activities toward OER and ORR in alkaline media. The optimized catalyst Co-CNHSC-3 displays an outstanding electrocatalytic ability for ORR and OER, a high specific capacity of 1023.6 mAh gZn−1, and excellent reversibility after 80 h at 10 mA cm−2 in a Zn-air battery system. This work presents a new strategy for the design and synthesis of efficient multifunctional carbon-based catalysts for energy storage and conversion devices

Complete mitochondrial genomes of Taenia multiceps, T. hydatigena and T. pisiformis: additional molecular markers for a tapeworm genus of human and animal health significance

<p>Abstract</p> <p>Background</p> <p>Mitochondrial genomes provide a rich source of molecular variation of proven and widespread utility in molecular ecology, population genetics and evolutionary biology. The tapeworm genus <it>Taenia </it>includes a diversity of tapeworm parasites of significant human and veterinary importance. Here we add complete sequences of the mt genomes of <it>T. multiceps</it>, <it>T. hydatigena </it>and <it>T. pisiformis</it>, to a data set of 4 published mtDNAs in the same genus. Seven complete mt genomes of <it>Taenia </it>species are used to compare and contrast variation within and between genomes in the genus, to estimate a phylogeny for the genus, and to develop novel molecular markers as part of an extended mitochondrial toolkit.</p> <p>Results</p> <p>The complete circular mtDNAs of <it>T. multiceps</it>, <it>T. hydatigena </it>and <it>T. pisiformis </it>were 13,693, 13,492 and 13,387 bp in size respectively, comprising the usual complement of flatworm genes. Start and stop codons of protein coding genes included those found commonly amongst other platyhelminth mt genomes, but the much rarer initiation codon GTT was inferred for the gene <it>atp</it>6 in <it>T. pisiformis</it>. Phylogenetic analysis of mtDNAs offered novel estimates of the interrelationships of <it>Taenia</it>. Sliding window analyses showed <it>nad</it>6, <it>nad</it>5, <it>atp</it>6, <it>nad</it>3 and <it>nad</it>2 are amongst the most variable of genes per unit length, with the highest peaks in nucleotide diversity found in <it>nad</it>5. New primer pairs capable of amplifying fragments of variable DNA in <it>nad</it>1, <it>rrn</it>S and <it>nad</it>5 genes were designed <it>in silico </it>and tested as possible alternatives to existing mitochondrial markers for <it>Taenia</it>.</p> <p>Conclusions</p> <p>With the availability of complete mtDNAs of 7 <it>Taenia </it>species, we have shown that analysis of amino acids provides a robust estimate of phylogeny for the genus that differs markedly from morphological estimates or those using partial genes; with implications for understanding the evolutionary radiation of important <it>Taenia</it>. Full alignment of the nucleotides of <it>Taenia </it>mtDNAs and sliding window analysis suggests numerous alternative gene regions are likely to capture greater nucleotide variation than those currently pursued as molecular markers. New PCR primers developed from a comparative mitogenomic analysis of <it>Taenia </it>species, extend the use of mitochondrial markers for molecular ecology, population genetics and diagnostics.</p