Current Situation, Problems and Countermeasures of Admittance Policy for Chinese Teacher Educators

Teacher education greatly safeguards the teacher resources and quality of elementary education. Teacher educators directly undertake teacher education. The level of their recruitment standards usually determines the level of teacher education. This paper describes and comments on China’s current policies on the recruitment of teacher educators, analyzes main problems and then put forward corresponding suggestions on these policies

Optimal Modeled Six-Phase Space Vector Pulse Width Modulation Method for Stator Voltage Harmonic Suppression

Dual Y shift 30 six-phase motors are expected to be extensively applied in high-power yet energy-effective fields, and a harmonic-suppressing control strategy plays a vital role in extending their prominent features of low losses and ultra-quiet operation. Aiming at the suppression of harmonic voltages, this paper proposes a six-phase space vector pulse width modulation method based on an optimization model, namely OM-SVPWM. First, four adjacent large vectors are employed in each of 12 sectors on a fundamental sub-plane. Second, the optimization model is constructed to intelligently determine activation durations of the four vectors, where its objective function aims to minimize the synthesis result on a harmonic sub-plane, and its constraint condition is that the synthesis result on the fundamental sub-plane satisfies a reference vector. Finally, to meet the real-time requirement, optimum solutions are obtained by using general central path following algorithm (GCPFA). Simulation and experiment results prove that, the OM-SVPWM performs around 37% better than a state-of-the-art competitive SVPWM in terms of harmonics suppression, which promise the proposed OM-SVPWM conforms to the energy-effective direction in actual engineering applications.Peer reviewe

Peiminine regulates the biological characteristics of colorectal cancer cells via P13K/Akt/mTOR and oxidative stress pathways

Purpose: To investigate the influence of peiminine on biological characteristics of colorectal cancer cells, and the underlying mechanism.Methods: Two groups of cultured human colorectal cancer HCT-116 cells were used: peiminine and control groups. Peiminine group cells were exposed to the drug at a final concentration of 100 μmol/L. The effect of peiminine on cell proliferation was determined with CCK-8 method, while its effect on apoptosis was determined with flow cytometric method. Cell migration was determined with scratch test. The effect of peiminine on the expressions of proteins associated with the P13K/Akt/mTOR pathway and Wnt/β-catenin pathway in HCT-116 cells was determined with Western blotting assay.Results: Cell proliferation was markedly reduced in the peiminine group, relative to control (p < 0.05). There was higher percentage cell apoptosis in peiminine-treated cells than in control. Moreover, cell migration potential was significantly lower in the peiminine-treated cells. There were significantly downregulated levels of p-P13K, p-Akt and p-mTOR expressions in peiminine group, relative to the corresponding control expressions (p < 0.05). However, there were significantly higher relative expression of Wnt in peiminine group than in control cells, but β-catenin level was reduced, relative to the corresponding control level (p < 0.05).Conclusion: These data indicate that peiminine suppresses the proliferative, apoptotic and migratory potential of colorectal carcinoma HCT-116 cells via regulation of P13K/Akt/mTOR and oxidative stress pathways

Dynamic interactions of a conserved enterotoxigenic Escherichia coli adhesin with intestinal mucins govern epithelium engagement and toxin delivery

At present, there is no vaccine for enterotoxigenic Escherichia coli (ETEC), an important cause of diarrheal illness. Nevertheless, recent microbial pathogenesis studies have identified a number of molecules produced by ETEC that contribute to its virulence and are novel antigenic targets to complement canonical vaccine approaches. EtpA is a secreted two-partner adhesin that is conserved within the ETEC pathovar. EtpA interacts with the tips of ETEC flagella to promote bacterial adhesion, toxin delivery, and intestinal colonization by forming molecular bridges between the bacteria and the epithelial surface. However, the nature of EtpA interactions with the intestinal epithelium remains poorly defined. Here, we demonstrate that EtpA interacts with glycans presented by transmembrane and secreted intestinal mucins at epithelial surfaces to facilitate pathogen-host interactions that culminate in toxin delivery. Moreover, we found that a major effector molecule of ETEC, the heat-labile enterotoxin (LT), may enhance these interactions by stimulating the production of the gel-forming mucin MUC2. Our studies suggest, however, that EtpA participates in complex and dynamic interactions between ETEC and the gastrointestinal mucosae in which host glycoproteins promote bacterial attachment while simultaneously limiting the epithelial engagement required for effective toxin delivery. Collectively, these data provide additional insight into the intricate nature of ETEC interactions with the intestinal epithelium that have potential implications for rational approaches to vaccine design

Genome-Wide Association Study for Plant Height and Grain Yield in Rice under Contrasting Moisture Regimes

Drought is one of the vitally critical environmental stresses affecting both growth and yield potential in rice. Drought resistance is a complicated quantitative trait that is regulated by numerous small effect loci and hundreds of genes controlling various morphological and physiological responses to drought. For this study, 270 rice landraces and cultivars were analyzed for their drought resistance. This was done via determination of changes in plant height and grain yield under contrasting water regimes, followed by detailed identification of the underlying genetic architecture via genome-wide association study (GWAS). We controlled population structure by setting top two eigenvectors and combining kinship matrix for GWAS in this study. Eighteen, five, and six associated loci were identified for plant height, grain yield per plant, and drought resistant coefficient, respectively. Nine known functional genes were identified, including five for plant height (OsGA2ox3, OsGH3-2, sd-1, OsGNA1 and OsSAP11/OsDOG), two for grain yield per plant (OsCYP51G3 and OsRRMh) and two for drought resistant coefficient (OsPYL2 and OsGA2ox9), implying very reliable results. A previous study reported OsGNA1 to regulate root development, but this study reports additional controlling of both plant height and root length. Moreover, OsRLK5 is a new drought resistant candidate gene discovered in this study. OsRLK5 mutants showed faster water loss rates in detached leaves. This gene plays an important role in the positive regulation of yield-related traits under drought conditions. We furthermore discovered several new loci contributing to the three investigated traits (plant height, grain yield, and drought resistance). These associated loci and genes significantly improve our knowledge of the genetic control of these traits in rice. In addition, many drought resistant cultivars screened in this study can be used as parental genotypes to improve drought resistance of rice by molecular breeding

The Seismic Acquisition Method Researching for the Complex Mountainous Terrain in YXL Area Qaidam Basin

YXL area is the concentration area of exploration activity with classic complicate surface feature in Qaidam Basin. So, its interference wave is development and the seismic data is in low signal-to-noise ratio (SNR) in the area. Through multiple seismic exploration collecting means, Acquisition techniques has obtained great breakthrough, and array technique has showed great affection. The geological tasks and seismic exploration difficulties of target area is aimed in the paper. The remained problems in the past seismic exploration is dissected, studying the noise interference feature and the effects for the array noise attenuation. And the positive roles of the stack response for the noise attenuation is discussed and to supply the high quality and the high precision data for the seismic in this area.Key words: Shot-receiving array; Stack array response; Geometry; Direction effect; Array weighted average effect; Signal-to-noise rati

Genetic dissection of rice grain shape using a recombinant inbred line population derived from two contrasting parents and fine mapping a pleiotropic quantitative trait locus qGL7

<p>Abstract</p> <p>Background</p> <p>The three-dimensional shape of grain, measured as grain length, width, and thickness (GL, GW, and GT), is one of the most important components of grain appearance in rice. Determining the genetic basis of variations in grain shape could facilitate efficient improvements in grain appearance. In this study, an F_7:8recombinant inbred line population (RIL) derived from a cross between <it>indica </it>and <it>japonica </it>cultivars (Nanyangzhan and Chuan7) contrasting in grain size was used for quantitative trait locus (QTL) mapping. A genetic linkage map was constructed with 164 simple sequence repeat (SSR) markers. The major aim of this study was to detect a QTL for grain shape and to fine map a minor QTL, <it>qGL7</it>.</p> <p>Results</p> <p>Four QTLs for GL were detected on chromosomes 3 and 7, and 10 QTLs for GW and 9 QTLs for GT were identified on chromosomes 2, 3, 5, 7, 9 and 10, respectively. A total of 28 QTLs were identified, of which several are reported for the first time; four major QTLs and six minor QTLs for grain shape were also commonly detected in both years. The minor QTL, <it>qGL7</it>, exhibited pleiotropic effects on GL, GW, GT, 1000-grain weight (TGW), and spikelets per panicle (SPP) and was further validated in a near isogenic F₂population (NIL-F₂). Finally, <it>qGL7 </it>was narrowed down to an interval between InDel marker RID711 and SSR marker RM6389, covering a 258-kb region in the Nipponbare genome, and cosegregated with InDel markers RID710 and RID76.</p> <p>Conclusion</p> <p>Materials with very different phenotypes were used to develop mapping populations to detect QTLs because of their complex genetic background. Progeny tests proved that the minor QTL, <it>qGL7</it>, could display a single mendelian characteristic. Therefore, we suggested that minor QTLs for traits with high heritability could be isolated using a map-based cloning strategy in a large NIL-F₂population. In addition, combinations of different QTLs produced diverse grain shapes, which provide the ability to breed more varieties of rice to satisfy consumer preferences.</p