55 research outputs found
Wheat powdery mildew resistance: from gene identification to immunity deployment
Powdery mildew is one of the most devastating diseases on wheat and is caused by the obligate biotrophic phytopathogen Blumeria graminis f. sp. tritici (Bgt). Due to the complexity of the large genome of wheat and its close relatives, the identification of powdery mildew resistance genes had been hampered for a long time until recent progress in large-scale sequencing, genomics, and rapid gene isolation techniques. Here, we describe and summarize the current advances in wheat powdery mildew resistance, emphasizing the most recent discoveries about the identification of genes conferring powdery mildew resistance and the similarity, diversity and molecular function of those genes. Multilayered resistance to powdery mildew in wheat could be used for counteracting Bgt, including durable, broad spectrum but partial resistance, as well as race-specific and mostly complete resistance mediated by nucleotide-binding and leucine rich repeat domain (NLR) proteins. In addition to the above mentioned layers, manipulation of susceptibility (S) and negative regulator genes may represent another layer that can be used for durable and broad-spectrum resistance in wheat. We propose that it is promising to develop effective and durable strategies to combat powdery mildew in wheat by simultaneous deployment of multilayered immunity
A Finger Vein Feature Extraction Method Incorporating Principal Component Analysis and Locality Preserving Projections
In the field of biometric recognition, finger vein recognition has received widespread attention by virtue of its advantages, such as biopsy, which is not easy to be stolen. However, due to the limitation of acquisition conditions such as noise and illumination, as well as the limitation of computational resources, the discriminative features are not comprehensive enough when performing finger vein image feature extraction. It will lead to such a result that the accuracy of image recognition cannot meet the needs of large numbers of users and high security. Therefore, this paper proposes a novel feature extraction method called principal component local preservation projections (PCLPP). It organically combines principal component analysis (PCA) and locality preserving projections (LPP) and constructs a projection matrix that preserves both the global and local features of the image, which will meet the urgent needs of large numbers of users and high security. In this paper, we apply the Shandong University homologous multi-modal traits (SDUMLA-HMT) finger vein database to evaluate PCLPP and add “Salt and pepper” noise to the dataset to verify the robustness of PCLPP. The experimental results show that the image recognition rate after applying PCLPP is much better than the other two methods, PCA and LPP, for feature extraction
Analysis of Evolution Mechanism and Optimal Reward-Penalty Mechanism for Collection Strategies in Reverse Supply Chains: The Case of Waste Mobile Phones in China
The aim of this paper is to discuss the coopetition (cooperative competition) relationship between a manufacturer and a collector in the collection of waste mobile phones (WMPs) and examine the evolution mechanism and the internal reward-penalty mechanism (RPM) for their collection strategies. A coopetition evolutionary game model based on evolutionary game theory was developed to obtain their common and evolutional collection strategies. The pure-strategy Nash equilibriums of this model were obtained which showed their collection strategy choices of perfect competition or cooperation. The mixed strategy Nash equilibrium was obtained which revealed evolution trends and laws. In addition, the optimal RPM was obtained in the sensitivity analysis of related parameters. The example of WMPs in China was taken to examine the simulation of the RPM. Results show that (i) although the manufacturer and the collector may change their strategies of cooperation and competition over time, cooperation is their best choice to increase payoffs; (ii) the optimal RPM is beneficial to propel their cooperation tendency and then to increase their payoffs
Decisions of the Dual-Channel Supply Chain under Double Policy Considering Remanufacturing
Considering the preference of green consumers for remanufactured products, a dual-sale-channel supply chain model with government non-intervention, government remanufacturing subsidy policy, and carbon tax policy is constructed, respectively. The difference of the optimal decision between the firm and the government under the two policies is discussed in this paper. Meanwhile, we analyze the influence of green consumers on the government’s optimal decision, based on social welfare maximization. It is found that without government intervention, social welfare is the lowest. The carbon tax policy is better when the proportion of green consumers and the environmental coefficient are extreme or moderate at the same time. Otherwise, the subsidy policy is better. The carbon tax policy is more effective than the subsidy policy in controlling carbon emissions. Profit-sharing contracts should be established by enterprises and governments to achieve win⁻win results
Effects of Ru on Microstructure and Stress Ruputure Property of Ni-based Single Crystal Superalloy DD22
The effects of Ru on the as-cast, heat-treated microstructures and stress rupture properties under 1100-1150 ℃ were investigated in new generation Ni-based single crystal superalloys DD22 with two levels of Ru (0% and 2%, mass fraction) additions. The results indicate that the addition of Ru results in the decrease of the solidus and liquidus temperatures, the volume fraction of (γ+γ') eutectic as well as solidification segregation. The size of γ' phase and elemental partitioning ratio of Re and Cr which are important for the precipitation of TCP phase decreases after heat treatment with Ru addition. Ru addition decreases the size of γ' phase, increases γ/γ' misfit and solution strengthening effect and inhibits the precipitation of TCP phase in the process of stress rupture loading, which finally improve the stress rupture properties of DD22 alloy significantly
Pricing Decision for Reverse Logistics System under Cross-Competitive Take-Back Mode Based on Game Theory
Considering the reverse logistics system composed of two manufacturers and two recyclers under the cross-competitive take-back mode, which is influenced by multiple factors (industry competition, economies of scale, government subsidies, remanufacturing rate, etc.), a model for remanufacturing reverse logistics system based on Stackelberg game is established. Then, the Nash equilibrium solution of decision variables is solved to obtain the best profit of all participants under the cross-competitive take-back mode. Furthermore, the parameter constraint analysis is carried out, and the monopolistic take-back mode is introduced for comparative analysis. Then, the sensitivity analysis of the model is carried out. At last, a case analysis is carried out based on the current situation of waste electrical and electronic equipment (WEEE) recycling in China. The results show that the cross-competitive take-back mode is more advantageous to all participants in the reverse logistics system than the monopolistic take-back mode. Recyclers should actively sign contracts with multiple manufacturers to recycle waste products, making full use of the advantages of cross-competitive take-back mode to maximize the profits of all participants, so as to encourage them to recycle waste products and achieve sustainable development
Influence of minor boron on the microstructures of a second generation Ni-based single crystal superalloy
Boron is added into single crystal superalloys as a micro-alloying element to strengthen low angle grain boundaries. However, systematic investigations on the effect of boron on microstructures of single crystal superalloys are limitedly reported. The effect of boron on as-cast and heat-treated microstructures was investigated in two experimental Ni-based single crystal superalloys containing 3 wt% Re. The current results indicated that the volume fraction of (γ + γ′) eutectic and M3B2 borides was evidently increased, while the number of micropores was evidently decreased with the addition of 0.02 wt% boron. The (γ + γ′) eutectic could not be dissolved completely due to the lower incipient melting temperature caused by the formation of M3B2 borides. Meanwhile, the M3B2 borides were found to be enriched with indispensable strengthening elements Cr, Mo, W and Re, and this may lower the strengthening effect and cause stress concentration during high temperature creep. Keywords: Minor boron, Single crystal superalloys, M3B2 borides, Creep propertie
Magnaporthe oryzae Transcription Factor MoBZIP3 Regulates Appressorium Turgor Pressure Formation during Pathogenesis
The devastating fungus Magnaporthe oryzae (M. oryzae) forms a specialized infection structure known as appressorium, which generates enormous turgor, to penetrate the plant cells. However, how M. oryzae regulates the appressorium turgor formation, is not well understood. In this study, we identified MoBZIP3, a bZIP transcription factor that functioned in pathogenesis in M. oryzae. We found that the pathogenicity of the MoBZIP3 knockout strain (Δmobzip3) was significantly reduced, and the defect was restored after re-expression of MoBZIP3, indicating that MoBZIP3 is required for M. oryzae virulence. Further analysis showed that MoBZIP3 functions in utilization of glycogen and lipid droplets for generation of glycerol in appressorium. MoBZIP3 localized in the nucleus and could bind directly to the promoters of the glycerol synthesis-related genes, MoPTH2, MoTGL1 and MoPEX6, and regulate their expression which is critical for glycerol synthesis in the appressorium turgor pressure generation. Furthermore, the critical turgor sensor gene MoSln1 was also down regulated and its subcellular localization was aberrant in Δmobzip3, which leads to a disordered actin assembly in the Δmobzip3 appressorium. Taken together, these results revealed new regulatory functions of the bZIP transcription factor MoBZIP3, in regulating M. oryzae appressorium turgor formation and infection
Lead Based Halide Crystals for the HHCAL Detector Concept
Good UV transmittance and some scintillation light are two requirements for materials to be used to construct a homogeneous hadron calorimeter (HHCAL) capable to measure both Cherenkov and Scintillation light. In this paper we report an investigation on lead based halide crystals for the HHCAL detector concept, including lead fluoride chloride (PbFCI) and gadolinium doped lead fluoride (PbF_2:Gd) crystals grown at Shanghai Institute of Ceramics. The optical and scintillation properties of PbFCI and PbF_2:Gd crystal samples, such as transmittance and photo-/x- luminescence spectra, light output and corresponding decay time, were measured at room temperature. Excellent UV cutoff edge and short decay time were found in PbFCI crystals. Further development work to improve PbFCI quality for the HHCAL project is discussed
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