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During threshing rice straw is broken, it becomes mixed with the grains, but it is separated from the grains in the subsequent cleaning process. Reducing broken rice straw can thus help improve cleaning performance. The effect of concentric and non-concentric threshing gaps on threshing performance is different. In this paper, rigid short and flexible long rice straw models were established using discrete element method (DEM) and the flexible model was verified by a three-point bending test. Threshing simulations using the developed straw models and a bench test were conducted to analyse the effects of concentric and non-concentric threshing gaps on rice straw damage. The simulation results showed that comparing concentric with non-concentric gaps the average compressive force on rice straw fluctuated less and the bonds of flexible long rice straw had a lower break proportion. Bench test results showed that the mass fraction of material other than grain (MOG) in threshing outputs with the concentric threshing gap was 4.3% lower than with the non-concentric gap, and the damage level of rice straw was also lower. • Rigid short and flexible long straw models using DEM were established. • The average compressive force on straw was analyzed by threshing simulation. • The weight percentage of MOG in threshing outputs under concentric gap was lower. • The damage level of straw under concentric gap was lower than non-concentric one. [ABSTRACT FROM AUTHOR]

Abstract: A novel epoxide hydrolase from Aspergillus niger SQ-6 has now been cloned by inverse PCR. Its gene shows eight exons including a non-coding exon at its 5′-terminal (GenBank Accession No. AY966486). Phylogenetic analysis using deduced amino acid sequence (395 aa) confirms it as an epoxide hydrolase and shares 58.3% identity with that of A. niger LCP521 (GenBank Accession No. AF238460). The predicted catalytic triad is composed of Asp191, His369 and Glu343. Active recombinant epoxide hydrolase has been successfully expressed in Escherichia coli as protein fusions with a poly-His tail. Scale-up fermentation can yield 2.5g/L of recombinant protein. The electrophoretic pure recombinant protein, which shows similar characterization as natural enzyme purified from A. niger SQ-6, can be easily purified by Ni2+-chelated affinity and gel-filtration chromatography. Optimal pH and temperature for purified enzyme are pH 7.5 and 37°C, respectively. The K m, k cat and maximal velocity (V max) for p-nitrostyrene oxide are determined to be 1.02mM, 172s−1 and 231μmol min−1 mg−1, respectively. The enzyme can be inhibited by oxidant (H2O2), solvent (Tetrahydrofuran) and several metal ions including Hg2+, Fe2+ and Co2+. This (R)-stereospecific epoxide hydrolase exhibits high enantioselectivity (enantiomeric excess value, 99%) for the less hindered carbon atom of epoxide. It may be an industrial biocatalyst for the preparation of enantiopure epoxides or vicinal diols. [Copyright &y& Elsevier]

Path planning is a critical aspect of the harvesting process for unmanned combine harvesters, and the headland turning paths play a crucial role in connecting two parallel paths. However, previous studies have often simplified the combine harvester as a mass point, leading to suboptimal or meaningless planned paths. In this paper, a simplified geometrical model for a tracked combine harvester that considers the influence of the header and tracks on headland turning was developed. Using this model, new calculation formulae for path length, turning time, and headland width for four commonly used headland turning types: fishtail turn, bulb turn, semicircle turn, and u turn were deduced and deeply analysed. The results revealed that the semicircle turn achieved the greatest reduction in path length, turning time, and headland width, reaching up to 79.0%, 74.0%, and 36.1%, respectively, if the harvester turned to the left. To ensure sufficient turning area for unmanned harvesting, the field periphery should be cut at least twice for u turns, three times for semicircle turns, three to four times for fishtail turns, and three to five times for bulb turns. It is suggested that the semicircle turn is the preferred option for most situations, and the harvester should switch between the semicircle turn and the u turn in special cases if it has a differential steering function. This approach can significantly improve working efficiency and always determine the minimum required headland width. • A new simplified model for tracked combine harvester is developed. • New formulas of path length, turning time and headland turning width are deduced. • Four common turning types' performances are analysed thoroughly. • Guidance and advice are concluded for better path planning. [ABSTRACT FROM AUTHOR]

Abstract: Ustilago maydis is an important model fungal organism for diverse studies. Little improvement has been made in the method for its transformation since the PEG-mediated transfection of spheroplasts that was reported more than 20years ago. We have constructed binary T-DNA vectors carrying Hygromycin and Nourseothricin resistance gene cassettes and have developed a highly efficient method for transformation of this fungus based on Agrobacterium tumefaciens-mediated transformation (ATMT). Through a series of optimization, at least 1×104 Hygromycin B resistant colony forming units (CFU) have been achieved on each 90mm agar plate using 106 sporidia. Optimal pH value for ATMT is approximately 5.6. Approximately 96% Hygromycin B-resistant transformants contain a single-copy T-DNA inserted into the nuclear genome. Analysis of 204 T-DNA flanking sequences showed that 15.2% of them were found in the coding sequences and a further 37.25% within 0.5kb from the coding sequences at the 5′ UTR or promoter regions. In addition, a method for preparation and preservation of transformation-ready T-DNA donor and receptor cells has been developed allowing gene tagging experiments to be performed on-demand. An initial screening of 5000 mutants resulted in the identification of a putative farnesyl transferase beta subunit and a PRE6 homologue as new players of sexual mating in U. maydis. [Copyright &y& Elsevier]

Abstract: We show how a layered Cloud service model of software (SaaS), platform (PaaS), and infrastructure (IaaS) leverages multiple independent Clouds by creating a federation among the providers. The layered architecture leads naturally to a design in which inter-Cloud federation takes place at each service layer, mediated by a broker specific to the concerns of the parties at that layer. Federation increases consumer value for and facilitates providing IT services as a commodity. This business model for the Cloud is consistent with broker mediated supply and service delivery chains in other commodity sectors such as finance and manufacturing. Concreteness is added to the federated Cloud model by considering how it works in delivering the Weather Research and Forecasting service (WRF) as SaaS using PaaS and IaaS support. WRF is used to illustrate the concepts of delegation and federation, the translation of service requirements between service layers, and inter-Cloud broker functions needed to achieve federation. [Copyright &y& Elsevier]