The range of sap-sucking insect pests to which GNA, (the mannose specific lectin from snowdrops (Galanthus nivalis)) has been shown to be insecticidal in artificial diets has been extended to include the peach potato aphid (Myzuspersicae). A gene construct for constitutive expression of GNA from the CaMV35S gene promoter has been introduced into tobacco plants. A transgenic tobacco line which expresses high levels of GNA has been shown to have enhanced resistance to M. persicae in leaf disc and whole plant bioassays, demonstrating the potential for extending transgenic plant technology to the control of sap-sucking insect pests.
Nuclear genome analysis using RFLPs and RAPDs has been assessed within different species of the genus Brachypodium P. Beauv. and representatives of other grasses in order to determine the characteristics of the Brachypodium genome and to establish its evolutionary position in relation to other Pooideae. Distinctive features of the Brachypodium genome are its small size, the low amount of repetitive DNA, the lack of restriction fragment length polymorphisms within the genus for the assayed probe/enzyme combinations, and the genomic variability demonstrated at species level by random DNA amplification. These molecular studies confirm Brachypodium as an isolated ancient genus best placed in its own tribe (Brachypodieae). Its relationships to other tribes Bromeae, Triticeae, Poeae are resolved, Brachypodieae being the earliest tribe to diverge from this core of pooids. Within the genus two major Old World clades are distinguishable: an annual clade, represented only by B. distachyon; and a perennial clade, represented by all the other species studied (except B. mexicanum). The perennial American species B. mexicanum appears equally attached to these two clades. RFLP data were found to be useful in obtaining phylogenies at generic and higher rank levels, whereas the highly variable RAPD data were more suitable for resolving interspecific and intraspecific evolutionary pathways.
With recent advancements in additive manufacturing (AM) technology, it is possible to deposit copper conductive paths and insulation layers of an electric machine in a selective controlled manner. AM of copper enables higher fill factors that improves the internal thermal conduction in the stator core of the electric machine (induction motor), which will enhance its efficiency and power density. This will reduce the motor size and weight and make it more suitable for aerospace and electric vehicle applications, while reducing/eliminating the rare-earth dependency. The objective of this paper is to present the challenges associated with AM of copper coils having 1 × 1 mm cross section and complex features that are used in producing ultra-high efficiency induction motor for traction applications. The paper also proposes different approaches that were used by the authors in attempts to overcome those challenges. The results of the developed technologies illustrate the important of copper powder treatment to help in flowing the powder easier during deposition. In addition, the treated powder has higher resistance to surface oxidation, which led to a high reduction in porosity formation and improved the quality of the copper deposits. The laser powder direct energy deposition (LPDED) process modeling approach helps in optimizing the powder deposition path, the laser power, and feed rate that allow the production of porosity free thin wall and thin floor components. The laser powder bed fusion (LPBF) models identify the optimum process parameters that are used to produce test specimens with >90% density and minimum porosity.
Nanocrystalline cellulose (NCC) was used for improving the formaldehyde (HCHO) emission and bonding strength of urea formaldehyde (UF) resin adhesive in fiberboard and plywood. The original NCC was modified by 3-aminopropyltriethoxysilane (APTES) and the wetting property with UF resin adhesive was improved by 26.4%. The UF resin adhesive with modified NCC was characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TG) and Fourier transform infrared (FT-IR). The crystal region of UF resin adhesive was influenced by NCC and the diffraction intensity of the peak at 2θ = 22.82° was enhanced significantly. The thermal stability of UF resin adhesive with 1.0% modified NCC increased by 4.9%. And modified NCC led hydroxyl groups into the UF resin adhesive. HCHO emission and bonding strength of the UF resin adhesive with modified NCC were tested according to Chinese National Standards GB/T 17657-1999 and GB/T 9846-2004. The HCHO emission of fiberboard and plywood with 1.5% modified NCC decreased by 13.0% and 53.2%, respectively. The bonding strength of fiberboard increased by 158.3% (from 0.12 MPa of control group to 0.31 MPa of fiberboard with 1.5% modified NCC), while 1.5% modified NCC led to a 23.6% increase in the plywood.
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