32 research outputs found

    Mutation of Arabidopsis copper-containing amine oxidase gene AtCuAOδ alters polyamines, reduces gibberellin content and affects development

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    Polyamines (PAs) are essential metabolites in plants performing multiple functions during growth and development. Copper-containing amine oxidases (CuAOs) catalyse the catabolism of PAs and in Arabidopsis thaliana are encoded by a gene family. Two mutants of one gene family member, AtCuAOδ, showed delayed seed germination, leaf emergence, and flowering time. The height of the primary inflorescence shoot was reduced, and developmental leaf senescence was delayed. Siliques were significantly longer in mutant lines and contained more seeds. The phenotype of AtCuAOδ over-expressors was less affected. Before flowering, there was a significant increase in putrescine in AtCuAOδ mutant leaves compared to wild type (WT), while after flowering both spermidine and spermine concentrations were significantly higher than in WT leaves. The expression of GA (gibberellic acid) biosynthetic genes was repressed and the content of GA1, GA7, GA8, GA9, and GA20 was reduced in the mutants. The inhibitor of copper-containing amine oxidases, aminoguanidine hydrochloride, mimicked the effect of AtCuAOδ mutation on WT seed germination. Delayed germination, reduced shoot height, and delayed flowering in the mutants were rescued by GA3 treatment. These data strongly suggest AtCuAOδ is an important gene regulating PA homeostasis, and that a perturbation of PAs affects plant development through a reduction in GA biosynthesis

    A proposal to determine the distribution of lateral forces from loaded recycled plastic drainage kerbs

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    Abstract: This study presents a detailed analysis of the lateral forces generated as a result of vertically applied loads to recycled plastic drainage kerbs. These kerbs are a relatively new addition to road infrastructure projects. When concrete is used to form road drainage kerbs, its deformation is minimum when stressed under heavy axle loads. Although recycled plastic kerbs are more environmentally friendly as a construction product, they are less stiff than concrete and tend to deform more under loading leading to a bursting type, lateral force being applied to the haunch materials, the magnitude of which is unknown. A method is proposed for establishing the distribution of these lateral forces resulting from deformation under laboratory test conditions. A load of 400 kN is applied onto a total of six typical kerbs in the laboratory in accordance with the test standard. The drainage kerbs are surrounded with 150 mm of concrete to the front and rear haunch and underneath as is normal during installation. The lateral forces exerted on the concrete surround as a result of deformation of the plastic kerbs are determined via a strain measuring device. Analysis of the test data allows the magnitude of the lateral forces to the surrounding media to be determined and, thereby, ensuring the haunch materials are not over-stressed as a result. The proposed test methodology and subsequent analysis allows for an important laboratory-based assessment of any typical recycled plastic drainage kerbs to be conducted to ensure they are fit-for-purpose in the field

    Systematic analysis and review of video object retrieval techniques

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    Video object retrieval is a promising research direction, developing in the recent years, and the current video object retrieval strategies are used for visualizing, digitizing, modeling, and retrieving the objects especially in graphics and in architectural design. The research performed led to the design of proficient video object retrieval techniques. Yet, although, a number of algorithms had been devised for tracking objects, the problems persist in enhancing the performance, for instance – with regard to non-rigid objects. In this review article we provide a detailed survey of 50 research papers presenting the suggested video object retrieval methodologies, based on approaches such as deep learning techniques, graph-based techniques, query-based techniques, feature-based techniques, fuzzybased techniques, machine learning-based techniques, distance metric learning-based technique, and also other ones. Moreover, analysis and discussion are presented concerning the year of publication, employed methodology, evaluation metrics, accuracy range, adopted framework, datasets utilized, and the implementation tool. Finally, the research gaps and issues related to various proposed video object retrieval schemes are presented for guiding the researchers towards improved contributions to the video object retrieval methods

    Mutation of arabidopsis copper-containing amine oxidase gene AtCuAOδ alters polyamines, reduces gibberellin content and affects development

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    Polyamines (PAs) are essential metabolites in plants performing multiple functions during growth and development. Copper-containing amine oxidases (CuAOs) catalyse the catabolism of PAs and in Arabidopsis thaliana are encoded by a gene family. Two mutants of one gene family member, AtCuAOδ, showed delayed seed germination, leaf emergence, and flowering time. The height of the primary inflorescence shoot was reduced, and developmental leaf senescence was delayed. Siliques were significantly longer in mutant lines and contained more seeds. The phenotype of AtCuAOδ over-expressors was less affected. Before flowering, there was a significant increase in putrescine in AtCuAOδ mutant leaves compared to wild type (WT), while after flowering both spermidine and spermine concentrations were significantly higher than in WT leaves. The expression of GA (gibberellic acid) biosynthetic genes was repressed and the content of GA1, GA7, GA8, GA9, and GA20 was reduced in the mutants. The inhibitor of copper-containing amine oxidases, aminoguanidine hydrochloride, mimicked the effect of AtCuAOδ mutation on WT seed germination. Delayed germination, reduced shoot height, and delayed flowering in the mutants were rescued by GA3 treatment. These data strongly suggest AtCuAOδ is an important gene regulating PA homeostasis, and that a perturbation of PAs affects plant development through a reduction in GA biosynthesis

    Vapor–Liquid Equilibrium Data for Binary Mixtures of Dimethyl Carbonate with Methyl Acetate, Ethyl Acetate, <i>n</i>‑Propyl Acetate, Isopropyl Acetate, <i>n</i>‑Butyl Acetate, and Isoamyl Acetate at 93.13 kPa

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    Isobaric vapor–liquid equilibrium (VLE) data was measured at the local atmospheric pressure of 93.13 kPa for the binary systems of dimethyl carbonate (DMC) with methyl acetate, ethyl acetate, <i>n</i>-propyl acetate, isopropyl acetate, <i>n</i>-butyl acetate, and isoamyl acetate using a dynamic recirculation still. VLE data was generated in the form of <i>T</i>–<i>x</i>,<i>y</i> and was checked for thermodynamic consistency using the Herington area test, Van Ness test, and mean absolute deviation between experimental and calculated total pressure and vapor phase composition. Data for all pairs meet the criteria for thermodynamic consistency and were found suitable for process modeling. Binary interaction parameters for the Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) activity coefficient models were determined using the objective function of minimizing the deviation between the experimental and the calculated vapor phase composition and total pressure. For all binary systems, Wilson, NRTL, and UNIQUAC models gave good predictions. Azeotropic behavior was observed for the isopropyl acetate–DMC pair at 357.8 K and 0.6 mole fraction of isopropyl acetate
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