1,733 research outputs found

    Studies of pathogenesis-related proteins in the strawberry plant: partial purification of a chitinase-containing protein complex and analysis of an osmotin-like protein gene

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    Plant chitinases and osmotin-like proteins (OLPs) are both pathogenesis-related (PR) proteins, which are implicated in plant responses to pathogen attacks and environmental stresses. In this dissertation, a chitinase-containing protein complex was purified to near homogeneity from strawberry leaf extracts. This protein complex contained at least five different chitinase molecules as revealed by activity gel assays. A previous study showed that winter rye leaves contain seven protein complexes, which consist of various combinations of a chitinase, two glucanase-like proteins (GLPs) and a thaumatin-like protein (TLP). Western blot analysis of the strawberry chitinase complex, however, did not detect the presence of any GLP or TLP in the complex. The second part of this dissertation research dealt with studies of strawberry OLP genes. A genomic clone containing an OLP gene, designated FaOLP2, was isolated and completely sequenced. FaOLP2 contains no intron, and has a potential to encode a precursor protein of 229 amino acid residues with a 27-amino acid signal peptide at the N-terminus. Southern blot analysis showed that FaOLP2 represents a small multi-gene family. The expression of FaOLP2 in different strawberry organs was analyzed using real-time PCR. The result showed that FaOLP2 expressed at different levels in leaves, crowns, roots, green fruits and ripe red fruits. Furthermore, the expression of FaOLP2 under different abiotic stresses was analyzed at different time points. All of the three tested abiotic stimuli, abscisic acid, salicylic acid and mechanical wounding, triggered significant induction of FaOLP2 within 2-6 h post-treatment. Comparing the three stimuli, FaOLP2 was more prominently induced by salicylic acid than by abscisic acid or mechanical wounding. The positive responses of FaOLP2 to these stress factors suggested that FaOLP2 may be involved in the protection of strawberry against pathogen attacks and against osmotic-related stresses. In addition to FaOLP2, the expression of a previously cloned OLP gene (FaOLP1) upon fungal infection was examined at different time points post-infection. Each of the two tested fungal species, Colletotrichum fragariae and Colletotrichum acutatum, triggered a substantial induction of FaOLP1 at 24-48 h post-inoculation, indicating that FaOLP1 could be involved in strawberry defense against fungal infection

    Distributed Relay Selection for Heterogeneous UAV Communication Networks Using A Many-to-Many Matching Game Without Substitutability

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    This paper proposes a distributed multiple relay selection scheme to maximize the satisfaction experiences of unmanned aerial vehicles (UAV) communication networks. The multi-radio and multi-channel (MRMC) UAV communication system is considered in this paper. One source UAV can select one or more relay radios, and each relay radio can be shared by multiple source UAVs equally. Without the center controller, source UAVs with heterogeneous requirements compete for channels dominated by relay radios. In order to optimize the global satisfaction performance, we model the UAV communication network as a many-to-many matching market without substitutability. We design a potential matching approach to address the optimization problem, in which the optimizing of local matching process will lead to the improvement of global matching results. Simulation results show that the proposed distributed matching approach yields good matching performance of satisfaction, which is close to the global optimum result. Moreover, the many-to-many potential matching approach outperforms existing schemes sufficiently in terms of global satisfaction within a reasonable convergence time.Comment: 6 pages, 4 figures, conferenc

    (2,2′-Bipyridine-κ2 N,N′){N-[(2-oxidonaphthalen-1-yl-κO)methyl­idene]-l-valinato-κO}copper(II) trihydrate

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    In the title complex, [Cu(C16H15NO3)(C10H8N2)]·3H2O, the CuII atom is five coordinated by O,N,O′-donor atoms of the Schiff base ligand and by two N atoms of the 2,2′-bipyridine ligand in a distorted square-pyramidal geometry. In the crystal, mol­ecules are linked into a two-dimensional network parallel to (011) by O—H⋯O hydrogen bonds

    On sign-changing solutions for nonlinear operator equations

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    AbstractIn this paper, the existence of sign-changing solutions for nonlinear operator equations is discussed by using the topological degree and fixed point index theory. The main theorems are some new three-solution theorems which are different from the famous Amann's and Leggett-Williams' three-solution theorems as well as the results in [F. Li, G. Han, Generalization for Amann's and Leggett–Williams' three-solution theorems and applications, J. Math. Anal. Appl. 298 (2004) 638–654]. These three solutions are all nonzero. One of them is positive, another is negative, and the third one is a sign-changing solution. Furthermore, the theoretical results are successfully applied to both integral and differential equations

    Margin-Based Few-Shot Class-Incremental Learning with Class-Level Overfitting Mitigation

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    Few-shot class-incremental learning (FSCIL) is designed to incrementally recognize novel classes with only few training samples after the (pre-)training on base classes with sufficient samples, which focuses on both base-class performance and novel-class generalization. A well known modification to the base-class training is to apply a margin to the base-class classification. However, a dilemma exists that we can hardly achieve both good base-class performance and novel-class generalization simultaneously by applying the margin during the base-class training, which is still under explored. In this paper, we study the cause of such dilemma for FSCIL. We first interpret this dilemma as a class-level overfitting (CO) problem from the aspect of pattern learning, and then find its cause lies in the easily-satisfied constraint of learning margin-based patterns. Based on the analysis, we propose a novel margin-based FSCIL method to mitigate the CO problem by providing the pattern learning process with extra constraint from the margin-based patterns themselves. Extensive experiments on CIFAR100, Caltech-USCD Birds-200-2011 (CUB200), and miniImageNet demonstrate that the proposed method effectively mitigates the CO problem and achieves state-of-the-art performance

    Fatigue evaluation of metallic components based on chaotic characteristics of second harmonic generation signal

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    In the nonlinear ultrasonic technique, the nonlinear received signal, such as second harmonic generation (SHG) signal in higher harmonic experiments, is complicated and non-stationary time series which reflects the fatigue damage of metal components. To effectively evaluate the fatigue damage of metal components, especially the earlier fatigue damage, the chaos and fractal theory are proposed to analyze the received signal of higher harmonic experiments. Chaotic characteristics, for example Lyapunov exponent, correlation dimension and Kolmogorov entropy, are extracted to evaluate the fatigue damage. Experiments results indicate that chaotic characteristics can reasonably characterize and evaluate the fatigue state of beams, which the variation trend of chaotic characteristics has a close relationship with fatigue crack propagation. Furthermore, chaotic characteristics are very sensitive to earlier fatigue damage of used connecting rods, especially the Lyapunov exponent. Therefore, chaos and fractal theory could effectively extract the nonlinear received signals, and chaotic characteristics could reasonably evaluate the fatigue damage state of metal components
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