475 research outputs found

    On-Line Cursive Korean Character Recognition by using Curvature Models

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    A cursive Korean character consists of several Korean alphabets where connection is present within and among the alphabets. Recognition of Korean characters can be carried out by splitting each character into smaller primitives. Small line segments can be used as the primitives. But this approach requires too much processing time, for there can be many candidate references to be matched to one input character and each reference usually consists of too many primitives. In this paper, we propose an approach using structural curvature models to overcome the difficulties of using small line segments. These models are obtained by segmenting the input character at the points showing sudden change in direction, excessive rotation, etc. By doing this, rather larger and structural curve segments can be used as the basic primitives to be matched resulting in the savings of processing time and better recognition rat

    Indole and 3-indolylacetonitrile inhibit spore maturation in Paenibacillus alvei

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    <p>Abstract</p> <p>Background</p> <p>Bacteria use diverse signaling molecules to ensure the survival of the species in environmental niches. A variety of both Gram-positive and Gram-negative bacteria produce large quantities of indole that functions as an intercellular signal controlling diverse aspects of bacterial physiology.</p> <p>Results</p> <p>In this study, we sought a novel role of indole in a Gram-positive bacteria <it>Paenibacillus alvei </it>that can produce extracellular indole at a concentration of up to 300 μM in the stationary phase in Luria-Bertani medium. Unlike previous studies, our data show that the production of indole in <it>P. alvei </it>is strictly controlled by catabolite repression since the addition of glucose and glycerol completely turns off the indole production. The addition of exogenous indole markedly inhibits the heat resistance of <it>P. alvei </it>without affecting cell growth. Observation of cell morphology with electron microscopy shows that indole inhibits the development of spore coats and cortex in <it>P. alvei</it>. As a result of the immature spore formation of <it>P. alvei</it>, indole also decreases <it>P. alvei </it>survival when exposed to antibiotics, low pH, and ethanol. Additionally, indole derivatives also influence the heat resistance; for example, a plant auxin, 3-indolylacetonitrile dramatically (2900-fold) decreased the heat resistance of <it>P. alvei</it>, while another auxin 3-indoleacetic acid had a less significant influence on the heat resistance of <it>P. alvei</it>.</p> <p>Conclusions</p> <p>Together, our results demonstrate that indole and plant auxin 3-indolylacetonitrile inhibit spore maturation of <it>P. alvei </it>and that 3-indolylacetonitrile presents an opportunity for the control of heat and antimicrobial resistant spores of Gram-positive bacteria.</p

    Isolation and characterization of NgRLK1, a receptor-like kinase of Nicotiana glutinosa that interacts with the elicitin of Phytophthora capsici

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    Elicitins, extracellular proteins from Phytophthora fungi, elicit a hypersensitivity response (HR), including systemic acquired resistance, in some plants. The elicitin capsicein (~10 kDa) was purified by FPLC from culture filtrates of P. capsici. Purified native and recombinant capsicein induced a hypersensitive response in leaves of the non-host plants Nicotiana glutinosa and Brassica rapa subsp. pekinensis. To search for candidate capsicein-interacting proteins from N. glutinosa, a yeast two-hybrid assay was used. We identified a protein interactor that is homologous to a serine/threonine kinase of the plant receptor-like kinase (RLK) group and designated it NgRLK1. The ORF of NgRLK1 encodes a polypeptide of 832 amino acids (93,490 Da). A conserved domain analysis revealed that NgRLK1 has structural features typical of a plant RLK. NgRLK1 was autophosphorylated, with higher activity in the presence of Mn2+ than Mg2+

    Synchrotron x-ray imaging visualization study of capillary-induced flow and critical heat flux on surfaces with engineered micropillars

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    Over the last several decades, phenomena related to critical heat flux (CHF) on structured surfaces have received a large amount of attention from the research community. The purpose of such research has been to enhance the safety and efficiency of a variety of thermal systems. A number of theories have been put forward to explain the key CHF enhancement mechanisms on structured surfaces. However, these theories have not been confirmed experimentally because of limitations in the available visualization techniques and the complexity of the phenomena. To overcome these limitations and elucidate the CHF enhancement mechanism on the structured surfaces, we introduce synchrotron x-ray imaging with high spatial (similar to 2 mu m) and temporal (similar to 20,000 Hz) resolutions. This technique has enabled us to confirm that capillary-induced flow is the key CHF enhancement mechanism on structured surfaces.11Ysciescopu
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