26 research outputs found

    A Computational Model for Children's Language Acquisition using Inductive Logic Programming

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    This paper proposes a computational model for children's word acquisition based on inductive logic programming. There are three fundamental features in our approach. Firstly, we incorporate cognitive biases developed recently to explain the efficiency of children's language acquisition. Secondly, we design a co-evolution mechanism of acquiring concept definitions for words and developing concept hierarchy. Concept hierarchy plays an important role of defining contexts for later word learning processes. A context switching mechanism is used to select a relevant set of attributes for learning a word depending on the category which it belongs to. On the other hand, during acquiring definitions for words, concept hierarchy is developed. Thirdly, we pursue resemblance to human brain in functional level.We developed an experimental language acquisition system called WISDOM (Word Induction System for Deriving Object Model) and conducted virtual experiments or simulations on acquisition of words in two different categories. The experiments shows feasibility of our approach

    Identification of a novel mechanism of action of bovine IgG antibodies specific for Staphylococcus aureus

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    Staphylococcus aureus is a major pathogen that causes subclinical mastitis associated with huge economic losses to the dairy industry. A few vaccines for bovine mastitis are available, and they are expected to induce the production of S. aureus-specific antibodies that prevent bacterial adherence to host cells or promote opsonization by phagocytes. However, the efficacy of such vaccines are still under debate; therefore, further research focusing on improving the current vaccines by seeking additional mechanisms of action is required to reduce economic losses due to mastitis in the dairy industry. Here, we generated S. aureus-specific bovine IgG antibodies (anti-S. aureus) that directly inhibited bacterial growth in vitro. Inhibition depended on specificity for anti-S. aureus, not the interaction between Protein A and the fragment crystallizable region of the IgG antibodies or bacterial agglutination. An in vitro culture study using S. aureus strain JE2 and its deletion mutant JE2ΔSrtA, which lacks the gene encoding sortase A, revealed that the effect of anti-S. aureus was sortase-A-independent. Sortase A is involved in the synthesis of cell-wall-associated proteins. Thus, other surface molecules, such as membrane proteins, cell surface polysaccharides, or both, may trigger the inhibition of bacterial growth by anti-S. aureus. Together, our findings contribute insights into developing new strategies to further improve the available mastitis vaccine by designing a novel antigen on the surface of S. aureus to induce inhibitory signals that prevent bacterial growth

    Identification of a novel mechanism of action of bovine IgG antibodies specific for Staphylococcus aureus

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    International audienceAbstractStaphylococcus aureus is a major pathogen that causes subclinical mastitis associated with huge economic losses to the dairy industry. A few vaccines for bovine mastitis are available, and they are expected to induce the production of S. aureus-specific antibodies that prevent bacterial adherence to host cells or promote opsonization by phagocytes. However, the efficacy of such vaccines are still under debate; therefore, further research focusing on improving the current vaccines by seeking additional mechanisms of action is required to reduce economic losses due to mastitis in the dairy industry. Here, we generated S. aureus-specific bovine IgG antibodies (anti-S. aureus) that directly inhibited bacterial growth in vitro. Inhibition depended on specificity for anti-S. aureus, not the interaction between Protein A and the fragment crystallizable region of the IgG antibodies or bacterial agglutination. An in vitro culture study using S. aureus strain JE2 and its deletion mutant JE2ΔSrtA, which lacks the gene encoding sortase A, revealed that the effect of anti-S. aureus was sortase-A-independent. Sortase A is involved in the synthesis of cell-wall-associated proteins. Thus, other surface molecules, such as membrane proteins, cell surface polysaccharides, or both, may trigger the inhibition of bacterial growth by anti-S. aureus. Together, our findings contribute insights into developing new strategies to further improve the available mastitis vaccine by designing a novel antigen on the surface of S. aureus to induce inhibitory signals that prevent bacterial growth

    New Accelerator Facility for Carbon-Ion Caner-Therapy

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    The first clinical trial with carbon beams generated from the HIMAC was conducted in June 1994. The total number of patients treated as of December 2006 was in excess of 3,000. In view of the significant growth in the number of protocols, the Japanese government gave its approval for carbon-ion therapy at NIRS as an advanced medical technology in 2003. The impressive advances of carbon-ion therapy using HIMAC have been supported by high-reliability operation and by advanced developments of beam-delivery and accelerator technologies. Based on our ten years of experience with HIMAC, we recently proposed a new accelerator facility for cancer therapy with carbon ions for widespread use in Japan. The key technologies of the accelerator and beam-delivery systems for this proposed facility have been under development since April 2004, with the main thrust being focused on downsizing the facility for cost reduction. Based on the design and R&D studies for the proposed facility, its construction was begun at Gunma University in April 2006. In addition, our future plans for HIMAC also include the design of a new treatment facility. The design work has already been initiated, and will lead to the further development of therapy using HIMAC. The following descriptions give a summary account of the new accelerator facility for cancer therapy with carbon ions and of the new treatment facility at HIMAC

    Analysis of Macular Drusen and Blood Test Results in 945 <i>Macaca fascicularis</i>

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    <div><p>Age-dependent formation of macular drusen caused by the focal accumulation of extracellular deposits beneath the retinal pigment epithelium precede the development of age-related macular degeneration (AMD), one of the leading causes of blindness worldwide. It is established that inflammation contributes to the pathogenesis of drusen and AMD. However, development of a preemptive therapeutic strategy targeting macular drusen and AMD has been impeded by the lack of relevant animal models because most laboratory animals lack macula, an anatomic feature present only in humans and a subset of monkeys. Reportedly, macular drusen and macular degeneration develop in monkeys in an age-dependent manner. In this study, we analyzed blood test results from 945 <i>Macaca fascicularis</i>, 317 with and 628 without drusen. First, a trend test for drusen frequency (the Cochran–Armitage test) was applied to the quartile data for each parameter. We selected variables with an increasing or decreasing trend with higher quartiles at P < 0.05, to which multivariate logistic regression analysis was applied. This revealed a positive association of age (odds ratio [OR]: 1.10 per year, 95% confidence interval [CI]: 1.07–1.12) and white blood cell count (OR: 1.01 per 1 × 10<sup>3</sup>/μl, 95% CI: 1.00–1.01) with drusen. When the monkeys were divided by age, the association between drusen and white blood cell count was only evident in younger monkeys (OR: 1.01 per 1 × 10<sup>3</sup>/μl, 95% CI: 1.00–1.02). In conclusion, age and white blood cell count may be associated with drusen development in <i>M</i>. <i>fascicularis</i>. Systemic inflammation may contribute to drusen formation in monkeys.</p></div
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