106 research outputs found

    Ultracompact bottom-up photonic crystal lasers on silicon-on-insulator

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    Abstract Compact on-chip light sources lie at the heart of practical nanophotonic devices since chip-scale photonic circuits have been regarded as the next generation computing tools. In this work, we demonstrate room-temperature lasing in 7 × 7 InGaAs/InGaP core-shell nanopillar array photonic crystals with an ultracompact footprint of 2300 × 2300 nm2, which are monolithically grown on silicon-on-insulator substrates. A strong lateral confinement is achieved by a photonic band-edge mode, which is leading to a strong light-matter interaction in the 7 × 7 nanopillar array, and by choosing an appropriate thickness of a silicon-on-insulator layer the band-edge mode can be trapped vertically in the nanopillars. The nanopillar array band-edge lasers exhibit single-mode operation, where the mode frequency is sensitive to the diameter of the nanopillars. Our demonstration represents an important first step towards developing practical and monolithic III-V photonic components on a silicon platform

    Autonomous task execution of a humanoid robot using a cognitive model

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    Abstract—These days, there are many studies on cognitive architectures, which are developed based on human cognitive models. Some other studies are focused on applying these cognitive architectures to the autonomous task execution of humanoid robots. In this paper, we have shown that a real world robot, Mahru-Z can execute a task autonomously in the Blocks World domain, using a cognitive architecture, ICARUS. For this project, diverse techniques such as system integration, human-like manipulation based on vision, environmental information update techniques etc are used. Successful completions of these tasks imply that we can expect similar results for the more diverse and complicated tasks as well. I

    Identification of DNA methylation changes associated with human gastric cancer

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    <p>Abstract</p> <p>Background</p> <p>Epigenetic alteration of gene expression is a common event in human cancer. DNA methylation is a well-known epigenetic process, but verifying the exact nature of epigenetic changes associated with cancer remains difficult.</p> <p>Methods</p> <p>We profiled the methylome of human gastric cancer tissue at 50-bp resolution using a methylated DNA enrichment technique (methylated CpG island recovery assay) in combination with a genome analyzer and a new normalization algorithm.</p> <p>Results</p> <p>We were able to gain a comprehensive view of promoters with various CpG densities, including CpG Islands (CGIs), transcript bodies, and various repeat classes. We found that gastric cancer was associated with hypermethylation of 5' CGIs and the 5'-end of coding exons as well as hypomethylation of repeat elements, such as short interspersed nuclear elements and the composite element SVA. Hypermethylation of 5' CGIs was significantly correlated with downregulation of associated genes, such as those in the <it>HOX </it>and histone gene families. We also discovered long-range epigenetic silencing (LRES) regions in gastric cancer tissue and identified several hypermethylated genes (<it>MDM2</it>, <it>DYRK2</it>, and <it>LYZ</it>) within these regions. The methylation status of CGIs and gene annotation elements in metastatic lymph nodes was intermediate between normal and cancerous tissue, indicating that methylation of specific genes is gradually increased in cancerous tissue.</p> <p>Conclusions</p> <p>Our findings will provide valuable data for future analysis of CpG methylation patterns, useful markers for the diagnosis of stomach cancer, as well as a new analysis method for clinical epigenomics investigations.</p

    A Case of Anaphylaxis to Chlorhexidine during Digital Rectal Examination

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    Chlorhexidine is widely used as an antiseptic and disinfectant in medical and non-medical environments. Although the sensitization rate seems to be low, its ubiquitous use raises the possibility of sensitization in many patients and medical care workers. We describe a patient with anaphylaxis during digital rectal examination with chlorhexidine jelly. Urticaria, angioedema, dyspnea, and hypotension developed within a few minutes of the rectal examination. The patient fully recovered after treatment with epinephrine and corticosteroids. Skin tests for chlorhexidine were undertaken 5 weeks later, showing positive prick and intradermal skin tests. Within 30 min of the skin test, the patient complained of febrile sensation, chest tightness, angioedema, and urticaria on the face and trunk. An enzyme allergosorbent test for latex was negative. We present this case to alert clinicians about hypersensitivity to chlorhexidine that could potentially be life-threatening. We suggest that chlorhexidine should be recognized as a causative agent of anaphylaxis during procedural interventions

    Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

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    A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

    Entrainment-enhanced Neural Oscillator for Imitation Learning

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    To achieve biologically inspired robot control architectures based on neural oscillator networks, goal-directed imitation is addressed with respect to the problem of motion generation. It would be desirable to easily acquire appropriate motion patterns for skill learning between dissimilar bodies to attain the goal of the demonstrated motion. This requires neural oscillator networks to adapt to the non-periodic nature of arbitrary input patterns exploiting their entrainment properties. However, even in the most widely-used Matsuoka oscillator, when an unknown quasi-periodic or non-periodic signal is applied, its output signal is not always closely entrained. Therefore, current neural oscillator models may not be applied to the proposed goal-directed imitation for skill learning. To solve this problem, a supplementary term is newly included in the equation of Matsuoka oscillator. We verify general properties of the proposed model of the neural oscillator and illustrate in particular its enhanced entrainment by numerical simulation. We also show the possibility of controlling dynamic responses of oscillator-coupled mechanical systems. Technical implications of the results are discussed
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