183 research outputs found

    Impact of Electron Collision Mixing on the delay times of an electron beam excited Atomic Xenon laser

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    The atomic xenon (5dÂż6p) infrared laser has been experimentally and theoretically investigated using a short-pulse (30-ns), high-power (1-10-MW/cm3) coaxial electron beam excitation source. In most cases, laser oscillation is not observed during the e-beam current pulse. Laser pulses of hundreds of nanoseconds duration are subsequently obtained, however, with oscillation beginning 60-800 ns after the current pulse terminates. Results from a computer model for the xenon laser reproduce the experimental values and show that oscillation begins when the fractional electron density decays below a critical value of ≈0.2-0.8×10 6. These results lend credence to the proposal that electron collision mixing of the laser levels limits the maximum value of specific power deposition that can be used to excite the atomic xenon laser efficiently on a quasi-CW basi

    Melhoramento de mandioca para aumento do teor de betacaroteno.

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    O objetivo desse trabalho foi avaliar o teor de carotenoides e compostos cianogĂȘnicos em mandioca para mesa. Foram avaliados 78 clones resultantes da autofecundação de 16 acessos (BGM 61, BGM 66, BGM 878, BGM 893, BGM 913, BGM 952, BGM 971, BGM 991, BGM 1137, BGM 1146, BGM 1186, BGM 1702, BGM 1706, BGM 1708, BGM 1709 e BGM 1776) do Banco de Germoplasama da Embrapa Mandioca e Fruticultura. Os teores de carotenoides variaram de 4,43 a 16,12 ”g.g-1, enquanto os de compostos cianogĂȘnicos variaram de 60,8 a 298,1 ”g.g-1. Entretanto, os teores de compostos cianogĂȘnicos desses clones de maior teor de carotenoides tenderam a ser maiores que 100 ppm, e assim, eles nĂŁo podem ser selecionados como mandioca mansa. Como os clones que tĂȘm teores baixos de HCN e altos teores de carotenoides ainda tĂȘm que atender a outros critĂ©rios relacionados Ă  qualidade, torna-se difĂ­cil identificar um que atenda a todos esses critĂ©rios. Assim, a estratĂ©gia que estĂĄ sendo adotada Ă© o intercruzamento entre os clones que possuem teores elevados de betacaroteno e baixos teores de compostos cianogĂȘnicos, visando continuar obtendo progresso no melhoramento para aumento do teor de betacaroteno, mantendo baixo o teor de compostos cianogĂȘnicos.PDF. T98

    Linguistic Factors Affecting Moraic Duration in Spontaneous Japanese

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    Japanese is often referred to as a mora-timed language (Ladefoged 1975): the mora has been described as the psychological prosodic unit in the spoken language, and it is the metric unit of traditional poetry (Bloch 1950). However, it is clear that mo- rae are not strictly isochronous units (Beckman 1982). Thus, experimental studies have focused on detecting compensation effects that make average mora durations more equal through the modulation of the inherent duration of the segments involved (Han 1962; Port, Al-Ani, Maeda 1980; Homma 1981; Hoequist 1983a; 1983b; Warner, Arai 2001). Kawahara (2017) used the Corpus of Spontaneous Japanese to verify whether the dura- tional compensation effect within a /CV/ mora occurs in natural speech, in addition to read speech in the lab. He observed a statistically significant compensation effect of /CV/ morae, in which vowel duration tends to vary in response to the duration of the preced- ing consonant. However, as the same author has pointed out, the compensation is not absolute because there are several linguistic factors that potentially affect segments’ duration profiles. This study will support the idea that moraic isochrony does not occur in spontaneous Japanese by presenting empirical data on how linguistic factors can considerably affect variation in the average duration of morae

    Erlotinib inhibits osteolytic bone invasion of human non-small-cell lung cancer cell line NCI-H292

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    Previous preclinical and clinical findings have suggested a potential role of epidermal growth factor receptor (EGFR) in osteoclast differentiation and the pathogenesis of bone metastasis in cancer. In this study, we investigated the effect of erlotinib, an orally active EGFR tyrosine kinase inhibitor (TKI), on the bone invasion of human non-small-cell lung cancer (NSCLC) cell line NCI-H292. First, we established a novel osteolytic bone invasion model of NCI-H292 cells which was made by inoculating cancer cells into the tibia of scid mice. In this model, NCI-H292 cells markedly activated osteoclasts in tibia, which resulted in osteolytic bone destruction. Erlotinib treatment suppressed osteoclast activation to the basal level through suppressing receptor activator of NF-ÎșB ligand (RANKL) expression in osteoblast/stromal cell at the bone metastatic sites, which leads to inhibition of osteolytic bone destruction caused by NCI-H292 cells. Erlotinib inhibited the proliferation of NCI-H292 cells in in vitro. Erlotinib suppressed the production of osteolytic factors, such as parathyroid hormone-related protein (PTHrP), IL-8, IL-11 and vascular endothelial growth factor (VEGF) in NCI-H292 cells. Furthermore, erlotinib also inhibited osteoblast/stromal cell proliferation in vitro and the development of osteoclasts induced by RANKL in vitro. In conclusion, erlotinib inhibits tumor-induced osteolytic invasion in bone metastasis by suppressing osteoclast activation through inhibiting tumor growth at the bone metastatic sites, osteolytic factor production in tumor cells, osteoblast/stromal cell proliferation and osteoclast differentiation from mouse bone marrow cells

    Development of a real-time quantitative PCR assay for detection of a stable genomic region of BK virus

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    <p>Abstract</p> <p>Background</p> <p>BK virus infections can have clinically significant consequences in immunocompromised individuals. Detection and monitoring of active BK virus infections in certain situations is recommended and therefore PCR assays for detection of BK virus have been developed. The performance of current BK PCR detection assays is limited by the existence of viral polymorphisms, unknown at the time of assay development, resulting in inconsistent detection of BK virus. The objective of this study was to identify a stable region of the BK viral genome for detection by PCR that would be minimally affected by polymorphisms as more sequence data for BK virus becomes available.</p> <p>Results</p> <p>Employing a combination of techniques, including amino acid and DNA sequence alignment and interspecies analysis, a conserved, stable PCR target region of the BK viral genomic region was identified within the VP2 gene. A real-time quantitative PCR assay was then developed that is specific for BK virus, has an analytical sensitivity of 15 copies/reaction (450 copies/ml) and is highly reproducible (CV ≀ 5.0%).</p> <p>Conclusion</p> <p>Identifying stable PCR target regions when limited DNA sequence data is available may be possible by combining multiple analysis techniques to elucidate potential functional constraints on genomic regions. Applying this approach to the development of a real-time quantitative PCR assay for BK virus resulted in an accurate method with potential clinical applications and advantages over existing BK assays.</p
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