1,169 research outputs found

    Recombinant expression and functional characterisation of regiospecific flavonoid glucosyltransferases from Hieracium pilosella L.

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    Five glucosyltransferases were cloned by RT-PCR amplification using total RNA from Hieracium pilosella L. (Asteraceae) inflorescences as template. Expression was accomplished in Escherichia coli, and three of the HIS-tagged enzymes, UGT90A7, UGT95A1, and UGT72B11 were partially purified and functionally characterised as UDP-glucose:flavonoid O-glucosyltransferases. Both UGT90A7 and UGT95A1 preferred luteolin as substrate, but possessed different regiospecificity profiles. UGT95A1 established a new subgroup within the UGT family showing high regiospecificity towards the C-3' hydroxyl group of luteolin, while UGT90A7 primarily yielded the 4'-O-glucoside, but concomitantly catalysed also the formation of the 7-O-glucoside, which could account for this flavones glucoside in H. pilosella flower heads. Semi quantitative expression profiles revealed that UGT95A1 was expressed at all stages of inflorescence development as well as in leaf and stem tissue, whereas UGT90A7 transcript abundance was nearly limited to flower tissue and started to develop with the pigmentation of closed buds. Other than these enzymes, UGT72B11 showed rather broad substrate acceptance, with highest activity towards flavones and flavonols which have not been reported from H. pilosella. As umbelliferone was also readily accepted, this enzyme could be involved in the glucosylation of coumarins and other metabolite

    Effect of speaker age on speech recognition and perceived listening effort in older adults with hearing loss

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    Published online January 2012Purpose: Older adults exhibit difficulty understanding speech that has been experimentally degraded. Age-related changes to the speech mechanism lead to natural degradations in signal quality. We tested the hypothesis that older adults with hearing loss would exhibit declines in speech recognition when listening to the speech of older adults, compared with the speech of younger adults, and would report greater amounts of listening effort in this task. Methods: Nineteen individuals with age-related hearing loss completed speech recognition and listening effort scaling tasks. Both were conducted in quiet, when listening to high and low predictability phrases produced by younger and older speakers respectively. Results: No significant difference in speech recognition existed when stimuli were derived from younger or older speakers. However, perceived effort was significantly higher when listening to speech from older adults, as compared to younger adults. Conclusions: For older individuals with hearing loss, natural degradations in signal quality may require greater listening effort. However, they do not interfere with speech recognition – at least in quiet. Follow-up investigation of the effect of speaker age on speech recognition and listening effort under more challenging noise conditions appears warranted

    Spin-orbit coupled j=1/2 iridium moments on the geometrically frustrated fcc lattice

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    Motivated by experiments on the double perovskites La2ZnIrO6 and La2MgIrO6, we study the magnetism of spin-orbit coupled j=1/2 iridium moments on the three-dimensional, geometrically frustrated, face-centered cubic lattice. The symmetry-allowed nearest-neighbor interaction includes Heisenberg, Kitaev, and symmetric off-diagonal exchange. A Luttinger-Tisza analysis shows a rich variety of orders, including collinear A-type antiferromagnetism, stripe order with moments along the [111]-direction, and incommensurate non-coplanar spirals, and we use Monte Carlo simulations to determine their magnetic ordering temperatures. We argue that existing thermodynamic data on these iridates underscores the presence of a dominant Kitaev exchange, and also suggest a resolution to the puzzle of why La2ZnIrO6 exhibits `weak' ferromagnetism, but La2MgIrO6 does not.Comment: 5 pages, 5 figs, significantly revised to address referee comments, to appear in PRB Rapid Com

    Исследование парогазовой установки, работающей на генераторном газе

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    Выпускная квалификационная работа 116 страниц, 25 рисунков, 25 таблиц, 35 источников, 2 приложения. Ключевые слова: газификация угля, парогазовая установка, газотурбинная установка, генераторный газ, анализ, котел-утилизатор, показатели эффективности. Объектом исследования является ПГУ, работающая на генераторном газе. Цель работы – анализ работоспособности такой ПГУ с ГТУ, работающей на генераторном газе. В процессе исследования проводилось изучение различных способов газификации угля; производился выбор расчетной схемы ПГУ с газификацией; проводился расчет состава и характеристик генераторного газа и определение основных показателей тепловой эффективности ПГУ. В результате исследования был сделан анализ эффективности работы парогазовой установки.Final qualifying work of 116 pages, 25 figures, 25 tables, 35 sources, 2 annexes. Keywords: coal gasification combined cycle plant, a gas turbine plant, the product gas analysis, waste heat boiler, performance indicators. The object of this study is to CCGT running on syngas. The purpose of work - performance analysis of a CCGT with a gas turbine, operating on syngas. The study was carried out to study different methods of coal gasification; selects the estimated PSU circuit with gasification; conducted calculation and composition of the product gas characteristics and the definition of the main indicators of the thermal efficiency of the CCGT. The survey was made the analysis of the efficiency of the combined-cycle plant

    Внедрение корпоративной системы управления проектами для реализации стратегических проектов компании

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    В целях реализации Восточной газовой программы ООО "Газпром трансгаз Томск" разработало Стратегию развития до 2020 г. и План организационно-технических мероприятий. Для успешного выполнения перспективных задач в организации формируется новая, современная система управления - корпоративная система управления проектами. Разработана методика внедрения корпоративной системы управления проектами, состав системы, определены ключевые участники и критические факторы успеха, выполнен расчет экономической эффективности проекта
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