3,227 research outputs found

    Biological actions and molecular effects of resveratrol, pterostilbene, and 3′-hydroxypterostilbene

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    AbstractStilbenes are a class of polyphenolic compounds, naturally found in a wide variety of dietary sources such as grapes, berries, peanuts, red wine, and some medicinal plants. There are several well-known stilbenes including trans-resveratrol, pterostilbene, and 3′-hydroxypterostilbene. The core chemical structure of stilbene compounds is 1,2-diphenylethylene. Recently, stilbenes have attracted extensive attention and interest due to their wide range of health-beneficial effects such as anti-inflammation, -carcinogenic, -diabetes, and -dyslipidemia activities. Moreover, accumulating in vitro and in vivo studies have reported that stilbene compounds act as inducers of multiple cell-death pathways such as apoptosis, cell cycle arrest, and autophagy for chemopreventive and chemotherapeutic agents in several types of cancer cells. The aim of this review is to highlight recent molecular findings and biological actions of trans-resveratrol, pterostilbene, and 3′-hydroxypterostilbene

    Exploring the phase space of multiple states in highly turbulent Taylor-Couette flow

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    We investigate the existence of multiple turbulent states in highly turbulent Taylor-Couette flow in the range of Ta=1011\mathrm{Ta}=10^{11} to 9â‹…10129\cdot10^{12}, by measuring the global torques and the local velocities while probing the phase space spanned by the rotation rates of the inner and outer cylinder. The multiple states are found to be very robust and are expected to persist beyond Ta=1013\mathrm{Ta}=10^{13}. The rotation ratio is the parameter that most strongly controls the transitions between the flow states; the transitional values only weakly depend on the Taylor number. However, complex paths in the phase space are necessary to unlock the full region of multiple states. Lastly, by mapping the flow structures for various rotation ratios in a Taylor-Couette setup with an equal radius ratio but a larger aspect ratio than before, multiple states were again observed. Here, they are characterized by even richer roll structure phenomena, including, for the first time observed in highly turbulent TC flow, an antisymmetrical roll state.Comment: 9 pages, 7 figure

    Prevalence of Tidal Interactions among Local Seyfert Galaxies

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    No mechanisms have hitherto been conclusively demonstrated to be responsible for initiating optically-luminous nuclear (Seyfert) activity in local disk galaxies. Only a small minority of such galaxies are visibly disturbed in optical starlight, with the observed disturbances being at best marginally stronger than those found in matched samples of inactive galaxies. Here, we report the first systematic study of an optically-selected sample of twenty-three active galaxies in atomic hydrogen (HI) gas, which is the most sensitive and enduring tracer known of tidal interactions. Eighteen of these galaxies are (generally) classified as Seyferts, with over half (and perhaps all) having [OIII] luminosities within two orders of magnitude of Quasi-Stellar Objects. Only ~28% of these Seyfert galaxies are visibly disturbed in optical DSS2 images. By contrast, ~94% of the same galaxies are disturbed in HI, in nearly all cases not just spatially but also kinematically on galactic (>~20 kpc) scales. In at least ~67% and perhaps up to ~94% of cases, the observed HI disturbances can be traced to tidal interactions with neighboring galaxies detected also in HI. The majority of these neighboring galaxies have projected separations of <~ 100 kpc and differ in radial velocities by <~100 km/s from their respective Seyfert galaxies, and many have optical luminosities ranging from the Small to Large Magellanic Clouds. In a companion paper, we show that only ~15% of a matched control sample of inactive galaxies display comparable HI disturbances. Our results suggest that: i) most Seyfert galaxies (with high nuclear luminosities) have experienced tidal interactions in the recent past; ii) in most cases, these tidal interactions are responsible for initiating events that lead to their nuclear activity.Comment: 64 pages, 44 figures, accepted for publication in ApJ. Changes: Nothing is changed except that the paper was compiled differently to reduce the number of pages. To be friendly to the Earth forest, you could also choose to only print the text part of the paper and view images on line. (see http://www.astro.virginia.edu/~ck2v/paper/

    North American Winter Dipole: Observed and Simulated Changes in Circulations

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    In recent years, a pair of large-scale circulation patterns consisting of an anomalous ridge over northwestern North America and trough over northeastern North America was found to accompany extreme winter weather events such as the 2013–2015 California drought and eastern U.S. cold outbreaks. Referred to as the North American winter dipole (NAWD), previous studies have found both a marked natural variability and a warming-induced amplification trend in the NAWD. In this study, we utilized multiple global reanalysis datasets and existing climate model simulations to examine the variability of the winter planetary wave patterns over North America and to better understand how it is likely to change in the future. We compared between pre- and post-1980 periods to identify changes to the circulation variations based on empirical analysis. It was found that the leading pattern of the winter planetary waves has changed, from the Pacific–North America (PNA) mode to a spatially shifted mode such as NAWD. Further, the potential influence of global warming on NAWD was examined using multiple climate model simulations

    Phytoremediation of Soil Contaminated with Crude Oil Using Mucuna Bracteata

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    This study examines the ability of Mucuna bracteata DC. to remediate soil contaminated with increasing levels of crude oil up to 20%. It also investigates the effect of fertilizer application on crude oil degradation. Changes in crude oil concentrations, pH and moisture of the soil in eight experimental pots were tracked over a period of 9 weeks. The crude oil levels in soil were analysed as Total Petroleum Hydrocarbons (TPHs) using the UV-Vis spectrophotometer. The study revealed the capacity of Mucuna bracteata to phytoremediate soil contaminated with crude oil in all experimental pots though the plant died at 20% contamination towards the end of the experiment. The plant survived up to 15% contamination with that in the fertilized pot showing better physical conditions. In all instances, fertilized pots showed higher rates of crude oil reduction. The amounts of crude oil degraded in fertilized pots were also higher except at 20% contamination. The soil pH varied over a narrow range throughout the experimental period. Moisture of soil contaminated with 15% and 20% crude oil was higher than that contaminated with 5% and 10% crude oil. Mucuna bracteata showed signs of phytoextraction which can be subject to further study. This study contributed a new candidate of phytoremediation for soil contaminated with high level of crude oil
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