106 research outputs found

    A Dynamical (e,2e) Investigation into the Ionization of the Outermost Orbitals of R-Carvone

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    We report an experimental and theoretical investigation into the dynamics of electron-impact ionization of R-carvone. Experimental triple differential cross sections are obtained in asymmetric coplanar kinematic conditions for the ionization of the unresolved combination of the three outermost molecular orbitals (41a-39a) of R-carvone. These cross sections are compared with theoretical cross sections calculated within a molecular 3-body distorted wave (M3DW) framework employing either a proper orientation average or orbital average to account for the random orientation of the molecule probed in the experiment. Here, we observe that the overall scattering behavior observed in the experiment is fairly well reproduced within the M3DW framework when implementing the proper average over orientations. The character of the ionized orbitals also provides some qualitative explanation for the observed scattering behavior. This represents substantial progress when trying to describe the scattering dynamics observed for larger molecules under intermediate-impact energy and asymmetric energy sharing scattering conditions

    Inferring fish escape behaviour in trawls based on catch comparison data: Model development and evaluation based on data from Skagerrak, Denmark

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    During the fishing process, fish react to a trawl with a series of behaviours that often are species and size specific. Thus, a thorough understanding of fish behaviour in relation to fishing gear and a scientific understanding of the ability of different gear designs to utilize or stimulate various behavioural patterns during the catching process are essential for developing more efficient, selective, and environmentally friendly trawls. Although many behavioural studies using optical and acoustic observation systems have been conducted, harsh observation conditions on the fishing grounds often hamper the ability to directly observe fish behaviour in relation to fishing gear. As an alternative to optical and acoustic methods, we developed and applied a new mathematical model to catch data to extract detailed and quantitative information about species- and size-dependent escape behaviour in towed fishing gear such as trawls. We used catch comparison data collected with a twin trawl setup; the only difference between the two trawls was that a 12 m long upper section was replaced with 800 mm diamond meshes in one of them. We investigated the length-based escape behaviour of cod (Gadus morhua), haddock (Melanogrammus aeglefinus), saithe (Pollachius virens), witch flounder (Glyptocephalus cynoglossus), and lemon sole (Microstomus kitt) and quantified the extent to which behavioural responses set limits for the large mesh panel's selective efficiency. Around 85% of saithe, 80% of haddock, 44% of witch flounder, 55% of lemon sole, and 55% of cod (below 68 cm) contacted the large mesh panel and escaped. We also demonstrated the need to account for potential selectivity in the trawl body, as it can bias the assessment of length-based escape behaviour. Our indirect assessment of fish behaviour was in agreement with the direct observations made for the same species in a similar section of the trawl body reported in the literature

    NF-kappaB mediates the survival of human bronchial epithelial cells exposed to cigarette smoke extract

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    Background: We have previously reported that low concentrations of cigarette smoke extract induce DNA damage without leading to apoptosis or necrosis in human bronchial epithelial cells (HBECs), and that IL-6/STAT3 signaling contributes to the cell survival. Since NF-kappa B is also involved in regulating apoptosis and cell survival, the current study was designed to investigate the role of NF-kappa B in mediating cell survival in response to cigarette smoke exposure in HBECs. Methods: Both the pharmacologic inhibitor of NF-kappa B, curcumin, and RNA interference targeting p65 were used to block NF-kappa B signaling in HBECs. Apoptosis and cell survival were then assessed by various methods including COMET assay, LIVE/DEAD Cytotoxicity/Viability assay and colony formation assay. Results: Cigarette smoke extract (CSE) caused DNA damage and cell cycle arrest in S phase without leading to apoptosis in HBECs as evidenced by TUNEL assay, COMET assay and DNA content assay. CSE stimulated NF-kappa B -DNA binding activity and up-regulated Bcl-XL protein in HBECs. Inhibition of NF-kappa B by the pharmacologic inhibitor curcumin (20 mu M) or suppression of p65 by siRNA resulted in a significant increase in cell death in response to cigarette smoke exposure. Furthermore, cells lacking p65 were incapable of forming cellular colonies when these cells were exposed to CSE, while they behaved normally in the regular culture medium. Conclusion: The current study demonstrates that CSE activates NF-kappa B and up-regulates Bcl-XL through NF-kappa B activation in HBECs, and that CSE induces cell death in cells lacking p65. These results suggest that activation of NF-kappa B regulates cell survival following DNA damage by cigarette smoke in human bronchial epithelial cells.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000260432600001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Respiratory SystemSCI(E)28ARTICLEnull

    Patterns of Spatial Variation of Assemblages Associated with Intertidal Rocky Shores: A Global Perspective

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    Assemblages associated with intertidal rocky shores were examined for large scale distribution patterns with specific emphasis on identifying latitudinal trends of species richness and taxonomic distinctiveness. Seventy-two sites distributed around the globe were evaluated following the standardized sampling protocol of the Census of Marine Life NaGISA project (www.nagisa.coml.org). There were no clear patterns of standardized estimators of species richness along latitudinal gradients or among Large Marine Ecosystems (LMEs); however, a strong latitudinal gradient in taxonomic composition (i.e., proportion of different taxonomic groups in a given sample) was observed. Environmental variables related to natural influences were strongly related to the distribution patterns of the assemblages on the LME scale, particularly photoperiod, sea surface temperature (SST) and rainfall. In contrast, no environmental variables directly associated with human influences (with the exception of the inorganic pollution index) were related to assemblage patterns among LMEs. Correlations of the natural assemblages with either latitudinal gradients or environmental variables were equally strong suggesting that neither neutral models nor models based solely on environmental variables sufficiently explain spatial variation of these assemblages at a global scale. Despite the data shortcomings in this study (e.g., unbalanced sample distribution), we show the importance of generating biological global databases for the use in large-scale diversity comparisons of rocky intertidal assemblages to stimulate continued sampling and analyses
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