2,367 research outputs found

    Method AHP to Flood Risk Map Approach

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    The phenomenon of flooding is a natural event, given by the extravasation of water to the river bed. The main objective of this study was the analysis of susceptibility to flooding of the basin of Uraim River in the municipality of Paragominas ParĂĄ state based on the physical characteristics and morphometric basin. It used the Analysis method Hierarchical method for generating gas order susceptibility map of the basin. The AHP technique used to determine map algebra contributed to the analysis of the susceptibility to floods and was effective because it reduces and simplifies the proposed problem, which minimizes the errors of judgment during the process

    Comparative analysis of homology models of the Ah receptor ligand binding domain: Verification of structure-function predictions by site-directed mutagenesis of a nonfunctional receptor

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    The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor that mediates the biological and toxic effects of a wide variety of structurally diverse chemicals, including the toxic environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). While significant interspecies differences in AHR ligand binding specificity, selectivity, and response have been observed, the structural determinants responsible for those differences have not been determined, and homology models of the AHR ligand-binding domain (LBD) are available for only a few species. Here we describe the development and comparative analysis of homology models of the LBD of 16 AHRs from 12 mammalian and nonmammalian species and identify the specific residues contained within their ligand binding cavities. The ligand-binding cavity of the fish AHR exhibits differences from those of mammalian and avian AHRs, suggesting a slightly different TCDD binding mode. Comparison of the internal cavity in the LBD model of zebrafish (zf) AHR2, which binds TCDD with high affinity, to that of zfAHR1a, which does not bind TCDD, revealed that the latter has a dramatically shortened binding cavity due to the side chains of three residues (Tyr296, Thr386, and His388) that reduce the amount of internal space available to TCDD. Mutagenesis of two of these residues in zfAHR1a to those present in zfAHR2 (Y296H and T386A) restored the ability of zfAHR1a to bind TCDD and to exhibit TCDD-dependent binding to DNA. These results demonstrate the importance of these two amino acids and highlight the predictive potential of comparative analysis of homology models from diverse species. The availability of these AHR LBD homology models will facilitate in-depth comparative studies of AHR ligand binding and ligand-dependent AHR activation and provide a novel avenue for examining species-specific differences in AHR responsiveness. © 2013 American Chemical Society

    IS1111 insertion sequences of Coxiella burnetii: characterization and use for repetitive element PCR-based differentiation of Coxiella burnetii isolates

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    <p>Abstract</p> <p>Background</p> <p><it>Coxiella burnetii </it>contains the IS<it>1111 </it>transposase which is present 20 times in the Nine Mile phase I (9Mi/I) genome. A single PCR primer that binds to each IS element, and primers specific to a region ~500-bp upstream of each of the 20 IS<it>1111 </it>elements were designed. The amplified products were characterized and used to develop a repetitive element PCR genotyping method.</p> <p>Results</p> <p>Isolates Nine Mile phase II, Nine Mile RSA 514, Nine Mile Baca, Scottish, Ohio, Australian QD, Henzerling phase I, Henzerling phase II, M44, KAV, PAV, Q238, Q195 and WAV were tested by PCR and compared to 9Mi/I. Sequencing was used to determine the exact differences in isolates which lacked specific IS elements or produced PCR products of differing size. From this data, an algorithm was created utilizing four primer pairs that allows for differentiation of unknown isolates into five genomic groups. Additional isolates (Priscilla Q177, Idaho Q, Qiyi, Poker Cat, Q229 and Q172) and nine veterinary samples were characterized using the algorithm which resulted in their placement into three distinct genomic groups.</p> <p>Conclusion</p> <p>Through this study significant differences, including missing elements and sequence alterations within and near IS element coding regions, were found between the isolates tested. Further, a method for differentiation of <it>C. burnetii </it>isolates into one of five genomic groups was created. This algorithm may ultimately help to determine the relatedness between known and unknown isolates of <it>C. burnetii</it>.</p

    Early Neoproterozoic limestones from the Gwna Group, Anglesey

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    Limestone megaclasts up to hundreds of metres in size are present within the Gwna Group mélange, North Wales, UK. The mélange has been interpreted as part of a Peri-Gondwanan fore-arc accretionary complex although the age of deposition remains contentious, proposals ranging from Neoproterozoic to Early Ordovician. This paper uses strontium isotope chemostratigraphy to establish the age of the limestone blocks and thus provide a maximum age constraint on mélange formation. Results show that, although the carbonates are locally dolomitized, primary 87Sr/86Sr ratios can be identified and indicate deposition sometime between the late Tonian and earliest Cryogenian. This age is older than that suggested by stromatolites within the limestone and indicates that the limestone did not form as cap carbonate deposits

    Novel 2-amino-isoflavones exhibit aryl hydrocarbon receptor agonist or antagonist activity in a species/cell-specific context

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    The aryl hydrocarbon receptor (AhR) mediates the induction of a variety of xenobiotic metabolism genes. Activation of the AhR occurs through binding to a group of structurally diverse compounds, most notably dioxins, which are exogenous ligands. Isoflavones are part of a family which include some well characterised endogenous AhR ligands. This paper analysed a novel family of these compounds, based on the structure of 2-amino-isoflavone. Initially two luciferase-based cell models, mouse H1L6.1c2 and human HG2L6.1c3, were used to identify whether the compounds had AhR agonistic and/or antagonistic properties. This analysis showed that some of the compounds were weak agonists in mouse and antagonists in human. Further analysis of two of the compounds, Chr-13 and Chr-19, was conducted using quantitative real-time PCR in rat H4IIE and human MCF-7 cells. The results indicated that Chr-13 was an agonist in rat but an antagonist in human cells. Chr-19 was shown to be an agonist in rat but more interestingly, a partial agonist in human. Luciferase induction results not only revealed that subtle differences in the structure of the compound could produce species-specific differences in response but also dictated the ability of the compound to be an AhR agonist or antagonist. Substituted 2-amino-isoflavones represent a novel group of AhR ligands that must differentially interact with the AhR ligand binding domain to produce their species-specific agonist or antagonist activity and future ligand binding analysis and docking studies with these compounds may provide insights into the differential mechanisms of action of structurally similar compounds

    Jogging not running: A narrative approach to exploring ‘exercise as leisure’ after a life in elite football

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    As research has shown, former elite athletes often struggle to adapt to aspects of their post-sport lives. This can include the management of their identities, dealing with the uncertainty of their new roles, and negotiating the changes that occur to their bodies. In this paper we discuss an under-reported challenge facing retired athletes: how to manage their ongoing relationship with exercise. To address this issue we adopted a narrative approach, based on the first author’s experiences as a former football player, to provide a socio-cultural reading of the various challenges involved in the transition from exercise as a vocation to a leisure activity. We suggest that these stories demonstrate that in retirement, former athletes’ docility, while seemingly advantageous, can also be a significant obstacle to developing alternative meanings for exercise, including as a potential re-creative or leisure activity that can become meaningful and important in its own right

    Options for state chemicals policy reform:A resource guide

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    Analysis of Mercury Grouping in Soil in the Foz of the TapajĂłs River, Amazonia-Brazil

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    The region of Santarém, in the state of Parå, was chosen to carry out this research because it is at the center of discussions of mercury contamination in the Amazon. The objective of this paper is the analysis of Hg and Methyl-Hg speciation in soil. The methodological procedures to determine the total mercury and methylHg were carried out by means of samples, which were submitted to acid digestion and determinations of Hg performed by Atomic Absorption Spectrophotometry with cold vapor generation. The evaluation of the concentrations of mercury in the sampled and depth points was performed with the aid of cluster analysis, using the Hierarchical clustering method. The results obtained indicate that the total mercury in soil showed very high values in the analysis of total mercury with granulometry for fine fraction and gross fraction, indicating an urgent mobilization and political action in the municipal, state and federal spheres regarding the exposure of the environment environment to the mercury detected
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