145 research outputs found

    Circum-Arctic lithosphere-basin evolution : An overview

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    Acknowledgements The Special Issue editors thank the contributors for their hard work and dedication in the preparation of the papers presented here, and also Victoria Pease for her active support throughout the process and in particular in co-convening the conference session giving rise to this Special Issue. In particular, we thank the Editor-in-chief, Dr. Rob Govers for his patience, guidance and valued advice throughout the process. Also, we appreciate the work of the Tectonophysics editorial and production teams for bringing the Special Issue to print. R. Ernst, G. Oakey and an anonymous reviewer provided a multitude of helpful suggestions to improve the manuscript. This Special Issue is a contribution to the Geological Survey of Canada's Geomapping for Energy and Minerals (GEM2) Program, Canada's Extended Continental Shelf Program, and the Circum-Arctic Lithosphere Evolution (CALE) network. ESS Contribution No. 20160152.Peer reviewedPostprin

    Investigation of a gauge theory in general relativity /

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    The evaluation of a synthetic material for use as a wave protection agent on irrigation dams

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    This report presents the results of a field and laboratory testing program to evaluate the performance of a slope protection method utilizing a new synthetic fabric material in the form of soil filled bags. The field study was performed to evaluate the feasibility of filling and placing the bags on an operational irrigation darn using equipment and resources available to a typical farmer. Test sections on the dam were monitored to determine the amount of wave erosion of both unprotected and protected slopes of the dam. Tensile strength tests were performed on samples of the fabric. The results of the strength tests indicate the durability of the system. Laboratory immersion tests were conducted on two soil materials used to fill the bags. The results of the immersion tests were then compared to the field performance of each material in the bags. The results of this investigation indicate that the system is readily installed on irrigation dams and offers excellent slope protection. The factors which influence the practicality of the system include the cost of alternate slope protection methods, the position of the irrigation dam in relation to local winds and the availability of fill material for the bags. A medium-scale laboratory model study was performed on a new synthetic fabric designed to be used in the form of soil-filled sand pillows in order to determine the relationship that affect the stability of the pillows and to determine basic design criteria for the protection system. The model testing of the sand pillow system was performed to evaluate the parameters that affect the stability of the pillows when placed on an embankment slope. The results of the model investigation were consolidated and analyzed to develop design criteria for the individual pillows. The results of the model study investigation indicate that the stability of sand pillows is primarily a function of wave height, wave period, embankment slope angle, and individual sand pillow weight. A possible design equation was developed for a silty clay soil such that the wave height calculated for a given reservoir could be utilized to determine the weight of the individual sand pillow necessary to economically and effectively protect the embankment. The results of the laboratory and field evaluation investigation indicate that the sand pillow method offers excellent slope protection. However, since some soils appear to be readily lost through fabric when subjected to repeated wave action, some limiting minimum particle size specification is required in order to prevent unnecessary maintenance of the system.Project # B-122-MO Agreement # 14-34-0001-809

    FRET-Based Quantum Dot Immunoassay for Rapid and Sensitive Detection of Aspergillus amstelodami

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    In this study, a fluorescence resonance energy transfer (FRET)-based quantum dot (QD) immunoassay for detection and identification of Aspergillus amstelodami was developed. Biosensors were formed by conjugating QDs to IgG antibodies and incubating with quencher-labeled analytes; QD energy was transferred to the quencher species through FRET, resulting in diminished fluorescence from the QD donor. During a detection event, quencher-labeled analytes are displaced by higher affinity target analytes, creating a detectable fluorescence signal increase from the QD donor. Conjugation and the resulting antibody:QD ratios were characterized with UV-Vis spectroscopy and QuantiT protein assay. The sensitivity of initial fluorescence experiments was compromised by inherent autofluorescence of mold spores, which produced low signal-to-noise and inconsistent readings. Therefore, excitation wavelength, QD, and quencher were adjusted to provide optimal signal-to-noise over spore background. Affinities of anti-Aspergillus antibody for different mold species were estimated with sandwich immunoassays, which identified A. fumigatus and A. amstelodami for use as quencher-labeled- and target-analytes, respectively. The optimized displacement immunoassay detected A. amstelodami concentrations as low as 103 spores/mL in five minutes or less. Additionally, baseline fluorescence was produced in the presence of 105 CFU/mL heat-killed E. coli O157:H7, demonstrating high specificity. This sensing modality may be useful for identification and detection of other biological threat agents, pending identification of suitable antibodies. Overall, these FRET-based QD-antibody biosensors represent a significant advancement in detection capabilities, offering sensitive and reliable detection of targets with applications in areas from biological terrorism defense to clinical analysis

    Regulation of smooth muscle Ī±-actin expression and hypertrophy in cultured mesangial cells

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    Regulation of smooth muscle Ī±-actin expression and hypertrophy in cultured mesangial cells.BackgroundMesangial cells during embryonic development and glomerular disease express smooth muscle Ī±-actin (Ī±-SMA). We were therefore surprised when cultured mesangial cells deprived of serum markedly increased expression of Ī±-SMA. Serum-deprived mesangial cells appeared larger than serum-fed mesangial cells. We hypothesized that Ī±-SMA expression may be more reflective of mesangial cell hypertrophy than hyperplasia.MethodsHuman mesangial cells were cultured in medium alone or with fetal bovine serum, thrombin, platelet-derived growth factor-BB (PDGF-BB) and/or transforming growth factor-Ī²1 (TGF-Ī²1). Ī±-SMA expression was examined by immunofluorescence, Western blot, and Northern blot analysis. Cell size was analyzed by forward light scatter flow cytometry.ResultsĪ±-SMA mRNA was at least tenfold more abundant after three to five days in human mesangial cells plated without serum, but Ī²-actin mRNA was unchanged. Serum-deprived cells contained 5.3-fold more Ī±-SMA after three days and 56-fold more after five days by Western blot. Serum deprivation also increased Ī±-SMA in rat and mouse mesangial cells. The effects of serum deprivation on Ī±-SMA expression were reversible. Mesangial cell mitogens, thrombin or PDGF-BB, decreased Ī±-SMA, but TGF-Ī²1 increased Ī±-SMA expression and slowed mesangial cell proliferation in serum-plus medium. Flow cytometry showed that serum deprivation or TGF-Ī²1 treatment caused mesangial cell hypertrophy. PDGF-BB, thrombin, or thrombin receptor-activating peptide blocked hypertrophy in response to serum deprivation.ConclusionsWe conclude that increased Ī±-SMA expression in mesangial cells reflects cellular hypertrophy rather than hyperplasia
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