5,583 research outputs found

    Bedrock and soil geochemistry influence the content of chemical elements in wild edible mushrooms (Morchella group) from South Italy (Sicily)

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    Chemical elements in the samples of wild edible mushrooms of the Morchellagroup collected from different unpolluted Sicilian sites was analyzed by the ICP-MS (method) to detect the content of their minerals and determine whether soil geology and geochemistry can influence the chemical composition in fungi. Results showed that the mushroom samples mainly contained a high concentration of K and P and a wide variety of minor and trace elements (V, Mo, Pb, Ce, Cs, Zr), including heavy metals. Statistical analysis showed that the mushrooms differed in their content of minor and trace elements based on the geological/geographic site of origin. Comparison with other studies showed differences in the content detected in the Sicilian morels with those collected from other geographical sites. Conversely, dif-ferent fungal species collected from similar geological sites in Sicily showed different patterns of accumulation of the elements confirming that bioconcentration in fungi is species- and site-dependent

    Polyethylene under tensile load: strain energy storage and breaking of linear and knotted alkanes probed by first-principles molecular dynamics calculations

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    The mechanical resistance of a polyethylene strand subject to tension and the way its properties are affected by the presence of a knot is studied using first-principles molecular dynamics calculations. The distribution of strain energy for the knotted chains has a well-defined shape that is very different from the one found in the linear case. The presence of a knot significantly weakens the chain in which it is tied. Chain rupture invariably occurs just outside the entrance to the knot, as is the case for a macroscopic rope.Comment: 8 pages, 11 figures, to appear on J. Chem. Phy

    Transcriptional inhibition of type I collagen gene expression in scleroderma fibroblasts by the antineoplastic drug ecteinascidin 743.

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    We previously showed that COL1A1 expression is up-regulated at the transcriptional level in systemic sclerosis (SSc) fibroblasts and that the CCAAT-binding factor (CBF) is involved in this increased expression. Ecteinascidin 743 (ET-743) is a chemotherapeutic agent that binds with sequence specificity to the minor groove of DNA and inhibits CBF-mediated transcriptional activation of numerous genes. Therefore, we examined the effects of ET-743 on the increased COL1A1 expression in SSc fibroblasts. The drug caused a potent and dose-dependent inhibition of type I collagen biosynthesis, which reached 70-90% at 700 pM without affecting cell viability. The same drug concentration caused 60-80% reduction in COL1A1 mRNA levels. The stability of the corresponding transcripts was not affected. In vitro nuclear transcription assays demonstrated a 54% down-regulation of COL1A1 transcription. Transient transfections with COL1A1 promoter constructs containing the specific CBF binding sequence into SSc cells previously treated with 700 pM ET-743 failed to show an effect on COL1A1 promoter activity. Furthermore, ET-743 did not affect the binding of CBF or Sp1 transcription factors to their cognate COL1A1 elements. However, treatment with 700 pM ET-743 of stably transfected NIH 3T3 cells expressing a human type II procollagen gene under the control of the human COL1A1 promoter caused a greater than 50% reduction in the production of type II procollagen and a similar decrease in the corresponding type II procollagen transcripts. These results indicate that ET-743 is a potent inhibitor of COL1A1 transcription. However, this effect cannot be explained by a direct effect on CBF binding to the COL1A1 promoter. Although the exact mechanisms responsible for the transcriptional inhibition of COL1A1 by ET-743 are not apparent, our observations suggest that the drug may be an effective agent to decrease collagen overproduction in SSc and other fibrotic diseases

    High resolution spectroscopy of the three dimensional cosmic web with close QSO groups

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    We study the three-dimensional distribution of matter at z~2 using high resolution spectra of QSO pairs and simulated spectra drawn from cosmological hydro-dynamical simulations. We present a sample of 15 QSOs, corresponding to 21 baselines of angular separations evenly distributed between ~1 and 14 arcmin, observed with the Ultraviolet and Visual Echelle Spectrograph (UVES) at the European Southern Observatory-Very Large Telescope (ESO-VLT). The observed correlation functions of the transmitted flux in the HI Lya forest transverse to and along the line of sight are in agreement, implying that the distortions in redshift space due to peculiar velocities are relatively small and - within the relatively large error bars - not significant. The clustering signal is significant up to velocity separations of ~300 km/s, corresponding to about 5 h^{-1} comoving Mpc. Compatibility at the 2 sigma level has been found both for the Auto- and Cross-correlation functions and for the set of the Cross correlation coefficients. The analysis focuses in particular on two QSO groups of the sample. Searching for alignments in the redshift space between Lya absorption lines belonging to different lines of sight, it has been possible to discover the presence of a wide HI structures extending over about ten Mpc in comoving space, and give constraints on the sizes of two cosmic under-dense regions in the intergalactic medium.Comment: Accepted by MNRAS, version matching the published on

    Memo to DU Provost and Chancellor

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    Memorandum sent to the University of Denver\u27s Provost and Chancellor about interest in a study on John Evans and the Sand Creek Massacre

    The Ostrogoths in Italy

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    The paper intends to establish a summary of the policies of Theoderic, of his achievements and his failures, as well as the basic principies of his politics, which were far from negative to the evolution of his kingdom in Italy

    Report of Meeting with Chancellor and Provost

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    Meeting notes regarding formation of a John Evans study
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