121,763 research outputs found

    Antioxidant role of metallothioneins: a comparatie overview.

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    Metallothioneins (MTs) are sulfhydryl-rich proteins binding essential and non-essential heavy metals. MTs display in vitro oxyradical scavenging capacity, suggesting that they may specifically neutralize hydroxyl radicals. Yet, this is probably an oversimplified view, as MTs represent a superfamily of widely differentiated metalloproteins. MT antioxidant properties mainly derive from sulfhydryl nucleophilicity, but also from metal complexation. Binding of transition metals displaying Fenton reactivity (Fe,Cu) can reduce oxidative stress, whereas their release exacerbates it. In vertebrates, MT gene promoters contain metal (MRE) and glucocorticoid response elements (GRE), Sp and AP sequences, but also antioxidant response elements (ARE). MT neosynthesis is induced by heavy metals, cytokines, hormones, but also by different oxidants and prooxidants. Accordingly, MT overexpression increases the resistance of tissues and cells to oxidative stress. As for invertebrates, data from the mussel show that MT can actually protect against oxidative stress, but is poorly inducible by oxidants. In yeast, there is a Cu(I)-MT that in contrast to mammalCu-MT exhibits antioxidant activity, possibly due to differences in metal binding domains. Finally, as the relevance of redox processes in cell signaling is becoming more and more evident, a search for MT effects on redox signaling could represent a turning point in the understanding of the functional role of these protein

    A Multi-Language Comparison of Influences on Author Verification using Character N-Grams

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    We create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc

    Appropriate Similarity Measures for Author Cocitation Analysis

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    We provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis

    Chromosomal mapping of human cytokeratin 13 gene (KRT13).

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    In the present study the human cytokeratin 13 gene (KRT13), encoding a polypeptide characteristic of internal stratified epithelia, has been mapped with the help of the polymerase chain reaction and somatic cell hybrids to chromosome 17. In situ hybridization of a KRT13 cDNA probe to metaphase chromosomes allowed the assignment of the KRT13 gene within the q12-q21.2 region of chromosome 17

    RFLP discordance in a PKU family due to a deletion in the PAH gene

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    : We have previously reported preliminary data on a PKU family showing a discordant segregation of Pvu II (b) alleles at the PAH locus. A combination of several restriction enzymes and probe C2.6 (Intron 2) as well as STR typing were used to dissect the molecular structure of the PAH gene around exon 3. In this family, the results of this analysis and a re-examination of the physical map of the 5'-end of the gene provided strong evidence for the occurrence of a deletion removing exon 3. The "Sicilian" (approximately 2.5 kb) and "Yemenite Jew" (6.7 kb) deletions, the latter one also deleting exon 3, are different in terms of both the 5'-end breakpoint and apparent length. This study, besides adding a new member to the long and increasing list of nearly 200 PAH gene mutations, also proposes to undertake a careful evaluation of RFLP discordances incidentally detected at the PAH locus
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