635 research outputs found

    Reaction of chromium(VI) with glutathione or with hydrogen peroxide: identification of reactive intermediates and their role in chromium(VI)-induced DNA damage.

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    The types of reactive intermediates generated upon reduction of chromium(VI) by glutathione or hydrogen peroxide and the resulting DNA damage have been determined. In vitro, reaction of chromium(VI) with glutathione led to formation of two chromium(V) complexes and the glutathione thiyl radical. When chromium(VI) was reacted with DNA in the presence of glutathione, chromium-DNA adducts were obtained, with no DNA strand breakage. The level of chromium-DNA adduct formation correlated with chromium(V) formation. Reaction of chromium(VI) with hydrogen peroxide led to formation of hydroxyl radical. No chromium(V) was detectable at 24 degrees C (297 K); however, low levels of the tetraperoxochromium(V) complex were detected at 77 K. Reaction of chromium(VI) with DNA in the presence of hydrogen peroxide produced significant DNA strand breakage and the 8-hydroxydeoxyguanosine adduct, whose formation correlated with hydroxyl radical production. No significant chromium-DNA adduct formation was detected. Thus, the nature of chromium(VI)-induced DNA damage appears to be dependent on the reactive intermediates, i.e. chromium(V) or hydroxyl radical, produced during the reduction of chromium(VI)

    Wage differentials and their determinants in US tourism and tourism-associated industries

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    This paper examines variations in wages for tourism related industries in the US for the period 2004-2009. It critically assesses the extent to which tourism related activities conform to their low wage stereotype and finds this to be true in general but not universally. It then considers the possibility that wages in US tourism related industries can be explained by observable characteristics of these industries. Recent research has suggested that the use of wage data at the level of highly detailed occupations is an effective alternative to other ways of capturing underlying skill differences. In line with this literature data from the US Occupational Employment Statistics (OES) were used to provide this detail. The results strongly support the importance of difference between occupations in wages in understanding differences between industries. They also support the importance of a number of industry characteristics including profitability, multi-factor productivity and demand growth. The paper also considers the relevance of an industry wage premium or discount for tourism related activities in the US over the same period. To assess this it estimates an industry wage model separately for five individual occupations across all industries which employ the occupation concerned. Within the small number of occupations covered the analysis find that workers in the two more highly paid occupations exhibit evidence of a tourism related discount but that workers in the three more lowly paid occupations exhibit a tourism related wage premium

    Can Europe recover without credit?

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    Data from 135 countries covering five decades suggests that creditless recoveries, in which the stock of real credit does not return to the pre-crisis level for three years after the GDP trough, are not rare and are characterised by remarkable real GDP growth rates: 4.7 percent per year in middle-income countries and 3.2 percent per year in high-income countries. However, the implications of these historical episodes for the current European situation are limited, for two main reasons. First, creditless recoveries are much less common in highincome countries, than in low-income countries which are financially undeveloped. European economies heavily depend on bank loans and research suggests that loan supply played a major role in the recent weak credit performance of Europe. There are reasons to believe that, despite various efforts, normal lending has not yet been restored. Limited loan supply could be disruptive for the European economic recovery and there has been only a minor substitution of bank loans with debt securities. Second, creditless recoveries were associated with significant real exchange rate depreciation, which has hardly occurred so far in most of Europe. This stylised fact suggests that it might be difficult to re-establish economic growth in the absence of sizeable real exchange rate depreciation, if credit growth does not return

    Different patterns of labour market integration by migration motivation in Europe: the role of host country human capital

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    We study whether individual decisions to invest in the host country, namely obtaining equivalent qualifications, improving language skills, or naturalisation explain differences in labour market integration between migrants depending on their initial motivation. We use cross-national European data from the 2008 ad-hoc module of the Labour Force Survey to analyse migrant gaps in labour market participation, employment, occupational status and precarious employment. We find that different rates of and returns to host country human capital explain a substantial part of the improvements in labour market outcomes with years of residence, particularly for non-economic migrants who experience faster growth on average

    Tetra-methoxystilbene modulates ductal growth of the developing murine mammary gland

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    Extensive data suggest that estradiol contributes to the development of breast cancer by acting as a mitogen and exerting direct genotoxic effects after enzymatic conversion to 4-hydroxyestradiol (4-OHE2) via cytochrome P450 1B1 (CYP1B1). The mammary gland, ovary, and uterus all express CYP1B1. Overexpression of this enzyme has been associated with an increased risk of breast cancer and blockade might reduce this carcinogenic effect. For this reason, we conducted systematic in vitro and in vivo studies of a CYP1B1 inhibitor, TMS (2,3',4,5'-tetramethoxystilbene). We found that TMS blocked the enzymatic conversion of radiolabeled estradiol to both 2-hydroxyestradiol (2-OHE2) and 4-OHE2, but did not inhibit Cyp1b1 message formation. In vivo studies using mass spectrometry showed that TMS inhibited formation of 2-OHE2 and 4-OHE2 and the resulting estrogen-DNA adducts. To examine its biologic actions in vivo, we investigated whether TMS could block the hyperplastic changes that occur in the developing breast of aromatase-transfected mice. We found that TMS induced a significant reduction of ductal structures in mice less than 6 months in age. In older mice, no reduction in breast morphology occurred. These latter studies uncovered unexpected estrogen agonistic actions of TMS at high doses, including a paradoxical stimulation of breast ductal structures and the endometrium. These studies suggest that the enzyme inhibitory properties of TMS, as well as the effects on developing breast, could implicate a role for TMS in breast cancer prevention, but only in low doses and on developing breast

    A privacy-preserving solution for compressed storage and selective retrieval of genomic data

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    In clinical genomics, the continuous evolution of bioinformatic algorithms and sequencing platforms makes it beneficial to store patients' complete aligned genomic data in addition to variant calls relative to a reference sequence. Due to the large size of human genome sequence data files (varying from 30 GB to 200 GB depending on coverage), two major challenges facing genomics laboratories are the costs of storage and the efficiency of the initial data processing. In addition, privacy of genomic data is becoming an increasingly serious concern, yet no standard data storage solutions exist that enable compression, encryption, and selective retrieval. Here we present a privacy-preserving solution named SECRAM (Selective retrieval on Encrypted and Compressed Reference-oriented Alignment Map) for the secure storage of compressed aligned genomic data. Our solution enables selective retrieval of encrypted data and improves the efficiency of downstream analysis (e.g., variant calling). Compared withBAM, thede factostandard for storing aligned genomic data, SECRAM uses 18%less storage. Compared with CRAM, one of the most compressed nonencrypted formats (using 34% less storage than BAM), SECRAM maintains efficient compression and downstream data processing, while allowing for unprecedented levels of security in genomic data storage. Compared with previous work, the distinguishing features of SECRAM are that (1) it is position-based insteadofread-based,and(2)itallowsrandomqueryingofasubregionfromaBAM-likefileinanencryptedform.Ourmethod thus offers a space-saving, privacy-preserving, and effective solution for the storage of clinical genomic data. © 2016 Szalaj et al

    The bacterium Pseudomonas protegens antagonizes the microalga Chlamydomonas reinhardtii using a blend of toxins

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    The unicellular alga Chlamydomonas reinhardtii and the bacterium Pseudomonas protegens serve as a model to study the interactions between photosynthetic and heterotrophic microorganisms. P . protegens secretes the cyclic lipopeptide orfamide A that interferes with cytosolic Ca 2+ homeostasis in C . reinhardtii resulting in deflagellation of the algal cells. Here, we studied the roles of additional secondary metabolites secreted by P . protegens using individual compounds and co‐cultivation of algae with bacterial mutants. Rhizoxin S2, pyrrolnitrin, pyoluteorin, 2,4‐diacetylphloroglucinol (DAPG) and orfamide A all induce changes in cell morphology and inhibit the growth of C . reinhardtii . Rhizoxin S2 exerts the strongest growth inhibition, and its action depends on the spatial structure of the environment (agar versus liquid culture). Algal motility is unaffected by rhizoxin S2 and is most potently inhibited by orfamide A (IC 50 = 4.1 ÎŒM). Pyrrolnitrin and pyoluteorin both interfere with algal cytosolic Ca 2+ homeostasis and motility whereas high concentrations of DAPG immobilize C . reinhardtii without deflagellation or disturbance of Ca 2+ homeostasis. Co‐cultivation with a regulatory mutant of bacterial secondary metabolism (Δ gacA ) promotes algal growth under spatially structured conditions. Our results reveal how a single soil bacterium uses an arsenal of secreted antialgal compounds with complementary and partially overlapping activities

    Month of birth and child height in 40 countries

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    Lokshin and Radyakin (2012) present evidence that month of birth affects child physical growth in India. We replicate these correlations using the same data and demonstrate that they are the result of a spurious relationship between month of birth, age-at-measurement and child growth patterns in developing countries. We repeat the analysis on 39 additional countries and show that there is no evidence of seasonal birth effects in child height-for-age z-score in any country. Furthermore, we demonstrate that the Demographic and Health Survey data used to estimate the correlation is not suitable for the task due to a previously unrecognized source of measurement error in child month of birth. We document results from several papers that should be re-interpreted in light of this issue
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