101 research outputs found

    Sinkhole development in the Sivas gypsum karst, Turkey

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    The extensive gypsum karst of Sivas, Turkey is one of the most outstanding examples of bare gypsum karst in the world. It displays a number of remarkable geomorphic features, including: (1) two stepped planation surfaces cut-across folded gypsum developed during an initial phase of slow base level deepening punctuated by periods of stability; (2) unusual deeply entrenched gypsum canyons related to a subsequent phase of rapid fluvial incision and water table lowering; (3) a polygonal karst of superlative quality mainly developed in the upper surface; (4) relict valleys disrupted by sinkholes in the lower erosional surface; (5) a large number of bedrock collapse sinkholes mostly associated with the lower surface; and (6) numerous cover subsidence sinkholes developed in the valley floors. This work analyses the spatial distribution, characteristics and evolution of the sinkholes within the broad Plio-Quaternary geomorphological and paleohydrological evolution of the epigene karst system dominated by autogenic recharge. A cartographic sinkhole inventory has been produced in an area covering 2820 km(2) with morphometric data and including 295 bedrock collapse sinkholes and 302 cover subsidence sinkholes. The different sinkhole types show a general spatial zonation controlled by the hydrogeological functioning of the different sectors: (1) solution sinkholes (polygonal karst) in the upper recharge area; (2) bedrock collapse sinkholes in the lower denudation surface and close to the base level, where well developed caves are inferred; and (3) cover subsidence sinkholes, with high densities probably associated with areas of preferred groundwater discharge. The morphology of the bedrock collapse sinkholes, varying from small cylindrical holes to large and deep tronco-conical depressions with gentle slopes reflect to geomorphic evolution of these sinkholes that reach exceptionally large hectometre-scale diameters. Their evolution, involving substantial enlargement and deepening, is attributed to the solutional removal as solute load of large volumes of gypsum by downward vadose flow. This type of morphological evolution with significant post-collapse solutional denudation differs from that observed in carbonate rocks characterised by lower solubility and erodibility. The analysis of historical imagery reveals that bedrock collapse sinkholes currently have a very low probability of occurrence and that buried cover subsidence sinkholes are used for urban development creating risk situations. (C) 2021 The Author(s). Published by Elsevier B.V

    Antioxidants / Effects of -carotene and its cleavage products in primary pneumocyte type II cells

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    -Carotene has been shown to increase the risk of developing lung cancer in smokers and asbestos workers in two large scale trails, the Beta-Carotene and Retinol Efficacy Trial (CARET) and the Alpha-Tocopherol Beta-carotene Cancer Prevention Trial (ATBC). Based on this observation, it was proposed that genotoxic oxidative breakdown products may cause this effect. In support of this assumption, increased levels of sister chromatid exchanges, micronuclei, and chromosomal aberrations were found in primary hepatocyte cultures treated with a mixture of cleavage products (CPs) and the major product apo-8′carotenal. However, because these findings cannot directly be transferred to the lung due to the exceptional biotransformation capacity of the liver, potential genotoxic and cytotoxic effects of -carotene under oxidative stress and its CPs were investigated in primary pneumocyte type II cells. The results indicate that increased concentrations of -carotene in the presence of the redox cycling quinone dimethoxynaphthoquinone (DMNQ) exhibit a cytotoxic potential, as evidenced by an increase of apoptotic cells and loss of cell density at concentrations > 10 M. On the other hand, the analysis of micronucleated cells gave no clear picture due to the cytotoxicity related reduction of mitotic cells. Last, although CPs induced significant levels of DNA strand breaks even at concentrations 1 M and 5 M, respectively, -carotene in the presence of DMNQ did not cause DNA damage. Instead, -carotene appeared to act as an antioxidant. These findings are in contrast with what was demonstrated for primary hepatocytes and may reflect different sensitivities to and different metabolism of -carotene in the two cell types.(VLID)219514

    Inhalative Exposure to Vanadium Pentoxide Causes DNA Damage in Workers: Results of a Multiple End Point Study

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    BackgroundInhalative exposure to vanadium pentoxide (V(2)O(5)) causes lung cancer in rodents.ObjectiveThe aim of the study was to investigate the impact of V(2)O(5) on DNA stability in workers from a V(2)O(5) factory.MethodsWe determined DNA strand breaks in leukocytes of 52 workers and controls using the alkaline comet assay. We also investigated different parameters of chromosomal instability in lymphocytes of 23 workers and 24 controls using the cytokinesis-block micronucleus (MN) cytome method.ResultsSeven of eight biomarkers were increased in blood cells of the workers, and vanadium plasma concentrations in plasma were 7-fold higher than in the controls (0.31 microg/L). We observed no difference in DNA migration under standard conditions, but we found increased tail lengths due to formation of oxidized purines (7%) and pyrimidines (30%) with lesion-specific enzymes (formamidopyrimidine glycosylase and endonuclease III) in the workers. Bleomycin-induced DNA migration was higher in the exposed group (25%), whereas the repair of bleomycin-induced lesions was reduced. Workers had a 2.5-fold higher MN frequency, and nucleoplasmic bridges (NPBs) and nuclear buds (Nbuds) were increased 7-fold and 3-fold, respectively. Also, apoptosis and necrosis rates were higher, but only the latter parameter reached statistical significance.ConclusionsV(2)O(5) causes oxidation of DNA bases, affects DNA repair, and induces formation of MNs, NPBs, and Nbuds in blood cells, suggesting that the workers are at increased risk for cancer and other diseases that are related to DNA instability.Veronika A. Ehrlich, Armen K. Nersesyan, Kambis Atefie, Christine Hoelzl, Franziska Ferk, Julia Bichler, Eva Valic, Andreas Schaffer, Rolf Schulte‑Hermann, Michael Fenech, Karl‑Heinz Wagner and Siegfried Knasmüllerhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC2599764

    Role of Androgen Receptor CAG Repeat Polymorphism and X-Inactivation in the Manifestation of Recurrent Spontaneous Abortions in Indian Women

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    The aim of the present study was to investigate the role of CAG repeat polymorphism and X-chromosome Inactivation (XCI) pattern in Recurrent Spontaneous Abortions among Indian women which has not been hitherto explored. 117 RSA cases and 224 Controls were included in the study. Cases were recruited from two different hospitals - Lakshmi Fertility Clinic, Nellore and Fernandez Maternity Hospital, Hyderabad. Controls were roughly matched for age, ethnicity and socioeconomic status. The CAG repeats of the Androgen Receptor gene were genotyped using a PCR-based assay and were analysed using the GeneMapper software to determine the CAG repeat length. XCI analysis was also carried out to assess the inactivation percentages. RSA cases had a significantly greater frequency of allele sizes in the polymorphic range above 19 repeats (p = 0.006), which is the median value of the controls, and in the biallelic mean range above 21 repeats (p = 0.002). We found no evidence of abnormal incidence of skewed X-inactivation. We conclude that longer CAG repeat lengths are associated with increased odds for RSA with statistical power estimated to be ∼90%

    Genetic polymorphisms are associated with serum levels of sex hormone binding globulin in postmenopausal women

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    <p>Abstract</p> <p>Background</p> <p>Estrogen activity plays a critical role in bone homeostasis. The serum levels of sex hormone binding globulin (SHBG) influence free estrogen levels and activity on target tissues. The objective of this study was to analyze the influence of common polymorphisms of the <it>SHBG </it>gene on serum SHBG, bone mineral density (BMD), and osteoporotic fractures.</p> <p>Methods</p> <p>Four biallelic polymorphisms of the <it>SHBG </it>gene were studied by means of Taqman assays in 753 postmenopausal women. BMD was measured by DXA and serum SHBG was measured by ELISA.</p> <p>Results</p> <p>Age, body weight, and two polymorphisms of the <it>SHBG </it>gene (rs6257 and rs1799941 [A/G]) were significantly associated with serum SHBG in unadjusted and age- and weight-adjusted models. Alleles at the rs1799941 locus showed the strongest association with serum SHBG (p = 0.0004). The difference in SHBG levels between women with AA and GG genotypes at the rs1799941 locus was 39%. There were no significant differences in BMD across SHBG genotypes. The genotypes showed similar frequency distributions in control women and women with vertebral or hip fractures.</p> <p>Conclusion</p> <p>Some common genetic variants of the <it>SHBG </it>gene, and particularly an A/G polymorphism situated in the 5' region, influence serum SHBG levels. However, a significant association with BMD or osteoporotic fractures has not been demonstrated.</p

    Systems Biology in ELIXIR: modelling in the spotlight

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    In this white paper, we describe the founding of a new ELIXIR Community - the Systems Biology Community - and its proposed future contributions to both ELIXIR and the broader community of systems biologists in Europe and worldwide. The Community believes that the infrastructure aspects of systems biology - databases, (modelling) tools and standards development, as well as training and access to cloud infrastructure - are not only appropriate components of the ELIXIR infrastructure, but will prove key components of ELIXIR\u27s future support of advanced biological applications and personalised medicine. By way of a series of meetings, the Community identified seven key areas for its future activities, reflecting both future needs and previous and current activities within ELIXIR Platforms and Communities. These are: overcoming barriers to the wider uptake of systems biology; linking new and existing data to systems biology models; interoperability of systems biology resources; further development and embedding of systems medicine; provisioning of modelling as a service; building and coordinating capacity building and training resources; and supporting industrial embedding of systems biology. A set of objectives for the Community has been identified under four main headline areas: Standardisation and Interoperability, Technology, Capacity Building and Training, and Industrial Embedding. These are grouped into short-term (3-year), mid-term (6-year) and long-term (10-year) objectives

    Community-driven ELIXIR activities in single-cell omics

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    Single-cell omics (SCO) has revolutionized the way and the level of resolution by which life science research is conducted, not only impacting our understanding of fundamental cell biology but also providing novel solutions in cutting-edge medical research. The rapid development of single-cell technologies has been accompanied by the active development of data analysis methods, resulting in a plethora of new analysis tools and strategies every year. Such a rapid development of SCO methods and tools poses several challenges in standardization, benchmarking, computational resources and training. These challenges are in line with the activities of ELIXIR, the European coordinated infrastructure for life science data. Here, we describe the current landscape of and the main challenges in SCO data, and propose the creation of the ELIXIR SCO Community, to coordinate the efforts in order to best serve SCO researchers in Europe and beyond. The Community will build on top of national experiences and pave the way towards integrated long-term solutions for SCO research. Keywor

    Current Wildland Fire Patterns and Challenges in Europe : A Synthesis of National Perspectives

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    Changes in climate, land use, and land management impact the occurrence and severity of wildland fires in many parts of the world. This is particularly evident in Europe, where ongoing changes in land use have strongly modified fire patterns over the last decades. Although satellite data by the European Forest Fire Information System provide large-scale wildland fire statistics across European countries, there is still a crucial need to collect and summarize in-depth local analysis and understanding of the wildland fire condition and associated challenges across Europe. This article aims to provide a general overview of the current wildland fire patterns and challenges as perceived by national representatives, supplemented by national fire statistics (2009-2018) across Europe. For each of the 31 countries included, we present a perspective authored by scientists or practitioners from each respective country, representing a wide range of disciplines and cultural backgrounds. The authors were selected from members of the COST Action "Fire and the Earth System: Science & Society" funded by the European Commission with the aim to share knowledge and improve communication about wildland fire. Where relevant, a brief overview of key studies, particular wildland fire challenges a country is facing, and an overview of notable recent fire events are also presented. Key perceived challenges included (1) the lack of consistent and detailed records for wildland fire events, within and across countries, (2) an increase in wildland fires that pose a risk to properties and human life due to high population densities and sprawl into forested regions, and (3) the view that, irrespective of changes in management, climate change is likely to increase the frequency and impact of wildland fires in the coming decades. Addressing challenge (1) will not only be valuable in advancing national and pan-European wildland fire management strategies, but also in evaluating perceptions (2) and (3) against more robust quantitative evidence.Peer reviewe
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