549 research outputs found

    IUPACpal: efficient identification of inverted repeats in IUPAC-encoded DNA sequences

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    Background: An inverted repeat is a DNA sequence followed downstream by its reverse complement, potentially with a gap in the centre. Inverted repeats are found in both prokaryotic and eukaryotic genomes and they have been linked with countless possible functions. Many international consortia provide a comprehensive description of common genetic variation making alternative sequence representations, such as IUPAC encoding, necessary for leveraging the full potential of such broad variation datasets. Results: We present IUPACpal, an exact tool for efficient identification of inverted repeats in IUPAC-encoded DNA sequences allowing also for potential mismatches and gaps in the inverted repeats. Conclusion: Within the parameters that were tested, our experimental results show that IUPACpal compares favourably to a similar application packaged with EMBOSS. We show that IUPACpal identifies many previously unidentified inverted repeats when compared with EMBOSS, and that this is also performed with orders of magnitude improved speed.</p

    DRhoGEF2 Regulates Cellular Tension and Cell Pulsations in the Amnioserosa during Drosophila Dorsal Closure

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    Coordination of apical constriction in epithelial sheets is a fundamental process during embryogenesis. Here, we show that DRhoGEF2 is a key regulator of apical pulsation and constriction of amnioserosal cells during Drosophila dorsal closure. Amnioserosal cells mutant for DRhoGEF2 exhibit a consistent decrease in amnioserosa pulsations whereas overexpression of DRhoGEF2 in this tissue leads to an increase in the contraction time of pulsations. We probed the physical properties of the amnioserosa to show that the average tension in DRhoGEF2 mutant cells is lower than wild-type and that overexpression of DRhoGEF2 results in a tissue that is more solid-like than wild-type. We also observe that in the DRhoGEF2 overexpressing cells there is a dramatic increase of apical actomyosin coalescence that can contribute to the generation of more contractile forces, leading to amnioserosal cells with smaller apical surface than wild-type. Conversely, in DRhoGEF2 mutants, the apical actomyosin coalescence is impaired. These results identify DRhoGEF2 as an upstream regulator of the actomyosin contractile machinery that drives amnioserosa cells pulsations and apical constriction

    FTO gene variation and measures of body mass in an African population

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    BACKGROUND: Variation in the fat mass and obesity associated (FTO) gene has been reproducibly associated with body mass index (BMI) and obesity in populations of White European origin. Data from Asians and African-Americans is less conclusive. METHODS: We assessed the effect of 16 FTO polymorphisms on body mass in a large population of predominantly lean Gambians (N(max) 2208) participating in a long-term surveillance program providing contemporary and early-life anthropometric measurements. RESULTS: Sixteen FTO tagSNPs screened here, including several associated with BMI in Europeans, were not associated with birth weight (BWT), early weight gain in 1-2 year olds, BMI in adults (> or = 18 y), or weight-for-height (WFH) z-score across all ages. No association was seen between genotype and WFH z-score or other measures of body mass. The confidence limits indicate that the effect size for WFH z-score never exceeded 0.17 units per allele copy for any SNP (excluding the three SNPs with allele < 15%). with much the lowest allele frequency. The confidence interval of the effect size for rs9939609 did not overlap that reported previously in Europeans. CONCLUSION: To our knowledge this is the first study of FTO gene variation in a well-characterised African population. Our results suggest that FTO gene variation does not influence measures of body mass in Gambians living a traditional lifestyle, or has a smaller effect than that detected in Europeans. These findings are not directly comparable to results from previous studies in African-Americans due to differences in study design and analysis. It is also possible that any effect of FTO genotype on body mass is of limited relevance in a lean population where little excess food is available, compared to similar ethnic populations where food supply is plentiful

    Pressure is not a state function for generic active fluids

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    Pressure is the mechanical force per unit area that a confined system exerts on its container. In thermal equilibrium, it depends only on bulk properties (density, temperature, etc.) through an equation of state. Here we show that in a wide class of active systems the pressure depends on the precise interactions between the active particles and the confining walls. In general, therefore, active fluids have no equation of state, their mechanical pressures exhibit anomalous properties that defy the familiar thermodynamic reasoning that holds in equilibrium. The pressure remains a function of state, however, in some specific and well-studied active models that tacitly restrict the character of the particle-wall and/or particle-particle interactions.Comment: 8 pages + 9 SI pages, Nature Physics (2015

    Development of paediatric quality of inpatient care indicators for low-income countries - A Delphi study

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    BACKGROUND: Indicators of quality of care for children in hospitals in low-income countries have been proposed, but information on their perceived validity and acceptability is lacking. METHODS: Potential indicators representing structural and process aspects of care for six common conditions were selected from existing, largely qualitative WHO assessment tools and guidelines. We employed the Delphi technique, which combines expert opinion and existing scientific information, to assess their perceived validity and acceptability. Panels of experts, one representing an international panel and one a national (Kenyan) panel, were asked to rate the indicators over 3 rounds and 2 rounds respectively according to a variety of attributes. RESULTS: Based on a pre-specified consensus criteria most of the indicators presented to the experts were accepted: 112/137(82%) and 94/133(71%) for the international and local panels respectively. For the other indicators there was no consensus; none were rejected. Most indicators were rated highly on link to outcomes, reliability, relevance, actionability and priority but rated more poorly on feasibility of data collection under routine conditions. There was moderate to substantial agreement between the two panels of experts. CONCLUSIONS: This Delphi study provided evidence for the perceived usefulness of most of a set of measures of quality of hospital care for children proposed for use in low-income countries. However, both international and local experts expressed concerns that data for many process-based indicators may not currently be available. The feasibility of widespread quality assessment and responsiveness of indicators to intervention should be examined as part of continued efforts to improve approaches to informative hospital quality assessment

    Application of new methods of environment analysis and assessment in landscape audits : case studies of urban areas like Czestochowa, Poland

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    Following the 2000 European Landscape Convention, a new act strengthening landscape protection instruments has been in force since 2015. It sets forth legal aspects of landscape shaping (Dziennik Ustaw 2015, poz. 774) and introduces landscape audits at the province level. A landscape audit consists in identification and characterization of selected landscapes, assessment of their value, selection of so-called priority landscapes and identification of threats for preservation of their value. An audit complies with GIS standards. Analyses use source materials, i.e. digital maps of physical-geographical mesoregions, current topographic maps of digital resources of cartographic databases, latest orthophotomaps and DTMs, maps of potential vegetation, geobotanic regionalization, historic-cultural regionalization and natural landscape types, documentation of historical and cultural values and related complementary resources. A special new methodology (Solon et al. 2014), developed for auditing, was tested in 2015 in an urban area (Myga-Piatek et al. 2015). Landscapes are characterized by determining their analytic (natural and cultural) and synthetic features, with particular focus on the stage of delimitation and identification of landscape units in urban areas. Czestochowa was selected as a case study due to its large natural (karst landscapes of the Czestochowa Upland, numerous forests, nature reserves) and cultural (Saint Mary’s Sanctuary, unique urban architecture) potential. Czestochowa is also a city of former iron ore and mineral resources exploitation, still active industry, dynamic urban sprawl within former farming areas, and dynamically growing tourism. Landscape delimitation and identification distinguished 75 landscape units basing on uniform landscape background (uniform cover and use of the land). Landscape assessment used a new assessment method for anthropogenic transformation of landscape – the indicator describing the correlation between the mean shape index (MSI) and the Shannon diversity index (SHDI) (Pukowiec-Kurda, Sobala 2016). Particular threats and planning suggestions, useful in development of urban areas, were presented for selected priority landscapes
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