499 research outputs found

    Measuring the Hidden Aspects of Solar Magnetism

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    2008 marks the 100th anniversary of the discovery of astrophysical magnetic fields, when George Ellery Hale recorded the Zeeman splitting of spectral lines in sunspots. With the introduction of Babcock's photoelectric magnetograph it soon became clear that the Sun's magnetic field outside sunspots is extremely structured. The field strengths that were measured were found to get larger when the spatial resolution was improved. It was therefore necessary to come up with methods to go beyond the spatial resolution limit and diagnose the intrinsic magnetic-field properties without dependence on the quality of the telescope used. The line-ratio technique that was developed in the early 1970s revealed a picture where most flux that we see in magnetograms originates in highly bundled, kG fields with a tiny volume filling factor. This led to interpretations in terms of discrete, strong-field magnetic flux tubes embedded in a rather field-free medium, and a whole industry of flux tube models at increasing levels of sophistication. This magnetic-field paradigm has now been shattered with the advent of high-precision imaging polarimeters that allow us to apply the so-called "Second Solar Spectrum" to diagnose aspects of solar magnetism that have been hidden to Zeeman diagnostics. It is found that the bulk of the photospheric volume is seething with intermediately strong, tangled fields. In the new paradigm the field behaves like a fractal with a high degree of self-similarity, spanning about 8 orders of magnitude in scale size, down to scales of order 10 m.Comment: To appear in "Magnetic Coupling between the Interior and the Atmosphere of the Sun", eds. S.S. Hasan and R.J. Rutten, Astrophysics and Space Science Proceedings, Springer-Verlag, Heidelberg, Berlin, 200

    A prevalent mutation with founder effect in Spanish Recessive Dystrophic Epidermolysis Bullosa families

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    <p>Abstract</p> <p>Background</p> <p>Recessive Dystrophic Epidermolysis Bullosa (RDEB) is a genodermatosis caused by more than 500 different mutations in the <it>COL7A1 </it>gene and characterized by blistering of the skin following a minimal friction or mechanical trauma.</p> <p>The identification of a cluster of RDEB pedigrees carrying the c.6527insC mutation in a specific area raises the question of the origin of this mutation from a common ancestor or as a result of a hotspot mutation. The aim of this study was to investigate the origin of the c.6527insC mutation.</p> <p>Methods</p> <p>Haplotypes were constructed by genotyping nine single nucleotides polymorphisms (SNPs) throughout the <it>COL7A1 </it>gene. Haplotypes were determined in RDEB patients and control samples, both of Spanish origin.</p> <p>Results</p> <p>Sixteen different haplotypes were identified in our study. A single haplotype cosegregated with the c.6527insC mutation.</p> <p>Conclusion</p> <p>Haplotype analysis showed that all alleles carrying the c.6527insC mutation shared the same haplotype cosegregating with this mutation (<b><it>CCGCTCAAA_6527insC</it></b>), thus suggesting the presence of a common ancestor.</p

    Copy number architectures define treatment-mediated selection of lethal prostate cancer clones

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    Despite initial responses to hormone treatment, metastatic prostate cancer invariably evolves to a lethal state. To characterize the intra-patient evolutionary relationships of metastases that evade treatment, we perform genome-wide copy number profiling and bespoke approaches targeting the androgen receptor (AR) on 167 metastatic regions from 11 organs harvested post-mortem from 10 men who died from prostate cancer. We identify diverse and patient-unique alterations clustering around the AR in metastases from every patient with evidence of independent acquisition of related genomic changes within an individual and, in some patients, the co-existence of AR-neutral clones. Using the genomic boundaries of pan-autosome copy number changes, we confirm a common clone of origin across metastases and diagnostic biopsies, and identified in individual patients, clusters of metastases occupied by dominant clones with diverged autosomal copy number alterations. These autosome-defined clusters are characterized by cluster-specific AR gene architectures, and in two index cases are topologically more congruent than by chance (p-values 3.07 × 10-8 and 6.4 × 10-4). Integration with anatomical sites suggests patterns of spread and points of genomic divergence. Here, we show that copy number boundaries identify treatment-selected clones with putatively distinct lethal trajectories

    The Main Belt Comets and ice in the Solar System

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    We review the evidence for buried ice in the asteroid belt; specifically the questions around the so-called Main Belt Comets (MBCs). We summarise the evidence for water throughout the Solar System, and describe the various methods for detecting it, including remote sensing from ultraviolet to radio wavelengths. We review progress in the first decade of study of MBCs, including observations, modelling of ice survival, and discussion on their origins. We then look at which methods will likely be most effective for further progress, including the key challenge of direct detection of (escaping) water in these bodies

    A quantum-chemical study of the binding ability of βXaaHisGlyHis towards copper(II) ion

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    The present study analyzed binding of Cu2+ to tetrapeptides in water solution at several levels of theoretical approximation. The methods used to study the energetic and structural properties of the complexes in question include semiempirical hamiltonians, density functional theory as well as ab initio approaches including electron correlation effects. In order to shed light on the character of interactions between Cu2+ and peptides, which are expected to be mainly electrostatic in nature, decomposition of interaction energy into physically meaningful components was applied

    A review of elliptical and disc galaxy structure, and modern scaling laws

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    A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their models to describe the radial distribution of stars in `nebulae'. This article reviews the progress since then, providing both an historical perspective and a contemporary review of the stellar structure of bulges, discs and elliptical galaxies. The quantification of galaxy nuclei, such as central mass deficits and excess nuclear light, plus the structure of dark matter halos and cD galaxy envelopes, are discussed. Issues pertaining to spiral galaxies including dust, bulge-to-disc ratios, bulgeless galaxies, bars and the identification of pseudobulges are also reviewed. An array of modern scaling relations involving sizes, luminosities, surface brightnesses and stellar concentrations are presented, many of which are shown to be curved. These 'redshift zero' relations not only quantify the behavior and nature of galaxies in the Universe today, but are the modern benchmark for evolutionary studies of galaxies, whether based on observations, N-body-simulations or semi-analytical modelling. For example, it is shown that some of the recently discovered compact elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to appear in "Planets, Stars and Stellar Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references incl. many somewhat forgotten, pioneer papers. Original submission to Springer: 07-June-201

    Anthrax Toxins Induce Shock in Rats by Depressed Cardiac Ventricular Function

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    Anthrax infections are frequently associated with severe and often irreversible hypotensive shock. The isolated toxic proteins of Bacillus anthracis produce a non-cytokine-mediated hypotension in rats by unknown mechanisms. These observations suggest the anthrax toxins have direct cardiovascular effects. Here, we characterize these effects. As a first step, we administered systemically anthrax lethal toxin (LeTx) and edema toxin (EdTx) to cohorts of three to twelve rats at different doses and determined the time of onset, degree of hypotension and mortality. We measured serum concentrations of the protective antigen (PA) toxin component at various time points after infusion. Peak serum levels of PA were in the µg/mL range with half-lives of 10–20 minutes. With doses that produced hypotension with delayed lethality, we then gave bolus intravenous infusions of toxins to groups of four to six instrumented rats and continuously monitored blood pressure by telemetry. Finally, the same doses used in the telemetry experiments were given to additional groups of four rats, and echocardiography was performed pretreatment and one, two, three and twenty-four hours post-treatment. LeTx and EdTx each produced hypotension. We observed a doubling of the velocity of propagation and 20% increases in left ventricular diastolic and systolic areas in LeTx-treated rats, but not in EdTx-treated rats. EdTx-but not LeTx-treated rats showed a significant increase in heart rate. These results indicate that LeTx reduced left ventricular systolic function and EdTx reduced preload. Uptake of toxins occurs readily into tissues with biological effects occurring within minutes to hours of serum toxin concentrations in the µg/mL range. LeTx and EdTx yield an irreversible shock with subsequent death. These findings should provide a basis for the rational design of drug interventions to reduce the dismal prognosis of systemic anthrax infections

    Macro-financial linkages and bank behaviour: evidence from the second-round effects of the global financial crisis on East Asia

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    This paper studies the link between macro-financial variability and bank behaviour, which justifies the second-round effects of the global financial crisis on East Asia. Following Gallego et al. (The impact of the global economic and financial crisis on Central Eastern and South Eastern Europe (CESEE) and Latin America, 2010), the second round effects are defined as the adverse feedback loop from the slumps in economic activities and sharp financial market deterioration, which may influence the financial performance of bank, inter alia via deteriorating credit quality, declining profitability and increasing problems in retaining necessary capitalization. Differentiating itself from other research, this study stresses adjustments in four dimensions of bank performance and behaviour: asset quality, profitability, capital adequacy, and lending behaviour, assuming that any change in a bank-specific characteristic is induced by endogenous adjustments of the others. The empirical results based on partial adjustment models and two-step system GMM estimation show that bank’s adjustment behaviour is subject to the variation in the macro-financial environment and the stress condition in the global financial market. There is no convincing evidence to support the effectiveness of policy rate cut to boots bank lending and to avoid a financial accelerator effect

    Characterising the KMP-11 and HSP-70 recombinant antigens' humoral immune response profile in chagasic patients

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    11 pages, 6 figures.-- The pre-publication history for this paper can be accessed here: http://www.biomedcentral.com/1471-2334/9/186/pre pubBackground: Antigen specificity and IgG subclass could be significant in the natural history of Chagas' disease. The relationship between the different stages of human Chagas' disease and the profiles of total IgG and its subclasses were thus analysed here; they were directed against a crude T. cruzi extract and three recombinant antigens: the T. cruzi kinetoplastid membrane protein-11 (rKMP-11), an internal fragment of the T. cruzi HSP-70 protein192-433, and the entire Trypanosoma rangeli HSP-70 protein. Methods: Seventeen Brazilian acute chagasic patients, 50 Colombian chronic chagasic patients (21 indeterminate and 29 cardiopathic patients) and 30 healthy individuals were included. Total IgG and its subtypes directed against the above-mentioned recombinant antigens were determined by ELISA tests. Results: The T. cruzi KMP-11 and T. rangeli HSP-70 recombinant proteins were able to distinguish both acute from chronic chagasic patients and infected people from healthy individuals. Specific antibodies to T. cruzi crude antigen in acute patients came from IgG3 and IgG4 subclasses whereas IgG1 and IgG3 were the prevalent isotypes in indeterminate and chronic chagasic patients. By contrast, the specific prominent antibodies in all disease stages against T. cruzi KMP-11 and T. rangeli HSP-70 recombinant antigens were the IgG1 subclass.This work was supported by Colciencias Research project No. 1203-333- 18692. IDF was supported by Colciencias and the Universidad Javeriana's Young Researcher 2008 Programme (Bogotá, Colombia). MCT and MCL were supported by P06-CTS-02242 Grant from PAI (Junta de Andalucia) and RICET-RD06/0021-0014, Spain. MS received financial support from the Brazilian agency - CNPq.Peer reviewe

    Characterization of the behavior of carotenoids from pitanga (Eugenia uniflora) and buriti (Mauritia flexuosa) during microemulsion production and in a dynamic gastrointestinal system

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    Uncommon tropical fruits are emerging as raw-material for new food products with health benefits. This work aimed at formulating and processing microemulsions from pitanga (Eugenia uniflora) and buriti (Mauritia flexuosa) fruits, since they are very rich in carotenoids (particularly lycopene and -carotene), in order to encapsulate and increase carotenoids bioaccessibility. Pitanga and buriti microemulsions were produced by applying a direct processing (high-speed homogenization at 15,000 rpm and ultrasound with 20 kHz probe at 40% amplitude) of the whole pulp together with surfactant (Tween 80 or Whey Protein Isolate at 2%) and corn oil (5%). All treatments (HSHUS for 04, 40, 44, 48 minmin) applied were able to increase the amount of carotenoid released. However, the processing also decreased the total amount of carotenoids in the whole pulp of studied fruits. The impact of processing during microemulsion production was not severe. The overall data suggest that the presence of surfactant and oil during processing may protect the carotenoids in fruits and microemulsions. Final recovery of total carotenoids, after passing the samples through a dynamic gastrointestinal system that simulates the human digestion, was higher for microemulsions than for whole pulps. High losses of total carotenoids in buriti and -carotene and lycopene in pitanga occurred during jejunum and ileum phases. The present work confirms that it is possible to increase -carotene and lycopene bioaccessibility from fruits by directly processing microemulsions (p<0.01).This work was supported by the São Paulo Research Foundation—FAPESP through research funding [Grant #2015/15507-9] and Ph.D. scholarship for Paulo Berni [Grant #2014/15119-6] and a Research Internships Abroad (BEPE) support [Grant #2016/13355-0]. The author Ana C. Pinheiro is recipient of a fellowship from the Portuguese Foundation for Science and Technology (FCT) [Grant SFRH/BPD/101181/2014]info:eu-repo/semantics/publishedVersio
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