62 research outputs found

    X-ray properties of the distant cluster Cl0016+16

    Get PDF
    We present X-ray data on the distant cluster Cl0016+16 (z=0.5545) from ROSAT PSPC and HRI observations and use them to study the physics of the intracluster medium (ICM) and the dynamical state of the cluster. The surface brightness distribution is not only described by a spherically symmetric model but also by a two-dimensional β\beta -model fit. Subtracting an elliptical model cluster as defined by the best fit parameters of the two-dimensional model we find significant residuals, indicating an additional, extended X-ray source within the cluster. This source, likely to be a merging subcomponent of the cluster, coincides with a peak in the weak lensing mass map of Smail et. al. (1995). In the course of this analysis we present a new approach to quantify the significance of substructure in cluster X-ray images dominated by Poisson noise and smoothed with a Gauss filter. We determine the radial mass profile integrated out to a radius of 3Mpc and find for the total mass of the cluster a value of ∼1.4−3.3×1015\sim 1.4-3.3 \times 10^{15} \msun and ∼4.5×1014\sim 4.5 \times 10^{14} \msun for the gas mass, yielding a gas-to-total mass ratio of 14-32\%. There is no significant radial dependence of the gas-to-total mass ratio in the cluster.Comment: 11 pages, submitted to MNRA

    Abell 3627: A Nearby, X-ray Bright, and Massive Galaxy Cluster

    Full text link
    The cluster A3627 was recently recognized to be a very massive, nearby cluster in a galaxy survey close to the galactic plane. We are reporting on ROSAT PSPC observations of this object which confirm that the cluster is indeed very massive. The X-ray emission detected from the cluster extends over almost 1 degree in radius. The X-ray image is not spherically symmetric and shows indications of an ongoing cluster merger. Due to the strong interstellar absorption the spectral analysis and the gas temperature determination are difficult. The data are consistent with an overall gas temperature in the range 5 to 10 keV. There are signs of temperature variations in the merger region. A mass estimate based on the X-ray data yields values of 0.4−2.2⋅10150.4 - 2.2 \cdot 10^{15} \msu \ if extrapolated to the virial radius of 3h50−13 h_{50}^{-1} Mpc. In the ROSAT energy band (0.1 - 2.4 keV) the cluster emission yields a flux of about 2⋅10−102 \cdot 10^{-10} erg s−1^{-1} cm−2^{-2} which makes A3627 the 6th^{th} brightest cluster in the ROSAT All Sky Survey. The cluster was missed in earlier X-ray surveys because it was confused with a neighbouring X-ray bright, galactic X-ray binary (1H1556-605). The large X-ray flux makes A3627 an important target for future studies.Comment: 14 pages, Latex file, including aaspp.sty, 9 postscript figures and 1 table, accepted for publication by the Astrophysical Journa

    Structuring osteosarcoma knowledge: an osteosarcoma-gene association database based on literature mining and manual annotation

    Full text link
    Osteosarcoma (OS) is the most common primary bone cancer exhibiting high genomic instability. This genomic instability affects multiple genes and microRNAs to a varying extent depending on patient and tumor subtype. Massive research is ongoing to identify genes including their gene products and microRNAs that correlate with disease progression and might be used as biomarkers for OS. However, the genomic complexity hampers the identification of reliable biomarkers. Up to now, clinico-pathological factors are the key determinants to guide prognosis and therapeutic treatments. Each day, new studies about OS are published and complicate the acquisition of information to support biomarker discovery and therapeutic improvements. Thus, it is necessary to provide a structured and annotated view on the current OS knowledge that is quick and easily accessible to researchers of the field. Therefore, we developed a publicly available database and Web interface that serves as resource for OS-associated genes and microRNAs. Genes and microRNAs were collected using an automated dictionary-based gene recognition procedure followed by manual review and annotation by experts of the field. In total, 911 genes and 81 microRNAs related to 1331 PubMed abstracts were collected (last update: 29 October 2013). Users can evaluate genes and microRNAs according to their potential prognostic and therapeutic impact, the experimental procedures, the sample types, the biological contexts and microRNA target gene interactions. Additionally, a pathway enrichment analysis of the collected genes highlights different aspects of OS progression. OS requires pathways commonly deregulated in cancer but also features OS-specific alterations like deregulated osteoclast differentiation. To our knowledge, this is the first effort of an OS database containing manual reviewed and annotated up-to-date OS knowledge. It might be a useful resource especially for the bone tumor research community, as specific information about genes or microRNAs is quick and easily accessible. Hence, this platform can support the ongoing OS research and biomarker discovery

    Gene Constellation of Influenza A Virus Reassortants with High Growth Phenotype Prepared as Seed Candidates for Vaccine Production

    Get PDF
    BACKGROUND: Influenza A virus vaccines undergo yearly reformulations due to the antigenic variability of the virus caused by antigenic drift and shift. It is critical to the vaccine manufacturing process to obtain influenza A seed virus that is antigenically identical to circulating wild type (wt) virus and grows to high titers in embryonated chicken eggs. Inactivated influenza A seasonal vaccines are generated by classical reassortment. The classical method takes advantage of the ability of the influenza virus to reassort based on the segmented nature of its genome. In ovo co-inoculation of a high growth or yield (hy) donor virus and a low yield wt virus with antibody selection against the donor surface antigens results in progeny viruses that grow to high titers in ovo with wt origin hemagglutinin (HA) and neuraminidase (NA) glycoproteins. In this report we determined the parental origin of the remaining six genes encoding the internal proteins that contribute to the hy phenotype in ovo. METHODOLOGY: The genetic analysis was conducted using reverse transcription-polymerase chain reaction (RT-PCR) and restriction fragment length polymorphism (RFLP). The characterization was conducted to determine the parental origin of the gene segments (hy donor virus or wt virus), gene segment ratios and constellations. Fold increase in growth of reassortant viruses compared to respective parent wt viruses was determined by hemagglutination assay titers. SIGNIFICANCE: In this study fifty-seven influenza A vaccine candidate reassortants were analyzed for the presence or absence of correlations between specific gene segment ratios, gene constellations and hy reassortant phenotype. We found two gene ratios, 6:2 and 5:3, to be the most prevalent among the hy reassortants analyzed, although other gene ratios also conferred hy in certain reassortants

    CRF-R1 activation in the anterior-dorsal BNST induces maternal neglect in lactating rats via an HPA axis-independent central mechanism

    Get PDF
    AbstractAdequate maternal behavior in rats requires minimal corticotropin-releasing factor receptor (CRF-R) activation in the medial-posterior bed nucleus of the stria terminalis (mpBNST). Based on the architectural heterogeneity of the BNST and its distinct inter-neural connectivity, we tested whether CRF-R manipulation in another functional part, the anterior-dorsal BNST (adBNST), differentially modulates maternal behavior.We demonstrate that in the adBNST, activation of CRF-R1 reduced arched back nursing (ABN) and nursing, whereas activation of CRF-R2 resulted in an initial reduction in nursing but significantly increased the incidence of ABN 5h after the treatment. Following stressor exposure, which is detrimental to maternal care, ABN tended to be protected by CRF-R1 blockade. Maternal motivation, maternal aggression, and anxiety were unaffected by any manipulation. Furthermore, under basal and stress conditions, activation of adBNST CRF-R1 increased plasma ACTH and corticosterone concentrations, whereas stimulation of adBNST CRF-R2 increased basal plasma ACTH and corticosterone concentrations, but blocked the stress-induced increase in plasma corticosterone secretion. Moreover, both the CRF-R1 and -R2 antagonists prevented the stress-induced increase in plasma corticosterone secretion. Importantly, elevated levels of circulating corticosterone induced by intra-adBNST administration of CRF-R1 or -R2 agonist did not impact maternal care. Finally, Crf mRNA expression in the adBNST was increased during lactation; however, Crfr1 mRNA expression was similar between lactating and virgin rats.In conclusion, maternal care is impaired by adBNST CRF-R1 activation, and this appears to be the result of a central action, rather than an effect of elevated circulating levels of CORT. These data provide new insights into potential causes of disturbed maternal behavior postpartum

    Towards crystal structure prediction of complex organic compounds - a report on the fifth blind test

    Get PDF
    Following on from the success of the previous crystal structure prediction blind tests (CSP1999, CSP2001, CSP2004 and CSP2007), a fifth such collaborative project (CSP2010) was organized at the Cambridge Crystallographic Data Centre. A range of methodologies was used by the participating groups in order to evaluate the ability of the current computational methods to predict the crystal structures of the six organic molecules chosen as targets for this blind test. The first four targets, two rigid molecules, one semi-flexible molecule and a 1: 1 salt, matched the criteria for the targets from CSP2007, while the last two targets belonged to two new challenging categories - a larger, much more flexible molecule and a hydrate with more than one polymorph. Each group submitted three predictions for each target it attempted. There was at least one successful prediction for each target, and two groups were able to successfully predict the structure of the large flexible molecule as their first place submission. The results show that while not as many groups successfully predicted the structures of the three smallest molecules as in CSP2007, there is now evidence that methodologies such as dispersion-corrected density functional theory (DFT-D) are able to reliably do so. The results also highlight the many challenges posed by more complex systems and show that there are still issues to be overcome

    Recommendations for Addressing Priority Io Science in the Next Decade

    Get PDF
    Io is a priority destination for solar system exploration. The scope and importance of science questions at Io necessitates a broad portfolio of research and analysis, telescopic observations, and planetary missions - including a dedicated New Frontiers class Io mission
    • …
    corecore