3,605 research outputs found

    X-ray observations of the galaxy cluster PKS 0745-191: To the virial radius, and beyond

    Full text link
    We measure X-ray emission from the outskirts of the cluster of galaxies PKS 0745-191 with Suzaku, determining radial profiles of density, temperature, entropy, gas fraction, and mass. These measurements extend beyond the virial radius for the first time, providing new information about cluster assembly and the diffuse intracluster medium out to ~1.5 r_200, (r_200 ~ 1.7 Mpc ~ 15'). The temperature is found to decrease by roughly 70 per cent from 0.3-1 r_200. We also see a flattening of the entropy profile near the virial radius and consider the implications this has for the assumption of hydrostatic equilibrium when deriving mass estimates. We place these observations in the context of simulations and analytical models to develop a better understanding of non-gravitational physics in the outskirts of the cluster.Comment: 10 pages, 11 figures, accepted to MNRAS; expanded discussion of analysis and uncertainties, results qualitatively unchange

    Three-dimensional Binary Superlattices of Oppositely-charged Colloids

    Full text link
    We report the equilibrium self-assembly of binary crystals of oppositely-charged colloidal microspheres at high density. By varying the magnitude of the charge on near equal-sized spheres we show that the structure of the binary crystal may be switched between face-centered cubic, cesium chloride and sodium chloride. We interpret these transformations in terms of a competition between entropic and Coulombic forces

    Inferring the age and sex of ancient potters from fingerprint ridge densities: A data-driven, Bayesian mixture modelling approach

    Get PDF
    The density of epidermal ridges in a fingerprint varies predictably by age and sex. Archaeologists are therefore interested in using recovered fingerprints to learn about the ancient people who produced them. Recent studies focus on estimating the age and sex of individuals by measuring their fingerprints with one of two similar metrics: mean ridge breadth (MRB) or ridge density (RD). Yet these attempts face several critical problems: expected values for adult females and adolescent males are inherently indistinguishable, and inter-assemblage variation caused by biological and technological differences cannot be easily estimated. Each of these factors greatly decreases the accuracy of predictions based on individual prints, and together they condemn this strategy to relative uselessness. However, information in fingerprints from across an assemblage can be pooled to generate a more accurate depiction of potter demographics. We present a new approach to epidermal ridge density analysis using Bayesian mixture models with the following key benefits: Age and sex are estimated more accurately than existing methods by incorporating a data-driven understanding of how demographics and ridge density covary. Uncertainty in demographic estimates is automatically quantified and included in output. The Bayesian framework can be easily adapted to fit the unique needs of different researchers. </p

    Importance of osteoprotegrin and receptor activator of nuclear factor kB in breast cancer response to hepatocyte growth factor and the bone microenvironment in vitro

    Get PDF
    Osteoprotegrin (OPG), receptor activator of nuclear factor κB (RANK) and RANK ligand (RANKL) are signal transducers which have pleiotropic actions. Each tumour necrosis factor receptor superfamily member has unique structural attributes which directly couples them to signalling pathways involved in cell proliferation, differentiation and survival. Previous studies have clinically linked OPG, RANK and RANKL to increasing tumour burden, metastatic bone involvement and estrogen status. This study aimed to establish the potential implications of targeting endogenously produced OPG and RANK in the osteotropic breast cancer cell line MDA-MB‑231 in vitro. Subsequently this study also aimed to explore the potential links between these molecules with regards to hepatocyte growth factor (HGF) signalling and extracted bone proteins (BME). OPG and RANK expression was successfully suppressed using hammerhead ribozyme technology. Subsequently effects were explored in MDA-MB‑231 cell proliferation, matrix adhesion, migration and invasion in vitro function assays. Reduced OPG expression resulted in increased breast cancer cell migration and invasion. These increases, particularly invasion, appeared to however be reduced under the influence of the exogenous stimuli (HGF and BME). In contrast, suppression of RANK in MDA-MB‑231 breast cancer cells resulted in decreased cancer cell proliferation, matrix-adhesion, motility and invasion with little cumulative effect being noted after the addition of exogenous stimuli. The complexity of the bone environment underpins the vast number of soluble factors and signalling pathways which can influence osteotropic cancer behaviour and progression. Further work into elucidating all the pathways affected could potentially lead to better identification of those patients most at risk

    IL-17B Can Impact on Endothelial Cellular Traits Linked to Tumour Angiogenesis

    Get PDF
    IL-17B is a member of the IL-17 cytokine family which have been implicated in inflammatory response and autoimmune diseases such as rheumatoid arthritis. The founding member of this family, IL-17 (or IL-17A), has also been implicated in promoting tumour angiogenesis through the induction of other proangiogenic factors. Here we examine the potential of recombinant human IL-17B to contribute to the angiogenic process. In vitro rhIL-17B was able to inhibit HECV endothelial cell-matrix adhesion and cellular migration and also, at higher concentrations, could substantially reduce tubule formation compared to untreated HECV cells in a Matrigel tubule formation assay. This data suggests that IL-17B may act in an antiangiogenic manner

    Potential implication of Paxillin in cancer establishment within the bone environment

    Get PDF
    Background: Bone metastases are a common feature of advanced prostatic malignancies. They are characterised by a unique prevalence of osteoblastic phenotype and a poor prognosis. Paxillin is a 68-kDa signal transduction adaptor and scaffold protein that contains motifs involved in the mediation of protein–protein interactions. The state of paxillin phosphorylation is central to determining a cell's ability to adhere, detach and migrate and hence has been linked to processes such as wound repair and tumour metastasis. The current study explored the impact of paxillin suppression on prostate and breast cancer cell function and their responsiveness to hepatocyte growth factor (HGF) and bone matrix extract (BME) in order to assess its potential to influence bone colonization and homing. Materials and Methods: Hammerhead ribozyme transgenes were used to knockdown the expression of paxillin in breast and prostate cancer cell lines. The impact on the cell growth, migration, adhesion and invasion was assessed using in vitro functional assays. In order to explore potential mechanisms, focal adhesion kinase (FAK) inhibitor was also used. Results: Knockdown of paxillin expression was observed in all tested cell lines following transfection with the ribozyme transgene. The knockdown of paxillin increased proliferation and invasiveness of LNCaP cells, with no effect on their attachment abilities. The opposite, however, is true for PC-3 cells where, following knockdown, cellular attachment was significantly reduced, while no significant changes in growth and invasiveness were detected. In the MDA-MB-231 breast cancer knockdown model, cells had little difference in proliferative rates and generally increased attachment and reduced invasive abilities. Treatments with HGF and BME had differential effects on targeted cells when compared to controls. Conclusion: These data suggest that paxillin appears to influence major cell functions in a diverse range of prostate and breast cancer models. The responsiveness of cells to environmental factors such as HGF or BME may be influenced by paxillin status, although this seems to be dependent on cell type

    Mechanization of a High Aspect Ratio Wing for Aerodynamic Control

    Full text link
    Investigations are conducted to mechanize a controlled spanwise-varying airfoil camber change for a high aspect ratio wing, resulting in optimized aerodynamic performance for a aircraft that changes weight by 50% over its mission. Mechanisms to achieve these shape changes are designed based on two separate design methodologies: a rigid body kinematics approach and a compliant mechanism approach. A framework for optimizing mechanisms based on each approach is presented. Differences between the approaches are illustrated through the design of a mechanism for a specific set of airfoil shapes. Mechanisms are evaluated based on the error in the shapes and on the energy efficiency of the systems

    Continuous Variable Quantum State Sharing via Quantum Disentanglement

    Full text link
    Quantum state sharing is a protocol where perfect reconstruction of quantum states is achieved with incomplete or partial information in a multi-partite quantum networks. Quantum state sharing allows for secure communication in a quantum network where partial information is lost or acquired by malicious parties. This protocol utilizes entanglement for the secret state distribution, and a class of "quantum disentangling" protocols for the state reconstruction. We demonstrate a quantum state sharing protocol in which a tripartite entangled state is used to encode and distribute a secret state to three players. Any two of these players can collaborate to reconstruct the secret state, whilst individual players obtain no information. We investigate a number of quantum disentangling processes and experimentally demonstrate quantum state reconstruction using two of these protocols. We experimentally measure a fidelity, averaged over all reconstruction permutations, of F = 0.73. A result achievable only by using quantum resources.Comment: Published, Phys. Rev. A 71, 033814 (2005) (7 figures, 11 pages

    Attitude shifts and knowledge gains: Evaluating men who have sex with men sensitisation training for healthcare workers in the Western Cape, South Africa

    Get PDF
    Background: Men who have sex with men (MSM) in South Africa experience discrimination from healthcare workers (HCWs), impeding health service access.Objectives: To evaluate the outcomes of an MSM sensitisation training programme for HCWs implemented in the Western Cape province (South Africa).Methods: A training programme was developed to equip HCWs with the knowledge, awareness and skills required to provide non-discriminatory, non-judgemental and appropriate services to MSM. Overall, 592 HCWs were trained between February 2010 and May 2012. Trainees completed self-administered pre- and post-training questionnaires assessing changes in knowledge. Two-sample t-tests for proportion were used to assess changes in specific answers and the Wilcoxon rank-sum test for overall knowledge scores. Qualitative data came from anonymous post-training evaluation forms completed by all trainees, in combination with four focus group discussions (n = 28) conducted six months after their training.Results: Fourteen per cent of trainees had received previous training to counsel clients around penile–anal intercourse, and 16% had previously received training around sexual health issues affecting MSM. There was a statistically significant improvement in overall knowledge scores (80% – 87%, p &lt; 0.0001), specifically around penile–anal intercourse, substance use and depression after the training. Reductions in negative attitudes towards MSM and increased ability for HCWs to provide non-discriminatory care were reported as a result of the training.Conclusion: MSM sensitisation training for HCWs is an effective intervention to increase awareness on issues pertaining to MSM and how to engage around them, reduce discriminatory attitudes and enable the provision of non-judgemental and appropriate services by HCWs

    Expression of osteoprotegrin is enhanced in lung cancer tissues and promotes aggressive cellular traits in H3122 lung cancer cells

    Get PDF
    Background: Osteoprotegrin (OPG), a secreted protein and a member of the tumor necrosis factor receptor superfamily has been well-characterized and is an important regulator of bone remodeling by blocking osteoclast maturation thus preventing osteolysis. In recent years, OPG has been reported to have an association with the malignant capacity of various cancer types and cancer-associated bone metastasis, although the mechanisms of this are not clearly understood. Materials and Methods: In this study, OPG expression was analyzed in human lung cancer tissue and normal tissue based on the dataset of The Cancer Genome Atlas and Oncomine. The in vitro effect of OPG on H3122 lung cancer cells was also assessed by characterizing cell function following knock-down and forced overexpression in this cell line. Results: The expression of OPG was significantly increased in lung cancer tissues compared to the normal control group and OPG promoted the malignant phenotypes of H3122 cells in in vitro models. Conclusion: OPG may be a potential driver of lung cancer cells and therefore might have potential in therapy and diagnostics
    • …
    corecore