1,128 research outputs found

    The peritoneal tumour microenvironment of high-grade serous ovarian cancer

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    High-grade serous ovarian cancer (HGSC) disseminates early and extensively throughout the peritoneal space, causing multiple lesions that are a major clinical problem. The aim of this study was to investigate the cellular composition of peritoneal tumour deposits in patient biopsies and their evolution in mouse models using immunohistochemistry, intravital microscopy, confocal microscopy, and 3D modelling. Tumour deposits from the omentum of HGSC patients contained a prominent leukocyte infiltrate of CD3(+) T cells and CD68(+) macrophages, with occasional neutrophils. Alpha-smooth muscle actin(+) (α-SMA(+) ) pericytes and/or fibroblasts surrounded these well-vascularized tumour deposits. Using the murine bowel mesentery as an accessible mouse peritoneal tissue that could be easily imaged, and two different transplantable models, we found multiple microscopic tumour deposits after i.p. injection of malignant cells. Attachment to the peritoneal surface was rapid (6-48 h) with an extensive CD45(+) leukocyte infiltrate visible by 48 h. This infiltrate persisted until end point and in the syngeneic murine ID8 model, it primarily consisted of CD3(+) T lymphocytes and CD68(+) macrophages with α-SMA(+) cells also involved from the earliest stages. A majority of tumour deposits developed above existing mesenteric blood vessels, but in avascular spaces new blood vessels tracked towards the tumour deposits by 2-3 weeks in the IGROV-1 xenografts and 6 weeks in the ID8 syngeneic model; a vigorous convoluted blood supply was established by end point. Inhibition of tumour cell cytokine production by stable expression of shRNA to CXCR4 in IGROV-1 cells did not influence the attachment of cells to the mesentery but delayed neovascularization and reduced tumour deposit size. We conclude that the multiple peritoneal tumour deposits found in HGSC patients can be modelled in the mouse. The techniques described here may be useful for assessing treatments that target the disseminated stage of this disease

    Optically opaque color-flavor locked phase inside compact stars

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    The contribution of thermally excited electron-positron pairs to the bulk properties of the color-flavor locked quark phase inside compact stars is examined. The presence of these pairs causes the photon mean free path to be much smaller than a typical core radius (R01R_0 \simeq 1 km) for all temperatures above 25 keV so that the photon contribution to the thermal conductivity is much smaller than that of the Nambu-Goldstone bosons. We also find that the electrons and positrons dominate the electrical conductivity, while their contributions to the total thermal energy is negligible.Comment: 3 pages, 2 figures. Published versio

    Thermodynamics and kinetics of boundary friction

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    A deterministic theory describing the behavior of an ultrathin lubricant film between two atomically-smooth solid surfaces is proposed. For the description of lubricant state the parameter of excess volume arising due to chaotization of solid medium structure in the course of melting is introduced. Thermodynamic and shear melting is described consistently. Dependences of friction force on temperature of lubricant, shear velocity of rubbing surfaces, and pressure upon surfaces are analyzed. Within the framework of a simple tribological model the stick-slip mode of friction, when the lubricant periodically melts and solidifies, is described. The obtained results are qualitatively compared with the experimental data.Comment: 14 pages, 6 figures, 33 reference

    The Anatomy of a Magnetar: XMM Monitoring of the Transient Anomalous X-ray Pulsar XTE J1810-197

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    We present the latest results from a multi-epoch timing and spectral study of the Transient Anomalous X-ray Pulsar XTE J1810-197. We have acquired seven observations of this pulsar with the Newton X-ray Multi-mirror Mission (XMM-Newton) over the course of two and a half years, to follow the spectral evolution as the source fades from outburst. The spectrum is arguably best characterized by a two-temperature blackbody whose luminosities are decreasing exponentially with tau_1 = 870 days and tau_2 = 280 days, respectively. The temperatures of these components are currently cooling at a rate of 22% per year from a nearly constant value recorded at earlier epochs of kT_1 = 0.25 keV and kT_2 = 0.67 keV, respectively. The new data show that the temperature T_1 and luminosity of that component have nearly returned to their historic quiescent levels and that its pulsed fraction, which has steadily decreased with time, is now consistent with the previous lack of detected pulsations in quiescence. We also summarize the detections of radio emission from XTE J1810-197, the first confirmed for any AXP. We consider possible models for the emission geometry and mechanisms of XTE J1810-197.Comment: 8 pages, 7 figures, 1 table, latex. To appear in the proceedings of "Isolated Neutron Stars", Astrophysics & Space Science, in pres

    The Multiwavelength Approach to Unidentified Gamma-Ray Sources

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    As the highest-energy photons, gamma rays have an inherent interest to astrophysicists and particle physicists studying high-energy, nonthermal processes. Gamma-ray telescopes complement those at other wavelengths, especially radio, optical, and X-ray, providing the broad, mutiwavelength coverage that has become such a powerful aspect of modern astrophysics. Multiwavelength techniques of various types have been developed to help identify and explore unidentified gamma-ray sources. This overview summarizes the ideas behind several of these methods.Comment: Proceedings of the Conference "The Multiwavelength Approach to Unidentified Sources", to appear in the journal Astrophysics and Space Scienc

    (Sub)mm Interferometry Applications in Star Formation Research

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    This contribution gives an overview about various applications of (sub)mm interferometry in star formation research. The topics covered are molecular outflows, accretion disks, fragmentation and chemical properties of low- and high-mass star-forming regions. A short outlook on the capabilities of ALMA is given as well.Comment: 20 pages, 7 figures, in proceedings to "2nd European School on Jets from Young Star: High Angular Resolution Observations". A high-resolution version of the paper can be found at http://www.mpia.de/homes/beuther/papers.htm

    Study of the radiative decay ϕηγ\phi \to \eta \gamma with CMD-2 detector

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    Using the 1.9pb11.9 pb^{-1} of data collected with the CMD-2 detector at VEPP-2M the decay mode ϕηγ\phi \to \eta \gamma, ηπ+ππ0\eta \to \pi^+\pi^-\pi^0 has been studied. The obtained branching ratio is B(ϕηγ)=(1.18±0.03±0.06)\phi \to \eta \gamma) = (1.18 \pm 0.03 \pm 0.06) %.Comment: 13 pages, 5 figures, LaTex2e, to be published in Phys. Lett.

    Study of KS KL Coupled Decays and KL -Be Interactions with the CMD-2 Detector at VEPP-2M Collider

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    The integrated luminosity about 4000 inverse nanobarn of around phi meson mass ( 5 millions of phi mesons) has been collected with the CMD-2 detector at the VEPP-2M collider. A latest analysis of the KS KL coupled decays based on 30 % of available data is presented in this paper. The KS KL pairs from phi meson decays were reconstructed in the drift chamber when both kaons decayed into two charged particles. From a sample of 1423 coupled decays a selection of candidates to the CP violating KL into pi+ pi- decay was performed. CP violating decays were not identified because of the domination of events with a KL regenerating at the Be beam pipe into KS and a background from KL semileptonic decays. The regeneration cross section of 110 MeV/c KL mesons was found to be 53 +- 17 mb in agreement with theoretical expectations. The angular distribution of KS mesons after regeneration and the total cross section of KL for Be have been measured.Comment: 14 pages, 8 figure

    Observation of KS0K_S^0 semileptonic decays with CMD-2 detector

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    The decay KS0πeνK_S^0 \to \pi e \nu has been observed by the CMD-2 detector at the e^+e^- collider VEPP-2M at Novosibirsk. Of 6 million produced KL0KS0K_L^0K_S^0 pairs, 75±1375 \pm 13 events of the KS0πeνK_S^0 \to \pi e \nu decay were selected. The corresponding branching ratio is B(KS0πeν)=(7.2±1.4)×104B(K_S^0 \to \pi e \nu)=(7.2 \pm 1.4)\times10^{-4}. This result is consistent with the evaluation of B(KS0πeν)B(K_S^0 \to \pi e \nu) from the KL0K_L^0 semileptonic rate and KS0K_S^0 lifetime assuming ΔS=ΔQ\Delta S=\Delta Q .Comment: 7 pages, 6 figures, LaTex2e. Submitted to Phys.Lett.

    Measurement of omega meson parameters in pi^+pi^-pi^0 decay mode with CMD-2

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    About 11 200 e^+e^- -> omega -> pi^+pi^-pi^0 events selected in the center of mass energy range from 760 to 810 MeV were used for the measurement of the \omega meson parameters. The following results have been obtained: sigma _{0}=(1457 \pm 23 \pm 19)nb, m_{\omega}=(782.71 \pm 0.07 \pm 0.04) MeV/c^{2}, \Gamma_{\omega}=(8.68 \pm 0.23 \pm 0.10) MeV, \Gamma_{e^+e^-}\cdot Br (\omega -> pi^+pi^-pi^0)= (0.528 \pm 0.012 \pm 0.007) \cdot 10^{-3} MeV.Comment: 8 pages, 4 figure
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