6,094 research outputs found

    Ventricular metastasis resulting in disseminated intravascular coagulation

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    BACKGROUND: Disseminated Intravascular Coagulation (DIC) complicates up to 7% of malignancies, the commonest solid organ association being adenocarcinoma. Transitional Cell Carcinoma (TCC) has rarely been associated with DIC. CASE PRESENTATION: A 74-year-old woman with TCC bladder and DIC was found to have a cardiac lesion suspicious for metastatic disease. The DIC improved with infusion of plasma and administration of Vitamin K, however the cardiac lesion was deemed inoperable and chemotherapy inappropriate; given the patients functional status. We postulate that direct activation of the coagulation cascade by the intraventricular metastasis probably triggered the coagulopathy in this patient. CONCLUSION: Cardiac metastases should be considered in cancer patients with otherwise unexplained DIC. This may influence treatment choices

    Controlling the potential landscape and normal modes of ion Coulomb crystals by a standing wave optical potential

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    Light-induced control of ions within small Coulomb crystals is investigated. By intense intracavity optical standing wave fields, subwavelength localization of individual ions is achieved for one-, two-, and three-dimensional crystals. Based on these findings, we illustrate numerically how the application of such optical potentials can be used to tailor the normal mode spectra and patterns of multi-dimensional Coulomb crystals. The results represent, among others, important steps towards controlling the crystalline structure of Coulomb crystals, investigating heat transfer processes at the quantum limit and quantum simulations of many-body systems.Comment: 6+12 pages. arXiv admin note: substantial text overlap with arXiv:1703.0508

    Raman Quantum Memory with Built-In Suppression of Four-wave Mixing Noise

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    Quantum memories are essential for large-scale quantum information networks. Along with high efficiency, storage lifetime and optical bandwidth, it is critical that the memory add negligible noise to the recalled signal. A common source of noise in optical quantum memories is spontaneous four-wave mixing. We develop and implement a technically simple scheme to suppress this noise mechanism by means of quantum interference. Using this scheme with a Raman memory in warm atomic vapour we demonstrate over an order of magnitude improvement in noise performance. Furthermore we demonstrate a method to quantify the remaining noise contributions and present a route to enable further noise suppression. Our scheme opens the way to quantum demonstrations using a broadband memory, significantly advancing the search for scalable quantum photonic networks.Comment: 6 pages, 5 figures plus Supplementary Materia

    A Survey of Eclipsing Binary Stars in the Eastern Spiral Arm of M31

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    Results of an archival survey are presented using B-band imaging of the eastern spiral arm of M31. Focusing on the eclipsing binary star population, a matched-filter technique has been used to identify 280 binary systems. Of these, 127 systems (98 of which are newly discovered) have sufficient phase coverage to allow accurate orbital periods to be determined. At least nine of these binaries are detached systems which could, in principle, be used for distance determination. The light curves of the detached and other selected systems are presented along with a discussion of some of the more interesting binaries. The impact of unresolved stellar blends on these lightcurves is considered.Comment: 10 pages, accepted for publication in MNRA

    E2F8 is a nonreceptor activator of heterotrimeric G proteins

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    BACKGROUND: Heterotrimeric G proteins are important for numerous signaling events in eukaryotes, serving primarily to transduce signals that are initiated by G protein-coupled receptors. It has recently become clear that nonreceptor activators can regulate the level of heterotrimeric G protein signaling and, in some cases, drive cycles of receptor-independent G protein activation. In this study, we used a yeast expression cloning strategy to identify novel nonreceptor activators of heterotrimeric G proteins in a human adipocyte cDNA library. RESULTS: The human transcription factor E2F8 was found to activate heterotrimeric G proteins, suggesting a specific biological role for this recently described member of the E2F family. Epistasis studies showed that E2F8 acted at the level of G proteins and was specific for Gα(i )over Gpa1. E2F8 augmented receptor-driven signaling, but also activated G proteins in the absence of a receptor. The GTPase-activating protein RGS4 antagonized the effect of E2F8, showing that E2F8's effect on Gα involved nucleotide turnover. The entire E2F8 protein was required for full activity, but the majority of the signaling activity appeared to reside in the first 200 residues. CONCLUSION: In yeast, E2F8 is a guanine nucleotide exchange factor (GEF) for the α subunit of heterotrimeric G proteins. The molecular mechanism and biological significance of this effect remain to be determined

    Optimization of log-periodic dipole antenna with LTE band rejection

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    This study presents an optimized design of a 10-dipole logperiodic antenna for UHF TV reception with LTE band rejection. The simulation of the antenna was performed in CST simulation software followed by optimization of the design using TRF (Trusted Region Framework) algorithm in the frequency range of 450 MHz-900 MHz. The parameters optimized are S11, realized gain and front-to-back ratio of the antenna. TV reception passband is 450 MHz-790 MHz and LTE band is 810 MHz-900 MHz. The proposed antenna design provides a good matching with a low S11 in the passband (470 MHz-790 MHz) and a high S11 in the stopband (i.e. LTE region of 810 MHz-900 MHz). The antenna provides a realized gain between 7 dBi and 8 dBi whereas front-to back ratio above 14 dB in the passband

    Detection limits of organic compounds achievable with intense, short-pulse lasers

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    Many organic molecules have strong absorption bands which can be accessed by ultraviolet short pulse lasers to produce efficient ionization. This resonant multiphoton ionization scheme has already been exploited as an ionization source in time-of-flight mass spectrometers used for environmental trace analysis. In the present work we quantify the ultimate potential of this technique by measuring absolute ion yields produced from the interaction of 267 nm femtosecond laser pulses with the organic molecules indole and toluene, and gases Xe, N2 and O2. Using multiphoton ionization cross sections extracted from these results, we show that the laser pulse parameters required for real-time detection of aromatic molecules at concentrations of one part per trillion in air and a limit of detection of a few attomoles are achievable with presently available commercial laser systems. The potential applications for the analysis of human breath, blood and tissue samples are discussed
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