159 research outputs found

    Region-Specific Microstructure in the Neonatal Ventricles of a Porcine Model

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    © 2018, Biomedical Engineering Society. The neonate transitions from placenta-derived oxygen, to supply from the pulmonary system, moments after birth. This requires a series of structural developments to divert more blood through the right heart and onto the lungs, with the tissue quickly remodelling to the changing ventricular workload. In some cases, however, the heart structure does not fully develop causing poor circulation and inefficient oxygenation, which is associated with an increase in mortality and morbidity. This study focuses on developing an enhanced knowledge of the 1-day old heart, quantifying the region-specific microstructural parameters of the tissue. This will enable more accurate mathematical and computational simulations of the young heart. Hearts were dissected from 12, 1-day-old deceased Yorkshire piglets (mass: 2.1–2.4kg, length: 0.38–0.51m), acquired from a breeding farm. Evans blue dye was used to label the heart equator and to demarcate the left and right ventricle free walls. Two hearts were used for three-dimensional diffusion-tensor magnetic resonance imaging, to quantify the fractional anisotropy (FA). The remaining hearts were used for two-photon excited fluorescence and second-harmonic generation microscopy, to quantify the cardiomyocyte and collagen fibril structures within the anterior and posterior aspects of the right and left ventricles. FA varied significantly across both ventricles, with the greatest in the equatorial region, followed by the base and apex. The FA in each right ventricular region was statistically greater than that in the left. Cardiomyocyte and collagen fibre rotation was greatest in the anterior wall of both ventricles, with less dispersion when compared to the posterior walls. In defining these key parameters, this study provides a valuable insight into the 1-day-old heart that will provide a valuable platform for further investigation the normal and abnormal heart using mathematical and computational models

    High efficiency of alphaviral gene transfer in combination with 5-fluorouracil in a mouse mammary tumor model

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    Copyright: Copyright 2014 Elsevier B.V., All rights reserved.Background: The combination of virotherapy and chemotherapy may enable efficient tumor regression that would be unachievable using either therapy alone. In this study, we investigated the efficiency of transgene delivery and the cytotoxic effects of alphaviral vector in combination with 5-fluorouracil (5-FU) in a mouse mammary tumor model (4 T1).Methods: Replication-deficient Semliki Forest virus (SFV) vectors carrying genes encoding fluorescent proteins were used to infect 4 T1 cell cultures treated with different doses of 5-FU. The efficiency of infection was monitored via fluorescence microscopy and quantified by fluorometry. The cytotoxicity of the combined treatment with 5-FU and alphaviral vector was measured using an MTT-based cell viability assay. In vivo experiments were performed in a subcutaneous 4 T1 mouse mammary tumor model with different 5-FU doses and an SFV vector encoding firefly luciferase.Results: Infection of 4 T1 cells with SFV prior to 5-FU treatment did not produce a synergistic anti-proliferative effect. An alternative treatment strategy, in which 5-FU was used prior to virus infection, strongly inhibited SFV expression. Nevertheless, in vivo experiments showed a significant enhancement in SFV-driven transgene (luciferase) expression upon intratumoral and intraperitoneal vector administration in 4 T1 tumor-bearing mice pretreated with 5-FU: here, we observed a positive correlation between 5-FU dose and the level of luciferase expression.Conclusions: Although 5-FU inhibited SFV-mediated transgene expression in 4 T1 cells in vitro, application of the drug in a mouse model revealed a significant enhancement of intratumoral transgene synthesis compared with 5-FU untreated mice. These results may have implications for efficient transgene delivery and the development of potent cancer treatment strategies using alphaviral vectors and 5-FU.publishersversionPeer reviewe

    2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary.

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    2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary.

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    Precise measurement of the Ds+D^+_s lifetime at Belle II

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    We measure the lifetime of the Ds+D_s^+ meson using a data sample of 207 fb1^{-1} collected by the Belle II experiment running at the SuperKEKB asymmetric-energy e+ee^+ e^- collider. The lifetime is determined by fitting the decay-time distribution of a sample of 116×103116\times 10^3 Ds+ϕπ+D_s^+\rightarrow\phi\pi^+ decays. Our result is \tau^{}_{D^+_s} = (498.7\pm 1.7\,^{+1.1}_{-0.8}) fs, where the first uncertainty is statistical and the second is systematic. This result is significantly more precise than previous measurements.Comment: 7 pages, 4 figures, to be submitted to Physical Review Letter

    Measurement of the Λc+\Lambda_c^+ lifetime

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    An absolute measurement of the Λc+\Lambda^{+}_c lifetime is reported using Λc+pKπ+\Lambda_c^+\rightarrow pK^-\pi^+ decays in events reconstructed from data collected by the Belle II experiment at the SuperKEKB asymmetric-energy electron-positron collider. The total integrated luminosity of the data sample, which was collected at center-of-mass energies at or near the Υ(4S)\Upsilon(4S) resonance, is 207.2~\mbox{fb}^{-1}. The result, τ(Λc+)=203.20±0.89(stat)±0.77(syst)\tau(\Lambda^{+}_c) = 203.20 \pm 0.89 \,\mathrm{(stat)} \pm 0.77 \,\mathrm{(syst)} fs, is the most precise measurement to date and is consistent with previous determinations.Comment: Accepted for publication in PR

    Search for an invisible ZZ^\prime in a final state with two muons and missing energy at Belle II

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    The LμLτL_{\mu}-L_{\tau} extension of the standard model predicts the existence of a lepton-flavor-universality-violating ZZ^{\prime} boson that couples only to the heavier lepton families. We search for such a ZZ^\prime through its invisible decay in the process e+eμ+μZe^+ e^- \to \mu^+ \mu^- Z^{\prime}. We use a sample of electron-positron collisions at a center-of-mass energy of 10.58GeV collected by the Belle II experiment in 2019-2020, corresponding to an integrated luminosity of 79.7fb1^{-1}. We find no excess over the expected standard-model background. We set 90%\%-confidence-level upper limits on the cross section for this process as well as on the coupling of the model, which ranges from 3×1033 \times 10^{-3} at low ZZ^{\prime} masses to 1 at ZZ^{\prime} masses of 8GeV/c2GeV/c^{2}

    Tests of light-lepton universality in angular asymmetries of B0DνB^0 \to D^{*-} \ell \nu decays

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    We present the first comprehensive tests of light-lepton universality in the angular distributions of semileptonic \Bz-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay recoil that are sensitive to lepton-universality-violating contributions. We use events where one neutral \B is fully reconstructed in \PUpsilonFourS{} \to\B\overline{B} decays in data corresponding to \lumion integrated luminosity from electron-positron collisions collected with the \belletwo detector. We find no significant deviation from the standard model expectations

    Measurement of C ⁣PC\!P asymmetries and branching-fraction ratios for B±DK±B^\pm \to DK^\pm and Dπ±D\pi^\pm with DKS0K±πD\to K^0_{\rm S} K^\pm\pi^\mp using Belle and Belle II data

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    We measure C ⁣PC\!P asymmetries and branching-fraction ratios for B±DK±B^\pm \to DK^\pm and Dπ±D\pi^\pm decays with DKS0K±πD\to K^0_{\rm S} K^\pm\pi^\mp, where DD is a superposition of D0D^0 and Dˉ0\bar{D}^0. We use the full data set of the Belle experiment, containing 772×106 BBˉ772\times 10^6~B\bar{B} pairs, and data from the Belle~II experiment, containing 387×106 BBˉ387\times 10^6~B\bar{B} pairs, both collected in electron-positron collisions at the Υ(4S)\Upsilon(4S) resonance. Our results provide model-independent information on the unitarity triangle angle ϕ3\phi_3.Comment: 26 pages, 8 figure
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