1,247 research outputs found

    Lock-in detection for pulsed electrically detected magnetic resonance

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    We show that in pulsed electrically detected magnetic resonance (pEDMR) signal modulation in combination with a lock-in detection scheme can reduce the low-frequency noise level by one order of magnitude and in addition removes the microwave-induced non-resonant background. This is exemplarily demonstrated for spin-echo measurements in phosphorus-doped Silicon. The modulation of the signal is achieved by cycling the phase of the projection pulse used in pEDMR for the read-out of the spin state.Comment: 4 pages, 2 figure

    PharmXplorer

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    Bei PharmXplorer handelt es sich um eine hypermediale multifunktionale Studien- und Weiterbildungsplattform, die Studierende, Lehrende und PraktikerInnen bei ihrer problemorientierten, kontextbezogenen und multiperspektivischen Wissens-generierung unterstützt. Die Basis der mediendidaktisch und fachdidaktisch aufbereiteten Inhalte bildet ein nach unterschiedlichen Kriterien abfragbares vernetztes Datenbanksystem, in dem alle pharmazeutisch relevanten Daten der in Österreich zugelassenen Arzneistoffe enthalten sind. 12.02.2005 | Klaus Schweiger, Alexandra Sindler, Norbert Haider & Thierry Langer (Graz

    A Dual-Lumen Extracorporeal Membrane Oxygenation Cannulation Technique Using a Mobile X-Ray Device

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    PURPOSE Dual-lumen extracorporeal membrane oxygenation (ECMO) cannulation is considered technically challenging and harbors the risk of potential life-threatening complications during cannulation. Dual-lumen cannula insertion is performed under either ultrasound or fluoroscopy guidance. Both techniques have significant disadvantages, such as examiner dependence or the necessity for transportation of the patient from the intensive care unit to the operating room. DESCRIPTION Digital, mobile x-ray devices provide a novel, examiner-independent imaging modality for bedside dual-lumen ECMO cannulation. EVALUATION From November 2019 to November 2021, 23 dual-lumen cannulations were performed in 20 patients at the Department of Thoracic Surgery, Medical University of Vienna. Twelve of 23 (52.2%) were inserted in the intensive care unit using a mobile x-ray device. The remaining patients (47.8%) were cannulated in the operating room with conventional fluoroscopy guidance. In none of the procedures did cardiovascular injuries occur. Insertion site bleeding was the most common ECMO-related complication (n = 2). CONCLUSIONS Dual-lumen cannulation using sequential x-rays can be performed safely. Especially for infectious patients or patients who require an awake ECMO, this technique overcomes disadvantages of established imaging modalities

    A dual-lumen extracorporeal membrane oxygenation cannulation technique using a mobile x-ray device

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    PURPOSE Dual-lumen extracorporeal membrane oxygenation (ECMO) cannulation is considered technically challenging and harbors the risk of potential life-threatening complications during cannulation. Dual-lumen cannula insertion is performed under either ultrasound or fluoroscopy guidance. Both techniques have significant disadvantages, such as examiner dependence or the necessity for transportation of the patient from the intensive care unit to the operating room. DESCRIPTION Digital, mobile x-ray devices provide a novel, examiner-independent imaging modality for bedside dual-lumen ECMO cannulation. EVALUATION From November 2019 to November 2021, 23 dual-lumen cannulations were performed in 20 patients at the Department of Thoracic Surgery, Medical University of Vienna. Twelve of 23 (52.2%) were inserted in the intensive care unit using a mobile x-ray device. The remaining patients (47.8%) were cannulated in the operating room with conventional fluoroscopy guidance. In none of the procedures did cardiovascular injuries occur. Insertion site bleeding was the most common ECMO-related complication (n = 2). CONCLUSIONS Dual-lumen cannulation using sequential x-rays can be performed safely. Especially for infectious patients or patients who require an awake ECMO, this technique overcomes disadvantages of established imaging modalities

    Detection of metastable electronic states by Penning trap mass spectrometry

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    State-of-the-art optical clocks achieve fractional precisions of 101810^{-18} and below using ensembles of atoms in optical lattices or individual ions in radio-frequency traps. Promising candidates for novel clocks are highly charged ions (HCIs) and nuclear transitions, which are largely insensitive to external perturbations and reach wavelengths beyond the optical range, now becoming accessible to frequency combs. However, insufficiently accurate atomic structure calculations still hinder the identification of suitable transitions in HCIs. Here, we report on the discovery of a long-lived metastable electronic state in a HCI by measuring the mass difference of the ground and the excited state in Re, the first non-destructive, direct determination of an electronic excitation energy. This result agrees with our advanced calculations, and we confirmed them with an Os ion with the same electronic configuration. We used the high-precision Penning-trap mass spectrometer PENTATRAP, unique in its synchronous use of five individual traps for simultaneous mass measurements. The cyclotron frequency ratio RR of the ion in the ground state to the metastable state could be determined to a precision of δR=11011\delta R=1\cdot 10^{-11}, unprecedented in the heavy atom regime. With a lifetime of about 130 days, the potential soft x-ray frequency reference at ν=4.861016Hz\nu=4.86\cdot 10^{16}\,\text{Hz} has a linewidth of only Δν5108Hz\Delta \nu\approx 5\cdot 10^{-8}\,\text{Hz}, and one of the highest electronic quality factor (Q=νΔν1024Q=\frac{\nu}{\Delta \nu}\approx 10^{24}) ever seen in an experiment. Our low uncertainty enables searching for more HCI soft x-ray clock transitions, needed for promising precision studies of fundamental physics in a thus far unexplored frontier

    Observation of a low-lying metastable electronic state in highly charged lead by Penning-trap mass spectrometry

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    Highly charged ions (HCIs) offer many opportunities for next-generation clock research due to the vast landscape of available electronic transitions in different charge states. The development of XUV frequency combs has enabled the search for clock transitions based on shorter wavelengths in HCIs. However, without initial knowledge of the energy of the clock states, these narrow transitions are difficult to be probed by lasers. In this Letter, we provide experimental observation and theoretical calculation of a long-lived electronic state in Nb-like Pb41+^{41+} which could be used as a clock state. With the mass spectrometer Pentatrap, the excitation energy of this metastable state is directly determined as a mass difference at an energy of 31.2(8) eV, corresponding to one of the most precise relative mass determinations to date with a fractional uncertainty of 4×10124\times10^{-12}. This experimental result agrees within 1 σ\sigma with two partially different \textit{ab initio} multi-configuration Dirac-Hartree-Fock calculations of 31.68(13) eV and 31.76(35) eV, respectively. With a calculated lifetime of 26.5(5.3) days, the transition from this metastable state to the ground state bears a quality factor of 1.1×10231.1\times10^{23} and allows for the construction of a HCI clock with a fractional frequency instability of <1019/τ<10^{-19}/\sqrt{\tau}

    Confocal laser scanning microscopy as a valuable tool in Diptera larval morphology studies

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    Larval morphology of flies is traditionally studied using light microscopy, yet in the case of fine structures compound light microscopy is limited due to problems of resolution, illumination and depth of field, not allowing for precise recognition of sclerites’ edges and interactions. Using larval instars of cyclorrhaphan Diptera, we show the usefulness of confocal laser scanning microscopy (CLSM) for studying the morphological characters of immature stages by taking advantage of the autofluorescent properties of cephaloskeleton structures. We compare data obtained from killed but unprepared larvae with those from larvae prepared by clearing according to two commonly used methods, either with potassium hydroxide or with Hoyer’s medium. We also evaluated the CLSM application for examining already slide-mounted larvae stored in museum collections and those freshly prepared. Our results indicate that CLSM and 3D reconstruction are excellent for visualizing small, compound structures of cylrorrhaphan larvae cephaloskeleton, if appropriate clearing techniques, i.e. the application of KOH, are used. Maximum intensity projection of confocal data sets obtained from material freshly prepared and that stored in museum collection does not differ. Because of this and the fact that KOH is commonly used as a clearing method to examine the cephaloskeleton of Diptera larvae, it is possible, and highly recommended, to use slides already prepared with this method for re-examination by CLSM. We conclude that CLSM application can be an invaluable source of data for studies of larval morphology of Cyclorrhapha by way of taxonomic diagnoses, character identification and improvement in characters homologization.This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited

    Penning-trap measurement of the QQ-value of the electron capture in 163Ho^{163}\mathrm{Ho} for the determination of the electron neutrino mass

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    The investigation of the absolute scale of the effective neutrino mass remains challenging due to the exclusively weak interaction of neutrinos with all known particles in the standard model of particle physics. Currently, the most precise and least model-dependent upper limit on the electron antineutrino mass is set by the KATRIN experiment from the analysis of the tritium \b{eta}-decay. Another promising approach is the electron capture in 163Ho^{163}\mathrm{Ho}, which is under investigation using microcalorimetry within the ECHo and HOLMES collab orations. An independently measured Q-value of this process is vital for the assessment of systematic uncertainties in the neutrino mass determination. Here, we report a direct, independent determination of this QQ-value by measuring the free-space cyclotron frequency ratio of highly charged ions of 163Ho^{163}\mathrm{Ho} and 163Dy^{163}\mathrm{Dy} in the Penning trap experiment \textsc{Pentatrap}. Combining this ratio with atomic physics calculations of the electronic binding energies yields a QQ-value of 2863.2(0.6)eV/c22863.2(0.6)\,\mathrm{eV}/c^{2} - a more than 50-fold improvement over the state-of-the-art. This will enable the determination of the electron neutrino mass on a sub-eV level from the analysis of the electron capture in 163Ho^{163}\mathrm{Ho}
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