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  • Publication . Preprint . Article . Conference object . 2018
    Open Access English
    Authors: 
    Moser, Daniel; Abele, Hartmut; Bosina, Joachim; Fillunger, Harald; Soldner, Torsten; Wang, Xiangzun; Zmeskal, Johann; Konrad, Gertrud;
    Publisher: HAL CCSD
    Country: France
    Project: FWF | Particles and Interaction... (W 1252)

    The beta decay of the free neutron provides several probes to test the Standard Model of particle physics as well as to search for extensions thereof. Hence, multiple experiments investigating the decay have already been performed, are under way or are being prepared. These measure the mean lifetime, angular correlation coefficients or various spectra of the charged decay products (proton and electron). NoMoS, the Neutron decay prOducts MOmentum Spectrometer, presents a novel method of momentum spectroscopy: it utilizes the $R \times B$ drift effect to disperse charged particles dependent on their momentum in an uniformly curved magnetic field. This spectrometer is designed to precisely measure momentum spectra and angular correlation coefficients in free neutron beta decay to test the Standard Model and to search for new physics beyond. With NoMoS, we aim to measure inter alia the electron-antineutrino correlation coefficient $a$ and the Fierz interference term $b$ with an ultimate precision of $\Delta a/a < 0.3\%$ and $\Delta b < 10^{-3}$ respectively. In this paper, we present the measurement principles, discuss measurement uncertainties and systematics, and give a status update. Comment: 7 pages, 4 figures, accepted to the Proceedings of the International Workshop on Particle Physics at Neutron Sources PPNS 2018, Grenoble, France, May 24-26, 2018

  • Open Access English
    Authors: 
    Ratna Tripathy; Ines Leca; Tessa van Dijk; Janneke Weiss; Bregje W.M. van Bon; Maria Christina Sergaki; Thomas Gstrein; Martin W. Breuss; Guoling Tian; Nadia Bahi-Buisson; +31 more
    Countries: Netherlands, United Kingdom, United Kingdom

    Corpus callosum malformations are associated with a broad range of neurodevelopmental diseases. We report that de novo mutations in MAST1 cause mega-corpus-callosum syndrome with cerebellar hypoplasia and cortical malformations (MCC-CH-CM) in the absence of megalencephaly. We show that MAST1 is a microtubule associated protein, that is predominantly expressed in post-mitotic neurons, and is present in both dendritic and axonal compartments. We further show that Mast1 null animals are phenotypically normal, whereas the deletion of a single amino acid (L278del) recapitulates the distinct neurological phenotype observed in patients. In animals harboring Mast1 microdeletions we find that the PI3K/AKT3/mTOR pathway is unperturbed, whereas Mast2 and Mast3 levels are diminished, indicative of a dominant negative mode of action. Finally, we report that de novo MAST1 substitutions are present in patients with autism and microcephaly, raising the prospect that mutations in this gene give rise to a spectrum of neurodevelopmental diseases.

  • Open Access English
    Authors: 
    Roderik Bruce; Mika Huhtinen; A. Manousos; F. Cerutti; Luigi Salvatore Esposito; R. Kwee-Hinzmann; A. Lechner; Alessio Mereghetti; Daniele Mirarchi; Stefano Redaelli; +1 more

    The data produced at the particle physics experiments at the Large Hadron Collider (LHC) contain not only the signals from the collisions, but also a background component from proton losses around the accelerator. Understanding, identifying and possibly mitigating this machine-induced background is essential for an efficient data taking, especially for some new physics searches. Among the sources of background are hadronic and electromagnetic showers from proton losses on nearby collimators due to beam-halo cleaning. In this article, the first dedicated LHC measurements of this type of background are presented. Controlled losses of a low-intensity beam on collimators were induced, while monitoring the backgrounds in the ATLAS detector. The results show a clear correlation between the experimental backgrounds and the setting of the tertiary collimators (TCTs). Furthermore, the results are used to show that during normal LHC physics operation the beam halo contributes to the total beam-induced background at the level of a percent or less. A second measurement, where the collimator positions are tightened during physics operation, confirms this finding by setting a limit of about 10% to the contribution from all losses on the TCTs, i.e. the sum of beam halo and elastic beam-gas scattering around the ring. Dedicated simulations of the halo-related background are presented and good agreement with data is demonstrated. These simulations provide information about features that are not experimentally accessible, like correlations between backgrounds and the distributions of proton impacts on the collimators. The results provide vital information about the dependence between background and collimator settings, which is of central importance when optimizing the LHC optics for maximum peak luminosity.

  • Open Access
    Authors: 
    Luca Pompermaier; Stefan Schwaiger; Thea Lautenschläger; L Mandombe José; Birgit Waltenberger; Hermann Stuppner;
    Publisher: Georg Thieme Verlag KG
  • Open Access English
    Authors: 
    Saiedeh Saghafi; Nikoo Haghi-Danaloo; Klaus Becker; Inna Sabdyusheva; Massih Foroughipour; Christian Hahn; Marko Pende; Martina Wanis; Michael Bergmann; Judith Stift; +3 more
    Country: Germany

    Based on the modal analysis method, we developed a model that describes the output beam of a diode-pumped solid state (DPSS) laser emitting a multimode beam. Measuring the output beam profile in the near field and at the constructed far field the individual modes, their respective contributions, and their optical parameters are determined. Using this information, the beam is optically reshaped into a quasi-Gaussian beam by the interference and superposition of the various modes. This process is controlled by a mode modulator unit that includes different meso-aspheric elements and a soft-aperture. The converted beam is guided into a second optical unit comprising achromatic-aspheric elements to produce a thin light sheet for ultramicroscopy. We found that this light sheet is markedly thinner and exhibits less side shoulders compared with a light sheet directly generated from the output of a DPSS multimode laser.

  • Open Access English
    Authors: 
    Braun, Doris E.; Lingireddy, Sreenivas R.; Beidelschies, Mark D.; Guo, Rui; Müller, Peter; Price, Sarah L.; Reutzel-Edens, Susan M.;
    Publisher: American Chemical Society
    Project: UKRI | Computationally Designed ... (EP/K039229/1), UKRI | Control and Prediction of... (EP/F03573X/1), FWF | Non-stoichiometric hydrat... (V 436)

    The solid form landscape of 5-HT2a antagonist 3-(4-(benzo[d]isoxazole-3-yl)piperazin-1-yl)-2,2-dimethylpropanoic acid hydrochloride (B5HCl) proved difficult to establish. Many crystalline materials were produced by solid form screening, but few forms readily grew high quality crystals to afford a clear picture or understanding of the solid form landscape. Careful control of crystallization conditions, a range of experimental methods, computational modeling of solvate structures, and crystal structure prediction were required to see potential arrangements of the salt in its crystal forms. Structural diversity in the solid form landscape of B5HCl was apparent in the layer structures for the anhydrate polymorphs (Forms I and II), dihydrate and a family of solvates with alcohols. The alcohol solvates, which provided a distinct packing from the neat forms and the dihydrate, form layers with conserved hydrogen bonding between B5HCl and the solvent, as well as stacking of the aromatic rings. The ability of the alcohol hydrocarbon moieties to efficiently pack between the layers accounted for the difficulty in growing some solvate crystals and the inability of other solvates to crystallize altogether. Through a combination of experiment and computation, the crystallization problems, form stability, and desolvation pathways of B5HCl have been rationalized at a molecular level. Through a combination of experiment and computation, the crystallization problems, form stability, and desolvation pathways of 3-(4-(benzo[d]isoxazole-3-yl)piperazin-1-yl)-2,2-dimethylpropanoic acid hydrochloride (B5HCl) have been rationalized at a molecular level.

  • Open Access

    Fungal infections are a serious threat, especially for immunocompromised patients. Early and reliable diagnosis is crucial to treat such infections. The bacterially produced siderophore desferrioxamine B (DFO-B) is utilized by a variety of microorganisms for iron acquisition, while mammalian cells lack the uptake of DFO-B chelates. DFO-B is clinically approved for a variety of long-term chelation therapies. Recently, DFO-B-complexed gallium-68 ([68Ga]Ga-DFO-B) was shown to enable molecular imaging of bacterial infections by positron emission tomography (PET). Here, we demonstrate that [68Ga]Ga-DFO-B can also be used for the preclinical molecular imaging of pulmonary infection caused by the fungal pathogen Aspergillus fumigatus in a rat aspergillosis model. Moreover, by combining in vitro uptake studies and the chemical modification of DFO-B, we show that the cellular transport efficacy of ferrioxamine-type siderophores is impacted by the charge of the molecule and, consequently, the environmental pH. The chemical derivatization has potential implications for its diagnostic use and characterizes transport features of ferrioxamine-type siderophores.

  • Open Access
    Authors: 
    V. G. Nebieridze; A. V. Skhirtladze; E. P. Kemertelidze; Markus Ganzera;
    Publisher: SAGE Publications

    The structures of four new flavonoid glycosides - apiotribosides A, B, C and D (1 - 4, resp.) isolated from the leaves of Tribulus terrestris L. were identified as quercetin 3- O-β-D-apiofuranosyl-(1→2)-[β-D-apiofuranosyl-(1→6)]-β-glucopyranoside (1), quercetin 3- O-β-D-apiofuranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside (2), isorhamnetin 3- O-β-D-apiofuranosyl-(1→2)-[β-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside (3), and isorhamnetin 3- O-β-D-apiofuranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside (4).

  • Open Access
    Authors: 
    Julia Eis; Ben Marzeion; Fabien Maussion;
    Publisher: Copernicus GmbH

    To provide estimates of past glacier mass changes over the course of the 20th century, an adequate initial state is required. However, empirical evidence about past glacier states at regional or global scales is largely incomplete, both spatially and temporally, calling for the use of automated numerical methods. This study presents a new way to initialize the Open Global Glacier Model from past climate information and present-day glacier states. We use synthetic experiments to show that even with these perfectly known but incomplete boundary conditions, the problem of model initialization is an ill-posed inverse problem leading to nonunique solutions, and we propose an ensemble approach as a way forward. The method works as follows: we generate a large set of physically plausible glacier candidates for a given year in the past (e.g., 1850 in the Alps), all of which are then modeled forward to the date of the observed glacier outline and evaluated by comparing the results of the forward runs to the present-day states. We test the approach on 2660 Alpine glaciers and determine error estimates of the method from the synthetic experiments. The results show that the solution is often nonunique, as many of the reconstructed initial states converge towards the observed state in the year of observation. We find that the median state of the best 5 % of all acceptable states is a reasonable best estimate. The accuracy of the method depends on the type of the considered observation for the evaluation (glacier length, area, or geometry). Trying to find past states from only present-day length instead of the full geometry leads to a sharp increase in uncertainty. Our study thus also provides quantitative information on how well the reconstructed initial glacier states are constrained through the limited information available to us. We analyze which glacier characteristics influence the reconstructability of a glacier, and we discuss ways to develop the method further for real-world applications.

  • Publication . Preprint . Article . 2021 . Embargo End Date: 01 Jan 2020
    Open Access
    Authors: 
    Aleksei Sharafiev; Mathieu L. Juan; Oscar Gargiulo; Maximilian Zanner; Stephanie Wögerer; Juan José García-Ripoll; Gerhard Kirchmair;
    Publisher: arXiv
    Country: Spain
    Project: FWF | Atoms, Light, and Molecul... (W 1259), EC | QLev4G (649008), EC | AQSuS (714235), EC | MaQSens (736943), FWF | Atoms, Light, and Molecul... (W 1259), EC | QLev4G (649008), EC | AQSuS (714235), EC | MaQSens (736943)

    At the dawn of Quantum Physics, Wigner and Weisskopf obtained a full analytical description (a photon portrait ) of the emission of a single photon by a two-level system, using the basis of frequency modes (Weisskopf and Wigner, "Zeitschrift für Physik", 63, 1930). A direct experimental reconstruction of this portrait demands an accurate measurement of a time resolved fluorescence spectrum, with high sensitivity to the off-resonant frequencies and ultrafast dynamics describing the photon creation. In this work we demonstrate such an experimental technique in a superconducting waveguide Quantum Electrodynamics (wQED) platform, using single transmon qubit and two coupled transmon qubits as quantum emitters. In both scenarios, the photon portraits agree quantitatively with the predictions of the input-output theory and qualitatively with Wigner-Weisskopf theory. We believe that our technique allows not only for interesting visualization of fundamental principles, but may serve as a tool, e.g. to realize multi-dimensional spectroscopy in waveguide Quantum Electrodynamics. AS and MZ are funded by the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation program (grant agreement No 714235). MZ is also supported by the Austrian Science Fund FWF within the DK-ALM (W1259-N27). MLJ is funded by MaQsens project (European Union’s Horizon 2020 research and innovation program, grant agreement No 736943 and European Research Council under the European Union’s Horizon 2020 research and innovation program, grant agreement No 649008). J.J.G.R. acknowledges support from project PGC2018-094792-BI00 (MCIU/AEI/FEDER, UE), CSIC Research Platform PTI-001, and CAM/FEDER project No. S2018/TCS-4342 (QUITEMAD-CM). Facilities use was supported by the KIT Nanostructure Service Laboratory (NSL). 19 pags., 10 figs. Peer reviewed

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