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Accurate spectroscopy of highly-charged high-Z ions in a storage ring is demonstrated to be feasible by the use of specially adapted crystal optics. The method has been applied for the measurement of the 1s Lamb shift in hydrogen-like gold (Au+78) in a storage ring through spectroscopy of the Lyman x-rays. This measurement represents the first result obtained for a high-Z element using high-resolution wavelength-dispersive spectroscopy in the hard x-ray regime, paving the way for sensitivity to higher- order QED effects.
Natural products (NPs) from microorganisms have been important sources for discovering new therapeutic and chemical entities. While their corresponding biosynthetic gene clusters (BGCs) can be easily identified by gene-sequence-similarity-based bioinformatics strategies, the actual access to these NPs for structure elucidation and bioactivity testing remains difficult. Deletion of the gene encoding the RNA chaperone, Hfq, results in strains losing the production of most NPs. By exchanging the native promoter of a desired BGC against an inducible promoter in Δhfq mutants, almost exclusive production of the corresponding NP from the targeted BGC in Photorhabdus, Xenorhabdus and Pseudomonas was observed including the production of several new NPs derived from previously uncharacterized non-ribosomal peptide synthetases (NRPS). This easyPACId approach (easy Promoter Activated Compound Identification) facilitates NP identification due to low interference from other NPs. Moreover, it allows direct bioactivity testing of supernatants containing secreted NPs, without laborious purification.
Ausgangspunkt ist die Beobachtung, dass sich empirisch eine inklusive Schule oftmals als eine differenzierte und differenzierende Schule darstellt. Dies bezieht sich etwa auf die Ausdifferenzierung der ‚heterogenen Lehrgruppe‘. Im zeitgemäßen inklusiven Unterricht sind allgemein- und sonderpädagogische Lehrkräfte ebenso wie Schulbegleitungen anwesend. Auch Sozialpädagog*innen und Therapeut*innen gehören vermehrt zum Schulalltag.
Vorliegende Studien dokumentieren, dass die Gestaltung inklusiver Schulen bzw. von inklusivem Unterricht von nicht intendierten Effekten und Widerständigkeiten der Akteur*innen begleitet ist. Im Beitrag werden – basierend auf der ProFiS-Studie – zwei Herausforderungen von inklusiven Schulen in den Mittelpunkt gerückt. Zum einen wird auf das Spannungsfeld von Professionalisierung und Deprofessionalisierung eingegangen. Zum anderen stellt das Verhältnis von Kategorisierung und Dekategorisierung eine Herausforderung dar. Beide Relationen sind als Spannungsverhältnisse untereinander und zueinander zu denken, die sich nicht ‚einfach‘ in eine Richtung auflösen lassen, sondern die in ihrer Widersprüchlichkeit gerade konstitutiv für die Praxis ‚inklusiver Schulen‘ wirken. Zentrale Frage des Beitrags ist, wie dieses komplexe Spannungsverhältnis der wechselseitigen Bezogenheit de/kategorisierender und de/professionalisierender Prozesse in professionellen Aktivitäten hervorgebracht wird.
The circumventricular organs (CVOs) in the central nervous system (CNS) lack a vascular blood-brain barrier (BBB), creating communication sites for sensory or secretory neurons, involved in body homeostasis. Wnt/β-catenin signaling is essential for BBB development and maintenance in endothelial cells (ECs) in most CNS vessels. Here we show that in mouse development, as well as in adult mouse and zebrafish, CVO ECs rendered Wnt-reporter negative, suggesting low level pathway activity. Characterization of the subfornical organ (SFO) vasculature revealed heterogenous claudin-5 (Cldn5) and Plvap/Meca32 expression indicative for tight and leaky vessels, respectively. Dominant, EC-specific β-catenin transcription in mice, converted phenotypically leaky into BBB-like vessels, by augmenting Cldn5+ vessels, stabilizing junctions and by reducing Plvap/Meca32+ and fenestrated vessels, resulting in decreased tracer permeability. Endothelial tightening augmented neuronal activity in the SFO of water restricted mice. Hence, regulating the SFO vessel barrier may influence neuronal function in the context of water homeostasis.
The first measurements of dielectron production at midrapidity (|ηc|<0.8) in proton-proton and proton-lead collisions at sNN−−−√ = 5.02 TeV at the LHC are presented. The dielectron cross section is measured with the ALICE detector as a function of the invariant mass mee and the pair transverse momentum pT,ee in the ranges mee < 3.5 GeV/c2 and pT,ee < 8.0 GeV/c2, in both collision systems. In proton-proton collisions, the charm and beauty cross sections are determined at midrapidity from a fit to the data with two different event generators. This complements the existing dielectron measurements performed at s√ = 7 and 13 TeV. The slope of the s√ dependence of the three measurements is described by FONLL calculations. The dielectron cross section measured in proton-lead collisions is in agreement, within the current precision, with the expected dielectron production without any nuclear matter effects for e+e− pairs from open heavy-flavor hadron decays. For the first time at LHC energies, the dielectron production in proton-lead and proton-proton collisions are directly compared at the same sNN−−−√ via the dielectron nuclear modification factor RpPb. The measurements are compared to model calculations including cold nuclear matter effects, or additional sources of dielectrons from thermal radiation.
The first measurements of dielectron production at midrapidity (|ηc|<0.8) in proton-proton and proton-lead collisions at sNN−−−√ = 5.02 TeV at the LHC are presented. The dielectron cross section is measured with the ALICE detector as a function of the invariant mass mT,ee and the pair transverse momentum pT,ee in the ranges mT,ee < 3.5 GeV/c2 and mT,ee < 8.0 GeV/c2, in both collision systems. In proton-proton collisions, the charm and beauty cross sections are determined at midrapidity from a fit to the data with two different event generators. This complements the existing dielectron measurements performed at s√ = 7 and 13 TeV. The slope of the s√ dependence of the three measurements is described by FONLL calculations. The dielectron cross section measured in proton-lead collisions is in agreement, within the current precision, with the expected dielectron production without any nuclear matter effects for e+e− pairs from open heavy-flavor hadron decays. For the first time at LHC energies, the dielectron production in proton-lead and proton-proton collisions are directly compared at the same sNN−−−√ via the dielectron nuclear modification factor RpPb. The measurements are compared to model calculations including cold nuclear matter effects, or additional sources of dielectrons from thermal radiation.
In this paper, we present an experimental and theoretical study of excitation processes for the heaviest stable helium-like ion, that is, He-like uranium occurring in relativistic collisions with hydrogen and argon targets. In particular, we concentrate on angular distributions of the characteristic Kα radiation following the K → L excitation of He-like uranium. We pay special attention to the magnetic sub-level population of the excited 1s2lj states, which is directly related to the angular distribution of the characteristic Kα radiation. We show that the experimental data can be well described by calculations taking into account the excitation by the target nucleus as well as by the target electrons. Moreover, we demonstrate for the first time an important influence of the electron-impact excitation process on the angular distributions of the Kα radiation produced by excitation of He-like uranium in collisions with different targets.
The first measurements of dielectron production at midrapidity (|ηc|<0.8) in proton-proton and proton-lead collisions at sNN−−−√ = 5.02 TeV at the LHC are presented. The dielectron cross section is measured with the ALICE detector as a function of the invariant mass mee and the pair transverse momentum pT,ee in the ranges mee < 3.5 GeV/c2 and pT,ee < 8.0 GeV/c2, in both collision systems. In proton-proton collisions, the charm and beauty cross sections are determined at midrapidity from a fit to the data with two different event generators. This complements the existing dielectron measurements performed at s√ = 7 and 13 TeV. The slope of the s√ dependence of the three measurements is described by FONLL calculations. The dielectron cross section measured in proton-lead collisions is in agreement, within the current precision, with the expected dielectron production without any nuclear matter effects for e+e− pairs from open heavy-flavor hadron decays. For the first time at LHC energies, the dielectron production in proton-lead and proton-proton collisions are directly compared at the same sNN−−−√ via the dielectron nuclear modification factor RpPb. The measurements are compared to model calculations including cold nuclear matter effects, or additional sources of dielectrons from thermal radiation.
Hintergrund: Ab Frühjahr 2020 kam es zur weltweiten Verbreitung von SARS-CoV‑2 mit der heute als erste Welle der Pandemie bezeichneten Phase ab März 2020. Diese resultierte an vielen Kliniken in Umstrukturierungen und Ressourcenverschiebungen. Ziel unserer Arbeit war die Erfassung der Auswirkungen der Pandemie auf die universitäre Hals-Nasen-Ohren(HNO)-Heilkunde für die Forschung, Lehre und Weiterbildung. Material und Methoden: Die Direktorinnen und Direktoren der 39 Universitäts-HNO-Kliniken in Deutschland wurden mithilfe einer strukturierten Online-Befragung zu den Auswirkungen der Pandemie im Zeitraum von März bis April 2020 auf die Forschung, Lehre und die Weiterbildung befragt. Ergebnisse: Alle 39 Direktorinnen und Direktoren beteiligten sich an der Umfrage. Hiervon gaben 74,4 % (29/39) an, dass es zu einer Verschlechterung ihrer Forschungstätigkeit infolge der Pandemie gekommen sei. Von 61,5 % (24/39) wurde berichtet, dass pandemiebezogene Forschungsaspekte aufgegriffen wurden. Von allen Kliniken wurde eine Einschränkung der Präsenzlehre berichtet und 97,5 % (38/39) führten neue digitale Lehrformate ein. Im Beobachtungszeitraum sahen 74,4 % der Klinikdirektoren die Weiterbildung der Assistenten nicht gefährdet. Schlussfolgerung: Die Ergebnisse geben einen Einblick in die heterogenen Auswirkungen der Pandemie. Die kurzfristige Bearbeitung pandemiebezogener Forschungsthemen und die Einführung innovativer digitaler Konzepte für die studentische Lehre belegt eindrücklich das große innovative Potenzial und die schnelle Reaktionsfähigkeit der HNO-Universitätskliniken, um auch während der Pandemie ihre Aufgaben in der Forschung, Lehre und Weiterbildung bestmöglich zu erfüllen.
TRIANNI mice carry an entire set of human immunoglobulin V region gene segments and are a powerful tool to rapidly isolate human monoclonal antibodies. After immunizing these mice with DNA encoding the spike protein of SARS-CoV-2 and boosting with spike protein, we identified 29 hybridoma antibodies that reacted with the SARS-CoV-2 spike protein. Nine antibodies neutralize SARS-CoV-2 infection at IC50 values in the subnanomolar range. ELISA-binding studies and DNA sequence analyses revealed one cluster of three clonally related neutralizing antibodies that target the receptor-binding domain and compete with the cellular receptor hACE2. A second cluster of six clonally related neutralizing antibodies bind to the N-terminal domain of the spike protein without competing with the binding of hACE2 or cluster 1 antibodies. SARS-CoV-2 mutants selected for resistance to an antibody from one cluster are still neutralized by an antibody from the other cluster. Antibodies from both clusters markedly reduced viral spread in mice transgenic for human ACE2 and protected the animals from SARS-CoV-2-induced weight loss. The two clusters of potent noncompeting SARS-CoV-2 neutralizing antibodies provide potential candidates for therapy and prophylaxis of COVID-19. The study further supports transgenic animals with a human immunoglobulin gene repertoire as a powerful platform in pandemic preparedness initiatives.