1,505 research outputs found

    Fermi surface of the chiral topological semimetal PtGa

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    PtGa is a topological semimetal with giant spin-split Fermi arcs. Here, we report on angular-dependent de Haas-van Alphen (dHvA) measurements combined with band-structure calculations to elucidate the details of the bulk Fermi surface of PtGa. The strong spin-orbit coupling leads to eight bands crossing the Fermi energy that form a multitude of Fermi surfaces with closed extremal orbits and results in very rich dHvA spectra. The large number of experimentally observed dHvA frequencies make the assignment to the equally large number of calculated dHvA orbits challenging. Nevertheless, we find consistency between experiment and calculations verifying the topological character with maximal Chern number of the spin-split Fermi surface

    Cost-effectiveness analysis of recombinant human follicle-stimulating hormone alfa(r-hFSH) and urinary highly purified menopausal gonadotropin (hMG) based on data from a large German registry

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    This was a retrospective real-world evidence analysis of the costs per live birth for reference recombinant human follicle-stimulating hormone alfa (r-hFSH-alfa) versus highly purified urinary human menopausal gonadotropin (hMG-HP), based on data from a German in vitro fertilization registry (RecDate). Pregnancy and live birth rates from the RecDate real-world evidence study over three complete assisted reproductive technology (ART) cycles using the same gonadotropin drug were used as clinical inputs. Costs related to ART treatment and to drugs were obtained from public sources. Treatment with r-hFSH-alfa resulted in higher adjusted cumulative live birth rates versus hMG-HP after one (25.3% vs. 22.3%), two (30.9% vs. 27.5%), and three (31.9% vs. 28.6%) ART cycles. Costs per live birth were lower with r-hFSH-alfa versus hMG-HP after one (\u20ac17,938 vs. \u20ac20,054), two (\u20ac18,251 vs. \u20ac20,437), and three (\u20ac18,473 vs. \u20ac20,680) ART cycles. r-hFSH-alfa was found to be a cost-effective strategy compared with hMG-HP over three cycles

    Transduction of artificial transcriptional regulatory proteins into human cells

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    Protein transduction (PT) is a method for delivering proteins into mammalian cells. PT is accomplished by linking a small peptide tag—called a PT domain (PTD)—to a protein of interest, which generates a functional fusion protein that can penetrate efficiently into mammalian cells. In order to study the functions of a transcription factor (TF) of interest, expression plasmids that encode the TF often are transfected into mammalian cells. However, the efficiency of DNA transfection is highly variable among different cell types and is usually very low in primary cells, stem cells and tumor cells. Zinc-finger transcription factors (ZF-TFs) can be tailor-made to target almost any gene in the human genome. However, the extremely low efficiency of DNA transfection into cancer cells, both in vivo and in vitro, limits the utility of ZF-TFs. Here, we report on an artificial ZF-TF that has been fused to a well-characterized PTD from the human immunodeficiency virus-1 (HIV-1) transcriptional activator protein, Tat. This ZF-TF targeted the endogenous promoter of the human VEGF-A gene. The PTD-attached ZF-TF was delivered efficiently into human cells in vitro. In addition, the VEGF-A-specific transcriptional repressor retarded the growth rate of tumor cells in a mouse xenograft experiment

    QCD-based description of one-particle inclusive B decays

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    We discuss one-particle inclusive B decays in the limit of heavy b and c quarks. Using the large-N_C limit we factorize the non-leptonic matrix elements, and we employ a short distance expansion. Modeling the remaining nonperturbative matrix elements we obtain predictions for various decay channels and compare them with existing data.Comment: LaTeX, 22 pages, 6 figures (eps); analytical and numerical results unchanged, misrepresentation of experimental data in Fig. 5 corrected, final published versio

    The Effect of the L'Aquila Earthquake on Labour Market Outcomes

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    In this paper we analyse the effects of the L'Aquila earthquake on labour market outcomes for a period of fifteen months after its occurrence. Our estimates are based on a difference-in-differences strategy that compares residents of L'Aquila with residents of a control area before and after the earthquake. Three main results emerge from our empirical analysis: (1) the earthquake led to a modest, but significant, reduction in the probability of participating in the labour force for a period of nine months after the event; (2) while the employment likelihood decreased in the quarter immediately after the earthquake, it increased in the next four quarters; and (3) there is evidence of significant heterogeneous effects by gender and level of education

    Design and construction of an optical test bed for LISA imaging systems and tilt-to-length coupling

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    The laser interferometer space antenna (LISA) is a future space-based interferometric gravitational-wave detector consisting of three spacecraft in a triangular configuration. The interferometric measurements of path length changes between satellites will be performed on optical benches in the satellites. Angular misalignments of the interfering beams couple into the length measurement and represent a significant noise source. Imaging systems will be used to reduce this tilt-to-length coupling. We designed and constructed an optical test bed to experimentally investigate tilt-to-length coupling. It consists of two separate structures, a minimal optical bench and a telescope simulator. The minimal optical bench comprises the science interferometer where the local laser is interfered with light from a remote spacecraft. In our experiment, a simulated version of this received beam is generated on the telescope simulator. The telescope simulator provides a tilting beam, a reference interferometer and an additional static beam as a phase reference. The tilting beam can either be a flat-top beam or a Gaussian beam. We avoid tilt-to-length coupling in the reference interferometer by using a small photo diode placed at an image of the beam rotation point. We show that the test bed is operational with an initial measurement of tilt-to-length coupling without imaging systems. Furthermore, we show the design of two different imaging systems whose performance will be investigated in future experiments

    The Chemokine MIP1α/CCL3 Determines Pathology in Primary RSV Infection by Regulating the Balance of T Cell Populations in the Murine Lung

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    BACKGROUND: CD8 T cells assist in the clearance of respiratory syncytial virus (RSV) infection from the lungs. However, disease after RSV infection is in part caused by excessive T cell activity, and a balance is therefore needed between beneficial and harmful cellular immune responses. The chemokine CCL3 (MIP1alpha) is produced following RSV infection and is broadly chemotactic for both T cells and natural killer (NK) cells. We therefore investigated its role in RSV disease. METHODOLOGY/PRINCIPAL FINDINGS: CCL3 was produced biphasically, in both the early (day 1) and late (day 6-7) stages of infection. CCL3 depletion did not alter the recruitment of natural killer (NK) cells to the lungs during the early stage, but depletion did affect the later adaptive phase. While fewer T cells were recruited to the lungs of either CCL3 knockout or anti-CCL3 treated RSV infected mice, more RSV-specific pro-inflammatory T cells were recruited to the lung when CCL3 responses were impaired. This increase in RSV-specific pro-inflammatory T cells was accompanied by increased weight loss and illness after RSV infection. CONCLUSIONS/SIGNIFICANCE: CCL3 regulates the balance of T cell populations in the lung and can alter the outcome of RSV infection. Understanding the role of inflammatory mediators in the recruitment of pathogenic T cells to the lungs may lead to novel methods to control RSV disease
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