474 research outputs found

    Making the right call: Redesigning call centres from the bottom up

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    First author at the time at Department of Management, London School of Economics

    Close Binary System GO Cyg

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    In this study, we present long term photometric variations of the close binary system \astrobj{GO Cyg}. Modelling of the system shows that the primary is filling Roche lobe and the secondary of the system is almost filling its Roche lobe. The physical parameters of the system are M1=3.0±0.2MM_1 = 3.0\pm0.2 M_{\odot}, M2=1.3±0.1MM_2 = 1.3 \pm 0.1 M_{\odot}, R1=2.50±0.12RR_1 = 2.50\pm 0.12 R_{\odot}, R2=1.75±0.09RR_2 = 1.75 \pm 0.09 R_{\odot}, L1=64±9LL_1 = 64\pm 9 L_{\odot}, L2=4.9±0.7LL_2 = 4.9 \pm 0.7 L_{\odot}, and a=5.5±0.3Ra = 5.5 \pm 0.3 R_{\odot}. Our results show that \astrobj{GO Cyg} is the most massive system near contact binary (NCB). Analysis of times of the minima shows a sinusoidal variation with a period of 92.3±0.592.3\pm0.5 years due to a third body whose mass is less than 2.3MM_{\odot}. Finally a period variation rate of 1.4×109-1.4\times10^{-9} d/yr has been determined using all available light curves.Comment: Accepted for publication in New Astronomy, 18 pages, 4 figures, 7 table

    Pushing the mass limit for intact launch and photoionization of large neutral biopolymers

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    Since their first discovery by Louis Dunoyer and Otto Stern, molecular beams have conquered research and technology. However, it has remained an outstanding challenge to isolate and photoionize beams of massive neutral polypeptides. Here we show that femtosecond desorption from a matrix-free sample in high vacuum can produce biomolecular beams at least 25 times more efficiently than nanosecond techniques. While it has also been difficult to photoionize large biomolecules, we find that tailored structures with an abundant exposure of tryptophan residues at their surface can be ionized by vacuum ultraviolet light. The combination of these desorption and ionization techniques allows us to observe molecular beams of neutral polypeptides with a mass exceeding 20,000 amu. They are composed of 50 amino acids – 25 tryptophan and 25 lysine residues – and 26 fluorinated alkyl chains. The tools presented here offer a basis for the preparation, control and detection of polypeptide beams

    The Relation Between the Surface Brightness and the Diameter for Galactic Supernova Remnants

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    In this work, we have constructed a relation between the surface brightness (Σ\Sigma) and diameter (D) of Galactic C- and S-type supernova remnants (SNRs). In order to calibrate the Σ\Sigma-D dependence, we have carefully examined some intrinsic (e.g. explosion energy) and extrinsic (e.g. density of the ambient medium) properties of the remnants and, taking into account also the distance values given in the literature, we have adopted distances for some of the SNRs which have relatively more reliable distance values. These calibrator SNRs are all C- and S-type SNRs, i.e. F-type SNRs (and S-type SNR Cas A which has an exceptionally high surface brightness) are excluded. The Sigma-D relation has 2 slopes with a turning point at D=36.5 pc: Σ\Sigma(at 1 GHz)=8.46.3+19.5^{+19.5}_{-6.3}×1012\times10^{-12} D5.990.33+0.38^{{-5.99}^{+0.38}_{-0.33}} Wm2^{-2}Hz1^{-1}ster1^{-1} (for Σ\Sigma3.7×1021\le3.7\times10^{-21} Wm2^{-2}Hz1^{-1}ster1^{-1} and D\ge36.5 pc) and Σ\Sigma(at 1 GHz)=2.71.4+2.1^{+2.1}_{-1.4}×\times 1017^{-17} D2.470.16+0.20^{{-2.47}^{+0.20}_{-0.16}} Wm2^{-2}Hz1^{-1}ster1^{-1} (for Σ\Sigma>3.7×1021>3.7\times10^{-21} Wm2^{-2}Hz1^{-1}ster1^{-1} and D<<36.5 pc). We discussed the theoretical basis for the Σ\Sigma-D dependence and particularly the reasons for the change in slope of the relation were stated. Added to this, we have shown the dependence between the radio luminosity and the diameter which seems to have a slope close to zero up to about D=36.5 pc. We have also adopted distance and diameter values for all of the observed Galactic SNRs by examining all the available distance values presented in the literature together with the distances found from our Σ\Sigma-D relation.Comment: 45 pages, 2 figures, accepted for publication in Astronomical and Astrophysical Transaction

    Biochemical and aggregation analysis of Bence Jones proteins from different light chain diseases

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    Deposition of immunoglobulin light chains is a result of clonal proliferation of monoclonal plasma cells that secrete free immunoglobulin light chains, also called Bence Jones proteins (Bence Jones proteins). These Bence Jones proteins are present in circulation in large amounts and excreted in urine in various light chain diseases such as light chain amyloidosis (AL), light chain deposition disease (LCDD) and multiple myeloma (MM). BJP from patients with AL, LCDD and MM were purified from their urine and studies were performed to determine their secondary structure, thermodynamic stability and aggregate formation kinetics. Our results show that LCDD and MM proteins have the lowest free energy of folding while all proteins show similar melting temperatures. Incubation of the BJP at their melting temperature produced morphologically different aggregates: amyloid fibrils from the AL proteins, amorphous aggregates from the LCDD proteins and large spherical species from the MM proteins. The aggregates formed under in vitro conditions suggested that the various proteins derived from patients with different light chain diseases might follow different aggregation pathways

    EMPOWER-lung 1: A randomized, open-label, multi-national, phase III trial of cemiplimab, a human PD-1 monoclonal antibody, versus chemotherapy in first-line treatment of advanced non-small cell lung cancer (NSCLC) with PD-L1 50%

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    Background: Most patients (pts) with NSCLC present with advanced disease at diagnosis. Systemic therapy with platinum-based doublet chemotherapy regimens has been the standard first-line treatment for pts with advanced NSCLC whose tumours do not have EGFR, ALK, or ROS 1 mutations, but there is a need for effective treatments to improve long-term survival. With the recognition that NSCLC tumours express PD-L1, checkpoint inhibitors are being investigated in several clinical trials. There is currently only one PD-1 inhibitor approved as monotherapy in first-line treatment of NSCLC with PD-L1 expression ≥50%. In a phase 1 dose escalation and NSCLC expansion cohort, cemiplimab (REGN2810), a human monoclonal anti-PD-1, has demonstrated antitumour activity with an acceptable safety profile in anti-PD-1 naïve, pre-treated pts with NSCLC. Trial design: This is a randomised (1:1), multicentre, open-label, phase 3 study of cemiplimab versus platinum-based doublet chemotherapy in systemic treatment-naïve pts (≥18 years) with stage IIIB, IIIC or IV squamous or non-squamous NSCLC whose tumours express PD-L1 in ≥ 50% of tumour cells (NCT03088540)
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