850 research outputs found

    Quantum repeaters with individual rare-earth ions at telecommunication wavelengths

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    We present a quantum repeater scheme that is based on individual erbium and europium ions. Erbium ions are attractive because they emit photons at telecommunication wavelength, while europium ions offer exceptional spin coherence for long-term storage. Entanglement between distant erbium ions is created by photon detection. The photon emission rate of each erbium ion is enhanced by a microcavity with high Purcell factor, as has recently been demonstrated. Entanglement is then transferred to nearby europium ions for storage. Gate operations between nearby ions are performed using dynamically controlled electric-dipole coupling. These gate operations allow entanglement swapping to be employed in order to extend the distance over which entanglement is distributed. The deterministic character of the gate operations allows improved entanglement distribution rates in comparison to atomic ensemble-based protocols. We also propose an approach that utilizes multiplexing in order to enhance the entanglement distribution rate.Comment: 13 pages, 4 figure

    Mars Spacecraft Power System Development Final Report

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    Development of optimum Mariner spacecraft power system for application to future flyby and orbiter mission

    Schnurri-3 (KRC) Interacts with c-Jun to Regulate the IL-2 Gene in T Cells

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    The activator protein 1 (AP-1) transcription factor is a key participant in the control of T cell proliferation, cytokine production, and effector function. In the immune system, AP-1 activity is highest in T cells, suggesting that a subset of T cell–specific coactivator proteins exist to selectively potentiate AP-1 function. Here, we describe that the expression of Schnurri-3, also known as κ recognition component (KRC), is induced upon T cell receptor signaling in T cells and functions to regulate the expression of the interleukin 2 (IL-2) gene. Overexpression of KRC in transformed and primary T cells leads to increased IL-2 production, whereas dominant-negative KRC, or loss of KRC protein in KRC-null mice, results in diminished IL-2 production. KRC physically associates with the c-Jun transcription factor and serves as a coactivator to augment AP-1–dependent IL-2 gene transcription

    Mathematical modeling of the dynamics of the bladder cancer and the immune response applied to a patient: Evolution and short-term prediction

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    [EN] Bladder cancer is one of the most common malignant diseases in the urinary system and a highly aggressive neoplasm. The prognosis is not favorable usually, and its evolution for particular patients is very difficult to find out. In this paper, we propose a dynamic mathematical model that describes the bladder tumor growth and the immune response evolution. This model is customized for a single patient, determining appropriate model parameter values via model calibration. Due to the uncertainty of the tumor evolution, using the calibrated model parameters, we predict the tumor size and the immune response evolution over the next few months assuming three different scenarios: favorable, neutral, and unfavorable. In the former, it is not expected any trace of the cancer in the middle of September 2018 (after 16 mo). In the neutral scenario, at the same date, a 7- to 8-mm tumor is expected. In the worst case, a 40-mm tumor is expected. The patient was cited on 10 September 2018 to check the tumor size, and according to the doctors, there was no sign of recurrence. It seems that we are in the favorable scenario. The patient will be called again for follow-up in mid-2019.This work has been supported by the Ministerio de Economía, Industria y Competitividad grant MTM2017-89664-P.Burgos-Simon, C.; García-Medina, N.; Martínez-Rodríguez, D.; Villanueva Micó, RJ. (2019). Mathematical modeling of the dynamics of the bladder cancer and the immune response applied to a patient: Evolution and short-term prediction. Mathematical Methods in the Applied Sciences. 42(17):5746-5757. https://doi.org/10.1002/mma.5536S574657574217Official Site for Spanish Medic Oncology Society.https://www.seom.org. Accessed: 25/09/2018.Greenlee, R. T., Hill-Harmon, M. B., Murray, T., & Thun, M. (2001). Cancer Statistics, 2001. CA: A Cancer Journal for Clinicians, 51(1), 15-36. doi:10.3322/canjclin.51.1.15Holmang, S., Hedelin, H., Anderstrom, C., & Johansson, S. L. (1995). The Relationship Among Multiple Recurrences, Progression and Prognosis of Patients with Stages TA and T1 Transitional Cell Cancer of the Bladder Followed for at least 20 years. Journal of Urology, 153(6), 1823-1827. doi:10.1016/s0022-5347(01)67321-xRedelman-Sidi, G., Glickman, M. S., & Bochner, B. H. (2014). The mechanism of action of BCG therapy for bladder cancer—a current perspective. Nature Reviews Urology, 11(3), 153-162. doi:10.1038/nrurol.2014.15Bladder Cancer Treatment (PDQ)‐Health Professional Version.https://www.cancer.gov/types/bladder/hp/bladder-treatment-pdq. Accessed: 25/09/2018.Bladder Cancer Treatment (PDQ)‐Patient Version.https://www.cancer.gov/types/bladder/patient/bladder-treatment-pdq. Accessed: 25/09/2018.Official Site for Hospital Universitari i Politècnic La Fe Valencia Spain.http://www.hospital-lafe.com. Accessed: 25/09/2018.Hanahan, D., & Weinberg, R. A. (2011). Hallmarks of Cancer: The Next Generation. Cell, 144(5), 646-674. doi:10.1016/j.cell.2011.02.013Dong, H., Strome, S. E., Salomao, D. R., Tamura, H., Hirano, F., Flies, D. B., … Chen, L. (2002). Tumor-associated B7-H1 promotes T-cell apoptosis: A potential mechanism of immune evasion. Nature Medicine, 8(8), 793-800. doi:10.1038/nm730Fernandez, N. C., Lozier, A., Flament, C., Ricciardi-Castagnoli, P., Bellet, D., Suter, M., … Zitvogel, L. (1999). Dendritic cells directly trigger NK cell functions: Cross-talk relevant in innate anti-tumor immune responses in vivo. Nature Medicine, 5(4), 405-411. doi:10.1038/7403Factsheet of OncoTICE 2 − 8 × 108UFC powder for suspension intravesical (in Spanish).https://www.aemps.gob.es/cima/pdfs/es/ft/61377/61377_ft.pdf. Accessed: 25/09/2018

    Energy-efficient quantum non-demolition measurement with a spin-photon interface

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    Spin-photon interfaces (SPIs) are key devices of quantum technologies, aimed at coherently transferring quantum information between spin qubits and propagating pulses of polarized light. We study the potential of a SPI for quantum non demolition (QND) measurements of a spin state. After being initialized and scattered by the SPI, the state of a light pulse depends on the spin state. It thus plays the role of a pointer state, information being encoded in the light's temporal and polarization degrees of freedom. Building on the fully Hamiltonian resolution of the spin-light dynamics, we show that quantum superpositions of zero and single photon states outperform coherent pulses of light, producing pointer states which are more distinguishable with the same photon budget. The energetic advantage provided by quantum pulses over coherent ones is maintained when information on the spin state is extracted at the classical level by performing projective measurements on the light pulses. The proposed schemes are robust against imperfections in state of the art semi-conducting devices.Comment: Accepted for publication in Quantu

    A Cost-Utility Analysis of Prostate Cancer Screening in Australia

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    Background and Objectives: The Göteborg randomised population-based prostate cancer screening trial demonstrated that Prostate Specific Antigen (PSA) based screening reduces prostate cancer deaths compared with an age matched control group. Utilising the prostate cancer detection rates from this study we have investigated the clinical and cost-effectiveness of a similar PSA-based screening strategy for an Australian population of men aged 50-69 years. Methods: A decision model that incorporated Markov processes was developed from a health system perspective.The base case scenario compared a population-based screening programme with current opportunistic screening practices. Costs, utility values, treatment patterns and background mortality rates were derived from Australian data. All costs were adjusted to reflect July 2015 Australian dollars. An alternative scenario compared systematic with opportunistic screening but with optimisation of active surveillance (AS) uptake in both groups. A discount rate of 5% for costs and benefits was utilised. Univariate and probabilistic sensitivity analyses were performed to assess the effect of variable uncertainty on model outcomes. Results: Our model very closely replicated the number of deaths from both prostate cancer and background mortality in the Göteborg study. The incremental cost per quality-adjusted life-year (QALY) for PSA screening was AU147,528.However,foryearsoflifegained(LYGs)PSAbasedscreening(AU147,528. However, for years of life gained (LYGs) PSA based screening (AU45,890/LYG) appeared more favourable. Our alternative scenario with optimised AS improved cost-utility to AU45,881/QALY,withscreeningbecomingcosteffectiveata92AU45,881/QALY, with screening becoming cost-effective at a 92% AS uptake rate. Both modelled scenarios were most sensitive to the utility of patients before and after intervention, and the discount rate used. Conclusion: PSA-based screening is not cost-effective compared to Australia’s assumed willingness to pay threshold of AU50,000/QALY. It appears more cost-effective if LYGs are used as the relevant outcome, and is more cost effective than the established Australian breast cancer screening programme on this basis. Optimised utilisation of AS increases the cost-effectiveness of prostate cancer screening dramatically

    Quantum interferences and gates with emitter-based coherent photon sources

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    Quantum emitters, such as atoms, defects in crystals, or quantum dots, are excellent sources of indistinguishable single-photons for quantum technologies. Upon coherent excitation, however, the emitted photonic state includes a vacuum component in a quantum superposition with the one-photon component. This feature has so far been largely disregarded in the framework of linear optical computing. Here we experimentally and theoretically study how the presence of photon-number coherence alters the foundation of photon-photon gates: the Hong-Ou-Mandel interference. We show that the presence of vacuum coherence not only introduces errors to standard photon indistinguishability measurements, but also results in complex quantum interference phenomena. These phenomena lead to additional entanglement that has profound impact on linear computing schemes, as we illustrate by simulating a heralded gate. Our work reveals the rich physics arising from photon-number coherence, which holds the potential to become an asset in future quantum protocols.Comment: 15 pages, 8 figure
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