4,304 research outputs found

    One-pot silyl ketene acetal-formation-Mukaiyama–Mannich additions to imines mediated by trimethylsilyl trifluoromethanesulfonate

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    In the presence of trimethylsilyl trifluoromethanesulfonate and trialkylamine base, thioesters are readily converted to silyl ketene acetals in situ and undergo Mukaiyama–Mannich addition to N-phenylimines in one pot. The silyl triflates appears to play two roles, activating both the thioester and the imine. This process also works well when thioesters are replaced with amides, esters, or ketones. Products are isolated as desilylated anilines without the necessity of a deprotection step. Yields range from 65-99%

    Pulse-mode quantum projection synthesis: Effects of mode mismatch on optical state truncation and preparation

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    Quantum projection synthesis can be used for phase-probability-distribution measurement, optical-state truncation and preparation. The method relies on interfering optical lights, which is a major challenge in experiments performed by pulsed light sources. In the pulsed regime, the time frequency overlap of the interfering lights plays a crucial role on the efficiency of the method when they have different mode structures. In this paper, the pulsed mode projection synthesis is developed, the mode structure of interfering lights are characterized and the effect of this overlap (or mode match) on the fidelity of optical-state truncation and preparation is investigated. By introducing the positive-operator-valued measure (POVM) for the detection events in the scheme, the effect of mode mismatch between the photon-counting detectors and the incident lights are also presented.Comment: 11 pages, 4 figures, submitted to Phys. Rev.

    Impact of KRAS mutation status on the efficacy of immunotherapy in lung cancer brain metastases

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    Immune checkpoint inhibitors (ICIs) have resulted in improved outcomes in non-small cell lung cancer (NSCLC) patients. However, data demonstrating the efficacy of ICIs in NSCLC brain metastases (NSCLCBM) is limited. We analyzed overall survival (OS) in patients with NSCLCBM treated with ICIs within 90 days of NSCLCBM diagnosis (ICI-90) and compared them to patients who never received ICIs (no-ICI). We reviewed 800 patients with LCBM who were diagnosed between 2010 and 2019 at a major tertiary care institution, 97% of whom received stereotactic radiosurgery (SRS) for local treatment of BM. OS from BM was compared between the ICI-90 and no-ICI groups using the Log-Rank test and Cox proportional-hazards model. Additionally, the impact of KRAS mutational status on the efficacy of ICI was investigated. After accounting for known prognostic factors, ICI-90 in addition to SRS led to significantly improved OS compared to no-ICI (12.5 months vs 9.1, p \u3c 0.001). In the 109 patients who had both a known PD-L1 expression and KRAS status, 80.4% of patients with KRAS mutation had PD-L1 expression vs 61.9% in wild-type KRAS patients (p = 0.04). In patients without a KRAS mutation, there was no difference in OS between the ICI-90 vs no-ICI cohort with a one-year survival of 60.2% vs 54.8% (p = 0.84). However, in patients with a KRAS mutation, ICI-90 led to a one-year survival of 60.4% vs 34.1% (p = 0.004). Patients with NSCLCBM who received ICI-90 had improved OS compared to no-ICI patients. Additionally, this benefit appears to be observed primarily in patients with KRAS mutations that may drive the overall benefit, which should be taken into account in the development of future trials

    Quantum-scissors device for optical state truncation: A proposal for practical realization

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    We propose a realizable experimental scheme to prepare superposition of the vacuum and one-photon states by truncating an input coherent state. The scheme is based on the quantum scissors device proposed by Pegg, Phillips, and Barnett [Phys. Rev. Lett. 81, 1604 (1998)] and uses photon-counting detectors, a single-photon source, and linear optical elements. Realistic features of the photon counting and single-photon generation are taken into account and possible error sources are discussed together with their effect on the fidelity and efficiency of the truncation process. Wigner function and phase distribution of the generated states are given and discussed for the evaluation of the proposed scheme.Comment: 11 pages, 12 figures, the final version to appear in Phys. Rev. A64, 0638xx (2001

    Model independent results for B→D1(2420)ℓΜˉB\to D_1(2420)\ell\bar\nu and B→D2∗(2460)ℓΜˉB\to D_2^*(2460)\ell\bar\nu at order ΛQCD/mc,b\Lambda_{QCD}/m_{c,b}

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    Exclusive semileptonic B decays into D1D_1 and D2∗D_2^* mesons are investigated including order ΛQCD/mc,b\Lambda_{QCD}/m_{c,b} corrections using the heavy quark effective theory. At zero recoil, the ΛQCD/mc,b\Lambda_{QCD}/m_{c,b} corrections can be written in terms of the leading Isgur-Wise function for these transitions, τ\tau, and known meson mass splittings. We obtain an almost model independent prediction for the shape of the spectrum near zero recoil, including order ΛQCD/mc,b\Lambda_{QCD}/m_{c,b} corrections. We determine τ(1)\tau(1) from the measured B→D1ℓΜˉB\to D_1\ell\bar\nu branching ratio. Implications for B decay sum rules are discussed.Comment: 11 pages, revte

    Comparing the Anglo-American and Israeli-American special relationships in the Obama era: an alliance persistence perspective

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    The Anglo-American and Israeli-American security relationships have proved to be unusually close and have confounded expectations that they would wither away with the changing international environment. In order to explain this, the article proposes a theory of ‘alliance persistence’ that is based on reciprocity over shared geostrategic interests, sentimental attachments and institutionalized security relations. The article employs this theoretical framework to explore how Anglo-American and Israeli-American relations have developed during the Obama administration. It argues that the Anglo-American relationship has been closer because of the two countries’ shared strategic interests, whilst the Israeli-American relationship has experienced divergences in how the security interests of the two sides have been pursued. The article concludes by assessing how the two relationships will fair in the post-Obama era and argues that there are numerous areas of tension in the US-Israeli relationship that risk future tensions. Keywords: Alliance, US-UK, US-Israel, Special Relationship, Obam

    Deweyan tools for inquiry and the epistemological context of critical pedagogy

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    This article develops the notion of resistance as articulated in the literature of critical pedagogy as being both culturally sponsored and cognitively manifested. To do so, the authors draw upon John Dewey\u27s conception of tools for inquiry. Dewey provides a way to conceptualize student resistance not as a form of willful disputation, but instead as a function of socialization into cultural models of thought that actively truncate inquiry. In other words, resistance can be construed as the cognitive and emotive dimensions of the ongoing failure of institutions to provide ideas that help individuals both recognize social problems and imagine possible solutions. Focusing on Dewey\u27s epistemological framework, specifically tools for inquiry, provides a way to grasp this problem. It also affords some innovative solutions; for instance, it helps conceive of possible links between the regular curriculum and the study of specific social justice issues, a relationship that is often under-examined. The aims of critical pedagogy depend upon students developing dexterity with the conceptual tools they use to make meaning of the evidence they confront; these are background skills that the regular curriculum can be made to serve even outside social justice-focused curricula. Furthermore, the article concludes that because such inquiry involves the exploration and potential revision of students\u27 world-ordering beliefs, developing flexibility in how one thinks may be better achieved within academic subjects and topics that are not so intimately connected to students\u27 current social lives, especially where students may be directly implicated

    Semileptonic B decays to excited charmed mesons

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    Exclusive semileptonic B decays into excited charmed mesons are investigated at order ΛQCD/mQ\Lambda_{QCD}/m_Q in the heavy quark effective theory. Differential decay rates for each helicity state of the four lightest excited DD mesons (D1D_1, D2∗D_2^*, D0∗D_0^*, and D1∗D_1^*) are examined. At zero recoil, ΛQCD/mQ\Lambda_{QCD}/m_Q corrections to the matrix elements of the weak currents can be written in terms of the leading Isgur-Wise functions for the corresponding transition and meson mass splittings. A model independent prediction is found for the slope parameter of the decay rate into helicity zero D1D_1 at zero recoil. The differential decay rates are predicted, including ΛQCD/mQ\Lambda_{QCD}/m_Q corrections with some model dependence away from zero recoil and including order αs\alpha_s corrections. Ratios of various exclusive branching ratios are computed. Matrix elements of the weak currents between BB mesons and other excited charmed mesons are discussed at zero recoil to order ΛQCD/mQ\Lambda_{QCD}/m_Q. These amplitudes vanish at leading order, and can be written at order ΛQCD/mQ\Lambda_{QCD}/m_Q in terms of local matrix elements. Applications to BB decay sum rules and factorization are presented.Comment: 39 pages revtex including 10 figures, uses epsf. Substantial improvements throughout the pape

    An SU(3) model for octet baryon and meson fragmentation

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    The production of the octet of baryons and mesons in e^+ e^- collisions is analysed, based on considerations of SU(3) symmetry and a simple model for SU(3) symmetry breaking in fragmentation functions. All fragmentation functions, D_q^h(x, Q^2), describing the fragmentation of quarks into a member of the baryon octet (and similarly for fragmentation into members of the meson octet) are expressed in terms of three SU(3) symmetric functions, \alpha(x, Q^2), \beta(x, Q^2), and \gamma(x, Q^2). With the introduction of an SU(3) breaking parameter, \lambda, the model is successful in describing hadroproduction data at the Z pole. The fragmentation functions are then evolved using leading order evolution equations and good fits to currently available data at 34 GeV and at 161 GeV are obtained.Comment: 24 pages LaTeX file including 11 postscript figure file

    The CADENCE Pilot Trial – Promoting Physical Activity in Bladder Cancer Survivors: A Protocol Paper

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    Background: Participation in physical activity has been found to be beneficial for mental and physical health outcomes among cancer survivors. However, to date no intervention exists specifically to promote physical activity among bladder cancer survivors. In light of this knowledge a home-based exercise intervention was co-created for those recently diagnosed with bladder cancer. Aim: The aim of the present study, financially supported by Action Bladder Cancer UK [1], is to pilot the home-based exercise intervention tailored specifically for bladder cancer survivors (i.e. from the point of diagnosis) to improve physical and mental health outcomes (during treatment and beyond) in this population. Methods: This study will use a randomised controlled trial design. Arm one will consists of the 14 week home-based exercise intervention and arm two usual care (15 participants will be randomised to each arm). Baseline data collection will take place shortly after clinical diagnosis of bladder cancer, and follow-up approximately 7 weeks and then again approximately 14 weeks after commencement of the intervention. At each data collection point data will be collected from participants relating to demographics, physical and mental health. Participants will aslo be asked to wear an Actigraph Accelerometer at each data collection point for seven consecutive days. Immediately after baseline data collection participants in the intervention arm will be given the home-based exercise booklet. Ethics and dissemination: Ethical approval was obtained for the present study via The London- City and East Research Ethics Committee (ID:291676). Results of this study will be disseminated through peer-reviewed publications and scientific presentations
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