170 research outputs found

    Dynamics in Stationary, Non-Globally Hyperbolic Spacetimes

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    Classically, the dynamics in a non-globally hyperbolic spacetime is ill posed. Previously, a prescription was given for defining dynamics in static spacetimes in terms of a second order operator acting on a Hilbert space defined on static slices. The present work extends this result by giving a similar prescription for defining dynamics in stationary spacetimes obeying certain mild assumptions. The prescription is defined in terms of a first order operator acting on a different Hilbert space from the one used in the static prescription. It preserves the important properties of the earlier one: the formal solution agrees with the Cauchy evolution within the domain of dependence, and smooth data of compact support always give rise to smooth solutions. In the static case, the first order formalism agrees with second order formalism (using specifically the Friedrichs extension). Applications to field quantization are also discussed.Comment: 18 pages, 1 figure, AMSLaTeX; v2: expanded discussion of field quantization, new Proposition 3.1, revised Theorem 4.2, corrected typos, and updated reference

    Volterra Distortions, Spinning Strings, and Cosmic Defects

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    Cosmic strings, as topological spacetime defects, show striking resemblance to defects in solid continua: distortions, which can be classified into disclinations and dislocations, are line-like defects characterized by a delta function-valued curvature and torsion distribution giving rise to rotational and translational holonomy. We exploit this analogy and investigate how distortions can be adapted in a systematic manner from solid state systems to Einstein-Cartan gravity. As distortions are efficiently described within the framework of a SO(3) {\rlap{\supset}\times}} T(3) gauge theory of solid continua with line defects, we are led in a straightforward way to a Poincar\'e gauge approach to gravity which is a natural framework for introducing the notion of distorted spacetimes. Constructing all ten possible distorted spacetimes, we recover, inter alia, the well-known exterior spacetime of a spin-polarized cosmic string as a special case of such a geometry. In a second step, we search for matter distributions which, in Einstein-Cartan gravity, act as sources of distorted spacetimes. The resulting solutions, appropriately matched to the distorted vacua, are cylindrically symmetric and are interpreted as spin-polarized cosmic strings and cosmic dislocations.Comment: 24 pages, LaTeX, 9 eps figures; remarks on energy conditions added, discussion extended, version to be published in Class. Quantum Gra

    Multifunctional T-cell Analyses to Study Response and Progression in Adoptive Cell Transfer Immunotherapy

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    Adoptive cell transfer (ACT) of genetically engineered T cells expressing cancer-specific T-cell receptors (TCR) is a promising cancer treatment. Here, we investigate the in vivo functional activity and dynamics of the transferred cells by analyzing samples from 3 representative patients with melanoma enrolled in a clinical trial of ACT with TCR transgenic T cells targeted against the melanosomal antigen MART-1. The analyses included evaluating 19 secreted proteins from individual cells from phenotypically defined T-cell subpopulations, as well as the enumeration of T cells with TCR antigen specificity for 36 melanoma antigens. These analyses revealed the coordinated functional dynamics of the adoptively transferred, as well as endogenous, T cells, and the importance of highly functional T cells in dominating the antitumor immune response. This study highlights the need to develop approaches to maintaining antitumor T-cell functionality with the aim of increasing the long-term efficacy of TCR-engineered ACT immunotherapy. Significance: A longitudinal functional study of adoptively transferred TCR–engineered lymphocytes yielded revealing snapshots for understanding the changes of antitumor responses over time in ACT immunotherapy of patients with advanced melanoma

    Particle detectors, geodesic motion, and the equivalence principle

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    It is shown that quantum particle detectors are not reliable probes of spacetime structure. In particular, they fail to distinguish between inertial and non-inertial motion in a general spacetime. To prove this, we consider detectors undergoing circular motion in an arbitrary static spherically symmetric spacetime, and give a necessary and sufficient condition for the response function to vanish when the field is in the static vacuum state. By examining two particular cases, we show that there is no relation, in general, between the vanishing of the response function and the fact that the detector motion is, or is not, geodesic. In static asymptotically flat spacetimes, however, all rotating detectors are excited in the static vacuum. Thus, in this particular case the static vacuum appears to be associated with a non-rotating frame. The implications of these results for the equivalence principle are considered. In particular, we discuss how to properly formulate the principle for particle detectors, and show that it is satisfied.Comment: 14 pages. Revised version, with corrections; added two references. Accepted for publication in Class. Quantum Gra

    Health-related quality of life and pain with selinexor in patients with advanced dedifferentiated liposarcoma

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    [Objective] Compare health-related quality of life (HRQoL) of selinexor versus placebo in patients with dedifferentiated liposarcoma.[Materials & methods] HRQoL was assessed at baseline and day 1 of each cycle using the European Organization for Research and Treatment of Cancer 30-item core quality of life questionnaire. Results were reported from baseline to day 169 (where exposure to treatment was maximized while maintaining adequate sample size).[Results] Pain scores worsened for placebo versus selinexor across all postbaseline visits, although differences in HRQoL at some visits were not significant. Other domains did not exhibit significant differences between arms; however, scores in both arms deteriorated over time.[Conclusion] Patients treated with selinexor reported lower rates and slower worsening of pain compared with patients who received placebo.This study was funded by Karyopharm Therapeutics, Inc. M Gounder: reports an institutional research grant from Karyopharm, personal fees from Karyopharm, Epizyme, Springworks, Daiichi, Bayer, Amgen, Tracon, Flatiron, Medscape, Physicians Education Resource, Guidepoint, GLG and UpToDate; and grants from the National Cancer Institute, National Institutes of Health (P30CA008748) – core grant (CCSG shared resources and core facility). ARA Razak: consulting/Ad board: Merck & Adaptimmune Research support: Karyopharm Therapeutics, Deciphera, Blueprint Medicines, Pfizer, Adaptimmune, Merck, Roche/Genentech, Bristol-Myers Squibb, Medimmune, Amgen, GSK, AbbVie, Iterion Therapeutics. AM Gilligan: employee of Karyopharm Therapeutics, Inc. H Leong: employee of Karyopharm Therapeutics, Inc. X Ma: employee of Karyopharm Therapeutics, Inc. N Somaiah: consultant for Deciphera, Blueprint, Bayer Research Support from Ascentage, Astra-Zeneca, Daiichi-Sankyo, Deciphera, Eli Lilly, Karyopharm and GSK. SP Chawla: consultant for Amgen, Roche, GlaxoSmithKline, Threshold Pharmaceuticals, CytRx Corporation, Ignyta, Immune Design, TRACON Pharma, Karyopharm Therapeutics, SARC: Sarcoma Alliance for Research though Collaboration, Janssen, Advenchen Laboratories, Bayer, NKMax, InhibRx. Grants or contracts from Amgen, Roche, GlaxoSmithKline, Threshold Pharmaceuticals, CytRx Corporation, Ignyta, Immune Design, TRACON Pharma, Karyopharm Therapeutics, SARC: Sarcoma Alliance for Research though Collaboration, Janssen, Advenchen Laboratories, Bayer, InhibRx, NKMax. G Grignani: consultant for Eli Lilly, Novartis, Glaxo, Pharmamar, EISAI, Bayer, Merck. SM Schuetze: consultant – NanoCarrier, UpToDate. Research funding to institution – Adaptimmune, Amgen, Blueprint, Glaxo-SmithKline, Karyopharm. B Vincenzi: Consultant for Pharmamar Eisai, Lilly, Abbott, Novartis, Accord AJ Wagner: consultant for Daiichi-Sankyo, Deciphera, Eli Lilly, Epizyme, NovoCarrier, Mundipharma, and Research Support to My Institution from Aadi Bioscience, Daiichi-Sankyo, Deciphera, Eli Lilly, Karyopharm and Plexxikon. RL Jones: consultant for Adaptimmune, Athenex, Bayer, Boehringer Ingelheim, Blueprint, Clinigen, Eisai, Epizyme, Daichii, Deciphera, Immunedesign, Lilly, Merck, Pharmamar, Springworks, Tracon, Upto Date. J Shah: employee of Karyopharm Therapeutics, Inc. S Shacham: employee of Karyopharm Therapeutics, Inc. M Kauffman: employee of Karyopharm Therapeutics, Inc. RF Riedel: ownership - Limbguard, LLC (Spouse); Institutional Clinical Research Support - AADi, AROG, Blueprint, Daiichi-Sankyo, Deciphera, Glaxo-SmithKline, Karyopharm, Ignyta, Immune Design, NanoCarrier, Oncternal, Philogen, Plexxikon, Roche, Springworks, Tracon; Consultant/Advisor - Bayer, Blueprint, Daiichi-Sankyo, Deciphera, Ignyta, NanoCarrier. S Attia: reports research funding from Desmoid Tumor Research Foundation and research funding to their institution from: AB Science, TRACON Pharma, Bayer, Novartis, Lilly, Immune Design, Karyopharm Therapeutics, Epizyme, Blueprint Medicines, Genmab, CBA Pharma, Merck, Philogen, Gradalis, Deciphera, Takeda, Incyte, Springworks, Adaptimmune, Advenchen Laboratories, Bavarian Nordic, BTG, PTC Therapeutics, GlaxoSmithKline, FORMA Therapeutics. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.Peer reviewe

    Quantum Cosmological Multidimensional Einstein-Yang-Mills Model in a RĂ—S3Ă—SdR \times S^3 \times S^d Topology

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    The quantum cosmological version of the multidimensional Einstein-Yang-Mills model in a RĂ—S3Ă—SdR \times S^3 \times S^d topology is studied in the framework of the Hartle-Hawking proposal. In contrast to previous work in the literature, we consider Yang-Mills field configurations with non-vanishing time-dependent components in both S3S^3 and SdS^d spaces. We obtain stable compactifying solutions that do correspond to extrema of the Hartle-Hawking wave function of the Universe. Subsequently, we also show that the regions where 4-dimensional metric behaves classically or quantum mechanically (i.e. regions where the metric is Lorentzian or Euclidean) will depend on the number, dd, of compact space dimensions.Comment: Plain Latex. Version that appeared in the October 15th, 1997 issue of Physical Review

    Selumetinib in combination with dacarbazine in patients with metastatic uveal melanoma: a phase III, multicentre, randomised trial (SUMIT)

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    Purpose: Uveal melanoma is the most common primary intraocular malignancy in adults with no effective systemic treatment option in the metastatic setting. Selumetinib (AZD6244, ARRY-142886) is an oral, potent, and selective MEK1/2 inhibitor with a short half-life, which demonstrated single-agent activity in patients with metastatic uveal melanoma in a randomized phase II trial. Methods: The Selumetinib (AZD6244: ARRY-142886) (Hyd-Sulfate) in Metastatic Uveal Melanoma (SUMIT) study was a phase III, double-blind trial (ClinicalTrial.gov identifier: NCT01974752) in which patients with metastatic uveal melanoma and no prior systemic therapy were randomly assigned (3:1) to selumetinib (75 mg twice daily) plus dacarbazine (1,000 mg/m2 intravenously on day 1 of every 21- day cycle) or placebo plus dacarbazine. The primary end point was progression-free survival (PFS) by blinded independent central radiologic review. Secondary end points included overall survival and objective response rate. Results: A total of 129 patients were randomly assigned to receive selumetinib plus dacarbazine (n = 97) or placebo plus dacarbazine (n = 32). In the selumetinib plus dacarbazine group, 82 patients (85%) experienced a PFS event, compared with 24 (75%) in the placebo plus dacarbazine group (median, 2.8 v 1.8 months); the hazard ratio for PFS was 0.78 (95% CI, 0.48 to 1.27; two-sided P = .32). The objective response rate was 3% with selumetinib plus dacarbazine and 0% with placebo plus dacarbazine (two-sided P = .36). At 37% maturity (n = 48 deaths), analysis of overall survival gave a hazard ratio of 0.75 (95% CI, 0.39 to 1.46; two-sided P = .40). The most frequently reported adverse events (selumetinib plus dacarbazine v placebo plus dacarbazine) were nausea (62% v 19%), rash (57% v 6%), fatigue (44% v 47%), diarrhea (44% v 22%), and peripheral edema (43% v 6%). Conclusion: In patients with metastatic uveal melanoma, the combination of selumetinib plus dacarbazine had a tolerable safety profile but did not significantly improve PFS compared with placebo plus dacarbazine

    Reversing Melanoma Cross-Resistance to BRAF and MEK Inhibitors by Co-Targeting the AKT/mTOR Pathway

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    The sustained clinical activity of the BRAF inhibitor vemurafenib (PLX4032/RG7204) in patients with BRAF(V600) mutant melanoma is limited primarily by the development of acquired resistance leading to tumor progression. Clinical trials are in progress using MEK inhibitors following disease progression in patients receiving BRAF inhibitors. However, the PI3K/AKT pathway can also induce resistance to the inhibitors of MAPK pathway.The sensitivity to vemurafenib or the MEK inhibitor AZD6244 was tested in sensitive and resistant human melanoma cell lines exploring differences in activation-associated phosphorylation levels of major signaling molecules, leading to the testing of co-inhibition of the AKT/mTOR pathway genetically and pharmacologically. There was a high degree of cross-resistance to vemurafenib and AZD6244, except in two vemurafenib-resistant cell lines that acquired a secondary mutation in NRAS. In other cell lines, acquired resistance to both drugs was associated with persistence or increase in activity of AKT pathway. siRNA-mediated gene silencing and combination therapy with an AKT inhibitor or rapamycin partially or completely reversed the resistance.Primary and acquired resistance to vemurafenib in these in vitro models results in frequent cross resistance to MEK inhibitors, except when the resistance is the result of a secondary NRAS mutation. Resistance to BRAF or MEK inhibitors is associated with the induction or persistence of activity within the AKT pathway in the presence of these drugs. This resistance can be potentially reversed by the combination of a RAF or MEK inhibitor with an AKT or mTOR inhibitor. These combinations should be available for clinical testing in patients progressing on BRAF inhibitors
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