1,052 research outputs found

    Dynamic elasticity by the theory of characteristics

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    Method of characteristics for analysis of elastic wave equations in Cartesian coordinate

    Recent insights into the complexity of Tank-binding kinase 1 signaling networks: The emerging role of cellular localization in the activation and substrate specificity of TBK1

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    AbstractTank-binding kinase 1 (TBK1) serves as an important component of multiple signaling pathways. While the majority of research on TBK1 has focused on its role in innate immunity, critical functions for TBK1 in autophagy and cancer are beginning to emerge. This review highlights recent structural and biochemical studies that provide insights into the molecular mechanism of TBK1 activation and summarizes what is known to date about TBK1 substrate selection. Growing evidence suggests that both processes rely on TBK1 subcellular localization, with a variety of adaptor proteins each directing TBK1 to discrete signaling complexes for different cellular responses. Further study of TBK1-mediated pathways will require careful consideration of TBK1 mechanisms of activation and specificity for proper dissection of these distinct signaling cascades

    Pressurized water reactor loss-of-coolant accidents by hypothetical vessel rupture

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    Also issued by the 1st author as an Sc. D. thesis, Massachusetts Institute of Technology. Dept. of Nuclear Engineering, 1972Includes bibliographical references (leaves 331-349

    Ensemble-averaged Rabi oscillations in a ferromagnetic CoFeB film

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    Rabi oscillations describe the process whereby electromagnetic radiation interacts coherently with spin states in a non-equilibrium interaction. To date, Rabi oscillations have not been studied in one of the most common spin ensembles in nature: spins in ferromagnets. Here, using a combination of femtosecond laser pulses and microwave excitations, we report the classical analogue of Rabi oscillations in ensemble-averaged spins of a ferromagnet. The microwave stimuli are shown to extend the coherence-time resulting in resonant spin amplification. The results we present in a dense magnetic system are qualitatively similar to those reported previously in semiconductors which have five orders of magnitude fewer spins and which require resonant optical excitations to spin-polarize the ensemble. Our study is a step towards connecting concepts used in quantum processing with spin-transport effects in ferromagnets. For example, coherent control may become possible without the complications of driving an electromagnetic field but rather by using spin-polarized currents

    Higgs-gauge boson interactions in the economical 3-3-1 model

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    Interactions among the standard model gauge bosons and scalar fields in the framework of SU(3)_C X SU(3)_L X U(1)_X gauge model with minimal (economical) Higgs content are presented. From these couplings, all scalar fields including the neutral scalar hh and the Goldstone bosons can be identified and their couplings with the usual gauge bosons such as the photon, the charged W±W^\pm and the neutral ZZ, without any additional condition, are recovered. In the effective approximation, full content of scalar sector can be recognized. The CP-odd part of Goldstone associated with the neutral non-Hermitian bilepton gauge boson GX0G_{X^0} is decouple, while its CP-even counterpart has the mixing by the same way in the gauge boson sector. Masses of the new neutral Higgs boson H10H^0_1 and the neutral non-Hermitian bilepton X0X^0 are dependent on a coefficient of Higgs self-coupling (λ1\lambda_1). Similarly, masses of the singly-charged Higgs boson H2±H_2^\pm and of the charged bilepton Y±Y^\pm are proportional through a coefficient of Higgs self-interaction (λ4\lambda_4). The hadronic cross section for production of this Higgs boson at the LHC in the effective vector boson approximation is calculated. Numerical evaluation shows that the cross section can exceed 260 fbfb.Comment: 22 pages, 1 figure, submitted to Phys. Rev.

    Adjusting Overall Survival Estimates after Treatment Switching: a Case Study in Metastatic Castration-Resistant Prostate Cancer

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    Background If patients in oncology trials receive subsequent therapy, standard intention-to-treat (ITT) analyses may inaccurately estimate the overall survival (OS) effect of the investigational product. In this context, a post-hoc analysis of the phase 3 PREVAIL study was performed with the aim to compare enzalutamide with placebo in terms of OS, adjusting for potential confounding from switching to antineoplastic therapies that are not part of standard metastatic castration-resistant prostate cancer (mCRPC) treatment pathways in some jurisdictions. Methods The PREVAIL study, which included 1717 chemotherapy-naïve men with mCRPC randomized to treatment with enzalutamide 160 mg/day or placebo, was stopped after a planned interim survival analysis revealed a benefit in favor of enzalutamide. Data from this cutoff point were confounded by switching from both arms and so were evaluated in terms of OS using two switching adjustment methods: the two-stage accelerated failure time model (two-stage method) and inverse probability of censoring weights (IPCW). Results Following adjustment for switching to nonstandard antineoplastic therapies by 14.8 (129/872 patients) and 21.3% (180/845 patients) of patients initially randomized to enzalutamide and placebo, respectively, the two-stage and IPCW methods both resulted in numerical reductions in the hazard ratio (HR) for OS [HR 0.66, 95% confidence interval (CI) 0.57–0.81 and HR 0.63, 95% CI 0.52–0.75, respectively] for enzalutamide compared to placebo versus the unadjusted ITT analysis (HR 0.71, 95% CI 0.60–0.84). These results suggest a slightly greater effect of enzalutamide on OS than originally reported. Conclusion In the PREVAIL study, switching to nonstandard antineoplastic mCRPC therapies resulted in the ITT analysis of primary data underestimating the benefit of enzalutamide on OS

    Space RACE: Capturing an Orbiting Sample and a Nation’s Imagination

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    A proposed architecture for future planetary sample return missions would consist of capturing on-orbit a sample container (collected from the surface of a planetary body and launched into space) and transferring the sample container into an earth return/reentry capsule. A challenge to this proposed architecture is integrating space applicable sensor technologies with sufficient capturing devices. While useful technologies on Earth, Earth-related rendezvous/capture technologies, such as magnetic field sensors, sound-based sensors, and Earth orbit-based radios like GPS, are not applicable to space. Inspired by the in-orbit sample capture challenge, NASA JPL has designed the Space Rendezvous And Capture Experiment (Space RACE). During this project, we would conduct a proof of concept of the Space RACE challenge by designing a small mobile robot platform traversing along a velodrome track to detect/capture a mock-up orbiting sample moving along the same track. The Space RACE challenge would inspire technologists to help deliver solutions to the on-orbit sample capture task by facilitating an exciting racing environment in order to foster the required innovation for such a critical challenge
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