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search.filters.applied.f.access: openAccess × End date: 2022 × Start date: 2020 × Type: Text × Subject: amplitude modulation ×

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    Radiofrequency Electromagnetic Fields Cause Non-Temperature-Induced Physical and Biological Effects in Cancer Cells
    (Basel : MDPI, 2022) Wust, Peter; Veltsista, Paraskevi D.; Oberacker, Eva; Yavvari, Prabhusrinivas; Walther, Wolfgang; Bengtsson, Olof; Sterner-Kock, Anja; Weinhart, Marie; Heyd, Florian; Grabowski, Patricia; Stintzing, Sebastian; Heinrich, Wolfgang; Stein, Ulrike; Ghadjar, Pirus
    Non-temperature-induced effects of radiofrequency electromagnetic fields (RF) have been controversial for decades. Here, we established measurement techniques to prove their existence by investigating energy deposition in tumor cells under RF exposure and upon adding amplitude modulation (AM) (AMRF). Using a preclinical device LabEHY-200 with a novel in vitro applicator, we analyzed the power deposition and system parameters for five human colorectal cancer cell lines and measured the apoptosis rates in vitro and tumor growth inhibition in vivo in comparison to water bath heating. We showed enhanced anticancer effects of RF and AMRF in vitro and in vivo and verified the non-temperature-induced origin of the effects. Furthermore, apoptotic enhancement by AM was correlated with cell membrane stiffness. Our findings not only provide a strategy to significantly enhance non-temperature-induced anticancer cell effects in vitro and in vivo but also provide a perspective for a potentially more effective tumor therapy.
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    Cavity electromechanics with parametric mechanical driving
    ([London] : Nature Publishing Group UK, 2020) Bothner, D.; Yanai, S.; Iniguez-Rabago, A.; Yuan, M.; Blanter, Ya. M.; Steele, G. A.
    Microwave optomechanical circuits have been demonstrated to be powerful tools for both exploring fundamental physics of macroscopic mechanical oscillators, as well as being promising candidates for on-chip quantum-limited microwave devices. In most experiments so far, the mechanical oscillator is either used as a passive element and its displacement is detected using the superconducting cavity, or manipulated by intracavity fields. Here, we explore the possibility to directly and parametrically manipulate the mechanical nanobeam resonator of a cavity electromechanical system, which provides additional functionality to the toolbox of microwave optomechanics. In addition to using the cavity as an interferometer to detect parametrically modulated mechanical displacement and squeezed thermomechanical motion, we demonstrate that this approach can realize a phase-sensitive parametric amplifier for intracavity microwave photons. Future perspectives of optomechanical systems with a parametrically driven mechanical oscillator include exotic bath engineering with negative effective photon temperatures, or systems with enhanced optomechanical nonlinearities.