387 research outputs found

    Cancer Patient Beliefs and Attitudes Regarding Immune Checkpoint Inhibitor Therapy

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    The development and widespread use of immune checkpoint inhibitors (ICIs) have advanced the field of oncology in a short period of time. Despite this, patient perception regarding this new medication class has not been adequately assessed, which may affect treatment decisions and adherence. The Belief about Medicines Questionnaire (BMQ) is a validated survey composed of 18 questions which analyzes patient’s beliefs about the necessity of prescribed medication and concern about the potential adverse events caused by the medication. General medication overuse and harm are also determined. This is the first study to utilize the BMQ for patients on ICI therapy

    Ionization in fast atom-atom collisions: The influence and scaling behavior of electron-electron and electron-nucleus interactions

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    We report cross sections for ionization of He coincident with electron loss from He, Li, C, O, and Ne projectiles. For He, Li, C, and O projectiles, the cross sections were measured directly, while the Ne cross sections were obtained by transforming results for He projectiles colliding with Ne. We find that, at energies of about 100–500 keV/u, neutral projectiles can ionize a He target almost as effectively as a charged projectile. The contribution to ionization due to electron-electron interactions is found to scale with the number of available projectile electrons. Comparing ionization by the bound electrons on projectiles to ionization by free electrons, we find that the cross sections for ionization by bound electrons are systematically smaller than those for free electrons

    Velocity-selective sublevel resonance of atoms with an array of current-carrying wires

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    Resonance transitions between the Zeeman sublevels of optically-polarized Rb atoms traveling through a spatially periodic magnetic field are investigated in a radio-frequency (rf) range of sub-MHz. The atomic motion induces the resonance when the Zeeman splitting is equal to the frequency at which the moving atoms feel the magnetic field oscillating. Additional temporal oscillation of the spatially periodic field splits a motion-induced resonance peak into two by an amount of this oscillation frequency. At higher oscillation frequencies, it is more suitable to consider that the resonance is mainly driven by the temporal field oscillation, with its velocity-dependence or Doppler shift caused by the atomic motion through the periodic field. A theoretical description of motion-induced resonance is also given, with emphasis on the translational energy change associated with the internal transition.Comment: 7 pages, 3 figures, final versio

    Development of a thermal ionizer as ion catcher

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    An effective ion catcher is an important part of a radioactive beam facility that is based on in-flight production. The catcher stops fast radioactive products and emits them as singly charged slow ions. Current ion catchers are based on stopping in He and H2_2 gas. However, with increasing intensity of the secondary beam the amount of ion-electron pairs created eventually prevents the electromagnetic extraction of the radioactive ions from the gas cell. In contrast, such limitations are not present in thermal ionizers used with the ISOL production technique. Therefore, at least for alkaline and alkaline earth elements, a thermal ionizer should then be preferred. An important use of the TRIÎŒ\muP facility will be for precision measurements using atom traps. Atom trapping is particularly possible for alkaline and alkaline earth isotopes. The facility can produce up to 109^9 s−1^{-1} of various Na isotopes with the in-flight method. Therefore, we have built and tested a thermal ionizer. An overview of the operation, design, construction, and commissioning of the thermal ionizer for TRIÎŒ\muP will be presented along with first results for 20^{20}Na and 21^{21}Na.Comment: 10 pages, 4 figures, XVth International Conference on Electromagnetic Isotope Separators and Techniques Related to their Applications (EMIS 2007

    Angular Distribution of Auger Electrons Emitted through the Resonant Transfer and Excitation Process Following O⁔âș+He Collisions

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    This Letter reports the first measurements of the angular distribution of Auger electrons emitted from the decay of the (1s2s2p2)3D O4+** doubly excited state formed predominantly through resonant transfer and excitation (RTE) in collisions of 13-MeV O5+ projectiles with He. The (1s2s2p2)3D angular distribution is strongly peaked along the beam direction, in agreement with recent calculations of the RTE angle-dependent impulse approximation. Furthermore, interference effects between the RTE and the elastic target direct-ionization channels are observed

    Inclusive meson production in peripheral collisions of ultrarelativistic heavy ions

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    There exist several proposals to use Weizs\"{a}cker-Williams photons generated by ultrarelativistic heavy ions to produce exotic particles in γγ\gamma\gamma fusion reactions. To estimate the background conditions for such reactions we analyze various mechanisms of meson production in very peripheral collisions of ultrarelativistic heavy ions at RHIC and LHC energies. Besides γγ\gamma\gamma fusion they include also electromagnetic γA\gamma A interactions and strong nucleon-nucleon interactions in grazing AAAA collisions. All these processes are characterised by low multiplicities of produced particles. γA\gamma A and AAAA events are simulated by corresponding Monte Carlo codes, RELDIS and FRITIOF. In each of these processes a certain fraction of pions is produced close to the mid-rapidity region that gives a background for the γγ\gamma\gamma events. The possibility of selecting mesons produced in γγ\gamma\gamma fusion events via different ptp_t cut procedures is demonstrated.Comment: 27 pages with 4 eps-figures included, uses axodraw.sty Tab.2 and 3 correcte

    Double Excitation of He by Fast Ions

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    Autoionization of He atoms following double excitation by electrons, protons, CQ+ (Q=4-6), and FQ+ (Q=7-9) ions has been studied. The electron-emission yields from the doubly excited 2s2(1S), 2s2p(1P), and 2p2(1P) states were measured at the reduced projectile energy of 1.5 MeV/nucleon for observation angles between 10°and 60°. The results indicate excitation to the 2s2(1S) and 2p2(1D) states increases as approximately Q3, while excitation to the 2s2p(1P) state varies as approximately Q2, where Q is the charge of the projectile. These charge dependences are significantly less than the Q4 dependence expected in the independent-electron model, suggesting the interaction between the two target electrons is important in creating the doubly excited states

    Electron-Electron Interactions in Transfer and Excitation in F⁞âș →₂ Collisions

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    We have measured projectile Auger electrons emitted after collisions of H-like F with H2. The cross sections for emission of KLL, KLM, KLN, and KLO Auger electrons show maxima as a function of the projectile energy. One maximum in the KLL emission cross section is due to resonant transfer and excitation. A second maximum in the cross section for KLL emission as well as the maxima in the emission cross section for the higher-n Auger electrons are attributed to a new transfer and excitation process. This involves excitation of a projectile electron by one target electron accompanied by the capture of a second target electron

    Comparison of exact and approximate cross-sections in relativistic Coulomb excitation

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    We present a new method of obtaining time-dependent matrix elements of the electromagnetic pulse produced by a highly-relativistic projectile. These matrix elements are used in a coupled-channel calculation to predict the cross-sections for population of 1- and 2-phonon states of the giant dipole resonance. Comparisons are made with the predictions of the long-wavelength and Born approximations.Comment: 26 pages, LaTex2
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