Absorption of x-ray photons by atomic inner shells of light-element organics and biomolecules often leads to formation of dicationic electronic states and to molecular fragmentation. We investigated ...the x-ray-induced dissociation landscape of a representative medium-sized organic molecule, thiophene, by femtosecond x-ray pulses from the Super Photon Ring-8 GeV (SPring-8) Angstrom Compact Free-Electron Laser (SACLA). Holes, created in the sulfur 2p orbital by photoemission, were filled by the Auger process that created dicationic molecular states within a broad range of internal energies—a starting point particular to x-ray-induced dynamics. The evolution of the ionized molecules was monitored by a pump-probe experiment using a near-infrared (800 nm) laser pulse. Ion-ion coincidence and ion momentum analysis reveals enhanced yields of ionic fragments from multibody breakup of the ring, attributed to additional ionization of the highly excited fraction of the dicationic parent molecular states. The transient nature of the enhancement and its decay with about a 160-fs time constant indicate formation of an open-ring parent geometry and the statistical survival time of the parent species before the dissociation events. By probing specific Auger final states of transient, highly excited nature by near-infrared light, we demonstrate how pump-probe signatures can be related to the key features in dynamics during the early period of the x-ray-induced damage of organic molecules and biomolecules.
Synopsis We performed a wide-angle X-ray scattering experiment of single Xe nanoparticles using an X-ray free electron laser. We developed a novel analysis method that focuses on the angular ...correlation between plural Bragg spots in single-shot diffraction patterns. The angular correlations of the Bragg spots encode rich structural information and offer an evidence of twinning and stacking faults in Xe nanoparticles.
Rituximab (RTX), a monoclonal antibody against CD20, is known to cause fewer side effects than conventional anti-cancer drugs; however, infusion reaction (IR), which is specific to monoclonal ...antibody therapy, is frequently triggered by RTX. Therefore, we designed this study to identify risk factors based on clinical test values for developing IR after RTX administration. Eighty-nine patients with B-cell non-Hodgkin's lymphoma who had received RTX for the first time between February 2010 and March 2013, at the Gifu Municipal Hospital were enrolled as subjects. Analysis of data was conducted for 87 patients, after excluding patients whose data were missing. Univariate analysis showed significant differences in the number of patients exhibiting a soluble interleukin-2 receptor (sLL-2R) level > 2,000 U/L and hemoglobin (Hb) < lower standard limit (LSL) between the IR and non-IR groups. Multivariate analysis showed significant differences with respect to slL-2R > 2,000 U/L odds ratio (OR), 4.463; 95% confidence interval (Cl), 1.262-15.779; P = 0.020, Hb < LSL OR, 3.568; 95% CI, 1.071-11.890; P = 0.038, and steroid administration OR, 0.284; 95% Cl, 0.094-0.852; P = 0.025. Our findings show that sIL-2R > 2,000 U/L, Hb < LSL, and a lack of steroid premedication are risk factors for developing IR following RTX treatment.
In this paper, a stress-strain model of concrete that takes confinement effects into account is developed, based on the results of a series of compression loading tests of reinforced concrete column ...specimens. The specimens have circular, square, and wall-type cross sections, with various arrangements of hoop reinforcement so as to cover practical bridge column sections designed in Japan. Test results showed that three parameters-peak stress, strain at peak stress, and deteriorating rate-are significant factors for the stress-strain curve of confined concrete. These parameters were analyzed statistically based on test data and equations for estimating them were proposed. An equivalent confined section was also proposed to evaluate effect of cross ties in wall-type cross section. Test results were compared with both the proposed model and existing models. The comparison showed that the predicted stress-strain relation by the proposed model provides better agreement with the experimental results than existing models.
We have developed a dead-time free ion momentum spectroscopy technique that allows us to extract 3D momentum for each of up to 100 ions produced by a single free-electron-laser (FEL) shot, by reading ...signals from the three-layer delay-line detector by the multichannel digitizer and employing the software constant-fraction discrimination method.
We have studied charge migration and dissociation in iodine-substituted methane molecules using extremely intense and short 5.5 keV free electron laser pulses from the SACLA XFEL facility. Multiple ...core ionization down to I 2p subshells creates highly charged molecular states, the fragmentation of which was studied by ion momentum imaging multiparticle coincidence technique. We report experimental and modeling results on various dissociation pathways, fragment momentum correlations, and kinetic energy releases.
Vibrations of machines and structures vanish perfectly at a certain frequency when they have a vibration absorber without damping. But if forced frequencies vary from the anti-resonance frequency, ...their vibration amplitudes increase significantly. Then the absorber without damping cannot be applied to the structure subjected to variable frequency loads or the loads having high-frequency components. The present article discusses a method of vibration control of a structure by using the vibration absorber without damping. In this method, a variable stiffness vibration absorber is used for controlling a principal mode. The stiffness is controlled by the microcomputer under the auto-tuning algorithm for creating an anti-resonance state. The optimal vibration absorber with damping is also utilized for controlling higher modes. The analyses and the algorithm for the auto-tuning control are developed. A method to obtain optimal parameters has been presented for the vibration absorber which controls higher modes. In order to validate the control method and the analysis, experimental tests have been carried out.
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