Masami Ando

Bio: Masami Ando is an academic researcher from Tokyo University of Science. The author has contributed to research in topics: Synchrotron radiation & Monochromator. The author has an hindex of 24, co-authored 214 publications receiving 3011 citations. Previous affiliations of Masami Ando include Mexican Social Security Institute & KEK.

Phonon density of states measured by inelastic nuclear resonant scattering

Abstract: The phonon density of states was measured by observing the nuclear resonant fluorescence of ${}^{57}$Fe versus the energy of incident x rays from a synchrotron radiation beam. An energy resolution of 6 meV was achieved by use of high-resolution crystal optics for the incident beam. Extremely low background levels were obtained via time discrimination of the nuclear fluorescent radiation.

Observation of Nuclear Resonant Scattering Accompanied by Phonon Excitation Using Synchrotron Radiation

Abstract: The phonon energy spectrum of a polycrystalline o. -Fe foil was observed via nuclear resonant scattering of synchrotron radiation for the first time. The measured spectrum is in good agreement with earlier neutron inelastic scattering data. One of the advantageous features of this method is that excitation of only a specific element is possible. Our results show that this method is applicable to the study of lattice dynamics and open a new field of nuclear resonant scattering spectroscopy.

X-ray resonance magnetic scattering

Abstract: A resonance-type X-ray magnetic scattering at the K -absorption edge was first observed in 220 Bragg reflection of ferromagnetic Ni single crystal. Further a theoretical discussion on the resonance magnetic scattering curve observed was carried out; A difference of the oscillator-strength density for each direction of the spins was also derived from this curve. The oscillator-strength density for minority spin excesses that for the majority spin between the Fermi level and 25 eV above the level. The difference of oscillator-strength density amounts to about 1×10 -4 /Ry at the maximum.

Simple X-Ray Dark- and Bright-Field Imaging Using Achromatic Laue Optics

Abstract: X-ray dark-field and bright-field imaging in the Laue geometry has been successfully demonstrated. Using a Bragg-case asymmetric monochromator that produces an X-ray beam with a 0.3 µrad divergence incident onto an object and a Laue geometry analyzer that can simultaneously provide dark-field imaging (DFI) and bright-field imaging (BFI). The DFI has only an X-ray refraction component on the object without illumination, while the BFI has reasonable illumination. This was achieved by a 1.075 mm thick silicon analyzer with 4, 4, 0 diffraction at 35 keV X-ray photon energy. An image of an insect embedded in polymethylmethacrylate, which can not be visualized by absorption, has been obtained.

Development of a two-dimensional imaging system for clinical applications of intravenous coronary angiography using intense synchrotron radiation produced by a multipole wiggler.

Abstract: A two-dimensional clinical intravenous coronary angiography system, comprising a large-size view area produced by asymmetrical reflection from a silicon crystal using intense synchrotron radiation from a multipole wiggler and a two-dimensional detector with an image intensifier, has been completed. An advantage of the imaging system is that two-dimensional dynamic imaging of the cardiovascular system can be achieved due to its two-dimensional radiation field. This world-first two-dimensional system has been successfully adapted to clinical applications. Details of the imaging system are described in this paper.

Principles Of Optics Electromagnetic Theory Of Propagation Interference And Diffraction Of Light

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Constitutive Expression of phVEGF165 After Intramuscular Gene Transfer Promotes Collateral Vessel Development in Patients With Critical Limb Ischemia

Abstract: Background—Preclinical studies have indicated that angiogenic growth factors can stimulate the development of collateral arteries, a concept called “therapeutic angiogenesis.” The objectives of this phase 1 clinical trial were (1) to document the safety and feasibility of intramuscular gene transfer by use of naked plasmid DNA encoding an endothelial cell mitogen and (2) to analyze potential therapeutic benefits in patients with critical limb ischemia. Methods and Results—Gene transfer was performed in 10 limbs of 9 patients with nonhealing ischemic ulcers (n=7/10) and/or rest pain (n=10/10) due to peripheral arterial disease. A total dose of 4000 μg of naked plasmid DNA encoding the 165-amino-acid isoform of human vascular endothelial growth factor (phVEGF165) was injected directly into the muscles of the ischemic limb. Gene expression was documented by a transient increase in serum levels of VEGF monitored by ELISA. The ankle-brachial index improved significantly (0.33±0.05 to 0.48±0.03, P=.02); newly v...

Hard-X-ray dark-field imaging using a grating interferometer

Abstract: Imaging with visible light today uses numerous contrast mechanisms, including bright- and dark-field contrast, phase-contrast schemes and confocal and fluorescence-based methods. X-ray imaging, on the other hand, has only recently seen the development of an analogous variety of contrast modalities. Although X-ray phase-contrast imaging could successfully be implemented at a relatively early stage with several techniques, dark-field imaging, or more generally scattering-based imaging, with hard X-rays and good signal-to-noise ratio, in practice still remains a challenging task even at highly brilliant synchrotron sources. In this letter, we report a new approach on the basis of a grating interferometer that can efficiently yield dark-field scatter images of high quality, even with conventional X-ray tube sources. Because the image contrast is formed through the mechanism of small-angle scattering, it provides complementary and otherwise inaccessible structural information about the specimen at the micrometre and submicrometre length scale. Our approach is fully compatible with conventional transmission radiography and a recently developed hard-X-ray phase-contrast imaging scheme. Applications to X-ray medical imaging, industrial non-destructive testing and security screening are discussed.

Demonstration of X-Ray Talbot Interferometry

Abstract: First Talbot interferometry in the hard X-ray region was demonstrated using a pair of transmission gratings made by forming gold stripes on glass plates. By aligning the gratings on the optical axis of X-rays with a separation that caused the Talbot effect by the first grating, moire fringes were produced inclining one grating slightly against the other around the optical axis. A phase object placed in front of the first grating was detected by moire-fringe bending. Using the technique of phase-shifting interferometry, the differential phase corresponding to the phase object could also be measured. This result suggests that X-ray Talbot interferometry is a novel and simple method for phase-sensitive X-ray radiography.

X-ray phase-contrast imaging: from pre-clinical applications towards clinics

Abstract: Phase-contrast x-ray imaging (PCI) is an innovative method that is sensitive to the refraction of the x-rays in matter. PCI is particularly adapted to visualize weakly absorbing details like those often encountered in biology and medicine. In past years, PCI has become one of the most used imaging methods in laboratory and preclinical studies: its unique characteristics allow high contrast 3D visualization of thick and complex samples even at high spatial resolution. Applications have covered a wide range of pathologies and organs, and are more and more often performed in vivo. Several techniques are now available to exploit and visualize the phase-contrast: propagation- and analyzer-based, crystal and grating interferometry and non-interferometric methods like the coded aperture. In this review, covering the last five years, we will give an overview of the main theoretical and experimental developments and of the important steps performed towards the clinical implementation of PCI.