Investigation of absorbed radiation dose in refraction-enhanced breast tomosynthesis by a Laue case analyser

An early diagnosis system for breast cancer using refraction-enhanced breast tomosynthesis is under development. Tomograms of breast specimens based on refraction-contrast were demonstrated using the simplest shift-and-add tomosynthesis algorithm. Raw projection image data of breast specimens for tomosynthesis were acquired for a total of 51 views over an angle of 50°, in increments of 1°, by rotating the object. The incident X ray was monochromatic synchrotron radiation with 20 keV. The purpose of this study was to estimate the absorbed dose of a new X-ray imaging method. As breast cancer almost always arises in glandular breast tissue, the average absorbed dose in such glandular tissue should be measured to estimate the radiation risk associated with mammography. The absorbed dose of the mammary gland due to monochromatic X rays was calculated by the Monte Carlo method, and the optimal X ray energy range for refraction-enhanced breast tomosynthesis was investigated through actual measurements. Compared with the conventional method, it was found to be below one-sixth per inspection.     

Performance of Softwood Soda-Anthraquinone Lignin–Polyethylene Glycol Derivatives as Water-Reducing Admixture for Concrete

We have developed a high-performance lignin-based water-reducing admixture. In this study, softwood soda-anthraquinone lignin was modified with mono-epoxide polyethylene glycols having chain lengths of 10, 25, and 50 mol (the number of repeating units of ethylene oxide). The mortar flow and concrete slump flow tests were used to investigate the performance of the lignin derivatives as a water-reducing admixture. All tested lignin-PEG derivatives performed considerably better than a commercial lignosulfonate water-reducing admixture in the mortar flow test. In particular, the derivative with a PEG chain length of 50 mol performed excellently in both tests. The optimum PEG content for mortar dispersion was approximately 40% for lignin derivatives with a PEG chain length of 50 mol; this content exhibited a dispersing effect that was four times higher than that of the lignosulfonate water-reducing admixture. The strength of concrete containing the lignin derivatives was almost the same strength as that of concrete containing the commercial lignosulfonate water-reducing admixture.     

Activation of Al–Cu–Fe quasicrystalline surface: fabrication of a fine nanocomposite layer with high catalytic performance

A fine layered nanocomposite with a total thickness of about 200 nm was formed on the surface of an Al₆₃Cu₂₅Fe₁₂ quasicrystal (QC). The nanocomposite was found to exhibit high catalytic performance for steam reforming of methanol. The nanocomposite was formed by a self-assembly process, by leaching the Al–Cu–Fe QC using a 5 wt% Na₂CO₃ aqueous solution followed by calcination in air at 873 K. The quasiperiodic nature of theQC played an important role in the formation of such a structure. Its high catalytic activity originated from the presence of highly dispersed copper and iron species, which also suppressed the sintering of nanoparticles.     

Conditions for the generation of nano-sized Au agglomerates in Si

The conditions for the generation of nano-sized Au agglomerates in Si, which were recently discovered by the author, have been investigated. The agglomerates can be generated under very limited conditions. The agglomerates are generated with a continuous annealing method but are not generated with a typical ordinary annealing method. They are generated at an annealing temperature of 900 °C but not at 930 °C. Agglomerates are not generated in regions less than 6 μm from the surface. They are generated in a sample that is initially supersaturated with Au atoms at 7.5 × 10¹⁶ cm^?3 but are only generated at the boundary of the out-diffusion in a sample that initially contains Au atoms at 2.5 × 10¹⁶ cm^?3. Generation of the agglomerates becomes difficult as the time to cool to the annealing temperature increases in the continuous annealing process. The generated agglomerates dissolve and disappear as the surrounding Au concentration decreases to the thermal equilibrium value, that is, as the sample recovers from the supersaturation of the surrounding Au.     

Novel Palladium‐on‐Carbon/Diphenyl Sulfide Complex for Chemoselective Hydrogenation: Preparation,Characterization, and Application

A diphenyl sulfide immobilized on palladium‐on‐carbon system, Pd/C[Ph₂S], was developed to achieve the highly chemoselective hydrogenation of alkenes, acetylenes, azides, and nitro groups in the presence of aromatic ketones, halides, benzyl esters, and N‐Cbz protective groups. Instrumental analyses of the heterogeneous catalyst demonstrated that diphenyl sulfide was embedded on Pd/C via coordination of its sulfur atom to palladium metal or physical interaction with graphite layers of the activated carbon. The catalyst could be recovered and reused at least five times without any significant loss of the reactivity.     

Convergent-beam and small-area-parallel-beam electron diffraction of icosahedral quasicrystals of a melt-quenched Al-Mn alloy

Intensity distribution in convergent-beam electron diffraction (CBED) patterns obtained from icosahedral quasicrystas of a melt-quenched Al-Mn alloy reveal that the quasicrystals do not have fivefold, threefold and twofold rotation axes and have no inversion center, although ordinary diffraction patterns obtained thus far showed these rotation symmetries. CBED patterns taken from specimen areas of about 3 nm in diameter show a deviation in geometry in spot positions from the fivefold rotation symmetry. Ring patterns due to higher-order Laue zone reflections are not observed in CBED patterns. Kikuchi bands are composed of two sub-bands in the five equivalent directions, and each band has a different intensity profile. Parallel-beam (3 × 10^-5 rad) electron diffraction patterns obtained from specimen areas less than 100 nm in diameter also show a deviation from the fivefold symmetry in spot positions and make clear that each Bragg reflection consists of many fine spots which show no fivefold symmetry. It is proven experimentally that all the observed reflections occur already in the approximation of kinematical diffraction, although their intensities may be modified by dynamical diffraction effect.     

Luminosity monitor for the venus detector at TRISTAN

We constructed a luminosity monitor of the lead-scintillator sandwich type for the VENUS detector at the e⁺e⁻ collider TRISTAN. Photomultiplier tubes with transmissive mesh dynodes could be operated fairly well in a high magnetic field and hence the readout optics system was considerably simplified. We present the performance of the luminosity monitor for e⁺e⁻ collisions at √s = 50 and 52 GeV.     

Metabolism of lipids in rat testes: Interconversions and incorporation of linoleic acid into lipid classes

Studies are reported on the mode of incorporation of linoleic acid into lipid classes of testicular lipids. 1-¹⁴C-linoleic acid was injected into the testes of adult rats of the Sprague-Dawley strain. Groups of animals were killed at 1, 3, 6, 12, 24 and 48 hr after injections of the radioactive linoleic acid. The testes of each animal and livers of some animals were excised. Fatty acid and lipid class comkposition of the extracted lipids of the testes of each animal were determined as well as the distribution of radioactvity in these compounds. Radioactive linoleic acid and fatty acids derived from it by interconversion and catabolism were incorporated into all the lipid classes. Incorporation of linoleic acid into the lipid classes was much faster than its interconversion or catabolism to other fatty acids. The importance of the fatty acid pool in the mode of incorporation of the fatty acids into the lipid classes is demonstrated.