Relation between crystal structure and lattice oxygen content of sintered reaction-bonded silicon nitride

When reaction-bonded silicon nitride containing MgO/Y₂O₃ additives is sintered at three different temperatures to form sintered reaction-bonded silicon nitride (SRBSN), the thermal conductivity increases with sintering temperature. The β-Si₃N₄ (silicon nitride) crystals of SRBSN ceramics were synthesized and characterized to investigate the relation between the crystal structure and the lattice oxygen content. The hot-gas extraction measurement result and the crystal structure obtained using Rietveld analysis suggested that the unit cell size of the β-Si₃N₄ crystal increases with the decrease in the lattice oxygen content. This result is reasonable considering that the lattice oxygen with the smaller covalent radius substitutes nitrogen with the larger one in the β-Si₃N₄ crystals. The lattice oxygen content decreased with increasing sintering temperature which also correlated with increase in thermal conductivity. Moreover, it is noteworthy from the viewpoint that it may be possible to apply the lattice constant analysis for the nondestructive and simple measurement of the lattice oxygen content that deteriorates the thermal conductivity of the β-Si₃N₄ ceramics.     

Mutated KIT Tyrosine Kinase as a Novel Molecular Target in Acute Myeloid Leukemia

KIT is a type-III receptor tyrosine kinase that contributes to cell signaling in various cells. Since KIT is activated by overexpression or mutation and plays an important role in the development of some cancers, such as gastrointestinal stromal tumors and mast cell disease, molecular therapies targeting KIT mutations are being developed. In acute myeloid leukemia (AML), genome profiling via next-generation sequencing has shown that several genes that are mutated in patients with AML impact patients’ prognosis. Moreover, it was suggested that precision-medicine-based treatment using genomic data will improve treatment outcomes for AML patients. This paper presents (1) previous studies regarding the role of KIT mutations in AML, (2) the data in AML with KIT mutations from the HM-SCREEN-Japan-01 study, a genome profiling study for patients newly diagnosed with AML who are unsuitable for the standard first-line treatment (unfit) or have relapsed/refractory AML, and (3) new therapies targeting KIT mutations, such as tyrosine kinase inhibitors and heat shock protein 90 inhibitors. In this era when genome profiling via next-generation sequencing is becoming more common, KIT mutations are attractive novel molecular targets in AML.     

4He Impurity Effect on the Positive Ion Mobility in Liquid 3He

The behaviour of ⁴ He impurities has been investigated through positive ion mobility measurements in liquid ³ He at milliKelvin temperatures. In spite of the enormous surface area of the cell, the influence of ⁴ He lasted for hundreds of hours at temperatures of 20 mK. However below 10 mK, the ⁴ He impurities were quickly frozen out on the cell walls and we were free from the impurity problem. Nevertheless the multiple ion signal occasionally appeared even at a few mK, although it disappeared for a number of ionization pulses.     

Development of the Water Cooled Ceramic Breeder Test Blanket Module in Japan

The development of a Water Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) is being performed as one of the most important steps toward DEMO blanket in Japan. For the TBM testing and evaluation toward DEMO blanket, the module fabrication technology development by a candidate structural material, reduced activation martensitic/ferritic steel, F82H, is one of the most critical items from the viewpoint of realization of TBM testing in ITER. In Japan, fabrication of a real scale first wall, side walls, a breeder pebble bed box and assembling of the first wall and side walls have succeeded. Recently, the real scale partial mockup of the back wall was fabricated. The fabrication procedure of the back wall, whose thickness is up to 90 mm, was confirmed toward the fabrication of the real scale back wall by F82H. Important key technologies are almost clarified for the fabrication of the real scale TBM module mockup. From the view point of testing and evaluation, development of the technology of the blanket tritium recovery, development of advanced breeder and multiplier pebbles and the development of the blanket neutronics measurement technology are also performed. Also, tritium production and recovery test using D-T neutron in the Fusion Neutronics Source (FNS) facility has been started as the verification test of tritium production performance. This paper overviews the recent achievements of the development of the WCCB TBM in Japan.     

Computerized planning of cryosurgery using bubble packing: An experimental validation on a phantom material

The current study focuses on experimentally validating a planning scheme based on the so-called bubble packing method. This study is a part of an ongoing effort to develop computerized planning tools for cryosurgery, where bubble packing has been previously developed as a means to find an initial, uniform distribution of cryoprobes within a given domain; the so-called force-field analogy was then used to move cryoprobes to their optimum layout. However, due to the high quality of the cryoprobe distribution suggested by bubble packing and its low computational cost, it has been argued that a planning scheme based solely on bubble packing may be more clinically relevant. To test this argument, an experimental validation is performed on a simulated cross-section of the prostate, using gelatin solution as a phantom material, proprietary liquid nitrogen-based cryoprobes, and a cryoheater to simulate urethral warming. Experimental results are compared with numerically simulated temperature histories resulting from planning. Results indicate an average disagreement of 0.8 mm in identifying the freezing front location, which is an acceptable level of uncertainty in the context of prostate cryosurgery imaging.     

Improvement of polymer/fullerene solar cells by controlling geometry of the ITO substrate surface

We have found that the short-circuit current, J_sc, of polymer/fullerene [RR-P3HT/C₆₀] solar cells has a clear dependence on the surface roughness of the ITO/glass substrate. We prepared an ITO surface with an average roughness, R_a, of 0.7–11 nm by chemical etching. At first J_sc increases with the increase in ITO surface roughness and then gradually decreases. The maximum performance was obtained at R_a≈4 nm. J_sc is also high with a very flat surface of R_a=0.7 nm. This feature can be attributed to the trade-off between the increase in absorption light path length and film-quality deterioration.     

Effect of Tensile Stress on Hall Coefficients of Nickel-Base Superalloys

This paper reports on Hall Effect measurements on nickel-base superalloys and their stress dependency. The work is motivated by the desire to develop a nondestructive method of characterizing the near-surface protective residual stress in metals. Our approach is based on the assumption that the Hall coefficient deviates under the stress. It is anticipated that stress measurements based on the Hall Effect are less contaminated by cold work and other effects than conductivity-based measurements such as eddy current. The paper focuses on the two superalloys, Inconel 718 and Inconel 600. The challenge is that Hall coefficients are small in metals, and the stress-induced changes are even smaller. To measure the small effect, the lock-in technique was used, with AC injected current and AC magnetic field. It was found that the Hall coefficients indeed vary proportionally to the stress. The proportionality coefficients are significantly larger than what are estimated from the volumetric effect in a free carrier gas model. The temperature and injected current dependences of the Hall coefficients were also measured, while no dependence on the magnetic flux density was observed.     

Phase diagram of Zr–O–H ternary system

An assessment of thermodynamic information for Zr–O–H system was executed using the Calculation of Phase Diagrams (CALPHAD) technique. Phase diagram of Zr–O–H ternary system was calculated using our experimental data and those from literature for Zr–O–H system. Effect of oxygen on phase modification of Zr–H system was also discussed using the assessed thermodynamic information.     

Oxidative polymerization of phenylenediamines by enzyme and magnetic properties of the products

Oxidative polymerization of m-phenylenediamine was carried out using H₂O₂ as an oxidant and horseradish peroxidase as a catalyst in mixtures of aqueous buffer solution and 1,4-dioxane or in reversed micellar solutions. When the reaction mixture was brought into contact with a stainless steel stick, the obtained polymer responded to a permanent magnet at room temperature in the air. From the ICP emission spectroscopic analysis, it was found that these polymers contained small amounts of transition metals, such as Fe and Ni. The magnetic properties of the obtained polymers were studied with a superconducting quantum interference device (SQUID). The M (magnetization)–H (magnetic field) curves showed sigmoid behavior at 300 K, but did not exhibit a residual magnetization and a coercive force. These properties resembled those of soft ferromagnetic materials. The ferromagnetic behavior was indicated even at 800 K. Polymers of o- and p-phenylenediamines exhibited lower values of saturation magnetization than polymers of m-phenylenediamine. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 717–721, 1998