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Excellent high-temperature strength and resistance to radiation damage of 9Cr Oxide Dispersion Strengthened (9Cr-ODS) martensitic steel have been realized by nano-size Y–Ti–O complex oxide particles dispersed in the matrix and a dual phase structure consisting of α′-martensite and δ-ferrite. These are produced by mechanically alloying Fe–Cr–Ti powders with Y 2 O 3 followed by a hot-consolidation process. Therefore, the hot-consolidation process is the issue to be clarified for the formation of nano-size oxide particle and δ-ferrite. The temperature dependence of the formation and development of nano-size oxide particles and δ-ferrite using mechanically alloyed 9Cr-ODS raw powder were investigated applying X-ray Diffraction and Small Angle X-ray Scattering measurement at SPring-8 and by Electron Probe Micro Analysis. In situ heating measurement techniques with XRD and SAXS enabled real-time observation of phase transformations and allowed correlation between formation of nano-size oxide particle and δ-ferrite.

The process of residual ferrite formation and resultant high-temperature strengthening in 9Cr-ODS ferritic steel was investigated by TEM observation, dilatometric measurement and thermodynamic analysis. Formation of the residual ferrite is dominated by a balance between pinning of α–γ interfaces and the α–γ reverse transformation, and α–γ reverse transformation is affected by dissolution of carbides into the γ-matrix at the AC1 and AC3 points. The fine size of oxide particles is responsible for the higher strength of the residual ferrite containing ODS steels.

The tensile test of the recrystallized ODS ferritic steels was performed in the loading direction for the longitudinal and 45° inclined with respect to the grains alignment. The testing temperature was 800°C and the strain rate was 10–4 s–1. A clear serration structure was observed at near the grain boundaries at the surface of 45° specimen ruptured. This is a clear evidence of the occurrence of the grain boundary sliding in 45° direction. For the total strain of 12% in 45° direction, grain boundary deformation induced by sliding was estimated about 9%, whereas the amounts of the transgranular strains was 2% measured by EBSD analysis. The grain-subdivision was also identified near grain boundaries by FIB analysis, which could be caused by a dynamic recrystallization during the localized grain boundary deformation.

The recrystallization behavior of a 88% cold-rolled 15Cr–ODS ferritic steel was investigated. Specimens annealed at low and high temperatures show two different recrystallization modes. Annealing at 1000°C generates a structure consisting of coarse grains with {110} texture, while annealing at 1150°C and 1300°C produce fine grains with {111} texture. This phenomenon is ascribed to that the mobility of boundaries between {110} nuclei and {001} deformed matrix are higher than between {111} nuclei and {001} deformed matrix. Also it is found that a recovery annealing at 900°C prior to recrystallization annealing will retard recrystallization, which results in a structure of coarse grains with {110} texture even after the following annealing at 1300°C.

Connectin is an elastic protein found in vertebrate striated muscle and in some invertebrates as connectin-like proteins. In this study, we determined the structure of the amphioxus connectin gene and analyzed its sequence based on its genomic information. Amphioxus is not a vertebrate but, phylogenetically, the lowest chordate. Analysis of gene structure revealed that the amphioxus gene is approximately 430 kb in length and consists of regions with exons of repeatedly aligned immunoglobulin (Ig) domains and regions with exons of fibronectin type 3 and Ig domain repeats. With regard to this sequence, although the region corresponding to the I-band is homologous to that of invertebrate connectin-like proteins and has an Ig–PEVK region similar to that of the Neanthes sp. 4000K protein, the region corresponding to the A-band has a super-repeat structure of Ig and fibronectin type 3 domains and a kinase domain near the C-terminus, which is similar to the structure of vertebrate connectin. These findings revealed that amphioxus connectin has the domain structure of invertebrate connectin-like proteins at its N-terminus and that of vertebrate connectin at its C-terminus. Thus, amphioxus connectin has a novel structure among known connectin-like proteins. This finding suggests that the formation and maintenance of the sarcomeric structure of amphioxus striated muscle are similar to those of vertebrates; however, its elasticity is different from that of vertebrates, being more similar to that of invertebrates.

It is recognized that the high-temperature strength of 9Cr-ODS ferritic steels is maintained by the presence of a ferrite phase. In order to clarify the formation process of the ferrite phase, 9Cr-ODS ferritic steels containing various contents of Y 2 O 3 , i.e., 0 mass%, 0.1 mass%, 0.35 mass%, and 0.7 mass%, are prepared by means of mechanical alloying and hot-pressing. The ferrite phase is formed by the addition of 0.35 mass% and 0.7 mass% Y 2 O 3 ; however, it is not formed for steels without and with 0.1 mass% Y 2 O 3 normalized for 1 h at 1050 °C. It is considered from the thermodynamic analyses that the pinning of the α–γ interface motion by the dispersed Y–Ti complex oxide particles can be attributed to the retention of the ferrite phase normalized at 1050 °C, and this ferrite phase cannot be δ-ferrite that is in equilibrium with the γ-phase.

The in-reactor creep rupture tests of 11Cr–0.5Mo–2W, V, Nb F/M steel were carried out in the temperature range from 823 to 943 K using materials open test assembly in the fast flux test facility and tensile and temperature-transient-to-burst specimens were irradiated in the experimental fast reactor JOYO at temperatures between 693 and 1013 K to fast neutron doses ranging from 11 to 102 dpa. The results of post-irradiation mechanical tests showed that there was no significant degradation in tensile and transient burst strengths even after neutron irradiation below 873 K, but that there was significant degradation in both strengths at neutron irradiation above 903 K. On the other hand, the in-reactor creep rupture times were equal or greater than those of out-reactor creep even after neutron irradiation at all temperatures. This creep rupture behavior was different from that of tensile and transient burst specimens.

The size and number density of oxide nanoparticles in 9Cr-oxide dispersion strengthened (ODS) steels with different concentrations of excess O, Ti and W are quantitatively determined using small-angle neutron scattering (SANS) and small-angle X-ray scattering (SAXS). Based on the difference of the SANS and SAXS intensity in absolute units, the “alloy contrast variation (ACV) method” has been used to determine the compositions of the oxide nanoprecipitates. The results indicate that the finest size and highest number density of oxide nanoparticles is obtained by suppressing the amount of excess O and increasing the amount of Ti. The ACV method indicates that the finest oxide nanoparticles have a chemical composition close to Y2Ti2O7.

Oxide dispersion strengthened (ODS) ferritic steels, which are the most promising candidate materials for advanced fast reactor fuel elements, have exceptional creep strength at 973 K. The superior creep property of 9Cr-ODS ferritic steels is ascribed to the formation of a nonequilibrium phase, designated as the residual ferrite. The yield strength of the residual ferrite itself has been determined to be as high as 1360 MPa at room temperature from nanoindentation measurements. The creep strength is also enhanced by minimizing the number of packet boundaries induced by the martensitic phase transformation. The creep strain occurs at a lower stress than that necessary for the deformation of the intragrain regions, which are strengthened by an interaction between nanosize oxide particles and dislocations; this occurs by sliding at weaker regions such as at the grain boundaries and packet boundaries. It is found that 9Cr-ODS ferritic steels behave as fiber composite materials comprising the harder residual ferrite and the softer tempered martensite.

This paper discusses the effects of small amount of Al contamination (

Nanometer size oxide particles in 9Cr-ODS steel are dispersed finely and densely in a matrix by the hot-solidification process. The size and density distribution of dispersed oxide particles is recognized as one of the main issues for ensuring good microstructural stability and high temperature strength in a high temperature (

The effects of chemical compositions on the microstructure and high-temperature creep strength of 9Cr-ODS steel was discussed in the light of quantitative data of δ-ferrite proportion and nano-size oxide particle dispersion, which were evaluated by dilatometric analysis and small angle neutron/X-ray scattering analysis, respectively. These quantitative data are well consistent with the conventional data obtained by transmission electron microscope. Both data indicate that the important microstructural feature for creep strength improvement of the 9Cr-ODS steel is the number density of nano-size oxide particles, and ferrite/martensite (F/M) duplex structure is favorable for high population nano-size oxide particle dispersion. Both optimization of excess oxygen concentration and control of the F/M duplex structure are promising technique for nano-structure control of 9Cr-ODS steel. Tungsten solid solution strengthening appears to be small compared with oxide dispersion strengthening enhanced by duplex microstructure formation.

The precipitation behavior of oxide particles in mechanically alloyed powder of oxide-dispersion-strengthened steel was studied using chemical extraction method and X-ray diffraction analysis. In particular, the temperature and time dependences of the precipitation behavior of Y–Ti–O oxide particles were investigated. The results suggest more appropriate hot extrusion conditions to finely disperse oxide particles, to improve, and to guarantee the creep property of oxide-dispersion-strengthened steel.

9Cr-ODS (oxide dispersion strengthened) steels developed by JAEA (Japan Atomic Energy Agency) have superior creep properties compared with conventional heat resistant steels. The ODS steels can enormously contribute to practical applications of fast breeder reactors and more attractive fusion reactors. Key issues are developments of material processing procedures for mass production and creep life prediction methods in present R&D. In this study, formulation of creep constitutive equation was performed against the backdrop. The 9Cr-ODS steel displaying an excellent creep property is a dual phase steel. The ODS steel is strengthened by the δ ferrite which has a finer dispersion of oxide particles and shows a higher hardness than the α′ martensite. The δ ferrite functions as a reinforcement in the dual phase 9Cr-ODS steel. Its creep behavior is very unique and cannot be interpreted by conventional theories of heat resistant steels. Alternative qualitative model of creep mechanism was formulated at the start of this study using the results of microstructural observations. Based on the alternative creep mechanism model, a novel creep constitutive equation was formulated using the exponential type creep equation extended by a law of mixture.

Strain-controlled low cycle fatigue tests were conduced for 9Cr–ODS and 12Cr–ODS steels at 873, 923, 973 and 1023 K. The total strain ranges were controlled from 0.5% to 1.5% with strain rate of 0.1%/s. Corresponding plastic strain ranged from 0.01% to 1%. The ODS steels exhibit relatively low level of plastic strain and thus have longer fatigue life in the low total strain region compared to conventional ferritic steels such as Mod. 9Cr–1Mo steel. Neither noticeable cyclic hardening nor softening was observed in ODS steels, whilst Mod. 9Cr–1Mo steel shows an apparent cyclic softening at 873 and 923 K. This is attributable to the excellent microstructure stability due to the presence of nano-sized oxide particles dispersed in ODS steels.

The mechanisms of irradiation embrittlement of two Japanese RAFSs were different from each other. The larger DBTT shift observed in F82H is interpreted by means of both hardening effects and a reduction of cleavage fracture stress by M23C6 carbides precipitation along lath block and packet boundaries, while that of JLF-1 is due to only the hardening effect. Dimensional change measurement during in-pile creep tests revealed the creep strain of F82H was limited at 300 °C. Performance of the weld bond under neutron irradiation will be critical to determine the life time of blanket structural components. Application of the ODS steels, which are resistant to corrosion in supercritical pressurized water, to the water-cooled blanket is essential to increase thermal efficiency of the blanket systems beyond DEMO. The coupling of RAFS and ODS steel could be effective to realize a highly efficient fusion blanket.

The superior creep properties of 9Cr ODS (Oxide Dispersion Strengthened) steels result from small oxide particles dispersed in the matrix. Thus many investigations have studied the creep properties by focusing on the oxide particle distribution, but these results are not sufficient to clarify the creep mechanism and to develop material processing procedures for mass production. Potential microstructural features affecting the creep properties should be studied. The 9Cr ODS steel has many potential microstructural features, for example, PPB (Prior Particle Boundary) pores, precipitates, and two matrix phases. In particular, PPB pores link up and develop into large creep cavities. Therefore, particle size classification of mechanically alloying (MA) produced powders was performed to control PPB. Contrary to our expectations, the particle size classification did not only affect PPB creep cavities, but also other microstructural features. MA powder particle size effects on microstructural features and the creep properties were studied.

Embryonic stem (ES) cells are self-renewing cells that maintain pluripotency to differentiate into all types of cells. Because of their potential to provide a variety of tissues for use in regenerative medicine, there is great interest in the identification of growth factors that govern these unique properties of ES cells. However, the signaling pathways controlling ES cell proliferation remain largely unknown. Since transforming growth factor β (TGFβ) superfamily members have been implicated in the processes of early embryogenesis, we investigated their roles in ES cell self-renewal. Inhibition of activin-Nodal-TGFβ signaling by Smad7 or SB-431542 dramatically decreased ES cell proliferation without decreasing ES pluripotency. By contrast, inhibition of bone morphogenetic protein (BMP) signaling by Smad6 did not exhibit such effects, suggesting that activin-Nodal-TGFβ signaling, but not BMP signaling, is indispensable for ES cell propagation. In serum-free culture, supplementation of recombinant activin or Nodal, but not TGFβ or BMP, significantly enhanced ES cell propagation without affecting pluripotency. We also found that activin-Nodal signaling was constitutively activated in an autocrine fashion in serum-free cultured ES cells, and that inhibition of such endogenous signaling by SB-431542 decreased ES cell propagation in serum-free conditions. These findings suggest that endogenously activated autocrine loops of activin-Nodal signaling promote ES cell self-renewal.

For understanding the microstructual details of nano-size oxide particles, three types of ODS ferritic and austenitic steels were examined by high voltage electron microscopy, EDS and AP-FIM. The oxide included Y, Ti and O and showed a shell-like structure with different composition. The shell-like structure depends on crystal structure of the matrix during fabrication process. To evaluate the irradiation stability of the oxide particles, the electron irradiation was carried out to 47 dpa in the temperature range between room temperature and 923 K. During the irradiation, the oxide particles did not show obvious change in size. The irradiation behavior is discussed comparing with the results recently reported.

Zinc finger and SCAN domain-containing 10 (Zscan10, also known as Zfp206) encodes a transcription factor that has been reported to be involved in the maintenance of pluripotency in mouse embryonic stem (ES) cells. Here we generated inducible knockout ES cells for Zscan10 using the Cre-loxP system and analyzed its function. We succeeded in establishing Zscan10-null ES cells and confirmed their pluripotency by the generation of chimeric embryos. Our results clearly indicate that Zscan10 is dispensable for the ability of self-renewal and differentiation in ES cells.

We have developed Body-Braille as an information transmission support tool for Deaf-Blind people. In this paper, improving the readability of Body-Braille is the goal. We investigated the optimal characteristics through two experiments. One is the reading of Body-Braille when produced by three types of motors, which are different in amplitude and frequency. The other is the reading of Body-Braille while changing the frequency with a fixed amplitude. As a result of the experiments, we revealed that the readability was influenced by both amplitude and frequency of the vibrator. Moreover we found that the optimal frequency band of the vibrator was in the range of 70Hz to 100Hz.

Nuclear receptor subfamily 0, group B, member 1 (Nr0b1, also known as Dax1) is regarded as an important component of the transcription factor network that governs pluripotency in mouse embryonic stem (ES) cells. Here we generated inducible knockout ES cells for Nr0b1 using the Cre-loxP system and analyzed its precise function. We succeeded in establishing the Nr0b1-null ES cells and confirmed their pluripotency by showing their contribution to chimeric embryos. However, they proliferated slowly with over-expression of 2-cell stage specific transcripts including Zscan4c, which is known to be involved in telomere elongation in ES cells. We revealed that over-expression of Zscan4c prevents normal self-renewal by inducing arrest at G2 phase followed by cell death and that Nr0b1 directly represses the Zscan4c promoter. These data indicated that Nr0b1 is not essential to maintain pluripotency but is involved in the proper activation of 2-cell specific transcripts for self-renewal.

The requirement of leukemia inhibitory factor (LIF) for the establishment and maintenance of mouse embryonic stem cells (ESCs) depends on the genetic background of the ESC origin. To reveal the molecular basis of the strain-dependent function of LIF, we compared the activation of the intracellular signaling pathways downstream of LIF in ESCs with different genetic backgrounds. We found that the JAK-Stat3 pathway was dominantly activated in ESCs derived from ‘permissive’ mouse strains (129Sv and C57BL6), whereas the MAP kinase pathway was hyperactivated in ESCs from ‘non-permissive’ strains (NOD, CBA and FVB). Artificial activation of Stat3 supported stable self-renewal of ESCs from non-permissive strains. These data suggest that the difference in the balance between the two intracellular signaling pathways underlies the differential response to LIF., Highlighted article: Different mouse strains show distinct JAK-Stat and MAPK activity responses to LIF treatment, accounting for the varying ease of generating stem cells from these lines.

Effects of varying oxygen concentration and final heat treatment on high-temperature strength and microstructure in 9Cr-oxide dispersion strengthened steel (9CrODS) were investigated. It was shown that appropriate control of excess oxygen concentration remarkably improves creep strength of 9CrODS. This creep strength improvement is ascribed to ultra-fine oxide particle dispersion in a part of the grains and increasing austenite (γ) to ferrite (α) diffusional transformation. Enhancement of austenite (γ) to ferrite (α) diffusional transformation leads to suppression of grain boundary sliding. Creep strength of 9CrODS can be remarkably improved by controlling excess oxygen concentration and performing a furnace-cooling heat treatment for austenite (γ) to ferrite (α) diffusional transformation.

9Cr-ODS (oxide dispersion strengthened) steels are being developed for structural materials of fast breeder reactors and fusion reactors. The steels can be characterized by small Y–Ti–O complex oxide particles dispersed in the matrix. Thus, many researches have studied creep properties by focusing on oxide particles and dislocations with transmission electron microscopy (TEM) observations, but such studies are still insufficient to clarify the creep mechanism. In this work, a potential microstructural feature affecting creep properties, prior particle boundary (PPB) cavities formed during creep and aligned along the extrusion direction, was studied. Field emission gun-scanning electron microscopy (FE-SEM) observations on the crept specimens indicated PPB cavities enhanced creep crack propagation. The effect of PPB cavities on creep properties were quantitatively studied by consolidating two different sizes mechanical alloying (MA) powders (>90 and

New type of remote support system for handicapped persons is proposed in this paper. Body-Braille system is consisted of six small vibrators which have been used in cellular phones. And this system is put on the any part of human body. Supports method are similar to usual Braille, and the impaired persons acquire the communication or information about circumferences by reading the vibration patterns on the skin which are consisted of six on-off vibrations of small motors. This paper has shown the remote support system and experiment in which Body-Braille system and cellular phone are connected to realize its functions. The deaf-blind persons have cellular phone with small camera, and remote supporter can get the necessary information by receiving images from the phone, and then send recognition result to subject using Body-Braille. From the results of the experiment, proposed support system has been clarified to be effective.

When a ferritic-martensitic stainless steel (PNC-FMS) wrapper tube having far greater swelling resistance against neutron irradiation is applied in the JOYO or MONJU reactor, it becomes necessary to weld it with SUS316 austenitic stainless steel (entrance nozzle and handling head). Such welding between PNC-FMS and SUS316 causes the delta (δ) ferrite formation at heat-affected zone, which leads to significant toughness degradation. In addition, bending of wrapper tube caused by their differential thermal expansion should be straightened. For preventing those problems, manufacturing process of the complex wrapper tube was developed. This process involves TIG-welding with SUS316 short pipe joints in 50mm length to both ends of a PNC-FMS round tube, and then performing the drawing and normalizing and tempering. Normalizing induces complete disappearance of the δ ferrite in the course of wrapper tube manufacturing. The mechanical properties of PNC-FMS/SUS316 welded zone were confirmed to be equivalent to those...

The effects of chemical compositions (titanium, oxygen) and consolidation temperature on high-temperature mechanical properties of 9Croxide dispersion strengthened steel (9CrODS steel) were investigated. A possible high-temperature strengthening mechanism of 9CrODS steel was discussed based on the experimental results. Creep strength of 9CrODS steel at 973 K was remarkably improved when titanium concentration was 0.35 mass%. A higher amount of added titanium than 0.2 mass% was effective for providing consistently reliable manufacturing of high strength 9CrODS steel because it reduced the effect of oxygen contamination on high-temperature strength. The fraction of elongated � -ferrite grains, which had an ultra-fine oxide particle dispersion, tended to increase with increasing titanium. The elongated grains were considered to improve creep strength of 9CrODS steel. It was also found that creep strength was degraded by elevating the consolidation temperature from 1423 K to 1473 K.

The 12Cr-oxide dispersion strengthened (ODS) ferritic steel is being developed as prospective cladding materials for attaining higher burnup and higher coolant outlet temperature in advanced fast reactor. Ductility and high temperature strength in the hoop direction can be attained by recrystallization in the manufactured tube of 12Cr-ODS ferritic steels. In this study, it was found that once recrystallization has taken place during manufacturing process with four passes cold rolling and intermediate heat treatment, the recrystallized condition can not be repeated at the final heat treatment. Thus, the unique two-step softening heat treatment was developed as the intermediate heat treatment; the first step heat treatment relieves the strain energy accumulated by cold rolling to raise the recrystallization temperature, and the subsequent second step heat treatment at the temperature, which is higher than the recrystallization temperature before relieving the work strain energy, accelerates the hardness red...

The effects of different percentages of oxygen and titanium on the mechanical properties and microstructure of 9Cr-ODS steel were investigated. It was shown that the high-temperature strength was drastically improved by controlling the atomic ratio between excess oxygen and titanium (x in TiOx) around 1.0. When x is around 1.0, the elongated alpha-grains containing the ultra-fine and close oxide particle dispersion were generated in addition to equiaxed martensite grains. Furthermore, the number density of oxide particle in the martensite grains increased. The control of phase transformation and oxide particle dispersion by adjusting oxygen and titanium contents should be a key technology to achieve superior high-temperature strength.

The effects of fast neutron irradiation on ring-tensile properties of the oxide dispersion strengthened (ODS) ferritic/martensitic steel claddings with improved microstructural isotropy from recrystallization and α–γ phase transformation were investigated. The samples were irradiated in the experimental fast reactor JOYO using the material irradiation rig at temperatures between 670 and 807 K to fast neutron fluences ranging from 5.0 × 1025 to 3.0 × 1026 n/m2 (E>0.1 MeV). The post-irradiation ring-tensile tests were carried out on samples with five sets of irradiation conditions. The experimental results showed that strengths were increased by 10% due to irradiation. Microstructural improvement considerably increased elongations for these samples and specimens retained respectable elongation after irradiation. The ring-tensile properties of these ODS steel claddings remain excellent within the fluence level achieved in this study.

Oxide-dispersion-strengthened (ODS) ferritic steel incorporating nanoscale oxide particles was produced by mechanical alloying, and the complex oxide particles, comprised of titanium and yttrium, characterized by high-resolution transmission electron microscopy (HRTEM) and characteristic X-ray nano-analyses. The interface between the ferritic matrix and the major Ti-Y complex oxide was incoherent. From HRTEM and characteristic X-ray nano-analyses, plus the extremely limited literature data on ODS ferritic steels, it was determined that the most stable complex oxide was cubic Y2Ti2O7, which formed by a spontaneous reaction between nano-sized ceramics with a low solubility limit in the metal.

Self-renewal and differentiation of embryonic stem (ES) cells are controlled by the combinatorial action of extracellular signals and regulation of gene expression. For characterizing the entire molecular mechanism governing these events, we first established a feeder- and serum-free culture system in which mouse ES cells could propagate in clonal density in keeping with proper pluripotency. Supplementation of peptide hormones such as adrenocorticotropic hormone (ACTH) is required to remove serum, and the key event in this phenomenon may be the inhibition of the adenylyl cyclase (AC) activity, as it replaces the effect of these peptides. Because ES cells themselves produce the same activity, the finding suggests a novel mechanism in which activation of AC restricts clonal propagation of pluripotent stem cells.

Effects of fin height and helix angle on condensation inside a herringbone microfin tube have been experimentally investigated with five types of herringbone microfin tubes. Heat transfer coefficients are about 2–4 times higher than that of the helical microfin tube under high mass velocity conditions. In the low mass velocity, they are equal to that of the helical microfin tube. The heat transfer enhancement increases with fin height up to 0.18 mm; higher fin heights show enhancement values similar to the 0.18 mm results. Pressure drop increases with the fin height. Larger helix angle yields higher heat transfer and higher pressure drop. For the lowest fin and/or smallest helix angle, the pressure drop is comparable with that of the helical microfin tube, while the heat transfer enhancement is higher. The enhancement mechanism is discussed from flow pattern observations. Effect of mass transfer resistance for R410A is estimated and negligible effects have been proved.

An asthmatic patient with corticosteroid treatment for 45 years presented with slowly progressive limb muscle atrophy. His muscle symptoms were involved in four limbs and tongue, and deep tendon reflexes were exaggerated. Biopsied muscle pathology indicated the presence of neurogenic muscular atrophy in combination with corticosteroid myopathy. Furthermore, 8-hydroxy-deoxyguanosine (8-OH-dG) was prominently increased in mitochondrial and nuclear DNA. An aerobic exercise test demonstrated remarkable serum lactate elevation, which was attenuated by the administration of coenzyme Q10- These findings are consistent with the assumption that long-term corticosteroid administration potentially induces not only myopathy but also motor neuron involvement as in mitochondrial diseases.(Internal Medicine 42: 862-866, 2003)

A detailed investigation has been carried out into the evolution of grain size and grain orientation in electroplated Cu interconnection lines. The specimens were annealed to produce a range of different grain size distributions. Very accurate grain size distributions were obtained from extensive TEM observations of a large number of specimens, followed by computer tracing of grain boundaries. Although annealing causes the average grain size to increase, very small grains are found to persist in the distribution, even when the average grain size is large. These small grains have been investigated in detail to determine the reason for their thermal stability. In addition, the occurrence and redistribution of small micro-voids has been investigated for wafers with different grain sizes. These voids are believed to be associated with seams which are formed in the Cu lines during plating.

We have been developing the Body-Braille system, which transmits Braille characters to disabled people through vibrations on any part of the body. Five years ago, we began working on music applications of this. Using 9 micro vibrators, any melody with a sound range less than 2 octaves can be expressed by vibration. Last year, we developed the music presentation system using only two vibrators. Using special equipment (Pocket-Body braille, Pocket-Bbrll), we performed two experiments and obtained successful results for applying a small number of vibrations to music expression. The details of the system to present music tone by vibration and the results of the experiment are described.

Recent progress of the 9CrODS steel development is presented focusing on their microstructure control to improve sufficient high-temperature strength as well as cladding manufacturing capability. The martensitic 9CrODS steel is primarily candidate cladding materials for the Generation IV fast reactor fuel. They are the attractive composite-like materials consisting of the hard residual ferrite and soft tempered martensite, which are able to be easily controlled by α-γ phase transformation. The residual ferrite containing extremely nanosized oxide particles leads to significantly improved creep rupture strength in 9CrODS cladding. The creep strength stability at extended time of 60,000 h at 700 oC is ascribed to the stable nanosized oxide particles. It was also reviewed that 9CrODS steel has well irradiation stability and fuel pin irradiation test was conducted up to 12 at% burnup and 51 dpa at the cladding temperature of 700oC.

We have been studying the Body-Braille system that transmits Braille characters to disabled people through vibrations on any part of the body. Two years ago, we began to use a SMA (Shape Memory Alloy) device instead of a micro-vibrator. As a result, several advantages were obtained such as smaller equipment size, high resolution transmission, and low power consumption. This year, we developed test equipment for the SMA device which can supply flexible PWM (Pulse Width Modulation) parameters and performed several tests for Braille reading. The test results reveal several possibilities for using a SMA device as a communication channel.

Mutations of the adenomatous polyposis coli gene (APC) have been implicated in the occurrence of sporadic colon cancer. Various APC mutant strains of mice have been created to better understand the function of this gene. Previously, we had mice express a mutant form of mRNA of the APC protein that encoded 474 amino acids instead of the 2845 amino acids due to exon duplication. These APC mutant mice (APC delta 474) developed intestinal and mammary tumors, as have other APC mutant mice previously reported (Sasai, H., et al. Carcinogenesis, in press). To elucidate the mechanism of the tumor development, we prepared protein samples from both normal and tumor tissues from APC delta 474 mutant mice, as well as tissues from normal mice, and used them for proteomic analysis. After two-dimensional electrophoresis, the gels were silver stained and the protein spots were analyzed. We analyzed about 1000 protein spots per sample and found several protein spots that are specific for normal or tumor samples from APC delta 474 mutant mice, as well as proteins with altered expression levels. Among the identified protein spots, truncated beta-tubulins were specific to APC delta 474 mutant mice polyp samples. The apparent molecular mass of these proteins suggested that these beta-tubulins may be truncated very close to the binding site of the anti-tumor drug taxol.

The N-terminus of MDM2 proto-oncoprotein interacts with p53 and down modulates p53 activity by inhibiting transcriptional activity and promoting p53 degradation. MDMX is structurally related to MDM2 and also binds to p53. However, the function of MDMX has not been clarified yet. We found that MDM2 hetero-oligomerized with MDMX through their C-terminal RING finger domains. Yeast two-hybrid analysis revealed that the hetero-oligomerization between MDMX and MDM2 was more stable than the homo-oligomerization of each protein. MDM2 has been shown to be degraded by the ubiquitin-proteasome pathway, while MDMX was a stable protein. Interaction of MDMX with MDM2 through the C-terminal RING finger domains resulted in inhibiting degradation of MDM2. These data indicate that MDMX functions as a regulator of MDM2.

Tumor suppressor Trp53 works as a guardian of the genome in somatic cells. In mouse embryonic stem (ES) cells, it was reported that Trp53 represses pluripotency-associated transcription factor Nanog to induce differentiation. However, since Trp53-null mice develop to term, Trp53 is dispensable for both the maintenance and differentiation of the pluripotent stem cell population in vivo, suggesting the differential functions of Trp53 in ES cells and embryos. To reveal the basis of this discrepancy, here we established a new line of Trp53-null ES cells by sequential gene targeting and evaluated their ability to differentiate in vitro and in vivo. We found that Trp53-null ES cells had defects in differentiation in vitro as reported previously, whereas they were able to contribute to normal development in chimeric embryos. These data indicated that the requirement of Trp53 for maintaining and executing the ES pluripotency is not absolute.

The oxide dispersion strengthened (ODS) ferritic steels are expected as the structural materials for the advanced fusion reactors due to superior radiation resistance and high-temperature strength. Mechanically alloyed powders were consolidated by hot-extrusion and formed by hot-forging. Three types of ODS steels were manufactured: 9CrODS containing 16 % and zero % of the residual ferrite and 12CrODS containing 41 % of residual ferrite. Miniaturized specimens were prepared in the longitudinal direction parallel to finely elongated residual ferrite. The upper shelf absorbed energies (USE) vary in 41 J, 94 J and 134 J in full-size, which increase with increasing a residual ferrite fraction. Higher USE is attributed to larger crack propagation energy, which is induced by different fracture modes in the residual ferrite and tempered martensite.

Connectin (titin) links the Z line to the myosin filament in sarcomeres of vertebrate skeletal muscle. An 800 kDa fragment of alpha-connectin runs from the Z line up to the N2 line region in the I band, and the following beta-connectin portion runs up to the edge of the M line on the myosin filament in chicken breast muscle sarcomeres. Immunoelectron microscopy showed that a 400 kDa fragment following the 800 kDa fragment reaches the edge of the myosin filament and, thereafter a 1,700 kDa fragment runs to the M line on the myosin filament in chicken breast muscle sarcomeres. When stretched, the epitopes to anti-400 kDa fragment antibodies outside the myosin filament moved toward the inside of the I band.