Frequent Occurrence of Discontinuous Dynamic Recrystallization in Ti-6Al-4V Alloy with α′ Martensite Starting Microstructure

The microstructural conversion mechanism in an α′ martensite starting microstructure during hot deformation (at 973 K (700 °C)-10 s^?1) of the Ti-6Al-4V alloy is studied through detailed microstructural observations, kinetic analysis of deformation in the microstructure, and various theoretical models. After compressing the α′ starting microstructure at 973 K (700 °C)-10 s^?1 and at a height strain of 0.8, it is observed that the α′ starting microstructure with acicular morphology evolved into an ultrafine-grained microstructure with an average grain size of 0.2 μm and a high fraction of high-angle grain boundaries. At the initial stage of deformation, subgrain formation in martensite variants and the formation of new grains with high-angle boundaries at interfaces of martensite variants, and $ \{ 10\bar{1}1\} $ twins are dominant. On increasing the height strain to 0.8, discontinuous dynamic recrystallization (DDRX) along with heterogeneous nucleation and fragmentation of grains with high-angle boundaries becomes dominant. In contrast, in the case of an (α + β) starting microstructure, continuous dynamic recrystallization (CDRX) is dominant throughout the deformation process. Thus, we found that DDRX becomes dominant by changing the starting microstructure from the conventional (α + β) to the acicular α′ martensite one. This behavior of the α′ martensite microstructure is attributed to the considerable number of nucleation sites such as dislocations, interfaces of martensite variants and $ \{ 10\bar{1}1\} $ twins, and the high-speed grain fragmentation along with subgrain formation in the α′ starting microstructure during the initial stage of deformation.     

In situ growth BaTiO3 nanocubes and their superlattice from an aqueous process

Ordered aggregated BaTiO(3) nanocubes with a narrow size distribution were obtained in an aqueous process by using bis(ammonium lactate) titanium dihydroxide (TALH) as Ti source in the presence of oleic acid and tert-butylamine. Kinetics of the formation of BaTiO(3) nanocubes indicated that an in situ growth mechanism was dominant and the superlattice of nanocubes formed in situ through the growth of BaTiO(3) nanoparticles in Ti-based hydrous gel. The size and morphology of nanocubes were controlled by tuning the concentration and molar ratio of surfactants. A novel growth model dependant on the structure of Ti precursor for the formation and morphology control of BaTiO(3) nanocubes and their superlattice was demonstrated.     

Whey protein suppresses the osteoclast-mediated bone resorption and osteoclast cell formation

Effects of whey protein on bone resorption and osteoclastic cell formation were evaluated. In the pre-existed and newly formed osteoclast, in bone resorption methods using an unfractionated bone cell culturing system, whey protein suppressed the area of pits formed by osteoclasts. In the osteoclastic cell formation method using the hemopoietic blast cell culturing system, whey protein also suppressed osteoclastic cell formation. These activities were resistant to heat when the protein was treated at 75-90°C for 10 min. Heat-treated whey protein was first fractionated on a Mono S column, and the active fraction (basic protein fraction) was then applied to Superose 12. The molecular weights of the active components were approximately 23 000 and 10 000 Da, as determined by gel filtration. The inner solution of an everted gut-sac incubated in a solution of intact basic protein (BP), pepsin-digested BP or pepsin/pancreatin-digested BP also suppressed osteoclast-mediated bone resorption. Thus, these active components can possibly be absorbed or transported by the intestines. These results showed that whey protein contains an active component that suppresses osteoclast-mediated bone resorption and osteoclastic cell formation.     

Strain-Dependent Electrical Conduction in the System NiO–CaO

Strain-dependent electrical conduction has been observed in the system NiO–CaO. x NiO·(1 - x )CaO solid solutions are fabricated by a traditional solid-reaction method. When the 0.03NiO·0.97CaO solid solution is annealed at 1000°C, excess NiO is excluded and precipitates on the surface or intergrain layers. When compressive stress is applied to the specimen, the electrical conductivity increases with an increase in the applied stress. The magnitude of the conductivity change exceeds 50% during 15 MPa loading at 800°C. The presence of a precipitated NiO layer over the x NiO (1 - x )CaO phase is suggested to be the origin of the applied stress-dependent electrical conductivity.     

Basic properties of hybrid gas-insulated transmission lines (H-GIL)

The recent trend in electric power consumption shows a steady increase and concentration in large cities and industrial districts. This indicates a strong need for a long-distance and enclosed-type power transmission line with large capacity and high reliability. A hybrid gas-insulated transmission line (H-GIL), which has the combined features of an XLPE cable and a conventional gas-insulated transmission line (GIL), has the potential to be applicable to such use. In the present work, we analyze the required dimension and the current capacity of H-GIL on the basis of insulation and thermal design for various parameters determining the structure. We also report an experimental study on flashover characteristics for a simple electrode model of H-GIL. The results show that the H-GIL can be realized with almost the same sheath diameter and current capacity as a conventional GIL. The experiment has also clarified that the insulation reliability of the H-GIL is much higher than that of a GIL. These properties show that the H-GIL has enough feasibility applicable as a long-distance and reliable transmission line with large capacity especially in urban areas. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 119(3): 27–39, 1997     

Damage-free machining of monocrystalline silicon carbide

Cutting tests of monocrystalline SiC, on the surface of which an amorphous layer was preformed by ion implantation, were performed. Ductile-mode machining was observed at a depth of cut smaller than 60 nm. At a depth of cut larger than 60 nm, cracks were observed on the work surface. However, transmission electron micrographs show that crack propagation was obstructed at the interface between the amorphous and crystalline layers even under brittle-mode machining, and no subsurface damage extended into the crystalline layer. The results suggest that the damage-free machining of monocrystalline SiC is possible by surface modification to an amorphous structure.     

Heterologous Biosynthesis of Fungal Indole Sesquiterpene Sespendole

Indole sesquiterpene sespendole, which has been isolated from the filamentous fungus Pseudobotrytis terrestris FKA‐25, is a specific inhibitor of lipid droplet synthesis in mouse macrophages. The biosynthetic pathway that involves genes encoding six enzymes (spdEMBQHJ) was elucidated through heterologous expression of spd genes in Aspergillus oryzae, biotransformation experiments, and in vitro enzymatic reactions with a recombinant protein, thereby revealing the mechanism underlying the characteristic modification on the indole ring, catalyzed by a set of prenyltransferase (SpdE)/cytochrome P450 (SpdJ) enzymes. Functional analysis of the homologous genes encoding these enzymes involved in the biosynthesis of lolitrem allowed a biosynthetic pathway for the bicyclic ring skeleton fused to the indole ring to be proposed.     

Synthesis and properties of novel fluoroalkyl end‐capped oligomers containing silsesquioxane segments

Fluoroalkyl end‐capped homo‐ and co‐ oligomers containing silsesquioxane segments were prepared by the reactions of fluoroalkanoyl peroxides with the corresponding methacrylate monomer‐bearing silsesquioxane unit (Si‐MMA) and comonomers such as N,N‐dimethylacrylamide (DMAA) and acrylic acid (ACA). These new fluorinated Si‐MMA oligomers were easily soluble in various organic solvents and were able to reduce the surface tension of m‐xylene effectively. The modified poly(methyl methacrylate) [PMMA] and glass surface treated with fluorinated Si‐MMA homo‐oligomers exhibited a strong oleophobicity, although these fluorinated oligomers possess high oleophilic silsesquioxane segments. In contrast, the modified PMMA surface treated with fluorinated Si‐MMA–DMAA cooligomers exhibited a good hydrophilicity with a strong oleophobicity. In a series of fluorinated Si‐MMA oligomers, fluorinated Si‐MMA homo‐oligomers had a relatively high thermal stability. Therefore, these fluoroalkyl end‐capped Si‐MMA oligomers are suggested to have high potential for new functional materials through their unique properties such as a high solubility and surface active properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3486–3493, 2002     

The presenilin 2 loop domain interacts with the mu-calpain C-terminal region

Presenilin 2 (PS2) is a gene responsible for the early-onset familial Alzheimer's disease (AD). PS2 mutations are considered to be closely related to the pathogenesis of AD. We screened for proteins that interact with PS2 to understand its pathological and physiological functions. Using the PS2 loop domain as the bait, the yeast two-hybrid system was used for screening, and mu-calpain was identified as a PS2 binding protein. In COS-1 cells, the interaction of PS2 with mu-calpain was confirmed by immunoprecipitation. These results suggested that PS2 and mu-calpain interact with each other, and might regulate each other's functions.     

A pediatric case of myeloperoxidase-antineutrophil cytoplasmic (ANCA)-related crescentic glomerulonephritis associated with propylthiouracil treatment for Graves' disease

We treated a 13-year-old girl who developed myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA)-related crescentic glomerulonephritis (GN) during propylthiouracil (PTU) treatment for Graves' disease. MPO-ANCA-related crescentic GN during PTU therapy has been described previously in only one recent report of 2 children. We report this case here and describe 15 (13 adult cases) more patients with MPO-ANCA-related GN associated with PTU found in a literature review. The mean age at onset was 41.3 years, and the length of PTU administration ranged from 2 weeks to 6 years (mean 3.5 years). Clinical signs and symptoms were hematuria (100%), proteinuria (100%), arthralgia (7 of 16 cases; 43.8%), fever (4 cases; 20.0%), purpura (2 cases; 12.5%), skin ulcer (1 case; 6.3%) and dyspnea (1 case; 6.3%). These patients were treated with steroid (15 cases; 93.8%), cyclophosphamide (8 cases; 50.0%), steroid pulse therapy (4 cases; 25.0%), or plasma exchange (1 case; 6.3%), or were not treated (1 case; 6.3%). Most patients revealed crescentic GN (15 cases; 93.8%) on renal biopsy, while one exhibited mesangial proliferative GN (6.3%). For 2 of the 16 patients (12.5%) irreversible renal dysfunction persisted and hemodialysis was started. Patients with Graves' disease treated with PTU should be observed carefully by urinalysis and monitoring of the serum creatinine level.