Fracture Toughness of a Crystalline Silicon Carbide Fiber (Tyranno-SA3®)

The fracture toughness of a crystalline silicon carbide fiber, Tyranno-SA^®, was determined by introducing an artificial notch directly into the fiber test specimens using a focused-ion (Ga⁺) beam. The relation between fracture strength and notch size was determined experimentally, while the relation among the notch size, fiber diameter, applied stress at infinity, and stress intensity factor was analyzed by the finite element method. By applying the analyzed result to the experimental results, the fracture toughness of the fiber was determined to be     .     

A rapid speech synthesizing software on a PDA for Japanese with speech impairments

We developed a Japanese-language, rapid synthesizing software application for use on a personal digital assistant. It has an unrestricted vocabulary and can synthesize words and sentences within 3 s. Eight hundred common sentences and words are preregistered. By touching the first character at the head of a preregistered sentence or word from an on-screen Kana (Japanese alphabet) chart, the user can select the sentence or word to be spoken. Characters on the Kana chart can also be input sequentially. Two Japanese subjects with speech impairments rated the device highly for its portability and quick response. Whereas communication previously had to be done by writing or sign language, it was easy for listeners with or without specialized training in communication with persons with speech impairments to understand the output from this device, making conversation easier which, in turn, improved the quality of life and social activity of these persons with speech impairments.     

High-energy photoemission spectroscopy of ferromagnetic Ga1−xMnxN

Here we report investigation of valence band electronic states of ferromagnetic Ga_0.96Mn_0.04N by bulk-sensitive X-ray photoemission, which is realized at high flux X-ray undulator beamline BL29XU of SPring-8, at photon energy of 5.95 keV. We have observed that Mn doping introduces a new structure in the band gap region near the top of the valence band, and also a broader structure in deeper valence band region. Basing upon the first principle calculation, these structures are assigned as Ga 4s originated states, which are raised by hybridization between 3d orbitals of Mn with GaN host orbitals. The present result evidences the second nearest Ga bonds are affected by that Mn–N bond formation, suggesting the long-range interaction of Mn in this host material.     

Structural evolution during mechanical alloying and annealing of a Nb-25at%Al alloy

Mixtures of pure elemental Al and Nb powders of Nb-25at%Al composition was mechanically alloyed, and structural evolution during high energy ball milling has been examined. Al dissolved in Nb from the early stage of the ball milling, and amorphization became noticeable after longer than five hours of milling. However the dissolution of Al in Nb was not completed before the amorphization. No intermetallic phase formed during the mechanical alloying. Before complete amorphization, metastable nitride of Nb_4.62N_2.14 (i.e., -NbN) with hexagonal structure has formed in nanocrystalline size through nitrogen incorporation from ambient environment. The lattice parameter of Nb increased significantly (up to 3.3433 Å after 5 hours of milling) during the milling. Upon annealing above 950 °C, Nb₂Al became the dominant feature with the -NbN, and Nb₃Al did not form from the samples milled at ambient environment. Nb₃Al appeared only from a sample milled at Ar environment. Structural evolution during mechanical alloying of the Nb-Al system is critically dependent the upon milling environment.     

Annealing characteristics of Si doped amorphous silica films by rf sputtering

Si doped amorphous silica films were prepared by rf magnetron sputtering technique. As-deposited films which had relatively low Si dopant were annealed in inert atmosphere, and spectroscopic analyses were performed for as-deposited and all the annealed samples by infrared (IR) absorption, X-ray fluorescence analysis, X-ray photoelectron spectroscopy (XPS) and 29Si magic angle sample spinning nuclear magnetic resonance spectroscopy (29Si MAS-NMR). When the sample was annealed at 800°C, the IR absorption peak located at 1080 cm–1 shifted to slightly higher wave number. On the other hand, the decrease of Si clusters or Si–Si bonds in as-deposited film was deduced from X-ray fluorescence and XPS spectra for the sample annealed at 800°C. These annealing characteristics of the films prepared in this study were discussed based on the random bonding model of SiOx film, and the spectral variations with thermal annealing were interpreted by the rearrangement of Si and O atoms in as-deposited films, rather than the simple clustering of excess Si atoms.     

Anisotropy of Young's modulus and tensile properties in cold rolled α′ martensite Ti–V–Sn alloys

Young's modulus and tensile properties of cold rolled Ti–8 mass% V and (Ti–8 mass% V)–4 mass% Sn alloy plates consisting of α′ martensite were investigated as a function of tensile axis orientation in this work. A single phase of α′ (hcp) martensite is obtained in Ti–8 mass% V and (Ti–8 mass% V)–4 mass% Sn alloys by quenching after solution treatment. By 86% cold rolling, acicular α′ martensite microstructures change into extremely refined dislocation cell-like structure with an average size of 60 nm, accompanied with the development of cold rolling texture in which the basal plane normal is tilted from the plate normal direction (ND) toward transverse direction (TD) at angles of ±49° for Ti–8% V alloy and ±46° for (Ti–8 mass% V)–4 mass% Sn alloy. No apparent anisotropy of Young's modulus (E) is observed for as-quenched Ti–8% V (E = 76–83 GPa) and (Ti–8% V)-4%Sn (E = 69–79 GPa). In contrast, Young's modulus increases with increasing angle from the rolling direction (RD) to TD for cold rolled Ti–8% V (E = 72–94 GPa) and (Ti–8% V)–4%Sn (E = 63–85 GPa). The observed anisotropy of Young's modulus can be reasonably explained in terms of the cold rolling α′ texture.0.2% proof stress and tensile strength are independent of tensile orientation for cold rolled Ti–8% V and (Ti–8% V)–4%Sn alloys. In contrast, larger elongation to fracture is obtained in specimens deviated by 30°, 45° and 60° from RD than by 0°, 75° and 90°. Scanning electron microscopy (SEM) fractographs reveal that quasi-cleavage-like fracture plane appears in 0° specimen of cold rolled Ti–8% V which shows brittle fracture and other specimens of cold rolled Ti–8% V and (Ti–8% V)–4%Sn alloys are fractured accompanied with necking and dimple formation. It is suggested from these results that brittle fracture is related to the activation of limited number of slip system and Sn addition leads to the activation of multiple slip systems.     

Value of MR cholangiopancreatography in evaluating choledochal cysts

OBJECTIVE: The aim of this retrospective study was to clarify whether MR cholangiopancreatography (MRCP) is a suitable replacement for ERCP in evaluation of the choledochal cyst. MATERIALS AND METHODS: Sixteen patients (six adult and 10 pediatric) with choledochal cysts underwent MRCP using a half-Fourier acquisition single-shot turbo spin-echo sequence. Extent of the cyst, defects within the biliary tree, and presence or absence of the anomalous junction of the pancreaticobiliary duct were evaluated. Findings were compared with those of ERCP. RESULTS: MRCP better defined the proximal biliary tree than did ERCP in two patients. Defects within the biliary tree were diagnosed correctly on MRCP in eight patients; however, two defects within the distal common bile duct were missed in pediatric patients. The presence of the anomalous junction of the pancreaticobiliary duct was revealed accurately by MRCP in all adult patients but was revealed accurately in only four of the 10 pediatric patients. CONCLUSION: MRCP appears to offer diagnostic information that is equivalent to that of ERCP for assessment of choledochal cysts in adults. In pediatric patients, MRCP should not replace ERCP; however, MRCP can play an important role as a noninvasive examination and should be considered a first-choice imaging technique for evaluation of choledochal cysts.     

Complete deficiency of glycophorin A in red blood cells from mice with targeted inactivation of the band 3 (AE1) gene

Glycophorin A is the major transmembrane sialoglycoprotein of red blood cells. It has been shown to contribute to the expression of the MN and Wright blood group antigens, to act as a receptor for the malaria parasite Plasmodium falciparum and Sendai virus, and along with the anion transporter, band 3, may contribute to the mechanical properties of the red blood cell membrane. Several lines of evidence suggest a close interaction between glycophorin A and band 3 during their biosynthesis. Recently, we have generated mice where the band 3 expression was completely eliminated by selective inactivation of the AE1 anion exchanger gene, thus allowing us to study the effect of band 3 on the expression of red blood cell membrane proteins. In this report, we show that the band 3 -/- red blood cells contain protein 4.1, adducin, dematin, p55, and glycophorin C. In contrast, the band 3 -/- red blood cells are completely devoid of glycophorin A (GPA), as assessed by Western blot and immunocytochemistry techniques, whereas the polymerase chain reaction (PCR) confirmed the presence of GPA mRNA. Pulse-label and pulse-chase experiments show that GPA is not incorporated in the membrane and is rapidly degraded in the cytoplasm. Based on these findings and other published evidence, we propose that band 3 plays a chaperone-like role, which is necessary for the recruitment of GPA to the red blood cell plasma membrane.     

A drug revolving fund program for rural villages in the Philippines

In 1994, a community-based drug revolving fund program was introduced in 10 pilot villages in the province of Tarlac, Philippines, as a component of a health project by the provincial health office and Japan International Cooperation Agency (JICA). The purpose of the program was to set up a cooperative drug store in each community in order to regularly provide rural residents with essential drugs at affordable prices. The following are the results and findings during the first two years of operation. 1. Collaboration with a local NGO facilitated implementation and management of the program, when socio-cultural consideration was necessary. Stable and prompt procurement of drugs was secured on a contract with a commercial wholesaler in Manila. 2. Out of the 105 kinds of pharmaceuticals that were sold both in the cooperative and commercial drug stores, 83% were less expensive than the average market price, and 51% were discounted more than 25% of the market price. 3. The levy of premiums was introduced to increase the cooperative fund with the consent of each community. The amount was 0.1-0.2% of the average family income. However, regular collection of premiums was difficult due to various reasons. The practice of the sales on credit was common in all pilot villages. 4. While the knowledge of community health workers, who were in charge drug sales, was improved after training sessions on rational drug use, it was not at a sufficient level yet. 5. When assisting a community-oriented health program, an exterior organization should try to encourage the community to generate its own solutions to operational difficulties, based on the socio-cultural context in the community.