Corrosion Behavior of Sialon Ceramics in Supercritical Water

The corrosion behavior of sialon ceramics was investigated in supercritical water at 450°C under 45 MPa for 2–50 h. α-sialon exhibited better corrosion resistance than β-sialon and α/β-sialon. Pitting corrosion with the formation of corrosion products was observed in the case of β-sialon and α/β-sialon. By contrast, the corrosion behavior of α-sialon was characterized by uniform corrosion with the formation of corrosion products. The degree of strength deterioration was strongly dependent on the corrosion morphology. The bending strength of α-sialon after corrosion for 30 h was about 90% of its initial strength, while the strength of β-sialon decreased to 65% of its original strength.     

Expression of IFN-inducible protein-10 in chronic hepatitis

Chemokines such as IFN-inducible protein-10 (IP-10) and JE/monocyte chemotactic protein-1 (MCP-1) are induced in the murine liver in a tissue-specific manner. We examined whether IP-10 and MCP-1 are pathologically involved in chronic hepatitis. Whereas the serum levels of IP-10 and MCP-1 in patients with chronic persistent hepatitis C were elevated compared with those in normal volunteers, both chemokine levels were further significantly higher in patients with the active form (chronic active hepatitis (CAH)). The elevated IP-10 level was not a general phenomenon of inflammation, because it was not seen in patients with rheumatoid arthritis, whereas MCP-1 levels were elevated to the same extent in both patient groups. Better responsiveness to IFN therapy in CAH was related to lesser grades of necroinflammatory activity and was predicted by the lower IP-10 and higher MCP-1 levels. IP-10 levels in patients cured by IFN therapy decreased to the levels in normal volunteers, while the MCP-1 levels only slightly decreased. Serum levels of both chemokines in patients who were not cured remained unchanged after IFN therapy. In situ hybridization analysis of CAH revealed that IP-10 mRNA was expressed mainly in hepatocytes around intralobular focal and periportal piecemeal necrosis, while some MCP-1 mRNA was expressed in some sinusoidal cells. These results suggested that IP-10 plays a specific role in the intralobular accumulation of mononuclear cells and/or the death of hepatocytes in chronic hepatitis.     

A large right coronary artery-left ventricle fistula with mild volume overload on the left ventricle owing to its capacitive action--pulsed Doppler and cineangiographic analyses in a patient

A 54-year-old woman was admitted to our hospital because of a heart murmur without subjective symptoms. Angiography disclosed an enlarged right coronary artery and flow drainage into the left ventricle, ie, a large right coronary artery-left ventricle fistula. Analysis of pulsed Doppler studies and cineangiograms indicated considerable capacitance of this fistula owing to Windkessel action, which attenuated volume overload on the left ventricle. The features in this case suggest that evaluation of fistula hemodynamics is important in determining the overload on the ventricle through the fistula.     

Shape selectivity as a function of pore size in epoxidation of alkenes with supported titanium catalysts

Reactant shape selectivity of supported titanium catalysts for epoxidation of cyclohexene and 2-hexene has an excellent correlation with the pore diameter of the catalysts. With titanosilicate the preference to cis isomer epoxidation is small compared to TiO₂-SiO₂ probably because of the restriction of its diffusion imposed by the zeolite micropore structure.     

Localization of the gene encoding the alpha subunit of human interleukin-5 receptor (IL5RA) to chromosome region 3p24-3p26

The chromosomal location of the human gene for the alpha subunit of interleukin-5 receptor (IL5RA) has been determined. The human IL5RA gene was localized to the short arm of chromosome 3 by Southern blot analysis of DNA from a panel of mouse-human hybrid somatic cell lines. The IL5RA gene has been further localized to human chromosome region 3p24-3p26 by in situ hybridization of a molecularly cloned IL5RA cDNA fragment to metaphase chromosomes. The results suggest that the IL5RA locus is unlinked to other members of the hematopoietic receptor family. Assignment of the IL5RA gene to chromosome 3 at bands p26-p24 raises the possibility that it may be altered by certain nonrandom chromosomal abnormalities arising in human hematopoietic malignancies and solid tumors.     

Proton conduction in Nafion composite membranes filled with mesoporous silica

Studies of proton-conductive polymer membranes are vital for the future development of high-performance polymer electrolyte membrane fuel cells (PEM-FC). In particular, a method for inhibiting the volatility of water in the polymer matrix at high temperatures is a crucial issue, directly related to the operation of PEM-FC system. In this study, we focus on polymer composite membranes, which consist of commercial Nafion and mesoporous silica (MPSi) as novel inorganic additives, and investigate an improvement in the total proton conductivities and the good electrochemical stability at high temperatures. MPSi, which can be synthesized with pore sizes from 1 to 10 nm, has a wide range of potential applications because of its extraordinary properties, such as extremely large surface area, flawless surface condition and well-regulated porous structure. We found that the Nafion composites filled with MPSi have approximately 1.5 times higher proton conductivities (more than 0.1 S cm⁻¹ at 80 °C and 95%RH) than pure Nafion and can display good temperature performance relative to pure Nafion and the particle SiO₂ composite. Moreover, the conductivity of Nafion/sulfonated MPSi was the highest (0.094 S cm⁻¹) at 40 °C and 95%RH. These are probably due to the large surface area of MPSi, which can increase the water adsorption in Nafion matrix.     

Speckle interferometry by using virtual speckle pattern based on Carré algorithm

Dynamic deformation measurement with a large deformation is effectively performed by using virtual speckle patterns. The virtual speckle pattern has been generally produced by using the operation based on Fourier transform. However, it takes a long calculating time to produce a virtual speckle pattern, because the method requires Fourier transform operation at each pixel of CCD. In the proposed method, virtual speckle patterns are produced by Carré algorithm without any operation by Fourier transform. The method is applied to the in-plane deformation measurement in this paper. As the results, it is confirmed that the calculating cost of virtual speckle patterns is improved remarkably, and that the measurement accuracy of the new method is also equal to the ordinary methods. It is also confirmed that the proposed method will expand the use of the speckle interferometry based on virtual speckle pattern technology.     

A global stability analysis for symmetric self-electrooptic effectdevice systems using a potential function method

This paper proposes a novel analytical method for use in symmetric self-electrooptic effect device (S-SEED) systems, called the potential function method, based on a global stability analysis of differential equations for photocurrent in S-SEED circuits. The method provides intuitive views for analyzing the stability of the system, and is useful for tracking the temporal dynamics of S-SEED nonlinear electrical circuits. This paper also describes electro-absorption characteristics of SEED's, especially those based on Wannier Stark localization (WSL). In this type of SEED, the photocurrent versus reverse bias voltage characteristics has multiple peaks and multiple negative differential resistance regions, resulting from Stark ladder transitions due to thin barrier superlattices. Various types of stabilities, including the metastable state, as well as the temporal switching dynamics of WSL-S-SEEDs, can be explained clearly by using this potential function method     

Absorption saturation mechanism in short-period GaAs/AlAs superlattice self-electro-optic effect devices based on Wannier-Stark localization

We have studied absorption saturation characteristics in short-period GaAs/AlAs superlattice self-electro-optic effect devices based on Wannier-Stark localization. The disappearance of negative differential resistances due to absorption saturation was observed under high optical excitation intensities. To understand the mechanism, we measured the time-resolved photocurrent and time-resolved photoluminescence. Results revealed that the absorption saturation is caused by electric field screening originating from the space-charge of remaining holes due to effective mass filtering.