Effect of liquid metal composition and hydrodynamic parameters on cavitation erosion

Cavitation erosion testing machine for low-temperature melting alloy liquid was developed by using a vibratory apparatus. The erosion tests of SUS304 were carried out in three kinds of lead–bismuth and deionized water. We defined a relative temperature as the percentage between freezing and boiling points. At relative temperature at 14 °C, the erosion rate is 10–12 times in various lead–bismuth alloys, and 2–5 times in sodium, as compared with that in deionized water. When SUS304 was exposed to a cavitation in PbBi, the surface was work hardened 20% harder compared with original surface. In deionized water, SUS304 was work hardened by 5%. Therefore, we can conclude that larger collapse pressure can be estimated to act on the specimen surface in lead–bismuth, as compared with that in water.We discussed the effect of hydrodynamic properties on cavitation erosion in a flowing system. It is considered that the erosion rate in sodium is in proportion to 1st to 6th power of flow velocity similarly to that in mercury. The incipient cavitation number is approximately unity irrespective of test liquids. Furthermore, the relation between MDER and cavitation number is expressed as power low of function with an exponent of 2.5.     

Effect of a titanium surface on bone marrow-derived osteoblastic cells in vitro

The initial interaction between a titanium implant and the surrounding cancellous bone tissue was investigated by means of in vitro cultures of bone marrow-derived osteoblastic clone TMS-12 cells. Proliferation of TMS-12 cells cultured on a titanium surface was significantly reduced compared with that of control cells cultured directly on plastic, but alkaline phosphatase activity was the same as control cells. Co-culture of spleen cells with TMS-12 cells in the presence of a 1 alpha,25-dihydroxyvitamin D3 on titanium resulted in significant inhibition of tartrate-resistant acid phosphatase activity compared to control cultures on plastic. More prostaglandin E2 (PGE2) was produced by cells grown on a titanium surface than on plastic tissue-culture plates. On the other hand, mouse calvaria-derived osteogenic MC3T3-E1 cells, known to proliferate well on titanium, released similar amounts of PGE2 on titanium surfaces as on plastic tissue culture plates, indicating additional marked differences between the two osteoblastic cell types in response to a titanium surface. These results suggest that the reaction of bone marrow-derived osteoblastic cells to a titanium surface may fundamentally differ from that of calvaria-derived osteoblastics even though both cells are from bone tissue.     

Molecular structure and expression of ion channels in the heart

Ion channels are essential for the generation and maintenance of the cardiac action potential. The successful cloning of ion channels has shed considerable light into their structure and function. The combination of molecular biological and electrophysiological studies has paved the ground to develop general concepts for understanding properties of these channels, such as gating mechanism, kinetics of activation and inactivation, ion selectivity and pharmacological properties. Recently, several cDNAs encoding cardiac inwardly rectifying K+ channels, including classical inwardly rectifying, G-protein-gated, and ATP-sensitive K+ channels, have been isolated. Identification of these molecular mechanisms may point to novel approaches to the treatment of cardiac arrhythmias. This review focuses on the molecular properties and functional roles of cardiac ion channels.     

Semi-conductive properties of melanization of chromate zinc plates

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SiC microsphere derived from phenolic resin—Ethyl silicate heterogeneous precursors with carbothermic reduction

Heterogeneous precursors for SiC particles were synthesized from viscous phenolic resin and tetraethyl orthosilicate with hastening ethanol removal process in a concentrated state. In the pyrolysis products, spherical carbon domains with diameter of several micrometers were embedded in the SiO₂‐C matrix. After the carbothermic reduction process at 2073 K, SiC‐C spheres were obtained with an SiC yield of ～80%, while the carbon domains acted as templates of the SiC‐C spheres with complete disappearance of the SiO₂‐C matrix area. After the carbon burned out, some of the spheres possessed a hollow structure. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1612–1618, 2004     

Identification and functional analysis of sulfonylurea receptor 1 variants in Japanese patients with NIDDM

The sulfonylurea receptor 1 (SUR1) is an essential regulatory subunit of the beta-cell ATP-sensitive K+ channel (K[ATP]). The possible role of SUR1 gene mutation(s) in the development of NIDDM remains controversial as both a positive association and negative linkage results have been reported. Therefore, we examined the SUR1 gene at the single nucleotide level with single strand conformation polymorphism analysis in 100 Japanese NIDDM patients. We identified a total of five amino acid substitutions and 17 silent mutations by examining all 39 exons of this gene. Two rare novel mutations, D811N in exon 20 and R835C in exon 21, were identified in the first nucleotide-binding fold (NBF), a functionally important region of SUR1, in one patient each, both heterozygotes. To analyze possible functional alterations, we reconstituted the mutant K(ATP) by coexpressing beta-cell inward rectifier (BIR) (Kir 6.2), a channel subunit of K(ATP), and mutant SUR1 in HEK293T and COS-7 cells. As demonstrated by the patch clamp technique and rubidium (Rb+) efflux studies, neither mutation alters the properties of channel activities. Two other rare missense mutations, R275Q in exon 6 and V560M in exon 12, were also identified. The R275Q substitution was not found in 67 control subjects, and V560M was present in three control subjects. Neither of these substitutions appeared to cosegregate with NIDDM in the probands' families. A previously reported S1370A substitution located in the second NBF was also common in the Japanese subjects (allelic frequency 0.37), and was found at an equal frequency in nondiabetic control subjects. In conclusion, SUR1 mutations impairing K(ATP) function do not appear to be major determinants of NIDDM susceptibility in Japanese.     

Analysis of soft breakdown failure with ESD on output buffernMOSFETs and its improvement

The leakage increase of the off-state MOSFETs after an ESD event has been studied for output transistors with the thin gate oxide and LDD structures. Leakage increase called “soft breakdown” has been found at relatively low ESD testing voltages (200-300 V). This soft breakdown is caused by the creation of interface traps due to the snap-back stressing during the ESD event. The creation of interface traps has enhanced the interface trap to band tunneling current at the drain side of the MOSFETs. The improvement of the ESD threshold has also been proposed with an additional arsenic implantation into the n^$ region. It has been confirmed that the arsenic implantation improved the HBM ESD threshold to more than 2000 V     

Pregnancy following thyroid hormone treatment in a patient with amenorrhea-galactorrhea due to primary hypothyroidism

A 32-year-old female with amenorrhea-galactorrhea due to primary hypothyroidism was treated with thyroid hormones, and serum levels of thyrotropin (TSH), prolactin (PRL), triiodothyronine (T3), thyroxin (T4), and T3 resin sponge uptake (RT3U) were measured throughout the course of treatment. The elevated serum levels of TSH and PRL fell into the normal range following T3 treatment. Subsequently, the menstrual cycle was restored within 1 month, and galactorrhea completely ceased and conception was achieved within 3 months. Desiccated thyroid was administered during pregnancy, and the patient gave birth to a female infant. Impaired secretion of PRL during pregnancy and poor milk secretion with blunted response of PRL to the suckling stimulus during the puerperium were noted.