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排序方式: 共有405条查询结果,搜索用时 15 毫秒
201.
202.
K Uegaki S Murase N Nemoto Y Kobayashi S Yoshikawa N Yumoto 《Canadian Metallurgical Quarterly》1997,241(3):737-743
To determine whether or not the dimeric structure of neuropeptide Y (NPY) that is found in solution is necessary for its function, we investigated the effects of covalent dimerization on the structure and function of NPY using the carboxy-terminal fragment, NPY(12-36), in which residues 12 and 31 (located at both ends of alpha-helical region) were replaced by Cys residues. Among the three species (the parallel dimer, the anti-parallel dimer, and the intramolecularly cross-linked monomer) obtained by oxidation of the fragment, the anti-parallel dimer was predominant. NMR analysis showed that both parallel and anti-parallel dimers had alpha-helices similar to that of intact NPY, suggesting that covalent dimerization might have little effect on the helical structure. A binding assay with Y2 receptors on porcine hippocampal membranes revealed that the IC50 value of the anti-parallel dimer was almost the same as that of NPY (13-36), which is known as a Y2-specific ligand. By contrast, the binding by the parallel dimer was weaker by more than one order of magnitude. Our results suggest that the formation of dimers of NPY is not essential for binding to the receptor. 相似文献
203.
An Al-3% Mg solid solution alloy was subjected to intense plastic deformation, using either equal-channel angular (ECA) pressing or torsion straining, to produce grain sizes in the submicrometer range. Static annealing at elevated temperatures led to grain growth and average grain sizes of up to > 100 μm. As-fabricated and statically annealed specimens were used to determine the variation in microhardness with grain size, and results confirm that the Hall-Petch relationship persists down to at least the finest grain size examined experimentally (90 nm). The results provide no evidence to support the claims of a negative Hall-Petch slope when the average grain size is very small, but there is evidence of a decrease in the slope of the Hall-Petch plot at the very finest grain sizes (< 150 nm); this is attributed to the increased participation of mobile extrinsic dislocations in the boundary regions when taking the hardness measurements. 相似文献
204.
A transmission electron microscope investigation has been performed on the morphology of M23C6 precipitation in L12-ordered Ni3(Al, Cr) containing 0.1–0.5 mol% of carbon. By aging at temperatures around 1073 K after solution annealing at 1423 K, fine octahedral-shaped precipitates of M23C6 bounded by {111} facets appear first on the dislocations and then in the matrix. The shapes of the precipitates are not always equilateral but tetragonal or elongated octahedral ones appear during aging. Planar growth faults were observed in some of the octahedral precipitates. After prolonged aging or by aging at higher temperatures, these shapes of precipitates become unstable. The M23C6 precipitates then adopt a rod-like morphology elongated parallel to the 100 directions and characterized by steps bounded by {111} facets. 相似文献
205.
Jingtao Wang Minoru Furukawa Zenji Horita Minoru Nemoto Yan Ma Terence G. Langdon 《Metallurgical and Materials Transactions A》1995,26(3):581-587
Experiments were conducted to determine the age-hardening behavior of an Al-6061 metal matrix composite reinforced with ∼20
vol pct of A12O3 microspheres and prepared using liquid metallurgy processing. The presence of alumina microspheres increases the dislocation
density in the matrix of the composite in the as-quenched state and, by comparison with the monolithic alloy, this leads to
a significant increase in the yield stress in the as-quenched and unaged condition. From measurements of the 0.2 pct proof
stress, there is no evidence for any significant acceleration in the aging process in the composite material: both materials
attain similar peak-aged conditions after essentially the same aging times. The microstructures of the composite and the monolithic
alloy are similar in the peak-aged condition, with a high density of fine needlelike β″ precipitates and, in the over-aged
condition, with a reasonably homogeneous distribution of the rod-shaped β′ phase. It is proposed that the aging behavior is
better quantified by determining the yield stress rather than by taking hardness measurements. Formerly Visiting Scholar,
Kyushu University, 相似文献
206.
H Li T Miyahara Y Tezuka T Namba N Nemoto S Tonami H Seto T Tada S Kadota 《Canadian Metallurgical Quarterly》1998,21(12):1322-1326
Four water extracts of Kampo formulae (Yi-kkan-sen, Dai-ho-in-gan, Ni-chi-gan, Tsu-kan-gan) were screened for their inhibitory activities on bone resorption induced by parathyroid hormone (PTH) in organ culture using neonatal mouse parietal bones. Among the Kampo formulae, Tsu-kan-gan (TKG) showed the most potent inhibitory activity. We further fractionated the TKG water extract by monitoring the inhibitory activity on bone resorption stimulated by PTH in vitro. The MeOH fraction of the water extract inhibited PTH-stimulated bone resorption, and its inhibitory activity was more potent than those of other fractions. The MeOH fraction was then subjected to Sephadex LH-20 column chromatography to give fractions I, II and III, which were examined for bone resorption activity. Fraction I inhibited PTH-stimulated bone resorption, and its inhibitory activity was more potent than those of the other fractions. Upon oral administration of the three fractions (100 mg/kg/d) to ovariectomized (OVX) mice, fractions I and III prevented the decrease of bone mineral density (BMD) of the lumbar vertebra. Eleven compounds isolated from the MeOH fraction were examined for their inhibitory effect on PTH-stimulated bone resorption. Among them, berberine (1), syringin (3), limonin (4) and mangiferin (10) showed a significant inhibitory effect on bone resorption. In the formation assay of osteoclast-like cells, these compounds decreased the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells (MNCs). The inhibitory effect of TKG on bone resorption may be at least partly due to the inhibitory action of these compounds. 相似文献
207.
The grain size and room-temperature tensile strength of Nb3Sn compound were studied over wide ranges of annealing temperature and time using thin and thick multi-filamentary superconducting composite materials. The strength of Nb3Sn compound in thick specimens was lower than that in thin specimens at any heat treatment. This result was accounted for by the existence of extra-coarse grains in thick specimens. It was found that the strength of Nb3Sn compound is nearly proportional to the inverse square root of the grain size. 相似文献
208.
Nemoto K Miura T Shioji G Tsuboi N 《Hemodialysis international. International Symposium on Home Hemodialysis》2011,15(2):288-292
A standard immunotherapy strategy for metastatic renal cell carcinoma (RCC) in dialysis patients has yet to be established. In this study, we report complete remission of RCC with lung metastases in 2 hemodialysis patients after low‐dose interferon therapy (Sumiferon® 3 × 106 international unit 3 times a week). These results suggest that interferon therapy is important for clear cell RCC with lung metastases in dialysis patients, even in the era of molecular‐targeted therapies. 相似文献
209.
This paper presents an experimental study of the characterstics of a ferromagnetic linear vacuum seal with rotation. This seal was developed with respect to the results obtained from observing the behavior of ferromagnetic fluid with a two-dimensional linear seal model apparatus. 相似文献
210.
S Furuhata N Nemoto S Miyazawa M Otani S Toya T Kameya 《Journal of electron microscopy》1992,41(2):120-122
We compared two procedures in the double labelling immunoelectron microscopic method of hormone-storing cells: one-faced and two-faced procedures. With the two-faced procedure we got convincing results consistent with morphological finding, while we often got false results with the one-faced procedure. By the misleading one-faced procedure, the cell storing any one hormone will be misinterpreted as a multihormone storing cell. Therefore, it is concluded that the two-faced method is safer for the double labelling immunoelectron microscopic study. 相似文献