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排序方式: 共有1383条查询结果,搜索用时 15 毫秒
161.
T Yudate K Isaka Y Kosugi M Koshiishi K Shiraishi M Hosaka M Takayama 《Canadian Metallurgical Quarterly》1996,48(3):191-198
Thymidylate synthase plays a central role in the biosynthesis of thymidylate, an essential precursor for DNA biosynthesis. In addition to its role in catalysis and cellular metabolism, it is now appreciated that thymidylate synthase functions as an RNA binding protein. Specifically, thymidylate synthase binds with high affinity to its own mRNA, resulting in translational repression. An extensive series of experiments has been performed to elucidate the molecular elements underlying the interaction between thymidylate synthase and its own mRNA. In addition to characterization of the underlying cis- and trans-acting elements, recent studies have shown that thymidylate synthase has the capacity to bind specifically to other cellular RNA species. While the biological significance of these other RNA/thymidylate synthase interactions remains to be defined, this work suggests a potential role for TS in coordinately regulating several critical aspects of cellular metabolism. 相似文献
162.
XH Pei Y Nakanishi K Takayama F Bai M Kawasaki N Hara 《Canadian Metallurgical Quarterly》1998,16(6):551-558
AIMS: To examine the feasibility of using the human iris in vivo for the assessment of the interaction between tyramine and monoamine oxidase (MAO) inhibitors. To examine the relative roles of the two forms of MAO in terminating the response to sympathomimetic amines in the iris, by comparing the effects of single oral doses of moclobemide, a selective MAO-A inhibitor, and selegiline, a selective MAO-B inhibitor, on mydriatic responses to tyramine. METHODS: Twelve healthy male volunteers participated in three monthly sessions, each associated with ingestion of one capsule (moclobemide 450 mg, selegiline 10 mg, or placebo), according to a double-blind, balanced, cross-over design. Tyramine hydrochloride eye-drops (75 mM, 2 x 10 microl) were instilled three times in the left conjuctival sac at 40 min intervals. Pupil diameter was monitored with a binocular infrared television pupillometer before and for 4.5 h after ingestion of the capsule. The pupillary response to tyramine was expressed as the area under the pupil diameter x time curve (arbitrary units). A blood sample was taken before and 2 h after ingestion of the capsule, for the assay of platelet MAO-B activity, and plasma 3,4-dihydroxyphenylglycol (DHPG) concentration, an index of MAO-A activity. Platelet MAO activity was assayed radiochemically, using [14C]-phenylethylamine as substrate, and plasma DHPG by high performance liquid chromatography (h.p.l.c.). The results were analysed using analysis of variance with repeated measures, followed by Bonferroni's corrected t-test, using a significance criterion of P < 0.05. RESULTS: Both moclobemide and selegiline, compared with placebo, caused significant miosis in the right (untreated) eye. The changes in pupil diameter (mm +/- s.e. mean) from the pretreatment measurement were: placebo -0.09 +/- 0.07, moclobemide -0.52 +/- 0.09, selegiline -0.26 +/- 0.1. The mydriatic response to tyramine was potentiated by moclobemide, compared with the response recorded in the presence of placebo. The responses to tyramine (arbitrary units +/- s.e. mean) were: placebo 77.08 +/- 11.65, moclobemide 140.25 +/- 18.9, selegiline 72.75 +/- 12.35. Both moclobemide and selegiline significantly reduced platelet MAO activity, compared with placebo. The changes in platelet MAO activity (nmol h(-1) mg(-1) protein +/- s.e. mean) from the pretreatment level were: placebo 0.5 +/- 0.62, moclobemide -6.7 +/- 0.66, selegiline -17.7 +/- 0.87. Moclobemide significantly reduced plasma DHPG concentration, compared with placebo. The changes in plasma DHPG concentration (nmol l(-1) +/- s.e. mean) from the pretreatment level were: placebo -0.01 +/- 0.24, moclobemide -4.98 +/- 0.32, selegiline -0.51 +/- 0.26. CONCLUSIONS: The potentiation of tyramine-evoked mydriasis by moclobemide is likely to reflect the inhibition of MAO-A activity in the iris, consistent with the activity of this enzyme in sympathetic nerve terminals. The lack of effect of selegiline on tyramine-evoked mydriasis argues against a role of MAO-B in terminating the effects of sympathomimetic amines in the iris. The effects of the two drugs on platelet MAO activity and plasma DHPG concentration are in agreement with previous reports and consistent with the relative selectivity of moclobemide for MAO-A and of selegiline for MAO-B. The miosis caused by the two MAO inhibitors is likely to be due to a central sympatholytic action of the drugs. 相似文献
163.
Nobuki Takayama 《Journal of Symbolic Computation》1995,20(5-6)
A new algorithm to find recurrence relations of binomial sums and a complexity analysis are given. The algorithm is based on the theory of hypergeometric functions and algorithmic method to get contiguity relations of hyperegeometric functions. 相似文献
164.
H Yamamoto K Watanabe W Takayama S Yamada Y Fujita I Honda S Watanabe O Matsuzaki M Ryu 《Canadian Metallurgical Quarterly》1995,25(6):282-285
Fibrolamellar carcinoma of the liver (FLC), which is very rare in Japan, is reported to be frequently accompanied by lymph node metastasis in Europe and the United States. We describe a 22-year-old man with recurrent FLC in the lymph nodes after undergoing partial hepatectomy. He underwent a second operation for removal of recurrent lymph node tumors in the mediastinum and abdominal cavity one year after initial surgery. However, a third operation became necessary seven months later, because of recurrence in a lymph node in the abdominal cavity. We discuss the management of lymph node metastasis from FLC. 相似文献
165.
166.
Kan Okubo Masakazu Takayama Nobunao Takeuchi 《Electromagnetic Compatibility, IEEE Transactions on》2007,49(1):163-169
To clarify the relationship between earthquakes and electrical phenomena, signals of three parameters were observed continuously at Sennan in Akita Prefecture, Japan: ground acceleration (GAC), earth potential difference (EPD), and electrostatic field in the atmosphere (EFA). A large metal plate was used as an electrostatic antenna to observe EFA variation. For this paper, we used the digital natural observation (D-NOB) method as a signal processing technique and found clear EPD and EFA waveforms during seismic wave propagation. Our observation and examination results show that GAC causes EPD variation. Subsequently, the EPD variation induces EFA variation 相似文献
167.
We calculate the thermal conductivity of solid
3
He in U2D2 phase. In this system, magnons are the dominant heat carriers. The experiment by Feng et al. shows that scattering magnon by some kind of magnetic defects becomes important at low temperature. We suppose the defects are the magnetic plane defects (MPD) which are originated by lattice dislocation and calculate the thermal conductivity with Kapitza Resistance Model (KRM). 相似文献
168.
Iwao Hachiya Tetsuo Koyano Kiyotaka Sato 《Journal of the American Oil Chemists' Society》1989,66(12):1757-1762
Effects of seeding of fat crystals on the crystallization kinetics of cocoa butter and dark chocolate were examined with a
rotational viscometer. The seed crystals employed were cocoa butter, 1,3-distearoyl-2-oleoylglycerol (SOS), 1,3-dibehenoyl-2-oleoylglycerol
(BOB) and 1,2,3-tristearoylglycerol (SSS). The seed powders were prepared by pulverization below —50°C, the dimensions being
in a range from 20–70 μm. Particular attention was paid to the influence of polymorphism of the seed crystal. We found that
all of the above seed materials accelerated the crystallization, the degree of acceleration being in a following order; SOS
(β
1) > cocoa butter (Form V) > SOS (a mixture ofβ’ andβ
2) > BOB (β
2) > BOB (pseudo-β’) > SSS (β). Precise measurements of the crystallization kinetics showed that the most influential factors in the seeding
effects are the physical properties of the seed materials—above all, thermodynamic stability, and similarity in the crystal
structure to cocoa butter are the most determinative. 相似文献
169.
Electrophoretic deposition (EPD) was used to form ZnO deposits. ZnO with an average particle size of 40 nm was dispersed in water with the addition of an appropriate amount of anionic polyelectrolyte. Uniform and bubble-free ZnO deposits have been obtained via EPD on a zinc anode in an aqueous suspension. The obtained deposits showed good sinterability. 相似文献
170.
Study on explosion characteristics of natural gas and methane in semi-open space for the HTTR hydrogen production system 总被引:1,自引:0,他引:1
Yoshitomo Inaba Tetsuo Nishihara Mark A Groethe Yoshikazu Nitta 《Nuclear Engineering and Design》2004,232(1):111-119
It is important to grasp the explosion characteristics of object gases: natural gas and methane, in order to evaluate the influence of a gas explosion accident in the HTTR hydrogen production system on the reactor. Thus, we carried out explosion experiments of the object gases in semi-open space, and verified a numerical analysis code for the simulation of the explosion accident. It was confirmed that NG–air mixture or methane-air mixture in semi-open space did not result in DDT although 10 g of C-4 explosive was used as an ignition source, and the numerical results agreed relatively with the experimental results. As a result, we could have the prospects for predicting the influence of the explosion accident on the reactor. 相似文献