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排序方式: 共有813条查询结果,搜索用时 250 毫秒
801.
Yamamoto M Sato S Hemmi H Hoshino K Kaisho T Sanjo H Takeuchi O Sugiyama M Okabe M Takeda K Akira S 《Science (New York, N.Y.)》2003,301(5633):640-643
Stimulation of Toll-like receptors (TLRs) triggers activation of a common MyD88-dependent signaling pathway as well as a MyD88-independent pathway that is unique to TLR3 and TLR4 signaling pathways leading to interferon (IFN)-beta production. Here we disrupted the gene encoding a Toll/IL-1 receptor (TIR) domain-containing adaptor, TRIF. TRIF-deficient mice were defective in both TLR3- and TLR4-mediated expression of IFN-beta and activation of IRF-3. Furthermore, inflammatory cytokine production in response to the TLR4 ligand, but not to other TLR ligands, was severely impaired in TRIF-deficient macrophages. Mice deficient in both MyD88 and TRIF showed complete loss of nuclear factor kappa B activation in response to TLR4 stimulation. These findings demonstrate that TRIF is essential for TLR3- and TLR4-mediated signaling pathways facilitating mammalian antiviral host defense. 相似文献
802.
803.
观察了KT-30与GA_3处理对美味猕猴桃座果、果实发育和品质形成的影响。开花期分别用KT-3040mg·L~(-1)和GA_3500mg·L~(-1)处理花蕾可诱导单性结实;花后20d用KT-3010mg·L~(-1)处理幼果可明显促进果实生长、提高果实中淀粉和糖含量,但降低果实硬度和钙含量且果实外观品质较差。开花后2周用KT-305mg·L~(-1)与GA_3200mg·L~(-1)的混合液处理幼果,可促进果实生长,提高果实硬度,不降低果实外观品质,处理效果最佳。 相似文献
804.
Kenji?SuzukiEmail author Akira?Goto Masakazu?Mizutani Vichai?Sriboonlue 《Paddy and Water Environment》2003,1(2):91-97
In northeast Thailand, the rapid expansion of rainfed paddy fields has decreased the stability of rice production. This paper describes a model that computes rice production on the basis of the hydrologic conditions of rainfed paddy fields on hill slopes. The model well expressed the hydrologic processes, rice yield, and production at the study site. We simulated rice production as uphill paddy plots are abandoned, increasing catchment area, under various rainfall conditions. The simulation showed that rice yield and stability increase as uphill plots are abandoned, although the total rice production decreases. Thus, the effect of catchment size on rice production in each plot was quantified. The model proved to be useful for analyzing rainfed rice production under various land and water conditions. 相似文献
805.
de Ocampo Marjorie P. Ho Viet The Thomson Michael J. Mitsuya Shiro Yamauchi Akira Ismail Abdelbagi M. 《Euphytica》2022,218(9):1-14
Euphytica - The color of flour and its end-use products is an important quality trait of wheat. Understanding the genetic basis of this trait is essential for improving wheat quality. In this... 相似文献
806.
Taoda T Hara Y Takekoshi S Itoh J Teramoto A Osamura RY Tagawa M 《American journal of veterinary research》2006,67(8):1385-1394
OBJECTIVE: To evaluate the effects of mitotane administration on the function and morphology of pituitary corticotrophs in clinically normal dogs. ANIMALS: 12 clinically normal adult Beagles. PROCEDURES: Dogs were randomly assigned to the control group or the mitotane treatment group. In mitotane treatment group dogs, mitotane was administered for 1 month. In both groups, ACTH stimulation testing and corticotrophin-releasing hormone (CRH) stimulation testing were performed. Magnetic resonance imaging (MRI) of the pituitary gland and brain was performed in mitotane treatment group dogs before and after administration of mitotane. After CRH stimulation testing and MRI, dogs were euthanatized and the pituitary gland and adrenal glands were excised for gross and histologic examination. RESULTS: ACTH concentrations in mitotane treatment group dogs were significantly higher than in the control group dogs following CRH stimulation. Magnetic resonance imaging revealed that pituitary glands were significantly larger in treatment group dogs after administration of mitotane, compared with before administration. On gross and histologic examinations, the adrenal cortex was markedly atrophied. Immunohistochemistry revealed hypertrophy of corticotrophs in pituitary glands of mitotane treatment group dogs. CONCLUSIONS AND CLINICAL RELEVANCE: These findings indicate that inhibition of the adrenal cortex by continuous administration of mitotane leads to functional amplification and morphologic enhancement of corticotrophs in clinically normal dogs. In instances of corticotroph adenoma, hypertrophy of individual corticotrophs induced by mitotane may greatly facilitate enlargement of the pituitary gland and increases in ACTH secretion. 相似文献
807.
Zolensky ME Zega TJ Yano H Wirick S Westphal AJ Weisberg MK Weber I Warren JL Velbel MA Tsuchiyama A Tsou P Toppani A Tomioka N Tomeoka K Teslich N Taheri M Susini J Stroud R Stephan T Stadermann FJ Snead CJ Simon SB Simionovici A See TH Robert F Rietmeijer FJ Rao W Perronnet MC Papanastassiou DA Okudaira K Ohsumi K Ohnishi I Nakamura-Messenger K Nakamura T Mostefaoui S Mikouchi T Meibom A Matrajt G Marcus MA Leroux H Lemelle L Le L Lanzirotti A Langenhorst F Krot AN Keller LP Kearsley AT 《Science (New York, N.Y.)》2006,314(5806):1735-1739
The bulk of the comet 81P/Wild 2 (hereafter Wild 2) samples returned to Earth by the Stardust spacecraft appear to be weakly constructed mixtures of nanometer-scale grains, with occasional much larger (over 1 micrometer) ferromagnesian silicates, Fe-Ni sulfides, Fe-Ni metal, and accessory phases. The very wide range of olivine and low-Ca pyroxene compositions in comet Wild 2 requires a wide range of formation conditions, probably reflecting very different formation locations in the protoplanetary disk. The restricted compositional ranges of Fe-Ni sulfides, the wide range for silicates, and the absence of hydrous phases indicate that comet Wild 2 experienced little or no aqueous alteration. Less abundant Wild 2 materials include a refractory particle, whose presence appears to require radial transport in the early protoplanetary disk. 相似文献
808.
Demura H Kobayashi S Nemoto E Matsumoto N Furuya M Yukishita A Muranaka N Morita H Shirakawa K Maruya M Ohyama H Uo M Kubota T Hashimoto T Kawaguchi J Fujiwara A Saito J Sasaki S Miyamoto H Hirata N 《Science (New York, N.Y.)》2006,312(5778):1347-1349
The locations of the pole and rotation axis of asteroid 25143 Itokawa were derived from Asteroid Multiband Imaging Camera data on the Hayabusa spacecraft. The retrograde pole orientation had a right ascension of 90.53 degrees and a declination of -66.30 degrees (52000 equinox) or equivalently 128.5 degrees and -89.66 degrees in ecliptic coordinates with a 3.9 degrees margin of error. The surface area is 0.393 square kilometers, the volume is 0.018378 cubic kilometers with a 5% margin of error, and the three axis lengths are 535 meters by 294 meters by 209 meters. The global Itokawa revealed a boomerang-shaped appearance composed of two distinct parts with partly faceted regions and a constricted ring structure. 相似文献
809.
The importance of demographic niches to tree diversity 总被引:1,自引:0,他引:1
Condit R Ashton P Bunyavejchewin S Dattaraja HS Davies S Esufali S Ewango C Foster R Gunatilleke IA Gunatilleke CV Hall P Harms KE Hart T Hernandez C Hubbell S Itoh A Kiratiprayoon S Lafrankie J de Lao SL Makana JR Noor MN Kassim AR Russo S Sukumar R Samper C Suresh HS Tan S Thomas S Valencia R Vallejo M Villa G Zillio T 《Science (New York, N.Y.)》2006,313(5783):98-101
Most ecological hypotheses about species coexistence hinge on species differences, but quantifying trait differences across species in diverse communities is often unfeasible. We examined the variation of demographic traits using a global tropical forest data set covering 4500 species in 10 large-scale tree inventories. With a hierarchical Bayesian approach, we quantified the distribution of mortality and growth rates of all tree species at each site. This allowed us to test the prediction that demographic differences facilitate species richness, as suggested by the theory that a tradeoff between high growth and high survival allows species to coexist. Contrary to the prediction, the most diverse forests had the least demographic variation. Although demographic differences may foster coexistence, they do not explain any of the 16-fold variation in tree species richness observed across the tropics. 相似文献
810.
Kazumasa Hashimoto Katsumasa Yamada Akira Nagae Yukihiko Matsuyama 《Fisheries Science》2018,84(5):837-848
Taxonomy of the pen shell (genus Atrina) in East Asia has been confused because of the plasticity of the shell morphology and lack of unified morphological characteristics. We analyzed the mitochondrial cytochrome c oxidase subunit I (COI) sequence of the pen shell sampled from Ariake Bay and Seto Inland Sea, western Japan. All individuals were identified as the scaly form based on external morphology; however, their COI sequences were comprised of two distinct lineages. The sequence divergence between the two was 8.3%, indicating the high possibility that they are different species. The scaly form of the pen shell in Japan is one of the target species for resource enhancement, therefore COI lineage identification of broodstock individuals is critically important to avoid producing hybrid seed. We developed a loop-mediated isothermal amplification method that enables specific detection of the two lineages. This method can contribute to reducing the cost and time required for genotyping broodstock individuals prior to seed production. 相似文献