Quantum conversion and image detection by a bacteriorhodopsin-based artificial photoreceptor     

Miyasaka T  Koyama K  Itoh I 《Science (New York, N.Y.)》1992,255(5042):342-344

A thin film (50 to 500 angstroms thick) comprising fragments of bacteriorhodopsin (bR)-containing purple membrane was formed on an SnO(2) conductive electrode by the Langmuir-Blodgett method. The film was put into contact with a thin, aqueous electrolyte gel to construct an electrochemical sandwich-type photocell with a junction structure SnO(2)/bR/electrolyte/Au electrode. Under visible light irradiation, the bR-based photocell produced an efficient rectified photocurrent that proved to have unique differential responsivity to light intensity, which is characteristic of in vivo biological photoreceptors. An artificial photoreceptor comprising a pixel network of the bR photocell was fabricated in an attempt to study image-detecting and processing abilities of bR.  相似文献   

Spatial patterns in the distribution of tropical tree species   总被引：1，自引：0，他引：1  

Condit R  Ashton PS  Baker P  Bunyavejchewin S  Gunatilleke S  Gunatilleke N  Hubbell SP  Foster RB  Itoh A  LaFrankie JV  Lee HS  Losos E  Manokaran N  Sukumar R  Yamakura T 《Science (New York, N.Y.)》2000,288(5470):1414-1418

Fully mapped tree census plots of large area, 25 to 52 hectares, have now been completed at six different sites in tropical forests, including dry deciduous to wet evergreen forest on two continents. One of the main goals of these plots has been to evaluate spatial patterns in tropical tree populations. Here the degree of aggregation in the distribution of 1768 tree species is examined based on the average density of conspecific trees in circular neighborhoods around each tree. When all individuals larger than 1 centimeter in stem diameter were included, nearly every species was more aggregated than a random distribution. Considering only larger trees (>/= 10 centimeters in diameter), the pattern persisted, with most species being more aggregated than random. Rare species were more aggregated than common species. All six forests were very similar in all the particulars of these results.  相似文献   

Regulation of mammalian tooth cusp patterning by ectodin     

Kassai Y  Munne P  Hotta Y  Penttilä E  Kavanagh K  Ohbayashi N  Takada S  Thesleff I  Jernvall J  Itoh N 《Science (New York, N.Y.)》2005,309(5743):2067-2070

Mammalian tooth crowns have precise functional requirements but cannot be substantially remodeled after eruption. In developing teeth, epithelial signaling centers, the enamel knots, form at future cusp positions and are the first signs of cusp patterns that distinguish species. We report that ectodin, a secreted bone morphogenetic protein (BMP) inhibitor, is expressed as a "negative" image of mouse enamel knots. Furthermore, we show that ectodin-deficient mice have enlarged enamel knots, highly altered cusp patterns, and extra teeth. Unlike in normal teeth, excess BMP accelerates patterning in ectodin-deficient teeth. We propose that ectodin is critical for robust spatial delineation of enamel knots and cusps.  相似文献   

A MODIFICATION OF RIDDLE'S METHOD OF PROLACTIN ASSAY     

Uyei N  Itoh M  Hayatsu S  Uyeno F 《Science (New York, N.Y.)》1940,92(2393):435-436

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Oxygen isotopic compositions of asteroidal materials returned from Itokawa by the Hayabusa mission     

Yurimoto H  Abe K  Abe M  Ebihara M  Fujimura A  Hashiguchi M  Hashizume K  Ireland TR  Itoh S  Katayama J  Kato C  Kawaguchi J  Kawasaki N  Kitajima F  Kobayashi S  Meike T  Mukai T  Nagao K  Nakamura T  Naraoka H  Noguchi T  Okazaki R  Park C  Sakamoto N  Seto Y  Takei M  Tsuchiyama A  Uesugi M  Wakaki S  Yada T  Yamamoto K  Yoshikawa M  Zolensky ME 《Science (New York, N.Y.)》2011,333(6046):1116-1119

Meteorite studies suggest that each solar system object has a unique oxygen isotopic composition. Chondrites, the most primitive of meteorites, have been believed to be derived from asteroids, but oxygen isotopic compositions of asteroids themselves have not been established. We measured, using secondary ion mass spectrometry, oxygen isotopic compositions of rock particles from asteroid 25143 Itokawa returned by the Hayabusa spacecraft. Compositions of the particles are depleted in (16)O relative to terrestrial materials and indicate that Itokawa, an S-type asteroid, is one of the sources of the LL or L group of equilibrated ordinary chondrites. This is a direct oxygen-isotope link between chondrites and their parent asteroid.  相似文献   

Synthesis of morphiceptin (Tyr-Pro-Phe-Pro-NH(2)) by dipeptidyl aminopeptidase IV derived from Aspergillus oryzae     

Ota T  Itoh A  Tachi H  Kudoh K  Watanabe T  Yamamoto Y  Tadokoro T  Maekawa A 《Journal of agricultural and food chemistry》2005,53(15):6112-6116

Morphiceptin (Tyr-Pro-Phe-Pro-NH(2)), tetrapeptide, was synthesized using dipeptidyl aminopeptidase IV (DP IV, EC 3.4.14.5) derived from Aspergillus oryzae RIB 915 as a catalyst. Tyr-Pro-OEt was incubated with Phe-Pro-NH(2) in the presence of DP IV under various conditions of temperature, concentrations of ethylene glycol, pH, reaction time, and others. Morphiceptin was obtained at 40% yield under the optimal reaction conditions: substrate, 4 mM Tyr-Pro-OEt.HCl and 20 mM Phe-Pro-NH(2).HCl; enzyme, DP IV, 0.275 nkat; solvent, 60% ethylene glycol containing 20 mM phosphate buffer at pH 7.0; amine, 4.2 mM diisopropylamine at 4 degrees C for 24 h. Amino group protection was unnecessary for synthesis of morphiceptin by DP IV.  相似文献   

Spontaneous medulloblastoma with myoblasts in a Sprague-Dawley rat     

K Shirota  T Itoh  N Kagiyama 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1986,48(2):409-411

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Helminth parasites of the Japanese monkey, Macaca fuscata fuscata in Ehime Prefecture, Japan     

K Itoh  Y Oku  M Okamoto  M Ohbayashi  Y Kitamura  T Shibahara 《The Japanese journal of veterinary research》1988,36(3-4):235-247

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Differentiation of thermophilic Campylobacter by colony characteristics on MacConkey agar base (Difco)     

C Kaneuchi  K Itoh  R Harasawa  M Ogata 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1988,50(5):1112-1114

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Prevalence of Giardia intestinalis infection in dogs of breeding kennels in Japan   总被引：5，自引：0，他引：5  

Itoh N  Muraoka N  Saeki H  Aoki M  Itagaki T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(7):717-718

Giardia intestinalis antigen in fecal samples was examined in 361 dogs of 14 breeding kennels located at various areas in Japan, using a commercial enzyme-linked immunosorbent assay (ELISA) kit. G. intestinalis antigen was detected in 37.4% of the fecal specimens. All of the 14 breeding kennels were positive for G. intestinalis antigen with the range from 6.7 to 59.3%. The prevalence in puppies (54.5%) was significantly (p < 0.01) higher than that in adults (30.9%). There was no difference in prevalence between males and females, and between the puppies from the mother dogs positive and negative for Giardia antigen. In conclusion, G. intestinalis widely invaded the breeding kennels in Japan.  相似文献