Carbon balance in the life cycle of wood: targeting a timber check dam     

Chihiro Kayo  Ryu Noda  Takanobu Sasaki  Shinya Takaoku 《Journal of Wood Science》2015,61(1):70-80

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Turbulence and magnetic fields in the large-scale structure of the universe     

Ryu D  Kang H  Cho J  Das S 《Science (New York, N.Y.)》2008,320(5878):909-912

The nature and origin of turbulence and magnetic fields in the intergalactic space are important problems that are yet to be understood. We propose a scenario in which turbulent-flow motions are induced via the cascade of the vorticity generated at cosmological shocks during the formation of the large-scale structure. The turbulence in turn amplifies weak seed magnetic fields of any origin. Supercomputer simulations show that the turbulence is subsonic inside clusters and groups of galaxies, whereas it is transonic or mildly supersonic in filaments. Based on a turbulence dynamo model, we then estimated that the average magnetic field strength would be a few microgauss (microG) inside clusters and groups, approximately 0.1 muG around clusters and groups, and approximately 10 nanogauss in filaments. Our model presents a physical mechanism that transfers the gravitational energy to the turbulence and magnetic field energies in the large-scale structure of the universe.  相似文献   

Requirement of CD9 on the egg plasma membrane for fertilization   总被引：1，自引：0，他引：1  

Miyado K  Yamada G  Yamada S  Hasuwa H  Nakamura Y  Ryu F  Suzuki K  Kosai K  Inoue K  Ogura A  Okabe M  Mekada E 《Science (New York, N.Y.)》2000,287(5451):321-324

CD9 is an integral membrane protein associated with integrins and other membrane proteins. Mice lacking CD9 were produced by homologous recombination. Both male and female CD9-/- mice were born healthy and grew normally. However, the litter size from CD9-/- females was less than 2% of that of the wild type. In vitro fertilization experiments indicated that the cause of this infertility was due to the failure of sperm-egg fusion. When sperm were injected into oocytes with assisted microfertilization techniques, however, the fertilized eggs developed to term. These results indicate that CD9 has a crucial role in sperm-egg fusion.  相似文献   

Innate immune homeostasis by the homeobox gene caudal and commensal-gut mutualism in Drosophila     

Ryu JH  Kim SH  Lee HY  Bai JY  Nam YD  Bae JW  Lee DG  Shin SC  Ha EM  Lee WJ 《Science (New York, N.Y.)》2008,319(5864):777-782

Although commensalism with gut microbiota exists in all metazoans, the host factors that maintain this homeostatic relationship remain largely unknown. We show that the intestinal homeobox gene Caudal regulates the commensal-gut mutualism by repressing nuclear factor kappa B-dependent antimicrobial peptide genes. Inhibition of Caudal expression in flies via RNA interference led to overexpression of antimicrobial peptides, which in turn altered the commensal population within the intestine. In particular, the dominance of one gut microbe, Gluconobacter sp. strain EW707, eventually led to gut cell apoptosis and host mortality. However, restoration of a healthy microbiota community and normal host survival in the Caudal-RNAi flies was achieved by reintroduction of the Caudal gene. These results reveal that a specific genetic deficiency within a host can profoundly influence the gut commensal microbial community and host physiology.  相似文献   

Nonresonant multiple spin echoes     

Brill TM  Ryu S  Gaylor R  Jundt J  Griffin DD  Song YQ  Sen PN  Hürlimann MD 《Science (New York, N.Y.)》2002,297(5580):369-372

Nonresonant manipulation of nuclear spins can probe large volumes of sample situated in inhomogeneous fields outside a magnet, a geometry suitable for mobile sensors for the inspection of roads, buildings, and geological formations. However, the interference by Earth's magnetic field causes rapid decay of the signal within a few milliseconds for protons and is detrimental to this method. Here we describe a technique to suppress the effects of Earth's field by using adiabatic rotations and sudden switching of the applied fields. We observed hundreds of spin echo signals lasting for more than 600 milliseconds and accurately measured the relaxation times of a liquid sample.  相似文献   

Polyhydroxylated alkaloids isolated from mulberry trees (Morusalba L.) and silkworms (Bombyx mori L.)   总被引：2，自引：0，他引：2  

Asano N  Yamashita T  Yasuda K  Ikeda K  Kizu H  Kameda Y  Kato A  Nash RJ  Lee HS  Ryu KS 《Journal of agricultural and food chemistry》2001,49(9):4208-4213

New polyhydroxylated alkaloids, (2R,3R,4R)-2-hydroxymethyl-3,4-dihydroxypyrrolidine-N-propionamide from the root bark of Morus alba L., and 4-O-alpha-D-galactopyranosyl-calystegine B(2) and 3 beta,6 beta-dihydroxynortropane from the fruits, were isolated by column chromatography using a variety of ion-exchange resins. Fifteen other polyhydroxylated alkaloids were also isolated. 1-Deoxynojirimycin, a potent alpha-glucosidase inhibitor, was concentrated 2.7-fold by silkworms feeding on mulberry leaves. Some alkaloids contained in mulberry leaves were potent inhibitors of mammalian digestive glycosidases but not inhibitors of silkworm midgut glycosidases, suggesting that the silkworm has enzymes specially adapted to enable it to feed on mulberry leaves. The possibility of preventing the onset of diabetes and obesity using natural dietary supplements containing 1-deoxynojirimycin and other alpha-glucosidase inhibitors in high concentration is of great potential interest.  相似文献   

Diversity in landraces and cultivars of bottle gourd (Lagenaria siceraria; Cucurbitaceae) as assessed by random amplified polymorphic DNA   总被引：1，自引：0，他引：1  

Deena Decker-Walters  Jack Staub  Ana López-Sesé  Eijiro Nakata 《Genetic Resources and Crop Evolution》2001,48(4):369-380

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Identification of six phenylpropanoids from garlic skin as major antioxidants   总被引：3，自引：0，他引：3  

Ichikawa M  Ryu K  Yoshida J  Ide N  Kodera Y  Sasaoka T  Rosen RT 《Journal of agricultural and food chemistry》2003,51(25):7313-7317

The extract of garlic skins (peels) showed strong antioxidant activity, and some responsible constituents were isolated and identified. Garlic (Allium sativum L.) has been used as an herbal medicine, but there is no report on the health benefits of the skin or peel. In this study, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of garlic skin extract was evaluated. Using chromatographic techniques, the active constituents were isolated and subsequently identified. Analyses by high-performance liquid chromatography coupled with a photodiode array detector (HPLC-PDA) suggested that these compounds were phenylpropanoids, which had a characteristic absorbance at 300-320 nm. Liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance analyses allowed the chemical structures of the isolated constituents to be postulated. The proposed compounds were subsequently synthesized and compared with the constituents in the extract using HPLC-PDA and LC-MS. N-trans-Coumaroyloctopamine, N-trans-feruloyloctopamine, guaiacylglycerol-beta-ferulic acid ether, and guaiacylglycerol-beta-caffeic acid ether were identified as were trans-coumaric acid and trans-ferulic acid. Also, the antioxidant activities of these compounds were determined.  相似文献   

Artificial incubation of Japanese crayfish (Cambaroides japonicus) eggs by using a simple, easy method with a microplate     

Kazuyoshi Nakata  Hajime Matsubara  Seiji Goshima 《Aquaculture (Amsterdam, Netherlands)》2004,230(1-4):273-279

We developed a simple, easy method with a microplate to artificially incubate Japanese crayfish (Cambaroides japonicus) eggs for their cultivation. We prepared 6-, 12-, 24-, 48-, and 96-well microplates containing sterile water heated to 5, 10, 15, and 20 °C. Fourteen experimental groups for each water temperature were prepared for each of different water volumes (0.125–10 ml) in each well. One embryonic egg was placed in each well. Experiments were also conducted with water collected from the lake where the eggs were harvested from and held at 15 °C. In the microplates with sterile water, high proportions of eggs hatched (60–100%) at 15 °C in all volumes of water, although the proportions of hatching were low (0–20%) at 5, 10, and 20 °C. All eggs died in the experiments that used lake water. We conclude that the 96-well would be the most effective size to hatch crayfish eggs in, because of its convenience. This method using a microplate is simpler and easier compared with methods of previous studies to artificially incubate crayfish eggs, and therefore it might be useful to incubate eggs of other freshwater crayfish species.  相似文献   

Interannual variation in spring biomass and gut content composition of copepods in the Kuroshio current, 1971–89     

K. Nakata  S. Koyama  & Y. Matsukawa 《Fisheries Oceanography》2001,10(4):329-341

We examined the effects of climate factors on interannual variations of copepod biomass and gut content composition in early spring in the Kuroshio and the slope water off the Pacific coast of central Japan from 1971 to 1989. The biomass trends were different for large (prosomal length ≥ 1 mm) and small (prosomal length < 1 mm) copepods in both waters. Peaks in biomass of large copepods decreased in magnitude, and the biomass of small copepods was low around 1980. For the large copepods in the Kuroshio, 3-year running mean biomass was related to the Kuroshio meander index. The yearly mean biomass was related to diatom abundance in the gut which, in turn, was related to wind speed and temperature. The 3-year running mean biomass of large copepods in the slope water was positively related to solar radiation in March. The biomass of small copepods in both waters was negatively related to solar radiation in February, and years with high biomass of small copepods corresponded with not only the years with high abundance of larger foods (diatoms and micro-sized foods) in copepod guts, but also with the years with high abundance of the nano-sized foods. We hypothesize that nutrient supply to upper layers regulates interannual variation of biomass of large copepods in the Kuroshio. Thus, climate influences both size composition and biomass of copepods in and near the Kuroshio in early spring.  相似文献