Woodland habitat structures are affected by both agricultural land management and abiotic conditions     

Karen Ikin  Alessio Mortelliti  John Stein  Damian Michael  Mason Crane  Sachiko Okada  Jeff Wood  David Lindenmayer 《Landscape Ecology》2015,30(8):1387-1403

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Inactivation of staphylococcal enterotoxin-A with an electrolyzed anodic solution.   总被引：5，自引：0，他引：5  

Tetsuya Suzuki  Jun Itakura  Masumi Watanabe  Mari Ohta  Yuri Sato  Yuko Yamaya 《Journal of agricultural and food chemistry》2002,50(1):230-234

Electrolyzed anodic NaCl solutions [EW+], prepared by the electrolysis of 0.1% NaCl, have been shown to instantly inactivate most pathogens that cause food-borne disease. Elimination of food-borne pathogens does not necessarily guarantee food safety because enterotoxins produced by pathogens may remain active. We have tested whether EW+ can inactivate Staphylococcal enterotoxin A (SEA), one of the major enterotoxins responsible for food poisoning. Fixed quantities of SEA were mixed with increasing molar ratios of EW+, and SEA was evaluated by reversed-phase passive latex agglutination (RPLA) test, immunoassay, native polyacrylamide gel electrophoresis (PAGE), and amino acid analysis after 30 min incubations. Exposure of 70 ng, or 2.6 pmol, of SEA in 25 microL of PBS to a 10-fold volume of EW+, or ca. 64.6 x 10(3)-fold molar excess of HOCl in EW+, caused a loss of immuno-reactivity between SEA and a specific anti-SEA antibody. Native PAGE indicated that EW+ caused fragmentation of SEA, and amino acid analysis indicated a loss in amino acid content, in particular Met, Tyr, Ile, Asn, and Asp. Staphylococcal enterotoxin-A excreted into culture broth was also inactivated by exposure to an excess molar ratio of EW+. Thus, EW+ may be a useful management tool to ensure food hygiene by food processing industries.  相似文献   

Biological dinitrogen fixation and soil microbial biomass carbon as influenced by free-air carbon dioxide enrichment (FACE) at three levels of nitrogen fertilization in a paddy field   总被引：3，自引：0，他引：3  

Mozammel M. Hoque  Kazuyuki Inubushi  Shu Miura  Kazuhiko Kobayashi  Han-Yong Kim  Masumi Okada  Shingo Yabashi 《Biology and Fertility of Soils》2001,34(6):453-459

An experiment was conducted in an Andosol paddy field in Shizukuishi (Iwate Prefecture, Japan) to determine the effects of free-air CO₂ enrichment (FACE) on biological N₂-fixation activity and soil microbial biomass C at three levels of N application. Rice (Oryza sativa L. cv. Akitakomachi) plants were grown under ambient CO₂ or FACE (ambient +200 µmol mol^-1 CO₂) conditions throughout the growing season with each treatment having four replicated plots. Three levels of N fertilizer (high, standard and low; 15, 9 and 4 g N m^-2, respectively) were applied to examine the effect of different N availability under both CO₂ conditions. Soil samples were collected at four different times from upper and lower soil layers (0-1-cm and 1-10-cm soil depths, respectively) and analysed for biological N₂-fixation (BNF) activity and microbial biomass C (MBC) by the acetylene reduction and chloroform fumigation-extraction methods, respectively. The amounts of chlorophyll-type compounds (Chls), an index of algal growth, and soil available C were also determined. Compared to the ambient CO₂ treatment, the FACE treatment had significantly higher BNF activity in both the upper and lower soil layers at ripening only in low-N soil and at harvest at all three levels of N fertilization rates. MBC was significantly increased by FACE in both the upper and lower soil layers from the middle to later period of the growing season compared to the ambient CO₂ treatment. The FACE treatment increased the Chls in the upper soil layers at ripening only in low-N soil and at harvest at all three levels of N fertilization rates. The amount of soil available C was not significantly different between FACE and ambient CO₂ treatments in both the upper and lower soil layers throughout the cropping season. From these results it can be concluded that the FACE treatment had a significantly positive influence on BNF activity, MBC and Chls at different levels of N fertilization rates in paddy field during the cropping season.  相似文献   

High-performance solid Acid fuel cells through humidity stabilization     

Boysen DA  Uda T  Chisholm CR  Haile SM 《Science (New York, N.Y.)》2004,303(5654):68-70

Although they hold the promise of clean energy, state-of-the-art fuel cells based on polymer electrolyte membrane fuel cells are inoperable above 100 degrees C, require cumbersome humidification systems, and suffer from fuel permeation. These difficulties all arise from the hydrated nature of the electrolyte. In contrast, "solid acids" exhibit anhydrous proton transport and high-temperature stability. We demonstrate continuous, stable power generation for both H2/O2 and direct methanol fuel cells operated at approximately 250 degrees C using a humidity-stabilized solid acid CsH2PO4 electrolyte.  相似文献   

Repeated and sudden reversals of the dipole field generated by a spherical dynamo action     

Li J  Sato T  Kageyama A 《Science (New York, N.Y.)》2002,295(5561):1887-1890

Using long-duration, three-dimensional magnetohydrodynamic simulation, we found that the magnetic dipole field generated by a dynamo action in a rotating spherical shell repeatedly reverses its polarity at irregular intervals (that is, punctuated reversal). Although the total convection energy and magnetic energy alternate between a high-energy state and a low-energy state, the dipole polarity can reverse only at high-energy states where the north-south symmetry of the convection pattern is broken and the columnar vortex structure becomes vulnerable. Another attractive finding is that the quadrupole mode grows, exceeding the dipole mode before the reversal; this may help to explain how Earth's magnetic field reverses.  相似文献   

LIGHT LOCALIZATION IN CTENOPHORES     

Okada YK 《Science (New York, N.Y.)》1926,63(1627):262

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Carbon dioxide degassing by advective flow from Usu volcano, Japan   总被引：1，自引：0，他引：1  

Hernández PA  Notsu K  Salazar JM  Mori T  Natale G  Okada H  Virgili G  Shimoike Y  Sato M  Pérez NM 《Science (New York, N.Y.)》2001,292(5514):83-86

Magmatic carbon dioxide (CO2) degassing has been documented before the 31 March 2000 eruption of Usu volcano, Hokkaido, Japan. Six months before the eruption, an increase in CO2 flux was detected on the summit caldera, from 120 (September 1998) to 340 metric tons per day (September 1999), followed by a sudden decrease to 39 metric tons per day in June 2000, 3 months after the eruption. The change in CO2 flux and seismic observations suggests that before the eruption, advective processes controlled gas migration toward the surface. The decrease in flux after the eruption at the summit caldera could be due to a rapid release of CO2 during the eruption from ascending dacitic dikes spreading away from the magma chamber beneath the caldera.  相似文献   

Early origin and recent expansion of Plasmodium falciparum     

Joy DA  Feng X  Mu J  Furuya T  Chotivanich K  Krettli AU  Ho M  Wang A  White NJ  Suh E  Beerli P  Su XZ 《Science (New York, N.Y.)》2003,300(5617):318-321

The emergence of virulent Plasmodium falciparum in Africa within the past 6000 years as a result of a cascade of changes in human behavior and mosquito transmission has recently been hypothesized. Here, we provide genetic evidence for a sudden increase in the African malaria parasite population about 10,000 years ago, followed by migration to other regions on the basis of variation in 100 worldwide mitochondrial DNA sequences. However, both the world and some regional populations appear to be older (50,000 to 100,000 years old), suggesting an earlier wave of migration out of Africa, perhaps during the Pleistocene migration of human beings.  相似文献   

MET amplification leads to gefitinib resistance in lung cancer by activating ERBB3 signaling     

Engelman JA  Zejnullahu K  Mitsudomi T  Song Y  Hyland C  Park JO  Lindeman N  Gale CM  Zhao X  Christensen J  Kosaka T  Holmes AJ  Rogers AM  Cappuzzo F  Mok T  Lee C  Johnson BE  Cantley LC  Jänne PA 《Science (New York, N.Y.)》2007,316(5827):1039-1043

The epidermal growth factor receptor (EGFR) kinase inhibitors gefitinib and erlotinib are effective treatments for lung cancers with EGFR activating mutations, but these tumors invariably develop drug resistance. Here, we describe a gefitinib-sensitive lung cancer cell line that developed resistance to gefitinib as a result of focal amplification of the MET proto-oncogene. inhibition of MET signaling in these cells restored their sensitivity to gefitinib. MET amplification was detected in 4 of 18 (22%) lung cancer specimens that had developed resistance to gefitinib or erlotinib. We find that amplification of MET causes gefitinib resistance by driving ERBB3 (HER3)-dependent activation of PI3K, a pathway thought to be specific to EGFR/ERBB family receptors. Thus, we propose that MET amplification may promote drug resistance in other ERBB-driven cancers as well.  相似文献   

Incipient space weathering observed on the surface of Itokawa dust particles     

Noguchi T  Nakamura T  Kimura M  Zolensky ME  Tanaka M  Hashimoto T  Konno M  Nakato A  Ogami T  Fujimura A  Abe M  Yada T  Mukai T  Ueno M  Okada T  Shirai K  Ishibashi Y  Okazaki R 《Science (New York, N.Y.)》2011,333(6046):1121-1125

The reflectance spectra of the most abundant meteorites, ordinary chondrites, are different from those of the abundant S-type (mnemonic for siliceous) asteroids. This discrepancy has been thought to be due to space weathering, which is an alteration of the surfaces of airless bodies exposed to the space environment. Here we report evidence of space weathering on particles returned from the S-type asteroid 25143 Itokawa by the Hayabusa spacecraft. Surface modification was found in 5 out of 10 particles, which varies depending on mineral species. Sulfur-bearing Fe-rich nanoparticles exist in a thin (5 to 15 nanometers) surface layer on olivine, low-Ca pyroxene, and plagioclase, which is suggestive of vapor deposition. Sulfur-free Fe-rich nanoparticles exist deeper inside (<60 nanometers) ferromagnesian silicates. Their texture suggests formation by metamictization and in situ reduction of Fe(2+).  相似文献