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31.
By an immunomagnetic-bead (IMB) separation technique, isolation of Helicobacter pylori from gastrointestinal and fecal samples of gnotobiotic mice infected with the microorganism was tried. The isolation rate of H. pylori from stomach samples after IMB separation was not higher than that of direct culture of the samples. After IMB separation of feces, H. pylori was detectable by PCR, although H. pylori was not culturable. 相似文献
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Shunji Yunoki Toshiyuki Ikoma Akira Monkawa Kazushi Ohta Junzo Tanaka Shinichi Sotome Kenichi Shinomiya 《Journal of the American Ceramic Society》2006,89(9):2977-2979
Gamma irradiation treatment (GIT) is the most widely used sterilization method for biomaterials in spite of the potential to degrade polymers. The adverse effects of GIT on the mechanical properties and biological stabilities of porous hydroxyapatite/collagen (HAp/Col) composites were investigated in this study. Those properties of a porous HAp/Col composite stabilized by dehydrothermal treatment (DHT) drastically decreased by GIT in the same manner as conventional pure Col materials. DHT after GIT could partially eliminate the adverse effects, due to the introduction of cross-linkage among the degraded Col molecules. 相似文献
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Yamamoto K Miyake H Kusunoki M Osaki S 《Journal of Bioscience and Bioengineering》2011,112(6):545-550
The structures of the E277A isomaltase mutant from Saccharomyces cerevisiae in complex with isomaltose or maltose were determined at resolutions of 1.80 and 1.40 Å, respectively. The root mean square deviations between the corresponding main-chain atoms of free isomaltase and the E277Α-isomaltose complex structures and those of free isomaltase and the E277A-maltose complex structures were found to be 0.131 Å and 0.083 Å, respectively. Thus, the amino acid substitution and ligand binding do not affect the overall structure of isomaltase. In the E277A-isomaltose structure, the bound isomaltose was readily identified by electron densities in the active site pocket; however, the reducing end of maltose was not observed in the E277A-maltose structure. The superposition of maltose onto the E277A-maltose structure revealed that the reducing end of maltose cannot bind to the subsite + 1 due to the steric hindrance from Val216 and Gln279. The amino acid sequence comparisons with α-glucosidases showed that a bulky hydrophobic amino acid residue is conserved at the position of Val216 in α-1,6-glucosidic linkage hydrolyzing enzymes. Similarly, a bulky amino acid residue is conserved at the position of Gln279 in α-1,6-glucosidic linkage-only hydrolyzing α-glucosidases. Ala, Gly, or Asn residues were located at the position of α-1,4-glucosidic linkage hydrolyzing α-glucosidases. Two isomaltase mutant enzymes – V216T and Q279A – hydrolyzed maltose. Thus, the amino acid residues at these positions may be largely responsible for determining the substrate specificity of α-glucosidases. 相似文献
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Transparent Nano-Composites Ceramics by Annealing of Amorphous Phase in the HfO2 -Al2 O3 -GdAlO3 System
Shunji Araki Masahiro Yoshimura 《International Journal of Applied Ceramic Technology》2004,1(2):155-160
We have succeeded in fabricating transparent nano-structured ceramics by annealing of the amorphous phase obtained by the solidification of the eutectic melt in the ternary system HfO2 − Al2 O3 − GdAlO3 . The ceramics annealed at 1273 K for 6 hr contained 5-10-nm cubic hafnia grains, and those annealed at 1273 K for 72 hr contained both cubic hafnia and gadolinium aluminum garnet grains 5-10 nm in size. They showed high transparency. Annealing at 1473 K, however, resulted in grain growths that brought about non-transparency. 相似文献
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