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排序方式: 共有1198条查询结果,搜索用时 15 毫秒
61.
T Masubuchi S Koyama E Sato A Takamizawa K Kubo M Sekiguchi S Nagai T Izumi 《Canadian Metallurgical Quarterly》1998,153(6):1903-1912
Inflammatory cells accumulate within the lungs of cigarette smokers. Current concepts suggest that these cells can induce protease-antiprotease and/or oxidant-antioxidant imbalance(s), which may damage the normal lung alveolar and interstitial structures. Because type II pneumocytes line the alveolar space, and because the inflammatory cells migrate and reside at the alveolus, we postulated that the type II pneumocytes might release chemotactic activity for neutrophils and monocytes in response to smoke extract. To test this hypothesis, A549 cells were cultured and the supernatant fluids were evaluated for the neutrophil and monocyte chemotactic activity (NCA and MCA) by a blind-well chamber technique. A549 cells released NCA and MCA in response to smoke extract in a dose- and time-dependent manner (P < 0.05). Checkerboard analysis showed that the activity was chemotactic. Partial characterization of NCA and MCA revealed that the activity was partly heat labile, trypsin sensitive, and ethyl acetate extractable. Lipoxygenase inhibitors and cycloheximide inhibited the release of NCA and MCA. Molecular sieve column chromatography showed multiple peaks for both NCA and MCA. NCA was inhibited by anti-human-interleukin (IL)-8 antibody, granulocyte colony-stimulating factor (G-CSF) antibody, or leukotriene (LT)B4 receptor antagonist. Monocyte chemoattractant protein (MCP)-1 antibody or LTB4 receptor antagonist inhibited MCA. Immunoreactive IL-8, G-CSF, MCP-1, and LTB4 significantly increased in the supernatant fluids in response to smoke extract. These data suggest that the type II pneumocytes may release NCA and MCA and modulate the inflammatory cell recruitment into the lung. 相似文献
62.
Implications of cultural accommodation–hybridization were explored within the framework of individualism–collectivism. Individualism highlights the personal and centralizes individuals as the unit of analyses, whereas collectivism highlights the social and contextualizes individuals as parts of connected social units. In 2 experiments, the ways in which individualism, collectivism, and identity salience influence social obligation to diverse others was explored. The authors varied the personal goal interrupted (achievement–pleasure), the target (individual–group), and focus (in-group–larger society) of social obligation within subjects. The authors hypothesized that collectivism would increase obligation to the in-group when identity was made salient; that individualism alone would dampen social obligation; and that cultural accommodation–hybridization (being high in both individualism and collectivism) would increase obligation to larger society. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
63.
K Izumi K Kitaura Y Chone H Tate T Nakagawa Y Suzuki K Matsumoto 《Canadian Metallurgical Quarterly》1994,85(6):563-566
Neoplastic lesions of the kidneys in untreated Long-Evans Cinnamon (LEC) rats of 57-118 weeks old (85 males and 34 females) and male F344 rats of 64-93 weeks old (59 males) were examined histologically. The incidences of renal cell tumors in male and female LEC rats were 6/80 (8%) in weeks 57-65, 3/19 (16%) in weeks 66-75, 3/8 (38%) in weeks 76-105 and 7/12 (58%) in weeks 106-118. Of these tumors, 13 were microscopic adenomas and 7 were renal cell carcinomas. The copper content of the kidneys was about three times higher in LEC rats than in F344 rats (P < 0.001), but the iron content of the kidneys was similar in the two strains. 相似文献
64.
The relationship between ductility and material parameters such as grain-boundary (GB) precipitate size and dimple size in an Al-6.0% Zn-2.6% Mg alloy has been studied. Under the condition of a given GB precipitate size, the ductility increases with decreasing number of GB precipitates and dimples per unit area. The critical GB precipitate sizes acting as the nuclei for void formation are deduced. 相似文献
65.
Acidophilic xylanase from Aureobasidium pullulans: efficient expression and secretion in Pichia pastoris and mutational analysis 总被引:1,自引:0,他引:1
Tanaka H Okuno T Moriyama S Muguruma M Ohta K 《Journal of Bioscience and Bioengineering》2004,98(5):338-343
A yeast-like fungus Aureobasidium pullulans var. melanigenum strain ATCC 20524 produces an extracellular acidophilic endo-1,4-beta-xylanase with an optimum pH of 2.0 [Ohta et al., J. Biosci. Bioeng., 92, 262-270 (2001)]. The xynI cDNA encoding the precursor protein (XynI) was expressed in the methylotrophic yeast Pichia pastoris under the control of the alcohol oxidase I gene promoter. The 34 amino acid prepro-signal peptide of the A. pullulans XynI directed the efficient secretion of 178 mg of active xylanase per liter of the culture medium. The secretion level of the xylanase with its own signal peptide was comparable to that of the mature protein fused to the prepro leader from Saccharomyces cerevisiae alpha-mating factor and twofold higher than that of the mature protein fused to the pre-type signal peptide from P. pastoris acid phosphatase. The N-terminal amino acid sequence and the apparent M(r) of 24 kDa of the secreted recombinant protein indicated the native-like processing of the A. pullulans XynI signal sequence in P. pastoris. The three-dimensional model and mutational analysis of the xynI gene product showed that Asp-73 and Glu-157 residues located at the upper and lower edges of the active site cleft, respectively, play a significant role in its low pH optimum. 相似文献
66.
Standardization of transmission system for television satellite broadcasting with multiple sound and/or data signals for an operational broadcasting satellite system is under study in Japan. Based upon result obtained from the BSE experiment, several transmission systems have been developed at the NHK (Japan Broadcasting Corporation). 相似文献
67.
In situ dynamic observations of the deformation and fracture characteristics of alpha/beta brass two-phase bicrystals were made by the solid diffusion method. The results indicated clearly that the crack initiation site was at the interface. The crack propagation direction, in both the alpha and beta phases, was found to be orientation dependent. Complementary experiments on alpha and beta brass single crystals confirmed the theories and results obtained previously on ductile single crystals.On leave from the Mechanical Engineering Department, Al-Azhar University, Cairo, Egypt. 相似文献
68.
Suzuki I Yamada K Yamakawa T Hashiba M Akazawa K 《Computer methods and programs in biomedicine》2003,70(3):253-258
We developed a low cost, user-friendly multimedia delivery system, to provide medical lectures saved as multimedia contents to persons engaged in medicine. This system was created using the RealSystem package with the TCP/IP network. Users can review lectures and medical meeting presentations with video and audio through the Internet, whenever convenient. Each medical source of video and slide has been clearly displayed on a screen. Members of medical associations or medical students can easily review the most interesting parts of these files. This system is being used efficiently in distance learning and aids the diffusion of the latest information and technology to busy physicians and medical students. 相似文献
69.
A unified scheme for treating generalized superselection sectors is proposed on the basis of the notion of selection criteria to characterize states of relevance to each specific domain in quantum physics, ranging from the relativistic quantum fields in the vacuum situations with unbroken and spontaneously broken internal symmetries, through equilibrium and non-equilibrium states to some basic aspects in measurement processes. This is achieved by the help of c q and q c channels: the former determines the states to be selected and to be parameterized by the order parameters, and the latter provides the physical interpretations of selected states in terms of order parameters. This formulation extends the traditional range of applicability of the Doplicher-Roberts construction method for recovering the field algebra and the gauge group (of the first kind) from the data of group invariant observables to the situations with spontaneous symmetry breakdown: in use of the machinery proposed, the physical and mathematical meaning of basic structural ingredients associated with the spontaneously broken symmetry are re-examined, such as the degenerate vacua parameterized by the variables belonging to the relevant homogeneous space, the Goldstone modes and condensates, etc. The geometrical meaning of the space of order parameters is naturally understood in relation with the adjunction as the classifying space of a sector structure. As further examples of applications, some basic notions arising in the mathematical framework of quantum theory are reformulated and examined in connection with control theory. 相似文献
70.
Lysoglycosphingolipids consist of a sphingoid long-chain base and monosaccharide or complex sugar, and they lack the fatty
acyl group present in native glycosphingolipids. Less than 1 pmol of lyso-Forssman glycolipid and lysoganglioside GM1 were
detected on a thin-layer chromatogram by an enzyme-linked immunochemical coloration method with anti-Forssman glycolipid antibody
(FOM-1) and cholera toxin B subunit, respectively. Each spot between 1 and 100 pmol lyso-Forssman glycolipid was immunostained
as densely as that of the same amount of native Forssman glycolipid. The density of the lyso-Forssman glycolipid spots increased
proportionally with increment in the amount of lysoglycolipid. The density of spots of 0.2–100 pmol lysoganglioside GM1 was
also proportional to the amount of each lyso-GM1 spot. These results indicated that less than 1 to 100 pmol of deacylated
glycosphingolipid was quantifiable by the immunochemical coloration method with sugar chain-specific antibodies. Glycosphingolipid
deacylase, which cleaved an amide bond between the sphingoid long-chain base and fatty acyl chain in ceramide of glycosphingolipid,
was assayed by detecting the lyso-Forssman glycolipid produced. Lipophilic compounds, recovered from an aliquot of the reaction
mixture of Forssman glycolipid and crude enzyme at appropriate times, were analyzed by thin-layer chromatography. It was found
that lyso-Forssman glycolipid was produced in the first 1–2 h by the enzyme and production increased with incubation time.
This coloration method is more sensitive and specific than the visualization method with a non-specific reagent such as orcinol-sulfuric
acid reagent. 相似文献