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  • 1
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 336-338 (Apr. 2007), p. 1182-1184 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The densified α-sialon ceramics with the compositions RE0.333Si10Al2ON15 (RE= Yb,Y, Dy,Sm and Nd) were prepared by a two-step hot-pressing sintering. The ceramics doped with smaller cations(Yb3+, Y3+ and Dy3+) are fully composed of α-sialon, while the larger cation-doped ceramics (Sm3+ andNd3+) exist a few M′ (RE2Si3-xAlxO3+xN4-x) phases. A small amount of β-sialon phases are also found inthe Nd-doped sialon. Microstructure observation indicates that Yb-α-sialon consists of equiaxial grains,but when increasing the radius of the doped cations, the elongated α-sialon grains form and the aspectratio of grain increases slightly. TEM observation indicated that almost no intergranular phases exist inthe α-sialon doped with smaller cations, but a few exist in Sm- and Nd-doped α-sialon. Some elongatedα-sialon grains with grain core were found. EDX results suggest that the compositions of the grain shelland that of the core are different. Surrounding the grain core, some misfit dislocations were seen
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 47-50 (June 2008), p. 1055-1058 
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: ZnO microrods were synthesized on Si (111) sustrate by thermal evaporation at thetemperature of 700 °C. Different growth environments bring to the different morphologies of thedepositions. By analyzing the scanning electrical microscopy (SEM) images, a growth mechanismof the microrods is schematically put forward. Transmission electronic microscopy (TEM) imagesshow that the perfectly epitaxial relationship between the ZnO nanorods and microrods
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  • 3
    Electronic Resource
    Electronic Resource
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 86 (2003), S. 0 
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The yttrium–sialon ceramics with the composition of Y0.333Si10Al2ON15 and an excess addition of Y2O3 (2 or 5 wt%) were fabricated by hot isostatic press (HIP) sintering at 1800°C for 1 h. The resulting materials were subsequently heat-treated in the temperature range 1300–1900°C to investigate its effect on the α→β-sialon phase transformation, the morphology of α-sialon grains, and mechanical properties. The results show that α-sialons stabilized by yttrium have high thermal stability. An adjustment of the α-sialon phase composition is the dominating reaction in the investigated Y–α-sialon ceramics during low-temperature annealing. Incorporation of excess Y2O3 could effectively promote the formation of elongated α-sialon grains during post-heat-treating at relatively higher temperature (1700° and 1900°C) and hence resulted in a high fracture toughness (KIC= 6.3 MPa·m1/2) via grain debonding and pullout effects. Although the addition of 5 wt% Y2O3 could promote the growth of elongated α grains with a higher aspect ratio, the higher liquid-phase content increased the interfacial bonding strength and therefore hindered interface debonding and crack deflection. The heat treatment at 1500°C significantly changed the morphology of α-sialon grains from elongated to equiaxed and hence decreased its toughness.
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  • 4
    Electronic Resource
    Electronic Resource
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 84 (2001), S. 0 
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Barium aluminosilicate (BAS) glass-ceramic composites reinforced with various volume percents (0, 10, 20, 30, 40 vol%) of SiC whiskers were fabricated by hot pressing. The microstructure, the whisker/matrix interface structure, the phase constitution, and the mechanical properties of the composites were systematically studied by means of SEM, TEM, and XRD techniques as well as by indentation crack microfracture and single-edge-notched-beam bend testing. It was demonstrated that the incorporation of SiC whiskers could significantly increase the flexural strength and fracture toughness of BAS glass-ceramic matrices. The addition of active Al2O3 to the BAS matrix reduced the amount of SiO2 in the matrix, forming needlelike mullite, which further improved the mechanical properties.
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Munksgaard International Publishers
    Physiologia plantarum 124 (2005), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Effect of low temperature on anthocyanin accumulation in seedlings of Alternanthera bettzickiana and activity changes of calmodulin (CaM) and Ca2+-ATPase under low temperature were studied. Results indicate that the increase of anthocyanin content was obviously paralleled not only by the activity of CaM but also by the activity of Ca2+-ATPase. In addition, seedlings were pretreated with CaM antagonist [chlorpromazine (CPZ)] before low-temperature treatment in order to further investigate whether CaM plays a role in anthocyanin accumulation. CPZ pretreatment inhibited the activity of CaM and Ca2+-ATPase and caused a reduction in anthocyanin levels. Hence, it is concluded that CaM and Ca2+-ATPase were directly correlated with anthocyanin accumulation under low temperature, Ca2 ± CaM may be involved in low-temperature signal transduction leading anthocyanin synthesis.
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  • 6
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 302-303 (Jan. 2006), p. 184-190 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 7
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 302-303 (Jan. 2006), p. 438-443 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 8
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 353-358 (Sept. 2007), p. 1525-1528 
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Ytterbia and Lutecia were adopted to stabilize α-sialon ceramics during a two-step hotpress sintering, respectively. Although Yb3+ and Lu3+ possess the similar small ion size (0.86 Å and0.85 Å) as two adjacent rare-earth elements, Yb- and Lu-α-sialon ceramics present very differentmicrostructure and properties. Yb-α-sialon ceramic is fully composed of α-sialon phase without anysecondary phase. The ceramic incorporated with Lu2O3 also consists of α-sialon phase, but a traceamount of intergranular phase J′ (Lu4Si2-xAlxO7+xN2-x) still remains at the boundary. Microstructureobservation indicates the fully equiaxial grain morphology of Yb-α-sialon ceramic. However,elongated grains appear in the Lu-α-sialon ceramic, coexisting with small equiaxed grains. Owingto the almost full α-sialon phase assemblage, both ceramics present high hardness with the value ofover 21 GPa. Lu-α-sialon ceramic possesses good toughness, which is attributed to the elongatedgrains assisting the facilitation of toughening mechanism. The equiaxied grain morphology resultsin a comparatively lower toughness for Yb-α-sialon ceramic
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  • 9
    ISSN: 1573-4919
    Keywords: integrin ; human hepatocelluar carcinoma ; tumorigenicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Integrin α 5 β 1 and α 2 β 1 are the major integrin receptors in human hepatocytes. However, in human hepatocellular carcinoma cells it was found that the expression of integrin α 5 β 1 was decreased and another integrin α 6 β 1 increased. In this study, the SMMC7721 human hepatocellular carcinoma cells cotransfected or singlely transfected with integrin α 5 and/orβ 1 cDNAs were established, and designatedα 5 β 1.6-7721, α 5.3-7721, and β 1.6-7721 cell lines, respectively. Transfection with cDNAs of integrin α 5 and β 1 subunits resulted in the overexpression of each integrin and modified biological properties, including a slowed growth rate, changes in the cell cycle from 15.5% of control cells in the G2/M phase to 12.1%, 9.6% and 9.4% in α 5.3-7721, β 1.6-7721, α 5 β 1.6-7721, respectively, and a decrease in the Cell Mitosis Index from 1.6 in controls to 0.96, 0.95, and 0.72, and 34%, 28% and 52% derived from colony forming ability, respectively. Tumorigenicity was also tested in nude mice with inoculation of cells subcutaneously. Tumor masses growing in nude mice following inoculation with β 1.6-7721,and α 5 β 1.6-7721 cells weighed only 52% or 31% those of control cells. These results indicated that deletion or low expression of integrin α 5 β 1 may play an important role in the development of hepatocellular carcinoma. Therefore, induction of expression of the integrin α 5 β 1 in malignant cells could be a potential means of treating hepatocellular carcinoma.
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  • 10
    ISSN: 1617-4623
    Keywords: Phosphoglycerate kinase ; Drosophila ; Nucleotide sequence ; Glycolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The gene that encodes phosphoglycerate kinase in Drosophila melanogaster (Pgk) has been isolated and characterized. There is a single copy of Pgk in the Drosophila genome located at cytogenetic position 23A1-2. Transcripts of Pgk are 1.6 kb long and are found during development with a profile similar to the expression pattern of other genes of the glycolytic pathway. There are substantial amounts of maternal transcript in early embryos which decline in abundance until mid-embryogenesis when transcript levels increase; levels remain high, during larval stages, fall during pupariation and rise again at emergence. The nucleotide sequence of the Pgk gene reveals two small introns, one of which is at a position identical to the site of an intron found in Pgk genes from other organisms. The Pgk gene has no TATA box in the region of transcription initiation and has multiple transcription initiation sites that are closely spaced within 110 nucleotides of the translation start site.
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