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  • 1
    Electronic Resource
    Electronic Resource
    Evidence for the migration of ZnOx in a Cu/ZnO methanol synthesis catalyst (1994)
    Springer
    Catalysis letters 27 (1994), S. 67-78 
    Details
    ISSN: 1572-879X
    Keywords: methanol synthesis ; Cu/ZnO catalyst ; Cu-Zn alloy ; effect of reduction temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The behavior and role of ZnO in Cu/ZnO catalysts for the hydrogenations of CO and CO2 were studied using XRD, TEM coupled with EDX, TPD and FT-IR. As the reduction temperature increased, the specific activity for the hydrogenation of CO2 increased, whereas the activity for the hydrogenation of CO decreased. The EDX and XRD results definitely showed that ZnO x (x = 0–1) moieties migrate onto the Cu surface and dissolve into the Cu particle forming a Cu-Zn alloy when the Cu/ZnO catalysts were reduced at high temperatures above 600 K. The content of Zn dissolved in the Cu particles increased with reduction temperature and reached ∼ 18% at a reduction temperature of 723 K. The CO-TPD and FT-IR results suggested the presence of Cu+ sites formed in the vicinity of ZnO x on the Cu surface, where the Cu+ species were regarded as an active catalytic component for methanol synthesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00806979
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  • 2
    Electronic Resource
    Electronic Resource
    Methanol synthesis over a Zn-deposited copper model catalyst (1995)
    Springer
    Catalysis letters 31 (1995), S. 325-331 
    Details
    ISSN: 1572-879X
    Keywords: methanol synthesis ; copper catalyst ; role of ZnO ; XPS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Methanol synthesis by the hydrogenation of CO2 over Zn-deposited polycrystalline Cu was studied using surface science techniques. The Zn sub-monolayer was oxidized by the reaction mixture during the reaction at 523 K, leading to the formation of ZnO species. The kinetic results definitely showed that the ZnO species on the Cu surface promoted the catalytic activity of methanol formation, where the activity of Cu increased by a factor of 6 at the Zn coverage of 0.17. A volcano-shaped curve was obtained for the correlation between the Zn coverage and the catalytic activity, which was very similar to the correlation curve between the oxygen coverage and the specific activity for methanol formation previously obtained for the Cu powder catalysts. The role of ZnO in Cu/ZnO based catalysts was ascribed to the stabilization of Cu+ species by the ZnO moieties on the Cu surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00808596
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  • 3
    Electronic Resource
    Electronic Resource
    The synergy between Cu and ZnO in methanol synthesis catalysts (1996)
    Springer
    Catalysis letters 38 (1996), S. 157-163 
    Details
    ISSN: 1572-879X
    Keywords: methanol synthesis ; Cu/ZnO catalyst ; effect of reduction temperature ; oxygen coverage ; physical mixture ; Cu-Zn alloy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The hydrogenation of CO2 over physically-mixed Cu/SiO2 and ZnO/SiO2 was carried out to clarify the synergetic effect between Cu and ZnO in Cu/ZnO methanol synthesis catalysts. The activity of the physical mixtures significantly increased with increasing reduction temperature in the range of 573–723 K. TEM-EDX results definitely showed that ZnOx moieties migrated from ZnO/SiO2 particles onto the surface of Cu particles when the physical mixtures were reduced at high temperatures above 573 K. Upon the migration of the ZnOx species, the oxygen coverage on the surface of Cu, measured after the hydrogenation of CO2, increased with the reduction temperature. The results clearly showed that the synergetic effect of ZnO in the physical mixtures can be ascribed to the creation of active sites such as Cu+ which the ZnOx moieties stabilize on the Cu surface. Further, XRD results showed that the migrated ZnOx species partly dissolved into the Cu particles to form a Cu—Zn alloy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00806562
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  • 4
    Electronic Resource
    Electronic Resource
    The role of metal oxides in promoting a copper catalyst for methanol synthesis (1994)
    Springer
    Catalysis letters 25 (1994), S. 271-276 
    Details
    ISSN: 1572-879X
    Keywords: methanol synthesis ; copper catalyst ; oxygen coverage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The coverage of oxygen formed on the surface of catalysts during methanol synthesis from CO2 has been measured for copper-based catalysts including various metal oxides using a method called reactive frontal chromatography (RFC). An excellent correlation between the specific activity for methanol synthesis and the oxygen coverage (θ) was obtained, where the activity increased linearly with oxygen coverage atθ〈0.16 and then decreased atθ〉0.18. The results strongly indicate that the support effect or addition of metal oxides revealed in methanol synthesis over copper catalysts is ascribed to the ratio of Cu+ to Cu0 on the surface of copper particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00816307
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  • 5
    Electronic Resource
    Electronic Resource
    Changes in cell surface and intracellular glycoproteins of trophoblastic giant cells during mouse placentation (1991)
    Springer
    Histochemistry and cell biology 95 (1991), S. 541-548 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Changes in lectin bindings of mouse trophoblastic giant cells (TGCs) were examined by light and electron microscopy. Neither Griffonia simplicifolia agglutinin (GS)-II nor succinyl-wheat germ agglutinin (s-WGA) bound to the 1st and 2nd TGCs on day 6.5 post coitum (p.c.), but did so from days 8.5 to 12.5 p.c. Positive reactions with s-WGA were localized in the perinuclear region and cell surface of both 1st and 2nd TGCs; while GS-II bound only to the perinuclear region, where it appeared as network-like deposits. This region was identified as well-developed Golgi lamellae by electron microscopy. Moreover, SDS-PAGE and lectin-blot analysis of the 1st TGCs indicated that the intensity of s-WGA and GS-II bindings increased in the glycoproteins of approximately 43, 40, 37, and 26 kDa and in those of 43 and 38 kDa, respectively, during the 8.5th to 10.5th day p.c. The reaction with GS-I was detected on cell surface of both the 1st and 2nd TGCs on day 6.5 p.c. The reaction in the 1st TGCs was intensely positive throughout their development, whereas the reactivity decreased in the 2nd TGCs on day 10.5 p.c. and completely disappeared on day 12.5 p.c. The GS-I reaction in TGCs was more intense at the maternal side than at the embryonic side. These results suggest that certain Gal and/or GlcNAc glycoproteins on the cell surface and in Golgi lamellae of TGCs dynamically change from the 8.5th to 10.5th day p.c. in association with mouse placentation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00266739
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  • 6
    Electronic Resource
    Electronic Resource
    Changes in lectin binding pattern of gonalds of developing mice (1989)
    Springer
    Histochemistry and cell biology 92 (1989), S. 37-42 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Changes in lectin binding of developing fetal mouse testes and ovaries were examined by light and electron microscopy, with much attention paid particularly to those in carbohydrates of germ cells. Characteristic binding patterns were observed with three lectins (BPA, GS-I, and GS-II) in the germ cells and the somatic cells during the process of testicular and ovarian development. GS-I and BPA, which showed similar binding patterns, preferentially bound to the plasma membrane and small dense bodies (SDB) of germ cells in both testes and ovaries during the 12th to 14th day post coitum (p.c.). In the fetal testes on day 16 p.c., the reaction with both GS-I and BPA completely disappeared. While, in the ovaries, a weak reaction with these lectins was retained as it was in germ cells until the 16th day p.c. The reaction with GS-II was restricted to Sertoli cells in the fetal testes during the 12th to 14th day p.c., and thereafter disappeared on day 16 p.c. The distribution of GS-II binding sites was in agreement with that of the glycogen granules. No positive staining with GS-II was seen in the ovaries throughout their development. These results indicate that certain glycoconjugates containing d-galactose and N-acetyl-d-galactosamine residues are expressed on the cell surface and in the SDB of germ cells during the period of the 12th to 14th day p.c., and that striking changes in function as well as in structure may take place in both germ cells and somatic cells during the 14th to 16th day p.c. in association with testicular and ovarjan development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00495013
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  • 7
    Electronic Resource
    Electronic Resource
    Localization of forssman glycolipid and GM1 ganglioside intracellularly and on the surface of germ cells during fetal testicular and ovarian development of mice (1990)
    Springer
    Histochemistry and cell biology 94 (1990), S. 561-568 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Changes in the expression pattern and intracellular localization of Forssman glycolipid (FA) and GM1 ganglioside (GM1) in fetal mouse gonads were examined during germ cell differentiation by immunofluorescence microscopy and immunoelectron microscopy. In male germ cells from the 12th to 14th day p.c., anti-FA binding was localized in granular structures aggregated on one side of the cytoplasm and/or in the plasma membrane. On day 16 p.c., some germ cells still showed patch-like positive reactions in the plasma membrane, but by day 18 p.c., positive reactions for FA had completely disappeared. The female germ cells showed granular bindings of anti-FA scattered throughout their cytoplasm during the 13th to 16th day p.c., although the positive reactions in female germ cells on day 12 p.c. tended to be found in one side of cytoplasm and/or plasma membrane similar to those in male germ cells from 12th to 14th day p.c. On day 18 p.c., positive reactions remained in the plasma membrane of some germ cells, but these positive reactions disappeared before birth. Immunoelectron microscopic observation showed that the sites of anti-FA bindings were equivalent to the “small dense bodies” (SDB) and the Golgi lamellae both in male and female germ cells. On the other hand, GM1 was not detected in male germ cells at any time during fetal testicular development, whereas an anti-GM1 reaction was detected in the plasma membrane of female germ cells from the 16th to 18th day p.c. (oocytes in the first meiotic prophase). Therefore, these results indicate that kinetic translocation of FA between the plasma membrane and the SDB and Golgi lamellae takes place during germ cell differentiation in fetal gonads. Moreover, the ganglioside composition containing GM1 seems to change in association with the first meiotic prophase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00271982
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  • 8
    Electronic Resource
    Electronic Resource
    Mouse Asc-1 (asc-type amino acid transporter 1) maps to chromosome 7, region B1-B5 (2000)
    Springer
    Chromosome research 8 (2000), S. 456-456 
    Details
    ISSN: 1573-6849
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009299311416
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  • 9
    Electronic Resource
    Electronic Resource
    Measurement of impact parameter dependent probabilities and total cross sections for targetK-shell ionization by He+ ions (1987)
    Springer
    The European physical journal 4 (1987), S. 339-342 
    Details
    ISSN: 1434-6079
    Keywords: 34.50.Hc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have measured the impact parameter dependent K-shell ionization probabilitiesP K (b) of Ca, Cr and Cu from collisions with 4.04 MeV He+ ions by particle-K X ray coincidences. A dependence on the target thickness was investigated to study a possible influence of multiple collisions onP K (b). We measured the total cross section σ K forK vacancy production simultaneously withP K (b) and σ K agrees within 30% with the integratedP K (b). A comparison of theP K (b) and σ K with SCA calculations of Trautmann et al. using RHFS wavefunctions for united atom and separated atom states is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01384886
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  • 10
    Electronic Resource
    Electronic Resource
    Electron spectroscopy of doubly-excited helium-like ions (1991)
    Springer
    The European physical journal 21 (1991), S. S225 
    Details
    ISSN: 1434-6079
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Ejected electrons from helium-like doubly-excited carbon and boron ions, produced by C6+ and B5+ with He collisions, were measured by the zero-degree electron spectroscopy technique. Electrons from configurations 21nl were observed in a wide energy range.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426299
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