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  • 1
    Electronic Resource
    Electronic Resource
    Experimental investigation of Fe-(SiO2) granular films : 35th annual conference on magnetism and magnetic materials (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 4478-4480 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Fe-(SiO2) granular films were fabricated by sputtering with a mosaic target. The fractional area of iron on the target was varied from 0.29 to 0.42. The volume fraction of iron was found from the saturation magnetization to be within 0.03 of that predicted by the target composition. The sample coercivities ranged from Hc = 130 to 950 Oe at room temperature and 690 to 2390 Oe at 77 K. Characteristics relevant for recording media were investigated for the highest-coercivity sample. The squareness values for hysteresis loops measured in and out of the plane of the film, Mr/Ms = 0.54 and 0.43, respectively, indicate that the granules have a uniaxial anisotropy and the easy axes tend to lie more in the plane of the film. The rotational hysteresis was measured at room temperature; the rotational hysteresis integral was calculated to be Ir = 1.56. Because the magnetization reversal is assisted by thermal fluctuation, the low temperature value of Ir was estimated by scaling the measured value by the ratio of the coercivities measured at 77 K and at room temperature. The value of Ir ≈ 0.6 is closest to the theoretical value for the coherent rotation mechanism. The relative decay of magnetization between 30 and 3600 s had a maximum value of ΔM/Ms = 0.10 for a reversal field near Hc. This value falls within the range of the values reported for conventional particulate media, which suggests that a stable transition can be recorded in this material.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.348956
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  • 2
    Electronic Resource
    Electronic Resource
    Age-dependent changes in second messenger and rolipram receptor systems in the gerbil brain (1994)
    Springer
    Journal of neural transmission 97 (1994), S. 135-147 
    Details
    ISSN: 1435-1463
    Keywords: Aging ; second messenger ; rolipram ; gerbil ; phosphodiesterase ; receptor autoradiography ; neurotransmitter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Age-related alterations in binding sites of major second messengers and a selective adenosine 3′,5′-cyclic monophosphate (cyclic-AMP) phospho-diesterase (PDE) in the gerbil brain were analysed by receptor autoradiography. [3H]Phorbol 12,13-dibutyrate (PDBu), [3H]inositol 1,4,5-trisphosphate (IP3), [3H]forskolin, [3H]cyclic-AMP, and [3H]rolipram were used to label protein kinase C (PKC), IP3 receptor, adenylate cyclase, cyclic-AMP dependent protein kinase (PKA), and Ca2+/calmodulin-mdependent cyclic-AMP PDE, respectively. In middle-aged gerbils (16 months old), [3H]PDBu binding was significantly reduced in the hippocampal CA 1 sector, thalamus, substantia nigra, and cerebellum, compared with young animals (1 month old). [3H]IP3 binding revealed significant elevations in the nucleus accumbens, hippocampal CA 1 sector, dentate gyrus, and a significant reduction in cerebellum of middle-aged gerbils. [3H]Forskolin binding in middle-aged animals was significantly increased in the nucleus accumbens and hilus of dentate gyrus, but was diminished in the substantia nigra and cerebellum. On the other hand, in middle-aged animals, [3H]cyclic-AMP binding revealed a significant elevation only in the hippocampal CA3 sector, whereas [3H] rolipram binding showed a significant reduction in the thalamus and cerebellum. Thus, the age-related alteration in these binding sites showed different patterns among various brain regions in middle-aged gerbils indicating that the binding sites of PKC, IP3, and adenylate cyclase are more markedly affected by aging than those of PKA and cyclicAMP PDE and that the hippocampus and cerebellum are more susceptible to these aging processes than other brain regions. The findings suggest that in-tracellular signal transduction is affected at an early stage of senescence and this may lead to neurological deficits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01277949
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  • 3
    Electronic Resource
    Electronic Resource
    Projection domains of MAP2 and tau determine spacings between microtubules in dendrites and axons (1992)
    [s.l.] : Nature Publishing Group
    Nature 360 (1992), S. 674-677 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Insect ovarian Sf9 cells were infected with viruses containing recombinant sequences encoding the three major M APs in mam-malian neurons; MAP2 (1,828 amino acids)7, MAP2C (467 FIG. 1 Sf9 cells infected with recombinant baculovirus expressing MAP2 (a, b), MAP2C (c, d), or tau (e, f) examined ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/360674a0
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  • 4
    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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  • 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
    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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  • 7
    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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  • 8
    Electronic Resource
    Electronic Resource
    Long-term observations in gerbil brain following transient cerebral ischemia: Autoradiographic and histological study (1993)
    Springer
    Metabolic brain disease 8 (1993), S. 181-195 
    Details
    ISSN: 1573-7365
    Keywords: transient ischemia ; dopamine D1 ; naloxone ; forskolin ; receptor autoradiography ; gerbil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated the long-term changes that occur in the gerbil brain following transient cerebral ischemia using histology and receptor autoradiography. Transient ischemia was induced for 3 and 10 min, and animals were allowed to survive for 8 months. A histological study showed that 3-min ischemia caused neuronal damage and mild atrophy only in the hippocampal CA1 sector, and that 10-min ischemia produced severe neuronal damage and marked shrinkage in the hippocampal CA1 and CA3 sectors. Furthermore, severe neuronal damage was seen in the striatum after 10-min ischemia. Autoradiography study revealed that 3-min ischemia caused a significant reduction in [3H] naloxone binding in the frontal cortex, striatum, dentate gyrus, and thalamus, whereas [3H]SCH 23390 and [3H] forskolin binding was not significantly altered in all regions, In contrast, 10-min ischemia produced marked alteration in these binding sites in the striatum, hippocampus, thalamus, and substantia nigra. The alteration was especially notable in the hippocampal region and substantia nigra. These results indicate that hippocampal damage after transient ischemia, compared with that in other regions, is not static, but particularly progressive. Furthermore, they demonstrate a reduction in adenylate cyclase system in the striatum and substantia nigra after transient ischemia. Moreover, our results suggest that long-term survival after ischemia may induce synaptic modification of neurotransmitter and adenylate cyclase system in the hippocampus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00996929
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  • 9
    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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  • 10
    Electronic Resource
    Electronic Resource
    Azimuthal angular dependence of the K-x-ray emission in swift Ne7+-Ne collisions (1991)
    Springer
    The European physical journal 21 (1991), S. S295 
    Details
    ISSN: 1434-6079
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01426330
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