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  • 1
    Electronic Resource
    Electronic Resource
    Inhibition of angiogenesis on glycated collagen lattices (1998)
    Springer
    Diabetologia 41 (1998), S. 491-499 
    Details
    ISSN: 1432-0428
    Keywords: Keywords Glycation ; endothelial cell ; angiogenesis ; extracellular matrix ; plasminogen activator ; matrix metalloproteinase.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Advanced glycation endproduct (AGE) accumulation in extracellular matrix proteins has been demonstrated in diabetic patients with a significant correlation with the severity of diabetic complications. AGE accumulation induces matrix protein cross-link formation, resulting in an increased stiffness of matrix fibres and the reduction of the susceptibility of matrix proteins to proteolytic degradation. We examined whether glycation-induced collagen cross-linking may affect vascular endothelial cell behaviours such as invasion, proliferation and differentiation, using the in vitro angiogenesis model of capillary-like structure formation in three-dimensional matrices of collagen type I. Endothelial cells cultured on collagen gel with angiogenic factors (the combination of fibroblast growth factor-2 and vascular endothelial growth factor) invaded the underlying collagen matrix, and organized capillary-like cord structures in the gel. We found that endothelial cell invasion into glycated collagen gel was significantly attenuated without any effect on proteinase activity including cell-associated plasminogen activator and matrix metalloproteinase in the conditioned medium. In addition, subsequent capillary-like cord formation was also inhibited in glycated collagen gel. In contrast, endothelial cell proliferation was enhanced on glycated collagen gel with or without angiogenic factors compared with control collagen gel. These results suggest that the structural alterations of extracellular matrix proteins through the glycation-induced cross-link formation affect the interaction between endothelial cell and extracellular matrix, resulting in the impairment of an adequate neovascularization in diabetic patients. [Diabetologia (1998) 41: 491–499]
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001250050937
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  • 2
    Electronic Resource
    Electronic Resource
    Morphometric and genetic analysis as proof of the existence of two sturgeon species in the Guadalquivir river (1997)
    Springer
    Marine biology 129 (1997), S. 33-39 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Morphometric and genetic methods were used to identify two sturgeon species, Acipenser naccarii Bonaparte, 1836, and A. sturio Linnaeus, 1758, captured in some of the principal rivers of the Iberian Peninsula, including the Guadalquivir. After measuring 25 Iberian specimens from a fishery and several Spanish and Portuguese museums and applying stepwise discriminant analysis (SDA), four specimens preserved in different museums [two specimens from the Guadalquivir river (EBD-8173 and EBD-8174), one specimen from the Tagus river (MUC1) and one specimen from the Mondego river (MUC46B)], as well as five specimens captured in the Guadalquivir river in the 1940s but not preserved (CM1, CM2, CM3, CM4 and CM5), were identified as A. naccarii. After cloning and characterisation of a satellite-DNA family, HindIII, from A.␣naccarii genome, its absence from the genome of A.␣sturio was determined. Using this satellite-DNA as a genetic marker and by means of dot-blotting, we demonstrate that the DNA of the two specimens captured during the mid-1970s in the Guadalquivir river cross-hybridised with HindIII satellite-DNA sequences of A.␣naccarii. We conclude that A. naccarii is autochthonous to the Iberian Peninsula and is not, as was previously believed, endemic to the Adriatic Sea.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050143
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  • 3
    Electronic Resource
    Electronic Resource
    Tunneling measurements of the energy gap in Tl- and Bi-based oxide superconductors (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 5026-5028 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We discuss the behavior found in tunneling measurements obtained by us on two high-Tc superconductors—a ceramic sample of Tl2Ca2Ba2Cu3O10+δ and a Bi4Ca3Sr3Cu4O16+δ single crystal—using a scanning tunneling microscope. We compare some of the experimental curves with simple model calculations, assuming different tunnel-barrier shapes (i.e., different barrier heights, degree of asymmetry, thickness, etc.), and also different quasiparticle density-of-states profiles and tunnel-junction configurations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.344712
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  • 4
    Electronic Resource
    Electronic Resource
    Are the high Tc superconducting materials bulk superconductors or grain boundary percolating network superconductors? (abstract) (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 63 (1988), S. 4213-4213 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied the physical properties of high Tc Y-Ba-Cu-Ox superconducting materials with levitation, ac susceptibility, macroscopic resistivity, resistivity as measured by scanning tunneling microscopy (STM) and Hall effect. Levitation experiments show that the powder of the as-prepared material does not levitate at liquid nitrogen while pellets and powders that have been heated above 450 °C do levitate (are superconducting). These experiments seem to indicate that clustering and intimate contact of fine grains are necessary for levitating. The ac susceptibility experiments show that diamagnetism is extremely sensitive to pellet density. The higher the density and the smaller the field amplitude the less diamagnetic is the system. This is interpreted as evidence for a surface, not a bulk effect. Resistivity at 17 °C measured with macroscopic contacts is of the order of 10 Ω cm. When measured with microscopic STM contacts, a clear semiconducting behavior is observed. This observation does not preclude grain boundary regions with metallic conductivity. We conjecture that the bulk of the grain is semiconducting with a conducting percolative network of grain boundaries that is the source of the superconductivity. We propose a model of a superconductor-metal-superconductor percolative network based on the excitonic model of Allender, Bray, and Bardeen to explain the high values of Tc. Hall measurements show large effective masses in agreement with an excitonic model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.340232
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  • 5
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    Unknown
    Apéndice I: "Notas sobre la Malacofauna del yacimiento paleolítico del Tossal de la Roca (Alicante)" (1982)
    Madrid : Periodicals Archive Online (PAO)
    Trabajos de prehistoria. 39 (1982) 69 
    Details
    ISSN: 0082-5638
    Topics: Archaeology
    Notes: Notas sobre algunos materiales del Tossal de la Roca (Vall d'Alcalá, Alicante)
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:n093-1982-039-00-000003
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  • 6
    Electronic Resource
    Electronic Resource
    HighT c superconductive materials: Bulk or twinned domain/grain boundary percolative network superconductors? (1988)
    Springer
    The European physical journal 70 (1988), S. 9-13 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have studied the physical properties of Y−Ba−Cu−Oxide superconducting materials by using Levitation, AC-susceptibility, macroscopic conductivity, Scanning Tunneling Microscopy (STM) local conductivity, Scanning Electron Microscope (SEM), X-rays, and Hall effect experimental techniques. Our results tend to indicate systematically that the grains formed in the synthesis do not show bulk superconductivity but rather are superconductors at the domain boundaries of the orthorhombic phase. It seems that a coexistence of semiconductor and metallic regions are formed at the twinned domain boundaries. The pellets become superconductors when the grains form clusters and are in intimate contact. This seems to suggest that the bulk of the grains is semiconducting and that a conducting percolative network of grain and domain boundaries may be responsible for the superconductivity. To understand the observed constant high transition temperature we propose a model of semiconductor-metal-semiconductor boundaries that give rise to superconductivity in a model like that of Little, Ginzburg, and Allender-Bray-Bardeen (1).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01320531
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  • 7
    Electronic Resource
    Electronic Resource
    Organization of Repetitive DNA Sequences at Pachytene Chromosomes of Gilthead Seabream Sparus aurata (Pisces, Perciformes) (2000)
    Springer
    Chromosome research 8 (2000), S. 67-72 
    Details
    ISSN: 1573-6849
    Keywords: fish ; fluorescent in-situ hybridization ; meiosis ; repetitive DNA ; synaptonemal complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A method of preparing two-dimensional surface spreads of fish synaptonemal complexes (SCs) associated with fluorescent in-situ hybridization is described. This technique permits a novel approach to the analysis of chromatin organization and the construction of physical maps at meiosis, since surface-spread pachytene chromosomes are several times the length of metaphase chromosomes and the decondensed chromatin loops are attached to the lateral elements of the SC. We have applied this technique to analyze the location and organization of three different repetitive DNA sequences, rDNA, an EcoRI satellite DNA of the Sparidae family and telomere DNA in the gilthead seabream Sparus aurata. Our observations indicate that, depending on the type of sequence, the chromatin has different properties with regard to anchorage to the SC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009283321632
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  • 8
    Electronic Resource
    Electronic Resource
    The evolution of the ribosomal loci in the subgenusLeopoldia of the genusMuscari (Hyacinthaceae) (2000)
    Springer
    Plant systematics and evolution 221 (2000), S. 245-252 
    Details
    ISSN: 1615-6110
    Keywords: In situ hybridization ; evolution ; NOR ; rDNA ; Muscari
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the subgenusLeopoldia of the genusMuscari, M. comosum is an exceptional species because it presents the most asymmetrical karyotype of the group and because its only active NOR is located in the fifth chromosome pair, while in the other species it is located in the first or second chromosome pairs (all the species have 2n = 18 chromosomes). SinceM. comosum has a derived karyotype different from those of the other species of the group, the resulting question is whether, in the first and second chromosome pair of this species, ribosomal cistrons persist. Observations after fluorescence in situ hybridization (FISH) using rDNA probes indicate that there are indeed ribosomal loci in the first and second chromosome pairs of this species, although these loci are inactive with respect to nucleolus organization. The location of rDNA regions in another three species of the same genus (M. atlanticum, M. dionysicum andM. matritensis) provides a basis for examining the significance of these findings in relation to the evolution of the ribosomal loci in this genus. Our observations indicate that in the genusMuscari, the largest sites for rRNA genes are not necessarily active, and, therefore, the activation of these regions is not related to the number of copies but to a specific regulation mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01089296
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