Search Results - (Author, Cooperation:L. Contreras)

Showing 1 - 19 results of 19, query time: 0.24s Refine Results
  1. 1
    Staff View
    Publication Date:
    2012-08-04
    Publisher:
    Nature Publishing Group (NPG)
    Print ISSN:
    0028-0836
    Electronic ISSN:
    1476-4687
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    Animals ; Antarctic Regions ; Atmosphere/chemistry ; Carbon Dioxide/analysis ; Cell Respiration ; Ecosystem ; Geologic Sediments/chemistry ; Greenhouse Effect/*history ; History, Ancient ; Human Activities ; Lipids/analysis ; Models, Theoretical ; Photosynthesis ; Pollen ; Reproducibility of Results ; Seasons ; Spores/isolation & purification ; *Temperature ; Trees/growth & development ; *Tropical Climate
    Published by:
    http://www.nature.com/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    J. L. Contreras ; J. H. Reichman
    American Association for the Advancement of Science (AAAS)
    Published 2015
    Staff View
    Publication Date:
    2015-12-15
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    Access to Information ; Information Dissemination/*legislation & jurisprudence ; *Intellectual Property
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  3. 3
    J. Aleksic ; S. Ansoldi ; L. A. Antonelli ; P. Antoranz ; A. Babic ; P. Bangale ; J. A. Barrio ; J. Becerra Gonzalez ; W. Bednarek ; E. Bernardini ; B. Biasuzzi ; A. Biland ; O. Blanch ; S. Bonnefoy ; G. Bonnoli ; F. Borracci ; T. Bretz ; E. Carmona ; A. Carosi ; P. Colin ; E. Colombo ; J. L. Contreras ; J. Cortina ; S. Covino ; P. Da Vela ; F. Dazzi ; A. De Angelis ; G. De Caneva ; B. De Lotto ; E. de Ona Wilhelmi ; C. Delgado Mendez ; D. Dominis Prester ; D. Dorner ; M. Doro ; S. Einecke ; D. Eisenacher ; D. Elsaesser ; M. V. Fonseca ; L. Font ; K. Frantzen ; C. Fruck ; D. Galindo ; R. J. Garcia Lopez ; M. Garczarczyk ; D. Garrido Terrats ; M. Gaug ; N. Godinovic ; A. Gonzalez Munoz ; S. R. Gozzini ; D. Hadasch ; Y. Hanabata ; M. Hayashida ; J. Herrera ; D. Hildebrand ; J. Hose ; D. Hrupec ; W. Idec ; V. Kadenius ; H. Kellermann ; K. Kodani ; Y. Konno ; J. Krause ; H. Kubo ; J. Kushida ; A. La Barbera ; D. Lelas ; N. Lewandowska ; E. Lindfors ; S. Lombardi ; F. Longo ; M. Lopez ; R. Lopez-Coto ; A. Lopez-Oramas ; E. Lorenz ; I. Lozano ; M. Makariev ; K. Mallot ; G. Maneva ; N. Mankuzhiyil ; K. Mannheim ; L. Maraschi ; B. Marcote ; M. Mariotti ; M. Martinez ; D. Mazin ; U. Menzel ; J. M. Miranda ; R. Mirzoyan ; A. Moralejo ; P. Munar-Adrover ; D. Nakajima ; A. Niedzwiecki ; K. Nilsson ; K. Nishijima ; K. Noda ; R. Orito ; A. Overkemping ; S. Paiano ; M. Palatiello ; D. Paneque ; R. Paoletti ; J. M. Paredes ; X. Paredes-Fortuny ; M. Persic ; J. Poutanen ; P. G. Prada Moroni ; E. Prandini ; I. Puljak ; R. Reinthal ; W. Rhode ; M. Ribo ; J. Rico ; J. Rodriguez Garcia ; S. Rugamer ; T. Saito ; K. Saito ; K. Satalecka ; V. Scalzotto ; V. Scapin ; C. Schultz ; T. Schweizer ; S. N. Shore ; A. Sillanpaa ; J. Sitarek ; I. Snidaric ; D. Sobczynska ; F. Spanier ; V. Stamatescu ; A. Stamerra ; T. Steinbring ; J. Storz ; M. Strzys ; L. Takalo ; H. Takami ; F. Tavecchio ; P. Temnikov ; T. Terzic ; D. Tescaro ; M. Teshima ; J. Thaele ; O. Tibolla ; D. F. Torres ; T. Toyama ; A. Treves ; M. Uellenbeck ; P. Vogler ; R. Zanin ; M. Kadler ; R. Schulz ; E. Ros ; U. Bach ; F. Krauss ; J. Wilms
    American Association for the Advancement of Science (AAAS)
    Published 2014
    Staff View
    Publication Date:
    2014-11-08
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    http://www.aaas.org/

    Latest Papers from Table of Contents or Articles in Press
  4. 4
    Baquedano, J. A. ; Contreras, L. ; Diéguez, E. ; Cabrera, J. M.

    [S.l.] : American Institute of Physics (AIP)
    Published 1989
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    A holographic method similar to that previously used with LiNbO3 to study the spectral behavior of photorefractive centers has been applied to Bi12SiO20 (BSO) and Bi12GeO20 (BGO). By erasing with incoherent light a previously written grating, measurements of the grating decay constants as a function of the erasing wavelength have been carried out. The grating erasure exhibits decays made up of a sum of two exponential terms for all wavelengths between 390 and 620 nm. In terms of recent photorefractive models which use two active species, our results imply that there exist two different photorefractive centers in BGO and BSO. By numerically fitting the observed spectral dependencies of the decay constants to the model equations, the absorption bands associated to these centers have been obtained. Their peak positions and half-widths are the following: 2.7 eV (0.27 eV) and 3.1 eV (0.4 eV) for BSO; 2.8 eV (0.3 eV) and 3.1 eV (0.4 eV) for BGO.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.343748

    Articles: DFG German National Licenses
  5. 5
    Mora, A. ; Belchi, J. ; Contreras, L. ; Rubio, G.

    Oxford, UK : Munksgaard International Publishers
    Published 2002
    Staff View
    ISSN:
    1600-0536
    Source:
    Blackwell Publishing Journal Backfiles 1879-2005
    Topics:
    Medicine
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1034/j.1600-0536.2002.470308_14.x

    Articles: DFG German National Licenses
  6. 6
    Staff View
    ISSN:
    0003-9861
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1016/0003-9861(92)90527-4

    Articles: DFG German National Licenses
  7. 7
    Staff View
    ISSN:
    0022-328X
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Chemistry and Pharmacology
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0022-328X(93)80411-4

    Articles: DFG German National Licenses
  8. 8
    Staff View
    ISSN:
    0022-328X
    Keywords:
    Barium ; Calcium ; Poly(pyrazolyl)borates ; Strontium ; X-ray structure
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Chemistry and Pharmacology
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/0022-328X(94)84072-5

    Articles: DFG German National Licenses
  9. 9
    Chiang, L. ; Contreras, L. ; Chiang, J. ; Ward, P.H.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0003-9861
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1016/0003-9861(81)90158-2

    Articles: DFG German National Licenses
  10. 10
    Staff View
    ISSN:
    0006-291X
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1016/0006-291X(89)92627-2

    Articles: DFG German National Licenses
  11. 11
    Woldegiorgis, G. ; Contreras, L. ; Shrago, E.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0006-291X
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Chemistry and Pharmacology
    Physics
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1016/0006-291X(90)90337-M

    Articles: DFG German National Licenses
  12. 12
    Contreras, L. ; Slemon, C.E. ; MacLean, D.B.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0040-4039
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Chemistry and Pharmacology
    Type of Medium:
    Electronic Resource
    URL:
    http://linkinghub.elsevier.com/retrieve/pii/S0040-4039(01)95190-1

    Articles: DFG German National Licenses
  13. 13
    Staff View
    ISSN:
    1420-9071
    Keywords:
    Rodent ; hystricognath ; octodontid ; chromosome ; karyology ; heterochromatin
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Medicine
    Notes:
    Summary Tympanoctomys barrerae, a desert specialist member of the family Octodontidae, until now thought to be conservative, and ancestral to South American hystricognath rodents, presents the highest diploid chromosome number (2n=102) known in a mammal. Unexpectedly, its karyotype was found to be composed mainly of metacentric to sub-metacentric chromosomes. Mechanisms by which such a karyotype may have been derived are discussed.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF01954248

    Articles: DFG German National Licenses
  14. 14
    Staff View
    ISSN:
    1432-1939
    Keywords:
    Key words Herbivory ; Predation ; Tritrophic effects ; Ephemeral plants ; Chilean semiarid zone
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Notes:
    Abstract  We monitored the cover and seed bank response of shrubs, perennial herbs, and ephemeral plants to experimental exclusion of both the principal rodent herbivore, Octodon degus, and its vertebrate predators from 1989 to 1994 in a semiarid Chilean mediterranean site. Although both richness and species composition of the plant community at the study site were largely determined by abiotic factors (mainly rainfall and soil nutrients), predator and herbivore exclusion had significant effects on the relative abundance of several plant species. Experimental exclusion of herbivores was associated with increased cover of some shrubs and a perennial grass, and decreased cover and seed densities of several ephemerals, especially those exotic or restricted to areas underneath shrubs. Herbivores apparently reduced shrubs through browsing and indirectly affected herb cover and seed densities by opening up areas under shrubs and/or modifying physical and chemical conditions of the soil. Plant responses to predator exclusion were less clear. Nevertheless, higher cover of some shrubs and ephemerals in the presence of predators suggests tritrophic effects through changes in small mammal densities and/or foraging behavior.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/s004420050099

    Articles: DFG German National Licenses
  15. 15
    Staff View
    ISSN:
    1573-4838
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Medicine
    Technology
    Notes:
    Abstract Since the short-term, acute scarring process induced by a biomaterial may condition the evolution of the repair process, the present investigation evaluates the behavior of polytetrafluoroethylene (PTFE) and polypropylene (PL) biomaterials in the initial stages of repair. Three PTFE biomaterials (Mycro Mesh®, Dual Mesh® and Soft Tissue Patch®) and one PL biomaterial (Marlex®) were employed to repair defects created in the abdominal wall of New Zealand rabbits. Animals were sacrificed at 3 or 7 days. Specimens were obtained for light and scanning electron microscopy, and immunohistochemical analysis using the RAM-11 monoclonal antibody for rabbit macrophages. The PL implants showed substantial adhesion formation with viscera. Lower adhesion formation was detected in the PTFE implants. The evolution of the acute phase of the repair process was similar for each PTFE biomaterial. At 3 days post implant, an incipient neoperitoneum was detected which was fully established after 7 days. The behavior of the PL implant was similar, although a greater amount of reticular granulation was detected. The neoformed peritoneum was irregular. Few RAM-11-labeled macrophages were detected in all cases. The acute phase of the tissue repair process induced by the implant of PTFE and PL biomaterials generally proceeds along similar lines to a normal repair process. However, the use of microporous, laminar materials seems to favor the early establishment of a well-defined neoperitoneal layer.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1023/A:1008981517743

    Articles: DFG German National Licenses
  16. 16
    Staff View
    ISSN:
    1573-4838
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Medicine
    Technology
    Notes:
    Abstract Comparisons were made of the tissue response to the implantation of two different polytetrafluoroethylene prostheses: Soft Tissue Patch (STP) and Mycro Mesh (MM). A 7 × 5 cm prosthesis of STP (n=12) or MM (n=12) was implanted into a defect of the same size (involving all layers except skin) created in the anterior abdominal wall in 24 New Zealand rabbits. The prostheses were anchored to the recipient tissue, in direct contact with the intestinal loops and connective tissue. After 14, 30, 60 and 90 days, groups of six implants were studied macroscopically and samples were taken to be processed by light microscopy, scanning electron microscopy (SEM), immunohistochemical studies and tensiometry. All animals were valid for the study. In three cases STP implants presented very loose adhesions in the peripheral zones corresponding to the sutures. They were also observed on three MM implants, in the area of the perforations. Light and scanning microscopy revealed the formation of a capsule of scar tissue surrounding both types of prosthesis. At day 90, bridges of connective tissue had formed in the perforated areas of MM. Good vascularization was established in the areas of recipient tissue corresponding to both implants. The macrophage reaction to both biomaterials was maximal at 14 days, after which it progressively decreased until day 90. Tensile testing revealed no significant differences between the two biomaterials. It is concluded that (a) behaviour in the peritoneal interface is similar in the two prostheses, (b) both biomaterials become encapsulated rather than integrated into the recipient tissue, (c) the foreign body reaction does not determine the success or failure of the implants, (d) The perforations of the MM prosthesis do not increase its resistance to stress, or at least not after 90 days of implantation into rabbit abdominal wall.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00705428

    Articles: DFG German National Licenses
  17. 17
    Bellón, J. M. ; Buján, J. ; Contreras, L. ; Hernando, A.
    Springer
    Published 1996
    Staff View
    ISSN:
    1573-4838
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Medicine
    Technology
    Notes:
    Abstract The objective of this work was to study the healing process at the interface between biomaterial and visceral peritoneum. Implants of polytetrafluoroethylene (ePTFE) and polypropylene prostheses were introduced into the abdominal wall of New Zealand rabbits. The behaviour of the biomaterials was analysed using light and scanning electron microscopy and immunohistochemistry in which a specific anti-rabbit macrophage monoclonal antibody (RAM 11) was employed. According to macroscopic observation, there was significantly fewer adhesions prosthesis-viscera to ePTFE than to polypropylene implants. After ePTFE implantation, restoration of the peritoneum took place in an orderly fashion. When polypropylene was used, the peritoneum formed was a disorderly tissue in which small areas of haemorrhage and necrosis could be seen to coincide with the appearance of adhesions. The number of labelled macrophages peaked 14 days after ePTFE or polypropylene implantation, after which it decreased gradually. It is concluded that, given the low rate of adhesion provoked by PTFE, this material is ideal for implants contiguous to the peritoneal cavity viscera. The macrophage response does not determine the use of one material or the other. The structure of the newly formed peritoneum and development of adhesions depends on the porosity of the biomaterial.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF00154544

    Articles: DFG German National Licenses
  18. 18
    Bellón, J. M. ; Buján, J. ; Contreras, L. A. ; Hernando, A. ; Jurado, F.

    Hoboken, NJ : Wiley-Blackwell
    Published 1996
    Staff View
    ISSN:
    0021-9304
    Keywords:
    Chemistry ; Polymer and Materials Science
    Source:
    Wiley InterScience Backfile Collection 1832-2000
    Topics:
    Medicine
    Technology
    Notes:
    The biomaterial ePTFE is widely used in the clinical environment for vascular replacement or bypass, as well as in the repair of tissue defects, especially those involving the abdominal wall. The objective of this study was to evaluate the healing response to ePTFE prostheses implanted into a circulatory interface and a tissue interface, each in a different animal species. For vascular implants, the Sprague - Dawley rat (n = 60) was used, while the New Zealand white rabbit (n = 20) was used in the tissue replacement model. In the former, a vascular microprosthesis measuring 5 mm in length and 1 mm in internal diameter, having a porosity of 30 μm, was implanted into the common iliac artery. In the rabbit, a 7 × 5-cm fragment of ePTFE (Soft-Tissue Patch) was implanted into a defect in anterior abdominal wall that involved all the tissue layers. In this case, the prosthesis was left touching the intestinal loops. The implants were studied between 14 and 90 days of postimplantation by means of light microscopy, scanning electron microscopy, and immunohistochemistry. The latter involved the use of anti-rat (MAC-341) and anti-rabbit (RAM-11) macrophage-specific monoclonal antibodies. The behavior of the ePTFE in the different interfaces (vascular and abdominal wall) was similar with respect to the following aspects: the prosthesis presented a process of encapsulation which was more intense on the outer surface; colonization of the implant was limited to the outermost two thirds, with minimal invasion of the middle portion; colonization was absent on the edges of the prosthesis; collagenization of the interstice of the mesh occurred late; the foreign body reaction taking place on the outer surface was similar in both interfaces, with formation of a barrier consisting of macrophages and giant cells that did not penetrate the prosthesis; and, finally, in neither of the two models was vascular colonization of the PTFE prosthesis observed; rather, the angiogenic process was limited to the periprosthetic zones. The integration of the implant made of ePTFE is similar despite the differences in interfaces and the use of different animal species. The macrophage response does not determine the success or failure of the implant. © 1996 John Wiley & Sons, Inc.
    Additional Material:
    10 Ill.
    Type of Medium:
    Electronic Resource

    Articles: DFG German National Licenses
  19. 19
    Prieto, C. ; Pelous, J. ; Boissier, M. ; Contreras, L.

    Chichester [u.a.] : Wiley-Blackwell
    Published 1989
    Staff View
    ISSN:
    0377-0486
    Keywords:
    Chemistry ; Analytical Chemistry and Spectroscopy
    Source:
    Wiley InterScience Backfile Collection 1832-2000
    Topics:
    Chemistry and Pharmacology
    Physics
    Notes:
    Brillouin scattering was performed between 80 and 300 K in order to study the hypersonic properties of Bi4 Ge3O12 crystals. The velocity and the attenuation of longitudinal acoustic phonons propagating along the [100] direction were measured for frequencies near 34 GHz. The Brillouin shift shows a variation with temperature which is five times lower than that observed in another bismuth germanium oxide, Bi12 GeO20. The hypersound attenuation is also very low and seems to be independent of temperature.
    Additional Material:
    1 Ill.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1002/jrs.1250200309

    Articles: DFG German National Licenses