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  • Alnus rubra  (1)
  • Diabetes Mellitus/*physiopathology  (1)
  • Electrochemical oxidation  (1)
  • Grief  (1)
  • American Association for the Advancement of Science (AAAS)  (2)
  • Springer  (2)
  • EMBO Press
  • Periodicals Archive Online (PAO)
  • 1985-1989  (4)
  • 1965-1969
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Schlagwörter
Verlag/Herausgeber
  • American Association for the Advancement of Science (AAAS)  (2)
  • Springer  (2)
  • EMBO Press
  • Periodicals Archive Online (PAO)
Erscheinungszeitraum
  • 1985-1989  (4)
  • 1965-1969
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  • 1
    Digitale Medien
    Digitale Medien
    Electrochemical oxidation of adsorbed alkenoic acids as a function of chain length at Pt(111) electrodes. Studies by cyclic voltammetry, EELS and Auger spectroscopy (1989)
    Springer
    Catalysis letters 3 (1989), S. 275-297 
    Details
    ISSN: 1572-879X
    Schlagwort(e): Electrochemical oxidation ; alkenoic acids on platinum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Studies of the electrochemical oxidation of a series of straight-chain terminal alkenoic acids adsorbed at a Pt(111) electrode surface are reported. Compounds adsorbed were: propenoic acid (acrylic acid, PPA); 3-butenoic acid (vinylacetic acid, 3BTA); 4-pentenoic acid (allylacetic acid, 4PTA); 6-heptenoic acid (6HPA); and 10-undecenoic acid (10UDA). Vibrational spectra of adsorbed layers were obtained by use of electron energy-loss spectroscopy (EELS). Molecular packing densities were measured by use of Auger spectroscopy. Electrochemical oxidation of each adsorbed layer was explored by means of cyclic voltammetry in aqueous inert electrolyte (KF/HF). As the analogous aliphatic acids are not chemisorbed at Pt under the same conditions, the alkenoic acids evidently adsorb at Pt(111) predominantly through the C=C double bond. Molecular packing densities indicate that the carboxylic acid moiety is in contact with the Pt surface only in the case of PPA. EELS spectra also indicate that the carboxylate groups (other than in PPA) are present as pendants. The carboxylic acid O-H stretching bands of most of the adsorbed acids are red-shifted and broadened, evidently due to extensive intermolecular hydrogen bonding; the exceptions are PPA, for which the interaction is primarily with the Pt surface, and 3BTA, for which intermolecular interaction between the carboxylic acid pendants is apparently prevented by steric considerations. The surface-attached carboxylic acid moieties react with KOH solution, leading to retention of K+ ions, detected by Auger spectroscopy, and to changes in the vibrational spectra indicative of carboxylate anions; reactivity toward KOH decreases with chain length. Adsorbed alkenoic acids at Pt(111) surfaces are stable in water and in vacuum. Oxidation of the adsorbed short-chain acids PPA and 3BTA proceeds to completion, forming CO2 as the principal product. Oxidation of the adsorbed long-chain acids converts the C=C moiety to 2CO2, and transforms the remainder of the molecule to an unadsorbed diacid (likely possibilities are malonic acid from 4PTA; glutaric acid from 6HPA; and heptane-1,7-dioic acid from 10UDA).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00766066
    Standort Signatur Erwartet Verfügbarkeit
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    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    Identification of indole compounds secreted byFrankia HFPArI3 in defined culture medium (1989)
    Springer
    Plant and soil 118 (1989), S. 205-209 
    Details
    ISSN: 1573-5036
    Schlagwort(e): actinorhizal ; Alnus rubra ; auxin ; Frankia ; IAA ; indole-3-acetic acid ; indole-3-ethanol ; nodule secretion ; phytohormone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Indole compounds secreted byFrankia sp. HFPArI3 in defined culture medium were identified with gas chromatography-mass spectrometry (GC-MS). WhenFrankia was grown in the presence of13C(ring-labelled)-L-tryptophan,13C-labelled indole-3-acetic acid (IAA), indole-3-ethanol (IEtOH), indole-3-lactic acid (ILA), and indole-3-methanol (IMeOH) were identified. High performance liquid chromatography (HPLC) and GC-MS with selected ion monitoring were used to quantify levels of IAA and IEtOH inFrankia culture medium. IEtOH was present in greater abundance than IAA in every experiment. When no exogenous trp was supplied, no or only low levels of indole compounds were detected. Seedling roots ofAlnus rubra incubated in axenic conditions in the presence of indole-3-ethanol formed more lateral roots than untreated plants, indicating that IEtOH is utilized by the host plant, with physiological effects that modify patterns of root primordium initiation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02232808
    Standort Signatur Erwartet Verfügbarkeit
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    Artikel (Nationallizenzen)
    Volltext
  • 3
    facet.materialart.
    Unbekannt
    Molecular defects in insulin action (1989)
    American Association for the Advancement of Science (AAAS)
    Details
    Publikationsdatum: 1989-07-07
    Beschreibung: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kahn, C R -- Goldstein, B J -- New York, N.Y. -- Science. 1989 Jul 7;245(4913):13.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2662406" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Diabetes Mellitus/*physiopathology ; Humans ; Insulin/*physiology ; Insulin Resistance
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
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    Unbekannt
    Human aging: usual and successful (1987)
    American Association for the Advancement of Science (AAAS)
    Details
    Publikationsdatum: 1987-07-10
    Beschreibung: Research in aging has emphasized average age-related losses and neglected the substantial heterogeneity of older persons. The effects of the aging process itself have been exaggerated, and the modifying effects of diet, exercise, personal habits, and psychosocial factors underestimated. Within the category of normal aging, a distinction can be made between usual aging, in which extrinsic factors heighten the effects of aging alone, and successful aging, in which extrinsic factors play a neutral or positive role. Research on the risks associated with usual aging and strategies to modify them should help elucidate how a transition from usual to successful aging can be facilitated.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rowe, J W -- Kahn, R L -- New York, N.Y. -- Science. 1987 Jul 10;237(4811):143-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3299702" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Aged ; Aged, 80 and over ; *Aging/metabolism/physiology/psychology ; Carbohydrate Metabolism ; Cognition ; Cross-Sectional Studies ; Grief ; Health Promotion ; Health Services for the Aged ; Humans ; Longitudinal Studies ; Osteoporosis/physiopathology ; Patient Acceptance of Health Care ; Reference Values ; Social Support ; Volition
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
    Standort Signatur Erwartet Verfügbarkeit
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    AKTUELLE ARTIKEL
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