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  • Alnus rubra  (1)
  • Cross-Sectional Studies  (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
Collection
Keywords
Publisher
  • American Association for the Advancement of Science (AAAS)  (2)
  • Springer  (2)
  • EMBO Press
  • Periodicals Archive Online (PAO)
Years
  • 1985-1989  (4)
  • 1965-1969
Year
  • 1
    ISSN: 1572-879X
    Keywords: Electrochemical oxidation ; alkenoic acids on platinum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: 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).
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 118 (1989), S. 205-209 
    ISSN: 1573-5036
    Keywords: actinorhizal ; Alnus rubra ; auxin ; Frankia ; IAA ; indole-3-acetic acid ; indole-3-ethanol ; nodule secretion ; phytohormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
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  • 3
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1989-07-07
    Description: 〈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〉
    Keywords: Diabetes Mellitus/*physiopathology ; Humans ; Insulin/*physiology ; Insulin Resistance
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 4
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1987-07-10
    Description: 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〉
    Keywords: 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
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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