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  • LUNAR AND PLANETARY EXPLORATION  (9)
  • Animals  (2)
  • Valinomycin  (2)
  • 1980-1984  (9)
  • 1975-1979  (4)
  • 1
    Electronic Resource
    Electronic Resource
    Kinetics of ion transport in lipid membranes induced by lysine-valinomycin and derivatives (1979)
    Springer
    European biophysics journal 6 (1979), S. 39-56 
    Details
    ISSN: 1432-1017
    Keywords: Lipid membranes ; Valinomycin ; Ion transport ; Fast kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Summary Lysine-valinomycin and two N∈-acyl derivatives are compared with respect to their potency to transport Rb+ ions across thin lipid membranes. Lysine-valinomycin acts as a neutral ion carrier only above a pH of about 7 of the aqueous solutions, while at lower pH the molecules seem to be positively charged due to a protonation of the ε-NH2 group of the lysine residue. A kinetic analysis based on voltage jump relaxation experiments and on the nonlinearity of the current-voltage characteristics showed that the conductance increment λ per carrier molecule for uncharged lysine-valinomycin is similar to that of natural valinomycin. The attachment of a rather bulky side group such as the dansyl or para-nitrobenzyloxycarbonyl group reduced λ by approximately one order of magnitude. Some of the relaxation data of the valinomycin analogues were influenced by an unspedfic relaxation of the pure lipid membrane. This structural relaxation represents a limitation to the possibility of analyzing specific transport systems in thin lipid membranes by the voltage jump or charge pulse techniques. It is shown that the time dependence of this structural relaxation — which was first published by Sargent (1975) — is at variance with a three capacitor equivalent circuit of the membrane, which was suggested by Coster and Smith (1974) on the basis of a.c. measurements. A modified equivalent circuit has been found to represent a satisfactory analogue for the current relaxation in the presence of valinomycin. It turned out, however, that such an equivalent circuit provides little insight into the molecular mechanism of transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00537594
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Optical and electrical studies on dansyllysine-valinomycin in thin lipid membranes (1976)
    Springer
    European biophysics journal 2 (1976), S. 119-137 
    Details
    ISSN: 1432-1017
    Keywords: Valinomycin ; Lipid membranes ; Fluorescence ; Relaxation methods
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Summary Dansyllysine-valinomycin, a fluorescent analogue of the ionophore valinomycin was synthesized and incorporated into black lipid membranes. Its concentration inside the membrane was measured fluorometrically and was also determined from electrical relaxation experiments, which were analyzed on the basis of a previously proposed carrier model. The results of both methods agreed within less than one order of magnitude. This appears satisfactory in view of the sources of error inherent in both procedures. A conductance increment per carrier molecule of about 3 · 10−17 Ω−1 was obtained for dansyllysine-valinomycin in diphytanoyllecithin membranes at 25
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00863705
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  • 3
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    Calcium regulation during stimulus-secretion coupling: continuous measurement of intracellular calcium activities (1980)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1980-07-25
    Description: Accurate measurements of intracellular calcium activities in salivary gland epithelial cells of the insect Phormia regina were obtained with microelectrodes in which N,N'-di(11-ethoxycarbonyl)undecyl-N,N'-4,5-tetramethyl-3,6-dioxaoctane diacid diamide wsa incorporated in a liquid membrane system. When calibrated in solutions approximating the ionic concentration of the cell interior, these microelectrodes gave rapid stable responses that were linear functions of the logarithm of calcium activities and were not affected by potassium, sodium and magnesium. Continuous monitoring of calcium activities during serotonin-induced saliva release provided direct evidence of hormonal influence on transmembrane calcium movement and spontaneous regulation of intracellular calcium by stimulated cells.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉O'Doherty, J -- Youmans, S J -- Armstrong, W M -- Stark, R J -- New York, N.Y. -- Science. 1980 Jul 25;209(4455):510-3.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7394518" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Biological Transport/drug effects ; Calcium/*metabolism ; Diptera/*metabolism ; Epithelium/metabolism ; Kinetics ; Magnesium/pharmacology ; Microelectrodes ; Salivary Glands/drug effects/*metabolism ; Serotonin/pharmacology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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    PAPER CURRENT
  • 4
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    Abnormal development of kitten retino-geniculate connectivity in the absence of action potentials (1982)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 1982-08-20
    Description: Action potentials were silenced in one eye of neonatal kittens by repeated intraocular injections of tetrodotoxin for 5 to 8 weeks. After tetrodotoxin blockade was allowed to wear off, receptive field properties of individual relay cells in the lateral geniculate nucleus were examined. The many ON-OFF and binocular fields found in the layers that receive input from the treated eye suggest that these cells had extremely abnormal retino-geniculate synaptic connections. These effects were different in kind from those seen after deprivation rearing that does not silence action potentials. Lack of action potential activity was concluded to lead to abnormal development in the central nervous system.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Archer, S M -- Dubin, M W -- Stark, L A -- 7F32 EY 05442/EY/NEI NIH HHS/ -- New York, N.Y. -- Science. 1982 Aug 20;217(4561):743-5.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7100921" target="_blank"〉PubMed〈/a〉
    Keywords: *Action Potentials ; Animals ; Animals, Newborn ; Cats/*growth & development ; Evoked Potentials, Visual ; Facial Nerve/*growth & development ; Geniculate Ganglion/*growth & development ; Optic Nerve/growth & development ; Retina/*growth & development ; Sensory Deprivation ; Synapses/physiology ; Tetrodotoxin/pharmacology ; Visual Pathways/*physiology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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    PAPER CURRENT
  • 5
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    New models for landform evolution on Io (1984)
    In:  CASI
    Details
    Publication Date: 2006-04-06
    Description: As part of the Galilean Satellites Mappers Program, the South Polar region of Io was studied. Examination of the Voyager images had led to reassessment of the possible mechanisms by which certain units were created or modified in this area. Specifically, analyses have focused on determining the relative age of the mountain material and on the process by which the layered plains material was eroded.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA. Washington Repts. of Planetary Geol. Program; p 32-33
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  • 6
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    Stratigraphy of Oceanus Procellarum basalts - Sources and styles of emplacement (1980)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The basaltic fill of Oceanus Procellarum has been formally subdivided into four lithostratigraphic formations: The Repsold Formation, the Telemann Formation, the Hermann Formation, and the Sharp Formation. The Repsold Formation is composed of high-Ti basalts and pyroclastic deposits with an estimated age of 3.75 + or - 0.05 b.y. and an estimated volume of about 2.1 x 10 to the 5th cu km. This is overlain by the Telemann Formation composed of very low-Ti basalts and pyroclastic deposits with an estimated age of 3.6 + or - 0.2 b.y. and a volume of 4.2 x 10 to the 5th cu km. The Hermann Formation, composed of intermediate basalts with an estimated age of 3.3 + or - 0.3 b.y., represents the next youngest unit with an estimated volume of 2.2 x 10 to the 5th cu km. The youngest materials in Procellarum are the medium-to-high-Ti basalts comprising the Sharp Formation with an estimated age of 2.7 + or - 0.7 b.y. and a volume of 1.8 x 10 to the 4th cu km.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 85; Nov. 10
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  • 7
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    Late high-titanium basalts of the western maria - Geology of the Flamsteed region of Oceanus Procellarum (1980)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: The evolution, geology, geochemistry and topology of the Flamsteed region of Oceanus Procellarum are examined, considering remote sensing data including multispectral images and spectral reflectance measurements along with crater degradation studies and radar backscatter. Seven spectrally distinct basaltic units ranging in age from 2.5 plus or minus 0.5 to 3.5 plus or minus 0.5 billion years have been identified. The earliest units of the mapped area are composed of highlands material and include partially flooded impact craters, and the oldest surface exposed mare basalts are very low Ti basalts of the Telemann formation.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 85; July 10
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  • 8
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    The evolution of the lunar Nectaris multiring basin (1981)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The paper begins by discussing the pre-Nectaris crust, the formation of the basin, its age and its geophysics. The pre-mare basalt deposits are categorized into smooth plains deposits, cratered and patterned plains, knobby terrain, and massifs, and the structure, chemical composition, and probable origin of these are discussed. Alternative scenarios for the formation of the plains are that they consist of impact melt ejecta, ejecta overlying smoothed-out preexisting topographic material, or ejecta overlying extrusive deposits. The mare deposits are assessed in terms of their composition, basalt ages and thickness, and eruption styles. A probable age of 3.6 billion years for the basalts is given. The tectonics of mare ridges and fractures and floor-fractured craters are gone into. Post-mare cratering is also discussed. It is concluded that the morphology of multiring basins is strongly dependent on lithosphere thickness.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus; 48; Dec. 198
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  • 9
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    Tharsis volcanoes - Separation distances, relative ages, sizes, morphologies, and depths of burial (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Network analysis indicates the separation distances of the Tharsis volcanoes to be 700 to 900 km; this is considered to be the thickness of the Tharsis thermal lithosphere or 'tectosphere' which has thickened with time. Although as a whole the Tharsis volcanoes exhibit a random distribution, preferential alignments emerge when the history of the region is divided into separate periods. The preferential alignments mimic those of fractures in the surrounding terrain. Photogeologic and morphometric data indicate that the volcanoes fall into four distinct classes: montes, tholi, paterae, and a class whose sole representative is Alba Patera. The volcanoes have been buried by lava up to about 4 km in thickness. The sizes of the volcanoes directly correlate with their separation distances from their nearest neighbors. It is concluded that the greater the lithosphere thickness, the larger will be the volcano and the greater its separation distance from its nearest neighbor.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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  • 10
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    A preliminary analysis of lunar extra-mare basalts - Distribution, compositions, ages, volumes, and eruption styles (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Extra-mare basalts occupy 8.5% of the lunar basalt area and comprise 1% of the total mare basalt volume. They are preferentially located where the crust is thin and topographically low. In terms of age, eruption style, and composition they are as variable as the mare basalts. In some instances extrusion in extra-mare craters was preceded by floor-fracturing whereas in other cases it apparently was not. The volume of lava erupted may have been controlled more by the volume of magma produced than by hydrostatic effects. A minimum of nearly 1300 separate basalt eruptions is indicated; the true value could be nearer 30,000 separate eruptions.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Moon and the Planets; 26; May 1982
    Format: text
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