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  • 1
    Electronic Resource
    Electronic Resource
    Operators with closed range (1967)
    Springer
    Mathematische Annalen 174 (1967), S. 278-284 
    Details
    ISSN: 1432-1807
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01364274
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  • 2
    Electronic Resource
    Electronic Resource
    On a generalised open-mapping theorem (1967)
    Springer
    Mathematische Annalen 172 (1967), S. 217-221 
    Details
    ISSN: 1432-1807
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01351188
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  • 3
    Electronic Resource
    Electronic Resource
    The structure of the chromosomes in human primordial oocytes (1967)
    Springer
    Chromosoma 22 (1967), S. 358-377 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Primordial oocytes (oocytes in primordial follicles) from human ovaries aged 51/2 months post conception to 11 3/4 years post partum were examined in: (a) squash preparations of fresh and fixed tissue; (b) histological preparations; and (c) thin sections by electron microscopy, in order to study the structure of the chromosomes. — The light microscope shows that the chromosome consists of a thread bearing numerous fine lateral appendages. Cytochemical tests indicate that the thread contains DNA, and is surrounded by material containing RNA and protein. — The electron microscope shows that there are three main structural components in the chromosome: (i) an axis or “core” containing at least two longitudinal strands about 200 Å thick; (ii) a surrounding sheath composed of coiled fibrils which form symmetrically arranged columns and loops, and (iii) clusters of large granules which are associated with the outer parts of the sheath. Small nucleoli and other granular bodies are also present. — These observations indicate the presence of lampbrush chromosomes in the human oocyte. The significance of this type of chromosome in mammals is discussed in relation to the differential radiosensitivity of the oocytes, and to the form of chromosomes at the dictyate stage in rodents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00319880
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  • 4
    Electronic Resource
    Electronic Resource
    The alteration of olivine in basaltic and associated lavas (1967)
    Springer
    Contributions to mineralogy and petrology 16 (1967), S. 258-273 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Olivines which cool under oxidizing conditions exsolve iron oxides at high temperature, and at low temperatures break down to essentially chloritic materials. Olivines which cool under non-oxidizing conditions alter at intermediate temperatures to complex assemblages of chlorite and interstratified phyllosilicates containing a smectite. Alteration under oxidizing conditions at low temperature, probably below 140° C, produces “iddingsite”, an orientated assemblage of goethite and interstratified phyllosilicates also containing a smectite. Post-deuteric alteration extends or initiates the breakdown of olivine to phyllosilicate mixtures often resulting in widespread movement of materials through the flow. Post-deuteric alteration of “iddingsite” produces strongly pleochroic, highly ordered varieties which eventually break down to green phyllosilicate assemblages. Weathering of olivine may produce orientated assemblages similar to deuteric forms of “iddingsite”. Weathering of green alteration products results in oxidation and the liberation of discrete iron hydroxides. Alteration in all cases requires exchange of material between interstitial components and olivine. During deuteric alteration, plagioclase and pyroxene are usually unaffected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371095
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  • 5
    Electronic Resource
    Electronic Resource
    The alteration of olivine in basaltic and associated lavas (1967)
    Springer
    Contributions to mineralogy and petrology 16 (1967), S. 233-257 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract A study of the alteration products of olivines in lavas from a number of volcanic regions indicates the temperature and oxidation conditions under which deuteric alteration has taken place. High temperature oxidation of basaltic olivine results in either exsolution of hematite associated with a more forsteritic olivine, or formation of a symplectic intergrowth of magnetite and orthopyroxene. Continued oxidation of the metastable assemblage magnetite + orthopyroxene produces hematite+forsterite. Identical textures and mineralogical assemblages have been produced in a number of heating experiments, and compare closely with natural examples, and with reheated olivines from gabbroic and ultra-basic xenoliths. The advanced oxidation state of coexisting Fe-Ti oxides associated with highly altered olivines confirms the suggestion that processes of oxidation are the prime causes of high temperature deuteric alteration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371094
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  • 6
    Electronic Resource
    Electronic Resource
    Non-embeddable functions with a fixpoint of multiplier 1 (1967)
    Springer
    Mathematische Zeitschrift 99 (1967), S. 377-384 
    Details
    ISSN: 1432-1823
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01111016
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  • 7
    Electronic Resource
    Electronic Resource
    The origin of variation in “wild”Raphanus sativus (Cruciferae) in California (1967)
    Springer
    Genetica 38 (1967), S. 243-274 
    Details
    ISSN: 1573-6857
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Analyses of populations ofRaphanus growing in the central part of California, from the Sierra Nevada foothills to the Pacific coast, show that pureR. raphanistrum can be found only in the Central Valley, while over the remainder of the area populations of the so-called “wild” (weedy)R. sativus occur. More detailed morphological studies of a number of populations in this area have revealed that the populations of “wild”R. sativus originated by hybridization of the cultivated forms of this species (the radish) with another introduced species, already a weed,R. raphanistrum. The composition of each hybrid population with respect to the proportion of characters of the one or the other species depends upon the habitat it occupies and its geographic location. Populations in inland areas display a high proportion ofR. raphanistrum characters, while in those near the coastR. sativus characters predominate. Artificial hybrids betweenR. raphanistrum and a cultivated form ofR. sativus exhibited about 50% pollen fertility and were heterozygous for a reciprocal translocation. Examination of “wild” populations ofR. sativus revealed that plants heterozygous for a reciprocal translocation are present in varying proportions. Experimental evidence is produced to show that this translocation is identical with that separatingraphanistrum from cultivated forms ofsativus. Thus a cytological proof of the introgression is added to the morphological evidence. Introgression ofraphanistrum characters appears to have been a major factor in converting the erstwhile crop plant,R. sativus, into a highly successful weed in California.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01507462
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  • 8
    Electronic Resource
    Electronic Resource
    UV-Induced enhancement of recombination among lambda bacteriophages in UV-sensitive host bacteria (1967)
    Springer
    Molecular genetics and genomics 100 (1967), S. 166-177 
    Details
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The UV enhancement of recombination among λ bacteriophages was studied in host bacteria that are defective in DNA repair and compared to that observed in wild type host strains. The following conclusions were drawn: 1. The UV enhancement of recombination is even greater in HCR− than in HCR+ host strains. The UV lesions that promote recombination are repaired by host cell reactivation with the same efficiency as are potentially lethal UV lesions. 2. The UV enhancement of λ recombination is the same in HCR+ host strains that are deficient in their own recombination as it is in the wild type hosts. 3. Very few lesions per phage particle are sufficient to stimulate the enhanced recombination. The UV-stimulated recombination occurs during the same time interval as host cell reactivation. 4. There is substantial multiplicity reactivation of UV lesions in λ. Similar numbers of recombination events neutralize similar numbers of UV lesions in HCR+ and HCR− hosts, but a much greater survival increase is observed in the latter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00333603
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  • 9
    Electronic Resource
    Electronic Resource
    The specific resistance of biological material—A compendium of data for the biomedical engineer and physiologist (1967)
    Springer
    Medical & biological engineering & computing 5 (1967), S. 271-293 
    Details
    ISSN: 1741-0444
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Description / Table of Contents: Sommaire Cet article présente l'historique et les résultats de lévaluation de la résistivité électrique du sang et d'autres liquides biologiques, du muscle cardiaque, des muscles du squelette, des poumons, des reins, du foie, de la vesicule biliaire, du pancréas, des tissus nerveux, des vaisseaux, des os et de divers autres tissus. On indique les conditions de mesure lorsque cela est possible.
    Abstract: Zusammenfassung In diser Arbeit wird die historische Entwicklung der Bestimmung des elektrischen Widerstands beschrieben. Tabellierte Daten für den elektrischen Widerstand von Blut, anderen Körperflüssigkeiten, Herzmuskel, Skelettmuskel, Lunge, Niere, Leber, Milz, Pankreas, Nervengewebe, Fett, Knochen und verschiedenen anderen Geweben werden zusammengestellt. Wenn möglich, werden die Meßbedingungen angegeben.
    Notes: Abstract The paper traces the history of, and tabulates determinations of the electrical resistivity of blood, other body fluids, cardiac muscle, skeletal muscle, lung, kidney, liver, spleen, pancreas, nervous tissue, fat, bone, and other miscellaneous tissues. Where possible, the conditions of measurement are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02474537
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  • 10
    Electronic Resource
    Electronic Resource
    The relationship between electrode area and amplifier input impedance in recording muscle action potentials (1967)
    Springer
    Medical & biological engineering & computing 5 (1967), S. 561-569 
    Details
    ISSN: 1741-0444
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Description / Table of Contents: Sommaire Lorsqu’il est nécessaire de connaître la nature fondamentale d’un phénomène d’origine bioélectrique, on fait appel généralement à une microélectrode connectée à un amplificateur à haute impédance d’entrée. Les micropipettes en verre sont employées aussi bien que les microélectrodes métalliques. Bien que des précautions spéciales soient respectées pour l’usage des micropipettes, on fait d’ordinaire moins attention à l’impédance d’entrée des amplificateurs lors de l’emploi des microélectrodes métalliques, partant du principe que l’impédance de celles-ci est beaucoup plus faible que celle des micropipettes de taille comparable. Ce principle conduit à conclure que la plupart des amplificateurs d’enregistrement des phénomènes bioélectriques peuvent être utilisés en liaison avec des microélectrodes métalliques. Le but de cet article est de montrer l’influence de la surface des microélectrodes métalliques sur la distorsion du signal, enregistré à l’aide d’un amplificateur à impédance résistive commutable. On verra également qu’il existe une relation entre l’aire de la microélectrode et l’impédance d’entrée pour differents taux de distorsion. Dans un article antérieur (Geddes et Baker, 1966) on présentait une telle relation à l’occasion d’enregistrement d’électrocardiogrammes avec de petites électrodes. L’étude présente tendant à préciser cette relation a été faite à partir de l’électomyogramme du gastroenémius de grenouille.
    Abstract: Zusammenfassung Sollen die grundsätzlichen Eigenschaften eines bioelektrischen Vorgangs untersucht werden, benutzt man gewöhnlich eine Mikroelektrode, die mit einem Verstärker von sehr hoher Eingangsimpedanz verbunden ist. Glasmikropipetten und Metallmikroelektroden werden zu diesem Zweck routinemäßig eingesetzt. Obwohl beim Gebrauch von Mikropipetten besondere Vorsichtsmaßnahmen getroffen werden, wird beim Gebrauch von Metallmikroelektroden der Verstärkeriengangsimpedanz weniger Beachtung geschenkt. Es wird nämlich angenommen, daß die Impedanz der Metallelektroden beträchtlich unter der von Mikropipetten ähnlicher Größe liegt. Diese Annahme führt oft zu dem Schluß, daß die meisten Verstärker für die Registrierung bioelektrischer Vorgänge mit Metallmikroelektroden betrieben werden können. Es ist Zweck dieser Arbeit, den Verzerrungstyp einer bioelektrischen Registrierung zu demonstrieren, welcher beim Gebrauch von Metallmikroeletroden verschiedener Flächen auftritt, wenn der Verstärkereingang eine auswählbare resistive Eingangsimpedanz hat. Es wird auch gezeigt, daß eine Beziehung zwischen Elektrodenfläche und Eingangsimpedanz für bestimmte Verzerrungsgrade besteht. In einer vorangegangenen Arbeit (Geddes und Baker, 1966) wurde gezeigt, daß eine solche Beziehung bei der Aufnahme des Elektrokardiogramms mit kleinen Elektroden besteht. In der hier mitgeteilten Untersuching wurde das Elektromyogramm vom Froschgastrocnemius als bioelektrischer Vorgang für die Untersuchung der Beziehung zwischen Eingangsimpedanz und Elektrodenfläche herangezogen.
    Notes: Abstract The high impedance of glass micropipettes is widely recognized and appropriate attention is given to the amplifier input impedance required to reproduce bioelectric events recorded with these electrodes. However, similar precautions are often ignored when using metal microelectrodes, because it is often assumed that their impedance is much lower than micropipettes of comparable size. This paper reports on studies of the relationship between metal microelectrode area and amplifier input impedance required to record faithfully the action potential of frog skeletal muscle. The distortion of the EMG, as the amplifier input impedance was intentionally lowered in discrete steps, is quantitated in terms of the resultant per cent tilt of a square wave inserted along with the action potential. In addition, the impedance vs. frequency relationship is plotted for two metal microelectrodes of 100 and 1600 μ2 in area. This relationship shows the increased impedance at lower frequencies resulting from the capacitance produced by the electrical double layer. Results show that the minimum input impedance required for proper EMG recording ranges from 88 MΩ for steel electrodes of 500 μ2 in area to 1 megohm for electrodes of 125,000 μ2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02474249
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