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  • 1965-1969  (10)
  • 1960-1964  (6)
  • 1945-1949  (2)
  • 1915-1919  (1)
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Year
  • 11
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 212 (1966), S. 477-479 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] THE fate of nuclear material and cellular structures in keratinizing cells is uncertain1. Deoxyribonucleic acid (DNA) disappears during keratinization, but it is not known whether the degradation products are retained by the keratinized cells, resorbed into the animal, or lost as epidermal detritus ...
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 199 (1963), S. 701-702 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] When the 'node' is stimulated by direct current there is a repetitive response. Before the first action potential a normal local potential develops, but the following action potentials arise at a level of depolarization greater than the amplitude of the first local potential. Therefore no pacemaker ...
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 187 (1960), S. 960-961 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1. Crimp deterioration in fine Merino and Polwarth wools in changing from normal (1) to 'doggy' (3) In changing from normal to doggy, fine and medium Merino and Polwarth wools pass through an intermediate phase with secondary waves superimposed on the normal crimp ; in strong Merino wool the ...
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 7 (1964), S. 115-119 
    ISSN: 1570-7458
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Kohlfliege, Hylemyia brassicae (Bouché), wurde vom Ei bis zur Imago auf keimfreiem Kohlrüben-Gewebe gezogen. Insgesamt verpuppten sich 17 aseptische Larven; und die 6 Männchen und 7 Weibchen, die später daraus schlüpften, waren ebenfalls bakterienfrei. Die Larven entwickelten sich nicht auf hitzesterilisiertem Gewebe, oder wenn dieses Gewebe mit fäulniserregenden Bakterien versetzt wurde. Ein Vergleich der Larvalentwicklung auf aseptischen Kohlrüben-Stücken, die mit verschiedenen Arten fäulniserregender Bakterien infiziert waren, zeigt, daß sich die Larven am besten entwickelten, wenn keine Bakterien anwesend waren oder wenn das Kohlrüben-Gewebe nur langsam faulte. Es kamen weniger Larven zur Verpuppung, und die Puparien waren am kleinsten, wenn die Larven mit Kohlrüben-Gewebe ernährt wurden, das infolge Befalls mit Erwinia atroseptica (van Hall) Jennison oder Erwinia carotovora (Jones) Holland rasch faulte. Die Verpuppungs-Prozentsätze der Larven nach Fütterung mit Kohlrüben-Stücken, die mit E. atroseptica, E. carotovora, einer unbekannten Erwinia-Art (die eine langsame Fäulnis verursacht) oder einem Gemisch von E. atroseptica und der Erwinia-Art infiziert waren, sowie in der Kontrolle (ohne Bakterien), betrugen 28, 55, 70, 81, und 75%. Eine unbekannte Erwinia-Art, die durchgängig von verschiedenen Entwicklungsstadien der Kohlfliege von Kohlrüben-Feldern isoliert werden konnte, hemmte die von E. atroseptica ausgelösten Fäulnisprozesse, wenn ein Gemisch der beiden Bakterien in Kohlrüben-Gewebestücke gebracht wurde. Dies vermag zum Teil das geringe Auftreten der Weichfäule auf Kohlrüben-Feldern zu erklären, die von Kohlfliegen befallen sind.
    Notes: Abstract The cabbage maggot, Hylemyia brassicae (Bouché) was reared from egg to adult under aseptic conditions on rutabaga (Swede; Brassica napus napobrassica). No larvae survived either on contaminated or uncontaminated rutabaga plugs sterilized by heat. A comparison of larval development on rutabaga inoculated with several species of decay-producing bacteria showed that larvae developed best on healthy uncontaminated rutabaga tissue or on rutabaga tissue that decayed slowly. Survival was lowest and puparia were smallest when larvae fed on plugs that were decayed rapidly by virulent soft-rot bacteria.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 7 (1964), S. 1-8 
    ISSN: 1570-7458
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Es wurde die Beziehung zweier Kohlfliegen-Populationen (Hylemyia brassicae Bouché) zu fäulniserregenden Bakterien an Kreuzblütlern in Verbindung mit dem von den Larven verursachten Schaden untersucht. 92 bez. 90% der Eier und 100 bez. 35% der Puparien, die sich an Kohlrüben und Chinakohl entwickelten, trugen pathogene Bakterien. Pathogene Kulturen wurden von 44% der Präpuppen-Häute aus Puparien der Chinakohl-Populationen erhalten. Die Larven vermochten fäulniserregende Bakterien wirksam auf gesunde Gewebe zu übertragen und förderten die Entwicklung und Ausbreitung der Fäule. Beim Schlüpfen waren die Imagines innerlich nicht stark kontaminiert, beschmierten sich aber offenbar äußerlich durch Kontakt mit dem Inneren der Puppengehäuse und der Präpuppen-Häute. Ein als Erwinia spec. identifizierter Bakterientyp konnte durchgängig von allen Stadien der Kohlfliege isoliert werden, die sich an Kohlrüben entwickelten. Er verursacht bei Kohlrüben eine langsame nekrotische Fäulnis und dunkle Verfärbung der befallenen Gewebe. Dieses Bakterium scheint antagonistisch zu anderen Bakterien zu sein, da nur sehr wenige andere Keime mit Stadien der Insekten dieser Population vergesellschaftet gefunden wurden. Umgekehrt fanden sich viele verschiedene Bakterientypen auf Stadien der auf dem Chinakohl lebenden Kohlfliegen. Die Virulenz der pathogenen Kulturen variierte beträchtlich, jedoch verursachten alle irgendeine Art der Weichfäule. Einige dieser aus dem Inneren oberflächlich sterilisierter Puparien isolierten Kulturen wurden als Pseudomonas spec. and Aerobacter spec. bestimmt. Die Art der bakteriellen Kontamination der Kohlfliege scheint hauptsächlich von der Empfänglichkeit ihrer kreuzblütigen Wirtspflanzen gegenüber verschiedenen Typen der Fäulnis nach Verletzung durch die Kohlfliegenmaden abhängig zu sein. Die allgemeinen Zusammenhänge zwischen dem Insekt und den fäulniserregenden Bakterien werden beschrieben.
    Notes: Abstract Bacteria pathogenic to crucifers were isolated from 92% of the eggs from flies of the cabbage maggot, Hylemyia brassicae (Bouché) of a population from rutabaga (Swede; Brassica napus napobrassica) and from 90% of those from a population from Chinese cabbage (Brassica pekinensis). The larvae transmitted the decay-causing bacteria to healthy tissues and aided in the development and spread of the rot. Of bacterial isolates from the interior of surface-sterile puparia, decay was caused by 100% of those from the rutabaga population and 35% of those from Chinese cabbage. Pathogenic cultures were also obtained from 44% of the prepupal linings of the Chinese cabbage population. The light internal contamination of adults at eclosion showed that the flies became contaminated externally from the interior of the puparia. The two populations of H. brassicae studied were contaminated with distinctly different types of bacteria. Erwinia sp., the predominant isolate from the rutabaga population, grew best on rutabaga. It caused a slow necrotic collapse and a dark pigmentation of the tissues, but not a soft-rot. Many different types of bacterial contaminants were associated with the stages of the cabbage maggot from Chinese cabbage. Green pigmenting, non-pathogenic forms were very prevalent. All pathogenic cultures caused some type of soft-rot. Some of these cultures were identified as Pseudomonas sp. and Aerobacter sp.
    Type of Medium: Electronic Resource
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  • 16
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the terminal sensilla on the maxillary palps of Schistocerca gregaria has been investigated. Most organules include six neurons with dendrites extending to the tip of the cuticular peg, the opening of which is controlled so that the dendrites are not always exposed. The neurons are isolated from each other by a neurilemma cell and two other glial cells, while typical epidermal cells containing dense bundles of microtubules support the whole group of cells. At the poles of the neurons are specialised areas in which the cytoplasm is differentiated from that elsewhere. It contains a large number of mitochondria and small helical structures, while close to it are characteristic spheres of membranes, termed onion bodies, in various stages of development. It is suggested that the fluid bathing the distal parts of the dendrites and exuding from the tip of the peg has a number of specialised functions. It is probably concerned in forcing open the tip of the peg by hydrostatic pressure, it prevents the exposed tips of the dendrites from desiccating and it acts as a transmitter in which chemicals on the surfaces touched by the sensillum must dissolve before reaching the dendrites. This fluid may be produced by the neurilemma cell or by the neurons themselves. Closure of the pegs does not seem to produce any material reduction in the overall loss of water by the insect. Each neuron sends an axon to the brain; there is no peripheral fusion of axons. Possibly one neuron has a mechanoreceptor function, although no specialised terminal at the base of the peg has been observed. The concentration of mitochondria at either end of the neuron may be concerned in the production of action potentials, while the cavity of the peg and tormogen cell perhaps has a role in the conduction of the receptor potential to the perikaryon. Intercellular connections are such as to give mechanical stability to the cells of the organule and permit transport between the cells. Extracellular tubules extending from the wall of the peg into the cell complex may serve to anchor the peg during the moulting process.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 527-537 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dilatometric measurements were made to determine the change in apparent specific volume ϕ of DNA resulting from thermal denaturation in neutral solution, ϕ increased continuously with temperature in the range 10-85°C. No deviations from a monotonically rising curve were observed in the ϕ versus temperature profile in the region of the melting temperature. The results are interpreted in terms of a partial loss of the preferentially bound DNA hydration shell. The nature of the well known buoyant density difference between native and denatured DNA was investigated by evaluating the densities in a series of cesium salt gradients at constant temperature. Extrapolation of the results to zero water activity indicates that the partial specific volumes of anhydrous native and denatured DNA are equal. The density difference at nonzero water activities is attributed to decreased hydration in the denatured state. The absence of a related change in ϕ accompanying the denaturation in the dilatometric experiments suggests that the probable volume change associated with loss of bound water during denaturation is accompanied by other compensatory volume effects. The possible nature of these volume effects is discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 18
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 19
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 4 (1966), S. 29-57 
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The γ-radiation-induced free-radical copolymerization of ethylene and CO has been investigated over a wide range of pressure, initial gas composition, radiation intensity, and temperature. At 20°C., concentrations of CO up to 1% retard the polymerization of ethylene. Above this concentration the rate reaches a maximum between 27.5 and 39.2% CO and then decreases. The copolymer composition increases only from 40 to 50% CO when the gas mixture is varied from 5 to 90% CO. A relatively constant reactivity ratio is obtained at 20°C., indicating that CO adds 23.6 times as fast as an ethylene monomer to an ethylene free-radical chain end. For a 50% CO gas mixture, the above value of 23.6 and the copolymerization rate decrease with increasing temperature to 200°C. The kinetic data indicate a temperature-dependent depropagation reaction. Infrared examination of copolymers indicates a polyketone structure containing —CH2—CH2— and —CO— units. The crystalline melting point increases rapidly from 111 to 242°C., as the CO concentration in the copolymer increases from 27 to 50%. Molecular weight of copolymer formed at 20°C. increased with increasing CO, indicating M̄n values 〉20,000. Increasing reaction temperature results in decreasing molecular weight. Onset of decomposition for a 50% CO copolymer was measured at ≈250°C.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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