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  • 1
    Electronic Resource
    Electronic Resource
    Deformation of a tethered polymer in uniform flow (2000)
    Springer
    The European physical journal 2 (2000), S. 3-30 
    Details
    ISSN: 1292-895X
    Keywords: PACS. 83.10.Nn Polymer dynamics – 83.20.Di Microscopic (molecular) theories – 83.20.Jp Computer simulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: Static properties of a single polymer fixed at one end and subjected to a uniform flow field are investigated for several polymer models: the Gaussian chain, the freely jointed chain, and the FENE (Finitely Extensible Nonlinear Elastic) chain. By taking into account first the excluded-volume interaction and subsequently also the hydrodynamic interaction, the polymer models are gradually completed and the relevance of each effect for the polymer deformation can be identified. Results from computer simulations of these bead spring chains are compared with analytical calculations using either the conformational distribution function or blob models. To this end, in contrast to the blob model with non-draining blobs introduced for a tethered polymer by Brochard-Wyart, we here develop also a model with free-draining blobs. It turns out that a limited extensibility of the polymer – described by nonlinear spring forces in the model – leads to a flow velocity dependence of the end-to-end distance, segment density, etc. which agrees with the power law predictions of the blob model only for very long chains and in a narrow range of flow velocities. This result is important for comparison with recent experiments on DNA molecules which turn out to be still rather short in this respect. The relative importance of finite extensibility, the excluded-volume effect, and hydrodynamic interactions for polymers in flow is not fully understood at present. The simulation of reasonably long chains becomes possible even when fluctuating hydrodynamic interactions are taken into account without employing averaging procedures by introducing efficient numerical approximation schemes. At medium velocity of the uniform flow the polymer is partially uncoiled and simulations show that the effects of excluded-volume and hydrodynamic interactions are position-dependent. Both are stronger near the free end than near the tethered end of the polymer. A crossover from a nearly non-draining polymer at small flow velocities to a free-draining almost uncoiled chain at large velocities is found in the simulations. Accordingly, models assuming the polymer to be composed of either free- or non-draining subunits, like the two blob models, cannot correctly describe the extension and shape of a tethered polymer in flow, and simple power laws for the polymer extension, etc. cannot be expected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s101890050036
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  • 2
    Electronic Resource
    Electronic Resource
    Rechnung und Versuch bei der scheibenförmigen Wirbelstrombremse (1921)
    Springer
    Electrical engineering 10 (1921), S. 133-156 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Zusammenfassung Es werden die verschiedenen in der Literatur vorhandenen Formeln für die Bremskraft scheibenförmiger Wirbelstrombremsen mit Messungen verglichen, und daraus Gesichtspunkte für die Konstruktion von Elektrizitäts-Zähler-Bremsen sowie experimentelle Unterlagen für die allgemeine rechnerische Behandlung des Problems (Festlegung des Maximums der Bremskraft) gewonnen. Weiter wird experimentell die Rückwirkung der Wirbelströmung auf den primären Fluß und die Verzerrung der Feldkurve durch die Rotation der Scheibe untersucht.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01578439
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  • 3
    Electronic Resource
    Electronic Resource
    Über Durchschlagsfestigkeitsmessungen an Isolierölen (1925)
    Springer
    Electrical engineering 15 (1925), S. 271-295 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01670740
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  • 4
    Electronic Resource
    Electronic Resource
    Die Stabilität eines Gleichlaufantriebs mit drehfelderregten Stromrichtermotoren (1988)
    Springer
    Electrical engineering 71 (1988), S. 281-287 
    Details
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents In this paper a multi-motor-drive with synchronous machines with AC-excitation fed by one single converter is presented. The steady state behaviour and the stability problems of this very simple drive are discussed. Based on an analytical stability analysis measures to stabilize the drive are suggested.
    Notes: Übersicht In der vorliegenden Arbeit wird ein Mehrmaschinen-Gleichlaufantrieb mit drehfelderregten Stromrichtermotoren vorgestellt, die aus einem gemeinsamen Stromrichter gespeist werden. Das stationäre Verhalten dieses Antriebs, der sich durch einen besonders einfachen Aufbau auszeichnet, und die auftretenden Stabilitätsprobleme werden beschrieben. Es wird eine analytische Stabilitätsuntersuchung durchgeführt und es werden einfache, den Wirkungsgrad des Antriebs nur geringfügig verschlechternde Stabilisierungsmaßnahmen angegeben.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01580178
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  • 5
    Electronic Resource
    Electronic Resource
    The influence exerted by sideromycins on poly-U-directed incorporation of phenylalanine in the S-30 fraction of Staphylococcus aureus (1969)
    Springer
    Archives of microbiology 68 (1969), S. 99-106 
    Details
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary In a cell-free system obtained from Staphylococcus aureus SG 511, the sideromycin antibiotics danomycin and A 22,765 inhibit the poly U-directed incorporation of phenylalanine; albomycin has no influence on this incorporation, whereas ferrimycin A1 actually enhances it. In the case of the antibiotic A 22,765 it has been demonstrated that S-30 extracts from A 22,765-sensitive cells of S. aureus behave in the same way as those from A 22,765-resistant cells; in no instance, however, was ferrioxamine B able to counteract the inhibitory effect of A 22,765. The sideromycins, which are regarded as a homogeneous group on the basis of their chemical and biological characteristics, possibly have differing mechanisms of action. The possibility that sideromycin permeation may be susceptible to antagonism by sideramines is discussed.
    Notes: Zusammenfassung In einem zellfreien System von Staphylococcus aureus SG 511 hemmen die Sideromycin-Antibiotica Danomycin und A 22 765 den Poly U-gesteuerten Einbau von Phenylalanin, dieser wird durch Albomycin nicht beeinflußt, durch Ferrimycin A1 sogar gesteigert. Für das Antibioticum A 22 765 wurde gezeigt, daß sich S-30 Extrakte A 22 765-sensibler und A 22 765-resistenter Zellen von S. aureus gleich verhalten; in keinem Falle konnte jedoch die durch A 22 765 bewirkte Hemmung durch Ferrioxamin B aufgehoben werden. Die auf Grund chemischer wie biologischer Merkmale als einheitliche Gruppe charakterisierten Sideromycine besitzen möglicherweise unterschiedliche Wirkungsmechanismen. Die Möglichkeit einer Antagonisierung der Sideromycin-Permeation durch die Sideramine wird diskutiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00413869
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  • 6
    Electronic Resource
    Electronic Resource
    Permeability of Staphylococcus aureus to the sideromycin antibiotic A 22,765 (1969)
    Springer
    Archives of microbiology 68 (1969), S. 107-112 
    Details
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary The sideromycin antibiotic A 22,765 is taken up from the medium by Staphylococcus aureus SG 511 against a concentration gradient. In contrast to this, A 22,765-resistant cells display an extremely low degree of permeability to the molecule. Ferrioxamine B penetrates the cells in only very minute quantities, but nevertheless antagonises permeation by A 22,765. This permeation-antagonising effect of ferrioxamine B is discussed.
    Notes: Zusammenfassung Das Sideromycin-Antibioticum A 22,765 wird durch Staphylococcus aureus SG 511 gegen ein Konzentrationsgefälle aus dem Medium aufgenommen. Im Gegensatz dazu zeigen A 22,765-resistente Zellen gegenüber diesem Molekül eine äußerst geringe Permeabilität. Ferrioxamin B dringt nur in sehr geringen Mengen in die Zellen ein, antagonisiert jedoch die Permeation von A 22,765. Die Hemmung dieser Permeation durch Ferrioxamin B wird diskutiert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00413870
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  • 7
    Electronic Resource
    Electronic Resource
    Reduction in the number of coupling parameters (1985)
    Springer
    Communications in mathematical physics 97 (1985), S. 211-225 
    Details
    ISSN: 1432-0916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract A method is developed for reducing the formulation of massless models with several independent couplings to a description in terms of a single coupling parameter. The original as well as the reduced system are supposed to be renormalizable and invariant under the renormalization group. For most models there are, if any, only a finite number of reductions possible including those which correspond to symmetries of the system. The reduction method leads to a consistent formulation of the reduced model in any order of perturbation theory even in cases where it is difficult to establish a symmetry in higher orders. An example where no symmetry seems to be involved is the interaction of a spinor field with a pseudoscalar field. For this model the reduction method determines the quartic coupling constant uniquely as a function of the Yukawa coupling constant. The Wess-Zumino model is an exceptional case for which the reduction method admits an infinite number of solutions besides the supersymmetric one.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01206187
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  • 8
    Electronic Resource
    Electronic Resource
    Crystallization and preliminary crystallographic analysis of two β-mannanase isoforms from Thermomonospora fusca KW3 (1996)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 52 (1996), S. 1224-1225 
    Details
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Three β-mannanase isoforms were isolated from the supernatant of a thermophilic actinomycete culture from Thermomonospora fusca KW3. Two of the isoforms (Q1, Q 1.1) were crystallized by the hanging-drop method at room temperature using ammonium sulfate as a precipitant. The isoforms form rod-shaped colorless crystals. Both belong to the orthorhombic space group P212121. The cell dimensions are a = 46.7, b = 61.1, and c = 128.2 Å for isoform Q1, and a = 43.8, b = 46.2, and c = 132.8 Å for isoform Q1.1. The asymmetric unit of either isoform contains one mannanase molecule. Native data have been collected to 2.2 Å resolution for Q1 and to 1.65 Å resolution for Q1.1 using synchrotron radiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0907444996009006
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  • 9
    Electronic Resource
    Electronic Resource
    Evaluation of Microwave Cooking Procedures and Ovens for Devitalizing Trichinae in Pork Roasts (1983)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 48 (1983), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pork roasts from pigs experimentally infected with Trichinella spiralis were cooked in five microwave ovens. Twenty-nine procedures, generally recommended by the oven manufacturers or pork interest groups, were used. Infective trichinae were present after cooking in 50 of 189 roasts. Factors affecting infectivity included procedure used, use or nonuse of post-cooking standing or temperature holding, weight of roast, and internal temperatures attained. Five visually well done roasts contained infective trichinae including one in which all five temperatures taken exceeded 76.7°C. One other infective roast, with a small red spot, also had all temperatures at or above the 76.7°C level. Recommendations are made to minimize the potential that trichinae may survive in microwaved-cooked pork.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1983.tb14916.x
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  • 10
    Electronic Resource
    Electronic Resource
    An Approach to Safe Microwave Cooking of Pork Roasts Containing Trichinella spiralis (1983)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 48 (1983), S. 0 
    Details
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pork roasts, obtained from pigs experimentally infected with Trichinella spiralis, were cooked at 50% power in four microwave ovens. The attainment of consistently well done roasts is the primary requisite for development of safe cooking methods. Recommendations for cooking of trichinous pork roasts, with adequate margins of safety, are made for each oven.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2621.1983.tb05067.x
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