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  • Polymer and Materials Science  (8)
  • X-ray solution scattering  (3)
  • Erythrina senegalensis  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Phytochemistry 35 (1994), S. 1573-1577 
    ISSN: 0031-9422
    Keywords: Erythrina senegalensis ; Leguminosae ; acetylation and epoxidation reactions. ; auriculatin ; erysenegalenseins F and G ; stem bark ; warangalone
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Phytochemistry 35 (1993), S. 245-248 
    ISSN: 0031-9422
    Keywords: 6,8-diprenylgenistein. ; 8-prenyl-luteone ; Erythrina senegalensis ; Leguminosae ; erysenegalenseins D and E ; stem bark
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European biophysics journal 15 (1987), S. 133-140 
    ISSN: 1432-1017
    Keywords: X-ray solution scattering ; synchrotron radiation ; chicken erythrocyte chromatin ; rat liver chromatin ; micrococcal nuclease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Changes in the structure of chicken erythrocyte chromatin fibres at low ionic strength resulting from enzymatic digestion, thermal denaturation and binding of Netropsin and Distamycin were monitored by synchrotron X-ray solution scattering. Digestion with micrococcal nuclease confirms the previous assignment of the 0.05 nm-1 band to an interference between nucleosomes with an average distance of 23 nm. The results of thermal denaturation indicate that above 40°C there is a progressive increase of the internucleosomal distance and that above 60°C the characteristic structure of the chromatin fibre is destroyed. Binding of Netropsin and Distamycin also results in an increase of the internucleosomal distance which can be estimated to correspond to about 0.2 nm/mol.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European biophysics journal 16 (1988), S. 177-185 
    ISSN: 1432-1017
    Keywords: X-ray solution scattering ; synchrotron radiation ; sea urchin chromatin ; solubility ; condensation ; electric dichroism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Comparison between the internucleosomal distance found by X-ray solution scattering for chicken erythrocyte (23 nm) and sea urchin (30 nm) chromatin indicates that this distance is proportional to the linker length. The diameter of the condensed sea urchin chromatin fibers is about 45 nm which is significantly larger than in chicken erythrocyte chromatin (35 nm). Trivalent cations (Gd, Tb, Cr) and the polyamines spermine and spermidine were found to induce compaction at much lower concentrations than the divalent cations but Gd, Tb and Cr induce aggregation before full compaction of the fibers. The influence of hydrogen bonding is illustrated by comparison of the effects of NaCl, ammonium chloride and alkylammonium chlorides on condensation. Solubility experiments indicate that there is a nearly linear dependence of the Mg-- concentration at which precipitation occures on chromatin concentration and confirm the differences between cations observed by X-ray scattering. The chicken erythrocyte chromatin samples were further characterized by their reduced electric dichroism. The values found are consistent with the model derived from X-ray scattering and are compared with those reported in the literature.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European biophysics journal 17 (1989), S. 245-255 
    ISSN: 1432-1017
    Keywords: X-ray solution scattering ; synchrotron radiation ; electric dichroism ; chicken erythrocyte chromatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Electric dichroism and X-ray scattering measurements on solutions of uncondensed and condensed chicken erythrocyte chromatin were interpreted on the basis of model calculations. Information about the state of uncondensed fibers in the conditions of electric dichroism measurements was obtained from scattering patterns recorded as a function of pH, in the presence of spermine and at very low monovalent cation concentrations. Electric dichroism measurements on a complex of uncondensed chromatin with methylene blue were made to determine the contribution of the linker and of the nucleosomes to the total dichroism. A new approach to calculate the dichroism from realistic structural models, which also yields other structural parameters (radius of gyration, radius of gyration of the cross-section, mass per unit length) was used. Only a restricted range of structures is simultaneously compatible with all experimental results. Further, it is shown that previous interpretations of dichroism measurements on chromatin were in contradiction with X-ray scattering data and failed to take into account the distribution of orientation of the nucleosomes in the fibers. When this is done, it is found that the linker DNA in chicken erythrocyte and sea urchin chromatin must run nearly perpendicularly to the fibre axis. Taken together with the dependence of the fibre diameter on the linker length, these results provede the strongest evidence hitherto available for a model in which the linker crosses the central part of the fibre.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Time resolved x-ray solution scattering measurements were made during thermal denaturation of DNA from various sources in the temperature range of 20-90°C. Preliminary results on the influence of fragement length, ionic strength, and origin of the DNA on the time course of the scattering are described. Interpretation is based on model calculations of the scattering patterns. The resluts indicate that, for long DNA fragments at very low ionic strength, the melting process is a continuous phenomenon over the whole temperature range. It is accompanied by a progressive decrease of the radius of gyration of the cross section and of the mass per unit length. For short fragments of 146 base pair nucleosomal core DNA, stiffening of the DNA appears to precede a sharp melting transition.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The time course of the small angle scattering pattern of amorphous poly(ethylene terephthalate), (PET), was measured during isothermal crystallization using synchrotron radiation. The samples were heated to temperatures between 117 and 145°C in an oven placed in the path of the X-ray beam. The scattering curves were measured within 10 s at intervals of 1 s so as to follow the kinetics of the process continuously. It appears that the distance between the centres of mass of the crystallites decreases with increasing crystallization time as in oriented PET. The integrated small angle scattering follows approximately the same time course as the increase in the degree of crystallinity during an isothermal crystallization yielding Avrami exponents between 5 and 7. Guinier plots of the low angle region show that the scattering can be attributed to rod-like particles.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 4 (1973), S. 81-85 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Residual stresses in the surface of gas and bath nitrided steel specimens. Residual stresses in the steels Ck 45, 34 Cr 4, 34 CrAl 6, and Ck 15 were measured by X-ray diffraction. Cylindrical specimens of the heat-treated steels were nitrided in ammonia-gas and in a Tenifer®-salt- bath. The course of residual stresses of Ith order was determined by removing thin layers. With the carbon steel Ck 15 ist shown the effect of tempering on residual stresses in bath-nitrided and quenched specimens.
    Notes: Es wird über röntgenographische Spannungsmessungen an den Stählen Ck 45, 34 Cr 4, 34 Cr Al 6 und Ck 15 berichtet. Zylindrische Proben aus den Vergütungsstählen wurden im Ammoniak-Gasstrom und im Tenifer®-Salzbad nitriert und der Verlauf der Eigenspannungen I. Art durch Abtragen und mehrfaches Messen bestimmt. Am Beispiel des Kohlenstoffstahles Ck 15 wird gezeigt, wie sich eine thermische Nachbehandlung auf die Eigenspannungen badnitrierter und nach der Behandlung in Wasser abgeschreckter Proben aus diesem Werkstoff auswirkt.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 11 (1980), S. 68-72 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Internal Stresses due to Rolling with and without SlipInternal stresses have been measured in specimens of roller bearing steel 100 Cr 6 with X-ray technique. The course of the internal stresses has been determined in dependence of the number of load cycles and slip. It is shown, that the internal stresses strongly depend on the slip magnitude.
    Notes: Mit Hilfe der röntgenographischen Eigenspannungsmessung wurde die Eigenspannungsausbildung in Proben aus 100 Cr 6 in Abhängigkeit von Überrollungszahl und Schlupf ermittelt. Es zeigt sich, daß die Eigenspannungsausbildung sehr stark vom Makroschlupf bestimmt wird.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Residual Stress Measurements on Differently Decarburized, Shot Peened and Cyclic Torsional Loaded Specimens of a Spring SteelIn addition to previous fatigue tests with the spring material 55 Cr 3, X-ray residual stress measurements were carried out on differently decarburized, shot peened and cyclic torsional loaded specimens. It was shown that longer duration of decarburization leads to higher residual tensile stress in the surface zone for not peened specimens. Shot peening, however, effects almost equal residual compressive stresses in the surface zone in spite of different starting conditions, with a slight decrease for specimens with a long duration of decarburization, which corresponds to the results of the fatigue tests.By cyclic torsional loading with mean stress the residual compressive stresses due to shot peening are diminished in the axial and circumferential directions. A main stress system is now to be found with an angle of 45° to axis, whereas the residual stresses in the s̰1-(tensile direction) retain their values, those in the s̰2-(compressive) direction are decreased distinctly.
    Notes: Im Rahmen eines von der Arbeitsgemeinschaft Industrieller Forschungsvereinigungen geförderten Forschungsvorhabens wurden zahlreiche Torsionsschwellversuche an Rundproben mit 14 mm ∅ aus dem Werkstoff 55 Cr 3 durchgeführt. Zur Interpretation der Schwingfestigkeitsergebnisse wurden Härte- und Kohlenstoffverlaufskurven in der Randschicht der einzelnen Probenvarianten aufgenommen und metallographische Untersuchungen vorgenommen [1].Um die Aussagefähigkeit der Schwingfestigkeitsergebnisse zu verbessern, wurde anschließend ein reduziertes Programm zur Untersuchung der Eigenspannungszustände der wesentlichen Abkohlungsvarianten an Proben der gleichen Charge durchgeführt. Über die Ergebnisse dieser Eigenspannungsmessungen wird im folgenden ausführlich berichtet, wobei zunächst einleitend die wichtigsten Parameter und Ergebnisse des Forschungsvorhabens zusammengefaßt dargestellt werden.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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