Fortschritte in der Physiologie und Pathologie der Blutgerinnung

Wöhlisch, Edgar

doi:10.1007/bf01757871

Cited by 3 publications

(3 citation statements)

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“…The results of figure 6 indicate a trend toward higher temperatures under larger tension. The increase in shrinkage temperature under tension has been reported by Wohlisch [15], but the experimental variation is such that the differences noted in figllre 6 may be due to sampling. The r esults of measurements of thermodynamic acLiva lion constants of various ba tches of tendons in disLilled water (pH 6 to 7) arc shown in 8 and appli caL ion of eq 3 and are calculated at 60° C. This temperature wa chosen since rapid shrinkage of tendons occurs at 60° C. All measurem ents wer e made using the 14.4-g weight .…”

Section: O·6932hmentioning

confidence: 63%

“…Chatel' [14] has presented evid ence that the amount of sm:inkage is a function of the initial temperature of the bath. Critical examination of the foregoing results tends to indicate that shrinkage does not occur at a fixed temperature, although shrinkage has been regarded as analogous to a phase change occurring at a fixed temperature [15].…”

Section: Shrinkage Of Collagenmentioning

confidence: 99%

“…Substituting this value for ~F1' and rearrangmg, 25 X 10 3 log C log [01'20 3] = -2.303 RnT+ -n -' (15) The concentration of Or203 is not known, but it will be assumed proportional to the percentage of Or203' On this basis if the logarithm of the percentage chrome is plotted against the r eciprocal of the absolute temperature of shrinkage, a straight line is expected. The data presented by Bowes, et al [5] have been tested in this manner, and a straight-line results.…”

Section: Hydrothermal Stability Of Leather and Collagenmentioning

confidence: 99%

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Rate of shrinkage of tendon collagen: Heat, entropy, and free energy of activation of the shrinkage of untreated tendon; effect of acid, salt, pickle, and tannage on the activation of tendon collagen

Weir¹

1949

J. RES. NATL. BUR. STAN.

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From isothermal m easurem ents of th e rate of shrinkage of tendon collagen, it is concluded that shrinkage is a rate process in vol ving a reaction of first ord er . The effects of ten sion an d length of soaking before shrinkage a re s tudied. Average values of heat, entropy, and free energy of shrinkage of untreated tendon are ob tain ed by app lication of t he theory of absolute reaction rates to t h e data. These values are found to be 141 kcal/ mole, 349 call mole deg, a nd 24.7 kcal /mole at 60° C, resp ectively, with standard deviations of 15 kcal/mole, 43 cal/m ole deg, and 0.6 k cal/mo.le at 60° C, respectively. M easurem ents of shrinkage temperatures are disc ussed. The effects of pH , salt, tanning, and pretannage t reatments on t he Itctivation process are studied. H eat, entropy, and free energy decrease in acid and alkaline media. Salt solut ions cause a decrease in heat and entropy but an inc rease in free energy in concentrated solutions. The effect of salt and acid in combination is co mplex, but in concentrated salt solu t ions an increase in free energy is observed. All tannages investigated, with t he exception of chrome tanning, appear to r educe t he en tropy more than the heat, t h ereby in creasing t he free energy. Chrom e tann ing in creases h eat, entropy, an d free energy markedly. An interpretation of the results is given.

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Section: O·6932hmentioning

confidence: 63%

Section: Shrinkage Of Collagenmentioning

confidence: 99%

Section: Hydrothermal Stability Of Leather and Collagenmentioning

confidence: 99%

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