Untersuchungen an lyophilen Kolloiden, I

Kroepelin, H.

doi:10.1007/bf01460068

Cited by 75 publications

(6 citation statements)

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“…The concentration gradient of the diffusing nucleic acid was recorded photographically generally over a 96-hr period using the schlieren and fringe systems. Diffusion coefficients at several s-RNA calculations were computed by the maximum-ordinate, area method (Neurath, 1942), by the method of second moments (Lamm, 1937), and by the fringe method (Schachman, 1957). The viscosity of the medium was determined experimentally.…”

Section: Methodsmentioning

confidence: 99%

“…The homogeneity of the material is evidenced by the fact that essentially identical values (within 5 7 3 were ob- Viscosity. In view of the observation of Luborsky and Cantoni (1962) that the viscosity of rabbit liver +RNA is shear-rate dependent, initial viscosity measurements on wheat germ s R N A were carried out in a Cannon-Ubbelohde multibulb-type viscometer (charge 5 ml., capillary diameter 0.036 cm, and capillary length 3.07 cm), which exhibited shear gradients of 330, 180, 100, and 50 sec-I, as calculated from the equation of Kroepelin (1929). Some difficulty was experienced with these measurements in that time-dependent aggregation phenomena appeared to be occurring regularly in the viscometer, no doubt brought on by repeated passage of the nucleic acid through the capillary (triplicate runs were carried out on each sample).…”

Section: Sedimentation Velocitymentioning

confidence: 99%

See 1 more Smart Citation

Hydrodynamic and Optical Rotatory Dispersion Studies on Wheat Germ Soluble Ribonucleic Acid^*

Kay¹,

Oikawa²

1966

Biochemistry

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Section: Methodsmentioning

confidence: 99%

Section: Sedimentation Velocitymentioning

confidence: 99%

Hydrodynamic and Optical Rotatory Dispersion Studies on Wheat Germ Soluble Ribonucleic Acid^*

Kay¹,

Oikawa²

1966

Biochemistry

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“…and a capillary length of 10-2 cm. The average rate of shear, ,, calculated from the formula ,= 8v/31rrrt (Kroepelin, 1929), where v is the volume of the bulb and t the flow time, varied from 410 to 430sec.-l. The kinetic energy correction pv/8nrlt at the highest rate of shear employed was less than 0.03% and was neglected.…”

mentioning

confidence: 99%

Carp Myogens of White and Red Muscles. Properties and Amino Acid Composition of the Main Low-Molecular-Weight Components of White Muscle

Kônosu¹,

Hamoir²,

Péchère³

1965

Biochemical Journal

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1. The three main components of the 1.5-2s ultracentrifugal peak of carp myogen (white muscle) have been isolated by ammonium sulphate fractionation and zone electrophoresis, and crystallized. 2. The molecular weights of these three proteins were determined by sedimentation and diffusion, by the Archibald method and by amino acid analysis, and found to lie between 9000 and 13000. 3. Their complete amino acid compositions were determined by column chromatography and by their ultraviolet spectra. Both methods revealed abnormal compositions, including the absence of tryptophan and methionine and the presence of large amounts of phenylalanine. At most 1 residue each of tyrosine, cysteine, proline, arginine and histidine was found/molecule. 4. The specific viscosity of component 3 was lower than that of other small globular proteins described so far, a fact that suggests that these proteins approximate more closely to the ideal case of the spherical protein molecule. Also, the presence of a single residue of several amino acids, the absence of disulphide bonds, and the apparent reversibility of denaturation by urea of component 3 suggest that the study of these molecules could provide new information on the structure of proteins.

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“…interval the apparent viscosity, 7, is calculated according to Poiseuille's formula; the mean head is computed according to Meissner.14 The mean velocity gradient, G, for each interval was closely approximated with the use of Kroepelin's formula. 15 When it was desired in this present work to express the viscosity as a function of shearing stress, the latter was calculated at the wall, according to the equation:…”

Section: Long-chain Nithocellulose Moleculesmentioning

confidence: 99%

Viscosity, sedimentation, diffusion, and osmotic behavior of long‐chain nitrocellulose molecules

Newman

Loeb

1953

J. Polym. Sci.

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Viscosity, sedimentation, diffusion, and osmotic pressure measurements in ethyl acetate are reported on four unfractionated nitrocellulose polymers containing about 13.5% nitrogen and varying in molecular weight from 0.93 to 15 x 105. Detailed viscosity determinations in buret viscometers in the concentration range 0.025 to 0.300 g./dl. and over a range of velocity gradients from about 500 to 5000 sec.‐1 are presented. Viscosity data adjusted to fixed shear rates fitted closely the relation ηsp/C = [η] + a2C + a3C2. Plots of ηsp/C vs. C at different shear rates were found to diverge rapidly with increasing concentration. For the nitrate of highest molecular weight, the viscosity was strongly shear‐dependent and the intrinsic viscosity appeared to vary from 52 at 3000 sec.‐1 to 80 or more at 0 sec.‐1. The other samples displayed these tendencies less markedly with decreasing molecular weight. Other extrapolation procedures are also discussed. The intrinsic viscosity data accumulated at 500 sec.‐1 could be represented by the relation [η] = KMα; α = 0.99; the molecular weights were those obtained from sedimentation‐diffusion measurements on the unfractionated nitrocelluloses. Assuming for practical purposes α = 1, then Km (\documentclass{article}\pagestyle{empty}\begin{document}$\[= \overline {{\rm DP}} /[{\rm \eta ]}\]) is found to have the value 80 ± 3. Assuming a negligible depolymerization during nitration, the analogous factors required for cupriethylenediamine and for cuprammonium were found to be 170 and 230, respectively. The effect of varying shear rate on these factors is illustrated. The sedimentation constants obtained were readily extrapolated to infinite dilution with an expanded sedimentation‐concentration relation, S = S0/(1 + K2C + K′s C2). Diffusion constants were obtained following the second moment method and mathematically extrapolated to zero concentration according to Gralén. Molecular weights were computed with the Svedberg equation. Number average molecular weights were obtained osmotically. Some consideration of the data in terms of the theories of Debye‐Bueche and Kirkwood‐Riseman is given. It is found that both K‐R's and D‐B's theories predict the variation of intrinsic viscosity with molecular weight within twice the standard deviation of the observed slope from the frictional coefficient‐molecular weight data. In both viscosity and sedimentation the polymer appears, therefore, to behave in an approximately equally “free draining” fashion. For the calculated intrinsic viscosity of a sample of intermediate molecular weight a reasonable value is obtained from the latter theory only; but it is not uniformly successful in predicting all [η]'s, particularly those corresponding to low molecular weights. The relation between Ks, the first interaction coefficient in sedimentation and molecular dimensions, is briefly discussed. Also considered are the interaction coefficients in viscosity, especially as regards their dependence upon velocity gradient.

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Untersuchungen an lyophilen Kolloiden, I

Cited by 75 publications

References 0 publications

Hydrodynamic and Optical Rotatory Dispersion Studies on Wheat Germ Soluble Ribonucleic Acid^*

Hydrodynamic and Optical Rotatory Dispersion Studies on Wheat Germ Soluble Ribonucleic Acid^*

Carp Myogens of White and Red Muscles. Properties and Amino Acid Composition of the Main Low-Molecular-Weight Components of White Muscle

Viscosity, sedimentation, diffusion, and osmotic behavior of long‐chain nitrocellulose molecules

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Untersuchungen an lyophilen Kolloiden, I

Cited by 75 publications

References 0 publications

Hydrodynamic and Optical Rotatory Dispersion Studies on Wheat Germ Soluble Ribonucleic Acid*

Hydrodynamic and Optical Rotatory Dispersion Studies on Wheat Germ Soluble Ribonucleic Acid*

Carp Myogens of White and Red Muscles. Properties and Amino Acid Composition of the Main Low-Molecular-Weight Components of White Muscle

Viscosity, sedimentation, diffusion, and osmotic behavior of long‐chain nitrocellulose molecules

Contact Info

Product

Resources

About

Hydrodynamic and Optical Rotatory Dispersion Studies on Wheat Germ Soluble Ribonucleic Acid^*

Hydrodynamic and Optical Rotatory Dispersion Studies on Wheat Germ Soluble Ribonucleic Acid^*