REVIEW: Hutchinson's Splendour of the Heavens: A Popular Authoritative Astronomy by T. E. R. Phillips and W. H. Steavenson (Eds.)

Barrett, Storrs B.

doi:10.1086/142988

Cited by 2 publications

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“…Thus, the linear dichroism measurements made were of the form25 (1) i.e., the absorbance with tangential polarization minus the absorbance with radial polarization, where, t, and t, are the extinction coefficients for light polarized in the x (horizontal, tangential) and z (vertical) directions; N is Avogadro's number; w, and w, are the average energies absorbed per molecule per second in the x and z directions; and I is the intensity of the radiation in ergs cm-2 sec-1. It may be noted that linear dichroism measurements can also be made with the polarizer at 45" to the stream flow and the analyzer polarized at 90" to this direction, i.e., LD45, = Ex+45' -t~+ 4 5~f 9 0~ (2) The relation between the recorder output and the LD of the sample is…”

Section: Apparatus and Methodsmentioning

confidence: 99%

Linear dichroism and radial flow birefringence of stream‐oriented hyaluronate solutions as a function of system pH

Barrett

1978

Biopolymers

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SynopsisThe linear dichroism in the radial direction of solution flow over a velocity gradient of approximately 10-850 sec-' has been obtained for human umbilical cord hyaluronic acid at concentrations of 0.1,0.0666, and 0.0333%, and pHs 6.0,6.5,7.0,7.5,8.0, and 8.5, a t constant ionic strength 0.1. The radial flow birefringence has also been obtained for these solutions by a Kronig-Kramers transformation. The data indicate a change in linear dichroism and optical anisotropy as a function of pH, with most of the transition across the physiological range: 7.0-7.5. Previously reported axial flow birefringence and extinction angles indicating a similar pH-dependent structural change in hyaluronate solutions across the same pH range are thus confirmed with other instrumentation. The radial birefringence measurements reported here, together with the axial measurements previously reported, permit a complete description of the refractive index tensor for each of the six solutions. The interpretation of these tensors in terms of the Peterlin modification of the Rouse-Zimm Gaussian subchain theory results in a description of entropy production induced by changes in system pH.

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Section: Apparatus and Methodsmentioning

confidence: 99%

Linear dichroism and radial flow birefringence of stream‐oriented hyaluronate solutions as a function of system pH

Barrett

1978

Biopolymers

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“…3, Table I); but the sign of the axial birefringence, Ana, changes from negative at sample pHs 6.0,6.5,7.0, 7.5, and 8.0 to positive at sample pH 8.5 (see Ref. 3, Table 11), and thus the change in the refractive index depolarization ratio shown in Fig. 2 indicates a change in the relative values of the refractive indices n, and ny as An, = (n:n$)/2n (16)…”

Section: Potassium Hyaluronate Solutions 355mentioning

confidence: 98%

Changes in the refractive index ellipsoid isotropies, symmetric anisotropies, and depolarization ratios of potassium hyaluronate solutions as a function of pH

Barrett

1979

Biopolymers

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SynopsisA new method is presented for studying the tertiary and possibly the secondary structure of a biopolymer, which is applied to the pH-dependent structural transition of potassium hyaluronate solutions. The method involves a new application of Dirac dispersion theory polarization dependence measures to isotropic and anisotropic components of the refractive index ellipsoid. Changes in the dipole moment may also be observed by this method. The pH-induced changes in viscosity and optical properties of hyaluronic acid previously reported appear to be dependent on changes in secondary and tertiary structure.

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REVIEW: Hutchinson's Splendour of the Heavens: A Popular Authoritative Astronomy by T. E. R. Phillips and W. H. Steavenson (Eds.)

Cited by 2 publications

References 0 publications

Linear dichroism and radial flow birefringence of stream‐oriented hyaluronate solutions as a function of system pH

Linear dichroism and radial flow birefringence of stream‐oriented hyaluronate solutions as a function of system pH

Changes in the refractive index ellipsoid isotropies, symmetric anisotropies, and depolarization ratios of potassium hyaluronate solutions as a function of pH

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