scholarly journals Size heterogeneity of human cervical mucus glycoproteins. Studies performed with rate-zonal centrifugation and laser light-scattering

1987 ◽  
Vol 245 (3) ◽  
pp. 757-762 ◽  
Author(s):  
J K Sheehan ◽  
I Carlstedt
Keyword(s):  
Light Scattering ◽  
Laser Light ◽  
Laser Light Scattering ◽  
Correlation Spectroscopy ◽  
Radius Of Gyration ◽  
Intensity Measurements ◽  
The Individual ◽  
Size Heterogeneity ◽  
Mucus Glycoproteins ◽  
Good Agreement

Mucus glycoproteins (mucins) from cervical pregnancy mucus were fractionated by using rate-zonal centrifugation in a gradient of guanidinium chloride. The distribution of the macromolecules, as assessed by using sialic acid determination, suggested the presence of three populations of different size. Individual fractions were subjected to laser light-scattering performed as total-intensity measurements as well as photon correlation spectroscopy. The results showed that points of inflexion were present in the distribution of both Mr and DT (translational diffusion coefficient) and that the three populations have Mr values of approx. 24 × 10(6), 16 × 10(6) and 6 × 10(6) respectively. The weight-average Mr for the whole distribution, as calculated from the values obtained for the individual fractions, was 13.6 × 10(6), which is in good agreement with that found for the unfractionated material (11.1 × 10(6]. Plots of log RG (radius of gyration) and log (1/DT) versus log Mr are in keeping with the macromolecules being linear flexible chains.

scholarly journals Hydrodynamic properties of human cervical-mucus glycoproteins in 6m-guanidinium chloride

1984 ◽  
Vol 217 (1) ◽  
pp. 93-101 ◽  
Author(s):  
J K Sheehan ◽  
I Carlstedt
Keyword(s):  
Sedimentation Coefficient ◽  
Large Degree ◽  
Correlation Spectroscopy ◽  
Radius Of Gyration ◽  
Random Coils ◽  
Intensity Measurements ◽  
Hydrodynamic Behaviour ◽  
Stokes Radius ◽  
The Individual ◽  
The Relationship

Cervical mucins and fragments thereof were studied by sedimentation-velocity, rotatory viscometry and laser light-scattering performed as photon-correlation spectroscopy as well as low-angle total-intensity measurements. The Mr of the whole mucins is 10 × 10(6)-15 × 10(6), whereas fragments obtained after reduction of disulphide bonds (‘subunits’) have Mr 2.1 × 10(6)-2.9 × 10(6), depending on the method used. Subsequent trypsin digestion of subunits afforded glycopeptides with Mr approx. 0.4 × 10(6). The high frictional ratio for the whole mucins is interpreted as a large degree of expansion. The Stokes radius calculated from the diffusion coefficient is approx. 110nm for the whole mucins, which is in agreement with that estimated from the radius of gyration (130nm) by using the concept of the equivalent hydrodynamic sphere. The ratio of the concentration-dependence parameter for the reciprocal sedimentation coefficient (Ks) to the intrinsic viscosity ([eta]) for the whole mucins is 1.42, suggesting that the individual macromolecule occupies a spheroidal domain in solution. The relationship between [eta] and Mr for whole mucins, subunits and T-domains suggests that they are linear flexible macromolecules behaving as somewhat ‘stiff’ random coils. This conclusion is supported by the relationships between the sedimentation coefficients, the diffusion coefficients and the Mr. The hydrodynamic behaviour of the mucins is thus close to that expected for coiling macromolecules entrapping a lot of solvent, which is consistent with the postulated polymeric structure.

A New Method of Mapping and Counting Micropipes in SiC Wafers

2006 ◽  
Vol 527-529 ◽  
pp. 447-450
Author(s):  
Jian Wei Wan ◽  
Seung Ho Park ◽  
Gil Yong Chung ◽  
E.P. Carlson ◽  
Mark J. Loboda
Keyword(s):  
Light Scattering ◽  
High Resolution ◽  
Digital Imaging ◽  
Laser Light ◽  
Laser Light Scattering ◽  
New Method ◽  
Non Destructive ◽  
Koh Etching ◽  
Good Agreement

Micropipes are considered to be a major device killer in SiC wafers. Developing a method to count and map micropipes efficiently and accurately has been a challenging task to date. In this work, a new method based on KOH etching and full wafer, high resolution digital imaging is developed to map and count micropipes in both conductive and semi-insulating SiC wafers. This method is also compared with a non-destructive method based on laser light scattering and a good agreement between the two methods is demonstrated.

Solubility Behaviour of Cellulose Acetate Butyrate in Mixture of Solvents

2017 ◽  
Vol 68 (6) ◽  
pp. 1281-1284
Author(s):  
Anca Giorgiana Grigoras ◽  
Niculae Olaru
Keyword(s):  
Light Scattering ◽  
Laser Light ◽  
Second Virial Coefficient ◽  
Solvent Mixture ◽  
Laser Light Scattering ◽  
Necessary Condition ◽  
Radius Of Gyration ◽  
Scattering Method ◽  
Cellulose Derivatives ◽  
Multiangle Laser Light Scattering

In order to identify the proper solvent mixture for future processing from solution of cellulose derivatives, the laser light scattering method was used. The multiangle laser light scattering parameters of macromolecular chains in solution (weight-average molecular weigh , radius of gyration Rg and second virial coefficient A2) were correlated with the values of dielectric constant of solvent mixture (2-methoxyethanol + N,N-dimethylformamide). The experimental results revealed that the protic solvent favored the extended conformation of the macromolecules in solution, necessary condition to obtaine nanofibers by electrospinning.

scholarly journals The effect of guanidinium chloride on the behaviour of human cervical-mucus glycoproteins. Evidence for unfolding regions of ordered structure in 6M-guanidinium chloride

1984 ◽  
Vol 221 (2) ◽  
pp. 499-504 ◽  
Author(s):  
J K Sheehan ◽  
I Carlstedt
Keyword(s):  
Frictional Coefficient ◽  
Correlation Spectroscopy ◽  
Cervical Mucus ◽  
Random Coil ◽  
Radius Of Gyration ◽  
Ordered Structure ◽  
Guanidinium Chloride ◽  
Photon Correlation ◽  
The Individual ◽  
Mucus Glycoproteins

The macromolecular properties of cervical-mucus glycoproteins (mucins) were studied as a function of the concentration of guanidinium chloride with conventional light-scattering, photon-correlation spectroscopy and sedimentation-velocity centrifugation. No evidence for an association of the mucins in 0.2M-NaCl as compared with 6M-guanidinium chloride was found at mucin concentrations below approx. 0.5 mg/ml. However, an increase in the frictional coefficient and in the radius of gyration occurred with increasing concentrations of guanidinium chloride, in particular between 4 M and 6 M, suggesting an expansion of the individual macromolecule. The change in the particle-scattering function is consistent with a transition from a ‘stiff’ random coil in 0.2 M-NaCl into a more flexible one in 6 M-guanidinium chloride. We suggest that the mucins contain regions of ‘ordered’ structure which can undergo a reversible ‘unfolding’ analogous to the behaviour of a conventional globular protein exposed to a denaturing solvent. Such regions might carry sites for specific interactions between mucins and/or be decisive for their conformation and macromolecular properties in physiological solvents.

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