Scaling relations for aqueous polyelectrolyte salt solutions. 4. Electric birefringence decay as a function of molar mass and concentration

1986 ◽  
Vol 19 (6) ◽  
pp. 1760-1768 ◽  
Author(s):  
Sybren S. Wijmenga ◽  
Frans Van der Touw ◽  
Michel Mandel
Author(s):  
William F. Tivol ◽  
Murray Vernon King ◽  
D. F. Parsons

Feasibility of isomorphous substitution in electron diffraction is supported by a calculation of the mean alteration of the electron-diffraction structure factors for hemoglobin crystals caused by substituting two mercury atoms per molecule, following Green, Ingram & Perutz, but with allowance for the proportionality of f to Z3/4 for electron diffraction. This yields a mean net change in F of 12.5%, as contrasted with 22.8% for x-ray diffraction.Use of the hydration chamber in electron diffraction opens prospects for examining many proteins that yield only very thin crystals not suitable for x-ray diffraction. Examination in the wet state avoids treatments that could cause translocation of the heavy-atom labels or distortion of the crystal. Combined with low-fluence techniques, it enables study of the protein in a state as close to native as possible.We have undertaken a study of crystals of rat hemoglobin by electron diffraction in the wet state. Rat hemoglobin offers a certain advantage for hydration-chamber work over other hemoglobins in that it can be crystallized from distilled water instead of salt solutions.


Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.


2019 ◽  
Vol 94 (2) ◽  
pp. 35-44 ◽  
Author(s):  
G. Toleutay ◽  
◽  
A.V. Shakhvorostov ◽  
S.K. Kabdrakhmanova ◽  
S.E. Kudaibergenov ◽  
...  

2010 ◽  
Vol 25 (3) ◽  
pp. 310-318 ◽  
Author(s):  
Tero Taipale ◽  
Janne Laine ◽  
Susanna Holappa ◽  
Jonni Ahlgren ◽  
Juan Cecchini

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