Scaling relations for aqueous polyelectrolyte-salt solutions. 3. Osmotic pressure as a function of molar mass and ionic strength in the semidilute regime

1983 ◽  
Vol 16 (2) ◽  
pp. 231-236 ◽  
Author(s):  
R. S. Koene ◽  
T. Nicolai ◽  
Michel Mandel
Keyword(s):  
Ionic Strength ◽  
Osmotic Pressure ◽  
Molar Mass ◽  
Scaling Relations ◽  
Salt Solutions

Endo-D-galacturonanase immobilized by adsorption on porous polyethyleneterephthalate

1982 ◽  
Vol 47 (10) ◽  
pp. 2716-2723 ◽  
Author(s):  
Lubomíra Rexová-Benková ◽  
Jiřina Omelková ◽  
Vladimír Kubánek
Keyword(s):  
Ionic Strength ◽  
High Stability ◽  
Relative Activity ◽  
Operational Stability ◽  
The Other ◽  
Fixation Strength ◽  
Action Pattern ◽  
Salt Solutions ◽  
Buffer Solution ◽  
Degradation Degree

Endo-D-galacturonanase of Aspergillus sp. was irreversibly adsorbed on polyethyleneterephthalate in an acetate 0.1 mol l-1 buffer solution of pH 4.2. Immobilization of the enzyme resulted in lowering of its activity, the measure of which depended on the amount of the enzyme fixed on the carrier. The highest relative activity (42.4%) had the preparation containing 5.25 mg of the enzyme per 1 g of the carrier. The velocity and intensity of the sorption of the enzyme depended on the ionic strength of the medium, whilst pH, on the other hand, was of no influence. Endo-D-galacturonanase immobilized in a 0.1 mol l-1 buffer was characteristic a) of its fixation strength in salt solutions of various ionic strength and pH, in a 3 mol l-1 guanidine solution, and also in sodium pectate and pectin solutions, b) of its high stability during a long-lasting storage at 4 °C, c) of its operational stability. The immobilization led to a partial change of the action pattern onto the high-molecular substrate, manifested in lowering the decrease of viscosity to degradation degree ratio.

ON THE MECHANISM OF THE DISSOLUTION OF MAGNESIUM IN ACIDIC SALT SOLUTIONS: I. PHYSICAL CONTROL BY SURFACE FILMS

1953 ◽  
Vol 31 (9) ◽  
pp. 849-867 ◽  
Author(s):  
E. J. Casey ◽  
R. E. Bergeron
Keyword(s):  
Ionic Strength ◽  
Chemical Control ◽  
Corrosion Potential ◽  
Surface Film ◽  
Surface Films ◽  
Salt Solutions ◽  
Acidic Solutions ◽  
Activity Temperature ◽  
Acidic Salt ◽  
High Concentrations

A kinetic study and analysis has been made of the effects of ionic strength, acid activity, temperature, and salt type on the dissolution of magnesium in acidic salt solutions. This is an example of the simplest type of corrosion involving hydrogen evolution. The results are interpreted in terms of the effects of the various factors on the structure of a surface film which must be magnesium oxide and/or hydroxide even in acidic solutions. The importance of internal dissolutions in the film at high concentrations of attacking reagent, for this and other cases, is shown. Owing to complex formation, under certain conditions an odd case of "chemical control" of the dissolution rate in this simplest case becomes evident. Corrosion potential measurements aid in the interpretation.

GERMINATION OF ALFALFA VARIETIES IN SOLUTIONS OF VARYING OSMOTIC PRESSURE AND RELATIONSHIP TO WINTER HARDINESS

1959 ◽  
Vol 39 (3) ◽  
pp. 384-394 ◽  
Author(s):  
D. H. Heinrichs
Keyword(s):  
Sodium Chloride ◽  
Osmotic Pressure ◽  
Laboratory Experiments ◽  
Reliable Method ◽  
Winter Hardiness ◽  
The Other ◽  
General Tendency ◽  
Salt Solutions ◽  
Sodium Chloride Solutions ◽  
Alfalfa Varieties

Two laboratory experiments were conducted to evaluate the reliability of amount of germination in solutions of varying osmotic pressure, as a means of separating alfalfa varieties into winter-hardiness classes. In one test 23 varieties or strains were studied, and in the other 36. It was found that significant differences exist between certain alfalfa varieties in their ability to germinate in sucrose or sodium chloride solutions of 3, 6, and 9 atmospheres. There is a general tendency for non-hardy varieties to germinate more rapidly and more completely than hardy ones but there are many exceptions to this trend. Germination in solutions of 6 atmospheres osmotic pressure at 5 days gave the best separation of varieties on the basis of their ability to germinate. Germination was generally better in solutions of sucrose at 6 atmospheres osmotic pressure than in solutions of sodium chloride of the same osmotic pressure but several varieties germinated equally well in either solution. The results indicate that germinating alfalfa in sugar or salt solutions is not a reliable method for differentiating alfalfa varieties into winter hardiness classes.

On the dissociation of the sheep haemoglobin molecule at neutral pH II. Sedimentation equilibrium measurements

1971 ◽  
Vol 176 (1045) ◽  
pp. 461-480 ◽  
Keyword(s):  
Ionic Strength ◽  
Osmotic Pressure ◽  
High Speed ◽  
Dissociation Constants ◽  
Average Molecular Weight ◽  
Sedimentation Equilibrium ◽  
Neutral Ph ◽  
Haemoglobin Type ◽  
Solvent Control ◽  
Preferential Uptake

The Yphantis method of high-speed sedimentation equilibrium has been used to investigate the dissociation of sheep haemoglobin (type B) at low protein concentration (0.01 to 0.1 g/dl) in both NaCl (buffered and unbuffered) and phosphate buffer solutions at approximately neutral pH, over a range of ionic strength, temperatures of 5 and 25°C being employed. The importance of reliable ‘blank’ solvent control experiments was clearly demonstrated experimentally and weight average molecular weight data were shown to be more reliable than number averages. Apart from work at 25°C and high ionic strengths, the results are compatible with a reversible tetramer-dimer ( α 2 β 2 ⇌ 2 αβ ) dissociation. The dissociation constants obtained showed considerable agreement with those determined by osmotic pressure (reported in the previous paper) for the lower ionic strengths ( I < 1.0), but at 2 mol/l NaCl and 5°C, the sedimentation equilibrium value was 40 % higher. This probably arises through the preferential uptake of water from the high ionic strength solvent, though some dimer-monomer ( αβ ⇌ α + β ) dissociation cannot be completely excluded. On the other hand, in 2 mol/l NaCl at 25°C, the presence of monomeric units was strongly indicated, in conformity with osmotic pressure and other indications. At low NaCl concentrations, the dissociation was not significantly affected by a temperature increase from 5 to 25°C, but in phosphate solutions of comparable ionic strength, significantly less dissociation occurred and an enthalpy increase on dissociation of 55 to 63 kJ/mol was observed.

scholarly journals THE SWELLING AND OSMOTIC PRESSURE OF GELATIN IN SALT SOLUTIONS

1926 ◽  
Vol 8 (4) ◽  
pp. 317-337 ◽  
Author(s):  
John H. Northrop ◽  
M. Kunitz
Keyword(s):  
Bulk Modulus ◽  
Osmotic Pressure ◽  
Salt Solution ◽  
Modulus Of Elasticity ◽  
Elastic Limit ◽  
Ion Concentration ◽  
Salt Solutions ◽  
Original Volume ◽  
Expected Result ◽  
Do So

1. The swelling and the osmotic pressure of gelatin at pH 4.7 have been measured in the presence of a number of salts. 2. The effect of the salts on the swelling is closely paralleled by the effect on the osmotic pressure, and the bulk modulus of the gelatin particles calculated from these figures is constant up to an increase in volume of about 800 per cent. As soon as any of the salts increase the swelling beyond this point, the bulk. modulus decreases. This is interpreted as showing that the elastic limit has been exceeded. 3. Gelatin swollen in acid returns to its original volume after removal of the acid, while gelatin swollen in salt solution does not do so. This is the expected result if, as stated above, the elastic limit had been exceeded in the salt solution. 4. The modulus of elasticity of gelatin swollen in salt solutions varies in the same way as the bulk modulus calculated from the osmotic pressure and the swelling. 5. The increase in osmotic pressure caused by the salt is reversible on removal of the salt. 6. The observed osmotic pressure is much greater than the osmotic pressure calculated from the Donnan equilibrium except in the case of AlCl3, where the calculated and observed pressures agree quite closely. 7. The increase in swelling in salt solutions is due to an increase in osmotic pressure. This increase is probably due to a change in the osmotic pressure of the gelatin itself rather than to a difference in ion concentration.

THE NUMBER OF SUBUNITS IN THE MOLECULE OF HORSE HEMOGLOBIN

1956 ◽  
Vol 34 (4) ◽  
pp. 411-425 ◽  
Author(s):  
M. E. Reichmann ◽  
J. Ross Colvin
Keyword(s):  
Light Scattering ◽  
Osmotic Pressure ◽  
Performic Acid ◽  
Approach To Equilibrium ◽  
Salt Solutions ◽  
Covalent Bonds ◽  
Molecular Weights ◽  
Equilibrium Sedimentation ◽  
Hemoglobin Molecule ◽  
Ph Range

The molecular weights of horse hemoglobin, horse globin, and performic acid oxidized horse globin were determined by osmotic pressure, by an approach to equilibrium sedimentation, and by light scattering (except hemoglobin) at pH 1.5 to 2.5 in 0.05 M NaCl. Sedimentation coefficients were determined for these materials over the same pH range and electrophoretic analyses were made from pH 1.5 to 4.0. The results show that in dilute salt solutions below pH 2.5 horse hemoglobin dissociates to four subunits all approximately equal in mass but at least two of which differ electrokinetically and therefore in composition. The subunits are probably held together in the native hemoglobin molecule only by non-covalent bonds.

scholarly journals Correction to “FRET Analysis of Ionic Strength Sensors in the Hofmeister Series of Salt Solutions Using Fluorescence Lifetime Measurements”

2020 ◽  
Vol 124 (37) ◽  
pp. 8199-8199
Author(s):  
Robert C. Miller ◽  
Cody P. Aplin ◽  
Taryn M. Kay ◽  
Ryan Leighton ◽  
Christin Libal ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Fluorescence Lifetime ◽  
Hofmeister Series ◽  
Salt Solutions ◽  
Lifetime Measurements
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