scholarly journals INFLUENCE OF THE CONCENTRATION OF ELECTROLYTES ON SOME PHYSICAL PROPERTIES OF COLLOIDS AND OF CRYSTALLOIDS

1920 ◽  
Vol 2 (3) ◽  
pp. 273-296 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Physical Properties ◽  
Osmotic Pressure ◽  
Initial Rate ◽  
Charged Particles ◽  
Distilled Water ◽  
Neutral Salt ◽  
Gelatin Solution ◽  
Acid Salt ◽  
Cent Solution ◽  
Depressing Effect

1. When a 1 per cent solution of a metal gelatinate, e.g. Na gelatinate, of pH = 8.4 is separated from distilled water by a collodion membrane, water will diffuse into the solution with a certain rate which can be measured by the rise of the level of the liquid in a manometer. When to such a solution alkali or neutral salt is added the initial rate with which water will diffuse into the solution is diminished and the more so the more alkali or salt is added. This depressing effect of the addition of alkali and neutral salt is greater when the cation of the electrolyte added is bivalent than when it is monovalent. This seems to indicate that the depressing effect is due to the cation of the electrolyte added. 2. When a neutral M/256 solution of a salt with monovalent cation (e.g. Na2SO4 or K4Fe(CN)6, etc.) is separated from distilled water by a collodion membrane, water will diffuse into the solution with a certain initial rate. When to such a solution alkali or neutral salt is added, the initial rate with which water will diffuse into the solution is diminished and the more so the more alkali or salt is added. The depressing effect of the addition of alkali or neutral salt is greater when the cation of the electrolyte added is bivalent than when it is monovalent. This seems to indicate that the depressing effect is due to the cation of the electrolyte added. The membranes used in these experiments were not treated with gelatin. 3. It can be shown that water diffuses through the collodion membrane in the form of positively charged particles under the conditions mentioned in (1) and (2). In the case of diffusion of water into a neutral solution of a salt with monovalent or bivalent cation the effect of the addition of electrolyte on the rate of diffusion can be explained on the basis of the influence of the ions on the electrification and the rate of diffusion of electrified particles of water. Since the influence of the addition of electrolyte seems to be the same in the case of solutions of metal gelatinate, the question arises whether this influence of the addition of electrolyte cannot also be explained in the same way, and, if this be true, the further question can be raised whether this depressing effect necessarily depends upon the colloidal character of the gelatin solution, or whether we are not dealing in both cases with the same property of matter; namely, the influence of ions on the electrification and rate of diffusion of water through a membrane. 4. It can be shown that the curve representing the influence of the concentration of electrolyte on the initial rate of diffusion of water from solvent into the solution through the membrane is similar to the curve representing the permanent osmotic pressure of the gelatin solution. The question which has been raised in (3) should then apply also to the influence of the concentration of ions upon the osmotic pressure and perhaps other physical properties of gelatin which depend in a similar way upon the concentration of electrolyte added; e.g., swelling. 5. When a 1 per cent solution of a gelatin-acid salt, e.g. gelatin chloride, of pH 3.4 is separated from distilled water by a collodion membrane, water will diffuse into the solution with a certain rate. When to such a solution acid or neutral salt is added—taking care in the latter case that the pH is not altered—the initial rate with which water will diffuse into the solution is diminished and the more so the more acid or salt is added. Water diffuses into a gelatin chloride solution through a collodion membrane in the form of negatively charged particles. 6. When we replace the gelatin-acid salt by a crystalloidal salt, which causes the water to diffuse through the collodion membrane in the form of negatively charged particles, e.g. M/512 Al2Cl6, we find that the addition of acid or of neutral salt will diminish the initial rate with which water diffuses into the M/512 solution of Al2Cl6, in a similar way as it does in the case of a solution of a gelatin-acid salt.

scholarly journals ION SERIES AND THE PHYSICAL PROPERTIES OF PROTEINS

1921 ◽  
Vol 3 (3) ◽  
pp. 391-414 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Physical Properties ◽  
Osmotic Pressure ◽  
Opposite Sign ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Depressing Effect ◽  
Protein Solution ◽  
Hydrogen Ion Concentration ◽  
Specific Effects ◽  
Protein Ions

1. Ions with the opposite sign of charge as that of a protein ion diminish the swelling, osmotic pressure, and viscosity of the protein. Ions with the same sign of charge as the protein ion (with the exception of H and OH ions) seem to have no effect on these properties as long as the concentrations of electrolytes used are not too high. 2. The relative depressing effect of different ions on the physical properties of proteins is a function only of the valency and sign of charge of the ion, ions of the same sign of charge and the same valency having practically the same depressing effect on gelatin solutions of the same pH while the depressing effect increases rapidly with an increase in the valency of the ion. 3. The Hofmeister series of ions are the result of an error due to the failure to notice the influence of the addition of a salt upon the hydrogen ion concentration of the protein solution. As a consequence of this failure, effects caused by a variation in the hydrogen ion concentration of the solution were erroneously attributed to differences in the nature of the ions of the salts used. 4. It is not safe to draw conclusions concerning specific effects of ions on the swelling, osmotic pressure, or viscosity of gelatin when the concentration of electrolytes in the solution exceeds M/16, since at that concentration the values of these properties are near the minimum characteristic of the isoelectric point.

scholarly journals AMPHOTERIC COLLOIDS

1919 ◽  
Vol 1 (5) ◽  
pp. 559-580 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Acetic Acid ◽  
Physical Properties ◽  
Osmotic Pressure ◽  
Protein Molecule ◽  
Cent Solution ◽  
The Difference ◽  
Bromide Solutions

1. When we plot the values of osmotic pressure, swelling, and viscosity of gelatin solutions as ordinates over the pH as abscissæ, practically identical curves are obtained for the effect of monobasic acids (HCl, HBr, HNO3, and acetic acid) on these properties. 2. The curves obtained for the effect of H2SO4 on gelatin are much lower than those obtained for the effect of monobasic acids, the ratio of maximal osmotic pressures of a 1 per cent solution of gelatin sulfate and gelatin bromide being about 3:8. The same ratio had been found for the ratio of maximal osmotic pressures of calcium and sodium gelatinate. 3. The curves representing the influence of other dibasic and tribasic acids, viz. oxalic, tartaric, succinic, citric, and phosphoric, upon gelatin are almost identical with those representing the effect of monobasic acids. 4. The facts mentioned under (2) and (3) permit us to decide between a purely chemical and a colloidal explanation of the influence of acids on the physical properties of gelatin. In the former case we should be able to prove, first, that twice as many molecules of HBr as of H2SO4 combine with a given mass of gelatin; and, second, that the same number of molecules of phosphoric, citric, oxalic, tartaric, and succinic acids as of HNO3 or HCl combine with the same mass of gelatin. It is shown in the present paper that this is actually the case. 5. It is shown that gelatin sulfate and gelatin bromide solutions of the same pH have practically the same conductivity. This disproves the assumption of colloid chemists that the difference in the effect of bromides and sulfates on the physical properties of gelatin is due to a different ionizing and hydratating effect of the two acids upon the protein molecule.

scholarly journals AMPHOTERIC COLLOIDS

1919 ◽  
Vol 1 (3) ◽  
pp. 363-385 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Osmotic Pressure ◽  
Isoelectric Point ◽  
Volumetric Analysis ◽  
Gelatin Solution ◽  
Cent Solution ◽  
Ph Values ◽  
Alkaline Side ◽  
Previously Treated ◽  
Bromine Number ◽  
Generally True

1. The method of removing the excess of hydrobromic acid after it has had a chance to react chemically with gelatin has permitted us to measure the amount of Br in combination with the gelatin. It is shown that the curves representing the amount of bromine bound by the gelatin are approximately parallel with the curves for the osmotic pressure, the viscosity, and swelling of the gelatin solution. This proves that the curves for osmotic pressure are an unequivocal function of the number of gelatin bromide molecules formed under the influence of the acid. The cc. of 0.01 N Br in combination with 0.25 gm, of gelatin we call the bromine number. 2. The explanation of this influence of the acid on the physical properties of gelatin is based on the fact that gelatin is an amphoteric electrolyte, which at its isoelectric point is but sparingly soluble in water, while its transformation into a salt with a univalent anion like gelatin Br makes it soluble. The curve for the bromine number thus becomes at the same time the numerical expression for the number of gelatin molecules rendered soluble, and hence the curve for osmotic pressure must of necessity be parallel to the curve for the bromine number. 3. Volumetric analysis shows that gelatin treated previously with HBr is free from Br at the isoelectric point as well as on the more alkaline side from the isoelectric point (pH ≧ 4.7) of gelatin. This is in harmony with the fact that gelatin (like any other amphoteric electrolyte) can dissociate on the alkaline side of its isoelectric point only as an anion. On the more acid side from the isoelectric point gelatin is found to be in combination with Br and the Br number rises with the pH. 4. When we titrate gelatin, treated previously with HBr but possessing a pH = 4,7, with NaOH we find that 25 cc. of a 1 per cent solution of isoelectric gelatin require about 5.25 to 5.5 cc. of 0.01 N NaOH for neutralization (with phenolphthalein as an indicator). This value which was found invariably is therefore a constant which we designate as "NaOH (isoelectric)." When we titrate 0.25 gm. of gelatin previously treated with HBr but possessing a pH < 4.7 more than 5.5 cc. of 0.01 N NaOH are required for neutralization. We will designate this value of NaOH as "(NaOH)n," where n represents the value of pH. If we designate the bromine number for the same pH as "Brn" then we can show that the following equation is generally true: (NaOH)n = NaOH (isoelectric) + Brn. In other words, titration with NaOH of gelatin (previously treated with HBr) and being on the acid side of its isoelectric point results in the neutralization of the pure gelatin (NaOH isoelectric) with NaOH and besides in the neutralization of the HBr in combination with the gelatin. This HBr is set free as soon as through the addition of the NaOH the pH of the gelatin solution becomes equal to 4.7. 5. A comparison between the pH values and the bromine numbers found shows that over 90 per cent of the bromine or HBr found was in our experiments in combination with the gelatin.

scholarly journals AMPHOTERIC COLLOIDS

1918 ◽  
Vol 1 (1) ◽  
pp. 39-60 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Physical Properties ◽  
Osmotic Pressure ◽  
Isoelectric Point ◽  
Alkali Treatment ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Neutral Salt ◽  
Sharp Drop ◽  
Hydrogen Ion Concentration ◽  
Alkaline Side

1. It has been shown in this paper that while non-ionized gelatin may exist in gelatin solutions on both sides of the isoelectric point (which lies for gelatin at a hydrogen ion concentration of CH = 2.10–5 or pH = 4.7), gelatin, when it ionizes, can only exist as an anion on the less acid side of its isoelectric point (pH > 4.7), as a cation only on the more acid side of its isoelectric point (pH < 4.7). At the isoelectric point gelatin can dissociate practically neither as anion nor as cation. 2. When gelatin has been transformed into sodium gelatinate by treating it for some time with M/32 NaOH, and when it is subsequently treated with HCl, the gelatin shows on the more acid side of the isoelectric point effects of the acid treatment only; while the effects of the alkali treatment disappear completely, showing that the negative gelatin ions formed by the previous treatment with alkali can no longer exist in a solution with a pH < 4.7. When gelatin is first treated with acid and afterwards with alkali on the alkaline side of the isoelectric point only the effects of the alkali treatment are noticeable. 3. On the acid side of the isoelectric point amphoteric electrolytes can only combine with the anions of neutral salts, on the less acid side of their isoelectric point only with cations; and at the isoelectric point neither with the anion nor cation of a neutral salt. This harmonizes with the statement made in the first paragraph, and the experimental results on the effect of neutral salts on gelatin published in the writer's previous papers. 4. The reason for this influence of the hydrogen ion concentration on the stability of the two forms of ionization possible for an amphoteric electrolyte is at present unknown. We might think of the possibility of changes in the configuration or constitution of the gelatin molecule whereby ionized gelatin can exist only as an anion on the alkaline side and as a cation on the acid side of its isoelectric point. 5. The literature of colloid chemistry contains numerous statements which if true would mean that the anions of neutral salts act on gelatin on the alkaline side of the isoelectric point, e.g. the alleged effect of the Hofmeister series of anions on the swelling and osmotic pressure of common gelatin in neutral solutions, and the statement that both ions of a neutral salt influence a protein simultaneously. The writer has shown in previous publications that these statements are contrary to fact and based on erroneous methods of work. Our present paper shows that these claims of colloid chemists are also theoretically impossible. 6. In addition to other physical properties the conductivity of gelatin previously treated with acids has been investigated and plotted, and it was found that this conductivity is a minimum in the region of the isoelectric point, thus confirming the conclusion that gelatin can apparently not exist in ionized condition at that point. The conductivity rises on either side of the isoelectric point, but not symmetrically for reasons given in the paper. It is shown that the curves for osmotic pressure, viscosity, swelling, and alcohol number run parallel to the curve of the conductivity of gelatin when the gelatin has been treated with acid, supporting the view that these physical properties are in this case mainly or exclusively a function of the degree of ionization of the gelatin or gelatin salt formed. It is pointed out, however, that certain constitutional factors, e.g. the valency of the ion in combination with the gelatin, may alter the physical properties of the gelatin (osmotic pressure, etc.) without apparently altering its conductivity. This point is still under investigation and will be further discussed in a following publication. 7. It is shown that the isoelectric point of an amphoteric electrolyte is not only a point where the physical properties of an ampholyte experience a sharp drop and become a minimum, but that it is also a turning point for the mode of chemical reactions of the ampholyte. It may turn out that this chemical influence of the isoelectric point upon life phenomena overshadows its physical influence. 8. These experiments suggest that the theory of amphoteric colloids is in its general features identical with the theory of inorganic hydroxides (e.g. aluminum hydroxide), whose behavior is adequately understood on the basis of the laws of general chemistry.

scholarly journals Kekasaran Permukaan Resin Komposit Nanofilled dan Nanohybrid Setelah Paparan Asap Rokok Kretek

2019 ◽  
Vol 8 (1) ◽  
pp. 30
Author(s):  
Johanna Chandra ◽  
Laksmiari Setyowati ◽  
Setyabudi Setyabudi
Keyword(s):  
Surface Roughness ◽  
Physical Properties ◽  
Cigarette Smoke ◽  
Public Health Problem ◽  
Composite Resins ◽  
Dental Composites ◽  
Distilled Water ◽  
Control Groups ◽  
The Past ◽  
Nanohybrid Composite

Background: Cigarette smoking is a public health problem that may influence physical properties of dental composites. Surface roughness is one of the physical properties of restorative materials that can influence their success. The use of nanofilled and nanohybrid composites in dentistry has substantially increased over the past few years. Purpose: The purpose of this study was to evaluate the surface roughness of nanofilled and nanohybrid composite resins exposed to kretek cigarette smoke. Methods: Twelve cylindrical specimens were prepared of each material and divided into two groups (n=6). For the control groups, the specimens were immersed in distilled water for 24 hours at 37oC and the water was renewed daily. For the experimental groups, the specimens were exposed daily to kretek cigarette smoke, then washed and stored in distilled water at 37oC. After 21 days, specimens were measured using a Surface Roughness Tester and the data was statistically analyzed. Result: Independent-T Test revealed that there were statistically significant differences in the surface roughness between control and experimental groups both nanofilled and nanohybrid, and between experimental groups nanofilled and nanohybrid. Conclusion: The exposure to kretek cigarette smoke can significantly increase the surface roughness of nanohybrid composites more than nanofilled composites.

The area and volume of single human erythrocytes during gradual osmotic swelling to hemolysis

1970 ◽  
Vol 48 (6) ◽  
pp. 369-376 ◽  
Author(s):  
Peter B. Canham ◽  
David R. Parkinson
Keyword(s):  
Osmotic Pressure ◽  
Single Cells ◽  
Ringer Solution ◽  
Potassium Ion ◽  
Distilled Water ◽  
Red Cell ◽  
Dialysis Membrane ◽  
Osmotic Swelling ◽  
Cell Changes ◽  
Area And Volume

A double-chambered slide was designed for the microscope which would enable continuous viewing of cells hanging on edge in a Ringer solution which was gradually being reduced in osmotic pressure. This was achieved by putting a dialysis membrane between the cell chamber and a chamber containing distilled water. Photographs were taken at 1-min intervals of single cells on edge (revealing the biconcave profile) until the cells hemolyzed, usually within 30 min. The area and volume of revolution of each cell were calculated from measurements on photographic enlargements. No significant change in area occurs during the swelling series although the red cell changes gradually from biconcave to spherical and remains spherical for approximately 7 min before hemolyzing. This stability is best explained by a leakage of potassium ion from the cell prior to hemolysis (which has been reported by Seeman to be approximately 20%).

scholarly journals Studies on antagonism.―I. The effect of the presence of salts of monovalent, divalent, and trivalent kations on the intake of calcium and ammonium ions by potato tuber tissue

1933 ◽  
Vol 112 (778) ◽  
pp. 451-472 ◽  
Keyword(s):  
Chemical Analysis ◽  
Physical Properties ◽  
Absorption Rate ◽  
Initial Rate ◽  
Final Position ◽  
Ammonium Ions ◽  
Conductivity Method ◽  
Tuber Tissue ◽  
Rate Of Absorption ◽  
The Subject

The intake of salts by storage tissues has been worked out at some length by Stiles using both the conductivity method and chemical analysis to determine the alteration in concentration of the solution supplied to the tissue. Results of these investigations as well as those of other workers on the subject point to the fact that salts are not taken in as such, but as their constituent ions, which may be absorbed to a very different degree. Stiles (1924) found that the ions were absorbed comparatively rapidly at first, for a period lasting up to 10 hours, after which there was a gradual falling off in the absorption rate so that after 24 hours absorption was only proceeding very slowly. It was also suggested that the initial rate of absorption depended more on the physical properties of the ions, such as their mobility and the coefficients of diffusion of their salts, and bore, it was found, no relationship to the final position of equilibrium (Stiles, 1919).

Characterization of Insoluble Monovalent K+, Tl+ and Ag+ Salts of 12-Tungstophosphoric Acid

2007 ◽  
Vol 555 ◽  
pp. 207-212 ◽  
Author(s):  
M.R. Todorović ◽  
I. Holclajtner-Antunović ◽  
U.B. Mioč ◽  
D. Bajuk-Bogdanović
Keyword(s):  
Thermal Analysis ◽  
Impedance Spectroscopy ◽  
Heteropoly Acid ◽  
Physicochemical Characterization ◽  
Tungstophosphoric Acid ◽  
Neutral Salt ◽  
Acid Salt

The K3PW12O40, K2.5H0.5PW12O40, K2HPW12O40, KH2PW12O40, Ag3PW12O40 and Tl3PW12O40 salts were synthesized and characterized by thermal analysis, IR and impedance spectroscopy, and SEM. The physicochemical characterization of acid alkaline salts revealed the presence of biphasic mixtures of unreacted heteropoly acid and its neutral salt. The unreacted heteroply acid could be washed away by treating the acid salt with water.

scholarly journals THE INFLUENCE OF ALCOHOL UPON THE GROWTH OF SEEDLINGS

1926 ◽  
Vol 8 (3) ◽  
pp. 215-231 ◽  
Author(s):  
Raymond Pearl ◽  
Agnes Allen
Keyword(s):  
Osmotic Pressure ◽  
Ethyl Alcohol ◽  
Cucumis Melo ◽  
Distilled Water ◽  
Selective Action ◽  
Total Growth ◽  
Growth Of Seedlings

In this paper it is shown that if the dry seeds of the cantaloupe (Cucumis melo) are soaked for 3 hours in solutions of ethyl alcohol of concentration ranging from 2 to 16 per cent by volume, and then germinated and grown in distilled water in the dark, the total growth attained is greater by amounts ranging from 9 to 35 per cent than is that made by seeds treated in every way identically except that they are initially soaked in distilled water instead of alcohol. It is shown that this result is not due simply to differences in osmotic pressure in the different alcohol solutions. It is probably due to a simple selective action of the alcohol which eliminates the constitutionally weak and defective seeds.

scholarly journals Use of a Glucose Bismuth Sulphite Iron Medium for the Isolation of B. typhosus and B. proteus

1927 ◽  
Vol 26 (4) ◽  
pp. 374-391 ◽  
Author(s):  
W. James Wilson ◽  
E. M. Mcv. Blair
Keyword(s):  
Sodium Phosphate ◽  
Inhibitory Action ◽  
Brilliant Green ◽  
Ferrous Sulphate ◽  
Sodium Sulphite ◽  
Distilled Water ◽  
Cent Solution ◽  
Bismuth Citrate ◽  
The Media ◽  
Made In

1. The development and use of a medium which has selective properties for the growth of B. typhosus and B. proteus is described.2. The principle of the method rests (1) on the positive property of the B. typhosus of being able to reduce a sulphite to a sulphide in the presence of glucose, (2) on the inhibitory action on the growth of B. coli of a bismuth sulphite in the presence of a certain excess of sodium sulphite.3. The media finally developed are made in the following way:A. To 100 c.c. of a melted 3 per cent. nutrient agar are added 5 c.c. of a 20 per cent. solution of glucose, 10 c.c. of a 20 per cent. solution of sodium sulphite (anhydrous), 5 c.c. of a standard bismuth solution. After boiling for two minutes an addition is made of 1 grm. of exsiccated sodium phosphate and 1 c.c. of an 8 per cent. solution of ferrous sulphate crystals.Medium B is the same as above with the addition of 0·5 c.c. of a 1 per cent. watery solution of brilliant green. The standard liquor bismuthi is prepared by mixing 60 grm. bismuth citrate with 50 c.c. of distilled water and then with 20 c.c. liq. ammonii sp. gr. 0·880 and finally making the volume up to 500 c.c. with distilled water.4. On these media the B. typhosus grows readily and forms flat blackdry surface colonies. B. proteus grows on the medium in a non-spreading fashion but does not form black colonies. B. coli either fails to grow or after a period of inhibition forms brown sticky raised colonies.5. Bismuth media were used in the examination of 31 enteric stools and in 30 instances the infecting microorganism was successfully isolated. Single examinations only were made and the material was usually 24 to 48 hours old at the time of examination.6. Emulsions of enteric stools which as shown by the usual media contained only a dozen or so of typhoid bacilli were found by our bismuth media actually to contain several thousand.7. The isolation from a case of typhoid fever of a proteus X 19 strain is recored.8. As regards its growth on bismuth sulphite media B. paratyphosus B behaves more like a reducing B. coli than a B. typhosus culture. For the isolation of B. paratyphosus B a lactose bile salt brilliant green medium is described.

Sign in / Sign up

Export Citation Format

Share Document