Hoff Law Research Articles

The osmotic pressure of liquid 3He- 4He mixtures at temperatures below the Lambda-point

The osmotic pressure of liquid 3He- 4He mixtures, condensed in a vessel connected by means of a narrow slit to a similar vessel containing pure 4He, has been measured by determining the fountain pressure exerted by the pure 4He, when heated, necessary to obtain equilibrium with the osmotic pressure of the mixture. The osmotic pressure meets Van 't Hoff's law within a few percent up to 4% concentration. A revised vapour pressure — liquid concentration relation is given, based on the results, obtained at 1.2°K.

The osmotic behavior and permeability to non-electrolytes of mitochondria

The volume changes of rat liver mitochondria exposed to hypotonic solutions or to solutions of penetrating non-electrolytes were studied by direct estimation of mitochondrial volume from photomicrographs and by changes in optical density of mitochondrial suspensions. The data permit the following conclusions about the osmotic behavior and permeability of these particles. 1. 1. Mitochondria undergo reversible volume changes in anisotonic solutions. 2. 2. Minor secondary changes of undetermined origin also occur. 3. 3. Mitochondria obey osmotic (Boyle-van't Hoff) law. 4. 4. They contain a substantial amount (40–50%) of material which does not participate in volume changes. 5. 5. There appears to be little leakage of osmotically active solute from mitochondria during short exposure to hypotonic solutions. 6. 6. A simple, empirical relation between the optical density of a mitochondrial suspension and mitochondrial volume has been established. 7. 7. Non-electrolytes permeate the mitochondria and thereby induce reversible osmotic volume changes. 8. 8. The rate of penetration is correlated with the olive oil/water partition coefficient of the compound. 9. 9. The permeability constants of the substances studied are quantitatively similar to those found for typical cells. 10. 10. Mitochondria possess a semipermeable membrane which probably contains a high proportion of lipide.

Filtration, diffusion, and molecular sieving through porous cellulose membranes.

1. A study has been made of the diffusion and filtration of a graded series of molecules (including tritium-labelled water, urea, glucose, antipyrine, sucrose, raffinose, and hemoglobin) in aqueous solution through porous cellulose membranes of three degrees of porosity. 2. Experimental results were in close agreement with predictions based on the membrane pore theory of Pappenheimer et al. (1,2). Restriction to molecular diffusion is a function of pore radius and molecular radius described by equation (11) in the text. Molecular sieving during ultrafiltration is a function of total pore area per unit path length, pore radius, molecular radius, and filtration rate given by equations (16) and (19). 3. Estimates of average pore radius made by means of this theory were considerably larger than estimates made by the method of Elford and Ferry (3) (Table II). Sources of error in the latter method are discussed and a new method of membrane calibration is proposed in which the total cross-sectional area of the pores is measured by direct diffusion of isotope-labelled water. 4. Steady-state osmotic pressures of solutions of sucrose and raffinose measured during molecular sieving through cellulose membranes were found to be close to the "ideal" osmotic pressures calculated by van't Hoff's law. Thus the present experimental data support the methods used by Pappenheimer et al. in their studies on living capillary walls as well as their theory of membrane pore permeability.

Anomalies in Osmotic Pressure Measurements

IN the course of a study of the molecular weights of coal-tar pitch fractions, we have observed unusual anomalies with two samples in benzene solution. A large number of fractions have been examined in benzene and in other solvents using modified Zimm–Meyerson osmometers fitted with specially prepared polyvinyl alcohol membranes1 of the lowest possible permeability. We and other workers2 have found samples of average molecular weight as low as 250 to be retained by the membranes, and nearly all our samples have followed van't Hoff's law almost exactly. As the full results of the investigation are being published elsewhere, attention is now directed only to the behaviour of two fractions produced by molecular distillation of that part of a coke-oven tar pitch which is insoluble in petroleum ether of boiling range 100–120° C. but soluble in benzene.

藥物作用の温度係數に關する研究

The time needed to produce a regular action by the various drugs (digitalis, strophanthine, strychnine, picrotoxin, guanidine, chloral hydrate and urethane) was measured at intervals of 5°C at the temperature of 10°C to 30°C or 35°C. In this case the dosage of each drug was changed at each temperture over a wide range, and thus temperature coefficient at each range of temperature was calculated. The results are as follows : (1) Between 15°C and 30°C temperature coefficient was not remarkably different in any drugs, increased in proportion to increase of dosage of drugs and its value was about 2. (2) In the experimental examples at 30°C to 35°C the value ot temperature coefficient (Q10) was fairly large in picrotoxin and strophanthine and on the contrary Q10 was small in urethane. At the low temperature of 10°C to 15°C Q15 became abruptly large but became reversely small in urethane. So the changing point seemed to be in the range of the above temperature. This changing point in strophanthine was about 13°C. (3) In the experiment which the surrounding temperature was artificially changed Q10 coincided with the above results. Therefore increase or decrease of the time needed to produce the action by the seasonal change seems chiefly to be due simply to the difference of the surrounding temperature. (4) The little difference of temperature coefficient among each drug should prove that the chemical change of drugs themselves or the direct participation of drugs to cellular metabolism must not be the essential quality of action of drugs. The reason which Van't Hoff's law can be applied to action of drugs may be thought that the rate of adsorption of drugs into the active point of cells is under the influence of temperature. (5) Temperature coefficient of action of drugs injected subcutaneously takes the genuine value near by the minimum effective dosage. When the time needed to the gradual increase of concentration in blood in proportion to the increase of dosage of drugs is permitted, temperature coefficient takes the larger value than the genuine one, and the process which drugs are absorbed into the blood vessel through the part injected subcutaneously does not give an influence to temperature coefficient, because in this case there may be not adsorption. (6) When the relation between the minimum effective dosage of each drug and temperature at 15°C aud 25°C was investigated, it was found that the minimum effective dosage hardly changed by the difference of temperature but had possibility to become slightly small at high temperature. (7) After all temperature coefficient of action of drugs is not nearly estimated from the active dosage, but is determined by the comparison of the time needed to produce the action of a certain dosage of drugs.

Do Chromosomes Manifest Osmotic Volume Change?

SummaryA. The applicability of the Boyle-van't Hoff law to the swelling of spermatozoa of the sea urchin, Arbacia punctulata, in hypotonic solutions of effective concentrations varying from 42.4 to 88.5% sea water was investigated. Cell volumes were determined by centrifuging in small capillaries in an air turbine at 20,000 x gravity.B. In the range of dilutions employed, the Boyle-van't Hoff law appeared to be followed. The “osmotically inactive fraction” (“b”) averaged 33%. Thus the sperm head, which is chiefly chromosomal material, has a non-swellable volume which does not differ greatly from that of certain other cells. The results indicate that the chromosomes take part in the osmotic swelling of the cell.

The Interaction between Rubber and Liquids. V. the Osmotic Pressures of Polymer Solutions in Mixed Solvents

Abstract An expression is obtained for the free energy of dilution of a ternary mixture of polymers + two liquids by one of the liquids. This is used to consider the osmotic equilibrium between a solution of a polymer in a mixture of two liquids, and a second phase containing only the two liquids. It is shown that the osmotic behavior of the ternary solution is very similar to that of a polymer in a single liquid, and in particular that van't Hoff's law holds at infinite dilution. The distribution of the two liquids between solvent and solution is also calculated. The experimental difficulties involved in the use of mixed solvents are discussed.

The interaction between rubber and liquids. V. The osmotic pressures of polymer solutions in mixed solvents

Abstract An expression is obtained for the free energy of dilution of a ternary mixture of polymers + two liquids by one of the liquids. This is used to consider the osmotic equilibrium between a solution of a polymer in a mixture of two liquids, and a second phase containing only the two liquids. It is shown that the osmotic behavior of the ternary solution is very similar to that of a polymer in a single liquid, and in particular that van't Hoff's law holds at infinite dilution. The distribution of the two liquids between solvent and solution is also calculated. The experimental difficulties involved in the use of mixed solvents are discussed.

OSMOTIC PRESSURE STUDY OF PROTEIN FRACTIONS IN NORMAL AND IN NEPHROTIC SUBJECTS

In serum of patients with nephrosis both albumin and globulin showed by osmotic pressure nearly double the molecular weights of normal albumin and globulin. In the urines of such patients, on the other hand, both proteins showed molecular weights lower even than in normal serum. The colloidal osmotic pressures were measured by the author's method at such dilutions that the van't Hoff law relating pressures to molecular concentrations could be directly applied. For the albumin and globulin of normal serum the molecular weights found were 72,000 and 164,000 respectively, in agreement with the weights obtained by other methods.

On the Biology ofCalanus finmarchicus. Part VI. Oxygen Consumption in Relation to Environmental Conditions

SUMMARY1. Experiments have been done to determine the oxygen utilisation by male, female and Stage V Calanus under different environmental conditions.2. An initial fall in the respiration of adult Calanus was observed during the first few hours after capture. Stage V do not show this clearly. It is found more often in winter than in summer.3. The lethal temperature varies from 24° C. in winter to 26° C. in summer. Stage V Calanus are more resistant to high temperatures than adults.4. Respiration rises with increase of temperature from 0° C. to 20° C. The increase does not follow van't Hoff's law. The oxygen consumption of males and females is about the same, while that of Stage V is lower. Above 20° C. there is a harmful effect.5. Within the limits studied (pH 7.4–pH 8.5) change in hydrogen-ion concentration has no effect on respiration.6. Calanus are unaffected by an increase in the oxygen content of the water, but are sensitive to low oxygen tensions. Below a concentration of about 3 ml. per litre the respiration decreases. At concentrations between 1 and 2 ml. per litre they are killed. They are more resistant at 5° C. than at 15° C. and Stage V are more resistant than adults at both these temperatures.7. Calanus can become acclimatised to salinities as low as 35–40% seawater (S=12‰–13.6‰), but their respiration is lowered at a salinity of 50%.8. Light has a striking effect on Calanus. It may increase the respiration by 100% or more. This effect can be detected also in the sea, but not below 5 metres. Continuous exposure to light is harmful.9. The bearing of these results on the distribution of Calanus is discussed.10. From the amount of oxygen used in respiration, calculations of the food required are made and these are compared with the results given by Putter for Calanus and other copepods.

The Theory of Moderate Deviations from van't Hoff's Law

A sketch of the application of van der Waals notions to the study of deviations from van't Hoff's law made by A. A. Noyes is given and a modification of the theory is introduced. An osmotic pressure equation is then deduced from a heat of formation equation. The new theory is shown to be, at least formally, in harmony with the old. Both theories result in an equation of the van der Waals type for osmotic pressures. This constitutes an extension of van't Hoff's very useful analogy between dilute solutes and gases.

Physiological Studies an Tissue in vitro. III

With the coverglass culture method, a relation between the temperature and the growth of the fibroblast in vitro was investigated. The growth was measured by tracing the surface increase.1) The growth of the tissue, which had been kept at 39° for one day after the preparation, was not a rectilinear function of the temperature between 25° and 43°, the maximum of the growth being at 39° and the minimum at 25°The growth between 25° and 39° could be approximately expressed with 2 exponential lines corresponding much more to VAN'T HOFF-ARRHENiUS's formula than to VAN'T HOFF's, with the point of inter-section lying at 30°.2) With culture tissue, which had been kept at 39° for 5 hours after the preparation the temperature influence an the growth was found to be not seriously different from the result in the former Gase. The temperature coeflicient Q10, was generally much larger than that of VAN'T HOFF's law, especially extraordinarily large between 25° and 27°. So also was the value of μ of VAN'T HOFF-ARRHENIUS.3) The growth of the tissue under alternating temperatures, but essentially under the saure temperature, that is, the growth of the tissue, which, after having been incubated at 39° for 5 hours after the preparation, was kept at a higher temperature an the first day and at a lower temperature an the second day, or vice versa, showed no essential differente between 30° and 39°. But there was a distinct differente in the Gase of 25° and 30°. The tissue which was kept first at 25° and then at 30° showed a smaller growth in comparision with that which was kept first at 30° and then at 25°.

Comparative Effect of Temperature on Rate of Pure Chemical Reactions and Rate of Sugar Utilization by a Plant and a Cold Blooded Animal

1. Raising and lowering the temperature produced an increase and decrease in sugar utilization by the plant Spirogyra, and by a cold blooded animal, the ordinary gold fish, just as it does in pure chemical reactions. 2. Lowering the temperature produced a greater decrease in sugar utilization by Spirogyra than by the gold fish. 3. The effect of temperature on the rate of sugar utilization by Spirogyra and the gold fish followed very closely van't Hoff's law for pure chemical reactions, except at very low temperatures. The explanation that suggests itself for this deviation from the law is that the normal physiological mechanism for sugar utilization in the living cells of the plant and animal is impaired by very low temperatures.

HYDRATION OF GELATIN IN SOLUTION

1. It was shown that the high viscosity of gelatin solutions as well as the character of the osmotic pressure-concentration curves indicates that gelatin is hydrated even at temperatures as high as 50 degrees C. 2. The degree of hydration of gelatin was determined by means of viscosity measurements through the application of the formula See PDF for Equation. 3. When the concentration of gelatin was corrected for the volume of water of hydration as obtained from the viscosity measurements, the relation between the osmotic pressure of various concentrations of gelatin and the corrected concentrations became linear, thus making it possible to determine the apparent molecular weight of gelatin through the application of van't Hoff's law. The molecular weight of gelatin at 35 degrees C. proved to be 61,500. 4. A study was made of the mechanism of hydration of gelatin and it was shown that the experimental data agree with the theory that the hydration of gelatin is a pure osmotic pressure phenomenon brought about by the presence in gelatin of a number of insoluble micellae containing a definite amount of a soluble ingredient of gelatin. As long as there is a difference in the osmotic pressure between the inside of the micellae and the outside gelatin solution the micellae swell until an equilibrium is established at which the osmotic pressure inside of the micellae is balanced by the total osmotic pressure of the gelatin solution and by the elasticity pressure of the micellae. 5. On addition of HCl to isoelectric gelatin the total activity of ions inside of the micellae is greater than in the outside solution due to a greater concentration of protein in the micellae. This brings about a further swelling of the micellae until a Donnan equilibrium is established in the ion distribution accompanied by an equilibrium in the osmotic pressure. Through the application of the theory developed here it was possible actually to calculate the osmotic pressure difference between the inside of the micellae and the outside solution which was brought about by the difference in the ion distribution. 6. According to the same theory the effect of pH on viscosity of gelatin should diminish with increase in concentration of gelatin, since the difference in the concentration of the protein inside and outside of the micellae also decreases. This was confirmed experimentally. At concentrations above 8 gm. per 100 gm. of H(2)O there is very little difference in the viscosity of gelatin of various pH as compared with that of isoelectric gelatin.

THE BICARBONATE RESERVE AND THE DISSOCIATION CURVE OF OXYHEMOGLOBIN IN FEBRILE CONDITIONS

THE BICARBONATE RESERVE AND THE DISSOCIATION CURVE OF OXYHEMOGLOBIN IN FEBRILE CONDITIONS

INFLUENCE OF THE CONCENTRATION OF ELECTROLYTES ON THE ELECTRIFICATION AND THE RATE OF DIFFUSION OF WATER THROUGH COLLODION MEMBRANES

1. When a watery solution is separated from pure water by a collodion membrane, the initial rate of diffusion of water into the solution is influenced in an entirely different way by solutions of electrolytes and of non-electrolytes. Solutions of non-electrolytes, e.g. sugars, influence the initial rate of diffusion of water through the membrane approximately in direct proportion to their concentration, and this. influence begins to show itself under the conditions of our experiments when the concentration of the sugar solution is above M/64 or M/32. We call this effect of the concentration of the solute on the initial rate of diffusion of water into the solution the gas pressure effect. 2. Solutions of electrolytes show the gas pressure effect upon the initial rate of diffusion also, but it commences at a somewhat higher concentration than M/64; namely, at M/16 or more (according to the nature of the electrolyte). 3. Solutions of electrolytes of a lower concentration than M/16 or M/8 have a specific influence on the initial rate of diffusion of water through a collodion membrane from pure solvent into solution which is not found in the case of the solutions of non-electrolytes and which is due to the fact that the particles of water diffuse in this case through the membrane in an electrified condition, the sign of the charge depending upon the nature of the electrolyte in solution, according to two rules given in a preceding paper. 4. In these lower concentrations the curves representing the influence of the concentration of the electrolyte on the initial rate of diffusion of water into the solution rise at first steeply with an increase in the concentration, until a maximum is reached at a concentration of M/256 or above. A further increase in concentration causes a drop-in the curve and this drop increases with a further increase of concentration until that concentration of the solute is reached in which the gas pressure effect begins to prevail; i.e., above M/16. Within a range of concentrations between M/256 and M/16 or more (according to the nature of the electrolyte) we notice the reverse of what we should expect on the basis of van't Hoff's law; namely, that the attraction of a solution of an electrolyte for water diminishes with an increase in concentration. 5. We wish to make no definite assumption concerning the origin of the electrification of water and concerning the mechanism whereby ions influence the rate of diffusion of water particles through collodion membranes from pure solvent to solution. It will facilitate, however, the presentation of our results if it be permitted to present them in terms of attraction and repulsion of the charged particles of water by the ions. With this reservation we may say that in the lowest concentrations attraction of the electrified water particles by the ions with the opposite charge prevails over the repulsion of the electrified water particles by the ions with the same sign of charge as that of the water; while beyond a certain critical concentration the repelling action of the ion with the same sign of charge as that of the water particles upon the latter increases more rapidly with increasing concentration of the solute than the attractive action of the ion with the opposite charge. 6. It is shown that negative osmosis, i.e. the diminution of the volume of the solution of acids and of alkalies when separated by collodion membranes from pure water, occurs in the same range of concentrations in which the drop in the curves of neutral salts occurs, and that it is due to the same cause; namely, the repulsion of the electrified particles of water by the ion with the same sign of charge as that of the water. This conclusion is supported by the fact that negative osmosis becomes pronounced when the ion with the same sign of charge as that of the electrified particles of water carries more than one charge.

Permeability of Certain Plant Membranes to Water

1. Quantitative measurements were made of the permeability to water of certain non-living semipermeable plant membranes under experimentally controlled conditions. 2. The apparatus and method employed had the following advantages over osmometers ordinarily employed: (1) the passage of as small a quantity of water as 0.000337 gm. could be detected; (2) the exact area of the membrane used could be calculated; (3) the concentration of the solution exerting the osmotic pressure could be kept constant. 3. The effect of temperature upon the permeability to water of the seed coat of Arachis hypogaea was measured and the temperature coefficients for 10⚬ rise in temperature were obtained. An average coefficient was not calculated. Since the temperature coefficients are not constant, but vary with the temperature, an average coefficient is without significance. 4. The temperature coefficient is lower than that according to the van't Hoff law, and is higher than the diffusion coefficient. There is no evidence that either chemical or physical processes are exclusively involved in the passage of water through the membrane. 5. The temperature coefficients showed higher values at lower temperatures and lower values at higher temperatures, and this is in agreement with the behavior of temperature coefficients in other processes. 6. A comparison is made with the temperature coefficients obtained in the permeability experiments of (1) Krabbe with living membranes, (2) Rysselberghe with living membranes, (3) Brown and Worley with non-living seed coat membranes, (4) Pfeffer with copper ferrocyanide membrane. 7. No hysteresis or after effect of a previous temperature was observed. 8. It was found that the seed coats of peanut and almond showed a difference in permeability to water in opposite directions through the membrane, the faster rate being from the external toward the internal portion of the seed. 9. When distilled water was placed on one side of the membrane, the rate of water movement was proportional to the osmotic pressure applied upon the other side, when sodium chloride solutions were used; but this proportionality did not exist when cane sugar solutions were used. 10. When solutions of varying concentrations were placed on opposite sides of the membrane, it was found that the relation between rate and concentration difference was complex, and that in general equal osmotic differences do not necessarily produce equal rates; the rate is greatly affected by changes in the concentration of the internal solution; no mathematical relation was noted between the concentration on opposite sides and the rate of water movement through the membrane. The bearing of these facts upon plasmolytic experiments based on rate of water movement through membranes was pointed out. 11. A comparison of the permeability of several plant membranes under similar conditions was made, large differences appearing.

The Osmotic Pressure of the Ions and of the Undissociated Molecules of Salts in Aqueous Solution

The concentration of the ions (Ci) and that of the undissociated molecules (CU) are involved in the equation, Ci^2 / Cu = K, expressing the application of the law of mass-action to solutions of electrolytes. Hence the large divergence from this law which strong electrolytes exhibit may be due to the behavior of the ions, to that of the undissociated molecules, or to that of both. This so called anomalous behavior may be simply expressed by saying that for one or for both of these molecular species van't Hoff's law, II = CRT, where II is the osmotic pressure, C is the concentration in mols per unit-volume, R is the gas-constant, and T is the absolute temperature, does not hold; for, if all of the molecular species entering into an equilibrium obey this law, the law of mass-action is a thermodynamic necessity. [1] In this paper is outlined and applied a method for determining the extent to which the ions and the undissociated molecules deviate from van't Hoff's law, that is, for determining the relation between the osmotic pressure of the ions or of the undissociated molecules and their concentration. The significance of the results, particularly as applied to the calculation of the degree of ionization and to the validity of the law of mass-action, is discussed.

Multiplication of Bacteria and the Influence of Temperature and some other conditions thereon

The species of organisms used were B. coli, B. typhosus and B. enteritidis Gaertner. With these organisms:(1) When a fresh broth culture is made with a small inoculation there is a period during which there is no increase in the number of bacteria present.(2) When this period is over the bacteria commence to divide regularly; this is shown by the fact that the logarithms of the numbers plotted against time are found to fall on a straight line. This regular growth persists until (or nearly until) a maximum has been reached, after which the numbers remain more or less constant and then slowly decline.The time necessary for a complete division to take place (generation time) was determined for various temperatures between 20°C. and 42°C.(3) The effect of temperatures between 20° and 35.3°C. upon the rate of multiplication is in accordance with the Arrhenius-Van 't Hoff law; above this temperature the effect diminishes.

Osmotic Theories, with Special Reference to Van't Hoff's Law

Osmotic Theories, with Special Reference to Van't Hoff's Law