scholarly journals VALENCY RULE AND ALLEGED HOFMEISTER SERIES IN THE COLLOIDAL BEHAVIOR OF PROTEINS

1923 ◽  
Vol 5 (5) ◽  
pp. 665-691 ◽  
Author(s):  
Jacques Loeb ◽  
M. Kunitz
Keyword(s):  
Osmotic Pressure ◽  
Chemical Nature ◽  
Membrane Potentials ◽  
Protein Solutions ◽  
Gelatin Solution ◽  
Protein Solution ◽  
Sulfosalicylic Acid ◽  
Protein Gel ◽  
Donnan Equilibrium ◽  
Lactic Acids

1. The action of a number of acids on four properties of gelatin (membrane potentials, osmotic pressure, swelling, and viscosity) was studied. The acids used can be divided into three groups; first, monobasic acids (HCl, HBr, HI, HNO3, acetic, propionic, and lactic acids); second, strong dibasic acids (H2SO4 and sulfosalicylic acid) which dissociate as dibasic acids in the range of pH between 4.7 and 2.5; and third, weak dibasic and tribasic acids (succinic, tartaric, citric) which dissociate as monobasic acids at pH 3.0 or below and dissociate increasingly as dibasic acids, according to their strength, with pH increasing above 3.0. 2. If the influence of these acids on the four above mentioned properties of gelatin is plotted as ordinates over the pH of the gelatin solution or gelatin gel as abscissæ, it is found that all the acids have the same effect where the anion is monovalent; this is true for the seven monobasic acids at all pH and for the weak dibasic and tribasic acids at pH below 3.0. The two strong dibasic acids (the anion of which is divalent in the whole range of pH of these experiments) have a much smaller effect than the acids with monovalent anion. The weak dibasic and tribasic acids act, at pH above 3.0, like acids the anion of which is chiefly monovalent but which contain also divalent anions increasing with pH and with the strength of the acid. 3. These experiments prove that only the valency but not the other properties of the anion of an acid influences the four properties of gelatin mentioned, thus absolutely contradicting the Hofmeister anion series in this case which were due to the failure of the earlier experimenters to measure properly the pH of their protein solutions or gels and to compare the effects of acids at the same pH of the protein solution or protein gel after equilibrium was established. 4. It is shown that the validity of the valency rule and the non-validity of the Hofmeister anion series for the four properties of proteins mentioned are consequences of the fact that the influence of acids on the membrane potentials, osmotic pressure, swelling, and viscosity of gelatin is due to the Donnan equilibrium between protein solutions or gels and the surrounding aqueous solution. This equilibrium depends only on the valency but not on any other property of the anion of an acid. 5. That the valency rule is determined by the Donnan equilibrium is strikingly illustrated by the ratio of the membrane potentials for divalent and monovalent anions of acids. Loeb has shown that the Donnan equilibrium demands that this ratio should be 0.66 and the actual measurements agree with this postulate of the theory within the limits of accuracy of the measurements. 6. The valency rule can be expected to hold for only such properties of proteins as depend upon the Donnan equilibrium. Properties of proteins not depending on the Donnan equilibrium may be affected not only by the valency but also by the chemical nature of the anion of an acid.

scholarly journals THE RECIPROCAL RELATION BETWEEN THE OSMOTIC PRESSURE AND THE VISCOSITY OF GELATIN SOLUTIONS

1921 ◽  
Vol 4 (1) ◽  
pp. 97-112 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Osmotic Pressure ◽  
Solid Particles ◽  
Protein Solutions ◽  
Reciprocal Relation ◽  
Gelatin Solution ◽  
Protein Solution ◽  
Donnan Equilibrium ◽  
Protein Ions ◽  
Protein Particles

1. These experiments confirm the conclusion that protein solutions are true solutions consisting of isolated ions and molecules, and that these solutions may or may not contain in addition solid submicroscopic particles capable of occluding water. 2. The typical influence of electrolytes on the osmotic pressure of protein solutions is due to the isolated protein ions since these alone are capable of causing a Donnan equilibrium across a membrane impermeable to the protein ions but permeable to most crystalloidal ions. 3. The similar influence of electrolytes on the viscosity of protein solutions is due to the submicroscopic solid protein particles capable of occluding water since the amount of water occluded by (or the amount of swelling of) these particles is regulated by the Donnan equilibrium. 4. These ideas are supported by the fact that the more the submicroscopic solid particles contained in a protein solution or suspension are transformed into isolated ions (e.g., by keeping gelatin solution for 1 hour or more at 45°C.) the more the viscosity of the solution is diminished while the osmotic pressure is increased, and vice versa.

scholarly journals ON THE INFLUENCE OF AGGREGATES ON THE MEMBRANE POTENTIALS AND THE OSMOTIC PRESSURE OF PROTEIN SOLUTIONS

1922 ◽  
Vol 4 (6) ◽  
pp. 769-776 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Membrane Potential ◽  
Hydrostatic Pressure ◽  
Osmotic Pressure ◽  
Membrane Potentials ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Gelatin Solution ◽  
True Solution ◽  
Hydrogen Ion Concentration ◽  
Donnan Equilibrium

1. It is shown that when part of the gelatin in a solution of gelatin chloride is replaced by particles of powdered gelatin (without change of pH) the membrane potential of the solution is influenced comparatively little. 2. A measurement of the hydrogen ion concentration of the gelatin chloride solution and the outside aqueous solution with which the gelatin solution is in osmotic equilibrium, shows that the membrane potential can be calculated from this difference of hydrogen ion concentration with an accuracy of half a millivolt. This proves that the membrane potential is due to the establishment of a membrane equilibrium and that the powdered particles participate in this membrane equilibrium. 3. It is shown that a Donnan equilibrium is established between powdered particles of gelatin chloride and not too strong a solution of gelatin chloride. This is due to the fact that the powdered gelatin particles may be considered as a solid solution of gelatin with a higher concentration than that of the weak gelatin solution in which they are suspended. It follows from the theory of membrane equilibria that this difference in concentration of protein ions must give rise to potential differences between the solid particles and the weaker gelatin solution. 4. The writer had shown previously that when the gelatin in a solution of gelatin chloride is replaced by powdered gelatin (without a change in pH), the osmotic pressure of the solution is lowered the more the more dissolved gelatin is replaced by powdered gelatin. It is therefore obvious that the powdered particles of gelatin do not participate in the osmotic pressure of the solution in spite of the fact that they participate in the establishment of the Donnan equilibrium and in the membrane potentials. 5. This paradoxical phenomenon finds its explanation in the fact that as a consequence of the participation of each particle in the Donnan equilibrium, a special osmotic pressure is set up in each individual particle of powdered gelatin which leads to a swelling of that particle, and this osmotic pressure is measured by the increase in the cohesion pressure of the powdered particles required to balance the osmotic pressure inside each particle. 6. In a mixture of protein in solution and powdered protein (or protein micellæ) we have therefore two kinds of osmotic pressure, the hydrostatic pressure of the protein which is in true solution, and the cohesion pressure of the aggregates. Since only the former is noticeable in the hydrostatic pressure which serves as a measure of the osmotic pressure of a solution, it is clear why the osmotic pressure of a protein solution must be diminished when part of the protein in true solution is replaced by aggregates.

scholarly journals VALENCY RULE AND ALLEGED HOFMEISTER SERIES IN THE COLLOIDAL BEHAVIOR OF PROTEINS

1923 ◽  
Vol 5 (5) ◽  
pp. 693-709 ◽  
Author(s):  
Jacques Loeb ◽  
M. Kunitz
Keyword(s):  
Chemical Nature ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Protein Solutions ◽  
Hofmeister Series ◽  
Protein Solution ◽  
Hydrogen Ion Concentration ◽  
Protein Gel ◽  
Protein Particles ◽  
As Solubility

It is shown by the older experiments by Loeb and by the experiments reported in this paper that the effect of salts on the membrane potentials, osmotic pressure, swelling of gelatin chloride, and that type of viscosity which is due to the swelling of protein particles, depends only on the valency but not on the chemical nature of the anion of the salt, and that the cation of the salt has no effect on these properties, if the pH of the protein solution or protein gel is not altered by the salt. The so called Hofmeister series of salt effects on these four properties are purely fictitious and due to the failure of the former authors to measure the hydrogen ion concentration of their protein solutions or gels and to compare the effects of salts at the same pH of the protein solution or the protein gel. These results confirm the older experiments of Loeb and together they furnish a further proof for the correctness of the idea that the influence of electrolytes on the four properties of proteins is determined by membrane equilibria. Such properties of proteins which do not depend on membrane equilibria, such as solubility or cohesion, may be affected not only by the valency but also by the chemical nature of the ions of a salt.

scholarly journals The potential difference occurring in a Donnan Equilibrium and the theory of colloidal behaviour

1923 ◽  
Vol 102 (719) ◽  
pp. 705-710 ◽  
Keyword(s):  
Second Law Of Thermodynamics ◽  
Great Emphasis ◽  
Potential Difference ◽  
Protein Solutions ◽  
Hydrogen Ions ◽  
Protein Solution ◽  
Strong Argument ◽  
Donnan Equilibrium ◽  
Viii And Ix ◽  
The Difference

J. Loeb, in a recent and stimulating work (1), has given a convincing, if somewhat over-emphatic, study of the colloidal behaviour of proteins in solution, based largely upon the theory of the Membrane Equilibrium first suggested by Donnan (4). In one important particular, however, his argument is incorrect. Loeb observed, by certain means (2) devised by himself, the potential difference (P. D.) between a protein solution on one side of a semipermeable membrane and a solution of acid, or of acid and salt, on the other side. He found this P. D. to vary as the concentration of hydrogen ions, or of salt, was varied, in the same manner as did a number of other factors (osmotic pressure, viscosity and swelling). He found also that this P. D. could be “calculated” from the observed difference of ρ -H (or of ρ -Cl) in the two solutions, on the basis of the theory of the Donnan Equilibrium, and he concludes that the excellent agreement between calculated and observed is a strong argument in favour of his explanation of other colloidal phenomena by that theory. This conclusion is not correct: the equality found by Loeb of the observed P. D., to that calculated from the difference of ρ -H is a necessary consequence of any mechanism which does not offend the Second Law of Thermodynamics, and in itself offers no support to the theory that the Donnan Equilibrium underlies the colloidal behaviour of protein solutions. That theory may rest on other and stronger ground; since, however, Loeb appears, throughout his book (and especially in Chapters VIII and IX) and in other places (2), (3), to lay great emphasis on this agreement of the observed P. D. with that “calculated” from the observed ρ -H’s it is necessary to point out that this agreement proves no more than that the system investigated was in equilibrium, and that the observations were accurately made.

scholarly journals MEMBRANE POTENTIALS AND CATAPHORETIC POTENTIALS OF PROTEINS

1923 ◽  
Vol 5 (4) ◽  
pp. 505-519 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Aqueous Solution ◽  
Isoelectric Point ◽  
Membrane Potentials ◽  
Double Layers ◽  
Protein Solutions ◽  
Protein Gel ◽  
Low Concentrations ◽  
Alkaline Side ◽  
Common Ion ◽  
Protein Particles

1. It has been shown in preceding publications that the membrane potentials of protein solutions or gels are determined by differences in the concentration of a common ion (e.g. hydrogen ion) inside a protein solution or protein gel and an outside aqueous solution free from protein, and that the membrane potentials can be calculated with a good degree of accuracy from Donnan's equation for membrane equilibria. 2. On the basis of the theory of electrical double layers developed by Helmholtz, we are forced to assume that the cataphoretic potentials of protein particles are determined by a difference in the concentration of the two oppositely charged ions of the same electrolyte in the two strata of an electrical double layer surrounding the protein particle but situated entirely in the aqueous solution. 3. The membrane potentials of proteins agree with the cataphoretic potentials in that the sign of charge of the protein is negative on the alkaline side and positive on the acid side of the isoelectric point of the protein in both membrane potentials and cataphoretic potentials. The two types of potential of proteins disagree, especially in regard to the action of salts with trivalent and tetravalent ions on the sign of charge of the protein. While low concentrations of these salts bring about a reversal of the sign of the cataphoretic potentials of protein particles (at least in the neighborhood of the isoelectric point), the same salts can bring the membrane potentials of proteins only to zero, but call bring about no or practically no reversal of the sign of charge of the protein. Where salts seem to bring about a reversal in the membrane potential of protein solutions, the reversal is probably in reality always due to a change in the pH. 4. We may state, as a result of our experiments, that the cataphoretic migration and the cataphoretic P.D. of protein particles or of suspended particles coated with a protein are the result of two groups of forces; namely, first, forces inherent in the protein particles (these forces being linked with the membrane equilibrium between protein particles and the outside aqueous solution); and second, forces inherent entirely in the aqueous solution surrounding the protein particles. The forces inherent in the protein particles and linked with the membrane equilibrium prevail to such an extent over the forces inherent in the water, that the sense of the cataphoretic migration of protein particles is determined by the forces resulting from the membrane equilibrium.

scholarly journals Sampling of interstitial fluid and measurement of colloid osmotic pressure (COPi) in pigs: evaluation of the wick method

1998 ◽  
Vol 32 (4) ◽  
pp. 439-445 ◽  
Author(s):  
J. K. Heltne ◽  
P. Husby ◽  
M.-E. Koller ◽  
T. Lund
Keyword(s):  
Osmotic Pressure ◽  
Interstitial Fluid ◽  
Acute Inflammation ◽  
Circulatory Arrest ◽  
Colloid Osmotic Pressure ◽  
Protein Solutions ◽  
Protein Solution ◽  
Young Pigs ◽  
In Series

The wick method for sampling of interstitial fluid from subcutis was applied in fluid balance studies in young pigs. Colloid osmotic pressure was measured in serum (COPs) and interstitial fluid (COPi) using a membrane colloid osmometer. Our aims were to determine the 'true' COPi, and to find the optimal duration of wick implantation. In series I ( n=6) a 'crossover' experiment was performed using wicks soaked in different priming solutions (nondiluted and diluted serum protein solutions or isotonic salt solution). Circulatory arrest was induced just before wick insertion in order to eliminate the vascular part of the acute inflammation. In series II ( n=6) wicks were removed in sequence after 60, 90, 120 and 180 min sampling time in anaesthetized pigs in vivo. COPs, COPi and haematocrit (HCT) together with haemoglobin (Hgb), serum albumin and total protein concentrations were determined in the same animals. In series I average COPs and COPi were 13.7 (1.4) and 7.2 (1.4) mmHg respectively (SD). In series II the optimal wick implantation times were estimated to be 60–90 min for wicks soaked in diluted protein solution, and 90–120 min for dry and saline-soaked wicks. COPs averaged 13.0 (0.7) mmHg, HCT 30.0 (1.6)%, Hgb 8.3 (0.9) g/dl, s-albumin 22.7 (0.6) g/l and s-protein 47.3 (2.3) g/l. Compared to commonly reported reference values, we found surprisingly low values for most of the measured variables. This may be related to the fact that we used immature pigs. An analysis of the validity of the wick method based on our own results and published reports is presented. We conclude that sampling of interstitial fluid with subcutaneous wicks is easy to perform in young pigs. However, the COP-values measured in wick fluid have to be carefully evaluated especially when sampling is performed in vivo.

scholarly journals DONNAN EQUILIBRIUM AND THE PHYSICAL PROPERTIES OF PROTEINS

1921 ◽  
Vol 4 (1) ◽  
pp. 73-95 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
High Viscosity ◽  
Relative Volume ◽  
Solid Particles ◽  
Protein Solutions ◽  
Gelatin Solution ◽  
Hydrogen Ion Concentration ◽  
Egg Albumin ◽  
Donnan Equilibrium ◽  
Order Of Magnitude ◽  
Protein Particles

1. The proof is completed that the influence of electrolytes on the viscosity of suspensions of powdered particles of gelatin in water is similar to the influence of electrolytes on the viscosity of solutions of gelatin in water. 2. It has been suggested that the high viscosity of proteins is due to the existence of a different type of viscosity from that existing in crystalloids. It is shown that such an assumption is unnecessary and that the high viscosity of solutions of isoelectric gelatin can be accounted for quantitatively on the assumption that the relative volume of the gelatin in solution is comparatively high. 3. Since isoelectric gelatin is not ionized, the large volume cannot be due to a hydration of gelatin ions. It is suggested that this high volume of gelatin solutions is caused by the existence in the gelatin solution of submicroscopic pieces of solid gelatin occluding water, the relative quantity of which is regulated by the Donnan equilibrium. This would also explain why the influence of electrolytes on the viscosity of gelatin solutions is similar to the influence of electrolytes on the viscosity of suspensions of particles of gelatin. 4. This idea is supported by experiments on solutions and suspensions of casein chloride in which it is shown that their viscosity is chiefly due to the swelling of solid particles of casein, occluding quantities of water regulated by the Donnan equilibrium; and that the breaking up of these solid particles into smaller particles, no longer capable of swelling, diminishes the viscosity. 5. This leads to the idea that proteins form true solutions in water which in certain cases, however, contain, side by side with isolated ions and molecules, submicroscopic solid particles capable of occluding water whereby the relative volume and the viscosity of the solution is considerably increased. This accounts not only for the high order of magnitude of the viscosity of such protein solutions but also for the fact that the viscosity is influenced by electrolytes in a similar way as is the swelling of protein particles. 6. We therefore reach the conclusion that there are two sources for the viscosity of protein solutions; one due to the isolated protein ions and molecules, and the other to the submicroscopic solid particles contained in the solution. The viscosity due to the isolated molecules and ions of proteins we will call the general viscosity since it is of a similar low order of magnitude as that of crystalloids in solution; while the high viscosity due to the submicroscopic solid protein particles capable of occluding water and of swelling we will call the special viscosity of protein solutions. Under ordinary conditions of hydrogen ion concentration and temperature (and in not too high a concentration of the protein in solution) the general viscosity due to isolated ions and molecules prevails in solutions of crystalline egg albumin and in solutions of metal caseinates (where the metal is monovalent) while under the same conditions the second type of viscosity prevails in solutions of gelatin and in solutions of acid-salts of casein; and also in solutions of crystalline egg albumin at a pH below 1.0 and at higher temperatures. The special viscosity is higher in solutions of gelatin than of casein salts for the probable reason that the amount of water occluded by the submicroscopic solid gel particles in a gelatin solution is, as a rule, considerably higher than that occluded by the corresponding particles of casein.

scholarly journals HYDROPHILIC AND HYDROPHOBIC COLLOIDS AND THE INFLUENCE OF ELECTROLYTES ON MEMBRANE POTENTIALS AND CATAPHORETIC POTENTIALS

1924 ◽  
Vol 6 (3) ◽  
pp. 307-328 ◽  
Author(s):  
Jacques Loeb
Keyword(s):  
Membrane Potentials ◽  
Ion Concentration ◽  
Protein Solutions ◽  
Depressing Effect ◽  
Hydrogen Ion Concentration ◽  
Donnan Equilibrium ◽  
Low Concentrations ◽  
Protein Gels ◽  
The Difference ◽  
Charging Effect

1. In order to be able to compare the effects of electrolytes on membrane potentials and cataphoretic potentials it seems necessary to distinguish between the charging and depressing effect of electrolytes on these potentials. Only low concentrations of acids and alkalies have a charging effect on the membrane potentials of proteins, while low concentrations of neutral salts have only a depressing effect; in the case of the cataphoretic potentials, low concentrations of salts have a charging effect as have also low concentrations of alkalies and in some cases low concentrations of acids. This difference finds its explanation in the difference of the origin of the two potentials and there can therefore be no common theory for the charging effect of electrolytes in the two cases. 2. There exists, however, an analogy in the depressing action of electrolytes on the two types of potentials inasmuch when the maximal P.D. is reached, all three kinds of electrolytes, acids, alkalies, and neutral salts, have a depressing effect on both types of potentials (taking into due consideration the effect of changes in the hydrogen ion concentration). 3. This depressing effect is adequately explained for the membrane potentials of protein solutions and protein gels on the basis of the Donnan equilibrium, and the question arises whether the same explanation may also hold for the cataphoretic potentials. 4. The active ion in the depressing action of electrolytes on membrane potentials as well as on cataphoretic potentials has the opposite sign of charge from that of the colloidal particle. It had been shown before that only the valency but not the chemical nature of the active ion determines the depressing effect in the case of membrane potentials and it is shown in this paper that the same is true for the cataphoretic potentials of particles of collodion, mastic, Acheson's graphite, and denatured egg albumin. 5. It is shown that the same valency rule holds also for the effect of acids on the cataphoretic potentials of collodion particles coated with gelatin, and that the ratio of the effect of dibasic to that of mono-basic acids is approximately 0.66, as Donnan's theory of membrane potentials would demand. 6. If we have a right to conclude from the validity of the valency rule for cataphoretic potentials that the depressing effect of electrolytes on the cataphoretic P.D. is determined by the Donnan equilibrium, we can understand the analogy between the depressing action of electrolytes on membrane potentials of hydrophilic colloids and on the cataphoretic potentials of hydrophobic colloids. We can also understand the analogy between the influence of electrolytes on the precipitation of hydrophobic colloids and on the depression of the values of all those properties of hydrophilic colloids which depend on the Donnan equilibrium, since the precipitation of hydrophobic colloids occurs when the cataphoretic P.D. is depressed below a critical value.

scholarly journals The Different Colors of mAbs in Solution

Antibodies ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 21
Author(s):  
Alexandre Ambrogelly
Keyword(s):  
Visual Inspection ◽  
Quantitative Methods ◽  
Geographical Area ◽  
Therapeutic Protein ◽  
Protein Solutions ◽  
Protein Solution ◽  
Critical Quality Attribute ◽  
Recombinant Therapeutic Protein ◽  
Protein Variants ◽  
Antibody Solution

The color of a therapeutic monoclonal antibody solution is a critical quality attribute. Consistency of color is typically assessed at time of release and during stability studies against preset criteria for late stage clinical and commercial products. A therapeutic protein solution’s color may be determined by visual inspection or by more quantitative methods as per the different geographical area compendia. The nature and intensity of the color of a therapeutic protein solution is typically determined relative to calibrated standards. This review covers the analytical methodologies used for determining the color of a protein solution and presents an overview of protein variants and impurities known to contribute to colored recombinant therapeutic protein solutions.

scholarly journals On the nature and permeability of chitin II—The permeability of the uncalcified chitin lining the foregut of homarus

1936 ◽  
Vol 120 (816) ◽  
pp. 15-41 ◽  
Keyword(s):  
Thin Layer ◽  
Osmotic Pressure ◽  
Chemical Nature ◽  
Biological Significance ◽  
Decapod Crustacea ◽  
End Products ◽  
Vital Stains ◽  
Physical Tests ◽  
Pass Through ◽  
Broad Outline

It has been shown (Yonge, 1932) that the integument of the Decapod Crustacea, as exemplified by the uncalcified lining of the foregut of the lobster, Homarus vulgaris , consists of two layers which differ widely in nature and origin. There is a thin superficial cuticle which is hyaline, possesses adsorbed lipin, and is formed by the widely distributed tegumental glands the function of which had previously been obscure. The actual chemical nature of this thin layer was not determined but it is not chitin from which it can be distinguished by a variety of chemical and physical tests. The underlying and much thicker layer of the integument consists of lamellated chitin formed by the cells of the epithelium. The present research was designed to determine in broad outline the permeability of this membranous integument, and in particular the influence upon this of the bounding cuticle and the general biological significance of the cuticle. In the Crustacea, Jordan and Lam (1918) found that the foregut and hindgut of Astacus , which are lined with chitin, behave as semipeimeable membranes, allowing water, but not dissolved substances, either electrolytes or non-electrolytes, to pass through under the influence of osmotic pressure. Similar results were obtained by Yonge (1924) with the foregut of Nephrops . Very different results were obtained from similar experiments with the midgut of both Astacus and Nephrops , indicating that the peculiar properties of the remainder of the gut are due to the chitinous lining. Murlin (1902) and Nicholls (1931) have shown that the chitin which lines the so-called midgut in Oniscus, Porcellio , and other land Isopoda, and in Ligia oceanica respectively, is permeable to the end-products of digestion. Krogh (1915) states that the gills of Astacus are practically impermeable to urethane. Fischel (1908), Koehring (1930, 1931), Gickelhorn (1931), and Bond (1933) have all found some evidence for the penetration of the integument of various Cladocera and Copepoda by vital stains.

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