bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR
Authors: Sollner Karl , Carr Charles W. 
Published: May 2004

1. Experiments were carried out to decide whether a homogeneous phase (solubility) theory or a micellar-structural theory more adequately describes the behavior of dried collodion membranes with solutions of strong electrolytes.
2. A number of dried collodion membranes were prepared from an electrochemically inactive collodion preparation (state I); the characteristic concentration potentials across them were low, about 30 mv. The membranes were activated by oxidation (state II) to give maximum or nearly maximum concentration potentials (about 50 mv.). The oxidized membranes are dried, dissolved in alcohol-ether, and a new set of dry collodion membranes prepared from this solution (state III). The concentration potentials across these membranes are low.
3. Since the properties of a homogeneous phase should not be influenced by a rearrangement of its constituent particles, the experimental results do not support a homogeneous phase (solubility) theory, but they agree with the predictions of the micellar-structural theory. The characteristic behavior of dried collodion membranes in solutions of strong inorganic electrolytes is therefore due to the micellar character of its interstices.
THE ANTIPROTEOLYTIC ACTIVITY OF SERUM
Authors: Grob David 
Published: May 2004

1. Serum antitrypsin and pancreatic trypsin inhibitor inhibited the coagulation of plasma in vitro.
2. This could be largely prevented by trypsin.
3. The anticoagulant action of the trypsin inhibitor was apparently due to its antiprothrombic action. It had no appreciable antithrombic action.
4. Examination of the blood of two hemophiliacs indicated that the prolonged coagulation time of their blood is not due to an excess of trypsin inhibitor.
5. Examination of the blood of heparinized dogs indicated that heparin does not appreciably contribute to the antiproteolytic activity of the serum.
THE MECHANISM OF THE INHIBITION OF HEMOLYSIS
Authors: Ponder Eric 
Published: May 2004

The principal conclusion of this investigation is that the inhibitory effect of plasma or serum on hemolysis by saponin and lysins of the same type is similar in nature to the inhibitory effects of certain sugars and electrolytes, which again are similar to the acceleratory effects produced by indol, benzene, and other substances already studied. All these effects, both inhibitory and acceleratory, are the result of reactions between the inhibitors or accelerators and those components of the red cell membrane which are broken down by lysins.
The inhibitory effect of plasma on saponin hemolysis has a number of properties in common with the inhibition produced by sugars and electrolytes and with accelerations in general. (a) The temperature coefficient is small and negative. (b) The extent of the inhibition depends on the type of red cell used in the hemolytic system. (c) The most satisfactory measure of the extent of the inhibition, the constant R, is a function of the concentration of lysin in the system, and (d) R is a linear function of the quantity of inhibitor present.
It is also shown that the inhibitory effect of plasma, and serum is not entirely dependent on its protein content.
The process underlying the phenomenon of lysis and its acceleration or inhibition seems to be one in which the lysin reacts with a component or components of the cell membrane in such a way as to break down its semipermeability to hemoglobin, and in which the accelerator or inhibitor also reacts with the same component in such a way as to increase or decrease the effectiveness of the lysin in producing breakdown. The membrane is considered as being an ultrastructure made up of small areas or spots of varying degrees of resistance to breakdown, the resistances being distributed according to a negatively skew type of frequency curve, and the process of lysis seems to begin with the least resistant spots breaking down first. These spots may be arranged in some regular spatial pattern, and the membrane has also to be regarded as possessing spots of varying rigidity of form. The accelerator or inhibitor changes the resistance of every reactive spot in the ultrastructure by a factor R, which suggests that acceleration and inhibition are results of some over-all effect, such as that of changing the extent to which lysin is concentrated at the surface or partitioned between the material of the membrane and the surrounding fluid. Some kind of combination between the accelerator or inhibitor and the material of the ultrastructure is presumably involved; at first the combination seems to be a loose one and partly reversible, but later some of the loose links are replaced by more permanent combinations involving the same types of bond as are broken down by the lysins themselves.
NATURE OF THE ACTION CURRENT IN NITELLA
Authors: Osterhout W. J. V. 
Published: May 2004

When a stimulus arrives before recovery is complete there may be no response or only a partial response. A typical response appears to involve an immediate loss of potential at the inner protoplasmic surface but not at the outer surface. As long as recovery is incomplete only a part of the total potential is located at the inner protoplasmic surface and the loss of this part of the total potential can cause only a partial response; i.e., one of smaller magnitude than the normal.
Even after the action curve has returned to the base line recovery may be incomplete and the response only a partial one. The return of the action curve to the base line means a recovery of total potential but if part of this is located at the outer protoplasmic surface and if this part is not lost when stimulation occurs the response can be only a partial one. During recovery there is a shift of potential from the outer to the inner protoplasmic surface. Not until this shift is completed can recovery be called complete. The response to stimulation then becomes normal because the loss of potential reaches the normal amount.
In many cases the partial responses appear to conform to the all-or-none law. In other cases this is doubtful.
THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR
Authors: Carr Charles W. , Sollner Karl 
Published: May 2004

1. The assumption, has generally been made that collodion membranes are rigid and non-swelling in water and aqueous solutions of strong electrolytes, and considerable uncertainty exists as to the manner in which water is taken up by "dried" collodion membranes. In approaching these problems experimentally, the weight and volume changes of collodion membranes when placed in water and when transferred from water to solutions of strong electrolytes were determined.
2. Dried collodion membranes swell reversibly to an appreciable extent when placed in water, the swelling varying from 5 to 11 per cent depending on the brand of collodion. The water uptake and swelling of oxidized collodion is the same as the original unoxidized preparation.
3. The water uptake as determined by the weight increase is larger than could be accounted for by the volume increase, swelling accounting for only 60 to 70 per cent of the water taken up by the membranes.
4. When the "water-wetted dried" collodion membranes were transferred from water to solutions of various strong electrolytes, there was no detectable change in volume. Similarly, when the "porous" membranes were transferred from water to solutions of strong electrolytes, there was no significant volume change.
5. When dried collodion membranes swell in water, some of the water becomes "bound" water, and both intramicellar and intermicellar swelling seem to occur. Therefore, neither the weight increase nor the volume increase nor their difference can be taken as a measure of the true pore space of the membrane. It is concluded that the important problem is not the absolute water content, but how much water in the water-wet membranes is available in useful pathways for the different solutes.
I. THE RELATION BETWEEN ATTACHMENT TO THE SUBSTRATUM AND INGESTION BY AMEBA IN STRYCHNINE SULFATE SOLUTION AND CONDITIONED MEDIA
Authors: Fennell Richard A. 
Published: May 2004

1. Strychnine sulfate 0.000069 M decreased percentage attachment to the substratum by Amoeba proteus in 0.0029 M NaCl from 77.3 to 1.3, in 0.0029 M KCl from 40.8 to 2.5, in 0.002 M CaCl2 from 73.3 to 68.0, in 0.002 M MgCl2 from 85.5 to 83.3.
2. Frequency of ingestion of chilomonads by Amoeba proteus is increased by adding strychnine sulfate to solutions of NaCl, KCl, or CaCl2. Frequency of ingestion is increased in NaCl solution from 1.3 to 2.3, in KCl from 0.75 to 2.25, and in CaCl2 from 1.1 to 1.9 chilomonads per minute. Ingestion is not significantly increased by the addition of strychnine to MgCl2 solution.
3. Frequency of ingestion of food by Amoeba proteus is not closely correlated with attachment to the substratum in NaCl and KCl solutions to which strychnine sulfate is added.
4. Chilomonads adhere to the plasmalemma of Amoeba proteus in solutions of NaCl, KCl, or CaCl2 containing strychnine, but in MgCl2 plus strychnine only a few adhere to it. Strychnine appears to make the surface of the amebae and chilomonads sticky in the former but not in the latter. Frequency of ingestion is apparently correlated with adherence of chilomonads to the plasmalemma.
5. Attachment to the substratum and ingestion by Pelomyxa carolinensis is increased by dead Chilomonas, Colpidium, and Paramecium in aqueous solutions, by materials obtained from paramecia by alcoholic-ether extraction, and by solutions in which these organisms have lived.
6. Attachment to the substratum by Pelomyxa carolinensis is not closely correlated with kind or concentration of inorganic salts used in this study.
7. Materials were found in extracts of paramecia which had certain characteristics in common with choline esters. There is no reason to doubt that under certain conditions materials are present in aqueous and alcoholic extracts which are pharmacologically similar to choline and acetylcholine.
8. Aqueous suspensions of paramecia when subcutaneously injected into young mice for 21 days inhibit the gonadotropic luteinizing hormone of the pituitary. Ovaries from injected mice showed no corpora lutea, and the seminal vesicles from injected males were smaller and contained less fluid than those of the controls.
THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR
Authors: Sollner Karl , Carr Charles W. 
Published: May 2004

1. The Teorell, Meyer-Sievers theory characterizes the electrochemical behavior of membranes by their selectivity constant "Ap" which is derived conventionally from concentration potential measurements at various concentration levels. The selectivity constant may, however, be derived also from entirely independent, different experimental data, namely base exchange studies. The constants arrived at in this second way are designated as "Ab." The selectivity constants derived by these two methods must be in reasonable, at least semiquantitative agreement if the basic assumptions of the theory are correct.
2. The selectivity constants Ap and Ab were determined for eleven different sets of membranes of different electrochemical activity and of different (8.2 to 80 volume per cent) water content.
3. The potentiometric selectivity constants Ap are in most cases several orders of magnitude greater than the corresponding Ab values. With membranes of great porosity and high electrochemical activity the Ab values approach at least in order of magnitude the Ap values.
4. It is concluded that the unexpectedly large discrepancy between the Ap and Ab values is due to some inherent weakness of the Teorell, Meyer-Sievers theory, most likely to its neglect of any structural factors.
STUDIES OF THE INNER AND OUTER PROTOPLASMIC SURFACES OF LARGE PLANT CELLS
Authors: Osterhout W. J. V. 
Published: May 2004

The vacuolar surface of Nitella is covered with a non-aqueous film too thin to be visible as a separate membrane. The motion of the protoplasm may subject this film to a good deal of mechanical disturbance.
Apparently this does not rupture the film for no dye escapes into the protoplasm as the result of such disturbance when the vacuolar sap is deeply stained with neutral red or brilliant cresyl blue.
When the deeply stained central vacuole breaks up into several smaller vacuoles, leaving the outer protoplasmic surface in its normal position, there is no evidence of the escape of dye into the protoplasm through the film surrounding the vacuole.
THE PARACRYSTALLINE STATE OF THE RAT RED CELL
Authors: Ponder Eric 
Published: May 2004

When washed rat red cells are kept in 3 per cent sodium citrate at low temperatures (4–9°C.), their resistance to osmotic hemolysis increases so that after several days they swell very little in hypotonic solutions (R = 0.15 to zero) and do not hemolyze even in distilled water. In this and in other respects they behave as if they were gelated or paracrystalline. The paracrystalline state is reversible, disappearing when the cells are warmed and rapidly reappearing when they are cooled, and the resistance to hypotonic hemolysis is not due to the cells reaching equilibrium with their environment by losing so much K that the concentrations become equal inside and out. The concentration of K remains about 25 times as great inside the cell as outside it in a hypotonic medium of T = 0.1, and the failure to swell and to hemolyze seems to be due to the activity of K in the interior of the paracrystalline cell approaching zero. The paracrystalline red cells are more resistant to saponin and digitonin hemolysis, and do not undergo the usual shape transformations, probably because they are too rigid. Hemolysis by saponin and similar lysins occurs without sphere formation, and after lysis is complete a granular debris is left behind. The paracrystalline cells show a diffuse birefringence with polarized light; on their being warmed, the birefringence disappears except at foci which are usually situated along the rim of the cell.
The occurrence of the paracrystalline state accounts for the different amounts of swelling of red cells which have been observed in systems of the same degree of hypotonicity, and its relation to other metastable states of the red cell is discussed in connection with a tabulation of the metastable states of the mammalian red cell and their relation to one another. Changes in a membrane alone seem inadequate to account for the varied phenomena observed in connection with red cell behavior, the explanation of which appears to require a more detailed knowledge of the molecular architecture of the cell interior.
OBSERVATIONS ON THE RESPIRATION OF TRYPANOSOMA CRUZI IN CULTURE
Authors: von Brand Theodor , Johnson Eleanor M. , Rees Charles W. 
Published: May 2004

1. The oxygen consumption of cultural forms of Trypanosoma cruzi decreases in intensity with increasing age of the cultures; no correlation with any other factor studied could be established.
2. The respiratory quotient was high for the first 10 days, i.e. as long as the population increased; with the onset of a decline in numbers, the R.Q. began to drop. It is believed that the flagellates consume in the beginning predominantly sugar and later predominantly protein. Observations on the pH of the cultures bear out this view.
3. The oxygen consumption was independent of the oxygen tension over a wide range of tensions.
4. The oxygen consumption increased in the temperature range 13° to 40°C., while a temperature of 44°C. proved to be lethal. Upon application of Arrhenius' equation, two straight lines, intersecting at about 28°C., resulted. The µ values were 23,980 and 5275 for the lower and higher temperature range respectively.
5. Of the oxidase inhibitors tested, strong inhibition of the oxygen consumption was achieved with azide, cyanide, and hydrogen sulfide. Pyrophosphate had no influence at all. There is some probability that cytochrome oxidase is the chief oxidase present.
6. The strongest inhibitory influence due to dehydrogenase inhibitors was observed with propyl carbamate and high concentrations of ethyl carbamate.
7. A small fraction of the oxygen consumption, about 10 per cent, may be due to substances with sulfhydryl groups, as indicated by a slight but distinct inhibition due to dilute iodoacetate and to arsenite.
SOME PROPERTIES OF PROTOPLASMIC GELS
Authors: Osterhout W. J. V. 
Published: May 2004

The chloroplasts of Nitella may contract under natural conditions as well as under the influence of certain reagents. When a sufficient amount of water enters any part of the cell they contract in that region and they expand when the direction of the current is reversed. The current may be produced by placing water at one end of the cell and applying at the other end a solution which withdraws water from the cell.
The contraction may be due to the washing out of substances from the chloroplast by the ingoing current. The outgoing current bearing dissolved materials from the sap may restore these substances and cause the chloroplasts to resume their normal shape. When blood or sodium dodecylsulfate is present in the ingoing current the contraction of the chloroplast usually fails to occur.
THE SULFONIUM SALT OF MUSTARD GAS: BIS-ß-[BIS(ß-HYDROXYETHYL) SULFONIUM] ETHYLSULFIDE DICHLORIDE (H·2TDG)
Authors: Herriott Roger M. 
Published: May 2004

1. The sulfonium salt H·2TDG is formed when H is mixed with even dilute solutions of TDG. Crystalline H·2TDG was isolated from such a reaction mixture. A simple method of preparation of this salt is outlined.
2. A material which differs from H·2TDG in that it hydrolyzes faster, is formed when H hydrolyzes in water. This material is probably H·1TDG but it was not isolated. Approximately 5 to 8 per cent of the original H is converted to this sulfonium salt.
3. The hydrolysis constant of M/100 H·2TDG has been determined at 20°, 25.5°, 37°, 75°, and 100°C., a temperature coefficient, Q10, of 3–4 was obtained. The effect of temperature is in agreement with that predicted by the Arrhenius equation. An activation energy of 26,000 calories was calculated.
THE BEHAVIOR OF THE NUCLEIC ACIDS DURING THE EARLY DEVELOPMENT OF THE SEA URCHIN EGG (ARBACIA)
Authors: Schmidt Gerhard , Hecht Liselotte , Thannhauser S. J. 
Published: May 2004

1. The unfertilized Arbacia egg contains an average of 20γ x 10–3 ribonucleic acid and 0.7 to 1γ x 10–3 desoxyribonucleic acid.
2. During the first 24 hours of development, the amount of ribonucleic acid per embryo remains practically unchanged whereas that of desoxyribonucleic acid steadily increases. At the end of this period, the amount of desoxyribonucleic acid per embryo is 10 to 15 times larger than that of the unfertilized egg.
THE EFFECTS OF LOW TEMPERATURE ON FERTILIZED RABBIT OVA IN VITRO, AND THE NORMAL DEVELOPMENT OF OVA KEPT AT LOW TEMPERATURE FOR SEVERAL DAYS
Authors: Chang M. C. 
Published: May 2004

Fertilized rabbit ova at the 2-blastomere stage kept in rabbit serum were stored at low temperatures for various lengths of time. They were then cultured at 38°C. for about 24 hours to determine their viability. A number of the viable ova were finally transplanted into recipient does.
It was found that rapid cooling of ova to 5° or to 0°C. was more harmful to the subsequent viability of ova than slow cooling. Rapid cooling was not more lethal to the ova than slow cooling, but did prevent their future normal cleavage. There was no difference between those ova cooled rapidly or slowly to 10°C. It was concluded that temperature shock has an adverse effect on ova, especially at the lower temperatures, though temperature shock can be remedied by acclimatization (slow cooling). Thus, the physiological significance of temperature shock would seem to be broadened.
The optimal temperature for the storage of ova was investigated. It was found that 10°C. was the best temperature; at this temperature viable ova were obtained after storage for 144 to 168 hours. At 0°, 5°, or 15°C. the ova were viable for 96 to 120 hours, while at 22–24°C., only for 24 to 48 hours.
The percentage of dead ova was low at a favorable temperature, increasing only at the end of the storage period. At an unfavorable temperature, however, the rate of death increased steadily from beginning to end of storage.
The percentage of abnormally cleaved ova (arrested cleavage and fragmentation) remained at a low level at first at a favorable temperature, but then increased just before or during death of the ova.
A critical time for the viability, the abnormal cleavage, and the death of ova was characteristic of each temperature.
About 24 to 28 per cent of the viable ova remaining after being stored at 0–15°C. for 2 to 4 days and cultured at 38°C. for 24 hours were capable of development into normal young.
The compatibility of serum and ova, the absence of a correlation between the viability of the ova and the source of the fertilizing spermatozoa, and the fertilization of superovulated ova (i.e., the percentage of fertile does in follicular phase and in luteal phase, the percentage of unfertilized ova and of fertilized ova at different stages, the percentage of does that had produced a normal number of ova or had produced a large number of ova, etc.), are reported.
The possibility of a more efficient utilization of the germ cells of valuable animals by means of the present techniques, and the possibility of a new approach to the experimental investigation of mammalian genetics and development, have been mentioned.
THE RELATION BETWEEN VISUAL ACUITY AND BRIGHTNESS DISCRIMINATION
Authors: Hendley Charles D. 
Published: May 2004

1. Visual acuity depends on the brightness contrast between test object and background; and conversely, brightness discrimination depends on the target size. Both functions vary with the brightness of the background. Measurements with rectangular targets of length-width ratio 2 were made over a range of sizes, contrasts, and brightnesses sufficient to determine the relations among these three variables. The rectangles were from 2' to 50' wide; the contrast fraction, ΔI/I, ranged from 0.01 to 40; the background brightness varied from 0.0001 to 2500 millilamberts.
2. When ΔI/I or visual acuity is plotted as a function of brightness the data do, in general, follow Hecht's equation. The departure from a simple photochemical theory which the larger targets show is probably due to changes in the functional retinal mosaic with changing brightness.
3. In general also, the relation between visual acuity and brightness, at selected contrasts, fits Hecht's derivation. At low contrasts, as the brightness is reduced a point is reached at which the test object becomes invisible at any size.
4. No simple relation emerges from the data relating visual acuity to contrast, at set levels of illumination. Over only a very short range are visual acuity and contrast directly related. At high contrasts, visual acuity reaches a maximum, whereas at low visual acuity, ΔI/I reaches a minimum which cannot be passed regardless of size.
5. The shape of the curves relating ΔI/I to brightness is not significantly altered by changing the exposure time. There is some evidence to show that a 3 second exposure of the target is equivalent to two looks of 0.2 second each.
6. In all these studies the thresholds were determined by a frequency of seeing method, and the data have been considered in terms of a quantum theory of threshold seeing. It was found that a threshold response involves between four and eight independent critical events, which are largely independent of size, brightness, and criterion of seeing.