scholarly journals THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR

1942 ◽  
Vol 26 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Karl Sollner ◽  
Charles W. Carr
Keyword(s):  
Oxidation State ◽  
Maximum Concentration ◽  
Structural Theory ◽  
Experimental Results ◽  
Phase Solubility ◽  
Electrical Behavior ◽  
Solution State ◽  
Homogeneous Phase ◽  
Characteristic Concentration ◽  
Strong Electrolytes

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.

scholarly journals THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR

1943 ◽  
Vol 26 (3) ◽  
pp. 309-323 ◽  
Author(s):  
Karl Sollner ◽  
Charles W. Carr
Keyword(s):  
Structural Theory ◽  
Electrochemical Activity ◽  
Electrical Behavior ◽  
Phase Theory ◽  
Varying Thickness ◽  
Maximum Value ◽  
Electrochemically Active ◽  
Concentration Potential ◽  
Characteristic Concentration ◽  
Constant Maximum

1. Experiments were carried out to decide whether or not the electromotive properties of dried collodion membranes depend upon their thickness. 2. A number of dried collodion membranes of varying thickness, 3–160 µ, were prepared from collodion preparations of different electrochemical activity. The characteristic concentration potentials across them were measured and the means of these values determined for each thickness. 3. The characteristic concentration potentials across dried collodion membranes are a function of their thickness. The thinnest membranes yield in all cases the lowest concentration potentials; increasingly thicker membranes give increasingly higher potential values, until a constant value is reached which is characteristic of the particular collodion preparation used. With electrochemically active collodion, characteristic concentration potentials approaching the thermodynamically possible maximum are obtained with membranes of only 10 µ thickness, thinner membranes giving appreciably lower values. With two rather inactive commercial collodion preparations the characteristic concentration potential increases from about 30 mv. for membranes 3 µ thick to about 42 mv. for 20 µ membranes; still thicker membranes do not show a significant increase in the potential values. With a highly purified collodion preparation the constant maximum value was found to be about 32 mv., 4 µ thick membranes giving only about 22 mv. 4. These results do not support the homogeneous phase theory as applied to the dried collodion membrane. They are readily compatible with the micellar-structural theory. Several special possible cases of the latter as applied to the dried collodion membrane are discussed.

scholarly journals THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR

1945 ◽  
Vol 28 (3) ◽  
pp. 179-185 ◽  
Author(s):  
Charles W. Carr ◽  
Harry P. Gregor ◽  
Karl Sollner
Keyword(s):  
Protamine Sulfate ◽  
Electrical Behavior ◽  
Regular Shape ◽  
Characteristic Concentration ◽  
Rotating Tubes

The technique of Abrams and Sollner for the preparation of electropositive dried protamine collodion membranes has been improved. Porous collodion membranes cast on the outside of rotating tubes are treated for 48 hours with a solution of 2 per cent protamine sulfate buffered at pH 11. After being washed thoroughly the membranes are dried in air for several hours, soaked in water for several hours, and removed from the tubes. Further drying in air but without support shrinks the membranes slightly. The resulting membranes are designated "permselective" or "megapermselective" protamine collodion membranes. These membranes regularly give characteristic concentration potentials of –52 to –53 mv. and (in 0.1 M KCl) resistance of 0.5 to 15 ohms per membrane of 50 cm.2 area. This resistance is several orders of magnitude smaller than that of the conventional dyestuff- and alkaloid-impregnated positive membranes. The megapermselective protamine collodion membranes can be kept either dry or in water for prolonged periods without detectable deterioration. They are quite smooth, have a regular shape, and stand considerable handling without breakage. The megapermselective protamine collodion membranes are the electropositive analogues of the electronegative megapermselective collodion membranes described by Carr and Sollner.

scholarly journals THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR

1944 ◽  
Vol 27 (5) ◽  
pp. 451-460 ◽  
Author(s):  
Karl Sollner ◽  
Paul W. Beck
Keyword(s):  
Citric Acid ◽  
Specific Interaction ◽  
Porous Membrane ◽  
Organic Solutes ◽  
Limited Extent ◽  
Electrical Behavior ◽  
Isobutyl Alcohol ◽  
Organic Electrolytes ◽  
Strong Electrolytes ◽  
The Ideal

1. Dried collodion membranes are known to swell in water and to the same limited extent also in solutions of strong inorganic electrolytes (Carr and Sollner). The present investigation shows that in solutions of organic electrolytes and non-electrolytes, the swelling of dried collodion membranes is not as uniform, but depends on the nature of the solute. 2. The solutions of typically "hydrophilic" substances, e.g., glycerine, glucose, and citric acid, swell collodion membranes only to the same extent as water and solutions of strong electrolytes. In solutions of typically carbophilic substances (e.g., butyric acid, valeric acid, isobutyl alcohol, valeramide, phenol, and m-nitrophenol) the swelling of the membranes is much stronger than in water, according to the concentration used. For the brand of collodion used the swelling in 0.5 M solution was in some cases as high as 26 per cent of the original volume, as compared to 6 to 7 per cent in water. Therefore, in these solutions the "water-wetted dried" collodion membrane is not rigid, inert, and non-swelling, but behaves as a swelling membrane. 3. The solutes which cause an increased swelling of the membranes are accumulated in the latter, the degree of accumulation being markedly parallel with the degree of their specific swelling action. 4. The anomalously high permeabilities of certain carbophilic organic solutes reported by Michaelis, Collander, and Höber find an explanation in the specific interaction of these substances with collodion. 5. The use of the collodion membrane as a model of the ideal porous membrane is restricted to those instances in which no specific interaction occurs between the solute and the collodion.

STUDIES ON METFORMIN HYDROCHLORIDE AND ALPHA-CYCLODEXTRIN INCLUSION COMPLEXES

2015 ◽  
Vol 1 (01) ◽  
pp. 48-53 ◽  
Author(s):  
S. Lizy Roselet, ◽  
Dr J Premakumari
Keyword(s):  
Type 2 Diabetes ◽  
Inclusion Complexes ◽  
Spectroscopic Studies ◽  
Metformin Hydrochloride ◽  
Phase Solubility ◽  
Solution State ◽  
Cyclodextrin Inclusion Complexes ◽  
Cyclodextrin Inclusion ◽  
Solubility Studies

Metformin hydrochloride is an oral antihyperglycemic drug used in the management of type-2 diabetes. Inclusion complexes were prepared between Metformin hydrochloride and alpha- cyclodextrin  in solid and solution state. Inclusion complexes were characterised using UV-VIS, Fluorescence and FTIR Spectroscopic Studies. Phase solubility studies were carried out which determined the 1:1 stoichiometry for the formation of inclusion complexes.

Quality of Refractory Materials in the Technological Process

2012 ◽  
Vol 524-527 ◽  
pp. 2026-2030
Author(s):  
Marek Šolc ◽  
Štefan Markulik ◽  
Eva Grambalová
Keyword(s):  
Experimental Data ◽  
Technological Process ◽  
Maximum Concentration ◽  
Statistical Processing ◽  
Experimental Results ◽  
Data Sets ◽  
Refractory Materials ◽  
Processing Data

In addressing issues related to technology or quality refractory products are among the supporting documents experimental results of the tests. These more or less extensive data sets characterize with some precision observed phenomenon, e.g. some physical or chemical quantity. The role of statistical processing of data from this perspective, the maximum concentration sometimes extremely abundant, but few clear set of experimental data and determine the "seriousness" of this file. When processing data it is to be noted that these characteristics are not fully observed variable, but only a selected part.

scholarly journals PHYSICOCHEMICAL CHARACTERIZATION AND EVALUATION OF TELMISARTAN: HYDROXYPROPYL-β-CYCLODEXTRIN: TWEEN 80 INCLUSION COMPLEX

2017 ◽  
Vol 9 (9) ◽  
pp. 51
Author(s):  
Poonam Arora ◽  
Jaspreet Singh ◽  
Renu Chadha
Keyword(s):  
Stability Constants ◽  
Physicochemical Characterization ◽  
Inclusion Complexation ◽  
Tween 80 ◽  
Proton Nuclear Magnetic Resonance ◽  
Phase Solubility ◽  
Scanning Calorimetry ◽  
Solution State ◽  
Presence And Absence

Objective: The present work was aimed to study the effect of the ternary component on complexation efficiency of cyclodextrins towards telmisartan which is a poorly soluble anti-hypertensive agent.Methods: The elucidation of inclusion complexation of telmisartan (TEL) with hydroxypropyl-β-cyclodextrin (HP-β-CD) in the presence and absence of tween 80 was done by investigating their interactions in solid and solution state. The solid state characterization was performed using differential scanning calorimetry (DSC), powder X-ray diffraction studies (PXRD) fourier transform infra-red spectroscopy (FTIR) studies. The host guest stoichiometry was confirmed in solution state by proton nuclear magnetic resonance (1HNMR) and solution calorimetry studies. The improvement in solubility was evaluated through dissolution studies, which was further confirmed by in vivo studies.Results: In solution state, the phase solubility studies indicated 1:1 stoichiometry between TEL and HP-β-CD both in presence and absence of tween 80. The NMR and molecular modelling studies indicated the insertion of N-methyl benzimidazole and biphenyl carboxylate regions of TEL into HP-β-CD cavity suggesting the coexistence of two 1:1 complexes in equilibrium with each other. The stability constants, K1 (imidazole region of TEL-CD) and K2 (biphenyl acetic acid region of TEL-CD), were enhanced in the presence of tween 80 as evident by the higher value of stability constants. Efficacy of ternary complex was established by a significant decrease in the systolic blood pressure of deoxycorticosterone acetate (DOCA) induced hypertensive rats.Conclusion: It can be concluded that solubility of TEL was increased by encapsulation with HP-β-CD. Tween 80 further increased the complexation efficiency and decreased the bulk of cyclodextrin.

scholarly journals THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR

1943 ◽  
Vol 27 (2) ◽  
pp. 77-89 ◽  
Author(s):  
Charles W. Carr ◽  
Karl Sollner
Keyword(s):  
Water Uptake ◽  
Pore Space ◽  
Bound Water ◽  
Weight Increase ◽  
Porous Membranes ◽  
Electrical Behavior ◽  
Volume Changes ◽  
Volume Increase ◽  
Considerable Uncertainty ◽  
Strong Electrolytes

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.

scholarly journals THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR

1941 ◽  
Vol 24 (4) ◽  
pp. 467-482 ◽  
Author(s):  
Karl Sollner ◽  
Irving Abrams ◽  
Charles W. Carr
Keyword(s):  
Sulfuric Acid ◽  
Partial Oxidation ◽  
Electrochemical Behavior ◽  
Ion Adsorption ◽  
Electrical Behavior ◽  
Strong Electrolytes ◽  
Acidic Nature ◽  
A Minor ◽  
Very High ◽  
Acid Esters

1. The electrochemical behavior of membranes prepared from commercial collodion preparations varies widely, some preparations showing very high, other ones very low electrochemical efficiency ("activity"). 2. The electrochemical activity of a collodion membrane depends entirely upon impurities of an acidic nature contained in the collodion used for casting the membrane. 3. The active acidic impurities are substantially due to partial oxidation which occurs in the manufacturing process. Sulfuric acid compounds; e.g., acid sulfuric acid esters play only a minor rôle, if any. 4. The electrochemical behavior of collodion membranes in solutions of strong electrolytes is decisively dependent upon the acidic groups built permanently into the collodion surfaces. Preferential ion adsorption plays only a minor, if any, rôle.

Zur Biogenese der Flavonoide

1961 ◽  
Vol 16 (10) ◽  
pp. 645-647 ◽  
Author(s):  
Hans Grisebach ◽  
Leni Patschke
Keyword(s):  
Oxidation State ◽  
Heterocyclic Ring ◽  
Experimental Results ◽  
Red Cabbage ◽  
Common Precursor

2′.4.4′.6′-Tetrahdroxychalcone-2′-glucoside-[β-14C] is incorporated into cyanidin in red cabbage and into cyanidin and quercetin in buckwheat. In all cases no randomization of radioactivity occurs. as was shown by degradation of the compounds. Therefore the chalcone is probably a common precursor of the anthocyanin and flavonol. Furthermore, it can be concluded from the experimental results that the oxidation state of the heterocyclic ring and ring B in the flavanoids is determined at the stage of a chalcone or of a related C15 intermediate.

Thermokinetic Propertices of CTAB on Quartz Surface and its Effects on Surface

2011 ◽  
Vol 217-218 ◽  
pp. 1449-1453
Author(s):  
Wei Dong Liu ◽  
Ling Hui Sun
Keyword(s):  
Aqueous Solution ◽  
Adsorption Mechanism ◽  
Experimental Results ◽  
Surface Wettability ◽  
Thermokinetic Parameters ◽  
Quartz Surface ◽  
Electrical Behavior ◽  
Adsorption Enthalpy ◽  
Wetting Behavior ◽  
Enthalpy And Entropy

In this study, the adsorption mechanism of cethyltrimethylammounium bromide (CTAB) onto quartz surface from aqueous solution was investigated and also some thermokinetic parameters such as isosteric adsorption enthalpy and entropy for this system were determined through thermogenesis curves determination by microcalorimetry. In addition, the contribution of adsorption to the surface wettability is illustrated according to the experimental results of surface electrical behavior and wetting behavior. This study shows that the wetting behavior of CTAB on quartz surface is determined by the process of its adsorption.

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