Thermodynamics of ionization of aqueous toluidinium ions

1968 ◽  
Vol 46 (12) ◽  
pp. 1965-1967 ◽  
Author(s):  
W. F. O'Hara
Keyword(s):  
Free Energy ◽  
High Precision ◽  
Linear Relation ◽  
Solution Calorimeter ◽  
Thermodynamics Of Ionization

Standard heats of ionization of ortho-, meta-, and para-toluidinium ions in water at 25 °C have been determined in a high precision solution calorimeter. Entropies of ionization have been calculated from these heats and well-defined free energy changes. As predicted by theory, a linear relation is found between ΔS0Ion and ΔG0Ion and between ΔH0Ion and ΔS0Ion for these compounds.

Inhibition of short-circuit current in rat ileum by aliphatic alcohols

1984 ◽  
Vol 247 (5) ◽  
pp. G547-G552
Author(s):  
Y. Fernandez ◽  
J. F. Desjeux ◽  
A. M. Dumontier ◽  
S. Mitjavila
Keyword(s):  
Free Energy ◽  
Intestinal Epithelium ◽  
Linear Relation ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Active Sodium ◽  
Rat Ileum ◽  
Functional Activities ◽  
Hydrophobic Nature ◽  
Stimulation Of

The importance of the hydrophobic nature of the membrane in certain functions of the intestinal epithelium was investigated by determining the variations in short-circuit current (Isc), potential difference (PD), and conductance (G) in rat ileum in the presence of the first eight alcohols in the n-aliphatic series. At the lowest alcohol concentrations and in the presence of Ringer-galactose, there was transitory stimulation of Isc and PD that did not occur in the presence of theophylline or in the absence of chloride. With or without theophylline all the alcohols tested inhibited Isc and PD and slightly increased G as a function of their concentration. The modifications in Isc were attributed to the inhibition of active sodium transport. These results demonstrate a linear relation between the logarithm of the concentrations causing 50% inhibition of Isc and the chain length of the alcohols. The variations in free energy required to transfer one -CH2- to the site at which the alcohols exert their activity were, respectively, -582 and -589 cal in the presence and absence of theophylline. These values show that the observed modifications in free energy are due to solubilization of the alcohols in a very hydrophobic zone of the tissue, confirming that the functional activities measured are dependent on the hydrophobicity of the membrane.

STUDIES ON THE THERMODYNAMICS AND CONDUCTANCES OF MOLTEN SALTS AND THEIR MIXTURES: PART II. THE VISCOSITIES, HEATS OF FUSION, AND HEAT CAPACITIES OF LITHIUM CHLORATE AND LITHIUM CHLORATE–LITHIUM NITRATE MIXTURES

1964 ◽  
Vol 42 (7) ◽  
pp. 1616-1626 ◽  
Author(s):  
A. N. Campbell ◽  
M. K. Nagarajan
Keyword(s):  
Free Energy ◽  
High Precision ◽  
Molten Salts ◽  
Heat Capacities ◽  
Liquid Lithium ◽  
Lithium Nitrate ◽  
Transition Formula ◽  
Different Temperatures ◽  
Molten Lithium ◽  
The Difference

The viscosities at different temperatures of pure molten lithium chlorate and of mixtures of lithium chlorate with lithium nitrate have been determined with high precision. The heats of fusion, and the molar heat capacities of both solid and liquid lithium chlorate, and of mixtures of lithium chlorate and lithium nitrate have also been determined. The heat of the transition [Formula: see text] has been obtained as the difference between the heats of solution in water of the two forms. The enthalpy, free energy, and entropy of mixing have been derived.

Reactivity differences between haemoglobins. II. Electrostatic contribution to the free energy and enthalpy of ionization of methaemoglobins

1964 ◽  
Vol 277 (1370) ◽  
pp. 414-422 ◽  
Keyword(s):  
Free Energy ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Linear Relation ◽  
Electrostatic Interactions ◽  
Free Energies ◽  
Reactive Site ◽  
Electrostatic Contribution ◽  
Enthalpy Of Ionization

It was concluded in part I that the differences between the free energies, enthalpies, and entropies of ionization of methaem oglobins A, S , and C are the result of different electrostatic interactions between the protein and the reactive site, and that this arises because of the small differences in their amino acid composition. In this paper the electrostatic contribution to the differences in the free energies of ionizations are calculated, using as a basis for calculation Kirkwood’s model for a protein. These calculations show that the observed differences in free energies may be accounted for quantitatively by the different electrostatic interactions between the protein and reactive site for the three methaemoglobins. The linear relation between Δ H ° and T Δ S °, reported in part I, is also shown to be the consequence of the electrostatic origin of the differences between these quantities. Other abnormal haemoglobins are considered in the light of the conclusions reached in this paper, and predictions are made concerning the thermodynamics of ionizations of their met forms.

Linear Free Energy Relationship Involving the Properties of Prevulcanization Inhibitors

1982 ◽  
Vol 55 (2) ◽  
pp. 352-362
Author(s):  
E. Morita
Keyword(s):  
Free Energy ◽  
13C Nmr ◽  
Linear Relation ◽  
Linear Free Energy Relationship ◽  
Linear Free Energy ◽  
Structural Types ◽  
Alkyl Groups ◽  
Rate Of Reaction ◽  
Hammett Σ Constants ◽  
Relationship Of

Abstract The utilization of σ* constants for substituted phenyl groups converted from the known Hammett σ constants of the phenyl substituents is useful in assessing the linear free energy relationship (LFER) of the properties of various inhibitors. The inhibitors include thioketals, sulfenamides and N,N′thiobis(substituted formanilides). In the LFER of the rate of reaction between thioketals with 2-mercaptobenzothiazole, the rate is fastest when the thio group of the thioketal is attached to a substituted phenyl with the highest positive σ constant. The σ constant of alkyl groups is negative, and an alkylthio group gives a thioketal with a slower reaction rate. The LFER applies to the 13C NMR shift of the quaternary carbon of the thioketals with alkylthio groups. The slope of the linear relation is positive. However, changes in the 13C NMR shift of the arylthio derivatives are relatively small in spite of a wide variation in σ* constant. The LFER applies to the scorch delaying activities of all structural types of inhibitors in stocks accelerated by various benzothiazoles. In the linear relationship of scorch delay versus σ* constant in each type of inhibitor, the slope is negative. Variables with negative σ* constants give longer delay and those with more positive σ* constants give shorter delay. An exception is in the very fast curing MSSM/DPG stock where the thioketals from acetoacetanilide with arylthio groups give longer delay than the alkylthio compounds. In the TBBS-accelerated stock, the slopes of the linear relation of the carbamate sulfenamides, N,N′-thiobisformanilides and thioketals of cyanoacetanilides are about equal. However, the level of scorch delay obtained with the sulfenamides is significantly higher than the other two, which are equal in inhibition level. The inhibition action of N,N′-thiobisformanilides without alkylthio or arylthio groups is probably due to the formation of labile formanilide polysulfide intermediates.

Encultured minds, not error reduction minds

2020 ◽  
Vol 43 ◽  
Author(s):  
Robert Mirski ◽  
Mark H. Bickhard ◽  
David Eck ◽  
Arkadiusz Gut
Keyword(s):  
Free Energy ◽  
Error Reduction ◽  
Energy Principle ◽  
Free Energy Principle ◽  
Current Article

Abstract There are serious theoretical problems with the free-energy principle model, which are shown in the current article. We discuss the proposed model's inability to account for culturally emergent normativities, and point out the foundational issues that we claim this inability stems from.

Automatic measurement of SAED patterns from asbestos minerals

1988 ◽  
Vol 46 ◽  
pp. 846-847
Author(s):  
J. C. Russ ◽  
T. Taguchi ◽  
P. M. Peters ◽  
E. Chatfield ◽  
J. C. Russ ◽  
...  
Keyword(s):  
Diffraction Pattern ◽  
High Precision ◽  
Diffraction Data ◽  
Automatic Measurement ◽  
Automatic Method ◽  
Important Method ◽  
X Ray ◽  
Integrated Intensity ◽  
Asbestiform Minerals ◽  
True Center

Conventional SAD patterns as obtained in the TEM present difficulties for identification of materials such as asbestiform minerals, although diffraction data is considered to be an important method for making this purpose. The preferred orientation of the fibers and the spotty patterns that are obtained do not readily lend themselves to measurement of the integrated intensity values for each d-spacing, and even the d-spacings may be hard to determine precisely because the true center location for the broken rings requires estimation. We have implemented an automatic method for diffraction pattern measurement to overcome these problems. It automatically locates the center of patterns with high precision, measures the radius of each ring of spots in the pattern, and integrates the density of spots in that ring. The resulting spectrum of intensity vs. radius is then used just as a conventional X-ray diffractometer scan would be, to locate peaks and produce a list of d,I values suitable for search/match comparison to known or expected phases.

On effects of non-systematic reflections on weak-beam images of partial dislocations

1991 ◽  
Vol 49 ◽  
pp. 688-689
Author(s):  
K. Z. Botros ◽  
S. S. Sheinin
Keyword(s):  
High Precision ◽  
Stacking Fault ◽  
Important Application ◽  
Stacking Fault Energy ◽  
Sharp Peak ◽  
Weak Beam ◽  
Partial Dislocations ◽  
Deviation Parameter ◽  
Beam Diffraction

The main features of weak beam images of dislocations were first described by Cockayne et al. using calculations of intensity profiles based on the kinematical and two beam dynamical theories. The feature of weak beam images which is of particular interest in this investigation is that intensity profiles exhibit a sharp peak located at a position very close to the position of the dislocation in the crystal. This property of weak beam images of dislocations has an important application in the determination of stacking fault energy of crystals. This can easily be done since the separation of the partial dislocations bounding a stacking fault ribbon can be measured with high precision, assuming of course that the weak beam relationship between the positions of the image and the dislocation is valid. In order to carry out measurements such as these in practice the specimen must be tilted to "good" weak beam diffraction conditions, which implies utilizing high values of the deviation parameter Sg.

Digital differential hysteresis iimage processing displays what the microscope acquires but the eye can't see

1995 ◽  
Vol 53 ◽  
pp. 642-643
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
Image Processing ◽  
Visual System ◽  
High Precision ◽  
Image Data ◽  
Processing Technology ◽  
Output Data ◽  
Contrast Resolution ◽  
Pixel Intensity ◽  
Data Reading ◽  
Hysteresis Properties

Differential hysteresis processing is a new image processing technology that provides a tool for the display of image data information at any level of differential contrast resolution. This includes the maximum contrast resolution of the acquisition system which may be 1,000-times higher than that of the visual system (16 bit versus 6 bit). All microscopes acquire high precision contrasts at a level of <0.01-25% of the acquisition range in 16-bit - 8-bit data, but these contrasts are mostly invisible or only partially visible even in conventionally enhanced images. The processing principle of the differential hysteresis tool is based on hysteresis properties of intensity variations within an image.Differential hysteresis image processing moves a cursor of selected intensity range (hysteresis range) along lines through the image data reading each successive pixel intensity. The midpoint of the cursor provides the output data. If the intensity value of the following pixel falls outside of the actual cursor endpoint values, then the cursor follows the data either with its top or with its bottom, but if the pixels' intensity value falls within the cursor range, then the cursor maintains its intensity value.

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