Hydrates of adenosine 3′,5′-cyclic monophosphate sodium and their transformation

CrystEngComm ◽  
2021 ◽  
Vol 23 (1) ◽  
pp. 174-184
Author(s):  
Pengpeng Yang ◽  
Junyang Jin ◽  
Qingshi Wen ◽  
Chenguang Lin ◽  
JinQiu Fu ◽  
...  
Keyword(s):  
Steric Effects ◽  
Crystal Water ◽  
Reversible Transformation ◽  
Cyclic Monophosphate ◽  
Host Structure ◽  
The Difference

The difference of crystal water behaviors for cAMPNa hydrates was attributed mainly to the steric effects in lattices. Excessive loss of crystal water would destroy the host structure, and result in the disability of reversible transformation.

Ortho Effect in Dissociation of Substituted N-Phenylbenzenesulfonamides

2001 ◽  
Vol 66 (9) ◽  
pp. 1380-1392 ◽  
Author(s):  
Jiří Nádvorník ◽  
Miroslav Ludwig
Keyword(s):  
Experimental Data ◽  
Latent Variables ◽  
Dissociation Constants ◽  
Substituent Effects ◽  
Principal Component ◽  
Steric Effects ◽  
Deviation Analysis ◽  
Acid Base Equilibrium ◽  
The Difference ◽  
Electronic And Steric Effects

Twenty-five 2,2'-disubstituted N-phenylbenzenesulfonamides (2-X-C6H4SO2NHC6H4-Y-2') were synthesised and their purity checked by elemental analysis. This set of model substrates involved all possible combinations of methoxy, methyl, hydrogen, chloro, and nitro substituents. The dissociation constants of the sulfonamides were determined by potentiometric titration in methanol, pyridine, dimethyl sulfoxide, N,N-dimethylformamide, acetone, and acetonitrile. The dissociation constants pKHA obtained were correlated with various sets of substituent constants describing electronic and steric effects of the substituents, and the statistically treated data were used to discuss the contribution of the substituent effects in the dissociation and the difference between the effects transmitted from the two rings. A linear regression model explaining 99% of the variability of experimental data in all the solvents has been found and discussed. Moreover, the experimental data were also interpreted by the methods using latent variables, the principal component analysis (PCA) and conjugated deviation analysis (CDA), and two latent variables were shown to be statistically significant in the description of dissociation. The first obviously describes common action of electronic and steric effects of substituents; the other probably concerns a combined effect of substituent and solvent on the position of acid-base equilibrium.

On the positional reactivity order in the sulfuric acid sulfonation of the two naphthalenesulfonic acids

1983 ◽  
Vol 61 (7) ◽  
pp. 1453-1455 ◽  
Author(s):  
Peter de Wit ◽  
Hans Cerfontain
Keyword(s):  
Sulfuric Acid ◽  
Sulfonic Acid ◽  
Steric Effects ◽  
Disulfonic Acid ◽  
Acid Mixture ◽  
Aqueous Sulfuric Acid ◽  
The Difference ◽  
Reactivity Order ◽  
Electronic And Steric Effects

The sulfonation in 98.5% H2SO4 at 25.0 °C of naphthalene-1-sulfonic acid yields 58% 1,5-, 32% 1,6-, and 10% 1,7-disulfonic acids and that of the 2-sulfonic acid 4% 1,3-, 74% 1,6-, 18% 1,7-, and 4% 2,6- + 2,7-disulfonic acids. Further sulfonation of the latter disulfonic acid mixture in 105.2% H2SO4 at 25.0 °C yields 78% 1,3,6- and 12% 1,3,5- + 1,3,7-trisulfonic acids. Reaction of naphthalene-1,5-disulfonic acid with 105.2% H2SO4 at 25 °C yields 5-sulfonaphthalene-1-sulfonic anhydride.Partial rate factors for the sulfonation of naphthalene-1- and -2-sulfonate in highly concentrated aqueous sulfuric acid (where the sulfonating entity is H2S2O7) are reported. They are discussed in terms of the difference in the reactivity of the α- and β-positions of the naphthalene skeleton and the electronic and steric effects of the sulfonate substituent already present.

Effects of CGRP, forskolin, PMA, and ionomycin on pHi dependence of Na-H exchange in UMR-106 cells

1994 ◽  
Vol 266 (4) ◽  
pp. C1083-C1092 ◽  
Author(s):  
Anandarup Gupta ◽  
Christof J. Schwiening ◽  
Walter F. Boron
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Acid Base Balance ◽  
Total Acid ◽  
Molecular Physiology ◽  
Cyclic Monophosphate ◽  
Kinase C ◽  
Base Balance ◽  
The Difference ◽  
Umr 106

1 Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510 We examined the effects of calcitonin gene-related peptide (CGRP), forskolin, phorbol 12-myristate 13-acetate (PMA), and ionomytin on the intracellular pH (pHi) dependence of Na-H exchange in UMR-106 cells. In the nominal absence of CO2-HCO3-, each agent increased pHi, measured with 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF). From the rate of pHi recovery (dpHi/dt) from an acid load, and intracellular buffering power, we computed the pHi dependence of the total acid-extruding flux (JTotal). All four agents increased JTotal. From dpHi/dt data obtained in the presence of ethylisopropyl amiloride (EIPA, a blocker of Na-H exchange), we determined the EIPA-resistant component of JTotal (JEIPA/R). We estimated the Na-H exchange flux (JNa-H as the difference JTotal - JEIPA/R. CGRP, forskolin, and PMA produced similar increases in the slope of the JNa-H vs. pHi-relationship. The net effect of these agents, as well as ionomycin, was to increase JNa-H over a broad pHi range. Ionomycin alkaline shifted the JEIPA/R vs. pHi relationship; the other agents had no effect. Our results indicate that CGRP increased JTotal by stimulating Na-H exchange, with little effect on EIPA-resistant processes. A signaling pathway involving only adenosine 3',5'-cyclic monophosphate, only protein kinase C, or only Ca2+ cannot account for the effects of CGRP on both pHi and pHi dependence of JNa-H. Thus, CGRP probably affects UMR-106 pHi physiology via more than one pathway. acid-base balance; ion transport; ethylisopropyl amiloride; amiloride analogs; osteoblasts; fluorescence; 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein; calcium; adenosine 3',5'-cyclic monophosphate; protein kinase C Submitted on February 19, 1993 Accepted on October 8, 1993

Structural investigations of phosphorus–nitrogen compounds. 4. Steric and electronic effects in dibenzylamino derivatives of hexachlorocyclotriphosphazatriene and 4,4,6,6-tetrachloro-2,2-diphenylcyclotriphosphazatriene

2002 ◽  
Vol 58 (3) ◽  
pp. 545-552 ◽  
Author(s):  
Serap Beşli ◽  
Simon J. Coles ◽  
David B. Davies ◽  
Michael B. Hursthouse ◽  
Adem Kılıç ◽  
...  
Keyword(s):  
Secondary Amine ◽  
Systematic Study ◽  
Steric Effects ◽  
Nitrogen Compounds ◽  
Electronic Contribution ◽  
Electronic Effects ◽  
Structural Investigations ◽  
Bond Lengths ◽  
The Difference ◽  
Derivatives Of

A systematic study is presented on the products of aminolysis of N3P3Cl6 (1) and N3P3Ph2Cl4 (4) with dibenzylamine. Two series of mono- and disubstituted derivatives of compounds (1) and (4), namely N3P3Cl5[N(CH2Ph)2] (2) and N3P3Cl4[N(CH2Ph)2]2 (3) and N3P3Ph2Cl3[N(CH2Ph)2] (5) and N3P3Ph2Cl2[N(CH2Ph)2]2 (6) [where (2), (3), (5) and (6) are new structures], are investigated in order to determine whether steric or electronic effects prevail in the formation of dibenzylamino-substituted cyclophosphazenes. The influence of an electron-releasing group (i.e. phenyl) on the stereochemistry and degree of substitution of the product is analysed by comparison of the above two series. The difference in unsymmetrically substituted endocyclic P—N bond lengths, Δ, is used as a measure of the degree of the electronic contribution, in combination with basicity constants, to quantify the degree of the electron-releasing capacity of the R group. In order to compare geminal versus non-geminal substitution, a difunctional secondary amine was used to form the compound N3P3Cl4[NMe(CH2)3NMe] (7) (a reinvestigation) for inclusion in this study. It is shown that electron-releasing groups have a greater effect on the lengthening of P—Cl bonds as opposed to endocyclic P—N bonds and that this effect is greater in the non-geminal PRCl case than for geminal PCl2. However, steric effects are shown to be dominant in the reactions of dibenzylamine with N3P3 derivatives, with a disposition to a trans stereochemistry in bisdibenzylamino derivatives.

The Origin of the Moon

1962 ◽  
Vol 14 ◽  
pp. 149-155 ◽  
Author(s):  
E. L. Ruskol
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
The Moon ◽  
The Earth ◽  
The Difference ◽  
Origin Of The Moon

The difference between average densities of the Moon and Earth was interpreted in the preceding report by Professor H. Urey as indicating a difference in their chemical composition. Therefore, Urey assumes the Moon's formation to have taken place far away from the Earth, under conditions differing substantially from the conditions of Earth's formation. In such a case, the Earth should have captured the Moon. As is admitted by Professor Urey himself, such a capture is a very improbable event. In addition, an assumption that the “lunar” dimensions were representative of protoplanetary bodies in the entire solar system encounters great difficulties.

Influence of Cell Wall Composition on the Fossilisation of Bacteria and the Implications for the Search for Early Life Forms

1997 ◽  
Vol 161 ◽  
pp. 491-504 ◽  
Author(s):  
Frances Westall
Keyword(s):  
Cell Wall ◽  
Life Forms ◽  
Cation Binding ◽  
Positive Bacterium ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Transmission Electron ◽  
Hydrothermal Sediments ◽  
Identification Of Bacteria ◽  
The Difference

AbstractThe oldest cell-like structures on Earth are preserved in silicified lagoonal, shallow sea or hydrothermal sediments, such as some Archean formations in Western Australia and South Africa. Previous studies concentrated on the search for organic fossils in Archean rocks. Observations of silicified bacteria (as silica minerals) are scarce for both the Precambrian and the Phanerozoic, but reports of mineral bacteria finds, in general, are increasing. The problems associated with the identification of authentic fossil bacteria and, if possible, closer identification of bacteria type can, in part, be overcome by experimental fossilisation studies. These have shown that not all bacteria fossilise in the same way and, indeed, some seem to be very resistent to fossilisation. This paper deals with a transmission electron microscope investigation of the silicification of four species of bacteria commonly found in the environment. The Gram positiveBacillus laterosporusand its spore produced a robust, durable crust upon silicification, whereas the Gram negativePseudomonas fluorescens, Ps. vesicularis, andPs. acidovoranspresented delicately preserved walls. The greater amount of peptidoglycan, containing abundant metal cation binding sites, in the cell wall of the Gram positive bacterium, probably accounts for the difference in the mode of fossilisation. The Gram positive bacteria are, therefore, probably most likely to be preserved in the terrestrial and extraterrestrial rock record.

Structuring, Motions and Shapes of Corona Emission Line Profiles

1994 ◽  
Vol 144 ◽  
pp. 421-426
Author(s):  
N. F. Tyagun
Keyword(s):  
Emission Line ◽  
Filling Factor ◽  
Direct Relationship ◽  
Coronal Plasma ◽  
Line Of Sight ◽  
Line Profiles ◽  
The Difference ◽  
Yellow Line ◽  
Red Line

AbstractThe interrelationship of half-widths and intensities for the red, green and yellow lines is considered. This is a direct relationship for the green and yellow line and an inverse one for the red line. The difference in the relationships of half-widths and intensities for different lines appears to be due to substantially dissimilar structuring and to a set of line-of-sight motions in ”hot“ and ”cold“ corona regions.When diagnosing the coronal plasma, one cannot neglect the filling factor - each line has such a factor of its own.

Difference Fourier Analysis of Glucose Embedded and Frozen Hydrated Purple Membrane

1982 ◽  
Vol 40 ◽  
pp. 74-75
Author(s):  
Jules S. Jaffe ◽  
Robert M. Glaeser
Keyword(s):  
Purple Membrane ◽  
Data Set ◽  
High Resolution Data ◽  
X Ray ◽  
X Ray Crystallography ◽  
Fourier Techniques ◽  
Versus Protein ◽  
The Difference ◽  
Difference Fourier ◽  
Ideal Method

Although difference Fourier techniques are standard in X-ray crystallography it has only been very recently that electron crystallographers have been able to take advantage of this method. We have combined a high resolution data set for frozen glucose embedded Purple Membrane (PM) with a data set collected from PM prepared in the frozen hydrated state in order to visualize any differences in structure due to the different methods of preparation. The increased contrast between protein-ice versus protein-glucose may prove to be an advantage of the frozen hydrated technique for visualizing those parts of bacteriorhodopsin that are embedded in glucose. In addition, surface groups of the protein may be disordered in glucose and ordered in the frozen state. The sensitivity of the difference Fourier technique to small changes in structure provides an ideal method for testing this hypothesis.

Destruction of Actin Filaments by Osmium Tetroxide

1977 ◽  
Vol 35 ◽  
pp. 466-467
Author(s):  
P. Maupin-Szamier ◽  
T. D. Pollard
Keyword(s):  
Actin Filaments ◽  
Time Course ◽  
Osmium Tetroxide ◽  
Rabbit Muscle ◽  
Muscle Actin ◽  
Sodium Phosphate Buffer ◽  
Transmission Electron ◽  
The Difference ◽  
Rates Of Decay ◽  
Short Time

We have studied the destruction of rabbit muscle actin filaments by osmium tetroxide (OSO4) to develop methods which will preserve the structure of actin filaments during preparation for transmission electron microscopy.Negatively stained F-actin, which appears as smooth, gently curved filaments in control samples (Fig. 1a), acquire an angular, distorted profile and break into progressively shorter pieces after exposure to OSO4 (Fig. 1b,c). We followed the time course of the reaction with viscometry since it is a simple, quantitative method to assess filament integrity. The difference in rates of decay in viscosity of polymerized actin solutions after the addition of four concentrations of OSO4 is illustrated in Fig. 2. Viscometry indicated that the rate of actin filament destruction is also dependent upon temperature, buffer type, buffer concentration, and pH, and requires the continued presence of OSO4. The conditions most favorable to filament preservation are fixation in a low concentration of OSO4 for a short time at 0°C in 100mM sodium phosphate buffer, pH 6.0.

Antiphase Boundaries in Ordered Ni3FE Crystals

1969 ◽  
Vol 27 ◽  
pp. 62-63
Author(s):  
Y. H. Liu
Keyword(s):  
Domain Size ◽  
Antiphase Domain ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hardening Mechanism ◽  
Superlattice Structure ◽  
Disordered Phase ◽  
Domain Boundaries ◽  
Atomic Scattering ◽  
The Difference

Ordered Ni3Fe crystals possess a LI2 type superlattice similar to the Cu3Au structure. The difference in slip behavior of the superlattice as compared with that of a disordered phase has been well established. Cottrell first postulated that the increase in resistance for slip in the superlattice structure is attributed to the presence of antiphase domain boundaries. Following Cottrell's domain hardening mechanism, numerous workers have proposed other refined models also involving the presence of domain boundaries. Using the anomalous X-ray diffraction technique, Davies and Stoloff have shown that the hardness of the Ni3Fe superlattice varies with the domain size. So far, no direct observation of antiphase domain boundaries in Ni3Fe has been reported. Because the atomic scattering factors of the elements in NijFe are so close, the superlattice reflections are not easily detected. Furthermore, the domain configurations in NioFe are thought to be independent of the crystallographic orientations.

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