scholarly journals Effects of pH and Ionic Strength on the Stability of Nanobubbles in Aqueous Solutions of α-Cyclodextrin

2007 ◽  
Vol 111 (40) ◽  
pp. 11745-11749 ◽  
Author(s):  
Fan Jin ◽  
Junfang Li ◽  
Xiaodong Ye ◽  
Chi Wu
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Effects Of Ph ◽  
The Stability

scholarly journals Stability of Secondary and Tertiary Structures of Virus-Like Particles Representing Noroviruses: Effects of pH, Ionic Strength, and Temperature and Implications for Adhesion to Surfaces

2015 ◽  
Vol 81 (22) ◽  
pp. 7680-7686 ◽  
Author(s):  
Idrissa Samandoulgou ◽  
Riadh Hammami ◽  
Rocio Morales Rayas ◽  
Ismail Fliss ◽  
Julie Jean
Keyword(s):  
Ionic Strength ◽  
Structural Rearrangement ◽  
Tertiary Structures ◽  
Hydrophobic Residues ◽  
Virus Like Particles ◽  
Nacl Concentration ◽  
Effects Of Ph ◽  
The Stability ◽  
Α Helix ◽  
Fresh Foods

ABSTRACTLoss of ordered molecular structure in proteins is known to increase their adhesion to surfaces. The aim of this work was to study the stability of norovirus secondary and tertiary structures and its implications for viral adhesion to fresh foods and agrifood surfaces. The pH, ionic strength, and temperature conditions studied correspond to those prevalent in the principal vehicles of viral transmission (vomit and feces) and in the food processing and handling environment (pasteurization and refrigeration). The structures of virus-like particles representing GI.1, GII.4, and feline calicivirus (FCV) were studied using circular dichroism and intrinsic UV fluorescence. The particles were remarkably stable under most of the conditions. However, heating to 65°C caused losses of β-strand structure, notably in GI.1 and FCV, while at 75°C the α-helix content of GII.4 and FCV decreased and tertiary structures unfolded in all three cases. Combining temperature with pH or ionic strength caused variable losses of structure depending on the particle type. Regardless of pH, heating to pasteurization temperatures or higher would be required to increase GII.4 and FCV adhesion, while either low or high temperatures would favor GI.1 adhesion. Regardless of temperature, increased ionic strength would increase GII.4 adhesion but would decrease GI.1 adhesion. FCV adsorption would be greater at refrigeration, pasteurization, or high temperature combined with a low salt concentration or at a higher NaCl concentration regardless of temperature. Norovirus adhesion mediated by hydrophobic interaction may depend on hydrophobic residues normally exposed on the capsid surface at pH 3, pH 8, physiological ionic strength, and low temperature, while at pasteurization temperatures it may rely more on buried hydrophobic residues exposed upon structural rearrangement.

scholarly journals Thermodynamics of binary and ternary complexes of 3-amino-1, 2, 4-triazole and aminoacids with Ni(II) and Co(II) metal ions

2005 ◽  
Vol 70 (8-9) ◽  
pp. 1057-1066 ◽  
Author(s):  
Ayse Erçag ◽  
Tuba Sismanoglu ◽  
Suheyla Pura
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Glutamic Acid ◽  
Driving Force ◽  
Ternary Complex ◽  
Ternary Complexes ◽  
Binary And Ternary Complexes ◽  
Enthalpy Changes ◽  
Binary Complexes ◽  
The Stability

The stability constants of the 1:1 binary complexes of Ni(II) and Co(II) with 3-amino-1,2,4-triazole (AT), leucine (Leu) and glutamic acid (Glu), and the 1:1:1 ternary complex of them and the protonation constants of the ligands were determined potentiometrically at a constant ionic strength of I = 0.10 mol L-1 (NaClO4) in aqueous solutions at 15.0 and 25.0 ?C. The thermodynamic parameters ?Gf0, ?Hf0 and ?Sf0 are reported for the formation reactions of the complexes. The enthalpy changes of all the complexations were found to be negative but the entropy changes positive. While the driving force for the formation of the Ni(II), Co(II) ? AT complexes is the enthalpy decrease, the driving force for the ternary complexes of AT is the entropy increase.

THE STABILITY OF THIOCOMPLEXES AND SOLUBILITY PRODUCTS OF METAL SULPHIDES: I. CADMIUM SULPHIDE

1964 ◽  
Vol 42 (3) ◽  
pp. 662-668 ◽  
Author(s):  
J. Ste-Marie ◽  
A. E. Torma ◽  
A. O. Gübeli
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Total Concentration ◽  
Cadmium Sulphide ◽  
Radioactive Tracer ◽  
Tracer Technique ◽  
Radioactive Tracer Technique ◽  
Ph Values ◽  
Solubility Products ◽  
The Stability

The nature and stability of cadmium sulphide complexes in aqueous solutions have been investigated. The total concentration of the metal in solution was determined at constant temperature and ionic strength, and at various pH values, by a radioactive tracer technique.

scholarly journals Activity corrections for ionic equilibria in aqueous solutions

1980 ◽  
Vol 58 (12) ◽  
pp. 1253-1257 ◽  
Author(s):  
Mian S. Sun ◽  
Donald K. Harriss ◽  
Vincent R. Magnuson
Keyword(s):  
Ionic Strength ◽  
Stability Constant ◽  
Aqueous Solutions ◽  
General Formula ◽  
Stability Constants ◽  
Ionic Equilibria ◽  
Ion Activity ◽  
The Difference ◽  
Single Ion Activity ◽  
The Stability

Activity corrections for ionic equilibria in aqueous solutions at 25 °C and ionic strengths up to 0.5 have been investigated. An empirical formula for activity corrections was generated by statistically fitting stability constant data for approximately 540 complexes, for which both thermodynamic and concentration stability constants were known, to a modified Debye – Hückel relationship. The general formula is[Formula: see text]χ > 0, where Δ log K is the difference in the logarithms of the stability constants at infinite dilution and finite I (I ≤ 0.5), and χ is an even integer dependent only on the stoichiometry and charge of the ions involved. Activity correction formulae for ionic equilibria involving classes of ligands (amino acid, inorganic, amine, and organic acid) also were developed. The general formula predicts stability constant corrections within 0.1 log unit for 87 % of the data used at ionic strength 0.1 and 64 % of the data at ionic strength 0.5. In addition, single ion activity coefficients as a function of ionic strength, 0 < I ≤ 0.5, are presented.

Solvent Extraction of Mono(salicylato)beryllium, and the pH Titration of the System Beryllium-Salicylic Acid

1962 ◽  
Vol 15 (2) ◽  
pp. 218 ◽  
Author(s):  
Bruin HJ de ◽  
D Kairaitis ◽  
L Szego
Keyword(s):  
Salicylic Acid ◽  
Ionic Strength ◽  
Solvent Extraction ◽  
Aqueous Solutions ◽  
Distribution Ratio ◽  
Free Ligand ◽  
Ph Titration ◽  
Maximum Value ◽  
The Stability ◽  
Beryllium Complexes

It has been shown that a salicylatoberyllium complex can be extracted from aqueous solutions by aliphatic alcohols. The distribution ratio is a symmetrical function of the logarithm of the free ligand concentration and passes through a maximum value ; the stability constants of the mono- and bis(salicylato)beryllium complexes have been determined from the data for points of equal extraction. The values obtained in this way are β1 = 4.1 x 1012 and β2 = 4.3 x 1022, in an ionic strength of 0.15. They agree fairly well with those obtained by pH-titration procedures, which are β1 = 6.1 x 1012 and β2 =7 x 1022.

Extraction of some metals into solutions of 1-phenyl-3-methyl-4-benzoylpyrazolone-5 in freon 113

1980 ◽  
Vol 45 (4) ◽  
pp. 1221-1226 ◽  
Author(s):  
Oldřich Navrátil ◽  
Pavel Linhart
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Stability Constants ◽  
Aqueous Phase ◽  
Organic Phase ◽  
Extraction Constants ◽  
Distribution Constants ◽  
The Stability

The partition of 1-phenyl-3-methyl-4-benzoylpyrazolone-5 (HA) between aqueous solutions of HClO4 and NaClO4, ionic strength 0.1, and Freon 113 or its 2 : 1 mixture with benzene was studied. The logarithms of the HA distribution constants are 2.84 ± 0.10 and 3.39 ± 0.15 for the two organic phases, respectively. The extraction curves of cerium(III) and europium(III) revealed that in dependence on the pH of the aqueous phase, the metals are transferred into the organic phase in the form of the MA3 complexes (M = Ce, Eu). The stability constants of the complexes MAn in the aqueous phase were determined along with their distribution and extraction constants. For cobalt, zinc, and hafnium, a part of the extraction curves could only be studied, only the extraction constants were therefore determined. The sparing solubility of HA in Freon 113 can be circumvented by using a Freon-benzene mixture 2 : 1, which is still practically incombustible.

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