The Coagulability of Partially Lysed Fibrinogen Effect of pH and Ionic Strength

1971 ◽  
Vol 25 (02) ◽  
pp. 346-353 ◽  
Author(s):  
D. C Triantaphyllopoulos ◽  
Mary Torres
Keyword(s):  
Ionic Strength ◽  
Human Plasma ◽  
Ammonium Sulfate ◽  
Inverse Relationship ◽  
Ph Value ◽  
Distilled Water ◽  
Human Fibrinogen ◽  
Ph Values ◽  
Ph Dependent ◽  
Limited Digestion

SummaryAddition of thrombin to plasma obtained from dogs injected with plasmin clotted more fibrinogen when the plasma was diluted with saline than when it was diluted with distilled water. In contrast, more fibrin was formed in dilutions with distilled water when thrombin was added to intact plasma obtained prior to the injection of plasmin.The same phenomenon was observed with purified human fibrinogen submitted to limited digestion with plasmin and was found to be pH dependent. When the pH was greater than 7.3 more fibrin was formed if the fibrinogen was diluted with saline than if it was diluted with distilled water. The opposite was observed at pH values lower than 7.2.Similar results were obtained with the fraction of partially lysed human fibrinogen which precipitates at 25% saturation with ammonium sulfate. The same fraction, however, obtained from partially digested bovine fibrinogen did not react exactly the same way. In dilutions with distilled water there was an inverse relationship between the pH value and the amount of protein which clotted; but the reverse did not apply to the same extent in dilutions with saline.At variance to the above observations the clottability of purified intact fibrinogen was not significantly altered by changes in pH or in ionic strength.The clottability of partially lysed human plasma could be reversed (more fibrin in distilled water than in saline) after exhaustive dialysis against oxalated (pH 7.0) but not against citrated (pH 7.8) saline indicating that the change in clottability was due to a change in pH.

Why is the hydrolytic activity of acetylcholinesterase pH dependent? Kinetic study of acetylcholine and acetylthiocholine hydrolysis catalyzed by acetylcholinesterase from electric eel

2018 ◽  
Vol 73 (9-10) ◽  
pp. 345-351 ◽  
Author(s):  
Alena Komersová ◽  
Markéta Kovářová ◽  
Karel Komers ◽  
Václav Lochař ◽  
Alexander Čegan
Keyword(s):  
Catalytic Activity ◽  
Ionic Strength ◽  
Ph Value ◽  
Hydrolytic Activity ◽  
Initial Substrate ◽  
Electric Eel ◽  
Value Range ◽  
Ph Dependent ◽  
Ph Range ◽  
Initial Substrate Concentration

AbstractThe dependence of the activity of acetylcholinesterase from electric eel at a pH value range of 4.8–9.8 (phosphate buffer), regarding acetylcholine and acetylthiocholine hydrolysis, was determined at 25 °C, ionic strength of 0.11 M, and initial substrate concentration of 4 mM. At a pH range of 4.8–9.8, the dependencesA(pH) form a sigmoid increasing curve with the maximum catalytic activity at a pH range 8–9.5. For acetylcholine hydrolysis, the kinetic reason for such an increase inAconsists mainly of an increase in the rate constantk2(Michaelis-Menten) model with increasing pH of the reaction mixture. For acetylthiocholine hydrolysis, the kinetic explication of the determined dependenceA(pH) is more complicated.

pH-Dependent Assembly of Reduced Polyoxomolybdenum Phosphates Modified by MnII

2011 ◽  
Vol 64 (11) ◽  
pp. 1501 ◽  
Author(s):  
Jing Lu ◽  
Hou-Ting Liu ◽  
Hao Song ◽  
Su-Na Wang ◽  
Da-Qi Wang ◽  
...  
Keyword(s):  
Electron Density ◽  
Hydrothermal Reaction ◽  
Ph Value ◽  
Antiferromagnetic Coupling ◽  
Ph Values ◽  
Coordination Ability ◽  
Ph Dependent

Three reduced polyoxomolybdenum(v) phosphates modified by MnII: (Hen)(H2en){Mn(H2O)[Mn0.5Mo6(HPO4)3(PO4)(OH)3O12]}·2H2O (1) (en = ethylenediamine), (en)(Hen)4{Mn(H2O)[MnMo12(H2PO4)3(HPO4)4(PO4)(OH)6O24]}·3.5H2O (2), and [H7(en)Mn2.5P4Mo6O31(H2O)3]·2.5H2O (3) were synthesized through the hydrothermal reaction at different pH values. Compound 1 exhibits a 3-D framework; each basic [Mn(P4Mo6O31)2] unit coordinates with eight MnII ions. Compound 2 contains two kinds of [Mn(P4Mo6O31)2] basic units, which are linked by MnII ions to form a 2-D network. For compound 3, each basic [Mn(P4Mo6O31)2] unit is modified by 12 MnII ions and exhibits a 3-D framework. It was established that the pH of the reaction and the amount of ethanediamine play very important roles in the assembly of polyoxometalate-based compounds. The pH value determines the electron density of polyoxometalate and the degree of en protonation, which affect the coordination ability of polyoxometalates and result in different structures. Compounds 1–3 display weak antiferromagnetic coupling.

scholarly journals Zinc adsorption in highly weathered soils

2008 ◽  
Vol 43 (1) ◽  
pp. 131-139 ◽  
Author(s):  
José Carlos Casagrande ◽  
Marcio Roberto Soares ◽  
Ernesto Rinaldi Mouta
Keyword(s):  
Ionic Strength ◽  
Ph Value ◽  
Batch Adsorption ◽  
Adsorption Mechanisms ◽  
Ionic Strength Effect ◽  
Ph Values ◽  
Effects Of Ph ◽  
Ph Range ◽  
Highly Weathered Soils ◽  
Zinc Adsorption

The objective of this work was to assess the effects of pH and ionic strength upon zinc adsorption, in three highly weathered variable charge soils. Adsorption isotherms were elaborated from batch adsorption experiments, with increasing Zn concentrations (0-80 mg L-1), and adsorption envelopes were constructed through soil samples reactions with 0.01, 0.1 and 1 mol L-1 Ca(NO3)2 solutions containing 5 mg L-1 of Zn, with an increasing pH value from 3 to 8. Driving force of reaction was quantified by Gibbs free energy and separation factor. Isotherms were C-, H- and L-type and experimental results were fitted to nonlinear Langmuir model. Maximum adsorption ranged from 59-810 mg kg-1, and Zn affinity was greater in subsoil (0.13-0.81 L kg-1) than in the topsoil samples (0.01-0.34 L kg-1). Zinc adsorption was favorable and spontaneous, and showed sharply increase (20-90%) in the 4-6 pH range. No effect of ionic strength was observed at pH values below 5, because specific adsorption mechanisms predominated in the 3-5 pH range. Above pH 5, and in subsoil samples, Zn was adsorbed by electrostatic mechanisms, since ionic strength effect was observed. Despite depth and ionic strength effects, Zn adsorption depends mainly on the pH.

scholarly journals Evaluation of calcium release and pH value of light-cured cavity liners for pulp-capping materials

2018 ◽  
Vol 47 (4) ◽  
pp. 205-209
Author(s):  
Kamila de Figueiredo PEREIRA ◽  
Rosymere Freitas de Sousa CRUVINEL ◽  
Andrea Abi Rached DANTAS ◽  
Milton Carlos KUGA
Keyword(s):  
Calcium Hydroxide ◽  
Calcium Release ◽  
Ph Value ◽  
Distilled Water ◽  
High Solubility ◽  
Pulp Capping ◽  
Tukey Test ◽  
Ph Values ◽  
Low Strength

Abstract Introduction Cavity liners based calcium hydroxide present low strength and high solubility that is consider a disadvantage. In order to enhance these properties it was developed a light-cured cavity liner based calcium hydroxide containing resin. Objective The purpose of this study was to evaluate the pH and calcium release of light-cured cavity liners. Material and method There were prepared specimens (n=10) with the Ultra-Blend ® plus, Biocal® (light cured cements) and Hydro C® (control). The samples were stored in 10 mL of distilled water and maintained at 37 °C. After 24 hours, 7, and 14 days, there were analyzed pH and the release of calcium levels. The data were statistically analyzed by ANOVA and Tukey test (α = 0.05). Result The results of pH showed Hydro C > Ultra-Blend plus > Biocal. Biocal presented worst calcium release. Conclusion Light-cured materials present lower calcium release and alteration in pH values.

scholarly journals Effect of calcium chloride on the pH values of several formulations of calcium hydroxide mixed with chlorhexidine digluconate

2013 ◽  
Vol 1 (4) ◽  
pp. 344
Author(s):  
Hemanoely Marins-de-Azevedo ◽  
Rodrigo Vargas Conti Montenario ◽  
Mariana Pires Crespo ◽  
Milton Carlos Kuga ◽  
Camila Almeida Nascimento
Keyword(s):  
Calcium Hydroxide ◽  
Calcium Chloride ◽  
Ph Value ◽  
Distilled Water ◽  
Chlorhexidine Digluconate ◽  
Ph Values ◽  
Term Analysis

This study evaluated the effect of the addition of 5% calcium chlorite (CaCl2) on pH values in calcium hydroxide pastes (CH), with or without 2% chlorhexidine digluconate (CHX) used as vehicle, in several periods analysis. Polyethylene tubes were filled with CH mixed with water (G1), 2% CHX solution (G2) or gel (G3), or CHX solution  or gel with 5% CaCl2 (G4 and G5, respectively). All tubes were individually immersed in distilled water. After 12, 24 hours, 7, 14 and 28 days, pH value was evaluated directly in water which the tubes were stored. Data were submitted to ANOVA and Tukey tests (α=0.05). In 24 hs and 14 days, pH values were similar to all groups. In 12 hs, the G1 presented lower pH value than other groups except to G4 (p < 0.05), and G4 presented lower pH value than G5 (p < 0.05). In 7 days, G1 presented lower pH value than G4 and G5 (p < 0.05). In 28 days, G1 and G5 presented lower pH values than G2 and G4 (p < 0.05) and among other groups there are no statistical differences (p > 0.05). The pH values increased in long-term analysis to all CH pastes. The association of 5% calcium chloride with 2% CHX solution as vehicle of CH paste provided a pH value increase in relation to CH mixed with distilled water. The CHX gel interfered negatively on pH value in comparison to CHX solution when mixed with CaCl2.

Ionic-strength- and pH-dependent conformational states of human plasma fibronectin

Biochemistry ◽  
1991 ◽  
Vol 30 (17) ◽  
pp. 4298-4306 ◽  
Author(s):  
Michael J. Benecky ◽  
Richard W. Wine ◽  
Carl G. Kolvenbach ◽  
Michael W. Mosesson
Keyword(s):  
Ionic Strength ◽  
Human Plasma ◽  
Plasma Fibronectin ◽  
Conformational States ◽  
Ph Dependent

Influence of Ionic Strength and pH-value on the Silicon Dioxide Polishing Behaviour of Slurries Based on Pure Silica Suspensions

2010 ◽  
Vol 1249 ◽  
Author(s):  
Ulrich Kuenzelmann ◽  
Kathrin Estel ◽  
Johann W Bartha ◽  
Erwin-Peter Meyer ◽  
Herbert Barthel
Keyword(s):  
Ionic Strength ◽  
Fumed Silica ◽  
Ph Value ◽  
Acidic Ph ◽  
Experimental Conditions ◽  
Ph Values ◽  
Pure Silica ◽  
Silica Sols ◽  
Ph Range ◽  
Silica Suspensions

AbstractIn this study, the effect of the addition of electrolytes in a given ionic strength to various high-purity silica suspensions was investigated by measurement of the removal rates (RR's) in CMP processes on oxide layers under the same experimental conditions. As so-called slurries the following suspensions were used: i) silica sols produced by the Stöber process, ii) conventional silica sols based on alkali silicate as well as iii) suspensions of fumed silica, with the same SiO2 concentration in each suspension. Ionic strength of the added electrolyte was adjusted to e.g. 0.065 mol/l, with the electrolytes being HCl, NH4Cl, KOH, or binary mixtures of these substances.These investigations revealed significant differences of the polishing behaviour between the different types of silica dispersions as slurries. While for the Stöber sols investigated, the RR's are highest in the acidic range and almost negligible in the alkaline pH range, fumed silica suspensions show an entirely different behaviour: RR is very low for acidic pH-values, and increases with the alkalinity of the slurry. In contrast to these observations, the RR's of slurries based on conventional silica sols are highest around the neutral point, and show a decrease for both more alkaline and acidic pH-values. In comparison to the other two types of material, these suspensions have a high amount of electrolyte background, originating from their manufacturing process.A model is developed to explain these results in a comprehensive manner. It involves effects of the electrolyte type and the ionic strengths as well as influences of the particle size.

Temperature Effects and pH Value on Free Swell Behaviors of Bentonite Solutions

2014 ◽  
Vol 983 ◽  
pp. 44-51
Author(s):  
Han Yong Jeon
Keyword(s):  
Ph Value ◽  
Distilled Water ◽  
Sodium Bentonite ◽  
Ph Values ◽  
Volume State ◽  
Physical Form ◽  
Different Temperatures ◽  
Free Swell ◽  
Powder Type ◽  
Swelling Behaviors

Swelling behaviors of powder and granular type sodium bentonites in permeate solutions such as NaCl, KCl, MgCl2, CaCl2, distilled water and in HCl and NaOH (with different pH values) under different temperatures were investigated. Swelling behaviors of these bentonites were dependent on strength, reactivity power and physical form of ion, and temperature and pH value of permeate solution. +1 ion solution showed higher swell volumes than +2 ion solution. Distilled water showed highest swell volumes among these tested solutions. Powder type sodium bentonite showed higher swells volume than granular type bentonite. Higher temperatures brought quickly the bentonite to a stable swell volume state. The pH value also affected on swelling volumes of bentonite as lower pH values (pH<3) increased and higher pH values (11<pH<12) decreased the swell volume of powder and granular type sodium bentonite.

Effect of Fibrinolysin on the Coagulability of Fibrinogen

1962 ◽  
Vol 07 (03) ◽  
pp. 421-431
Author(s):  
D. C Triantaphyllopoulos ◽  
T. L Greene ◽  
E Triantaphyllopoulos
Keyword(s):  
Human Plasma ◽  
Calcium Chloride ◽  
Physiological Saline ◽  
Caproic Acid ◽  
Distilled Water ◽  
Human Origin ◽  
Time Intervals ◽  
Human Fibrinogen ◽  
Enzyme Action ◽  
Fibrinogen Content

SummaryStreptokinase or glycerol activated human fibrinolysin was added to human plasma and the enzyme action was stopped by the addition of epsilon amino-caproic acid at different time intervals. The clottable fibrinogen content of the mixtures was determined by diluting the plasma with either physiological saline or distilled water, both containing thrombin or thrombin plus calcium chloride. It was found that before the addition of fibrinolysin the values in distilled water containing calcium chloride were higher than the respective values in plain saline or in saline containing calcium chloride. The drop in clottable fibrinogen after the addition of fibrinolysin was more pronounced when the determinations were performed in plain distilled water. Thus, a crossover between the values obtained in plain distilled water and those in saline gradually occurred, the values in distilled water without calcium chloride becoming the lowest. This is at variance with the results obtained in the presence of added AFIF or fibrinolysed fibrinogen where the values in distilled water were always higher than the ones obtained in saline both in the presence and in the absence of calcium chloride. Since the reversal of coagulability of fibrinogen in physiological saline versus distilled water was reproduced only when we mixed partially lysed human fibrinogen with completely lysed human plasma, the conclusion was drawn that three prerequisites are necessary for this phenomenon to occur: a) the fibrinogen must have been acted upon by fibrinolysin; b) the fibrinogen must be of human origin; c) a substance produced by the action of fibrinolysin on a plasmatic factor other than fibrinogen or, possibly, an intact plasmatic factor, must be present.

Donnan Equilibria in Polymeric Micellar Systems with Weak Polyelectrolyte Shells: The Lowering of the pH Value

1997 ◽  
Vol 62 (11) ◽  
pp. 1730-1736 ◽  
Author(s):  
Petr Munk ◽  
Zdeněk Tuzar ◽  
Karel Procházka
Keyword(s):  
Ionic Strength ◽  
Block Copolymer ◽  
Ph Value ◽  
Electrolyte Solutions ◽  
Hydrogen Ions ◽  
Micellar Systems ◽  
Weak Electrolytes ◽  
Block Copolymer Micelles ◽  
Copolymer Micelles ◽  
Polyelectrolyte Solutions

When two electrolyte solutions are separated and only some of the ions can cross the boundary, the concentrations of these ions are different on both sides of the boundary. This is the well-known Donnan effect. When weak electrolytes are involved, the imbalance includes also hydrogen ions: there is a difference of pH across the boundary and the dissociation of nondiffusible weak electrolytes is suppressed. The effect is very pronounced when the concentration of the weak electrolyte is high and ionic strength is low. The significance of this phenomenon is discussed for polyelectrolyte solutions, and particularly for block copolymer micelles with weak polyelectrolyte shells. The effect is quite dramatic in the latter case.

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