The kinetic parameters and the electrochemical mechanism for the polarographic reduction of nitromethane

1960 ◽  
Vol 25 (12) ◽  
pp. 3202-3212 ◽  
Author(s):  
M. Suzuki ◽  
P. J. Elving
Keyword(s):  
Kinetic Parameters ◽  
Polarographic Reduction ◽  
Electrochemical Mechanism

Polarographic reduction of phenolphthalein, cresolphthalein, thymolphthalein, and α-naphtholphthalein in aqueous and nonaqueous ethanolic solutions

1979 ◽  
Vol 57 (11) ◽  
pp. 1294-1298 ◽  
Author(s):  
Mohamed M. Ghoneim ◽  
Mohamed A. A. Ashy
Keyword(s):  
Kinetic Parameters ◽  
Aqueous Medium ◽  
Electrode Reaction ◽  
Polarographic Reduction ◽  
The Waves

The polarographic reduction of phenolphthalein, cresolphthalein, thymolphthalein, and α-naphtholphthalein has been studied in ethanolic Britton–Robinson buffer series (pH 2–12), non-aqueous ethanolic medium, and water–ethanol mixtures. The compounds are reduced through a single 2e− wave in non-aqueous medium and aqueous buffered solutions of pH < 9 or 1e− steps for pH > 9. The nature of the waves, mechanism of the electrode reaction, and kinetic parameters has been considered.

Polarographic Reduction of Zinc and Thorium in Furfuryl Mercaptan Media

1973 ◽  
Vol 28 (7-8) ◽  
pp. 429-432
Author(s):  
R. S. Sαxena ◽  
S. S. Sheelwant
Keyword(s):  
Transfer Coefficient ◽  
Kinetic Parameters ◽  
Rate Constant ◽  
Polarographic Reduction ◽  
Electrode Reactions ◽  
Diffusion Controlled ◽  
And Diffusion

The reduction of Zn and Th in furfuryl mercaptan has been found to be irreversible and diffusion-controlled in 50% ethanolic media and 0.1 M NaClO4. The values of kinetic parameters - transfer coefficient (α), formal rate constant (K°f,h) - for the electrode reactions were determined by KOUTECKY’S method as extended by MEITES and ISRAEL. The values of ΔH, ΔG and ΔS have also been reported.

MEASUREMENT OF STEROID BINDING PROTEINS

1970 ◽  
Vol 65 (1_Suppl) ◽  
pp. S104-S121 ◽  
Author(s):  
E. E. Baulieu ◽  
J. P. Raynaud ◽  
E. Milgrom
Keyword(s):  
Kinetic Parameters ◽  
Binding Proteins ◽  
Binding Specificity ◽  
Binding Parameters ◽  
Target Organs ◽  
Biological Mixtures ◽  
Steroid Binding Proteins ◽  
Steroid Binding ◽  
Steroid Binding Protein

ABSTRACT A brief review of the characteristics of steroid binding proteins found in the plasma and in some target organs is presented, followed by some general remarks on binding »specificity« and binding parameters. Useful techniques for measuring binding parameters at equilibrium are reported, both those which keep the equilibrium intact and those which implicate its disruption. A concept is developed according to which the determination of a specific steroid binding protein is based on the »differential dissociation« of the several steroid binding complexes present in most biological mixtures. Methods which allow determination of the kinetic parameters of the binding systems are also presented. Various representations of the binding and therefore different modes of graphic representation and calculation are discussed, including the recent »proportion graph« method.

THE INFLUENCE OF ETHANOL ON THE CONVERSION OF PREGNENOLONE TO PROGESTERONE BY HUMAN PLACENTAL MICROSOMES

1974 ◽  
Vol 76 (1) ◽  
pp. 178-188 ◽  
Author(s):  
H. Lübbert ◽  
K. Pollow ◽  
R. Wagner ◽  
J. Hammerstein
Keyword(s):  
Kinetic Parameters ◽  
Enzyme Preparation ◽  
Ethanol Concentration ◽  
Hydroxysteroid Dehydrogenase ◽  
Product Formation ◽  
Linear Increase ◽  
Maximal Velocity ◽  
Microsomal Enzyme ◽  
Temperature Optima ◽  
Substrate Concentrations

ABSTRACT The effects of ethanol on kinetic parameters of placental Δ5-3β-hydroxysteroid dehydrogenase were studied. In the presence of high pregnenolone concentrations (50 μm, [S] > Km) the microsomal enzyme preparation exhibited an almost linear increase in activity as the ethanol concentration in the medium was raised from 2.5 to 15 % (v/v). At lower substrate concentrations ([S] << Km) ethanol caused inhibition. Other effects of ethanol were: linearity of product formation with time was prolonged; the maximal velocity was markedly increased; the Km for pregnenolone slightly decreased with increasing ethanol concentrations (2.5 to 10 %, v/v) whereas the Km for NAD remained the same. The pH and temperature optima of the reaction were unaffected by ethanol. Other organic solvents caused similar effects.

Study on the influence on the formation of highly ordered porous anodic aluminia membrane

2017 ◽  
Author(s):  
O Pong-Sik ◽  
Ryang Se-Hun ◽  
Sin Gum-Chol ◽  
Hwang Guk-Nam ◽  
yongson hong
Keyword(s):  
Pore Diameter ◽  
Electrolyte Concentration ◽  
Aao Template ◽  
Alumina Template ◽  
Wide Range ◽  
Electrochemical Mechanism ◽  
Porous Anodic Alumina Template ◽  
Ordered Porous ◽  
Anodic Alumina Template ◽  
Scanning Electron

We have studied porous anodic alumina template through the second anodic oxidation of preparation. Observing the morphology of nanoscale AAO template using scanning electron microscope (SEM), the results indicate that the pores are orderly paralleled arranged with uniform pore diameter, perpendicular to the template surface. A detailed study of the influence of different oxidation conditions, such as different type of electrolyte, concentration, voltage and temperature on the template of alumina and its electrochemical mechanism were performed. By changing the oxidation voltage, electrolyte type, concentration, pore diameter and template thickness can be altered in a wide range such that we can obtain the desired aspect ratio. <br>

Evaluation of Kinetic Parameters at the Transport of Indole-3-acetic Acid Through Bulk Liquid Membranes

2017 ◽  
Vol 68 (5) ◽  
pp. 903-907
Author(s):  
Ecaterina Anca Serban ◽  
Ioana Diaconu ◽  
Elena Ruse ◽  
Georgiana Ileana Badea ◽  
Adriana Cuciureanu ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Kinetic Parameters ◽  
Trioctylphosphine Oxide ◽  
Bulk Liquid ◽  
Transport Parameters ◽  
Kinetics Parameters ◽  
First Order ◽  
Phase Concentration ◽  
Feed Phase ◽  
Indole 3 Acetic Acid

Indole-3-acetic acid is a growth phytohormone considered the most important representative of auxin class. This paper presents the assessment of some kinetic parameters in the process of transport of indole-3-acetic acid taking into consideration the kinetic model of consecutive irreversible first order reactions. It was pursued the influence upon the process of parameters such as: feed phase concentration, stripping phase concentration in the presence of two type carriers: tributyl phosphate (TBP) and trioctylphosphine oxide (TOPO). Depending on these transport parameters were calculated kinetics parameters such as: pseudo-first-order apparent membrane entrance and exit rate constants, the maximum flux at the entrance and exit out of the membrane. The highest values of the transport flux is obtained in the presence of carrier trioctylphosphine oxide (TOPO) at the concentration in the feed phase of 10-4 mol/L indole-3-acetic acid and a concentration of 10--2mol/L NaOH in the stripping phase.

A Technique to Determine Unsteady-State Inhibition Kinetics in the Activated Sludge Process

1989 ◽  
Vol 21 (6-7) ◽  
pp. 593-602 ◽  
Author(s):  
Andrew T. Watkin ◽  
W. Wesley Eckenfelder
Keyword(s):  
Activated Sludge ◽  
Kinetic Parameters ◽  
Curve Fitting ◽  
Glucose Utilization ◽  
Batch Reactor ◽  
Synthetic Data ◽  
Utilization Rate ◽  
Fitting Algorithm ◽  
Test Reactor ◽  
Two Parameter

A technique for rapidly determining Monod and inhibition kinetic parameters in activated sludge is evaluated. The method studied is known as the fed-batch reactor technique and requires approximately three hours to complete. The technique allows for a gradual build-up of substrate in the test reactor by introducing the substrate at a feed rate greater than the maximum substrate utilization rate. Both inhibitory and non-inhibitory substrate responses are modeled using a nonlinear numerical curve-fitting technique. The responses of both glucose and 2,4-dichlorophenol (DCP) are studied using activated sludges with various acclimation histories. Statistically different inhibition constants, KI, for DCP inhibition of glucose utilization were found for the various sludges studied. The curve-fitting algorithm was verified in its ability to accurately retrieve two kinetic parameters from synthetic data generated by superimposing normally distributed random error onto the two parameter numerical solution generated by the algorithm.

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