Separation of Free and Protein-Bound Ligand Molecules by Means of Protein-Coated Charcoal

1974 ◽  
Vol 20 (9) ◽  
pp. 1146-1149 ◽  
Author(s):  
Esper Mortensen
Keyword(s):  
Separation Method ◽  
Mass Action ◽  
Careful Evaluation ◽  
Experimental Conditions ◽  
Model Experiments

Abstract Separation of free and protein-bound ligand molecules by means of protein-coated charcoal has been studied in model experiments. The results can be described by applying the simple laws of mass action and dilution, and indicate the need for a careful evaluation of the charcoal that is being used and a testing against an ideal separation method whenever experimental conditions are determined or changed.

Simulation of the Denitrification Process of Waste Water with a Biochemical Systems Model: A Non-Conventional Approach

2014 ◽  
Vol 12 (2) ◽  
pp. 683-693
Author(s):  
Nouceiba Adouani ◽  
Lionel Limousy ◽  
Thomas Lendormi ◽  
Eberhard O. Voit ◽  
Olivier Sire
Keyword(s):  
Waste Water ◽  
Nitrate Reduction ◽  
International Association ◽  
Mass Action ◽  
Experimental Conditions ◽  
Systems Model ◽  
Theoretical Approaches ◽  
Biochemical Systems ◽  
Nitrate And Nitrite ◽  
Denitrification Process

Abstract Matching experimental and theoretical approaches have often been fruitful in the investigation of complex biological processes. Here we develop a novel non-conventional model for the denitrification of waste water. Earlier models of the denitrification process were compiled by the International Association on Water Quality group. The Activated Sludge Models 1–3, which are the most frequently used all over the world, are presently not adapted towards the integration of both nitrous and nitric oxide emissions during the denitrification process. In the present work, a Generalized Mass Action model, based on Biochemical Systems Theory, was designed to simulate the nitrate reduction observed in specific experimental conditions. The model was implemented and analysed with the software package PLAS. Data from a representative experiment were chosen (T=10°C, pH=7, C/N=3, with acetate as carbon source) to simulate greenhouse NO and N2O gas emissions, in order to test hypotheses about the corresponding bacterial metabolic pathways. The results show that the reduction of nitrate and nitrite is kinetically limiting and that nitrate reduction is limited by diffusion and support that distinct microbial subpopulations are involved in the denitrification pathway, which has consequences for NO emissions.

scholarly journals On the estimation errors of KM and V from time-course experiments using the Michaelis–Menten equation

2016 ◽  
Author(s):  
Wylie Stroberg ◽  
Santiago Schnell
Keyword(s):  
Time Course ◽  
Enzyme Concentration ◽  
Mass Action ◽  
Accurate Estimation ◽  
Estimation Errors ◽  
Experimental Conditions ◽  
Progress Curve ◽  
Steady State Kinetics ◽  
Initial Substrate ◽  
Order Of Magnitude

AbstractThe conditions under which the Michaelis–Menten equation accurately captures the steady-state kinetics of a simple enzyme-catalyzed reaction is contrasted with the conditions under which the same equation can be used to estimate parameters, KM and V, from progress curve data. Validity of the underlying assumptions leading to the Michaelis–Menten equation are shown to be necessary, but not sufficient to guarantee accurate estimation of KM and V. Detailed error analysis and numerical “experiments” show the required experimental conditions for the independent estimation of both KM and V from progress curves. A timescale, tQ, measuring the portion of the time course over which the progress curve exhibits substantial curvature provides a novel criterion for accurate estimation of KM and V from a progress curve experiment. It is found that, if the initial substrate concentration is of the same order of magnitude as KM, the estimated values of the KM and V will correspond to their true values calculated from the microscopic rate constants of the corresponding mass-action system, only so long as the initial enzyme concentration is less than KM.

scholarly journals The Removal of Silicate(IV) by Adsorption onto Hydrocalumite from the Sodium Hydroxide Leaching Solution of Black Dross

Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 612 ◽  
Author(s):  
Thi Thuy Nhi Nguyen ◽  
Man Seung Lee
Keyword(s):  
Reaction Time ◽  
Selective Adsorption ◽  
Freundlich Isotherm ◽  
Complete Removal ◽  
Mass Action ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Experimental Conditions ◽  
Alkaline Leaching ◽  
Leaching Solution

Alkaline leaching of mechanically activated black dross resulted in an aluminate(III) solution with a small amount of silicate(IV). To obtain pure aluminate(III) solution, the removal of silicate(IV) from the alkaline leaching solution was investigated by adsorption with hydrocalumite (Ca2Al(OH)6Cl·2H2O). The hydrocalumite was synthesized by the coprecipitation method. The characterization of the synthesized hydrocalumite was analyzed via X-ray diffraction (XRD), scanning electron microscopy (SEM) images and Fourier-transform infrared spectroscopy (FTIR). In our experimental conditions, silicate(IV) was selectively adsorbed onto hydrocalumite over aluminate(III). The reaction time greatly affected the removal percentage of aluminate(III) owing to mass action effect. When the reaction time was longer than 2 h, no aluminate(III) was adsorbed onto hydrocalumite and thus it was possible to selectively remove silicate(IV). When the dosage of hydrocalumite was in excess, the removal percentage of silicate(IV) was rather reduced. Complete removal of silicate(IV) from the solution was accomplished in the reaction temperature between 50 and 70 °C. By selective adsorption of silicate(IV) from the solution at the optimum condition (30 g/L hydrocalumite, 50 °C, 400 rpm, and 2 h), an aluminate(III) solution with purity higher than 99.9% was obtained. The adsorption of silicate(IV) onto hydrocalumite followed the Freundlich isotherm.

Chiral liquid membrane for enantioselective separation of racemic ibuprofen by l-tartaric acid derivatives

RSC Advances ◽  
2015 ◽  
Vol 5 (52) ◽  
pp. 41729-41735 ◽  
Author(s):  
Fan Zhang ◽  
Lichao He ◽  
Wei Sun ◽  
Yongqi Cheng ◽  
Junteng Liu ◽  
...  
Keyword(s):  
Tartaric Acid ◽  
Separation Factor ◽  
Liquid Membrane ◽  
Separation Method ◽  
Enantioselective Separation ◽  
Experimental Conditions ◽  
Tartaric Acid Derivatives ◽  
Racemic Ibuprofen

Use of a chiral liquid membrane is an attractive separation method for racemic ibuprofen, and the separation factor could be up to 1.38 under optimal experimental conditions.

Control of glycogenosis in rainbow trout muscle during exercise

1988 ◽  
Vol 66 (2) ◽  
pp. 345-351 ◽  
Author(s):  
W. S. Parkhouse ◽  
G. P. Dobson ◽  
P. W. Hochachka
Keyword(s):  
Rainbow Trout ◽  
Thermodynamic Equilibrium ◽  
White Muscle ◽  
Glycogen Content ◽  
Phosphoglycerate Kinase ◽  
Mass Action ◽  
Glycolytic Flux ◽  
Experimental Conditions ◽  
Potential Control ◽  
Red Muscle

The purpose of this study was to measure and compare the in vivo levels of glycolytic pathway intermediates during high-intensity, progressive exercise in rainbow trout red and white muscle. The mass action ratios of those reactions catalyzed by the enzymes hexokinase, phosphofructokinase, and pyruvate kinase appear to be displaced far from thermodynamic equilibrium (greater than log 2) under all experimental conditions in both tissue types. Furthermore, the near-equilibrium glyceral-dehyde 3-phosphate dehydrogenase – phosphoglycerate kinase complex deviated from thermodynamic equilibrium during the exhaustive swim for white muscle and for all exercise intensities in red muscle. The mass action ratio of the combined glyceraldehyde 3-phosphate dehydrogenase – phosphoglycerate kinase/lactate dehydrogenase demonstrated displacements from thermodynamic equilibrium similar to those of the glyceraldehyde 3-phosphate dehydrogenase complex. Potential control sites were identified as phosphorylase for white muscle and hexokinase and glyceraldehyde 3-phosphate dehydrogenase – phosphoglycerate kinase for red muscle. No alterations in potential control sites were found in white muscle with changing flux rates (sustained and burst swims) provided sufficient glycogen was available as precursor. Phosphofructokinase and glyceraldehyde 3-phosphate dehydrogenase only demonstrated potential control in this tissue when glycogen content and flux rates were low (exhaustive swim). These changes coincided with substrate depletion to low levels and large declines in the ATP/ADPf ratio. Therefore, it would appear that glycogen content is the primary factor regulating glycolytic flux and control sites via alterations in adenylate levels.

Electrolytic Isolation of Twin-Type Shock Deformation Structures

1967 ◽  
Vol 25 ◽  
pp. 318-319
Author(s):  
F. I. Grace ◽  
L. E. Murr
Keyword(s):  
Grain Boundaries ◽  
Thin Foil ◽  
Electrolyte Composition ◽  
Experimental Conditions ◽  
Average Current Density ◽  
Electron Transmission ◽  
Deformation Structures ◽  
The Matrix ◽  
Average Current ◽  
Specimen Edge

During the course of electron transmission investigations of the deformation structures associated with shock-loaded thin foil specimens of 70/30 brass, it was observed that in a number of instances preferential etching occurred along grain boundaries; and that the degree of etching appeared to depend upon the various experimental conditions prevailing during electropolishing. These included the electrolyte composition, the average current density, and the temperature in the vicinity of the specimen. In the specific case of 70/30 brass shock-loaded at pressures in the range 200-400 kilobars, the predominant mode of deformation was observed to be twin-type faults which in several cases exhibited preferential etching similar to that observed along grain boundaries. A novel feature of this particular phenomenon was that in certain cases, especially for twins located in the vicinity of the specimen edge, the etching or preferential electropolishing literally isolated these structures from the matrix.

Site of Lysosome Production During Hepatic Injury

1969 ◽  
Vol 27 ◽  
pp. 348-349
Author(s):  
Nalin J. Unakar
Keyword(s):  
Electron Microscopy ◽  
Golgi Apparatus ◽  
Mouse Liver ◽  
Hepatic Injury ◽  
Close Approximation ◽  
Experimental Conditions ◽  
Toxic Injury

The increased number of lysosomes as well as the close approximation of lysosomes to the Golgi apparatus in tissue under variety of experimental conditions is commonly observed. These observations suggest Golgi involvement in lysosomal production. The role of the Golgi apparatus in the production of lysosomes in mouse liver was studied by electron microscopy of liver following toxic injury by CCI4.

Optimizing conditions for x-ray microchemical analysis in analytical electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 548-549 ◽  
Author(s):  
N. J. Zaluzec
Keyword(s):  
Solid Angle ◽  
Analytical Electron Microscopy ◽  
Incident Beam ◽  
Thin Foil ◽  
Experimental Conditions ◽  
X Ray ◽  
Microchemical Analysis ◽  
Analytical Electron ◽  
Image Position ◽  
Incident Beam Energy

The ultimate sensitivity of microchemical analysis using x-ray emission rests in selecting those experimental conditions which will maximize the measured peak-to-background (P/B) ratio. This paper presents the results of calculations aimed at determining the influence of incident beam energy, detector/specimen geometry and specimen composition on the P/B ratio for ideally thin samples (i.e., the effects of scattering and absorption are considered negligible). As such it is assumed that the complications resulting from system peaks, bremsstrahlung fluorescence, electron tails and specimen contamination have been eliminated and that one needs only to consider the physics of the generation/emission process.The number of characteristic x-ray photons (Ip) emitted from a thin foil of thickness dt into the solid angle dΩ is given by the well-known equation

SEM analysis of the change in the reaction rates with deposit structures in the copper-iron cementation system

1978 ◽  
Vol 36 (1) ◽  
pp. 456-457
Author(s):  
V. Annamalai ◽  
L.E. Murr
Keyword(s):  
Structural Characteristics ◽  
Secondary Electron Emission ◽  
Copper Deposit ◽  
Reaction Rates ◽  
Sem Analysis ◽  
Experimental Conditions ◽  
Major Drawback ◽  
Emission Mode ◽  
Scrap Iron ◽  
Image Position

Economical recovery of copper metal from leach liquors has been carried out by the simple process of cementing copper onto a suitable substrate metal, such as scrap-iron, since the 16th century. The process has, however, a major drawback of consuming more iron than stoichiometrically needed by the reaction.Therefore, many research groups started looking into the process more closely. Though it is accepted that the structural characteristics of the resultant copper deposit cause changes in reaction rates for various experimental conditions, not many systems have been systematically investigated. This paper examines the deposit structures and the kinetic data, and explains the correlations between them.A simple cementation cell along with rotating discs of pure iron (99.9%) were employed in this study to obtain the kinetic results The resultant copper deposits were studied in a Hitachi Perkin-Elmer HHS-2R scanning electron microscope operated at 25kV in the secondary electron emission mode.

Relative Intensities in ED Patterns From Thin Gold Films

1972 ◽  
Vol 30 ◽  
pp. 636-637
Author(s):  
R. H. Morriss ◽  
J. D. C. Peng ◽  
C. D. Melvin
Keyword(s):  
Theoretical Calculations ◽  
Diffraction Theory ◽  
Gold Films ◽  
Reasonable Accuracy ◽  
Experimental Conditions ◽  
Crystal Perfection ◽  
Heavy Atoms ◽  
Fine Focus ◽  
Convergent Beam ◽  
Beam Diffraction

Although dynamical diffraction theory was modified for electrons by Bethe in 1928, relatively few calculations have been carried out because of computational difficulties. Even fewer attempts have been made to correlate experimental data with theoretical calculations. The experimental conditions are indeed stringent - not only is a knowledge of crystal perfection, morphology, and orientation necessary, but other factors such as specimen contamination are important and must be carefully controlled. The experimental method of fine-focus convergent-beam electron diffraction has been successfully applied by Goodman and Lehmpfuhl to single crystals of MgO containing light atoms and more recently by Lynch to single crystalline (111) gold films which contain heavy atoms. In both experiments intensity distributions were calculated using the multislice method of n-beam diffraction theory. In order to obtain reasonable accuracy Lynch found it necessary to include 139 beams in the calculations for gold with all but 43 corresponding to beams out of the [111] zone.

Sign in / Sign up

Export Citation Format

Share Document