scholarly journals Purification of glycolytic enzymes by using affinity-elution chromatography

1977 ◽  
Vol 161 (2) ◽  
pp. 253-263 ◽  
Author(s):  
R K Scopes
Keyword(s):  
Cation Exchanger ◽  
Adsorption Chromatography ◽  
Rabbit Muscle ◽  
Experimental Conditions ◽  
Affinity Adsorption ◽  
Advantages And Disadvantages ◽  
Ph Range ◽  
Theoretical Considerations ◽  
Individual Enzyme ◽  
Elution Chromatography

1. A systematic procedure for the purification of enzymes by affinity-elution chromatography is described. Enzymes are adsorbed on a cation-exchanger, and eluted with ligands specific for the enzyme concerned. 2. All of the glycolytic and some related enzymes present in rabbit muscle can be purified by the affinity-elution technique. The pH range for adsorption and elution of each enzyme was found, and the effects of minor variations of conditions are described. 3. A description of experimental conditions suitable for affinity elution of each enzyme is given, together with special features relevant to each individual enzyme. 4. Theoretical considerations of affinity elution chromatography are discussed, including its limitations, advantages and disadvantages compared with affinity-adsorption chromatography. Possible developments are suggested to cover enzymes which because of their adsorption characteristics are not at present amenable to affinity-elution procedures.

scholarly journals Investigations of ternary complexes of Co(II) and Ni(II) with thiodiacetate anion and 1,10-phenanthroline or 2,2’-bipyridine in aqueous solutions

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Dariusz Wyrzykowski ◽  
Joanna Pranczk ◽  
Dagmara Jacewicz ◽  
Aleksandra Tesmar ◽  
Bogusław Pilarski ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Substitution Reactions ◽  
Experimental Conditions ◽  
Kinetic Measurements ◽  
Hydroxo Complexes ◽  
Binary Complexes ◽  
Vis Spectroscopy ◽  
Potentiometric Titration Method ◽  
The Stability ◽  
Ph Range

AbstractA potentiometric titration method (PT) and a stopped-flow kinetic technique monitored by a UV−Vis spectroscopy have been used to characterize the stability of series of Co(II)- and Ni(II)-thiodiacetato complexes, M(TDA), in the presence of 1,10-phenanthroline (phen) or 2,2’-bipyridine (bipy) in aqueous solutions. The stability constants of the binary (1:1), ternary (1:1:1) as well as the resulting hydroxo complexes were evaluated and compared to the corresponding oxydiacetate complexes. Based on the species distribution as a function of pH the relative predominance of the species in the system over a pH range was discussed. Furthermore, the kinetic measurements of the substitution reactions of the aqua ligands to phen or bipy in the coordination sphere of the binary complexes M(TDA) were performed in the 288–303 K temperature range, at a constant concentration of phen or bipy and at seven different concentrations of the binary complexes (0.2–0.5 mM). The kinetic stability of the M(TDA) complexes was discussed in relation to the experimental conditions and the kind of the auxiliary ligands (phen/bipy). Moreover, the influence of the type of primary ligand (thiodiacetate/oxydiacetate) on the substitution rate of the auxiliary ligands was also compared.

Some Experiments on Wet Steam Flow Visualization in Large Steam Turbine Blading

1976 ◽  
Vol 98 (3) ◽  
pp. 573-577 ◽  
Author(s):  
J. Krzyz˙anowski ◽  
B. Weigle
Keyword(s):  
Steam Turbine ◽  
Steam Flow ◽  
Light Sources ◽  
Phase Flow ◽  
Wet Steam ◽  
Experimental Conditions ◽  
Advantages And Disadvantages ◽  
Primary Droplet ◽  
Last Stage ◽  
Wet Steam Flow

In a series of experiments aimed at the visualization of the wet steam flow in the exhaust part of a 200 MW condensing steam turbine a set of periscopes and light sources was used. The aim of the experiment was: 1 – The investigation of the liquid-phase flow over the last stage stator blading of the turbine mentioned. 2 – The investigation of the gaseous-phase flow through the last stage blading at full and part load. The first part of the program partially failed due to the opaqueness of the wet steam atmosphere for the turbine load higher than 10–20 MW. The detailed experimental conditions will be described. An assessment of the primary droplet size will also be given. The preliminary results of the second part of the program will be outlined. The advantages and disadvantages of the equipment used will be discussed.

scholarly journals ADSORPTION OF PHOSPHATE IONS ON RED SLUDGE

2017 ◽  
Vol 60 (8) ◽  
pp. 80
Author(s):  
Svetlana M. Kramer ◽  
Mariya V. Terekhova ◽  
Inna V. Artamonova
Keyword(s):  
Hydrochloric Acid ◽  
Experimental Studies ◽  
Aluminum Production ◽  
Quantitative Composition ◽  
Experimental Conditions ◽  
Initial Concentration ◽  
Phosphate Ions ◽  
Frumkin’S Isotherm ◽  
Ph Range ◽  
Red Sludge

In work the possibility of red sludge (waste of aluminum production by Bayer's method) to adsorb phosphate ions from water solutions at various concentration of ions and in the pH range from 3 to 10 is studied. Relevance of use of red sludge for receiving on its basis of sorbents is reasoned. For identification of the studied object the qualitative and quantitative composition of red sludge was established by the method of the X-ray phase analysis. The technique of red slage activation by hydrochloric acid, and also an adsorption technique of phosphate ions on the red sludge surface is described. Experimental studies of adsorption of phosphate ions on the surface of the red slage activated by hydrochloric acid depending on рН and concentration of initial solution were conducted. The dependence of adsorption phosphate ions on the red slage activated by НСl on рН and on the initial concentration of phosphate ions in solution is presented. These dependences of a relative fraction of distribution of various ions of phosphoric acid on рН are given in work. The form of ion phosphate having the greatest adsorptive activity on the red slage activated by hydrochloric acid in experimental conditions is revealed. Experimental data on dependence of adsorption of phosphate ions on their initial concentration in solution are described by Frumkin's isotherm. The constant of the adsorptive balance, limit adsorption, the parameter of intermolecular interaction of the adsorbed particles are calculated. Optimum conditions for adsorption of phosphate ions on red slage are established.Forcitation:Kramer S.M., Terekhova M.V., Artamonova I.V. Adsorption of phosphate ions on red sludge. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 8. P. 80-83.

scholarly journals A comparative study of handwriting and computer typing in note-taking by university students

Comunicar ◽  
2016 ◽  
Vol 24 (48) ◽  
pp. 101-107 ◽  
Author(s):  
Estíbaliz Aragón-Mendizábal ◽  
Cándida Delgado-Casas ◽  
José-I. Navarro-Guzmán ◽  
Inmaculada Menacho-Jiménez ◽  
Manuel-F. Romero-Oliva
Keyword(s):  
Health Science ◽  
Science Students ◽  
Education Students ◽  
Experimental Conditions ◽  
Health Science Students ◽  
Advantages And Disadvantages ◽  
Common Strategy ◽  
Pencil And Paper ◽  
Los Grupos ◽  
Estudiantes Universitarios

Taking notes is a common strategy among higher education students, and has been found to affect their academic performance. Nowadays, however, the use of computers is replacing the traditional pencil-and-paper methodology. The present study aims to identify the advantages and disadvantages associated with the use of computer (typing) and pencil-and-paper (handwriting) for taking notes by college students. A total of 251 social and health science students participated in the study. Two experimental conditions were chosen: taking notes by hand (n=211), and taking notes by computer (n=40). Those that used computer-written notes performed better on tasks based on reproducing the alphabet, writing sentences, and recognizing words (p<.05). However, those using handwritten notes performed better on free recall tasks (p<.05). Differences between the two conditions were statistically significant rejecting the hypothesis of equality between groups (X2=60.98; p<.0001). In addition, the discriminant analysis confirmed that 77.3% of students were correctly classified by the experimental conditions. Although the computer allowed for greater velocity when taking notes, handwriting enhanced students’ grades when performing memory tasks. La toma de apuntes es una estrategia generalizada del alumnado de Educación Superior y se ha constatado su influencia en el rendimiento académico. El uso del ordenador está desplazando al método tradicional de lápiz y papel. El presente estudio pretende arrojar luz sobre las ventajas y los inconvenientes derivados del uso de uno u otro método en la toma de apuntes en las aulas universitarias. Un total de 251 estudiantes universitarios de ciencias sociales y ciencias de la salud participaron en el estudio. Se plantearon dos condiciones experimentales: toma de notas de forma manual (n=211) y de manera electrónica (n=40). Se hallaron diferencias a favor del grupo que usó el ordenador en las tareas basadas en completar el abecedario, escribir frases y reconocer palabras anotadas previamente (p<.05). Sin embargo, en la tarea de recuerdo libre los resultados reflejaron un mejor desempeño del grupo que tomó notas manualmente (p<.05). Se rechazó la hipótesis de igualdad entre los grupos (X2=60,98; p<.0001). Además, el análisis discriminante confirmó que el 77,3% de los alumnos fueron clasificados correctamente según su condición experimental. El uso del ordenador resultó muy útil cuando se trataba de anotar datos con rapidez; sin embargo, en las tareas de recuerdo los alumnos de escritura manual obtuvieron mejores puntuaciones que los de escritura electrónica.

scholarly journals Differential Pulse Polarographic Determination of Procymidone in Formulations and Wine

2002 ◽  
Vol 85 (3) ◽  
pp. 731-735 ◽  
Author(s):  
Neelam Y Sreedhar ◽  
Thommandru R Babu ◽  
Kethamreddy Samatha ◽  
Devarapalli Sujatha ◽  
Thenepalli Thriveni
Keyword(s):  
Reduction Process ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Experimental Conditions ◽  
Controlled Potential Electrolysis ◽  
Pulse Polarography ◽  
Half Wave ◽  
Single Well ◽  
Controlled Potential ◽  
Ph Range

Abstract The dicarboximide fungicide procymidone was studied systematically by using direct current polarography, cyclic voltammetry, differential pulse polarography (DPP), controlled potential electrolysis, and millicoulometry in the universal buffer medium with dimethylformamide as the solvent. Procymidone exhibited a single well-defined polarographic wave in the pH range 2.0–6.0, leading to the formation of the hydroxy compound. The overall reduction process was diffusion-controlled and adsorption-free. The variation of half-wave potential with pH, the concentration of the analyte, and other experimental conditions are described. The reduction mechanism proposed is an overall 4-electron process, in which the dicarboximide group is reduced. DPP was used to determine procymidone in agricultural formulations and wine at the optimum conditions found; a detection limit of 2.4 × 10−9M was estimated. The results obtained by the proposed method were also compared with those obtained by other methods.

scholarly journals THE INACTIVATION OF DILUTE SOLUTIONS OF CRYSTALLINE TRYPSIN BY X-RADIATION

1955 ◽  
Vol 38 (5) ◽  
pp. 581-598 ◽  
Author(s):  
Margaret R. McDonald
Keyword(s):  
Sulfuric Acid ◽  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Radiation Effects ◽  
Reaction Yield ◽  
X Rays ◽  
Dilute Solutions ◽  
Experimental Conditions ◽  
Ph Range ◽  
Ph Curve

The proteolytic activity of dilute solutions of clystalline trypsin is destroyed by x-rays, the amount of inactivation being an exponential function of the radiation dose. The reaction yield increases steadily with increasing concentration of trypsin, varying, as the concentration of enzyme is increased from 1 to 300 µM, from 0.068 to 0.958 micromole of trypsin per liter inactivated per 1000 r with 0.005 N hydrochloric acid as the solvent, from 0.273 to 0.866 with 0.005 N sulfuric acid as the solvent, and from 0.343 to 0.844 with 0.005 N nitric acid as the solvent. When the reaction yields are plotted as a function of the initial concentration of trypsin, they fall on a curve given by the expression Y α XK, in which Y is the reaction yield, X is the concentration of trypsin, and K is a constant equal to 0.46, 0.20, and 0.16, respectively, with 0.005 N hydrochloric, sulfuric, and nitric acids as solvents. The differences between the reaction yields found with chloride and sulfate ions in I to 10 µM trypsin solutions are significant only in the pH range from 2 to 4. The amount of inactivation obtained with a given dose of x-rays depends on the pH of the solution being irradiated and the nature of the solvent. The reaction yield-pH curve is a symmetrical one, with minimum yields at about pH 7. Buffers such as acetate, citrate, borate and barbiturate, and other organic molecules such as ethanol and glucose, in concentrations as low as 20 µM, inhibit the inactivation of trypsin by x-radiation. Sigmoid inactivation-dose curves instead of exponential ones are obtained in the presence of ethanol. The reaction yields for the inactivation of trypsin solutions by x-rays are approximately 1.5 times greater when the irradiation is done at 26°C. than when it is done at 5°C., when 0.005 N hydrochloric acid is the solvent. The dependence on temperature is less when 0.005 N sulfuric acid is used, and is negligible with 0.005 N nitric acid. The difficulties involved in interpreting radiation effects in aqueous systems, and in comparing the results obtained under different experimental conditions, are discussed.

scholarly journals Energy-loss magnetic chiral dichroism (EMCD): Magnetic chiral dichroism in the electron microscope

2008 ◽  
Vol 23 (10) ◽  
pp. 2582-2590 ◽  
Author(s):  
S. Rubino ◽  
P. Schattschneider ◽  
M. Stöger-Pollach ◽  
C. Hébert ◽  
J. Rusz ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Electron Microscope ◽  
Energy Loss ◽  
Magnetic Circular Dichroism ◽  
Magnetic Moments ◽  
Sample Collection ◽  
Experimental Conditions ◽  
Advantages And Disadvantages ◽  
A New Technique ◽  
Circular Dichroïsm

A new technique called energy-loss magnetic chiral dichroism (EMCD) has recently been developed [P. Schattschneider, et al. Nature441, 486 (2006)] to measure magnetic circular dichroism in the transmission electron microscope (TEM) with a spatial resolution of 10 nm. This novel technique is the TEM counterpart of x-ray magnetic circular dichroism, which is widely used for the characterization of magnetic materials with synchrotron radiation. In this paper we describe several experimental methods that can be used to measure the EMCD signal [P. Schattschneider, et al. Nature441, 486 (2006); C. Hébert, et al. Ultramicroscopy108(3), 277 (2008); B. Warot-Fonrose, et al. Ultramicroscopy108(5), 393 (2008); L. Calmels, et al. Phys. Rev. B76, 060409 (2007); P. van Aken, et al. Microsc. Microanal.13(3), 426 (2007)] and give a review of the recent improvements of this new investigation tool. The dependence of the EMCD on several experimental conditions (such as thickness, relative orientation of beam and sample, collection and convergence angle) is investigated in the transition metals iron, cobalt, and nickel. Different scattering geometries are illustrated; their advantages and disadvantages are detailed, together with current limitations. The next realistic perspectives of this technique consist of measuring atomic specific magnetic moments, using suitable spin and orbital sum rules, [L. Calmels, et al. Phys. Rev. B76, 060409 (2007); J. Rusz, et al. Phys. Rev. B76, 060408 (2007)] with a resolution down to 2 to 3 nm.

scholarly journals A study of the kinetics and mechanism of rabbit muscle l-glycerol 3-phosphate dehydrogenase

1974 ◽  
Vol 143 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Philip Bentley ◽  
F. Mark Dickinson
Keyword(s):  
Basic Mechanism ◽  
Kinetics And Mechanism ◽  
Dihydroxyacetone Phosphate ◽  
Rabbit Muscle ◽  
Kinetics Of Oxidation ◽  
Mechanism Of Catalysis ◽  
Glycerol 3 Phosphate Dehydrogenase ◽  
Ph Range ◽  
Kinetics Of

1. The kinetics of oxidation of l-glycerol 3-phosphate by NAD+and of reduction of dihydroxyacetone phosphate by NADH catalysed by rabbit muscle glycerol 3-phosphate dehydrogenase were studied over the range pH6–9. 2. The enzyme was found to catalyse the oxidation of glyoxylate by NAD+at pH8.0 and the kinetics of this reaction were also studied. 3. The results are consistent with a compulsory mechanism of catalysis for glycerol 3-phosphate oxidation and dihydroxyacetone phosphate reduction in the intermediate regions of pH, but modifications to the basic mechanism are required to fully explain results at the extremes of the pH range, with these substrates and for glyoxylate oxidation at pH8.0.

scholarly journals Thiol reduction of human α2-macroglobulin. The subunit structure

1972 ◽  
Vol 127 (1) ◽  
pp. 187-197 ◽  
Author(s):  
J. M. Jones ◽  
J. M. Creeth ◽  
R. A. Kekwick
Keyword(s):  
Molecular Weight ◽  
Large Scale ◽  
Sedimentation Equilibrium ◽  
Subunit Structure ◽  
Experimental Conditions ◽  
A Value ◽  
Α2 Macroglobulin ◽  
A Subunit ◽  
Normal Human ◽  
Ph Range

1. Human α2-macroglobulin was prepared from a fraction obtained during the large-scale separation of normal human plasma proteins for clinical use. 2. Sedimentation-equilibrium measurements indicated a molecular weight of 725000. A value of 18.1S was obtained for s020,w. 3. The dissociation that occurs in the pH range 4.5–2.5 and in the region of neutrality in urea-containing solutions is consistent with a dimeric structure of the molecule. 4. The effects of the thiol reagents mercaptoethanol, mercaptoethylamine and N-acetylcysteine were investigated over a range of experimental conditions. Distinct components having sedimentation coefficients of 15, 12 and 8.5S were identified. 5. Conditions were found under which limited reduction with thiol liberated a subunit with a molecular weight approximately one-quarter of that of the intact molecule. This subunit retains the serological specificity of the whole molecule.

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