Urea Formaldehyde Kinetic Studies. III. Polarographic Studies in Dilute Solution

1953 ◽  
Vol 75 (3) ◽  
pp. 574-576 ◽  
Author(s):  
Lloyd E. Smythe
Keyword(s):  
Urea Formaldehyde ◽  
Kinetic Studies ◽  
Dilute Solution

Polarographic Urea--Formaldehyde Kinetic Studies

1949 ◽  
Vol 71 (11) ◽  
pp. 3731-3733 ◽  
Author(s):  
George A. Crowe ◽  
Cecil C. Lynch
Keyword(s):  
Urea Formaldehyde ◽  
Kinetic Studies

Article

1998 ◽  
Vol 76 (2) ◽  
pp. 152-157
Author(s):  
Catherine E Drennan ◽  
Rachelle J Hughes ◽  
Vincent C Reinsborough ◽  
Oladega O Soriyan
Keyword(s):  
Surface Tension ◽  
Critical Micelle Concentration ◽  
Mixed Micelles ◽  
Anionic Surfactants ◽  
Sodium Dodecyl ◽  
Surfactant Solution ◽  
Kinetic Studies ◽  
Stopped Flow ◽  
Dilute Solution ◽  
Surfactant Micelles

Kinetic studies through stopped-flow spectroscopy were undertaken in the dilute solution range of anionic surfactants where pronounced rate enhancement or inhibition of Ni2+-ligand complexations is often observed at surfactant concentrations much below the critical micelle concentration (CMC). The results are interpreted in terms of Ni-surfactant micelles as the agents responsible for the rate changes in dilute surfactant solution. At higher surfactant concentrations these micelles are transformed into mixed micelles (counterion and size changes), eventually becoming normal surfactant micelles close to the CMC. Surface tension, dye solubility, conductivity, and fluorescent probe investigations support this interpretation.Key words: micellar catalysis, sodium dodecyl sulfate, micelles, critical micelle concentration, premicelles, Ni2+-ligand complexations.

The reactions of hydrazines with trans-Dichlorobis(ethylenediamine)cobalt(III)chloride, and the isolation and kinetic studies of a Chlorobis(ethylenediamine)methylhydrazinecobalt(III) isomer

1973 ◽  
Vol 26 (9) ◽  
pp. 1923 ◽  
Author(s):  
SC Chan ◽  
CK Lee
Keyword(s):  
Electron Transfer ◽  
Kinetic Studies ◽  
Intramolecular Electron Transfer ◽  
Dilute Solution ◽  
Dilute Solutions ◽  
Spectroscopic Observations ◽  
Acid And Base ◽  
Concentrated Solution ◽  
Kinetics Of ◽  
Hydrolysis Of

The reactions of hydrazine, methylhydrazine, and 1,1-dimethylhydrazine with trans-dichlorobis(ethylenediamine)cobalt(III) chloride in concentrated and dilute solutions are studied. In concentrated solution, there is a reduction by hydrazine to form the insoluble polymeric [CoII(N2H4)2Cl2]n, a substitution by methylhydrazine to form chlorobis(ethylenediamine)methylhydrazinecobalt(III) chloride, and a disproportionation with 1,1-dimethylhydrazine to form tris(ethylenediamine)cobalt(III) chloride. In dilute solution, the reaction observed is a hydroxide substitution by hydrolysis of 1,1- dimethylhydrazine, a reduction to soluble cobalt(II)-ethylenediamine species with hydrazine, and a mixture of both processes for methylhydrazine. The chlorobis(ethylenediamine)methylhydrazinecobalt-(III) chloride obtained is a new complex, and is assigned a cis configuration on the basis of spectroscopic observations. The kinetics of its intramolecular electron-transfer, as well as its acid and base hydrolyses are also studied.

Urea—Formaldehyde Kinetic Studies

1948 ◽  
Vol 70 (11) ◽  
pp. 3795-3797 ◽  
Author(s):  
George A. Crowe ◽  
Cecil C. Lynch
Keyword(s):  
Urea Formaldehyde ◽  
Kinetic Studies

scholarly journals The purification and regulatory properties of α-oxoglutarate dehydrogenase from Acinetobacter lwoffi

1973 ◽  
Vol 135 (1) ◽  
pp. 215-223 ◽  
Author(s):  
Malcolm G. Parker ◽  
P. David J. Weitzman
Keyword(s):  
Protein Concentration ◽  
Analytical Ultracentrifugation ◽  
Energy Charge ◽  
Kinetic Studies ◽  
Dilute Solution ◽  
Site Of Action ◽  
Oxoglutarate Dehydrogenase ◽  
Sites Of Action ◽  
High Degree ◽  
Regulatory Properties

The α-oxoglutarate dehydrogenase multienzyme complex was purified from Acinetobacter lwoffi to a high degree of homogeneity as shown by gel electrophoresis and analytical ultracentrifugation. Sedimentation-velocity analyses gave s20,w values which increased with increasing protein concentration, suggesting dissociation of the complex in dilute solution. The maximum s20,w value thereby obtained and the value determined by active enzyme centrifugation were both in the range 28–29S. Electron micrographs of the complex indicated a molecular diameter of 20–22nm (200–220Å). The overall activity of the complex was inhibited by NADH, and kinetic studies indicated sites of action on the first and third enzyme components. AMP and ADP relieved this inhibition and also stimulated enzyme activity. Assays specific for the first enzyme component showed this to be the site of action of the adenylates. The activity of the complex varied with energy charge in a manner consistent with its role in energy metabolism.

Computer averaging of lattice images of poly-4-methyl-pentene-1 (P4mp1): Noise created artifacts

1987 ◽  
Vol 45 ◽  
pp. 388-389
Author(s):  
P. Pradère ◽  
J.F. Revol ◽  
R. St. John Manley
Keyword(s):  
Low Dose ◽  
Polymer Concentration ◽  
Processing System ◽  
Limiting Factor ◽  
Dilute Solution ◽  
New Techniques ◽  
Dose Unit ◽  
Lattice Images ◽  
Dose Imaging ◽  
Imaging Conditions

Although radiation damage is the limiting factor in HREM of polymers, new techniques based on low dose imaging at low magnification have permitted lattice images to be obtained from very radiation sensitive polymers such as polyethylene (PE). This paper describes the computer averaging of P4MP1 lattice images. P4MP1 is even more sensitive than PE (total end point dose of 27 C m-2 as compared to 100 C m-2 for PE at 120 kV). It does, however, have the advantage of forming flat crystals from dilute solution and no change in d-spacings is observed during irradiation.Crystals of P4MP1 were grown at 60°C in xylene (polymer concentration 0.05%). Electron microscopy was performed with a Philips EM 400 T microscope equipped with a Low Dose Unit and operated at 120 kV. Imaging conditions were the same as already described elsewhere. Enlarged micrographs were digitized and processed with the Spider image processing system.

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