Results 261 to 270 of about 86,854 (308)
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Desmutagenic effect of humic acid
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 1986In the present study, humic acid was not found to be mutagenic and did not inhibit spontaneous mutation. It did, however, inhibit the mutagenicities of benzo[a]pyrene and 3-aminoanthracene (+S9 mix), but not the mutagenicities of 4NQO, AF-2 and MNNG (-S9 mix).
T, Sato, Y, Ose, H, Nagase
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Environmental Toxicology and Chemistry, 1991
Abstract Iodide binding by humic acid was studied. The reaction was dose, temperature and pH dependent. A maximum binding of 88% was reached with 2 mg humic acid in 0.15 M Tris buffer. The efficiency of iodide binding by the buffer becomes higher whenever the buffer is slightly alkaline.
Tien-Shang Huang, Fung-Jou Lu
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Abstract Iodide binding by humic acid was studied. The reaction was dose, temperature and pH dependent. A maximum binding of 88% was reached with 2 mg humic acid in 0.15 M Tris buffer. The efficiency of iodide binding by the buffer becomes higher whenever the buffer is slightly alkaline.
Tien-Shang Huang, Fung-Jou Lu
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Methylation of Humic Acid Fractions
Science, 1978A new three-step permethylation procedure for humic acid fractions has been developed. In the first step, carboxylic acid groups are methylated with diazomethane in dimethylformamide; in the second step, hydroxyl groups are methylated with methyl iodide and dimethyl sulfinyl carbanion in dimethylformamide; and in the third step, acidic groups ...
R L, Wershaw, D J, Pinckney
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Americium Binding to Humic Acid
Environmental Science & Technology, 2001The binding of americium (Am) by peat humic acid (PHA) has been investigated at Am concentrations between 10(-1) and 10(-7) M at pH approximately 2.6 in the presence and absence of Cu as a competing ion. Cu-PHA binding was also investigated in order to derive independent binding constants for use in modeling the competitive binding studies.
Peters, Adam J. +2 more
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2005
Humic acids are iodinated by elemental iodine and, if the iodine is present as iodide, by peroxidase-mediated reactions. It is demonstrated that iodination of humic acids leads to a product with a uniform distribution of iodine. It could not be unambiguously verified whether the enzymatically mediated iodination is a direct reaction between a ...
Jesper V. Christiansen, Lars Carlsen
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Humic acids are iodinated by elemental iodine and, if the iodine is present as iodide, by peroxidase-mediated reactions. It is demonstrated that iodination of humic acids leads to a product with a uniform distribution of iodine. It could not be unambiguously verified whether the enzymatically mediated iodination is a direct reaction between a ...
Jesper V. Christiansen, Lars Carlsen
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Electrophoretic aggregation of humic acid
Journal of Chromatography A, 2004Capillary electrophoresis (CE) has been used to characterize humic acid (HA) aggregation. It was found that when pumping HA solution through the capillary at a constant flow rate with no electric field, the number of spikes could be reduced by filtration of the solution. Applying high voltage (30 kV), the amount of spikes increased again.
Monika, Ubner +3 more
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Humic acid: Inhibitor of plasmin
Science of The Total Environment, 1992Synthetic humic acid, well water humic acid and commercial humic acid (Aldrich) all have the ability to inhibit human plasmin activity. At a concentration of 20 micrograms/ml, all three species will result in 93%, 70% and 40% of residual plasmin activity, respectively. The components of humic acid, such as protocatechuic acid, resorcinol, vanillic acid
F J, Lu, Y S, Lee
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Antiviral properties of humic acids
Experientia, 1972Es wird ein antiviraler Effekt von Ammoniumhumat gegenuber Coxsackiervirus A9 in FL-Zellkulturen nachgewiesen. Die antivirale Wirkung ist auf den Humatanteil des Molekuls zuruckzufuhren.
R, Klöcking, M, Sprössig
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Adsorption of Humic Substances on Goethite: Comparison between Humic Acids and Fulvic Acids
Environmental Science & Technology, 2006The adsorption of humic acids (HA) to goethite (at pH 3-11) and the proton co-adsorption (at pH 4.0, 5.5, and 7.0) were measured, and the results were compared to those of fulvic acids (FA). Compared to FA, the adsorption of HA is stronger and more ionic strength dependent. The adsorption of both HA and FA decreases with increasing pH.
Weng, L.P. +3 more
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Effect of humic acid source on humic acid adsorption onto titanium dioxide nanoparticles
Science of The Total Environment, 2014In many studies, different humic acid (HA) sources are used interchangeably to evaluate the effect of organic matter on geochemical processes in the environment. This research looks more specifically at the effect of HA source on HA adsorption onto nano-TiO2 and how HA adsorption affects the fate and transport of nano-TiO2.
Mohamed, Erhayem, Mary, Sohn
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