Search results for "Concentration."
showing 10 items of 1849 documents
Extraction of glyphosate by a supported liquid membrane technique.
2000
The possible application of the supported liquid membrane (SLM) technique for the extraction of glyphosate is presented. For the extraction of this compound the SLM system has been applied with utilisation of Aliquat 336 as a cationic carrier incorporated into the membrane phase. The extraction efficiency of glyphosate [N-(phosphonomethyl)glycine] is dependent on the donor phase pH, carrier concentration in the organic phase and NaCl concentration in the acceptor phase. The optimal extraction conditions are: donor phase pH>11, acceptor phase of 2 M NaCl solution and the organic phase composed of 20% (w/w) Aliquot 336 solution in di-hexyl ether. Counter-coupled transport of chloride anions f…
Global distributions of diazotrophs abundance and biomass - Depth integrated values computed from a collection of source datasets - Contribution to t…
2013
The MAREDAT atlas covers 11 types of plankton, ranging in size from bacteria to jellyfish. Together, these plankton groups determine the health and productivity of the global ocean and play a vital role in the global carbon cycle. Working within a uniform and consistent spatial and depth grid (map) of the global ocean, the researchers compiled thousands and tens of thousands of data points to identify regions of plankton abundance and scarcity as well as areas of data abundance and scarcity. At many of the grid points, the MAREDAT team accomplished the difficult conversion from abundance (numbers of organisms) to biomass (carbon mass of organisms). The MAREDAT atlas provides an unprecedente…
Global distributions of diazotrophs nitrogen fixation rates - Depth integrated values computed from a collection of source datasets - Contribution to…
2013
The MAREDAT atlas covers 11 types of plankton, ranging in size from bacteria to jellyfish. Together, these plankton groups determine the health and productivity of the global ocean and play a vital role in the global carbon cycle. Working within a uniform and consistent spatial and depth grid (map) of the global ocean, the researchers compiled thousands and tens of thousands of data points to identify regions of plankton abundance and scarcity as well as areas of data abundance and scarcity. At many of the grid points, the MAREDAT team accomplished the difficult conversion from abundance (numbers of organisms) to biomass (carbon mass of organisms). The MAREDAT atlas provides an unprecedente…
Adsorption of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) by goethite.
2014
Interaction between the goethite surface and 4-chloro-2-methylphenoxyacetic acid (MCPA) herbicide was studied using density functional theory (DFT) calculations combined with molecular dynamics (MD). The important step made here lies in the use of a periodic DFT method enabling the study of a mineral surface of different protonation states, in strong contrast with previous molecular modeling studies limited to single protonation state corresponding to the point of zero charge. Different surface OH groups and MCPA proton states were used to mimic the strong effects of pH on the outer- and inner-sphere surface complexes that are theoretically possible, together with their binding energies, an…
Susceptibility and resistance to ethanol in Saccharomyces strains isolated from wild and fermentative environments
2010
11 pages, 3 figures, 3 tables.-- Article first published online: 8 SEP 2010
The dynamics of privatization and regulation of water services: a comparative study of two Spanish regions
2013
As in other economic activities, privatization of water delivery has not resulted in the retreat of the public sector, but rather a change in the way in which the government intervenes in the water industry. This paper illustrates this situation by comparing urban water services in two Spanish regions, Andalusia and Catalonia. Water service delivery is structured very differently in these two regions with respect to private involvement, the degree of market concentration and, as a result, problems in competition. The characteristics of the two regions' respective regulatory agencies reflect the different paths taken to privatization: in Catalonia private firms have much more tradition and o…
Capacity of Gentamicin-Treated Pseudomonas aeruginosa to Induce Granulocyte Locomotion
1982
In protection against an invading parasite the host’s granulocytes play an essential role. To exert their defense the phagocytes have to be attracted to the site of parasite invasion. We have shown that Pseudomonas aeruginosa ATCC 27853 and other clinical isolates of this species can induce granulocyte migration, either directly or via generation of chemotactic activity in serum [1].
Green Synthesis, Molecular Characterization and Associative Behavior of Some Gemini Surfactants without a Spacer Group.
2013
A series of new gemini surfactants without a spacer group, disodium 2,3-dialkyl-1,2,3,4-butanetetracarboxylates, were synthesized in a green chemistry context minimizing the use of organic solvents and applying microwaves (MW) when activation energy was required. Once the desired architecture was confirmed by means of the nuclear magnetic resonance technique (1H-NMR, 1H-1H COSY) for all the studied surfactants, the critical micellization concentration was determined by conductance measurements. The diffusion coefficient of micelles formed by the four compounds was characterized using pulsed field gradient (PFG)-NMR. Diffusion coefficients were found to be dependent on the concentration and …
Compatibility of surfactants with activated-persulfate for the selective oxidation of PAH in groundwater remediation
2017
Abstract Surfactants foam technology can improve the in situ remediation of hydrophobic organic contaminants by enhancing their solubility and the delivery of remediation chemicals. However, the presence of surfactants may impair the effectiveness of the selective oxidation of those contaminants. To tackle the issue, kinetics and selectivity of phenanthrene (PHE) oxidation in aqueous suspensions and its affecting factors including surfactant concentration (CS) and nature, temperature and persulfate (PS) concentration were studied. Significant differences in selectivity were observed between surfactants, reflecting Coulomb interactions with the anionic oxidizers. Lauryl Betaine (LB) stood ou…
Intra- and extra-cellular DNA damage by harmine and 9-methyl-harmine
2014
It is known that b-carbolines are able to produce photosensitized damage in cell-free DNA, but there is little information on their effects on cellular DNA. Therefore, we have analyzed the DNA damage produced by harmine and 9-methyl-harmine under UVA irradiation in V79 cells, together with the associated generation of micronuclei and photocytotoxicity. The results indicate that the most frequent photoproducts generated in the cellular DNA are modified purines such as 8-oxo-7,8-dihydroguanine. Only relatively few single-strand breaks were observed. CPDs were absent, although they were generated in cell-free DNA irradiated under the same conditions. The overall extent of DNA damage in the cel…