The Experts below are selected from a list of 1643988 Experts worldwide ranked by ideXlab platform
Jan Ake Jonsson - One of the best experts on this subject based on the ideXlab platform.
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role of octanol water partition coefficients in extraction of ionisable organic compounds in a supported liquid membrane with a stagnant acceptor
2000Co-Authors: Luke Chimuka, Lennart Mathiasson, Jan Ake JonssonAbstract:Abstract The correlation between the logarithm of the octanol–water partition coefficients (log K ow ) and the logarithm of partition coefficients in di- n -hexyl ether–water and n -undecane–water (log K D ) which are used as organic solvents in a supported liquid membrane extraction method with a stagnant acceptor was studied for a group of 17 s -triazines. A linear relationship between log K ow and log K D was found. A plot of the extraction efficiency obtained in a supported liquid membrane and their octanol–water partition coefficients of the above compounds together with phenoxyacids, phenols and local anaesthetics resulted into an approximately bell-shaped relationship. Maximum extraction efficiency was obtained for those compounds with log K ow values ∼3.0. Those compounds with high octanol–water partition coefficients were easily dissolved in the supported liquid membrane but were difficulty to strip into the acceptor solution, thus giving lower extraction efficiency. In contrast, those compounds with low octanol–water partition coefficients gave low extraction efficiency due to poor dissolution in the membrane liquid. Implications of log K ow values on the analytical application of the SLM technique are discussed.
L Schultz - One of the best experts on this subject based on the ideXlab platform.
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high critical current density and its field dependence in mixed rare earth nd eu gd ba2cu3o7 δ thin films
2004Co-Authors: Chuanbing Cai, B Holzapfel, Jens Hanisch, L Fernandez, L SchultzAbstract:Compared with mono-rare earth 123 films, ternary rare earth (Nd,Eu,Gd)Ba2Cu3O7−δ (NEG123) films show higher critical current density (Jc) and improved irreversibility field (Hirr), but no increase in the characteristic field corresponding to a crossover from a low-field plateau to a linear region in a log Jc–log H plot. At intermediate fields, Jc vs H scales as H(−0.5±0.05) for NEG123, in contrast to H(−0.73±0.05) for mono-rare earth samples such as Gd123. The slow power decay of Jc vs H together with the improved Jc and Hirr strongly implies that extra flux pinning centers exist in NEG123, which are thought to be noncorrelated stress fields induced by lattice mismatch.
Jin Ougiyanagi - One of the best experts on this subject based on the ideXlab platform.
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solvent effect on distribution ratio of pd ii in supercritical carbon dioxide extraction and solvent extraction using 2 methyl 8 quinolinol
2003Co-Authors: Jin Ougiyanagi, Yoshihiro Meguro, Zenko Yoshida, Hisanori Imura, Kousaburo OhashiAbstract:Abstract The distribution ratio ( D M ) of Pd(II) by the extraction with 2-methyl-8-quinolinol (HMQ) was determined using the supercritical carbon dioxide medium (SF-CO 2 ) and organic solvent media such as perfluoro-methylcyclohexane, heptane, cyclohexane, carbon tetrachloride and benzene. From experimental results of the slopes of log D M versus pH plot and log D M versus HMQ concentration plot, the extracted species both in the SF-CO 2 extraction (SFE) and the solvent extraction (SE) were determined to be Pd(MQ) 2 . The distribution constant of HMQ ( K D,HMQ ) in the SFE and SE systems were determined from the dependence of the distribution ratio of HMQ ( D HMQ ) on the pH. A linear relationship was observed between log K D,HMQ and the solubility parameter ( δ ) of the extraction medium based on the regular solution theory in both the SFE using SF-CO 2 at the pressure of 8.5–40 MPa and the SE systems. The difference in the slope of the log K D,HMQ versus δ plot between the SFE and the SE systems is attributable to the extent of the specific interaction of the solute HMQ with the solvent molecules, i.e. CO 2 molecules and the organic solvent molecules. The D M versus δ plot obtained under a given extraction condition using SF-CO 2 (11–40 MPa) and organic solvents showed clear linearity. The D M obtained using SF-CO 2 at relatively low pressure range from 8.5 to 11 MPa was independent of the pressure and the δ of SF-CO 2 , which coincides with the experimental fact that the solubility of Pd(MQ) 2 in the SF-CO 2 at 8.5–11 MPa was practically constant.
Luke Chimuka - One of the best experts on this subject based on the ideXlab platform.
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role of octanol water partition coefficients in extraction of ionisable organic compounds in a supported liquid membrane with a stagnant acceptor
2000Co-Authors: Luke Chimuka, Lennart Mathiasson, Jan Ake JonssonAbstract:Abstract The correlation between the logarithm of the octanol–water partition coefficients (log K ow ) and the logarithm of partition coefficients in di- n -hexyl ether–water and n -undecane–water (log K D ) which are used as organic solvents in a supported liquid membrane extraction method with a stagnant acceptor was studied for a group of 17 s -triazines. A linear relationship between log K ow and log K D was found. A plot of the extraction efficiency obtained in a supported liquid membrane and their octanol–water partition coefficients of the above compounds together with phenoxyacids, phenols and local anaesthetics resulted into an approximately bell-shaped relationship. Maximum extraction efficiency was obtained for those compounds with log K ow values ∼3.0. Those compounds with high octanol–water partition coefficients were easily dissolved in the supported liquid membrane but were difficulty to strip into the acceptor solution, thus giving lower extraction efficiency. In contrast, those compounds with low octanol–water partition coefficients gave low extraction efficiency due to poor dissolution in the membrane liquid. Implications of log K ow values on the analytical application of the SLM technique are discussed.
Janusz Skrzat - One of the best experts on this subject based on the ideXlab platform.
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error estimation of the fractal dimension measurements of cranial sutures
2006Co-Authors: A Z Gorski, Janusz SkrzatAbstract:The fractal exponents used to quantify the complexity of cranial sutures were computed for 17 coronal and 17 sagittal sutures of adults from different populations, using the box-counting algorithm. This paper discusses the main sources of error for the fractal exponents, and gives the error estimates. We then compare our results with those obtained by other authors. We suggest that the usual error estimates implied by the standard deviation for the regression line are too low. We emphasize the crucial role played by the choice of regression line in the log–log plot. For the coronal and sagittal sutures we found mean fractal dimensions of 1.48 and 1.56, respectively. Our values are close to the value for Brownian random walk.
