Pearson and Mawby softness parameter

Jones and Vaughn (1978) used intraperitoneal LD50 data in mice and oral LD50 data in rats (Hg2+) and mice (Ag +, Au +) to develop 4 QSARs for the Pearson and Mawby softness parameter (Op) that predicted mouse LD50 values for groups of 4,7, 17, and 28 divalent cations (Table 5.16). The coefficients of determination decreased and the standard error increased as the number divalent cations increased from 4 to 28 (Table 5.16). The test system used to develop the Jones and Vaughn (1978) QSARs is listed in Table 5.15. 

Williams and Turner (1981) used a compilation of intraperitoneal-dosed mouse LD50 data available in the literature to develop a QSAR for the Pearson and Mawby softness parameter (Op) to predict the LD50 value of 25 mono-, di-, and trivalent cations to mice (Table 5.1). The 25 cations used to develop the Williams and Turner (1981) QSAR are listed in Table 5.15. 

Intraperitoneal (ip) LDjq data in mice and oral LD50 data in rats (Hg +) and mice (Ag +, Au +) 

Compilation of intraperitoneal (ip) mouse LD50 data available in the literature 

14-day ip LDjq data in mice and 4-day LCjq data from dietary exposures to Drosophila melanogaster 

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McCloskey et al. (1996) and Newman and McCloskey (1996) QSARs for Predicting Cation Toxicity Using Standard Reduction-Oxidation Potential or a Combination of Standard Reduction-Oxidation Potential, Atomic Number, and Ionization Potential Differential or Pearson and Mawby Softness Parameter... 

Tatara et al. (1997,1998) QSARs for predicting cation toxicity using standard reduction-oxidation potential alone or in combinations with standard reduction-oxidation potential, atomic number, ionization potential differential, covalent index, logarithm of the first hydrolysis constant, or Pearson and Mawby softness parameter alone or in combination with logarithm of the first hydrolysis constant... 

Op is the Pearson and Mawby softness parameter. logl Tonlts th logarithm of the first hydrolysis constant. 

Jones and Vaughn (1978) Pearson and Mawby Softness Parameter (Op) QCARs... 

Khangarot and Ray (1989) did not report any QSARs for the Pearson and Mawby softness parameter (Op). However, they did use linear regression analysis to develop... 

Segner et al. (1994) did not report any QSARs for the Pearson and Mawby softness parameter (Op). However, they did provide a correlation coefficient to describe the relationship between the toxicity of 6 divalent cations and reduction in uptake of neutral red dye (NR50) for fish culture cells. Their correlation coefficients were converted to a coefficient of determination, r =0.86. Their fish cultures were a fibroblast-like cell line (R1 cells) from rainbow trout (Oncorhynchus mykiss) liver tissue. Their 6 cations are listed in Table 5.15. 

Van Kolck et al. (2008) developed 4 QSARs to predict 96-hour LC50 values of 5 cations to the mussel, Mytilis edulis and 4 QSARs to predict the 96-hour LC50 values of 6 cations to the mussel Perna viridis (Table 5.17). The Pearson and Mawby softness parameter (Op) was used to develop 2 of these 8 QSARs, but neither QSAR produced very high C values (Table 5.18). 

QCARs for Predicting Cation Toxicity and Bioconcentration Factors for the Mussels, Mytilis edulis and Perna viridis Using the Covalent Radius, Logarithm of the First Hydrolysis Constant, Pearson and Mawby Softness Parameter, and the Ionic Index... 

Table 5.19 lists the 21 QSARs that only used the Pearson and Mawby softness parameter (Op) to predict cation toxicity. Two of these QSARs are duplicates. The Turner et al. (1983) QSAR with r =0.360 is a duplicate of the Williams et al. (1982) QSAR with the same r value. The Turner et al. (1985) QSAR with r =0.879 is a duplicate of the Turner et al. (1983) QSAR with the same r value. The Jones and Vaughn (1978) QSAR for Ag+, Am, Cd " and Hg had the highest perhaps because of their proximity in the periodic table. The Turner et al. (1983) QSAR for Mn +, cm+, Ni +, Cu +, zm+, Cd +, Hg +and Pb " had the second highest r, perhaps because Mn +, Co +, NE+, and Zn " were in row 4 of the periodic table and Cd +, Hg + and Pm+ were in close proximity. For the Jones and Vaughn (1978) and Turner et al. (1983) references with 4 and 3 QSARs, respectively, the r decreased as the number of divalent cations increased (Table 5.18). The Babich et al. (1986) and Magwood and George (1996) QSARs both had high r and almost identical cations. The Babich et al. (1986) QSAR had almost identical cations to those used for the Turner et al. (1983) QSAR with r =0.879 (Table 5.18). The Enache et al. (1999) QSAR also had a high r. However, the Mendes et al. (2010) QSAR with a high r was the best for the highest number (18) of cations (Table 5.19).

Log metal hydroxide solubility Ionization potential Allred-Rochow electronegativity Pauling s electronegativity Mulliken Electronegativity Pearson and Mawby softness parameter The heat of formation of inorganic oxides The heat of formation of aqueous ion Atomic number... 

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