| 11. |
- Andersson, Patrik, et al.
(författare)
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An introduction to QSARs
- 2006
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Ingår i: Using chemistry in environmental and health risk assessment. - : US-AB Universitetsservice, Stockholm. - 9171784144 ; , s. 51-74
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Bokkapitel (refereegranskat)
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| 12. |
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| 13. |
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| 14. |
- Andersson, Patrik, et al.
(författare)
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Multivariate modeling of polychlorinated biphenyl-induced CYP1A activity in hepatocytes from three different species : ranking scales and species differences
- 2000
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 19:5, s. 1454-1463
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Tidskriftsartikel (refereegranskat)abstract
- Cytochrome P4501A–induced activity of 20 selected polychlorinated biphenyls (PCBs) was evaluated by measuring ethoxyresorufin-O-deethylase and methoxyresorufin-O-demethylase activities induced in the hepatocytes of cynomolgus monkeys, male castrated pigs, and chicken embryos. Quantitative structure-activity relationships have been established, including 52 physi-cochemical parameters and different measures of the dose-response curves. Relative effect potencies are predicted for the 154 tetra-to hepta-PCBs and reported for the most potent congeners according to both EC50 and maximal response values. Important physicochemical parameters of the PCBs as related to the modeled activity are parts of their ultraviolet absorption spectra, the Henry's law constant, the ionization potential, and the octanol-water partition coefficient. Interspecies differences were found in terms of varied sensitivity to different structural subgroups of the compounds. The chicken hepatocyte assay showed the most specific structure-activity relationship, with high activity for the non-ortho PCBs, whereas the pig hepatocytes responded even for some di- to tetra-ortho PCBs. An interspecies response, the principal induction potency, is presented for the 41 most potent PCBs. These responses showed strong correlation with the toxic equivalency factors and are likely to be useful in risk assessment of the compounds.
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| 15. |
- Andersson, Patrik, et al.
(författare)
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The internal barriers of rotation for the 209 polychlorinated biphenyls
- 1997
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Ingår i: Environmental Science and Pollution Research. - 0944-1344 .- 1614-7499. ; 4:2, s. 75-81
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Tidskriftsartikel (refereegranskat)abstract
- The internal barrier of rotation (Erot) was calculated for all 209 polychlorinated biphenyls (PCBs) by using a semi-empirical method, viz. the Austin Model 1 (AM1) Hamiltonian. The difference in total energy between a forced planar state and an optimised twisted structure was defined as Erot. The Erot values were in the range of 8.33 to 483 kJ/mol, and were significantly influenced by the number of chlorine atoms in ortho position. An additional structural characteristic of the PCBs influencing Erot of ortho substituted congeners was substitution by chlorine atoms in vicinal meta positions, which is assumed to prevent outward bending of ortho substituents. This so-called buttressing effect contributed with 4 to 31 kJ/mol per added chlorine atom. In conclusion, the internal barrier of rotation, calculated for all 209 PCBs, provides an important structure dependent physico-chemical parameter for multivariate modelling of future quantitative structure-activity and structure-property relationships (QSARs/QSPRs).
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| 16. |
- Andersson, Patrik, et al.
(författare)
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Ultraviolet absorption characteristics and calculated semi-empirical parameters as chemical descriptors in multivariate modelling of polychlorinated biphenyls
- 1996
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Ingår i: Journal of Chemometrics. - 0886-9383 .- 1099-128X. ; 10:2, s. 171-185
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Tidskriftsartikel (refereegranskat)abstract
- The structural variation within the polychlorinated biphenyls (PCBs) was characterized by using principal component analysis (PCA). A multivariate model was evolved from 52 physicochemical descriptors including measured ultraviolet (UV) absorption spectra, calculated semiempirical parameters (AM1) and properties captured from the literature. Parameters calculated by using the AM1-Hamiltonian were e.g. heat of formation, dipole moments, ionization potential and the barrier of internal rotation. The UV spectra were measured and digitized in the range 200-300 nm. The multivariate model revealed that most of the information within the set of physicochemical parameters was related to molecular size. Descriptors depending on size were e.g. GC retention times, partition coefficients and a subset of semiempirically derived energy terms. Important also were parameters reflecting differences in substitution patterns and related to electronic and steric properties, such as UV absorption in the wavelength region 245-300 nm, the barrier of internal rotation and the ionization potential. The developed model describes the large variation in physicochemical characteristics within the PCBs. The importance of a broad chemical characterization is illustrated by a quantitative structure-activity relationship (QSAR) for the potency of inhibition of intercellular communication for 27 structurally diverse tetra- to heptachlorinated PCBs.
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| 17. |
- Andersson, Patrik, et al.
(författare)
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Ultraviolet absorption spectra of all 209 polychlorinated biphenyls evaluated by principal component analysis
- 1997
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Ingår i: Fresenius' Journal of Analytical Chemistry. - : Springer Science and Business Media LLC. - 0937-0633 .- 1432-1130. ; 357:8, s. 1088-1092
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Tidskriftsartikel (refereegranskat)abstract
- The ultraviolet absorption spectra of all 209 polychlorinated biphenyls (PCBs) were recorded in the range 200-300 nm and displayed two important absorption maxima, viz., the main-band, lambda(max) 200-225 nm, and the kappa-band, lambda(max) 245-265 nm. By utilising principal component analysis, substitution related spectral characteristics of the PCBs, underlying the main patterns of the spectra, were examined. Captured in the multivariate evaluation were e.g., the importance of chlorine atoms in ortho positions, determining the intensity and existence of the kappa-band, chlorine substitution in para-para position, and the total number of chlorine atoms. The measured UV-spectra of all 209 polychlorinated biphenyls provide important physico-chemical descriptors for use in future quantitative structure-activity and structure-property relationship (QSAR/QSPR) studies.
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| 18. |
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| 19. |
- Antoniou, Maria G., et al.
(författare)
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Required ozone doses for removing pharmaceuticals from wastewater effluents
- 2013
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Ingår i: Science of the Total Environment. - Amsterdam : Elsevier BV. - 1879-1026 .- 0048-9697. ; 456, s. 42-49
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the this study was to investigate the ozone dosage required to remove active pharmaceutical ingredients (APIs) from biologically treated wastewater of varying quality, originated from different raw wastewater and wastewater treatment processes. Secondary effluents from six Swedish wastewater treatment plants (WWTP) were spiked with 42 APIs (nominal concentration 1 mu g/L) and treated with different O-3 doses (0.5-12.0 mg/L ozone) in bench-scale experiments. In order to compare the sensitivity of APIs in each matrix, the specific dose of ozone required to achieve reduction by one decade of each investigated API (DDO3) was determined for each effluent by fitting a first order equation to the remaining concentration of API at each applied ozone dose. Ozone dose requirements were found to vary significantly between effluents depending on their matrix characteristics. The specific ozone dose was then normalized to the dissolved organic carbon (DOC) of each effluent. The DDO3/DOC ratios were comparable for each API between the effluents. 15 of the 42 investigated APIs could be classified as easily degradable (DDO3/DOC <= 0.7), while 19 were moderately degradable (0.7 < DDO3/DOC <= 1.4), and 8 were recalcitrant towards O-3-treatment (DDO3/DOC > 1.4). Furthermore, we predict that a reasonable estimate of the ozone dose required to remove any of the investigated APIs may be attained by multiplying the experimental average DDO3/DOC obtained with the actual DOC of any effluent. (C) 2013 Elsevier B.V. All rights reserved.
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| 20. |
- Antoniou, Maria G., et al.
(författare)
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Variability in required ozone doses for removing pharmaceuticals from wastewater effluents
- 2013
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Ingår i: Proceedings of the 13th International Conference on Environmental Science and Technology. - : Global Nest, Secretariat. - 9789607475510
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Konferensbidrag (refereegranskat)abstract
- Aim of study. The aim of the present study was to investigate the ozone dosage required to remove active pharmaceutical ingredients (APIs) from biologically treated wastewater of varying quality originating from different wastewater treatment processes. Methods. Secondary effluents from six Swedish wastewater treatment plants (VWVTP) were spiked with 42 APIs (nominal concentration 1pg/L) and treated with different 03 doses (0.5-12.0 mg/L ozone) in bench-scale experiments (Antoniou et al, 2012). Concentrations of APIs were measured by SPE extraction using OASIS HLB cartridges followed by quantification using LC-MS-MS (Grabic et al, 2012).. Results. For each wastewater effluent a profile of sensitivity of each API to a range of ozone doses were generated as shown in Figure 1.
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