Found: 7010 publications , showing page 333 of 585
Scientific paper
Microemulsion electrokinetic chromatography of drugs varying in charge and hydrophobicity: I. Impact of parameters on separation performance evaluated by multiple linear regression models
Harang, Valerie, Eriksson, Jessica, Saenger-van de Griend, Cari E, S P. Jacobsson
2004
| 25(1)
(80-93)
The separation of anionic, cationic and neutral drugs in microemulsion electrokinetic chromatography (MEEKC) was studied with a statistical experimental design. The concentration of sodium dodecyl sulfate (SDS, surfactant), 1-butanol (co-surfactant) and borate buffer and the factors Brij 35 (surfactant), 2-propanol (organic solvent) and cassette temperature were varied simultaneously, while the parameters pH (9.2), the concentration of octane (oil, 0.8% w/w), the voltage (10 kV) and the dimension of the fused-silica capillary, were kept constant. Eight different model substances were chosen with different hydrophobicities. Two of the analytes were positively charged, two were negatively charged, and the remaining four were neutral or close to neutral at the pH explored. The importance of each parameter on the separation window, the plate height and the retention factor for each of the analytes was studied by means of multiple linear regression (MLR) models. A new response was evaluated for anions, the quotient between the effective mobility in the microemulsion and the effective mobility in the corresponding buffer. Factors affecting selectivity changes were also explored, and it was found that SDS and 2-propanol had the largest effect on selectivity.
Presentation abstract
Variations in colloidal carrier phases and size fractionation associated with the rare earth elements in a boreal river.
Dahlqvist, R.; Ingri, J.; Andersson, P.
2004
| Geochim. Cosmochim. Acta
| 68
14th Annual V. M. Goldschmidt conference
Scientific paper
Latitudinal fractionation of polychlorinated biphenyls in surface seawater along a &?N- 89N transect from the southern Norwegian Sea to the North Pole area.
Sobek, A.; Gustafsson, Ö.
2004
| Environ. Sci. Technol.
| 38
Scientific paper
Some brominated diphenyl ether (PBDE) flame retardants with wide environmental distribution inhibit TCDD-iduced EROD activity in primary cultured carp (Cyprinus carpio) hepatocytes
Kuiper RV; Bergman Å; Vos JG; van den Berg M;
2004
| Aquat. Toxicol.
| 68
Technical report
Mätningar och beräkningar av påverkan på luftföroreningshalter, del 1 Lycksele.
Johansson, C.; Hedberg, E.; Olivares, G.; Gidhagen, L.; Karlsson, H.; Wideqvist, U.; Vesely, V.; E. Swietlicki, A. Kristensson; J. Zhou, J. Rissler; P. Brohammer, E. Brorström-Lundén; K. Peterson, M. Remberger; A. Potter, E. Junedahl; K. Persson, K. Sjöberg; E. Sellin-Lindgren, J. Jacobsson; C. Tranefors, L. Andersson; E. Eltahir, G. Omstedt; J. Langner, V Foltescu; M. Pettersson, R. Ahlinder; B. Sjövall, B. Norberg
Twelfth International Symposium on Pollutant Responses in Marine Organisms (PRIMO 12)
| April 27, 2024
| Safety Harbor, FL, USA
Bottom sediment in the bay Örserumsviken, Swedish coast, is highly contaminated by PCBs. Previous investigations have shown that PCBs are not the only factor regarding CYP1A induction, fish larvae deformations and mortality. Three fractions mainly composed of aliphatic/monocyclic aromatic compounds (MAC), dicyclic aromatic compounds (DAC) and polycyclic aromatic compounds (PAC) were isolated from an organic extract of the bottom sediment. By using the nanoinjection technique, the fractions were exposed to newly fertilized Oncorhyncus mykiss eggs. Deformations were recorded at hatch, and at 2/3 of yolk consumption, CYP1A activities were measured in larval livers. As expected, the PCB content in the bottom sediment explained the CYP1A induction of the DAC-fraction. Beside the similar CYP1A induction, the PAC-fraction was more potent than the DAC-fraction regarding deformations and mortality. Consequently, it was fractionated into ten sub-fractions. A synthetic PAC-fraction composed of 18 PAHs were prepared as well as fractionated, identical to the PAC-fraction. All ten sub-fractions of the PAC-fraction caused CYP1A induction. Moreover, two sub-fractions caused high numbers of deformations and one deformation was isolated through the fractionation steps. However, the synthetic PAC-fraction, and thus the 18 PAHs, could only to a limited degree induce the adverse effects. High levels of PAHs substituted with alkyl as well as sulfur groups with unknown toxic potential were observed in the PAC-fraction by using HRGC/MS analysis. In conclusion, by utilizing a biomarker-directed fractionation approach, other chemicals than well studied PCBs and PAHs, have proven to have potential to induce adverse effects in this area.
Scientific paper
Monthly averaged ozone and nitrous oxide from the Improved Limb Atmospheric Spectrometer (ILAS) in the Northern and Southern Hemisphere polar regions
Khosrawi, F.; Mueller, R.; Proffitt, M.H.; Nakajima, H.
2004
| J. Geophys. Res.
| 109
Scientific paper
NMR solution structure and position of transportan in neutral phospholipid bicelles
Barany-Wallje, E; Andersson, A; Graslund, A; Maler, L
2004
| FEBS Lett.
| 567
(2-3)
(265-269)
Scientific paper
Speciation and origin of PM10 and PM2.5 in selected European cities
PM characteristics of seven selected regions within the European Union (EU) were analysed and compared. Results of levels and speciation studies of PM10 and PM2.5 (with at least one year of data coverage from 1998 to 2002) at regional, urban background and kerbside sites were assessed. Based on the examples selected, PM10 levels (annual mean) ranged from 19 to 24 mug m(-3) at regional background sites, from 28 to 42 mug m(-3) at urban background, and from 37 to 53 mug m(-3) at kerbside sites. PM2.5 levels varied from 8 to 20 mug m(-3) at regional background sites, 20 to 30 mug m(-3) at urban background and 25 to 40 mug m(-3) at kerbside sites. The ratio PM2.5/PM10 is highly dependent on the type of site and varied widely between different EU regions. Source apportionment results showed that, on an annual average, the natural contribution (mineral and marine) at EU regional sites was in the range of 4-8 mug m(-3) in PM10 decreasing in PM2.5, but contributions up to 19 mug m(-3) were reported for specific locations. At urban sites, carbonaceous aerosols and secondary inorganic compounds accounted for a major fraction of PM10, and especially of the PM2.5 mass. Quantitative data on the contributions of the regional background, city background and local traffic to the mean annual levels of PM10, PM2.5 and major components were supplied. Climatic differences, long-range transport processes and winter traffic peculiarities (the latter in northern countries) contributed to the increase of PM10 and PM2.5 masses. At kerbside sites, an important dust contribution to PM2.5 is highlighted. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific paper
Polychlorinated naphthalenes in Swedish Background air.
Egebäck, A-L.; Wideqvist, U.; Järnberg, U.; Asplund, L.
2004
| Environ. Sci. Technol.
| 38
(4913-4920)
Technical report
POP Model Intercomparison Study, Stage I. Comparison of descriptions of main processes determining POP behaviour in various environmental compartments.
Baart, A.; Bartlett, P.; Breivik, K.; Christensen, J.H.; Dutchak, S.; Kallweit, D.; Farret, R.; Fedyunin, M.; Gong, S.; Hansen, K.M.; Holoubek, I.; Huang, P.; Jones, K.C.; Mantseva, E.; Matthies, M.; Petersen, G.; Prevedouros, K.; Pudykiewicz, J.; Roemer, M.; Salzmann, M.; Sheringer, M.; Shatalov, V.; Stocker, J.; Strukov, B.; Suzuki, N.; Sweetman, A.J.; van de Meent, D.; Wegmann, F.
2004
| EMEP
Presentation abstract
Observations on the quantitative links between PBDE uses, emissions and environmental measurements in Europe
