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- Abrahamsson, Christina, et al.
(författare)
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DeltaT50 - a new method to assess temporal ventricular repolarization variability
- 2011
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 44:4
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Tidskriftsartikel (refereegranskat)abstract
- Background Increased beat-to-beat variability in cardiac repolarization time is a tentative risk marker of drug-induced torsades de pointes. We developed a new, automatic method based on the temporal variability of the T-wave down slope to assess this variability. Method and Results Leads V1 to V6 of resting electrocardiograms were recorded in 42 healthy subjects (18-68 years, 22 men). The temporal variability at 50% of the T-wave down slope, deltaT50 (1.5 ± 0.41 milliseconds; range, 0.86-2.66 milliseconds), was measured with an accuracy of 1 millisecond on at least 9 pairs of electrocardiogram complexes with a signal-to-noise ratio more than 10 and changes in the R-R interval less than 150 milliseconds. The correlation between repeated measurements of deltaT50 was high. DeltaT50 was measured without corrections for age, sex, heart rate, T-wave amplitude, signal-to-noise ratio, R-R variability, and QTcF because none of these factors explained more than 4% of the within-subject deltaT50 variability. Conclusion The beat-to-beat repolarization variability was measured with high fidelity with the deltaT50 method and was a robust measure in healthy volunteers.
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| 5. |
- Düker, Anders, 1966-
(författare)
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Natural aquatic colloidal matter : Characteristics and impact on the mobility of trace metals and organics
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Natural colloidal (< 1.0 µm) matter plays an important role for tbe transport and redistribution of water-borne substances. The aim of this work was to characterise colloidal matter from surface waters and groundwaters, and to improve on the understanding on the role of natural colloidal matter in the redistribution and mobility of trace metals. Laboratory studies of tbe stability (coagulation rate) of model colloids showed that the stability was dependent on the electrolyte composition, pH and the presence of fulvic acid. The uptake of Zn(II) and Pb(II) on colloidal AI, Fe, and Si (hydr)oxides was studied at high and low concentrations of reactants. The concentration of fulvic acid, pH, and thecomposition of the solid phase had a strong influence on the interaction between the metal ions and the solid surfaces. Photon correlation spectroscopy was used for measurements of particle size distributions in surface water and groundwater, and was also found to be suitable for on-line measurements in samples sensitive to changes in the partial pressure of atmospheric gases. The intensity of the scattered light was found to be useful for simultaneous estimates of tbe colloidal particle concentration. A calibration of the light intensity with material from one sample site showed that the spatial variation in sensitivity within a small catchment was relatively large, and there was also a variation in time. The mechanisms behind the concentration and composition of colloids were complex, but were to some extent related to input of organic carbon, pH aluminium and iron. Studies of colloidal matter in an estuary and a saline groundwater demonstrated the coagulating effect of high ionic strength and the presence of divalent ions. The major part of manganese and organic carbon was not bound in colloidal particles in the freshwater and estuarine samples, in contrast to aluminium and iron.
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| 6. |
- Elgh-Dalgren, Kristin, et al.
(författare)
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Anaerobic bioremediation of a soil with mixed contaminants : Explosives degradation and influence on heavy metal distribution, monitored as changes in concentration and toxicity
- 2009
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Ingår i: Water, Air and Soil Pollution. - Dordrecht : Springer Netherlands. - 0049-6979 .- 1573-2932. ; 202:1-4, s. 301-313
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Tidskriftsartikel (refereegranskat)abstract
- Two soils with explosives and metals were evaluated for the degradation efficiency of explosives by native microorganisms under anaerobic conditions. The commercially available method Daramend®, amended with zero-valent iron (ZVI), was compared with a horse-manure amended compost and a treatment with ZVI alone. In a moderately contaminated soil, Daramend® and ZVI treatment gave significantly higher removal rates compared to compost and control treatments (Tukey’s test, P<0.05). The largest overall decrease in ecotoxicity, measured with bioluminescent bacteria (Vibrio fischeri), was achieved with ZVI-treatment. In a more contaminated soil no degradation of contaminants and no decline in soil toxicity could be distinguished after the same time period. Problems with establishment of anaerobic conditions during parts of the remediation process and low microbial activity due to acute toxicity of contaminants are plausible explanations. Redistribution that could potentially lead to mobilization of the co-contaminant Pb was not observed in either of the soils during the biological treatments.
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| 7. |
- Elgh-Dalgren, Kristin, et al.
(författare)
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Re-cycling of remediated soil : evaluation of leaching tests as tools for characterization
- 2011
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Ingår i: Waste Management. - : Pergamon Press. - 0956-053X .- 1879-2456. ; 31:2, s. 215-224
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Tidskriftsartikel (refereegranskat)abstract
- In Sweden, leaching tests with deionized water (D.W.) are frequently utilized in risk assessment, but implementation of these results to evaluate the risk of spreading in the environment is difficult. One problem is that most leaching procedures only consider heavy metals release, whereas organic pollutants are left out. The aim of the present study was to assess the possible pollutant mitigation in four remediated soils, three with heavy metals and one with polycyclic aromatic hydrocarbons (PAH), utilizing three different leaching solutions: D.W., a weak ionic solution (0.001 M CaCl2) and an artificially made soil water (ASW). In general, batch leaching implied larger contaminant removal than column leaching, possibly due to the more rough treatment of the soil particles, and guidelines would at times be exceeded by batch leaching but not column leaching. Utilization of CaCl2 was found to release much less heavy metal than D.W., whereas the metals mobilized by ASW were removed from solution by the filtration of soil leachates. Low molecular weight PAH was most efficiently mobilized by CaCl2, while D.W. worked better for high molecular weight PAH. Despite very low initial PAH-concentrations, tap- and groundwater criteria were exceeded by all leaching solutions.
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| 8. |
- Elgh-Dalgren, Kristin, 1980-, et al.
(författare)
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Simultaneous remediation of explosives and lead from contaminated soil by pH-adjustment
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Soil washing with pH-adjusted water was evaluated in two soils containing different concentrations of heavy metals and explosives. Overall, the most efficient treatment was with water adjusted to pH 12 by NaOH. For explosives, pH 12 removed significantly higher amounts (P<0.05) of RDX and TNT compared to pH 4 (adjusted with HNO3) and distilled water in a moderately contaminated soil (230 mg HMX/kg, 1340 mg RDX/kg, 450 mg TNT/kg). In a more highly contaminated soil (6080 mg HMX/kg, 28740 mg RDX/kg, 3120 mg TNT/kg), the pH 12-treatment was the most efficient for removal of TNT and 2,4-DNT. Explosives removal increased with treatment time, probably due to the kinetically slow processes underlying the explosives degradation. Mobilization of heavy metals was strongly dependent on pH, with pH 12 mobilizing more than pH 3. In addition, the change in distribution coefficient (Kd) was more pronounced for local contaminants Pb and Cd in comparison with Cu and Zn, which were present in background concentrations.
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