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- Åström, Mats E., 1963-, et al.
(författare)
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Sources, transport and sinks of beryllium in a coastal landscape affected by acidic soils
- 2018
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Ingår i: Geochimica et Cosmochimica Acta. - : Elsevier. - 0016-7037 .- 1872-9533. ; 232, s. 288-302
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Tidskriftsartikel (refereegranskat)abstract
- Beryllium (Be) sources, transport and sinks were studied in a coastal landscape where acidic soils (acid sulfate soils) have developed after drainage of fine-grained sulfide-bearing sediments. The study included the determination of total abundance and speciation of Be in a variety of solid and aqueous materials in both the terrestrial and estuarine parts of the landscape. A major feature was that despite normal (background) Be concentration in the sulfide-bearing sediments, the Be leaching from these sediments after O2-exposure and acid sulfate soil development were extensive, with concentrations up to 76 μg L−1 in soil water, 39 μg L−1 in runoff and 12 μg L−1 in low-order streams. These high Be concentrations were mainly in the solution form (i.e., passing a 1 kilodalton filter) and modelled to be dominated by free Be2+. The extensive Be release within, and leaching from the acid sulfate soils was controlled by pH, with a critical value of 4.0 below which the Be concentrations increased strongly. Although plagioclase and mica were most likely the main carriers of Be within these soils, it is suggested that other minerals such as Be hydroxides, Al hydroxides carrying Be, and Be sulfides are the main contributors of the abundance of dissolved Be in the acidic waters. When the acidic and Be-rich creek water was neutralized in the estuary of relatively low salinity, the dominating solution form of Be was removed by transformation to particles, reflected in the suspended particulate matter that had hydroxylamine hydrochloride extractable Be up to 17 mg kg−1 and ammonium acetate EDTA extractable Be up to 4 mg kg−1. In corresponding pristine materials (parent material of the acid sulfate soils) in the catchment, the median Be extractability with these reagents were only 0.3 and 0.05 mg kg−1, respectively. As the Be-rich suspended particulate matter ultimately became benthic sediment, the Be was preserved in terms of total concentrations but underwent to some extent changes in speciation, including release from hydroxides and concomitant scavenging by organic matter and particle surfaces.
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- Augustsson, Katarina, et al.
(författare)
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Assessment of the human exposure to heterocyclic amines
- 1997
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 18:10, s. 1931-1935
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Tidskriftsartikel (refereegranskat)abstract
- Heterocyclic amines are possible human carcinogens and fried meat is an important source of exposure in the Western diet, To study the effect of heterocyclic amines in humans, accurate assessment of individual food consumption is essential, Parameters influencing the intake include the amount and type of meat ingested, frequency of consumption, cooking method, cooking temperature and the duration of cooking, The aim of the present study was to develop a practical method for assessing individual intakes of specific heterocyclic amines in a large sample of people, This has been done by combining information on food consumption and laboratory findings of heterocyclic amines in food products, Diet was assessed using a semi-quantitative food frequency questionnaire including photos of fried meat and, in all, 22 dishes were cooked and chemically analyzed. The method was employed in an elderly population in Stockholm to estimate the daily mean intake of the five heterocyclic amines 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo [4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo [4,5-f]quinoxaline (DiMeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), The total daily intake ranged from none to 1816 ng, with a mean intake of 160 ng, which is well below estimates reported previously, Highest amounts ingested were of PhIP (mean 72, range 0-865 ng/day) and MeIQx (mean 72, range 0-1388 ng/day), followed by DiMeIQx (mean 16, range 0-171 ng/day), while MeIQ and IQ were ingested only in very small amounts (mean <1 ng/day).
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- Augustsson, Katarina, et al.
(författare)
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Dietary heterocyclic amines and cancer of the colon, rectum, bladder, and kidney : a population-based study
- 1999
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Ingår i: The Lancet. - 0140-6736 .- 1474-547X. ; 353:9154, s. 703-707
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Tidskriftsartikel (refereegranskat)abstract
- Background Heterocyclic amines formed in cooked meat and fish are carcinogenic in animal models and form DNA adducts in human beings. We undertook a study to assess whether these substances are related to the risks of cancer in the large bowel and urinary tract. Methods In a population-based case-control study, cases were identified from the Swedish cancer registry. Controls were randomly selected from the population register. Information on intake of various foods and was assessed by questionnaire, with photographs of foods cooked at various temperatures. We measured the content of heterocyclic amines in foods cooked under these conditions. Findings Information was retrieved from 553 controls, 352 cases of colon cancer, 249 cases of rectal cancer, 273 cases of bladder cancer, and 138 cases of kidney cancer. The response rate was 80% for controls and 70% for cases. The estimated daily median intake of heterocyclic amines was 77 ng for controls, and 66 ng, 63 ng, 96 ng, and 84 ng for cases with cancer of the colon, rectum, bladder, and kidney, respectively. The relative risk for the intake of heterocyclic amines (highest vs lowest quintile) was 0.6 (95% CI 0.4-1.0) for colon cancer, 0.7 (0.4-1.1) for rectal cancer, 1.2 (0.7-2.1) for bladder cancer, and 1.0 (0.5-1.9) for kidney cancer. Seven cases, but no controls, had an estimated daily intake of heterocyclic amines above 1900 ng. Interpretation Intake of heterocyclic amines, within the usual dietary range in this study population, is unlikely to increase the incidence of cancer in the colon, rectum, bladder, or kidney. For daily intakes above 1900 ng, our data are consistent with human carcinogenicity, but the precision was extremely low.
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- Augustsson, Per, et al.
(författare)
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Buffer medium exchange in continuous cell and particle streams using ultrasonic standing wave focusing
- 2009
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Ingår i: Microchimica Acta. - : Springer Science and Business Media LLC. - 1436-5073 .- 0026-3672. ; 164:3-4, s. 269-277
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Tidskriftsartikel (refereegranskat)abstract
- A microfluidic strategy to perform buffer exchange of particle and cell suspensions in a continuous flow format on, chip is presented. Ultrasonic standing wave technology is utilized to confine particulate matter to the centre of a buffer exchange channel while particle free buffer is sequentially aspirated via capillaries that branch off from the buffer exchange channel. At each such branch, clean buffer is supplied at an equal flow-rate from a capillary at the opposing channel wall, generating a sideways translation of the original buffer, laminated with a wash buffer stream. Each such junction increases the buffer exchange ratio accordingly. The reported buffer exchange system provides means to adjust buffer exchange conditions on-line by tuning the ratio of the cross-flow wash buffer relative the sample suspension flow, rate. The system performance was evaluated using 5 mu m polystyrene microbeads and a dye as the model contaminant. Wash efficiencies up to 96.4% were accomplished with a 0.2% solid content bead suspension, using eight cross-flow junctions, effectively exchanging the carrier buffer twice. The corresponding data for erythrocyte washing was recorded to be 98.3% at a haematocrit of 2%.
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