| 1. |
- Eriksson, Olof, et al.
(författare)
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The Positron Emission Tomography ligand [11C]5-Hydroxy-Tryptophan can be used as a surrogate marker for the human endocrine pancreas
- 2014
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 63:10, s. 3428-3437
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Tidskriftsartikel (refereegranskat)abstract
- In humans a well-developed serotonin system is localized to the pancreatic islets while being absent in exocrine pancreas. Assessment of pancreatic serotonin biosynthesis could therefore be used to estimate the human endocrine pancreas. Proof of concept was tested in a prospective clinical trial by comparisons of type 1 diabetic (T1D) patients, with extensive reduction of beta cells, with healthy volunteers (HV).C-peptide negative (i.e. insulin-deficient) T1D subjects (n=10) and HV (n=9) underwent dynamic Positron Emission Tomography with the radiolabeled serotonin precursor [(11)C]5-Hydroxy-Tryptophan ([(11)C]5-HTP).A significant accumulation of [(11)C]5-HTP was obtained in the pancreas of the HV, with large inter-individual variation. A substantial and highly significant reduction (66%) in the pancreatic uptake of [(11)C]5-HTP in T1D subjects was observed, and this was most evident in the corpus and caudal regions of the pancreas where beta-cells normally are the major constituent of the islets.[(11)C]5-HTP retention in the pancreas was reduced in T1D compared to non-diabetic subjects. Accumulation of [(11)C]5-HTP in the pancreas of both HV and subjects with T1D were in agreement with previously reported morphological observations on the beta cell volume implying that [(11)C]5-HTP retention is a useful non-invasive surrogate marker for the human endocrine pancreas.
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| 2. |
- Callaghan, Terry, et al.
(författare)
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Multi-Decadal Changes in Tundra Environments and Ecosystems : Synthesis of the International Polar Year-Back to the Future Project (IPY-BTF)
- 2011
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 40:6, s. 705-716
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the responses of tundra systemsto global change has global implications. Most tundraregions lack sustained environmental monitoring and oneof the only ways to document multi-decadal change is toresample historic research sites. The International PolarYear (IPY) provided a unique opportunity for such researchthrough the Back to the Future (BTF) project (IPY project#512). This article synthesizes the results from 13 paperswithin this Ambio Special Issue. Abiotic changes includeglacial recession in the Altai Mountains, Russia; increasedsnow depth and hardness, permafrost warming, andincreased growing season length in sub-arctic Sweden;drying of ponds in Greenland; increased nutrient availabilityin Alaskan tundra ponds, and warming at mostlocations studied. Biotic changes ranged from relativelyminor plant community change at two sites in Greenland tomoderate change in the Yukon, and to dramatic increasesin shrub and tree density on Herschel Island, and in subarcticSweden. The population of geese tripled at one sitein northeast Greenland where biomass in non-grazed plotsdoubled. A model parameterized using results from a BTFstudy forecasts substantial declines in all snowbeds andincreases in shrub tundra on Niwot Ridge, Colorado overthe next century. In general, results support and provideimproved capacities for validating experimental manipulation,remote sensing, and modeling studies.
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| 3. |
- Israelsson, Axel
(författare)
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Chewing gum and human hair as retrospective dosimeters
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Retrospective dosimeters are sometimes needed after radiological/nuclear (RN) exposures to determine the doses to individuals. Conventional dosimeters may not be at hand or may not be applicable calling for alternative materials.The possible exposure situations can be divided into external and internal; the radiation field stems either from outside the body or from a source within. This thesis investigates the possibility to use chewing gum and hair as retrospective dosimeters. The chewing gum would be used after an unexpected radiation event of external type whereas human hair is examined after chronic intake of uranium. Chewing gum containing xylitol and sorbitol was analyzed using electron paramagnetic resonance (EPR) and the hair was analyzed by alphaspectrometry following radiochemistry and by synchrotron radiation microbeam x-ray fluorescence (SR μ-XRF).Xylitol and chewing gum (in this particular case, V6) are in the present work found to be valuable dosimeters after unexpected radiation events. The xylitol signal linearity with dose in the interval 0-10 Gy was confirmed (r2=1.00). The doses to the coating of the chewing gums were determined 4-6 days after irradiation with an uncertainty of less than 0.2 Gy (1 SD). Spectral dependence with time after exposure was found, but was, however, minimal between 4-8 days.Hair was evaluated and compared with urine as biodosimeter after ingestion and inhalation intake of uranium. Concentrations of 234U and 238U and their activity ratios were measured in the hair, urine and drinking water sampled from 24 drilled bedrock well water users in Östergötland, Sweden, as well as among 8 workers at a nuclear fuel fabrication factory, Westinghouse Electric Sweden. The results show that there is a stronger correlation between the uranium concentrations in the drinking water of the well water and the users’ hair (r2 = 0.50) than with their urine (r2 = 0.21). There is also a stronger correlation between the 234U/238U activity ratios of water and hair (r2 = 0.91) than between water and urine (r2 = 0.56). The individual absorbed fraction of uranium, the ƒ value, calculated as the ratio between the excreted amount of uranium in urine and hair per day and the daily drinking water intake of uranium stretched from 0.002 to 0.10 with a median of 0.023. The uranium concentrations of the fuel factory workers’ hair and urine were also obtained as well as that of personal air sampler (PAS) filters for the determination of inhaled uranium activity. A large day-to-day variation (7-70 Bq d-1) of the inhaled 234U activity was seen over a 6 week period. Over a 12 week period the 234U activity concentration in urine was similarly seen to vary from 2 to 50 mBq kg-1. Four hair samples from the same subject and period showed less variation (100-240 mBq g-1). The uranium inhalation to urine and hair factors finh,u and finh,h were found to be 0.0014 and 0.0002 respectively given by calculations based on the measured PAS, urine and hair data from two individuals. The SR μ-XRF measurements showed that uranium is present in an outer layer of the hair shaft, about 10-15 μm wide. The measurements also revealed particles containing uranium being present on the surface of unwashed hair shafts. However, the washed hair shafts showed few, if any, particles.This thesis concludes that chewing gum and hair can be used as retrospective dosimeters after external radiation and after intake of uranium respectively.
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| 4. |
- Malmgren, Christine, et al.
(författare)
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Nanocrystallinity in RuO2 coatings-Influence of precursor and preparation temperature
- 2010
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 518:14, s. 3615-3618
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Tidskriftsartikel (refereegranskat)abstract
- The effects of precursor and calcination temperature on the nano morphology of ruthenium dioxide on titanium, prepared from thermal decomposition of aqueous salt solutions were investigated. Transmission electron microscopy. X-ray diffraction, gas porosimetry and cyclic voltammetry showed that lower calcination temperature yielded smaller crystallites. The crystallites were between 6 and 22 nm in diameter. When using ruthenium nitrosyl nitrate the firing temperature had a large impact on the grain size, but for chloride there was only a minor effect in the temperature range 350-550 degrees C.
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| 5. |
- Vimaleswaran, Karani S, et al.
(författare)
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Association of vitamin D status with arterial blood pressure and hypertension risk: a mendelian randomisation study.
- 2014
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Ingår i: The lancet. Diabetes & endocrinology. - 2213-8595 .- 2213-8587. ; 2:9, s. 719-29
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Tidskriftsartikel (refereegranskat)abstract
- Background Low plasma 25-hydroxyvitamin D (25[OH]D) concentration is associated with high arterial blood pressure and hypertension risk, but whether this association is causal is unknown. We used a mendelian randomisation approach to test whether 25(OH)D concentration is causally associated with blood pressure and hypertension risk. Methods In this mendelian randomisation study, we generated an allele score (25[OH]D synthesis score) based on variants of genes that affect 25(OH)D synthesis or substrate availability (CYP2R1 and DHCR7), which we used as a proxy for 25(OH)D concentration. We meta-analysed data for up to 108173 individuals from 35 studies in the D-CarDia collaboration to investigate associations between the allele score and blood pressure measurements. We complemented these analyses with previously published summary statistics from the International Consortium on Blood Pressure (ICBP), the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium, and the Global Blood Pressure Genetics (Global BPGen) consortium. Findings In phenotypic analyses (up to n=49363), increased 25(OH)D concentration was associated with decreased systolic blood pressure (β per 10% increase, −0·12 mm Hg, 95% CI −0·20 to −0·04; p=0·003) and reduced odds of hypertension (odds ratio [OR] 0·98, 95% CI 0·97–0·99; p=0·0003), but not with decreased diastolic blood pressure (β per 10% increase, −0·02 mm Hg, −0·08 to 0·03; p=0·37). In meta-analyses in which we combined data from D-CarDia and the ICBP (n=146581, after exclusion of overlapping studies), each 25(OH)D-increasing allele of the synthesis score was associated with a change of −0·10 mm Hg in systolic blood pressure (−0·21 to −0·0001; p=0·0498) and a change of −0·08 mm Hg in diastolic blood pressure (−0·15 to −0·02; p=0·01). When D-CarDia and consortia data for hypertension were meta-analysed together (n=142255), the synthesis score was associated with a reduced odds of hypertension (OR per allele, 0·98, 0·96–0·99; p=0·001). In instrumental variable analysis, each 10% increase in genetically instrumented 25(OH)D concentration was associated with a change of −0·29 mm Hg in diastolic blood pressure (−0·52 to −0·07; p=0·01), a change of −0·37 mm Hg in systolic blood pressure (−0·73 to 0·003; p=0·052), and an 8·1% decreased odds of hypertension (OR 0·92, 0·87–0·97; p=0·002). Interpretation Increased plasma concentrations of 25(OH)D might reduce the risk of hypertension. This finding warrants further investigation in an independent, similarly powered study.
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| 6. |
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| 7. |
- Andersson, Linda, et al.
(författare)
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Myeloid blood dendritic cells and monocyte-derived dendritic cells differ in their endocytosing capability
- 2012
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Ingår i: Human Immunology. - : Elsevier. - 0198-8859 .- 1879-1166. ; 73:11, s. 1073-1081
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Tidskriftsartikel (refereegranskat)abstract
- Human dendritic cells (DCs) constitute a heterogeneous population of antigen-presenting cells characterized by a unique capacity to stimulate naive T cells. The functions of DCs depend on the particular subset and in this study we compare two types of myeloid DCs: freshly isolated blood mDCs and in vitro generated monocyte-derived DCs (MoDCs), in their ability to accomplish endocytosis. In our hands, these two DC subtypes showed similarities in the expression of surface markers, but displayed clear differences in endocytic capacity. Freshly isolated blood mDCs showed a high propensity to capture and endocytose particles compared to in vitro generated MoDCs. The blood mDCs also showed a clear receptor-enhanced endocytosis when zeolite particles were co-adsorbed with IgG. On the other hand, the MoDCs differed remarkably compared to blood mDCs in the capture of ovalbumin and immune complexes. Interestingly, the MoDCs showed low endocytosis of IgG-coated particles but an efficient capture of immune complexes. The MoDCs also showed a high capacity to capture ovalbumin although with a relatively low degree of internalization. These data indicate distinct differences in the early process of endocytosis featured by mDCs and MoDCs, which is important to consider when choosing DC populations for future functional or clinical applications.
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| 8. |
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| 9. |
- Axelsson, Sara, 1975-
(författare)
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Resin acids in commercial products and the work environment of Swedish wood pellets production : Analytical methodology, occurrence and exposure
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aims of the work this thesis is based upon were to develop convenient analytical procedures for determining resin acids in biological and environmental matrices, and apply them to enhance understanding of the occurrence, exposure to and uptake by exposed individuals of resin acids. Particular focus has been on the workplace environment of the Swedish wood pellets industry. Sample extraction procedures and high-performance liquid chromatography/electrospray ionisation-mass spectrometry (HPLC/ESI-MS) methodologies were developed for measuring resin acids in dust, skin and urine samples. Chromatographic separation of abietic (AA) and pimaric acid was achieved by using a polar-embedded C12 stationary phase. The HPLC/ESI-MS method avoids undesirable oxidation of AA, which was found to occur during the derivatisation step in the standard MDHS 83/2 gas chromatography/flame ionisation detection (GC/FID) methodology, leading to false observations of both AA and the oxidation product 7-oxodehydroabietic acid (7-OXO). Personal exposures to resin acids in the Swedish wood pellet production industry were found to be lower, on average, than the British Occupational Exposure Limit for rosin (50 µg/m3). The oxidised resin acid 7-OXO, was detected in both dust and skin samples indicating the presence of allergenic resin acids. A correlation between air and post-shift urinary concentrations of dehydroabietic acid (DHAA), and a trend towards an increase in urinary 7-OXO during work shifts, were also observed. Whether the increase in 7-OXO was due to direct uptake or metabolism of other resin acids cannot be concluded from the results. An efficient HPLC/UV methodology with diode-array detection was developed for screening commercial products for rosin that could be used in laboratories lacking mass spectrometers. Very high concentrations of free resin acids were detected in depilatory wax strips using the method.
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| 10. |
- Bengtsson, Fredrik, et al.
(författare)
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Sustainability Impact of Open Innovation Software
- 2012
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Ingår i: Proceedings of the XXIII ISPIM Conference Action for Innovation: Innovating from Experience, Barcelona, Spain, 17-20 June 2012..
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Konferensbidrag (refereegranskat)
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