| 1. |
- Abate, E., et al.
(författare)
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Combined performance tests before installation of the ATLAS Semiconductor and Transition Radiation Tracking Detectors
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS (A Toroidal LHC ApparatuS) Inner Detector provides charged particle tracking in the centre of the ATLAS experiment at the Large Hadron Collider (LHC). The Inner Detector consists of three subdetectors: the Pixel Detector, the Semiconductor Tracker (SCT), and the Transition Radiation Tracker (TRT). This paper summarizes the tests that were carried out at the final stage of SCT+TRT integration prior to their installation in ATLAS. The combined operation and performance of the SCT and TRT barrel and endcap detectors was investigated through a series of noise tests, and by recording the tracks of cosmic rays. This was a crucial test of hardware and software of the combined tracker detector systems. The results of noise and cross-talk tests on the SCT and TRT in their final assembled configuration, using final readout and supply hardware and software, are reported. The reconstruction and analysis of the recorded cosmic tracks allowed testing of the offline analysis chain and verification of basic tracker performance parameters, such as efficiency and spatial resolution, in combined operation before installation.
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| 2. |
- Abat, E., et al.
(författare)
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Study of the response of the ATLAS central calorimeter to pions of energies from 3 to 9 GeV
- 2009
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002 .- 1872-9576. ; 607:2, s. 372-386
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Tidskriftsartikel (refereegranskat)abstract
- A fully instrumented slice of the ATLAS central detector was exposed to test beams from the SPS (Super Proton Synchrotron) at CERN in 2004. in this paper, the response of the central calorimeters to pions with energies in the range between 3 and 9 GeV is presented. The linearity and the resolution of the combined calorimetry (electromagnetic and hadronic calorimeters) was measured and compared to the prediction of a detector simulation program using the toolkit Geant 4. (C) 2009 Elsevier B.V. All rights reserved.
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| 3. |
- Abat, E., et al.
(författare)
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The ATLAS TRT end-cap detectors
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS TRT end-cap is a tracking drift chamber using 245,760 individual tubular drift tubes. It is a part of the TRT tracker which consist of the barrel and two end-caps. The TRT end-caps cover the forward and backward pseudo-rapidity region 1.0 < vertical bar eta vertical bar < 2.0, while the TRT barrel central eta region vertical bar eta vertical bar < 1.0. The TRT system provides a combination of continuous tracking with many measurements in individual drift tubes ( or straws) and of electron identification based on transition radiation from fibers or foils interleaved between the straws themselves. Along with other two sub-systems, namely the Pixel detector and Semi Conductor Tracker (SCT), the TRT constitutes the ATLAS Inner Detector. This paper describes the recently completed and installed TRT end-cap detectors, their design, assembly, integration and the acceptance tests applied during the construction.
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| 4. |
- Abat, E., et al.
(författare)
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The ATLAS Transition Radiation Tracker (TRT) proportional drift tube: design and performance
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3:2
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Tidskriftsartikel (refereegranskat)abstract
- A straw proportional counter is the basic element of the ATLAS Transition Radiation Tracker (TRT). Its detailed properties as well as the main properties of a few TRT operating gas mixtures are described. Particular attention is paid to straw tube performance in high radiation conditions and to its operational stability.
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| 5. |
- Abat, E., et al.
(författare)
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The ATLAS TRT barrel detector
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3
-
Tidskriftsartikel (refereegranskat)abstract
- The ATLAS TRT barrel is a tracking drift chamber using 52,544 individual tubular drift tubes. It is one part of the ATLAS Inner Detector, which consists of three sub-systems: the pixel detector spanning the radius range 4 to 20 cm, the semiconductor tracker (SCT) from 30 to 52 cm, and the transition radiation tracker ( TRT) from 56 to 108 cm. The TRT barrel covers the central pseudo-rapidity region |eta| < 1, while the TRT endcaps cover the forward and backward eta regions. These TRT systems provide a combination of continuous tracking with many measurements in individual drift tubes ( or straws) and of electron identification based on transition radiation from fibers or foils interleaved between the straws themselves. This paper describes the recently-completed construction of the TRT Barrel detector, including the quality control procedures used in the fabrication of the detector.
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| 6. |
- Abat, E., et al.
(författare)
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The ATLAS TRT electronics
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3:6
-
Tidskriftsartikel (refereegranskat)abstract
- The ATLAS inner detector consists of three sub-systems: the pixel detector spanning the radius range 4cm-20cm, the semiconductor tracker at radii from 30 to 52 cm, and the transition radiation tracker (TRT), tracking from 56 to 107 cm. The TRT provides a combination of continuous tracking with many projective measurements based on individual drift tubes (or straws) and of electron identification based on transition radiation from fibres or foils interleaved between the straws themselves. This paper describes the on and off detector electronics for the TRT as well as the TRT portion of the data acquisition (DAQ) system.
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| 7. |
- Cwetanski, P, et al.
(författare)
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Acceptance tests and criteria of the ATLAS transition radiation tracker
- 2005
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Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499. ; 52:6, s. 2911-2916
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Tidskriftsartikel (refereegranskat)abstract
- The Transition Radiation Tracker (TRT) sits at the outermost part of the ATLAS Inner Detector, encasing the Pixel Detector and the Semi-Conductor Tracker (SCT). The TRT combines charged particle track reconstruction with electron identification capability. This is achieved by layers of xenonfilled straw tubes with periodic radiator foils or fibers providing TR photon emission. The design and choice of materials have been optimized to cope with the harsh operating conditions at the LHC, which are expected to lead to an accumulated radiation dose of 10 Mrad and a neutron fluence of up to 2 . 10(14) n/cm(2) after ten years of operation. The TRT comprises a barrel containing 52 000 axial straws and two end-cap parts with 320 000 radial straws. The total of 420 000 electronic channels (two channels per barrel straw) allows continuous tracking with many projective measurements (more than 30 straw hits per track). The assembly of the barrel modules in the US has recently been completed, while the end-cap wheel construction in Russia has reached the 50% mark. After testing at the production sites and shipment to CERN, all modules and wheels undergo a series of quality and conformity measurements. These acceptance tests survey dimensions, wire tension, gas-tightness, high-voltage stability and gas-gain uniformity along each individual straw. This paper gives details on the acceptance criteria and measurement methods. An overview of the most important results obtained to-date is also given.
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| 8. |
- Tjonneland, A., et al.
(författare)
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Linoleic acid, a dietary n-6 polyunsaturated fatty acid, and the aetiology of ulcerative colitis: a nested case-control study within a European prospective cohort study
- 2009
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Ingår i: Gut. - : BMJ. - 1468-3288 .- 0017-5749. ; 58:12, s. 1606-1611
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Dietary linoleic acid, an n-6 polyunsaturated fatty acid, is metabolised to arachidonic acid, a component of colonocyte membranes. Metabolites of arachidonic acid have pro-inflammatory properties and are increased in the mucosa of patients with ulcerative colitis. The aim of this investigation was to conduct the first prospective cohort study investigating if a high dietary intake of linoleic acid increases the risk of developing incident ulcerative colitis. Design and setting: Dietary data from food frequency questionnaires were available for 203 193 men and women aged 30-74 years, resident in the UK, Sweden, Denmark, Germany or Italy and participating in a prospective cohort study, the European Prospective Investigation into Cancer and Nutrition (EPIC). These participants were followed up for the diagnosis of ulcerative colitis. Each case was matched with four controls and the risk of disease calculated by quartile of intake of linoleic acid adjusted for gender, age, smoking, total energy intake and centre. Results: A total of 126 participants developed ulcerative colitis (47% women) after a median follow-up of 4.0 years (range, 1.7-11.3 years). The highest quartile of intake of linoleic acid was associated with an increased risk of ulcerative colitis (odds ratio (OR) = 2.49, 95% confidence interval (CI) = 1.23 to 5.07, p = 0.01) with a significant trend across quartiles (OR = 1.32 per quartile increase, 95% CI = 1.04 to 1.66, p = 0.02 for trend). Conclusions: The data support a role for dietary linoleic acid in the aetiology of ulcerative colitis. An estimated 30% of cases could be attributed to having dietary intakes higher than the lowest quartile of linoleic acid intake.
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| 9. |
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| 10. |
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| 11. |
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| 12. |
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| 13. |
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| 14. |
- Danielsson, J, et al.
(författare)
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15N relaxation study of the amyloid beta-peptide structural propensities and persistence length.
- 2006
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Ingår i: Magn Reson Chem. - : Wiley. - 0749-1581. ; 44:S1, s. S114-21
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Tidskriftsartikel (refereegranskat)abstract
- The dynamics of monomeric Alzheimer A(1-40) in aqueous solution was studied using heteronuclear NMR experiments. 15N NMR relaxation rates of amide groups report on the dynamics in the peptide chain and make it possible to estimate structural propensities from temperature-dependent relaxation data and chemical shifts change analysis. The persistence length of the polypeptide chain was determined using a model in which the influence of neighboring residue relaxation is assumed to decay exponentially as a function of distance. The persistence length of the A(1-40) monomer was found to decrease from eight to three residues when temperature was increased from 3 to 18 °C. At 3 °C the peptide shows structural propensities that correlate well with the suggested secondary structure regions of the peptide to be present in the fibrils, and with the -helical structure in membrane-mimicking systems. Our data leads to a structural model for the monomeric soluble -peptide with six different regions of secondary structure propensities. The peptide has two regions with -strand propensity (residues 16-24 and 31-40), two regions with high PII-helix propensity (residues 1-4 and 11-15) and two unstructured regions with higher mobility (residues 5-10 and 25-30) connecting the structural elements. Copyright © 2006 John Wiley & Sons, Ltd.
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| 15. |
- Flodin, Mats, et al.
(författare)
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Evaluation of Gentian cystatin C reagent on Abbott Ci8200 and calculation of glomerular filtration rate expressed in mL/min/1.73 m(2) from the cystatin C values in mg/L
- 2007
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Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Informa UK Limited. - 0036-5513 .- 1502-7686. ; 67:5, s. 560-567
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Estimation of the glomerular filtration rate (GFR) is essential when evaluating patients with kidney disease and treating patients with drugs eliminated from the circulation by the kidneys. Cystatin C has been shown in several studies to be superior to creatinine in the estimation of GFR. At our hospitals, there is an increasing demand for cystatin C and at present we perform approximately 1500 cystatin C analyses a month. We thus need the assay available 24 h/day and to have it on our routine chemistry instrument to minimize handling time per test and time to reported test results. MATERIAL AND METHODS: We have evaluated a new cystatin C immunoassay from Gentian (Gentian, Moss, Norway) on Architect ci8200 (Abbott Laboratories, Abbott Park, Ill., USA). A prerequisite at our hospital is that cystatin C results are reported as a calculated GFR in mL/min/1.73 m(2), so we also made a comparison with iohexol clearance. RESULTS: The Gentian cystatin C assay showed good agreement with the corresponding assay from Dade Behring (Deerfield, Ill., USA) and good inter-laboratory concordance. The assay has very low total imprecision, good linearity and strong correlation with iohexol clearance (R (2) = 0.956). The equation for the correlation curve is: y = 79.901x(-1.4389). CONCLUSIONS: There was low inter-laboratory variation between the three laboratories involved in the cystatin C evaluation, and thus all three laboratories can use the same equation for calculating the estimated GFR.
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| 16. |
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| 17. |
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| 18. |
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| 19. |
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| 20. |
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| 21. |
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| 22. |
- Weinstein, S. L., et al.
(författare)
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Adolescent idiopathic scoliosis
- 2008
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Ingår i: Lancet. - 1474-547X. ; 371:9623, s. 1527-37
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Tidskriftsartikel (refereegranskat)abstract
- Adolescent idiopathic scoliosis (AIS) affects 1-3% of children in the at-risk population of those aged 10-16 years. The aetiopathogensis of this disorder remains unknown, with misinformation about its natural history. Non-surgical treatments are aimed to reduce the number of operations by preventing curve progression. Although bracing and physiotherapy are common treatments in much of the world, their effectiveness has never been rigorously assessed. Technological advances have much improved the ability of surgeons to safely correct the deformity while maintaining sagittal and coronal balance. However, we do not have long-term results of these changing surgical treatments. Much has yet to be learned about the general health, quality of life, and self-image of both treated and untreated patients with AIS.
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| 23. |
- Werner, M, et al.
(författare)
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Autoimmune hepatitis in Sweden.
- 2007
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Ingår i: SCANDINAVIAN JOURNAL OF GASTROENTEROLOGY. - 0036-5521. ; 42, s. 15-15
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 24. |
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| 25. |
- Ahrendt, Hans-Joachim, et al.
(författare)
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Efficacy, acceptability and tolerability of the combined contraceptive ring, NuvaRing, compared with an oral contraceptive containing 30 mug of ethinyl estradiol and 3 mg of drospirenone
- 2006
-
Ingår i: Contraception. - : Elsevier BV. - 0010-7824. ; 74:6, s. 451-457
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: This randomized multicenter, open-label, trial compared efficacy, acceptability, tolerability and compliance of NuvaRing with a combined oral contraceptive (COC), containing 30 mug of ethinyl estradiol (EE) and 3 mg of drospirenone. METHOD: In this 13-cycle study, 983 women were randomized and treated (intent-to-treat population) with NuvaRing or COC. RESULTS: One in-treatment pregnancy occurred with NuvaRing (Pearl Index=0.25) (95% confidence interval [CI]: 0.006, 1.363) and four with the COC (Pearl Index=0.99) (95% CI: 0.269, 2.530). For both groups, compliance (89.2% NuvaRing, 85.5% COC) and satisfaction (84% NuvaRing; 87% COC) were high; the vast majority of women found NuvaRing easy to insert (96%) and remove (97%). Tolerability was similar; the most frequent adverse events with NuvaRing were related to ring use, whereas estrogen-related events were more common with the COC. CONCLUSION: NuvaRing has comparable efficacy and tolerability to a COC containing 30 mug of EE and 3 mg drospirenone. User acceptability of both methods was high.
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| 26. |
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| 27. |
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| 28. |
- Azarbayjani, Faranak, et al.
(författare)
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Increased susceptibility to phenytoin teratogenicity : Excessive generation of reactive oxygen species or impaired antioxidant defense?
- 2006
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Ingår i: Basic & Clinical Pharmacology & Toxicology. - : Wiley. - 1742-7835 .- 1742-7843. ; 99:4, s. 305-311
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Tidskriftsartikel (refereegranskat)abstract
- Phenytoin is a human and animal teratogen. Accumulating evidence suggests that the teratogenicity is associated with a potential of phenytoin to cause embryonic cardiac arrhythmia and resultant generation of toxic reactive oxygen species via hypoxia-reoxygenation mechanisms. The A/J mouse is more susceptible to phenytoin teratogenicity than other mouse strains. The aim of this study was to investigate whether A/J mice have other antioxidant enzyme activities than C57BL/6J and CD-1 mice. Also, strain differences in phenytoin effects on embryonic heart rate and rhythm were determined. Another objective was to determine whether a spin trapping agent with capacity to capture reactive oxygen species alter the developmental toxicity of phenytoin. Treatment with this agent resulted in a marked decrease in phenytoin teratogenicity, which supports the idea that reactive oxygen species are important mediators for the teratogenic action of phenytoin. The A/J mice embryos were most susceptible to the adverse cardiac effects of phenytoin and had the highest activity of superoxide dismutase and glutathione peroxidase, while the activity of catalase was the same in embryos of the three different strains. The high activities of antioxidant enzymes in the A/J stain indicate that the sensitivity to develop malformations is caused by excessive arrhythmia-related generation of reactive oxygen species rather than impaired antioxidant defense.
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| 29. |
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| 30. |
- Blum, J, et al.
(författare)
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Treatment of incomplete abortion and miscarriage with misoprostol
- 2007
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Ingår i: International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics. - : Wiley. - 0020-7292. ; 9999 Suppl 2, s. S186-S189
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Tidskriftsartikel (refereegranskat)
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| 31. |
- Cavallin, L, et al.
(författare)
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Can dynamic susceptibility contrast magnetic resonance imaging replace single-photon emission computed tomography in the diagnosis of patients with Alzheimer's disease? A pilot study
- 2006
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Ingår i: Acta radiologica (Stockholm, Sweden : 1987). - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 47:9, s. 977-985
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To compare single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) in a cohort of patients examined for suspected dementia, including patients with no objective cognitive impairment (control group), mild cognitive impairment (MCI), and Alzheimer's disease (AD). Material and Methods: Twenty-four patients, eight with AD, 10 with MCI, and six controls were investigated with SPECT using 99mTc-hexamethylpropyleneamine oxime (HMPAO) and dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) with gadobutrol. Three observers performed a visual interpretation of the SPECT and MR images using a four-point visual scale. Results: SPECT was superior to DSC-MRI in differentiating normal from pathological. All three observers showed statistically significant results in discriminating between the control group, AD, and MCI by SPECT, with a P value of 0.0006, 0.04, and 0.01 for each observer. The statistical results were not significant for MR ( P values 0.8, 0.1, and 0.2, respectively). Conclusion: DSC-MRI could not replace SPECT in the diagnosis of patients with Alzheimer's disease. Several patient- and method-related improvements should be made before this method can be recommended for clinical practice.
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| 32. |
- da Cruz Francisco, José, et al.
(författare)
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Application of supercritical carbon dioxide for the extraction of alkylresorcinols from rye bran
- 2005
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Ingår i: Journal of Supercritical Fluids. - : Elsevier BV. - 0896-8446. ; 35:3, s. 220-226
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Tidskriftsartikel (refereegranskat)abstract
- The use of supercritical CO, (SC-CO2) for extracting alkylresorcinols from rye bran was investigated. For pure SC-CO2, 35 MPa and 55 degrees C were used. SC-CO2 with 10% ethanol or methanol as co-solvents was tested at four pressure levels (8, 15, 30 and 35 MPa) and two temperatures (40 and 55 degrees C). Experiments were conducted at a constant SC-CO2 flow of 5 g/min for 2 h. For comparative purposes acetone at ambient temperature and pressure was also used for extraction. The best extractions were achieved when SC-CO2 was used with co-solvents. At 55 degrees C and 15-30 MPa, the use Of SC-CO2 with co-solvents has yielded from 8 to 80% (w/w) more extracted product than acetone. Yield of extracts was proportional to pressure (when above 30 MPa) and temperature. The results suggest that cleaner bran extracts can be obtained by using pure SC-CO2 followed by the addition of co-solvents. There is no clear advantage of using either methanol or ethanol. (c) 2005 Elsevier B.V. All rights reserved.
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| 33. |
- da Cruz Francisco, José, et al.
(författare)
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Extraction of rye bran by supercritical carbon dioxide: Influence of temperature, CO2, and cosolvent flow rates
- 2005
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 53:19, s. 7432-7437
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Tidskriftsartikel (refereegranskat)abstract
- Process parameter optimization for the supercritical CO2 extraction of rye bran to obtain alkylresorcinols (AR) was studied by carrying out a two-level fractional design experiment. Four parameters, temperature, CO2 flow rate, cosolvent percentage, and extraction time, presumed to influence the extraction process, were analyzed. A tentative fractionation of the crude extract was also carried out and is discussed. The best extracts were achieved when the CO2 flow rate and extraction time or temperature and cosolvent addition were kept high. It was found that temperature increase was not statistically significant within the range of the study performed, and the extraction time was thus the most important factor. A preliminary fractionation process in two cyclone separators yielded two fractions, one rich in AR components with higher molecular weights and the other rich in AR components with low molecular weight.
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| 34. |
- da Cruz Francisco, José, et al.
(författare)
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Isolation of alkylresorcinols: Classical and supercritical CO2 extraction methods
- 2006
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Ingår i: Modern Extraction Techniques: Food and Agricultural Samples (ACS Symposium). - 0097-6156. - 9780841239401 - 0841239401 ; 926, s. 51-61
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter focuses on the use of different methods for isolation of alkylresorcinols. Alkylresorcinols are members of a lipid group called non-isoprenoid phenolic lipids. Different aspects of the extraction by classical methods and supercritical CO2 are discussed. Supercritical CO2 extraction of alkylresorcinols from rye bran is discussed for the first time. As compared to the classical extraction methods, supercritical CO2 gives higher yields and it allows the separation of the crude extrac into long- and short-chain alkylresorcinol homologues.
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| 35. |
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| 36. |
- Danielsson, AJ, et al.
(författare)
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Associations between orthopaedic findings, ambulation and health-related quality of life in children with myelomeningocele
- 2008
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Ingår i: Journal of children's orthopaedics. - : SAGE Publications. - 1863-2521 .- 1863-2548. ; 2:1, s. 45-54
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Tidskriftsartikel (refereegranskat)abstract
- Modern principles for treatment of patients with myelomeningocele include early closure of the neural tube defect, neurosurgical treatment of hydrocephalus and treatment aimed at minimizing contractures and joint dislocations. The aim is to achieve a better survival rate and a better quality of life (QOL). Better ambulatory function is thought to improve the management of activities of daily living. This study focused on evaluating which factors might affect ambulation, function and health-related QOL in children with myelomeningocele. Methods Thirty-eight patients with neurological deficit from myelomeningocele were examined in an unbiased follow-up. This included a physical examination using validated methods for ambulatory function and neuromuscular status, chart reviews and evaluation of radiographs in terms of hip dislocation and spine deformity. The Pediatric Evaluation of Disability Inventory (PEDI) was used to measure mobility, self-care and social function, and the Child Health Questionnaire (CHQ-PF50) was used to measure QOL. Results Muscle function class, quadriceps strength, spasticity in hip and/or knee joint muscles and hip flexion contracture as well as the ambulatory level all affected functional mobility as well as self-care/PEDI. Patients with hip dislocation, spinal deformity or those who were mentally retarded also had significantly worse functional mobility. Besides being affected by the severity of the neurological lesion, self-care/PEDI was significantly impaired by hip flexion contracture and absence of functional ambulation. General health-related QOL was significantly lower in this patient group than for US norms. Nonambulatory and mentally retarded patients had a significantly lower physical function of their QOL (CHQ). Conclusions The severity of the disease, i.e. reduced muscle strength and occurrence of spasticity around hip/knee, affected ambulation, functional mobility and self-care. Acquired deformities (hip dislocation and spine deformity) affected functional ambulation only. Patients with reduced functional mobility and self-care experienced lower physical QOL. Children with myelomeningocele had significantly reduced QOL compared to healthy individuals.
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| 37. |
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| 38. |
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| 39. |
- Danielsson, Conny, et al.
(författare)
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Trace analysis of polychlorinated dibenzo-p-dioxins, dibenzofurans and WHO polychlorinated biphenyls in food using comprehensive two-dimensional gas chromatography with electron-capture detection
- 2005
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Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1086:1-2, s. 61-70
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Tidskriftsartikel (refereegranskat)abstract
- Trace analysis of 2,3,7,8-polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and the 12 WHO-PCBs (four non-ortho and eight mono-ortho congeners that have been assigned toxic equivalence factors, TEFs, by the World Health Organisation) was conducted by comprehensive two-dimensional gas chromatography with a micro electron-capture detector (GC x GC-mu ECD). Four food matrices (fish oil from herring, spiked cows' milk, vegetable oil and an eel extract) were analysed by two GC x GC laboratories, and four GC-HRMS laboratories generated reference values. The two GC x GC laboratories used different column combinations for separating the target analytes. For the first dimension, non-polar DB-XLB and VF-1 columns were used, and for the second dimension, an LC-50 liquid crystalline column with unique selectivity for planar compounds. The congener-specific and total toxic equivalence (TEQ) data obtained using DB-XLB x LC-50 were in good agreement with results obtained by the GC-HRMS laboratories. The WHO-PCB data obtained with the VF-1 x LC-50 combination was also good, but the PCDD/F concentrations were sometimes overestimated due to matrix interferences. GC x GC-mu ECD using DB-XLB x LC-50 seems to fulfil the European Community requirements of a screening method for PCDD/F and WHO-PCB TEQ in food.
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| 40. |
- Danielsson, Erik, et al.
(författare)
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A 4H-SiC BJT with an epitaxially regrown extrinsic base layer
- 2005
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Ingår i: Materials Science Forum. - 0255-5476 .- 1662-9752. ; 483, s. 905-908
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Tidskriftsartikel (refereegranskat)abstract
- 4H-SiC BJTs were fabricated using epitaxial regrowth instead of ion implantation to form a highly doped extrinsic base layer necessary for a good base ohmic contact. A remaining p(+) regrowth spacer at the edge of the base-emitter junction is proposed to explain a low current gain of 6 for the BJTs. A breakdown voltage of 1000 V was obtained for devices with Al implanted JTE.
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| 41. |
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| 42. |
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| 43. |
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| 44. |
- Danielsson, Lars, 1979, et al.
(författare)
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HMI principles for lateral safe applications
- 2007
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Ingår i: Universal Access in Human-Computer Interaction. Ambient Interaction. ; , s. 330-338
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Konferensbidrag (refereegranskat)
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| 45. |
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| 46. |
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| 47. |
- Danielsson, Sverker, et al.
(författare)
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Topochemical modification of fibres during kraft pulping
- 2005
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Ingår i: Appita Annu. Conf.. ; , s. 155-160
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Konferensbidrag (refereegranskat)abstract
- Xylan dissolution, degradation and redeposition in the birch kraft cook have been examined. The molecular weight of the dissolved xylan was determined through gel permeation chromatography and the loss in molecular weight could be correlated to the amount of degraded xylan in the initial parts of the cook. This indicates that peeling is the only significant xylan degradation reaction early in the cook. Two different birch black liquors containing xylan with the molecular weight of 12.200 g/mol and 5.950 g/mol respectively, were added to softwood kraft cooks in order to determine the effect on pulp strength properties by birch xylan. The results show an increase in both tensile strength and tensile stiffness. The magnitude of the strength increase was affected very much by the molecular weight of xylan. High molecular weight xylan addition increased the tensile strength with more than 10% measured at 1000 PFI revolutions. The tensile stiffness was also increased by xylan addition, high molecular weight to a larger extent than low molecular weight.
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| 48. |
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| 49. |
- Dey, Estera, et al.
(författare)
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The Cytotoxic and Genotoxic Effects of Conjugated Trans-2-Nonenal (T2N), an Off-Flavor Compound in Beer and Heat Processed food Arising from Lipid Oxidation
- 2005
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Ingår i: Polish Journal of Microbiology. - 1733-1331. ; 54:Supplement, s. 47-52
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the toxic effect of E(2)nonenal (trans-2-nonenal, T2N) and its conjugate with horse muscle myoglobin (Mb) tested on murine cell line L929 and human cell line A549, as well as the genotoxic effect of these compounds assayed by measuring of micronuclei in human cells K562. It is an aldehyde, which is occurring as the substance responsible for an off flavour in aged beers, but originates also from lipid oxidation in heat processed food. T2N is an aldehyde formed from linoleic acid as a secondary oxidation product. The modification of Mb with T2N was analyzed with the use of SDS-polyacrylamide gel electrophoresis (SDS-PAGE), and electrospray ionization mass spec-trometry (ESI-MS). Results from SDS-PAGE suggest that T2N substitutes Mb and additionally causes cross-linking with polymerization of Mb resulting in an insoluble fraction. The ESI-MS spectrum of the soluble fraction used in the toxicity tests, demonstrated that conjugation of T2N with Mb yielded Mb adducts with one residue of trans-2-nonenal per myoglobin molecule as the major fraction and adducts with different numbers of T2N molecules as minor fractions. In the cytotoxicity assay the T2N and its Mb conjugate causes 50% destruction of cells at the concentration 95-125 mg/ml and 200 mg/ml respectively, when L929 and A549 cell lines were used, whereas Mb control tested up to 2000 mg/ml was without any cytotoxic effect. In genotoxicity in vitro assay we have observed that the T2N and its Mb conjugate expressed the genotoxicity. The number of micronuclei in human K562 cells reached 26±2.16 promille (MN/1000 cells), comparing to 62 ± 8.64 MN/1000 cells for the reference free T2N, whereas a control value was 10.33 ±1.25 MN/1000 cells. The studied compounds expressed also the apoptotic effect in K562 cells as the number of apoptotic cells increased to 44.67 ±4.92 promille for T2N-Mb, comparing to 168.67 ±37.28 promille for free T2N, whereas a control value was 30.33 ± 1.36 promille for Mb. In these assays the T2N-Mb conjugate is several times more toxic in relation to control protein. Results indicate that T2N adducts with protein are potent to induce various cytotoxic and apoptotic effects when assayed in vitro tests. It suggests that higher level of such aldehyde might create in organism severe potential of toxicity.
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- Edvardsson, D., et al.
(författare)
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An experimental and theoretical investigation of the valence double photoionisation of the IC molecule
- 2007
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Ingår i: Chemical Physics. - : Elsevier BV. - 0301-0104 .- 1873-4421. ; 332:2-3, s. 249-254
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Tidskriftsartikel (refereegranskat)abstract
- The double valence photoelectron spectrum of ICl has been measured at two photon energies,303.78 angstrom and 379.3 angstrom, by the TOF-PEPECO technique. Relativistic molecular electronic structure calculations have been performed for electronic states connected to the three lowest groups of dissociation limits to support the interpretation, and vibrational constants have been calculated for the quasi-bound states. The two lowest double ionisation energies are found to be 27.45 +/- 0.1 eV (vertical) and 27.69 +/- 0.1 eV (vertical). They are associated with the X-3 Sigma(-)(0.1), electronic states of ICl2+, respectively, which are the only states predicted to be stable by the calculations. The two following states connected to the same configuration are in order a (1)Delta(2), and b (1)Sigma(+)(0). The double ionisation processes building up the spectrum are found to be mainly direct, and energies and widths of the bands are well reproduced by the calculations.
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