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Sökning: WFRF:(Helander A)

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  • Meyer, H., et al. (författare)
  • Overview of physics results from MAST
  • 2009
  • Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 49:10, s. 104017-
  • Tidskriftsartikel (refereegranskat)abstract
    • Several improvements to the MAST plant and diagnostics have facilitated new studies advancing the physics basis for ITER and DEMO, as well as for future spherical tokamaks (STs). Using the increased heating capabilities P-NBI <= 3.8 MW H-mode at I-P = 1.2 MA was accessed showing that the energy confinement on MAST scales more weakly with I-P and more strongly with B-t than in the ITER IPB98(y, 2) scaling. Measurements of the fuel retention of shallow pellets extrapolate to an ITER particle throughput of 70% of its original designed total throughput capacity. The anomalous momentum diffusion, chi(phi), is linked to the ion diffusion, chi(i), with a Prandtl number close to P-phi approximate to chi(phi)/chi(i) approximate to 1, although chi(i) approaches neoclassical values. New high spatial resolution measurements of the edge radial electric field, E-r, show that the position of steepest gradients in electron pressure and E-r (i.e. shearing rate) are coincident, but their magnitudes are not linked. The T-e pedestal width on MAST scales with root beta(ped)(pol) rather than rho(pol). The edge localized mode (ELM) frequency for type-IV ELMs, new in MAST, was almost doubled using n = 2 resonant magnetic perturbations from a set of four external coils (n = 1, 2). A new internal 12 coil set (n <= 3) has been commissioned. The filaments in the inter-ELM and L-mode phase are different from ELM filaments, and the characteristics in L-mode agree well with turbulence calculations. A variety of fast particle driven instabilities were studied from 10 kHz saturated fishbone like activity up to 3.8 MHz compressional Alfven eigenmodes. Fast particle instabilities also affect the off-axis NBI current drive, leading to fast ion diffusion of the order of 0.5 m(2) s(-1) and a reduction in the driven current fraction from 40% to 30%. EBW current drive start-up is demonstrated for the first time in a ST generating plasma currents up to 55 kA. Many of these studies contributed to the physics basis of a planned upgrade to MAST.
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  • Lloyd, B., et al. (författare)
  • Overview of physics results from MAST
  • 2007
  • Ingår i: Nuclear Fusion. - 0029-5515 .- 1741-4326. ; 47:10, s. S658-S667
  • Tidskriftsartikel (refereegranskat)abstract
    • Substantial advances have been made on the Mega AmpÚre Spherical Tokamak (MAST). The parameter range of the MAST confinement database has been extended and it now also includes pellet-fuelled discharges. Good pellet retention has been observed in H-mode discharges without triggering an ELM or an H/L transition during peripheral ablation of low speed pellets. Co-ordinated studies on MAST and DIII-D demonstrate a strong link between the aspect ratio and the beta scaling of H-mode energy confinement, consistent with that obtained when MAST data were merged with a subset of the ITPA database. Electron and ion ITBs are readily formed and their evolution has been investigated. Electron and ion thermal diffusivities have been reduced to values close to the ion neoclassical level. Error field correction coils have been used to determine the locked mode threshold scaling which is comparable to that in conventional aspect ratio tokamaks. The impact of plasma rotation on sawteeth has been investigated and the results have been well-modelled using the MISHKA-F code. Alfvén cascades have been observed in discharges with reversed magnetic shear. Measurements during off-axis NBCD and heating are consistent with classical fast ion modelling and indicate efficient heating and significant driven current. Central electron Bernstein wave heating has been observed via the O-X-B mode conversion process in special magnetically compressed plasmas. Plasmas with low pedestal collisionality have been established and further insight has been gained into the characteristics of filamentary structures at the plasma edge. Complex behaviour of the divertor power loading during plasma disruptions has been revealed by high resolution infra-red measurements.
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  • Hailer, Frank, et al. (författare)
  • Phylogeography of the white-tailed eagle, a generalist with large dispersal capacity
  • 2007
  • Ingår i: Journal of Biogeography. - : Wiley. - 0305-0270 .- 1365-2699. ; 34:7, s. 1193-1206
  • Tidskriftsartikel (refereegranskat)abstract
    • Aim Late Pleistocene glacial changes had a major impact on many boreal and temperate taxa, and this impact can still be detected in the present-day phylogeographic structure of these taxa. However, only minor effects are expected in species with generalist habitat requirements and high dispersal capability. One such species is the white-tailed eagle, Haliaeetus albicilla, and we therefore tested for the expected weak population structure at a continental level in this species. This also allowed us to describe phylogeographic patterns, and to deduce Ice Age refugia and patterns of postglacial recolonization of Eurasia. Location Breeding populations from the easternmost Nearctic (Greenland) and across the Palaearctic (Iceland, continental Europe, central and eastern Asia, and Japan). Methods Sequencing of a 500 base-pair fragment of the mitochondrial DNA control region in 237 samples from throughout the distribution range. Results Our analysis revealed pronounced phylogeographic structure. Overall, low genetic variability was observed across the entire range. Haplotypes clustered in two distinct haplogroups with a predominantly eastern or western distribution, and extensive overlap in Europe. These two major lineages diverged during the late Pleistocene. The eastern haplogroup showed a pattern of rapid population expansion and colonization of Eurasia around the end of the Pleistocene. The western haplogroup had lower diversity and was absent from the populations in eastern Asia. These results suggest survival during the last glaciation in two refugia, probably located in central and western Eurasia, followed by postglacial population expansion and admixture. Relatively high genetic diversity was observed in northern regions that were ice-covered during the last glacial maximum. This, and phylogenetic relationships between haplotypes encountered in the north, indicates substantial population expansion at high latitudes. Areas of glacial meltwater runoff and proglacial lakes could have provided suitable habitats for such population growth. Main conclusions This study shows that glacial climate fluctuations had a substantial impact on white-tailed eagles, both in terms of distribution and demography. These results suggest that even species with large dispersal capabilities and relatively broad habitat requirements were strongly affected by the Pleistocene climatic shifts.
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  • Jones, A Wayne, 1945-, et al. (författare)
  • Misleading results of ethanol analysis in urine specimens from rape victims suffering from diabetes
  • 2000
  • Ingår i: Journal of Clinical Forensic Medicine. - : Elsevier BV. - 1353-1131 .- 1532-2009. ; 7:3, s. 144-146
  • Tidskriftsartikel (refereegranskat)abstract
    • We report appreciably high concentrations of ethanol (82 and 102 mg/dL) in specimens of urine collected from two victims of date rape. Both girls (aged 15 and 18 years) suffered from diabetes mellitus, but adamantly denied drinking any alcohol before or after the incident. The presence of glycosuria and high risk of fungal infections in female diabetics suggests that ethanol was produced in vitro by fermentation after voiding. Making a routine test for sugar in the urine and ensuring that the sampling tubes contain sufficient sodium or potassium fluoride to inhibit glycolysis are recommended practices. A specific marker for post-sampling synthesis of ethanol might also be used such as the 5HTOL/5HIAA ratio.
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  • Alling, Christer, et al. (författare)
  • Revealing alcohol abuse: to ask or to test?
  • 2005
  • Ingår i: Alcoholism: Clinical and Experimental Research. - 0145-6008. ; 29:7, s. 1257-1263
  • Tidskriftsartikel (refereegranskat)
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  • Bergström, J, et al. (författare)
  • Ethyl glucuronide concentrations in two successive urinary voids from drinking drivers : Relationship to creatinine content and blood and urine ethanol concentrations
  • 2003
  • Ingår i: Forensic Science International. - 0379-0738 .- 1872-6283. ; 133:1-2, s. 86-94
  • Tidskriftsartikel (refereegranskat)abstract
    • The concentrations of alcohol in blood (BAC) and two successive urine voids (UAC) from 100 drunk drivers were compared with the concentration of ethyl glucuronide (EtG), a minor metabolite of ethanol in urine, and the urinary creatinine content as an indicator of dilution. The subjects consisted of 87 men with mean age 42.2 ▒ 14.2 years (▒standard deviation, S.D.) and 13 women with mean age 42.5 ▒ 14.4 years. Ethanol was measured in blood and urine by headspace gas chromatography (GC) and EtG was determined in urine by liquid chromatography-mass spectrometry (LC-MS). The mean UAC was 2.53 ▒ 1.15g/l for first void compared with 2.35 ▒ 1.17g/l for second void, decreasing by 0.18 ▒ 0.24g/l on average (P < 0.001 in paired t-test). The ratios of UAC/BAC were 1.35 ▒ 0.25 for first void and 1.20 ▒ 0.16 for second void and the difference of 0.15 ▒ 0.27 was statistically significant (P < 0.001). The UAC/BAC ratio was not correlated with creatinine content of the urine specimens, whereas the concentration of urinary EtG was positively correlated with creatinine (r=0.64 for first void and r=0.62 for second void). The UAC was not correlated with urinary EtG directly (r=-0.03 for first void and r=0.08 for second void) but after adjusting for the relative dilution of the specimens (EtG/creatinine ratio) statistically significant positive correlations were obtained (r=0.58 for first void and r=0.57 for second void). The dilution of the urine, as reflected in creatinine content, is important to consider when EtG measurements are interpreted. The excretion of EtG in urine, like glucuronide conjugates of other drugs, is influenced by diuresis. EtG represents a sensitive and specific marker of acute alcohol ingestion with applications in clinical and forensic medicine. ⌐ 2003 Elsevier Science Ireland Ltd. All rights reserved.
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  • Hailer, Frank, et al. (författare)
  • Bottlenecked but long-lived : high genetic diversity retained in white-tailed eagles upon recovery from population decline
  • 2006
  • Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 2:2, s. 316-319
  • Tidskriftsartikel (refereegranskat)abstract
    • Most of the white-tailed eagle (Haliaeetus albicilla) populations in Europe experienced dramatic declines during the twentieth century. However, owing to intense conservation actions and the ban of DDT and other persistent pollutants, populations are currently recovering. We show that despite passing through demographic bottlenecks, white-tailed eagle populations have retained significant levels of genetic diversity. Both genetic and ringing data indicate that migration between populations has not been a major factor for the maintenance of genetic variability. We argue that the long generation time of eagles has acted as an intrinsic buffer against loss of genetic diversity, leading to a shorter effective time of the experienced bottleneck. Notably, conservation actions taken in several small sub-populations have ensured the preservation of a larger proportion of the total genetic diversity than if conservation had focused on the population stronghold in Norway. For conservation programmes targeting other endangered, long-lived species, our results highlight the possibility for local retention of high genetic diversity in isolated remnant populations.
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  • Helander, A, et al. (författare)
  • Improved HPLC method for carbohydrate-deficient transferrin in serum
  • 2003
  • Ingår i: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 49:11, s. 1881-1890
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: There is need for a reference method for transferrin glycoforms in serum to which routine immunologic methods for the alcohol marker carbohydrate-deficient transferrin (CDT) can be traceable. We describe an improved HPLC method for transferrin glycoforms. Methods: Transferrin was iron-saturated by mixing the serum with ferric nitrilotriacetic acid, and lipoproteins were precipitated with dextran sulfate and calcium chloride. Separation of glycoforms was performed on a SOURCE 15Q anion-exchange column using salt gradient elution. Quantification relied on selective absorbance of the iron-transferrin complex at 470 run. The relative amount of each glycoform was calculated as a percentage of the area under the curve, using baseline integration. Results: The HPLC system provided reproducible separation and quantification of the asialo-, monosialo-, disialo-, trisialo-, tetrasialo-, pentasialo-, and hexasialotransferrin glycoforms. Most importantly, disialo- and trisialotransferrin were almost baseline separated. The intra- and interassay CV for disialotransferrin were <5%. Serum and the pretreated samples were stable for at least 2 days at 22 or 4 degreesC. Sera from 132 healthy controls contained [mean (SD)] 1.16 (0.25)% disialotransferrin, 4.77 (1.36)% trisialotransferrin, 80.18 (2.01)% tetrasialotransferrin, and 13.88 (1.69)% pentasialo- + hexasialotransferrin. In some cases of a high (>6%) trisialotransferrin, monosialotransferrin was detected at <0.25%. Asialotransferrin was not detected in control sera, but was detected in 57% of chronic heavy drinkers and in 62% of sera with greater than or equal to2% disialotransferrin. Conclusions: The HPLC method fulfills the requirements of a preliminary reference method for CDT and should work for any combination of serum transferrin glycoforms. This method could also be useful for confirming positive CDT results by immunoassays in medico-legal cases. (C) 2003 American Association for Clinical Chemistry.
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  • Janák, K, et al. (författare)
  • Enantiomer-specific accumulation of hexabromocyclododecanes in eggs of predatory birds
  • 2008
  • Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535. ; 73:1, Supplement 1
  • Tidskriftsartikel (refereegranskat)abstract
    • The diastereomeric composition of hexabromocyclododecane (HBCD) in eggs of peregrine falcon (Falco peregrinus), white-tailed sea eagle (Haliaeetus albicilla), guillemot (Uria aalge) and common tern (Sterna hirundo) as well as the guillemots’ main prey, herring (Clupea harengus) was determined by reversed-phase chromatography with triple-stage quadrupole mass spectrometric detection (LC–MS–MS). α-HBCD was the predominant diastereomer in all bird species, while in herring, γ-HBCD made a substantial contribution. Two, as yet unidentified diastereomers, were detected in common tern egg. The α-, β- and γ-HBCD (+) and (−) enantiomers were separated using a chiral stationary phase. The enantiomer fractions for α-HBCD differed substantially between different bird species as well as between guillemot and its prey, herring. Total HBCD levels determined by LC–MS–MS were comparable to those previously obtained by GC–MS.
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  • Kroke, A, et al. (författare)
  • Comparison of self-reported alcohol intake with the urinary excretion of 5-hydroxytryptophol:5-hydroxyindole-3-acetic acid, a biomarker of recent alcohol intake
  • 2001
  • Ingår i: The British journal of nutrition. - : Cambridge University Press (CUP). - 0007-1145 .- 1475-2662. ; 85:5, s. 621-627
  • Tidskriftsartikel (refereegranskat)abstract
    • Under-reporting of alcohol intake has been frequently reported. However, due to the lack of an objective reference method, e.g. a biomarker, information about the extent of under-reporting of alcohol intake obtained with dietary assessment instruments is not available. The objective of this study was to compare reported alcohol intake data derived from a 24 h recall with a biomarker of recent alcohol intake, the urinary excretion of 5-hydroxytryptophol (5-HTOL):5-hydroxyindole-3-acetic acid (5-HIAA). Embedded into the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study, Germany, a validation study that collected 24 h recall data and 24 h urine samples was conducted. Cohort study participants (n107) volunteered to participate in this validation study. Among them were five subjects who reported no consumption of alcoholic beverages but had a 5-HTOL:5-HIAA ratio that indicated recent alcohol intake when the clinical cut-off point was taken as a judging criterion. After exclusion of these under-reporters, the Pearson's correlation coefficient between reported alcohol intake and the 5-HTOL:5-HIAA ratio was 0.92 (P<0.0001). Except for low alcohol intake of <0.1 g/kg body mass, a significant increase in 5-HTOL:5-HIAA excretion was observed with increasing amounts of alcohol intake. In conclusion, the 5-HTOL:5-HIAA excretion ratio appears to be a valuable quantitative biomarker of recent alcohol consumption. Denial of alcohol intake can be detected, but for the quantification of under-reporting of alcohol intake 24 h reference data are not yet available. With these data at hand, however, 5-HTOL:5-HIAA could become a biomarker for validation purposes in nutritional epidemiology.
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  • Mozaffari, F, et al. (författare)
  • NK-cell and T-cell functions in patients with breast cancer : effects of surgery and adjuvant chemo- and radiotherapy
  • 2007
  • Ingår i: British Journal of Cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 97:1, s. 105-111
  • Tidskriftsartikel (refereegranskat)abstract
    • Breast cancer is globally the most common malignancy in women. Her2-targeted monoclonal antibodies are established treatment modalities, and vaccines are in late-stage clinical testing in patients with breast cancer and known to promote tumour-killing through mechanisms like antibody-dependent cellular cytotoxicity. It is therefore increasingly important to study immunological consequences of conventional treatment strategies. In this study, functional tests and four-colour flow cytometry were used to detect natural killer (NK)-cell functions and receptors as well as T-cell signal transduction molecules and intracellular cytokines in preoperative breast cancer patients, and patients who had received adjuvant radiotherapy or adjuvant combined chemo-radiotherapy as well as in age-matched healthy controls. The absolute number of NK cells, the density of NK receptors as well as in vitro quantitation of functional NK cytotoxicity were significantly higher in preoperative patients than the post-treatments group and controls. A similar pattern was seen with regard to T-cell signalling molecules, and preoperative patients produced significantly higher amounts of cytokines in NK and T cells compared to other groups. The results indicate that functions of NK and T cells are well preserved before surgery but decrease following adjuvant therapy, which may speak in favour of early rather than late use of immunotherapeutic agents such as trastuzumab that may depend on intact immune effector functions.
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  • Alling, C, et al. (författare)
  • Revealing alcohol abuse: to ask or to test?
  • 2005
  • Ingår i: Alcoholism, clinical and experimental research. - : Wiley. - 0145-6008. ; 29:7, s. 1257-1263
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