| 1. |
- Beecham, Ashley H, et al.
(författare)
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Analysis of immune-related loci identifies 48 new susceptibility variants for multiple sclerosis.
- 2013
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Ingår i: Nature genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 45:11, s. 1353-60
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Tidskriftsartikel (refereegranskat)abstract
- Using the ImmunoChip custom genotyping array, we analyzed 14,498 subjects with multiple sclerosis and 24,091 healthy controls for 161,311 autosomal variants and identified 135 potentially associated regions (P < 1.0 × 10(-4)). In a replication phase, we combined these data with previous genome-wide association study (GWAS) data from an independent 14,802 subjects with multiple sclerosis and 26,703 healthy controls. In these 80,094 individuals of European ancestry, we identified 48 new susceptibility variants (P < 5.0 × 10(-8)), 3 of which we found after conditioning on previously identified variants. Thus, there are now 110 established multiple sclerosis risk variants at 103 discrete loci outside of the major histocompatibility complex. With high-resolution Bayesian fine mapping, we identified five regions where one variant accounted for more than 50% of the posterior probability of association. This study enhances the catalog of multiple sclerosis risk variants and illustrates the value of fine mapping in the resolution of GWAS signals.
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| 2. |
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| 3. |
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| 4. |
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| 5. |
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| 6. |
- Sawcer, Stephen, et al.
(författare)
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Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis
- 2011
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 476:7359, s. 214-219
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Tidskriftsartikel (refereegranskat)abstract
- Multiple sclerosis is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability. Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals, and systematic attempts to identify linkage in multiplex families have confirmed that variation within the major histocompatibility complex (MHC) exerts the greatest individual effect on risk. Modestly powered genome-wide association studies (GWAS) have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects have a key role in disease susceptibility. Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9,772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the HLA-DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the class I region. Immunologically relevant genes are significantly overrepresented among those mapping close to the identified loci and particularly implicate T-helper-cell differentiation in the pathogenesis of multiple sclerosis.
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| 7. |
- Bagatskii, M.I., et al.
(författare)
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Low-temperature dynamics of matrix isolated methane molecules in fullerite C60 : the heat capacity, isotope effects
- 2014
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Ingår i: Low temperature physics (Woodbury, N.Y., Print). - : American Institute of Physics (AIP). - 1063-777X .- 1090-6517. ; 40:8, s. 678-684
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Tidskriftsartikel (refereegranskat)abstract
- The heat capacity of the interstitial solid solution (CH4)0.4C60 has been investigated in the temperature interval 1.4–120 K. The contribution of CH4 molecules to the heat capacity of the solution has been separated. The contributions of CH4 and CD4 molecules to the heat capacity of the solutions (CH4)0.40C60 and (CD4)0.40C60 have been compared. It is found that above 90 K the character of the rotational motion of CH4 and CD4 molecules changes from libration to hindered rotation. In the interval 14–35 K the heat capacities of CH4 and CD4 molecules are satisfactorily described by contributions of the translational and libration vibrations, as well as the tunnel rotation for the equilibrium distribution of the nuclear spin species. The isotope effect is due to mainly the difference in the frequencies of local translational and libration vibrations of molecules CH4 and CD4. The contribution of the tunnel rotation of the CH4 and CD4 molecules to the heat capacity is dominant below 8 K. The isotopic effect is caused by the difference between both the conversion rates and the rotational spectra of the nuclear spin species of CH4 and CD4 molecules. The conversion rate of CH4 molecules is several times lower than that of CD4 ones. Weak features observed in the curves of temperature dependencies of the heat capacity of CH4 and CD4 molecules near 6 and 8 K, respectively, are most likely a manifestation of first-order polyamorphic phase transitions in the orientational glasses of these solutions.
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| 8. |
- Bagatskii, M.I., et al.
(författare)
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The specific heat and the radial thermal expansion of bundles of single-walled carbon nanotubes
- 2012
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Ingår i: Low temperature physics (Woodbury, N.Y., Print). - : American Institute of Physics (AIP). - 1063-777X .- 1090-6517. ; 38:6, s. 523-528
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Tidskriftsartikel (refereegranskat)abstract
- The specific heat at constant pressure C(T) of bundles of single-walled carbon nanotubes (SWNTs) closed at their ends has been investigated in the temperature interval of 2–120 K. It is found that the curve C(T) has features near 5, 36, 80, and 100 K. The experimental results on the C(T) and the radial thermal expansion coefficient αR(T) of bundles of SWNTs oriented perpendicular to the sample axis have been compared. It is found that the curves C(T) and αR(T) exhibit a similar temperature behavior at T > 10 K. The temperature dependence of the Grüneisen coefficient γ(T) has been calculated. The curve γ(T) also has a feature near 36 K. Above 36 K the Grüneisen coefficient is practically independent of temperature (γ ≈ 4). Below 36 K, γ(T) decreases monotonically with lowering temperature and becomes negative at T < 6 K.
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| 9. |
- Jansson, S. -A, et al.
(författare)
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Socioeconomic evaluation of well-characterized allergy to staple foods in adults
- 2014
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Ingår i: Allergy. European Journal of Allergy and Clinical Immunology. - : Wiley. - 0105-4538 .- 1398-9995. ; 69:9, s. 1241-1247
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Tidskriftsartikel (refereegranskat)abstract
- Background: The aim of the present study was to evaluate if total, direct, indirect, and intangible costs differ between a cohort of adults with well-characterized allergy to staple foods ('cases') and controls. Methods: Swedish adults with objectively diagnosed food allergy to cow's milk, hen's egg, and/or wheat were recruited at an outpatient allergy clinic. Controls age- and sex-matched to cases were recruited from the same geographic area. For assessing the household costs of food allergy, a disease-specific socioeconomic questionnaire, developed within EuroPrevall, was utilized. Results: Overall annual total costs at the household level were significantly higher among adults with food allergy compared with controls (the difference amounted to 8164 (sic) ), whereas direct costs did not differ between cases and controls. However, household healthcare costs and costs for medicines were significantly higher for cases vs controls. Furthermore, indirect costs were significantly higher for households with food-allergic adults vs households without food-allergic adults. Specifically, more time was spent on performing domestic tasks due to a family member's food-allergy-related illness, as well as shopping and preparing food, and seeking food-allergy-related information. Presence of food allergy also affected intangible costs. Adults with food allergy experienced overall lower health status compared with controls. Conclusions: Swedish adults with allergy to staple foods have higher total costs determined as direct, indirect, and intangible costs using the disease-specific socioeconomic questionnaire. Thus, total costs were 8164 (sic) higher per year in households with at least one adult allergic to staple foods compared with controls.
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Bagatskii, M. I., et al.
(författare)
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Low-temperature heat capacity of fullerite C-60 doped with deuteromethane
- 2012
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Ingår i: Low temperature physics (Woodbury, N.Y., Print). - Melville, NY : American Institute of Physics (AIP). - 1063-777X .- 1090-6517. ; 38:1, s. 67-73
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Tidskriftsartikel (refereegranskat)abstract
- The heat capacity C of fullerite doped with deuteromethane (CD4)(0.4)(C-60) has been investigated in the temperature interval 1.2-120K. The contribution Delta C-CD4 of the CD4 molecules to the heat capacity C has been isolated. It is shown that at T approximate to 120K the rotational motion of CD4 molecules in the octahedral voids of the C-60 lattice is weakly hindered. When the temperature is lowered to 80K, the rotational motion of the CD4 molecules changes from weakly hindered rotation to libration. In the range T = 1.2-30 K, Delta C-CD4 is described quite accurately by the sum of contributions from the translational and librational vibrations and tunneling rotation of CD4 molecules. The contribution of tunneling rotation to the heat capacity Delta C-CD4(T) is dominant below 5K. The effect of nuclear-spin conversion of the CD4 molecules on the heat capacity has been observed and the characteristic times for nuclear spin conversion between the lowest levels of the A- and T-species of CD4 molecules at T < 5K have been estimated. A feature observed in Delta C-CD4(T) near T = 5.5K is most likely a manifestation of a first-order phase transition in the orientational glass form of the solution. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3677237]
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| 14. |
- Danilchenko, Boris A., et al.
(författare)
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1/f noise and mechanisms of the conductivity in carbon nanotube bundles
- 2011
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Ingår i: Carbon. - : Elsevier Ltd. - 0008-6223 .- 1873-3891. ; 49:15, s. 5201-5206
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Tidskriftsartikel (refereegranskat)abstract
- Experimental results are reported of the investigation of conductivity mechanisms in metallic single-wall carbon nanotube (SWCNT) bundles in a wide temperature range from 4.2 K to 300 K. The temperature dependence of the resistance and noise parameters – the logarithmic slope of the current dependence of noise as well as the normalized current noise – are compared. Remarkable changes in noise characteristics are registered at temperatures typical of the transition from hopping conductivity to Luttinger liquid conductivity and the transition from Luttinger liquid conductivity to diffusion conductivity. In the first transition region, the slope of the normalized noise level of the current changes significantly as a function of temperature. In the region of diffusion conductivity, a stronger variation of the normalized noise level is revealed. These changes in noise properties are correlated with changes in the transport characteristics of SWCNT bundles that allow us to adequately explain the mechanisms of conductivity in the system.
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| 15. |
- Ekvall, Tomas, et al.
(författare)
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Bridging the gap between the sustainability pillars
- 2012
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Konferensbidrag (refereegranskat)abstract
- A thorough assessment of the sustainability performance of a product, a system, or a decision requires expertise on environmental, economic, and social aspects. In an assessment that involves researchers from different disciplines, communication is challenging because of different background knowledge, terminology, research traditions, etc.In the research program Towards Sustainable Waste Management, a new approach to interdisciplinary interaction was tested. The program included a group of researchers on life cycle assessment (LCA) and systems analysis of waste management. To this group, specialists in national economy, environmental psychology, and ethnology were linked in various projects. In each specific research project at least 20% of the budget was allocated to a waste LCA expert, who, through participating actively in the project, would be an interpreter, a two-way bridge between the disciplines. The first purpose of this LCA expert was to interpret the sustainability questions and to help make the research relevant for the overall purpose of the research program. The second purpose was to interpret the results of the specialists’ research and to help making the results useful for the overall program.Our experience demonstrates that this set-up forces the specialists and their interpreters/bridges to face the challenge of understanding each other. Establishing such an interdisciplinary interaction requires that the researchers share a mutual interest in trying to reach understanding. However, despite this interest and despite the significant resources made available for the participation, our collaboration was restricted by the fact that it can be difficult for the specialists to find suitable tasks in their projects for the LCA expert. The chance of the interaction being successful increases if the background knowledge of the researchers in the project overlaps, if they have similar research cultures, if they share a common interest in the research questions, and/or if the disciplinary scientists are accustomed to interdisciplinary collaboration.
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| 16. |
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| 17. |
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| 18. |
- Finnveden, Göran, et al.
(författare)
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Developing and evaluating new policy instruments for sustainable waste management
- 2012
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Ingår i: International Journal of Environment and Sustainable Development (IJESD). - 1474-6778 .- 1478-7466. ; 11:1, s. 19-31
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this paper is to suggest a number of interesting policy instruments that can make the Swedish waste management system more sustainable. Approximately 60 suggestions for policy instruments were gathered through a number of workshops with stakeholders. These were further prioritised in a workshop with stakeholders and by the research team resulting in a list of 15 instruments: information to citizens and companies; tax on raw materials; weight-based waste collection fee; environmentally differentiated waste collection fee; waste minimisation in enterprises; 'Advertising brochures - yes, please!'; recycling certificates; developed collection systems; tax on incineration of waste from fossil fuels; tax on incineration of waste; including waste in green certificates for electricity production; tax on hazardous substances; labelling of goods with hazardous substances; improved control by authorities; differentiated VAT and ban on incineration of recyclable materials. Several policy instruments are needed that can complement each other.
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| 19. |
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| 20. |
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| 21. |
- Idh, Jonna, et al.
(författare)
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Resistance to First-Line Anti-TB Drugs is Associated with Reduced Nitric Oxide Susceptibility in Mycobacterium tuberculosis
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 7:1, s. e39891-
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Tidskriftsartikel (refereegranskat)abstract
- Background and objective: The relative contribution of nitric oxide (NO) to the killing of Mycobacterium tuberculosis in human tuberculosis (TB) is controversial, although this has been firmly established in rodents. Studies have demonstrated that clinical strains of M. tuberculosis differ in susceptibility to NO, but how this correlates to drug resistance and clinical outcome is not known.Methods: In this study, 50 sputum smear- and culture-positive patients with pulmonary TB in Gondar, Ethiopia were included. Clinical parameters were recorded and drug susceptibility profile and spoligotyping patterns were investigated. NO susceptibility was studied by exposing the strains to the NO donor DETA/NO.Results: Clinical isolates of M. tuberculosis showed a dose- and time-dependent response when exposed to NO. The most frequent spoligotypes found were CAS1-Delhi and T3_ETH in a total of nine known spoligotypes and four orphan patterns. There was a significant association between reduced susceptibility to NO (>10% survival after exposure to 1mM DETA/NO) and resistance against first-line anti-TB drugs, in particular isoniazid (INH). Patients infected with strains of M. tuberculosis with reduced susceptibility to NO showed no difference in cure rate or other clinical parameters, but a tendency towards lower rate of weight gain after two months of treatment.Conclusion: There is a correlation between resistance to first-line anti-TB drugs and reduced NO susceptibility in clinical strains of M. tuberculosis. Further studies including the mechanisms of reduced NO susceptibility are warranted and could identify targets for new therapeutic interventions.
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| 22. |
- Jeong, S. H., et al.
(författare)
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Liquid alloy printing of microfluidic stretchable electronics
- 2012
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 12:22, s. 4657-4664
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Tidskriftsartikel (refereegranskat)abstract
- Recently, microfluidic stretchable electronics has attracted great interest from academia since conductive liquids allow for larger cross-sections when stretched and hence low resistance at longer lengths. However, as a serial process it has suffered from low throughput, and a parallel processing technology is needed for more complex systems and production at low costs. In this work, we demonstrate such a technology to implement microfluidic electronics by stencil printing of a liquid alloy onto a semi-cured polydimethylsiloxane (PDMS) substrate, assembly of rigid active components, encapsulation by pouring uncured PDMS on-top and subsequent curing. The printing showed resolution of 200 μm and linear resistance increase of the liquid conductors when elongated up to 60%. No significant change of resistance was shown for a circuit with one LED after 1000 times of cycling between a 0% and an elongation of 60% every 2 s. A radio frequency identity (RFID) tag was demonstrated using the developed technology, showing that good performance could be maintained well into the radio frequency (RF) range.
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| 23. |
- Keskitalo, M., et al.
(författare)
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The influence of shielding gas on the properties of laser welded stainless steel
- 2013
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Ingår i: 14th NOLAMP Conference. - Luleå : Luleå tekniska universitet. - 9789174396881 - 9789174396898 ; , s. 155-161
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Argon is generally used as shielding gas for laser welding. As Argon is an inert gas it doesnot have influence on the microstructure of the weld material or on the heat input of the weld,whereas nitrogen has solubility to austenite. Therefore nitrogen as an interstitial atomincreases the hardness of the weld. This has been detected when comparing the hardnessprofiles of nitrogen shielded welds of austenitic stainless steel with Argon shielded welds.Nitrogen as the shielding gas can compensate the softer structure of the weld in workhardenedand nitrogen-alloyed steels.For the duplex stainless steel grades the nitrogen additions promote formation ofaustenite in the weld, which decreases the risk of lowered toughness. In this study theinfluence of nitrogen shielding gas on the strength of the laser weld has been examined. Thestrength of laser welds of nitrogen alloyed work-hardened stainless steel seems to be slightlybetter when using nitrogen shielding gas compared to welds for argon shielding gas. It hasalso been verified that nitrogen as shielding gas decreases the risk of weak toughness of laserwelded duplex stainless steel.
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| 24. |
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| 25. |
- Norström, Elin, et al.
(författare)
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Late Quaternary vegetation dynamics and hydro-climate in the Drakensberg, South Africa
- 2014
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 105, s. 48-65
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Tidskriftsartikel (refereegranskat)abstract
- Abstract A multi-proxy study of a sediment sequence from Braamhoek wetland, covering the last c. 16,000 years, reveals a record of regional climate and vegetation dynamics in the Drakensberg region, South Africa, including signals from both the organic sediment fraction (fossil pollen, charcoal, n-alkane abundance, n-alkane δ13C, TOC) and the inorganic fraction (mineral magnetic properties). The reconstruction, supported by a robust chronology, indicates two major periods of increased regional wetness during the late Pleistocene to early Holocene phase (c. 13,800–12,600 cal yr BP; c. 10,200–8500 cal yr BP) and one during the late Holocene (c. 2000 cal yr BP to present). Drier conditions are recorded during the Younger Dryas (c. 12,600–11,300 cal yr BP) and mid-Holocene (c. 7000–2000 cal yr BP). A major decline in fynbos vegetation during the early Holocene suggests a shift towards warmer temperatures and possibly towards less pronounced winter rains in eastern South Africa from c. 8500 cal yr BP. Comparison with records from interior of South Africa show relatively high inter-site variability, however, the Braamhoek moisture proxies do co-vary with the speleothem isotope records from Makapansgat, suggesting a similar hydro-climate evolution in eastern and interior parts of the summer rainfall region during the studied period. On multi-millennial time scales, an inverse hydro-climatological pattern is evident between these two South African records and reconstructions from tropical locations in southeast Africa. Such a rainfall dipole between eastern tropical and southern Africa, has previously been identified on shorter time scales, i.e. on inter-annual to millennial scales. The Braamhoek study suggests that a similar dipole pattern is acting also on a multi-millennial perspective. These long-term precipitation anomalies are tentatively coupled to teleconnections from multi-millennial changes in the dynamics of the Indian Ocean Dipole (IOD) and El Niño-Southern Oscillation (ENSO).
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| 26. |
- Rondahl, E., et al.
(författare)
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The risk of HCV RNA contamination in serology screening instruments with a fixed needle for sample transfer
- 2014
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Ingår i: Journal of Clinical Virology. - : Elsevier BV. - 1386-6532 .- 1873-5967. ; 60:2, s. 172-173
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Tidskriftsartikel (refereegranskat)abstract
- Background: Hepatitis C diagnostics involve antibody screening and confirmation of current infection by detection of HCV RNA positivity. In screening instruments with fixed pipetting needle, there is a risk of sample carry-over contamination. Objectives: The aim of this study was to evaluate the risk of such contamination in a proposed clinical setting. Study design: In the present study, known HCV RNA positive (n= 149) and negative (n= 149) samples were analysed by anti-HCV Abbott in an Architect instrument in an alternating fashion in order to test for contamination. Results: In subsequent retesting of the previously HCV RNA-negative samples, six samples (4%) were positive by the Cobas Taqman assay with a maximum level of 33. IU/mL. The results show that there is a risk for transfer of HCV in the Architect instrument but they also show that the levels of HCV RNA observed are low. Conclusions: We conclude that complementary HCV RNA testing on samples identified as anti-HCV positive by screening can be recommended because the complementary results are reliable in the majority of cases when either HCV RNA is negative or HCV RNA is positive with a level >1000. IU/mL. In a minority of cases, with low HCV RNA after anti-HCV antibody screening, cross-contamination should be suspected and a new sample requested for HCV RNA testing. This strategy would reduce the need for obtaining a new sample from the vast majority of patients with a newly discovered HCV antibody positivity. © 2014 The Authors.
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| 27. |
- Sanchez, B C, et al.
(författare)
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Prolonged tamoxifen treatment increases relapse-free survival for patients with primary breast cancer expressing high levels of VEGF.
- 2010
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Ingår i: European journal of cancer (Oxford, England : 1990). - : Elsevier BV. - 1879-0852 .- 0959-8049. ; 46:9, s. 1580-7
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Tidskriftsartikel (refereegranskat)abstract
- Previous retrospective studies have shown that high intratumoural levels of vascular endothelial growth factor (VEGF) correlate with an inferior outcome for patients treated with adjuvant tamoxifen. Our objectives were to validate the impact of VEGF on survival after adjuvant tamoxifen and to investigate the interaction between VEGF and treatment duration. For this purpose tumour homogenates from 402 patients with operable oestrogen receptor positive breast cancer (BC), treated with tamoxifen for 2 (n=149) or 5 years (n=253) as the only systemic adjuvant therapy were included. The median follow-up time for surviving patients was 9.8 years (range 0.5-14.8 years). Expression of VEGF was assessed by an enzyme-linked immunosorbent assay and investigated in relation to the standard BC parameters and survival. In the total population, higher VEGF was significantly correlated with shorter recurrence-free survival (RFS) (HR=1.63, 95%CI=1.11-2.39, p=0.010), breast cancer corrected survival (BCCS) (HR=1.82, 95%CI=1.13-2.93, p=0.014) and overall survival (OS) (HR=1.51, 95%CI=1.11-2.05, p=0.009). High VEGF was significantly associated with reduced RFS (HR=2.61, 95%CI=1.45-4.70, p=0.001) after two years of tamoxifen, whilst no difference was seen in patients treated for five years (HR=1.09, 95%CI=0.64-1.84, p=0.760). A statistically significant interaction was observed between high VEGF expression and improved RFS after 5-year tamoxifen (p=0.034). In concordance with previous studies, high VEGF was significantly correlated with shorter survival. We present data not reported previously revealing that patients expressing high levels of VEGF display a better outcome provided that tamoxifen is given for five years. Further studies on the impact of VEGF on a 5-year regimen are motivated.
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| 28. |
- Spadiut, Oliver, et al.
(författare)
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Building Custom Polysaccharides in Vitro with an Efficient, Broad-Specificity Xyloglucan Glycosynthase and a Fucosyltransferase
- 2011
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 133:28, s. 10892-10900
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Tidskriftsartikel (refereegranskat)abstract
- The current drive for applications of biomass-derived compounds, for energy and advanced materials, has led to a resurgence of interest in the manipulation of plant polymers. The xyloglucans, a family of structurally complex plant polysaccharides, have attracted significant interest due to their intrinsic high affinity for cellulose, both in muro and in technical applications. Moreover, current cell wall models are limited by the lack of detailed structure-property relationships of xyloglucans, due to a lack of molecules with well-defined branching patterns. Here, we have developed a new, broad-specificity "xyloglucan glycosynthase", selected from active-site mutants of a bacterial endoxyloglucanase, which catalyzed the synthesis of high molar mass polysaccharides, with complex side-chain structures, from suitable glycosyl fluoride donor substrates. The product range was further extended by combination with an Arabidopsis thaliana alpha(1 -> 2)-fucosyltransferase to achieve the in vitro synthesis of fucosylated xyloglucans typical of dicot primary cell walls. These enzymes thus comprise a toolkit for the controlled enzymatic synthesis of xyloglucans that are otherwise impossible to obtain from native sources. Moreover, this study demonstrates the validity of a chemo-enzymatic approach to polysaccharide synthesis, in which the simplicity and economy of glycosynthase technology is harnessed together with the exquisite specificity of glycosyltransferases to control molecular complexity.
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| 29. |
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| 30. |
- Sundqvist, E., et al.
(författare)
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Cytomegalovirus seropositivity is negatively associated with multiple sclerosis
- 2014
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Ingår i: Multiple Sclerosis. - : SAGE Publications. - 1352-4585 .- 1477-0970. ; 20:2, s. 165-173
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Tidskriftsartikel (refereegranskat)abstract
- Background: Epidemiological data suggest a role for common viruses in the pathogenesis of multiple sclerosis (MS), and recent data showed a negative association of past cytomegalovirus (CMV) infection on pediatric MS risk. Objective: Our aim was to analyze the association of CMV infection with MS risk in an adult case-control material. A meta-analysis was performed to validate our findings. Methods: Epidemiological Investigation in MS (EIMS) is a case-control study with incident cases and population-based controls. Anti-CMV antibody titers were measured with ELISA, and HLA-A and DRB1 genotyping was performed with SSP-PCR, in 658 MS cases, who all fulfilled the McDonald criteria for MS, and 786 controls. Results: CMV seropositivity was associated with a decreased MS risk, OR = 0.73 (0.58-0.92 95% CI), p = 0.005, adjusted for index age, gender, smoking, sun exposure, EBNA1 IgG titer and HLA-A*02 and DRB1*15. When we removed all cases and controls younger than 18 years at index, the protective effect was still apparent. Conclusions: CMV is negatively associated with adult-onset MS pathology, consistent with results from a study on pediatric MS cases. It remains to be shown whether this negative association is due to a true protective effect of CMV infection on MS risk. © 2013 The Author(s).
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| 31. |
- Sundqvist, E., et al.
(författare)
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Epstein-Barr virus and multiple sclerosis : interaction with HLA
- 2012
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Ingår i: Genes and Immunity. - : Springer Science and Business Media LLC. - 1466-4879 .- 1476-5470. ; 13:1, s. 14-20
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Tidskriftsartikel (refereegranskat)abstract
- Epstein-Barr virus (EBV) infection, history of infectious mononucleosis (IM) and HLA-A and DRB1 have all been proposed as risk factors for multiple sclerosis (MS). Our aim was to analyse possible interactions between antibodies against Epstein-Barr virus nuclear antigen 1 (EBNA1) or EBNA1 fragments, presence of DRB1*15 and absence of A*02. The study population includes newly diagnosed cases and matched controls. Interaction on the additive scale was calculated using attributable proportion due to interaction (AP), which is the proportion of the incidence among individuals exposed to two interacting factors that is attributable to the interaction per se. IM showed association with MS, odds ratio (OR) = 1.89 (1.45-2.48% confidence interval (Cl)), as did raised EBNA1 IgG OR = 1.74 (1.38-2.18 95%CI). All EBNA1 fragment IgGs were associated with MS risk. However, EBNA1 fragment 385-420 IgG levels were more strongly associated to MS than total EBNA1 IgG, OR = 3.60 (2.75-4.72 95%CI), and also interacted with both DRB1*15 and absence of A*02, AP 0.60 (0.45-0.76 95%CI) and AP 0.39 (0.18-0.61 95%CI), respectively. The observed interaction between HLA class I and 11 genotype and reactivity to EBV-related epitopes suggest that the mechanism through which HLA genes influence the risk of MS may, at least in part, involve the immune control of EBV infection.
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| 32. |
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| 33. |
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| 34. |
- Sundqvist, Hanna S., et al.
(författare)
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Arctic Holocene proxy climate database - new approaches to assessing geochronological accuracy and encoding climate variables
- 2014
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Ingår i: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 10:4, s. 1605-1631
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Tidskriftsartikel (refereegranskat)abstract
- We present a systematic compilation of previously published Holocene proxy climate records from the Arctic. We identified 170 sites from north of 58 degrees N latitude where proxy time series extend back at least to 6 cal ka (all ages in this article are in calendar years before present - BP), are resolved at submillennial scale (at least one value every 400 +/- 200 years) and have age models constrained by at least one age every 3000 years. In addition to conventional meta-data for each proxy record (location, proxy type, reference), we include two novel parameters that add functionality to the database. First, climate interpretation is a series of fields that logically describe the specific climate variable(s) represented by the proxy record. It encodes the proxy-climate relation reported by authors of the original studies into a structured format to facilitate comparison with climate model outputs. Second, geochronology accuracy score (chron score) is a numerical rating that reflects the overall accuracy of C-14-based age models from lake and marine sediments. Chron scores were calculated using the original author-reported C-14 ages, which are included in this database. The database contains 320 records (some sites include multiple records) from six regions covering the circumpolar Arctic: Fennoscandia is the most densely sampled region (31% of the records), whereas only five records from the Russian Arctic met the criteria for inclusion. The database contains proxy records from lake sediment (60 %), marine sediment (32 %), glacier ice (5 %), and other sources. Most (61 %) reflect temperature (mainly summer warmth) and are primarily based on pollen, chironomid, or diatom assemblages. Many (15 %) reflect some aspect of hydroclimate as inferred from changes in stable isotopes, pollen and diatom assemblages, humification index in peat, and changes in equilibrium-line altitude of glaciers. This comprehensive database can be used in future studies to investigate the spatio-temporal pattern of Arctic Holocene climate changes and their causes. The Arctic Holocene data set is available from NOAA Paleoclimatology.
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| 35. |
- Sundqvist, Hanna S., et al.
(författare)
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Evidence of a large cooling between 1690 and 1740 AD in southern Africa
- 2013
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- A 350-year-long, well-dated delta O-18 stalagmite record from the summer rainfall region in South Africa is positively correlated with regional air surface temperatures at interannual time scales. The coldest period documented in this record occurred between 1690 and 1740, slightly lagging the Maunder Minimum (1645-1710). A temperature reconstruction, based on the correlation between regional surface temperatures and the stalagmite delta O-18 variations, indicates that parts of this period could have been as much as 1.4 degrees C colder than today. Significant cycles of 22, 11 and 4.8 years demonstrate that the solar magnetic and the El Nino-Southern Oscillation cycle could be important drivers of multidecadal to interannual climate variability in this region. The observation that the most important driver of stalagmite delta O-18 on interannual time scales from this subtropical region is regional surface temperature cautions against deterministic interpretations of delta O-18 variations in low-latitude stalagmites as mainly driven by the amount of precipitation.
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| 36. |
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| 37. |
- Sundqvist, Jesper, et al.
(författare)
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Influence of the metallurgy on fatigue crack propagation in welded high strength steel joints
- 2013
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Ingår i: 14th NOLAMP Conference. - Luleå : Luleå tekniska universitet. - 9789174396881 - 9789174396898 ; , s. 25-35
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Konferensbidrag (refereegranskat)abstract
- A literature study of high strength steels, fatigue and fatigue assessment of welds has beenconducted and is briefly presented in this paper together with experiments on fatigue crackgrowth rates of laser welded high strength steel. It is well-known that the fatigue life ofwelded joints is heavily dependent upon the surface geometry and welding defects because ofcrack initiation from the high stress concentrations associated with these types of weldingflaws. However, the crack propagation through different weld zones of laser-welded highstrength steels and the corresponding impact from the metallurgy is not fully understood.The experiments comprise three-point bending fatigue tests on laser-welded highstrength steel with machined surfaces. Measurement of the fatigue crack propagation ratetransverse the weld and hence through the different metallurgy and hardness of the heataffected zone and of the weld can contain information on the impact of the metallurgy on thecrack propagation speed. The influence of different high strength steel grades and of differentwelding parameters on the crack propagation and fatigue life is discussed
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| 38. |
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| 39. |
- Sundqvist, K.M., et al.
(författare)
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Negative-resistance models for parametrically flux-pumped superconducting quantum interference devices
- 2014
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Ingår i: EPJ Quantum Technology. - : Springer Science and Business Media LLC. - 2196-0763. ; 1:1
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Tidskriftsartikel (refereegranskat)abstract
- A Superconducting QUantum Interference Device (SQUID) modulated by a fast oscillating magnetic flux can be used as a parametric amplifier, providing gain with very little added noise. Here, we develop linearized models to describe the parametrically flux-pumped SQUID in terms of an impedance. An unpumped SQUID acts as an inductance, the Josephson inductance, whereas a flux-pumped SQUID develops an additional, parallel element which we have coined the “pumpistor.” Parametric gain can be understood as a result of a negative resistance of the pumpistor. In the degenerate case, the gain is sensitive to the relative phase between the pump and signal. In the nondegenerate case, gain is independent of this phase.We develop our models first for degenerate parametric pumping in the three-wave and four-wave cases, where the pump frequency is either twice or equal to the signal frequency, respectively. We then derive expressions for the nondegenerate case where the pump frequency is not a multiple of the signal frequency, for which it becomes necessary to consider idler tones that occur. For the nondegenerate three-wave case, we present an intuitive picture for a parametric amplifier containing a flux-pumped SQUID where current at the signal frequency depends upon the load impedance at an idler frequency. This understanding provides insight and readily testable predictions of circuits containing flux-pumped SQUIDs.
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| 40. |
- Sundqvist, Martin, et al.
(författare)
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Little evidence for reversibility of trimethoprim resistance after a drastic reduction in trimethoprim use
- 2010
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Ingår i: Journal of Antimicrobial Chemotherapy. - : Oxford University Press (OUP). - 0305-7453 .- 1460-2091. ; 65:2, s. 350-360
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Tidskriftsartikel (refereegranskat)abstract
- The worldwide rapid increase in antibiotic-resistant bacteria has made efforts to prolong the lifespan of existing antibiotics very important. Antibiotic resistance often confers a fitness cost in the bacterium. Resistance may thus be reversible if antibiotic use is discontinued or reduced. To examine this concept, we performed a 24 month voluntary restriction on the use of trimethoprim-containing drugs in Kronoberg County, Sweden. The intervention was performed on a 14 year baseline of monthly data on trimethoprim resistance and consumption. A three-parameter mathematical model was used to analyse the intervention effect. The prerequisites for reversion of resistance (i.e. fitness cost, associated resistance and clonal composition) were studied on subsets of consecutively collected Escherichia coli from urinary tract infections. The use of trimethoprim-containing drugs decreased by 85% during the intervention. A marginal but statistically significant effect on the increase in trimethoprim resistance was registered. There was no change in the clonal composition of E. coli and there was no measurable fitness cost associated with trimethoprim resistance in clinical isolates. The frequency of associated antibiotic resistances in trimethoprim-resistant isolates was high. A lack of detectable fitness cost of trimethoprim resistance in vitro together with a strong co-selection of other antibiotics could explain the rather disappointing effect of the intervention. The result emphasizes the low possibility of reverting antibiotic resistance once established and the urgent need for the development of new antibacterial agents.
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| 41. |
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| 42. |
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| 43. |
- Ökvist, Lena Sundqvist., et al.
(författare)
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Injection of alternative carbon containing materials into the blast furnace
- 2012
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Ingår i: TMS Annual Meeting. - 9781118291160 ; , s. 161-169
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Konferensbidrag (refereegranskat)abstract
- Residual materials from the integrated steel plant itself or other sources often contain valuable compounds of e.g. C and Fe. Dust and sludge have to be agglomerated to be able to recycle to the blast furnace (BF) via top-charging. By injection of the materials, preparation methods in terms of e.g. drying and/or screening only, can be used. Alternative carbon materials (ACM) in terms of BF dust and sludge have been successfully injected up to levels of 60 kg/tHM in the LKAB Experimental Blast Furnace (LKAB EBF®). Efficiency in recovery of valuable compounds as well as the behavior of undesired elements have been evaluated and are discussed.
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