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| 2. |
- Hergens, Maria-Pia, et al.
(författare)
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Use of Scandinavian Moist Smokeless Tobacco (Snus) and the Risk of Atrial Fibrillation
- 2014
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Ingår i: Epidemiology. - 1044-3983 .- 1531-5487. ; 25:6, s. 872-876
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Snus is a smokeless tobacco product, widely used among Swedish men and increasingly so elsewhere. There is debate as to whether snus is an acceptable "harm-reduction" tobacco product. Since snus use delivers a dose of nicotine equivalent to cigarettes, and has been implicated in cardiac arrhythmia because of associations with sudden cardiovascular death, a relation with atrial fibrillation is plausible and important to investigate.METHODS:: To assess the relation between use of snus and risk of atrial fibrillation, we carried out a pooled analysis of 7 prospective Swedish cohort studies. In total, 274,882 men, recruited between 1978 and 2004, were followed via the National Patient Register for atrial fibrillation. Primary analyses were restricted to 127,907 never-smokers. Relative risks were estimated using Cox proportional hazard regression.RESULTS:: The prevalence of snus use was 25% among never-smokers. During follow-up, 3,069 cases of atrial fibrillation were identified. The pooled relative risk of atrial fibrillation was 1.07 (95% confidence interval = 0.97-1.19) in current snus users, compared with nonusers.CONCLUSION:: Findings from this large national pooling project indicate that snus use is unlikely to confer any important increase in risk of atrial fibrillation.
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| 3. |
- Odell, Anders, 1979-
(författare)
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Quantum transport in photoswitching molecules : An investigation based on ab initio calculations and Non Equilibrium Green Function theory
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Molecular electronics is envisioned as a possible next step in device miniaturization. It is usually taken to mean the design and manufacturing of electronic devices and applications where organic molecules work as the fundamental functioning unit. It involves the easurement and manipulation of electronic response and transport in molecules attached to conducting leads. Organic molecules have the advantages over conventional solid state electronics of inherent small sizes, endless chemical diversity and ambient temperature low cost manufacturing. In this thesis we investigate the switching and conducting properties of photochromic dithienylethene derivatives. Such molecules change their conformation in solution when acted upon by light. Photochromic molecules are attractive candidates for use in molecular electronics because of the switching between different states with different conducting properties. The possibility of optically controlling the conductance of the molecule attached to leads may lead to new device implementations. The switching reaction is investigated with potential energy calculations for different values of the reaction coordinate between the closed and the open isomer. The electronic and atomic structure calculations are performed with density functional theory (DFT). It is concluded that there is a large potential energy barrier separating the open and closed isomer and that switching between open and closed forms must involve excited states. The conducting properties of the molecule inserted between gold leads is calculated within the Non Equilibrium Green Function theory. The transmission function is calculated for the two isomers with different basis sizes for the gold contacts, as well as the electrostatic potential, for finite applied bias voltages. We conclude that a Au 6s basis give qualitatively the same result as a Au spd basis close to the Fermi level. The transmission coefficient at the Fermi energy is around 10 times larger in the closed molecule compared to the open. This will result in a large difference in conductivity. It is also found that the large difference in conductivity will remain for small applied bias voltages. The results are consistent with earlier work.
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| 4. |
- Ruber, Roger, et al.
(författare)
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Accelerator development at the FREIA Laboratory
- 2021
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Ingår i: Journal of Instrumentation. - : Institute of Physics Publishing (IOPP). - 1748-0221. ; 16:7
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Tidskriftsartikel (refereegranskat)abstract
- The FREIA Laboratory at Uppsala University focuses on superconducting technology and accelerator development. It actively supports the development of the European Spallation Source, CERN, and MAX IV, among others. FREIA has developed test facilities for superconducting accelerator technology such as a double-cavity horizontal test cryostat, a vertical cryostat with a novel magnetic field compensation scheme, and a test stand for short cryomodules. Accelerating cavities have been tested in the horizontal cryostat, crab-cavities cavities in the vertical cryostat, and cryomodules for ESS on the cryomodule test stand. High power radio-frequency amplifier prototypes based on vacuum tube technology were developed for driving spoke cavities. Solid-state amplifiers and power combiners are under development for future projects. We present the status of the FREIA Laboratory complemented with results of recent projects and future prospects.
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| 5. |
- Sundström, Johan, Professor, 1971-, et al.
(författare)
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Risk factors for subarachnoid haemorrhage : a nationwide cohort of 950 000 adults
- 2019
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Ingår i: International Journal of Epidemiology. - : Oxford University Press. - 0300-5771 .- 1464-3685. ; 48:6, s. 2018-2025
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Subarachnoid haemorrhage (SAH) is a devastating disease, with high mortality rate and substantial disability among survivors. Its causes are poorly understood. We aimed to investigate risk factors for SAH using a novel nationwide cohort consortium.METHODS: We obtained individual participant data of 949 683 persons (330 334 women) between 25 and 90 years old, with no history of SAH at baseline, from 21 population-based cohorts. Outcomes were obtained from the Swedish Patient and Causes of Death Registries.RESULTS: During 13 704 959 person-years of follow-up, 2659 cases of first-ever fatal or non-fatal SAH occurred, with an age-standardized incidence rate of 9.0 [95% confidence interval (CI) (7.4-10.6)/100 000 person-years] in men and 13.8 [(11.4-16.2)/100 000 person-years] in women. The incidence rate increased exponentially with higher age. In multivariable-adjusted Poisson models, marked sex interactions for current smoking and body mass index (BMI) were observed. Current smoking conferred a rate ratio (RR) of 2.24 (95% CI 1.95-2.57) in women and 1.62 (1.47-1.79) in men. One standard deviation higher BMI was associated with an RR of 0.86 (0.81-0.92) in women and 1.02 (0.96-1.08) in men. Higher blood pressure and lower education level were also associated with higher risk of SAH.CONCLUSIONS: The risk of SAH is 45% higher in women than in men, with substantial sex differences in risk factor strengths. In particular, a markedly stronger adverse effect of smoking in women may motivate targeted public health initiatives.
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| 6. |
- Wallensten, Anders, et al.
(författare)
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Surveillance of influenza A virus in migratory waterfowl in northern Europe
- 2007
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Ingår i: Emerging Infectious Diseases. - 1080-6040 .- 1080-6059. - 1080-6040 ; 13:3, s. 404-411
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Tidskriftsartikel (refereegranskat)abstract
- We conducted large-scale, systematic sampling of influenza type A virus in migratory waterfowl (mostly mallards [Anas platyrhynchos]) at Ottenby Bird Observatory, southeast Sweden. As with previous studies, we found a higher prevalence in fall than spring, and among juveniles compared with adults. However, in contrast to other studies, we found that prevalence in spring was sometimes high (mean 4.0%, highest 9.5%). This finding raises the possibility that ducks are capable of perpetuating influenza A virus of different subtypes and subtype combinations throughout the year and from 1 year to the next. Isolation of the H5 and H7 subtypes was common, which suggests risk for transmission to sensitive domestic animals such as poultry. We argue that wild bird screening can function as a sentinel system, and we give an example of how it could have been used to forecast a remote and deadly outbreak of influenza A in poultry.
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| 7. |
- Wang, Chunliang, 1980-, et al.
(författare)
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Can segmented 3D images be used for stenosis evaluation in coronary CT angiography?
- 2012
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Ingår i: Acta Radiologica. - : Sage Publications. - 0284-1851 .- 1600-0455. ; 53:8, s. 845-851
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Tidskriftsartikel (refereegranskat)abstract
- Background: Thanks to the development of computed tomography (CT) scanners and computer software, accurate coronary artery segmentation can be achieved with minimum user interaction. However, the question remains whether we can use these segmented images for reliable diagnosis. Purpose: To retrospectively evaluate the diagnostic accuracy of coronary CT angiography (CCTA) using segmented 3D data for the detection of significant stenosis. Material and Methods: CCTA data-sets from 30 patients were acquired with a 64-slice CT scanner and segmented using the region growing (RG) method and the "virtual contrast injection" (VC) method. Three types of images of each patient were reviewed by different reviewers for the presence of stenosis with diameter reduction of 50% or more. The evaluation was performed on four main arteries of each patient (120 arteries in total). For the original series, the reviewer was allowed to use all the 2D and 3D visualization tools available (conventional method). For the segmented results from RG and VC, only maximum intensity projection was used. Evaluation results were compared with catheter angiography (CA) for each artery in a blinded fashion. Results: Overall, 34 arteries with significant stenosis were identified by CA. The percentage of evaluable arteries, accuracy and negative predictive value for detecting stenosis were, respectively, 86%, 74%, and 93% for the conventional method, 83%, 71%, and 92% for VC, and 64%, 56%, and 93% for RG. Accuracy was significantly lower for the RG method than for the other two methods (P < 0.01), whereas there was no significant difference in accuracy between the VC method and the conventional method (P = 0.22). Conclusion: The diagnostic accuracy for the RG-segmented 3D data is lower than those with access to 2D images, whereas the VC method shows diagnostic accuracy similar to the conventional method.
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| 9. |
- Abrahamsson, Katarina, 1957, et al.
(författare)
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Variations of biochemical parameters along a transect in the Southern Ocean, with special emphasis on volatile halogenated organic compounds
- 2004
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Ingår i: Deep-sea research. Part II, Topical studies in oceanography. - : Elsevier BV. - 0967-0645. ; 51:22-24, s. 2745-2756
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Tidskriftsartikel (refereegranskat)abstract
- A number of parameters of biogeochemical interest were monitored along a north-southerly transect (S 43-S 63degrees) in the Atlantic Sector of the Southern Ocean from the 8th to the 20th of December 1997. Changes in total dissolved inorganic carbon (C-T) and total alkalinity (A(T)) were mostly dependent on temperature and salinity until the ice edge was reached. After this point only a weak correlation was seen between these. Highest mean values of C-T and A(T) were observed in the Winter Ice Edge (WIE) (2195 and 2319 mumol kg(-1), respectively). Lowest mean AT (2277 mumol kg(-1)) was observed in the Sub-Antarctic Front (SAF), whereas lowest mean CT concentration (2068 mumol kg(-1)) was associated with the Sub-Tropical Front (STF). The pH in situ varied between 8.060 and 8.156 where the highest values were observed in the southern part of the Antarctic Polar Front (APF) and in the Summer Ice Edge (SIE) Region. These peaks were associated with areas of high chlorophyll a (chl a) and tribromomethane values. In the other areas the pH in situ was mainly dependent on hydrography. Bacterial abundance decreased more than one order of magnitude when going from north to south. The decrease appeared to be strongly related to water temperature and there were no elevated abundances at frontal zones. Microphytoplankton dominated in the SAF and APF, whereas the nano- and picoplankton dominated outside these regions. Volatile halogenated compounds were found to vary both with regions, and with daylight. For the iodinated compounds, the highest concentrations were found north of the STF. Brominated hydrocarbons had high concentrations in the STF, but elevated concentrations were also found in the APF and SIE regions. No obvious correlation could be found between the occurrence of individual halocarbons and chl a. On some occasions trichloroethene and tribromomethane related to the presence of nano- and microplankton, respectively.
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| 10. |
- Ahonen, Hanna, et al.
(författare)
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Applying World Dental Federation Theoretical Framework for Oral Health in a General Population
- 2021
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Ingår i: International Dental Journal. - : Elsevier. - 0020-6539 .- 1875-595X. ; 72:4, s. 536-544
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The World Dental Federation (FDI) has recently proposed a new definition and theoretical framework of oral health. The theoretical framework includes 4 main components and describes the relationships amongst them. In 2020, an international work group proposed the minimum Adult Oral Health Standard Set (AOHSS) of variables to measure oral health, which was mapped onto the FDI's theoretical framework. By using an empirical data set, the proposed variables in the AOHSS and the potential interactions amongst the components of the FDI's theoretical framework can be tested. The purpose of this research was to investigate structural relations of the components of the FDI's theoretical framework of oral health based on data from a general adult population. Methods: Data from a previously conducted Swedish cross-sectional study focusing on oral health were utilised (N = 630; women, 55.2%; mean age, 49.7 years [SD, 19.2]). Variable selection was guided by the AOHSS. Structural equation modeling was used to analyse relationships amongst the components of the FDI's theoretical model (core elements of oral health, driving determinants, moderating factors, and overall health and well-being). Results: The Oral Health Impact Profile (OHIP)-14, xerostomia, and aesthetic satisfaction had statistically significant direct effects on overall health and well-being (p < .05). Driving determinants and moderating factors had statistically significant direct effects on all core elements of oral health (p < .05) except aesthetic satisfaction (p = .616). The predictors explained 24.1% of the variance of the latent variable overall health and well-being. Based on several indices, the proposed model showed acceptable model fit. Conclusions: The FDI's theoretical framework can be used to describe different components of oral health and the relationship amongst them in an adult general population. Further research based on the FDI's theoretical framework in other populations and settings is needed to explore complex interactions and possible relationships that form oral health and to investigate other or additional important social determinants.
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