| 1. |
- Hager, Jakob, 1967-
(författare)
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Abdominal Aortic Aneurysm : Aspects on how to affect mortality from rupture
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Abdominal Aortic Aneurysm (AAA) is a disease that mainly affects elderly men, and ruptured AAA (rAAA) is associated with a mortality of > 80%. AAA seldom gives any symptoms prior to rupture.The aims of this thesis were to investigate different aspects of how to affect mortality from rAAA.In Study I, we identified 849 patients treated for rAAA during 1987-2004, and studied the 30-day survival after surgery, depending on whether they came directly to the treating hospital (one-stop) or were transferred via another hospital (two-stop). A two-stop referral pattern resulted in a 27% lower population-based survival rate for patients 65-74 years of age. However, the consequences would be small even if a one-stop referral pattern could be generally accomplished, due to the huge over-all mortality related to rAAA, hence an argument to find and treat AAA before rupture, e.g. by screening.In Study II, we examined the AAA-prevalence and the risk factors for AAA among 70-year-old men. The screening-detected AAA-prevalence was 2.3%, thus less than half the predicted. The most important risk factor was smoking.In Study III, we compared the screening-detected AAA-prevalence, the attendance rate, and the rate of opportunistic detection of AAA, between almost 8000 65- and 6000 70-year-old men. There was no difference in the screening-detected prevalence; probably due to the fact that almost 40% of the AAAs among the 70-year-old were already known prior to screening, compared to roughly 25% in the 65-year-old. The attendance rate was higher among the 65-year-old men, 85.7% compared 84.0% in the 70-year-old. Thus, there is no benefit of screening for AAA among 70- instead of 65-year-old men.In Study IV, a cost-effectiveness analysis, we found that screening for AAA still appears to be cost-effective, despite profound changes in disease pattern and AAA-management.In conclusion, we found that mortality from rAAA is not affected in any substantial way by different referral patterns and hence centralisation of services for AAA/rAAA is not a solution. A better alternative is to prevent rupture through early detection by screening. Screening 65-year-old men for AAA still appears to be cost-effective, despite profound changes in disease pattern and AAA-management during the last decade. Screening 70- instead of 65-year-old men will not increase the efficacy of screening.
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| 2. |
- Hager, Jakob, et al.
(författare)
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Changing Conditions - the same Conclusion : Cost-effective to Screen for Abdominal Aortic Aneurysm among 65-year-old Men, based on Data from an Implemented Screening Programme
- 2014
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background: Health economic analyses based on randomized trials have shown that screening for abdominal aortic aneurysm (AAA) cost-effectively decreases AAA-related as well as allcause mortality. However, results from running screening programmes now reveal substantially changed conditions in terms of prevalence, attendance rate, costs and mortality after intervention. Our aim was to evaluate whether screening for AAA among 65-year-old men on a general basis is cost-effective under current clinical practice.Methods: A decision-analytic model, previously used to show the cost-effectiveness of an AAA-screening programme before decision to introduce screening in practice, was updated using results from implemented screening-programmes as well as data from contemporary published data and the Swedvasc registry.Results: The base-case analysis showed that the cost per life-year gained and quality-adjusted life year (QALY) gained were 3252 € and 4231 €, respectively. The probability of screening being cost-effective was high.Conclusion: Despite profound changes in disease pattern and AAA-management, the current results are similar to those reported almost 10 years ago, and thus screening 65-year-old men for AAA still appears to be cost-effective.
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| 3. |
- Hager, Jakob, et al.
(författare)
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Lower Prevalence than Expected when Screening 70-year-old Men for Abdominal Aortic Aneurysm
- 2013
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1078-5884 .- 1532-2165. ; 46:4, s. 453-459
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundScreening 65-year-old men for abdominal aortic aneurysms (AAA) is a cost-effective method to reduce the mortality from ruptured AAA. However, contemporary results show a lower than expected prevalence of AAA, thus questioning the benefit of screening. Since the prevalence increases with age, a possible way to enhance the benefit of screening might be to screen older men. Our aim was to determine the contemporary screening-detected prevalence among 70-year-old men.MethodsA total of 5,623 unscreened 70-year-old men were invited to ultrasound screening. Uni- and multivariable analyses were used to assess the risk factors for AAA.ResultsThe attendance rate was 84.0%. The prevalence of previously unknown AAAs was 2.3%. When adding the 64 men with an already known AAA to the screening-detected ones, the total prevalence in the population was at least 3.0%, and the previously discovered AAAs constituted 37.4% of the total prevalence. “Ex smoker” and “Current smoker” were the most important risk factors.ConclusionsWhen screening 70-year-old men for AAA, the prevalence was less than half that expected, despite a high attendance rate. Smoking was the strongest risk factor. Almost 40% of the men with AAAs were already known from other means than screening.
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| 4. |
- Hager, Jakob, et al.
(författare)
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No benefit of screening for abdominal aortic aneurysm among 70- instead of 65-year-old men
- 2014
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Ingår i: International Angiology. - : EDIZIONI MINERVA MEDICA. - 0392-9590. ; 33:5, s. 474-479
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Screening 65-year-old men for abdominal aortic aneurysm (AAA) reduces mortality from ruptured AAA (rAAA). Lower than expected prevalence of AAA is now found, why screening at a higher age and rescreening has been discussed. Our aim was to determine if screening at 70 years of age, instead of 65, increases clinical effectiveness.Methods: 7951 and 5623 previously un-screened 65- and 70-year old men were invited to ultrasound screening.Results: The attendance rate was 85.7% and 84.0%, p<0.01, for the 65- and 70-year old men respectively. The screening-detected prevalence did not differ, being 1.9% and 2.3%, p=0.15, respectively, probably due to the fact that 23.5% and 37.4% of all known AAA among 65- and 70-year-old men, were detected by other means prior to screening, p<0.01. However, the total known prevalence differed between the age-groups, being at least 2.1% and 3.0% respectively, p<0.001.Conclusion: The screening-detected AAA-prevalence did not differ between 65- and 70-yearold men, due to the greater number of AAA known prior to screening among 70- compared to 65-year-old men. Screening men at 70 instead of 65 years of age would not result in detection of substantially more previously unknown AAA, thus not preventing rAAA and consequently not more saved life-years. Further, data also indicates that it is questionable if re-screening the 65-year-old male population after five years would generate any important clinical effect.
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| 5. |
- Hantke, Max F., et al.
(författare)
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High-throughput imaging of heterogeneous cell organelles with an X-ray laser
- 2014
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Ingår i: Nature Photonics. - : Springer Science and Business Media LLC. - 1749-4885 .- 1749-4893. ; 8:12, s. 943-949
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Tidskriftsartikel (refereegranskat)abstract
- We overcome two of the most daunting challenges in single-particle diffractive imaging: collecting many high-quality diffraction patterns on a small amount of sample and separating components from mixed samples. We demonstrate this on carboxysomes, which are polyhedral cell organelles that vary in size and facilitate up to 40% of Earth's carbon fixation. A new aerosol sample-injector allowed us to record 70,000 low-noise diffraction patterns in 12 min with the Linac Coherent Light Source running at 120 Hz. We separate different structures directly from the diffraction data and show that the size distribution is preserved during sample delivery. We automate phase retrieval and avoid reconstruction artefacts caused by missing modes. We attain the highest-resolution reconstructions on the smallest single biological objects imaged with an X-ray laser to date. These advances lay the foundations for accurate, high-throughput structure determination by flash-diffractive imaging and offer a means to study structure and structural heterogeneity in biology and elsewhere.
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| 6. |
- Nordin, E. Z., et al.
(författare)
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Secondary organic aerosol formation from gasoline passenger vehicle emissions investigated in a smog chamber
- 2012
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Ingår i: Atmospheric Chemistry and Physics Discussions. - : Copernicus Publications. - 1680-7367 .- 1680-7375. ; 12:12, s. 31725-31765
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Tidskriftsartikel (refereegranskat)abstract
- Gasoline vehicles have elevated emissions of volatile organic compounds during cold starts and idling and have recently been pointed out as potentially the main source of anthropogenic secondary organic aerosol (SOA) in megacities. However, there is a lack of laboratory studies to systematically investigate SOA formation in real-world exhaust. In this study, SOA formation from pure aromatic precursors, idling and cold start gasoline exhaust from one Euro II, one Euro III and one Euro IV passenger vehicles were investigated using photo-oxidation experiments in a 6 m3 smog chamber. The experiments were carried out at atmospherically relevant organic aerosol mass concentrations. The characterization methods included a high resolution aerosol mass spectrometer and a proton transfer mass spectrometer. It was found that gasoline exhaust readily forms SOA with a signature aerosol mass spectrum similar to the oxidized organic aerosol that commonly dominates the organic aerosol mass spectra downwind urban areas. After 4 h aging the formed SOA was 1–2 orders of magnitude higher than the Primary OA emissions. The SOA mass spectrum from a relevant mixture of traditional light aromatic precursors gave f43 (mass fraction at m/z = 4 3) approximately two times higher than to the gasoline SOA. However O : C and H : C ratios were similar for the two cases. Classical C6–C9 light aromatic precursors were responsible for up to 60% of the formed SOA, which is significantly higher than for diesel exhaust. Important candidates for additional precursors are higher order aromatic compounds such as C10, C11 light aromatics, naphthalene and methyl-naphthalenes.
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| 7. |
- Rath, Asawari D., et al.
(författare)
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Explosion dynamics of sucrose nanospheres monitored by time of flight spectrometry and coherent diffractive imaging at the split-and-delay beam line of the FLASH soft X-ray laser
- 2014
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Ingår i: Optics Express. - 1094-4087. ; 22:23, s. 28914-28925
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Tidskriftsartikel (refereegranskat)abstract
- We use a Mach-Zehnder type autocorrelator to split and delay XUV pulses from the FLASH soft X-ray laser for triggering and subsequently probing the explosion of aerosolised sugar balls. FLASH was running at 182 eV photon energy with pulses of 70 fs duration. The delay between the pump-probe pulses was varied between zero and 5 ps, and the pulses were focused to reach peak intensities above 1016 W/cm2 with an off-axis parabola. The direct pulse triggered the explosion of single aerosolised sucrose nano-particles, while the delayed pulse probed the exploding structure. The ejected ions were measured by ion time of flight spectrometry, and the particle sizes were measured by coherent diffractive imaging. The results show that sucrose particles of 560-1000 nm diameter retain their size for about 500 fs following the first exposure. Significant sample expansion happens between 500 fs and 1 ps. We present simulations to support these observations.
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| 8. |
- Åsberg, Jakob, 1978, et al.
(författare)
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Reading comprehension among typically developing Swedish-speaking 10-12-year-olds: Examining subgroups differentiated in terms of language and decoding skills.
- 2010
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Ingår i: Logopedics, Phoniatrics, Vocology. - : Informa UK Limited. - 1651-2022 .- 1401-5439. ; 35:4, s. 189-193
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Tidskriftsartikel (refereegranskat)abstract
- Based on data from 156 typically developing 10-12-year-olds from Sweden, reading comprehension skills were studied in three subgroups: those classified with specific poor word decoding skills (n = 10), those with specific poor language comprehension (n = 12), and those with mixed difficulties in word decoding and language comprehension (n = 11). The mixed poor group achieved significantly lower scores than both specific groups in reading comprehension, and was the only group displaying poor reading comprehension test results relative to the performance of the full sample. Results are indicative of the necessity of a combined effect of poor word decoding and language in reading comprehension difficulties for this group. Implications and limitations are discussed.
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