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| 2. |
- Sator, Lea, et al.
(författare)
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Overdiagnosis of COPD in Subjects With Unobstructed Spirometry A BOLD Analysis
- 2019
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Ingår i: Chest. - : Elsevier BV. - 0012-3692 .- 1931-3543. ; 156:2, s. 277-288
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: There are several reports on underdiagnosis of COPD, while little is known about COPD overdiagnosis and overtreatment. We describe the overdiagnosis and the prevalence of spirometrically defined false positive COPD, as well as their relationship with overtreatment across 23 population samples in 20 countries participating in the BOLD Study between 2003 and 2012.METHODS: A false positive diagnosis of COPD was considered when participants reported a doctor's diagnosis of COPD, but postbronchodilator spirometry was unobstructed (FEV1/FVC > LLN). Additional analyses were performed using the fixed ratio criterion (FEV1/FVC < 0.7).RESULTS: Among 16,177 participants, 919 (5.7%) reported a previous medical diagnosis of COPD. Postbronchodilator spirometry was unobstructed in 569 subjects (61.9%): false positive COPD. A similar rate of overdiagnosis was seen when using the fixed ratio criterion (55.3%). In a subgroup analysis excluding participants who reported a diagnosis of "chronic bronchitis" or "emphysema" (n = 220), 37.7% had no airflow limitation. The site-specific prevalence of false positive COPD varied greatly, from 1.9% in low- to middle-income countries to 4.9% in high-income countries. In multivariate analysis, overdiagnosis was more common among women, and was associated with higher education; former and current smoking; the presence of wheeze, cough, and phlegm; and concomitant medical diagnosis of asthma or heart disease. Among the subjects with false positive COPD, 45.7% reported current use of respiratory medication. Excluding patients with reported asthma, 34.4% of those with normal spirometry still used a respiratory medication.CONCLUSIONS: False positive COPD is frequent. This might expose nonobstructed subjects to possible adverse effects of respiratory medication.
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| 3. |
- Studnicka, Michael, et al.
(författare)
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COPD : Should Diagnosis Match Physiology?
- 2020
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Ingår i: Chest. - : Elsevier BV. - 0012-3692 .- 1931-3543. ; 157:2, s. 473-475
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Zhou, Qiming, et al.
(författare)
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Estimating surface flow paths on a digital elevation model using a triangular facet network
- 2011
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Ingår i: Water Resources Research. - 0043-1397. ; 47, s. 07522-07522
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Tidskriftsartikel (refereegranskat)abstract
- This study attempts to develop a method for the simulation of surface flow paths on a digital elevation model (DEM). The objective is to use a facet-based algorithm to estimate the surface flow paths on a raster DEM. A grid DEM was used to create a triangular facet network (TFN) over which the surface flow paths were determined. Since each facet in the network has a constant slope and aspect, the estimations of, for example, flow direction and divergence/convergence are less complicated compared to traditional raster-based solutions. Experiments were undertaken by estimating the specific catchment area (SCA) over a number of mathematical surfaces, as well as on a real-world DEM. Comparisons were made between the derived SCA by the TFN algorithm with some algorithms reported in the literature. The results show that the TFN algorithm produced the closest outcomes to the theoretical values of the SCA compared with other algorithms, deriving more consistent outcomes and being less influenced by surface shapes. The real-world DEM test also shows that the TFN was capable of modeling flow distribution without noticeable "artifacts," and its ability of tracking flow paths makes it an appropriate platform for dynamic surface flow simulation.
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| 5. |
- Zhou, Shuai, et al.
(författare)
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The calculation of InGaN quantum dot formation mechanism on GaN pyramid
- 2015
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Ingår i: Superlattices and Microstructures. - : Elsevier. - 0749-6036 .- 1096-3677. ; 84, s. 72-79
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Tidskriftsartikel (refereegranskat)abstract
- An equilibrium approach is used to calculate the free energy and composition distribution of InGaN/GaN quantum dot located on the InGaN/GaN pyramid. The energy balance method is adopted to predict critical conditions for quantum dot formation. We find that the formation of QD depends strongly on the size of pyramid top surface. The results can fit our experiment qualitatively.
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