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- Appelberg, Jonas, 1964-, et al.
(författare)
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Lung aeration during sleep in patients with obstructive sleep apnoea
- 2010
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Ingår i: Clinical Physiology and Functional Imaging. - Oxford : Blackwell Publishing. - 1475-0961 .- 1475-097X. ; 30:4, s. 301-307
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Tidskriftsartikel (refereegranskat)abstract
- P>Background: Previous studies have indicated that patients with obstructive sleep apnoea (OSA) have altered ventilation and lung volumes awake and the results suggest that this may be a determinant of severity of desaturations during sleep. However, little is known about regional lung aeration during sleep in patients with OSA. Methods: Twelve patients with OSA were included in the study. Computed tomography was used to study regional lung aeration during wakefulness and sleep. Lung aeration was calculated in ml gas/g lung tissue in four different regions of interest (ROI1-4), along the border of the lung from ventral to dorsal. Results: Lung aeration in the dorsal (dependent) lung region (ROI4) was lower during sleep compared to wakefulness 0 center dot 78 +/- 0 center dot 19 versus 0 center dot 88 +/- 0 center dot 19 (mean +/- SD) ml gas/g lung tissue (P = 0 center dot 005). Associations were found between awake expiratory reserve volume and change in lung aeration from wakefulness to sleep in ROI4 (r = -0 center dot 69; P = 0 center dot 012). In addition, the change in lung aeration in the dorsal region correlated to sleep time (r = 0 center dot 69; P = 0 center dot 014) but not to time in supine position. The difference in lung aeration between inspiration and expiration (i.e. ventilation), was larger in the ventral lung region when expressed as ml gas per g lung tissue. In two patients it was noted that, during on-going obstructive apnoea, lung aeration tended to be increased rather than decreased. Conclusions: Aeration in the dorsal lung region is reduced during sleep in patients with OSA. The decrease is related to lung volume awake and to sleep time.
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| 2. |
- Osterman, J., et al.
(författare)
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Scanning spreading resistance microscopy of aluminum implanted 4H-SiC
- 2003
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Ingår i: Materials Science & Engineering. - 0921-5107 .- 1873-4944. ; 102:1-3, s. 128-131
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Results from the application of scanning spreading resistance microscopy (SSRM) for characterization of aluminum implanted 4H-SiC are presented. The implanted profiles are investigated electrically and morphologically as a function of post-implantation anneal conditions. The method is shown to be advantageous for measuring and optimizing the activation in many aspects with respect to existing alternative techniques: it provides information of the entire depth and Al concentration range, it is unaffected by annealing induced re-growth and/or surface roughening, and requires little sample preparation. The results indicate that the apparent activation and surface roughness do not saturate in the investigated temperature range of 1500-1650 °C. Finally, an apparent activation energy for the process of 3 eV is estimated. © 2003 Elsevier B.V. All rights reserved.
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