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- Lundgren, Pia, 1967, et al.
(författare)
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National cohort of infants born before 24 gestational weeks showed increased survival rates but no improvement in neonatal morbidity
- 2022
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 111:8, s. 1515-1525
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Tidskriftsartikel (refereegranskat)abstract
- Aim To describe survival and neonatal morbidities in infants born before 24 weeks of gestation during a 12-year period. Methods Data were retrieved from national registries and validated in medical files of infants born before 24 weeks of gestation 2007-2018 in Sweden. Temporal changes were evaluated. Results In 2007-2018, 282 live births were recorded at 22 weeks and 460 at 23 weeks of gestation. Survival to discharge from hospital of infants born alive at 22 and 23 weeks increased from 20% to 38% (p = 0.006) and from 45% to 67% (p < 0.001) respectively. Caesarean section increased from 12% to 22% (p = 0.038) for infants born at 22 weeks. Neonatal morbidity rates in infants alive at 40 weeks of postmenstrual age (n = 399) were unchanged except for an increase in necrotising enterocolitis from 0 to 33% (p = 0.017) in infants born at 22 weeks of gestation. Bronchopulmonary dysplasia was more common in boys than girls, 90% versus 82% (p = 0.044). The number of infants surviving to 40 weeks doubled over time. Conclusion Increased survival of infants born before 24 weeks of gestation resulted in increasing numbers of very immature infants with severe neonatal morbidities likely to have a negative impact on long-term outcome.
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- Morsing, Eva, et al.
(författare)
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Neurodevelopmental disorders and somatic diagnoses in a national cohort of children born before 24 weeks of gestation
- 2022
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Ingår i: Acta Paediatrica, International Journal of Paediatrics. - : Wiley. - 0803-5253 .- 1651-2227. ; 111:6, s. 1167-1175
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Tidskriftsartikel (refereegranskat)abstract
- Aim: This study investigated childhood diagnoses in children born extremely preterm before 24 weeks of gestation. Methods: Diagnoses of neurodevelopmental disorders and selected somatic diagnoses were retrospectively retrieved from national Swedish registries for children born before 24 weeks from 2007 to 2018. Their individual medical files were also examined. Results: We studied 383 children born at a median of 23.3 (range 21.9–23.9) weeks, with a median birthweight of 565 (range 340–874) grams. Three-quarters (75%) had neurodevelopmental disorders, including speech disorders (52%), intellectual disabilities (40%), attention deficit hyperactivity disorder (30%), autism spectrum disorders (24%), visual impairment (22%), cerebral palsy (17%), epilepsy (10%) and hearing impairment (5%). More boys than girls born at 23 weeks had intellectual disabilities (45% vs. 27%, p < 0.01) and visual impairment (25% vs. 14%, p < 0.01). Just over half of the cohort (55%) received habilitation care. The majority (88%) had somatic diagnoses, including asthma (63%) and failure to thrive/short stature (39%). Conclusion: Most children born before 24 weeks had neurodevelopmental disorders and/or additional somatic diagnoses in childhood and were referred to habilitation services. Clinicians should be aware of the multiple health and developmental problems affecting these children. Resources are needed to identify their long-term support needs at an early stage.
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- Morsing, Eva, et al.
(författare)
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[Survival and prematurity-related neonatal diagnoses among children born before 24 gestational weeks in Sweden 2007-2018]. : Allt fler barn födda före vecka 24 överlever, men sjukligheten är hög.
- 2023
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Ingår i: Lakartidningen. - 1652-7518. ; 120:10-11
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Tidskriftsartikel (refereegranskat)abstract
- Children born before 24 gestational weeks had high neonatal morbidity and a majority had one or more neurodevelopmental disorders in addition to somatic diagnoses in childhood. Active Swedish perinatal care of infants with gestational age <24 weeks has resulted in a survival rate of more than 50 percent. Resuscitation of these immature infants is controversial, and some countries offer comfort care only. In a retrospective review of medical files and registries of 399 Swedish infants born before 24 gestational weeks, a majority had severe prematurity-related neonatal diagnoses. In childhood (2-13 years), 75 percent had at least one neurodevelopmental disorder and 88 percent had one or more prematurity-related somatic diagnosis (permanent or transient) that was likely to affect their quality of life. Long-term consequences for surviving infants should be considered in general recommendations as well as in parental information.
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- Andersson, Anders, et al.
(författare)
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Describing fish passage in a river confluence with telemetry and CFD
- 2016
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Konferensbidrag (refereegranskat)abstract
- The confluence between hydropower tailrace and the old river bed in Stornorrfors in the river Umeälven in the northern part of Sweden has shown to be the largest obstacle for upstream migrating salmon and sea trout during the migrating season. Fish are attracted to the high flow rate from the tailrace and will not migrate upstream in the old river bed being the passage to the fishway leading past the hydropower dam. By triangulating the movements of radio tagged fish using eight antennas in the confluence, it is here possible to describe the individual fish tracks left by radio tagged fish during the migrating season. These tracks are then compared with three-dimensional Computational Fluid Dynamics (CFD) simulations of the confluence. By simulating the most common combinations of turbine flow and spill flow in the old river bed it is then possible to find correlations between individual fish movements and flow parameters such as velocity, turbulence intensity or vorticity for different flow combinations. It was previously assumed that fish had trouble locating the old river bed, the results of the triangulation however shows that most fish finds the old river bed within a few days but does not chose to migrate until several days (or weeks) later. The main issue to be solved is therefore not how to attract the fish to the old river bed but rather how to create favorable conditions in the old river bed so that migrating fish are more inclined to take that path upstream.
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- Andersson, Anders G., et al.
(författare)
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Effect of spatial resolution of rough surfaces on numerically computed flow fields with application to hydraulic engineering
- 2014
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Ingår i: Engineering Applications of Computational Fluid Mechanics. - : Informa UK Limited. - 1994-2060 .- 1997-003X. ; 8:3, s. 373-381
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Tidskriftsartikel (refereegranskat)abstract
- In numerical simulations of flow over rough surfaces, the roughness is often not resolved but represented by a numerical model. The validity of such an assumption is investigated in this paper by Reynolds-Averaged Navier-Stokes simulations of flow over a surface with a large roughness. The surface was created from a high-resolution laser scanning of a real rock blasted tunnel. By reducing the geometrical resolution of the roughness in two steps, the importance of an appropriate surface description could be examined. The flow fields obtained were compared to a set-up with a geometrical flat surface where the roughness was represented by a modified form of the Launder and Spalding wall-function. The flow field over the surface with the lowest resolution was substantially different from those of the two finer resolutions and rather close to the results from the set-up with the wall-function. The results also yield that the finer the resolution is the more vorticity is formed close to the rough surface and more turbulence is generated.
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- Andersson, L. Robin, et al.
(författare)
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Characterization of Flow Structures Induced by Highly Rough Surface Using Particle Image Velocimetry, Proper Orthogonal Decomposition and Velocity Correlations
- 2018
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Ingår i: Engineering. - : Scientific Research Publishing. - 1947-3931 .- 1947-394X. ; 10, s. 399-416
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Tidskriftsartikel (refereegranskat)abstract
- High Reynolds number flow inside a channel of rectangular cross section is examined using Particle Image Velocimetry. One wall of the channel has been replaced with a surface of a roughness representative to that of real hydropower tunnels, i.e. a random terrain with roughness dimensions typically in the range of ≈10% - 20% of the channels hydraulic radius. The rest of the channel walls can be considered smooth. The rough surface was captured from an existing blasted rock tunnel using high resolution laser scanning and scaled to 1:10. For quantification of the size of the largest flow structures, integral length scales are derived from the auto-correlation functions of the temporally averaged velocity. Additionally, Proper Orthogonal Decomposition (POD) and higher-order statistics are applied to the instantaneous snapshots of the velocity fluctuations. The results show a high spatial heterogeneity of the velocity and other flow characteristics in vicinity of the rough surface, putting outer similarity treatment into jeopardy. Roughness effects are not confined to the vicinity of the rough surface but can be seen in the outer flow throughout the channel, indicating a different behavior than postulated by Townsend’s similarity hypothesis. The effects on the flow structures vary depending on the shape and size of the roughness elements leading to a high spatial dependence of the flow above the rough surface. Hence, any spatial averaging, e.g. assuming a characteristic sand grain roughness factor, for determining local flow parameters becomes less applicable in this case.
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