| 1. |
- Ekman, Petter, 1988-, et al.
(författare)
-
Accuracy and Speed for Scale-Resolving Simulations of the DrivAer Reference Model
- 2019
-
Ingår i: WCX SAE World Congress Experience. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International.
-
Konferensbidrag (refereegranskat)abstract
- In aerodynamic development of ground vehicles, the use of Computational Fluid Dynamics (CFD) is crucial for improving the aerodynamic performance, stability and comfort of the vehicle. Simulation time and accuracy are two key factors of a well working CFD procedure. Using scale-resolving simulations, accurate predictions of the flow field and aerodynamic forces are possible, but often leads to long simulation time. For a given solver, one of the most significant aspects of the simulation time/cost is the temporal resolution. In this study, this aspect is investigated using the realistic vehicle model DrivAer with the notchback geometry as the test case. To ensure a direct and accurate comparison with wind tunnel measurements, performed at TU Berlin, a large section of the wind tunnel is included in the simulation domain. All simulations are performed at a Reynolds number of 3.12 million, based on the vehicle length. Three spatial resolutions were compared, where it could be seen that a hybrid element mesh consisting of 102 million cells only revealed small differences to the finest mesh investigated, well as showing excellent agreement with wind tunnel measurements. An investigation of the temporal resolution is performed, in order to see its effect on the simulation time/cost and accuracy of the results. The finest temporal resolution resulted in a Courant-Friedrichs-Lewy number less than unity, while the coarsest reached a CFL number of around 100. From these results, it is seen that it is possible to reduce the simulation time with more than 90 % (CFL 20) and still keep sufficient accuracy of the forces and important features of the flow field.
|
|
| 2. |
- Krakau, Karolina, 1968-, et al.
(författare)
-
Energy balance and metabolism after severe traumatic brain injury : A pilot study using doubly labelled water
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Objective: To explore the course of energy balance in patients with severe traumatic brain injury, from time of injury until twelve weeks post injury. Method: This prospective desriptive study included six patients with isolated, closed severe traumatic brain injury and an expected hospital stay of ≥2-3 months. Energy balance was calculated from energy intake compared to total energy expenditure measured by continuous indirect calorimetry and doubly labelled water. Clinical and laboratory variables with possible influence on metabolism and nutritional delivery were recorded simultaneously. Intermittent indirect calorimetry measurements were used to differentiate components of the energy expended. Results: Patients were roughly in energy balance while on mechanical ventilation, but in negative energy balance from the 3rd week post injury. The total energy expenditure then increased while the daily energy intake declined. Concurrent with this period were difficulties in retaining enteral and/or parenteral nutrition delivery routes until oral feeding was satisfactory. Nitrogen balance was back to normal at about 1.5 months and the inflammatory period with increased C-reactive protein levels continued for 12 to 58 days from time of injury. During the first and second month post injury, patients lost 8-19% of their initial body weight. Conclusion: Data suggests that negative energy balance after a severe TBI could not only be explained by the elevated metabolic rate and catabolism induced by the trauma, but also by difficulties in securing alternative nutritional routes in the distressed patient.
|
|
| 3. |
- Moberg, Christina, et al.
(författare)
-
De unga gör helt rätt när de stämmer staten
- 2022
-
Ingår i: Aftonbladet. - 1103-9000.
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
|
|
| 4. |
- Skyllberg, Ulf, et al.
(författare)
-
Net Methylmercury Production as a Basis for Improved Risk Assessment of Mercury-contaminated Sediments
- 2007
-
Ingår i: AMBIO: A Journal of the Human Environment. ; 36:6, s. 437-42
-
Tidskriftsartikel (refereegranskat)abstract
- Sediments contaminated by various sources of mercury (Hg) were studied at 8 sites in Sweden covering wide ranges of climate, salinity, and sediment types. At all sites, biota (plankton, sediment living organisms, and fish) showed enhanced concentrations of Hg relative to corresponding organisms at nearby reference sites. The key process determining the risk at these sites is the net transformation of inorganic Hg to the highly toxic and bioavailable methylmercury (MeHg). Accordingly, Hg concentrations in Perca fluviatilis were more strongly correlated to MeHg (p < 0.05) than to inorganic Hg concentrations in the sediments. At all sites, except one, concentrations of inorganic Hg (2–55 μg g−1) in sediments were significantly, positively correlated to the concentration of MeHg (4–90 ng g−1). The MeHg/Hg ratio (which is assumed to reflect the net production of MeHg normalized to the Hg concentration) varied widely among sites. The highest MeHg/Hg ratios were encountered in loose-fiber sediments situated in southern freshwaters, and the lowest ratios were found in brackish-water sediments and firm, minerogenic sediments at the northernmost freshwater site. This pattern may be explained by an increased MeHg production by methylating bacteria with increasing temperature, availability of energy-rich organic matter (which is correlated with primary production), and availability of neutral Hg sulfides in the sediment pore waters. These factors therefore need to be considered when the risk associated with Hg-contaminated sediments is assessed.
|
|
| 5. |
|
|
| 6. |
- Andersson, Bo, et al.
(författare)
-
Small x phenomenology: summary and status
- 2002
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 25:1, s. 77-101
-
Forskningsöversikt (refereegranskat)abstract
- The aim of this paper is to summarize the general status of our understanding of small-x physics. It is based on presentations and discussions at an informal meeting OIL this topic held in Lund, Sweden, in March 2001. This document also marks the founding of an informal collaboration between experimentalists and theoreticians with a special interest in small-x physics. This paper is dedicated to the memory of Bo Andersson. who died unexpectedly from a heart attack on March 4th, 2002.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Banerjee, Indradumna, et al.
(författare)
-
Slipdisc : A versatile sample preparation platform for point of care diagnostics
- 2017
-
Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 7:56, s. 35048-35054
-
Tidskriftsartikel (refereegranskat)abstract
- We report a microfluidic sample preparation platform called "Slipdisc" based on slipchip technology. Slipdisc is a rotational slipchip that uses a unique hand-wound clockwork mechanism for precise movement of specially fabricated polycarbonate discs. In operation, the microchannels and microchambers carved on the closely aligned microfluidic discs convert from continuous filled paths to defined compartments using the slip movement. The clockwork mechanism introduced here is characterised by a food dye experiment and a conventional HRP TMB reaction before measuring lactate dehydrogenase (LDH) enzyme levels, which is a crucial biomarker for neonatal diagnostics. The colorimetry based detection of LDH was performed with an unmodified camera and an image analysis procedure based on normalising images and observing changes in red channel intensity. The analysis showed a close to unity coefficient of determination (R2 = 0.96) in detecting the LDH concentration when compared with a standard Chemical Analyser, demonstrating the excellent performance of the slipdisc platform with colorimetric detection. The versatile point of care sample preparation platform should ideally be suited for a multitude of applications at resource-limited settings.
|
|
| 10. |
- Bengtsson, Torbjörn, et al.
(författare)
-
The periodontal pathogen Porphyromonas gingivalis cleaves apoB-100 and increases the expression of apoM in LDL in whole blood leading to cell proliferation
- 2008
-
Ingår i: Journal of Internal Medicine. - : Institutionen för medicin och hälsa. - 0954-6820 .- 1365-2796. ; 263:5, s. 558-571
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Several studies support an association between periodontal disease and atherosclerosis with a crucial role for the pathogen Porphyromonas gingivalis. This study aims to investigate the proteolytic and oxidative activity of P. gingivalis on LDL in a whole blood system by using a proteomic approach and analyze the effects of P. gingivalis-modifed LDL on cell proliferation.Methods: The cellular effects of P. gingivalis in human whole blood were assessed using lumi-aggregometry analyzing reactive oxygen species (ROS) production and aggregation. Blood was incubated for 30 min with P. gingivalis, whereafter LDL was isolated and a proteomic approach was applied to examine protein expression. LDL-oxidation was determined by analyzing the formation of protein carbonyls. The effects of P. gingivalis-modifed LDL on fibroblast proliferation were studied using the MTS-assay.Results: Incubation of whole blood with P. gingivalis caused an extensive aggregation and ROS-production, indicating platelet and leukocyte activation. LDL prepared from the bacteria-exposed blood showed an increased protein oxidation, elevated levels of apoM and formation of two apoB-100 N-terminal fragments. P. gingivalis-modified LDL markedly increased the growth of fibroblasts. Inhibition of gingipain R suppressed the modification of LDL by P. gingivalis.Conclusions: The ability of P. gingivalis to change the protein expression and the proliferative capacity of LDL may represent a crucial event in periodontitis-associated atherosclerosis.
|
|
