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| 2. |
- Andersson, Anders, et al.
(författare)
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Effects of Tobacco Smoke on IL-16 in CD8+ Cells from Human Airways and Blood: a Key Role for Oxygen Free Radicals?
- 2011
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Ingår i: AJP - Lung cellular and molecular physiology. - : American Physiological Society. - 1522-1504. ; 300:1
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Tidskriftsartikel (refereegranskat)abstract
- Chronic exposure to tobacco smoke leads to an increase in the frequency of infections and in CD8(+) and CD4(+)cells as well as the CD4(+) chemo-attractant cytokine IL-16 in the airways. Here, we investigated whether tobacco smoke depletes intracellular IL-16 protein and inhibits de novo production of IL-16 in CD8(+) cells from human airways and blood, while at the same time increasing extracellular IL-16 and whether oxygen free radicals (OFR) are involved. Intracellular IL-16 protein in CD8(+) cells and mRNA in all cells was decreased in bronchoalveolar lavage (BAL) samples from chronic smokers. This was also the case in human blood CD8(+) cells exposed to water-soluble tobacco smoke components in vitro; in which oxidized proteins were markedly increased. Extracellular IL-16 protein was increased in cell-free BAL fluid from chronic smokers and in human blood CD8(+) cells exposed to water-soluble tobacco smoke components in vitro. This was not observed in occasional smokers after short-term exposure to tobacco smoke. A marker of activation (CD69) was slightly increased whereas other markers of key cellular functions (membrane integrity, apoptosis and proliferation) in human blood CD8(+) cells in vitro were negatively affected by water-soluble tobacco smoke components. An OFR scavenger prevented these effects whereas a protein synthesis inhibitor, a beta-adrenoceptor, a glucocorticoid receptor agonist, a phosphodiesterase, a calcineurin phosphatase and a caspase-3 inhibitor did not. In conclusion, tobacco smoke depletes preformed intracellular IL-16 protein, inhibits its de novo synthesis and distorts key cellular functions in human CD8(+) cells. OFR may play a key role in this context.
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| 3. |
- Andersson, Bengt, 1947, et al.
(författare)
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Computational fluid dynamics for engineers
- 2011
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- © B. Andersson, R. Andersson, L. Håkansson, M. Mortensen, R. Sudiyo, B. vanWachem, L. Hellstr ¨om 2012. Computational fluid dynamics, CFD, has become an indispensable tool for many engineers. This book gives an introduction to CFD simulations of turbulence, mixing, reaction, combustion and multiphase flows. The emphasis on understanding the physics of these flows helps the engineer to select appropriate models to obtain reliable simulations. Besides presenting the equations involved, the basics and limitations of the models are explained and discussed. The book combined with tutorials, project and power-point lecture notes (all available for download) forms a complete course. The reader is given hands-on experience of drawing, meshing and simulation. The tutorials cover flow and reactions inside a porous catalyst, combustion in turbulent non-premixed flow, and multiphase simulation of evaporation spray respectively. The project deals with design of an industrial-scale selective catalytic reduction process and allows the reader to explore various design improvements and apply best practice guidelines in the CFD simulations.
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| 7. |
- Andersson, Ronnie, 1975, et al.
(författare)
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Enhanced mass and heat transfer in catalytic reactors
- 2013
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Ingår i: Catalysis Today. - : Elsevier BV. - 0920-5861. ; 216, s. 117-120
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Tidskriftsartikel (refereegranskat)abstract
- Mass and heat transfer in square ducts with one side containing a porous wall were simulated using large eddy simulation (LES). Increased wall normal turbulent intensity was observed along the porous wall compared to the smooth wall. Depending on the wall permeability the fluid elements penetrated to different depth resulting in enhanced mass and heat transfer rates. The larges effect was obtained for mass transfer in liquids with up to 20 times larger mass transfer rate, compared to smooth surfaces. An increased penetration into the porous wall was obtained with more open porous structure and with fluids having high density and low viscosity. Most benefit of the porous walls is obtained for fluids with high rho/mu ratio and high Pr or Sc numbers i.e. for mass transfer in liquids.
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| 8. |
- Andersson, Ronnie, 1975, et al.
(författare)
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Modeling the breakup of fluid particles in turbulent flows
- 2006
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Ingår i: AICHE Journal. - 1547-5905 .- 0001-1541. ; 52:6, s. 2031-2038
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Tidskriftsartikel (refereegranskat)abstract
- A model for breakup of fluid particles in turbulent flows is presented in this article. In the new model two criteria, one stress and one energy criteria, are required to be fulfilled for breakup to occur. A new model for interaction frequency between fluid particles and turbulent eddies is also introduced. Analysis of the model reveals that eddies close in size and up to three times larger than the fluid particle contribute most to the overall breakup rate. This explains the experimental findings by the authors and by other researchers presented recently in the literature that fluid particles often deform significantly before breakup occurs. A high-speed imaging technique, 4000 Hz, was used to measure the breakup rate directly without introducing assumptions regarding the daughter size distributions and the number of fragments formed upon breakup. Validation with these measurements shows that the new model gives excellent predictions. © 2006 American Institute of Chemical Engineers.
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| 9. |
- Andersson, Ronnie, 1975, et al.
(författare)
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On the breakup of fluid particles in turbulent flows
- 2006
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Ingår i: AICHE Journal. - 1547-5905 .- 0001-1541. ; 52:6, s. 2020-2030
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Tidskriftsartikel (refereegranskat)abstract
- Dynamics of bubble and drop breakup in turbulent flows have been studied in detail, using a high-speed CCD camera. Analysis of breakup times, deformations, deformation velocities, number of fragments, and the resulting daughter size distributions show that there are several important differences in the breakup mechanism of bubbles and drops. It is shown that the increase in interfacial energy prior to breakup exceeds the increase after breakup. The use of an activation barrier that better describes the turbulent structures that can interact with fluid particles and also cause breakup is proposed. Measurements under identical hydrodynamic conditions reveal that an internal flow redistribution mechanism is responsible for generation of unequal-sized bubble fragments. Due to the three orders of magnitude higher density of liquids than of gases, this mechanism does not occur for drops. The measurements also show that assumption of binary breakup is reasonable for bubbles but not for drops.© 2006 American Institute of Chemical Engineers.
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| 10. |
- Boström, Pontus, 1982, et al.
(författare)
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SNARE proteins mediate fusion between cytosolic lipid droplets and are implicated in insulin sensitivity.
- 2007
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Ingår i: Nature cell biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 9:11, s. 1286-93
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Tidskriftsartikel (refereegranskat)abstract
- The accumulation of cytosolic lipid droplets in muscle and liver cells has been linked to the development of insulin resistance and type 2 diabetes. Such droplets are formed as small structures that increase in size through fusion, a process that is dependent on intact microtubules and the motor protein dynein. Approximately 15% of all droplets are involved in fusion processes at a given time. Here, we show that lipid droplets are associated with proteins involved in fusion processes in the cell: NSF (N-ethylmaleimide-sensitive-factor), alpha-SNAP (soluble NSF attachment protein) and the SNAREs (SNAP receptors), SNAP23 (synaptosomal-associated protein of 23 kDa), syntaxin-5 and VAMP4 (vesicle-associated membrane protein 4). Knockdown of the genes for SNAP23, syntaxin-5 or VAMP4, or microinjection of a dominant-negative mutant of alpha-SNAP, decreases the rate of fusion and the size of the lipid droplets. Thus, the SNARE system seems to have an important role in lipid droplet fusion. We also show that oleic acid treatment decreases the insulin sensitivity of heart muscle cells, and this sensitivity is completely restored by transfection with SNAP23. Thus, SNAP23 might be a link between insulin sensitivity and the inflow of fatty acids to the cell.
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