61. |
- Lundell, H., et al.
(författare)
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Multidimensional diffusion MRI with spectrally modulated gradients reveals unprecedented microstructural detail
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Characterization of porous media is essential in a wide range of biomedical and industrial applications. Microstructural features can be probed non-invasively by diffusion magnetic resonance imaging (dMRI). However, diffusion encoding in conventional dMRI may yield similar signatures for very different microstructures, which represents a significant limitation for disentangling individual microstructural features in heterogeneous materials. To solve this problem, we propose an augmented multidimensional diffusion encoding (MDE) framework, which unlocks a novel encoding dimension to assess time-dependent diffusion specific to structures with different microscopic anisotropies. Our approach relies on spectral analysis of complex but experimentally efficient MDE waveforms. Two independent contrasts to differentiate features such as cell shape and size can be generated directly by signal subtraction from only three types of measurements. Analytical calculations and simulations support our experimental observations. Proof-of-concept experiments were applied on samples with known and distinctly different microstructures. We further demonstrate substantially different contrasts in different tissue types of a post mortem brain. Our simultaneous assessment of restriction size and shape may be instrumental in studies of a wide range of porous materials, enable new insights into the microstructure of biological tissues or be of great value in diagnostics.
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65. |
- Mulder F, Bouakaz L, Lundell A, Venkataramana M, Liljas A, Akke M and Sanyal S
(författare)
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Conformation and dynamics of ribosomal stalk protein L12 in solution and on the ribosome.
- 2004
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Ingår i: Biochemistry. ; 43:23
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Tidskriftsartikel (refereegranskat)abstract
- During translation, the ribosome and several of its constituent proteins undergo structural transitions between different functional states. Protein L12, present in four copies in prokaryotic ribosomes, forms a flexible “stalk” with key function in factor
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66. |
- Oseen-Senda, K. M., et al.
(författare)
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Cooling of PEMFC with pentane boiling in minichannels : A study of flow instabilities using neutron radiography visualization
- 2006
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Ingår i: 16th World Hydrogen Energy Conference 2006. - 9781622765409 ; , s. 2885-2894
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Konferensbidrag (refereegranskat)abstract
- Compared to other heat transfer systems, Polymer Electrolyte Fuel Cells are characterized by very low heat flux. In order to analyse two-phase pentane cooling of bipolar plates, high speed neutron visualizations have been performed in a circular steel tube (Di=1.1 mm, Do=2 mm) at the Institut Laue-Langevin in Grenoble, France. The flow pattern is clearly visible and can be synchronized with time resolved temperature measurements. At low mass flow rates, the pipe wall is high above the saturation temperature and the pipe filled with vapour and liquid slugs. At higher flow rates, the wall is superheated when filled with liquid and at saturation temperature when exposed to a liquid-vapour mixture. An irregular switching between these two states was observed. Superheated liquid exists in both stable and time dependent states. The ?-radiation produced by the neutrons is shown to have an important effect on the boiling process. Simplified steady and time dependent models are proposed to explain the measured wall temperature instabilities and superheat.
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67. |
- Pauwels, A, et al.
(författare)
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How to select patients for antireflux surgery? The ICARUS guidelines (international consensus regarding preoperative examinations and clinical characteristics assessment to select adult patients for antireflux surgery)
- 2019
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Ingår i: Gut. - : BMJ. - 1468-3288 .- 0017-5749. ; 68:11, s. 1928-1941
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Tidskriftsartikel (refereegranskat)abstract
- Antireflux surgery can be proposed in patients with GORD, especially when proton pump inhibitor (PPI) use leads to incomplete symptom improvement. However, to date, international consensus guidelines on the clinical criteria and additional technical examinations used in patient selection for antireflux surgery are lacking. We aimed at generating key recommendations in the selection of patients for antireflux surgery.DesignWe included 35 international experts (gastroenterologists, surgeons and physiologists) in a Delphi process and developed 37 statements that were revised by the Consensus Group, to start the Delphi process. Three voting rounds followed where each statement was presented with the evidence summary. The panel indicated the degree of agreement for the statement. When 80% of the Consensus Group agreed (A+/A) with a statement, this was defined as consensus. All votes were mutually anonymous.ResultsPatients with heartburn with a satisfactory response to PPIs, patients with a hiatal hernia (HH), patients with oesophagitis Los Angeles (LA) grade B or higher and patients with Barrett’s oesophagus are good candidates for antireflux surgery. An endoscopy prior to antireflux surgery is mandatory and a barium swallow should be performed in patients with suspicion of a HH or short oesophagus. Oesophageal manometry is mandatory to rule out major motility disorders. Finally, oesophageal pH (±impedance) monitoring of PPI is mandatory to select patients for antireflux surgery, if endoscopy is negative for unequivocal reflux oesophagitis.ConclusionWith the ICARUS guidelines, we generated key recommendations for selection of patients for antireflux surgery.
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