| 1. |
- Murari, A., et al.
(författare)
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A control oriented strategy of disruption prediction to avoid the configuration collapse of tokamak reactors
- 2024
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Ingår i: Nature Communications. - 2041-1723 .- 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- The objective of thermonuclear fusion consists of producing electricity from the coalescence of light nuclei in high temperature plasmas. The most promising route to fusion envisages the confinement of such plasmas with magnetic fields, whose most studied configuration is the tokamak. Disruptions are catastrophic collapses affecting all tokamak devices and one of the main potential showstoppers on the route to a commercial reactor. In this work we report how, deploying innovative analysis methods on thousands of JET experiments covering the isotopic compositions from hydrogen to full tritium and including the major D-T campaign, the nature of the various forms of collapse is investigated in all phases of the discharges. An original approach to proximity detection has been developed, which allows determining both the probability of and the time interval remaining before an incoming disruption, with adaptive, from scratch, real time compatible techniques. The results indicate that physics based prediction and control tools can be developed, to deploy realistic strategies of disruption avoidance and prevention, meeting the requirements of the next generation of devices.
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| 2. |
- Joffrin, E., et al.
(författare)
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Overview of the JET preparation for deuterium-tritium operation with the ITER like-wall
- 2019
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 59:11
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Forskningsöversikt (refereegranskat)abstract
- For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des. 82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T, leading up to 2020 and the first experiments with 50%/50% D-T mixtures since 1997 and the first ever D-T plasmas with the ITER mix of plasma-facing component materials. For this purpose, a concerted physics and technology programme was launched with a view to prepare the D-T campaign (DTE2). This paper addresses the key elements developed by the JET programme directly contributing to the D-T preparation. This intense preparation includes the review of the physics basis for the D-T operational scenarios, including the fusion power predictions through first principle and integrated modelling, and the impact of isotopes in the operation and physics of D-T plasmas (thermal and particle transport, high confinement mode (H-mode) access, Be and W erosion, fuel recovery, etc). This effort also requires improving several aspects of plasma operation for DTE2, such as real time control schemes, heat load control, disruption avoidance and a mitigation system (including the installation of a new shattered pellet injector), novel ion cyclotron resonance heating schemes (such as the three-ions scheme), new diagnostics (neutron camera and spectrometer, active Alfven eigenmode antennas, neutral gauges, radiation hard imaging systems...) and the calibration of the JET neutron diagnostics at 14 MeV for accurate fusion power measurement. The active preparation of JET for the 2020 D-T campaign provides an incomparable source of information and a basis for the future D-T operation of ITER, and it is also foreseen that a large number of key physics issues will be addressed in support of burning plasmas.
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| 3. |
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| 4. |
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| 5. |
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| 6. |
- Fenstermacher, M.E., et al.
(författare)
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DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
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Tidskriftsartikel (refereegranskat)abstract
- DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.
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| 7. |
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| 8. |
- Labit, B., et al.
(författare)
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Dependence on plasma shape and plasma fueling for small edge-localized mode regimes in TCV and ASDEX Upgrade
- 2019
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 59:8
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Tidskriftsartikel (refereegranskat)abstract
- © 2019 Institute of Physics Publishing. All rights reserved. Within the EUROfusion MST1 work package, a series of experiments has been conducted on AUG and TCV devices to disentangle the role of plasma fueling and plasma shape for the onset of small ELM regimes. On both devices, small ELM regimes with high confinement are achieved if and only if two conditions are fulfilled at the same time. Firstly, the plasma density at the separatrix must be large enough (ne,sep/nG ∼ 0.3), leading to a pressure profile flattening at the separatrix, which stabilizes type-I ELMs. Secondly, the magnetic configuration has to be close to a double null (DN), leading to a reduction of the magnetic shear in the extreme vicinity of the separatrix. As a consequence, its stabilizing effect on ballooning modes is weakened.
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| 9. |
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| 10. |
- Stroth, U., et al.
(författare)
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Progress from ASDEX Upgrade experiments in preparing the physics basis of ITER operation and DEMO scenario development
- 2022
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 62:4
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Tidskriftsartikel (refereegranskat)abstract
- An overview of recent results obtained at the tokamak ASDEX Upgrade (AUG) is given. A work flow for predictive profile modelling of AUG discharges was established which is able to reproduce experimental H-mode plasma profiles based on engineering parameters only. In the plasma center, theoretical predictions on plasma current redistribution by a dynamo effect were confirmed experimentally. For core transport, the stabilizing effect of fast ion distributions on turbulent transport is shown to be important to explain the core isotope effect and improves the description of hollow low-Z impurity profiles. The L-H power threshold of hydrogen plasmas is not affected by small helium admixtures and it increases continuously from the deuterium to the hydrogen level when the hydrogen concentration is raised from 0 to 100%. One focus of recent campaigns was the search for a fusion relevant integrated plasma scenario without large edge localised modes (ELMs). Results from six different ELM-free confinement regimes are compared with respect to reactor relevance: ELM suppression by magnetic perturbation coils could be attributed to toroidally asymmetric turbulent fluctuations in the vicinity of the separatrix. Stable improved confinement mode plasma phases with a detached inner divertor were obtained using a feedback control of the plasma β. The enhanced D α H-mode regime was extended to higher heating power by feedback controlled radiative cooling with argon. The quasi-coherent exhaust regime was developed into an integrated scenario at high heating power and energy confinement, with a detached divertor and without large ELMs. Small ELMs close to the separatrix lead to peeling-ballooning stability and quasi continuous power exhaust. Helium beam density fluctuation measurements confirm that transport close to the separatrix is important to achieve the different ELM-free regimes. Based on separatrix plasma parameters and interchange-drift-Alfvén turbulence, an analytic model was derived that reproduces the experimentally found important operational boundaries of the density limit and between L- and H-mode confinement. Feedback control for the X-point radiator (XPR) position was established as an important element for divertor detachment control. Stable and detached ELM-free phases with H-mode confinement quality were obtained when the XPR was moved 10 cm above the X-point. Investigations of the plasma in the future flexible snow-flake divertor of AUG by means of first SOLPS-ITER simulations with drifts activated predict beneficial detachment properties and the activation of an additional strike point by the drifts.
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| 11. |
- Reimerdes, H., et al.
(författare)
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Overview of the TCV tokamak experimental programme
- 2022
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 62:4
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Tidskriftsartikel (refereegranskat)abstract
- The tokamak a configuration variable (TCV) continues to leverage its unique shaping capabilities, flexible heating systems and modern control system to address critical issues in preparation for ITER and a fusion power plant. For the 2019-20 campaign its configurational flexibility has been enhanced with the installation of removable divertor gas baffles, its diagnostic capabilities with an extensive set of upgrades and its heating systems with new dual frequency gyrotrons. The gas baffles reduce coupling between the divertor and the main chamber and allow for detailed investigations on the role of fuelling in general and, together with upgraded boundary diagnostics, test divertor and edge models in particular. The increased heating capabilities broaden the operational regime to include T (e)/T (i) similar to 1 and have stimulated refocussing studies from L-mode to H-mode across a range of research topics. ITER baseline parameters were reached in type-I ELMy H-modes and alternative regimes with 'small' (or no) ELMs explored. Most prominently, negative triangularity was investigated in detail and confirmed as an attractive scenario with H-mode level core confinement but an L-mode edge. Emphasis was also placed on control, where an increased number of observers, actuators and control solutions became available and are now integrated into a generic control framework as will be needed in future devices. The quantity and quality of results of the 2019-20 TCV campaign are a testament to its successful integration within the European research effort alongside a vibrant domestic programme and international collaborations.
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| 12. |
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| 13. |
- Coda, S., et al.
(författare)
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Physics research on the TCV tokamak facility: From conventional to alternative scenarios and beyond
- 2019
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 59:11
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Tidskriftsartikel (refereegranskat)abstract
- The research program of the TCV tokamak ranges from conventional to advanced-tokamak scenarios and alternative divertor configurations, to exploratory plasmas driven by theoretical insight, exploiting the device's unique shaping capabilities. Disruption avoidance by real-time locked mode prevention or unlocking with electron-cyclotron resonance heating (ECRH) was thoroughly documented, using magnetic and radiation triggers. Runaway generation with high-Z noble-gas injection and runaway dissipation by subsequent Ne or Ar injection were studied for model validation. The new 1 MW neutral beam injector has expanded the parameter range, now encompassing ELMy H-modes in an ITER-like shape and nearly non-inductive H-mode discharges sustained by electron cyclotron and neutral beam current drive. In the H-mode, the pedestal pressure increases modestly with nitrogen seeding while fueling moves the density pedestal outwards, but the plasma stored energy is largely uncorrelated to either seeding or fueling. High fueling at high triangularity is key to accessing the attractive small edge-localized mode (type-II) regime. Turbulence is reduced in the core at negative triangularity, consistent with increased confinement and in accord with global gyrokinetic simulations. The geodesic acoustic mode, possibly coupled with avalanche events, has been linked with particle flow to the wall in diverted plasmas. Detachment, scrape-off layer transport, and turbulence were studied in L- and H-modes in both standard and alternative configurations (snowflake, super-X, and beyond). The detachment process is caused by power 'starvation' reducing the ionization source, with volume recombination playing only a minor role. Partial detachment in the H-mode is obtained with impurity seeding and has shown little dependence on flux expansion in standard single-null geometry. In the attached L-mode phase, increasing the outer connection length reduces the in-out heat-flow asymmetry. A doublet plasma, featuring an internal X-point, was achieved successfully, and a transport barrier was observed in the mantle just outside the internal separatrix. In the near future variable-configuration baffles and possibly divertor pumping will be introduced to investigate the effect of divertor closure on exhaust and performance, and 3.5 MW ECRH and 1 MW neutral beam injection heating will be added.
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| 14. |
- Mantsinen, M. J., et al.
(författare)
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Experiments in high-performance JET plasmas in preparation of second harmonic ICRF heating of tritium in ITER
- 2023
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Ingår i: Nuclear Fusion. - : Institute of Physics (IOP). - 0029-5515 .- 1741-4326. ; 63:11
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Tidskriftsartikel (refereegranskat)abstract
- The reference ion cyclotron resonance frequency (ICRF) heating schemes for ITER deuterium-tritium (D-T) plasmas at the full magnetic field of 5.3 T are second harmonic heating of T and 3He minority heating. The wave-particle resonance location for these schemes coincide and are central at a wave frequency of 53 MHz at 5.3 T. Experiments have been carried out in the second major D-T campaign (DTE2) at JET, and in its prior D campaigns, to integrate these ICRF scenarios in JET high-performance plasmas and to compare their performance with the commonly used hydrogen (H) minority heating. In 50:50 D:T plasmas, up to 35% and 5% larger fusion power and diamagnetic energy content, respectively, were obtained with second harmonic heating of T as compared to H minority heating at comparable total input powers and gas injection rates. The core ion temperature was up to 30% and 20% higher with second harmonic T and 3He minority heating, respectively, with respect to H minority heating. These are favourable results for the use of these scenarios in ITER and future fusion reactors. According to modelling, adding ICRF heating to neutral beam injection using D and T beams resulted in a 10%-20% increase of on-axis bulk ion heating in the D-T plasmas due to its localisation in the plasma core. Central power deposition was confirmed with the break-in-slope and fast Fourier transform analysis of ion and electron temperature in response to ICRF modulation. The tail temperature of fast ICRF-accelerated tritons, their enhancement of the fusion yield and time behaviour as measured by an upgraded magnetic proton recoil spectrometer and neutral particle analyser were found in agreement with theoretical predictions. No losses of ICRF-accelerated ions were observed by fast ion detectors, which was as expected given the high plasma density of n e approximate to 7-8 x 1019 m-3 in the main heating phase that limited the formation of ICRF-accelerated fast ion tails. 3He was introduced in the machine by 3He gas injection, and the 3He concentration was measured by a high-resolution optical penning gauge in the sub-divertor region. The DTE2 experiments with 3He minority heating were carried with a low 3He concentration in the range of 2%-4% given the fact that the highest neutron rates with 3He minority heating in D plasmas were obtained at low 3He concentrations of similar to 2%, which also coincided with the highest plasma diamagnetic energy content. In addition to 3He introduced by 3He gas injection, an intrinsic concentration of 3He of the order of 0.2%-0.4% was measured in D-T plasmas before 3He was introduced in the device, which is attributed to the radioactive decay of tritium to 3He. According to modelling, even such low intrinsic concentrations of 3He lead to significant changes in ICRF power partitioning during second harmonic heating of T due to absorption of up to 30% of the wave power by 3He.
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| 15. |
- Chellaï, O., et al.
(författare)
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Millimeter-wave beam scattering and induced broadening by plasma turbulence in the TCV tokamak
- 2021
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 61:6
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Tidskriftsartikel (refereegranskat)abstract
- The scattering of millimeter-wave beams from electron density fluctuations and the associated beam broadening are experimentally demonstrated. Using a dedicated setup, instantaneous deflection and (de-)focusing of the beam due to density blobs on the beam path are shown to agree with full-wave simulations. The detected time-averaged wave power transmitted through the turbulent plasma is reproduced by the radiative-transfer model implemented in the WKBeam code, which predicts a ∼50% turbulence-induced broadening of the beam cross-section. The role of core turbulence for the considered geometry is highlighted.
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| 16. |
- Maslov, M., et al.
(författare)
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JET D-T scenario with optimized non-thermal fusion
- 2023
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Ingår i: Nuclear Fusion. - : Institute of Physics (IOP). - 0029-5515 .- 1741-4326. ; 63:11
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Tidskriftsartikel (refereegranskat)abstract
- In JET deuterium-tritium (D-T) plasmas, the fusion power is produced through thermonuclear reactions and reactions between thermal ions and fast particles generated by neutral beam injection (NBI) heating or accelerated by electromagnetic wave heating in the ion cyclotron range of frequencies (ICRFs). To complement the experiments with 50/50 D/T mixtures maximizing thermonuclear reactivity, a scenario with dominant non-thermal reactivity has been developed and successfully demonstrated during the second JET deuterium-tritium campaign DTE2, as it was predicted to generate the highest fusion power in JET with a Be/W wall. It was performed in a 15/85 D/T mixture with pure D-NBI heating combined with ICRF heating at the fundamental deuterium resonance. In steady plasma conditions, a record 59 MJ of fusion energy has been achieved in a single pulse, of which 50.5 MJ were produced in a 5 s time window (P fus = 10.1 MW) with average Q = 0.33, confirming predictive modelling in preparation of the experiment. The highest fusion power in these experiments, P fus = 12.5 MW with average Q = 0.38, was achieved over a shorter 2 s time window, with the period of sustainment limited by high-Z impurity accumulation. This scenario provides unique data for the validation of physics-based models used to predict D-T fusion power.
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| 17. |
- Mantica, P., et al.
(författare)
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Detection of alpha heating in JET-ILW DT plasmas by a study of the electron temperature response to ICRH modulation
- 2024
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Ingår i: Nuclear Fusion. - Culham Sci Ctr, JET, EUROfus Consortium, Abingdon OX14 3DB, England. [Mantica, P.; Casiraghi, I.; Dal Molin, A.; Rigamonti, D.; Tardocchi, M.] CNR, Inst Plasma Sci & Technol, Milan, Italy. [Auriemma, F.] Consorzio RFX ISTP CNR, Padua, Italy. [Gallart, D.; Mantsinen, M.] Barcelona Supercomp Ctr, Barcelona, Spain. [Kirov, K.; Jacquet, P.; Kiptily, V.; Litherland-Smith, E.; Maggi, C. F.; Maslov, M.; Menmuir, S.; Stancar, Z.; Sun, H.; Szepesi, G.] Culham Sci Ctr, UKAEA, Abingdon, England. [Lerche, E.; Van Eester, D.] ERM KMS, Lab Plasma Phys, Brussels, Belgium. [Salmi, A.] VTT, POB 1000, FI-02044 Espoo, Finland. [Delabie, E.] Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. [Eriksson, J.] Uppsala Univ, Dept Phys & Astron, Uppsala, Sweden. [Garcia, J.; Huynh, P.] CEA, IRFM, St Paul Les Durance, France. [$$$Jonsson, T.] KTH, Fus Plasma Phys, EES, Stockholm, Sweden. [Mantsinen, M.] ICREA, Barcelona, Spain. [Marcer, G.; Nocente, M.] Univ Milano Bicocca, Milan, Italy. [Peluso, E.] Univ Roma Tor Vergata, Rome, Italy. [Peluso, E.; Pucella, G.] ENEA CR Frascati, Frascati, Italy. : IOP Publishing. - 0029-5515 .- 1741-4326. ; 64:8
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Tidskriftsartikel (refereegranskat)abstract
- In the JET DTE2 campaign a new method was successfully tested to detect the heating of bulk electrons by alpha-particles, using the dynamic response of the electron temperature T e to the modulation of ion cyclotron resonance heating (ICRH). A fundamental deuterium (D) ICRH scheme was applied to a tritium-rich hybrid plasma with D-neutral beam injection (NBI). The modulation of the ion temperature T i and of the ICRH accelerated deuterons leads to modulated alpha-heating with a large delay with respect to other modulated electron heating terms. A significant phase delay of similar to 40 degrees is measured between central T e and T i, which can only be explained by alpha-particle heating. Integrated modelling using different models for ICRH absorption and ICRH/NBI interaction reproduces the effect qualitatively. Best agreement with experiment is obtained with the European Transport Solver/Heating and Current Drive workflow.
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| 18. |
- Nocente, M., et al.
(författare)
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Fusion product measurements by nuclear diagnostics in the Joint European Torus deuterium-tritium 2 campaign (invited)
- 2022
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Ingår i: Review of Scientific Instruments. - : American Institute of Physics (AIP). - 0034-6748 .- 1089-7623. ; 93:9
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Tidskriftsartikel (refereegranskat)abstract
- A new deuterium-tritium experimental, DTE2, campaign has been conducted at the Joint European Torus (JET) between August 2021 and late December 2021. Motivated by significant enhancements in the past decade at JET, such as the ITER-like wall and enhanced auxiliary heating power, the campaign achieved a new fusion energy world record and performed a broad range of fundamental experiments to inform ITER physics scenarios and operations. New capabilities in the area of fusion product measurements by nuclear diagnostics were available as a result of a decade long enhancement program. These have been tested for the first time in DTE2 and a concise overview is provided here. Confined alpha particle measurements by gamma-ray spectroscopy were successfully demonstrated, albeit with limitations at neutron rates higher than some 10(17) n/s. High resolution neutron spectroscopy measurements with the magnetic proton recoil instrument were complemented by novel data from a set of synthetic diamond detectors, which enabled studies of the supra-thermal contributions to the neutron emission. In the area of escaping fast ion diagnostics, a lost fast ion detector and a set of Faraday cups made it possible to determine information on the velocity space and poloidal distribution of the lost alpha particles for the first time. This extensive set of data provides unique information for fundamental physics studies and validation of the numerical models, which are key to inform the physics and scenarios of ITER. Published under an exclusive license by AIP Publishing.
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| 19. |
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| 20. |
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| 21. |
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| 22. |
- Nocente, M., et al.
(författare)
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Generation and observation of fast deuterium ions and fusion-born alpha particles in JET D-He-3 plasmas with the 3-ion radio-frequency heating scenario
- 2020
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Ingår i: Nuclear Fusion. - : IOP PUBLISHING LTD. - 0029-5515 .- 1741-4326. ; 60:12
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Tidskriftsartikel (refereegranskat)abstract
- Dedicated experiments to generate energetic D ions and D-(3) He fusion-born alpha particles were performed at the Joint European Torus (JET) with the ITER-like wall (ILW). Using the 3-ion D-(D-NBI)-(3) He radio frequency (RF) heating scenario, deuterium ions from neutral beam injection (NBI) were accelerated in the core of mixed D-(3) He plasmas to higher energies with ion cyclotron resonance frequency (ICRF) waves, in turn leading to a core-localized source of alpha particles. The fast-ion distribution of RF-accelerated D-NBI ions was controlled by varying the ICRF and NBI power (P-ICRF approximate to 4-6 MW, P-NBI approximate to 3-20 MW), resulting in rather high D-D neutron (approximate to 1x10(16) s(-1)) and D-(3) He alpha rates (approximate to 2x10(16) s(-1)) at moderate input heating power. Theory and TRANSP analysis shows that large populations of co-passing MeV-range D ions were generated using the D-(D-NBI)-(3) He 3-ion ICRF scenario. This important result is corroborated by several experimental observations, in particular gamma-ray measurements. The developed experimental scenario at JET provides unique conditions for probing several aspects of future burning plasmas, such as the contribution from MeV range ions to global confinement, but without introducing tritium. Dominant fast-ion core electron heating with T-i approximate to T-e and a rich variety of fast-ion driven Alfven eigenmodes (AEs) were observed in these D-(3) He plasmas. The observed AE activities do not have a detrimental effect on the thermal confinement and, in some cases, may be driven by the fusion born alpha particles. A strong continuous increase in neutron rate was observed during long-period sawteeth (>1 s), accompanied by the observation of reversed shear AEs, which implies that a non monotonic q profile was systematically developed in these plasmas, sustained by the large fast-ion populations generated by the 3-ion ICRF scenario.
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| 23. |
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| 26. |
- Campos, Alexandre B., et al.
(författare)
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Adaptive Target Enhancer : Bridging the Gap between Synthetic and Measured SAR Images for Automatic Target Recognition
- 2023
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Ingår i: Proceedings of the IEEE Radar Conference. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781665436694
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Konferensbidrag (refereegranskat)abstract
- Automatic target recognition (ATR) algorithms have been successfully used for vehicle classification in synthetic aperture radar (SAR) images over the past few decades. For this application, however, the scarcity of labeled data is often a limiting factor for supervised approaches. While the advent of computer-simulated images may result in additional data for ATR, there is still a substantial gap between synthetic and measured images. In this paper, we propose the so-called adaptive target enhancer (ATE), a tool designed to automatically delimit and weight the region of an image that contains or is affected by the presence of a target. Results for the publicly released Synthetic and Measured Paired and Labeled Experiment (SAMPLE) dataset show that, by defining regions of interest and suppressing the background, we can increase the classification accuracy from 68% to 84% while only using artificially generated images for training. © 2023 IEEE.
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| 27. |
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| 28. |
- Chen, Robert, et al.
(författare)
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Phase II Study of the Efficacy and Safety of Pembrolizumab for Relapsed/Refractory Classic Hodgkin Lymphoma
- 2017
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Ingår i: Journal of Clinical Oncology. - 0732-183X .- 1527-7755. ; 35:19, s. 2125-2132
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Hodgkin Reed-Sternberg cells harbor alterations in chromosome 9p24.1, leading to overexpression of programmed death-ligand 1 (PD-L1) and PD-L2. Pembrolizumab, a programmed death 1-blocking antibody, demonstrated a high overall response rate (ORR) in patients with relapsed or refractory classic Hodgkin lymphoma (rrHL) in phase I testing. Methods KEYNOTE-087 (ClinicalTrials.gov identifier, NCT02453594) was a single-arm phase II study of pembrolizumab in three cohorts of patients with rrHL, defined on the basis of lymphoma progression after (1) autologous stem cell transplantation (ASCT) and subsequent brentuximab vedotin (BV); (2) salvage chemotherapy and BV, and thus, ineligible for ASCT because of chemoresistant disease; and (3) ASCT, but without BV after transplantation. Patients received pembrolizumab 200 mg once every 3 weeks. Response was assessed every 12 weeks. The primary end points were ORR by central review and safety. Results A total of 210 patients were enrolled and treated (69 in cohort 1, 81 in cohort 2, and 60 in cohort 3). At the time of analysis, patients received a median of 13 treatment cycles. Per central review, the ORR was 69.0% (95% CI, 62.3% to 75.2%), and the complete response rate was 22.4% (95% CI, 16.9% to 28.6%). By cohort, ORRs were 73.9% for cohort 1, 64.2% for cohort 2, and 70.0% for cohort 3. Thirty-one patients had a response >= 6 months. The safety profile was largely consistent with previous pembrolizumab studies. Conclusion Pembrolizumab was associated with high response rates and an acceptable safety profile in patients with rrHL, offering a new treatment paradigm for this disease.
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| 29. |
- Duodu, Samuel, et al.
(författare)
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Bartonella Infections in Deer Keds (Lipoptena cervi) and Moose (Alces alces) in Norway
- 2013
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 79:1, s. 322-327
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Tidskriftsartikel (refereegranskat)abstract
- Infections with Bartonella spp. have been recognized as emerging zoonotic diseases in humans. Large knowledge gaps exist, however, relating to reservoirs, vectors, and transmission of these bacteria. We describe identification by culture, PCR, and housekeeping gene sequencing of Bartonella spp. in fed, wingless deer keds (Lipoptena cervi), deer ked pupae, and blood samples collected from moose, Alces alces, sampled within the deer ked distribution range in Norway. Direct sequencing from moose blood sampled in a deer ked-free area also indicated Bartonella infection but at a much lower prevalence. The sequencing data suggested the presence of mixed infections involving two species of Bartonella within the deer ked range, while moose outside the range appeared to be infected with a single species. Bartonella were not detected or cultured from unfed winged deer keds. The results may indicate that long-term bacteremia in the moose represents a reservoir of infection and that L. cervi acts as a vector for the spread of infection of Bartonella spp. Further research is needed to evaluate the role of L. cervi in the transmission of Bartonella to animals and humans and the possible pathogenicity of these bacteria for humans and animals.
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| 30. |
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| 33. |
- Hernandez, Jorge, et al.
(författare)
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Human-Associated Extended-Spectrum beta-Lactamase in the Antarctic
- 2012
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Ingår i: Applied and Environmental Microbiology. - Washington, DC, United States : American Society for Microbiology. - 0099-2240 .- 1098-5336. ; 78:6, s. 2056-2058
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Tidskriftsartikel (refereegranskat)abstract
- Escherichia coli bacteria with extended-spectrum beta-lactamase (ESBL) type CTX-M resistance were isolated from water samples collected close to research stations in Antarctica. The isolates had bla(CTX-M-1) and bla(CTX-M-15) genotypes and sequence types (ST) indicative of a human-associated origin. This is the first record of ESBL-producing enterobacteria from Antarctica.
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| 34. |
- Koszelow, D., et al.
(författare)
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Pre-oxidation of porous ferritic Fe22Cr alloys for lifespan extension at high-temperature
- 2024
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Ingår i: Corrosion Science. - 0010-938X. ; 234
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Tidskriftsartikel (refereegranskat)abstract
- Pre-oxidation of porous ferritic Fe22Cr alloys was extensively studied in this paper. Weight gain measurements and SEM analysis revealed that pre-oxidation performed at 900°C for 40 min increased the lifespan of the alloy. A Cr evaporation study did not disclose any significant influence of the pre-oxidation process on the Cr content in the alloy. For a more detailed assessment, TEM imaging and X-ray tomography measurements of pre-oxidized samples were performed. These analyses showed that alteration in the grain and grain boundary diffusion fluxes might be the key for explaining the corrosion prevention role of pre-oxidation.
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| 35. |
- Lindskog, Anders, et al.
(författare)
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Oxygenation of the Baltoscandian shelf linked to Ordovician biodiversification
- 2023
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Ingår i: Nature Geoscience. - 1752-0894. ; 16:11, s. 1047-1053
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Tidskriftsartikel (refereegranskat)abstract
- Marine biodiversity increased markedly during the Ordovician Period (~487–443 million years ago). Some intervals within the Ordovician were associated with unusually rapid and prominent rises in taxonomic richness, the reasons for which remain debated. Links between increased oxygenation and biodiversification have been proposed, although supporting marine oxygen proxy data are limited. Here we present an expansive multi-site iodine-to-calcium (I/Ca) record from Lower–Middle Ordovician marine carbonates in Baltoscandia that provides a detailed account of the spatio-temporal development of oxygen conditions across this palaeoshelf. The data document progressive oxygenation of regional seafloor environments, with well-oxygenated waters sourced from the palaeoequatorward Iapetus Ocean and peak I/Ca values (that is, dissolved oxygen concentrations) coinciding with the most pronounced biodiversity increases and ecosystem reorganizations during this time interval. This occurred while the climate cooled, global sea level dropped and carbonate deposits became regionally dominant. The results suggest that ventilation of shelves played a critical role in regulating early Palaeozoic marine biodiversity via development of ecospace and aerobic–metabolic conditions.
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| 36. |
- Mamduhi, M. H., et al.
(författare)
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Error-dependent data scheduling in resource-aware multi-loop networked control systems
- 2017
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Ingår i: Automatica. - : Elsevier Ltd. - 0005-1098 .- 1873-2836. ; 81, s. 209-216
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we address the problem of event-based data scheduling for multiple heterogeneous LTI control loops over a shared resource-constrained communication network. We introduce a novel bi-character scheduling scheme, which dynamically prioritizes the channel access at each time-step according to an error-dependent priority measure. Given local error thresholds for each control loop, the scheduling policy deterministically blocks the transmission from sub-systems with lower error values. The scheduler then allocates the limited communication resource probabilistically among the eligible sub-systems based on a prioritized measure. We prove stochastic stability of the networked control system under the proposed scheduler in terms of f-ergodicity of the overall network-induced error. Uniform analytical performance bounds are further derived for an average cost function comprised of a quadratic error term and transmission penalty. The simulation results show that our approach results in a significant reduction of the aggregate network-induced error variance compared to the conventional scheduling protocols.
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| 37. |
- Matthiasson, S E, et al.
(författare)
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Study of the interaction of dextran and enoxaparin on haemostasis in humans
- 1994
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Ingår i: Thrombosis and Haemostasis. - 0340-6245. ; 72:5, s. 722-727
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Tidskriftsartikel (refereegranskat)abstract
- The effect on haemostatic variables by dextran 70, enoxaparin and their combinations, given in doses of 500 ml i.v. and 40 mg s.c. respectively, was studied in a randomised cross-over fashion in twelve healthy male volunteers. Antifactor-IIa activity, antifactor-Xa activity, APTT, factor VIII, vWF, bleeding time and blood counts were analysed over a 24-h period. Dextran alone did not affect antifactor-IIa activity and antifactor-Xa activity. No difference in antifactor-IIa and antifactor-Xa activity was found for Amax, tmax, AUC0-8 h and AUC0-24 h in the groups treated with enoxaparin or the combination of enoxaparin and dextran. Only minor changes in APTT were observed without statistical significance between the treatment groups. Factor VIII did not change significantly in the three treatment groups. However, vWF was significantly reduced in the dextran and the dextran/enoxaparin group (p = 0.046 and 0.01 respectively) but no difference was found between the two groups. Bleeding time was not significantly increased four hours after administration of the test substances and no difference was found between the individual treatment groups. Our findings indicate that dextran can be combined with enoxaparin, when used in thromboprophylactic doses, without increased risk for bleeding.
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| 38. |
- Molin, Anna-Maja, et al.
(författare)
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A novel microdeletion syndrome at 3q13.31 characterised by developmental delay, postnatal overgrowth, hypoplastic male genitals, and characteristic facial features
- 2012
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Ingår i: Journal of Medical Genetics. - : BMJ. - 0022-2593 .- 1468-6244. ; 49:2, s. 104-109
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Tidskriftsartikel (refereegranskat)abstract
- Background Congenital deletions affecting 3q11q23 have rarely been reported and only five cases have been molecularly characterised. Genotype. phenotype correlation has been hampered by the variable sizes and breakpoints of the deletions. In this study, 14 novel patients with deletions in 3q11q23 were investigated and compared with 13 previously reported patients. Methods Clinical data were collected from 14 novel patients that had been investigated by high resolution microarray techniques. Molecular investigation and updated clinical information of one cytogenetically previously reported patient were also included. Results The molecular investigation identified deletions in the region 3q12.3q21.3 with different boundaries and variable sizes. The smallest studied deletion was 580 kb, located in 3q13.31. Genotype. phenotype comparison in 24 patients sharing this shortest region of overlapping deletion revealed several common major characteristics including significant developmental delay, muscular hypotonia, a high arched palate, and recognisable facial features including a short philtrum and protruding lips. Abnormal genitalia were found in the majority of males, several having micropenis. Finally, a postnatal growth pattern above the mean was apparent. The 580 kb deleted region includes five RefSeq genes and two of them are strong candidate genes for the developmental delay: DRD3 and ZBTB20. Conclusion A newly recognised 3q13.31 microdeletion syndrome is delineated which is of diagnostic and prognostic value. Furthermore, two genes are suggested to be responsible for the main phenotype.
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| 39. |
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| 40. |
- Molin, D., et al.
(författare)
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Early and intermediate stage Hodgkin's lymphoma - Report from the Swedish National Care Programme
- 2003
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Ingår i: European Journal of Haematology. - : Wiley. - 0902-4441 .- 1600-0609. ; 70, s. 172-
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Tidskriftsartikel (refereegranskat)abstract
- In Sweden a National Care Programme provides treatment principles for Hodgkin's lymphoma (HL) since 1985, for early and intermediate stages often less extensive than international recommendations. The purpose is to evaluate long-term results of these principles. A total of 308 patients (167 men and 141 women), 17-59 yr old (median 31), diagnosed during 1985-92, pathological stage (PS) I-III1A and I-IIB and clinical stage (CS) I-IIA, mean follow-up 8.8 yr, were studied. Staging laparotomy was recommended in CS IIA. Recommended treatment was mantle or mini-mantle radiotherapy (RT) alone in CS IA, and PS I-IIA and subtotal nodal irradiation in PS III1A if the disease was not bulky. Patients in PS I-IIA and III1A with bulky disease, and PS I-IIB received one cycle of mechlorethamine, vincristine, prednisone, procarbazine/doxorubicin, bleomycin, vinblastine, lacarbazine (MOPP/ABVD) before irradiation. The remaining patients received three to four cycles of MOPP/ABVD with RT to bulky disease. Relapse-free (RFS), Hodgkin specific (HLS), and overall survival (OS) at 10 yr were 74%, 92% and 85%. In the individual stages, RFS ranged from 53% (PSIII1A) to 90% (PS IA). RFS (P = 0.006), HLS, and OS were significantly better in patients treated with chemotherapy compared with those treated with RT alone, especially in patients with bulky disease (P = 0.0005). The international prognostic score did not provide any prognostic information. The OS rates are in agreement with results from international centres during that time. The recommended treatment was sufficient to produce the desired results of <20-30% recurrences, except in PS III1A. Most relapses could be salvaged. Patients with risk factors treated with one MOPP/ABVD and RT had an excellent outcome, superior to those without risk factors treated with RT alone. These results favour the trend to treat early and intermediate stages with a short course of chemotherapy followed by limited RT.
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| 41. |
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| 42. |
- Molin, Ricardo D., Jr., et al.
(författare)
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A CHANGE DETECTION ALGORITHM FOR SAR IMAGES BASED ON LOGISTIC REGRESSION
- 2019
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Ingår i: 2019 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS 2019). - : IEEE. - 9781538691540 ; , s. 1514-1517
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Konferensbidrag (refereegranskat)abstract
- This paper presents an incoherent change detection algorithm (CDA) for synthetic aperture radar (SAR) images based on logistic regression. The input data consists of a set of 24 SAR images acquired in a test site in northern Sweden [1]. Subsets of these images are trained based on pixel amplitude, flight heading and neighboring features such as local mean, standard deviation and skewness. The proposed method intends to explore the advantadges from both pixel- and object-based approaches, while evaluating multiple features in amplitude only SAR images. Preliminary results based on K-fold cross validation have shown that the proposed CDA achieves good performance when compared to the results presented in [1].
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| 43. |
- O'Reilly, Éilis J, et al.
(författare)
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Prediagnostic body size and risk of amyotrophic lateral sclerosis death in 10 studies
- 2018
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Ingår i: Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration. - : Informa UK Limited. - 2167-8421 .- 2167-9223. ; 19:5-6, s. 396-406
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES AND METHODS: Using pooled multivariable-adjusted rate ratios (RR), we explored relationships between prediagnostic body-mass-index (BMI), waist-to-hip-ratio (WHR), and weight-gain during adulthood, and ALS in 419,894 women and 148,166 men from 10 community-based cohorts in USA, Europe, and Australia; 428 ALS deaths were documented in women and 204 in men.RESULTS: , limiting power. Weight-gain during adulthood was strongly associated with lower ALS; for an additional 1kg gain in weight/year, the RR = 0.43 (95% CI: 0.28-0.65; p < 0.001). Associations persisted when adjusted for diabetes at enrollment, restricted to never-smokers, and ALS deaths in the 5 years after enrollment were excluded (accounting for recent weight loss).CONCLUSIONS: These findings confirm somewhat conflicting, underpowered evidence that adiposity is inversely associated with ALS. We newly demonstrate that weight-gain during adulthood is strongly predictive of lower ALS risk.
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| 44. |
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| 45. |
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| 46. |
- Panontin, E., et al.
(författare)
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Comparison of unfolding methods for the inference of runaway electron energy distribution from gamma-ray spectroscopic measurements
- 2021
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Ingår i: Journal of Instrumentation. - : Institute of Physics Publishing (IOPP). - 1748-0221. ; 16:12
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Tidskriftsartikel (refereegranskat)abstract
- Unfolding techniques are employed to reconstruct the 1D energy distribution of runaway electrons from Bremsstrahlung hard X-ray spectrum emitted during plasma disruptions in tokamaks. Here we compare four inversion methods: truncated singular value decomposition, which is a linear algebra technique, maximum likelihood expectation maximization, which is an iterative method, and Tikhonov regularization applied to chi(2) and Poisson statistics, which are two minimization approaches. The reconstruction fidelity and the capability of estimating cumulative statistics, such as the mean and maximum energy, have been assessed on both synthetic and experimental spectra. The effect of measurements limitations, such as the low energy cut and few number of counts, on the final reconstruction has also been studied. We find that the iterative method performs best as it better describes the statistics of the experimental data and is more robust to noise in the recorded spectrum.
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| 47. |
- Pedersen, Mette A., et al.
(författare)
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Focal skeletal FDG uptake indicates poor prognosis in cHL regardless of extent and first-line chemotherapy
- 2019
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Ingår i: British Journal of Haematology. - : WILEY. - 0007-1048 .- 1365-2141. ; 186:3, s. 431-439
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Tidskriftsartikel (refereegranskat)abstract
- F-18-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) is used for staging classical Hodgkin lymphoma (cHL) with high sensitivity for skeletal involvement. However, it is unclear whether a single bone lesion carries the same adverse prognosis as multifocal lesions and if this is affected by type of chemotherapy [ABVD (adriamycin, bleomycin, vincristine, dacarbazine) versus BEACOPP (bleomycin, etoposide, adriamycin, cyclophosphamide, vincristine, procarbazine, prednisone)]. We reviewed the clinico-pathological and outcome data from 209 patients with newly diagnosed cHL staged by FDG-PET/CT. Patterns of skeletal/bone marrow uptake (BMU) were divided into 'low' and 'high' diffuse BMU (i.e. without focal lesions), and unifocal or multifocal lesions. Additional separate survival analysis was performed, taking type of chemotherapy into account. Forty patients (19 center dot 2%) had skeletal lesions (20 unifocal, 20 multifocal). The 3-year progression-free-survival (PFS) was 80% for patients with 'low BMU', 87% for 'high BMU', 69% for 'unifocal' and 51% for 'multifocal' lesions; median follow-up was 38 months. The presence of bone lesions, both uni- and multifocal, was associated with significantly inferior PFS (log rank P = 0 center dot 0001), independent of chemotherapy type. Thus, increased diffuse BMU should not be considered as a risk factor in cHL, whereas unifocal or multifocal bone lesions should be regarded as important predictors of adverse outcome, irrespective of the chemotherapy regimen used.
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| 48. |
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| 49. |
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| 50. |
- Rigamonti, D., et al.
(författare)
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The single crystal diamond-based diagnostic suite of the JET tokamak for 14 MeV neutron counting and spectroscopy measurements in DT plasmas
- 2024
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Ingår i: Nuclear Fusion. - : Institute of Physics (IOP). - 0029-5515 .- 1741-4326. ; 64:1
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Tidskriftsartikel (refereegranskat)abstract
- The Joint European Torus (JET) has recently conducted its second deuterium-tritium (DT) experimental campaign DTE2, providing unique opportunity for studying both physics and engineering aspects of nuclear fusion plasmas. This also allowed the exploitation of new diagnostics and technologies that were not available during the first JET DT campaign held in 1997. Among these new instruments, the enhancement projects of the JET nuclear diagnostics lead to the development and installation of synthetic single crystal diamond detectors along different collimated line of sights. This paper describes the single crystal diamond-based diagnostic suite of the JET tokamak and the enhanced 14 MeV neutron diagnostic capabilities in terms of neutron yield and high resolution neutron spectroscopy. The diamond characterization measurements and the calibration procedure at JET are shown, together with performance of the diamond based neutron spectrometer as 14 MeV neutron yield monitor which allows the separation of 2.5 MeV and 14 MeV neutrons in trace tritium plasmas. The first high-resolution 14 MeV neutron spectroscopy measurements in neutral beam injection-heated DT plasmas are presented, allowing thermal and non-thermal neutron component separation. Prospects for the diagnose of DT burning plasmas such as ITER and SPARC will be presented.
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