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- 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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2. |
- 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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7. |
- Kuhle, J., et al.
(författare)
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Conversion from clinically isolated syndrome to multiple sclerosis: A large multicentre study
- 2015
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Ingår i: Multiple Sclerosis Journal. - : SAGE Publications. - 1352-4585 .- 1477-0970. ; 21:8, s. 1013-1024
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Tidskriftsartikel (refereegranskat)abstract
- Background and objective: We explored which clinical and biochemical variables predict conversion from clinically isolated syndrome (CIS) to clinically definite multiple sclerosis (CDMS) in a large international cohort. Methods: Thirty-three centres provided serum samples from 1047 CIS cases with at least two years' follow-up. Age, sex, clinical presentation, T2-hyperintense lesions, cerebrospinal fluid (CSF) oligoclonal bands (OCBs), CSF IgG index, CSF cell count, serum 25-hydroxyvitamin D3 (25-OH-D), cotinine and IgG titres against Epstein-Barr nuclear antigen 1 (EBNA-1) and cytomegalovirus were tested for association with risk of CDMS. Results: At median follow-up of 4.31 years, 623 CIS cases converted to CDMS. Predictors of conversion in multivariable analyses were OCB (HR = 2.18, 95% CI = 1.71-2.77, p < 0.001), number of T2 lesions (two to nine lesions vs 0/1 lesions: HR = 1.97, 95% CI = 1.52-2.55, p < 0.001; >9 lesions vs 0/1 lesions: HR = 2.74, 95% CI = 2.04-3.68, p < 0.001) and age at CIS (HR per year inversely increase = 0.98, 95% CI = 0.98-0.99, p < 0.001). Lower 25-OH-D levels were associated with CDMS in univariable analysis, but this was attenuated in the multivariable model. OCB positivity was associated with higher EBNA-1 IgG titres. Conclusions: We validated MRI lesion load, OCB and age at CIS as the strongest independent predictors of conversion to CDMS in this multicentre setting. A role for vitamin D is suggested but requires further investigation.
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9. |
- Hensiek, A E, et al.
(författare)
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Familial effects on the clinical course of multiple sclerosis.
- 2007
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Ingår i: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 1526-632X .- 0028-3878. ; 68:5, s. 376-83
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Familial factors influence susceptibility to multiple sclerosis (MS) but it is unknown whether there are additional effects on the natural history of the disease. METHOD: We evaluated 1,083 families with > or =2 first-degree relatives with MS for concordance of age at onset, clinical course, and disease severity and investigated transmission patterns of these clinical features in affected parent-child pairs. RESULTS: There is concordance for age at onset for all families (correlation coefficient 0.14; p < 0.001), as well as for affected siblings (correlation coefficient 0.15; p < 0.001), and affected parent-child pairs (correlation coefficient 0.12; p = 0.03) when each is evaluated separately. Concordance for year of onset is present among affected siblings (correlation coefficient 0.18; p < 0.001) but not the parent-child group (correlation coefficient 0.08; p = 0.15). The clinical course is similar between siblings (kappa 0.12; p < 0.001) but not affected parents and their children (kappa -0.04; p = 0.09). This influence on the natural history is present in all clinical subgroups of relapsing-remitting, and primary and secondary progressive MS, reflecting a familial effect on episodic and progressive phases of the disease. There is no concordance for disease severity within any of the considered family groups (correlation coefficients: all families analyzed together, 0.02, p = 0.53; affected sibling group, 0.02, p = 0.61; affected parent-child group, 0.02, p = 0.69). Furthermore, there are no apparent transmission patterns of any of the investigated clinical features in affected parent-child pairs and no evidence for anticipation or effects of genetic loading. CONCLUSION: Familial factors do not significantly affect eventual disease severity. However, they increase the probability of a progressive clinical course, either from onset or after a phase of relapsing remitting disease. The familial effect is more likely to reflect genetic than environmental conditions. The results are relevant for counseling patients and have implications for the design of studies seeking to identify factors that influence the natural history of the disease.
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11. |
- Lukács, M., et al.
(författare)
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KYNA analogue SZR72 modifies CFA-induced dural inflammation- regarding expression of pERK1/2 and IL-1β in the rat trigeminal ganglion
- 2016
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Ingår i: Journal of Headache and Pain. - : Springer Science and Business Media LLC. - 1129-2369 .- 1129-2377. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Neurogenic inflammation has for decades been considered an important part of migraine pathophysiology. In the present study, we asked the question if administration of a novel kynurenic acid analogue (SZR72), precursor of an excitotoxin antagonist and anti-inflammatory substance, can modify the neurogenic inflammatory response in the trigeminal ganglion. Methods: Inflammation in the trigeminal ganglion was induced by local dural application of Complete Freunds Adjuvant (CFA). Levels of phosphorylated MAP kinase pERK1/2 and IL-1β expression in V1 region of the trigeminal ganglion were investigated using immunohistochemistry and Western blot. Findings: Pretreatment with one dose of SZR72 abolished the CFA-induced pERK1/2 and IL-1β activation in the trigeminal ganglion. No significant change was noted in case of repeated treatment with SZR72 as compared to a single dose. Conclusions: This is the first study that demonstrates that one dose of KYNA analog before application of CFA can give anti-inflammatory response in a model of trigeminal activation, opening a new line for further investigations regarding possible effects of KYNA derivates.
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13. |
- Fuvesi, J., et al.
(författare)
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Proteomic Analysis of Cerebrospinal Fluid in a Fulminant Case of Multiple Sclerosis
- 2012
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 13:6, s. 7676-7693
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Tidskriftsartikel (refereegranskat)abstract
- Multiple Sclerosis (MS) is a chronic disease, but in rare fulminant cases rapid progression may lead to death shortly after diagnosis. Currently there is no diagnostic test to predict disease course. The aim of this study was to identify potential biomarkers/proteins related to rapid progression. We present the case history of a 15-year-old male MS patient. Cerebrospinal fluid (CSF) was taken at diagnosis and at the time of rapid progression leading to the patient's death. Using isobaric tag labeling and nanoflow liquid chromatography in conjunction with matrix assisted laser desorption/ionization time of flight tandem mass spectrometry we quantitatively analyzed the protein content of two CSF samples from the patient with fulminant MS as well as one relapsing-remitting (RR) MS patient and one control headache patient, whose CSF analysis was normal. Seventy-eight proteins were identified and seven proteins were found to be more abundant in both fulminant MS samples but not in the RR MS sample compared to the control. These proteins are involved in the immune response, blood coagulation, cell proliferation and cell adhesion. In conclusion, in this pilot study we were able to show differences in the CSF proteome of a rapidly progressing MS patient compared to a more typical clinical form of MS and a control subject.
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14. |
- Lukács, M., et al.
(författare)
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Topical dura mater application of CFA induces enhanced expression of c-fos and glutamate in rat trigeminal nucleus caudalis : attenuated by KYNA derivate (SZR72)
- 2017
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Ingår i: Journal of Headache and Pain. - : Springer Science and Business Media LLC. - 1129-2369 .- 1129-2377. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Migraine is a debilitating neurological disorder where trigeminovascular activation plays a key role. We have previously reported that local application of Complete Freund’s Adjuvant (CFA) onto the dura mater caused activation in rat trigeminal ganglion (TG) which was abolished by a systemic administration of kynurenic acid (KYNA) derivate (SZR72). Here, we hypothesize that this activation may extend to the trigeminal complex in the brainstem and is attenuated by treatment with SZR72. Methods: Activation in the trigeminal nucleus caudalis (TNC) and the trigeminal tract (Sp5) was achieved by application of CFA onto the dural parietal surface. SZR72 was given intraperitoneally (i.p.), one dose prior CFA deposition and repeatedly daily for 7 days. Immunohistochemical studies were performed for mapping glutamate, c-fos, PACAP, substance P, IL-6, IL-1β and TNFα in the TNC/Sp5 and other regions of the brainstem and at the C1-C2 regions of the spinal cord. Results: We found that CFA increased c-fos and glutamate immunoreactivity in TNC and C1-C2 neurons. This effect was mitigated by SZR72. PACAP positive fibers were detected in the fasciculus cuneatus and gracilis. Substance P, TNFα, IL-6 and IL-1β immunopositivity were detected in fibers of Sp5 and neither of these molecules showed any change in immunoreactivity following CFA administration. Conclusion: This is the first study demonstrating that dural application of CFA increases the expression of c-fos and glutamate in TNC neurons. Treatment with the KYNA analogue prevented this expression.
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18. |
- Csáti, A, et al.
(författare)
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Kynurenic acid modulates experimentally induced inflammation in the trigeminal ganglion.
- 2015
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Ingår i: Journal of Headache and Pain. - : Springer Science and Business Media LLC. - 1129-2369 .- 1129-2377. ; 16:99
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Tidskriftsartikel (refereegranskat)abstract
- The trigeminal ganglion (TG) plays a central role in cranial pain. Administration of complete Freund's adjuvant (CFA) into the temporomandibular joint (TMJ) elicits activation of TG. Kynurenic acid (KYNA) is an endogenous excitatory amino acid receptor blocker, which may have an anti-inflammatory effect. We hypothesize that KYNA may reduce CFA-induced activation within the TG.
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19. |
- de la Luna, E., et al.
(författare)
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Exploring the physics of a high-performance H-mode scenario with small ELMs at low collisionality in JET with Be/W wall
- 2024
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 64:9
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Tidskriftsartikel (refereegranskat)abstract
- A new H-mode regime at low density and low edge safety factor (q 95 = 3.2, with Ip = 3 MA) that combines high energy confinement, stationary conditions for density and radiation and small Edge Localized Modes (ELMs) have been found in JET with Be/W wall. Such a regime is achieved by operating without external gas puffing, leading to a decrease in the edge density and a substantial increase in rotation and ion temperature in both the pedestal and the core region. Transport modelling shows a reduction of the turbulence, which starts in the pedestal region and extends into the plasma core, and outward impurity convection, consistent with the improved energy confinement and the lack of W accumulation observed in those conditions. In addition, large type I ELMs, typically found in gas-fuelled plasmas, are replaced by smaller and more frequent ELMs, whose appearance is correlated with a substantial reduction of the pedestal density and its gradient. Pedestals in this operating regime are stable to peeling-ballooning modes, consistent with the lack of large ELMs. This is in contrast to results in unfuelled JET-C plasmas that typically operated at higher pedestal densities and developed low frequency, large type I ELMs, thus pointing to the low density as one of the critical parameters for accessing this small ELMs regime in JET. This small ELMs regime exhibits the same low pedestal collisionality ( nu e,ped & lowast;similar to 0.1 ) expected in ITER and operates at low q 95, thus making it different from other small ELMs regimes that are typically obtained at higher q 95 and higher pedestal collisionality. These features make this newly developed H-mode regime in JET with Be/W wall a valuable tool for exploring the underlying transport, the different mechanisms of turbulence stabilization, as well as the physics associated with the appearance of small ELMs in high-temperature plasmas at ITER relevant pedestal collisionality.
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22. |
- Horvath, L., et al.
(författare)
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Pedestal particle balance studies in JET-ILW H-mode plasmas
- 2023
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 0741-3335 .- 1361-6587. ; 65:4, s. 044003-
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Tidskriftsartikel (refereegranskat)abstract
- JET-ILW type I ELMy H-modes at 2.5 MA/2.8 T with constant NBI heating (23 MW) and gas fuelling rate were performed, utilising edge localised mode (ELM) pacing by vertical kicks and plasma shaping (triangularity, delta) as tools to disentangle the effects of ELMs, inter-ELM transport and edge stability on the pedestal particle balance. In agreement with previous studies, the pedestal confinement improves with increasing delta, mostly due to a significant increase in pedestal density while the ELM frequency (fELM) is decreased. Improved pedestal confinement with increasing delta was observed even when the pedestal MHD stability was degraded artificially by vertical kicks, implying that increased triangularity may favourably affect the inter-ELM pedestal recovery. The workflow developed to quantify the pedestal particle balance uses high time-resolution profile reflectometry to characterise the inter-ELM evolution of the plasma particle content (dN/dt), the NEO drift-kinetic solver to evaluate the neoclassical fluxes and interpretative EDGE2D-EIRENE simulations to estimate the edge particle source. The edge particle source is then constrained by deuterium Balmer-alpha line intensity measurements in the main chamber, which are, however, strongly affected by reflections from the metal walls. The reflections are accounted for by the CHERAB code taking the divertor emission (the brightest light source in the torus) distribution from imaging spectroscopy measurements as input. Our analysis shows that in the second half of the ELM cycle, the volume-integrated particle source is larger than dN/dt, indicating that transport plays a key role in the inter-ELM pedestal recovery.
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23. |
- Lukács, Melinda, et al.
(författare)
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Dural administration of inflammatory soup or Complete Freund's Adjuvant induces activation and inflammatory response in the rat trigeminal ganglion.
- 2015
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Ingår i: Journal of Headache and Pain. - : Springer Science and Business Media LLC. - 1129-2369 .- 1129-2377. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- Migraine is a painful disorder with a huge impact on individual and public health. We hypothesize that migraine pain originates from a central mechanism that results secondarily in hypersensitivity in peripheral afferents associated with the cerebral and cranial blood vessels. It has previously been shown that application of inflammatory or algesic substances onto the dura mater or chemical stimulation of the dural receptive fields causes hypersensitivity to mechanical and thermal stimulation together with direct activation of the TG. We asked whether local inflammation of dura mater induces inflammatory activation in the trigeminal ganglion.
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24. |
- Rajda, Cecilia, et al.
(författare)
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The norepinephrine level is decreased in the lymphocytes of long-term interferon-beta-treated multiple sclerosis patients
- 2006
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Ingår i: MULTIPLE SCLEROSIS. - : SAGE Publications. - 1352-4585 .- 1477-0970. ; 12:3, s. 265-270
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Tidskriftsartikel (refereegranskat)abstract
- The mutual involvement of dopamine and its metabolites in the nervous and immune systems has the potential to provide information on the interaction of these two systems. During a 24-hour period, we used capillary electrophoresis with electrochemical detection to repeatedly measure the intracellular catecholamine concentrations in the peripheral blood lymphocytes of relapsing-remitting multiple sclerosis (RRMS) patients receiving interferon (IFN)-beta-1b ( n = 13), and those of IFN-naïve RRMS patients receiving their first IFN-beta-1a injection ( n = 19) during this study, and compared them with the levels in healthy controls ( n = 12). At baseline, the norepinephrine level was significantly decreased ( P = 0.003) in the long-term IFN MS patients compared with the controls. The Time × Group interactions for dopamine ( P= 0.5854) and norepinephrine ( P = 0.6192) were not significant. The group effects for the individual drugs were P = 0.3529 and 0.1282, respectively. The lower norepinephrine level at baseline in the long-term IFN MS group suggests an immunologically stable phase, in line with our previous findings. This is the first report of the effects of IFN-beta administration on intracellular catecholamines in MS patients. Further studies are necessary to elucidate the immune reactions affected by the catecholamines in MS and to evaluate the roles of these potential immunotransmitters.
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- Valovič, M., et al.
(författare)
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Fuelling of deuterium-tritium plasma by peripheral pellets in JET experiments
- 2024
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 64:7
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Tidskriftsartikel (refereegranskat)abstract
- A baseline scenario of deuterium-tritium (D-T) plasma with peripheral high-field-side fuelling pellets has been produced in JET in order to mimic the situation in ITER. The isotope mix ratio is controlled in order to target the value of 50%-50% by a combination of tritium gas puffing and deuterium pellet injection. Multiple factors controlling the fuelling efficiency of individual pellets are analysed, with the following findings: (1) prompt particle losses due to pellet-triggered edge-localised modes (ELMs) are detected, (2) the plasmoid drift velocity might be smaller than that predicted by simulation, (3) post-pellet particle loss is controlled by transient phases with ELMs.The overall pellet particle flux normalised to the heat flux is similar to that in previous pellet fuelling experiments in AUG and JET.
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