| 1. |
- Bouyoucef, S E, et al.
(författare)
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Poster Session 2 : Monday 4 May 2015, 08
- 2015
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Ingår i: European Heart Journal Cardiovascular Imaging. - : Oxford University Press (OUP). - 2047-2404 .- 2047-2412. ; 16 Suppl 1
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Tidskriftsartikel (refereegranskat)
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| 2. |
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| 3. |
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| 4. |
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| 5. |
- Martin, P., et al.
(författare)
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Overview of the RFX fusion science program
- 2011
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 51:9, s. 094023-
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Tidskriftsartikel (refereegranskat)abstract
- This paper summarizes the main achievements of the RFX fusion science program in the period between the 2008 and 2010 IAEA Fusion Energy Conferences. RFX-mod is the largest reversed field pinch in the world, equipped with a system of 192 coils for active control of MHD stability. The discovery and understanding of helical states with electron internal transport barriers and core electron temperature >1.5 keV significantly advances the perspectives of the configuration. Optimized experiments with plasma current up to 1.8 MA have been realized, confirming positive scaling. The first evidence of edge transport barriers is presented. Progress has been made also in the control of first-wall properties and of density profiles, with initial first-wall lithization experiments. Micro-turbulence mechanisms such as ion temperature gradient and micro-tearing are discussed in the framework of understanding gradient-driven transport in low magnetic chaos helical regimes. Both tearing mode and resistive wall mode active control have been optimized and experimental data have been used to benchmark numerical codes. The RFX programme also provides important results for the fusion community and in particular for tokamaks and stellarators on feedback control of MHD stability and on three-dimensional physics. On the latter topic, the result of the application of stellarator codes to describe three-dimensional reversed field pinch physics will be presented.
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| 6. |
- Lorenzini, R., et al.
(författare)
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Self-organized helical equilibria as a new paradigm for ohmically heated fusion plasmas
- 2009
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Ingår i: Nature Physics. - : Springer Science and Business Media LLC. - 1745-2473 .- 1745-2481. ; 5:8, s. 570-574
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Tidskriftsartikel (refereegranskat)abstract
- In the quest for new energy sources, the research on controlled thermonuclear fusion has been boosted by the start of the construction phase of the International Thermonuclear Experimental Reactor (ITER). ITER is based on the tokamak magnetic configuration, which is the best performing one in terms of energy confinement. Alternative concepts are however actively researched, which in the long term could be considered for a second generation of reactors. Here, we show results concerning one of these configurations, the reversed-field pinch (RFP). By increasing the plasma current, a spontaneous transition to a helical equilibrium occurs, with a change of magnetic topology. Partially conserved magnetic flux surfaces emerge within residual magnetic chaos, resulting in the onset of a transport barrier. This is a structural change and sheds new light on the potential of the RFP as the basis for a low-magnetic-field ohmic fusion reactor.
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| 7. |
- Martin, P., et al.
(författare)
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Overview of RFX-mod results
- 2009
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 49:10, s. 104019-
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Tidskriftsartikel (refereegranskat)abstract
- With the exploration of the MA plasma current regime in up to 0.5 s long discharges, RFX-mod has opened new and very promising perspectives for the reversed field pinch (RFP) magnetic configuration, and has made significant progress in understanding and improving confinement and in controlling plasma stability. A big leap with respect to previous knowledge and expectations on RFP physics and performance has been made by RFX-mod since the last 2006 IAEA Fusion Energy Conference. A new self-organized helical equilibrium has been experimentally achieved ( the Single Helical Axis-SHAx-state), which is the preferred state at high current. Strong core electron transport barriers characterize this regime, with electron temperature gradients comparable to those achieved in tokamaks, and by a factor of 4 improvement in confinement time with respect to the standard RFP. RFX-mod is also providing leading edge results on real-time feedback control of MHD instabilities, of general interest for the fusion community.
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| 8. |
- Martin, P., et al.
(författare)
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Overview of the RFX-mod fusion science programme
- 2013
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 53:10, s. 104018-
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Forskningsöversikt (refereegranskat)abstract
- This paper reports the highlights of the RFX-mod fusion science programme since the last 2010 IAEA Fusion Energy Conference. The RFX-mod fusion science programme focused on two main goals: exploring the fusion potential of the reversed field pinch (RFP) magnetic configuration and contributing to the solution of key science and technology problems in the roadmap to ITER. Active control of several plasma parameters has been a key tool in this endeavour. New upgrades on the system for active control of magnetohydrodynamic (MHD) stability are underway and will be presented in this paper. Unique among the existing fusion devices, RFX-mod has been operated both as an RFP and as a tokamak. The latter operation has allowed the exploration of edge safety factor q edge < 2 with active control of MHD stability and studies concerning basic energy and flow transport mechanisms. Strong interaction has continued with the stellarator community in particular on the physics of helical states and on three-dimensional codes.
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| 9. |
- Antoni, V., et al.
(författare)
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Turbulence and anomalous transport in magnetized plasmas : Hints from the reversed field pinch configuration
- 2004
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Ingår i: Contributions to Plasma Physics. - : Wiley. - 0863-1042 .- 1521-3986. ; 44:06-maj, s. 458-464
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Tidskriftsartikel (refereegranskat)abstract
- The properties of plasma turbulence in the outer region of the Reversed Field Pinch experiments RFX and EXTRAP-T2R are reviewed. The statistical properties of fluctuations in the range of scales relevant for transport are presented. The observation of coherent structures emerging from the background turbulence and their interpretation in terms of vortices is reported. The interplay between these structures and the mean ExB flow of the plasma is demonstrated with emphasis to the action on the preferential rotation direction. The effect on the particle transport induced by the background turbulence and by the structures is discussed. Finally the methods tested to control turbulence and to mitigate the related transport are illustrated and discussed.
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| 10. |
- Carbone, V, et al.
(författare)
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Intermittency and turbulence in a magnetically confined fusion plasma
- 2000
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Ingår i: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - : American Physical Society (APS). - 1539-3755 .- 1550-2376. ; 62:1, s. R49-R52
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Tidskriftsartikel (refereegranskat)abstract
- The intermittency of the magnetic turbulence in reversed field pinch plasmas was measured. The probability distribution functions of magnetic field differences were not scale invariant because the wings of these functions were more important as the scales become smaller. This phenomena was identified as a classical signature of intermittency. The scaling laws also appeared very close to the external wall of the confinement device.
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| 11. |
- Carbone, V, et al.
(författare)
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To what extent can dynamical models describe statistical features of turbulent flows?
- 2002
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Ingår i: Europhysics letters. - : IOP Publishing. - 0295-5075 .- 1286-4854. ; 58:3, s. 349-355
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Tidskriftsartikel (refereegranskat)abstract
- Statistical features of "bursty" behaviour in charged and neutral fluid turbulence are compared to statistics of intermittent events in a GOY shell model, and avalanches in different models of Self-Organized Criticality (SOC). It is found that inter-burst times show a power law distribution for turbulent samples and for the shell model, a property which is shared only in a particular case of the running sandpile model. The breakdown of self-similarity generated by isolated events observed in the turbulent samples is well reproduced by the shell model, while it is absent in all SOC models considered. On this base, we conclude that SOC models are not adequate to mimic fluid turbulence, while the GOY shell model constitutes a better candidate to describe the gross features of turbulence.
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| 12. |
- Kittel-Schneider, Sarah, et al.
(författare)
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Non-mental diseases associated with ADHD across the lifespan : Fidgety Philipp and Pippi Longstocking at risk of multimorbidity?
- 2022
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Ingår i: Neuroscience and Biobehavioral Reviews. - : Pergamon Press. - 0149-7634 .- 1873-7528. ; 132, s. 1157-1180
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Forskningsöversikt (refereegranskat)abstract
- Several non-mental diseases seem to be associated with an increased risk of ADHD and ADHD seems to be associated with increased risk for non-mental diseases. The underlying trajectories leading to such brain-body co-occurrences are often unclear - are there direct causal relationships from one disorder to the other, or does the sharing of genetic and/or environmental risk factors lead to their occurring together more frequently or both? Our goal with this narrative review was to provide a conceptual synthesis of the associations between ADHD and non-mental disease across the lifespan. We discuss potential shared pathologic mechanisms and genetic background and treatments in co-occurring diseases. For those co-occurrences for which published studies with sufficient sample sizes exist, meta-analyses have been published by others and we discuss those in detail. We conclude that non-mental diseases are common in ADHD and vice versa and add to the disease burden of the patient across the lifespan. Insufficient attention to such co-occurring conditions may result in missed diagnoses and suboptimal treatment in the affected individuals.
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| 13. |
- Sorriso-Valvo, Luca, et al.
(författare)
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Intermittency in plasma turbulence
- 2001
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Ingår i: Planetary and Space Science. - 0032-0633 .- 1873-5088. ; 49:12, s. 1193-1200
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Tidskriftsartikel (refereegranskat)
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| 14. |
- Van Oost, G., et al.
(författare)
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Turbulent transport reduction by E x B velocity shear during edge plasma biasing : recent experimental results
- 2003
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Ingår i: Plasma Physics and Controlled Fusion. - 0741-3335 .- 1361-6587. ; 45:5, s. 621-643
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Tidskriftsartikel (refereegranskat)abstract
- Experiments in the tokamaks TEXTOR, CASTOR, T-10 and ISTTOK, as well as in the reversed field pinch RFX have provided new and complementary evidence on the physics of the universal mechanism of E x B velocity shear stabilization of turbulence, concomitant transport barrier formation and radial conductivity by using various edge biasing techniques. In TEXTOR the causality between transport reduction and induced electric fields in the edge has been for the first time clearly demonstrated. The high electric field gradients have been identified as the cause for the quenching of turbulent cells. A quantitative analysis of the measured transport reduction is in good agreement with theoretical predictions. The scaling of plasma turbulence suppression with velocity shear has been established, revealing the density-potential cross-phase as a key element. Reduction in poloidal electric field, temperature, and density fluctuations across the shear layer lead to a reduction of the anomalous conducted and convected heat fluxes resulting in an energy transport barrier that is measured directly. In CASTOR the biasing electrode is placed at the separatrix in a non-intrusive configuration which has demonstrated strongly sheared electric fields and consequent improvement of the global particle confinement, as predicted by theory. The impact of sheared E x B flow on edge turbulent structures has been measured directly using a comprehensive set of electrostatic probe arrays as well as emissive probes. Measurements with a full poloidal Langmuir probe array have revealed quasi-coherent electrostatic waves in the SOL with a dominant mode number equal to the edge safety factor. In T-10 edge biasing is clearly improving the global performance of ECR heated discharges. Reflectometry and heavy ion beam probe measurements show the existence of a narrow plasma layer with strong suppression of turbulence. On ISTTOK, the influence of alternating positive and negative electrode and (non-intrusive) limiter biasing has been compared. Electrode biasing is found to be more efficient in modifying the radial electric field E, and confinement, limiter biasing acting mainly on the SOL. In the RFX reversed field pinch it has been demonstrated that also in RFPs biasing can increase the local E x B velocity shear in the edge region, and hence substantially reduce the local turbulence driven particle flux mainly due to a change in the relative phase between potential and density fluctuations.
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| 15. |
- Zuin, M., et al.
(författare)
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Overview of the RFX-mod fusion science activity
- 2017
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Ingår i: Nuclear Fusion. - : Institute of Physics Publishing (IOPP). - 0029-5515 .- 1741-4326. ; 57:10
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports the main recent results of the RFX-mod fusion science activity. The RFX-mod device is characterized by a unique flexibility in terms of accessible magnetic configurations. Axisymmetric and helically shaped reversed-field pinch equilibria have been studied, along with tokamak plasmas in a wide range of q(a) regimes (spanning from 4 down to 1.2 values). The full range of magnetic configurations in between the two, the so-called ultra-low q ones, has been explored, with the aim of studying specific physical issues common to all equilibria, such as, for example, the density limit phenomenon. The powerful RFX-mod feedback control system has been exploited for MHD control, which allowed us to extend the range of experimental parameters, as well as to induce specific magnetic perturbations for the study of 3D effects. In particular, transport, edge and isotope effects in 3D equilibria have been investigated, along with runaway mitigations through induced magnetic perturbations. The first transitions to an improved confinement scenario in circular and D-shaped tokamak plasmas have been obtained thanks to an active modification of the edge electric field through a polarized electrode. The experiments are supported by intense modeling with 3D MHD, gyrokinetic, guiding center and transport codes. Proposed modifications to the RFX-mod device, which will enable further contributions to the solution of key issues in the roadmap to ITER and DEMO, are also briefly presented.
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| 16. |
- Anchordoqui, Luis A., et al.
(författare)
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The Forward Physics Facility : Sites, experiments, and physics potential
- 2022
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Ingår i: Physics reports. - : Elsevier. - 0370-1573 .- 1873-6270. ; 968, s. 1-50
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Tidskriftsartikel (refereegranskat)abstract
- The Forward Physics Facility (FPF) is a proposal to create a cavern with the space and infrastructure to support a suite of far-forward experiments at the Large Hadron Collider during the High Luminosity era. Located along the beam collision axis and shielded from the interaction point by at least 100 m of concrete and rock, the FPF will house experiments that will detect particles outside the acceptance of the existing large LHC experiments and will observe rare and exotic processes in an extremely low-background environment. In this work, we summarize the current status of plans for the FPF, including recent progress in civil engineering in identifying promising sites for the FPF and the experiments currently envisioned to realize the FPF's physics potential. We then review the many Standard Model and new physics topics that will be advanced by the FPF, including searches for long-lived particles, probes of dark matter and dark sectors, high-statistics studies of TeV neutrinos of all three flavors, aspects of perturbative and non-perturbative QCD, and high-energy astroparticle physics.
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| 17. |
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| 18. |
- Antoni, V., et al.
(författare)
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Coherent structures and anomalous transport in reversed field pinch plasmas
- 2006
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Ingår i: Physica Scripta. - 0031-8949 .- 1402-4896. ; T122, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- The results leading to the identification of coherent structures emerging from the background turbulence in the edge region of the reversed field pinch experiments EXTRAP-T2R and RFX are reviewed. These structures have traits of vortices in velocity field and blobs in density, and the reconstruction of their spatial structure and of their time evolution is discussed focusing on the analysis tools applied. The role of these structures in the particle anomalous transport is addressed, showing that their collisions can contribute up to 50% the total particle losses. This process is shown to be responsible for bursts in particle flux and it is found to set a characteristic collision time, which is in agreement with the statistical properties of laminar times for particle flux bursts.
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| 19. |
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| 20. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 21. |
- Bousquet, J. Jean, et al.
(författare)
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Next-generation ARIA care pathways for rhinitis and asthma : a model for multimorbid chronic diseases
- 2019
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Ingår i: Clinical and Translational Allergy. - : BMC. - 2045-7022. ; 9
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Forskningsöversikt (refereegranskat)abstract
- Background: In all societies, the burden and cost of allergic and chronic respiratory diseases are increasing rapidly. Most economies are struggling to deliver modern health care effectively. There is a need to support the transformation of the health care system into integrated care with organizational health literacy.Main body: As an example for chronic disease care, MASK (Mobile Airways Sentinel NetworK), a new project of the ARIA (Allergic Rhinitis and its Impact on Asthma) initiative, and POLLAR (Impact of Air POLLution on Asthma and Rhinitis, EIT Health), in collaboration with professional and patient organizations in the field of allergy and airway diseases, are proposing real-life ICPs centred around the patient with rhinitis, and using mHealth to monitor environmental exposure. Three aspects of care pathways are being developed: (i) Patient participation, health literacy and self-care through technology-assisted "patient activation", (ii) Implementation of care pathways by pharmacists and (iii) Next-generation guidelines assessing the recommendations of GRADE guidelines in rhinitis and asthma using real-world evidence (RWE) obtained through mobile technology. The EU and global political agendas are of great importance in supporting the digital transformation of health and care, and MASK has been recognized by DG Sante as a Good Practice in the field of digitally-enabled, integrated, person-centred care.Conclusion: In 20 years, ARIA has considerably evolved from the first multimorbidity guideline in respiratory diseases to the digital transformation of health and care with a strong political involvement.
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| 22. |
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| 23. |
- Chen, Zhishan, et al.
(författare)
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Fine-mapping analysis including over 254 000 East Asian and European descendants identifies 136 putative colorectal cancer susceptibility genes
- 2024
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have identified more than 200 common genetic variants independently associated with colorectal cancer (CRC) risk, but the causal variants and target genes are mostly unknown. We sought to fine-map all known CRC risk loci using GWAS data from 100,204 cases and 154,587 controls of East Asian and European ancestry. Our stepwise conditional analyses revealed 238 independent association signals of CRC risk, each with a set of credible causal variants (CCVs), of which 28 signals had a single CCV. Our cis-eQTL/mQTL and colocalization analyses using colorectal tissue-specific transcriptome and methylome data separately from 1299 and 321 individuals, along with functional genomic investigation, uncovered 136 putative CRC susceptibility genes, including 56 genes not previously reported. Analyses of single-cell RNA-seq data from colorectal tissues revealed 17 putative CRC susceptibility genes with distinct expression patterns in specific cell types. Analyses of whole exome sequencing data provided additional support for several target genes identified in this study as CRC susceptibility genes. Enrichment analyses of the 136 genes uncover pathways not previously linked to CRC risk. Our study substantially expanded association signals for CRC and provided additional insight into the biological mechanisms underlying CRC development.
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| 24. |
- Docherty, Anna R, et al.
(författare)
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GWAS Meta-Analysis of Suicide Attempt: Identification of 12 Genome-Wide Significant Loci and Implication of Genetic Risks for Specific Health Factors.
- 2023
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Ingår i: The American journal of psychiatry. - : American Psychiatric Association Publishing. - 1535-7228 .- 0002-953X. ; 180:10, s. 723-738
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Tidskriftsartikel (refereegranskat)abstract
- Suicidal behavior is heritable and is a major cause of death worldwide. Two large-scale genome-wide association studies (GWASs) recently discovered and cross-validated genome-wide significant (GWS) loci for suicide attempt (SA). The present study leveraged the genetic cohorts from both studies to conduct the largest GWAS meta-analysis of SA to date. Multi-ancestry and admixture-specific meta-analyses were conducted within groups of significant African, East Asian, and European ancestry admixtures.This study comprised 22 cohorts, including 43,871 SA cases and 915,025 ancestry-matched controls. Analytical methods across multi-ancestry and individual ancestry admixtures included inverse variance-weighted fixed-effects meta-analyses, followed by gene, gene-set, tissue-set, and drug-target enrichment, as well as summary-data-based Mendelian randomization with brain expression quantitative trait loci data, phenome-wide genetic correlation, and genetic causal proportion analyses.Multi-ancestry and European ancestry admixture GWAS meta-analyses identified 12 risk loci at p values <5×10-8. These loci were mostly intergenic and implicated DRD2, SLC6A9, FURIN, NLGN1, SOX5, PDE4B, and CACNG2. The multi-ancestry SNP-based heritability estimate of SA was 5.7% on the liability scale (SE=0.003, p=5.7×10-80). Significant brain tissue gene expression and drug set enrichment were observed. There was shared genetic variation of SA with attention deficit hyperactivity disorder, smoking, and risk tolerance after conditioning SA on both major depressive disorder and posttraumatic stress disorder. Genetic causal proportion analyses implicated shared genetic risk for specific health factors.This multi-ancestry analysis of suicide attempt identified several loci contributing to risk and establishes significant shared genetic covariation with clinical phenotypes. These findings provide insight into genetic factors associated with suicide attempt across ancestry admixture populations, in veteran and civilian populations, and in attempt versus death.
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| 25. |
- Franke, Barbara, et al.
(författare)
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Live fast, die young? A review on the developmental trajectories of ADHD across the lifespan
- 2018
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Ingår i: European Neuropsychopharmacology. - : Elsevier. - 0924-977X .- 1873-7862. ; 28:10, s. 1059-1088
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Forskningsöversikt (refereegranskat)abstract
- Attention-deficit/hyperactivity disorder (ADHD) is highly heritable and the most common neurodevelopmental disorder in childhood. In recent decades, it has been appreciated that in a substantial number of cases the disorder does not remit in puberty, but persists into adulthood. Both in childhood and adulthood, ADHD is characterised by substantial comorbidity including substance use, depression, anxiety, and accidents. However, course and symptoms of the disorder and the comorbidities may fluctuate and change over time, and even age of onset in childhood has recently been questioned. Available evidence to date is poor and largely inconsistent with regard to the predictors of persistence versus remittance. Likewise, the development of comorbid disorders cannot be foreseen early on, hampering preventive measures. These facts call for a lifespan perspective on ADHD from childhood to old age. In this selective review, we summarise current knowledge of the long-term course of ADHD, with an emphasis on clinical symptom and cognitive trajectories, treatment effects over the lifespan, and the development of comorbidities. Also, we summarise current knowledge and important unresolved issues on biological factors underlying different ADHD trajectories. We conclude that a severe lack of knowledge on lifespan aspects in ADHD still exists for nearly every aspect reviewed. We encourage large-scale research efforts to overcome those knowledge gaps through appropriately granular longitudinal studies.
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| 26. |
- Gallego, Ana, et al.
(författare)
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Study protocol for a three-arm randomized controlled trial investigating the effectiveness, cost-utility, and physiological effects of a fully self-guided digital Acceptance and Commitment Therapy for Spanish patients with fibromyalgia
- 2024
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Ingår i: Digital Health. - : Sage Publications. - 2055-2076. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Fibromyalgia (FM) is a prevalent pain syndrome with significant healthcare and societal costs. The aim of the SMART-FM-SP study is to determine the effectiveness, cost-utility, and physiological effects in patients with FM of a digital intervention (STANZA (R)) currently marketed in the United States, which delivers smartphone-based, fully self-guided Acceptance and Commitment Therapy (Digital ACT) for treating FM-related symptoms.Methods: A single-site, parallel-group, superiority, randomized controlled trial (RCT) will be conducted, including a total of 360 adults diagnosed with FM. Individuals will be randomly allocated (1:1:1) to treatment as usual (TAU), to TAU plus 12 weeks of treatment with Digital ACT, or to TAU plus 12 weeks of treatment with digital symptom tracking (i.e. FibroST). Participants will be assessed at baseline, post-treatment, and 6-month follow-up. An intention-to-treat analysis using linear mixed models will be computed to analyze the effects of Digital ACT on functional impairment (primary outcome), as measured by the Fibromyalgia Impact Questionnaire Revised at 6 months from the inception of the treatment. Secondary outcomes include impression of change, symptoms of distress, pain catastrophising, quality of life, cost-utility, and selected biomarkers (cortisol and cortisone, immune-inflammatory markers, and FKBP5 gene polymorphisms). The role of ACT-related processes of change will be tested with path analyses.Conclusions: This study is the first RCT that tests Digital ACT for Spanish patients with FM. Results will be important not only for patients and clinicians, but also for policy makers by examining the cost-utility of the app in a public healthcare context.
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| 27. |
- Griffin, M. J., et al.
(författare)
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The Herschel-SPIRE instrument and its in-flight performance
- 2010
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518, s. L3-
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Tidskriftsartikel (refereegranskat)abstract
- The Spectral and Photometric Imaging REceiver (SPIRE), is the Herschel Space Observatory`s submillimetre camera and spectrometer. It contains a three-band imaging photometer operating at 250, 350 and 500 mu m, and an imaging Fourier-transform spectrometer (FTS) which covers simultaneously its whole operating range of 194-671 mu m (447-1550 GHz). The SPIRE detectors are arrays of feedhorn-coupled bolometers cooled to 0.3 K. The photometer has a field of view of 4' x 8', observed simultaneously in the three spectral bands. Its main operating mode is scan-mapping, whereby the field of view is scanned across the sky to achieve full spatial sampling and to cover large areas if desired. The spectrometer has an approximately circular field of view with a diameter of 2.6'. The spectral resolution can be adjusted between 1.2 and 25 GHz by changing the stroke length of the FTS scan mirror. Its main operating mode involves a fixed telescope pointing with multiple scans of the FTS mirror to acquire spectral data. For extended source measurements, multiple position offsets are implemented by means of an internal beam steering mirror to achieve the desired spatial sampling and by rastering of the telescope pointing to map areas larger than the field of view. The SPIRE instrument consists of a cold focal plane unit located inside the Herschel cryostat and warm electronics units, located on the spacecraft Service Module, for instrument control and data handling. Science data are transmitted to Earth with no on-board data compression, and processed by automatic pipelines to produce calibrated science products. The in-flight performance of the instrument matches or exceeds predictions based on pre-launch testing and modelling: the photometer sensitivity is comparable to or slightly better than estimated pre-launch, and the spectrometer sensitivity is also better by a factor of 1.5-2.
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| 28. |
- Hewitt, Dominic, et al.
(författare)
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A hydrodynamic comparison of solution and gas phase proteins and their complexes.
- 2014
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 118:29
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Tidskriftsartikel (refereegranskat)abstract
- The extent to which protein structures are preserved on transfer from solution to gas phase is a central question for native mass spectrometry. Here we compare the collision cross sections (Ω) of a wide range of different proteins and protein complexes (15-500 kDa) with their corresponding Stokes radii (RS). Using these methods, we find that Ω and RS are well correlated, implying overall preservation of protein structure in the gas phase. Accounting for protein hydration, a scaling term is required to bring Ω and RS into parity. Interestingly, the magnitude of this scaling term agrees almost entirely with the drag factor proposed by Millikan. RS were then compared with various different predicted values of Ω taken from their atomic coordinates. We find that many of the approaches used to obtained Ω from atomic coordinates miscalculate the physical sizes of the proteins in solution by as much as 20%. Rescaling of Ω estimated from atomic coordinates may therefore seem appropriate as a general method to bring theoretical values in line with those observed in solution.
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| 29. |
- Huyghe, Jeroen R, et al.
(författare)
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Genetic architectures of proximal and distal colorectal cancer are partly distinct
- 2021
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Ingår i: Gut. - : BMJ Publishing Group Ltd. - 0017-5749 .- 1468-3288. ; 70:7, s. 1325-1334
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Tidskriftsartikel (refereegranskat)abstract
- Objective: An understanding of the etiologic heterogeneity of colorectal cancer (CRC) is critical for improving precision prevention, including individualized screening recommendations and the discovery of novel drug targets and repurposable drug candidates for chemoprevention. Known differences in molecular characteristics and environmental risk factors among tumors arising in different locations of the colorectum suggest partly distinct mechanisms of carcinogenesis. The extent to which the contribution of inherited genetic risk factors for CRC differs by anatomical subsite of the primary tumor has not been examined.Design: To identify new anatomical subsite-specific risk loci, we performed genome-wide association study (GWAS) meta-analyses including data of 48 214 CRC cases and 64 159 controls of European ancestry. We characterised effect heterogeneity at CRC risk loci using multinomial modelling.Results: We identified 13 loci that reached genome-wide significance (p<5×10-8) and that were not reported by previous GWASs for overall CRC risk. Multiple lines of evidence support candidate genes at several of these loci. We detected substantial heterogeneity between anatomical subsites. Just over half (61) of 109 known and new risk variants showed no evidence for heterogeneity. In contrast, 22 variants showed association with distal CRC (including rectal cancer), but no evidence for association or an attenuated association with proximal CRC. For two loci, there was strong evidence for effects confined to proximal colon cancer.Conclusion: Genetic architectures of proximal and distal CRC are partly distinct. Studies of risk factors and mechanisms of carcinogenesis, and precision prevention strategies should take into consideration the anatomical subsite of the tumour.
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| 30. |
- Ipcho, Simon V S, et al.
(författare)
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Transcriptome analysis of Stagonospora nodorum: gene models, effectors, metabolism and pantothenate dispensability.
- 2012
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Ingår i: Molecular Plant Pathology. - : Wiley. - 1464-6722. ; 13:6, s. 531-545
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Tidskriftsartikel (refereegranskat)abstract
- The wheat pathogen Stagonospora nodorum, causal organism of the wheat disease Stagonospora nodorum blotch, has emerged as a model for the Dothideomycetes, a large fungal taxon that includes many important plant pathogens. The initial annotation of the genome assembly included 16 586 nuclear gene models. These gene models were used to design a microarray that has been interrogated with labelled transcripts from six cDNA samples: four from infected wheat plants at time points spanning early infection to sporulation, and two time points taken from growth in artificial media. Positive signals of expression were obtained for 12 281 genes. This represents strong corroborative evidence of the validity of these gene models. Significantly differential expression between the various time points was observed. When infected samples were compared with axenic cultures, 2882 genes were expressed at a higher level in planta and 3630 were expressed more highly in vitro. Similar numbers were differentially expressed between different developmental stages. The earliest time points in planta were particularly enriched in differentially expressed genes. A disproportionate number of the early expressed gene products were predicted to be secreted, but otherwise had no obvious sequence homology to functionally characterized genes. These genes are candidate necrotrophic effectors. We have focused attention on genes for carbohydrate metabolism and the specific biosynthetic pathways active during growth in planta. The analysis points to a very dynamic adjustment of metabolism during infection. Functional analysis of a gene in the coenzyme A biosynthetic pathway showed that the enzyme was dispensable for growth, indicating that a precursor is supplied by the plant.
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| 31. |
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| 32. |
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| 33. |
- Mullins, Niamh, et al.
(författare)
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Dissecting the Shared Genetic Architecture of Suicide Attempt, Psychiatric Disorders, and Known Risk Factors
- 2022
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Ingår i: Biological Psychiatry. - : Elsevier. - 0006-3223 .- 1873-2402. ; 91:3, s. 313-327
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Suicide is a leading cause of death worldwide, and nonfatal suicide attempts, which occur far more frequently, are a major source of disability and social and economic burden. Both have substantial genetic etiology, which is partially shared and partially distinct from that of related psychiatric disorders.METHODS: We conducted a genome-wide association study (GWAS) of 29,782 suicide attempt (SA) cases and 519,961 controls in the International Suicide Genetics Consortium (ISGC). The GWAS of SA was conditioned on psychiatric disorders using GWAS summary statistics via multitrait-based conditional and joint analysis, to remove genetic effects on SA mediated by psychiatric disorders. We investigated the shared and divergent genetic architectures of SA, psychiatric disorders, and other known risk factors.RESULTS: Two loci reached genome-wide significance for SA: the major histocompatibility complex and an intergenic locus on chromosome 7, the latter of which remained associated with SA after conditioning on psychiatric disorders and replicated in an independent cohort from the Million Veteran Program. This locus has been implicated in risk-taking behavior, smoking, and insomnia. SA showed strong genetic correlation with psychiatric disorders, particularly major depression, and also with smoking, pain, risk-taking behavior, sleep disturbances, lower educational attainment, reproductive traits, lower socioeconomic status, and poorer general health. After conditioning on psychiatric disorders, the genetic correlations between SA and psychiatric disorders decreased, whereas those with nonpsychiatric traits remained largely unchanged.CONCLUSIONS: Our results identify a risk locus that contributes more strongly to SA than other phenotypes and suggest a shared underlying biology between SA and known risk factors that is not mediated by psychiatric disorders.
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| 34. |
- Pérez-Aranda, Adrián, et al.
(författare)
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A randomized controlled efficacy trial of mindfulness-based stress reduction compared with an active control group and usual care for fibromyalgia : the EUDAIMON study
- 2019
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Ingår i: Pain. - : Ovid Technologies (Wolters Kluwer Health). - 0304-3959 .- 1872-6623. ; 160:11, s. 2508-2523
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Tidskriftsartikel (refereegranskat)abstract
- Fibromyalgia (FM) syndrome represents a great challenge for clinicians and researchers because the efficacy of currently available treatments is limited. This study examined the efficacy of mindfulness-based stress reduction (MBSR) for reducing functional impairment as well as the role of mindfulness-related constructs as mediators of treatment outcomes for people with FM. Two hundred twenty-five participants with FM were randomized into 3 study arms: MBSR plus treatment-as-usual (TAU), FibroQoL (multicomponent intervention for FM) plus TAU, and TAU alone. The primary endpoint was functional impact (measured with the Fibromyalgia Impact Questionnaire Revised), and secondary outcomes included "fibromyalginess," anxiety and depression, pain catastrophising, perceived stress, and cognitive dysfunction. The differences in outcomes between groups at post-treatment assessment (primary endpoint) and 12-month follow-up were analyzed using linear mixed-effects models and mediational models through path analyses. Mindfulness-based stress reduction was superior to TAU both at post-treatment (large effect sizes) and at follow-up (medium to large effect sizes), and MBSR was also superior to FibroQoL post-treatment (medium to large effect sizes), but in the long term, it was only modestly better (significant differences only in pain catastrophising and fibromyalginess). Immediately post-treatment, the number needed to treat for 20% improvement in MBSR vs TAU and FibroQoL was 4.0 (95% confidence interval [CI] = 2.1-6.5) and 5.0 (95% CI = 2.7-37.3). An unreliable number needed to treat value of 9 (not computable 95% CI) was found for FibroQoL vs TAU. Changes produced by MBSR in functional impact were mediated by psychological inflexibility and the mindfulness facet acting with awareness. These findings are discussed in relation to previous studies of psychological treatments for FM.
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| 35. |
- Puiatti, M. E., et al.
(författare)
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Helical equilibria and magnetic structures in the reversed field pinch and analogies to the tokamak and stellarator
- 2009
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 0741-3335 .- 1361-6587. ; 51:12, s. 124031-
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Tidskriftsartikel (refereegranskat)abstract
- The reversed field pinch configuration is characterized by the presence of magnetic structures both in the core and at the edge: in the core, at high plasma current the spontaneous development of a helical structure is accompanied by the appearance of internal electron transport barriers; at the edge strong pressure gradients, identifying an edge transport barrier, are observed too, related to the position of the field reversal surface. The aim of this paper is the experimental characterization of both the internal and edge transport barriers in relation to the magnetic topology, discussing possible analogies and differences with other confinement schemes.
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| 36. |
- Qian, Frank, et al.
(författare)
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Omega-3 Fatty Acid Biomarkers and Incident Atrial Fibrillation
- 2023
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Ingår i: Journal of the American College of Cardiology. - : Elsevier. - 0735-1097 .- 1558-3597. ; 82:4, s. 336-349
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The relationship between omega-3 fatty acids and atrial fibrillation (AF) remains controversial.OBJECTIVES: This study aimed to determine the prospective associations of blood or adipose tissue levels of eicosa-pentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) with incident AF.METHODS: We used participant-level data from a global consortium of 17 prospective cohort studies, each with baseline data on blood or adipose tissue omega-3 fatty acid levels and AF outcomes. Each participating study conducted a de novo analyses using a prespecified analytical plan with harmonized definitions for exposures, outcome, covariates, and sub-groups. Associations were pooled using inverse-variance weighted meta-analysis.RESULTS: Among 54,799 participants from 17 cohorts, 7,720 incident cases of AF were ascertained after a median 13.3 years of follow-up. In multivariable analysis, EPA levels were not associated with incident AF, HR per interquintile range (ie, the difference between the 90th and 10th percentiles) was 1.00 (95% CI: 0.95-1.05). HRs for higher levels of DPA, DHA, and EPA+DHA, were 0.89 (95% CI: 0.83-0.95), 0.90 (95% CI: 0.85-0.96), and 0.93 (95% CI: 0.87-0.99), respectively.CONCLUSIONS: In vivo levels of omega-3 fatty acids including EPA, DPA, DHA, and EPA+DHA were not associated with increased risk of incident AF. Our data suggest the safety of habitual dietary intakes of omega-3 fatty acids with respect to AF risk. Coupled with the known benefits of these fatty acids in the prevention of adverse coronary events, our study suggests that current dietary guidelines recommending fish/omega-3 fatty acid consumption can be maintained.
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| 37. |
- Regnoli, G., et al.
(författare)
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Observations of toroidicity-induced Alfven eigenmodes in a reversed field pinch plasma
- 2005
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 12:4
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Tidskriftsartikel (refereegranskat)abstract
- High frequency peaks in the spectra of magnetic field signals have been detected at the edge of Extrap-T2R [P. R. Brunsell, H. Bergshker, M. Cecconello, J. R. Drake, R. M. Gravestijn, A. Hedqvist, and J-A. Malmberg, Plasma Phys. Controlled Fusion, 43, 1457 (2001)]. The measured fluctuation is found to be mainly polarized along the toroidal direction, with high toroidal periodicity n and Alfvenic scaling (f proportional to B / root m(i)n(i)). Calculations for, a reversed field pinch plasma predict the existence of an edge resonant, high frequency, high-n number toroidicity-induced Alfven eigenmode with the,observed frequency scaling. In addition, gas puffing experiments show that edge density fluctuations are responsible for the rapid. changes of mode frequency. Finally a coupling with the electron drift turbulence is proposed as drive mechanism for the eigenmode.
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| 38. |
- Sanabria-Mazo, Juan P., et al.
(författare)
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A systematic review of cognitive behavioral therapy-based interventions for comorbid chronic pain and clinically relevant psychological distress
- 2023
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Ingår i: Frontiers in Psychology. - : Frontiers Media S.A.. - 1664-1078. ; 14
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Forskningsöversikt (refereegranskat)abstract
- Objective: Chronic pain frequently co-occurs with clinically relevant psychological distress. A systematic review was conducted to identify the efficacy of cognitive behavioral therapy-based interventions for patients with these comorbid conditions.Methods: The systematic search was carried out in Medline, PsycINFO, Web of Science, and Scopus up to March 18th, 2023. Four reviewers independently conducted screenings, extraction, and quality assessment.Results: Twelve randomized controlled trials and one non-randomized controlled trial involving 1,661 participants that examined the efficacy of Cognitive Behavioral Therapy (nine studies), Mindfulness-based Interventions (three studies), Acceptance and Commitment Therapy (one study), and Behavioral Activation Therapy for Depression (one study) were included. Compared to treatment as usual, six out of eight studies of traditional Cognitive Behavioral Therapy reported significant differences in the reduction of depressive symptoms at post-treatment (d from 1.31 to 0.18) and four out of six at follow-up (d from 0.75 to 0.26); similarly, five out of six reported significant differences in the reduction of anxiety symptoms at post-treatment (d from 1.08 to 0.19) and three out of four at follow-up (d from 1.07 to 0.27). Overall, no significant differences between traditional Cognitive Behavioral Therapy and treatment as usual were reported at post-treatment and follow-up in the studies exploring pain intensity and pain catastrophizing.Conclusion: The available evidence suggests that traditional Cognitive Behavioral Therapy may produce significant benefits for the improvement of depression, anxiety, and quality of life, but not for pain intensity and pain catastrophizing. More evidence is needed to determine the effects of MBI, ACT, and BATD.
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| 39. |
- Sanabria-Mazo, Juan P., et al.
(författare)
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Economic Evaluation of Videoconference Group Acceptance and Commitment Therapy and Behavioral Activation Therapy for Depression Versus Usual Care Among Adults With Chronic Low Back Pain Plus Comorbid Depressive Symptoms
- 2024
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Ingår i: Journal of Pain. - : Elsevier. - 1526-5900 .- 1528-8447. ; 25:7
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Tidskriftsartikel (refereegranskat)abstract
- Chronic pain and depression are frequently comorbid conditions associated with significant health care and social costs. This study examined the cost-utility and cost-effectiveness of videoconference-based group forms of Acceptance and Commitment Therapy (ACT) and Behavioral Activation Therapy for Depression (BATD), as a complement to treatment-as-usual (TAU), for patients with chronic low back pain (CLBP) plus depressive symptoms, compared to TAU alone. A trial-based economic evaluation (n = 234) was conducted from a governmental and health care perspective with a time horizon of 12 months. Primary outcomes were the Brief Pain Inventory-Interference Scale (BPIIS) and Quality Adjusted Life Year. Compared to TAU, ACT achieved a significant reduction in total costs (d = .47), and BATD achieved significant reductions in indirect (d = .61) and total costs (d = .63). Significant improvements in BPI-IS (d = .73 and d = .66, respectively) and Quality Adjusted Life Year scores (d = .46 and d = .28, respectively) were found in ACT and BATD compared to TAU. No significant differences in costs and outcomes were found between ACT and BATD. In the intention-totreat analyses, from the governmental and health care perspective, no significant differences in cost reduction and incremental effects were identified in the comparison between ACT, BATD, and TAU. However, in the complete case analysis, significant incremental effects of ACT (ΔBPI-IS = -1.57 and -1.39, respectively) and BATD (ΔBPI-IS = -1.08 and -1.04, respectively) compared with TAU were observed. In the per-protocol analysis, only the significant incremental effects of ACT (ΔBPI-IS = -1.68 and -1.43, respectively) compared to TAU were detected. In conclusion, ACT and BATD might be efficient options in the management of CLBP plus comorbid depression symptoms as compared to usual care. However, no clear difference was found in the comparison between the 2 active therapies regarding cost-effectiveness or cost-utility.
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| 40. |
- Sanabria-Mazo, Juan P., et al.
(författare)
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Efficacy, cost-utility and physiological effects of Acceptance and Commitment Therapy (ACT) and Behavioural Activation Treatment for Depression (BATD) in patients with chronic low back pain and depression : study protocol of a randomised, controlled trial including mobile-technology-based ecological momentary assessment (IMPACT study)
- 2020
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Ingår i: BMJ Open. - : BMJ. - 2044-6055. ; 10:7
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction The IMPACT study focuses on chronic low back pain (CLBP) and depression symptoms, a prevalent and complex problem that represents a challenge for health professionals. Acceptance and Commitment Therapy (ACT) and Brief Behavioural Activation Treatment for Depression (BATD) are effective treatments for patients with persistent pain and depression, respectively. The objectives of this 12 month, multicentre, randomised, controlled trial (RCT) are (i) to examine the efficacy and cost-utility of adding a group-based form of ACT or BATD to treatment-as-usual (TAU) for patients with CLBP and moderate to severe levels of depressive symptoms; (ii) identify pre-post differences in levels of some physiological variables and (iii) analyse the role of polymorphisms in theFKBP5gene, psychological process measures and physiological variables as mediators or moderators of long-term clinical changes. Methods and analysis Participants will be 225 patients with CLBP and moderate to severe depression symptoms recruited at Parc Sanitari Sant Joan de Deu (St. Boi de Llobregat, Spain) and Hospital del Mar (Barcelona, Spain), randomly allocated to one of the three study arms: TAU vs TAU+ACT versus TAU+BATD. A comprehensive assessment to collect clinical variables and costs will be conducted pretreatment, post-treatment and at 12 months follow-up, being pain interference the primary outcome measure. The following physiological variables will be considered at pretreatment and post-treatment assessments in 50% of the sample: immune-inflammatory markers, hair cortisol and cortisone, serum cortisol, corticosteroid-binding globulin and vitamin D. Polymorphisms in theFKBP5gene (rs3800373, rs9296158, rs1360780, rs9470080 and rs4713916) will be analysed at baseline assessment. Moreover, we will include mobile-technology-based ecological momentary assessment, through the Pain Monitor app, to track ongoing clinical status during ACT and BATD treatments. Linear mixed-effects models using restricted maximum likelihood, and a full economic evaluation applying bootstrapping techniques, acceptability curves and sensitivity analyses will be computed. Ethics and dissemination This study has been approved by the Ethics Committee of the Fundacio Sant Joan de Deu and Hospital del Mar. The results will be actively disseminated through peer-reviewed journals, conference presentations, social media and various community engagement activities.
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| 41. |
- Sanabria-Mazo, Juan P., et al.
(författare)
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Efficacy of Videoconference Group Acceptance and Commitment Therapy (ACT) and Behavioral Activation Therapy for Depression (BATD) for Chronic Low Back Pain (CLBP) Plus Comorbid Depressive Symptoms : A Randomized Controlled Trial (IMPACT Study)
- 2023
-
Ingår i: Journal of Pain. - : Elsevier. - 1526-5900 .- 1528-8447. ; 24:8, s. 1522-1540
-
Tidskriftsartikel (refereegranskat)abstract
- This study examined the efficacy of adding a remote, synchronous, group, videoconferencebased form of acceptance and commitment therapy (ACT) or behavioral activation therapy for depression (BATD) to treatment-as-usual (TAU) in 234 patients with chronic low back pain (CLBP) plus comorbid depressive symptoms. Participants were randomly assigned to ACT, BATD, or TAU. Compared to TAU, ACT produced a significant reduction in pain interference at posttreatment (d = .64) and at follow-up (d = .73). BATD was only superior to TAU at follow-up (d = .66). A significant reduction in pain catastrophizing was reported by patients assigned to ACT and BATD at posttreatment (d = .45 and d = .59, respectively) and at follow-up (d = .59, in both) compared to TAU. Stress was significantly reduced at posttreatment by ACT in comparison to TAU (d = .69). No significant between-group differences were found in depressive or anxiety symptoms. Clinically relevant number needed to treat (NNT) values for reduction in pain interference were obtained at posttreatment (ACT vs TAU = 4) and at follow-up (ACT vs TAU = 3; BATD vs TAU = 5). In both active therapies, improvements in pain interference at follow-up were significantly related to improvements at posttreatment in psychological flexibility. These findings suggest that new forms of cognitive-behavioral therapy are clinically useful in improving pain interference and pain catastrophizing. Further research on evidence-based change processes is required to understand the therapeutic needs of patients with chronic pain and comorbid conditions.Trial number: NCT04140838.Perspective: Group videoconference-based ACT and BATD showed greater efficacy than TAU for reducing pain interference and pain catastrophizing in patients with CLBP plus clinically relevant depression. Psychological flexibility appeared to be the main contributor to treatment effects for both ACT and BATD
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| 42. |
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| 43. |
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| 44. |
- Spolaore, M., et al.
(författare)
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Vortex-induced diffusivity in reversed field pinch plasmas
- 2004
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 93:21
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Tidskriftsartikel (refereegranskat)abstract
- Coherent structures identified in two reversed field pinch experiments are interpreted as a dynamic balance of dipolar and monopolar vortices growing and evolving under the effect of the ExB flow shear. For the first time their contribution to the anomalous transport has been estimated in fusion related plasmas, showing that they can account for up to 50% of the total plasma diffusivity. The experimental findings indicate that the diffusion coefficient associated with the coherent structures depends on the relative population of the two types of vortices and is minimum when the two populations are equal. An interpretative model is proposed to explain this feature.
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| 45. |
- Tovedal, Thomas, et al.
(författare)
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Blood Flow Quantitation by Positron Emission Tomography During Selective Antegrade Cerebral Perfusion
- 2017
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Ingår i: Annals of Thoracic Surgery. - : Elsevier BV. - 0003-4975 .- 1552-6259. ; 103:2, s. 610-616
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Perfusion strategies during aortic surgery usually comprise hypothermic circulatory arrest (HCA), often combined with selective antegrade cerebral perfusion (SACP) or retrograde cerebral perfusion. Cerebral blood flow (CBF) is a fundamental parameter for which the optimal level has not been clearly defined. We sought to determine the CBF at a pump flow level of 6 mL/kg/min, previously shown likely to provide adequate SACP at 20°C in pigs.METHODS: Repeated positron emission tomography (PET) scans were used to quantify the CBF and glucose metabolism throughout HCA and SACP including cooling and rewarming. Eight pigs on cardiopulmonary bypass were assigned to either HCA alone (n = 4) or HCA+SACP (n = 4). The CBF was measured by repeated [(15)O]water PET scans from baseline to rewarming. The cerebral glucose metabolism was examined by [(18)F]fluorodeoxyglucose PET scans after rewarming to 37°C.RESULTS: Cooling to 20°C decreased the cortical CBF from 0.31 ± 0.06 at baseline to 0.10 ± 0.02 mL/cm(3)/min (p = 0.008). The CBF was maintained stable by SACP of 6 mL/kg/min during 45 minutes. After rewarming to 37°C, the mean CBF increased to 0.24 ± 0.07 mL/cm(3)/min, without significant differences between the groups at any time-point exclusive of the HCA period. The net cortical uptake (Ki) of [(18)F]fluorodeoxyglucose after rewarming showed no significant difference between the groups.CONCLUSIONS: Cooling autoregulated the CBF to 0.10 mL/cm(3)/min, and 45 minutes of SACP at 6 mL/kg/min maintained the CBF in the present model. Cerebral glucose metabolism after rewarming was similar in the study groups.
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| 46. |
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| 49. |
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| 50. |
- Vidal, Antoni, et al.
(författare)
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Modelling and simulations of reactor neutron noise induced by mechanical vibrations
- 2022
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Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 177
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Tidskriftsartikel (refereegranskat)abstract
- Mechanical vibrations of core internals are among the main perturbations that induce oscillations in the neutron flux field, also known as neutron noise. In this work, different simulation models for the study of the influence of the mechanical vibrations of fuel assemblies on the neutron flux in the reactor core have been discussed. These methodologies employ the diffusion approximation, with or without a previous homogenization model, to simulate the neutron noise in the time or the frequency domain. The diffusion-based approach is expected to be less accurate in the vicinity of the vibrating fuel assemblies, but correct when considering distances larger than a few diffusion lengths away from the perturbation. All methodologies provide consistent results and can reproduce typical features of the neutron noise induced by mechanical vibrations of core components. First, FEMFFUSION can perform simulations in both the time and frequency domains. Second, CORE SIM + can be used to study various neutron noise scenarios in realistic three-dimensional reactor configurations. The third methodology is centred on using commercial codes as CASMO-5, SIMULATE-3 and SIMULATE-3K. This methodology allows time domain simulations of the neutron noise induced by different neutron noise sources in a nuclear reactor. Finally, a model for time-dependent geometry is implemented for the code system ATHLET/QUABOX-CUBBOX employing a cross-section-based approach for encoding water gap width variations at the reflector.
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