| 1. |
- Abel, I, et al.
(författare)
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Overview of the JET results with the ITER-like wall
- 2013
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10, s. 104002-
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Tidskriftsartikel (refereegranskat)abstract
- Following the completion in May 2011 of the shutdown for the installation of the beryllium wall and the tungsten divertor, the first set of JET campaigns have addressed the investigation of the retention properties and the development of operational scenarios with the new plasma-facing materials. The large reduction in the carbon content (more than a factor ten) led to a much lower Z(eff) (1.2-1.4) during L- and H-mode plasmas, and radiation during the burn-through phase of the plasma initiation with the consequence that breakdown failures are almost absent. Gas balance experiments have shown that the fuel retention rate with the new wall is substantially reduced with respect to the C wall. The re-establishment of the baseline H-mode and hybrid scenarios compatible with the new wall has required an optimization of the control of metallic impurity sources and heat loads. Stable type-I ELMy H-mode regimes with H-98,H-y2 close to 1 and beta(N) similar to 1.6 have been achieved using gas injection. ELM frequency is a key factor for the control of the metallic impurity accumulation. Pedestal temperatures tend to be lower with the new wall, leading to reduced confinement, but nitrogen seeding restores high pedestal temperatures and confinement. Compared with the carbon wall, major disruptions with the new wall show a lower radiated power and a slower current quench. The higher heat loads on Be wall plasma-facing components due to lower radiation made the routine use of massive gas injection for disruption mitigation essential.
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| 2. |
- Romanelli, F, et al.
(författare)
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Overview of the JET results
- 2011
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 51:9
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Tidskriftsartikel (refereegranskat)abstract
- Since the last IAEA Conference JET has been in operation for one year with a programmatic focus on the qualification of ITER operating scenarios, the consolidation of ITER design choices and preparation for plasma operation with the ITER-like wall presently being installed in JET. Good progress has been achieved, including stationary ELMy H-mode operation at 4.5 MA. The high confinement hybrid scenario has been extended to high triangularity, lower ρ*and to pulse lengths comparable to the resistive time. The steady-state scenario has also been extended to lower ρ*and ν*and optimized to simultaneously achieve, under stationary conditions, ITER-like values of all other relevant normalized parameters. A dedicated helium campaign has allowed key aspects of plasma control and H-mode operation for the ITER non-activated phase to be evaluated. Effective sawtooth control by fast ions has been demonstrated with3He minority ICRH, a scenario with negligible minority current drive. Edge localized mode (ELM) control studies using external n = 1 and n = 2 perturbation fields have found a resonance effect in ELM frequency for specific q95values. Complete ELM suppression has, however, not been observed, even with an edge Chirikov parameter larger than 1. Pellet ELM pacing has been demonstrated and the minimum pellet size needed to trigger an ELM has been estimated. For both natural and mitigated ELMs a broadening of the divertor ELM-wetted area with increasing ELM size has been found. In disruption studies with massive gas injection up to 50% of the thermal energy could be radiated before, and 20% during, the thermal quench. Halo currents could be reduced by 60% and, using argon/deuterium and neon/deuterium gas mixtures, runaway electron generation could be avoided. Most objectives of the ITER-like ICRH antenna have been demonstrated; matching with closely packed straps, ELM resilience, scattering matrix arc detection and operation at high power density (6.2 MW m-2) and antenna strap voltages (42 kV). Coupling measurements are in very good agreement with TOPICA modelling. © 2011 IAEA, Vienna.
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| 3. |
- Dunk, Michelle M., et al.
(författare)
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Plasma oxysterols are associated with serum lipids and dementia risk in older women
- 2024
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Ingår i: Alzheimer's & Dementia. - 1552-5260 .- 1552-5279.
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Apolipoprotein E4 (APOE4) carriers’ tendency toward hypercholesterolemia may contribute to Alzheimer's disease (AD) risk through oxysterols, which traverse the blood-brain barrier.METHODS: Relationships between baseline plasma oxysterols, APOE status, serum lipids, and cognitive impairment risk were examined in 328 postmenopausal women from the Women's Health Initiative Memory Study. Women were followed for 25 years or until incident dementia or cognitive impairment.RESULTS: Levels of 24(S)-hydroxycholesterol (24-OHC), 27-hydroxycholesterol (27-OHC), and 24-OHC/27-OHC ratio did not differ by APOE status (p’s > 0.05). Higher 24-OHC and 27-OHC were associated with higher total, low density lipoprotein (LDL), non-high density lipoprotein (HDL), remnant, LDL/HDL, and total/HDL cholesterol and triglycerides (p’s < 0.05). Higher 24-OHC/27-OHC was associated with greater dementia risk (hazard ratio = 1.51, 95% confidence interval:1.02-2.22), which interaction analyses revealed as significant for APOE3 and APOE4+, but not APOE2+ carriers.DISCUSSION: Less favorable lipid profiles were associated with higher oxysterol levels. A higher ratio of 24-OHC/27-OHC may contribute to dementia risk in APOE3 and APOE4+ carriers.
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| 4. |
- Handing, Elizabeth P., et al.
(författare)
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Heterogeneity in association between cognitive function and gait speed among older adults : an integrative data analysis study
- 2021
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Ingår i: The journals of gerontology. Series A, Biological sciences and medical sciences. - : Oxford University Press. - 1079-5006 .- 1758-535X. ; 6:4, s. 710-715
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Tidskriftsartikel (refereegranskat)abstract
- Background: Increasing evidence shows that cognition and gait speed are associated and are important measures of health among older adults. However, previous studies have used different methods to assess these 2 outcomes and lack sufficient sample size to examine heterogeneity among subgroups. This study examined how the relationship between global cognitive function and gait speed are influenced by age, gender, and race utilizing an integrated data analysis approach.Method: Data on cognition (Montreal Cognitive Assessment [MoCA], Mini-Mental Status Examination [MMSE], and Modified Mini-Mental State Examination [3MSE]) and gait speed (range: 4–400 m) were acquired and harmonized from 25 research studies (n = 2802) of adults aged 50+ from the Wake Forest Older American Independence Center. Multilevel regression models examined the relationship between predicted values of global cognitive function (MoCA) and gait speed (4-m walk), including heterogeneity by age, race, and gender.Results: Global cognitive function and gait speed exhibited a consistent positive relationship among whites with increasing age, while this was less consistent for African Americans. That is, there was a low correlation between global cognitive function and gait speed among African Americans aged 50–59, a positive correlation in their 60s and 70s, then a negative correlation thereafter.Conclusion: Global cognition and gait speed exhibited a curvilinear U-shaped relationship among whites; however, the association becomes inverse in African Americans. More research is needed to understand this racial divergence and could aid in identifying interventions to maintain cognitive and gait abilities across subgroups.
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| 5. |
- Luo, Juhua, et al.
(författare)
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Personality traits and diabetes incidence among postmenopausal women.
- 2019
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Ingår i: Menopause (New York, N.Y.). - 1530-0374. ; 26:6, s. 629-636
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Tidskriftsartikel (refereegranskat)abstract
- We examined whether personality traits, including optimism, ambivalence over emotional expressiveness, negative emotional expressiveness, and hostility, were associated with risk of developing type 2 diabetes (hereafter diabetes) among postmenopausal women.A total of 139,924 postmenopausal women without diabetes at baseline (between 1993 and 1998) aged 50 to 79 years from the Women's Health Initiative were prospectively followed for a mean of 14 (range 0.1-23) years. Multivariable Cox proportional hazards regression models were used to assess associations between personality traits and diabetes incidence adjusting for common demographic factors, health behaviors, and depressive symptoms. Personality traits were gathered at baseline using questionnaires. Diabetes during follow-up was assessed via self-report of physician-diagnosed treated diabetes.There were 19,240 cases of diabetes during follow-up. Compared with women in the lowest quartile of optimism (least optimistic), women in the highest quartile (most optimistic) had 12% (hazard ratio [HR], 0.88; 95% confidence interval [CI]: 0.84-0.92) lower risk of incident diabetes. Compared with women in the lowest quartile for negative emotional expressiveness or hostility, women in the highest quartile had 9% (HR, 1.09; 95% CI: 1.05-1.14) and 17% (HR, 1.17; 95% CI: 1.12-1.23) higher risk of diabetes, respectively. The association of hostility with risk of diabetes was stronger among nonobese than obese women.Low optimism and high NEE and hostility were associated with increased risk of incident diabetes among postmenopausal women independent of major health behaviors and depressive symptoms. In addition to efforts to promote healthy behaviors, women's personality traits should be considered to guide clinical or programmatic intervention strategies in diabetes prevention.
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