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- Fenstermacher, M.E., et al.
(författare)
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DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
- 2022
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 62:4
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Tidskriftsartikel (refereegranskat)abstract
- DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.
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| 4. |
- Persson, Gabriella, et al.
(författare)
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No evidence for follicular keratinocyte hyperproliferation in acne lesions as compared to autologous healthy hair follicles
- 2018
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Ingår i: Experimental dermatology. - : John Wiley & Sons. - 0906-6705 .- 1600-0625. ; 27:6, s. 668-671
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Tidskriftsartikel (refereegranskat)abstract
- Abnormal hyperkeratinization in sebaceous hair follicles has long been believed to play an important role in acne pathogenesis. Several early reports purported to provide histological evidence for hyperproliferation of keratinocytes in acne lesions by showing a higher expression of the Ki67 as well as certain keratins. The evidence is, however, not robust, and a number of methodological and technical limitations can be identified in these studies. In this study, we looked at the expression of proliferation, mitosis and apoptosis markers directly at acne skin lesions in 66 patients with acne vulgaris. Ki67 was assessed using immunohistochemistry and -tubulin, phospho-histone H3 and cleaved-PARP with immunofluorescence microscopy. Allogenic unaffected hair follicles from the same acne patients were used as an internal control. In both acne and control hair follicles, the -tubulin staining was universal, approaching 100% cells and showed no signs of changed assembly. Expression of cleaved-PARPthe apoptosis markerwas a rare event. Cell proliferation rate measured by the expression of Ki67 and phospho-histone H3 was virtually identical between acne and the two control groups. Our findings show the absence of increased keratinocyte proliferation in acne vulgaris. Alternative mechanisms are likely responsible for infundibular hyperkeratinization in acne pathogenesis.
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