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- 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. |
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| 4. |
- Cookson, MS, et al.
(författare)
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Variation in the definition of biochemical recurrence in patients treated for localized prostate cancer: the American Urological Association Prostate Guidelines for Localized Prostate Cancer Update Panel report and recommendations for a standard in the reporting of surgical outcomes
- 2007
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Ingår i: J Urol. - : Ovid Technologies (Wolters Kluwer Health). ; 177:2, s. 540-545
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Tidskriftsartikel (refereegranskat)abstract
- Purpose The American Urological Association Prostate Guideline Update Panel was charged with updating the Guidelines for Clinically Localized Prostate Cancer. In assessing outcomes with treatment, it became apparent that a highly variable number of definitions exist with respect to biochemical recurrence. Herein, we review the variability in published definitions of biochemical recurrence and make recommendations directed toward improving this terminology by recommending a standard definition in patients treated with radical prostatectomy. Materials and Methods Four PubMed® literature searches were performed between May 2001 and April, 2004 and covered articles published from 1991 through early 2004. The search terms included the MeSH® major headings of prostate cancer and prostatic neoplasm. All potentially relevant articles were retrieved and a more detailed screen for relevance was performed. An article was considered relevant if it reported treatment outcomes of patients with clinical T1 or T2N0M0 prostate cancer. Data extractors recorded the definition of biochemical recurrence and definitions were then collapsed into categories representing the same criteria. The results of biochemical failure were subcategorized by initial treatment. Results Of 13,800 citations, a total of 436 articles were selected. Among these, a total of 145 articles contained 53 different definitions of biochemical recurrence for those treated with radical prostatectomy. Of these, the most common definition (35) was a prostate specific antigen of >0.2 ng/mL or a slight variation thereof. In addition, a total of 208 articles reported 99 different definitions of biochemical failure among those treated with radiation therapy. Of these, the American Society for Therapeutic Radiology and Oncology definition (70) and/or a variation thereof was the most commonly reported. In total, 166 different definitions of biochemical failure were identified. Following radical prostatectomy, the Panel recommends defining biochemical recurrence as an initial serum prostate specific antigen of ≥0.2 ng/mL, with a second confirmatory level of prostate specific antigen of >0.2 ng/mL. The Panel recommends the use of the American Society for Therapeutic Radiology and Oncology criteria for patients treated with radiation therapy and acknowledges that these criteria will soon be updated although not yet published. Conclusions A high degree of variability in the definition of biochemical recurrence exists following treatment for localized prostate cancer. Strict definitions for biochemical recurrence are necessary to identify men at risk for disease progression and to allow meaningful comparisons among patients treated similarly. The Panel acknowledges the American Society for Therapeutic Radiology and Oncology criteria and future modifications thereof for those receiving radiation therapy and recommends the newly developed American Urological Association criteria for those treated with radical prostatectomy. The purpose for the establishment of this standard is for data reporting purposes and for comparison of similarly treated patients. It is not intended to represent a threshold value for which to initiate treatment. The Panel acknowledges that the clinical decision to initiate treatment will be dependent on multiple factors including patient and physician interaction rather than a specific prostate specific antigen threshold value.
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| 5. |
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| 6. |
- Thompson, I, et al.
(författare)
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Guideline for the management of clinically localized prostate cancer: 2007 update.
- 2007
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Ingår i: J Urol. - : Ovid Technologies (Wolters Kluwer Health). ; 177:6, s. 2106-2131
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Previous studies demonstrated a negative correlation between prostate volume and biopsy yield. By decreasing prostate volume 5α-reductase inhibitors may enhance cancer detection, which may explain the greater detection of high grade tumors in the finasteride arm of the Prostate Cancer Prevention Trial. Materials and Methods A mathematical model was constructed to analyze the effects of prostate and tumor volumes, and biopsy core number on cancer detection. The effects of the volume reduction observed with finasteride in the Prostate Cancer Prevention Trial were also modeled, as was the potential reduction in tumor volume needed to explain the observed difference in prostate cancer detection. The model was also applied to the Reduction by Dutasteride of Prostate Cancer Events study. Results A higher number of biopsies are required to ensure a detection probability of 0.90 or greater in larger glands or with smaller tumors. In the Prostate Cancer Prevention Trial for a tumor volume of 1 cc a 17% increase in the detection rate in the finasteride arm would be predicted if there was no change in tumor volume, likewise the rate would be 11% to 17% for the dutasteride arm of the Reduction by Dutasteride of Prostate Cancer Events study. The calculated reduction in tumor volume needed to explain the difference in cancer detection between the finasteride and placebo arms of the Prostate Cancer Prevention Trial would be 51% to 66%. Conclusions This model provides guidance on the optimal number of biopsy cores that accord with an earlier model. These findings also suggest that, if there were no reduction in tumor volume, 5α-reductase inhibitor therapy could lead to excess cancer detection, including high grade tumors.
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