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- Bagni, Tommaso, et al.
(author)
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Modeling Results of the Quench Behavior of a Nb-Ti Canted-Cosine-Theta Corrector Magnet for LHC
- 2024
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In: IEEE transactions on applied superconductivity (Print). - : Institute of Electrical and Electronics Engineers (IEEE). - 1051-8223 .- 1558-2515. ; 34:5, s. 1-5
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Journal article (peer-reviewed)abstract
- A newly designed superconducting magnet of the Canted-Cosine-Theta (CCT) type was developed as a result of a collaboration between Swedish universities (Uppsala and Linneaus) and Swedish industries. This magnet was designed to function as a replacement of the present LHC orbit corrector magnets, which are approaching their end of life due to the radiation load. As a result, the new CCT magnet was developed to be more radiation tolerant and to constitute a one-to-one replacement to the currently installed version, which is a 1 m long 70 mm double aperture dipole magnet. The final magnet, which is currently under construction, will be tested at FREIA laboratory at Uppsala University and generate a magnetic field of 3.3 T and an integrated field of 2.8 Tm at about 85 A. To examine the magnet quench behavior and to identify a suitable quench protection system, the 3D electro-magnetic and thermal behavior of the coil was modeled using the RAT-Raccoon software. Based on the simulation results, a Metrosil varistor was selected to protect the magnet during the test. In this article, we report the results of the numerical analysis. The magnet model is equipped with a spot heater to initialize the quench and the temperature and voltages are monitored during the avalanche effect. The simulated current decay and the hot-spot temperature are analyzed with a focus on the impact of quench-back on the magnet protection.
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| 5. |
- Pepitone, Kevin, Dr, 1988-, et al.
(author)
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Design and Fabrication of a Canted-Cosine-Theta Double Aperture Orbit Corrector Dipole for the LHC
- 2023
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In: IEEE transactions on applied superconductivity (Print). - : IEEE. - 1051-8223 .- 1558-2515. ; 33:5
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Journal article (peer-reviewed)abstract
- A prototype CCT dipole magnet developed by a collaboration between Swedish universities, Swedish industry and CERN will be tested at Uppsala University. This 1 m long double-aperture magnet can provide a field strength of 3.3 T at 85 A in a 70 mm aperture with an integrated field of 2.8 Tm. It is intended to replace the current LHC orbit corrector magnets which are reaching the end of their expected life due to the radiation load. The new magnet is designed to handle the radiation dose of the upgrade to the high-luminosity LHC, which will deliver about ten times the current radiation dose. It must therefore be more resistant to radiation and meet strict requirements in terms of electrical insulation while matching the original field quality and self-protective capability, mechanical volume, and maximum excitation current. This paper will present the latest of the design and manufacturing work, including the results of simulations of the mechanical field and the mechanical stress. Details of the various tests performed before machining the parts are also presented.
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| 6. |
- Vorkapic, Emina, et al.
(author)
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Imatinib treatment attenuates growth and inflammation of angiotensin II induced abdominal aortic aneurysm
- 2016
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In: Atherosclerosis. - : Elsevier BV. - 0021-9150 .- 1879-1484. ; 249, s. 101-109
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Journal article (peer-reviewed)abstract
- AbstractBackground Abdominal aortic aneurysm (AAA) is characterized by vascular remodeling with increased infiltration of inflammatory cells and apoptosis/modulation of vascular smooth muscle cells (SMCs). Imatinib is a selective inhibitor of several tyrosine kinases, including PDGF receptors, Abl, and c-kit. The objective of this study was to characterize the potential protective role of imatinib on AAA development and the molecular mechanisms involved. Methods Male ApoE−/− mice were infused with angiotensin (Ang) II (1000 ng/kg/min) for 4 weeks to induce AAA or saline as controls. Daily treatment with 10 mg/kg imatinib, or tap water as control, was provided via gavage for 4 weeks. Results Treatment with imatinib was found to decrease the aortic diameter and vessel wall thickness, mediated by multiple effects. Imatinib treatment in AngII infused mice resulted in a reduced cellular infiltration of CD3ε positive T lymphocytes by 86% and reduced gene expression of mast cell chymase by 50% compared with AngII infused mice lacking imatinib. Gene expression analysis of SMC marker SM22α demonstrated an increase by 48% together with a more intact medial layer after treatment with imatinib as evaluated with SM22α immunostaining. Conclusion Present findings highlight the importance of tyrosine kinase pathways in the development of AAA. Our results show, that imatinib treatment inhibits essential mast cell, T lymphocyte and SMC mediated processes in experimental AAA. Thus, our results support the idea that tyrosine kinase inhibitors may be useful in the treatment of pathological vascular inflammation and remodeling in conditions like AAA.
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| 7. |
- Vujasinovic, M, et al.
(author)
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Low Bone Mineral Density and Risk for Osteoporotic Fractures in Patients with Chronic Pancreatitis
- 2021
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In: Nutrients. - : MDPI AG. - 2072-6643. ; 13:7
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Journal article (peer-reviewed)abstract
- Introduction: Chronic pancreatitis (CP) can lead to malnutrition, an established risk factor for low bone mineral density (BMD) and fractures. This study aims to determine the prevalence of low BMD, assess fracture incidence and explore risk factors for fractures in patients with CP. Patients and methods: We performed a retrospective analysis of all patients treated for CP at Karolinska University Hospital between January 1999 and December 2020. Electronic medical records were retrieved to assess demographic, laboratory and clinical data. Patients subjected to dual-energy X-ray absorptiometry (DXA) were categorised as either low BMD or normal BMD. We investigated whether the rate of fractures, defined by chart review, differed between these groups using Cox regression, adjusting the model for age, sex and body mass index (BMI). Additional within-group survival analysis was conducted to identify potential risk factors. Results: DXA was performed in 23% of patients with definite CP. Some 118 patients were included in the final analysis. Low BMD was present in 63 (53.4%) patients. Mean age at CP diagnosis in the total cohort was 53.1 years and was significantly lower in patients with normal BMD than in patients with low BMD (45.5 vs. 59.8, p < 0.001). Significant differences were observed in smoking status and disease aetiology, i.e., a higher proportion of patients with low BMD were current or former smokers, with nicotine or alcohol being a more common cause of CP (p < 0.05). Total follow-up time was 898 person-years. Fractures were found in 33 (28.0%) patients: in 5 of 55 patients (16.7%) with normal DXA and in 28 of 63 patients (44.4%) with low BMD (adjusted hazard ratio = 3.4, 95% confidence interval (CI) = 1.2–9.6). Patients with at least 3 months of consecutive pancreatic enzyme replacement therapy (PERT) or vitamin D treatment had a longer median time to fracture after CP diagnosis. Conclusion: DXA was only performed in 23% of patients with definite CP in this study, indicating a low adherence to current European guidelines. A low BMD was found in 53.4% of patients with CP, and 44% of the patients with a low BMD experienced a fracture during follow-up. Moreover, the fracture rate in patients with low BMD increased compared to those with normal BMD.
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