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- Eriksson, K. G. Peter, et al.
(författare)
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A Simple and Reliable Electrical Method for Measuring the Junction Temperature and Thermal Resistance of 4H-SiC Power Bipolar Junction Transistors
- 2009
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Ingår i: Materials Science Forum. - : Trans Tech Publications Inc.. - 0255-5476 .- 1662-9752. ; 600-603, s. 1171-1174
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Tidskriftsartikel (refereegranskat)abstract
- To determine the maximum allowed power dissipation in a power transistor, it is important to determine the relationship between junction temperature and power dissipation. This work presents a new method for measuring the junction temperature in a SiC bipolar junction transistor (BJT) that is self-heated during DC forward conduction. The method also enables extraction of the thermal resistance between junction and ambient by measurements of the junction temperature as function of DC power dissipation. The basic principle of the method is to determine the temperature dependent IN characteristics of the transistor under pulsed conditions with negligible self-heating, and compare these results with DC measurements with self-heating. Consistent results were obtained from two independent temperature measurements using the temperature dependence of the current gain, and the temperature dependence of the base-emitter IN characteristics, respectively.
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| 2. |
- Erlinge, D., et al.
(författare)
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Bivalirudin versus Heparin Monotherapy in Myocardial Infarction
- 2017
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Ingår i: New England Journal of Medicine. - : Massachusetts Medical Society. - 0028-4793 .- 1533-4406. ; 377:12, s. 1132-1142
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Tidskriftsartikel (refereegranskat)abstract
- Background The comparative efficacy of various anticoagulation strategies has not been clearly established in patients with acute myocardial infarction who are undergoing percutaneous coronary intervention (PCI) according to current practice, which includes the use of radial-artery access for PCI and administration of potent P2Y12 inhibitors without the planned use of glycoprotein IIb/IIIa inhibitors. Methods In this multicenter, randomized, registry-based, open-label clinical trial, we enrolled patients with either ST-segment elevation myocardial infarction (STEMI) or non-STEMI (NSTEMI) who were undergoing PCI and receiving treatment with a potent P2Y12 inhibitor (ticagrelor, prasugrel, or cangrelor) without the planned use of glycoprotein IIb/IIIa inhibitors. The patients were randomly assigned to receive bivalirudin or heparin during PCI, which was performed predominantly with the use of radial-artery access. The primary end point was a composite of death from any cause, myocardial infarction, or major bleeding during 180 days of follow-up. Results A total of 6006 patients (3005 with STEMI and 3001 with NSTEMI) were enrolled in the trial. At 180 days, a primary end-point event had occurred in 12.3% of the patients (369 of 3004) in the bivalirudin group and in 12.8% (383 of 3002) in the heparin group (hazard ratio, 0.96; 95% confidence interval [CI], 0.83 to 1.10; P=0.54). The results were consistent between patients with STEMI and those with NSTEMI and across other major subgroups. Myocardial infarction occurred in 2.0% of the patients in the bivalirudin group and in 2.4% in the heparin group (hazard ratio, 0.84; 95% CI, 0.60 to 1.19; P=0.33), major bleeding in 8.6% and 8.6%, respectively (hazard ratio, 1.00; 95% CI, 0.84 to 1.19; P=0.98), definite stent thrombosis in 0.4% and 0.7%, respectively (hazard ratio, 0.54; 95% CI, 0.27 to 1.10; P=0.09), and death in 2.9% and 2.8%, respectively (hazard ratio, 1.05; 95% CI, 0.78 to 1.41; P=0.76). Conclusions Among patients undergoing PCI for myocardial infarction, the rate of the composite of death from any cause, myocardial infarction, or major bleeding was not lower among those who received bivalirudin than among those who received heparin monotherapy. (Funded by the Swedish Heart-Lung Foundation and others; VALIDATE-SWEDEHEART ClinicalTrialsRegister.eu number, 2012-005260-10 ; ClinicalTrials.gov number, NCT02311231 .).
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| 5. |
- Ashman Kröönström, Linda, 1982, et al.
(författare)
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Exercise capacity, physical activity, and health-related quality of life in adults with CHD
- 2020
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Ingår i: Cardiology in the Young. - 1047-9511 .- 1467-1107. ; 30:5, s. 668-673
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The aim of this study was to assess exercise capacity, physical activity, and health-related quality of life within a broad and unselected group of adults with CHD.Design: From April 2009 to February 2014, 1310 patients were assessed for suitability to participate in this single-centre cross-sectional study. Seven hundred and forty-seven (57%) patients were included, performed a submaximal bicycle test, and answered questionnaires regarding physical activity and health-related quality of life. Exercise capacity, physical activity, and health-related quality of life were compared with reference values and correlations were studied.Results: The exercise capacities of men and women with CHD were 58.7 and 66.3%, respectively, of reference values. Approximately, 20-25% of the patients did not achieve the recommended amount of physical activity. In addition, men scored significantly less points on 7 out of 10 scales of health-related quality of life and women in 6 out of 10 scales, compared with reference values. The strongest correlation was between exercise capacity and the Short Form-36 (physical function).Conclusions: Exercise capacity was impaired in all adults with CHD, including those with less complicated CHD. One-quarter of the patients did not achieve the recommended levels of physical activity. Exercise tests followed by individualised exercise prescriptions may be offered to all patients with CHD aiming to increase exercise capacity, levels of physical activity, improve health-related quality of life, and reduce the risk of acquired life-style diseases.
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| 8. |
- Ashman Kröönström, Linda, 1982, et al.
(författare)
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Muscle function in adults with congenital heart disease
- 2014
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Ingår i: International Journal of Cardiology. - : Elsevier BV. - 0167-5273. ; 170:3, s. 358-363
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The aim was to assess muscle function in a sample of Swedish adult men and women with congenital heart disease (ACHD) and to compare the results with published reference values in healthy adults. METHODS AND RESULTS: From April 2009 to December 2010, 762 adult outpatients were assessed for their suitability and individual need for tests of physical fitness. The patients performed five muscle function tests, two isotonic tests and three isometric tests. Of the 762 patients, 315 (41.3%) patients performed the tests. Patients with ACHD had lower isotonic muscle function compared to healthy reference values. In the heel lift test, men with ACHD performed at 63% and women at 58% of the healthy reference values and in the shoulder flexion test the corresponding performance level was 60% for men with ACHD and 85% for the women. Multiple regression analyses showed that NYHA class II-IV was a significant predictor for a lower isotonic muscle function i.e. heel lift in women (p<0.001) and men (p=0.05) and in shoulder flexion (p<0.001) in women, as well as in isometric knee extension (p=0.04) and isometric shoulder abduction (p<0.001) in women. CONCLUSION: This is the first report of muscle function in a broad and unselected group of patients with ACHD. Our data shows that patients with ACHD have lower isotonic muscle function. The impacts of low muscle function in activities of daily living and the question of whether muscle function could be improved with exercise training need further investigation.
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| 9. |
- Ashman Kröönström, Linda, 1982, et al.
(författare)
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Post-operative musculoskeletal outcomes in patients with coarctation of the aorta following different surgical approaches.
- 2021
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Ingår i: International journal of cardiology. - : Elsevier BV. - 1874-1754 .- 0167-5273. ; 327, s. 80-85
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to examine range of motion and muscle function in the upper extremity and spine in patients with coarctation of the aorta (CoA) comparing different surgical approaches.From October 2017 to February 2019, 150 patients were assessed for inclusion. A total of 99 patients (n=75 CoA, n=24 control), were included and assessed regarding muscle function, arm length and circumference, and spinal and thoracic mobility.There were significant differences between the right and left arm in patients with CoA, operated with the subclavian flap technique compared to controls in regards to shoulder flexion (p<0.001), elbow flexion (p=0.001), shoulder abduction (p=0.02), handgrip strength (p=0.01), length of upper arm (p<0.001), lower arm (p<0.001), and of whole arm (p<0.001), circumference regarding upper arm (p=0.001), lower arm (p<0.001), and wrist (p<0.001). Structural scoliosis was more frequent in patients who had undergone thoracotomy (25.4%) than patients who had not undergone a thoracotomy (5.9%, p=0.04), and were often located in the thoracic part of the spine.Patients with CoA operated on using the subclavian flap technique have impaired muscle function as well as reduced arm length and circumference. An increased rate of structural scoliosis was found in patients who underwent thoracotomy, in comparison with patients who had not undergone a thoracotomy. Further research is needed to determine whether muscle function impaired by surgical procedures can be improved with exercise.
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| 10. |
- Astengo, Marco, et al.
(författare)
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Ability of noninvasive criteria to predict hemodynamically significant aortic obstruction in adults with coarctation of the aorta.
- 2017
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Ingår i: Congenital heart disease. - : Computers, Materials and Continua (Tech Science Press). - 1747-0803 .- 1747-079X. ; 12:2, s. 174-180
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Tidskriftsartikel (refereegranskat)abstract
- Coarctation of the aorta (CoA) is a common condition. Adult patients with newly diagnosed CoA and patients with recurring or residual CoA require evaluation of the severity of aortic obstruction. Cardiac catheterization is considered the gold standard for the evaluation of hemodynamically significant CoA. The European Society of Cardiology (ESC) Guidelines for the management of grown-up congenital heart disease (GUCH) include noninvasive criteria for identifying significant CoA. Our aim was to investigate the ability of the Class I and Class IIa ESC recommendations to identify significant CoA at cardiac catheterization.Sixty-six adult patients with native or recurrent CoA underwent diagnostic cardiac catheterization at the GUCH unit at the Sahlgrenska University Hospital in Gothenburg from October 1998 to November 2013. Clinical and imaging data, as well as data about cardiac catheterization were retrospectively collected from patient records.The Class I ESC recommendations predicted significant CoA with a sensitivity of 0.57, a specificity of 0.63, a positive predictive value of 0.67, and a negative predictive value of 0.53. The combination of Class I and Class IIa recommendations predicted significant CoA with a sensitivity of 0.75, a specificity of 0.42, a positive predictive value of 0.66 and a negative predictive value of 0.52.the noninvasive criteria proposed by the ESC guidelines to identify subjects with significant CoA performed poorly in our dataset. Further research is needed to develop more accurate, noninvasive criteria to evaluate CoA severity and thereby reduce the number of unnecessary cardiac catheterizations.
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