| 1. |
- Vitos, Levente, et al.
(författare)
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Stainless steel alloys from first-principles theory
- 2011
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Ingår i: 7th European Stainless Steel Conference. - : Associazione Italiana di Metallurgia. - 9788885298842
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Konferensbidrag (refereegranskat)abstract
- Gaining an accurate description of materials obviously requires the most advanced atomic-scale techniques from both experimental and theoretical areas. In spite of the vast number of available techniques, however, the experimental study of the atomic-scale properties and phenomena even in simple solids is rather difficult. In steels the challenges become more complex due to the interplay between the structural, chemical and magnetic effects. On the other hand, advanced computational methods based on density functional theory ensure a proper platform for studying the fundamental properties of steel materials from first-principles. Our group at the Royal Institute of Technology in Stockholm has an international position in developing and applying computational codes for such applications. Using our ab initio tools, we have presented an insight to the electronic and magnetic structure, and micromechanical properties of austenitic stainless steel alloys. In the present contribution, we review the most important developments within the ab initio quantum-mechanics-aided steel design with special emphasis on the role of magnetism on the fundamental properties of alloy steels.
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| 2. |
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| 3. |
- Aksimsek, Sinan, et al.
(författare)
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TEM wave scattering by a step discontinuity on the outer wall of a coaxial waveguide
- 2013
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Ingår i: IEEE transactions on microwave theory and techniques. - : IEEE Press. - 0018-9480 .- 1557-9670. ; 61:8, s. 2783-2791
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the propagation of TEM waves along a coaxial waveguide with a step discontinuity on its outer wall is investigated rigorously by applying the direct Fourier transform and reducing the problem into the solution of a modified Wiener–Hopf equation. The solution for the field terms are determined in terms of an infinite number of unknown coefficients, which satisfy an infinite set of linear algebraic equations. These equations are solved numerically and the effect of area ratio is presented graphically at the end of the analysis. The same problem is also analyzed by applying the mode-matching technique and the results of the two approaches are compared. It is observed numerically that the Wiener–Hopf technique provides a better convergence than the mode-matching technique.
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| 4. |
- Björnson Granqvist, Anna, 1974, et al.
(författare)
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Impaired glomerular and tubular antioxidative defense mechanisms in nephrotic syndrome.
- 2010
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Ingår i: American journal of physiology. Renal physiology. - : American Physiological Society. - 1522-1466 .- 1931-857X. ; 299:4
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Tidskriftsartikel (refereegranskat)abstract
- The molecular mechanisms behind acquired nephrotic syndrome (NS) are still largely unknown. One possible explanation for the development of proteinuria is oxidative damage to the glomerular cells. Our hypothesis was that the oxidative defense is weakened in NS, and we focused on measurements of the oxidative-antioxidative status in the glomerular and tubular parts of the nephron. Gene expression was analyzed in renal biopsies from patients with NS. In addition, to compare the acute and chronic phases of the disease, we studied puromycin-treated rats. In the biopsy material, the expression of enzymes involved in the antioxidative defense was higher in the tubulointerstitial compartment than in the glomerular cells. Real-time PCR analysis revealed a decreased glomerular expression in nephrotic kidneys for the antioxidant enzymes catalase and glutathione peroxidase-3, and -4. The tubular gene expression was downregulated for catalase, glutathione peroxidase-3, and thioredoxin reductase-1 and -2. The altered gene expression was accompanied by increased lipid peroxidation in urine. In rats, serum concentrations of ascorbyl-free radicals, measured with electron spin resonance, were elevated in the acute phase of the disease, suggesting increased oxidative stress in the circulation. In addition, we saw an increase in the plasma antioxidant capacity combined with a decreased oxidation of proteins in sera from nephrotic rats, but not from humans. In conclusion, there is a marked downregulation of several antioxidative enzymes in nephrotic kidneys, especially in glomerular structures. Our data suggest that oxidative damage to glomerular cells may contribute significantly to the course and prognosis of nephrotic syndrome.
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| 5. |
- Buckland, G., et al.
(författare)
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Adherence to the Mediterranean diet and risk of bladder cancer in the EPIC cohort study
- 2014
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Ingår i: International Journal of Cancer. - : Wiley. - 0020-7136 .- 1097-0215. ; 134:10, s. 2504-2511
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Tidskriftsartikel (refereegranskat)abstract
- There is growing evidence of the protective role of the Mediterranean diet (MD) on cancer. However, to date no epidemiological study has investigated the influence of the MD on bladder cancer. We evaluated the association between adherence to the MD and risk of urothelial cell bladder cancer (UCC), according to tumor aggressiveness, in the European Prospective Investigation into Cancer and Nutrition (EPIC). The analysis included 477,312 participants, recruited from ten European countries between 1991 and 2000. Information from validated dietary questionnaires was used to develop a relative Mediterranean diet score (rMED), including nine dietary components. Cox regression models were used to assess the effect of the rMED on UCC risk, while adjusting for dietary energy and tobacco smoking of any kind. Stratified analyses were performed by sex, BMI, smoking status, European region and age at diagnosis. During an average follow-up of 11 years, 1,425 participants (70.9% male) were diagnosed with a first primary UCC. There was a negative but non-significant association between a high versus low rMED score and risk of UCC overall (HR: 0.84 [95% CI 0.69, 1.03]) and risk of aggressive (HR: 0.88 [95% CI 0.61, 1.28]) and non-aggressive tumors (HR: 0.78 [95% CI 0.54, 1.14]). Although there was no effect modification in the stratified analyses, there was a significant 34% (p = 0.043) decreased risk of UCC in current smokers with a high rMED score. In EPIC, the MD was not significantly associated with risk of UCC, although we cannot exclude that a MD may reduce risk in current smokers. What's new? Urothelial cell carcinoma (UCC) is the most common form of bladder cancer. Previous studies suggested that plasma carotenoids, antioxidants found in fruit and vegetables, were associated with a decreased risk of UCC while a high intake of animal protein was associated with an increased cancer risk. Here, the authors conducted the first study to investigate the association between the Mediterranean diet, a diet rich in fresh fruits and vegetables and low in animal products, and UCC in Europe. They found that adherence to a Mediterranean diet was not significantly associated with UCC, regardless of level of tumour aggressiveness. They point out that these findings are in line with the rather weak evidence for questionnaire-based associations between dietary factors and bladder cancer risk.
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| 6. |
- Fridén, Vincent, 1975, et al.
(författare)
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The glomerular endothelial cell coat is essential for glomerular filtration
- 2011
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Ingår i: Kidney international. - : Elsevier BV. - 1523-1755 .- 0085-2538. ; 79:12, s. 1322-1330
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Tidskriftsartikel (refereegranskat)abstract
- The endothelial cell surface layer (ESL) is believed to contribute to the glomerular barrier, and the nature of its molecular structure is still largely unknown. The ESL consists of the membrane-bound glycocalyx and the loosely attached endothelial cell coat (ECC). A brief injection of hypertonic sodium chloride into the left renal artery was used to displace, elute, and collect non-covalently bound components of the renal ESL in rats. This procedure increased the fractional clearance of albumin 12-fold without detectable morphological changes as assessed by electron microscopy compared with the control group injected with isotonic saline. Mathematical modeling suggested a reduced glomerular charge density. Mass spectrometry of the renal eluate identified 17 non-covalently bound proteins normally present in the ECC. One of these proteins, orosomucoid, has previously been shown to be important for capillary permselectivity. Another protein, lumican, is expressed by glomerular endothelial cells and likely contributes to maintaining an intact barrier. Thus, the absence of one or more of these proteins causes proteinuria and illustrates the importance of the ECC in glomerular permselectivity.Kidney International advance online publication, 16 March 2011; doi:10.1038/ki.2011.58.
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| 7. |
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| 8. |
- Gustafsson, Stefan, et al.
(författare)
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Electromagnetic dispersion modeling and measurements for HVDC power cables
- 2014
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Ingår i: IEEE Transactions on Power Delivery. - : IEEE Press. - 0885-8977 .- 1937-4208. ; 29:6, s. 2439-2447
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a general framework for electromagnetic (EM) modeling, sensitivity analysis, computation, and measurements regarding the wave propagation characteristics of high-voltage direct-current (HVDC) power cables. The modeling is motivated by the potential use with transient analysis, partial-discharge measurements, fault localization and monitoring, and is focused on very long (10 km or more) HVDC power cables with transients propagating in the low-frequency regime of about 0-100 kHz. An exact dispersion relation is formulated together with a discussion on practical aspects regarding the computation of the propagation constant. Experimental time-domain measurement data from an 80-km-long HVDC power cable are used to validate the electromagnetic model, and a mismatch calibration procedure is devised to account for the connection between the measurement equipment and the cable. Quantitative sensitivity analysis is devised to study the impact of parameter uncertainty on wave propagation characteristics. The sensitivity analysis can be used to study how material choices affect the propagation characteristics, and to indicate which material parameters need to be identified accurately in order to achieve accurate fault localization. The analysis shows that the sensitivity of the propagation constant due to a change in the conductivity in the three metallic layers (the inner conductor, the intermediate lead shield, and the outer steel armor) is comparable to the sensitivity with respect to the permittivity of the insulating layer. Hence, proper modeling of the EM fields inside the metallic layers is crucial in the low-frequency regime of 0-100 kHz.
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| 9. |
- Gustafsson, Stefan, et al.
(författare)
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Electromagnetic dispersion modeling and sensitivity analysis for HVDC power cables
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This paper addresses electromagnetic wave propagation in High Voltage Direct Current (HVDC) power cables. An electromagnetic model, based on long (10 km or more) cables with a frequency range of 0 to 100 kHz, is derived. Relating the frequency to the propagation constant a dispersion relation is formulated using a recursive approach. The propagation constant is found numerically with normalized residue calculation. The paper is concluded with a sensitivity analysis of the propagation constant with respect to the electrical parameters εr (the real relative permittivity) and σ (the conductivity)
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| 10. |
- Hallqvist, Andreas, 1973, et al.
(författare)
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Concurrent cetuximab and radiotherapy after docetaxel-cisplatin induction chemotherapy in stage III NSCLC : Satellite-A phase II study from the Swedish Lung Cancer Study Group
- 2011
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Ingår i: Lung Cancer. - : Elsevier BV. - 0169-5002 .- 1872-8332. ; 71:2, s. 166-172
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Tidskriftsartikel (refereegranskat)abstract
- Background: Several attempts to increase the locoregional control in locally advanced lung cancer including concurrent chemotherapy, accelerated fractionation and dose escalation have been made during the last years. As the EGFR directed antibody cetuximab has shown activity concurrent with radiotherapy in squamous cell carcinoma of the head and neck, as well as in stage IV NSCLC combined with chemotherapy, we wanted to investigate radiotherapy with concurrent cetuximab in locally advanced NSCLC, a tumour type often over expressing the EGF-receptor. Methods: Between February 2006 and August 2007 75 patients in stage Ill NSCLC with good performance status (PS 0 or 1) and adequate lung function (FEV1 > 1.0) were enrolled in this phase II study at eight institutions. Treatment consisted of 2 cycles of induction chemotherapy, docetaxel 75 mg/m(2) and cisplatin 75 mg/m(2) with 3 weeks interval. An initial dose of cetuximab 400 mg/m(2) was given before start of 3D-CRT to 68 Gy with 2 Gy per fraction in 7 weeks concurrent with weekly cetuximab 250 mg/m(2). Toxicity was scored weekly during radiotherapy (CTC 3.0), and after treatment the patients were followed every third month with CT-scans, toxicity scoring and QLQ. Results: Seventy-one patients were eligible for analysis as four were incorrectly enrolled. Histology: adenocarcinoma 49%, squamous cell carcinoma 39% and other NSCLC 12%. The majority had PS 0 (62.5%), median age 62.2 (42-81), 50% were women and 37% had a pre-treatment weight loss > 5%. Toxicity: esophagitis grade 1-2: 72%; grade 3:1.4%. Hypersensitivity reactions grade 3-4: 5.6%. Febrile neutropenia grade 3-4: 15.4%. Skin reactions grade 1-2: 74%; grade 3: 4.2%. Diarrhoea grade 1-2: 38%; grade 3: 11.3%. Pneumonitis grade 1-2: 26.8%; grade 3: 4.2%; grade 5:1.4%. The median follow-up was 39 months for patients alive and the median survival was 17 months with a 1-, 2- and 3-year OS of 66%, 37% and 29% respectively. Until now local or regional failure has occurred in 20 patients and 22 patients have developed distant metastases. Weight loss, PS and stage were predictive for survival in univariate as well as in multivariate analysis. Conclusion: Induction chemotherapy followed by concurrent cetuximab and RT to 68 Gy is clearly feasible with promising survival. Toxicity, e.g. pneumonitis and esophagitis is low compared to most schedules with concurrent chemotherapy. This treatment strategy should be evaluated in a randomised manner vs. concurrent chemoradiotherapy to find out if it is a valid treatment option.
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