| 1. |
- Christensson, Anders, et al.
(författare)
-
Serum cystatin C is a more sensitive and more accurate marker of glomerular filtration rate than enzymatic measurements of creatinine in renal transplantation.
- 2003
-
Ingår i: Nephron Physiology. - : S. Karger AG. - 1660-2137. ; 94:2, s. 19-27
-
Tidskriftsartikel (refereegranskat)abstract
- <i>Background/Aims:</i> Serum creatinine has several drawbacks as marker of glomerular filtration rate (GFR), and therefore serum cystatin C has been proposed as a more optimal GFR marker. Previous reports have suggested benefits of serum cystatin C measurements in patients with renal transplants. The purpose of the present study was to evaluate the diagnostic accuracy of cystatin C measurements compared with enzymatic creatinine measurements as serum markers of GFR (established from plasma clearance of iohexol) in a large cohort of stable renal transplant recipients and in the early postoperative phase. <i>Methods:</i> Renal transplant patients (n = 125) with stable graft function were evaluated from reciprocals of serum creatinine and cystatin C compared with iohexol clearance. Fourteen patients were examined immediately after the onset of renal function. Cystatin C was measured by a particle-enhanced turbidimetric method and creatinine by an enzymatic method. <i>Results:</i> In stable renal transplant recipients, serum cystatin C showed a significantly (p = 0.033) closer correlation (r = 0.89 or 79% co-variance) with iohexol clearance than did serum creatinine (r = 0.81 or 66% co-variance). Using the χ<sup>2</sup> test and a cut-off at 60 ml/min/1.73 m<sup>2</sup>, serum cystatin C levels demonstrated significantly higher sensitivity for early GFR impairment (p = 0.0045) compared with serum creatinine measurements. On the first day after transplantation, serum cystatin C fell more rapidly than serum creatinine. <i>Conclusion:</i> Serum cystatin C levels correlate significantly closer to accurate measurements of GFR and are significantly more sensitive to detect early GFR impairment than enzymatic measurements of creatinine in serum.
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| 2. |
- Andelid, Kristina, 1953, et al.
(författare)
-
Systemic cytokine signaling via IL-17 in smokers with obstructive pulmonary disease: a link to bacterial colonization?
- 2015
-
Ingår i: International Journal of Chronic Obstructive Pulmonary Disease. - : Informa UK Limited. - 1178-2005. ; 10, s. 689-702
-
Tidskriftsartikel (refereegranskat)abstract
- We examined whether systemic cytokine signaling via interleukin (IL)-17 and growth-related oncogene-alpha (GRO-alpha) is impaired in smokers with obstructive pulmonary disease including chronic bronchitis (OPD-CB). We also examined how this systemic cytokine signaling relates to bacterial colonization in the airways of the smokers with OPD-CB. Currently smoking OPD-CB patients (n=60, corresponding to Global initiative for chronic Obstructive Lung Disease [ GOLD] stage I-IV) underwent recurrent blood and sputum sampling over 60 weeks, during stable conditions and at exacerbations. We characterized cytokine protein concentrations in blood and bacterial growth in sputum. Asymptomatic smokers (n=10) and never-smokers (n=10) were included as control groups. During stable clinical conditions, the protein concentrations of IL-17 and GRO-alpha were markedly lower among OPD-CB patients compared with never-smoker controls, whereas the asymptomatic smoker controls displayed intermediate concentrations. Notably, among OPD-CB patients, colonization by opportunistic pathogens was associated with markedly lower IL-17 and GRO-alpha, compared with colonization by common respiratory pathogens or oropharyngeal flora. During exacerbations in the OPD-CB patients, GRO-alpha and neutrophil concentrations were increased, whereas protein concentrations and messenger RNA for IL-17 were not detectable in a reproducible manner. In smokers with OPD-CB, systemic cytokine signaling via IL-17 and GRO-alpha is impaired and this alteration may be linked to colonization by opportunistic pathogens in the airways. Given the potential pathogenic and therapeutic implications, these findings deserve to be validated in new and larger patient cohorts.
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| 3. |
- Andelid, Kristina, 1953, et al.
(författare)
-
Systemic signs of neutrophil mobilization during clinically stable periods and during exacerbations in smokers with obstructive pulmonary disease
- 2015
-
Ingår i: International Journal of Chronic Obstructive Pulmonary Disease. - : Informa UK Limited. - 1178-2005. ; 10, s. 1253-1263
-
Tidskriftsartikel (refereegranskat)abstract
- Background: It is still unclear whether signs of neutrophil mobilization in the blood of patients with chronic obstructive pulmonary disease represent true systemic events and how these relate to bacterial colonization in the airways. In this study, we evaluated these issues during clinically stable periods and during exacerbations in smokers with obstructive pulmonary disease and chronic bronchitis (OPD-CB). Methods: Over a period of 60 weeks for each subject, blood samples were repeatedly collected from 60 smokers with OPD-CB during clinically stable periods, as well as during and after exacerbations. Myeloperoxidase (MPO) and neutrophil elastase (NE) protein and mRNA, growth of bacteria in sputum, and clinical parameters were analyzed. Ten asymptomatic smokers and ten never-smokers were included as controls. Results: We found that, during clinically stable periods, neutrophil and NE protein concentrations were increased in smokers with OPD-CB and in the asymptomatic smokers when compared with never-smokers. During exacerbations, neutrophil and MPO protein concentrations were further increased in smokers with OPD-CB, without a detectable increase in the corresponding mRNA during exacerbations. However, MPO and NE protein and mRNA displayed positive correlations. During exacerbations, only increased neutrophil concentrations were associated with growth of bacteria in sputum. Among patients with low transcutaneous oxygen saturation during exacerbations, PaO2 (partial oxygen pressure) correlated with concentrations of MPO and NE protein and neutrophils in a negative manner. Conclusion: There are signs of systemic neutrophil mobilization during clinically stable periods and even more so during exacerbations in chronic obstructive pulmonary disease. In this condition, MPO and NE may share a cellular origin, but its location remains uncertain. Factors other than local bacteria, including hypoxemia, may be important for driving systemic signs of neutrophil mobilization.
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| 4. |
- Fridell, Erik, 1963, et al.
(författare)
-
Emissions of particulate matter from railways – onboard and tunnel measurements
- 2009
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- There are increasing concerns about health risks associated with high levels of particulate matter in air. A major source of these particles is combustion engines but also particles originating from wear of material can be important. It is in this context of interest to study particle emissions from railways. A number of studies have reported high concentrations of particles in underground stations and subways. There are few studies reporting levels of particles in railway environments above ground and no studies reporting emission factors or the variability in emissions with driving pattern.In the report a number of measurements of particle emissions from railway are presented. In the first part of the report, results from tunnel measurements where abrasion particles from different types of trains are measured in two campaigns are reported. Further, emission factors are calculated from these measurements. In the second part of the project, measurements were done with instruments positioned under a train. This provided information on how the particle emissions vary with driving patterns.
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| 5. |
- Fridell, Erik, 1963, et al.
(författare)
-
On-board measurements of particulate matter emissions from a passenger train
- 2011
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - 0954-4097 .- 2041-3017. ; 225:1, s. 99-106
-
Tidskriftsartikel (refereegranskat)abstract
- A number of measurements of particle emission from railways are presented. The measurements featured a particle instrument mounted in a compartment under a Regina train. The particles were probed in a volume between the coaches. The measurements were done in two campaigns and provide information on how the particle emissions vary with driving patterns. The measurements showed elevated particle concentrations when the train was running. Further, sharp peaks in the particle concentration were observed. It was noted that these peaks coincided with retardation of the train. However, there are also retardations where no peaks were observed. This can be explained from the two parallel breaking systems, one with regenerative breaking and one with mechanical breaks that are present on the Regina train. It is suggest that the observed peaks coincide with the use of the mechanical breaks. It was not possible to fully establish that increased particle concentration coincides with curvature of the rail, even though this was indicated in parts of the data. The size-resolved data showed maxima for the smallest fraction (350 nm) for the number distribution.
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| 6. |
- Fröidh, Oskar, et al.
(författare)
-
Färdplan för ökad forskning och innovation inom underhåll av järnvägsfordon
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- KTH, Chalmers och Handelshögskolan vid Göteborgs universitet har av Trafikverket fått uppdraget att ta fram ett dokument om forskningen inom underhåll av järnvägsfordon. Det är föreliggande färdplan som ingår i Trafikverkets satsning Morgondagens depåer. Färdplanen ska ligga till grund för en strategi och förslag på utveckling för kostnadseffektivt fordonsunderhåll med de förutsättningar som råder i Sverige, med avreglering och många aktörer i branschen likväl som speciella klimatförutsättningar. Trafikverket har uppmärksammat att frågor om depåer och fordonsunderhåll inte alltid hanteras på ett bra sätt för att utveckla järnvägssystemet. Tidigare hade Banverket ett sektorsansvar men det avskaffades i och med att Trafikverket bildades. Det behövs dock ett övergripande systemansvar och incitament för att leda processen framåt mot en stabil utveckling genom forskning, utveckling och innovation i den fortsatta omreglering som sker av den svenska järnvägssektorn. Hur kan en effektiv samverkan mellan universitet, näringsliv och offentlig sektor utformas för att bidra till en säker och pålitlig tågtrafik i Sverige? En litteraturgenomgång har genomförts för att visa var den internationella forskningsfronten står. Det tycks dock som att det samlade greppet inom underhåll av järnvägsfordon inte är ett genomarbetat forskningsområde, utan det kan bli ett svenskt ”pionjärområde” där universitet, högskolor och institut i samarbete med branschen kan skapa forskningsresultat och kunskapsutveckling. Denna färdplan föreslår ett antal olika områden som skulle behöva ökad forskning för större kunskap och kompetens. Var ska depåer för person- respektive godsfordon mest effektivt lokaliseras, centralt eller perifert i jämförelse med trafiksystemet och respektive omlopp? Hur ska de utformas mest effektivt med tanke på fordonstyper, reservdelar och personalutnyttjande? Hur ska infrastrukturen till och internt i depåerna utformas för effektivt arbete? Detta ska ske i en avreglerad järnvägssektor med olika operatörer, vagnägare, depåägare samt underhållsleverantörer på olika långa kontrakt. Hur ska detta organiseras på ett stabilt sätt med långsiktig ekonomisk bärkraft för samtliga parter? Arbetet går att dela upp i avhjälpande och förebyggande underhåll; i depå eller mobilt, med säkerhets-, drifts- eller komfortrelaterat underhåll. På vilka olika sätt går det att utvärdera samt utveckla modeller för att prognostisera behovet av underhåll enligt ovan nämnda variabler? Målet är att ta fram vetenskapliga metoder för att effektivisera fordonsunderhåll för järnvägstrafiken på ett optimalt sätt. I färdplanen rekommenderas en strategi för fordonsunderhåll: Trafikverket ska verka för att efterfrågad funktion i det svenska järnvägssystemet uppnås, inkluderande kostnadseffektivt underhåll av både infrastruktur och fordon. Hög driftsäkerhet är attraktivt för resenärer och godskunder och har ett värde och motiverar ett samhällsekonomiskt synsätt på underhåll av järnvägsfordon. Tillståndsövervakning och relaterad prediktering ges en viktigare roll för förebyggande underhåll. Öka synergin mellan infrastruktur- och fordonsbaserad tillståndsövervakning, inte minst av den dynamiska samverkan mellan infrastruktur och fordon. Utred hur ”intelligensen” hos infrastruktur och fordon bäst fördelas och utvecklas för ett mera kostnadseffektivt underhåll av järnvägssystemet. Detta innefattar att man vet vad man skall mäta och att uppmätta storheter kan länkas till framtida nedbrytning av fordon och infrastruktur. Utred flödet och ”flaskhalsar” i dagens system av fordonsunderhåll (kritiska aspekter). Utveckla distinktionen av säkerhetsnödvändigt underhåll och komfortrelaterat underhåll. Verka för tydliga och rimliga ”spelregler” för aktörer inom fordonsunderhåll. Förbättra nätverket bland dessa aktörer, inte minst kring tekniska frågor. Skapa ytterligare incitament för effektivt fordonsunderhåll genom att se över kostnader och intäkter i intressentkedjan mellan de primära kunderna och de som kan åtgärda problemen. Lyft fram goda exempel (best practice) på väl fungerande fordonsunderhåll. Låt universitet och högskolor få en viktig och neutral roll i den kunskapsbaserade utvecklingen. Detta bör ske genom att skapa ett forsknings- utvecklings- och demonstrations (FUD)-program inom området underhåll för järnvägsfordon. I denna färdplan föreslås även ett antal olika forskningsprojekt och -områden som skulle kunna utvecklas i ett sammanhållet forskningsprogram.
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| 7. |
- Fröidh, Oskar, et al.
(författare)
-
Färdplan för ökad forskning och innovation inom underhåll av järnvägsfordon
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- KTH, Chalmers och Handelshögskolan vid Göteborgs universitet har av Trafikverket fått uppdraget att ta fram ett dokument om forskningen inom underhåll av järnvägsfordon. Det är föreliggande färdplan som ingår i Trafikverkets satsning Morgondagens depåer. Färdplanen ska ligga till grund för en strategi och förslag på utveckling för kostnadseffektivt fordonsunderhåll med de förutsättningar som råder i Sverige, med avreglering och många aktörer i branschen likväl som speciella klimatförutsättningar.Trafikverket har uppmärksammat att frågor om depåer och fordonsunderhåll inte alltid hanteras på ett bra sätt för att utveckla järnvägssystemet. Tidigare hade Banverket ett sektorsansvar men det avskaffades i och med att Trafikverket bildades. Det behövs dock ett övergripande systemansvar och incitament för att leda processen framåt mot en stabil utveckling genom forskning, utveckling och innovation i den fortsatta omreglering som sker av den svenska järnvägssektorn. Hur kan en effektiv samverkan mellan universitet, näringsliv och offentlig sektor utformas för att bidra till en säker och pålitlig tågtrafik i Sverige?En litteraturgenomgång har genomförts för att visa var den internationella forskningsfronten står. Det tycks dock som att det samlade greppet inom underhåll av järnvägsfordon inte är ett genomarbetat forskningsområde, utan det kan bli ett svenskt ”pionjärområde” där universitet, högskolor och institut i samarbete med branschen kan skapa forskningsresultat och kunskapsutveckling.Denna färdplan föreslår ett antal olika områden som skulle behöva ökad forskning för större kunskap och kompetens. Var ska depåer för person- respektive godsfordon mest effektivt lokaliseras, centralt eller perifert i jämförelse med trafiksystemet och respektive omlopp? Hur ska de utformas mest effektivt med tanke på fordonstyper, reservdelar och personalutnyttjande? Hur ska infrastrukturen till och internt i depåerna utformas för effektivt arbete? Detta ska ske i en avreglerad järnvägssektor med olika operatörer, vagnägare, depåägare samt underhållsleverantörer på olika långa kontrakt. Hur ska detta organiseras på ett stabilt sätt med långsiktig ekonomisk bärkraft för samtliga parter? Arbetet går att dela upp i avhjälpande och förebyggande underhåll; i depå eller mobilt, med säkerhets-, drifts- eller komfortrelaterat underhåll. På vilka olika sätt går det att utvärdera samt utveckla modeller för att prognostisera behovet av underhåll enligt ovan nämnda variabler? Målet är att ta fram vetenskapliga metoder för att effektivisera fordonsunderhåll för järnvägstrafiken på ett optimalt sätt.I färdplanen rekommenderas en strategi för fordonsunderhåll:Trafikverket ska verka för att efterfrågad funktion i det svenska järnvägssystemet uppnås, inkluderande kostnadseffektivt underhåll av både infrastruktur och fordon.Hög driftsäkerhet är attraktivt för resenärer och godskunder och har ett värde och motiverar ett samhällsekonomiskt synsätt på underhåll av järnvägsfordon.Tillståndsövervakning och relaterad prediktering ges en viktigare roll för förebyggande underhåll.Öka synergin mellan infrastruktur- och fordonsbaserad tillståndsövervakning, inte minst av den dynamiska samverkan mellan infrastruktur och fordon.Utred hur ”intelligensen” hos infrastruktur och fordon bäst fördelas och utvecklas för ett mera kostnadseffektivt underhåll av järnvägssystemet. Detta innefattar att man vet vad man skall mäta och att uppmätta storheter kan länkas till framtida nedbrytning av fordon och infrastruktur.Utred flödet och ”flaskhalsar” i dagens system av fordonsunderhåll (kritiska aspekter).Utveckla distinktionen av säkerhetsnödvändigt underhåll och komfortrelaterat underhåll.Verka för tydliga och rimliga ”spelregler” för aktörer inom fordonsunderhåll.Förbättra nätverket bland dessa aktörer, inte minst kring tekniska frågor.Skapa ytterligare incitament för effektivt fordonsunderhåll genom att se över kostnader och intäkter i intressentkedjan mellan de primära kunderna och de som kan åtgärda problemen.Lyft fram goda exempel (best practice) på väl fungerande fordonsunderhåll.Låt universitet och högskolor få en viktig och neutral roll i den kunskapsbaserade utvecklingen.Detta bör ske genom att skapa ett forsknings- utvecklings- och demonstrations (FUD)-program inom området underhåll för järnvägsfordon. I denna färdplan föreslås även ett antal olika forskningsprojekt och -områden som skulle kunna utvecklas i ett sammanhållet forskningsprogram.
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| 8. |
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| 9. |
- Hassellöv, Ida-Maja, 1974, et al.
(författare)
-
Miljörisker sjunkna vrak II. Undersökningsmetoder och miljöaspekter
- 2015
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- During 2015 the Swedish Maritime Administration continued the second phase of thegovernmental task Environmental risks from sunken wrecks which first report was finalized2014-10-31 (Dnr: 1399-14-01942-6).The main conclusions from the 2014 report remain; for future handling of potentially pollutingshipwrecks it is recommended that the Swedish Agency for Water and Marine Management isgiven a coordinating responsibility in close cooperation with other competent nationalauthorities, such as Swedish Maritime Administration, Swedish Coastguard, Swedish NationalMaritime Museums, the Geological Survey of Sweden, SMHI, Swedish EPA, and SwedishCivil Contingencies Agency. Through coordination of wreck related operations and activitieswithin the concerned competent authorities’ ordinary areas of responsibility, resourceefficiency is improved. The estimated extra cost for implementation of a national strategy forhandling of the wrecks are estimated to be 10-15 MSEK which should be allocated to thecompetent authorities by the Swedish Agency for Water and Marine Management.The conclusions from 2014 was reinforced during 2015, e.g. through the validation of the riskassessment model VRAKA, which is now available in a first operative version. Additionalecotoxicological experiments on the development of tolerance against PAHs in meiofauna andmicroorganism communities were conducted in a field study in Brofjorden. The mainconclusions from this work is that comprehensive analyzes of PAHs should include alkylatedPAHs, and that exposure to PAHs over time can lead to tolerance development in ammoniumoxidizing bacteria, at the expense of their ability to perform the essential ecosystem servicenitrification.Continued measurements of the bottom currents were made at the wrecks Villon and Skytteren,and at the dumping area west of Måseskär. Measurement series yielded important informationon how measuring equipment at the wreck can be deployed in an optimized way in futuremonitoring program; to calculate the possible spreading of pollution from a wreck, currentmeasurements should be performed upstream from the wreck site, while sensors for thedetection of, for example, oil should be put into the turbulence downstream of the wreck.The current measurement instruments (RDCP) deployed at the Måseskär dump site was trawledup after only three weeks of measurements, but still gave valuable information on the extensivebottom trawling that resuspend (stir up) sediments. Earlier geochemical surveys have shownsignificantly elevated arsenic concentrations in the area and sediment resuspension greatlyincreased the risk for spread of any contaminants in the area. Trawling is not prohibited in thearea, and the current lack of knowledge regarding potential effects on human health whenconsuming seafood from dump areas calls for reflection upon the suitability of trawling in thearea.In addition to the current measurements Swedish Maritime Administration and the SwedishNavy conducted hydrographic survey with multibeam and side scan sonar and ROVinvestigation of the wrecks in the dumping area at Måseskär. 28 wrecks were found, and ROVinvestigation showed cargo holds with dumped torpedoes or mines and other containers in some SjöfartsverketDnr: 1399-14-01942-156of the wrecks. There is some discrepancy between the previously measured elevated arsenicconcentrations in the Måseskär area and recently presented data from historical archives thatdoes not support the theory that chemical weapons were dumped in the area. However, there isa very good correlation between the dominant current direction in the area, and the highestmeasured arsenic concentrations in the area downstream of the wrecks, suggesting some formof arsenic source in the area.
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| 10. |
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| 11. |
- Weng, Jianping, et al.
(författare)
-
Screening for MODY mutations, GAD antibodies, and type 1 diabetes--associated HLA genotypes in women with gestational diabetes mellitus.
- 2002
-
Ingår i: Diabetes Care. - : American Diabetes Association. - 1935-5548 .- 0149-5992. ; 25:1, s. 68-71
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To investigate whether genetic susceptibility to type 1 diabetes or maturity-onset diabetes of the young (MODY) increases susceptibility to gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS: We studied mutations in MODY1-4 genes, the presence of GAD antibodies, and HLA DQB1 risk genotypes in 66 Swedish women with GDM and a family history of diabetes. An oral glucose tolerance test was repeated in 46 women at 1 year postpartum. RESULTS: There was no increase in type 1 diabetes-associated HLA-DQB1 alleles or GAD antibodies when compared with a group of type 2 diabetic patients (n = 82) or healthy control subjects (n = 86). Mutations in known MODY genes were identified in 3 of the 66 subjects (1 MODY2, 1 MODY3, and 1 MODY4). Of the 46 GDM subjects, 2 had diabetes (4%) and 17 had impaired glucose tolerance (IGT) (37%) at 1 year postpartum. Of the two subjects who developed manifest diabetes, one carried a MODY3 mutation (A203H in the hepatocyte nuclear factor-1alpha gene). There was no increase in high-risk HLA alleles or GAD antibodies in the women who had manifest diabetes or IGT at 1 year postpartum. CONCLUSIONS: MODY mutations but not autoimmunity contribute to GDM in Swedish women with a family history of diabetes and increase the risk of subsequent diabetes.
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| 12. |
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| 13. |
- Achtenhagen, Leona, et al.
(författare)
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Fostering growth through business development : Core activities and challenges for micro-firm entrepreneurs
- 2017
-
Ingår i: Journal of Management and Organization. - : Cambridge University Press. - 1833-3672 .- 1839-3527. ; 23:2, s. 167-185
-
Tidskriftsartikel (refereegranskat)abstract
- As a concept stemming from practice, business development has received scarce academic attention. In this paper, we explore core business development activities of micro-firms and the challenges they perceive in conducting them. Based on interviews with 30 micro-firms, we identify three core business development activities that leverage the firm's resource base, complemented by three support activities that secure and organize the firm's resources. We find the business development activities to be tightly related to the three practices of leveraging, securing and organizing resources. We also identify three important contextual influences on business development in micro-firms: industry, age and if the firm is in an incubator. Our findings contribute to developing a conceptualization and theorization of business development for micro-firms, which is relevant as the vast majority of companies worldwide are micro-firms, but many never embark on a growth path. Based on our results, we outline practical implications, for example, how companies could overcome their perceived lack of time and an agenda for future research encouraging further studies comprising micro-firms with different qualities.
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| 14. |
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| 15. |
- Aggestam, Emil, 1992, et al.
(författare)
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Innovative requirements and evaluation methods for slab track design
- 2024
-
Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - 0954-4097 .- 2041-3017. ; 238:6, s. 651-661
-
Tidskriftsartikel (refereegranskat)abstract
- With increasing train speeds and reduced time windows for maintenance work, the interest in the application of slab track technology to increase the capacity of high-speed railways has grown. Slab track may still be considered a relatively young technology, but with several different designs available on the market. Current research on slab tracks commonly focuses on improved methods. In contrast, the formulation of requirements, and evaluation towards these, are seldom investigated. In this paper, state-of-the-art simulation models are employed to illustrate and address the needs for innovative requirements in terms of structural integrity and robustness, life cycle cost (LCC) and environmental footprint of new and existing slab track designs. Based on demonstration examples, it is argued that current standards may lead to overly conservative designs inducing higher LCC and environmental footprint than necessary. Extensions of the standards in terms of LCC and environmental footprint are suggested. The conflict of interest between structural integrity and robustness, LCC and environmental footprint is discussed, and suggestions for how to optimise slab track structures are proposed.
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| 16. |
- Aggestam, Emil, 1992, et al.
(författare)
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Optimisation of slab track design considering dynamic train–track interaction and environmental impact
- 2022
-
Ingår i: Engineering Structures. - : Elsevier BV. - 1873-7323 .- 0141-0296. ; 254
-
Tidskriftsartikel (refereegranskat)abstract
- Modern railway tracks for high-speed traffic are often built based on a slab track design. A major disadvantage of slab track compared to conventional ballasted track is that the environmental impact of the construction is higher due to the significant amount of concrete required. In this paper, the dimensions of the rectangular cross-sections and the types of concrete used in slab tracks are optimised with the objective to minimise greenhouse gas emissions, while considering the constraint that the design must pass the static dimensioning analysis described in the European standard 16432-2. The optimised track design is also analysed using a three-dimensional (3D) model of vertical dynamic vehicle–track interaction, where the rails are modelled as Rayleigh–Timoshenko beams and the concrete parts are represented by quadratic shell elements. Wheel–rail contact forces and the time-variant stress field of the concrete parts are calculated using a complex-valued modal superposition for the finite element model of the track. For the studied traffic scenario, it is concluded that the thickness of the panel can be reduced compared to the optimised design from the standard without the risk of crack initiation due to the dynamic vehicle load. In parallel, a model of reinforced concrete is developed to predict crack widths, the bending stiffness of a cracked panel section and to assess in which situations the amount of steel reinforcement can be reduced. To reduce the environmental impact even further, there is potential for an extended geometry optimisation by excluding much of the concrete between the rails.
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| 17. |
- Ahlström, Johan, 1969, et al.
(författare)
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Temperature-dependent evolution of the cyclic yield stress of railway wheel steels
- 2016
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Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 366:SI, s. 378-382
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Tidskriftsartikel (refereegranskat)abstract
- The evolution of the cyclic yield stress for a railway wheel steel (UIC ER7T) during cyclic plastic straining has been characterized at different temperatures from -60 to 600 °C. Different constant strain amplitude levels were examined and for temperatures above 200 °C, hold periods were included to study stress relaxation during constant compressive strain. The results are of use in predicting material deformation and damage. This is demonstrated by the application to improve a criterion for surface initiated rolling contact fatigue damage.
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| 18. |
- Ahlström, Johan, 1969, et al.
(författare)
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Temperature-dependent evolution of the cyclic yield stress of railway wheel steels
- 2015
-
Ingår i: Proceedings of the 10th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems (CM2015).
-
Konferensbidrag (refereegranskat)abstract
- The evolution of the cyclic yield stress for a railway wheel steel (UIC ER7T) during cyclic plastic straining has been characterized at different temperatures from -60 – 600°C. Two strain amplitude levels were examined and for temperatures above 200°C, hold periods were included to study stress relaxation during constant compressive strain. The results are of use in predicting material deformation and damage. This is demonstrated by the application to improve a criterion for surface initiated rolling contact fatigue damage.
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| 19. |
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| 20. |
- Andelid, Kristina, 1953, et al.
(författare)
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Myeloperoxidase as a marker of increasing systemic inflammation in smokers without severe airway symptoms
- 2007
-
Ingår i: Respiratory medicine. - : Elsevier BV. - 0954-6111. ; 101:5, s. 888-95
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: There is increasing evidence of systemic inflammation in patients with chronic obstructive pulmonary disease (COPD), but there is very little information on the development of systemic inflammation in smokers without severe airway symptoms. In this longitudinal study, we examined whether smokers with mild or no airway symptoms develop signs of systemic inflammation by assessing inflammatory markers in blood over a 6-year period. METHODS: Forty smokers and 28 male never-smokers were investigated in 1995 (year 0) and 6 years later (year 6). At year 6, 11 smokers had stopped smoking (quitters); these subjects were analysed as a separate group. At year 0 and 6, we measured serum levels of myeloperoxidase (MPO), lysozyme and human neutrophil lipocalin (HNL), regarded as markers of activity in neutrophils plus monocyte-lineage cells, monocyte-lineage cells only and neutrophils only. RESULTS: All systemic markers of inflammation (MPO, HNL and lysozyme) were significantly higher in smokers than in never smokers at year 6. For MPO alone, smokers only displayed a unique pattern compared with the other groups; the concentration of MPO in blood increased among smokers during the 6-year period, and this increase was statistically significant compared with that observed in never-smokers. Even though quitters did not display any clear change in MPO, we observed a statistically significant negative correlation between the change in blood MPO and the duration of smoking cessation in this group. For HNL and lysozyme, the changes over time were similar in smokers and never-smokers, with no statistically significant difference compared with quitters. CONCLUSION: This study provides evidence that male smokers without severe airway symptoms develop an increasing systemic inflammation during a 6-year period. The study forwards both direct and indirect evidence that MPO may be an early marker of this systemic inflammation. However, our study also forwards indirect evidence that ongoing tobacco smoking may "drive" the level of systemic HNL and lysozyme. The origin of the increased MPO and its value as an easily measured predictor for future COPD deserves to be further evaluated.
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| 21. |
- Andersson, Robin, 1986, et al.
(författare)
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Integrated analysis of dynamic vehicle-track interaction and plasticity induced damage in the presence of squat defects
- 2015
-
Ingår i: Proceedings of the 10th International International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, Colorado Springs, USA, August-September 2015.
-
Konferensbidrag (refereegranskat)abstract
- Despite significant efforts, the mechanisms behind the formation of squats – a form of rolling contact fatigue damage – are not fully understood. This study employs numerical simulations to investigate the propensity of squat initiation in the vicinity of small, isolated rail surface irregularities. Time domain dynamic vehicle–track interaction analysis is used to obtain wheel–rail contact stress distributions, which are mapped onto a continuum finite element model that accounts for plastic deformation of the rail material. The evaluated stress and strain fields are quantified using two RCF impact measures: accumulated effective strain and the Jiang-Sehitoglu multiaxial low cycle fatigue parameter. It is shown that the RCF impact increases with increasing size of the surface irregularity and that clustering of irregularities might strongly promote RCF. The friction coefficient is identified as a very influential parameter. Further, the effect of variations in friction along the rail is evaluated. It is shown that a short rail section of low friction results in fairly high RCF impact.
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| 22. |
- Andersson, Robin, 1986, et al.
(författare)
-
Integrated analysis of dynamic vehicle–track interaction and plasticity induced damage in the presence of squat defects
- 2016
-
Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 366-367:SI, s. 139-145
-
Tidskriftsartikel (refereegranskat)abstract
- Despite significant efforts, the mechanisms behind the formation of squats – a form of rolling contact fatigue (RCF) damage – are not fully understood. This study employs numerical simulations to investigate the propensity of squat initiation in the vicinity of small, isolated rail surface irregularities. Time-domain dynamic vehicle–track interaction analysis is used to obtain wheel–rail contact stress distributions, which are mapped onto a continuum finite element model that accounts for plastic deformation of the rail material. The evaluated stress and strain fields are quantified using two RCF impact measures: accumulated effective strain and the Jiang–Sehitoglu multiaxial low cycle fatigue parameter. It is shown that the RCF impact increases with increasing size of the surface irregularity and that clustering of irregularities might strongly promote RCF. The friction coefficient is identified as a very influential parameter and also the effect of variations in friction along the rail is evaluated.
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| 23. |
- Andersson, Robin, 1986, et al.
(författare)
-
Numerical assessment of the loading of rolling contact fatigue cracks close to rail surface irregularities
- 2020
-
Ingår i: Fatigue and Fracture of Engineering Materials and Structures. - : Wiley. - 8756-758X .- 1460-2695. ; 43:5, s. 947-954
-
Tidskriftsartikel (refereegranskat)abstract
- Rolling contact fatigue damage of railway rails in the form of squats, characterised by local depressions and cracks located at the rail surface, has been linked to the occurrence of local rail surface irregularities. This study concerns rolling contact fatigue cracks in the vicinity of fairly smooth surface irregularities, here denoted dimples. The influence of factors such as dimple geometry, cluster effects, and crack size is evaluated. To this end, dynamic vehicle–track simulations featuring realistic wheel and rail profiles are employed to characterise the dynamic impact during a wheel passage. The contact load in the vicinity of the dimples is then mapped onto a 3D finite element model of a rail section containing a crack in the rail head. The crack loading is finally quantified by multimodal stress intensity factors. The analyses establish that also shallow dimples might have a significant impact on the crack loading. This effect is increased for larger or multiple irregularities but decreases as the crack grows.
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| 24. |
- Andersson, Robin, 1986, et al.
(författare)
-
Numerical investigation of crack initiation in rails and wheels affected by martensite spots
- 2018
-
Ingår i: International Journal of Fatigue. - : Elsevier BV. - 0142-1123. ; 114, s. 238-251
-
Tidskriftsartikel (refereegranskat)abstract
- White etching layers (WELs) in the form of thermally induced martensite spots are often associated to so-called stud defects on rail surfaces and so-called rolling contact fatigue clusters on wheel treads. These defects might promote further material deterioration of rails and wheels and it is thus of importance to deepen the knowledge regarding their initiation mechanisms. The aim of this study is to gain insight into the problem by making qualitative assessments of different operational scenarios, involving various axle loads and amount of friction. To this end, this paper considers crack initiation, quantified through the Jiang–Sehitoglu low cycle fatigue criterion, in the vicinity of pre-existing WELs (in the form of martensite spots) subjected to varying contact load conditions. Three-dimensional finite element analyses are conducted to model phase transformations as well as the resulting residual stresses. It is seen that the contact pressure magnitude and WEL thickness affect the results only moderately, while the traction coefficient has a significant detrimental influence. It is furthermore seen that occasional wheel passages that are off-set in the lateral direction with respect to the WEL spot’s centre might be responsible for crack initiation on the gauge corner side of the rail surface.
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| 25. |
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| 26. |
- Arneson, Hanna, et al.
(författare)
-
Psychiological empowerment at the workplace and self-rated health and burnout : a 2-yeah longitudinal analysis in a sample of Swedish employees
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- PURPOSE: To explore the gender-specific longitudinal association between psychological empowerment at the workplace and self-rated health and burnout in a working population.MATERIAL AND METHOD: The participants were employees working in the public service sector in central Sweden. The baseline survey was carried out in 2001 and the follow-up in 2003. The questionnaire was answered by 715 respondents at both points in time (overall response rate 67%). Measures used were Psychological Empowerment Instrument by Spreitzer, the SF-36, the EQ-5D, and the Copenhagen Burnout Inventory. Gender specific differences in average score for self-rated health and burnout at follow-up were assessed using multiple linear regression adjusted for age, education, study cohort and self-rated health and burnout at baseline. An analysis on interactional effects due to gender was also performed.RESULTS: For women, increasing levels of psychological empowerment at work at baseline are associated with less bodily pain, better physical role function and mental health in the multivariate analysis at follow-up two years later. For men, increased psychological empowerment at baseline is significantly associated with better self-rated health as measured by the EQ-5D VAS at follow-up in the multivariatc analysis. Higher levels of psychological empowerment at baseline show a statistically significant association with a lower degree of burnout at follow-up in the univariate analysis for men and women. However, the associations diminished after adjustments in the multivariate analyses. No significant gender x empowerment interaction appeared.CONCLUSION: Psychological empowerment in working life was associated with somatic and mental aspects of SRH two years later for women. Men seem to be less affected by psychological empowerment, yet an association with the EQ-5D V AS appeared. Psychological empowerment did not predict burnout two years later for either men or women.
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| 27. |
- Arneson, Hanna, et al.
(författare)
-
Psychological empowerment and self-rated health and burnout in a sample of Swedish employees
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- PURPOSE: To explore the gender-specific association between psychological empowerment and self-rated health and burnout in a working population.MATERIAL AND METHOD: A cross-sectional survey was carried out among 1,243 employees (response rate 81% (n=1007), 65 % females). Psychological empowerment was measured by the Spreitzer questionnaire, developed for a working life context. The questionnaire includes the subscales: meaning, competence, self-determination and impact. Self-rated health was evaluated with EQ-5D and SF-36 and the Copenhagen Burnout Inventory was used to measure burnout.RESULTS: Men reported a greater degree of empowerment than women in terms of self-determination and impact. Significant associations (p<0.05) were found between psychological empowerment and self-rated health and burnout. Men and women with higher levels of empowerment reported significantly better health compared to those with lower levels of empowerment. In multivitriate analyses, all four subscales of empowerment were associated with burnout among both men and women. The most pronounced association with self-rated health was seen for the subscale impact. These associations were particularly strong among women.CONCLUSION: Psychological empowerment in working life is associated with self-rated health and burnout. Interventions aiming to promote health at work or aiming to prevent burnout may therefore benefit if they comprise empowerment in terms of impact, self-determination, meaning and competence. Also, workplace health promotion that includes empowerment processes should be gender conscious.
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| 28. |
- Arneson, Hanna, et al.
(författare)
-
Psychological empowerment, social support at the workplace and self-rated health and burnout : a 2-year longitudinal analysis in a sample of Swedish employees
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- PURPOSE: To explore the gender-specific longitudinal association between a combination of psychological empowerment and social support at the workplace and self-rated health and burnout in a working population.MATERIAL AND METHOD: The participants were employees working in the public service sector in central Sweden. The baseline survey in two cohorts was carried out in 2001 and the follow-up in 2003. The questionnaire was answered by 715 respondents at both points in time (overall response rate 67%). Measures used were the Psychological Empowerment Instrument by Spreitzer, the social support dimension in the Demand-Control-Support Questionnaire, the SF-36, the EQ-5D, and the Copenhagen Burnout Inventory. Based on empirical medians, psychological empowerment and social support at baseline were combined into four categories. Mlltivariate comparisons adjusted for age, education, study cohort and SRH and burnout at baseline were performed using multiple linear regression analysis. The genderxempowerment and social support interaction effect was assessed in the multiple linear regression analysis. All analyses were performed for men and women separately.RESULTS: For women, a combination of high psychological empowerment and high social support at the workplace, in comparison with a combination of low psychological empowerment and low social support, is strongly associated with better SRH (bodily pain, general health, vitality, social functioning, emotional role, mental health, the EQ-5D VAS, and EQ-5D index) and lower levels of work-related burnout at the 2-year follow-up after adjusting for demographics and baseline SRH and burnout. For men, there are univariate associations with burnout and some associations with SRH. After adjustments for demographics and baseline SRH and burnout, psychological empowerment and social support is associated with SRH as measured by the EQ-5D VAS for men. The gender x empowerment and social support interaction analyses confirm gender differences regarding bodily pain, social function, and work-related burnout.CONCLUSION: A combination of psychological empowerment and social support in working life strongly affects SRH and work-related burnout two years later for women, but only in part for men.
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| 29. |
- Arzola, Luis H., et al.
(författare)
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Viabahn-assisted sutureless anastomosis (VASA) repair of a complex internal carotid artery aneurysm
- 2023
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Ingår i: Journal of Vascular Surgery Cases and Innovative Techniques. - : Elsevier. - 2468-4287. ; 9:2
-
Tidskriftsartikel (refereegranskat)abstract
- Extracranial carotid artery aneurysms (CAAs) are extremely rare and often require surgical intervention to avoid complications such as local compression symptoms and thrombo-embolization. We present the case of a 63-year-old man with a history of hypertension, meningioma, and an incidental finding of a right saccular internal carotid artery aneurysm at the base of the skull. He underwent open surgical repair; nonetheless, end-to-end anastomosis was not feasible. As bailout, the internal carotid artery was successfully reconstructed with a novel Viabahn-assisted sutureless anastomosis technique (GORE, Viabahn). Postoperative clinical assessment revealed no complications, postoperative computed tomography angiography revealed a patent reconstruction, and the patient was discharged home uneventfully with 1-year clinical and computed tomography angiography follow-up without remarks. Hybrid procedure is a viable option for technically challenging carotid anastomoses near the skull base.
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| 30. |
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| 31. |
- Baumann, Pia, et al.
(författare)
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Outcome in a prospective phase II trial of medically inoperable stage I non-small-cell lung cancer patients treated with stereotactic body radiotherapy.
- 2009
-
Ingår i: Journal of clinical oncology : official journal of the American Society of Clinical Oncology. - 1527-7755 .- 0732-183X. ; 27:20, s. 3290-6
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The impact of stereotactic body radiotherapy (SBRT) on 3-year progression-free survival of medically inoperable patients with stage I non-small-cell lung cancer (NSCLC) was analyzed in a prospective phase II study. PATIENTS AND METHODS: Fifty-seven patients with T1NOMO (70%) and T2N0M0 (30%) were included between August 2003 and September 2005 at seven different centers in Sweden, Norway, and Denmark and observed up to 36 months. SBRT was delivered with 15 Gy times three at the 67% isodose of the planning target volume. RESULTS: Progression-free survival at 3 years was 52%. Overall- and cancer-specific survival at 1, 2, and 3 years was 86%, 65%, 60%, and 93%, 88%, 88%, respectively. There was no statistically significant difference in survival between patients with T1 or T2 tumors. At a median follow-up of 35 months (range, 4 to 47 months), 27 patients (47%) were deceased, seven as a result of lung cancer and 20 as a result of concurrent disease. Kaplan-Meier estimated local control at 3 years was 92%. Local relapse was observed in four patients (7%). Regional relapse was observed in three patients (5%). Nine patients (16%) developed distant metastases. The estimated risk of all failure (local, regional, or distant metastases) was increased in patients with T2 (41%) compared with those with T1 (18%) tumors (P = .027). CONCLUSION: With a 3-year local tumor control rate higher than 90% with limited toxicity, SBRT emerges as state-of-the-art treatment for medically inoperable stage I NSCLC and may even challenge surgery in operable instances.
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| 32. |
- Baumann, Pia, et al.
(författare)
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Stereotactic body radiotherapy for medically inoperable patients with stage I non-small cell lung cancer - a first report of toxicity related to COPD/CVD in a non-randomized prospective phase II study.
- 2008
-
Ingår i: Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. - : Elsevier BV. - 0167-8140 .- 1879-0887. ; 88:3, s. 359-67
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND AIMS: In a retrospective study using stereotactic body radiotherapy (SBRT) in medically inoperable patients with stage I NSCLC we previously reported a local control rate of 88% utilizing a median dose of 15Gyx3. This report records the toxicity encountered in a prospective phase II trial, and its relation to coexisting chronic obstructive pulmonary disease (COPD) and cardio vascular disease (CVD). MATERIAL AND METHODS: Sixty patients were entered in the study between August 2003 and September 2005. Fifty-seven patients (T1 65%, T2 35%) with a median age of 75 years (59-87 years) were evaluable. The baseline mean FEV1% was 64% and median Karnofsky index was 80. A total dose of 45Gy was delivered in three fractions at the 67% isodose of the PTV. Clinical, pulmonary and radiological evaluations were made at 6 weeks, 3, 6, 9, 12, 18, and 36 months post-SBRT. Toxicity was graded according to CTC v2.0 and performance status was graded according to the Karnofsky scale. RESULTS: At a median follow-up of 23 months, 2 patients had relapsed locally. No grade 4 or 5 toxicity was reported. Grade 3 toxicity was seen in 12 patients (21%). There was no significant decline of FEV1% during follow-up. Low grade pneumonitis developed to the same extent in the CVD 3/17 (18%) and COPD 7/40 (18%) groups. The incidence of fibrosis was 9/17 (53%) and pleural effusions was 8/17 (47%) in the CVD group compared with 13/40 (33%) and 5/40 (13%) in the COPD group. CONCLUSION: SBRT for stage I NSCLC patients who are medically inoperable because of COPD and CVD results in a favourable local control rate with a low incidence of grade 3 and no grade 4 or 5 toxicity.
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| 33. |
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| 34. |
- Bjarnason, Thordur, et al.
(författare)
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One-Year Follow-up After Open Abdomen Therapy With Vacuum-Assisted Wound Closure and Mesh-Mediated Fascial Traction
- 2013
-
Ingår i: World Journal of Surgery. - : Springer Science and Business Media LLC. - 0364-2313 .- 1432-2323. ; 37:9, s. 2031-2038
-
Tidskriftsartikel (refereegranskat)abstract
- Open abdomen (OA) therapy frequently results in a giant planned ventral hernia. Vacuum-assisted wound closure and mesh-mediated fascial traction (VAWCM) enables delayed primary fascial closure in most patients, even after prolonged OA treatment. Our aim was to study the incidence of hernia and abdominal wall discomfort 1 year after abdominal closure. A prospective multicenter cohort study of 111 patients undergoing OA/VAWCM was performed during 2006-2009. Surviving patients underwent clinical examination, computed tomography (CT), and chart review at 1 year. Incisional and parastomal hernias and abdominal wall symptoms were noted. The median age for the 70 surviving patients was 68 years, 77 % of whom were male. Indications for OA were visceral pathology (n = 40), vascular pathology (n = 22), or trauma (n = 8). Median length of OA therapy was 14 days. Among 64 survivors who had delayed primary fascial closure, 23 (36 %) had a clinically detectable hernia and another 19 (30 %) had hernias that were detected on CT (n = 18) or at laparotomy (n = 1). Symptomatic hernias were found in 14 (22 %), 7 of them underwent repair. The median hernia widths in symptomatic and asymptomatic patients were 7.3 and 4.8 cm, respectively (p = 0.031) with median areas of 81.0 and 42.9 cm(2), respectively (p = 0.025). Of 31 patients with a stoma, 18 (58 %) had a parastomal hernia. Parastomal hernia (odds ratio 8.9; 95 % confidence interval 1.2-68.8) was the only independent factor associated with an incisional hernia. Incisional hernia incidence 1 year after OA therapy with VAWCM was high. Most hernias were small and asymptomatic, unlike the giant planned ventral hernias of the past.
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| 35. |
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| 36. |
- Bruun, Laila, et al.
(författare)
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Rapid elimination by glomerular filtration of free prostate specific antigen and human kallikrein 2 after renal transplantation.
- 2004
-
Ingår i: Journal of Urology. - : Ovid Technologies (Wolters Kluwer Health). - 1527-3792 .- 0022-5347. ; 171:4, s. 1432-1435
-
Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The low molecular mass and short half-life of free (f) prostate specific antigen (PSA) implies elimination from blood by glomerular filtration. In addition, patients with terminal renal failure have increased fPSA in serum but there have been sparse data reported on the rates and pathways of elimination of PSA complexes and human kallikrein 2 (hK2). We studied glomerular filtration dependent elimination of fPSA and hK2 in patients with renal insufficiency undergoing successful renal transplantation.MATERIALS AND METHODS: We studied 14 patients with immediate onset of renal function after renal transplantation. Blood samples were obtained before and at regular intervals up to 160 hours after transplanted kidney reperfusion. Measurements of fPSA, total PSA and hK2 were performed with immunofluorometric assays and complexed PSA was determined by a chemiluminiscence assay. Glomerular filtration rates were monitored by analyzing serum creatinine and cystatin C. NONMEM, a multivariate pharmacokinetic approach, was used to determine the elimination rates of fPSA and hK2 after renal transplantation.RESULTS: Serum fPSA and hK2 but not PSA complexes, decreased rapidly after renal transplantation. Significant reductions in fPSA and hK2 were observed after only 16 and 8 hours, respectively. fPSA and hK2 showed similar elimination patterns, decreasing to 42% and 44% of their original levels compared to cystatin C, which was at 44% after 160 hours. The median half-lives of fPSA and hK2 were 17.4 and 11.5 hours, respectively.CONCLUSIONS: These results verify the hypothesis that fPSA and hK2 are eliminated from the blood circulation by glomerular filtration and severe renal failure influences the levels of the 2 proteins in serum.
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| 37. |
- Brännström, Mats, 1958, et al.
(författare)
-
Live birth after robotic-assisted live donor uterus transplantation.
- 2020
-
Ingår i: Acta obstetricia et gynecologica Scandinavica. - : Wiley. - 1600-0412 .- 0001-6349. ; 99:9, s. 1222-1229
-
Tidskriftsartikel (refereegranskat)abstract
- The proof-of-concept of uterus transplantation, as a treatment for absolute uterine factor infertility, came with the first live birth after uterus transplantation, which took place in Sweden in 2014. This was after a live donor procedure, with laparotomy in both donor and recipient. In our second, ongoing trial we introduced a robotic-assisted laparoscopic surgery of the donor to develop minimal invasive surgery for this procedure. Here, we report the surgery and pregnancy behind the first live birth from that trial.In the present study, within a prospective observational study, a 62-year-old mother was the uterus donor and her 33-year-old daughter with uterine absence as part of the Mayer-Rokitansky-Küster-Hauser syndrome, was the recipient. Donor surgery was mainly done by robotic-assisted laparoscopy, involving dissections of the utero-vaginal fossa, arteries and ureters. The last part of surgery was by laparotomy. Recipient laparotomy included vascular anastomoses to the external iliac vessels. Data relating to in vitro fertilization, surgery, follow up, obstetrics and postnatal growth are presented.Three in vitro fertilization cycles prior to transplantation gave 12 cryopreserved embryos. The surgical time of the donor in the robot was 360minutes, according to protocol. The durations for robotic surgery for dissections of the utero-vaginal fossa, arteries and ureters were 30, 160 and 84minutes, respectively. The remainder of donor surgery was by laparotomy. Recipient surgery included preparations of the vaginal vault, three end-to-side anastomoses (one arterial, two venous) on each side to the external iliacs and fixation of the uterus. Ten months after transplantation, one blastocyst was transferred and resulted in pregnancy, which proceeded uneventfully until elective cesarean section in week 36+1 . A healthy boy (Apgar 9-10-10) was delivered. Follow up of child has been uneventful for 12months.This is the first report of a live birth after use of robotic-assisted laparoscopy in uterus transplantation and is thereby a proof-of-concept of use of minimal invasive surgery in this new type of transplantation.
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| 38. |
- Brännström, Mats, 1958, et al.
(författare)
-
Livebirth after uterus transplantation.
- 2015
-
Ingår i: Lancet. - 1474-547X. ; 385:9968, s. 607-616
-
Tidskriftsartikel (refereegranskat)abstract
- Uterus transplantation is the first available treatment for absolute uterine infertility, which is caused by absence of the uterus or the presence of a non-functional uterus. Eleven human uterus transplantation attempts have been done worldwide but no livebirth has yet been reported.
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| 39. |
- Brännström, Mats, 1958, et al.
(författare)
-
One uterus bridging three generations: first live birth after mother-to-daughter uterus transplantation
- 2016
-
Ingår i: Fertility and Sterility. - : Elsevier BV. - 0015-0282 .- 1556-5653. ; 106:2, s. 261-266
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To determine whether a uterus from the mother of a woman with absolute uterine factor infertility can be transplanted to daughter and carry a pregnancy with delivery of a healthy child. Patient(s): Twenty eight-year-old woman with uterine agenesis, her male partner, and her 50-year-old mother. Intervention(s): In vitro fertilization with embryo cryopreservation before live donor uterus transplantation (UTx). Induction immunosuppression. Embryo transfer 12 months after UTx, pregnancy controls, delivery, and hysterectomy. Main Outcome Measure(s): Results of IVF-ET, parameters of pregnancy/birth, and surgical data of transplantation/cesarean section/hysterectomy. Result(s): Two IVF cycles before UTx resulted in 10 cryopreserved embryos. Donor surgery included hysterectomy with vascular pedicles of uterine vessels and proximal vessels up to and including parts of internal iliacs. Recipient surgery was by bilateral vascular connections to external iliacs, vaginal-vaginal anastomosis, and uterine fixation. Pregnancy occurred at the first single ET, and the pregnancy proceeded uneventfully until gestational week 34, when the patient developed cholestasis with intense pruritus. Cesarean section was performed at 34+6, with delivery of a healthy boy (weight 2,335 g). Hysterectomy was performed 3.5 months after delivery. The weight of the healthy child at 12 months was 9.3 kg. Grandmother (uterus donor) and mother are in good health 3 years after UTx. Conclusion(s): This is the first report of a live birth after mother-to-daughter UTx, and it also represents the second birth ever after human UTx. (C) 2016 by American Society for Reproductive Medicine.
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| 40. |
- Brännström, Mats, 1958, et al.
(författare)
-
Outcome of Recipient Surgery and 6-Month Follow-Up of the Swedish Live Donor Robotic Uterus Transplantation Trial.
- 2020
-
Ingår i: Journal of clinical medicine. - : MDPI AG. - 2077-0383. ; 9:8
-
Tidskriftsartikel (refereegranskat)abstract
- Uterus transplantation has proved to be a feasible treatment for uterine factor infertility. Herein, we report on recipient outcome in the robotic uterus transplantation trial of 2017-2019. The eight recipients had congenital uterine aplasia. The donors were six mothers, one sister, and one family friend. Donor surgery was by robotic-assisted laparoscopy. Recipient surgery was by laparotomy and vascular anastomoses to the external iliacs. The duration (median (ranges)) of recipient surgery, blood loss, measured (left/right) uterine artery blood flow after reperfusion, and length of hospital stay were 5.15 h (4.5-6.6), 300 mL (150-600), 43.5 mL/min (20-125)/37.5 mL/min (10-98), and 6 days (5-9), respectively. Postoperative uterine perfusion evaluated by color Doppler showed open anastomoses but restricted blood distribution in two cases. Repeated cervical biopsies in these two cases initially showed ischemia and, later, necrosis. Endometrial growth was not seen, and hysterectomy was later performed, with pathology showing partly viable myometrium and fibrosis but necrosis towards the cavity. The other six patients acquired regular menstrual cyclicity. Surgery was performed in two patients to correct vaginal stenosis. Reversible rejection episodes were seen in two patients. In conclusion, the rate of viable uterine grafts during the initial 6-months of the present study (75%) leaves room for improvement in the inclusion/exclusion criteria of donors and in surgical techniques. Initial low blood flow may indicate subsequent graft failure.
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| 41. |
- Caprioli, Sara, 1978, et al.
(författare)
-
Influence of short thermal cracks on the material behaviour of a railway wheel subjected to repeated rolling
- 2014
-
Ingår i: Advanced Materials Research. - 1662-8985 .- 1022-6680. - 9783038350088 ; 891-892, s. 1139-1145
-
Konferensbidrag (refereegranskat)abstract
- An analysis of whether and how the occurrence of shallow (radial) thermal cracks promotes additional plastic deformation of a mechanically loaded wheel tread is carried out. The study employs numerical simulations of a 2D slice of an elastoplastic railway wheel tread containing thermal (radial) cracks. The cracked wheel material is subjected to repeated passes of a frictional rolling contact load. The effect of the existing thermal cracks on bulk deformation and subsequent rolling contact promoted growth is quantified. Results indicate that thermal cracks of a depth of 0.1 mm have a negligible effect, whereas 1.0 mm cracks significantly decrease the bulk resistance of the wheel material. Further, it is shown how the magnitude of stress, strain and deformation depends on the direction of applied traction.
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| 42. |
- Caprioli, Sara, 1978, et al.
(författare)
-
Numerical evaluation of the material response of a railway wheel under thermomechanical braking conditions
- 2012
-
Ingår i: Proceedings of the 9th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems (CM2012). ; , s. 460-467
-
Konferensbidrag (refereegranskat)abstract
- The material response of a railway wheel subjected to thermomechanical rolling contact is evaluated. Thermal and mechanical loads are combined in a three-dimensional sequentially coupled analysis where nodal temper- atures from a transient thermal analysis are applied as predefined fields in a structural analysis featuring an elastic-plastic material model. The mechanical contact load is prescribed as a moving Hertzian contact stress distribution with a surface shear stress distribution corresponding to full or partial slip conditions. Modelling aspects studied in detail are feasible model resolution at the contact patch, the influence of sequences of thermal and mechanical loads, and the influence of wheel–rail interfacial shear distributions. The study identifies fea- sible mesh sizes and load application strategies to obtain a good accuracy at reasonable computational efforts. Further, differences in predicted material response under full slip and partial slip conditions are assessed. It is found that for a given total tangential force, partial slip conditions result in larger plastic strain magnitudes in a thin layer near the contact surface.
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| 43. |
- Caprioli, Sara, 1978, et al.
(författare)
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Numerical evaluation of the material response of a railway wheel under thermomechanical braking conditions
- 2014
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Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 314:1-2, s. 181-188
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Tidskriftsartikel (refereegranskat)abstract
- The material response of a railway wheel subjected to thermomechanical rolling contact is evaluated. Thermal and mechanical loads are combined in a three-dimensional sequentially coupled analysis where nodal temperatures from a transient thermal analysis are applied as predefined fields in a structural analysis featuring an elastic-plastic material model. The mechanical contact load is prescribed as a moving Hertzian contact stress distribution with a surface shear stress distribution corresponding to full or partial slip conditions. Modelling aspects studied in detail are feasible model resolution at the contact patch, the influence of sequences of thermal and mechanical loads, and the influence of wheel--rail interfacial shear distributions. The study identifies feasible mesh sizes and load application strategies to obtain a good accuracy at reasonable computational efforts. Further, differences in predicted material response under full slip and partial slip conditions are assessed. It is found that for a given total tangential force, partial slip conditions result in larger plastic strain magnitudes in a thin layer near the contact surface
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| 44. |
- Caprioli, Sara, 1978, et al.
(författare)
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Thermal Cracking of a Railway Wheel Tread due to Tread Braking – Critical Crack Sizes
- 2011
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Ingår i: Proceedings 2011 International Heavy Haul Association Conference. ; , s. 8-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A numerical study of tread cracking due to thermal loading induced by tread braking is carried out. The analysis features a computationally efficient approach combining 2D FE-simulations with an analytical evaluation of resulting stress intensity factors. The analysis identifies critical sizes for when existing surface cracks are prone to propagate under thermal loading and resulting crack lengths after propagation. The results imply that fully functional brake systems are not likely to induce thermal crack propagation under normal stop braking, but that with pre-existing defects a severe drag braking due to malfunctioning brakes may cause very deep cracking. Further the analysis concludes the cracking to be a static phenomenon related to the most severe brake cycle, i.e. later brake cycles of similar or lower severity will not cause any significant propagation of existing cracks. Preliminary 3D FE-simulations that have been performed indicate the presented results to be conservative.
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| 45. |
- Caprioli, Sara, 1978, et al.
(författare)
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Thermal cracking of a railway wheel tread due to tread braking -- critical crack sizes and influence of repeated thermal cycles
- 2013
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 227:1, s. 10-18
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Tidskriftsartikel (refereegranskat)abstract
- A numerical study of tread cracking due to thermal loading induced by tread braking is carried out. The analysis features a computationally efficient approach combining two-dimensional finite-element simulations with an analytical evaluation of resulting stress intensity factors. The analysis identifies critical sizes for when existing surface cracks are prone to propagate under thermal loading and resulting crack lengths after propagation. The results imply that fully functional brake systems are not likely to induce thermal crack propagation under normal stop braking, but that with pre-existing defects, a severe drag braking due to malfunctioning brakes may cause very deep cracking. Furthermore, the analysis concludes the cracking to be a static phenomenon related to the most severe brake cycle, i.e. later brake cycles of similar or lower severity will not cause any significant propagation of existing cracks. Additional three-dimensional finite-element simulations are used to validate the model, and they indicate two-dimensional results to be on the conservative side.
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| 46. |
- Caprioli, Sara, 1978, et al.
(författare)
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Thermal cracking of a railway wheel tread due to tread braking – critical crack sizes and influence of repeated thermal cycles
- 2011
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Ingår i: International Heavy Haul Association Special Technical Session (IHHA STS 2011). ; , s. 8-
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Konferensbidrag (refereegranskat)abstract
- A numerical study of tread cracking due to thermal loading induced by block braking is carried out. The analysis features a computationally efficient approach combining 2D FE-simulations with an analytical evaluation of resulting stress intensity factors. The analysis identifies critical sizes for when existing surface cracks are prone to propagate under thermal loading and resulting crack lengths after propagation. The results imply that fully functional brake systems are not likely to induce thermal crack propagation under normal stop braking, but that with pre-existing defects a severe drag braking due to malfunctioning brakes may cause very deep cracking. Further the analysis concludes the cracking to be a static phenomenon related to the most severe brake cycle, i.e. later brake cycles of similar or lower severity will not cause any significant propagation of existing cracks. Finally it should be noted that preliminary FE-simulations that have been performed indicate the presented results to be conservative.
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| 47. |
- Caprioli, Sara, 1978, et al.
(författare)
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THERMO-MECHANICAL CRACKING OF RAILWAY WHEEL
- 2011
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Ingår i: Proceedings for Svenska mekanikdagar 2011. ; , s. 1-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Thermo-mechanical wheel tread damages are common in railway wheels. While the damagemagnitude is limited this is a rather benign phenomenon. However under harsher operationalconditions (winter conditions, poorly tuned damping/suspension, poorly matched wheel–railcontact profiles etc) the extent of the problem may increase dramatically and lead to epidemicsof wheel damages. Since this calls for wheel re-profiling, the result may be extensiveoperational disturbances.The presentation deals with thermo-mechanical damage. In practice one of the failuremodes, thermal cracking or rolling contact fatigue, usually dominates. However, it is mostlikely that the combined thermal and rolling contact loading will have an influence in increasingthe resulting damage as compared to both phenomena acting separately.In the literature there are a multitude of studies on both thermal and rolling contactloading. analyses of the combined load case are however scarce. One major reason for this isthat a combined loading makes a simplification to 2D very cumbersome (not to say futile).Here, a numerical study of the impact of simultaneous thermal and mechanical loading on arailway wheel tread as imposed by braking and rolling contact is presented. 3D finite element(FE) simulations of the thermo-mechanical problem featuring a material model which accountsfor thermal expansion and plastic deformations are carried out. Both pure rolling and tractiverolling are considered. The results indicate a significant influence of the thermal loading onthe resulting stress/strain response also in cases of relatively moderate temperature increases.In particular, a combination of thermal loading and high traction rolling is found to be verydetrimental.The resulting damage of the wheel tread is manifested by the formation of small surfacecracks. In cases of high thermal loading, these cracks will evolve to deep radial cracks thatcan, in a worst-case scenario, cause catastrophic wheel failures. Since this is a potential safetyproblem it is important to understand the driving mechanisms behind these cracks.To this end, a numerical study of thermal cracking of a wheel subjected to high thermalloading was carried out. The analysis features a computationally efficient approach where2D FE stress analysis owing to thermal loading during braking and subsequent cooling iscombined with an analytical evaluation of resulting stress intensity factors of a radially orientedsurface crack in the wheel tread. The analysis identifies critical sizes for when existingsurface cracks are prone to propagate under thermal loading and resulting crack lengths afterpropagation. The results imply that fully functional brake systems are not likely to inducethermal crack propagation under normal stop braking, but that with pre-existing defects asevere drag braking due to malfunctioning brakes may cause very deep cracking. Further theanalysis concludes the thermal cracking to be a (more or less) static phenomenon related tothe most severe brake cycle. In other words: later brake cycles of similar or lower severitywill not cause any significant propagation of existing cracks. To further validate the analysisof the semi-analytical analysis, preliminary 3D FE-simulations have been performed.
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| 48. |
- Carlsson, Patrik, et al.
(författare)
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On an Implementation of a Distributed Passive Measurement Infrastructure
- 2003
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Having access to relevant, up-to-date measurement data is a key issue for network analysis in order to allow for efficient Internet performance monitoring and management. New applications keep appearing; user and protocol behavior keep evolving; traffic mixes and characteristics are continuously changing, which implies that some year old traffic traces may not reflect reality any more. In order to give a holistic view of what is going on in the network, passive measurements have to be carried out at different places simultaneously. Other challenges relate to the simultaneous use of one specific measurement point at a certain location for different measurement processes, and to continuously ongoing measurements needed for capturing long-term traffic behaviors. On this background, this paper proposes a passive measurement infrastructure for a campus backbone, consisting of distributed coordinated measurement points, collected in measurement areas, measurement administration and data management. … The framework is generic with regards to the capturing equipment, ranging from simple PCAP based devices to high-end DAG cards, and dedicated ASICs, in order to promote a large deployment of measurement points. This structure allows for an efficient use of passive monitoring equipment in order to supply researchers and network managers with up-to-date and relevant data.
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| 49. |
- Che, Karlhans Fru, et al.
(författare)
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The neutrophil-mobilizing cytokine interleukin-26 in the airways of long-term tobacco smokers
- 2018
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Ingår i: Clinical Science. - 0143-5221. ; 132:9, s. 959-983
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Tidskriftsartikel (refereegranskat)abstract
- Long-term tobacco smokers with chronic obstructive pulmonary disease (COPD) or chronic bronchitis display an excessive accumulation of neutrophils in the airways; an inflammation that responds poorly to established therapy. Thus, there is a need to identify new molecular targets for the development of effective therapy. Here, we hypothesized that the neutrophil-mobilizing cytokine interleukin (IL)-26 (IL-26) is involved in airway inflammation amongst long-term tobacco smokers with or without COPD, chronic bronchitis or colonization by pathogenic bacteria. By analyzing bronchoalveolar lavage (BAL), bronchail wash (BW) and induced sputum (IS) samples, we found increased extracellular IL-26 protein in the airways of long-term smokers in vivo without further increase amongst those with clinically stable COPD. In human alveolar macrophages (AM) in vitro, the exposure to water-soluble tobacco smoke components (WTC) enhanced IL-26 gene and protein. In this cell model, the same exposure increased gene expression of the IL-26 receptor complex (IL10R2 and IL20R1) and nuclear factor κ B (NF-κB); a proven regulator of IL-26 production. In the same cell model, recombinant human IL-26 in vitro caused a concentration-dependent increase in the gene expression of NF-κB and several pro-inflammatory cytokines. In the long-term smokers, we also observed that extracellular IL-26 protein in BAL samples correlates with measures of lung function, tobacco load, and several markers of neutrophil accumulation. Extracellular IL-26 was further increased in long-term smokers with exacerbations of COPD (IS samples), with chronic bronchitis (BAL samples ) or with colonization by pathogenic bacteria (IS and BW samples). Thus, IL-26 in the airways emerges as a promising target for improving the understanding of the pathogenic mechanisms behind several pulmonary morbidities in long-term tobacco smokers.
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| 50. |
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