| 1. |
- Bergh, Jonas, et al.
(författare)
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Tailored fluorouracil, epirubicin, and cyclophosphamide compared with marrow-supported high-dose chemotherapy as adjuvant treatment for high-risk breast cancer : A randomised trial
- 2000
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Ingår i: The Lancet. - 0140-6736 .- 1474-547X. ; 356:9239, s. 1384-1391
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Tidskriftsartikel (refereegranskat)abstract
- Background: Chemotherapy drug distribution varies greatly among individual patients. Therefore, we developed an individualised fluorouracil, epirubicin, cyclophosphamide (FEC) regimen to improve outcomes in patients with high-risk early breast cancer. We then did a randomised trial to compare this individually tailored FEC regimen with conventional adjuvant chemotherapy followed by consolidation with high-dose chemotherapy with stem-cell support. Methods: 525 women younger than 60 years of age with high-risk primary breast cancer were randomised after surgery to receive nine cycles of tailored FEC to haematological equitoxicity with granulocyte colony-stimulating factor (G-CSF) support (n=251), or three cycles of FEC at standard doses followed by high-dose chemotherapy with cyclophosphamide, thiotepa, and carboplatin (CTCb), and peripheral-blood stem-cell or bone-marrow support (n=274). Both groups received locoregional radiation therapy and tamoxifen for 5 years. The primary outcome measure was relapse-free survival, and analysis was by intention to treat. Findings: At a median follow-up of 34.3 months, there were 81 breast-cancer relapses in the tailored FEC group versus 113 in the CTCb group (double triangular method p=0.04). 60 deaths occurred in the tailored FEC group and 82 in the CTCb group (log-rank p=0.12). Patients in the CTCb group experienced more grade 3 or 4 acute toxicity compared with the tailored FEC group (p<0.0001). Two treatment-related deaths (0.7%) occurred in the CTCb group. Six patients in the tailored FEC group developed acute myeloid leukaemia and three developed myelodysplastic syndrome. Interpretation: Tailored FEC with G-CSF support resulted in a significantly improved relapse-free survival and fewer grade 3 and 4 toxicities compared with marrow-supported high-dose chemotherapy with CTCb as adjuvant therapy of women with high-risk primary breast cancer.
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| 2. |
- Ahmadpour, Doryaneh, 1973, et al.
(författare)
-
Robustness analysis of HOG pathway genes in Saccharomyces cerevisiae
- 2006
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Ingår i: YSBN Meeting Nov. 14-16, 2006- Vienna- Austria.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Robustness analysis of HOG pathway genes in Saccharomyces cerevisiae Doryaneh Ahmadpour1, Lars-Göran Ottosson1, Markus Krantz2, Jonas Warringer1, Anders Blomberg1 and Stefan Hohmann1* 1Department of Cell and Molecular Biology/Microbiology, Göteborg University, S-405 30 Göteborg, Sweden 2 The Systems Biology Institute (SBI), Shibuya, Tokyo, Japan E-mail: doryaneh.ahmadpour@gmm.gu.se Robustness is a fundamental property of biological systems and crucial for their effective function under internal or external perturbations. For instance, it has been proposed that internal parameters such as gene expression have been optimized during evolution such that a given system has the observed robustness. The permissible ranges of internal parameters in the cells are not comprehensively understood since there has not been a technique to measure such parameters. “Genetic tug-of-war” (gTOW) [1] is a genetic screening method that allows the investigation of the upper limit copy number of genes, and thereby the upper permissible range of gene expression level. This method is based on a 2-micron plasmid vector containing the leu2d allele with a very weak complementation activity and the gene of interest inserted as target gene. When the leu2ura3 deletion yeast cells transformed with pTOW plasmid are cultured under leucine-limiting conditions, there will be a bias toward increasing the plasmid copy number to compensate for the lack of leucine. On the other hand there will be an opposing bias toward decreasing the plasmid copy number if the target gene inhibits growth or has a toxic effect when a certain copy number is exceeded (it reaches to its upper limit). Eventually as a result of the “tug-of-war” between these two selection biases cells with optimized plasmid copy number will be concentrated. In this study we have applied the gTOW method on 29 HOG pathway related genes in Saccharomyces cerevisiae. The high osmolarity glycerol (HOG) MAPK pathway is essential for yeast survival in high osmolarity condition and consists of two branches that activate a MAPK (Hog1) via a MAPKK (Pbs2) to orchestrate part of the transcriptional response. The HOG pathway is the best understood osmoresponsive system in eukaryotes and the quantitative data provided by the gTOW method collating with the existing computational models could be used to analyze the robustness and fragility of the pathway. 1. Hisao Moriya, Yuki Shimizu-Yoshida and Hiroaki Kitano, 2006, PLoS Genetics, 2:7
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| 3. |
- Ahmadpour, Doryaneh, 1973, et al.
(författare)
-
Robustness analysis of HOG pathway related genes in Saccharomyces cerevisiae
- 2007
-
Ingår i: FEBS-SysBio March 10-16, 2007- Gosau, Austria.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Robustness analysis of HOG pathway related genes in Saccharomyces cerevisiae Doryaneh Ahmadpour1, Lars-Göran Ottosson1, Markus Krantz2, Jonas Warringer1, Anders Blomberg1 and Stefan Hohmann1* 1Department of Cell and Molecular Biology/Microbiology, Göteborg University, S-405 30 Göteborg, Sweden 2 The Systems Biology Institute (SBI), Shibuya, Tokyo, Japan E-mail: doryaneh.ahmadpour@gmm.gu.se Robustness is a fundamental property of biological systems and crucial for their effective function under internal or external perturbations. For instance, it has been proposed that internal parameters such as gene expression have been optimized during evolution such that a given system has the observed robustness. The permissible ranges of internal parameters in the cells are not comprehensively understood since there has not been a technique to measure such parameters. “Genetic tug-of-war” (gTOW) [1] is a genetic screening approach that allows the determination of the upper limit copy number of genes, and thereby the upper permissible range of the level of gene expression. This method is based on a 2-micron plasmid vector containing the LEU2d allele with a very weak complementation activity and the gene of interest inserted as target gene. When the leu2 ura3 mutant yeast transformed with pTOW plasmids is cultured under leucine-limiting conditions, there will be a bias toward increasing the plasmid copy number to satisfy the requirement for leucine. On the other hand there will be an opposing bias toward decreasing the plasmid copy number if the target gene inhibits growth when a certain copy number is exceeded (i.e. it reaches its upper limit). Eventually as a result of the “tug-of-war” between these two selection biases cells with optimized plasmid copy number will accumulate. In this study we have applied the gTOW method on 29 HOG pathway genes in S. cerevisiae. The high osmolarity glycerol (HOG) MAPK pathway is essential for yeast survival in high osmolarity condition [2]. It consists of two branches that activate a MAPK (Hog1) to orchestrate part of the transcriptional response. The HOG pathway is the best understood osmoresponsive system in eukaryotes. The quantitative data provided by the gTOW method collating with the existing computational models [3] could be used to analyze the robustness and fragility of the pathway. 1. Moriya H, et al., (2006), PLoS Genet 2(7): e111 2. Hohmann S (2002), Microbiol Mol Biol Rev 66:300 3. Klipp E, et al., (2005), Nat Biotechnol 23:975
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| 4. |
- Andersson, Dag, et al.
(författare)
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COSIVU - Compact, smart and reliable drive unit for fully electric vehicles
- 2016
-
Ingår i: 2016 Pan Pacific Microelectronics Symposium (Pan Pacific). - : Institute of Electrical and Electronics Engineers Inc.. - 9780988887398
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Konferensbidrag (refereegranskat)abstract
- COSIVU is a three year collaborative research project that ended in September 2015 and which has been funded within the European Green Car Initiative (now the European Green Vehicle Initiative). COSIVU addresses one of the most critical technical parts in fully electrical vehicles (FEV) besides the energy storage system: the mechatronic drive-train unit. The COSIVU project has delivered a new system architecture for multiple wheel drive-trains by a smart, compact and durable single-wheel drive unit with integrated electric motor, full silicon carbide (SiC) power electronics (switches and diodes), a novel control and health monitoring module with wireless communication, and an advanced ultra-compact cooling solution. DfR utilizing FEM simulations ensures first time right solutions. This paper presents the main results including the architecture of the drive train solution as well as the modular design of the inverter based on Inverter Building Blocks, one per phase. Performance tests are presented here for the first time for both the heavy duty commercial vehicle solution performed in a test rig by Volvo, and the tests of the COSIVU solution adapted to a passenger car done by Elaphe.
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| 5. |
- Barshep, Yahkat, et al.
(författare)
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Non-breeding ecology of the Whinchat Saxicola rubetra in Nigeria
- 2012
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Ingår i: Ornis Svecica. - 1102-6812 .- 2003-2633. ; 22, s. 25-32
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Tidskriftsartikel (refereegranskat)abstract
- This study on the non-breeding ecology of the Whinchat Saxicola rubetra was conducted in central Nigeria from February through April. The core site was at Gwafan (N09°53', E08°57'), an open scrubland located 10 km east of the city of Jos. The density of Whinchats at Gwafan was 0.58 individuals/ha, almost three times the overall density around Jos. Time budget observations of colour banded Whinchats, including six birds fitted with radio-transmitters, showed that they spent 80% of their time perching, 11% foraging, 7% preening, and 2% flying. The main method of catching insects was a swoop to the ground. There was no change in perching, preening or flying time but the time some Whinchats spent foraging increased towards the end of the study period. GPS positions of individuals showed that all birds held clearly demarcated territories and defended them against neighbours. Aggressive interactions were also recorded between Whinchats and other bird species. Three birds colour-ringed in 2006 returned to the study site in 2007 and one occupied almost the same territory, indicating site fidelity.
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| 6. |
- Behrenz, Lars, et al.
(författare)
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Arbetsgivares perspektiv på subventionerade anställningar : en kartläggning
- 2015
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Trots en kraftig ökning av antalet subventionerade anställningar från mitten av 2000-talet är det ett stort antal arbetsgivare som inte använder sig av lönesubventioner. Denna rapport har försökt att kartlägga och analysera arbetsgivares perspektiv på lönekostnadssubventioner. När det gäller analyser som berör de arbetsgivare som använt sig av lönesubventioner är den viktigaste förklaringsfaktorn att man använt sig av subventioner tidigare. Våra intervjuer visar också att de arbetsgivare som använder sig av lönesubventioner ofta har ett socialt ansvarstagande. Ett av huvudresultaten med följande studie är att 95 procent av de som använder sig av subventioner är nöjda. Omfattningen i pengar och personens kvalifikationer var mest avgörande för anställningsbeslutet. Av de som inte använt sig av lönesubventioner är det 20 procent som inte känt till att möjligheten finns. Intervjuer med arbetsgivare utan erfarenhet av att anställa med lönesubventioner visar att de är skeptiska att hitta lämplig personal genom att anställa med lönesubventioner. När vi ställer en hypotetisk fråga till samtliga arbetsgivare om vad som skulle kunna få dem att anställa med en subvention framkommer möjligheten att få pröva aktuell person som den klart viktigaste faktorn. Utifrån våra resultat föreslår vi bl.a. att Arbetsförmedlingen, i ett försöksupplägg, ska ges möjlighet att agera bemanningsföretag och vi föreslår också att man ska genomföra en omfattande informationskampanj till arbetsgivare.
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| 7. |
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| 8. |
- Brinkfeldt, Klas, et al.
(författare)
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Design and Fabrication of a SiC-Based Power Module with Double-Sided Cooling for Automotive Applications
- 2016
-
Ingår i: Lecture Notes in Mobility. - Cham : Springer International Publishing. - 2196-5544 .- 2196-5552. ; , s. 157-171, s. 157-172
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The electrification of drive trains combined with special requirements of the automotive and heavy construction equipment applications drives the development of small, highly integrated and reliable power inverters. To minimize the volume and increase the reliability of the power switching devices a module consisting of SiC devices with double sided cooling capability has been developed. There are several benefits related to cooling the power devices on both sides. The major improvement is the ability to increase the power density, and thereby reduce the number of active switching devices required which in turn reduces costs. Other expected benefits of more efficient cooling are reductions in volume and mass per power ratio. Alternatively, improved reliability margins due to lower temperature swings during operation are can be expected. Removing the wire bonds on the top side of the devices is expected to improve the reliability regardless, since wire bonds are known to be one of the main limitations in power switching devices. In addition, it is possible to design the package with substantially lower inductance, which can allow faster switching of the devices. In this paper the design, simulations and fabrication process of a double sided SiC-based power module are presented.
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| 9. |
- Brinkfeldt, Klas, et al.
(författare)
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Thermal Simulations and Experimental Verification of Power Modules Designed for Double Sided Cooling
- 2016
-
Ingår i: Electronic Components and Technology. - : Institute of Electrical and Electronics Engineers Inc.. - 0569-5503. ; , s. 1415-1422
-
Tidskriftsartikel (refereegranskat)abstract
- Cooling power modules on both sides of the active switching devices reduces the operational junction temperature compared to conventional single sided cooling. In this work, thermal simulations of power modules based on single sided cooling concepts are compared with double sided cooling counterparts. Expected junction temperatures, maximum temperatures and maximum current capability is analyzed. In addition, experimental verification in the form of comparisons with thermal characterization tests for both single-And double sided power modules based on SiC bipolar junction transistors is presented. Results from simulations show that cooling of both sides of the active switching devices can reduce the thermal resistance by more than 40 percent. This number depends on the heat transfer coefficient. From one example, simulating a worst case stall condition of the electric machine, the use of double sided cooling reduces the maximum junction temperature from 167 °C to 106 °C at a load current of 300 A using a heat transfer coefficient of 4 kW/m2K and 4 kHz switching frequency. Furthermore, the temperature decreases to 97°C if AlN-based DBC substrates are used instead of alumina DBCs. Results from the experimental comparison between double-And single sided cooling showed that the maximum temperature for a load current range of 15 A to 50 A was reduced by 18 percent to 55 percent by using double sided cooling. At a device temperature of 60 °C, the increased thermal capability of the double sided version allowed for a 20 A higher load current, which corresponded to operation under 50 percent higher power losses. Double sided cooling also increased the maximum current capability through a single SiC BJT by more than 20 percent beyond the maximum current capability through the single sided cooling version.
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| 10. |
- Brinkfeldt, Klas, et al.
(författare)
-
Thermo-Mechanical Simulations of SiC Power Modules with Single and Double Sided Cooling
- 2015
-
Ingår i: 16th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE), 2015. - : Institute of Electrical and Electronics Engineers Inc.. - 9781479999491 - 9781479999507 ; , s. 1 - 7
-
Konferensbidrag (refereegranskat)abstract
- Effectively removing dissipated heat from the switching devices enables a higher current carrying capability per chip area ratio, thus leading to smaller or fewer devices for a given power requirement specification. Further, the use of SiC based devices has proven to increase the efficiency of the system thereby reducing the dissipated heat. Thermal models have been used to compare SiC power modules. Single and double sided cooling have been simulated. The simulated maximum temperatures were 141 °C for the single sided version and 119.7 °C for the double sided version. In addition, the reliability of a single sided module and thermally induced plastic strains of a double sided module have been investigated. A local model of the wire bond interface to the transistor metallization shows a 30/00 maximum increase in plastic strain during the power cycle. Simulations of the creep strain rates in the die attach solder layer for a power cycling loads also shows a 30/00 increase in creep strain per cycle.
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| 11. |
- Bruze, Gustaf, et al.
(författare)
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Mental health from 5 years before to 10 years after bariatric surgery in adolescents with severe obesity: a Swedish nationwide cohort study with matched population controls
- 2024
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Ingår i: LANCET CHILD & ADOLESCENT HEALTH. - : ELSEVIER SCI LTD. - 2352-4642 .- 2352-4650. ; 8:2, s. 135-146
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Tidskriftsartikel (refereegranskat)abstract
- Background: The long-term effects of bariatric surgery on the mental health of adolescents with severe obesity remain uncertain. We aimed to describe the prevalence of psychiatric health-care visits and filled prescription psychiatric drugs among adolescents with severe obesity undergoing bariatric surgery in the 5 years preceding surgery and throughout the first 10 years after surgery, and to draw comparisons with matched adolescents in the general population. Methods: Adolescents with severe obesity and who underwent bariatric surgery were identified through the Scandinavian Obesity Surgery Registry. We included adolescents who had bariatric surgery between 2007 and 2017 and were younger than 21 years at time of surgery. Each adolescent patient was matched with ten adolescents from the general population by age, sex, and county of residence. Specialist psychiatric care and filled psychiatric prescriptions were retrieved from nationwide data registers. Findings: 1554 adolescents (<21 years) with severe obesity underwent bariatric surgery between 2007 and 2017, 1169 (75%) of whom were female. At time of surgery, the mean age was 19.0 years [SD 1.0], and the mean BMI was 43.7 kg/m(2) (SD 5.5). 15 540 adolescents from the general population were matched with adolescents in the surgery group. 5 years before the matched index date, 95 (6.2%) of 1535 surgery patients and 370 (2.5%) of 14 643 matched adolescents had a psychiatric health-care visit (prevalence difference 3.7%; 95% CI 2.4-4.9), whereas 127 (9.8%) of 1295 surgery patients and 445 (3.6%) of 12 211 matched adolescents filled a psychiatric drug prescription (prevalence difference 6.2%; 95% CI 4.5-7.8). The year before the matched index date, 208 (13.4%) of 1551 surgery patients and 844 (5.5%) of 15 308 matched adolescents had a psychiatric health-care visit (prevalence difference 7.9%; 95% CI 6.2-9.6), whereas 319 (20.6%) of 1551 surgery patients and 1306 (8.5%) of 15 308 matched adolescents filled a psychiatric drug prescription (prevalence difference 12.0%; 10.0-14.1). The prevalence difference in psychiatric health-care visits peaked 9 years after the matched index date (12.0%; 95% CI 9.0-14.9), when 119 (17.6%) of 675 surgery patients and 377 (5.7%) of 6669 matched adolescents had a psychiatric health-care visit. The prevalence difference in filled psychiatric drug prescription was highest 10 years after the matched index date (20.4%; 15.9-24.9), when 171 (36.5%) of 469 surgery patients and 739 (16.0%) of 4607 matched adolescents filled a psychiatric drug prescription. The year before the matched index date, 19 (1.2%) of 1551 surgery patients and 155 (1.0%) of 15304 matched adolescents had a health-care visit associated with a substance use disorder diagnosis (mean difference 0.2%, 95% CI -0.4 to 0.8). 10 years after the matched index date, the prevalence difference had increased to 4.3% (95% CI 2.3-6.4), when 24 (5.1%) of 467 surgery patients and 37 (0.8%) of 4582 matched adolescents had a health-care visit associated with a substance use disorder diagnosis. Interpretation: Psychiatric diagnoses and psychiatric drug prescriptions were more common among adolescents with severe obesity who would later undergo bariatric surgery than among matched adolescents from the general population. Both groups showed an increase in prevalence in psychiatric diagnoses and psychiatric drug prescriptions leading up to the time of surgery, but the rate of increase in the prevalence was higher among adolescents with severe obesity than among matched adolescents. With the exception of health-care visits for substance use disorders, these prevalence trajectories continued in the 10 years of follow-up. Realistic expectations regarding mental health outcomes should be set preoperatively. Funding: Swedish Research Council, Swedish Research Council for Health, Working Life and Welfare.
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| 12. |
- Claesson, Åsa, et al.
(författare)
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lntegrated Optical Fiber Sensors in Additive Manufactured Metal Components for Smart Manufacturing Applications
- 2019
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Ingår i: Smart Systems Integration; 13th International Conference and Exhibition on Integration Issues of Miniaturized Systems.
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Konferensbidrag (refereegranskat)abstract
- This work combines fiber optic sensors with additive manufacturing to enable integration of temperature and strain sensors in metal components. In this paper, we present a fiber optic sensor network integrated in press hardening tools to monitor the contact between the tool and the metal sheet during forming operation. The tools are manufactured through metal powder bed fusion using laser melting processes (PBF-SLM), after which the tools are prepared for sensor integration. A demonstrator press hardening tool with integrated fiber optic sensors was heated using an electric heat foil and the sensor measurements was compared to a thermal simulation model. The sensor technology is based on Fiber Bragg Gratings (FBGs), integrated at several positions along the optical fiber. FBGs are in-fiber sensors that are multiplexed. lt is possible to place hundreds of FBG sensors along one single fiber, thus allowing for quasidistributed sensing of temperature or strain. The optical fiber itself can be less than 100 micrometer in diameter, allowing for sensing at several points in a minimally invasive way, when integrated in a tool or component.
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| 13. |
- Gode, Jenny, et al.
(författare)
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Klimatbedömning av energilösningar i byggnader - Pilotprojekt för test av verktyget Tidstegen
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Verktyget Tidstegen kan användas för att analysera klimatpåverkan vid val av olika energiåtgärder. Resultaten från verktyget kan med fördel användas som ett komplement till andra beslutsunderlag (ekonomi och innemiljö med mera) när ett bygg- eller fastighetsföretag står inför beslut att genomföra en investering i nybyggnation eller i ändring av en befintlig byggnad. I rapporten beskrivs resultat från fyra olika pilotprojekt som har använt verktyget för att analysera klimatpåverkan av olika energiåtgärder i byggnader. Pilotprojekten har även bidragit till utvecklingen av verktyget genom regelbunden återkoppling. Pilotprojekten har genomförts i tre olika fjärrvärmenät (Linköping, Stockholm Nordvästra samt Stockholm Södra och Centrala). Ett av pilotprojekten har även inkluderat energilösningar med fjärrkyla och två pilotprojekt har omfattat solcellslösningar. Beräkningarna i verktyget Tidstegen bygger på så kallad konsekvensanalys, som innebär att effekterna av en förändrad energianvändning analyseras. Det är alltså bara de anläggningar i energisystemet (el, fjärrvärme, fjärrkyla) som påverkas av den förändrade energianvändningen som ingår i konsekvensanalysen. Verktygets beräkningar bygger på metodik som utvecklats av IVL i flera tidigare forskningsprojekt i samarbete med representanter från bygg-, fastighets- och energibranschen.
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| 14. |
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| 15. |
- Hellgren, Olof, et al.
(författare)
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Circannual variation in blood parasitism in a sub-Saharan migrant passerine bird, the garden warbler
- 2013
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Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 26:5, s. 1047-1059
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Tidskriftsartikel (refereegranskat)abstract
- Knowing the natural dynamics of pathogens in migratory birds is important, for example, to understand the factors that influence the transport of pathogens to and their transmission in new geographical areas, whereas the transmission of other pathogens might be restricted to a specific area. We studied haemosporidian blood parasites of the genera Plasmodium, Haemoproteus and Leucocytozoon in a migratory bird, the garden warbler Sylvia borin. Birds were sampled in spring, summer and early autumn at breeding grounds in Sweden, on migration at Capri, Italy and on arrival and departure from wintering staging areas in West Africa: mapping recoveries of garden warblers ringed in Fennoscandia and Capri showed that these sites are most probably on the migratory flyway of garden warblers breeding at Kvismaren. Overall, haemosporidian prevalence was 39%, involving 24 different parasite lineages. Prevalence varied significantly over the migratory cycle, with relatively high prevalence of blood parasites in the population on breeding grounds and at the onset of autumn migration, followed by marked declines in prevalence during migration both on spring and autumn passage. Importantly, we found that when examining circannual variation in the different lineages, significantly different prevalence profiles emerged both between and within genera. Our results suggest that differences in prevalence profiles are the result of either different parasite transmission strategies or coevolution between the host and the various parasite lineages. When separating parasites into common vs. rare lineages, we found that two peaks in the prevalence of rare parasites occur; on arrival at Swedish breeding grounds, and after the wintering period in Africa. Our results stress the importance of appropriate taxonomic resolution when examining host-parasite interactions, as variation in prevalence both between and within parasite genera can show markedly different patterns.
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| 16. |
- Hellgren, Olof, et al.
(författare)
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Detecting shifts of transmission areas in avian blood parasites - a phylogenetic approach
- 2007
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Ingår i: Molecular Ecology. - 0962-1083. ; 16:6, s. 1281-1290
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the degree of geographical shifts of transmission areas of vector-borne avian blood parasites (Plasmodium, Haemoproteus and Leucocytozoon) over ecological and evolutionary timescales. Of 259 different parasite lineages obtained from 5886 screened birds sampled in Europe and Africa, only two lineages were confirmed to have current transmission in resident bird species in both geographical areas. We used a phylogenetic approach to show that parasites belonging to the genera Haemoproteus and Leucocytozoon rarely change transmission area and that these parasites are restricted to one resident bird fauna over a long evolutionary time span and are not freely spread between the continents with the help of migratory birds. Lineages of the genus Plasmodium seem more freely spread between the continents. We suggest that such a reduced transmission barrier of Plasmodium parasites is caused by their higher tendency to infect migratory bird species, which might facilitate shifting of transmission area. Although vector-borne parasites of these genera apparently can shift between a tropical and a temperate transmission area and these areas are linked with an immense amount of annual bird migration, our data suggest that novel introductions of these parasites into resident bird faunas are rather rare evolutionary events.
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| 17. |
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| 18. |
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| 19. |
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| 20. |
- Holgersson, Ingemar, et al.
(författare)
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Fingu—A Game to Support Children’s Development of Arithmetic Competence: Theory, Design and Empirical Research
- 2016
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Ingår i: International Perspectives on Teaching and Learning Mathematics with Virtual Manipulatives. - : Springer. - 9783319327181 ; , s. 123-145
-
Bokkapitel (refereegranskat)abstract
- This chapter aims at describing research on Fingu, a virtual manipulative housed in a game environment, which is designed to support young children’s learning and development of number concepts and flexible arithmetic competence. More specifically Fingu targets the understanding and mastering of the basic numbers 1–10 as part-whole relations, which according to the literature on early mathematics learning is critical for this development. In the chapter, we provide an overview of the theoretical grounding of the design, development and research of Fingu as well as the theoretical and practical design rationale and principles. We point out the potential of Fingu as a research platform and present examples of some of the empirical research conducted to demonstrate the learning potential of Fingu. Methodologically, the research adopts a design-based research approach. This approach combines theory-driven design of learning environments with empirical research in educational settings, in a series of iterations. In a first series of iterations, a computer game—the Number Practice Game—was designed and researched, based on phenomenographic theory and empirical studies. In a second series of iterations, Fingu was designed and researched, based on ecological psychology in a socio-cultural framing. The design trajectory of NPG/Fingu thus involves both theoretical development and (re)design and development of specific educational technologies.
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| 21. |
- Jafri, Hassan M., et al.
(författare)
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Identification of vibrational signatures from short chains of interlinked molecule-nanoparticle junctions obtained by inelastic electron tunnelling spectroscopy
- 2013
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Ingår i: Nanoscale. - 2040-3364 .- 2040-3372. ; 5:11, s. 4673-4677
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Tidskriftsartikel (refereegranskat)abstract
- Short chains containing a series of metal- molecule-nanoparticle nanojunctions are a nano-materials system with the potential to give electrical signatures close to those from single molecule experiments while enabling to build portable devices on a chip. Inelastic electron tunnelling spectroscopy (IETS) measurements provide one of the most characteristic electrical signals of single and few molecules. In interlinked molecule-nanoparticle (NP) chains containing of typically 5-7 molecules in a chain, the spectrum is expected to be a superposition of the vibrational signature of individual molecules. We have established a stable and reproducible molecule-AuNP multi-junction by placing few 1,8-octanedithiol (ODT) molecules into a versatile and portable nanoparticle-nanoelectrode platform and measured for the first time vibrational molecular signatures complex and coupled few-molecule-NP junctions. From quantum transport calculations, we model the IETS spectra and identify vibrational modes as well as the number of molecules contributing to the electron transport in the measured spectra.
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| 22. |
- Jahn, Burkhard O., et al.
(författare)
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Organic Single Molecular Structures for Light Induced Spin-Pump Devices
- 2013
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 7:2, s. 1064-1071
-
Tidskriftsartikel (refereegranskat)abstract
- We present theoretical results on molecular structures for realistic spin-pump applications. Taking advantage of the electron spin resonance concept, we find that interesting candidates constitute triplet biradicals with two strongly spatially and energetically separated singly occupied molecular orbitals (SOMOs). Building on earlier reported stable biradicals, particularly bis(nitronyl nitroxide) based biradicals, we employ density functional theory to design a selection of potential molecular spin-pumps which should be persistent at ambient conditions. We estimate that our proposed molecular structures will operate as spin-pumps using harmonic magnetic fields in the MHz regime and optical fields in the infrared to visible light regime.
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| 23. |
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| 24. |
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| 25. |
- Johansson, Kari, et al.
(författare)
-
Risk of pre-eclampsia after gastric bypass : a matched cohort study
- 2022
-
Ingår i: British Journal of Obstetrics and Gynecology. - : Blackwell Publishing. - 1470-0328 .- 1471-0528. ; 129:3, s. 461-471
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To investigate whether gastric bypass before pregnancy is associated with reduced risk of preeclampsia.DESIGN: Nationwide matched cohort study.SETTING: Swedish national health care.POPULATION: =2766:2766) on pre-surgery/early-pregnancy BMI, diabetes status (pre-surgery/pre-conception), maternal age, early-pregnancy smoking status, educational level, height, country of birth, delivery year and history of preeclampsia.MAIN OUTCOME MEASURES: Preeclampsia categorised into any, preterm onset (<37+0 weeks), and term onset (≥37+0 weeks).RESULTS: (39kg). Post-gastric bypass pregnancies had lower risk of preeclampsia compared to pre-surgery BMI-matched controls (1.7 vs. 9.7 per 100 pregnancies; hazard ratio [HR] 0.21, 95%CI 0.15-0.28) and early-pregnancy BMI-matched controls (1.9 vs. 5.0 per 100 pregnancies; HR 0.44, 95%CI 0.33-0.60). Although relative risks for preeclampsia for post-gastric bypass pregnancies vs. pre-surgery matched controls was similar, absolute risk differences were significantly greater for nulliparous (RD -13.6 per 100 pregnancies, 95%CI -16.1 to -11.2) vs. parous women (RD -4.4 per 100 pregnancies, 95%CI -5.7 to -3.1).CONCLUSION: We found that gastric bypass was associated with lower risk of preeclampsia, with the largest absolute risk reduction among nulliparous women.
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| 26. |
- Krantz, Marcus, 1975, et al.
(författare)
-
Robustness and fragility in the high osmolarity glycerol (HOG) pathway in S. cerevisiae
- 2009
-
Ingår i: 10th International Conference on Systems Biology (ICSB2009) proceedings, 10th International Conference on Systems Biology (ICSB2009), Aug 30 - Sep 4, Stanford, California, USA.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Cellular signalling networks integrate environmental stimuli with information on cellular status. These networks must be robust against stochastic fluctuations in external stimuli as well as in the amounts of signalling components. Here [1], we challenge the yeast HOG signal transduction pathway with systematic perturbations in components’ expression levels implemented by a “genetic tug-of-war” methodology under various external conditions in search of nodes of fragilities. We observe a substantially higher frequency of fragile nodes in this signal transduction pathway than has been observed for other cellular processes. These fragilities disperse without any clear pattern over biochemical functions or location in pathway topology, with the most sensitive nodes being the proteins PBS2 and SSK1. They are also largely independent of pathway activation by external stimuli. However, the strongest toxicities are caused by pathway hyperactivation. We studied the influence of seven regulatory motifs around these HOG pathway components in silico through ODE models. Based on the SLN1 and the MAPK modules of a mathematical model of osmoregulation in budding yeast by Klipp et al. [2] we included new motifs and fitted the affected parameters to time courses of dually phosphorylated Hog1p generated by the original model under stress and stress-free conditions. The regulations taken into account by our analysis include Pbs2p scaffolding, Ssk1p and Pbs2p autoactivation, and the formation of a stable dimer between Ssk2p and Ssk1p. A subsequent sensitivity analysis identified Pbs2's role as a scaffold protein and Ssk1p-Ssk2p dimerization as the important contributors to the observed robustness pattern in silico. Thus, in vivo robustness data can be used to discriminate and improve mathematical models.
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| 27. |
- Krantz, Marcus, 1975, et al.
(författare)
-
Robustness and fragility in the yeast high osmolarity glycerol (HOG) signal-transduction pathway.
- 2009
-
Ingår i: Molecular systems biology. - : EMBO. - 1744-4292. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Cellular signalling networks integrate environmental stimuli with the information on cellular status. These networks must be robust against stochastic fluctuations in stimuli as well as in the amounts of signalling components. Here, we challenge the yeast HOG signal-transduction pathway with systematic perturbations in components' expression levels under various external conditions in search for nodes of fragility. We observe a substantially higher frequency of fragile nodes in this signal-transduction pathway than that has been observed for other cellular processes. These fragilities disperse without any clear pattern over biochemical functions or location in pathway topology and they are largely independent of pathway activation by external stimuli. However, the strongest toxicities are caused by pathway hyperactivation. In silico analysis highlights the impact of model structure on in silico robustness, and suggests complex formation and scaffolding as important contributors to the observed fragility patterns. Thus, in vivo robustness data can be used to discriminate and improve mathematical models.
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| 28. |
- Krantz, Marcus, 1975, et al.
(författare)
-
Robustness and fragility in the yeast High Osmolarity signal transduction pathway
- 2008
-
Ingår i: 2008 Yeast Genetics and Molecular Biology Meeting Program and Abstract Book, 2008 Yeast Genetics and Molecular Biology Meeting, July 22-27, 2008.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The cellular signalling networks that integrate various environmental stimuli with information on cellular status must be robust to stimuli fluctuations as well as to stochastic differences in the amounts of signalling components. Here, we challenge the Hog signal transduction pathway with systematic disturbances in components’ expression levels implemented by a “genetic tug-of-war”, or gToW, methodology. The disturbances were performed under various external perturbations, including pathway activation by osmotic shock. Ideally, the obtained sensitivity profiles will allow us to impose parameter constraints. However, a more important aspect is the qualitative improvement of model structures, when local fragilities cannot be explained by the model structure. The resulting phenotypes in this particular study reflect a wide range of sensitivities, and disperse without any clear pattern over biochemical functions and pathway modules alike, with the most sensitive nodes being PBS2 and SSK1. Surprisingly, the “neighbouring” nodes HOG1 and SSK2 were affected to a much lesser extent, questioning our current understanding.
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| 29. |
- Krantz, Marcus, 1975, et al.
(författare)
-
Robustness and fragility in the yeast High Osmolarity signal transduction pathway
- 2008
-
Ingår i: 9th International Conference on Systems Biology (ICSB2008) proceedings, 9th International Conference on Systems Biology (ICSB2008), August 22-28, Gothenburg.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Objective: The cellular signalling networks that integrate various environmental stimuli with information on cellular status must be robust to stimuli fluctuations as well as to stochastic differences in the amounts of signalling components. Here, we challenge the high osmolarity glycerol response (HOG) signal transduction pathway in the yeast Saccharomyces cerevisiae with systematic disturbances in components’ expression levels implemented by a “genetic tug-of-war”, or gTOW, methodology. Results: The disturbances were performed under various external perturbations, including pathway activation by osmotic shock. The resulting phenotypes in this particular study reflect a wide range of sensitivities, and disperse without any clear pattern over biochemical functions and pathway modules alike, with the most sensitive nodes being PBS2 and SSK1. Conclusions: Ideally, the obtained sensitivity profiles will allow us to impose parameter constraints. However, a more important aspect is the qualitative improvement of model structures, when local fragilities cannot be explained by the model structure. Surprisingly, the “neighboring” nodes HOG1 and SSK2 were affected to a much lesser extent, questioning our current understanding.
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| 30. |
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| 31. |
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| 32. |
- Lygnerud, Kristina, 1976-, et al.
(författare)
-
Business models combining heat pumps and district heating in buildings generate cost and emission savings
- 2021
-
Ingår i: Energy. - London : Elsevier. - 0360-5442 .- 1873-6785. ; 234
-
Tidskriftsartikel (refereegranskat)abstract
- The Author(s)There are currently several challenges facing the Swedish district heating (DH) industry. To address these challenges, new business models are needed. One such model involves the widespread use of Heat Pumps (HPs) in DH networks (DHN). However, HPs compete with other more conventional heat sources and their inclusion in DH business models is not yet common. In this study, efficiency gains impacting cost and CO2 emissions for HP inclusions are compared to the current state of affairs and different business model concepts are developed and discussed for a typology of DH systems. The results of this analysis show that using HPs in DHNs can be profitable, achieving maximum cost savings of 33% and emissions savings of 75% (CO2). However, the shift needed in business models for successful HP/DH combination—in spite of significant cost and emission savings potential—will be a significant challenge, considering: (i) the tendency of Swedish DH companies to see HPs as competition and something to avoid, (ii) an overall low level of maturity in terms of service provision, (iii) an arms-length distance to customers (co-creation of value is rare), and (iv) a difficulty in capitalising the value of green technology adoption. © 2021
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| 33. |
- Lygnerud, Kristina, et al.
(författare)
-
Skador och deras förebyggande i svenska fjärrvärmenät - Slutrapport av delprojekt inom GrönBostad Stockholm
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report is written as a part of the Grön BoStad project, financed by the European Regional Development Fund. The work reported here was performed by IVL Swedish Environmental Research Institute. Damages in the distribution networks for district heating and cooling drives costs for utility companies. Being able to prevent damages and leakages in the distribution networks should therefore be of interest for utility companies. In addition to preventing damages, it is also important to be able to quickly and efficiently detect damages in the network whenever they occur. Many of the pipes and lines in distribution networks were installed many years ago, when digital surveillance systems were not available to the same extent as they are today. The use of damage detection systems is widely spread in Swedish distribution networks, but there is no summarized and general information in how they are used and how efficient they are. This report has the purpose to investigate how district heating and cooling companies and property owners are working in order to prevent damages in district heating distribution networks and to quantify the value that this work creates. The investigation has been made through a literature review, collection and analysis of statistical data regarding damages in district heating networks and through interviews held with stakeholders in the industry. In order to place the study in an international context, some European distribution networks have also been included. Swedish district heating and cooling companies are in general well aware of the advantages that can be achieved by having a systematic approach to the prevention of damages in the distribution networks, there is however a lack of standardized and industry-common methods for this. Statistics concerning damages in Swedish district heating networks has not been gathered on a national level since some years and it is therefore hard to get a general picture of the status of the networks. The trade organization Energiföretagen is at the time of writing this report working actively with organizing national statistical data and improving the knowledge regarding damages in Swedish district heating networks. The use of damage detection methods varies between the district heating networks that have been studied in this report. The statistics from two Swedish district heating networks shows that 10 to 20 per cent of reported damages have been detected through automated systems. A large part of the damages is being detected by various, less direct, methods such as schedules inspections, thermography and through additional water being injected to the network because of leakages.
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| 34. |
- Mata, Erika, et al.
(författare)
-
A review of flexibility of residential electricity demand as climate solution in four EU countries
- 2020
-
Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326.
-
Tidskriftsartikel (refereegranskat)abstract
- Increased flexibility at the grid edge is required to achieve ambitious climate goals and can be provided by smart energy solutions. By systematically reviewing the literature, we provide an overview of the potential flexibility of different residential electrical loads for France, Germany, Sweden, and the United Kingdom. While 85% of the studies aimed to identify potentials for shifting electrical energy use in time, the other 15% aimed to identify energy-saving potentials. Most of the data were found for the German and British electrical systems. A wide range of flexibility measures (e.g., price mechanisms, user-centered control strategies for space heating and water heating, automated shifting of appliances' use, EV charging algorithms, and consumer feedback) and methods (e.g., simulations, trials, and interviews) have been used. Potentials obtained from the literature have been upscaled to the national level, including corresponding effects in terms of carbon dioxide (CO2) emissions. The results show that between 2% and 18% of residential sector electricity in the four countries could be shifted, resulting in total emission reductions of 10 MtCO2 from peak shaving, or 24 MtCO2 per year if optimizing the deployment of renewables. The literature identifies substantial economic, technical, and behavioral benefits from implementing flexibility measures. In all the cases, it seems that the current regulatory framework would need to change to facilitate participation. Recognized risks include higher peaks and congestions in low price-hours and difficulties in designing electricity tariffs because of conflicts with CO2 intensity as well as potential instability in the entire electricity system caused by tariffs coupling to wholesale electricity pricing.
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| 35. |
- Mata, Erika, et al.
(författare)
-
Solid state breakers as climate solutions
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Ökad flexibilitet i elnätets utkant är nödvändigt för att uppnå ambitiöst satta klimatmål. En sådan ökad flexibilitet kan fås genom smarta energilösningar. Dessa lösningar förväntas vara en del av det pågående skiftet inom energiförsörjningen, med ett större fokus på förnybar energi, både centralt och distribuerat i näten. Detta kombineras med att konsumenter får möjlighet att minska sina energikostnader genom att flytta sin elförbrukning i tiden, får bättre information kring och lösningar för att automatisera sin energiförbrukning och kan ta steget mot att bli prosumenter. Genom en systematisk genomgång av vetenskaplig litteratur ges en överblick av den potentiella flexibilitet som finns hos olika el-laster i bostadssektorn i Frankrike, Tyskland, Storbritannien och Sverige. Uppgifterna har hämtats från litteratur och skalats upp homogent för att spegla den nationella potentialen, inklusive effekten som den potentiella flexibiliteten har på koldioxidutsläppen. Våra resultat visar att mellan 2% och 18% av elanvändningen i bostadssektorn i de fyra EU-länderna kan flyttas i tiden, vilket skulle resultera i att utsläpp på mellan 10 och 28 Mton CO2 per år kan undvikas till förmån för att maximera användandet av förnybara energikällor. Med dagens prismekanismer och tariffer för energianvändning är flexibilitet av denna typ inte ekonomiskt hållbar och därför krävs förändringar.
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| 36. |
- Moberg, Christina, et al.
(författare)
-
De unga gör helt rätt när de stämmer staten
- 2022
-
Ingår i: Aftonbladet. - 1103-9000.
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 37. |
- Månsson, Jonas, et al.
(författare)
-
Deltidsarbete och deltidsarbetslöshet
- 2008
-
Ingår i: Välfärd på deltid. - Stockholm : SNS förlag. - 9789185695485 ; , s. 63-97
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 38. |
|
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| 39. |
- Månsson, Jonas, 1964-, et al.
(författare)
-
Transitions from part-time unemployment: Is part-time job a dead end or a stepping stone?
- 2011
-
Ingår i: Economic and Industrial Democracy. - 0143-831X .- 1461-7099. ; 32:4, s. 569-589
-
Tidskriftsartikel (refereegranskat)abstract
- This article analyses the effects of individual characteristics on the probability of leaving part-time unemployment. The results show that it cannot be unreservedly asserted that part-time work offers access to the core labour market. Among the part-time unemployed, there are great variations in the degree to which they are likely to leave part-time unemployment. A concentration of labour market policy activities on the part-time unemployed who are least likely to succeed in finding full-time employment can, therefore, be expected to have positive consequences from both equity and efficiency points of view. In this respect, part-time unemployed women, persons with work-related disabilities and persons with temporary employment come to the forefront. The article shows that the likelihood of finding a full-time job is certainly not great for persons belonging to these groups. For many of them, part-time job is not a stepping stone but rather a dead end on the labour market.
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| 40. |
- Ottosson, Anders, 1978-, et al.
(författare)
-
A mathematical model of heat and mass transfer in Yankee drying of tissue
- 2017
-
Ingår i: Drying Technology. - : Taylor & Francis. - 0737-3937 .- 1532-2300. ; 35:3, s. 323-334
-
Tidskriftsartikel (refereegranskat)abstract
- Final dewatering in the production of dry creped tissue is performed by Yankee drying, which includes hot pressing followed by simultaneous contact and impingement drying. The present study models Yankee drying and compares simulation results to the data obtained from trials on a pilot tissue machine. It advances models published previously by the representations developed for the transport of heat in the pressing stage and for the heat transfer involved in the dehydration of the cylinder coating spray. The model predicts an average specific drying rate within 4% in the range of the experimental data used.
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| 41. |
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| 42. |
- Ottosson, Jonas, et al.
(författare)
-
A compact field weakening controller implementation
- 2006
-
Ingår i: International Symposium on Power Electronics, Electrical Drives, Automation and Motion, 2006. SPEEDAM 2006. ; 2006, s. 696-700
-
Konferensbidrag (refereegranskat)abstract
- This paper proposes a compact field weakening controller (FWC). The FWC was developed during the development of an electrically driven rear axle for a hybrid electric car. The overall control system of the vehicle, the hybrid controller (HC), delivers a reference torque for the rear drive unit (RDU). Depending on the torque reference, instantaneous vehicle speed and battery voltage the task of the FWC is to produce current references for the current controller. The references are chosen to give an optimal current, optimal in the sense that the torque-per-current ratio is maximized, under the restriction of keeping the stator voltage and current limited. The FWC is based on comprehensive measurements of the machine. An algorithm is used to process the data from the measurements. The output from the algorithm is look-up tables. Implementation of the look-up tables is also discussed in the paper.
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| 43. |
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| 44. |
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| 45. |
- Ottosson, Jonas
(författare)
-
Energy Management and Control of Electrical Drives in Hybrid Electrical Vehicles
- 2007
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hybrid vehicles have attracted tremendous attention during the last years. Increasing environmental concern and a steady increase in fuel prices are key factors for the growing interest. Hybrid vehicles, which benefits from having at least two different energy converters and two different energy storage systems, have proven to have significant potential to improve fuel economy without reducing the performance of the vehicle. However, the extra degree of freedom inherited by the use of two energy sources on-board the vehicle, gives rise to a more complicated energy management control. The first part of the thesis treats the subject of energy management in hybrid electrical vehicles. The gain in fuel consumption and the minimization of emissions are highly dependent on the performance of the control strategy. A rather simple heuristic control strategy presented in the literature is optimized. Heuristic control strategies are often referred to as hard to tune, and none optimal. However, the result presented in the thesis shows that the strategy is easily tuned, robust and has no significant cycle-beating trait. Dynamic programming is used to obtain a global optimal solution to the control problem. The result of this global optimization is then used as a basis for evaluating the real-time heuristic control strategy and serves as a lower bound for the fuel consumption for a given cycle. A comparison of fuel consumption for the two control strategies shows that, though being quite simple, the heuristic control strategy gives a relatively near-optimal result. The second part of the thesis is devoted to the development of an electrically driven rear axle for a HEV in collaboration with SAAB Automobile. A rear drive unit, consisting of an electrical machine, planetary gear and a differential, was provided by SAAB. Focus is on control and thermal modeling of the electrical machine. A simple and effective field weakening controller, giving fast field weakening performance is proposed. The fast field weakening performance is important in a HEV since the battery voltage undergoes rapid variations, during accelerations. In addition to this, the FWC minimizes the torque-per-current ratio by, for a given torque, using the current combination yielding the minimal stator current. In addition to this, a thermal model based on several thermal measurements is proposed and validated against data. The thermal model forms the basis for the derivation of an over temperature controller, preventing the machine from over heating.
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| 46. |
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| 47. |
- Ottosson, Jonas
(författare)
-
Thermal Modelling of Power Modules in a Hybrid Vehicle Application
- 2013
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hybrid electric and full electric vehicles have attracted growing attention during the last decade. This is a consequence of several factors, such as growing environmental concerns, increasing oil prices and a strive for oil independency. Hybrid vehicles have proven to have significant potential to improve fuel economy and at the same time enhance the performance of the vehicle. For the hybrid cars to really penetrate the passenger car market, it is of vital importance that the cost of hybridization can be kept as low as possible and that the increased cost will be paid back within a reasonable time horizon. In addition to this, high reliability of the additional electrical drive system (EDS) needs to be ensured. The power electronics (PE) of the EDS is often packaged into some kind of standalone housing. An alternative solution is to integrate the power electronic inverter and the electric machine into one unit, sharing the same cooling system. This will reduce the packaging volume and at the same time omit the need for the expensive connectors and cables. The integration has other benefits such as, modularity and no separate housing for the inverter is required. All of the above mentioned benefits of the system integration lead to reduced costs of the system and in the long run a reduced price of the vehicle. However, integrating the PE and ETM into one unit makes the thermal design more difficult. This thesis focuses on determining the required cooling capacity of the cooling system, which is an important task, both from a reliability and cost perspective. Long lifetime or high reliability is important for customer acceptance. Performing simulations of power inverter systems, where both the electrical and thermal response is incorporated, often referred to as electro-thermal simulations, is a difficult task due to the different time scales of the two disciplines. If every switching instant is to be simulated, simulation times in the range of microseconds have to be used. Simulating inverter systems in a hybrid vehicle application, where driving cycles lasting for thousands of seconds normally is used, requires unreasonable simulation times. The thesis presents a method for solving this problem. Several electro-thermal simulations are carried out in order to determine the cooling requirements and its effect on module reliability of the inverter. The foundation for these simulations is a simulation model of the electrical drive system, where the main focus is on the thermal model of the inverter itself. The thesis presents a thermal model development procedure to derive simplified thermal models based on thermal impedances. Thermal models for a range of power modules, including both Si and SiC based modules, are presented. Different types of assemblies with single-sided cooling are thoroughly examined in the thesis. In addition to the different single-sided cooled module assemblies, one assembly with double-sided cooling is studied. The thesis shows that the type of layout and assembly greatly affects the thermal behaviour, and as a consequence the lifetime, of the power module. In addition to different module assemblies and cooling options, the system is evaluated for different driving cycles and cooling medium temperatures, together with a comparison of using a fixed and variable switching frequency. The thesis shows that using a variable switching frequency has a significant impact on the cooling requirements.
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| 48. |
- Ottosson, Lars-Göran, et al.
(författare)
-
Robustness analysis of HOG pathway related genes in budding yeast
- 2007
-
Ingår i: ICSB 2007 Conference Proceedings, 8th International Conference on Systems Biology (ICSB2007), October 1-6, 2007.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We applied a novel genetic screening method, named “genetic tug-of-war” (gTOW) to estimate the upper limit of gene copy numbers in Saccharomyces cerevisiae. The study involved 29 HOG pathway related genes which included kinases, phosphatases and transcription factors to cover different set of players in the signal transduction system. In addition a phenotypic profiling was conducted in four different growth conditions with three outputs: lag phase, growth phase and efficiency of growth. A number of interesting hits were identified, including PBS2 which had low numbers of gene copies. It will be of interest to expand the study to encompass the entire known signal transduction system in yeast to search for sensitive nodes.
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| 49. |
- Ottosson, Lars-Göran, et al.
(författare)
-
Robustness and fragility in the yeast High Osmolarity Glycerol (HOG) signal transduction pathway
- 2009
-
Ingår i: Abstracts of the 24th International Conference on Yeast Genetics and Molecular Biology (Supplement to Yeast Volume 26 Issue S1), 25th International Conference on Yeast Genetics & Molecular Biology, July 19-24, Manchester, UK. ; 26:Issue S1
-
Konferensbidrag (refereegranskat)abstract
- Cellular signalling networks integrate environmental stimuli with information on cellular status. These networks must be robust against stochastic fluctuations in stimuli as well as in the amounts of signalling components. Here, we challenge the yeast HOG signal transduction pathway with systematic perturbations in components’ expression levels implemented by a “genetic tug-of-war” methodology under various external conditions in search of nodes of fragilities. We observe a substantially higher frequency of fragile nodes in this signal transduction pathway than has been observed for other cellular processes. These fragilities disperse without any clear pattern over biochemical functions or location in pathway topology, with the most sensitive node being the scaffold protein PBS2. They are also largely independent of pathway activation by external stimuli. However, the strongest toxicities are caused by pathway hyperactivation. In silico analysis highlights the impact of model structure on in silico robustness, and suggests complex formation and scaffolding as important contributors to the observed fragility patterns. Thus, in vivo robustness data can be used to discriminate and improve mathematical models.
|
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| 50. |
- Ottosson, Lars-Göran, et al.
(författare)
-
Sulfate assimilation mediates tellurite reduction and toxicity in Saccharomyces cerevisiae
- 2010
-
Ingår i: Eukaryotic Cell. - 1535-9778 .- 1535-9786. ; 9:10, s. 1635-1647
-
Tidskriftsartikel (refereegranskat)abstract
- Despite a century of research and increasing environmental and human health concerns, the mechanistic basis of the toxicity of derivatives of the metalloid tellurium, Te, in particular the oxyanion tellurite, Te(IV), remains unsolved. Here, we provide an unbiased view of the mechanisms of tellurium metabolism in the yeast Saccharomyces cerevisiae by measuring deviations in Te-related traits of a complete collection of gene knockout mutants. Reduction of Te(IV) and intracellular accumulation as metallic tellurium strongly correlated with loss of cellular fitness, suggesting that Te(IV) reduction and toxicity are causally linked. The sulfate assimilation pathway upstream of Met17, in particular, the sulfite reductase and its cofactor siroheme, was shown to be central to tellurite toxicity and its reduction to elemental tellurium. Gene knockout mutants with altered Te(IV) tolerance also showed a similar deviation in tolerance to both selenite and, interestingly, selenomethionine, suggesting that the toxicity of these agents stems from a common mechanism. We also show that Te(IV) reduction and toxicity in yeast is partially mediated via a mitochondrial respiratory mechanism that does not encompass the generation of substantial oxidative stress. The results reported here represent a robust base from which to attack the mechanistic details of Te(IV) toxicity and reduction in a eukaryotic organism.
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