| 1. |
- Bergqvist, Joakim, et al.
(författare)
-
Detection and Isolation of Sindbis Virus from Mosquitoes Captured During an Outbreak in Sweden, 2013
- 2015
-
Ingår i: Vector Borne and Zoonotic Diseases. - : Mary Ann Liebert Inc. - 1530-3667 .- 1557-7759. ; 15:2, s. 133-140
-
Tidskriftsartikel (refereegranskat)abstract
- Mosquito-borne alphaviruses have the potential to cause large outbreaks throughout the world. Here we investigated the causative agent of an unexpected Sindbis virus (SINV) outbreak during August-September, 2013, in a previously nonendemic region of Sweden. Mosquitoes were collected using carbon dioxide-baited CDC traps at locations close to human cases. The mosquitoes were initially screened as large pools by SINV-specific quantitative RT-PCR, and the SINV-positive mosquitoes were species determined by single-nucleotide polymorphism (SNP) analysis, followed by sequencing the barcoding region of the cytochrome oxidase I gene. The proportion of the collected mosquitoes was determined by a metabarcoding strategy. By using novel strategies for PCR screening and genetic typing, a new SINV strain, Lovanger, was isolated from a pool of 1600 mosquitoes composed of Culex, Culiseta, and Aedes mosquitoes as determined by metabarcoding. The SINV-positive mosquito Culiseta morsitans was identified by SNP analysis and sequencing. After whole-genome sequencing and phylogenetic analysis, the SINV Lovanger isolate was shown to be most closely similar to recent Finnish SINV isolates. In conclusion, within a few weeks, we were able to detect and isolate a novel SINV strain and identify the mosquito vector during a sudden SINV outbreak.
|
|
| 2. |
- Daroui, Danesh, et al.
(författare)
-
Projekt: Kretsbaserad lösare för elektromagnetisk analys av kraftelektroniksystem- Applikation mot IGBTmoduler
- 2007
-
Annan publikation (populärvet., debatt m.m.)abstract
- Projektet syftar till att accelerera och adaptera den programvara, MultiPEEC,som ingick i ELEKTRA-projekt 36021 för att möjliggöra studier avelektromagnetiska effekter i avancerade kraftelektroniksystem.Programvaran bygger på en långsiktig forskningssatsning på Luleå tekniskauniversitet med syfte att kombinera lösningen av elektriska kretsar ochelektromagnetiska effekter i samma miljö med hjälp av en ekvivalent-kretsmetod(PEEC).I första delen av projektet verifierades, optimerades och stabiliseradesprogramvaran i ett mycket nära samarbete med ABB CRC. I den föreslagnaandra delen av projektet kommer programvaran att massivt accelereras föratt möjliggöra detaljstudier av elektromagnetiska effekter i bus bars ochIGBT moduler. För bus bars är det främst studier av parasitiska induktanseroch magnetiska fältmönster som är av intresse för att minimeraoscillationer, spänningstoppar och sk termiska hot spots. För IGBTmodulerna är det främst den dynamiska strömfördelningen i modulerna ochöver seriekopplade konfigurationer som studeras för att förbättrakommande produkter. Exakt med vilken metod den egen-utveckladeprogramvara kommer att accelereras utifrån bestäms under hösten 2010med en litteraturstudie som bas. Tänkbara metoder är QR decomposition,Fast multipole methods, wavelets, eller hierarkiska matrismetoder. Detprimära syftet är att accelerera lösningen av system beskrivna i frekvensdomänen under kvasi-statiska antaganden formulerade med hälp av enmodifierad nodanalys (MNA) då det passar för ovan nämnda designstudier.Vidare är det av stor vikt att kunna uppskatta felet som dessaaccelerationsmetoder introducerar i lösningen så verktyget inte blir praktisktoanvändbart.
|
|
| 3. |
- Engdahl, Cecilia, et al.
(författare)
-
Identification of Swedish mosquitoes based on molecular barcoding of the COI gene and SNP analysis
- 2014
-
Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 14:3, s. 478-488
-
Tidskriftsartikel (refereegranskat)abstract
- Mosquito-borne infectious diseases are emerging in many regions of the world. Consequently, surveillance of mosquitoes and concomitant infectious agents is of great importance for prediction and prevention of mosquito-borne infectious diseases. Currently, morphological identification of mosquitoes is the traditional procedure. However, sequencing of specified genes or standard genomic regions, DNA barcoding, has recently been suggested as a global standard for identification and classification of many different species. Our aim was to develop a genetic method to identify mosquitoes and to study their relationship. Mosquitoes were captured at collection sites in northern Sweden and identified morphologically before the cytochrome c oxidase subunit I (COI) gene sequences of 14 of the most common mosquito species were determined. The sequences obtained were then used for phylogenetic placement, for validation and benchmarking of phenetic classifications and finally to develop a hierarchical PCR-based typing scheme based on single nucleotide polymorphism sites (SNPs) to enable rapid genetic identification, circumventing the need for morphological characterization. The results showed that exact phylogenetic relationships between mosquito taxa were preserved at shorter evolutionary distances, but at deeper levels, they could not be inferred with confidence using COI gene sequence data alone. Fourteen of the most common mosquito species in Sweden were identified by the SNP/PCR-based typing scheme, demonstrating that genetic typing using SNPs of the COI gene is a useful method for identification of mosquitoes with potential for worldwide application.
|
|
| 4. |
- Engdahl, Cecilia, et al.
(författare)
-
The Rift Valley Fever virus protein NSm and putative cellular protein interactions
- 2012
-
Ingår i: Virology Journal. - 1743-422X. ; 9, s. 139-
-
Tidskriftsartikel (refereegranskat)abstract
- Rift Valley Fever is an infectious viral disease and an emerging problem in many countries of Africa and on the Arabian Peninsula. The causative virus is predominantly transmitted by mosquitoes and high mortality and abortion rates characterize outbreaks in animals while symptoms ranging from mild to life-threatening encephalitis and hemorrhagic fever are noticed among infected humans. For a better prevention and treatment of the infection, an increased knowledge of the infectious process of the virus is required. The focus of this work was to identify protein-protein interactions between the non-structural protein (NSm), encoded by the M-segment of the virus, and host cell proteins. This study was initiated by screening approximately 26 million cDNA clones of a mouse embryonic cDNA library for interactions with the NSm protein using a yeast two-hybrid system. We have identified nine murine proteins that interact with NSm protein of Rift Valley Fever virus, and the putative protein-protein interactions were confirmed by growth selection procedures and beta-gal activity measurements. Our results suggest that the cleavage and polyadenylation specificity factor subunit 2 (Cpsf2), the peptidyl-prolyl cistrans isomerase (cyclophilin)-like 2 protein (Ppil2), and the synaptosome-associated protein of 25 kDa (SNAP-25) are the most promising targets for the NSm protein of the virus during an infection.
|
|
| 5. |
- Gupta, Priti, et al.
(författare)
-
Impact of estrogen on IgG glycosylation and serum protein glycosylation in a murine model of healthy postmenopause.
- 2023
-
Ingår i: Frontiers in endocrinology. - 1664-2392. ; 14
-
Tidskriftsartikel (refereegranskat)abstract
- The glycosylation of immunoglobulin (Ig) G regulates IgG interaction capability with Fc gamma receptors found in all immune cells. In pathogenic conditions, estrogen can impact IgG levels and glycosylation. Following menopause, when estrogen levels decline affecting the immune system and potentially leading to a heightened susceptibility of immune activation.In this study, we aim to determine if estrogen levels can regulate IgG glycosylation in postmenopausal healthy situations.Mice were ovariectomized to simulate an estrogen-deficient postmenopausal status and then treated with 17-beta-estradiol (E2) at different doses and different administration strategies.Using a highly sensitive liquid chromatography-tandem mass spectrometry (MS/MS) glycoproteomic method, we demonstrated that E2 treatment increased the degree of glycosylation on IgG-Fc with both galactosylation and sialylation in the position required for interaction with Fc gamma receptors. We also observed that only long-term estrogen deficiency reduces IgG levels and that estrogen status had no impact on total IgG sialylation on both Fab and Fc domains or general glycoprotein sialylation evaluated by ELISA. Furthermore, E2 status did not affect the total sialic acid content of total cells in lymphoid organs and neither B cells nor plasma cells.The study concluded that E2 treatment does not affect total serum glycoprotein sialylation but alters IgG glycosylation, including IgG sialylation, implying that estrogen functions as an intrinsic modulator of IgG sialylation and could thereby be one pathway by which estrogen modulates immunity.
|
|
| 6. |
- Löfstrand, Sofia, et al.
(författare)
-
Feasibility of Electrifying Urban Goods Distribution Trucks
- 2013
-
Ingår i: SAE International Journal of Commercial Vehicles. - : SAE International. - 1946-391X .- 1946-3928. ; 6:1, s. 24-33
-
Tidskriftsartikel (refereegranskat)abstract
- This paper discusses the feasibility of electrifying medium to heavy urban goods distribution trucks. As a case study, an existing transport system in the Swedish city of Gothenburg is used. The project is a joint research effort between a vehicle OEM, an electric utility, a fleet operator, the Swedish Transport Administration and two research organizations. One main objective is to determine if and when different electrified powertrains are cost efficient to the end user. The results indicate that by 2015 conventional powertrains are still probably the most cost effective alternative in all applications studied. But in 2025, electrified powertrains are most cost efficient for most transport scenarios. These results indicate a transition in preferred powertrain technology for urban trucks within the coming ten years. It is important to point out that this result may not be general. Driving patterns, energy price developments and technology maturity of components such as batteries and motors greatly influence the total cost of ownership and large regional differences in when such a transition may occur are expected. In addition to the total cost of ownership, important issues for a successful deployment are policies (e.g. restricting access to urban areas for noisy and polluting vehicles), information and communication solutions (e.g. adapted route planning), access to a cost effective charging infrastructure (and low-carbon electricity production) and new business models. These must all be developed in parallel to the vehicle and powertrain technology. The large number of different stakeholders involved in this transition is also a challenge in itself.
|
|
| 7. |
- Löfström Engdahl, Elin, 1983, et al.
(författare)
-
Purification of used scintillation liquids containing the alpha emitters americium and plutonium
- 2015
-
Ingår i: Journal of Radioanalytical and Nuclear Chemistry. - : Springer Science and Business Media LLC. - 0236-5731 .- 1588-2780. ; 303:2, s. 1133-1136
-
Tidskriftsartikel (refereegranskat)abstract
- In Sweden, alpha radioactive waste liquids withan activity over some kBq per waste container cannot besent for final storage. Therefore, in this work, a method fora purification of alpha active scintillation cocktails wasdeveloped. Until today (March, 2013) more than 20 L ofscintillation liquids have successfully been purified fromamericium and plutonium. The products of the process area solid fraction that can be sent to final storage and apractically non-radioactive liquid fraction that can be sentto municipal incineration.
|
|
| 8. |
- Nilsson, Anton, et al.
(författare)
-
Examining the continuum of resistance model in two population-based screening studies in Sweden
- 2023
-
Ingår i: Preventive Medicine Reports. - : Elsevier. - 2211-3355. ; 35
-
Tidskriftsartikel (refereegranskat)abstract
- In studies recruited on a voluntary basis, lack of representativity may impair the ability to generalize findings to the target population. Previous studies, primarily based on surveys, have suggested that generalizability may be improved by exploiting data on individuals who agreed to participate only after receiving one or several reminders, as such individuals may be more similar to non-participants than what early participants are. Assessing this idea in the context of screenings, we compared sociodemographic characteristics and health across early, late, and non-participants in two large population-based screening studies in Sweden: STROKESTOP II (screening for atrial fibrillation; 6,867 participants) and SCREESCO (screening for colorectal cancer; 39,363 participants). We also explored the opportunities to reproduce the distributions of characteristics in the full invited populations, either by assuming that the non-participants were similar to the late participants, or by applying a linear extrapolation model based on both early and late participants. Findings showed that early and late participants exhibited similar characteristics along most dimensions, including civil status, education, income, and health examination results. Both these types of participants in turn differed from the non-participants, with fewer married, lower educational attainments, and lower incomes. Compared to early participants, late participants were more likely to be born outside of Sweden and to have comorbidities, with non-participants similar or even more so. The two empirical models improved representativity in some cases, but not always. Overall, we found mixed support that data on late participation may be useful for improving representativeness of screening studies.
|
|
| 9. |
- Tavakoli, Hanif, 1980-
(författare)
-
A High Frequency Transformer Winding Model for FRA Applications
- 2009
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Frequency response analysis (FRA) is a method which is used to detect mechanical faults in transformers. The FRA response of a transformer is determined by its geometry and material properties, and it can be considered as the transformer’s fingerprint. If there are any mechanical changes in the transformer, for example if the windings are moved or distorted, its fingerprint will also be changed so, theoretically, mechanical changes in the transformer can be detected with FRA. The purpose of this thesis is to partly create a simple model for the ferromagnetic material in the transformer core, and partly to investigate the high frequency part of the FRA response of the transformer winding. To be able to realize these goals, two different models are developed separately from each other. The first one is a time- and frequency domain complex permeability model for the ferromagnetic core material, and the second one is a time- and frequency domain winding model based on lumped circuits, in which the discretization is made finer and finer in three steps. Capacitances and inductances in the circuit are calculated with use of analytical expressions derived from approximated geometrical parameters. The developed core material model and winding model are then implemented in MATLAB separately, using state space analysis for the winding model, to simulate the time- and frequency response. The simulations are then compared to measurements to verify the correctness of the models. Measurements were performed on a magnetic material and on a winding, and were compared with obtained results from the models. It was found that the model developed for the core material predicts the behavior of the magnetic field for frequencies higher than 100 Hz, and that the model for the winding predicts the FRA response of the winding for frequencies up to 20 MHz.
|
|
| 10. |
- Tavakoli, Hanif, 1980-
(författare)
-
An FRA Transformer Model with Application on Time Domain Reflectometry
- 2011
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Frequency response analysis (FRA) is a frequency-domain method which is used to detect mechanical faults in transformers. The frequency response of a transformer is determined by its geometry and material properties, and it can be considered as the transformer’s fingerprint. If there are any mechanical changes in the transformer, for example if the windings are moved or distorted, its fingerprint will also be changed so, theoretically, mechanical changes in the transformer can be detected with FRA. A problem with FRA is the fact that there is no general agreement about how to interpret the measurement results for detection of winding damages. For instance, the interpretation of measurement results has still not been standardized.The overall goal of this thesis is to try to enhance the understanding of the information contained in FRA measurements. This has been done in two ways: (1) by examining the FRA method for (much) higher frequencies than what is usual, and (2) by developing a new method in which FRA is combined with the ideas of Time Domain Reflectometry (TDR). As tools for carrying out the above mentioned steps, models for the magnetic core and the winding have been developed and verified by comparison to measurements.The usual upper frequency limit for FRA is around 2 MHz, which in this thesis has been extended by an order of magnitude in order to detect and interpret new phenomena that emerge at high frequencies and to investigate the potential of this high-frequency region for detection of winding deteriorations.Further, in the above-mentioned new method developed in this thesis, FRA and TDR are combined as a step towards an easier and more intuitive detection and localization of faults in transformer windings, where frequency response measurements are visualized in the time domain in order to facilitate their interpretation.
|
|
