| 1. |
- DAWODY, JAZAER, 1959, et al.
(författare)
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E4-Mistra, a research program for the development of an energy efficient low emission exhaust aftertreatment system for heavy duty vehicles
- 2012
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Ingår i: World Renewable Energy Forum, WREF 2012, Including World Renewable Energy Congress XII and Colorado Renewable Energy Society (CRES) Annual Conference. - : American Solar Energy Society. - 9781622760923 ; , s. 4530-4536
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Konferensbidrag (refereegranskat)abstract
- This paper presents a unique system approach applied in a joint academic - industrial research program, E4 Mistra, to reach the goals of energy efficiency and low emissions exhaust aftertreatment system for heavy duty vehicles. The high energy efficiency is achieved by heat recuperation, on-board hydrogen production for use in both an auxiliary power unit and for NOx reduction and by finding new solutions for making the after-treatment system active at low exhaust temperatures. To reach low particulate emissions a mechanical filter using a sintered metal filter is developed. Low NOx emissions are achieved by an efficient NOx reduction catalyst. The system is based on four technological advances: Thermoelectric material s for heat recuperation, catalytic reduction of NOx over innovative catalyst substrates using hydrocarbons from the fuel and H2 from a high efficiency fuel reformer, and particulate filtration over a porous metal filter.
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| 2. |
- Espling, Daniel, 1983-, et al.
(författare)
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Modeling and Placement of Cloud Services with Internal Structure
- 2016
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Ingår i: IEEE Transactions on Cloud Computing. - : IEEE Computer Society. - 2168-7161. ; 4:4, s. 429-439
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Tidskriftsartikel (refereegranskat)abstract
- Virtual machine placement is the process of mapping virtual machines to available physical hosts within a datacenter or on a remote datacenter in a cloud federation. Normally, service owners cannot influence the placement of service components beyond choosing datacenter provider and deployment zone at that provider. For some services, however, this lack of influence is a hindrance to cloud adoption. For example, services that require specific geographical deployment (due e.g. to legislation), or require redundancy by avoiding co-location placement of critical components. We present an approach for service owners to influence placement of their service components by explicitly specifying service structure, component relationships, and placement constraints between components. We show how the structure and constraints can be expressed and subsequently formulated as constraints that can be used in placement of virtual machines in the cloud. We use an integer linear programming scheduling approach to illustrate the approach, show the corresponding mathematical formulation of the model, and evaluate it using a large set of simulated input. Our experimental evaluation confirms the feasibility of the model and shows how varying amounts of placement constraints and data center background load affects the possibility for a solver to find a solution satisfying all constraints within a certain time-frame. Our experiments indicate that the number of constraints affects the ability of finding a solution to a higher degree than background load, and that for a high number of hosts with low capacity, component affinity is the dominating factor affecting the possibility to find a solution.
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| 3. |
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| 4. |
- DAWODY, JAZAER, 1959, et al.
(författare)
-
An integrated system for energy-efficient exhaust aftertreatment for heavy-duty vehicles
- 2015
-
Ingår i: Renewable Energy in the Service of Mankind. - Cham : Springer International Publishing. - 9783319177779 - 9783319177762 ; 1, s. 133-143
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- © Springer International Publishing Switzerland 2015. This chapter presents a unique system approach applied in a joint academic- industrial research programme, E4 Mistra, to attain the goals of high energy efficiency and low emissions in an exhaust aftertreatment system for heavy-duty vehicles. The high energy efficiency is achieved by heat recuperation, onboard hydrogen production for NOx reduction, and by finding new solutions for making the aftertreatment system active at low exhaust temperatures. To reach low particulate emissions, a mechanical filter using a sintered metal powder is developed and coated with catalytic material to improve the soot oxidation efficiency. Low NOx emissions are achieved by an efficient NOx reduction catalyst. The integrated E4 Mistra system comprises four technological advances: thermoelectric (TE) materials for heat recuperation, catalytic reduction of NOx over innovative catalyst substrates using either the onboard diesel or biodiesel, H2 from a high-efficiency fuel reformer, and particulate filtration over a porous metal filter. The TE materials are used in a TE generator (TEG) which converts thermal energy into electricity. The TEG is used to recuperate heat from the exhaust-gas recirculation (EGR) circuit of heavy-duty trucks and is expected to generate ~1 kW electric power from 20 kW heat in the exhaust gas. The TEG is integrated in a plate heat exchanger (HEX) designed particularly for this application. Apart from the knowledge and experiences in TEG and heat exchange technologies, a thorough fluid dynamics and TE analysis are performed in this project to understand the governing processes and optimize the system accordingly. The components of the E4 Mistra system are explained in the chapter in addition to test results, which show the system's capacity for H2 production, NOx conversion, particulate matter filtration and soot oxidation, and finally electric power generation via heat recuperation from the exhaust gas using the developed TEG-HEX system.
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| 5. |
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| 6. |
- Larsson, Lars, 1983-, et al.
(författare)
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Scheduling and Monitoring of Internally Structured Services in Cloud Federations
- 2011
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Ingår i: 2011 IEEE Symposium on Computers and Communications (ISCC). - : IEEE. - 9781457706783 - 9781457706806 ; , s. 173-178
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Konferensbidrag (refereegranskat)abstract
- Cloud infrastructure providers may form Cloud federations to cope with peaks in resource demand and to make large-scale service management simpler for service providers. To realize Cloud federations, a number of technical and managerial difficulties need to be solved. We present ongoing work addressing three related key management topics, namely, specification, scheduling, and monitoring of services. Service providers need to be able to influence how their resources are placed in Cloud federations, as federations may cross national borders or include companies in direct competition with the service provider. Based on related work in the RESERVOIR project, we propose a way to define service structure and placement restrictions using hierarchical directed acyclic graphs. We define a model for scheduling in Cloud federations that abides by the specified placement constraints and minimizes the risk of violating Service-Level Agreements. We present a heuristic that helps the model determine which virtual machines (VMs) are suitable candidates for migration. To aid the scheduler, and to provide unified data to service providers, we also propose a monitoring data distribution architecture that introduces cross-site compatibility by means of semantic metadata annotations.
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| 7. |
- Larsson, Malin, 1983-, et al.
(författare)
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A new ultrasound-based approach to visualize target specific polymeric contrast agent
- 2011
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Ingår i: 2011 IEEE International Ultrasonics Symposium (IUS). - : IEEE. - 9781457712524 ; , s. 1626-1629
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Konferensbidrag (refereegranskat)abstract
- There are advantages of using a polymeric shelled contrast agent (CA) during ultrasound imaging instead of lipid shelled CA, e.g. particles can be attached to the surface, which enables an introduction of antibodies to the surface making the CA target specific. For this application it is essential to have a sensitive imaging technique suitable for polymeric CA. However, previously presented results have indicated difficulties in visualizing polymeric CA with commercially available contrast algorithms. Therefore a new subtraction algorithm (SA), was developed that define the difference between contrast and reference images. The aim of this study was to evaluate the response from a polymeric CA, when using the SA and compare it with existing contrast algorithms. Moreover, the possibility to detect a thin layer of CA was tested using the SA.Ultrasound short-axis images of a tissue-mimicking vessel phantom with a pulsating flow were obtained using a GE Vivid7 system (M12L) and a Philips iE33 system (S5-1). Repeated (n=91) contrast to tissue ratios (CTR) calculated at various mechanical index (MI) using the contrast algorithms pulse inversion (PI), power modulation (PM) and SA at a concentration of 105microbubbles/ml.The developed SA showed improvements in CTR compared to existing contrast algorithms. The CTRs were -0.99 dB ± 0.67 (MI 0.2), 9.46 dB ± 0.77 (MI 0.4) and 2.98 dB ± 0.60 (MI 0.8) with PI, 8.17 dB ± 1.15 (MI 0.2), 15.60 dB ± 1.29 (MI0.4) and 11.60 dB ± 0.73 (MI 0.8) with PM and 14.97 dB ± 3.97 (MI 0.2), 20.89 dB ± 3.54 (MI 0.4) and 21.93 dB ± 4.37 (MI 0.8) with the SA. In addition to this, the layer detection, when using the SA was successful.
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| 8. |
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| 9. |
- Sarlin, Paul-Edouard, et al.
(författare)
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Back to the Feature: Learning Robust Camera Localization from Pixels to Pose
- 2021
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Ingår i: Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition. - 1063-6919. ; , s. 3246-3256
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Konferensbidrag (refereegranskat)abstract
- Camera pose estimation in known scenes is a 3D geometry task recently tackled by multiple learning algorithms. Many regress precise geometric quantities, like poses or 3D points, from an input image. This either fails to generalize to new viewpoints or ties the model parameters to a specific scene. In this paper, we go Back to the Feature: we argue that deep networks should focus on learning robust and invariant visual features, while the geometric estimation should be left to principled algorithms. We introduce PixLoc, a scene-agnostic neural network that estimates an accurate 6-DoF pose from an image and a 3D model. Our approach is based on the direct alignment of multiscale deep features, casting camera localization as metric learning. PixLoc learns strong data priors by end-to-end training from pixels to pose and exhibits exceptional generalization to new scenes by separating model parameters and scene geometry. The system can localize in large environments given coarse pose priors but also improve the accuracy of sparse feature matching by jointly refining keypoints and poses with little overhead. The code will be publicly available at github.com/cvg/pixloc.
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| 10. |
- Afshari, Alireza, 1956, et al.
(författare)
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Quantification of ultrafine particles from second-hand tobacco smoke infiltration
- 2010
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Ingår i: Proceedings of the CLIMA 2010 Conference: 10th REHVA World Congress 'Sustainable Energy use in Buildings', 8 pages.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents some of the results of a second-hand tobacco smoke intervention studycarried out in 19 flats in four different buildings. Two of the investigated buildings were nonrenovatedand two others were renovated. The aim of the study was to quantify infiltration ofultrafine particles from a smoker's flat into a non-smoker's flat. In addition, several tests werecarried out to describe some solutions for reduction of particle concentrations in the smoker'sflat and the non-smoker's flat. The air change rates and the indoor particle concentrationswere measured continuously during the measuring periods. The particle sources (particlegenerating activities) were cigarette-burning in the un-occupied buildings and candle-burningin the occupied buildings. Reductions of the concentration of ultrafine particles using aircleaning devices were studied. Results showed that the transfer of ultrafine particles wasabout 9% when the source flat was located below the receiving flat, whereas the transfer was1-2% when the source flat was on the same floor as, or above, the receiving flat.
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| 11. |
- Comasco, Erika, et al.
(författare)
-
Adipocytokines levels at delivery, functional variation of TFAP2 beta, and maternal and neonatal anthropometric parameters
- 2013
-
Ingår i: Obesity. - : Wiley. - 1930-7381 .- 1930-739X. ; 21:10, s. 2130-2137
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVEAdipocytokines participate in the regulation of glucose metabolism and foetal development. The transcription factor activating protein 2B (TFAP2β) has been associated with adipocytokine regulation, and gene variations with type 2 diabetes and obesity. This study investigated associations between maternal TFAP2B variation, adipocytokines levels and maternal and neonatal anthropometric characteristics.DESIGN AND METHODSA population-based sample of women was followed from delivery to six months postpartum. Adiponectin, leptin and interleukin-6 levels at delivery, and maternal as well as neonatal anthropometric variables were assessed. The TFAP2β intron 1 variable number tandem repeat (VNTR) was genotyped.RESULTSMaternal interleukin-6 correlated positively with leptin at delivery, with peripartum weight changes and weight of newborn males, adjusted for potential confounders. Leptin at delivery was associated with TFAP2β intron 1 VNTR genotype, adjusted for confounders, maternal weight and negatively with birth weight among female neonates. A path model suggested a link between TFAP2β genotype, leptin levels and newborn females' weight.CONCLUSIONSThe present results stress a role for the TFAP2 β in adiposity-related conditions and intrauterine growth. The association between neonatal birth weight and maternal adipocytokine levels, together with the observed sex effect, call for further studies on the mechanisms behind neuro-endocrine foetal programming.
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| 12. |
- Elmroth, Erik, 1964-, et al.
(författare)
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Interfaces for Placement, Migration, and Monitoring of Virtual Machines in Federated Clouds
- 2009
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Ingår i: Proceedings of the Eighth International Conference on Grid and Cooperative Computing (GCC 2009). - : IEEE Computer Society Press. - 9780769537665 ; , s. 253-260
-
Konferensbidrag (refereegranskat)abstract
- Current cloud computing infrastructure offerings are lacking in interoperability, which is a hindrance to the advancement and adoption of the cloud computing paradigm. As clouds are made interoperable, federations of clouds may be formed. Such federations are from the point of view of the user not burdened by vendor lock-in, and opens for business possibilities where a market place of cloud computing infrastructure can be formed. Federated clouds require unified management interfaces regarding the virtual machines (VMs) that comprise the services running in the cloud federation. Standardization efforts for the required management interfaces have so far focused on definition of description formats regarding VMs, and the control of already deployed VMs. We propose technology neutral interfaces and architectural additions for handling placement, migration, and monitoring of VMs in federated cloud environments, the latter as an extension of current monitoring architectures used in grid computing. The interfaces presented adhere to the general requirements of scalability, efficiency, and security in addition to specific requirements related to the particular issues of interoperability and business relationships between competing cloud computing infrastructure providers. In addition, they may be used equally well locally and remotely, creating a layer of abstraction that simplifies management of virtualized service components.
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| 13. |
- Froitzheim, Jan, 1981, et al.
(författare)
-
Chromium evaporation of Coated and uncoated FE-22CR steels investigated by a novel denuder technique
- 2009
-
Ingår i: 3rd European Fuel Cell Technology and Applications - Piero Lunghi Conference, EFC 2009; Rome; Italy; 15 December 2009 through 18 December 2009. - 9788882862114 ; , s. 77-78
-
Konferensbidrag (refereegranskat)abstract
- The formation of volatile chromium species is a major problem concerning metallic interconnects for Solid Oxide Fuel Cells (SOFC). This problem is known and a number of routes, usually in the form of coatings, has been presented to overcome this problem. This paper investigates the influence of thin metallic films which can be applied by a low cost process. The measurements are carried out by a novel denuder technique where volatile chromium species are collected as sodium chromate. This technique allows the quantification of chromium evaporation in a time resolved manner. Coated and uncoated samples of ferritic steels developed for SOFC applications are investigated at 850°C in a N2-O2-H2O environment.
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| 14. |
- Froitzheim, Jan, 1981, et al.
(författare)
-
Cr evaporation of metallic interconnects: A novel method for quantification
- 2009
-
Ingår i: ECS Transactions. - : The Electrochemical Society. - 1938-5862 .- 1938-6737. - 9781566777391 ; 25:2 PART 2, s. 1423-1428
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Konferensbidrag (refereegranskat)abstract
- Chromium evaporation from metallic interconnects in SOFCs is commonly poisoning the cathode of SOFCs. To reduce chromium evaporation, rather thick coatings have been deposited using various coating techniques. In this study, a 22% Cr ferritic steel has been coated with thin films (
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| 15. |
- Froitzheim, Jan, 1981, et al.
(författare)
-
Investigation of Chromium Volatilization from FeCr Interconnects by a Denuder Technique
- 2010
-
Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 157:9, s. B1295-B1300
-
Tidskriftsartikel (refereegranskat)abstract
- A technique is presented for accurate and time-resolved quantification of chromium volatilization from alloys at high temperature. A denuder tube which is coated with Na2CO3 is placed downstream of the samples. CrO2(OH)(2) that evaporated from the samples is collected on the denuder and converted to the thermally stable Na2CrO4. The chromate is then dissolved in water and determined quantitatively. Three commercially available ferritic 22% Cr steels intended for use as solid oxide fuel cell interconnect materials (Sanergy HT, Crofer 22 APU, and ZMG 232) have been investigated with respect to chromium volatilization and oxidation rate. The effect on chromium volatilization of a submicrometer cobalt coating on the steel surface is reported. Comparisons are made with a conventional thick ceramic coating. The experiments are carried out at 850 degrees C in N-2 - 20% O-2 - 3% H2O atmosphere. The submicrometer Co coatings proved to be very efficient, reducing Cr volatilization by 1 order of magnitude. Microscopic studies show that both uncoated steel and steel coated with a submicrometer cobalt film develop two-layered oxide scales with the bottom part consisting of a Cr-rich corundum-type oxide. The uncoated samples develop a top layer consisting of (Cr, Mn)(3)O-4 oxide, whereas the Co-coated samples exhibit a top layer consisting of Co-rich spinel oxide. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3462987] All rights reserved.
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| 16. |
- Ghaffari, Roujin, 1994, et al.
(författare)
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Effect of alkalinity on the diffusion of solvent-fractionated lignin through cellulose membranes
- 2023
-
Ingår i: Cellulose. - : Springer Science and Business Media LLC. - 0969-0239 .- 1572-882X. ; 30:6, s. 3685-3698
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Tidskriftsartikel (refereegranskat)abstract
- Mass transport of liberated lignin fragments from pits and fiber walls into black liquor is considered a determining step in the delignification process. However, our current understanding of the diffusion of lignin through cellulose and the influential parameter on this process is very limited. A comprehensive and detailed study of lignin mass transport through cellulosic materials is, therefore, of great importance. In this study, diffusion cell methodology is implemented to systematically investigate the transport of fractionated kraft lignin molecules through model cellulose membranes. Pulping is a complex process and lignin is very heterogenous material therefore to perform a more detailed study on lignin diffusion, we included an additional solvent fractionation step. One of the benefits of this method is that the setup can be adjusted to various experimental conditions allowing the complex chemical reactions occurring during pulping, which would affect the mass transfer of lignin, to be avoided. Here, the effects of the alkalinity of the aqueous solution and molecular weight of the kraft lignin molecules on their diffusion were investigated. Additionally, NMR spectroscopy, size exclusion chromatography, and UV/Vis spectroscopy were used to characterize the starting material and the molecules that passed through the membrane. Lignin molecules detected in the acceptor chamber of the diffusion cells had lower molecular weights, indicating a size fractionation between the donor and acceptor chamber. UV/Vis showed higher concentrations of ionized conjugated kraft lignin molecules in the acceptor chamber, which is a sign of chemical fractionation. This study suggests that the diffusion of lignin through small cellulose pores can be enhanced by decreasing the average molecular weight of the diffusing kraft lignin molecules and increasing alkalinity.
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| 17. |
- Gunnarsson, Lina-Maria, 1977, et al.
(författare)
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Comparison of six different sewage treatment processes-Reduction of estrogenic substances and effects on gene expression in exposed male fish
- 2009
-
Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 407:19, s. 5235-5242
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Tidskriftsartikel (refereegranskat)abstract
- Treated sewage effluents often contain a mixture of estrogenic compounds in low concentrations. The total combined activity of these, however, may be sufficiently high to affect the reproduction of aquatic vertebrates. The introduction of advanced treatment technologies has been suggested as a way to remove micro-contaminants, including estrogenic substances. In this study, one municipal influent was treated with six different processes in parallel on a semi-large scale in order to assess their potential to reduce substances that could contribute to estrogenic effects in male fish. The effluent from a conventional, activated sludge treatment line was compared to a similarly treated effluent with a final sand-filtering step. The addition of ozonation (15 g O-3/m(3)). a moving bed biofilm reactor (MBBR) or both in combination was also evaluated. There was also a separate treatment line that was based on a membrane bioreactor. A small battery of hepatic estrogen-responsive genes was measured in the exposed fish using quantitative PCR. Concentrations of steroid estrogens and estrogenic phenols in the effluents were measured by GC-ECNI-MS. The ozonated effluents were the only tested effluents for which all measured biological effects in exposed fish were removed. Chemical data suggested that the MBBR technology was equally effective in removing the analyzed estrogens; however, elevated expression of estrogen-responsive genes suggested that some estrogenic substances were still present in the effluent. The membrane bioreactor removed most of the measured estrogens and it reduced the induction of the estrogen-responsive genes. However, fish exposed to this effluent had significantly enlarged livers. Given that the same influent was treated in parallel with a broad set of technologies and that the chemical analyses were combined with an in vivo assessment of estrogenic responses, this study provides valuable input into the assessment of advanced treatment processes for removing estrogenic substances.
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| 18. |
- Gunnarsson, Lina-Maria, 1977, et al.
(författare)
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Pharmaceutical industry effluent diluted 1:500 affects global gene expression, cytochrome P4501A activity and plasma phosphate in fish
- 2009
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Ingår i: Environmental Toxicology and Chemistry. - : Society of Environmental Toxicology and Chemistry (SETAC). - 0730-7268 .- 1552-8618. ; 28:12, s. 2639-2647
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Tidskriftsartikel (refereegranskat)abstract
- Patancheru, near Hyderabad, India, is a major production site for the global bulk drug market. Approximately 90 manufacturers send their wastewater to a common treatment plant in Patancheru. Extraordinary high levels of a wide range of pharmaceuticals have recently been demonstrated in the treated effluent. As little as 0.2% of this effluent can strongly reduce the growth rate of tadpoles, but the underlying mechanisms of toxicity are not known. To begin addressing how the effluent affects aquatic vertebrates, rainbow trout (Oncorhynchus mykiss) were exposed to 0.2% effluent for five days. Several physiological endpoints, together with effects on global hepatic gene expression patterns, were analyzed. The exposed fish showed both an induction of hepatic cytochrome P450 1A (CYP1A) gene expression, as well as enzyme activity. Clinical blood chemistry analyses revealed an increase in plasma phosphate levels, which in humans indicates impaired kidney function. Several oxidative stress-related genes were induced in the livers; however, no significant changes in antioxidant enzyme activities or in the hepatic glutathione levels were found. Furthermore, estrogen-regulated genes were slightly up-regulated following exposure, and moderate levels of estriol were detected in the effluent. The present study identifies changes in gene expression triggered by exposure to a high dilution of the effluent, supporting the hypothesis that these fish are responding to chemical exposure. The pattern of regulated genes may contribute to the identification of mechanisms of sub-lethal toxicity, as well as illuminate possible causative agents.
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| 19. |
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| 20. |
- Gårdebjer, Sofie, 1985, et al.
(författare)
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Solid-state NMR to quantify surface coverage and chain length of lactic acid modified cellulose nanocrystals, used as fillers in biodegradable composites
- 2015
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Ingår i: Composites Science and Technology. - : Elsevier BV. - 0266-3538. ; 107, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- The surface of cellulose nanocrystals (CNC) was chemically modified with polylactic acid. The modification was characterized by infrared spectroscopy, by monitoring the colloidal behavior of CNC in different solvents, and by quantitative analysis using solid-state NMR (ss-NMR). The quantitative analysis showed that grafted PLA chains on average comprised two lactic acid units attached to 48% of all available hydroxyl groups on the surface of the CNC. Both modified and unmodified CNC were incorporated as fillers in three different biodegradable materials: polylactide acid (PLA), poly(lactide-co-glycolide) (PLGA) and poly(3-hydroxybutyrate) (PHB). Composite films with up to 20 wt% of unmodified and modified CNC were produced via solvent casting. Compared to unmodified CNC, the modified CNC showed less aggregation in organic solvents and hydrophobic polymer materials and increased interaction was seen between the polymer and filler after surface modification. Using ss-NMR, our study shows that even as little as two units of PLA assures stabile CNC dispersions in organic solvents and distribute CNC in hydrophobic polymers.
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| 21. |
- Hossein Nia, Saeed, 1983-, et al.
(författare)
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Simulation-based evaluation of maintenance strategies from a life cycle cost perspective
- 2023
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Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. - 9780646865881 ; 532-533, s. 258-265
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Tidskriftsartikel (refereegranskat)abstract
- A methodology that combines simulations of long-term mechanical degradation including maintenance interventions with an assessment of the associated socio-economic impact is proposed. This development responds to an urgent need within the railway sector to enable the evaluation of maintenance strategies from a LCC perspective. The functionality of the methodology is demonstrated in an investigation of rail grinding strategies for a curve on the Swedish Iron-ore line. The results indicate a reduction in LCC of 50% when using a harder rail material (R400HT) combined with annual rail grinding as compared to a softer rail material (R350LHT) and two grinding campaigns per year.
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| 22. |
- Jakobson Mo, Susanna, et al.
(författare)
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Dopamine transporter imaging with [18F]FE-PE2I PET and [123I]FP-CIT SPECT – a clinical comparison
- 2018
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Ingår i: EJNMMI Research. - : Springer. - 2191-219X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Dopamine transporter (DAT) imaging may be of diagnostic value in patients with clinically suspected parkinsonian disease. The purpose of this study was to compare the diagnostic performance of DAT imaging with positron emission computed tomography (PET), using the recently developed, highly DAT-selective radiopharmaceutical [18F]FE-PE2I (FE-PE2I), to the commercially available and frequently used method with [123I]FP-CIT (FP-CIT) single-photon emission computed tomography (SPECT) in early-stage idiopathic parkinsonian syndrome (PS).Methods: Twenty-two patients with a clinical de novo diagnosis of PS and 28 healthy controls (HC) participating in an on-going clinical trial of FE-PE2I were analyzed in this study. Within the trial protocol, participants are clinically reassessed 2 years after inclusion. A commercially available software was used for automatic calculation of FP-CIT-specific uptake ratio (SUR). MRI-based volumes of interest combined with threshold PET segmentation were used for FE-PE2I binding potential relative to non-displaceable binding (BPND) quantification and specific uptake value ratios (SUVR).Results: PET with FE-PE2I revealed significant differences between patients with a clinical de novo diagnosis of PS and healthy controls in striatal DAT availability (p < 0.001), with excellent accuracy of predicting dopaminergic deficit in early-stage PS. The effect sizes were calculated for FE-PE2I BPND (Glass’s Δ = 2.95), FE-PE2I SUVR (Glass’s Δ = 2.57), and FP-CIT SUR (Glass’s Δ = 2.29). The intraclass correlation (ICC) between FE-PE2I BPND FP-CIT SUR was high in the caudate (ICC = 0.923), putamen (ICC = 0.922), and striatum (ICC = 0.946), p < 0.001. Five of the 22 patients displayed preserved striatal DAT availability in the striatum with both methods. At follow-up, a non-PS clinical diagnosis was confirmed in three of these, while one was clinically diagnosed with corticobasal syndrome. In these patients, FE-PE2I binding was also normal in the substantia nigra (SN), while significantly reduced in the remaining patients. FE-PE2I measurement of the mean DAT availability in the putamen was strongly correlated with BPND in the SN (R = 0.816, p < 0.001). Olfaction and mean putamen DAT availability was correlated using both FE-PE2I BPND and FP-CIT SUR (R ≥ 0.616, p < 0.001).Conclusion: DAT imaging with FE-PE2I PET yields excellent basic diagnostic differentiation in early-stage PS, at least as good as FP-CIT SPECT.
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| 23. |
- Jakobson Mo, Susanna, et al.
(författare)
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VNTR polymorphism in the SLC6A3 gene does not influence dopamine transporter availability measured by [18F]FE-PE2I PET or [123I]FP-Cit SPECT
- 2022
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Ingår i: Nuclear medicine communications. - : Wolters Kluwer. - 0143-3636 .- 1473-5628. ; 43:3, s. 247-255
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To investigate the potential impact of polymorphism in the 3'-untranslated region (3'UTR) of the SLC6A3 gene (DAT1) on normal variation in dopamine transporter (DAT) imaging with [18F]FE-PE2I PET and [123I]FP-Cit SPECT.METHODS: Thirty-six individuals (mean age 70.4±5.4 years) with normal [18F]FE-PE2I PET and [123I]FP-Cit SPECT were genotyped for variable number of tandem repeats (VNTR) in the 3′UTR of the DAT1 gene. The DAT-availability in the caudate and putamen as measured with [18F]FE-PE2I PET and [123I]FP-Cit SPECT, as well as in the substantia nigra with [18F]FE-PE2I PET were compared between the participants carrying one or two 9-repeat alleles (i.e. 9R+10R or 9R+9R; 47%) and the participants without a 9R allele (i.e. 10R+10R or 10R+11R; 53%). Nonparametric tests, linear regression analysis and mixed model analysis were used to assess any statistical difference in measured DAT availability between the two allele groups.RESULTS: The measured DAT-availability in PET- and SPECT-imaging tended to be slightly higher in the 9R-group; however, the difference did not reach statistical significance in either the caudate or the putamen or the substantia nigra. Instead, age did have a significant effect on the DAT level (P < 0.05) notwithstanding the genotype.CONCLUSION: No significant effect of DAT1-genotype was detectable in imaging with [18F]FE-PE2I PET or [123I]FP-Cit, instead, age accounted for the normal variation in DAT-PET and DAT-SPECT.
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| 24. |
- Janewithayapun, Ratchawit, 1998, et al.
(författare)
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Nanostructures of etherified arabinoxylans and the effect of arabinose content on material properties
- 2024
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 331
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Tidskriftsartikel (refereegranskat)abstract
- To further our understanding of a thermoplastic arabinoxylan (AX) material obtained through an oxidation-reduction-etherification pathway, the role of the initial arabinose:xylose ratio on the material properties was investigated. Compression molded films with one molar substitution of butyl glycidyl ether (BGE) showed markedly different tensile behaviors. Films made from low arabinose AX were less ductile, while those made from high arabinose AX exhibited elastomer-like behaviors. X-ray scattering confirmed the presence of nanostructure formation resulting in nano-domains rich in either AX or BGE, from side chain grafting. The scattering data showed variations in the presence of ordered structures, nano-domain sizes and their temperature response between AX with different arabinose contents. In dynamic mechanical testing, three transitions were observed at approximately −90 °C, −50 °C and 80 °C, with a correlation between samples with more structured nano-domains and those with higher onset transition temperatures and lower storage modulus decrease. The mechanical properties of the final thermoplastic AX material can therefore be tuned by controlling the composition of the starting material.
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| 25. |
- Kompus, Kristiina, 1983-, et al.
(författare)
-
Dynamic switching between semantic and episodic memory systems
- 2009
-
Ingår i: Neuropsychologia. - : Elsevier BV. - 0028-3932 .- 1873-3514. ; 47:11, s. 2252-2260
-
Tidskriftsartikel (refereegranskat)abstract
- It has been suggested that episodic and semantic long-term memory systems interact during retrieval. Here we examined the flexibility of memory retrieval in an associative task taxing memories of different strength, assumed to differentially engage episodic and semantic memory. Healthy volunteers were pre-trained on a set of 36 face-name pairs over a 6-week period. Another set of 36 items was shown only once during the same time period. About 3 months after the training period all items were presented in a randomly intermixed order in an event-related fMRI study of face-name memory. Once presented items differentially activated anterior cingulate cortex and a right prefrontal region that previously have been associated with episodic retrieval mode. High-familiar items were associated with stronger activation of posterior cortices and a left frontal region. These findings fit a model of memory retrieval by which early processes determine, on a trial-by-trial basis, if the task can be solved by the default semantic system. If not, there is a dynamic shift to cognitive control processes that guide retrieval from episodic memory.
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| 26. |
- Krali, Olga, et al.
(författare)
-
Dna methylation signatures predict cytogenetic subtype and outcome in pediatric acute myeloid leukemia (Aml)
- 2021
-
Ingår i: Genes. - : MDPI AG. - 2073-4425. ; 12:6
-
Tidskriftsartikel (refereegranskat)abstract
- Pediatric acute myeloid leukemia (AML) is a heterogeneous disease composed of clinically relevant subtypes defined by recurrent cytogenetic aberrations. The majority of the aberrations used in risk grouping for treatment decisions are extensively studied, but still a large proportion of pediatric AML patients remain cytogenetically undefined and would therefore benefit from additional molecular investigation. As aberrant epigenetic regulation has been widely observed during leukemogenesis, we hypothesized that DNA methylation signatures could be used to predict molecular subtypes and identify signatures with prognostic impact in AML. To study genome-wide DNA methylation, we analyzed 123 diagnostic and 19 relapse AML samples on Illumina 450k DNA methylation arrays. We designed and validated DNA methylation-based classifiers for AML cytogenetic subtype, resulting in an overall test accuracy of 91%. Furthermore, we identified methylation signatures associated with outcome in t(8;21)/RUNX1-RUNX1T1, normal karyotype, and MLL/KMT2A-rearranged subgroups (p < 0.01). Overall, these results further underscore the clinical value of DNA methylation analysis in AML. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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| 27. |
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| 28. |
- Larsson, Erik, 1983, et al.
(författare)
-
The Influence of KCl and HCl on the High-Temperature Oxidation of a Fe-2.25Cr-1Mo Steel at 400 °C
- 2020
-
Ingår i: Oxidation of Metals. - : Springer Science and Business Media LLC. - 1573-4889 .- 0030-770X. ; 93:1-2, s. 29-52
-
Tidskriftsartikel (refereegranskat)abstract
- The influence of alkali- and chlorine-containing compounds on the corrosion of superheater alloys has been studied extensively. The current paper instead investigates the corrosive effects of KCl and HCl under conditions relevant to waterwall conditions. A low-alloy (Fe-2.25Cr-1Mo) steel was exposed to KCl(s), 500 vppm HCl(g) and (KCl + HCl) in the presence of 5%O2 and 20% H2O at 400 °C. The results indicate that alloy chlorination by KCl occurs by an electrochemical process, involving cathodic formation of chemisorbed KOH on the scale surface and anodic formation of solid FeCl2 at the bottom of the scale. The process is accompanied by extensive cracking and delamination of the iron oxide scale, resulting in a complex, convoluted scale morphology. Adding 500 vppm HCl to the experimental environment (KCl + HCl) initially greatly accelerated the formation of FeCl2 at the scale/alloy interface. The accelerated alloy chlorination is attributed to HCl reacting with KOH at the scale surface, causing the cathodic process to be depolarized. A rapid slowing down of the rate of chlorination and corrosion in KCl + HCl environment was observed which was attributed to the electronically insulating nature of the FeCl2 layer which forms at the bottom of the scale, disconnecting the anodic and cathodic regions.
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| 29. |
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| 30. |
- Larsson, Jenny, 1990-
(författare)
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Population-based studies of higher-level gait disorders and hydrocephalus : focused on brain ventricular morphometry and patient outcomes following shunt surgery
- 2022
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: To study gait is of great importance for the health of the aging population. Higher-level gait disorders (HLGD) are characterized by a slow, symmetrical, unsteady gait. Its cause is most often unknown. HLGD in combination with ventriculomegaly (i.e., large brain ventricles) is obligatory for the diagnosis of Idiopathic Normal pressure hydrocephalus (INPH), a syndrome that is sometimes treatable with insertion of a CSF shunt. It is therefore important to investigate the prevalence of HLGD in the population and brain morphometry in individuals with HLGD. Further, self-perceived confidence in gait and balance among patients with HLGD and INPH is unknown and important to study as slow gait velocity is associated with falls, injuries, and death. CSF shunts in INPH are associated with adverse events and little is known about epilepsy after surgery or minor and moderate adverse events such as headache and abdominal pain.Objective: In the older population investigate the prevalence of HLGD, and its association to ventriculomegaly. To investigate quality of life (QoL), depressive symptoms, and balance confidence in an HLGD population. In patients shunted for INPH, assess falls, fear of falling, balance confidence and prevalence of the possible adverse events headache, epilepsy, and abdominal pain after shunt surgery. Methods: Two population-based case-controlled cohorts were studied. In the first study, the "Ventriculomegaly and gait disturbance in the senior population in the region of Västerbotten" (VESPR) study, individuals (65-84 years) were recruited through a questionnaire (n=6467 dispatched). The final population consisted of 798 cases with gait disorders and 249 controls without gait disorders, age- and sex-matched to individuals with HLGD. All had been examined by a physician and were categorized: 1. "HLGD"; 2. "neurological gait disorder"; 3. "non-neurological gait disorder" or; 4. "no gait disorder". Participants were assessed with: the Swedish modification of the Falls-Efficacy Scale (FES(S)), the Modified Gait-Efficacy Scale (mGES), the Euro Quality of Life 5-Dimension 5-Level (EQ5D5L) instrument (EQ5D5L index and Euro Quality of life visual analogue scale (EQ VAS)) and the Geriatric depression scale 15 (GDS-15). Cases and controls had an MRI of the brain and ventricular size was measured. The second study, the "Comorbidities and vascular risk factors associated with idiopathic normal pressure hydrocephalus" (INPH-CRasH) study, consisted of 176 shunted INPH patients and 368 age- and sex-matched controls. Mean age was 74 years in INPH and 73 in controls. All had a visit to a healthcare facility. Information regarding adverse events, falls and fear of falling were gathered through a questionnaire. Additional information on diagnoses and prescribed drugs were obtained from the Swedish national patient- and drug registries. Data was compared between the groups, and before- and after surgery for INPH. Results: In the VESPR study, 87 individuals were categorized as HLGD, corresponding to a prevalence of 5.8% (95% confidence interval (CI) 4.6-7.0) in the older population. A definite cause was found in 13% (n=11) of individuals with HLGD, but ventriculomegaly was present in 63% (n=46/73, controls: 38%, n=70/184; OR 2.8 95% CI 1.6-4.9, p<0.001). HLGD had more depressive symptoms and lower quality of life (QoL), compared with individuals without gait disorder (GDS-15: 3.9±3.4 vs. 2.5±2.8, p=0.004; EQ VAS: 63±17 vs. 71±18; p<0.001; EQ5D5L index: 0.671±0.188 vs. 0.840±0.126, p<0.001). HLGD had low confidence in gait and to avoid falls compared to those without gait disorder (mGES: 60±22 vs. 74±21; p<0.001; FES(S): 93±32 vs. 111±25 p<0.001). The INPH-CRasH study revealed that patients with INPH feared falling more often (3.3±1.1) and had lower balance confidence (78±40) than controls (fear of falling: 1.6±0.9, balance confidence: 126±14; p<0.001 in both comparisons). After surgery, the proportions were reduced in INPH (p<0.001). More INPH than controls were fallers (before surgery: 67% vs. 11% OR 15.48 95% CI 9.85-24.32; after surgery: 35% vs 11% OR 4.15 95% CI 2.65-6.50, p<0.001). The proportion was reduced after surgery (p<0.001). In shunted INPH, epilepsy, antiepileptic drug (AED) treatment and headache was more common than in controls (epilepsy: 4.5% vs. 1.1% OR 4.3, 95% CI 1.3-14.6, p=0.023; AED treatment: 14.8% vs. 7.3% OR 0.5 95% CI 0.3-0.8, p=0.010; headache: 36.1% vs 11.6% OR 0.2 95% CI 0.2-0.4, p<0.001). Forty percent INPH (n=70) had abdominal pain after surgery. Conclusions: HLGD was common in the general older population and associated to ventriculomegaly. HLGD was also associated with low quality of life and depressive symptoms. Both individuals with HLGD and patients with INPH had low confidence in their balance but it was less common after surgery for INPH. However, patients shunted for INPH still had more problems with low balance confidence, falls, and fear of falling than controls. After shunt surgery for INPH, a significant portion of patients developed epilepsy, headache, and abdominal pain. The findings motivate investigations of causal relationships between HLGD and ventriculomegaly and if treatment options exist for HLGD. The observed adverse events in patients shunted for INPH should be considered in pre- and postoperative evaluations of shunt surgery, and in the development of new techniques for shunt placement. Additional interventions directed towards low balance confidence, falls and fear of falling should be considered for patients with INPH, and for individuals with HLGD.
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| 31. |
- Larsson, Lars, 1983-, et al.
(författare)
-
Adaptive and Application-agnostic Caching in Service Meshes for Resilient Cloud Applications
- 2021
-
Ingår i: Proceedings of the 2021 IEEE Conference on Network Softwarization (NetSoft) : Accelerating Network Softwarization in the Cognitive Age - Accelerating Network Softwarization in the Cognitive Age. - : IEEE. - 9781665405225 ; , s. 176-180
-
Konferensbidrag (refereegranskat)abstract
- Service meshes factor out code dealing with inter-micro-service communication. The overall resilience of a cloud application is improved if constituent micro-services return stale data, instead of no data at all. This paper proposes and implements application agnostic caching for micro services. While caching is widely employed for serving web service traffic, its usage in inter-micro-service communication is lacking. Micro-services responses are highly dynamic, which requires carefully choosing adaptive time-to-life caching algorithms. Our approach is application agnostic, is cloud native, and supports gRPC. We evaluate our approach and implementation using the micro-service benchmark by Google Cloud called Hipster Shop. Our approach results in caching of about 80% of requests. Results show the feasibility and efficiency of our approach, which encourages implementing caching in service meshes. Additionally, we make the code, experiments, and data publicly available.
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| 32. |
- Larsson, Lars, 1983-, et al.
(författare)
-
Decentralized Kubernetes Federation Control Plane
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This position paper presents our vision for a distributed decentralized Kubernetes federation control plane. The goal is to support federations consisting of thousands of Kubernetes clusters, in order to support next generation edge cloud use-cases. Our review of the literature and experience with the current centralized state of the art Kubernetes federation controllers shows that it is unable to scale to a sufficient size, and centralization constitutes an unacceptable single point of failure. Our proposed system maintains cluster autonomy, allows clusters to collaboratively handle error conditions, and scales to support edge cloud use-cases. Our approach is based on a shared database of conflict-free replicated data types (CRDTs), shared among all clusters in the federation, and algorithms that make use of the data.
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| 33. |
- Larsson, Lars, 1983-, et al.
(författare)
-
Decentralized Kubernetes Federation Control Plane
- 2020
-
Ingår i: 2020 IEEE/ACM 13TH INTERNATIONAL CONFERENCE ON UTILITY AND CLOUD COMPUTING (UCC 2020). - : IEEE. - 9780738123943 ; , s. 354-359
-
Konferensbidrag (refereegranskat)abstract
- This position paper presents our vision for a distributed decentralized Kubernetes federation control plane. The goal is to support federations consisting of thousands of Kubernetes clusters, in order to support next generation edge cloud use-cases. Our review of the literature and experience with the current centralized state of the art Kubernetes federation controllers shows that it is unable to scale to a sufficient size, and centralization constitutes an unacceptable single point of failure. Our proposed system maintains cluster autonomy, allows clusters to collaboratively handle error conditions, and scales to support edge cloud use-cases. Our approach is based on a shared database of conflict-free replicated data types (CRDTs), shared among all clusters in the federation, and algorithms that make use of the data.
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| 34. |
- Larsson, Lars, 1983-, et al.
(författare)
-
Impact of etcd deployment on Kubernetes, Istio, and application performance
- 2020
-
Ingår i: Software, practice & experience. - : John Wiley & Sons. - 0038-0644 .- 1097-024X. ; 50:10, s. 1986-2007
-
Tidskriftsartikel (refereegranskat)abstract
- This experience article describes lessons learned as we conducted experiments in a Kubernetes-based environment, the most notable of which was that the performance of both the Kubernetes control plane and the deployed application depends strongly and in unexpected ways on the performance of the etcd database. The article contains (a) detailed descriptions of how networking with and without Istio works in Kubernetes, based on the Flannel Container Networking Interface (CNI) provider in VXLAN mode with IP Virtual Server (IPVS)-backed Kubernetes Services, (b) a comprehensive discussion about how to conduct load and performance testing using a closed-loop workload generator, and (c) an open source experiment framework useful for executing experiments in a shared cloud environment and exploring the resulting data. It also shows that statistical analysis may reveal the data resulting from such experiments to be misleading even when careful preparations are made, and that nondeterministic behavior stemming from etcd can affect both the platform as a whole and the deployed application. Finally, it is demonstrated that using high-performance backing storage for etcd can reduce the occurrence of such nondeterministic behaviors by a statistically significant (P < .05) margin. The implication of this experience article is that systems researchers studying the performance of applications deployed on Kubernetes cannot simply consider their specific application to be under test. Instead, the particularities of the underlying Kubernetes and cloud platform must be taken into account, in particular because their performance can impact that of etcd.
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| 35. |
- Larsson, Lars, 1983-
(författare)
-
Managing cloud resource scarcity
- 2020
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- According to the Infrastructure-as-a-Service conceptualization of cloud computing, Infrastructure Providers offer utility-like pay-as-you-go access to computing resources (e.g., data processing, networks, and storage) to Service Providers, who use those resources to host applications for the benefit of end users. The quantity of resources available to Infrastructure Providers at any given moment is limited, as is the quantity of resources allocated to the applications of each Service Provider.This thesis examines the management of cloud resource scarcity from the perspectives of both Infrastructure and Service Providers, with the aim of finding ways to ensure that the end user experience is minimally affected.We consider three main strategies for managing cloud resource scarcity. First, we explore ways to efficiently construct collaborative federations of autonomous and independent Infrastructure Providers that allow local resource scarcity to be masked by extension using capacity from remote sites. Second, we consider how scheduling both within a cloud site and across a federation can be made aware of restrictions imposed by Service Providers for, e.g., performance or legal reasons. Third, we suggest ways of making applications conscious of resource availability so that they can apply quality elasticity under resource constraints.The thesis is the culmination of 11 years of work within academia and industry. Based on the unique perspective granted by this long experience, the introductory chapters present a historical view of each subtopic mentioned above. Specifically, they discuss how cloud computing has evolved in conjunction with ways of developing applications to the symbiotic benefit of both, leading to the emergence of cloud-native software that allows Infrastructure Providers to use their infrastructure more efficiently and offer it more affordably while simultaneously granting Service Providers improved availability and performance in cloud-based environments.
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| 36. |
- Larsson, Lars, 1983-
(författare)
-
Placement and Monitoring of Orchestrated Cloud Services
- 2015
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cloud computing offers pay-per-use on-demand access to computer resources for hosting program execution environments for software service deployment. Management of cloud resources includes determining, based on current monitored resource availability, which part(s) of a computational infrastructure should host such program execution environments in a process called placement. Our work defines directives that lets consumers of cloud resources influence placement to express relationships between cloud services (orchestration) and deployment constraints to uphold for related service components, without surrendering the ultimate control over placement from the infrastructure owner. The infrastructure owner remains free to define their policies and placement optimization criteria, e.g., to consolidate work that needs to be done to as few physical host machines as possible for power savings reasons. We show how the placement process can be adjusted to take such influence into account and validate through simulations that the adjustments produce the correct result without too large computational impact on the placement process itself. Further, we present a technique for transferring large data files between cloud data centers that operate in (separate) cloud federations that avoids repeated transfers in a delegation chain between members of (different) cloud federations. Finally, we present a non-invasive method of extracting monitoring data from a service deployed in a cloud federation, and a framework for making monitoring information available and understandable in spite of technical differences between monitoring systems used in cloud federations.
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| 37. |
- Larsson, Lars, 1983-, et al.
(författare)
-
Quality-Elasticity: Improved Resource Utilization, Throughput, and Response Times Via Adjusting Output Quality to Current Operating Conditions
- 2019
-
Ingår i: IEEE International Conference on Autonomic Computing (ICAC). - : IEEE. - 9781728124124 - 9781728124117
-
Konferensbidrag (refereegranskat)abstract
- This work addresses two related problems for on-line services, namely poor resource utilization during regular operating conditions, and low throughput, long response times, or poor performance under periods of high system load. To address these problems, we introduce our notion of quality-elasticity as a manner of dynamically adapting response qualities from software services along a fine-grained spectrum. When resources are abundant, response quality can be increased, and when resources are scarce, responses are delivered at a lower quality to prioritize throughput and response times. We present an example of how a complex online shopping site can be made quality-elastic. Experiments show that, compared to state of the art, improvements in throughput (57% more served queries), lowered response times (8 time reduction for 95th percentile responses), and an estimated 40% profitability increase can be made using our quality-elastic approach. When resources are abundant, our approach may achieve upwards of twice as high resource utilization as prior work in this field.
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| 38. |
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| 39. |
- Larsson, Måns, 1989, et al.
(författare)
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A cross-season correspondence dataset for robust semantic segmentation
- 2019
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Ingår i: Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition. - 1063-6919. ; 2019-June, s. 9524-9534
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we present a method to utilize 2D-2D point matches between images taken during different image conditions to train a convolutional neural network for semantic segmentation. Enforcing label consistency across the matches makes the final segmentation algorithm robust to seasonal changes. We describe how these 2D-2D matches can be generated with little human interaction by geometrically matching points from 3D models built from images. Two cross-season correspondence datasets are created providing 2D-2D matches across seasonal changes as well as from day to night. The datasets are made publicly available to facilitate further research. We show that adding the correspondences as extra supervision during training improves the segmentation performance of the convolutional neural network, making it more robust to seasonal changes and weather conditions.
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| 40. |
- Larsson, Måns, 1989, et al.
(författare)
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Fine-Grained Segmentation Networks: Self-Supervised Segmentation for Improved Long-Term Visual Localization
- 2019
-
Ingår i: Proceedings of the IEEE International Conference on Computer Vision. - 1550-5499. ; :October, s. 31-41
-
Konferensbidrag (refereegranskat)abstract
- Long-term visual localization is the problem of estimating the camera pose of a given query image in a scene whose appearance changes over time. It is an important problem in practice, for example, encountered in autonomous driving. In order to gain robustness to such changes, long-term localization approaches often use segmantic segmentations as an invariant scene representation, as the semantic meaning of each scene part should not be affected by seasonal and other changes. However, these representations are typically not very discriminative due to the limited number of available classes. In this paper, we propose a new neural network, the Fine-Grained Segmentation Network (FGSN), that can be used to provide image segmentations with a larger number of labels and can be trained in a self-supervised fashion. In addition, we show how FGSNs can be trained to output consistent labels across seasonal changes. We demonstrate through extensive experiments that integrating the fine-grained segmentations produced by our FGSNs into existing localization algorithms leads to substantial improvements in localization performance.
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| 41. |
- Larsson, Malin, 1983-
(författare)
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Toward increased applicability of ultrasound contrast agents
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ultrasound is one of the most widely used modalities in medical imaging because of its high cost-effectiveness, wide availability in hospitals, generation of real-time images, and use of nonionizing radiation. However, the image quality can be insufficient in some patients. Introducing a contrast agent (CA), which comprises a suspension of 2–6 mm-sized microbubbles, improves the image quality and thus the image analysis. At present, contrast-enhanced ultrasound is frequently used during standard clinical procedures such as kidney, liver, and cardiac (echocardiography) imaging. Multimodality and targeted imaging are future areas for ultrasound CAs. Multimodality imaging may improve diagnostics by simultaneously providing anatomical and functional information. Targeted imaging may allow for identification of particular diseases.The work within this thesis focused mainly on a novel multimodal polymer-shelled CA with the potential to be target specific. In Study I, the acoustic response was determined in a flow phantom by evaluating the contrast-to-tissue-ratio when using contrast sequences available in clinical ultrasound systems. This study showed that a high acoustic pressure is needed for optimal visualization of the polymer-shelled CA. In Study II, the in vivo performance of this CA was evaluated in a rat model, and the blood elimination time and subcellular distribution were determined. In Study III, the efficiency in endocardial border delineation was assessed in a pig model. The polymer-shelled CA had a significantly longer blood circulation time than the commercially available CA SonoVue, which is favorable for target-specific CA, in which a long circulation time increases the probability of target-specific binding. Transmission electron microscopic analysis of tissue sections from liver, kidney, spleen and lungs, obtained at different time points after CA injection showed that macrophages were responsible for the elimination of the polymer-shelled CA. A higher dose of the polymer-shelled CA was needed to obtain similar endocardial border delineation efficiency as that obtained using SonoVue. The results of Studies I–III demonstrate that the polymer-shelled CA has potential applicability in medical imaging.Current guidelines for contrast-enhanced echocardiography are limited to cases of suboptimal image quality or when there is a suspicion of structural abnormalities within the left ventricle. It may be hypothesized that the wider use of contrast-enhanced echocardiography may help to detect some diseases earlier. Study IV assessed the diagnostic outcomes after contrast administration in patients without indications for CA use. The myocardial wall motion score index and ejection fraction were evaluated by experienced and inexperienced readers, and a screening for left ventricular structural abnormalities was performed. More cases of wall motion and structural abnormalities were detected in the contrast-enhanced analysis. Intra- and interobserver variability was lower with the use of CAs. This study suggests that the more widespread use of CAs instead of the current selective approach may contribute to earlier detection of cardiovascular disease.
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| 42. |
- Larsson Tholén, Susanna, 1967-, et al.
(författare)
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Economic Evaluation of Supported-Employment Inspired Program for Pupils With Intellectual Disabilities
- 2017
-
Ingår i: Nordic Journal of Working Life Studies. - : Roskilde University. - 2245-0157. ; 7:1, s. 69-86
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, we investigate whether, or to what degree, a ‘business case’ could be made for implementation of a Supported-Employment (SE) inspired program for pupils with intellectual disabilities (IDs), starting during the final school years. For this aim, we do a quasi-experimental before-after intervention impact evaluation of such a project funded by the European Social Fund in the Swedish city of Örebro (135,000 inhabitants) during 2010–2013. From an estimate of the average treatment effect, we calculate the internal net present value and the payback period that would make this program break even from avoided expenditure for day-activity services, assuming that it had been funded entirely by the municipality.
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| 43. |
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| 44. |
- Lo Re, Giada, PhD, 1971-, et al.
(författare)
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Poly(ϵ-caprolactone) Biocomposites Based on Acetylated Cellulose Fibers and Wet Compounding for Improved Mechanical Performance
- 2018
-
Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 6:5, s. 6753-6760
-
Tidskriftsartikel (refereegranskat)abstract
- Poly(ϵ-caprolactone) (PCL) is a ductile thermoplastic, which is biodegradable in the marine environment. Limitations include low strength, petroleum-based origin, and comparably high cost. Cellulose fiber reinforcement is therefore of interest although uniform fiber dispersion is a challenge. In this study, a one-step wet compounding is proposed to validate a sustainable and feasible method to improve the dispersion of the cellulose fibers in hydrophobic polymer matrix as PCL, which showed to be insensitive to the presence of the water during the processing. A comparison between unmodified and acetylated cellulosic wood fibers is made to further assess the net effect of the wet feeding and chemical modification on the biocomposites properties, and the influence of acetylation on fiber structure is reported (ATR-FTIR, XRD). Effects of processing on nanofibrillation, shortening, and dispersion of the cellulose fibers are assessed as well as on PCL molar mass. Mechanical testing, dynamic mechanical thermal analysis, FE-SEM, and X-ray tomography is used to characterize composites. With the addition of 20 wt % cellulosic fibers, the Young's modulus increased from 240 MPa (neat PCL) to 1850 MPa for the biocomposites produced by using the wet feeding strategy, compared to 690 MPa showed for the biocomposites produced using dry feeling. A wet feeding of acetylated cellulosic fibers allowed even a greater increase, with an additional 46% and 248% increase of the ultimate strength and Young's modulus, when compared to wet feeding of the unmodified pulp, respectively.
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| 45. |
- Nilton, Anna, et al.
(författare)
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Zinc Finger Protein 148 Is Dispensable for Primitive and Definitive Hematopoiesis in Mice
- 2013
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:7
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Tidskriftsartikel (refereegranskat)abstract
- Hematopoiesis is regulated by transcription factors that induce cell fate and differentiation in hematopoietic stem cells into fully differentiated hematopoietic cell types. The transcription factor zinc finger protein 148 (Zfp148) interacts with the hematopoietic transcription factor Gata1 and has been implicated to play an important role in primitive and definitive hematopoiesis in zebra fish and mouse chimeras. We have recently created a gene-trap knockout mouse model deficient for Zfp148, opening up for analyses of hematopoiesis in a conventional loss-of-function model in vivo. Here, we show that Zfp148-deficient neonatal and adult mice have normal or slightly increased levels of hemoglobin, hematocrit, platelets and white blood cells, compared to wild type controls. Hematopoietic lineages in bone marrow, thymus and spleen from Zfp148(gt/gt) mice were further investigated by flow cytometry. There were no differences in T-cells (CD4 and CD8 single positive cells, CD4 and CD8 double negative/positive cells) in either organ. However, the fraction of CD69- and B220-positive cells among lymphocytes in spleen was slightly lower at postnatal day 14 in Zfp148(gt/gt) mice compared to wild type mice. Our results demonstrate that Zfp148-deficient mice generate normal mature hematopoietic populations thus challenging earlier studies indicating that Zfp148 plays a critical role during hematopoietic development.
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| 46. |
- Peciulyte, Ausra, 1986, et al.
(författare)
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Cellulolytic enzyme interaction with lignocellulose. Insight to factors limiting enzymatic hydrolysis
- 2013
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Ingår i: Gordon Conference: Cellulosomes, Cellulases & Other Carbohydrate Modifying Enzymes internal database.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Liberation of fermentable soluble sugars from lignocellulosic biomass during the course of enzymatic hydrolysis is the major obstacle to large-scale implementation of biorefineries due to high cost of enzymes. Enzymatic hydrolysis of lignocellulosic biomass is often incomplete and, therefore, it is of great importance to understand the limitations of the process. Among the limitations of enzymatic hydrolysis, structural properties of lignocellulose have an effect of enzymatic hydrolysis efficiency. Currently, there is a lack of direct methods for visualization and quantification of spatial polymer distribution in lignocellulosic biomass and monitoring of interactions between cellulose degrading enzymes and the substrate. The focus of the work was (i) structural characterization of lignocellulose during the course of hydrolysis and (ii) to provide a more detailed understanding of cellulolytic enzyme interaction with lignocellulose. The overall aim was to understand the limitations in enzymatic hydrolysis of lignocellulosic biomass.Enzymatic hydrolysis was studied on industrial-like lignocellulosic and cellulosic substrates, resulting from alkaline pulping and steam explosion of spruce. Enzymatic hydrolysis of lignocellulosic substrates was compared to enzymatic hydrolysis of model cellulosic substrates. Enzymatic hydrolysis of the substrates was performed with commercial enzyme mixture Celluclast 1.5 L and also with designed enzyme mixtures, consisting of mono-component enzymes. The structural properties of the substrates during an incrementing time of hydrolysis were analyzed by solid-state Nuclear Magnetic Resonance (NMR) spectroscopy, Coherent Anti-Strokes Raman Scattering (CARS) and Second Harmonic Generation (SHG) microscopy. Hydrolysis products were verified by High Performance Anion Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD). Dynamics of the hydrolysis was analyzed by Quartz Crystal Microbalance with Dissipation (QCM-D) technique.
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| 47. |
- Rochwerger, Benny, et al.
(författare)
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An architecture for federated cloud computing
- 2011
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Ingår i: Cloud computing. - Hoboken, N. J. : John Wiley & Sons. - 9780470887998 - 9780470940105 ; , s. 393-412
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Bokkapitel (refereegranskat)
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| 48. |
- Salmasi, Armin, 1983-
(författare)
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ICME guided study of mass transport in production and application of cemented carbides
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cemented carbides are metallic composites consisting of a WC hard phase and a ductile binder, usually Co-based, produced by powder metallurgy and sintering. Cemented carbides are an essential part of modern material and manufacturing processes. However, Co powder is classified as a carcinogenic material with serious health hazards, and most virgin Co reservoirs are located in conflict regions. In addition, there are monopolies in the market for pure tungsten. Therefore, reducing the consumption of cobalt or replacing it with other non-hazardous elements would increase the sustainability of cemented carbide production. Furthermore, advances in production technology can help overcome raw material limitations. One such advancement is non-homogeneous structures and properties for optimization of microstructure which is the topic of this thesis. Integrated computational materials engineering (ICME) and its complementary tools, calculation of phase diagram (CALPHAD), and ab-initio modeling are strong tools that bridge experimentation and modeling. In this thesis, a framework for the material design of non-homogeneous cemented carbides is proposed and tested using these computational tools. The workflow of the material design of non-homogeneous microstructure and properties were studied on different length scales. Atomistic modeling with density functional theory (DFT), ab-initio molecular dynamics (AIMD), and generalized hydrodynamics (GHD) were used to model the viscosity of liquid Co binder. In addition, the mobility of Ti and Fe in disordered BCC TiFe alloy was assessed using new experimental data from the diffusion couple experiments and an electron probe micro-analyzer (EPMA). These two studies were conducted to complete the data necessary to study cemented carbides’ processing and performance. The other studied phenomenon studied by experimentation and modeling is the formation of the gradient zone and the γ cone structure. In addition, a phenomenological model for liquid phase migration (LPM) was created and implemented using the homogenization approach. The LPM pro- cess was studied experimentally and modeled with the YAPFI software. A study of these performers was necessary to link processing and microstructure. On the performance side, the chemical interaction between cutting tools and Ti alloys was studied in detail through experimentation and modeling of diffusion. In addition, hardness and toughness models were applied to predict the longevity of studied cemented carbides. Finally, by applying ICME and material design, a high entropy alloy (HEA) alternative to Co binder was designed, produced, and tested. The research presented in this dissertation attempts to fill the gaps in the material design workflow of cemented carbides by developing new tools and methods based on ICME and CALPHAD paradigms. This goal is achieved by studying different length scales, processing methods, microstructure, properties, and performance of cemented carbides.
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| 49. |
- Tran, Pham Tue Hung, 1991-, et al.
(författare)
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Development of a Multivalent Kunjin Virus Reporter Virus-Like Particle System Inducing Seroconversion for Ebola and West Nile Virus Proteins in Mice
- 2020
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Ingår i: Microorganisms. - Basel, Switzerland : MDPI. - 2076-2607. ; 8:12
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Tidskriftsartikel (refereegranskat)abstract
- Kunjin virus (KUNV) is an attenuated strain of the severe neurotropic West Nile virus (WNV). The virus has a single-strand positive-sense RNA genome that encodes a polyprotein. Following gene expression, the polyprotein is cleaved into structural proteins for viral packaging and nonstructural proteins for viral replication and expression. Removal of the structural genes generate subgenomic replicons that maintain replication capacity. Co-expression of these replicons with the viral structural genes produces reporter virus-like particles (RVPs) which infect cells in a single round. In this study, we aimed to develop a system to generate multivalent RVPs based on KUNV to elicit an immune response against different viruses. We selected the Ebola virus (EBOV) glycoprotein (GP) and the matrix protein (VP40) genes, as candidates to be delivered by KUNV RVPs. Initially, we enhanced the production of KUNV RVPs by generating a stable cell line expressing the KUNV packaging system comprising capsid, precursor membrane, and envelope. Transfection of the DNA-based KUNV replicon into this cell line resulted in an enhanced RVP production. The replicon was expressed in the stable cell line to produce the RVPs that allowed the delivery of EBOV GP and VP40 genes into other cells. Finally, we immunized BALB/cN mice with RVPs, resulting in seroconversion for EBOV GP, EBOV VP40, WNV nonstructural protein 1, and WNV E protein. Thus, our study shows that KUNV RVPs may function as a WNV vaccine candidate and RVPs can be used as a gene delivery system in the development of future EBOV vaccines.
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| 50. |
- Wallner, Lars, 1983-, et al.
(författare)
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Students’ Constructions of Professional Judgement in Teacher Education, Medical Education and Police Education
- 2024
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Ingår i: Högre Utbildning. - 2000-7558. ; 14:1, s. 49-63
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Tidskriftsartikel (refereegranskat)abstract
- Vocational training programmes in higher education encompass, as learning objectives, the development of relational skills and professional judgement, especially in welfare professions such as policing, teaching and healthcare, where know-how about managing close contact with people is a prerequisite. Based on a cross-professional analysis, the current article explores how students from three different professional education programmes – teacher education, police training and medical education – construct professional judgement in group discussions and interviews. The results show that participants construct professional judgement as relationships between three different dimensions: personal ethics, educational standards, and professional practice. When discussing professional dilemmas, students utilise these three different dimensions to argue for the moral or ethical soundness of their choices. The results of the study shed light on the importance of providing students with opportunities to reflect openly on professional judgement in different ways, even though such reflections may not always be formally assessed. Furthermore, the analysis demonstrates similarities between the three programmes that we analysed, as well as similarities in students’ reflections regarding essential aspects of the professions.
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