| 1. |
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| 2. |
- Akerlind, C, et al.
(author)
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Optical properties and switching of a Rose Bengal derivative: A spectroscopic ellipsometry study
- 2011
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In: THIN SOLID FILMS. - : Elsevier Science B.V., Amsterdam.. - 0040-6090. ; 519:11, s. 3582-3586
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Journal article (peer-reviewed)abstract
- Optical properties in terms of the complex-valued dielectric function were determined for spin-coated films of a Rose Bengal derivative using variable angle of incidence spectroscopic ellipsometry in the visible and infrared wavelength regions. In addition, the thickness and roughness of the films were determined and related to the solution concentration of Rose Bengal. Switching between two different oxidation states of the Rose Bengal derivative was investigated. The two states were chemically induced by exposure to vapors of hydrochloric acid and ammonia, respectively. A substantial and reversible change of the optical properties of the films was observed.
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| 3. |
- Andersson, A. F., et al.
(author)
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Comparative analysis of human gut microbiota by barcoded pyrosequencing
- 2008
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 3:7
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Journal article (peer-reviewed)abstract
- Humans host complex microbial communities believed to contribute to health maintenance and, when in imbalance, to the development of diseases. Determining the microbial composition in patients and healthy controls may thus provide novel therapeutic targets. For this purpose, high-throughput, cost-effective methods for microbiota characterization are needed. We have employed 454-pyrosequencing of a hyper-variable region of the 16S rRNA gene in combination with sample-specific barcode sequences which enables parallel in-depth analysis of hundreds of samples with limited sample processing. In silico modeling demonstrated that the method correctly describes microbial communities down to phylotypes below the genus level. Here we applied the technique to analyze microbial communities in throat, stomach and fecal samples. Our results demonstrate the applicability of barcoded pyrosequencing as a high-throughput method for comparative microbial ecology.
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| 4. |
- Andersson, Björn O, 1982, et al.
(author)
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A Modified TAB Model for Simulation of Atomization in Rotary Bell Spray Painting
- 2013
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In: Journal of Mechanical Engineering and Automation. - 2163-2413. ; 3:2, s. 54-61
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Journal article (peer-reviewed)abstract
- The Rotary bell spray applicator technique is commonly used in the automotive industry for paint application because of its high transfer efficiency and high-quality result. The bell spins rapidly around its axis with a tangential velocity at the edge in the order of 100 m/s. The paint falls off the edge and enters the air with a large relative velocity, driving the atomization into small droplets where the resulting size distribution depends on the process conditions. Especially the rotation speed of the bell is an important parameter governing the size distribution. The main research question in this work is to investigate if the Taylor Analogy Breakup (TAB) model can be used to predict the resulting droplet size distributions in spray painting. As the paint is a viscous fluid a modification of the TAB model taking non-linear effects of large viscosity into account is proposed. The parameters in the breakup model are tuned by optimization to match droplet size distributions obtained in CFD simulations with measured ones. Results are presented for three cases with rotation speeds from 30 to 50 thousand RPM where the full droplet size distributions are compared with measurements. Good results are obtained for all three cases where the simulated size distributions compare well to measurements over a wide range of droplet sizes. The TAB method is able to quantitatively predict the result of the breakup process and can be used in a preprocessing stage of a full spray painting simulation, thereby reducing the need for costly and cumbersome measurements.
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| 5. |
- Andersson, Björn O, 1982, et al.
(author)
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Modeling Surface Tension in SPH by Interface Reconstruction using Radial Basis Functions
- 2010
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In: Proceedings of the 5th International SPHERIC Workshop, 22-25 June 2010, Manchester, U.K., edited by B. D. Rogers. ; , s. 7-14
-
Conference paper (other academic/artistic)abstract
- A novel method for reconstructing the interface between two fluids is described and evaluated. The method uses a different basis for approximating the color function than what is common practice in SPH simulations. The key feature of the new method is the ability to omit small length scale structures in order to obtain a smoother representation. A smoother interface is more suitable to derive a surface tension force from, as the magnitude of the force is proportional to the curvature which is related to the second derivative along the interface.
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| 6. |
- Andersson, Björn O, 1982, et al.
(author)
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Modified TAB Model for Viscous Fluids applied to Breakup in Rotary Bell Spray Painting
- 2012
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In: ICLASS 2012 - 12th International Conference on Liquid Atomization and Spray Systems.
-
Conference paper (peer-reviewed)abstract
- The Taylor Analogy Breakup (TAB) model is applied to droplet breakup in rotary bell spray painting commonly used in the automotive industry. The bell spins rapidly around its axis with a tangential velocity at the edge in the order of 100 m/s. The paint falls off the edge and enters the air with a large relative velocity, driving the atomization. The paint is a viscous fluid and a modification of the TAB model taking non-linear effects of large viscosity into account is described. The parameters in the breakup model are tuned to match droplet size distributions obtained in CFD simulations with measured ones. Results are presented for three cases with rotation speeds from 30 to 50 thousand RPM where the full droplet size distributions are compared with measurements. Good results are obtained for all three cases where the simulated size distributions compare well to measurements over a wide range of droplet sizes. The obtained results can be used in a preprocessing stage of a full spray painting simulation thereby reducing the need for costly and cumbersome measurements.
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| 7. |
- Andersson, Christina, 1955, et al.
(author)
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Drinking context and problematic alcohol consumption in young Swedish women : Drinking context and problematic alcohol consumption
- 2013
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In: Addiction Research and Theory. - : Informa UK Limited. - 1606-6359 .- 1476-7392. ; 21:6, s. 457-468
-
Journal article (peer-reviewed)abstract
- Previous research has indicated that a variety of contextual factors are involved in the development of drinking behavior. An integrated perspective can extend our understanding of the context and circumstances in which individuals drink. In this study, a person-oriented approach, cluster analysis, was used to identify drinking context clusters in a population of 20- and 25-year-old Swedish women. A further aim was to analyze how these clusters were associated with problematic alcohol consumption (high episodic drinking (HED) and alcohol use disorder (AUD)). A total of 760 respondents were interviewed, some in 1996 and some in 2001. Self-reported effects of drinking and situational factors associated with drinking alcohol were used in the cluster analysis procedure. Logistic regression models were used to analyze the associations with problematic alcohol consumption. The results revealed four distinct clusters of drinking patterns: coping drinkers, social drinkers, controlled drinkers, and moderate drinkers. Differences between clusters concerning problematic alcohol consumption were found. HED was significantly more common among the social drinkers and alcohol use disorder was more prevalent among the coping drinkers. Age differences and to a lesser extent secular trends in drinking pattern could be observed. The findings suggest that information on drinking context can help to explain differences in patterns of risky drinking and AUD. This highlights the importance of identifying groups of individuals with potentially harmful drinking patterns, which could be the target of specific preventive actions.
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| 8. |
- Andersson, Christina, 1955, et al.
(author)
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Dryckeskontextens betydelse för unga kvinnors alkoholkonsumtion. En klusteranalys av 20- och 25-åriga kvinnor åren 1995 och 2000.
- 2008
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In: Läkarstämman, Göteborg 2008.
-
Conference paper (other academic/artistic)abstract
- Dryckeskontextens betydelse för unga kvinnors alkoholkonsumtion. En klusteranalys av 20- och 25-åriga kvinnor åren 1995 och 2000. Bakgrund Under de senaste åren har framför allt en del internationell drogforskning fokuserat på fenomen som dryckeskontext och egna motiv till att dricka samt dessas samband med alkoholkonsumtion. Dryckeskontext har i nämnda studier definierats på något olika sätt, några mer teoretiskt förankrade, gemensamt kan sägas att man försökt besvara frågor om var, med vem och varför man druckit alkohol I den aktuella studien har vi analyserat sambandet mellan dryckeskontext och alkoholkonsumtion bland 20- och 25-åriga kvinnor i Göteborg. Syftet var att undersöka om det fanns specifika dryckesmönster, med hänsyftning på kontextuella variabler, om dessa dryckesmönster skiljde sig åt mellan undersökningsåren och om vissa dryckesmönster visade starkare samband med olika grader av alkoholkonsumtion. Metod Data från en befolkningsundersökning, ”Kvinnor och alkohol i Göteborg”: I studien ingick 897 unga kvinnor intervjuade under åren 1995 och 2000. Då dryckeskontext kan ses som ett multifaktoriellt fenomen valde vi att använda klusteranalys (”Two-step clustering”) för att identifiera grupper med olika dryckesmönster. Vi använde Pearson Chi-square för att undersöka skillnader i alkoholkonsumtion mellan de olika grupperna. Alkoholkonsumtion fördelades som Alkoholmissbruk/beroende - ABM, Intensivkonsumtion (60g etanol/tillfälle) - IK, Intensivkonsumtion/12 mån. – IK12 och Hög alkoholkonsumtion (20g etanol/dag senaste månaden) - HAK. Resultat Med hjälp av klusteranalys identifierades tre grupper med olika dryckesmönster för varje undersökningsår. 1995 syntes en grupp måttlighetsdrickare, en grupp som drack ofta både i sociala sammanhang och i ensamhet samt en grupp som bejakade mest upplevda effekter av sitt drickande. 2000 fann vi åter gruppen måttlighetsdrickare, därtill en grupp där man bejakade sociala effekter av alkohol och en annan grupp som uppgav mer fysiska och kognitiva effekter. 1995 visade gruppen som drack i ofta i sociala sammanhang signifikanta samband med ABM, IK12 och HAK. År 2000 sågs signifikanta samband med alla konsumtionsvariablerna hos de båda grupper som bejakande olika upplevda effekter av alkoholanvändning. Sammanfattning Klusteranalys var en god metod för att identifiera grupper med olika dryckesmönster som underlag för analys av skillnader i alkoholkonsumtion. Analysen understryker vikten av att ta hänsyn till upplevda effekter av och egna anledningar till drickande när man vill medverka till en minskad alkoholkonsumtion i befolkningen.
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| 9. |
- Andersson, Mattias, et al.
(author)
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Intrinsic and extrinsic influences on the temperature dependence of mobility in conjugated polymers
- 2008
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In: Organic electronics. - : Elsevier. - 1566-1199 .- 1878-5530. ; 9:5, s. 569-574
-
Journal article (peer-reviewed)abstract
- The temperature dependence of charge carrier mobility in conjugated polymers and their blends with fullerenes is investigated with different electrical methods, through field effect transistor (FET), space charge limited current (SCLC) and charge extraction (CELIV) measurements. Simple models, such as the Gaussian disorder model (GDM), are shown to accurately predict the temperature behavior, and a good correlation between the different measurement methods is obtained. Inconsistent charge carrier concentrations in the modeling are explained through intrinsic non-equilibrium effects, and are responsible for the limited applicability of existing numerical models. A severe extrinsic influence from water in FETs with a hydrophilic insulator interface is also demonstrated. The presence of water leads to a significant overestimate of the disorder in the materials from measurements close to room temperature and erratic behavior in the 150-350 K range. To circumvent this problem it is shown to be necessary to measure under ultra high vacuum (UHV) conditions. © 2008 Elsevier B.V. All rights reserved.
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| 10. |
- Austeng, Dordi, et al.
(author)
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Incidence of and risk factors for neonatal morbidity after active perinatal care : extremely preterm infants study in Sweden (EXPRESS)
- 2010
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In: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 99:7, s. 978-992
-
Journal article (peer-reviewed)abstract
- Aims: The aim of this study was to determine the incidence of neonatal morbidity in extremely preterm infants and to identify associated risk factors. Methods: Population based study of infants born before 27 gestational weeks and admitted for neonatal intensive care in Sweden during 2004-2007. Results: Of 638 admitted infants, 141 died. Among these, life support was withdrawn in 55 infants because of anticipation of poor long-term outcome. Of 497 surviving infants, 10% developed severe intraventricular haemorrhage (IVH), 5.7% cystic periventricular leucomalacia (cPVL), 41% septicaemia and 5.8% necrotizing enterocolitis (NEC); 61% had patent ductus arteriosus (PDA) and 34% developed retinopathy of prematurity (ROP) stage >= 3. Eighty-five per cent needed mechanical ventilation and 25% developed severe bronchopulmonary dysplasia (BPD). Forty-seven per cent survived to one year of age without any severe IVH, cPVL, severe ROP, severe BPD or NEC. Tocolysis increased and prolonged mechanical ventilation decreased the chances of survival without these morbidities. Maternal smoking and higher gestational duration were associated with lower risk of severe ROP, whereas PDA and poor growth increased this risk. Conclusion: Half of the infants surviving extremely preterm birth suffered from severe neonatal morbidities. Studies on how to reduce these morbidities and on the long-term health of survivors are warranted.
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| 11. |
- Bergman, JP, et al.
(author)
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Characterisation and defects in silicon carbide
- 2002
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In: Materials Science Forum, Vols. 389-393.
-
Conference paper (peer-reviewed)abstract
- In this work we present experimental results of several defects in 4H Sic that are of interest both from a fundamental and physical point of view. And also of great importance for device applications utilizing the Sic material. These defects include the temperature stable so called D1 defect, which is created after irradiation. This optical emission has been identified as an isoelectronic defect bound at a hole attractive pseudodonor, and we have been able to correlate this to the electrically observed hole trap HS1 seen in minority carrier transient spectroscopy (MCTS). It also includes the UD1 defect observed using absorption and FTIR and which is believed to be responsible for the semi-insulating behavior of material grown by the High temperature, HTCVD technique. Finally, we have described the formation and proper-ties of critical, generated defect in high power Sic bipolar devices. This is identified as a stacking fault in the Sic basal plane, using mainly white beam synchrotron Xray topography. The stacking fault is both optically and electrically active, by forming extended local potential reduction of the conduction band.
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| 12. |
- Brattwall, Metha, 1952, et al.
(author)
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Brief review: Theory and practice of minimal fresh gas flow anesthesia.
- 2012
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In: Canadian journal of anaesthesia. - : Springer Science and Business Media LLC. - 1496-8975 .- 0832-610X. ; 59:8, s. 785-797
-
Journal article (peer-reviewed)abstract
- PURPOSE: The aim of this brief review is to provide an update on the theory regarding minimal fresh gas flow techniques for inhaled general anesthesia. The article also includes an update and discussion of the practical aspects associated with minimal-flow anesthesia, including the advantages, potential limitations, and safety considerations of this important anesthetic technique. PRINCIPAL FINDINGS: Reducing the fresh gas flow to<1 L·min(-1) during maintenance of anesthesia is associated with several benefits. Enhanced preservation of temperature and humidity, cost savings through more efficient utilization of inhaled anesthetics, and environmental considerations are three key reasons to implement minimal-flow and closed-circuit anesthesia, although potential risks are hypoxic gas mixtures and inadequate depth of anesthesia. The basic elements of the related pharmacology need to be considered, especially pharmacokinetics of the inhaled anesthetics. The third-generation inhaled anesthetics, sevoflurane and desflurane, have low blood and low tissue solubility, which facilitates rapid equilibration between the alveolar and effect site (brain) concentrations and makes them ideally suited for low-flow techniques. The use of modern anesthetic machines designed for minimal-flow techniques, leak-free circle systems, highly efficient CO(2) absorbers, and the common practice of utilizing on-line real-time multi-gas monitor, including essential alarm systems, allow for safe and cost-effective minimal-flow techniques during maintenance of anesthesia. The introduction of new anesthetic machines with built-in closed-loop algorithms for the automatic control of inspired oxygen and end-tidal anesthetic concentration will further enhance the feasibility of minimal-flow techniques. CONCLUSIONS: With our modern anesthesia machines, reducing the fresh gas flow of oxygen to 0.3-0.5 L·min(-1) and using third-generation inhaled anesthetics provide a reassuringly safe anesthetic technique. This environmentally friendly practice can easily be implemented for elective anesthesia; furthermore, it will facilitate cost savings and improve temperature homeostasis.
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| 13. |
- Bridel, Claire, et al.
(author)
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Diagnostic Value of Cerebrospinal Fluid Neurofilament Light Protein in Neurology : A Systematic Review and Meta-analysis
- 2019
-
In: JAMA Neurology. - : American Medical Association (AMA). - 2168-6149 .- 2168-6157. ; 76:9, s. 1035-1048
-
Research review (peer-reviewed)abstract
- Importance Neurofilament light protein (NfL) is elevated in cerebrospinal fluid (CSF) of a number of neurological conditions compared with healthy controls (HC) and is a candidate biomarker for neuroaxonal damage. The influence of age and sex is largely unknown, and levels across neurological disorders have not been compared systematically to date.Objectives To assess the associations of age, sex, and diagnosis with NfL in CSF (cNfL) and to evaluate its potential in discriminating clinically similar conditions.Data Sources PubMed was searched for studies published between January 1, 2006, and January 1, 2016, reporting cNfL levels (using the search terms neurofilament light and cerebrospinal fluid) in neurological or psychiatric conditions and/or in HC.Study Selection Studies reporting NfL levels measured in lumbar CSF using a commercially available immunoassay, as well as age and sex.Data Extraction and Synthesis Individual-level data were requested from study authors. Generalized linear mixed-effects models were used to estimate the fixed effects of age, sex, and diagnosis on log-transformed NfL levels, with cohort of origin modeled as a random intercept.Main Outcome and Measure The cNfL levels adjusted for age and sex across diagnoses.Results Data were collected for 10 059 individuals (mean [SD] age, 59.7 [18.8] years; 54.1% female). Thirty-five diagnoses were identified, including inflammatory diseases of the central nervous system (n = 2795), dementias and predementia stages (n = 4284), parkinsonian disorders (n = 984), and HC (n = 1332). The cNfL was elevated compared with HC in a majority of neurological conditions studied. Highest levels were observed in cognitively impaired HIV-positive individuals (iHIV), amyotrophic lateral sclerosis, frontotemporal dementia (FTD), and Huntington disease. In 33.3% of diagnoses, including HC, multiple sclerosis, Alzheimer disease (AD), and Parkinson disease (PD), cNfL was higher in men than women. The cNfL increased with age in HC and a majority of neurological conditions, although the association was strongest in HC. The cNfL overlapped in most clinically similar diagnoses except for FTD and iHIV, which segregated from other dementias, and PD, which segregated from atypical parkinsonian syndromes.Conclusions and Relevance These data support the use of cNfL as a biomarker of neuroaxonal damage and indicate that age-specific and sex-specific (and in some cases disease-specific) reference values may be needed. The cNfL has potential to assist the differentiation of FTD from AD and PD from atypical parkinsonian syndromes.
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| 14. |
- Crispin, Xavier, 1972-, et al.
(author)
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The origin of the high conductivity of poly(3,4-ethylenedioxythiophene)- poly(styrenesulfonate) (PEDOT-PSS) plastic electrodes
- 2006
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In: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 18:18, s. 4354-4360
-
Journal article (peer-reviewed)abstract
- The development of printed and flexible (opto)electronics requires specific materials for the device's electrodes. Those materials must satisfy a combination of properties. They must be electrically conducting, transparent, printable, and flexible. The conducting polymer poly(3,4-ethylenedioxythiophene) - poly-(styrenesulfonate) (PEDOT-PSS) is known as a promising candidate. Its conductivity can be increased by 3 orders of magnitude by the secondary dopant diethylene glycol (DEG). This "secondary doping" phenomenon is clarified in a combined photoelectron spectroscopy and scanning probe microscopy investigation. PEDOT-PSS appears to form a three-dimensional conducting network explaining the improvement of its electrical property upon addition of DEG. Polymer light emitting diodes are successfully fabricated using the transparent plastic PEDOT-PSS electrodes instead of the traditionally used indium tin oxide. © 2006 American Chemical Society.
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| 15. |
- Ding, Zhiyi, et al.
(author)
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Targeting s100a9 reduces neutrophil recruitment, inflammation and lung damage in abdominal sepsis
- 2021
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In: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 22:23
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Journal article (peer-reviewed)abstract
- S100A9, a pro-inflammatory alarmin, is up-regulated in inflamed tissues. However, the role of S100A9 in regulating neutrophil activation, inflammation and lung damage in sepsis is not known. Herein, we hypothesized that blocking S100A9 function may attenuate neutrophil recruitment in septic lung injury. Male C57BL/6 mice were pretreated with the S100A9 inhibitor ABR-238901 (10 mg/kg), prior to cercal ligation and puncture (CLP). Bronchoalveolar lavage fluid (BALF) and lung tissue were harvested for analysis of neutrophil infiltration as well as edema and CXC chemokine production. Blood was collected for analysis of membrane-activated complex-1 (Mac-1) expression on neutrophils as well as CXC chemokines and IL-6 in plasma. Induction of CLP mark-edly increased plasma levels of S100A9. ABR-238901 decreased CLP-induced neutrophil infiltration and edema formation in the lung. In addition, inhibition of S100A9 decreased the CLP-induced up-regulation of Mac-1 on neutrophils. Administration of ABR-238901 also inhibited the CLP-induced increase of CXCL-1, CXCL-2 and IL-6 in plasma and lungs. Our results suggest that S100A9 promotes neutrophil activation and pulmonary accumulation in sepsis. Targeting S100A9 function decreased formation of CXC chemokines in circulation and lungs and attenuated sepsis-induced lung damage. These novel findings suggest that S1000A9 plays an important pro-inflammatory role in sepsis and could be a useful target to protect against the excessive inflammation and lung damage associated with the disease.
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| 16. |
- Drouin-Ouellet, Janelle, et al.
(author)
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Age-related pathological impairments in directly reprogrammed dopaminergic neurons derived from patients with idiopathic Parkinson's disease
- 2022
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In: Stem Cell Reports. - : Elsevier BV. - 2213-6711. ; 17:10, s. 2203-2219
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Journal article (peer-reviewed)abstract
- We have developed an efficient approach to generate functional induced dopaminergic (DA) neurons from adult human dermal fibroblasts. When performing DA neuronal conversion of patient fibroblasts with idiopathic Parkinson's disease (PD), we could specifically detect disease-relevant pathology in these cells. We show that the patient-derived neurons maintain age-related properties of the donor and exhibit lower basal chaperone-mediated autophagy compared with healthy donors. Furthermore, stress-induced autophagy resulted in an age-dependent accumulation of macroautophagic structures. Finally, we show that these impairments in patient-derived DA neurons leads to an accumulation of phosphorylated alpha-synuclein, the classical hallmark of PD pathology. This pathological phenotype is absent in neurons generated from induced pluripotent stem cells from the same patients. Taken together, our results show that direct neural reprogramming can be used for obtaining patient-derived DA neurons, which uniquely function as a cellular model to study age-related pathology relevant to idiopathic PD.
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| 17. |
- Edelvik, Fredrik, 1972, et al.
(author)
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An improved method for dipole modeling in EEG-based source localization
- 2009
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In: International Federation for Medical and Biological Engineering Proceedings. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1680-0737. - 9783642038884 ; 25:9, s. 146-149
-
Conference paper (peer-reviewed)abstract
- The inverse problem in EEG-based source localizationis to determine the location of the brain sources that areresponsible for the measured potentials at the scalp electrodes.The brain sources are usually modeled as current dipoles whichlead to a singularity in the right-hand side of the governing Poisson’sequation. Subtraction methods have been proposed as aremedy and in this paper an improved subtraction method formodeling the dipoles is presented. The accuracy is demonstratedfor radial and tangential sources in layered sphere models and isto the best of the authors’ knowledge superior to previous methodsfor superficial sources. An additional advantage is that itproduces a right hand side with few non-zeros which is beneficialfor efficient solution of the inverse problem.
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| 18. |
-
Fritt från fältet : Om medier, generationer och värden. Festskrift till Göran Bolin
- 2019. - 1
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Editorial collection (other academic/artistic)abstract
- Den tionde april 2019 fyllde professor Göran Bolin 60 år. Vänner och kollegor inom medie- och kommunikationsvetenskapen i Sverige och utomlands tog tillfället i akt och förärade honom denna bok.Bidragen i boken tar upp en rad olika teman och ämnen som på olika sätt anknyter till Görans gärning: Här återfinns texter om mediegenerationer, medialisering, fält och kulturell produktion och vår förhoppning är att den återger något av den spännvidd som finns i dagens medievetenskapliga forskning. Vi hoppas också att bokens kapitel i någon mening fångar den slags medievetenskap som vi uppfattar att Göran står för: En medievetenskap som kombinerar samhällsvetenskapliga och humanistiska traditioner, en empirisk, kritisk forskning som närmar sig tidens stora frågor med ett historiskt grundat och teoretiskt välinformerat perspektiv.
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| 19. |
- Gamalielsson, Jonas, et al.
(author)
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On the availability and effectiveness of open source software for digital signing of PDF documents
- 2015
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In: Open Source Systems: Adoption and Impact. - Cham : Springer. - 9783319178363 - 9783319178370 ; , s. 71-80
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Conference paper (peer-reviewed)abstract
- Digital signatures are important in order to ensure the integrity and authenticity of information communicated over the Internet involving different stakeholders within and beyond the borders of different nations. The topic has gained increased interest in the European context and there is legislation and project initiatives aiming to facilitate use and standardisation of digital signatures. Open standards and open source implementations of open standards are important means for the interoperability and long-term maintenance of software systems implementing digital signatures. In this paper we report from a study aiming to establish the availability and effectiveness of software provided under an open source license for digital signing and validation of PDF documents. Specifically, we characterise the use of digital signatures in Swedish Governmental agencies, report on the interoperability of open source and proprietary licensed software for digital signatures in PDF documents, and establish the effectiveness of software provided under an open source license for validation of digital signatures in PDF documents.
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| 20. |
- Gleeson, Daniel, 1988, et al.
(author)
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Generating Optimized Trajectories for Robotic Spray Painting
- 2022
-
In: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; 19:3, s. 1380-1391
-
Journal article (peer-reviewed)abstract
- In the manufacturing industry, spray painting is often an important part of the manufacturing process. Especially in the automotive industry, the perceived quality of the final product is closely linked to the exactness and smoothness of the painting process. For complex products or low batch size production, manual spray painting is often used. But in large scale production with a high degree of automation, the painting is usually performed by industrial robots. There is a need to improve and simplify the generation of robot trajectories used in industrial paint booths. A novel method for spray paint optimization is presented, which can be used to smooth out a generated initial trajectory and minimize paint thickness deviations from a target thickness. The smoothed out trajectory is found by solving, using an interior point solver, a continuous non-linear optimization problem. A two-dimensional reference function of the applied paint thickness is selected by fitting a spline function to experimental data. This applicator footprint profile is then projected to the geometry and used as a paint deposition model. After generating an initial trajectory, the position and duration of each trajectory segment are used as optimization variables. The primary goal of the optimization is to obtain a paint applicator trajectory, which would closely match a target paint thickness when executed. The algorithm has been shown to produce satisfactory results on both a simple 2-dimensional test example, and a non-trivial industrial case of painting a tractor fender. The resulting trajectory is also proven feasible to be executed by an industrial robot.
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| 21. |
- Gleeson, Daniel, 1988, et al.
(author)
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Robot spray painting trajectory optimization
- 2020
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In: IEEE International Conference on Automation Science and Engineering. - 2161-8070 .- 2161-8089. ; 2020-August, s. 1135-1140
-
Conference paper (peer-reviewed)abstract
- In the manufacturing industry, spray painting is often an important part of the process. Especially in the automotive industry, the perceived quality of the final product is closely linked to the exactness and smoothness of the painting process. For complex products or low batch size production, manual spray painting is often used. But in large scale production with a high degree of automation, the painting is normally performed by industrial robots. There is a need to improve and simplify the generation of robot trajectories used in industrial paint booths. A method for spray paint optimization is presented, which can be used to smooth out an initial trajectory and minimize paint thickness deviations from a target thickness. By fitting a spline function to experimental data, an applicator footprint profile is determined, which is a two-dimensional reference function of the applied paint thickness. This footprint profile is then projected to the geometry and used as a deposition model at each point along the trajectory. The positions and durations of all trajectory segments are used as optimization variables. They are modified with the primary goal to obtain a paint applicator trajectory, which will closely match a target paint thickness when executed. The algorithm is shown to produce satisfactory results on both a simple 2-dimensional test example, and a nontrivial industrial case of painting a tractor render. The final trajectory shows an overall thickness close to the target thickness, and the resulting trajectory is feasible to execute directly on an industrial robot.
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| 22. |
- Gonzales-Siles, Lucia, et al.
(author)
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Mass Spectrometry Proteotyping of Streptococcus pneumoniae and commensal Streptococcus: identification of biomarkers for infectious strain characterization
- 2016
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In: 26th ECCMID 2016 Amsterdam, The Netherlands. 9 - 12 April 2016.
-
Conference paper (other academic/artistic)abstract
- Background: Streptococcus pneumoniae (pneumococcus) is the leading cause of community-acquired pneumonia, with morbidity and mortality worldwide. S. pneumoniae belongs to the S. mitis-Group (viridans streptococci), phenotypically and genotypically similar to commensal species of the upper respiratory tract, S. mitis, S. oralis, and S. pseudopneumoniae, causing problems for identifications in clinical laboratories. In this project, we apply state-of-the-art proteomics for Streptococcus spp. 'proteotyping'; identifying and characterizing protein biomarkers for species-level identification, antibiotic resistance, virulence and strain typing for epidemiological analyses (1). Material/methods: Bacterial proteins, from intact bacteria or cell fractions, are bound to a membrane surface, using patented (WO2006068619) FlowCell (LPITM) technology. Peptides are generated from the bound proteins, by enzymatic digestion, separated and analyzed, using LC-MS/MS. The mass spectra profiles are compared to reference peptide sequences and whole genome sequence (wgs) data of the NCBI RefSeq Database. The S. mitis-Group specie, S. pneumoniae, S. mitis, S. oralis, S. psedopneumoniae, as well as the more distantly-related, Group A Streptococcus (GAS) species, S. pyogenes , were analyzed individually and in mixtures, to demonstrate the resolution of proteotyping for differentiating bacteria. Results: Using proteotyping protocols, S. pneumoniae were detected and differentiated from other streptococci, S. mitis, S. oralis, S. psedopneumoniae and the more distant relative, S. pyogenes, by identification of unique discriminatory peptides. Metabolic protein biomarkers were identified, including for antibiotic resistance and virulence. It was possible to find discriminatory biomarkers for a target species when analyzing 1:1 mixes of S. pneumoniae and other species from the S. mitis-Group. The different strains of S. pneumoniae, analyzed in different ratio combinations, were successfully differentiated and identified. For successful proteotyping, a comprehensive and accurate genomic database was observed to be key for obtaining reliable peptide matching and proteotyping data. Importantly, because of observed high rates of misclassified wgs data in the public databases, the taxonomic classifications of genomes in GenBank were analyzed against reference type strain genomes of target species by calculating wgs similarities, using Average Nucleotide Identity with BLAST (ANIb). While wgs data for S. pneumoniae were confirmed to be classified correctly, approximately one-third of wgs data for other species of the S. mitis-Group were determined to be misclassified. Streptococci strains that could not be identified, using standard genotypic and phenotypic approaches, were characterized by proteotyping and genome sequencing to establish their taxonomy and biomarker features to enhance species database matching. Conclusions: Proteotyping enables differentiation, identification and characterization of pneumococcus from the most closely related species attaining, as well, strain-level discrimination from single LC-MS/MS analyses. The protocol enhances identification and characterization of pathogenic bacterial isolates through identifications of expressed biomarkers, ultimately for cultivation-independent analyses of clinical samples. 1) Karlsson et al., 2015. Syst Appl Microbiol. 38:246-257.
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| 23. |
- Gran, Fredrik, et al.
(author)
-
Adaptive spectral Doppler estimation
- 2009
-
In: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. - 0885-3010. ; 56:4, s. 700-714
-
Journal article (peer-reviewed)abstract
- In this paper, 2 adaptive spectral estimation techniques are analyzed for spectral Doppler ultrasound. The purpose is to minimize the observation window needed to estimate the spectrogram to provide a better temporal resolution and gain more flexibility when designing the data acquisition sequence. The methods can also provide better quality of the estimated power spectral density (PSD) of the blood signal. Adaptive spectral estimation techniques are known to provide good spectral resolution and contrast even when the observation window is very short. The 2 adaptive techniques are tested and compared with the averaged periodogram (Welch's method). The blood power spectral capon (BPC) method is based on a standard minimum variance technique adapted to account for both averaging over slow-time and depth. The blood amplitude and phase estimation technique (BAPES) is based on finding a set of matched filters (one for each velocity component of interest) and filtering the blood process over slow-time and averaging over depth to find the PSD. The methods are tested using various experiments and simulations. First, controlled flow-rig experiments with steady laminar flow are carried out. Simulations in Field II for pulsating flow resembling the femoral artery are also analyzed. The simulations are followed by in vivo measurement on the common carotid artery. In all simulations and experiments it was concluded that the adaptive methods display superior performance for short observation windows compared with the averaged periodogram. Computational costs and implementation details are also discussed.
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| 24. |
- Gudmundson, Erik, et al.
(author)
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Overcoming the Nyquist Limit in Blood Flow Velocity Estimation
- 2012
-
In: 2012 IEEE International Ultrasonics Symposium (IUS'12), Proceedings of. - 1948-5719. ; , s. 1615-1618
-
Conference paper (peer-reviewed)abstract
- Spectral Doppler ultrasound imaging typically consists of a spectrogram, showing the velocity distribution of the blood, and a brightness (B-) mode image allowing the operator to navigate. It is desirable to have both high spectral and velocity resolution, so that details in the blood flow can be traced, as well as a high B-mode frame rate to allow for tracking of movements and to adjust the position of the transducer. The blood flow signal is often sampled 1) using alternating transmissions for blood flow estimation and for B-mode imaging, or, 2) by acquiring a full Doppler spectrum and then parts of the B-mode image. The former has the disadvantage that it halves the sampling rate, making it likely that aliasing will occur when imaging fast moving blood or deeply positioned vessels; the latter that gaps appears in the spectrogram, and that if the frame rate of the B-mode images is slow, it will be difficult to track movements. Adaptive methods have been implemented to circumvent such problems, but even so, to get an acceptable frame rate of the B- mode images, the number of transmissions for Doppler estimation will be limited, restricting the spectral resolution. Alternatively, one may use an irregularly spaced emission pattern, but existing work on the topic is limited and generally suffers from poor resolution and spurious velocity components resulting from the irregular sampling pattern. In this paper, we examine the BIAA algorithm, showing that this approach allows for an accurate velocity estimate even from irregularly sampled measurements. Using an irregular emission pattern, with half the emissions used to form the B-mode image, the remaining emissions are found to yield accurate velocity estimates without reducing the maximally measurable velocity and without the spurious velocity components. Moreover, we show that the approach will allow for the same maximal velocity without aliasing as if all emissions would have been used for the velocity estimation.
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| 25. |
- Gutte, Henrik, et al.
(author)
-
Automated interpretation of PET/CT images in patients with lung cancer.
- 2007
-
In: Nuclear Medicine Communications. - 1473-5628. ; 28:2, s. 79-84
-
Journal article (peer-reviewed)abstract
- Purpose: To develop a completely automated method based on image processing techniques and artificial neural networks for the interpretation of combined [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) and computed tomography (CT) images for the diagnosis and staging of lung cancer. Methods: A total of 87 patients who underwent PET/CT examinations due to suspected lung cancer comprised the training group. The test group consisted of PET/CT images from 49 patients suspected with lung cancer. The consensus interpretations by two experienced physicians were used as the 'gold standard' image interpretation. The training group was used in the development of the automated method. The image processing techniques included algorithms for segmentation of the lungs based on the CT images and detection of lesions in the PET images. Lung boundaries from the CT images were used for localization of lesions in the PET images in the feature extraction process. Eight features from each examination were used as inputs to artificial neural networks trained to classify the images. Thereafter, the performance of the network was evaluated in the test set. Results: The performance of the automated method measured as the area under the receiver operating characteristic curve, was 0.97 in the test group, with an accuracy of 92%. The sensitivity was 86% at a specificity of 100%. Conclusions: A completely automated method using artificial neural networks can be used to detect lung cancer with such a high accuracy that the application as a clinical decision support tool appears to have significant potential.
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| 26. |
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| 27. |
- Hedenus, Fredrik, 1976, et al.
(author)
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Historical wind deployment and implications for energy system models
- 2022
-
In: Renewable and Sustainable Energy Reviews. - : Elsevier BV. - 1879-0690 .- 1364-0321. ; 168
-
Journal article (peer-reviewed)abstract
- A critical parameter in modeling studies of future decarbonized energy systems is the potential future capacity for onshore wind power. Wind power potential in energy system models is subject to assumptions regarding: (i) constraints on land availability for wind deployment; (ii) how densely wind turbines may be placed over larger areas, and (iii) allocation of capacity with respect to wind speed. By analyzing comprehensive databases of wind turbine locations and other GIS data in eleven countries and seventeen states in Australia, Canada, and the US; all with high penetration levels of wind power, we find that: i) large wind turbines are installed on most land types, even protected areas and land areas with high population density; ii) it is not uncommon with a deployment density up to 0.5 MW/km2 on municipality or county level, with rare outlier municipalities reaching up to 1.5 MW/km2 installed capacity; and iii) wind power has historically been allocated to relatively windy sites with average wind speed above 6 m/s. In many cases, allocation methods used in energy system models do not consistently reflect actual installations. For instance, we find no evidence of concentration of installations at the windiest sites, as is frequently assumed in energy system models. We conclude that assumptions made in models regarding wind power potentials are poorly reflective of historical installation patterns, and we provide new data to enable assumptions that have a more robust empirical foundation.
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| 28. |
- Hellström, Ann, 1959, et al.
(author)
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Extreme prematurity, treated retinopathy, bronchopulmonary dysplasia and cerebral palsy are significant risk factors for ophthalmological abnormalities at 6.5years of age
- 2018
-
In: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 107:5, s. 811-821
-
Journal article (peer-reviewed)abstract
- Aim: This study evaluated the contributions of various prenatal and postnatal predictive factors to a documented high prevalence of ophthalmological abnormalities in children aged 6.5 years who were born extremely preterm. Methods: We carried out a prospective population-based study of all children born in Sweden at a gestational age of 22+0 to 26+6weeks based on the Extremely Preterm Infants in Sweden Study. The main outcome measures were a combined score of visual impairment, refractive errors and strabismus at 6.5years of age. Models of univariate and multivariable regression were used to analyse potential prenatal and postnatal predictive factors at different clinically relevant time-points from one minute after birth to 30months. Results: We focused on 399 known extremely preterm survivors and compared them to 300 full-term controls. Significant antecedents for ophthalmological abnormalities included prematurity per se, retinopathy of prematurity that required treatment, severe bronchopulmonary dysplasia and cerebral palsy. Severe intraventricular haemorrhage was no longer a significant risk factor when we adjusted it for the 30-month cognitive and neuromotor development outcomes. Conclusion: This time-course risk analysis model showed a changing panorama of significant risk factors for ophthalmological abnormalities in children aged 6.5years who were born extremely preterm.
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| 29. |
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| 30. |
- Heurlin, Fredrik, et al.
(author)
-
Front passenger airbag benefits for restrained forward‐facing children
- 2016
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In: IRCOBI Conf Proc - International Research Council on the Biomechanics of Injury, Sept, Malaga, Spain (IRC-16-43). - 2235-3151.
-
Journal article (peer-reviewed)abstract
- This study investigates whether the front passenger airbag disabling strategy, developed based onfirst‐generation airbags, is valid for modern airbag designs and restrained forward‐facing children fromthree‐year‐old (3YO) size. In total, 19 different frontal impact situations were evaluated, comparing with andwithout airbag activation, using one vehicle model. Restrained child crash test dummies (3YO, 6YO, 10YO), ofvaried seat positions, booster types, crash pulses and sitting postures (up‐right and forward leaning), weretested in sled tests representative of a modern airbag and seatbelt technology. In addition, some typical misusecases were evaluated.To different extents, all 19 situations tested demonstrated relative positive, or comparable, effect foractivated airbag compared to no airbag. The influence of the airbag was relatively more pronounced in themore forward seat adjustment positions. In the misuse situations, it was clearly more robust using the airbag tohelp protect the child. Based on the results, Volvo Cars is revising its recommendations for restrained forwardfacing children travelling in car models with front passenger airbag designs as tested in this study. For thesespecific car models it is revised to recommend that the airbag should be Enabled for all forward‐facingrestrained child occupants (as for adults), while kept Disabled for all rearward‐facing children.
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| 31. |
- Holmström, Gerd E, et al.
(author)
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Ophthalmologic Outcome at 30 Months Corrected Age of a Prospective Swedish Cohort of Children Born Before 27 Weeks of Gestation The Extremely Preterm Infants in Sweden Study
- 2014
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In: JAMA OPHTHALMOLOGY. - : American Medical Association (AMA). - 2168-6165 .- 2168-6173. ; 132:2, s. 182-189
-
Journal article (peer-reviewed)abstract
- IMPORTANCE Follow-up at 30 months corrected age reveals eye and visual problems in one-third of children born extremely prematurely (less than27 weeks gestation). OBJECTIVE To investigate the ophthalmologic outcome of extremely preterm children at 30 months corrected age. DESIGN, SETTING, AND PARTICIPANTS A prospective, population-based follow-up study (Extremely Preterm Infants in Sweden Study [EXPRESS]) was conducted in Sweden. The population included extremely preterm infants (less than27 weeks gestation) born in Sweden between 2004 and 2007, of whom 491 survived until age 2.5 years. Screening for retinopathy of prematurity (ROP) was performed in the neonatal period. At 30 months corrected age, an ophthalmologic assessment was performed in 411 of 491 children (83.7%). MAIN OUTCOMES AND MEASURES Visual acuity, manifest strabismus, and refractive errors were evaluated. RESULTS Visual impairment was identified in 3.1% of the children, and 1.0% were blind. Refractive errors, defined as myopia less than -3 diopters (D), hypermetropia greater than +3 D, astigmatism 2 D or more, and/or anisometropia 2 D or more, were found in 25.6% of the children, and 14.1% had manifest strabismus. There were significant associations between visual impairment and treated ROP (P = .02), cognitive disability (P less than .001), and birth weight (P = .02). Multiple regression analyses revealed significant associations between strabismus and treated ROP (P less than .001), cognitive disability (P less than .01), and cerebral palsy (P = .02). Refractive errors were significantly correlated with severity of ROP (right eye, P less than .001; left eye, P less than .01). Children who had been treated for ROP had the highest frequency (69.0%) of eye and visual abnormalities. CONCLUSIONS AND RELEVANCE One-third of the extremely prematurely born children in this study had some kind of eye or visual problems, such as visual impairment, strabismus, or major refractive error. Despite being born extremely preterm, the present cohort has a similar prevalence of blindness and visual impairment as in previous Swedish cohorts of children born less prematurely.
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| 32. |
- Jakobsson, Annika, 1949, et al.
(author)
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Developing a willingness to change: treatment-seeking processes for people with alcohol problems.
- 2005
-
In: Alcohol Alcohol. ; Mar-Apr;40:2, s. 118-23
-
Journal article (peer-reviewed)abstract
- AIMS: The study explores treatment-seeking processes in men and women with alcohol problems, focusing on promoting and hindering factors. METHODS: Open interviews were held with five women and seven men within a month of their first voluntary treatment for alcohol problems. The interview protocols were analysed consecutively in accordance with grounded theory methodology. RESULTS: Developing a willingness to change was found to be the basic psychosocial process that lead to treatment-seeking. Categories that constituted sub-processes and supported willingness to change were: (i) actuating inner forces; (ii) dealing with conflicting feelings and thoughts; and (iii) hoping to turn the situation around. These processes were continuously assisted by demanding and caring support from partners, friends or professionals. CONCLUSIONS: The processes that precede treatment-seeking were highly complex, and both internal and external factors promoted and hindered treatment entry. The social significance of alcohol and the grief related to thoughts of abstaining were the most striking hindering factors. Such feelings need to be considered when motivating people to seek treatment for alcohol problems.
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| 33. |
- Jakobsson, Annika, 1949, et al.
(author)
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Possibilities and Hindrances for Prevention of Intimate Partner Violence: Perceptions Among Professionals and Decision Makers in a Swedish Medium-Sized Town.
- 2013
-
In: International journal of behavioral medicine. - : Springer Science and Business Media LLC. - 1532-7558 .- 1070-5503. ; 20:3, s. 337-343
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Intimate partner violence (IPV) is a major public health problem, but few evidence-based prevention programs have yet been implemented. PURPOSE: This study explored the perceptions and beliefs of local-level decision makers, social and health-care professionals, and representatives from the police force regarding the possibilities and hindrances for prevention of IPV. METHOD: An explorative qualitative approach was used, and participants were strategically selected for focus group discussions. The participants, 19 men and 23 women, were professionals or decision makers within health-care services, social welfare, municipal administration, the police force, local industry, and local politicians in a Swedish town of 54,000 inhabitants. The focus group discussions were audio recorded, transcribed verbatim, and thematically analyzed. A manifest content analysis was performed on the text. RESULTS: Preschools, schools, sports associations, workplaces, and the mass media were suggested as possible arenas for prevention measures. The proposed activities included norm building and improved social support structures. Hindrances were conceptualized as societal beliefs and attitudes, shame, silence, gender inequality, the counteracting influence of the media, and lack of resources. The participants demonstrated closeness and distance to IPV, expressed as acceptance or referral of responsibility to others regarding where and by whom prevention measures should be executed. CONCLUSION: This study gave new insights in the prevailing perceptions of professionals and decision makers of a medium-sized Swedish town, which can be a useful knowledge in future preventive work and contribute to bridge the gap between research and practice.
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| 34. |
- Jakobsson, Annika, 1949, et al.
(author)
-
The role of gendered conceptions in treatment seeking for alcohol problems
- 2008
-
In: Scandinavian Journal of Caring Sciences. - : Wiley. - 0283-9318 .- 1471-6712. ; 22:2, s. 196-202
-
Journal article (peer-reviewed)abstract
- The aim of this study was to explore the inducements for treatment-seeking for alcohol problems in women and men. Specifically we wanted to identify what promoted or hindered treatment-seeking in women and men, respectively, and to what extent femininity and masculinity was reflected in the context of treatment seeking. Data was obtained from open interviews with five women and seven men within a month after their first entry into alcohol treatment. A content analysis was performed using gender as the sorting factor. Promoting factors for treatment seeking in men were characterized by belief in their own capability, and looking to the future; whereas the women placed importance on pressure from someone significant, and sharing the problem with others. Hindrances for both women and men were feelings of shame and the significant role alcohol had in their lives. The women perceived alcohol problems as incompatible with femininity, and this made them avoid talking openly about their problems, which hence hindered treatment seeking. These findings showed that the value of alcohol as a gendered symbol still exists, which could be perceptible in promoting and hindering factors for treatment seeking in women and men. These factors could be useful to consider by professionals both in the primary healthcare system and in the social services. Future research should address treatment seeking in relation to both cultural and gendered constructions and their influence on the perceptions and behaviour of women and men with alcohol problems.
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| 35. |
- Jakobsson, Albin, et al.
(author)
-
Three-dimensional functional human neuronal networks in uncompressed low-density electrospun fiber scaffolds
- 2017
-
In: Nanomedicine. - : Elsevier. - 1549-9634 .- 1549-9642. ; 13:4, s. 1563-1573
-
Journal article (peer-reviewed)abstract
- We demonstrate an artificial three-dimensional (3D) electrical active human neuronal network system, by the growth of brain neural progenitors in highly porous low density electrospun poly-ε-caprolactone (PCL) fiber scaffolds. In neuroscience research cell-based assays are important experimental instruments for studying neuronal function in health and disease. Traditional cell culture at 2D-surfaces induces abnormal cell–cell contacts and network formation. Hence, there is a tremendous need to explore in vivo-resembling 3D neural cell culture approaches. We present an improved electrospinning method for fabrication of scaffolds that promote neuronal differentiation into highly 3D integrated networks, formation of inhibitory and excitatory synapses and extensive neurite growth. Notably, in 3D scaffolds in vivo-resembling intermixed neuronal and glial cell network were formed, whereas in parallel 2D cultures a neuronal cell layer grew separated from an underlying glial cell layer. Hence, the use of the 3D cell assay presented will most likely provide more physiological relevant results.
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| 36. |
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| 37. |
- Jakobsson, Fredrik Lars Emil, 1974-
(author)
-
Charge transport modulation in organic electronic diodes
- 2008
-
Doctoral thesis (other academic/artistic)abstract
- Since the discovery of conducting polymers three decades ago the field of organic electronics has evolved rapidly. Organic light emitting diodes have already reached the consumer market, while organic solar cells and transistors are rapidly maturing. One of the great benefits with this class of materials is that they can be processed from solution. This enables several very cheap production methods, such as printing and spin coating, and opens up the possibility to use unconventional substrates, such as flexible plastic foils and paper. Another great benefit is the possibility of tailoring the molecules through carefully controlled synthesis, resulting in a multitude of different functionalities.This thesis reports how charge transport can be altered in solid-state organic electronic devices, with specific focus on memory applications. The first six chapters give a brief review of the field of solid-state organic electronics, with focus on electronic properties, resistance switch mechanisms and systems. Paper 1 and 3 treat Rose Bengal switch devices in detail – how to improve these devices for use in cross-point arrays as well as the origin of the switch effect. Paper 2 investigates how the work function of a conducting polymer can be modified to allow for better electron injection into an organic light emitting diode. The aim of the work in papers 4 and 5 is to understand the behavior of switchable charge trap devices based on blends of photochromic molecules and organic semiconductors. With this in mind, charge transport in the presence of traps is investigated in paper 4 and photochromic molecules is investigated using quantum chemical methods in paper 5.
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| 38. |
- Jakobsson, Fredrik L. E., et al.
(author)
-
Filamentary switching of Rose Bengal devices
-
Other publication (other academic/artistic)abstract
- Switch devices with a structure of metal / orgamc layer / metal were fabricated, with the organic layer being Rose Bengal sodium salt, Rose Bengal bis(tricthylammonium) salt, Rose Bengal lactone and Fluorescein. All devices showed reversible switch behavior, ruling out electro reduction or conformational switching. Furthermore, only devices with ITO as substrate and Al or Ag as top electrode showed reversible switch behavior. Electrical characterization of the ITO substrate indicated that the switching is due to the reversible formation of conducting filaments, initiated from the ITO.
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| 39. |
- Jakobsson, Fredrik L.E. 1974-, et al.
(author)
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On the switching mechanism in Rose Bengal-based memory devices
- 2007
-
In: Organic electronics. - : Elsevier BV. - 1566-1199. ; 8:5, s. 559 -565
-
Journal article (peer-reviewed)abstract
- Impedance switching has been observed in many organic devices, but the mechanism is still a matter of debate. Reliable switch devices consisting of an organic layer of Rose Bengal derivatives sandwiched in between indium tin oxide and aluminum electrodes were fabricated. Modifying the chemical nature of the organic layers and visualizing the temperature distribution in the organic memory rule out several mechanisms. It is shown that the memory effect originates from filamentary switching.
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| 40. |
- Jakobsson, Fredrik L. E., 1974-, et al.
(author)
-
Prediction of the current versus voltage behavior of devices based on organic semiconductor host-guest systems
- 2009
-
In: Organic electronics. - : Elsevier BV. - 1566-1199 .- 1878-5530. ; 10:1, s. 95-106
-
Journal article (peer-reviewed)abstract
- Organic semiconductor blends are commonly used in organic based (opto-)electronic devices. They are composed of two types of (macro-) molecules, referredto as the guest and host. To achieve optimum device operation, the chemicalnature, electronic structure, molecular order and the relative concentration of theguests and host are crucial. Here, we present simulation results of the currentdensity versus the voltage (J-V) behavior of a two-terminal device based on avariable-range hopping model in which the electronic states of the guest and hostare represented by two Gaussian distributions. The J-V behavior is investigatedfor various energetic mismatches between guest and host states, widths of thedistribution as well as the guest concentration. Finally, a simple tool enablingeasy prediction of the J-V behavior of organic host-guest diodes is derived.
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| 41. |
- Jakobsson, Fredrik L. E., 1974-, et al.
(author)
-
Towards addressable organic impedance switch devices
- 2005
-
In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 87:6
-
Journal article (peer-reviewed)abstract
- The addressability of organic impedance switch devices as the memory elements of cross-point matrices is improved by introducing nonlinear behavior in their current-voltage characteristics. This is realized by adding a semiconducting layer of copper (II) phthalocyanine (CuPc) on top of the switch layer of Rose Bengal (RB) sodium salt. Leakage currents from unaddressed cells in a matrix are reduced by a factor of 17; thus improving the signal-to-background ratio, reducing driver currents and limiting the potential drop along the addressing lines. The matrix size of RB switch devices, using organic conductors, is predicted to be increased by 32 times when using the additional CuPc layer.
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| 42. |
- Jakobsson, Fredrik L. E., 1974-, et al.
(author)
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Towards all-plastic flexible light emitting diodes
- 2006
-
In: Chemical Physics Letters. - : Elsevier BV. - 0009-2614 .- 1873-4448. ; 433:1-3, s. 110-114
-
Journal article (peer-reviewed)abstract
- All-plastic light emitting diodes require the design and fabrication of low work function plastic electrodes. Here, we show that the work function of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT-PSS) can be decreased from 4.8 eV to 3.9 eV by surface reaction with the strong electron-donor tetrakis(dimethylamino)ethylene (TDAE). The surface modification was characterized by photoelectron spectroscopy and optical spectroscopy. The low work function plastic electrode was used in a first prototype for all-plastic light emitting diodes.
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| 43. |
- Jakobsson, Fredrik L. E., 1974-, et al.
(author)
-
Tuning the energy levels of photochromic diarylethene compounds for optoelectronic switch devices
-
Other publication (other academic/artistic)abstract
- Photochromic diarylethene molecules (PC) is investigated for use in opticalwrite/electrical read memory applications. The frontier energy levels and dipolemoment is calculated using density functional theory. Good agreement is foundbetween calculated electronic structure and measured ultraviolet photoelectronspectra. The changes in frontier energy levels and dipole moment are scrutinizedupon two different approaches for chemical modification: (i) adding substituentsto the ethylene bridge; or (ii) changing the chemical nature of the aryl rings.Through the chemical modification the frontier energy levels can be tuned bymore than 2 eV. The calculated molecular properties are used in charge transportmodels to predict the behavior of devices based on these molecules. By using thePC in combination with an organic semiconductor (in bilayer or blend) goodswitching behavior can be achieved in a device. The switch effect is predicted tobe mainly due to switch in frontier energy levels rather than switch of dipolemoment. This is concluded since the dipole moment is either too small (< 5 D) orthe switch effect to small (less than a factor of two).
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| 44. |
- Jakobsson, Fredrik, 1974-
(author)
-
Organic electronic switch devices
- 2006
-
Licentiate thesis (other academic/artistic)abstract
- Since the discovery of conducting polymers three decades ago the field of organic electronics has evolved rapidly. Organic light emitting diodes have already reached the consumer market, while organic solar cells and transistors are rapidly maturing. One of the great benefits with this class of materials is that they can be processed from solution. This enables several very cheap production methods, such as printing and spin coating, and opens up the possibility to use unconventional substrates, such as flexible plastic foils and paper. Another great benefit is the possibility of tailoring the molecules through carefully controlled synthesis, resulting in a multitude of different functionalities. This is very interesting for nano applications, where devices are made of a small number of molecules or even a single molecule, and were the molecules can be designed to self-assembly.This thesis reports how charge transport can be altered in solid-state organic electronic devices. This is done from both a dynamic perspective, as in impedance switch devices, and from a static perspective, as in the modification of electrode properties to improve charge injection. The first six chapters give a brief review of the field of solid-state organic electronics, with focus on electronic properties, impedance switch mechanisms and architecture.Paper I and III treat Rose Bengal switch devices in detail- how to improve these devices for use in cross-point arrays (paper I) and the origin of the switch effect (paper III). Paper II investigates how the work function of a conducting polymer can be modified to allow for better electron injection into an organic light emitting diode.
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| 45. |
- Jakobsson, Fredrik, et al.
(author)
-
Tuning the Energy Levels of Photochromic Diarylethene Compounds for Opto-electronic Switch Devices
- 2009
-
In: JOURNAL OF PHYSICAL CHEMISTRY C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 113:42, s. 18396-18405
-
Journal article (peer-reviewed)abstract
- Diarylethene molecules are photochromics (PCs) currently investigated for use in optical write/electrical read memory applications. The impact of the photoisomerization of PCs on the device behavior is analyzed with charge transport models. These results indicate that good electrical current switching can be achieved in a device when the PCs are combined with an organic semiconductor (in multilayered structures or blends). The frontier energy levels and dipole moment of a series of diarylethene compounds have been calculated using density functional theory. A good agreement is found between the calculated electronic structure and the measured ultraviolet photoelectron spectra. Shirts in the frontier energy levels and dipole moment are generated through two different approaches for chemical modification: (i) by changing the chemical nature of the aryl rings or (ii) by adding substituents on the ethylene, bridge. The frontier energy levels can be tuned by more than 2 eV via such chemical modifications. We find that, for this family of photochromic compounds, the photoinduced current switch effect in diodes is mainly due to the modulation in the frontier energy levels rather than the changes in the amplitude of the dipole moment.
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| 46. |
- Jakobsson, Håkan, et al.
(author)
-
Adaptive component mode synthesis in linear elasticity
- 2011
-
In: International Journal for Numerical Methods in Engineering. - : Wiley. - 0029-5981 .- 1097-0207. ; 86:7, s. 801-934
-
Journal article (peer-reviewed)abstract
- Component mode synthesis (CMS) is a classical method for the reduction of large-scale finite element models in linear elasticity. In this paper we develop a methodology for adaptive refinement of CMS models. The methodology is based on a posteriori error estimates that determine to what degree each CMS subspace influence the error in the reduced solution. We consider a static model problem and prove a posteriori error estimates for the error in a linear goal quantity as well as in the energy and L2 norms. Automatic control of the error in the reduced solution is accomplished through an adaptive algorithm that determines suitable dimensions of each CMS subspace. The results are demonstrated in numerical examples.
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| 47. |
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| 48. |
- Jakobsson, Håkan, et al.
(author)
-
Duality-based adaptive model reduction for one-way coupled thermoelastic problems
- 2012
-
In: International Journal for Numerical Methods in Engineering. - : Wiley. - 0029-5981 .- 1097-0207. ; 91:3, s. 306-318
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Journal article (other academic/artistic)abstract
- In this paper, we derive a discrete a posteriori error estimate for a thermoelastic model problem discretized using a reduced finite element method. The problem is one-way coupled in the sense that heat transfer affects elastic deformation but not vice versa. A reduced model is constructed using component mode synthesis in each of the heat transfer and linear elastic finite element solvers. The error estimate bounds the difference between the reduced and the standard finite element solution in terms of discrete residuals and corresponding dual weights. A main feature with the estimate is that it automatically gives a quantitative measure of the propagation of error between the solvers with respect to a certain computational goal. The analytical results are accompanied by a numerical example.
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| 49. |
- Jakobsson, Hedvig E, et al.
(author)
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Draft Genome Sequence of Moraxella catarrhalis Type Strain CCUG 353T.
- 2016
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In: Genome Announcements. - 2169-8287. ; 4:3
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Journal article (peer-reviewed)abstract
- Moraxella catarrhalis is a Gram-negative commensal and pathogenic bacterium found in the human respiratory tract. It is associated with otitis media and respiratory tract infections. Here, we report the draft genome sequence of M. catarrhalis type strain CCUG 353(T), composed of 18 contigs and a total size of 1.89 Mb.
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| 50. |
- Jakobsson, Hedvig E, et al.
(author)
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Draft Genome Sequences of Six Strains of Streptococcus pneumoniae from Serotypes 5, 6A, 6B, 18C, 19A, and 23F
- 2017
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In: Genome Announcements. - 2169-8287. ; 5:14
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Journal article (peer-reviewed)abstract
- Streptococcus pneumoniae is a pathogenic bacterium found most commonly in the respiratory tract of humans and is a common cause of pneumonia and bacterial meningitis. Here, we report the draft genome sequences of six S. pneumoniae strains: CCUG 1350, CCUG 7206, CCUG 11780, CCUG 33774, CCUG 35180, and CCUG 35272.
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