SwePub
Sök i SwePub databas

  Extended search

Träfflista för sökning "WFRF:(Karlsson Jan Erik) "

Search: WFRF:(Karlsson Jan Erik)

  • Result 1-25 of 218
Sort/group result
   
EnumerationReferenceCoverFind
1.
  • Nordanstig, Annika, 1974, et al. (author)
  • EndoVAscular treatment and ThRombolysis for Ischemic Stroke Patients (EVA-TRISP) registry: basis and methodology of a pan-European prospective ischaemic stroke revascularisation treatment registry.
  • 2021
  • In: BMJ open. - : BMJ. - 2044-6055. ; 11:8
  • Journal article (peer-reviewed)abstract
    • The Thrombolysis in Ischemic Stroke Patients (TRISP) collaboration was a concerted effort initiated in 2010 with the purpose to address relevant research questions about the effectiveness and safety of intravenous thrombolysis (IVT). The collaboration also aims to prospectively collect data on patients undergoing endovascular treatment (EVT) and hence the name of the collaboration was changed from TRISP to EVA-TRISP. The methodology of the former TRISP registry for patients treated with IVT has already been published. This paper focuses on describing the EVT part of the registry.All centres committed to collecting predefined variables on consecutive patients prospectively. We aim for accuracy and completeness of the data and to adapt local databases to investigate novel research questions. Herein, we introduce the methodology of a recently constructed academic investigator-initiated open collaboration EVT registry built as an extension of an existing IVT registry in patients with acute ischaemic stroke (AIS).Currently, the EVA-TRISP network includes 20 stroke centres with considerable expertise in EVT and maintenance of high-quality hospital-based registries. Following several successful randomised controlled trials (RCTs), many important clinical questions remain unanswered in the (EVT) field and some of them will unlikely be investigated in future RCTs. Prospective registries with high-quality data on EVT-treated patients may help answering some of these unanswered issues, especially on safety and efficacy of EVT in specific patient subgroups.This collaborative effort aims at addressing clinically important questions on safety and efficacy of EVT in conditions not covered by RCTs. The TRISP registry generated substantial novel data supporting stroke physicians in their daily decision making considering IVT candidate patients. While providing observational data on EVT in daily clinical practice, our future findings may likewise be hypothesis generating for future research as well as for quality improvement (on EVT). The collaboration welcomes participation of further centres willing to fulfill the commitment and the outlined requirements.
  •  
2.
  • Blomstrand, Peter, et al. (author)
  • Pulsed tissue Doppler imaging for the detection of myocardial ischaemia, a comparison with myocardial perfusion SPECT
  • 2004
  • In: Clinical Physiology and Functional Imaging. - : John Wiley & Sons. - 1475-0961 .- 1475-097X. ; 24:5, s. 289-295
  • Journal article (peer-reviewed)abstract
    • In order to compare the diagnostic ability of pulsed tissue Doppler and myocardial perfusion Single Photon Emission Computed Tomography (SPECT) in patients with a history of unstable coronary artery disease, CAD, 26 patients, 22 men and four women, age 47-76 years, were investigated in a prospective study, 5-10 day after an episode of unstable angina. Tissue Doppler and two-dimensional echocardiography were performed during dobutamine stress testing and myocardial scintigraphy after bicycle exercise and at rest. Patients with a normal SPECT had higher peak systolic velocity during dobutamine infusion, 18.9 ± 4.1 cm s-1, than patients with ischaemia, 12.2 ± 3.8 cm s-1 (P<0.001) or scar, 8.8 ± 3.0 cm s-1 (P<0.01). In a territorial analysis the difference in peak systolic velocity between areas with a normal and abnormal SPECT was less apparent. Failure to achieve ≥13 cm s-1 in mean-peak systolic velocity was the most accurate criterion for detection of significant CAD on SPECT. We conclude that pulsed tissue Doppler can be used for objective quantification of left ventricular wall motion during dobutamine stress testing and for identification of patients with CAD on SPECT but not for identification of regional ischaemia.
  •  
3.
  • Andersson, Jan, et al. (author)
  • Fisk- och skaldjursbestånd i hav och sötvatten 2015 : Resursöversikt
  • 2015
  • Reports (other academic/artistic)abstract
    • I rapporten kan du ta del av bedömningen som görs av situationen för bestånd som regleras inom ramen för EU:s gemensamma fiskeripolitik (GFP). Bedömningarna baseras på det forskningssamarbete och den rådgivning som sker inom det Internationella Havsforskningsrådet (ICES).De bestånd som förvaltas nationellt baseras på de biologiska underlagen och rådgivningen i huvudsak på den forskning och övervakning samt analys som bedrivs av Institutionen för akvatiska resurser (SLU Aqua) vid Sveriges lantbruksuniversitet (SLU) samt yrkesfiskets rapportering.Rapporten omfattar 40 fiskarter uppdelade i olika bestånd, samt sex skal-och blötdjursarter.Nytt för årets upplaga är en beskrivning av hur de provfisken som ligger till grund för analys och rådgivning utförs.Översikten är utarbetad av Sveriges lantbruksuniversitet (SLU), Institutionen för akvatiska resurser (SLU Aqua), på uppdrag av Havs- och vattenmyndigheten.
  •  
4.
  • Berglund, Erik, et al. (author)
  • Intracellular concentration of the tyrosine kinase inhibitor imatinib in gastrointestinal stromal tumor cells.
  • 2014
  • In: Anti-Cancer Drugs. - 0959-4973 .- 1473-5741. ; 25:4, s. 415-22
  • Journal article (peer-reviewed)abstract
    • Gastrointestinal stromal tumor (GIST) is the most common mesenchymal neoplasm in the gastrointestinal tract. In most GISTs, the underlying mechanism is a gain-of-function mutation in the KIT or the PDGFRA gene. Imatinib is a tyrosine kinase inhibitor that specifically blocks the intracellular ATP-binding sites of these receptors. A correlation exists between plasma levels of imatinib and progression-free survival, but it is not known whether the plasma concentration correlates with the intracellular drug concentration. We determined intracellular imatinib levels in two GIST cell lines: the imatinib-sensitive GIST882 and the imatinib-resistant GIST48. After exposing the GIST cells to imatinib, the intracellular concentrations were evaluated using LC-MS (TOF). The concentration of imatinib in clinical samples from three patients was also determined to assess the validity and reliability of the method in the clinical setting. Determination of imatinib uptake fits within detection levels and values are highly reproducible. The GIST48 cells showed significantly lower imatinib uptake compared with GIST882 in therapeutic doses, indicating a possible difference in uptake mechanisms. Furthermore, imatinib accumulated in the tumor tissues and showed intratumoral regional differences. These data show, for the first time, a feasible and reproducible technique to measure intracellular imatinib levels in experimental and clinical settings. The difference in the intracellular imatinib concentration between the cell lines and clinical samples indicates that drug transporters may contribute toward resistance mechanisms in GIST cells. This highlights the importance of further clinical studies to quantify drug transporter expression and measure intracellular imatinib levels in GIST patients.
  •  
5.
  •  
6.
  • El-Saadi, Walid, 1984-, et al. (author)
  • A head-to-head comparison of myocardial strain by fast-strain encoding and feature tracking imaging in acute myocardial infarction
  • 2022
  • In: Frontiers in Cardiovascular Medicine. - : Frontiers Media SA. - 2297-055X. ; 9
  • Journal article (peer-reviewed)abstract
    • BackgroundMyocardial infarction (MI) is a major cause of heart failure. Left ventricular adverse remodeling is common post-MI. Several studies have demonstrated a correlation between reduced myocardial strain and the development of adverse remodeling. Cardiac magnetic resonance (CMR) with fast-strain encoding (fast-SENC) or feature tracking (FT) enables rapid assessment of myocardial deformation. The aim of this study was to establish a head-to-head comparison of fast-SENC and FT in post-ST-elevated myocardial infarction (STEMI) patients, with clinical 2D speckle tracking echocardiography (2DEcho) as a reference. MethodsThirty patients treated with primary percutaneous coronary intervention for STEMI were investigated. All participants underwent CMR examination with late gadolinium enhancement, cine-loop steady-state free precession, and fast-SENC imaging using a 1.5T scanner as well as a 2DEcho. Global longitudinal strain (GLS), segmental longitudinal strain (SLS), global circumferential strain (GCS), and segmental circumferential strain (SCS) were assessed along with the MI scar extent. ResultsThe GCS measurements from fast-SENC and FT were nearly identical: the mean difference was 0.01 (2.5)% (95% CI - 0.92 to 0.95). For GLS, fast-SENC values were higher than FT, with a mean difference of 1.8 (1.4)% (95% CI 1.31-2.35). Tests of significance for GLS did not show any differences between the MR methods and 2DEcho. Average strain in the infarct-related artery (IRA) segments compared to the remote myocardium was significantly lower for the left anterior descending artery and right coronary artery culprits but not for the left circumflex artery culprits. Fast-SENC displayed a higher area under the curve for detecting infarcted segments than FT for both SCS and SLS. ConclusionGLS and GCS did not significantly differ between fast-SENC and FT. Both showed acceptable agreement with 2DEcho for longitudinal strain. Segments perfused by the IRA showed significantly reduced strain values compared to the remote myocardium. Fast-SENC presented a higher sensitivity and specificity for detecting infarcted segments than FT.
  •  
7.
  •  
8.
  • El-Saadi, Walid, et al. (author)
  • Four- to seven-year follow-up of pharmacological postconditioning with mangafodipir as an adjunct to primary PCI in ST-segment elevation myocardial infarction
  • 2023
  • In: Clinical Physiology and Functional Imaging. - : WILEY. - 1475-0961 .- 1475-097X. ; 43:6, s. 413-420
  • Journal article (peer-reviewed)abstract
    • IntroductionAdverse left ventricular remodelling (AR) develops over time in approximately 30% of patients with a history of coronary artery disease. AR manifests as a structural change in the left ventricle (LV) in terms of increased volumes and reduced left ventricular ejection fraction (LVEF). Manganese dipyridoxyl diphosphate (mangafodipir) has demonstrated interesting cardioprotective features in acute myocardial ischaemia. Pharmacological postconditioning (PP) with mangafodipir as an adjunct to primary percutaneous coronary intervention may possibly reduce the development of AR over time in ST-elevation myocardial infarction (STEMI). The aim of this 4-7-year follow-up study is to investigate the potential benefits of PP with mangafodipir in STEMI patients. MethodThirteen out of the initial 20 patients that were included in the primary study of Karlsson et al. were followed up between April and June 2017. The study group underwent review of the hospital records, a clinical examination with ECG and blood sample analysis before cardiac magnetic resonance examination of the patient. LVEF, left ventricular diastolic volume, left ventricular end systolic volume, LV mass and myocardial strain in all directions were computed. ResultsThe PP group showed a decrease in LV volume, mass and higher LVEF at follow-up (p < 0.05) while the individual response of the placebo group showed features that are seen in AR. Although there was no difference in myocardial strain, measurement for the PP-group was higher in absolute terms. ConclusionPharmacological postconditioning with mangafodipir in STEMI demonstrated cardioprotective features compared to the placebo group at follow-up. This article is protected by copyright. All rights reserved.
  •  
9.
  • Eriksson, Anders I., et al. (author)
  • Cold and warm electrons at comet 67P/Churyumov-Gerasimenko
  • 2017
  • In: Astronomy and Astrophysics. - : EDP SCIENCES S A. - 0004-6361 .- 1432-0746. ; 605
  • Journal article (peer-reviewed)abstract
    • Context. Strong electron cooling on the neutral gas in cometary comae has been predicted for a long time, but actual measurements of low electron temperature are scarce. Aims. Our aim is to demonstrate the existence of cold electrons in the inner coma of comet 67P/Churyumov-Gerasimenko and show filamentation of this plasma. Methods. In situ measurements of plasma density, electron temperature and spacecraft potential were carried out by the Rosetta Langmuir probe instrument, LAP. We also performed analytical modelling of the expanding two-temperature electron gas. Results. LAP data acquired within a few hundred km from the nucleus are dominated by a warm component with electron temperature typically 5-10 eV at all heliocentric distances covered (1.25 to 3.83 AU). A cold component, with temperature no higher than about 0.1 eV, appears in the data as short (few to few tens of seconds) pulses of high probe current, indicating local enhancement of plasma density as well as a decrease in electron temperature. These pulses first appeared around 3 AU and were seen for longer periods close to perihelion. The general pattern of pulse appearance follows that of neutral gas and plasma density. We have not identified any periods with only cold electrons present. The electron flux to Rosetta was always dominated by higher energies, driving the spacecraft potential to order -10 V. Conclusions. The warm (5-10 eV) electron population observed throughout the mission is interpreted as electrons retaining the energy they obtained when released in the ionisation process. The sometimes observed cold populations with electron temperatures below 0.1 eV verify collisional cooling in the coma. The cold electrons were only observed together with the warm population. The general appearance of the cold population appears to be consistent with a Haser-like model, implicitly supporting also the coupling of ions to the neutral gas. The expanding cold plasma is unstable, forming filaments that we observe as pulses.
  •  
10.
  • Franzén, Karin, et al. (author)
  • Validation of the Swedish version of the incontinence impact questionnaire and the urogenital distress inventory
  • 2013
  • In: Acta Obstetricia Et Gynecologica Scandinavica. - : Wiley. - 0001-6349 .- 1600-0412. ; 92:5, s. 555-561
  • Journal article (peer-reviewed)abstract
    • Objective. To validate the Swedish versions of the Incontinence Impact Questionnaire (IIQ-7) and Urogenital Distress Inventory (UDI-6). Design and setting. Prospective study, university hospital. Population and method. We analyzed reliability, validity, and responsiveness in a clinical sample of 96 women with urinary incontinence. Main outcome measures. Construct and criterion validity, reliability via test–retest and internal consistency. Responsiveness via calculation of effect size. Result. Test–retest reliability ranged from moderate to almost perfect. Cronbach's alpha was 0.39 (UDI-6) and 0.83 (IIQ-7). Effect size calculation of change after treatment demonstrated good responsiveness. The effect size at six months was moderate in the Stress Urinary Incontinence group and small in the Urge Urinary Incontinence + Mixed Urinary Incontinence group. There was a moderate to strong correlation between UDI-6 and IIQ-7 and treatment satisfaction at six, 12, and 24 months for both groups. Conclusion. The UDI-6 scale did not produce the same solid result in the psychometric analysis as the IIQ-7 scale, but these newly translated Swedish forms of UDI-6 and IIQ-7 show good responsiveness and are easy to administer and to fill out.
  •  
11.
  • Franzén, Karin, 1958-, et al. (author)
  • Validation of the Swedish version of the Incontinence Impact Questionnaire, IIQ-7 and the Urogenital Distress Inventory, UDI-6.
  • Other publication (other academic/artistic)abstract
    • Introduction and hypothesis:The purpose was to validate the Swedish versions of the Incontinence Impact Questionnaire (IIQ-7) and Urogenital Distress Inventory (UDI-6). Methods: We analyzed reliability, validity, and responsiveness in a clinical sample of 96 women with UI. Result:Test-retest reliability ranged from moderate to almost perfect. Cronbach’s alpha was 0.39 (UDI-6) and 0.83 (IIQ-7). Effect size calculation of change after treatment demonstrated good responsiveness. The effect size at 6 months was moderate in the SUI group and small in the UUI+MUI group. There was a moderate to strong correlation between UDI-6 and IIQ-7 and treatment satisfaction at 6, 12, and 24 months for both groups. ConclusionThe Swedish UDI-6 and IIQ-7 show good responsiveness and are easy to administer and fill out. UDI-6 did not produce the same solid psychometrical results as IIQ-7, but both scales can be of clinical importance and are recommended for clinical use.
  •  
12.
  • Gawel, Danuta, et al. (author)
  • A validated single-cell-based strategy to identify diagnostic and therapeutic targets in complex diseases
  • 2019
  • In: Genome Medicine. - : Springer Science and Business Media LLC. - 1756-994X. ; 11
  • Journal article (peer-reviewed)abstract
    • Background: Genomic medicine has paved the way for identifying biomarkers and therapeutically actionable targets for complex diseases, but is complicated by the involvement of thousands of variably expressed genes across multiple cell types. Single-cell RNA-sequencing study (scRNA-seq) allows the characterization of such complex changes in whole organs. Methods: The study is based on applying network tools to organize and analyze scRNA-seq data from a mouse model of arthritis and human rheumatoid arthritis, in order to find diagnostic biomarkers and therapeutic targets. Diagnostic validation studies were performed using expression profiling data and potential protein biomarkers from prospective clinical studies of 13 diseases. A candidate drug was examined by a treatment study of a mouse model of arthritis, using phenotypic, immunohistochemical, and cellular analyses as read-outs. Results: We performed the first systematic analysis of pathways, potential biomarkers, and drug targets in scRNA-seq data from a complex disease, starting with inflamed joints and lymph nodes from a mouse model of arthritis. We found the involvement of hundreds of pathways, biomarkers, and drug targets that differed greatly between cell types. Analyses of scRNA-seq and GWAS data from human rheumatoid arthritis (RA) supported a similar dispersion of pathogenic mechanisms in different cell types. Thus, systems-level approaches to prioritize biomarkers and drugs are needed. Here, we present a prioritization strategy that is based on constructing network models of disease-associated cell types and interactions using scRNA-seq data from our mouse model of arthritis, as well as human RA, which we term multicellular disease models (MCDMs). We find that the network centrality of MCDM cell types correlates with the enrichment of genes harboring genetic variants associated with RA and thus could potentially be used to prioritize cell types and genes for diagnostics and therapeutics. We validated this hypothesis in a large-scale study of patients with 13 different autoimmune, allergic, infectious, malignant, endocrine, metabolic, and cardiovascular diseases, as well as a therapeutic study of the mouse arthritis model. Conclusions: Overall, our results support that our strategy has the potential to help prioritize diagnostic and therapeutic targets in human disease.
  •  
13.
  •  
14.
  • Golub, Malgorzata, et al. (author)
  • Diel, seasonal, and inter-annual variation in carbon dioxide effluxes from lakes and reservoirs
  • 2023
  • In: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 18:3
  • Journal article (peer-reviewed)abstract
    • Accounting for temporal changes in carbon dioxide (CO2) effluxes from freshwaters remains a challenge for global and regional carbon budgets. Here, we synthesize 171 site-months of flux measurements of CO2 based on the eddy covariance method from 13 lakes and reservoirs in the Northern Hemisphere, and quantify dynamics at multiple temporal scales. We found pronounced sub-annual variability in CO2 flux at all sites. By accounting for diel variation, only 11% of site-months were net daily sinks of CO2. Annual CO2 emissions had an average of 25% (range 3%-58%) interannual variation. Similar to studies on streams, nighttime emissions regularly exceeded daytime emissions. Biophysical regulations of CO2 flux variability were delineated through mutual information analysis. Sample analysis of CO2 fluxes indicate the importance of continuous measurements. Better characterization of short- and long-term variability is necessary to understand and improve detection of temporal changes of CO2 fluxes in response to natural and anthropogenic drivers. Our results indicate that existing global lake carbon budgets relying primarily on daytime measurements yield underestimates of net emissions.
  •  
15.
  • Haghsheno, Mohammad-Ali, et al. (author)
  • Low 25-OH Vitamin D is Associated with Benign Prostatic Hyperplasia
  • 2013
  • In: Journal of Urology. - : Ovid Technologies (Wolters Kluwer Health). - 1527-3792 .- 0022-5347. ; 190:2, s. 608-614
  • Journal article (peer-reviewed)abstract
    • Purpose: We tested the hypothesis that low vitamin D is associated with benign prostatic hyperplasia. We also studied whether body composition, sex hormones, serum sex hormone-binding globulin, albumin corrected serum calcium, adiponectin and lipid status are associated with benign prostatic hyperplasia. Materials and Methods: We investigated 184 representative, randomly selected men 72 to 76 years old enrolled in the Gothenburg arm of the Osteoporotic Fractures in Men Study (MrOS). Men with a history of prostate cancer, prostate operation or medication for benign prostatic hyperplasia were excluded from study, leaving 155 available for analysis. A cross-sectional study was performed in which benign prostatic hyperplasia measured by total prostate volume was related to clinical, anthropometric, endocrine and metabolic factors on univariate and multivariate analyses with regression models. Results: Median prostate volume was 40 ml. In multivariate models only 25-OH vitamin D, albumin corrected serum calcium, serum sex hormone-binding globulin and high density lipoprotein cholesterol were significantly and inversely associated with large prostate glands. Conclusions: The current report adds 4 independent factors associated with benign prostatic hyperplasia, including low 25-OH vitamin D, serum calcium, sex hormone-binding globulin and high density lipoprotein cholesterol.
  •  
16.
  • Haghsheno, Mohammad-Ali, et al. (author)
  • Low 25-OH Vitamin D Level is Associated with Benign Prostatic Enlargement (BPE).
  • 2013
  • In: The Journal of urology. - : Ovid Technologies (Wolters Kluwer Health). - 1527-3792 .- 0022-5347. ; 190:2, s. 608-614
  • Journal article (peer-reviewed)abstract
    • PURPOSE: To test the hypothesis that low levels of vitamin D were associated with Benign Prostatic Enlargement (BPE). We also studied whether body composition, sex hormones, serum SHBG, albumin corrected serum calcium, adiponectin and lipid statuses were associated with BPE. MATERIALS AND METHODS: 184 representative randomly selected men aged 72 - 76 years, enrolled in the Gothenburg arm of the MrOs study, were investigated. Men with a medical history of prostate cancer, prostate operation or medication for BPE were excluded leaving 155 men to be analyzed. A cross-sectional study was conducted in which BPE, as measured by the total prostate gland volume, was related to clinical, anthropometric, endocrine and metabolic factors, using univariate and multivariate analyses with regression models. RESULTS: The median prostate volume was 40 ml. In multivariate models only 25-OH vitamin D, albumin corrected serum calcium, serum SHBG and HDL-cholesterol were significantly and inversely associated with large prostate glands. CONCLUSION: The present report adds four independent factors associated with BPE: Low levels of 25-OH vitamin D, serum calcium, SHBG and HDL-cholesterol.
  •  
17.
  • Haghsheno, Mohammad-Ali, et al. (author)
  • Lower urinary tract symptoms are associated with low levels of serum serotonin, high levels of adiponectin and fasting glucose, and benign prostatic enlargement.
  • 2015
  • In: Scandinavian journal of urology. - : Medical Journals Sweden AB. - 2168-1813 .- 2168-1805. ; 49:2, s. 155-161
  • Journal article (peer-reviewed)abstract
    • Abstract Objective. The aim of this study was to test whether lower urinary tract symptoms (LUTS) and urinary incontinence are associated with the metabolic syndrome (MetS). The association between LUTS and benign prostatic enlargement (BPE) was also investigated. Material and methods. A cross-sectional, representative risk factor analysis of LUTS, as measured by the International Prostate Symptom Score (IPSS), and urinary incontinence was conducted. Among 950 representative individuals, aged 69-81 years, the association between clinical, anthropometric, endocrine, metabolic and inflammatory factors on the one hand, as both major and minor aspects of MetS, and LUTS and urinary incontinence, on the other hand, was analysed. The prostate gland volume was measured in a subgroup of 155 randomly selected individuals and the association between LUTS and BPE was estimated. Results. No significant association was found between LUTS or urinary incontinence and the major aspects of the MetS. However, in a multivariate analysis, serum serotonin showed an independent negative correlation with LUTS and with urinary incontinence while fasting serum glucose and serum adiponectin showed a positive correlation with LUTS. Furthermore, in a subgroup of 155 individuals, the prostate gland volume correlated positively with LUTS. Conclusions. The study did not show an association between LUTS or urinary incontinence and the major components of the MetS. However, serum serotonin showed an independent negative correlation with LUTS and with urinary incontinence while fasting serum glucose and serum adiponectin showed a positive correlation with LUTS. The data confirm the general knowledge that BPE may be one of the causative factors of LUTS.
  •  
18.
  • Höglund, Linda, 1974-, et al. (author)
  • Energy level scheme of InAs/InxGa1-xAs/GaAs quantum-dots-in-a-well infrared photodetector structures
  • 2010
  • In: Physical Review B. Condensed Matter and Materials Physics. - Woodbury, NY : American Physical Society. - 1098-0121 .- 1550-235X. ; 82:3, s. 035314-
  • Journal article (peer-reviewed)abstract
    • A thorough investigation of quantum-dots-in-a-well structures for infrared photodetector applications has been performed employing different experimental techniques. The electronic structure of self-assembled InAs quantum dots embedded in an In0.15Ga0.85As/GaAs quantum well (QW) was deduced from photoluminescence (PL) and PL excitation (PLE) spectroscopy. From polarization-dependent PL it was revealed that the quantum dots hold two electron energy levels and two heavy-hole levels. Tunnel capacitance spectroscopy confirmed an electron energy level separation of about 50 meV, and additionally, that the conduction-band ground state and excited state of the dots are twofold and fourfold degenerates, respectively. Intersubband photocurrent spectroscopy, combined with simultaneous interband pumping of the dots, revealed a dominant transition at 150 meV (8.5 mu m) between the ground state of the quantum dots and the excited state of the QW. Results from detailed full three-dimensional calculations of the electronic structure, including effects of composition intermixing and interdot interactions, confirm the experimentally unravelled energy level scheme of the dots and well.
  •  
19.
  • Karlsson, Fredrik, 1975-, et al. (author)
  • Articulatory closure proficiency in Parkinson's disease patients following deep brain stimulation of the subthalamic nucleus and caudal zona incerta.
  • 2014
  • In: Journal of Speech, Language and Hearing Research. - 1092-4388 .- 1558-9102. ; 57, s. 1178-1190
  • Journal article (peer-reviewed)abstract
    • OBJECTIVEThe present study aimed at comparing the effects of deep brain stimulation (DBS) treatment of the subthalamic nucleus (STN) and the caudal zona incerta (cZi) on Parkinson's disease patients' proficiency in achieving oral closure and release during plosive production. METHODS Nineteen patients were evaluated preoperatively and 12 months after DBS surgery. Nine patients were implanted in the STN, seven bilaterally and two unilaterally (left). Ten were bilaterally implanted in the cZi. Postoperative examinations were made off and on stimulation. All patients received simultaneous L-dopa treatment in all conditions. For a series of plosives extracted from a reading passage, absolute and relative measures of duration of frication and amplitude of plosive release were compared between conditions within each treatment group. RESULTS Relative duration of frication increased in voiceless plosives in the on stimulation condition in cZi patients. Similar trends were observed across the data set. Duration of pre-release frication and the release peak prominence increased in voiceless plosives on stimulation for both groups. CONCLUSIONS The increased release prominence suggests that patients achieved a stronger closure gesture due to DBS, but that the increased energy available resulted in increased frication.
  •  
20.
  • Karlsson, Fredrik, 1975-, et al. (author)
  • Control of phonatory onset and offset in Parkinson patients following deep brain stimulation of the subthalamic nucleus and caudal Zona Incerta
  • 2012
  • In: Parkinsonism & Related Disorders. - : Elsevier. - 1353-8020 .- 1873-5126. ; 18:7, s. 824-827
  • Journal article (peer-reviewed)abstract
    • Laryngeal hypokinesia is a common symptom in Parkinson’s disease (PD) that affects quality of life. Deep brain stimulation (DBS) is well recognized as a complementary method for treatment of motor symptoms in PD but the outcomes on patients’ control over phonatory alternation have yet not been clearly elucidated. The present study examined the effect of subthalamic nucleus STN-DBS (n=8, aged 51-72 yrs; median=63 yrs) and caudal Zona incerta cZi-DBS (n=8,aged 49-71 yrs; median=61 yrs) on control of onset and offset of phonation in connected speech. The patients were evaluated in a preoperatively (Med ON, 1.5 times the ordinary Levodopa dose) and 12 months postoperatively (Med ON, ordinary Levodopa dose). The results provided evidence of a progressive reduction in the ability to manifest alternations between voicing and voiceless states in a reading task. Mean proportion produced with inappropriate voicing increased from 47.6% to 55.3% and from 62.9% to 68.6% of the total duration for the two groups of patients between Pre-op and Post-op, Stim OFF evaluations. The medial and final parts of the fricative were more affected than the initial part, indicating an increased voicing lead into the following vowel. We propose that this reduction in phonatory control is be due to either progression of the disease, an effect of reduced Levodopa dosage or a microlesional effect. Patients’ proficiency in alternating between voiced and voiceless states in connected speech remained unaffected by both STN-DBS and cZi-DBS.
  •  
21.
  • Karlsson, Fredrik, 1975-, et al. (author)
  • Deep brain stimulation of caudal zona incerta and subthalamic nucleus in patients with Parkinson’s disease : effects on diadochokinetic rate
  • 2011
  • In: Parkinson's Disease. - : Hindawi Publishing Corporation. - 2090-8083 .- 2042-0080. ; 2011, s. 605607-
  • Journal article (peer-reviewed)abstract
    • The hypokinetic dysarthria observed in Parkinson's disease (PD) affects the range, speed, and accuracy of articulatory gestures in patients, reducing the perceived quality of speech acoustic output in continuous speech. Deep brain stimulation (DBS) of the subthalamic nucleus (STN-DBS) and of the caudal zona incerta (cZi-DBS) are current surgical treatment options for PD. This study aimed at investigating the outcome of STN-DBS (7 patients) and cZi-DBS (7 patients) in two articulatory diadochokinesis tasks (AMR and SMR) using measurements of articulation rate and quality of the plosive consonants (using the percent measurable VOT metric). The results indicate that patients receiving STN-DBS increased in articulation rate in the Stim-ON condition in the AMR task only, with no effect on production quality. Patients receiving cZi-DBS decreased in articulation rate in the Stim-ON condition and further showed a reduction in production quality. The data therefore suggest that cZi-DBS is more detrimental for extended articulatory movements than STN-DBS.
  •  
22.
  • Karlsson, Jan-Erik, et al. (author)
  • Ambulatory ST-recording has no additional value to exercise test for identification of severe coronary lesions after an episode of unstable coronary artery disease in men
  • 1993
  • In: International Journal of Cardiac Imaging. - : Wolters Kluwer. - 0167-9899. ; 9:4, s. 281-289
  • Journal article (peer-reviewed)abstract
    • One month after an episode of unstable coronary artery disease, 95 male patients performed coronary angiography, 48 hours ambulatory ST-recording and also an exercise test. ST-depression occurred in 29.5% during the ST-recording and in 44.2% during the exercise test (p<0.05). In patients with ST-depression at ambulatory monitoring, 79% demonstrated the same finding at the exercise test. A high risk response at the exercise test - defined as either ST-depression in ≥ 3 leads, ST-depression in 1-2 leads with a maximal work load below the 60th percentile or a maximal work load below the 30th percentile regardless of the ECG reaction - occurred in 56.8%. Severe coronary lesions - defined as three vessel disease, left main stenosis or proximal left anterior descending artery stenosis as part of two vessel disease - was observed in 46.3%. Patents with a high risk exercise test response and patients with ST-depression during ST-recording had severe coronary lesions in 67% and 64% respectively. However, a high risk exercise test response occurred in 82%, while ST-depression at ambulatory monitoring was observed only in 41% of the patients with severe coronary lesions (p < 0.001). Thus, ambulatory ST-recording one month after an episode of unstable coronary artery disease in men adds no further information to a symptom limited exercise test in order to identify patients with severe coronary lesions.
  •  
23.
  • Karlsson, Jan-Erik, et al. (author)
  • Mangafodipir as a cardioprotective adjunct to reperfusion therapy: a feasibility study in patients with ST-segment elevation myocardial infarction
  • 2015
  • In: European Heart Journal - Cardiovascular Pharmacotherapy. - : European Society of Cardiology. - 2055-6837 .- 2055-6845. ; 1:1, s. 39-45
  • Journal article (peer-reviewed)abstract
    • Aims The aim of the present study was to examine the feasibility of applying the catalytic antioxidant mangafodipir [MnDPDP, manganese (Mn) dipyridoxyl diphosphate] as a cardioprotective adjunct to primary percutaneous coronary intervention (pPCI) in patients with ST-segment elevation (STE) myocardial infarction (STEMI). Both MnDPDP and a metabolite (Mn dipyridoxyl ethyldiamine) possess properties as mitochondrial superoxide dismutase mimetics and iron chelators, and combat oxidative stress in various tissues and conditions.Methods and resultsThe study tested MnDPDP (n ¼ 10) vs. saline placebo (n ¼ 10), given as a brief intravenous (i.v.) infusion prior to balloon inflation during pPCI in patients with STEMI. Mangafodipir waswell tolerated and did not affect heart rate or blood pressure. Despite longer ischaemic time (205 vs. 144 min, P ¼ 0.019) in theMnDPDPgroup, plasma biomarker releaseswere identical for the two groups. With placebo vs.MnDPDP, mean STE resolutions were 69.8 vs. 81.9% (P ¼ 0.224) at 6 h and 73.1 vs. 84.3% (P ¼ 0.077) at 48 h. Cardiac magnetic resonance revealed mean infarct sizes of 32.5 vs. 26.2% (P ¼ 0.406) andmeanleft ventricular (LV) ejection fractions of 41.8 vs. 47.7% (P ¼ 0.617) with placebovs.MnDPDP.More LVthrombi were detected in placebo hearts (5 of 8) than MnDPDP-treated hearts (1 of 10; P ¼ 0.011).Conclusions Mangafodipir is a safe drug for use as an adjunct to reperfusion therapy. A tendency to benefit of MnDPDP needs confirmation in a larger population. The study revealed important information for the design of a Phase II trial. 
  •  
24.
  • Karlsson, Sofia, 1982, et al. (author)
  • A Laboratory Study of the in Situ Sulfation of Alkali Chloride Rich Deposits: Corrosion Perspective
  • 2016
  • In: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 30:9, s. 7256-7267
  • Journal article (peer-reviewed)abstract
    • The initial corrosive effect of small (1.35 mu mol/cm(2)) and large (13.5 mu mol/cm(2)) amounts of KCl on 304L has been investigated. The investigations were performed in both the absence and presence of 300 ppm of SO2 at 600 degrees C. The results showed that in the absence of SO2 KCl accelerates the rate of corrosion by means of two types of corrosion attack: a general attack and a steel grain boundary attack. The general attack has been proved to be initiated by K2CrO4 formation. Meanwhile, the steel grain boundary attack is suggested to be accelerated by HCl released due to the chromate formation which increased with higher amounts of KCl. The presence of KCl and SO2 resulted in the simultaneous formation of K2SO4 and K2CrO4. The chromate formation resulted in a general corrosion attack. However, the oxide growth was significantly reduced due to the very fast sulfation reaction. In contrast, the steel grain boundary attack increased in the presence of SO2. It is suggested that the attack is accelerated by HCl released from the sulfation reaction and by sulfidation of the steel grain boundaries.
  •  
25.
  • Källhammer, Jan-Erik, 1960-, et al. (author)
  • Shouldn't cars react as drivers expect?
  • 2007
  • In: PROCEEDINGS of the Fourth International Driving Symposium on Human Factors in Driver Assessment, Training and Vehicle Design. - Iowa City, Iowa : Public Policy Center, University of Iowa.
  • Conference paper (peer-reviewed)abstract
    • The objective of this project is to develop and test a multi-method empirical approach for predicting drivers- assessments of the level of acceptability of a warning issued in response to accidents, near-accidents, and other incidents. The role of humans (drivers) in the pre-crash phase means that systems that protect occupants and pedestrians must be seen as distributed, cognitive systems. Driver acceptance therefore has to be an important design goal. One obstacle to acceptance is the human dislike for false alarms. An approach to overcoming driver dislike for false alarms is to focus on driver expectations and to design systems to issue alarms when and only when the driver is likely to accept them. In this paper we discuss one such approach.
  •  
Skapa referenser, mejla, bekava och länka
  • Result 1-25 of 218
Type of publication
journal article (167)
conference paper (22)
other publication (9)
reports (8)
doctoral thesis (6)
research review (3)
show more...
licentiate thesis (3)
show less...
Type of content
peer-reviewed (177)
other academic/artistic (40)
pop. science, debate, etc. (1)
Author/Editor
Karlsson, Jan-Erik (49)
Karlsson, Jan (18)
Rubensson, Jan-Erik (12)
Karlsson, Jan-Erik, ... (11)
Järvholm, Kajsa (10)
Flodmark, Carl-Erik (10)
show more...
Damber, Jan-Erik, 19 ... (9)
Marcus, Claude (9)
Rosengren, Lars, 195 ... (8)
Karlsson, Leif (8)
Rentzos, Alexandros, ... (8)
Bäckvall, Jan-E. (8)
Peltonen, Markku (8)
Giesler, Reiner (8)
Karlsson, Fredrik (7)
Johnston, Eric V. (7)
Fridlund, Bengt (7)
Svensson, Jan-Erik, ... (7)
Olbers, Torsten (7)
Karlsson, Jan, 1974- (7)
Karlsson, Jan, 1950 (7)
Karlsson, Erik A. (7)
Karlsson, Sofia, 198 ... (7)
Åkermark, Björn (6)
Widmark, Anders (6)
Blomstedt, Patric (6)
Linder, Jan (6)
Alfredsson, Joakim (6)
Feifel, Raimund (6)
Dahlgren, Jovanna (6)
Thellenberg-Karlsson ... (6)
Hedin, Lage (6)
Blomqvist, Lennart (6)
Liske, Jesper, 1978 (6)
Nordh, Erik (6)
Geibrink, Erik (6)
Gronowitz, Eva (6)
Karlsson, Magnus (5)
Bergh, Anders (5)
Ohlsson, Claes, 1965 (5)
Sundberg, Jan (5)
Neovius, Martin (5)
Mellström, Dan, 1945 (5)
Malm, Dan, 1954- (5)
Jonsson, Torbjörn, 1 ... (5)
Karlsson, Jan-Erik, ... (5)
Haghsheno, Mohammad- ... (5)
Löwhagen Hendén, Pia (5)
Karlsson, Fredrik, 1 ... (5)
Olofsson, Katarina (5)
show less...
University
Linköping University (57)
Lund University (44)
University of Gothenburg (39)
Uppsala University (39)
Umeå University (38)
Karolinska Institutet (29)
show more...
Stockholm University (19)
Jönköping University (19)
Chalmers University of Technology (16)
Örebro University (13)
Royal Institute of Technology (11)
RISE (9)
Linnaeus University (7)
Halmstad University (6)
Luleå University of Technology (4)
Mälardalen University (3)
University of Borås (3)
Swedish University of Agricultural Sciences (3)
Kristianstad University College (2)
Karlstad University (2)
University West (1)
Stockholm School of Economics (1)
Mid Sweden University (1)
University of Skövde (1)
Swedish Agency for Marine and Water Management (1)
show less...
Language
English (206)
Swedish (12)
Research subject (UKÄ/SCB)
Medical and Health Sciences (110)
Natural sciences (64)
Engineering and Technology (22)
Social Sciences (13)
Agricultural Sciences (1)

Year

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Close

Copy and save the link in order to return to this view