| 1. |
- Asplund Persson, Anna, 1966-, et al.
(author)
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Cross-talk between adenosine and the oxatriazole derivative GEA 3175 in platelets
- 2005
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In: European Journal of Pharmacology. - : Elsevier BV. - 0014-2999 .- 1879-0712. ; 517:3, s. 149-157
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Journal article (peer-reviewed)abstract
- We examined the interplay between adenosine and the nitric oxide (NO)-containing oxatriazole derivative GEA 3175 in human platelets. The importance of cyclic guanosine 3′5′-monophosphate (cGMP)-inhibited phosphodiesterases (PDEs) was elucidated by treating the platelets with adenosine combined with either GEA 3175 or the PDE3-inhibitor milrinone. The drug combinations provoked similar cyclic adenosine 3′5′-monophosphate (cAMP) responses. On the contrary, cGMP levels were increased only in GEA 3175-treated platelets. Both drug combinations reduced P-selectin exposure, platelet adhesion and fibrinogen-binding. However, adenosine together with GEA 3175 was more effective in inhibiting platelet aggregation and ATP release. Thrombin-induced rises in cytosolic Ca2+ were suppressed by the two drug combinations. Adenosine administered with GEA 3175 was, however, more effective in reducing Ca2+ influx.In conclusion, the interaction between adenosine and GEA 3175 involves cGMP-mediated inhibition of PDE3. The results also imply that inhibition of Ca2+ influx represent another cGMP-specific mechanism that enhances the effect of adenosine.
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| 2. |
- Asplund Persson, Anna, 1966-, et al.
(author)
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Dual actions of dephostatin on the nitric oxide/cGMP-signalling pathway in porcine iliac arteries
- 2005
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In: European Journal of Pharmacology. - : Elsevier BV. - 0014-2999 .- 1879-0712. ; 521:1-3, s. 124-132
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Journal article (peer-reviewed)abstract
- We examined the effects of the nitrosoamine dephostatin on the nitric oxide (NO)/cyclic guanosine 3′,5′-monophosphate (cGMP)-signalling in porcine iliac arteries. Dephostatin has been characterised as a tyrosine phosphatase inhibitor, but Western blot analyses showed that dephostatin did not augment tyrosine phosphorylation of arterial proteins. However, dephostatin relaxed pre-contracted arteries, and this effect was antagonised by the soluble guanylyl cyclase inhibitor 1H[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). Furthermore, dephostatin increased the cGMP content and the serine phosphorylation of vasodilator-stimulated phosphoprotein. Dephostatin also inhibited the relaxation induced by acetylcholine and the NO-donor S-nitroso-N-acetyl-penicillamine (SNAP). In contrast, dephostatin did not affect the NO-dependent actions of 1,2,3,4-Oxatriazolium, 3-(3-chloro-2-metylphenyl)-5-[[(4methylphenyl)sulfonyl]amino]-hydroxide inner salt (GEA 3175). Measurement of NO revealed that dephostatin accelerated the consumption of NO. In conclusion, dephostatin exerts dual effects on the NO/cGMP-signalling pathway in iliac arteries. The drug actions included scavenging of NO, but also stimulation of cGMP production. These effects were not related to inhibition of tyrosine phosphatases.
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| 3. |
- Bengtsson, Karin, 1980, et al.
(author)
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Are ankylosing spondylitis, psoriatic arthritis and undifferentiated spondyloarthritis associated with an increased risk of cardiovascular events? A prospective nationwide population-based cohort study
- 2017
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In: Arthritis Research and Therapy. - : Springer Science and Business Media LLC. - 1478-6354 .- 1478-6362. ; 19:1
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Journal article (peer-reviewed)abstract
- Background: To investigate the risk of first-time acute coronary syndrome (ACS), stroke and venous thromboembolism (VTE) in patients with ankylosing spondylitis (AS), psoriatic arthritis (PsA) and undifferentiated spondyloarthritis (uSpA), compared to each other and to the general population (GP). Methods: This is a prospective nationwide cohort study. Cohorts with AS (n = 6448), PsA (n = 16,063) and uSpA (n = 5190) patients and a GP (n = 266,435) cohort, were identified 2001-2009 in the Swedish National Patient and Population registers. The follow-up began 1 January 2006, or 6 months after the first registered spondyloarthritis (SpA) diagnosis thereafter, and ended at ACS/stroke/VTE event, death, emigration or 31 December 2012. Crude and age- and sex-standardized incidence rates (SIRs) and hazard ratios (HRs) were calculated for incident ACS, stroke or VTE, respectively. Results: Standardized to the GP cohort, SIRs for ACS were 4.3, 5.4 and 4.7 events per 1000 person-years at risk in the AS, PsA and uSpA cohort, respectively, compared to 3.2 in the GP cohort. SIRs for stroke were 5.4, 5.9 and 5.7 events per 1000 person-years at risk in the AS, PsA and uSpA cohort compared to 4.7 in the GP cohort. Corresponding SIRs for VTE were 3.6, 3.2 and 3.5 events per 1000 person-years at risk compared to 2.2 in the GP cohort. Age-and sex-adjusted HRs (95% CI) for ACS events were significantly increased in AS (1.54 (1.31-1.82)), PsA (1.76 (1.59-1.95)) and uSpA (1.36 (1.05-1.76)) compared to GP. Age-adjusted HRs for ACS was significantly decreased in female AS patients (0.59 (0.37-0.97)) compared to female PsA patients. Age-and sex-adjusted HRs for stroke events were significantly increased in AS (1.25 (1.06-1.48)) and PsA (1.34 (1.22-1.48)), and nonsignificantly increased in uSpA (1.16 (0.91-1.47)) compared to GP. For VTE the age-and sex-adjusted HRs for AS, PsA and uSpA were equally and significantly increased with about 50% compared to GP. Conclusions: Patients with AS, PsA and uSpA are at increased risk for ACS and stroke events, which emphasizes the importance of identification of and intervention against cardiovascular risk factors in SpA patients. Increased alertness for VTE is warranted in patients with SpA.
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| 4. |
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| 5. |
- Bengtsson, Karin, 1980, et al.
(author)
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Incidence of extra-articular manifestations in ankylosing spondylitis, psoriatic arthritis and undifferentiated spondyloarthritis : Results from a national register-based cohort study
- 2021
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In: Rheumatology (United Kingdom). - : Oxford University Press (OUP). - 1462-0324 .- 1462-0332. ; 60:6, s. 2725-2734
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Journal article (peer-reviewed)abstract
- Objectives: To estimate the incidence and strength of association of extra-articular manifestations [EAMs, here: anterior uveitis (AU), IBD and psoriasis] in patients with AS, undifferentiated SpA (uSpA) and PsA, compared with controls. Methods: Three mutually exclusive cohorts of patients aged 18-69 years with AS (n = 8517), uSpA (n = 10 245) and PsA (n = 22 667) were identified in the Swedish National Patient Register 2001-2015. Age-, sex- and geography-matched controls were identified from the Swedish Population Register. Follow-up began 1 January 2006, or six months after the first SpA diagnosis, whichever occurred later, and ended at the first date of the EAM under study, death, emigration, 70 years of age, and 31 December 2016. Incidence rates (IRs) and incidence rate ratios were calculated for each EAM, and stratified by sex and age. Results: Incidence rate ratios for incident AU, IBD and psoriasis were significantly increased in AS (20.2, 6.2, 2.5), uSpA (13.6, 5.7, 3.8) and PsA (2.5, 2.3, n.a) vs controls. Men with AS and uSpA had significantly higher IRs per 1000 person-years at risk for incident AU than women with AS (IR 15.8 vs 11.2) and uSpA (IR 10.1 vs 6.0), whereas no such sex difference was demonstrated in PsA or for the other EAMs. Conclusions: AU, followed by IBD and psoriasis, is the EAM most strongly associated with AS and uSpA. Among the SpA subtypes, AS and uSpA display a largely similar pattern of EAMs, whereas PsA has a considerably weaker association with AU and IBD.
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| 6. |
- Berg, Cecilia, 1976-, et al.
(author)
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Platelet-induced growth of human fibroblasts is associated with an increased expression of 5-lipoxygenase
- 2006
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In: Thrombosis and Haemostasis. - 0340-6245 .- 2567-689X. ; 96:5, s. 652-659
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Journal article (peer-reviewed)abstract
- Proliferation of fibroblasts is vital for adequate wound healing but is probably also involved in different hyperproliferative disorders such as atherosclerosis and cancer. The regeneration of tissue usually starts with coagulation, involving release of mitogenic and inflammatory factors from activated platelets. This study focuses on the role of eicosanoids in the proliferative effects of platelets on human fibroblasts. We show that the phospholipase A2 inhibitor 7,7-dimethyl-5,8-eicosadienoic acid (DMDA), the combined cyclooxygenase (COX) and lipoxygenase (LOX) inhibitor 5,8,11,14-eicosatetraynoic acid (ETYA) and the LOX inhibitor 5,8,11-eicosatriynoic acid (ETI) block the platelet-induced proliferation of serum starved subconfluent human fibroblasts. Anti-proliferative effects were also obtained by specific inhibition of 5-LOX with 5,6-dehydro arachidonic acid (5,6-dAA), whereas the 12-LOX inhibitor cinnamyl-3,4-dihydroxy-α-cyanocinnamate (CDC) did not affect the platelet-stimulated growth of fibroblasts. The expression of 5-LOX was analyzed by reverse-transcriptase-mediated PCR (RT-PCR), Western blotting and HPLC. 5-LOX message and protein was detected in fibroblasts but not in platelets. Incubation with platelets markedly increased, already after one hour, the expression of 5-LOX in the fibroblast culture. The increased 5-LOX activity was associated with an elevated level of the 5-LOX metabolite 5-hydroxyeicosatetraenoic acid (5-HETE) reaching its maximum after 1-2 hours of co-incubation of fibroblasts and platelets. The 5-HETE production was reduced by the inhibitors DMDA, ETYA and ETI. In conclusion, this study suggests that platelet-stimulated proliferation of fibroblasts is mediated by an increased 5-LOX activity, which supports recent findings indicating a crucial role for this enzyme in proliferative disorders such as atherosclerosis. © 2006 Schattauer GmbH, Stuttgart.
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| 7. |
- Bower, H., et al.
(author)
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Effects of the COVID-19 pandemic on patients with inflammatory joint diseases in Sweden: from infection severity to impact on care provision
- 2021
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In: Rmd Open. - : BMJ. - 2056-5933. ; 7:3
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Journal article (peer-reviewed)abstract
- Objectives To compare risks for COVID-19-related outcomes in inflammatory joint diseases (IJDs) and across disease-modifying antirheumatic drugs (DMARDs) during the first two waves of the pandemic and to assess effects of the pandemic on rheumatology care provision. Methods Through nationwide multiregister linkages and cohort study design, we defined IJD and DMARD use annually in 2015-2020. We assessed absolute and relative risks of hospitalisation or death listing COVID-19. We also assessed the incidence of IJD and among individuals with IJD, rheumatologist visits, DMARD use and incidence of selected comorbidities. Results Based on 115 317 patients with IJD in 2020, crude risks of hospitalisation and death listing COVID-19 (0.94% and 0.33% across both waves, respectively) were similar during both waves (adjusted HR versus the general population 1.33, 95% CI 1.23 to 1.43, for hospitalisation listing COVID-19; 1.23, 95% CI 1.08 to 1.40 for death listing COVID-19). Overall, biological disease-modifying antirheumatic drugs (bDMARDs)/targeted synthetic disease-modifying antirheumatic drugs (tsDMARDs) did not increase risks of COVID-19 related hospitalisation (with the exception of a potential signal for JAK inhibitors) or death. During the pandemic, decreases were observed for IJD incidence (-7%), visits to rheumatology units (-16%), DMARD dispensations (+6.5% for bDMARD/tsDMARDs and -8.5% for conventional synthetic DMARDs compared with previous years) and for new comorbid conditions, but several of these changes were part of underlying secular trends. Conclusions Patients with IJD are at increased risk of serious COVID-19 outcomes, which may partially be explained by medical conditions other than IJD per se. The SARS-CoV-2 pandemic has exerted measurable effects on aspects of rheumatology care provision demonstrated, the future impact of which will need to be assessed.
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| 8. |
- Bower, Hannah, et al.
(author)
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Impact of the COVID-19 pandemic on morbidity and mortality in patients with inflammatory joint diseases and in the general population : a nationwide Swedish cohort study
- 2021
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In: Annals of the Rheumatic Diseases. - : BMJ Publishing Group Ltd. - 0003-4967 .- 1468-2060. ; 80:8, s. 1086-1093
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Journal article (peer-reviewed)abstract
- Objectives: To estimate absolute and relative risks for all-cause mortality and for severe COVID-19 in inflammatory joint diseases (IJDs) and with antirheumatic therapies.Methods: Through Swedish nationwide multiregister linkages, we selected all adult patients with rheumatoid arthritis (RA, n=53 455 in March 2020), other IJDs (here: spondyloarthropathies, psoriatic arthritis and juvenile idiopathic arthritis, n=57 112), their antirheumatic drug use, and individually matched population referents. We compared annual all-cause mortality March-September 2015 through 2020 within and across cohorts, and assessed absolute and relative risks for hospitalisation, admission to intensive care and death due to COVID-19 March-September 2020, using Cox regression.Results: During March-September 2020, the absolute all-cause mortality in RA and in other IJDs was higher than 2015-2019, but relative risks versus the general population (around 2 and 1.5) remained similar during 2020 compared with 2015-2019. Among patients with IJD, the risks of hospitalisation (0.5% vs 0.3% in their population referents), admission to intensive care (0.04% vs 0.03%) and death (0.10% vs 0.07%) due to COVID-19 were low. Antirheumatic drugs were not associated with increased risk of serious COVID-19 outcomes, although for certain drugs, precision was limited.Conclusions: Risks of severe COVID-19-related outcomes were increased among patients with IJDs, but risk increases were also seen for non-COVID-19 morbidity. Overall absolute and excess risks are low and the level of risk increases are largely proportionate to those in the general population, and explained by comorbidities. With possible exceptions, antirheumatic drugs do not have a major impact on these risks.
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| 9. |
- Frisell, T., et al.
(author)
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Safety of biological and targeted synthetic disease-modifying antirheumatic drugs for rheumatoid arthritis as used in clinical practice: results from the ARTIS programme
- 2023
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In: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 82:5
-
Journal article (peer-reviewed)abstract
- ObjectiveLongitudinal clinical registry-infrastructures such as Anti-Rheumatic Therapies in Sweden (ARTIS) allow simultaneous comparison of the safety of individual immunomodulatory drugs used in clinical practice, with consistent definitions of treatment cohorts, follow-up and outcomes. Our objective was to assess and compare incidence rates of key safety outcomes for individual targeted synthetic or biological disease-modifying antirheumatic drugs (b/ts DMARDs) in rheumatoid arthritis (RA), updating previous reports and including newer treatments including Janus Kinase inhibitors (JAKi). MethodsNationwide register-based cohort study including all patients with RA in Sweden registered as starting any b/tsDMARD 1 January 2010 through 31 December 2020, followed until 30 June 2021 (N=20 117). The incidence rates of selected outcomes, identified through national healthcare registers, were compared between individual b/tsDMARDs, adjusted for confounding by demographics, RA disease characteristics and comorbidity. ResultsThere were marked differences in treatment discontinuations due to adverse events (rates per 1000 person-years ranged from 18 on rituximab to 57 on tofacitinib), but few significant differences were observed for the serious adverse events under study. Neither cardiovascular events nor general serious infections were more frequent on baricitinib or tofacitinib versus bDMARDs, but JAKi were associated with higher rates of hospital-treated herpes zoster (HR vs etanercept, 3.82 (95% CI 2.05 to 7.09) and 4.00 (1.59 to 10.06)). Low number of events limited some comparisons, in particular for sarilumab and tofacitinib. ConclusionData from ARTIS supports that the b/tsDMARDs currently used to treat RA have acceptable and largely similar safety profiles, but differences exist in particular concerning tolerability and specific infection risks.
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| 10. |
- Johansson, Fredrik, 1968-, et al.
(author)
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An indomethacin-sensitive contraction induced by β-antagonists in guinea pig airways
- 2004
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In: Canadian Journal of Physiology and Pharmacology. - : Canadian Science Publishing. - 0008-4212 .- 1205-7541. ; 82:6, s. 393-401
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Journal article (peer-reviewed)abstract
- β-adrenergic receptor (β-AR) antagonists have been associated with increased airway reactivity in asthmatics and potentiation of contractile stimuli in animal models. In the present study, using an in vitro model of tracheal preparations from guinea pigs, we show that the β-AR antagonists propranolol and pindolol induce a smooth muscle contraction. A prerequisite for this contraction is that the airway preparations have been pre-treated with an β-AR agonist. Our data show that the contractile effect of β-AR antagonists is not a simple consequence of reversing the agonist-induced relaxation. Furthermore, the effect seems to be mediated through interaction with β2-ARs since the response is stereo-selective, and the selective β1-AR receptor antagonist atenolol did not induce any contractile response. SQ 29,546, a thromboxane A2 antagonist; MK 886, a lipoxygenase inhibitor; and indomethacin, a cyclooxygenase inhibitor significantly inhibited the contractions of the tracheal preparations induced with propranolol or pindolol. We put forward the hypothesis that the contractile effect of the β-AR antagonist is a consequence of their inverse agonist activity, which is only evident when the receptor population have a higher basal activity. Our results indicate a novel additional explanation for the known side effect, bronchoconstriction, of β-AR antagonist.Key words: beta antagonist, guinea pig trachea, propranolol, formoterol, pindolol, indomethacin.
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| 11. |
- Langenheder, Silke, et al.
(author)
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Growth dynamics within bacterial communities in riverine and estuarine batch cultures
- 2004
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In: Aquatic Microbial Ecology. - : Inter-Research Science Center. - 0948-3055 .- 1616-1564. ; 37, s. 137-148
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Journal article (peer-reviewed)abstract
- We investigated temporal changes in community composition of bacteria growing on riverine dissolved organic carbon. Batch cultures were adjusted to riverine or estuarine salinity levels and inoculated with bacteria from these 2 environments to test whether growth patterns of bacterial taxa are influenced by salinity and/or the source of the inoculum. Changes in bacterial community composition at different stages of the growth phase were studied by 16S rDNA denaturing gradient gel electrophoresis (DGGE). Furthermore, the growth dynamics of 7 bacteria previously isolated from the estuary were followed by quantitative DNA-DNA hybridization. Growth dynamics within bacterial communities were significantly influenced by the source of the inoculum but not by salinity, suggesting that slight changes in salinity, to which riverine bacteria are exposed when discharged into the Northern Baltic Sea, are not a major regulating factor of community dynamics. Additionally, our results indicated only minor differences in the appearance and growth of bacteria when examined by quantitative DNA-DNA hybridization, whereas DGGE banding patterns suggested that there were fast- and slow-growing types of bacteria.
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| 12. |
- Lindström, Eva G., 1961-
(author)
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Regulation of experimentally induced airway obstruction
- 1998
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Doctoral thesis (other academic/artistic)abstract
- Asthma is one of the commonest diseases in industrialized countries. The cause and mechanisms of !he disorder are still not fully unden;tood, al!hough it is known that inflammation in !he airways plays an important role. Inflammatory mediators, e.g. leukotrienes, prostaglandins, histamine and bradykinin, are all possible acton; in !he asthmatic condition. Moreover, disturbance in !he neurogenic system has been discussed: the cholinergic, adrenergic, and nonadrenergic noncholinergic systems may influence the airway tone. Structural changes in !he airways of as!hmatics, e.g. epithelial damage, have also been observed. The consequence of epithelial damage is not fully understood, but it is clear that the epithelial layer can act as a physical and metabolic barrier.In the present research, we developed an in vitro model for detenninadon of airway smooth muscle tension and concomitant mediator release in guinea pig airways. This method also allows manipulation of the airway epithelium. We found !he condition of !he airway epithelium to be of great significance for smooth muscle response and mediator release. An intact epithelium acted as a powerful barrier; removal of the epithelium resulted in increased responses to histamine, acetylcholine and potassium ions. An intact epithelial layer was also important for leukotriene and prostaglandin production, whereas in !he absence of epithelium, antigen-induced contractions were almost completely dependent on histamine.Sensory nerve activation provoked by electrical field stimulation (EFS), capsaicin (CAP) and antigen-induced mediators was investigated by analyzing !he amount of neurokinin A-like immunoreactivity (NKA-Ll). Multiple agents were shown to regulate this release. EFSinduced outflow of NKA-LI was powerfully decreased by morphine, and !his reduction was not reversed by naloxone. In contrast, the inhibition obtained upon CAP-challenge was reven;ible. These results may imply !hat EFS also activates endugenous inhibitory systems.Antigen challenge of epithelial-denuded bronchial tube preparations resulted in contractions and concomitant release of histamine and tachykinins. Exposure to pyrilamine (a histamine H 1 receptor antagonist) and icatibant (a bradykinin B2 receptor antagonist) markedly depressed !he NKA-LI outflow. Furthermore, pyrilamine significantly reduced !he basal outflow of NKA-LI and antigen-induced contractions, while icatibant did not. These results show that, among !he mediators released in response to antigen-challenge, histamine and bradykinin are able to modulate both the outflow of tachykinins and contractile responses.The long-acting 132 receptor agonist formoterol was characterized with regard to relaxing properties and effects on tachykinin and histamine release. The RR enantiomer was most potent in relaxing tracheal preparations, followed by racemic and SS-formoterol. Formoterol also reduced the antigen-induced outflow of NKA-LI. RR-formoterol also lowered both CAPand EFS-induced NKA-LI outflow but not histamine release. These results indicate that, in addition to its ability to directly relax smooth muscle, formoterol may decrease the responses of airway tissue to antigen by inhibiting mediator release from sensory neurons, probably through direct interaction with sensory neurones.In summary, we have developed a method for determination of epithelial inlluence, mediator release and smooth muscle contraction in guinea pig airways. We have shown that antigen-challenge release inflammatory mediators and activates sensory neurons. Both histamine and bradykinin are involved in the regulation of the tackykinin release. It was also shown that formoterol reduoed NKA-LI outflow.
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| 13. |
- Lindström, Jan
(author)
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Radioluminescence : A simple model for fluorescent layers - analysis and applications
- 2021
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Doctoral thesis (other academic/artistic)abstract
- A phosphor or scintillator is a material that will emit visible light when struck by ionising radiation. In the early days of diagnostic radiology, it was discovered that the radiation dose needed to get an image on a film, could be greatly reduced by inserting a fluorescent layer of a phosphor in direct contact with the film. Thus, introducing the step of converting the ionising radiation to light in a first step. Going forward in time, film has been replaced with photodetectors and there is now a variety of imaging x-ray systems, still based on phosphors and scintillators. There is continuous research going on to optimise between the radiation dose needed and a sufficient image quality. These factors tend to be in opposition to each other. It is a complicated task to optimise these imaging system and new phosphor materials emerges regularly. One of the key factors is the efficiency of the conversion from xrays to light. In this work this is denoted “extrinsic efficiency”. It is important since it largely determines the final dose to the patient needed for the imaging task. Most imaging x-ray detectors are based on phosphor or scintillator types where their imaging performance has been improved through tweaking of various parameters (light guide structure, higher density, light emission spectrum matching to photodetectors, delayed fluorescence quenching etc) One key factor that largely determines the extrinsic efficiency of a specific phosphor is the particle size. Larger particles result in a higher luminance of the phosphor for the same radiation dose as does as a thicker phosphor layer (to a limit). There exists already a battery of models describing various phosphor qualities. However, particle size and thickness have not been treated as a fully independent variables in previous model works. Indirectly, the influence of these parameters is accounted for, but the existing models were either considered too general, containing several complex parameters and factors to cover all kind of cases or too highly specialised to be easily applicable to fluorescent detectors in diagnostic radiology. The aim of this thesis is therefore to describe and assess a simple model denoted the “LAC-model” (after the original authors Lindström and Alm Carlsson), developed for a fluorescent layer using individual sub-layers defined by the particle size diameter. The model is thought to be a tool for quickly evaluating various particle size and fluorescent layer thickness combinations for a chosen phosphor and design. It may also serve as a more intuitive description of the underlying parameters influencing the final extrinsic efficiency. Further tests affirmed the validity of the model through measurements. The LACmodel produced results deviating a maximum of +5 % from luminescence measurements. During the development of the model various assumptions and simplifications were made. One assumption was the absence of a so called “dead layer”. This is a layer supposedly surrounding each particle decreasing the efficiency of converting x-rays to light. It is not completely “dead” as in inactive but is thought to have a reduced efficiency. This phenomenon was struggled with, when historically designing electron beam stimulated phosphors for various applications (i.e. displays, TV tubes etc). There are also articles reporting dead layer influence for x-ray detectors (usually spectrometers i.e. not for imaging). By introducing a dead layer in the LAC-model the effect of the layer was investigated and was found to result in a change of less than 8% for the extrinsic efficiency. It was also noted that sometimes a dead layer effect may emerge at surfaces of a scintillator slab but not necessarily connected to the phosphor particles themselves. Due to differences between phosphor material and the surroundings, an interface effect arose to compete with the process of inherent dead layers of the individual particles. It was found to be mostly negligible for x-rays in the studied energy and material range. However, an effect was shown for electrons as incident ionising radiation which could shed some light on the strangely neglected apparent dead layer created this way. Finally, applications, one involving developing a prototype for checking the light field radiation field coincidence, were evaluated for overall performance and the optimisation level of the applied fluorescent layer. Interesting findings were made during the development process: for the first time to the knowledge of the author, focus shift wandering was quantified in the corresponding movement of the x-ray field edge and a non-trivial discussion on the concept of an apparent light field edge resulted in a modified definition of the same.
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| 14. |
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| 15. |
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| 16. |
- Wijk, Helle, 1958, et al.
(author)
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Verksamhetsförlagd utbildning på avancerad nivå : ny utmaning för specialistutbildningar för sjuksköterskor
- 2009
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In: Vård i Norden. - København : Sjuksköterskornas samarbete i Norden. - 0107-4083 .- 1890-4238. ; 29:94, s. 41-43
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Journal article (other academic/artistic)abstract
- The aim of this article is to discuss challenges in the development of Specialist Nursing Educations as a result of the 2007 Swedish Higher EducationReform: the implementation of the so-called Bologna process. Certain challenges follow this reform, particularly since the specialist nursingprogrammes will be part of the second cycle of the higher education system, and it will be possible to combine the professional degree witha masters degree (one year). Possible strategies in four areas related to the Specialist Nursing Education are discussed: integration of researchbasedknowledge, experienced-based knowledge, improvement knowledge, and strategies for collaboration between university institutions andclinics. Specific didactical issues are raised.
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| 17. |
- Öhlén, Joakim, 1958, et al.
(author)
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Students’ learning as the focus for shared involvement between universities and clinical practice : a didactic model for postgraduate degree projects
- 2012
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In: Advances in Health Sciences Education. - Dordrecht : Springer Netherlands. - 1382-4996 .- 1573-1677. ; 17:4, s. 471-487
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Journal article (peer-reviewed)abstract
- In an academic programme, completion of a postgraduate degree project could be a significant means of promoting student learning in evidence- and experience-based practice. In specialist nursing education, which through the European Bologna process would be raised to the master’s level, there is no tradition of including a postgraduate degree project. The aim was to develop a didactic model for specialist nursing students’ postgraduate degree projects within the second cycle of higher education (master’s level) and with a specific focus on nurturing shared involvement between universities and healthcare settings. This study embodies a participatory action research and theory-generating design founded on empirically practical try-outs. The 3-year project included five Swedish universities and related healthcare settings. A series of activities was performed and a number of data sources secured. Constant comparative analysis was applied. A didactic model is proposed for postgraduate degree projects in specialist nursing education aimed at nurturing shared involvement between universities and healthcare settings. The focus of the model is student learning in order to prepare the students for participation as specialist nurses in clinical knowledge development. The model is developed for the specialist nursing education, but it is general and could be applicable to various education programmes. © 2011 Springer Science+Business Media B.V.
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