| 1. |
- Eriksson, Frida, 1986, et al.
(författare)
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Impact of fast ions on density peaking in JET : fluid and gyrokinetic modeling
- 2019
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Ingår i: Plasma Physics and Controlled Fusion. - : Institute of Physics Publishing (IOPP). - 0741-3335 .- 1361-6587. ; 61:7
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Tidskriftsartikel (refereegranskat)abstract
- The effect of fast ions on turbulent particle transport, driven by ion temperature gradient (ITG)/trapped electron mode turbulence, is studied. Two neutral beam injection (NBI) heated JET discharges in different regimes are analyzed at the radial position rho(t) = 0.6, one of them an L-mode and the other one an H-mode discharge. Results obtained from the computationally efficient fluid model EDWM and the gyro-fluid model TGLF are compared to linear and nonlinear gyrokinetic GENE simulations as well as the experimentally obtained density peaking. In these models, the fast ions are treated as a dynamic species with a Maxwellian background distribution. The dependence of the zero particle flux density gradient (peaking factor) on fast ion density, temperature and corresponding gradients, is investigated. The simulations show that the inclusion of a fast ion species has a stabilizing influence on the ITG mode and reduces the peaking of the main ion and electron density profiles in the absence of sources. The models mostly reproduce the experimentally obtained density peaking for the L-mode discharge whereas the H-mode density peaking is significantly underpredicted, indicating the importance of the NBI particle source for the H-mode density profile.
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| 2. |
- Andersson, Andreas, 1980-
(författare)
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Utmattningsanalys av järnvägsbroar : En fallstudie av stålbroarna mellan Stockholm Central och Söder Mälarstrand, baserat på teoretiska analyser och töjningsmätningar
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Föreliggande avhandling omfattar en fallstudie av utmattningsrisken för järnvägsbroarna mellan Stockholm Central och Söder Mälarstrand. Ett stort antal utmattningssprickor i broarna över Söderström och Söder Mälarstrand har sedan länge varit kända. I samband med en bärighetsutredning av sträckan har ett stort antal anslutningspunkter i samtliga broar identifierats som kritiska avseende utmattningsrisk. Sträckan är den mest trafikerade i Sverige och de förenklade beräkningsmetoder som anges i Banverkets föreskrift för bärighetsberäkningar är i vissa fall inte tillämpliga. De formella bärighetsberäkningarna har visat på flerfaldiga överskridanden i utnyttjandegrad gällande utmattning. I de punkter som beräkningarna visar störst risk för utmattning har inga sprickor påträffats, trots omfattande förbandsbesiktningar. Beräkningarna baseras på typiserade spänningskollektiv och givet antal spänningsväxlingar, oberoende av den aktuella trafikmängden. Enligt bärighetsnormen ges möjlighet att beakta den verkliga trafikmängden baserat på historiskt bruttotonnage och typiserade trafiklaster. Dessa beräkningar har utförts och visar på ännu större risk för utmattning, jämfört med den förenklade metoden. I syfte att på ett ännu mer nyanserat sätt uppskatta utmattningsrisken har en metod använts, baserat på uppskattning av den faktiska trafikmängden och dess fördelningar. Beräkningarna baseras på trafikdata tillgänglig från Banverket. Metoden är tillämplig på andra järnvägsbroar på andra sträckor. Utöver teoretiska beräkningar har töjningsmätningar utförts. Under 2006 utförde dåvarande Carl Bro AB töjningsmätningar på bro över Söder Mälarstrand och viadukt söder om Söder Mälarstrand, avseende några enskilda tågöverfarter. Under 2008 utförde KTH Brobyggnad omfattande töjningsmätningar på bro över Söderström, avseende all trafik under en månads tid.
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| 3. |
- Axelsson Rosén, Stina, et al.
(författare)
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In vitro effects of antipsychotics on human platelet adhesion and aggregation and plasma coagulation
- 2007
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Ingår i: Clinical and experimental pharmacology & physiology. - : Wiley. - 0305-1870 .- 1440-1681. ; 34:8, s. 775-780
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Tidskriftsartikel (refereegranskat)abstract
- 1. Several studies suggest an association between venous thromboembolism and the use of antipsychotic drugs, especially clozapine, but the biological mechanisms are unknown. It has been suggested that antipsychotic drugs enhance aggregation of platelets and thereby increase the risk of venous thrombosis. The purpose of the present study was to examine the effects of clozapine and its main metabolite, N-desmethyl clozapine, as well as olanzapine, risperidone and haloperidol, on platelet adhesion and aggregation and on plasma coagulation in vitro. 2. Blood was collected from healthy subjects free of medication. Platelet adhesion to different protein surfaces and aggregation were measured in microplates. The coagulation methods of activated partial thromboplastin time (APTT) and prothrombin time were performed in platelet-poor plasma. 3. Clozapine was the only compound that increased platelet adhesion and aggregation and shortened APTT. The effect appeared at therapeutic concentrations and was significant but weak. 4. This weak effect of clozapine on haemostasis may explain, in part, the association of this compound and venous thromboembolism. © 2007 The Authors.
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| 5. |
- Eriksson, Andreas, 1973, et al.
(författare)
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A Case Study of Critical Reasons Behind Hospital Nurses Turnover Due to Challenges Across System Levels
- 2022
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Ingår i: Journal of Multidisciplinary Healthcare. - 1178-2390. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Purpose The aim of this study was to analyze how critical factors at different levels in a health-care system interact and impact nurses’ intention to leave and decision to quit their job at a hospital unit. Methods A case study of assistant and registered nurses’ intentions to leave as well as staff turnover at a smaller Swedish public hospital was performed. Employee surveys and interviews with assistant and registered nurses who had quit their job at four units in the hospital during the period 2012–2019 were performed. Critical factors regarding nurses’ intention to leave and staff turnover are analyzed by combining narrative methods with a critical incidence technique. Results Three main themes emerge from the analysis of factors contributing to the decision to quit, namely lack or loss of buffering factors, not owning your spare time and not feeling valued by and listened to by upper management. Conclusion Decision-makers, including hospital management, need to consider how supportive factors in nurses’ closest work environment that promote staff retention may be impacted by decisions at higher levels, such as health-care reorganizations and stricter governance. In this context, upper management adopting a servant leadership approach might contribute to employees to a greater extent feeling valued and being listened to. Finally, the results indicate that individual nurses’ recovery, ability to work and ability to coordinate their personal life with their work life need to be supported by policies and decisions at higher levels in order to retain nurses in intensive and emergency health-care settings.
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| 8. |
- Eriksson, Andreas, 1980-
(författare)
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Platelet Adhesion to Proteins in Microplates : Applications in Experimental and Clinical Research
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Platelets are crucial for prevention of blood loss after vessel injury. Platelet adhesion to disrupted vessel walls is mediated by receptors such as the GPIb-IX-V complex that binds von Willebrand factor and the collagen-binding integrin α2β1. Also cross-linking of platelets, mediated by αIIbβ3 that binds to fibrinogen, results in platelet aggregation that further contributes to hemostasis. Platelets are also important pathophysiologically because of their role in thrombus formation following atherosclerotic plaque rupture. Pharmacological treatments aimed to prevent such events include use of platelet inhibitors such as acetylsalicylic acid (ASA) and clopidogrel. Despite the presence of several different platelet function assays, no one has so far been considered useful for clinical evaluation of the effect of anti-platelet treatment. The aim of this thesis was to evaluate possible applications in experimental as well as in clinical research for a platelet adhesion assay performed during static conditions. In principle, platelets in plasma are allowed to attach to protein coated microplates. Adhered platelets are then detected by induction of an enzymatic reaction followed by spectrophotometric measurements of the developed product. Our results show that the platelet adhesion assay is able to detect experimentally induced activation as well as inhibition of platelets. The assay also seems useful for investigation of synergistically induced platelet activation, especially when the coated surface consists of albumin. This is exemplified by the combination of lysophosphatidic acid and adrenaline, which induced a synergistically increased platelet adhesion to albumin that was dependent on αIIbβ3-receptors and on the secretion of ADP. Furthermore, secretion of ADP as well as TXA2 seems to contribute to several adhesive reactions investigated with this assay. The dependence on secretion, together with results showing that adhesion to collagen and fibrinogen is dependent on α2β1- and αIIbβ3-receptors respectively, indicate that the adhesive interactions occurring in the assay is in accordance with the general knowledge about platelet function. Regarding clinical applications, we found that platelet adhesion was increased for patients with essential thrombocythemia (ET) compared to controls. This is in line with the in vivo function of ET-platelets since a common complication for ET-patients is thrombosis. Furthermore, the assay was able to detect effects of treatment with clopidogrel in patients with unstable angina. To some extent it also measured the effects of ASA-treatment. In conclusion, our results suggest that the assay is suitable for experimental research and that further studies should be performed aimed at developing the assay into a clinically useful device.
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| 9. |
- Eriksson, Andreas, 1980-, et al.
(författare)
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Platelets and Epinephrine
- 2008. - 1
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Ingår i: Research Progress on Epinephrine. - Hauppauge, NY, USA : Nova Science Publishers Inc.. - 9781604564433 ; , s. 73-94
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This new book is devoted to new research on epinephrine (INN) sometimes spelled "epinephrin" or "adrenalin" respectively, which is a hormone when carried in the blood and a neurotransmitter when it is released across a neuronal synapse. It is a catecholamine, a sympathomimetic monoamine derived from the amino acids phenylalanine and tyrosine.When secreted into the bloodstream, it rapidly prepares the body for action in emergency situations. The hormone boosts the supply of oxygen and glucose to the brain and muscles, while suppressing other non-emergency bodily processes (digestion in particular). It increases heart rate and stroke volume, dilates the pupils, and constricts arterioles in the skin and gut while dilating arterioles in skeletal muscles. It elevates the blood sugar level by increasing catalysis of glycogen to glucose in the liver, and at the same time begins the breakdown of lipids in fat cells. Like some other stress hormones, epinephrine has a suppressive effect on the immune system. Although epinephrine does not have any psychoactive effects, stress or arousal also releases norepinephrine in the brain. Norepinephrine has similar actions in the body, but is also psychoactive. Epinephrine is used as a drug to treat cardiac arrest and other cardiac dysrhythmias resulting in diminished or absent cardiac output; its action is to increase peripheral resistance via á±adrenoceptor vasoconstriction, so that blood is shunted to the body's core, and the â±adrenoceptor response which is increased cardiac rate and output (the speed and pronouncement of heart beats). This beneficial action comes with a significant negative consequence?increased cardiac irritability?which may lead to additional complications immediately following an otherwise successful resuscitation. Alternatives to this treatment include vasopressin, a powerful antidiuretic which also increases peripheral vascular resistance leading to blood shunting via vasoconstriction, but without the attendant increase in myocardial irritability.
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| 10. |
- Eriksson, Andreas, 1973, et al.
(författare)
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PROFiLE (Professional Literacy in English): a longitudinal study of the relationship between English as the medium of instruction and the development of professional English literacy
- 2015
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Ingår i: Integrating Content and Language in Higher Education (ICLHE 2015), 2-4 September, Université Libre de Bruxelles, Brussels, Belgium.
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Konferensbidrag (refereegranskat)abstract
- In many European universities, English is today used as a medium of instruction. One of the reasons is that it is believed that using English as a medium of instruction (EMI) can develop students’ subject-specific knowledge of English. This knowledge is seen as an asset in the workplace and often presented as providing a competitive advantage supporting professional success. The design of many educational programmes shows that this knowledge is supposed to develop incidentally rather than through explicit instruction. Recent research has, however, offered reason to question the extent to which such incidental learning actually occurs (Pecorari et al., 2011, Shaw et al. 2010). In addition, little is known about what type of knowledge is developed in different educational contexts. The present paper reports on the preliminary findings of a project testing assumptions about the development of English-language skills in the EMI environment.This longitudinal study is following students from several master's programmes from the beginning of their degrees into the workplace, gathering a range of data including language test results, interviews and observations. The aim is to carry out a thorough analysis of proficiency levels, the development of English literacy, and the extent to which activities in the programs support the development of disciplinary discourse and workplace demands. The findings will be used to discuss and recommend measures for improved practice.Preliminary analysis of the data reveals several themes: evidence that teaching staff and students see use of English as opposed to the local language as both opportunity and disadvantage; a wide diversity of English proficiency levels in the English-medium classroom (as shown by results from four tests distributed to approximately 150 students); and significant differences across participating programmes in terms of the sorts of English-language proficiencies their students are believed to need in the workplace.
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