| 1. |
- Abrahamsson, Christina, et al.
(author)
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DeltaT50 - a new method to assess temporal ventricular repolarization variability
- 2011
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In: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 44:4
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Journal article (peer-reviewed)abstract
- Background Increased beat-to-beat variability in cardiac repolarization time is a tentative risk marker of drug-induced torsades de pointes. We developed a new, automatic method based on the temporal variability of the T-wave down slope to assess this variability. Method and Results Leads V1 to V6 of resting electrocardiograms were recorded in 42 healthy subjects (18-68 years, 22 men). The temporal variability at 50% of the T-wave down slope, deltaT50 (1.5 ± 0.41 milliseconds; range, 0.86-2.66 milliseconds), was measured with an accuracy of 1 millisecond on at least 9 pairs of electrocardiogram complexes with a signal-to-noise ratio more than 10 and changes in the R-R interval less than 150 milliseconds. The correlation between repeated measurements of deltaT50 was high. DeltaT50 was measured without corrections for age, sex, heart rate, T-wave amplitude, signal-to-noise ratio, R-R variability, and QTcF because none of these factors explained more than 4% of the within-subject deltaT50 variability. Conclusion The beat-to-beat repolarization variability was measured with high fidelity with the deltaT50 method and was a robust measure in healthy volunteers.
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| 2. |
- Anter, Karin Fridell, et al.
(author)
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SYN-TES INTERDISCIPLINARY RESEARCH ON COLOUR AND LIGHT
- 2012
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In: Proceedings for Interim Meeting of the International Colour Association (AIC); AIC 2012 “In Color We Live: Color and Environment”, 22 – 25 September 2012, Taipei, Taiwan. - : The International Colour Association. ; , s. 80-83, s. 80-83
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Conference paper (peer-reviewed)abstract
- Colour and light have largely been considered as belonging to two different fields of knowledge, having disparate theoretical, terminological and methodological traditions. This creates a ground for misunderstandings and obstructs a fruitful interdisciplinary and interprofessional collaboration. A survey over international research literature from 2006 -2011 shows that there has been only little research on the spatial interaction between colour and light, but that the interest for this area has recently increased. The interdisciplinary Nordic research project SYN-TES: Human colour and light synthesis. Towards a coherent field of knowledge was carried out during 2010-11. Colour and light experts from Nordic universities and companies investigated different aspects of the spatial interaction between colour and light and its importance for human beings. This paper deals with the general learnings from the process. Specific results are presented in other papers at this conference.
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| 3. |
- Aster, Alexander, et al.
(author)
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Metal vs. ligand protonation and the alleged proton-shuttling role of the azadithiolate ligand in catalytic H-2 formation with FeFe hydrogenase model complexes
- 2019
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In: Chemical Science. - : Royal Society of Chemistry. - 2041-6520 .- 2041-6539. ; 10:21, s. 5582-5588
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Journal article (peer-reviewed)abstract
- Electron and proton transfer reactions of diiron complexes [Fe(2)adt(CO)(6)] (1) and [Fe(2)adt(CO)(4)(PMe3)(2)] (4), with the biomimetic azadithiolate (adt) bridging ligand, have been investigated by real-time IR- and UV-vis-spectroscopic observation to elucidate the role of the adt-N as a potential proton shuttle in catalytic H-2 formation. Protonation of the one-electron reduced complex, 1(-), occurs on the adt-N yielding 1H and the same species is obtained by one-electron reduction of 1H(+). The preference for ligand vs. metal protonation in the Fe-2(i,0) state is presumably kinetic but no evidence for tautomerization of 1H to the hydride 1Hy was observed. This shows that the adt ligand does not work as a proton relay in the formation of hydride intermediates in the reduced catalyst. A hydride intermediate 1HHy(+) is formed only by protonation of 1H with stronger acid. Adt protonation results in reduction of the catalyst at much less negative potential, but subsequent protonation of the metal centers is not slowed down, as would be expected according to the decrease in basicity. Thus, the adtH(+) complex retains a high turnover frequency at the lowered overpotential. Instead of proton shuttling, we propose that this gain in catalytic performance compared to the propyldithiolate analogue might be rationalized in terms of lower reorganization energy for hydride formation with bulk acid upon adt protonation.
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| 4. |
- Aunes-Jansson, Maria, et al.
(author)
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Decrease of the atrial fibrillatory rate, increased organization of the atrial rhythm and termination of atrial fibrillation by AZD7009
- 2013
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In: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 46:1, s. 29-35
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Journal article (peer-reviewed)abstract
- Background: The atrial fibrillatory rate (APR), on AZD7009 as compared to placebo, was investigated as a potential biomarker for electrophysiological effect in early antiarrhythmic drug development. Methods: Patients with permanent AF received infusions of AZD7009 and placebo in an exploratory two-way, single-blind, randomized cross-over study. The ECG was continuously recorded, and following QRST cancellation the APR, its standard deviation (SD), the exponential decay and the atrial electrogram amplitude were determined as 3-min averages. Results: The mean APR rapidly decreased by 43% from baseline (394 +/- 38 to 225 +/- 61 fibrillations/min, p = 0.0003) on AZD7009, but not on placebo. The SD of the AFR and the exponential decay decreased in parallel. In 2 of 8 patients, termination of AF occurred after the APR had decreased by 58% and 53%, respectively. Conclusions: The APR may potentially serve as a biomarker of electrophysiological effects in early evaluation of rhythm control agents. (C) 2013 Elsevier Inc. All rights reserved.
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| 5. |
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| 6. |
- Berggren, Gustav, 1980-
(author)
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Mimicking Nature – Synthesis and Characterisation of Manganese Complexes of Relevance to Artificial Photosynthesis
- 2009
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Doctoral thesis (other academic/artistic)abstract
- The development of efficient catalyst for water oxidation is of paramount importance to artificial photosynthesis, but before this can be achieved a deeper understanding of this reaction is essential. In nature this reaction occurs in a tetranuclear Mn-cluster which serves as the work-horse of oxygenic photosynthesis. This thesis summarises my efforts at developing molecular systems capable of mimicking this complex employing a biomimetic approach. Three different approaches towards this goal are described here-in. The first section describes a screening study, in which a number of manganese complexes were tested to see whether or not they were capable of catalysing the formation of dioxygen when treated with different oxidants (Papers I). For those reactions in which dioxygen formation was observed the reactions were repeated in labelled water and the incorporation of labelled O-atoms was studied by mass spectrometry. This allowed us to determine to what extent water was the source of the evolved dioxygen (Papers II-III). In Chapter three a reported catalyst and a derivative thereof is studied in depth. The influence of changes to the ligand on the oxygen–oxygen bond forming reaction could unfortunately not be reliably addressed, because of the instability of the complexes under “catalytic” conditions. Nevertheless, the study allowed us to revise the “carboxylate shift”-mechanism suggested in the literature (Papers IV-V). Chapter four describes the continuation of my work on ligands featuring the carboxylate ligand motif first introduced in Chapter three. In this study ligands containing multiple binding pockets were designed and synthesised (Paper VI). A better understanding of the mechanism in the natural water oxidising enzyme will facilitate the design of biomimetic complexes, this is discussed in Chapter five. In this work model complexes (Paper VII) are used to study the mechanism by which natures own water oxidising catalyst performs this reaction.
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| 7. |
- Berggren, Johan, et al.
(author)
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GASTRIC BYPASS SURGERY HAS GREATER EFFECT THAN CALORIE RESTRICTION ON INCRETIN RELEASE AND INSULIN SECRETION ALREADY ON POSTOP. DAY 1
- 2015
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In: Obesity Surgery. - 1708-0428. ; 25:Suppl 1, s. 85-85
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Conference paper (other academic/artistic)abstract
- Background: Gastric bypass surgery (GBP) provokes rapid improvement of type 2 diabetes (T2D) prior to significant weight loss. Thishas been attributed to altered secretion of the two incretin hormones glucagon-like peptide 1 (GLP-1) and glucose-dependentinsulinotropic polypeptide (GIP). Here we studied the effects of very low calorie diet (VLCD) vs. the immediate effects of GBP onglycaemia and incretin release.Methods: Eight T2D obese women and 8 obese controls (C) underwent mixed meal tests (MMT) 4 w before (MMT-4w), 1 day before(MMT-1d), 1 day after (MMT+1d) and six weeks after (MMT+6w) gastric bypass. MMT-4w was performed before VLCD and MMT+1dconstituted the first postoperative meal. Glucose, insulin and incretins were analyzed. Gastric bypass surgery was standardized to a 50cm biliary limb and 150 cm alimentary limb and a 5 cm gastric pouch.OBES SURG (2015) 25 (Suppl 1):S1–S364 S85Results: Despite similar glucose levels, the insulin response was markedly increased at MMT+1d, compared to MMT-4w and MMT-1d(2.4- and 2.8-fold). At MMT+6w a more rapid rise was evident. GLP-1 levels were similar in all MMTs except MMT+6w where anincreased response was seen; this was stronger in T2D vs. C. The GIP-response was higher at MMT+1d, compared to MMT-4w andMMT-1d (1.6- and 1.4-fold). The increased GIP-response was attenuated in C at MMT+6w, but still evident in T2D.Conclusions: VLCD has minor impact on the parameters analyzed; rather GBP per se elicits an immediate stimulatory effect on insulinand GIP levels in response to an MMT as first meal on day 1 after surgery.
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| 8. |
- BERGGREN, JOHAN, et al.
(author)
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Roux-en-Y gastric bypass versus calorie restriction: support for surgery as the direct contributor to aloncltered responses of insulin and incretins to a mixed meal
- 2017
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In: Surgery for Obesity and Related Diseases. - : Elsevier BV. - 1550-7289. ; 13:2, s. 234-242
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Journal article (peer-reviewed)abstract
- AbstractObjectiveTo study the immediate effects of Roux-en-Y gastric bypass (RYGB) on glucose homeostasis, insulin, and incretin responses to mixed-meal tests compared with the effects of calorie restriction (CR).SettingUniversity-affiliated bariatric surgery clinic.BackgroundRYGB induces remission of type 2 diabetes (T2 D) long before significant weight loss occurs. The time course and underlying mechanisms of this remission remain enigmatic. A prevailing theory is that secretory patterns of incretin hormones are altered due to rearrangement of the gastrointestinal tract. To what extent reduced calorie intake contributes to the remission of T2 D is unknown.MethodsNine normoglycemic patients and 10 T2 D patients were subjected to mixed-meal tests (MMT) 4 weeks before surgery before initiation of a very low calorie diet regimen (MMT-4 w), 1 day before surgery on a very low calorie diet regimen (MMT-1 d), on the morning of the first day after surgery (MMT+1 d; first postsurgical meal), and 6 weeks after surgery (MMT+6 w). Insulin, glucose, active glucagon-like peptide 1 (GLP-1), and glucose-dependent insulinotropic polypeptide (GIP) were measured.ResultsCR lowered insulin in T2 D patients, whereas glucose, GIP, and GLP-1 were unaffected. RYGB immediately increased plasma insulin and GIP. The GLP-1 response was delayed compared with the GIP response. T2 D patients exhibited lower insulin responses after RYGB compared with normoglycemic patients. GIP responses were similar in both groups at all occasions, whereas T2 D patients displayed markedly elevated GLP-1 responses 6 weeks after RYGB. Glucose was unaffected by CR and RYGB in both groups. Insulin sensitivity was unaffected by CR but improved with RYGB.ConclusionRYGB exerts powerful and immediate effects on insulin and incretin responses to food, independently of changes caused by CR.
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| 9. |
- Berggren, Peter, et al.
(author)
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Coping with large disruptions in the payment system : stakeholder experience from stakeholder workshops and computer based simulation gaming exercises
- 2020
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In: Proceedings of the 2020 the 3rd International Conference on Computers in Management and Business (ICCMB 2020) Session - Computer and Mobile Technology. - New York : Association for Computing Machinery (ACM). - 9781450376778 ; , s. 141-145, s. 141-145
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Conference paper (peer-reviewed)abstract
- In this paper, we describe a work in progress where a mixed methods approach is used to increase insight into what kind of consequences a temporal disruption or total breakdown of the payment system creates for a large variety of societal actors and to increase insight in how their collaborative behaviour can be guided to be more resilient. This approach includes data from different types of data collections; workshop with high-level decisionmakers from involved sectors, interviews with citizens, representatives from the fuel, foods, and finance sectors, as well as experiences from 15 simulation game exercises with stakeholders. The triangulated and aggregated outcomes of the different data collections resulted in a set of recommendations on how to cope with disruptions in the card payment system.
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| 10. |
- Bergsten, Linnea, et al.
(author)
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Designing engaging computer based simulation games for increasing societal resilience to payment system
- 2020
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In: Proceedings of the 2020 the 3rd International Conference on Computers in Management and Business (ICCMB 2020) Session - Computer and Mobile Technology. - New York : Association for Computing Machinery (ACM). - 9781450376778 ; , s. 166-172, s. 166-172
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Conference paper (peer-reviewed)abstract
- Large or lengthy disruptions to the card payment system are threats that can cause crisis in society, especially in countries where other payment options are scarce. This paper presents a study that provides suggestions on how to improve a simulation game used to increase societal resilience to payment system disruptions. Questionnaires and interviews have been used to investigate how 16 participant in crisis exercises experience realism, relevance and validity in such exercises. Suggestions on how to improve the simulation game are provided, such as improvements to the graphical interface and introducing supporting roles from the exercise management.
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