1. |
- Bengtsson, Dennis, 1995-, et al.
(författare)
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The effects of interpersonal development programmes with sport coaches and parents on youth athlete outcomes : a systematic review and meta-analysis
- 2024
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Ingår i: Psychology of Sport And Exercise. - Amsterdam : Elsevier. - 1469-0292 .- 1878-5476. ; 70
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Forskningsöversikt (refereegranskat)abstract
- Interpersonal coach-and parent development programmes (CDP and PDP, respectively), have the goal to foster positive youth sport experiences through high-quality relations between coaches, parents, and youth athletes. In this paper we systematically reviewed the extant literature and estimate the overall magnitude of such programmes and how they can inform future interventions. Specifically, we aimed to: (a) conduct a systematic review on the literature of interpersonal CDPs and PDPs within the youth sport context; (b) examine the effects of such interventions on youth athlete outcomes via a meta-analysis. English written peer-reviewed publications and grey literature was identified through electronic search in databases and manual searches of reference lists. By utilising a priori criteria for inclusion and exclusion, 33 studies describing interpersonal CDPs, and PDPs were identified in the systematic review. Studies that presented required data for estimation of Hedge's g effect sizes were included in the meta-analysis (k = 27). By and large, the included studies used a quasi-experimental design (58%), sampled from team sports (79%), and reported several delivery methods (e.g., workshops, audio feedback, observations, peer group discussions) and outcome measures (e.g., anxiety, autonomous motivation, self-confidence). Some interventions were based on the same delivery protocols (e.g., Coach Effectiveness Training, Mastery Approach to Coaching) or theoretical frameworks (e.g., Achievement Goal Theory, Self-Determination Theory). The meta-analysis showed statistically significant small, and medium, effect sizes on a subsample of youth athlete outcomes (e.g., task-related climate, fun and enjoyment, anxiety), indicating that coach interpersonal skills can contribute to positive youth sport experiences. Theory-based interpersonal CDPs and PDPs are recommended to expand the knowledge in this field of research.
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2. |
- Bengtsson, Dennis, 1995-, et al.
(författare)
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The effects of interpersonal development programmes with sport coaches and parents on youth athlete outcomes : A systematic review and meta-analysis
- 2024
-
Ingår i: Psychology of Sport And Exercise. - Amsterdam : Elsevier. - 1469-0292 .- 1878-5476. ; 70
-
Forskningsöversikt (refereegranskat)abstract
- Interpersonal coach-and parent development programmes (CDP and PDP, respectively), have the goal to foster positive youth sport experiences through high-quality relations between coaches, parents, and youth athletes. In this paper we systematically reviewed the extant literature and estimate the overall magnitude of such programmes and how they can inform future interventions. Specifically, we aimed to: (a) conduct a systematic review on the literature of interpersonal CDPs and PDPs within the youth sport context; (b) examine the effects of such interventions on youth athlete outcomes via a meta-analysis. English written peer-reviewed publications and grey literature was identified through electronic search in databases and manual searches of reference lists. By utilising a priori criteria for inclusion and exclusion, 33 studies describing interpersonal CDPs, and PDPs were identified in the systematic review. Studies that presented required data for estimation of Hedge's g effect sizes were included in the meta-analysis (k = 27). By and large, the included studies used a quasi-experimental design (58%), sampled from team sports (79%), and reported several delivery methods (e.g., workshops, audio feedback, observations, peer group discussions) and outcome measures (e.g., anxiety, autonomous motivation, self-confidence). Some interventions were based on the same delivery protocols (e.g., Coach Effectiveness Training, Mastery Approach to Coaching) or theoretical frameworks (e.g., Achievement Goal Theory, Self-Determination Theory). The meta-analysis showed statistically significant small, and medium, effect sizes on a subsample of youth athlete outcomes (e.g., task-related climate, fun and enjoyment, anxiety), indicating that coach interpersonal skills can contribute to positive youth sport experiences. Theory-based interpersonal CDPs and PDPs are recommended to expand the knowledge in this field of research. © 2023 The Authors
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3. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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4. |
- Abdallah, J, et al.
(författare)
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Rapidity-alignment and p(T) compensation of particle pairs in hadronic Z(0) decays
- 2002
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 533:3-4, s. 243-252
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Tidskriftsartikel (refereegranskat)abstract
- Observation is made of rapidity-alignment of K+K- and (p) over barp pairs which results from their asymmetric orientation in rapidity, with respect to the direction from primary quark to antiquark. The K+K- and (p) over barp data are consistent with predictions from the fragmentation string model. However, the (p) over barp data strongly disagree with the conventional implementation of the cluster model. The non-perturbative process of 'gluon splitting to diquarks' has to be incorporated into the cluster model for it to agree with the data. Local conservation of PT between particles nearby in rapidity (i.e., p(T) compensation) is analysed with respect to the thrust direction for pi(+)pi(-), K+K-, and (p) over barp pairs. In this case, the string model provides fair agreement with the data. The cluster model is incompatible with the data for all three particle pairs. The model with its central premiss of isotropically-decaying clusters predicts a p(T) correlation not seen in the data. (C) 2002 Elsevier Science B.V. All rights reserved.
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5. |
- Abdallah, J, et al.
(författare)
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Search for charged Higgs bosons in e(+)e(-) collisions root s=189-202 GeV
- 2002
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 525:1-2, s. 17-28
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Tidskriftsartikel (refereegranskat)abstract
- A search for pair-produced charged Higgs bosons was performed in the high energy data collected by the DELPHI detector at LEP II at centre-of-mass energies from 189 GeV to 202 GeV. The three different final states, taunutaunu, c (s) over bar(c) over bars and c (s) over bar taunu were considered. New methods were applied to reject wrong hadronic jet pairings and for the tau identification, where a discriminator based on tau polarisation and polar angles was used. No excess of data compared to the expected Standard Model processes was observed and the existence of a charged Higgs boson with mass lower than 71.5 GeV/c(2) is excluded at the 95% confidence level. (C) 2002 Published by Elsevier Science B.V.
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6. |
- Abdallah, J, et al.
(författare)
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Searches for neutral Higgs bosons in e(+)e(-), collisions from root s=191.6 to 201.7 GeV
- 2002
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 23:3, s. 409-435
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Tidskriftsartikel (refereegranskat)abstract
- Neutral Higgs bosons of the Standard Model (SM) and the Minimal Supersymmetric Standard Model (MSSM) were searched for in the data collected in 1999 by the DELPHI experiment at centre-of-mass energies between 191.6 and 201.7 GeV with a total integrated luminosity of 228 pb(-1). These analyses, in combination with our results at lower energies, set 95% confidence level lower mass bounds on the Standard Model Higgs boson (107.3 GeV/c(2)) and on the lightest neutral scalar (85.9 GeV/c(2)) and neutral pseudoscalar (86.5 GeV/c(2)) Higgs bosons in representative scans of the MSSM parameter space. An extended scan of the MSSM parameter space was also performed to test the robustness of these limits.
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7. |
- Abreu, P, et al.
(författare)
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b-tagging in DELPHI at LEP
- 2004
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 32:2, s. 185-208
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Tidskriftsartikel (refereegranskat)abstract
- The standard method used for tagging b-hadrons in the DELPHI experiment at the CERN LEP Collider is discussed in detail. The main ingredient of b-tagging is the impact parameters of tracks, which relies mostly on the vertex detector. Additional information, such as the mass of particles associated to a secondary vertex, significantly improves the selection efficiency and the background suppression. The paper describes various discriminating variables used for the tagging and the procedure of their combination. In addition, applications of b-tagging to some physics analyses, which depend crucially on the performance and reliability of b-tagging, are described briefly.
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8. |
- Abreu, P., et al.
(författare)
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Measurement of the mass and width of the W boson in e+e- collisions at √s = 189 GeV
- 2001
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Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 511:2-4, s. 159-177
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Tidskriftsartikel (refereegranskat)abstract
- A measurement of the W mass and width has been performed by the DELPHI Collaboration using the data collected during 1998. The data sample has an integrated luminosity of 155 pb-1 and an average centre-of-mass energy of 188.6 GeV. Results are obtained by applying the method of direct reconstruction of the mass of the W from its decay products in both the W+W- → lvlqq′ and W+W- → qq′qq′ channels. The W mass result for the 1998 data set is MW = 80.387 ± 0.087(stat) ± 0.034(syst) ± 0.017(LEP) ± 0.035(FSI) GeV/c2, where FSI represents the uncertainty due to final state interaction effects in the qq′qq′ channel, and LEP represents that arising from the knowledge of the beam energy of the accelerator. Combining this result with those previously published by the DELPHI Collaboration gives the result MW = 80.359 ± 0.074(stat) ± 0.032(syst) ± 0.017(LEP) ± 0.033(FSI) GeV/c2. The combined value for the W width is λW = 2.266 ± 0.176(stat)± 0.056(syst)± 0.052(FSI) GeV/c2.
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9. |
- Bragadottir, Gudrun, et al.
(författare)
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Low-dose vasopressin increases glomerular filtration rate, but impairs renal oxygenation in post-cardiac surgery patients.
- 2009
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Ingår i: Acta Anaesthesiol Scand. - : Wiley. - 1399-6576. ; 53:8, s. 1052-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The beneficial effects of vasopressin on diuresis and creatinine clearance have been demonstrated when used as an additional/alternative therapy in catecholamine-dependent vasodilatory shock. A detailed analysis of the effects of vasopressin on renal perfusion, glomerular filtration, excretory function and oxygenation in man is, however, lacking. The objective of this pharmacodynamic study was to evaluate the effects of low to moderate doses of vasopressin on renal blood flow (RBF), glomerular filtration rate (GFR), renal oxygen consumption (RVO2) and renal oxygen extraction (RO2Ex) in post-cardiac surgery patients. METHODS: Twelve patients were studied during sedation and mechanical ventilation after cardiac surgery. Vasopressin was sequentially infused at 1.2, 2.4 and 4.8 U/h. At each infusion rate, systemic haemodynamics were evaluated by a pulmonary artery catheter, and RBF and GFR were measured by the renal vein thermodilution technique and by renal extraction of 51chromium-ethylenediaminetetraacetic acid, respectively. RVO2 and RO2Ex were calculated by arterial and renal vein blood samples. RESULTS: The mean arterial pressure was not affected by vasopressin while cardiac output and heart rate decreased. RBF decreased and GFR, filtration fraction, sodium reabsorption, RVO2, RO2Ex and renal vascular resistance increased dose-dependently with vasopressin. Vasopressin exerted direct antidiuretic and antinatriuretic effects. CONCLUSIONS: Short-term infusion of low to moderate, non-hypertensive doses of vasopressin induced a post-glomerular renal vasoconstriction with a decrease in RBF and an increase in GFR in post-cardiac surgery patients. This was accompanied by an increase in RVO2, as a consequence of the increases in the filtered tubular load of sodium. Finally, vasopressin impaired the renal oxygen demand/supply relationship.
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10. |
- Damén, Tor, et al.
(författare)
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Atrial natriuretic peptide does not degrade the endothelial glycocalyx: A secondary analysis of a randomized porcine model
- 2021
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Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 65:9, s. 1305-1312
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Tidskriftsartikel (refereegranskat)abstract
- Background: The atrial natriuretic peptide (ANP) released from the heart regulates intravascular volume and is suspected to increase capillary permeability. Contradictory results regarding ANP and glycocalyx degradation have been reported. The aim of this study was to investigate if an infusion of ANP causes degradation of the endothelial glycocalyx. Methods: Twenty pigs, pretreated with 250mg methylprednisolone, were randomized to receive an infusion of either ANP (50ng/kg/min) (n=10) or 0.9% NaCl (n=10) during 60min. Endothelial glycocalyx components (heparan sulphate proteoglycan and hyaluronic acid), Hct, calculated plasma volume and colloid osmotic pressure were measured from baseline to 60min. Results: There was no difference between the control and intervention groups for heparan sulphate proteoglycan and hyaluronic acid corrected for the change in plasma volume (P=.333 and 0.197). Hct increased with 1.8±2.2% in the intervention group (P=.029) with no change −0.5±2.3% in the control group (P=.504). The plasma volume decreased in the intervention group with −8.4±10% (P=.034) with no change in the control group 3.1±12% (P=.427). Median changes in colloid osmotic pressures in the control and intervention group were −0.39 [95% CI, −1.88-0.13] and 0.9 [95% CI, 0.00-1.58], respectively (P=.012). Conclusions: In this randomized porcine study, an ANP infusion did not cause endothelial glycocalyx degradation but decreased the plasma volume most probably due to precapillary vasodilation and increased filtration. © 2021 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd
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11. |
- Damén, Tor, et al.
(författare)
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Effects of different mean arterial pressure targets on plasma volume, ANP and glycocalyx-A randomized trial.
- 2021
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Ingår i: Acta anaesthesiologica Scandinavica. - : Wiley. - 1399-6576 .- 0001-5172. ; 65:2, s. 220-227
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Tidskriftsartikel (refereegranskat)abstract
- Arterial haematocrit (Hct) has been shown to decrease after anaesthesia induction, most probably because of an increased plasma volume (PV). The primary objective was to quantify change in PV if mean arterial pressure (MAP) was kept at baseline level or allowed to decrease to 60mm Hg. Our secondary objective was to evaluate underlying mechanisms of this response.Twenty-four coronary artery bypass patients were randomized to a higher (90mm Hg, intervention group) or lower (60mm Hg, control group) MAP by titration of norepinephrine. During the experimental procedure, no fluids were administered. Baseline PV was measured by 125 I-albumin and the change in PV was calculated from the change in Hct. Changes in MAP, plasma 125 I-albumin, colloid osmotic pressure, albumin, Mid Regional-pro Atrial Natriuretic Peptide (MR-proANP) and endothelial glycocalyx components were measured from baseline to 50minutes after anaesthesia induction.The MAP during the trial was 93±9mm Hg in the intervention group and 62±5mm Hg in the control group. PV increased with up to 420±180mL in the control group and 45±130mL in the intervention group (P<.001). Albumin and colloid osmotic pressure decreased significantly more in the control group. MR-proANP increased in the control group but no shedding of the glycocalyx layer was detected in either of the groups.Allowing mean arterial pressure to fall to 60mm Hg during anaesthesia induction, increases the plasma volume due to reabsorption of interstitial water, with no ANP-induced degradation of the endothelial glycocalyx.
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12. |
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13. |
- Daskalakis, Kosmas, et al.
(författare)
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Ex vivo activity of cytotoxic drugs and targeted agents in Small Intestinal NETs
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Small Intestinal Neuroendocrine Tumours (SI-NET) are considered to be generally resistant to systemic treatment. To date predictive markers for drug activity are lacking.Patients and Methods: Tumour samples from 27 patients with SI-NET were analyzed ex vivo for sensitivity to a panel of cytotoxic drugs and targeted agents using a short-term total cell kill assay. Samples of renal cancer, colorectal cancer (CRC), ovarian cancer, and chronic lymphocytic leukemia (CLL) were included for comparison. For the SI-NET subset, drug sensitivity was analyzed in relation to clinico-pathological variables and pre-treatment biomarkers.Results: For standard cytotoxic drugs, SI-NETs demonstrated similar or higher sensitivity to 5-FU, platinums, gemcitabine and doxorubicin compared with CRC. For targeted kinase inhibitors, SI-NET was among the most sensitive diagnoses. CLL and ovarian cancer were generally the most sensitive diagnoses to both cytotoxic drugs and protein kinase inhibitors. The mTOR inhibitor sirolimus exhibited modest cytotoxic activity.Individual SI-NET samples demonstrated great variability in ex vivo sensitivity for most drugs. Cross-resistance between different drugs also varied considerably, being higher among protein kinase inhibitors.Age, stage, grade, peritoneal carcinomatosis and extra-abdominal metastases as well as serum chromogranin A and urine 5-HIAA concentrations at diagnosis did not correlate to drug sensitivity ex vivo.Conclusions: SI-NETs exhibit variable but generally intermediate sensitivity ex vivo to cytotoxic and targeted drugs. Clinico-pathological factors and currently used biomarkers were not clearly associated to ex vivo sensitivity, challenging these criteria for treatment decisions in SI-NETs. The great variability in drug sensitivity calls for individualized selection of therapy.
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14. |
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15. |
- Daskalakis, Kosmas, et al.
(författare)
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Ex vivo activity of cytotoxic drugs and targeted agents in small intestinal neuroendocrine tumors
- 2018
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Ingår i: Endocrine-Related Cancer. - 1351-0088 .- 1479-6821. ; 25:4, s. 471-480
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Tidskriftsartikel (refereegranskat)abstract
- Small intestinal neuroendocrine tumors (SI-NETs) are generally considered resistant to systemic treatment. To date, predictive markers for drug activity are lacking. Tumor samples from 27 patients with SI-NETs were analyzed ex vivo for sensitivity to a panel of cytotoxic drugs and targeted agents using a short-term total cell kill assay. Samples of renal cancer, colorectal cancer (CRC), ovarian cancer and chronic lymphocytic leukemia (CLL) were included for comparison. For the SI-NET subset, drug sensitivity was analyzed in relation to clinicopathological variables and pre-treatment biomarkers. For cytotoxic drugs, SI-NETs demonstrated similar or higher sensitivity to 5-FU, platinum, gemcitabine and doxorubicin compared with CRC. For several of the targeted kinase inhibitors, SI-NET was among the most sensitive solid tumor types. CLL and ovarian cancer were generally the most sensitive tumor types to both cytotoxic drugs and protein kinase inhibitors. SI-NET was more sensitive to the mTOR inhibitor sirolimus than the other solid tumor types tested. Individual SI-NET samples demonstrated great variability in ex vivo sensitivity for most drugs. Cross-resistance between different drugs also varied considerably, being higher among protein kinase inhibitors. Age, stage, grade, peritoneal carcinomatosis and extra-abdominal metastases as well as serum chromogranin A and urine 5-HIAA concentrations at diagnosis did not correlate to drug sensitivity ex vivo. SI-NETs exhibit intermediate sensitivity ex vivo to cytotoxic and targeted drugs. Clinicopathological factors and currently used biomarkers are not clearly associated to ex vivo sensitivity, challenging these criteria for treatment decisions in SI-NET. The great variability in drug sensitivity calls for individualized selection of therapy.
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16. |
- Decker, Ralph, 1968, et al.
(författare)
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Different thresholds of tissue-specific dose-responses to growth hormone in short prepubertal children
- 2012
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Ingår i: BMC Endocrine Disorders. - : Springer Science and Business Media LLC. - 1472-6823. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Background In addition to stimulating linear growth in children, growth hormone (GH) influences metabolism and body composition. These effects should be considered when individualizing GH treatment as dose-dependent changes in metabolic markers have been reported. Hypothesis: There are different dose-dependent thresholds for metabolic effects in response to GH treatment. Method A randomized, prospective, multicentre trial TRN 98-0198-003 was performed for a 2-year catch-up growth period, with two treatment regimens (a) individualized GH dose including six different dose groups ranging from 17--100 mug/kg/day (n=87) and (b) fixed GH dose of 43 mug/kg/day (n=41). The individualized GH dose group was used for finding dose--response effects, where the effective GH dose (ED 50%) required to achieve 50% Delta effect was calculated with piecewise linear regressions. Results Different thresholds for the GH dose were found for the metabolic effects. The GH dose to achieve half of a given effect (ED 50%, with 90% confidence interval) was calculated as 33(+/-24.4) mug/kg/day for [increment] left ventricular diastolic diameter (cm), 39(+/-24.5) mug/kg/day for [increment] alkaline phosphatase (mukat/L), 47(+/-43.5) mug/kg/day for [increment] lean soft tissue (SDS), 48(+/-35.7) mug/kg/day for [increment] insulin (mU/L), 51(+/-47.6) mug/kg/day for [increment] height (SDS), and 57(+/-52.7) mug/kg/day for [increment] insulin-like growth factor I (IGF-I) SDS. Even though lipolysis was seen in all subjects, there was no dose--response effect for Delta fat mass (SDS) or Delta leptin ng/ml in the dose range studied. None of the metabolic effects presented here were related to the dose selection procedure in the trial. Conclusions Dose-dependent thresholds were observed for different GH effects, with cardiac tissue being the most responsive and level of IGF-I the least responsive. The level of insulin was more responsive than that of IGF-I, with the threshold effect for height in the interval between.
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17. |
- Jonsson, Andreas, 1974-, et al.
(författare)
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Engineering of a femtomolar affinity binding protein to human serum albumin
- 2008
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Ingår i: Protein Engineering Design & Selection. - : Oxford University Press (OUP). - 1741-0126 .- 1741-0134. ; 21:8, s. 515-527
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Tidskriftsartikel (refereegranskat)abstract
- We describe the development of a novel serum albumin binding protein showing an extremely high affinity (K(D)) for HSA in the femtomolar range. Using a naturally occurring 46-residue three-helix bundle albumin binding domain (ABD) of nanomolar affinity for HSA as template, 15 residues were targeted for a combinatorial protein engineering strategy to identify variants showing improved HSA affinities. Sequencing of 55 unique phage display-selected clones showed a strong bias for wild-type residues at nine positions, whereas various changes were observed at other positions, including charge shifts. Additionally, a few non-designed substitutions appeared. On the basis of the sequences of 12 variants showing high overall binding affinities and slow dissociation rate kinetics, a set of seven 'second generation' variants were constructed. One variant denoted ABD035 displaying wild-type-like secondary structure content and excellent thermal denaturation/renaturation properties showed an apparent affinity for HSA in the range of 50-500 fM, corresponding to several orders of magnitude improvement compared with the wild-type domain. The ABD035 variant also showed an improved affinity toward serum albumin from a number of other species, and a capture experiment involving human serum indicated that the selectivity for serum albumin had not been compromised from the affinity engineering.
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18. |
- Kaminski, Clemens, et al.
(författare)
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Development of high speed spectroscopic imaging techniques for the time resolved study of spark ignition phenomena
- 2000
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191.
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports on the development of novel time resolved spectroscopic imaging techniques for the study of spark ignition phenomena in combustion cells and an SI-engine. The techniques are based on planar laser induced fluorescence imaging (PLIF) of OH radicals, on fuel tracer PLIF, and on chemiluminescence. The techniques could be achieved at repetition rates reaching several hundreds of kilo-Hz and were cycle resolved. These techniques offer a new path along which engine related diagnostics can be undertaken, providing a wealth of information on turbulent spark ignition.
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19. |
- Kjellin, Andreas, 1974-
(författare)
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Visualizing Dynamics –The Perception of Spatiotemporal Data in 2D and 3D
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In many command and control situations the understanding of dynamic events is crucial. With today’s development of hard- and software architecture, we have the possibility to visualize data in two-dimensional (2D) and three-dimensional (3D) images. The aim of this thesis is therefore to investigate different approaches to visualizing dynamic events. The visualization techniques investigated include 2D animation and time representations as markings on a 2D map. In 3D the visualization technique investigated is the “space time-cube” A further aim is to study whether the Cue Probability Learning (CPL) paradigm can be used to evaluate visualizations. By mapping time onto a spatial dimension, in the 2D visualization as lines with different densities and in 3D as height over the map, a simultaneous visualization of space and time is possible. The findings are that this mapping of time onto space is beneficial to users as compared with animations, but the two mapping techniques are not interchangeable. If a task requires judgments of metric spatial properties, a 2D visualization is more beneficial; however, if the task only requires judgments of more qualitative aspects, a 3D visualization is more beneficial. When we look at a 3D visualization, we utilize different sources of depth information. These sources are always present and each defines either a 3D scene or a projection surface. By using these different sources of depth information wisely, a visualization can be created that efficiently shows relevant information to a user while requiring a minimal amount of specialized hardware. Finally, the CPL paradigm seems to be a worthwhile option as an experimental paradigm in visualization experiments. One of the advantages of CPL is that novice users can be trained to be task experts in a controlled and time-efficient way.
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20. |
- Kolsrud, Oscar, et al.
(författare)
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Effects of atrial natriuretic peptide on renal function during cardiopulmonary bypass: a randomized pig model.
- 2020
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Ingår i: European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery. - : Oxford University Press (OUP). - 1873-734X. ; 57:4, s. 652-659
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Tidskriftsartikel (refereegranskat)abstract
- Acute kidney injury is a well-known complication after cardiac surgery and cardiopulmonary bypass (CPB). In this experimental animal study, we evaluated the effects of atrial natriuretic peptide (ANP) on renal function, perfusion, oxygenation and tubular injury during CPB.Twenty pigs were blindly randomized to continuous infusion of either ANP (50ng/kg/min) or placebo before, during and after CPB. Renal blood flow as well as cortical and medullary perfusion was measured. Blood was repeatedly sampled from the renal vein. Glomerular filtration rate was measured by infusion clearance of 51Cr-EDTA.Glomerular filtration rate was higher (P<0.001), whereas renal blood flow or renal oxygen delivery was not affected by ANP during CPB. Renal oxygen consumption did not differ between groups during CPB, whereas renal oxygen extraction was higher in the ANP group (P=0.03). Urine flow and sodium excretion were higher in the ANP group during CPB. Blood flow in the renal medulla, but not in the cortex, dropped during CPB, an effect that was not seen in the animals that received ANP.ANP improved renal function during CPB. Despite impaired renal oxygenation, ANP did not cause tubular injury, suggesting a renoprotective effect of ANP during CPB. Also, CPB induced a selectively reduced blood flow in the renal medulla, an effect that was counteracted by ANP.
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21. |
- Lackmann, Tim, 1983, et al.
(författare)
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Investigation of turbulence–chemistry interactions in a heavy-duty diesel engine with a representative interactive linear eddy model
- 2020
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Ingår i: International Journal of Engine Research. - : SAGE Publications. - 1468-0874 .- 2041-3149. ; 21:8, s. 1469-1479
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Tidskriftsartikel (refereegranskat)abstract
- Simulations of a heavy-duty diesel engine operated at high-load and low-load conditions were compared to each other, and experimental data in order to evaluate the influence of turbulence–chemistry interactions on heat release, pressure development, flame structure, and temperature development are quantified. A recently developed new combustion model for turbulent diffusion flames called representative interactive linear eddy model which features turbulence–chemistry interaction was compared to a well-stirred reactor model which neglects the influence of turbulent fluctuations on the mean reaction rate. All other aspects regarding the spray combustion simulation like spray break-up, chemical mechanism, and boundary conditions within the combustion chamber were kept the same in both simulations. In this article, representative interactive linear eddy model is extended with a progress variable, which enables the model to account for a flame lift-off and split injection, when it is used for diffusion combustion. In addition, the extended version of representative interactive linear eddy model offers the potential to treat partially premixed and premixed combustion as well. The well-stirred reactor model was tuned to match the experimental results, thus computed pressure and apparent heat release are in close agreement with the experimental data. Representative interactive linear eddy model was not tuned specifically for the case and thus the computed results for pressure and heat release are in reasonable agreement with experimental data. The computational results show that the interaction of the turbulent flow field and the chemistry reduce the peak temperatures and broaden up the turbulent flame structure. Since this is the first study of a real combustion engine (metal engine) with the newly developed model, representative interactive linear eddy model appears as a promising candidate for predictions of spray combustion in engines, especially in combustion regimes where turbulence–chemistry interaction plays an even more important role like, example given, in low-temperature combustion or combustion with local extinction and re-ignition.
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22. |
- Lagercrantz, Anne, et al.
(författare)
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Källkritik och krig : propaganda, desinformation och lögner
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Krigsrapporteringen från Ukraina utmanar redaktionernas resurser för att kontrollera vad som är sant och falskt. I rapporten Källkritik och krig presenteras en granskning av hur redaktionerna hanterar desinformation och säkerställer trovärdighet i svenska mediers rapportering under krigets sex första veckor. Slutsatsen är att det är ovanligt att redaktionerna verifierar den egna rapporteringen, vilket istället överlåts på utländska nyhetsbyråer och medier. Den övervägande delen av den svenska bevakningen görs på distans.Rapporten visar också hur Ryssland sedan flera år systematiskt skadar, smädar och styr bilden av Sverige. En direktrapport från Ukraina ger en inblick i hur oklar strategin är för den inhemska bevakningen av kriget.Institutet för mediestudier vill med den här rapporten fördjupa diskussionen om källkritik och faktagranskning i krigs- och konfliktapportering.
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23. |
- Larsson, Ingrid, 1968-, et al.
(författare)
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Sleep interventions for children with attention deficit hyperactivity disorder (ADHD) : A systematic literature review
- 2023
-
Ingår i: Sleep Medicine. - Amsterdam : Elsevier. - 1389-9457 .- 1878-5506. ; 102, s. 64-75
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Forskningsöversikt (refereegranskat)abstract
- Objective/background: Healthy sleep is particularly important for children with attention deficit hyperactivity disorder (ADHD), as sleep disturbances might aggravate disease symptoms. This review aims to synthesize and report evidence on the effectiveness of sleep interventions in increasing sleep, quality of life (QoL), and ADHD symptoms among children with ADHD. Patients/methods: The systematic literature review follows the Cochrane Collaboration methodology recommendations for literature reviews. Four databases were used based on the population, intervention, control and outcome (PICO) framework. Controlled trials with minimum 20 children in each group, aged 6–18, and published from 2005 and onwards were included. Results from the studies were reported in forest plots and three of the seven review outcomes were synthesized in meta-analyses. Results: The search identified 7710 records; of which 4808 abstracts were screened. After fulltext-screening of 99 papers, eight papers from five studies were included. The studies included behavioral sleep interventions and pharmacological interventions using melatonin and eszopiclone. For six of the seven outcomes, the effect sizes were small to moderate and the certainty of the evidence was low. For one outcome, sleep disturbances, the effect size was a moderate −0.49 standardized mean differences (95% confidence interval −0.65;-0.33), with a moderate certainty of evidence for the behavioral interventions for children aged 5–13 years with ADHD. Conclusions: This review identified few and heterogeneous studies. A moderate certainty of evidence for a moderate effect size was only obtained for sleep disturbances from the behavioral interventions. A low certainty of the evidence for a moderate effect size was found for the total sleep time from the pharmacological intervention using melatonin and one behavioral intervention, which indicates that these sleep interventions impact sleep quantity and quality among children with ADHD. © 2022 The Authors
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24. |
- Leblond, Claire S, et al.
(författare)
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Genetic and functional analyses of SHANK2 mutations suggest a multiple hit model of autism spectrum disorders.
- 2012
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 8:2
-
Tidskriftsartikel (refereegranskat)abstract
- Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disorders with a complex inheritance pattern. While many rare variants in synaptic proteins have been identified in patients with ASD, little is known about their effects at the synapse and their interactions with other genetic variations. Here, following the discovery of two de novo SHANK2 deletions by the Autism Genome Project, we identified a novel 421 kb de novo SHANK2 deletion in a patient with autism. We then sequenced SHANK2 in 455 patients with ASD and 431 controls and integrated these results with those reported by Berkel et al. 2010 (n=396 patients and n=659 controls). We observed a significant enrichment of variants affecting conserved amino acids in 29 of 851 (3.4%) patients and in 16 of 1,090 (1.5%) controls (P=0.004, OR=2.37, 95% CI=1.23-4.70). In neuronal cell cultures, the variants identified in patients were associated with a reduced synaptic density at dendrites compared to the variants only detected in controls (P=0.0013). Interestingly, the three patients with de novo SHANK2 deletions also carried inherited CNVs at 15q11-q13 previously associated with neuropsychiatric disorders. In two cases, the nicotinic receptor CHRNA7 was duplicated and in one case the synaptic translation repressor CYFIP1 was deleted. These results strengthen the role of synaptic gene dysfunction in ASD but also highlight the presence of putative modifier genes, which is in keeping with the "multiple hit model" for ASD. A better knowledge of these genetic interactions will be necessary to understand the complex inheritance pattern of ASD.
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25. |
- Marko, Leo, 1988-
(författare)
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Live Sense : Rethinking Liveness through Zeami's Concept of the Flower
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The term live is generally understood in the sense of “immediate,” or to indicate the fact that something takes place here and now. The fact that some events are perceived as live undoubtedly indicates something significant about those events. Still, scholarship in performance studies and neighboring fields have demonstrated that a simple, ontological, or technical definition of liveness is problematic if not impossible. This study rethinks the meaning of liveness, proposing that liveness pertains to the manner in which something is perceived and to what is perceived in that thing. Based on a reassessment of key conceptualizations of liveness and presence in performance studies, it develops an understanding of liveness as the characteristic of a sense-making that affirms difference, and which presupposes mediation rather than implying immediacy. The dynamics of this live sense are further developed through a consideration of the artistic treatises of Japanese nō actor and playwright Zeami (c. 1363 – c. 1443). These texts demonstrate how secrecy or not knowing is a precondition to produce a sense of liveness for the audience, expressed by the concept hana, the “flower.” The dissertation argues that this sense of secrets is significant for the artistic process as well, and that it relates to larger questions regarding understanding, aesthetics and the nature of reality. Then in the last chapter, the study takes up three examples of film, nō theater and pop music, exploring how a liveness that is objective and universal comes to be experienced subjectively in particular encounters of different kinds. In this way, the thesis as a whole provides a way of understanding liveness as the appreciation of the ineffable: a theoretical framework which serves both to analyze specific experiences and to shed light on the live foundation of sense-making as such.
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26. |
- Millinger, Johan, 1978, et al.
(författare)
-
Arterial Blood Flow and Effects on Limb Tissue Perfusion During Endoshunting of the Common Iliac Artery in an Experimental Porcine Model
- 2024
-
Ingår i: EJVES VASCULAR FORUM. - 2666-688X. ; 61, s. 54-61
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Temporary arterial shunting is an established method to prevent tissue ischaemia. Although less well established, shunting might also be achieved through endovascular and hybrid techniques, known as endoshunting. Endoshunting offers advantages, for example, enabling minimally invasive access and avoiding complete occlusion of the donor artery. In an ex vivo bench test, volume flow in various interconnected endoshunt systems has been tested previously. This study aimed to investigate the capacity of the best performing endoshunt system in vivo. Methods: Six anaesthetised pigs had their common iliac arteries (CIAs) explored, with the left CIA serving as the experimental and the right CIA as the control. Mean arterial pressure, regional blood flow, endoshunt flow, and regional oxygen extraction and lactate production were recorded. Distal muscle perfusion was monitored using near infrared spectroscopy (NIRS). Each experiment involved baseline registration, cross clamping of the left CIA, a 120 minute endoshunt session, and restoration of native flow. Results: During cross clamping, NIRS values on the experimental side reached the lowest measurable value. Following endoshunt activation, there were no NIRS value differences between the experimental and control extremities whereas the average arterial flow decreased in both the experimental (270-140 mL/min, p = .028) and control extremities (245-190 mL/min, p = .25), with a greater drop on the endoshunted side (48% vs. 22%, respectively). Lactate levels temporarily increased by 42% in the endoshunted limb on endoshunt activation but were normalised within an hour. Oxygen extraction remained constant at 55% on the control side but increased to 70% on the endoshunted side (p = .068). Conclusion: In this animal model, a flow optimised endoshunt system appeared to provide sufficient blood flow and restored stable tissue perfusion. Although arterial flow was slightly lower and oxygen extraction slightly higher on the endoshunted side, the endoshunt seemed to deliver adequate perfusion to prevent significant ischaemia.
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27. |
- Millinger, Johan, 1978, et al.
(författare)
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Optimisation of Volume Flow Rates when Using Endovascular Shunting Techniques: An Experimental Study in Different Bench Flow Circuits
- 2023
-
Ingår i: EJVES Vascular Forum. - : Elsevier BV. - 2666-688X. ; 58, s. 5-10
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Acute tissue ischaemia may arise due to arterial emergencies or during more complex vascular procedures and may be mitigated by temporary shunting techniques. Endovascular shunting (ES) techniques enable percutaneous access and shunting from the donor artery without the need to completely interrupt the arterial flow in the donor artery. An endoshunt system may also cover longer distances than most conventional shunts. The aim was to investigate and optimise the flow rates in different endovascular shunt systems.Methods: Step 1: The flow capacity of different ES configurations was compared with the flow capacity of a 9 Fr Pruitt-Inahara shunt (PIS). An intravenous bag with 0.9% NaCl, pressurised to 90 mmHg, was connected simultaneously to a PIS and to one of the tested ES configurations. The two shunt systems were then opened at the same time. The delivered fluid volumes from the shunt systems were collected and measured. The volume flow rate was subsequently calculated. Steps 2 and 3: Within a heart lung machine circuit, pressure -flow charts were constructed for the individual ES components and for the fully connected optimised endoshunt systems. The flow rate was increased in steps of 40-50 mL/min while monitoring the driving pressure, enabling the creation and comparison of the pressure -flow charts for the individually tested components. In total, seven individual inflow and outflow potential ES components were investigated with inflow and outflow diameters ranging from 6 to 15 Fr.Results: ES systems based on standard donor introducers led to substantially lower volume flow than the corresponding PIS volume flow, whereas ES systems based on dedicated 6 or 8 Fr dialysis access introducers (Prelude Short Sheet, Merit Medical) matched PIS flow rates. The introduction of 30 cm long 1/400 perfusion tubing within the ES system did not affect volume flow for any of the tested ES configurations.Conclusion: Endoshunting techniques can match PIS volume flow rates over short and long distances. The achieved ES flow rate is highly dependent on the components used within the ES system.
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28. |
- Nygren, Andreas, 1990, et al.
(författare)
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A study of ECN spray a using an improved stochastic blob (VSB2) spray model
- 2020
-
Ingår i: ICLASS 2018 - 14th International Conference on Liquid Atomization and Spray Systems.
-
Konferensbidrag (refereegranskat)abstract
- Accurate prediction of spray formation is crucial when modeling spray combustion. In this work an existing Eulerian-Lagrangian spray model, VSB2 has been extended to account for secondary break-up in a more accurate way, by creating child blobs from the stripped of mass for each blob undergoing break up. The new break-up approach was compared with the old approach for two different parametric variations of the ECN spray A refer- ence case. It showed that the new method predicted more accurate liquid penetration with the effect being more pronounced at lower ambient temperature. It was concluded that with the new break up treatment, smaller blobs from the stripped off mass is created downstream of the spray, causing the liquid to evaporate faster as the smaller blobs with less momentum have an increased radial dispersion into the bulk as they will be affected more by the drag force. More heat is available to evaporate the fuel outside in the bulk. A reduction in turbulence was also observed due to the smoother velocity gradients generated by the smaller blobs.
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29. |
- Nygren, Andreas, 1967, et al.
(författare)
-
Autoregulation of human jejunal mucosal perfusion during cardiopulmonary bypass.
- 2006
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Ingår i: Anesthesia and analgesia. - 1526-7598. ; 102:6, s. 1617-22
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Tidskriftsartikel (refereegranskat)abstract
- Animal studies have suggested that autoregulation of intestinal blood flow is severely impaired during cardiopulmonary bypass (CPB). We investigated the jejunal mucosal capacity to autoregulate perfusion during nonpulsatile CPB (34 degrees C) in 10 patients undergoing elective cardiac surgery. Changes in mean arterial blood pressure (MAP) were induced by altering the CPB flow rate randomly for periods of 3 min from 2.4 L/min/m2 to either 1.8 or 3.0 L/min/m2. Jejunal mucosal perfusion (JMP) was continuously recorded by laser Doppler flowmetry. A typical pattern of flow motion (vasomotion) was recorded in all patients during CPB. Variations in CPB flow rates caused no significant changes in mean JMP, jejunal mucosal hematocrit, or red blood cell velocity within a range of MAP from 50 +/- 15 to 74 +/- 16 mm Hg. The vasomotion frequency and amplitude was positively correlated with CPB flow rate. IV injections of prostacyclin (10 microg, Flolan) blunted vasomotion and increased JMP from 192 +/- 53 to 277 +/- 70 (P < 0.05) perfusion units despite a reduction in MAP from 59 +/- 12 to 45 +/- 10 mm Hg (P < 0.05). Prostacyclin-induced vasodilation resulted in loss of mucosal autoregulation (pressure-dependent perfusion). We conclude that autoregulation of intestinal mucosal perfusion is maintained during CPB in humans.
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30. |
- Nygren, Andreas, 1990
(författare)
-
CFD Modeling of an Alcohol-Diesel Direct-Injection Dual-Liquid-Fuel Engine using OpenFOAM
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Legislation for heavy duty combustion engines are becoming more stringent. To keep up with the legislation, new engine technology is required. Furthermore, renewable fuels can also be used together with new engine technology to further reduce emissions. Computational techniques such as Computational Fluid Dynamics (CFD) provides a powerful and cost effective alternative/complement to traditional engine tests when developing new engine technology. To effectively use CFD for engine development, accurate models for spray formation and chemistry are required. In this work a new direct-injection dual-liquid-fuel engine concept using methanol and diesel was investigated using CFD. The first part of this thesis involved validation and development of our in-house spray model, VSB2. The VSB2 is a Eulerian-Lagrangian model with a minimal amount of tuning parameter. It models the impact of secondary breakup by including a distribution of droplet sizes inside each computational blob. The model was first validated for use with alcohol fuels, where the turbulence parameters were also tuned together with experimental data for later use in engine simulations. It was shown that the VSB2 spray model could accurately predict the spray formation of an alcohol spray. Furthermore, the spray model was developed further by implementing a new break up treatment that addressed some conceptual flaws in how the model handles the momentum of a computational blob with different droplet sizes. Previously, each computational blob contained the momentum of all droplet sizes, which had the consequence that smaller droplets would have the same momentum as larger droplets. This was addressed by creating child blobs from the stable droplet sizes. It was shown that this had the effect of enhancing the evaporation and dispersion at lower ambient gas temperatures. The last part of this thesis was to create a CFD model in OpenFOAM that could model a direct-injection dual-liquid-fuel engine. A tabulated chemistry solver based on the well stirred reactor approach called LOGE-CPV was used to model the chemistry. It was shown that the model could accurately predict global parameters such as in cylinder pressure and rate of heat release of the system, but pollutant formation was predicted poorly when compared to experiments. It was concluded that a turbulent combustion model would be needed to accurately predict pollutant formation. The ignition process was also studied, showing that the pilot diesel could easily ignite the methanol as long as the pilot flame would reach the center of the combustion chamber. It was also shown that further offsetting the pilot injector caused the combustion to become unstable as it was difficult to ignite all the sprays from the main injector.
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31. |
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32. |
- Nygren, Andreas
(författare)
-
Hadronic Structure Measurements of the Photon by DELPHI at LEP II
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is mainly an analysis of data taken by the VSAT detector in the DELPHI experiment at the LEP II collider at CERN. The analysis spans from 1998 to 2000, with a center of mass energy ranging from 189 to 206 GeV. The VSAT calorimeter was constructed to be a luminosity and background monitor for the DELPHI experiment, and a full description of the luminosity and background analysis for the LEP II conditions is presented. The VSAT detector is located in the very forward direction and covers angles between three and eight milliradians since 1998. This also makes the detector to an excellent tool for studying two photon physics, as the outgoing electrons from a two-photon collision mainly are located at small angles. A full study of the VSAT double tag data between 1998 and 2000 is presented. Gamma-gamma collisions with an invariant mass reaching up to 100 GeV could be explored in a Q2 range of 0.2-0.8 GeV. With help of data from the STIC detector,which is located at larger polar angles, two photon collisions could also be probed with a Q2 between 20 and 100 GeV.
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33. |
- Nygren, Andreas, 1990
(författare)
-
Modeling of Spray Formation and Development in OpenFOAM with Application to Diesel and Alcohol Fuels
- 2018
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Legislation with reagards to fuel emissions are becoming more stringent. This creates a need for improved engine concepts and fuels. This work is part of an ongoin project to create a concept for a direct injection dual fuel engine, which uses alcohol as main fuel and diesel as a pilot. The work in this thesis is part of the task to create a CFD model for this engine that can be used for improving the current engine concept. The first part of this project has been to validate the in-house spray model, VSB2 for usage with alcohol fuels. This was done by comparing simululations made in OpenFOAM with experimental data obtained from the Chalmers HT/HP spray chamber. The simulations showed that the model could capture spray penetration at the simulation conditions accurately. It was also concluded that it was neccessary to fix the turbulent length scale in the injector cell to get an accurate prediction of the liquid penetration. The second part of this project has been to improve upon the spray model. This has been done by extending the spray break up treament inside VSB2. The model was extended by implenting a mechanism for removing the stable droplets inside each blob and using these to create child parcels, containing only stable droplets. It was shown that this improves the prediction of liquid penetration, especially at lower temperatures. The Third part of this project, that is still undergoing is to do CFD simulations of a direct injection dual fuel engine. Some preliminary results are shown in this work that show good agreement in the pressure trace. The sprays also ignites in a way that is expected, with the sprays closest to the pilot igniting first. There is still some uncertainty in the results, and further studies and development are needed to produce good results.
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34. |
- Nygren, Andreas, 1967, et al.
(författare)
-
Norepinephrine and intestinal mucosal perfusion in vasodilatory shock after cardiac surgery
- 2007
-
Ingår i: Shock. - : Ovid Technologies (Wolters Kluwer Health). - 1073-2322. ; 28:5, s. 536-543
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Tidskriftsartikel (refereegranskat)abstract
- Patients with norepinephrine-dependent vasodilatory shock after cardiac surgery (n = 10) were compared with uncomplicated postcardiac surgery patients (n = 10) with respect to jejunal mucosal perfusion, gastric-arterial PCO2 gradient, and splanchnic oxygen demand/supply relationship. Furthermore, the effects of norepinephrine-induced variations in MAP on these variables were evaluated in vasodilatory shock. Norepinephrine infusion rate was randomly and sequentially titrated to target MAPs of 60, 75, and 90 mmHg (0.25 +/- 0.24, 0.37 +/- 0.21, and 0.55 +/- 0.39 mug/kg per minute, respectively). Data on jejunal mucosal perfusion, jejunal mucosal hematocrit, and red blood cell (RBC) velocity (laser Doppler flowmetry) as well as gastric-arterial PCO2 gradient (gastric tonometry) and splanchnic oxygen and lactate extraction (hepatic vein catheter) were obtained. Splanchnic oxygen extraction was 71 +/- 16% in the vasodilatory shock group and 41 +/- 9% in the control group (P < 0.001), whereas splanchnic lactate extraction did not differ between the two groups. Jejunal mucosal perfusion (61%; P < 0.001), RBC velocity (35%; P < 0.01), and arterial-gastric mucosal PCO2 gradient (150%; P < 0.001) were higher in the vasodilatory shock group compared with those of the control group. Jejunal mucosal perfusion, jejunal mucosal hematocrit, RBC velocity, arterial-gastric mucosal PCO2 gradient, splanchnic oxygen extraction, and splanchnic lactate extraction were not affected by increasing infusion rates of norepinephrine. In patients with norepinephrine-dependent vasodilatory shock after cardiac surgery, intestinal mucosal perfusion was higher, whereas splanchnic and gastric oxygen demand/supply relationships were impaired compared with postoperative controls, suggesting that intestinal mucosal perfusion is prioritized in vasodilatory shock. Increasing MAP from 60 to 90 mmHg with norepinephrine in clinical vasodilatory shock does not affect intestinal mucosal perfusion and gastric or global splanchnic oxygen demand/supply relationships.
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35. |
- Nygren, Andreas, 1967, et al.
(författare)
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Norepinephrine causes a pressure-dependent plasma volume decrease in clinical vasodilatory shock.
- 2010
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Ingår i: Acta anaesthesiologica Scandinavica. - : Wiley. - 1399-6576 .- 0001-5172. ; 54:7, s. 814-20
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Recent experimental studies have shown that a norepinephrine-induced increase in blood pressure induces a loss of plasma volume, particularly under increased microvascular permeability. We studied the effects of norepinephrine-induced variations in the mean arterial pressure (MAP) on plasma volume changes and systemic haemodynamics in patients with vasodilatory shock. METHODS: Twenty-one mechanically ventilated patients who required norepinephrine to maintain MAP > or =70 mmHg because of septic/postcardiotomy vasodilatory shock were included. The norepinephrine dose was randomly titrated to target MAPs of 60, 75 and 90 mmHg. At each target MAP, data on systemic haemodynamics, haematocrit, arterial and mixed venous oxygen content and urine flow urine were measured. Changes in the plasma volume were calculated as 100 x (Hct(pre)/Hct(post)-1)/ (1-Hct(pre)), where Hct(pre) and Hct(post) are haematocrits before and after intervention. RESULTS: Norepinephrine doses to obtain target MAPs of 60, 75 and 90 mmHg were 0.20+/-0.18, 0.29+/-0.18 and 0.42+/-0.31 microg/kg/min, respectively. From 60 to 90 mmHg, increases in the cardiac index (15%), systemic oxygen delivery index (25%), central venous pressure (CVP) (20%) and pulmonary artery occlusion pressure (33%) were seen, while the intrapulmonary shunt fraction was unaffected by norepinehrine. Plasma volume decreased by 6.5% and 9.4% (P<0.0001) when blood pressure was increased from 60 to 75 and 90 mmHg, respectively. MAP (P<0.02) independently predicted the decrease in plasma volume with norepinephrine but not CVP (P=0.19), cardiac index (P=0.73), norepinephrine dose (P=0.58) or urine flow (P=0.64). CONCLUSIONS: Norepinephrine causes a pressure-dependent decrease in the plasma volume in patients with vasodilatory shock most likely caused by transcapillary fluid extravasation.
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36. |
- Nygren, Andreas, et al.
(författare)
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Total cross-section measurements in gamma gamma collisions at very low Q(2) at LEP2
- 2002
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Ingår i: Photon 2001. - 9789812380531 ; , s. 158-161
-
Konferensbidrag (refereegranskat)abstract
- The multihadron production in the reaction e(+)e(-) -> e(+)e(-) + hadrons has been studied for the first time at LEP2 energies with both scattered e(+) and e(-) detected at very low Q(2), measured by the DELPHI VSAT. A reasonable agreement between data and full simulation is demonstrated and the total gamma gamma hadronic cross-section is estimated for the gamma gamma center of mass energy up to 100 GeV.
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37. |
- Nygren, Andreas, 1990, et al.
(författare)
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Validation of the VSB2 Spray Model for Ethanol under Diesel like Conditions
- 2017
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627. ; 2017-October
-
Tidskriftsartikel (refereegranskat)abstract
- When developing new combustion concepts, CFD simulations is a powerful tool. The modeling of spray formation is a challenging but important part when it comes to CFD modelling of non-premixed combustion. There is a large difference in the accuracy and robustness among different spray models and their implementation in different CFD codes. In the work presented in this paper a spray model, designated as VSB2 has been implemented in OpenFOAM. VSB2 differ from traditional spray models by replacing the Lagrangian parcels with stochastic blobs. The stochastic blobs consists of a droplet size distribution rather than equal sized droplets, as is the case with the traditional parcel. The VSB2 model has previously been thoroughly validated for spray formation and combustion of n-heptane. The aim of this study was to validate the VSB2 spray model for ethanol spray formation and combustion as a step in modelling dual-fuel combustion with alcohol and diesel. This was done by comparing spray penetration with data obtained from experiments with ethanol in a high-temperature high pressure spray chamber. The spray turbulence interaction is also investigated by the usage of different turbulence models. The study showed that the VSB2 model can be used to predict the formation of an ethanol spray. It was also concluded that the standard k - ε performed better than the realizable k - ε model, and that it is necessary to fix the turbulent length scale in the injector cell to produce accurate results
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38. |
- Nygren, Andreas, 1967, et al.
(författare)
-
Vasopressin decreases intestinal mucosal perfusion: a clinical study on cardiac surgery patients in vasodilatory shock.
- 2009
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Ingår i: Acta anaesthesiologica Scandinavica. - : Wiley. - 1399-6576 .- 0001-5172. ; 53:5, s. 581-8
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Low to moderate doses of vasopressin have been used in the treatment of cathecholamine-dependent vasodilatory shock in sepsis or after cardiac surgery. We evaluated the effects of vasopressin on jejunal mucosal perfusion, gastric-arterial pCO2 gradient and the global splanchnic oxygen demand/supply relationship in patients with vasodilatory shock after cardiac surgery. METHODS: Eight mechanically ventilated patients, dependent on norepinephrine to maintain mean arterial pressure (MAP) > or = 60 mmHg because of septic/post-cardiotomy vasodilatory shock and multiple organ failure after cardiac surgery, were included. Vasopressin was sequentially infused at 1.2, 2.4 and 4.8 U/h for 30-min periods. Norepinephrine was simultaneously decreased to maintain MAP at 75 mmHg. At each infusion rate of vasopressin, data on systemic hemodynamics, jejunal mucosal perfusion, jejunal mucosal hematocrit and red blood cell velocity (laser Doppler flowmetry) as well as gastric-arterial pCO2 gradient (gastric tonometry) and splanchnic oxygen and lactate extraction (hepatic vein catheter) were obtained. RESULTS: The cardiac index, stroke volume index and systemic oxygen delivery decreased and systemic vascular resistance and systemic oxygen extraction increased significantly, while the heart rate or global oxygen consumption did not change with increasing vasopressin dose. Jejunal mucosal perfusion decreased and the arterial-gastric-mucosal pCO2 gradient increased, while splanchnic oxygen or lactate extraction or mixed venous-hepatic venous oxygen saturation gradient were not affected by increasing infusion rates of vasopressin. CONCLUSIONS: Infusion of low to moderate doses of vasopressin in patients with norepinephrine-dependent vasodilatory shock after cardiac surgery induces an intestinal and gastric mucosal vasoconstriction.
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39. |
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40. |
- Nygren, Andreas, 1967, et al.
(författare)
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Vasopressors and intestinal mucosal perfusion after cardiac surgery: Norepinephrine vs. phenylephrine.
- 2006
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Ingår i: Critical care medicine. - 0090-3493. ; 34:3, s. 722-9
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To evaluate the potential differential effects of norepinephrine, an alpha1-, beta1-, and beta2-receptor agonist, to the alpha1-agonist phenylephrine on jejunal mucosal perfusion, gastric-arterial PCO2 gradient, and the global splanchnic oxygen demand-supply relationship after cardiac surgery. DESIGN: A randomized, prospective, interventional crossover study. SETTING: A university cardiothoracic intensive care unit. PATIENTS: Ten patients were studied during propofol sedation and mechanical ventilation after uncomplicated coronary artery bypass surgery. INTERVENTIONS: Each patient received randomly and sequentially norepinephrine (0.052+/-0.009 microg/kg/min) and phenylephrine (0.50+/-0.22 microg/kg/min) to increase mean arterial blood pressure by 30%. MEASUREMENTS AND MAIN RESULTS: Data on jejunal mucosal perfusion, jejunal mucosal hematocrit, and red blood cell velocity (laser Doppler flowmetry) as well as gastric-arterial Pco2 gradient (tonometry) and splanchnic oxygen extraction were obtained before (control) and during a 30-min drug infusion period after the target mean arterial blood pressure was reached. The procedure was sequentially repeated for the second vasopressor. Both drugs induced a 40-46% increase in systemic vascular resistance with no change in cardiac index. Neither jejunal mucosal perfusion, jejunal mucosal hematocrit, red blood cell velocity, nor gastric-arterial Pco2 gradient was affected by any of the vasopressors. Splanchnic oxygen extraction increased from 38.2% to 43.1% (p<.001) with norepinephrine and from 39.3% to 47.5% (p<.001) with phenylephrine. This increase was significantly more pronounced with phenylephrine compared with norepinephrine (p<.05). Mixed venous-hepatic vein oxygen saturation gradient increased with both drugs (p<.01), and the increase was more pronounced with phenylephrine (p<.05). Splanchnic lactate extraction was not significantly affected by any of the vasopressors. CONCLUSIONS: Phenylephrine induced a more pronounced global alpha1-mediated splanchnic vasoconstriction compared with norepinephrine. Neither of the vasoconstrictors impaired perfusion of the gastrointestinal mucosa in postcardiac surgery patients. The lack of norepinephrine-induced, alpha1-mediated impairment of gastrointestinal perfusion is not explained by a beta2-mediated counteractive vasodilation but instead by possible mucosal autoregulatory escape.
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41. |
- Nygren, Andreas, 1967
(författare)
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Vasopressors and intestinal mucosal perfusion. Studies in cardiac surgical and critically ill patients
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During trauma, surgery and critically illness, splanchnic ischemia and reperfusion damage maythreaten the barrier function of the intestinal mucosa, leading to bacterial translocation, immuneactivation and subsequent development of systemic inflammatory response syndrome. Detection,prevention and treatment of intestinal mucosal hypoperfusion are therefore important forprevention of complications in critically ill patients. In this thesis, the intestinal mucosalperfusion, measured by laser Doppler flowmetry, has been studied during and after cardiacsurgery and in critically ill patients with vasodilatory shock, with focus on the effects ofvasopressor treatment.The intestinal mucosal perfusion was evaluated postoperatively in eighteen cardiac surgerypatients. Elevation of the systemic perfusion pressure with norepinephrine induced no change inintestinal mucosal perfusion, whereas the combination of norepinephrine and dopamine causedincreased mucosal perfusion. Furthermore, the differential effects of phenylephrine, a pure á1-adrenoceptor agonist, and norepinephrine, which has both á1-constricting and â1- dilatingproperties, were investigated postoperatively in ten patients. Intestinal mucosal perfusion was notaltered by the vasopressors, whereas both drugs increased the global splanchnic oxygen extraction.This increase was more pronounced with phenylephrine, indicating a more pronounced globalsplanchnic vasoconstriction, compared to norepinephrine,In ten critically ill patients with multi organ failure and norepinephrine-dependentvasodilatory shock, the effects of norepinephrine-induced variations in perfusion pressure onglobal splanchnic and intestinal mucosal perfusion were evaluated. The intestinal mucosalperfusion and the global splanchnic oxygenation were not altered despite a change in meanarterial pressure from 60 to 90 mmHg.The autoregulation of intestinal mucosal perfusion during cardiopulmonary bypass wastested in ten cardiac surgery patients. Variations in perfusion pressure induced by alterations incardiopulmonary bypass flow rate revealed an intact autoregulatory capacity of the intestinalmucosa. Vasodilation with prostacyclin increased jejunal mucosal perfusion and abolished theautoregulatory capacity of the mucosa. The amplitude and frequency of the cyclic oscillation ofthe mucosal perfusion (vasomotion) increased with increasing perfusion pressureIn conclusion: Intestinal mucosal perfusion is not affected by clinical relevant doses of thevasopressors norepinephrine and phenylephrine, in postoperative patients and critically illpatients with vasodilatory shock. Phenylephrine causes a more pronounced global splanchnicvasoconstriction compared to norepinephrine. Addition of dopamine increases intestinal mucosalperfusion during norepinephrine infusion. Autoregulation of intestinal mucosal perfusion isintact during cardiopulmonary bypass.
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42. |
- Nygren, Gunnar, 1954-, et al.
(författare)
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Changing Norms Concerning Verification
- 2018
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Ingår i: Trust in Media and Journalism. - Wiesbaden : Springer. - 9783658207649 - 9783658207656 ; , s. 39-59
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Bokkapitel (refereegranskat)abstract
- Over the past decade, journalism has undergone dramatic changes as a result of digitalization and multi-platform news production. Online, news is no longer a static product, but a flow of liquid news packages under constant alteration. This chapter discusses how the digital news environment has influenced attitudes towards verification among journalists in Poland, Russia and Sweden. The analysis builds on a survey to 1500 journalists in these countries. Results show a strong support for verification in general, but the new liquid news environment has also created softer attitudes towards verification. Between 30–40 per cent of the journalists believe that the audience has lower demands on news published online. As many hold the view that verification of facts can be done during rather than before publication. The analysis also reveals important differences between organizational cultures and between countries. Broadcast journalists keep their old values of verification to a larger extent, and newspaper journalists seem to accept a higher amount of inaccuracy in online news. Journalists in Poland and Russia have softer attitudes towards verification than journalists in Sweden, reflecting a journalistic culture oriented towards opinions, in contrast to the Anglo-Saxon fact-oriented tradition that characterizes Swedish journalism.
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43. |
- Nygren, Gunnar, et al.
(författare)
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Hur vet medierna? Källkritik och desinformation i bevakningen av kriget i Ukraina 2022
- 2022
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Ingår i: Källkritik och krig. - Stockholm : Institutet för mediestudier. - 9789198709841 ; , s. 13-73
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Bokkapitel (populärvet., debatt m.m.)abstract
- Desinformation och propaganda är ett allt viktigare inslag som lyfts i bevakningen av kriget i Ukraina. Det visar en analys av nyhetsflödet i svenska medier under krigets första sex veckor. Samtidigt är det ovanligt att svenska redaktioner själva kan verifiera den egna krigsrapporteringen, istället litar de på internationella nyhetsbyråer och medier. Därför är förtroendet för nyhetsleverantörer en grundbult i bevakningen. Den här Studien kretsar kring fyra frågor: Hur beskrivs frågor runt desinformation och källkritik i nyhetsflödet? Vilka källor används i några utvalda fall – officiella källor, egna reportrar, andra medier etcetera. Finns det någon bedömning av källornas trovärdighet? I vilken grad används innehåll från sociala medier som källa och vilka typer av källor är det i så fall? I vilken grad är rapporteringen transparent när det gäller vilka källor som används och huruvida uppgifterna är verifierade/bekräftade eller inte?
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44. |
- Nygren, Gunnar, 1954-, et al.
(författare)
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Ukraina och informationskrigets nya vägar : Sociala medier, krigsrapportering och desinformation
- 2024. - 1
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Sociala medier spelar en central roll i nyhetsflödet från kriget i Ukraina. Både som källor och som plattformar för distribution och cirkulation av innehåll. I de sociala medieflödena finns viktiga vittnesskildringar från människor som befinner sig i krigets centrum, men också desinformation och konspirationsteorier. I Ukraina har den sociala medieplattformen Telegram blivit den viktigaste källan till information för många människor, trots att den har ryska rötter. Den här boken undersöker nyhetsflödet från kriget i Ukraina, men också människors medieanvändning och förtroende för den information de möter genom olika typer av medier. Den är resultatet av ett samarbete mellan svenska och ukrainska forskare som analyserat tusentals artiklar och uppdateringar på sociala medier, gjort intervjuer med medieanvändare i Ukraina, och analyserat svenska folkets nyhetskonsumtion. Allt detta lägger grunden för en analys av ett nytt och framväxande hybridmediesystem, där traditionella, alternativa, och sociala medier konkurrerar om människors uppmärksamhet, men också ger olika bilder av krigets orsaker och konsekvenser.
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45. |
- Nygren, Gunnar, 1954-, et al.
(författare)
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Ukraina och informationskrigets nya vägar : Sociala medier, krigsrapportering och desinformation
- 2024
-
Bok (övrigt vetenskapligt/konstnärligt)abstract
- Sociala medier spelar en central roll i nyhetsflödet från kriget i Ukraina. Både som källor och som plattformar för distribution och cirkulation av innehåll. I de sociala medieflödena finns viktiga vittnesskildringar från människor som befinner sig i krigets centrum, men också desinformation och konspirationsteorier. I Ukraina har den sociala medieplattformen Telegram blivit den viktigaste källan till information för många människor, trots att den har ryska rötter. Den här boken undersöker nyhetsflödet från kriget i Ukraina, men också människors medieanvändning och förtroende för den information de möter genom olika typer av medier. Den är resultatet av ett samarbete mellan svenska och ukrainska forskare som analyserat tusentals artiklar och uppdateringar på sociala medier, gjort intervjuer med medieanvändare i Ukraina, och analyserat svenska folkets nyhetskonsumtion. Allt detta lägger grunden för en analys av ett nytt och framväxande hybridmediesystem, där traditionella, alternativa, och sociala medier konkurrerar om människors uppmärksamhet, men också ger olika bilder av krigets orsaker och konsekvenser.
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46. |
- Nygren, Gunnar, et al.
(författare)
-
Varifrån får svenskarna sina nyheter om kriget i Ukraina? Om användning och förtroende i den gränslösa digitala medieekologin
- 2023
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Ingår i: Ovisshetens tid. - Göteborg : SOM-institutet, Göteborgs universitet.
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- De stora svenska nyhetsmedierna står starka hos publiken när det gäller nyhetsflödet från kriget i Ukraina. Det visar 2022 års nationella SOM-undersökning. Nästan nio av tio tar del av nyheter om kriget i de stora dagstidningarna och etermedierna minst varje vecka. Förtroendet för krigsrapporteringen i dessa medier är också högt. För de som vill fördjupa sig i nyhetsflödet visar sig tydliga skillnader både utifrån ålder och sociala faktorer. Högutbildade män i storstäder går gärna till internationella medier medan lågutbildade och äldre män i mindre tätorter gärna går till svenska alternativa nyhetssajter. Yngre åldersgrupper hittar oftast nyheter och opinionsmaterial om kriget på sociala medieplattformar, men förtroendet för dessa samt för alternativa medier är lågt. Ändå är användningen av alternativa medier högre när det gäller krigsnyheter än för generell nyhetskonsumtion, något som kan hänga ihop med en brist på mångfald i de etablerade mediernas rapportering.
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47. |
- Nygren, Kristiina, et al.
(författare)
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A comprehensive phylogeny of Neurospora reveals a link between reproductive mode and molecular evolution in fungi
- 2011
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 59:3, s. 649-663
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Tidskriftsartikel (refereegranskat)abstract
- The filamentous ascomycete genus Neurospora encompasses taxa with a wide range of reproductive modes. Sexual reproduction in this genus can be divided into three major modes; heterothallism (self-incompatibility), homothallism (self-compatibility) and pseudohomothallism (partial self-compatibility). In addition to the sexual pathway, most of the heterothallic taxa propagate with morphologically distinct, vegetative dissemination propagules (macroconidia), while this feature is undetected in the majority of the homothallic taxa. In this study, we used sequence information of seven nuclear gene loci from 43 taxa (295 of the possible 301 locus-by-taxon combinations) to create a phylogeny of Neurospora. The results suggest that transitions in reproductive mode have occurred at multiple times within this group of fungi. Although a homothallic ancestor would imply fewer switches in reproductive mode, we argue that the ancestor of Neurospora was likely heterothallic and that homothallism has evolved independently at least six times in the evolutionary history of the genus. Furthermore, the two pseudohomothallic taxa of Neurospora (N. tetrasperma and N. tetraspora) represent two independent origins of pseudohomothallism. Likelihood ratio tests of substitution rates among branches in the phylogeny indicate that reproductive mode is an important factor driving genome evolution in Neurospora. First, an increased level of non-synonymous/synonymous substitutions in branches delineating homothallic taxa was found, suggesting a reduced efficiency of purifying selection in these taxa. Furthermore, elevated nucleotide substitution rates were found in heterothallic, conidia-producing, lineages as compared to the homothallic non-conidiating lineages. The latter finding is likely due to the presence of conidia, i.e., a higher rate of mitotic divisions inducing mutations, and/or that the homothallic taxa have evolved a lower mutation rate to avoid genomic degeneration.
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48. |
- Nygren, Kristiina, et al.
(författare)
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Analyses of expressed sequence tags in Neurospora reveal rapid evolution of genes associated with the early stages of sexual reproduction in fungi
- 2012
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Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 12, s. 229-
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Tidskriftsartikel (refereegranskat)abstract
- Background: The broadly accepted pattern of rapid evolution of reproductive genes is primarily based on studies of animal systems, although several examples of rapidly evolving genes involved in reproduction are found in diverse additional taxa. In fungi, genes involved in mate recognition have been found to evolve rapidly. However, the examples are too few to draw conclusions on a genome scale. Results: In this study, we performed microarray hybridizations between RNA from sexual and vegetative tissues of two strains of the heterothallic (self-sterile) filamentous ascomycete Neurospora intermedia, to identify a set of sex-associated genes in this species. We aligned Expressed Sequence Tags (ESTs) from sexual and vegetative tissue of N. intermedia to orthologs from three closely related species: N. crassa, N. discreta and N. tetrasperma. The resulting four-species alignments provided a dataset for molecular evolutionary analyses. Our results confirm a general pattern of rapid evolution of fungal sex-associated genes, compared to control genes with constitutive expression or a high relative expression during vegetative growth. Among the rapidly evolving sex-associated genes, we identified candidates that could be of importance for mating or fruiting-body development. Analyses of five of these candidate genes from additional species of heterothallic Neurospora revealed that three of them evolve under positive selection. Conclusions: Taken together, our study represents a novel finding of a genome-wide pattern of rapid evolution of sex-associated genes in the fungal kingdom, and provides a list of candidate genes important for reproductive isolation in Neurospora.
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49. |
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50. |
- Olofsson, Anna, 1971-, et al.
(författare)
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The mutual constitution of risk and inequalities : Intersectional risk theory
- 2014
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Ingår i: Health, Risk and Society. - : Informa UK Limited. - 1369-8575 .- 1469-8331. ; 16:5, s. 417-430
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Tidskriftsartikel (refereegranskat)abstract
- In this article, we examine the conceptual importance of integrating risk and intersectionality theory for the study of how risk and various forms of inequality intersect and are mutually constitutive. We argue that an intersectional perspective can advance risk research by incorporating more effectively the role of such social categories as gender and race into the analysis of ‘risk’ as an empirical phenomenon. In doing so, the intersectional perspective articulates more clearly the connection between the social construction of risk and, on the one hand, the reproduction of new and complex social inequalities and, on the other, intersections of social class, gender, ethnicity and other social categorisations. We trace the intellectual division between risk and feminist-inspired intersectionality research, showing how these approaches can be aligned to study, for example, risk-based welfare and social policy. We use a discussion of general directions within welfare policy to illustrate how an intersectional perspective can be used to show the ways in which new governance strategies create new divisions and reproduce existing forms of social inequality. We conclude the article with a call for a new research agenda to integrate intersectional frameworks with risk theory in order to provide a more nuanced analysis of the relationship between social inequality and risk.
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