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  • 401. Debevec, T
    et al.
    Amon, M
    Keramidas, Michail E.
    KTH, School of Technology and Health (STH), Environmental Physiology (Closed 20130701).
    Kounalakis, S.N.
    Mekjavic, I.B.
    The use of live low – train high protocol for the enhancement of endurance performance and aerobic capacity.2009Conference paper (Other academic)
  • 402. Debevec, T.
    et al.
    Amon, M.
    Keramidas, Michail E.
    KTH, School of Technology and Health (STH), Environmental Physiology (Closed 20130701).
    Simunic, B.
    Pisot, R.
    Kounalakis, S.N.
    Eiken, O.
    Mekjavic, I.B.
    “Sleep high – train low” altitude training2008Conference paper (Other academic)
  • 403. Debevec, T
    et al.
    Amon, Mojca
    Keramidas, Michail E.
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Kounalakis, S.N.
    Pisot, R
    Mekjavic, I.B.
    Normoxic and hypoxic performance following four weeks of normobaric hypoxic training2010In: Aviation, Space and Environmental Medicine, ISSN 0095-6562, E-ISSN 1943-4448, Vol. 81, no 4, p. 387-393Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION:

    Although training in hypoxia has been suggested to improve sea level and altitude performance, most studies have only evaluated its effect on maximal aerobic capacity in either normoxia or hypoxia. The present study evaluated the effect of a live low-train high training regimen on both normoxic and hypoxic endurance performance and aerobic capacity.

    METHODS:

    There were 18 male subjects who performed 20 training sessions in either a normoxic (F(IO2) = 0.21) or hypoxic (F(IO2) = 0.12) environment. Both the Control (N = 9) and Hypoxic (N = 9) group subjects trained at an intensity that maintained their heart rate at a level corresponding to that elicited at 50% of peak power output attained in normoxia or hypoxia, respectively. Before, during, upon completion, and 10 d after the protocol, subjects' aerobic capacity (VO2 peak) and endurance performance (80% of VO2 peak) were determined under normoxic and hypoxic conditions.

    RESULTS:

    Mean +/- SD normoxic VO2 peak increased significantly only in the Control group from 45.7 +/- 6.1 to 53.9 +/- 3.9 (ml x kg(-1) x min(-1)), whereas hypoxic VO2 peak did not improve in either group. The Control group exhibited significant improvements in normoxic, but not hypoxic peak power output (PPO) and time to exhaustion, whereas the Hypoxic group only exhibited improvements in normoxic time to exhaustion. During each testing period, we also assessed pulmonary function, selected hematological variables, and anthropometry. There were no significant changes in these variables in either group after the training protocol.

    CONCLUSION:

    The hypoxic training regimen used in the present study had no significant effect on altitude and sea level performance.

  • 404. Debevec, T
    et al.
    Bali, T
    Simpson, E.J.
    MacDonald, I.A.
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology. KTH, School of Technology and Health (STH), Centres, Swedish Aerospace Physiology Centre, SAPC.
    Mekjavic, I.B.
    PlanHab: Effects of simulated planetary habitation on body mass and whole body composition2014Conference paper (Other academic)
  • 405. Debevec, T
    et al.
    Ehrström, S
    Pialoux, V
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology. KTH, School of Technology and Health (STH), Centres, Swedish Aerospace Physiology Centre, SAPC.
    Mekjavic, IB
    Millet, GP
    FemHab: Prooxidant/antioxidant balance during and following a 10-day hypoxic bed rest2015Conference paper (Refereed)
    Abstract [en]

    Introduction:Inhabitants of the envisaged planetary habitats will be continuously exposed to reduced gravity and hypoxia. The combined effects of unloading and hypoxia on prooxidant/antioxidant balance are currently unknown.

    Methods:Healthy female participants underwent the following three, 10-day interventions: i) Normobaric normoxic bed-rest (NBR; n=11; FiO2=0.209) ii) Normobaric hypoxic ambulatory confinement (HAMB; n=9: FiO2~0.141), and iii) Normobaric hypoxic bed-rest (HBR; n=12; FiO2~0.141). Plasma oxidative stress [advanced oxidation protein products (AOPP) and nitrotyrosine], antioxidant markers [superoxide dismutase (SOD) and glutathione peroxidase (GPX)] and nitrites were determined before (Pre), during (Day 2, Day 6), immediately after (Post) and 24-hrs after (Post+1) each campaign.

    Results:Compared to Pre, the AOPP was only higher on Day 2, Day 6 and Post during the HBR and at Post during the NBR (P<0.05) while the nitrotyrosine was significantly reduced at Post+1 only during the HAMB (P<0.05). Higher levels of SOD were observed during the HAMB at Day 6 and Post+1whereas GPX was reduced at Day 6 and Post during the HBR. Nitrites were significantly higher at Post+1 in the HAMB both, compared to Pre and compared to HBR and NBR (P<0.05).

    Conclusion:These data suggest that the unloading-induced oxidative stress is exacerbated by exposure to simulated altitude of ~4000m. In addition, even habitual (low) physical activity, performed during hypoxic exposure, seems to blunt hypoxia-related oxidative stress via antioxidant system upregulation.

  • 406. Debevec, T
    et al.
    Keramidas, Michail E.
    KTH, School of Technology and Health (STH), Environmental Physiology (Closed 20130701).
    Amon, M
    Kounalakis, S.N.
    Mekjavic, I.B.
    Evaluation of training protocols for the improvement of altitude and sea level performance2009Conference paper (Other academic)
  • 407. Debevec, T.
    et al.
    Keramidas, Michail E.
    Norman, B
    Gustafsson, T
    Eiken, Ola
    KTH, School of Technology and Health (STH), Environmental Physiology (Closed 20130701).
    Mekjavic, I
    No evidence for the “normobaric oxygen paradox”2011In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, Vol. 43, no S5, p. 151-151Article in journal (Other academic)
  • 408. Debevec, T
    et al.
    McDonnell, A.C.
    MacDonald, I
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Mekjavic, I.B.
    Changes in body composition and dietary intake as a consequence of 10-day hypoxic confinement and unloading/inactivityIn: Applied Physiology, Nutrition and Metabolism, ISSN 1715-5312, E-ISSN 1715-5320Article in journal (Refereed)
  • 409. Debevec, T.
    et al.
    Pialoux, V.
    Mekjavic, I.B.
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Mury, P.
    Millet, G.P.
    Moderate exercise blunts oxidative stress induced by normobaric hypoxic confinement2014In: Medicine & Science in Sports & Exercise, ISSN 0195-9131, E-ISSN 1530-0315, Vol. 46, no 1, p. 33-41Article in journal (Refereed)
    Abstract [en]

    PURPOSE: Both acute hypoxia and physical exercise are known to increase oxidative stress. This randomized prospective trial investigated whether the addition of moderate exercise can alter oxidative stress induced by continuous hypoxic exposure. METHODS: Fourteen male participants were confined to 10-d continuous normobaric hypoxia (FIO2 = 0.139 ± 0.003, PIO2 = 88.2 ± 0.6 mm Hg, ∼4000-m simulated altitude) either with (HCE, n = 8, two training sessions per day at 50% of hypoxic maximal aerobic power) or without exercise (HCS, n = 6). Plasma levels of oxidative stress markers (advanced oxidation protein products [AOPP], nitrotyrosine, and malondialdehyde), antioxidant markers (ferric-reducing antioxidant power, superoxide dismutase, glutathione peroxidase, and catalase), nitric oxide end-products, and erythropoietin were measured before the exposure (Pre), after the first 24 h of exposure (D1), after the exposure (Post) and after the 24-h reoxygenation (Post + 1). In addition, graded exercise test in hypoxia was performed before and after the protocol. RESULTS: Maximal aerobic power increased after the protocol in HCE only (+6.8%, P < 0.05). Compared with baseline, AOPP was higher at Post + 1 (+28%, P < 0.05) and nitrotyrosine at Post (+81%, P < 0.05) in HCS only. Superoxide dismutase (+30%, P < 0.05) and catalase (+53%, P < 0.05) increased at Post in HCE only. Higher levels of ferric-reducing antioxidant power (+41%, P < 0.05) at Post and lower levels of AOPP (-47%, P < 0.01) at Post + 1 were measured in HCE versus HCS. Glutathione peroxidase (+31%, P < 0.01) increased in both groups at Post + 1. Similar erythropoietin kinetics was noted in both groups with an increase at D1 (+143%, P < 0.01), a return to baseline at Post, and a decrease at Post + 1 (-56%, P < 0.05). CONCLUSIONS: These data provide evidence that 2 h of moderate daily exercise training can attenuate the oxidative stress induced by continuous hypoxic exposure.

  • 410. Debevec, T.
    et al.
    Simpson, E. J.
    Mekjavic, I. B.
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology. KTH, School of Technology and Health (STH), Centres, Swedish Aerospace Physiology Centre, SAPC.
    Macdonald, I. A.
    Effects of prolonged hypoxia and bed rest on appetite and appetite-related hormones2016In: Appetite, ISSN 0195-6663, E-ISSN 1095-8304, Vol. 107, p. 28-37Article in journal (Refereed)
    Abstract [en]

    Environmental hypoxia and inactivity have both been shown to modulate appetite. To elucidate the independent and combined effects of hypoxia and bed rest-induced inactivity on appetite-related hormones and subjective appetite, eleven healthy, non-obese males underwent three experimental interventions in a cross-over and randomized fashion: 1) Hypoxic confinement combined with daily moderate-intensity exercise (HAMB, FiO2 = 0.141 ± 0.004; PiO2 = 90.0 ± 0.4 mmHg) 2) Bed rest in normoxia (NBR, FiO2 = 0.209; PiO2 = 133.1 ± 0.3 mmHg) and 3) Bed rest in hypoxia (HBR, FiO2 = 0.141 ± 0.004; PiO2 = 90.0 ± 0.4 mmHg). A mixed-meal tolerance test (MTT), followed by an ad libitum meal were performed before (Pre) and after 16-days (Post) of each intervention. Composite satiety scores (CSS) during the MTT were calculated from visual analogue scores, while fasting and postprandial concentrations of total ghrelin, peptide YY (PYY), glucagon-like peptide-1 (GLP-1) and leptin were quantified from arterialized-venous samples. Postprandial CSS were significantly lower at Post compared to Pre in NBR only (P &lt; 0.05) with no differences observed in ad libitum meal intakes. Postprandial concentrations and incremental area under the curve (AUC) for total ghrelin and PYY were unchanged following all interventions. Postprandial GLP-1 concentrations were only reduced at Post following HBR (P &lt; 0.05) with resulting AUC changes being significantly lower compared to HAMB (P &lt; 0.01). Fasting leptin was reduced following HAMB (P &lt; 0.05) with no changes observed following NBR and HBR. These findings suggest that independently, 16-day of simulated altitude exposure (∼4000 m) and bed rest-induced inactivity do not significantly alter subjective appetite or ad libitum intakes. The measured appetite-related hormones following both HAMB and HBR point to a situation of hypoxia-induced appetite stimulation, although this did not reflect in higher ad libitum intakes. Clinical Trial Registration Number: NCT02293772.

  • 411. Debevec, T
    et al.
    Simpson, EJ
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology. KTH, School of Technology and Health (STH), Centres, Swedish Aerospace Physiology Centre, SAPC.
    Mekjavic, IB
    Macdonald, IA
    PlanHab: The individual and combined effects of inactivity and hypoxia on insulin resistance2015Conference paper (Refereed)
    Abstract [en]

    Inactivity is know to aggravate insulin resistance. The effects of hypoxia on insulin and glucose metabolism, on the other hand, are not completely understood.

  • 412. Debevec, T
    et al.
    Simpson, T
    MacDonald, I.A.
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology. KTH, School of Technology and Health (STH), Centres, Swedish Aerospace Physiology Centre, SAPC.
    Mekjavic, I.B.
    PlanHab: Energy expenditure and appetite sensation during hypoxic bedrest2014Conference paper (Other academic)
  • 413. Debevec, Tadej
    et al.
    Bali, Tarsi C.
    Simpson, Elizabeth J.
    Macdonald, Ian A.
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology. KTH, School of Technology and Health (STH), Centres, Swedish Aerospace Physiology Centre, SAPC.
    Mekjavic, Igor B.
    Separate and combined effects of 21-day bed rest and hypoxic confinement on body composition2014In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 114, no 11, p. 2411-2425Article in journal (Refereed)
    Abstract [en]

    This study tested the hypothesis that hypoxia exacerbates reductions in body mass observed during unloading. To discern the separate and combined effects of simulated microgravity and hypoxia, 11 healthy males underwent three 21-day campaigns in a counterbalanced fashion: (1) normoxic bed rest (NBR; FiO2 = 0.209; PiO2 = 133.1 +/- A 0.3); (2) hypoxic ambulatory confinement (HAMB; FiO2 = 0.141 +/- A 0.004; PiO2 = 90.0 +/- A 0.4; similar to 4,000 m); and (3) hypoxic bed rest (HBR; FiO2 = 0.141 +/- A 0.004; PiO2 = 90.0 +/- A 0.4). The same dietary menu was applied in all campaigns. Targeted energy intakes were estimated individually using the Harris-Benedict equation taking into account whether the subjects were bedridden or ambulatory. Body mass and water balance were assessed throughout the campaigns. Whole body and regional body composition was determined before and after the campaigns using dual-energy X-ray absorptiometry. Before and during the campaigns, indirect calorimetry and visual analogue scores were employed to assess the resting energy expenditure (REE) and perceived appetite sensations, respectively. Energy intakes were lower than targeted in all campaigns (NBR: -5 %; HAMB: -14 %; HBR: -6 %; P < 0.01). Body mass significantly decreased following all campaigns (NBR: -3 %; HAMB: -4 %; HBR: -5 %; P < 0.01). While fat mass was not significantly altered, the whole body fat free mass was reduced (NBR: -4 %; HAMB: -5 %; HBR: -5 %; P < 0.01), secondary to lower limb fat-free mass reduction. Water balance was comparable between the campaigns. No changes were observed in REE and perceived appetite. Exposure to simulated altitude of similar to 4,000 m does not seem to worsen the whole body mass and fat-free mass reductions or alter resting energy expenditure and appetite during a 21-day simulated microgravity.

  • 414. Debevec, Tadej
    et al.
    Keramidas, Michail E.
    Norman, Barbara
    Gustafsson, Thomas
    Eiken, Ola
    KTH, School of Technology and Health (STH), Environmental Physiology (Closed 20130701).
    Mekjavic, Igor B.
    Acute short-term hyperoxia followed by mild hypoxia does not increase EPO production: resolving the "normobaric oxygen paradox''2012In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 112, no 3, p. 1059-1065Article in journal (Refereed)
    Abstract [en]

    Recent findings suggest that besides renal tissue hypoxia, relative decrements in tissue oxygenation, using a transition of the breathing mixture from hyperoxic to normoxic, can also stimulate erythropoietin (EPO) production. To further clarify the importance of the relative change in tissue oxygenation on plasma EPO concentration [EPO], we investigated the effect of a consecutive hyperoxic and hypoxic breathing intervention. Eighteen healthy male subjects were assigned to either IHH (N = 10) or CON (N = 8) group. The IHH group breathed pure oxygen (F(i)O(2) ~ 1.0) for 1 h, followed by a 1-h period of breathing a hypoxic gas mixture (F(i)O(2) ~ 0.15). The CON group breathed a normoxic gas mixture (F(i)O(2) ~ 0.21) for the same duration (2 h). Blood samples were taken just before, after 60 min, and immediately after the 2-h exposure period. Thereafter, samples were taken at 3, 5, 8, 24, 32, and 48 h after the exposure. During the breathing interventions, subjects remained in supine position. There were significant increases in absolute [EPO] within groups at 8 and 32 h in the CON and at 32 h only in the IHH group. No significant differences in absolute [EPO] were observed between groups following the intervention. Relative (∆[EPO]) levels were significantly lower in the IHH than in the CON group, 5 and 8 h following exposure. The tested protocol of consecutive hyperoxic-hypoxic gas mixture breathing did not induce [EPO] synthesis stimulation. Moreover, the transient attenuation in ∆[EPO] in the IHH group was most likely due to a hyperoxic suppression. Hence, our findings provide further evidence against the "normobaric O(2) paradox" theory.

  • 415. Debevec, Tadej
    et al.
    McDonnell, Adam C.
    Macdonald, Ian A.
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Mekjavic, Igor B.
    Whole body and regional body composition changes following 10-day hypoxic confinement and unloading-inactivity2014In: Applied Physiology, Nutrition and Metabolism, ISSN 1715-5312, E-ISSN 1715-5320, Vol. 39, no 3, p. 386-395Article in journal (Refereed)
    Abstract [en]

    Future planetary habitats will expose inhabitants to both reduced gravity and hypoxia. This study investigated the effects of short-term unloading and normobaric hypoxia on whole body and regional body composition (BC). Eleven healthy, recreationally active, male participants with a mean (SD) age of 24 (2) years and body mass index of 22.4 (3.2) kg.m(-2) completed the following 3 10-day campaigns in a randomised, cross-over designed protocol: (i) hypoxic ambulatory confinement (HAMB; FIO2 = 0.147 (0.008); PIO2 = 93.8 (0.9) mm Hg), (ii) hypoxic bed rest (HBR; FIO2 = 0.147 (0.008); PIO2 = 93.8 (0.9) mm Hg), and (iii) normoxic bed rest (NBR; FIO2 = 0.209; PIO2 = 133.5 (0.7) mmHg). Nutritional requirements were individually precalculated and the actual intake was monitored throughout the study protocol. Body mass, whole body, and regional BC were assessed before and after the campaigns using dual-energy X-ray absorptiometry. The calculated daily targeted energy intake values were 2071 (170) kcal for HBR and NBR and 2417 (200) kcal for HAMB. In both HBR and NBR campaigns the actual energy intake was within the targeted level, whereas in the HAMB the intake was lower than targeted (-8%, p < 0.05). Body mass significantly decreased in all 3 campaigns (-2.1%, -2.8%, and -2.0% for HAMB, HBR, and NBR, respectively; p < 0.05), secondary to a significant decrease in lean mass (-3.8%, -3.8%, -4.3% for HAMB, HBR, and NBR, respectively; p < 0.05) along with a slight, albeit not significant, increase in fat mass. The same trend was observed in the regional BC regardless of the region and the campaign. These results demonstrate that, hypoxia per se, does not seem to alter whole body and regional BC during short-term bed rest.

  • 416. Debevec, Tadej
    et al.
    Pialoux, Vincent
    Ehrström, Sabine
    Ribon, Alexandra
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Mekjavic, Igor B.
    Millet, Gregoire P.
    FemHab: The effects of bed rest and hypoxia on oxidative stress in healthy women2016In: Journal of applied physiology, ISSN 8750-7587, E-ISSN 1522-1601, Vol. 120, no 8, p. 930-938Article in journal (Refereed)
    Abstract [en]

    Independently, both inactivity and hypoxia augment oxidative stress. This study, part of the FemHab project, investigated the combined effects of bed rest-induced unloading and hypoxic exposure on oxidative stress and antioxidant status. Healthy, eumenorrheic women were randomly assigned to the following three 10-day experimental interventions: normoxic bed rest (NBR; n = 11; PIO2 = 133 mmHg), normobaric hypoxic bed rest (HBR; n = 12; PIO2 = 90 mmHg), and ambulatory hypoxic confinement (HAMB; n = 8: PIO2 = 90 mmHg). Plasma samples, obtained before (Pre), during (D2, D6), immediately after (Post) and 24 h after (Post + 1) each intervention, were analyzed for oxidative stress markers [advanced oxidation protein products (AOPP), malondialdehyde (MDA), and nitrotyrosine], antioxidant status [ superoxide dismutase (SOD), catalase, ferric-reducing antioxidant power (FRAP), glutathione peroxidase (GPX), and uric acid (UA)], NO metabolism end-products (NOx), and nitrites. Compared with baseline, AOPP increased in NBR and HBR on D2 (+ 14%; + 12%; P < 0.05), D6 (+ 19%; + 15%; P < 0.05), and Post (+ 22%; + 21%; P < 0.05), respectively. MDA increased at Post + 1 in NBR (+ 116%; P < 0.01) and D2 in HBR (+114%; P < 0.01) and HAMB (+ 95%; P < 0.05). Nitrotyrosine decreased (-45%; P < 0.05) and nitrites increased (+46%; P < 0.05) at Post + 1 in HAMB only. Whereas SOD was higher at D6 (+ 82%) and Post + 1 (+ 67%) in HAMB only, the catalase activity increased on D6 (128%) and Post (146%) in HBR and HAMB, respectively (P < 0.05). GPX was only reduced on D6 (- 20%; P < 0.01) and Post (- 18%; P < 0.05) in HBR. No differences were observed in FRAP and NOx. UA was higher at Post in HBR compared with HAMB (P < 0.05). These data indicate that exposure to combined inactivity and hypoxia impairs prooxidant/antioxidant balance in healthy women. Moreover, habitual activity levels, as opposed to inactivity, seem to blunt hypoxia-related oxidative stress via antioxidant system upregulation.

  • 417. Debevec, Tadej
    et al.
    Simpson, Elizabeth J.
    Macdonald, Ian A.
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Mekjavic, Igor B.
    Exercise Training during Normobaric Hypoxic Confinement Does Not Alter Hormonal Appetite Regulation2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 6, p. e98874-Article in journal (Refereed)
    Abstract [en]

    Background: Both exposure to hypoxia and exercise training have the potential to modulate appetite and induce beneficial metabolic adaptations. The purpose of this study was to determine whether daily moderate exercise training performed during a 10-day exposure to normobaric hypoxia alters hormonal appetite regulation and augments metabolic health. Methods: Fourteen healthy, male participants underwent a 10-day hypoxic confinement at,4000 m simulated altitude (FIO2 = 0.139 +/- 0.003%) either combined with daily moderate intensity exercise (Exercise group; N = 8, Age = 25.8 +/- 2.4 yrs, BMI = 22.9 +/- 1.2 kg.m(-2)) or without any exercise (Sedentary group; N = 6 Age = 24.8 +/- 3.1 yrs, BMI = 22.3 +/- 2.5 kg.m(-2)). A meal tolerance test was performed before (Pre) and after the confinement (Post) to quantify fasting and postprandial concentrations of selected appetite-related hormones and metabolic risk markers. C-13-Glucose was dissolved in the test meal and (CO2)-C-13 determined in breath samples. Perceived appetite ratings were obtained throughout the meal tolerance tests. Results: While body mass decreased in both groups (-1.4 kg; p = 0.01) following the confinement, whole body fat mass was only reduced in the Exercise group (-1.5 kg; p = 0.01). At Post, postprandial serum insulin was reduced in the Sedentary group (-49%; p = 0.01) and postprandial plasma glucose in the Exercise group (-19%; p = 0.03). Fasting serum total cholesterol levels were reduced (-12%; p = 0.01) at Post in the Exercise group only, secondary to low-density lipoprotein cholesterol reduction (-16%; p = 0.01). No differences between groups or testing periods were noted in fasting and/or postprandial concentrations of total ghrelin, peptide YY, and glucagon-like peptide-1, leptin, adiponectin, expired (CO2)-C-13 as well as perceived appetite ratings (p>0.05). Conclusion: These findings suggest that performing daily moderate intensity exercise training during continuous hypoxic exposure does not alter hormonal appetite regulation but can improve the lipid profile in healthy young males.

  • 418.
    Dellve, Lotta
    KTH, School of Technology and Health (STH), Ergonomics (Closed 20130701).
    Hållbart chefskap i hälso- och sjukvården - med vinjetter om engagemang, stress, tidsanvändning, medarbetarskap och vårdpraktik2012Other (Other (popular science, discussion, etc.))
  • 419.
    Dellve, Lotta
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Imbalanced logics of communicating with media in open management of health care service in Sweden: the managers perspectives and approaches2014Conference paper (Other academic)
  • 420.
    Dellve, Lotta
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Studiematerial: Hållbart chefskap i hälso- och sjukvården - med vinjetter om engagemang, stress, tidsanvändning, medarbetarskap och vårdpraktik2012Collection (editor) (Other academic)
    Abstract [sv]

    Detta är ett studiematerial som syftar till att stödja chefer i det vardagliga arbetet med avseende på hållbart ledarskap, chefskap och tidsanvändning. Med hållbarhet menar vi utifrån både verksamhets- och individ-/hälsoperspektiv. Studiematerialet kan användas för analys, reflektion och utveckling av ledarskap och chefskap.

  • 421.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Ahlborg, Tone
    Sahlgrenska Akademin, Göteborgs Universitet.
    Partner relationships and long-term sick leave among female workers: consequences and impact on dimensions of health and return to work2012In: Scandinavian Journal of Caring Sciences, ISSN 0283-9318, E-ISSN 1471-6712, Vol. 26, no 4, p. 720-729Article in journal (Refereed)
    Abstract [en]

    Few efforts have been made to prospectively identify resources and obstacles outside work that may predict regained work ability and return to work when workers are on sick leave. This study investigates the association between partner relationships and sick leave. Our research questions were as follows: (i) What is the influence of sick leave, pain, stress and domestic strain on the quality of the dyadic partner relationship?, and (ii) What is the influence of the partner and social relationship on pain, stress, work ability, self-rated health and return to work? A cohort of female workers (n = 225) on long-term sick leave (>60 days), all in a partner relationship, at 6-month intervals completed a questionnaire based on the Quality of Dyadic Relationship (QDR) instrument, the Interview Schedule of Social Interaction (ISSI), the Work Ability Index (WAI) and the Copenhagen Psychosocial Questionnaire (COPSOQ). Univariate and multivariate analyses of baseline and prospective data were performed. The results showed that decreased partner relationship quality was related to having major responsibility for household work despite being on sick leave, having pain and having decreased social integration. Among younger individuals on sick leave, a reduction in the quality of the partner relationship was shown already at the first (6-month) follow-up, while among middle-aged women, such a reduction was seen only at the 12-month follow-up. No dimensions of partner relationship quality at baseline were related to dimensions of return to work, either as a resource or as an obstacle. Consequently, our results show that a good relationship does not keep the woman from returning to work. Having main responsibility for household work, which implies domestic strain while on sick leave, predicts lower partner relationship quality. The practical implications are that healthcare professionals treating women on sick leave should emphasize the importance of keeping a social network as well as making sufficient adjustments at home for the relationship quality to be safeguarded. Special attention should be given to the young woman on sick leave as being on sick leave seems to influence her partner relationship considerably.

  • 422.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Andreasson, Jörgen
    KTH.
    Eriksson, Andrea
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Strömgren, Marcus
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Williamsson, Anna
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Nyorientering av svensk sjukvård: Verksamhetstjänande implementeringslogiker bygger mer hållbart engagemang och utveckling - i praktiken2016Report (Other academic)
  • 423.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Andreasson, Jörgen
    KTH, School of Technology and Health (STH), Health Systems Engineering.
    Jutengren, Göran
    Högskolan Borås.
    Hur kan stödresurser understödja hållbart ledarskap bland chefer i vården?2013In: Socialmedicinsk Tidskrift, ISSN 0037-833X, Vol. 90, no 6Article in journal (Refereed)
    Abstract [sv]

    Chefer kan ha stor betydelse för anställdas hälsa, stress, engagemang i arbetet och prestation. Få tidigare studier har undersökt vilket stöd chefer behöver för ett hållbart och bra ledarskap. Artikeln presenterar resultat från en prospektiv studie om betydelsen av chefers stödresurser för hållbart ledarskap. I studien, som är en del av Chefios-projektet, ingår chefer i kommunal vård och omsorg (n=344). Data från enkätstudier med instrumentet ”Gothenburg Manager Stress Inventory” har analyserats. Resultatet visar att ett stödjande privatliv och en personlig inställning till chefsuppdrag har stor betydelse för chefers hållbarhet över tid. Chefens kontrollspann och erfarenhet som chef påverkade betydelsen av stödresurser. För chefer med kortare chefserfarenhet eller fler underställda (>30) har även stöd från ledning, chefskollegor och externt stöd betydelse.

  • 424.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Eriksson, Andrea
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    ETT ARBETSMATERIAL FÖR ATT STÖDJA Hållbart och hälsofrämjande ledarskap i vardag och förändring2016Report (Other academic)
  • 425.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Eriksson, Andrea
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Health-Promoting Managerial Work: A Theoretical Framework for a Leadership Program that Supports Knowledge and Capability to Craft Sustainable Work Practices in Daily Practice and During Organizational Change2017In: Societies, ISSN 1090-9389, E-ISSN 2075-4698, Vol. 7, no 2, article id 12Article in journal (Refereed)
    Abstract [en]

    The aim of this article is to describe a theoretical framework, i.e., theoretical underpinnings and pedagogical principles, for leadership programs that support managers' evidence-based knowledge of health-promoting psychosocial work conditions, as well as their capability to apply, adapt, and craft sustainable managerial work practices. First, the theoretical framing is introduced, i.e., a system theory that integrates key work conditions with a practical perspective on managerial work and organization. Second, pedagogical principles and measures for leaders' training in integrated handling across system levels are described. Last, we present summarized results from an intervention study applying the theoretical framework and pedagogical principles. The complexity of interactions among different factors in a work system, and the variety in possible implementation approaches, presents challenges for the capability of managers to craft sustainable and health-promoting conditions, as well as the evaluation of the program components. Nevertheless, the evaluation reveals the strength of the program, in providing holistic and context-sensitive approaches for how to train and apply an integrative approach for improving the work environment.

  • 426.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Eriksson, Andrea
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Hållbart ledarskap - I vardag och förändring2016Report (Other academic)
  • 427.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Eriksson, Andrea
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Fredman, Margareta
    Kullén Engström, Agneta
    Lean i hälso- och sjukvården2013In: Lean i Arbetslivet / [ed] Per Sederblad, Stockholm: Liber, 2013, 1, p. 142-161Chapter in book (Other academic)
  • 428.
    Dellve, Lotta
    et al.
    University of Borås, Sweden.
    Eriksson, Andrea
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Williamsson, Anna
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Strömgren, Marcus
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Andreasson, Jörgen
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics. University of Borås, Sweden.
    Holden, Richard
    Lean implementation approaches at different levels in Swedish hospitals: the importance for working conditions, worker engagement, health and performance2014Conference paper (Refereed)
    Abstract [en]

    Background

    Swedish healthcare organizations are investing heavily in internal reforms. Lean has been frequently used as an overall concept to improve care processes and decrease costs. Some evidence shows positive results, especially if work environment issues are considered in parallel with other desired outcomes. However, there are considerable difficulties in evaluating lean as a concept since its application and interpretation seem to vary widely. Further, like for other management concepts, lean outcomes crucially depend on the implementation process.

    Aim

    This program investigates implementations of lean and lean-like developments of processes of care, and how these affect the working conditions, health, and performance of healthcare employees. We also investigated organizational factors and conditions that mediated specific outcomes.

    Method

    Mixed method design: questionnaire to employees (n=880) and managers (n=320), qualitative interviews (n=55) and observations with follow up during three years. Five hospitals were selected, and within them five units that were connected by their flow of acute care patients, i.e. the emergency unit, the medical and surgical emergency ward (or ICU at small hospital) as well as one medical and one surgical ward. Initially we used qualitative-driven analyses and thereafter quantitative-driven mixed method analysis.

    Results

    The implementation strategies varied between the hospitals and between the strategic and operative levels. Strategic managers also used different approaches to overcome the gap between strategic and operative levels. Operative managers shared similarities in their stepwise and coaching approaches encouraging participation among employees, but differences regarding how assignments were delegated. Social capital and attitudes among health care profession were of importance for employees’ work engagement and active engagement in development work.

  • 429.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics. Högskolan i Borås, Sweden.
    Fallman, S. L.
    Ahlstrom, L.
    Return to work from long-term sick leave: a six-year prospective study of the importance of adjustment latitudes at work and home2015In: International Archives of Occupational and Environmental Health, ISSN 0340-0131, E-ISSN 1432-1246, Vol. 89, no 1, p. 171-179Article in journal (Refereed)
    Abstract [en]

    Purpose: The aim was to investigate the long-term importance of adjustment latitude for increased work ability and return to work among female human service workers on long-term sick leave. Methods: A cohort of female human service workers on long-term sick leave (>60 days) was given a questionnaire four times (0, 6, 12, 60 months). Linear mixed models were used for longitudinal analysis of the repeated measurements of work ability and return to work. Results: Having a higher level of adjustment latitude was associated with both increased work ability and return to work. Adjustments related to work pace were strongly associated with increased work ability, as were adjustments to the work place. Having individual opportunities for taking short breaks and a general acceptance of taking short breaks were associated with increased work ability. At home, a higher level of responsibility for household work was related to increased work ability and return to work. Individuals with possibilities for adjustment latitude, especially pace and place at work, and an acceptance of taking breaks had greater increased work ability over time and a greater work ability compared with individuals who did not have such opportunities.Conclusions: This study highlights the importance of opportunities for adjustment latitude at work to increase work ability and return to work among female human service workers who have been on long-term sick leave. The results support push and pull theories for individual decision-making on return to work.

  • 430.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Galvin, Kathleen
    Hull University, UK.
    Crafting life-world led leadership2014Conference paper (Other academic)
  • 431.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Jutengren, Göran
    Högskolan Borås.
    Ahlborg, Gunnar
    Institutet för Stressmedicin.
    Chefsspecifika stressorer och stödresurser: betydelse för hållbart ledarskap bland chefer i vård och omsorg2014In: Chefskapets förutsättningar och konsekvenser: Metoder och resultat från CHEFiOS projektet – slutrapport I / [ed] Annika Härenstam, Göteborg: Institutet för Stressmedicin , 2014Chapter in book (Other academic)
  • 432.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Samuelsson, L.
    Waye, K. P.
    Preschool Children's Experience and Understanding of Their Soundscape2013In: Qualitative Research in Psychology, ISSN 1478-0887, E-ISSN 1478-0895, Vol. 10, no 1, p. 1-13Article in journal (Refereed)
    Abstract [en]

    Noise may be a serious health problem in preschools. This article explores how preschool-aged children experience, understand, and cope with the soundscape at their preschools. Using a qualitative approach, 36 children (4-6 years old) were interviewed in 11 focus groups. The children related their experience of sound to the consequences the sound had for themselves, their understanding of its source, and their bodily and emotional experience of it. Their perceived trustfulness, comprehensibility, sound descriptions, and manageability of given sounds were interpreted in the model as an expression of uncontrollability. The degree of uncontrollability of sounds accounted for whether children were nondisturbed, disturbed, or distressed by their experience of it. Distressing noise was experienced as both physically and emotionally painful. The children handled such distress by flight, attempting to reduce the hearing sensation, turning to their teachers, and using cognitive strategies. It is important to increase our understanding of how children cope with distressing sounds at preschools.

  • 433.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH). Gothenburg University, Sweden.
    Strömgren, Marcus
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Williamsson, Anna
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Holden, Richard J.
    School of Informatics and Computing, Indiana University, Indianapolis, US.
    Eriksson, Andrea
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Health care clinicians' engagement in organizational redesign of care processes: Health care clinicians' engagement in organizational redesign of care processes2018In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126, Vol. 68, p. 249-257Article in journal (Refereed)
    Abstract [en]

    The Swedish health care system is reorienting towards horizontal organization for care processes. A main challenge is to engage health care clinicians in the process. The aim of this study was to assess engagement (i.e. attitudes and beliefs, the cognitive state and clinical engagement behaviour) among health care clinicians, and to investigate how engagement was related to work resources and demands during organizational redesign. A cohort study was conducted, using a questionnaire distributed to clinicians at five hospitals working with care process improvement approaches, two of them having implemented Lean production. The results show that kinds of engagement are interlinked and contribute to clinical engagement behaviour in quality of care and patient safety. Increased work resources have importance for engagements in organizational improvements, especially in top-down implementations. An extended work engagement model during organizational improvements in health care was supported. The model contributes to knowledge about how and when clinicians are mobilized to engage in organizational changes.

  • 434.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Williamsson, Anna
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Eriksson, Andrea
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Health care professionals’ motivation, engagement and collaboration in organizational developments of processes of care2012Conference paper (Other academic)
  • 435.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Williamsson, Anna
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Strömgren, Marcus
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Holden, Richard
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Eriksson, Andrea
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Lean implementation at different levels in Swedish hospitals: the importance for working conditions and stress2015In: International Journal of Human Factors and Ergonomics, ISSN 2045-7812, Vol. 3, no 3-4, p. 235-253Article in journal (Refereed)
    Abstract [en]

    Healthcare organisations in Sweden are reorienting toward horizontal organisation around care processes. This paper's aim was to investigate how implementation approaches for improvements of care processes in line with lean production (LP), at hospital strategic and operative levels, are associated with working conditions and stress-related health among the employees. Five hospitals working with improvements to care processes were studied using questionnaires to employees (n = 1,303) and interviews at strategic and operative levels at baseline and follow-up. The process redesign implementation strategies varied between the strategic and operative levels. There were associations between a higher degree of LP at operative level and increased work resources and decreased work demands. Physical, cognitive and mental stress-related symptoms were only weakly associated with strategic or operative LP initiatives. There was evidence of more beneficial or improved working conditions in relation to higher degree of LP at operative levels.

  • 436.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Wramsten Wilmar, Maria
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Jacobsson, Christian
    Göteborgs Universitet.
    Ahlborg, Gunnar
    Göteborgs Universitet.
    Ledarskap i vården: Att möta media och undvika personfokuserade drev2014Report (Other academic)
    Abstract [sv]

    Mote med media ar alltmer vanligt for chefer i varden och en viktig del av arbetet. Motet med media har idag ocksa fatt betydelse for chefens psykosociala arbetsmiljo och hallbarhet da personfokuserat, negativt och kritiskt fokus i media kan vara utmanande och fa vidare konsekvenser. Medvetenhet om mojligheter och risker vid mediakommunikation samt proaktiva forberedelser hos individen och organisationen kan ha avgorande betydelse for att understodja mer saklig och korrekt beskrivning i media samt for att undvika personfokuserade drev. Genom en utvecklad forstaelse och handlingsberedskap samt stod i ledningsgrupper till den som moter media kan negativa konsekvenser minska.

  • 437.
    Dellve, Lotta
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Wramsten Wilmar, Maria
    KTH, School of Technology and Health (STH).
    Jacobsson, Christian
    Ahlborg, Gunnar jr
    Managers approaches towards media during organizational development processes2012Conference paper (Refereed)
  • 438.
    Di Sopra, Lorenzo
    KTH, School of Technology and Health (STH).
    Geometric Misalignment Calibration and Detector Lag Effect Artifact Correction in a Cone-Beam Flat Panel micro-CT System for Small Animal Imaging2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The cone-beam flat panel micro-CT is a high definition imaging system. It acquires projections of an object or animal to reconstruct a 3D image of its internal structure. The device is basically composed by a radiation tube and a detector panel, which are fixed to a gantry that rotates all around the test subject. The micro-CT system is affected by several imperfections and problems, that might lead to serious artifacts that deteriorate the quality of the reconstructed image. In particular, two issues have been discussed in the present work: the source-panel geometric misalignment and the detector lag effect. The first problem concerns the consequences of systems where the different elements are not perfectly aligned to each other. The second issue regards the residual signal, left in the detector's sensor after a projection acquisition, which affects the following frames with ghost images. Both these arguments have been investigated to describe their characteristics and behaviour in a typical acquisition protocol. Then two correction methods have been presented and tested on a real micro-CT device to verify their effectiveness in the artifacts compensation. In the end, a comparison between images before and after the corrections is provided and future prospects are discussed.

  • 439.
    Dilén, Erik
    et al.
    KTH, School of Technology and Health (STH), Data- och elektroteknik.
    Lundmark, Emil
    KTH, School of Technology and Health (STH), Data- och elektroteknik.
    En utvärdering av Windows 8 Store applikationer som plattform för VOD-tjänster2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As an effect of Video On Demand (VOD)-usage growing fast June, as a software provider for the television industry, wants to acquire skills and evaluate Windows 8 applications as a platform for VOD services. June already delivers a web-based solution for VOD and now wants a comparison and evaluation of particular knowledge required, time, complexity, data caching, advantages and disadvantages of a Windows 8 application set against this web solution.

    The objectives of the thesis can be divided into three parts: one in which complexity and work effort in Windows 8 application development is evaluated, one in which the tools required to develop a VOD application is evaluated and finally implementing a Windows 8 application for VOD.

    A Windows 8 application was developed and the selected solution methods were documented. Documentation and knowledge acquired during the development phase was then used as a basis for the analysis and evaluation objectives. The result is a Windows 8 application meeting the objectives set for the development part followed by an analysis and evaluation answering the given issues.

    Matters that are central through the report are Microsoft, WinRT, VOD, PlayReady, Smooth Streaming, Windows 8 application Development, data caching and interface development in Windows 8.

  • 440.
    Ding, Christofer
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering.
    Evaluation of Recommender System2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Recommender System (RS) has become one of the most important component for many companies, such as YouTube and Amazon. A recommender system consists of a series of algorithms which predict and recommend products to users. This report covers the selection of many open source recommender system projects, and movie predictions are made using the selected recommender system. Based on the predictions, a comparison was made between precision and an improved precision algorithm.

    The selected RS uses singular value decomposition in the field of collaborative filtering. Based on the recommendation results produced by the RS, the comparison between precision and the improved precision algorithms showed that the result of improved precision is slightly higher than precision in different cutoff values and different dimensions of eigenvalues.

  • 441.
    Dizdarevic, Sven
    et al.
    KTH, School of Technology and Health (STH).
    Thunholm, Malin
    KTH, School of Technology and Health (STH).
    Signalförändring i automatisk urinmätare: - en ingående studie om dess orsaker2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The following report discusses what substances affect the conditions for the formation of biofim in Observe Medicals digital urine measurement system Sippi, and therefore interfere with the measuring signal. Suggestions on how to possibly avoid volume measurement errors are given. The report accounts for five different solutions used during laboratory experiments: albumin mixed with water, free hemoglobin mixed with water, albumin mixed with urine, free hemoglobin mixed with urine, and lastly only urine. During the volume measurements, fluid was pumped from a container to the measurement chamber in the Sippi set. Each measurement was performed twice, with and without a silicon capsule in the chamber. The laboration results showed that albumin develop a complete biofilm after a few hours. Free hemoglobin entailed a varying degree of biofilm development in Sippi, depending on the amount of blood in the solution. The silicon capsule counteracts the effect of albumin to a higher degree than free hemoglobin. Furthermore, urine with low pH (6,0) did not give rise to biofilm to the same extent as urine with high pH (7,0). The report discusses about the fact that low value of pH in urine negatively affects the conditions for formation of biofilm, and may be used to further develop the product in the future. The report concludes that both albumin and free hemoglobin contribute to construction of biofilm in Sippi, and therefore interfere with the signal.

  • 442.
    Dizon, Lucas
    et al.
    KTH, School of Technology and Health (STH).
    Johansson, Martin
    KTH, School of Technology and Health (STH).
    Atrial Fibrillation Detection Algorithm Evaluation and Implementation in Java2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Atrial fibrillation is a common heart arrhythmia which is characterized by a missing or irregular contraction of the atria. The disease is a risk factor for other more serious diseases and the total medical costs in society are extensive. Therefore it would be beneficial to improve and optimize the prevention and detection of the disease.

     

    Pulse palpation and heart auscultation can facilitate the detection of atrial fibrillation clinically, but the diagnosis is generally confirmed by an ECG examination. Today there are several algorithms that detect atrial fibrillation by analysing an ECG. A common method is to study the heart rate variability (HRV) and by different types of statistical calculations find episodes of atrial fibrillation which deviates from normal sinus rhythm.

     

    Two algorithms for detection of atrial fibrillation have been evaluated in Matlab. One is based on the coefficient of variation and the other uses a logistic regression model. Training and testing of the algorithms were done with data from the Physionet MIT database. Several steps of signal processing were used to remove different types of noise and artefacts before the data could be used.

     

    When testing the algorithms, the CV algorithm performed with a sensitivity of 91,38%, a specificity of 93,93% and accuracy of 92,92%, and the results of the logistic regression algorithm was a sensitivity of 97,23%, specificity of 93,79% and accuracy of 95,39%. The logistic regression algorithm performed better and was chosen for implementation in Java, where it achieved a sensitivity of 97,31%, specificity of 93,47% and accuracy of 95,25%.

  • 443. Dolenc Grošelj, L
    et al.
    Morrisson, SA
    Mirnik, D
    Korsic, S
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology. KTH, School of Technology and Health (STH), Centres, Swedish Aerospace Physiology Centre, SAPC.
    Mekjavic, IB
    PlanHab: Periodic breathing during hypoxic bedrest2015Conference paper (Refereed)
  • 444. Donker, D. W.
    et al.
    Meuwese, C. L.
    Braithwaite, S. A.
    Broomé, Michael
    KTH, School of Technology and Health (STH). Karolinska Institute, Stockholm, Sweden.
    van der Heijden, J. J.
    Hermens, J. A.
    Platenkamp, M.
    de Jong, M.
    Janssen, J. G. D.
    Balík, M.
    Bělohlávek, J.
    Echocardiography in extracorporeal life support: A key player in procedural guidance, tailoring and monitoring2018In: Perfusion, ISSN 0267-6591, E-ISSN 1477-111X, Vol. 33, no 1_suppl, p. 31-41Article in journal (Refereed)
    Abstract [en]

    Extracorporeal life support (ECLS) is a mainstay of current practice in severe respiratory, circulatory or cardiac failure refractory to conventional management. The inherent complexity of different ECLS modes and their influence on the native pulmonary and cardiovascular system require patient-specific tailoring to optimize outcome. Echocardiography plays a key role throughout the ECLS care, including patient selection, adequate placement of cannulas, monitoring, weaning and follow-up after decannulation. For this purpose, echocardiographers require specific ECLS-related knowledge and skills, which are outlined here.

  • 445. Donofrio, P.
    et al.
    Dahlgren, Anna
    KTH, School of Technology and Health (STH), Patientsäkerhet.
    Barnett, M.
    Lutzhoft, M.
    Kircher, A.
    Gillberg, M.
    Kecklund, G.
    Akerstedt, T.
    The effects of a 6 h on/6 h off maritime watch system on sleep2012In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 21, p. 268-269Article in journal (Other academic)
  • 446.
    Duvheim Bruce, Adam
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering.
    Indreeide, Ole Martn
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering.
    Beräkning av återmatad bromsenergi på Malmbanan2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Energy is a limited recourse and the use of energy has to be as effective as possible to avoid harmful effects on the environment and to cut spending. Reusing the energy the ore train uses to climb the mountains of northern Sweden through regenerative breaking leads to a more effective use of energy. Calculation of energy uses the trains’ stored energy and the losses during its journey along Malmbanan. This results in a total power save of 20 % for single track and between 20 % and 21 % for double track. Traffic on double track can increase but the relationship between regenerated and consumed energy will be the same. Regenerating energy on the railway reduces today’s negative impact on the environment and leads to savings in energy cost for the company.

  • 447.
    Dybäck, Matilda
    et al.
    KTH, School of Technology and Health (STH).
    Nilsson Hall, Rebecka
    KTH, School of Technology and Health (STH).
    Kartläggning av Sveriges landstings användning av telemedicin2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Sweden's aging population makes the need for a viable health care urgent and telemedicine can be a solution to enable older people to receive or give themselves care in their homes. Furthermore, implementation of telemedicine has the potential to realise profits in society by increasing the accessibility of health care and minimizing travel costs. Sweden’s low population density and geographical configuration makes the advantages of telemedicine even more appealing.

     

    To illustrate the differences between the county councils’ use of telemedicine and thus increasing the possibility for coordinated care between them, the authors have on behalf of the Innovation Centre at the Karolinska University hospital mapped the amount of telemedicine technologies that are available in the Swedish county councils’ today. To collect information an electronic survey and video or telephone interviews were used. This report answers the question of how the use of telemedicine differ between Sweden's county councils in terms of techniques used, how well implemented the technologies are and to what extent the guidelines for development, implementation and use of telemedicine is available. The report also investigated whether the county councils geographic characteristics, in terms of population density and the number of hospitals and health centers, influenced the development of telemedicine.

     

    Of the 21 regional councils information has been collected from 10 counties in seven weeks and the results that were collocated indicated that there are major differences between the county councils' use of telemedicine. It is clear that the northern region and especially Västerbotten and Norrbotten County Council have come a long way in implementing telemedicine technology.

     

    When the results of the electronic survey and interviews were compared with the county councils’ geographical features no correlation could be detected between population density and the use of telemedicine. This can be a result of the low number of participating counties and that we have not examined all departments in health care. The county councils which have university hospitals use multidisciplinary rounds more so than others. In summary, the Swedish county councils are at different stages in the implementation of telemedicine due to several external and internal factors that makes it possible for counties to benefit a lot from collaboration and sharing each other's knowledge.

  • 448.
    Dybäck, Matilda
    et al.
    KTH, School of Technology and Health (STH).
    Wallgren, Johanna
    KTH, School of Technology and Health (STH).
    Pupil dilation as an indicator for auditory signal detection: Towards an objective hearing test based on eye tracking2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    An early detection of hearing loss in children is important for the child's speech and language development. For children between 3-6 months, a reliable method to measure hearing and determine hearing thresholds is missing. A hearing test based on the pupillary response to auditory signal detection as measured by eye tracking is based on an automatic physiological response. This hearing test could be used instead of the objective hearing tests used today. The presence of pupillary response has been shown in response to speech, but it is unstudied in response to sinus tones. The objective of this thesis was to study whether there is a consistent pupillary response to different sinus tone frequencies commonly used in hearing tests and if yes, to determine reliably the time window of this response.

    Four different tests were done. The adult pupillary response in regard to sinus tone stimuli with four frequency levels (500 Hz, 1000 Hz, 2000 Hz and 4000 Hz), and four loudness levels (silence, 30 dB, 50 dB and 70 dB) was tested (N=20, 15 females, 5 males). Different brightness levels and distractions on the eye tracking screen were investigated in three substudies (N=5, 4 females, 1 male). Differences between silence and loudness levels within frequency levels were tested for statistical significance.

    A pupillary response in regard to sinus tones occurred consistently between 300 ms and 2000 ms with individual variation, i.e. earlier than for speech sounds. Differences between silence and loudness levels were only statistically significant for 4000 Hz. No statistical difference was shown between different brightness levels or if there were distractions present on the eye tracker screen.

    The conclusion is that pupillary response to pure sinus tones in adults is a possible measure of hearing threshold for at least 4000 Hz. Larger studies are needed to confirm this, and also to more thoroughly investigate the other frequencies. 

  • 449. Dénes, E.
    et al.
    Fenyvesi, A.
    Futó, E.
    Kerék, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Kiss, T.
    Molnár, J.
    Novák, D.
    Soós, C.
    Tölyhi, T.
    VandeVyvre, P.
    Radiation tolerance qualification tests of the final source interface unit for the ALICE experiment for the ALICE collaboration2007In: Proceedings - 12th Workshop on Electronics for LHC and Future Experiments, LECC 2006, CERN , 2007, p. 438-441Conference paper (Refereed)
    Abstract [en]

    The ALICE Detector Data Link (DDL) is a high-speed optical link designed to interface the readout electronics of ALICE sub-detectors to the DAQ computers. The Source Interface Unit (SIU) of the DDL will operate in radiation environment. Previous tests showed that a configuration loss of SRAM-based FPGA devices may happen and the frequency of undetected data errors in the FPGA user memory area is also not acceptable. Therefore, we redesigned the SIU card using another FPGA based on flash technology. In order to detect bit errors in the user memory we added parity check logic to the design. The new SIU has been extensively tested using neutron and proton irradiation to verify its radiation tolerance. In this paper we summarize the design changes, introduce the final design, and the results of the radiation tolerance measurements on the final card.

  • 450. Dénes, E.
    et al.
    Fenyvesi, A.
    Hirn, A.
    Kerék, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Kiss, T.
    Molnár, J.
    Novák, D.
    Soós, C.
    Tölyhi, T.
    Vyvre, P. V.
    Radiation tolerant source interface unit for the ALICE experiment2005In: Proceedings - 11th Workshop on Electronics for LHC and Future Experiments, LECC 2005, CERN , 2005, p. 291-293Conference paper (Refereed)
    Abstract [en]

    The ALICE Detector Data Link (DDL) is a high-speed optical link designed to interface the readout electronics of ALICE sub-detectors to the DAQ computers. The Source Interface Unit (SIU) of the DDL will operate in radiation environment. Tests showed that configuration loss of the Altera APEX II FPGA device used earlier on the DDL SIU card is only marginally acceptable. We developed a new version of the SIU card using Actel ProASIC+ device based on flash memory technology. The new SIU card has been extensively tested using neutron and proton irradiation. In this paper we present the SIU card and describe the results of irradiation measurements.

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