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  • 1. Andersson, Per
    et al.
    Björkholm, Peter
    Haasl, Sjoerd
    KTH, School of Technology and Health (STH), Centres, Centre for Technology in Medicine and Health, CTMH.
    Johannisson, Pontus
    Johnsson, Christer
    Stigwall, Johan
    Södermalm, Svante
    MEMS-based inertial navigation instrumentation for high-dynamic applications2009In: COMS 2009, 2009Conference paper (Refereed)
  • 2.
    Antoni, Per
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hed, Yvonne
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Nordberg, Axel
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Nyström, Daniel
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malkoch, Michael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Bifunctional Dendrimers: From Robust Synthesis and Accelerated One-Pot Postfunctionalization Strategy to Potential Applications2009In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 48, no 12, p. 2126-2130Article in journal (Refereed)
  • 3.
    Asplund, Maria
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Thaning, Elin
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Lundberg, J.
    Sandberg-Nordqvist, A. C.
    Kostyszyn, B.
    Inganas, O.
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
    Toxicity evaluation of PEDOT/biomolecular composites intended for neural communication electrodes2009Article in journal (Refereed)
    Abstract [en]

    Electrodes coated with the conducting polymer poly(3,4-ethylene dioxythiophene) (PEDOT) possess attractive electrochemical properties for stimulation or recording in the nervous system. Biomolecules, added as counter ions in electropolymerization, could further improve the biomaterial properties, eliminating the need for surfactant counter ions in the process. Such PEDOT/biomolecular composites, using heparin or hyaluronic acid, have previously been investigated electrochemically. In the present study, their biocompatibility is evaluated. An agarose overlay assay using L929 fibroblasts, and elution and direct contact tests on human neuroblastoma SH-SY5Y cells are applied to investigate cytotoxicity in vitro. PEDOT: heparin was further evaluated in vivo through polymer-coated implants in rodent cortex. No cytotoxic response was seen to any of the PEDOT materials tested. The examination of cortical tissue exposed to polymer-coated implants showed extensive glial scarring irrespective of implant material (Pt:polymer or Pt). However, quantification of immunological response, through distance measurements from implant site to closest neuron and counting of ED1+ cell density around implant, was comparable to those of platinum controls. These results indicate that PEDOT: heparin surfaces were non-cytotoxic and show no marked difference in immunological response in cortical tissue compared to pure platinum controls.

  • 4.
    Ayas, Ebru
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    Ishihara, Shigekazu
    An Analysis on Affective Design of Servicescapes2009In: Proceedings of 12 th QMOD and Toulon-Verona Conference on Quality and Service Sciences, 2009Conference paper (Refereed)
  • 5.
    Ayllon, David
    et al.
    Department of Signal Theory and Communications.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Gil-Pita, Roberto
    Department of Signal Theory and Communications.
    Cole equation and parameter estimation from electrical bioimpedance spectroscopy measurements: A comparative study2009In: EMBC: 2009 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-20, Buenos Aires: IEEE Engineering in Medicine and Biology , 2009, p. 3779-3782Conference paper (Refereed)
    Abstract [en]

    Since there are several applications of Electrical Bioimpedance (EBI) that use the Cole parameters as base of the analysis, to fit EBI measured data onto the Cole equation is a very common practice within Multifrequency-EBI and spectroscopy. The aim of this paper is to compare different fitting methods for EBI data in order to evaluate their suitability to fit the Cole equation and estimate the Cole parameters. Three of the studied fittings are based on the use of Non-Linear Least Squares on the Cole model, one using the real part only, a second using the imaginary part and the third using the complex impedance. Furthermore, a novel fitting method done on the impedance plane, without using any frequency information has been implemented and included in the comparison. Results show that the four methods perform relatively well but the best fitting in terms of standard error of estimate is the fitting obtained from the resistance only. The results support the possibility of measuring only the resistive part of the bioimpedance to accurately fit Cole equation and estimate the Cole parameters, with entailed advantages.

  • 6. Bak, Zoltan
    et al.
    Sjöberg, Folke
    Hälsouniversitetet, Linköping University.
    Eriksson, Olle
    Steinvall, Ingrid
    Janerot-Sjoberg, Birgitta
    KTH, School of Technology and Health (STH), Medical Engineering.
    Hemodynamic changes during resuscitation after burns using the Parkland formula2009In: Journal of Trauma, ISSN 0022-5282, E-ISSN 1529-8809, Vol. 66, no 2, p. 329-336Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The Parkland formula (2-4 mL/kg/burned area of total body surface area %) with urine output and mean arterial pressure (MAP) as endpoints for the fluid resuscitation in burns is recommended all over the world. There has recently been a discussion on whether central circulatory endpoints should be used instead, and also whether volumes of fluid should be larger. Despite this, there are few central hemodynamic data available in the literature about the results when the formula is used correctly.

    METHODS: Ten burned patients, admitted to our unit early, and with a burned area of >20% of total body surface area were investigated at 12, 24, and 36 hours after injury. Using transesophageal echocardiography, pulmonary artery catheterization, and transpulmonary thermodilution to monitor them, we evaluated the cardiovascular coupling when urinary output and MAP were used as endpoints.

    RESULTS: Oxygen transport variables, heart rate, MAP, and left ventricular fractional area, did not change significantly during fluid resuscitation. Left ventricular end-systolic and end-diastolic area and global end-diastolic volume index increased from subnormal values at 12 hours to normal ranges at 24 hours after the burn. Extravascular lung water: intrathoracal blood volume ratio was increased 12 hours after the burn.

    CONCLUSIONS: Preload variables, global systolic function, and oxygen transport recorded simultaneously by three separate methods showed no need to increase the total fluid volume within 36 hours of a major burn. Early (12 hours) signs of central circulatory hypovolemia, however, support more rapid infusion of fluid at the beginning of treatment.

  • 7.
    Berglund, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Integrated Product Development.
    Sturm, Dennis
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Parida, Vinit
    Luleå University of Technology.
    Embracing Entrepreneurial Behaviour in a Research School2009Conference paper (Refereed)
    Abstract [en]

    The Product Innovation Engineering program (PIEp) has recently established a Research School withthe aim to increase innovation capabilities in Swedish industries and to promote entrepreneurialbehaviour. By following a bottom-up approach PIEp has been able to both embrace and fosterentrepreneurship. As a result, the research school has already been able to change preexisting mindsetsand to encourage PhD students to be more proactive, risk-taking and innovative. Through descriptions of their own experiences and of key cases along the way, the authors illustratethe transformation from the initial idea to the research school as it is today. This paper seeks toprovide insight and draw comparisons with other research schools to further research and assist policymakers interested in founding new research schools.

  • 8.
    Bjällmark, Anna
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Larsson, Matilda
    KTH, School of Technology and Health (STH), Medical Engineering.
    Shahgaldi, Kambiz
    Lind, Britta
    KTH, School of Technology and Health (STH).
    Winter, Reidar
    Brodin, Lars-Ake
    KTH, School of Technology and Health (STH), Medical Engineering.
    Differences in myocardial velocities during supine and upright exercise stress echocardiography in healthy adults2009In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 29, no 3, p. 216-223Article in journal (Refereed)
    Abstract [en]

    Tissue Velocity Imaging (TVI) is a method for quantitative analysis of longitudinal myocardial velocities, which can be used during exercise and pharmacological stress echocardiography. It is of interest to evaluate cardiac response to different types of stress tests and the differences between upright and supine bicycle exercise tests have not been fully investigated. Therefore, the aim of this study was to compare cardiac response during supine and upright exercise stress tests. Twenty young healthy individuals underwent supine and upright stress test. The initial workload was set to 30 W and was increased every minute by a further 30 W until physical exhaustion. Tissue Doppler data from the left ventricle were acquired at the end of every workload level using a GE Vivid7 Dimension system (> 200 frames s(-1)). In the off-line processing, isovolumic contraction velocity (IVCV), peak systolic velocity (PSV), isovolumic relaxation velocity (IVRV), peak early diastolic velocity (E') and peak late diastolic velocity (A') were identified at every workload level. No significant difference between the tests was found in PSV. On the contrary, E' was shown to be significantly higher (P < 0.001) during supine exercise than during upright exercise and IVRV was significantly lower (P < 0.001) during supine exercise compared to upright exercise. Upright and supine exercise stress echocardiography give a comparable increase in measured systolic velocities and significant differences in early diastolic velocities.

  • 9.
    Bohgard, Mats
    et al.
    Lunds universitet.
    Karlsson, StigLuleå tekniska universitet.Lovén, EvaLinköpings universitet.Mikaelsson, Lars-ÅkeMittuniversitetet.Mårtensson, LenaKTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial Work Science (closed 20130101).Osvalder, Anna-LisaChalmers tekniska högskola.Rose, Linda M.KTH, School of Technology and Health (STH), Ergonomics (Closed 20130701).Ulfvengren, PernillaKTH, School of Industrial Engineering and Management (ITM).
    Work and technology on human terms2009Collection (editor) (Refereed)
  • 10.
    Brännmark, Mikael
    KTH, School of Technology and Health (STH), Ergonomics.
    Ökad delaktighet i programutvärdering: En metodik för ökad resultatspridning?2009In: HSS2009: Vi bygger morgondagens samhälle, Luleå, 2009, p. 1-26Conference paper (Refereed)
  • 11. Börsbo, Björn
    et al.
    Peolsson, Michael
    KTH, School of Technology and Health (STH), Centres, Centre for Technology in Medicine and Health, CTMH.
    Gerdle, Björn
    The complex interplay between pain intensity, depression, anxiety and catastrophising with respect to quality of life and disability2009In: Disability and Rehabilitation, ISSN 0963-8288, E-ISSN 1464-5165, Vol. 31, no 19, p. 1605-1613Article in journal (Refereed)
    Abstract [en]

    Purpose. To identify subgroups of patients with chronic pain based on the occurrence of depression, anxiety and catastrophising and the duration of pain and pain intensity. In addition to this, the relationship between the subgroups with respect to background variables, diagnosis, pain-related disability and perceived quality of life are investigated. Methods. This study used 433 patients with chronic pain including 47 patients with spinal cord injury-related pain, 150 with chronic whiplash associated disorders and 236 with fibromyalgia. The participants answered a postal questionnaire that provided background data, pain intensity and duration and psychological and health-related items. Results. On the basis of depression, anxiety, catastrophising, pain intensity and duration, we identified subgroups of patients with chronic pain that differed with respect to perceived quality of life, disability and diagnosis. The psychological factors, especially depression, significantly influenced perceived quality of life and disability. Pain intensity and duration play a minor role with respect to quality of life, although pain intensity is associated to perceived disability. Conclusions. The results of this study highlight the importance of not looking at patients with chronic pain as a homogenous entity. A detailed assessment, including psychological factors with emphasis on depressive symptoms, might be essential for planning and carrying through treatment and rehabilitation.

  • 12. 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.
    Hematological responses to two different intermittent hypoxic training regimens2009Conference paper (Refereed)
    Abstract [en]

    "Hypoxic training has been reported to enhance athletes’ altitude and sea-level performance by augmenting oxygen carrying capacity of the blood, as a consequence of increases in hematocrit and hemoglobin concentrations. However the effect of intermittent hypoxic training on hematological responses remains unresolved."

    This study investigated the effect of two intermittent hypoxic training regimens on the response of hematological indices. Healthy male Ss (N = 27) were equally assigned to a control group, a live low-train high (LL-TH) group, or a intermittent hypoxic exposure group. Ss performed a one-hour submaximal endurance exercise on a cycle ergometer, five days per week for four weeks, at an intensity corresponding to 50% of normoxic peak power output for the control and intermittent hypoxic exposure groups, and to 50% of hypoxic peak power output for the LL-TH group. Thus, all groups trained at the same relative work rate. The absolute work rate during training was 18-20 W lower for the LL-TH group compared to the other two groups. All groups lived at an altitude of ~300 m above sea level. The control and intermittent hypoxic exposure groups also trained at this altitude, whereas the LL-TH group trained in a hypoxic chamber, breathing a hypoxic mixture (FIO2=12%). In addition to the daily exercise training, the intermittent hypoxic exposure group also inspired a hypoxic gas mixture at rest, and prior to the cycle ergometry. The intermittent hypoxic training comprised breathing a hypoxic mixture during seven phases. Each phase consisted of five minutes of breathing a hypoxic mixture, followed by three minutes of breathing a normoxic gas mixture. Prior to, during, at the end, and 10 days after the training period, blood samples were taken from all Ss in order to measure hemoglobin, hematocrit, erythrocytes, ferritin, and transferrin concentrations.

    No significant differences were observed between groups in any measured hematological variables. Similarly, no significant differences were found within groups at the different testing periods.

    Implication. Although it has been reported that both LL-TH and intermittent hypoxic exposure protocols provide hematological benefits, that was not confirmed by this study. The tested protocols did not induce any changes in the measured hematological variables; therefore no improvements of the oxygen carrying capacity of the blood should be expected following this type of hypoxic training.

  • 13.
    Eklund, Jörgen
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Brännmark, Mikael
    KTH, School of Technology and Health (STH), Ergonomics.
    Sustainable development for ergonomics improvement projects2009Conference paper (Refereed)
  • 14.
    Elmlund, Dominika
    et al.
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Elmlund, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    High-resolution single-particle orientation refinement based on spectrally self-adapting common lines2009In: Journal of Structural Biology, ISSN 1047-8477, E-ISSN 1095-8657, Vol. 167, no 1, p. 83-94Article in journal (Refereed)
    Abstract [en]

    Three-dimensional (3D) structure determination from electron microscopic images of single molecules can be difficult for particles with low or no internal symmetry, and for images with low signal-to-noise ratio (SNR), due to the existence of false maxima in the scoring function used for orientation search. In attempt to improve robustness of orientation parameter refinement towards noise and poor starting reconstruction quality, we have developed a method for common lines-based orientation search in Fourier space. The Fourier-space formulation enables inclusion of resolution (spatial frequency of the low-pass limit) as a variable that is adjusted in a particle-dependent, self-adaptive manner. The method allows for the underlying 3D structure to be estimated to high resolution, and requires only a crude, low-resolution reconstruction as starting-point for refinement. Benchmarking of the method is performed on experimental and synthetic data.

  • 15. Elmlund, Hans
    et al.
    Baraznenok, Vera
    Linder, Tomas
    Szilagyi, Zsolt
    Rofougaran, Reza
    Hofer, Anders
    Hebert, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Lindahl, Martin Joakim
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Gustafsson, Claes M.
    Cryo-EM Reveals Promoter DNA Binding and Conformational Flexibility of the General Transcription Factor TFIID2009In: Structure, ISSN 0969-2126, E-ISSN 1878-4186, Vol. 17, no 11, p. 1442-1452Article in journal (Refereed)
    Abstract [en]

    The general transcription factor IID (TFIID) is required for initiation of RNA polymerase II-dependent transcription at many eukaryotic promoters. TFIID comprises the TATA-binding protein (TBP) and several conserved TBP-associated factors (TAFs). Recognition of the core promoter by TFIID assists assembly of the preinitiation complex. Using cryo-electron microscopy in combination with methods for ab initio single-particle reconstruction and heterogeneity analysis, we have produced density maps of two conformational states of Schizosaccharomyces pombe TFIID, containing and lacking TBP. We report that TBP-binding is coupled to a massive histone-fold domain rearrangement. Moreover, docking of the TBP-TAF1(N-terminus) atomic structure to the THID map and reconstruction of a TAF-promoter DNA complex helps to account for TAF-dependent regulation of promoter-TBP and promoter-TAF interactions.

  • 16. Franchoo, S.
    et al.
    Achouri, N. L.
    Algora, A.
    Al-Khatib, A.
    Angelique, J. C.
    Azaiez, F.
    Kerek, Andras
    KTH, School of Technology and Health (STH), Medical Engineering.
    Yamamoto, A.
    et al.,
    RECENT RESULTS FROM GANIL2009In: Acta Physica Polonica B, ISSN 0587-4254, E-ISSN 1509-5770, Vol. 40, no 3, p. 419-425Article in journal (Refereed)
    Abstract [en]

    The shell structure of the nucleus implies the existence of magic numbers. Since several years many indications have been accumulated, theoretically as well as through experiments at various laboratories around the world, that if one moves away from stability, the location of the magic numbers shifts as an inescapable consequence of the evolving nature of the nuclear force itself. In this respect, it is the balance between the tensor and spin-orbit components that seems particularly instrumental. Illustrative examples from recent experiments at Ganil, at the neutron-rich and proton-rich side of the nuclear chart for N or Z equal 20 or 28, will be presented here.

  • 17. Frykberg, Gunilla E.
    et al.
    Aberg, Anna Cristina
    Halvorsen, Kjartan
    KTH, School of Technology and Health (STH), Medical Engineering.
    Borg, Jorgen
    Hirschfeld, Helga
    Temporal Coordination of the Sit-to-Walk Task in Subjects With Stroke and in Controls2009In: Archives of Physical Medicine and Rehabilitation, ISSN 0003-9993, E-ISSN 1532-821X, Vol. 90, no 6, p. 1009-1017Article in journal (Refereed)
    Abstract [en]

    Objectives: To explore events and describe phases for temporal coordination of the sit-to-walk (STW) task, within a semi standardized set up, in subjects with stroke and matched controls. In addition, to assess variability of STW phase duration and to compare the relative duration of STW phases between the 2 groups. Design: Cross-sectional. Setting: Research laboratory. Participants: A convenience sample of persons with hemiparesis (n=10; age 50-67y) more than 6 months after stroke and 10 controls matched for sex, age, height, and body mass index. Interventions: Not applicable. Main Outcome Measures: Relative duration of STW phases, SE of measurement in percentage of the mean, and intraclass correlation coefficients (ICCs). Results: Four STW phases were defined: rise preparation, transition, primary gait initiation, and secondary gait initiation. The Subjects with stroke needed 54% more time to complete the STW task than the controls did. ICCs ranged from .38 to .66 and .22 to .57 in the stroke and control groups, respectively. SEs of measurement in percentage of the mean values were high, particularly in the transition phase: 54.1% (stroke) and 50.4% (controls). The generalized linear model demonstrated that the relative duration of the transition phase was significantly longer in the stroke group. Conclusions: The present results extend existing knowledge by presenting 4 new phases of temporal coordination of STW, within a semistandardized set-up, in persons with stroke and in controls. The high degree of variability regarding relative STW phase duration was probably a result of both the semistandardized Set up and biological variability. The significant difference in the transition phase across the 2 groups requires further study.

  • 18.
    Gennser, Mikael
    et al.
    KTH, School of Technology and Health (STH), Environmental Physiology.
    Blogg, Samantha L.
    Venous Gas Emboli in Goats After Simulated Submarine Escape from 290 msw Breathing Air or Hyperoxic Gas2009In: Aviation, Space and Environmental Medicine, ISSN 0095-6562, E-ISSN 1943-4448, Vol. 80, no 11, p. 927-932Article in journal (Refereed)
    Abstract [en]

    GENNSER M, BLOGG. SL. Venous gas emboli in goats after simulated submarine escape from 290 msw breathing air or hyperoxic gas. Aviat Space Environ Med 2009; 80:927-32. Introduction: Escape from a disabled submarine has many inherent risks. Including the development of venous gas emboli (VGE) Breathing hyperoxic gas during rapid ascent from 2500 kPa (240 msw) reduces VGE, we Investigated whether it would also be beneficial during all escape from 3000 kPa (290 msw), thought to be at the limit of escape from a sunk sub Methods: Adult castrated male or female goats (45-85 kg, N = 35) Underwent dry chamber compression to 3000 kPa in 28 s, then decompressed at a rate of 2 75 m . s(-1) while breathing either air or hyperoxic gas (60/40%. O-2/N-2) Postsurfacing, precordial Doppler measurements were made using the Kisman Masurel (KM) scoring system, the animals were observed for signs of decompression illness (DCI) and/or oxygen toxicity Results: Six animals in the air group (N = 19) and two in the hyperoxic group (N = 10) suffered from severe I)pulmonary barotrauma on surfacing and were euthanized No cases of DO arose later than 5 min postsurfacing. Oxygen toxicity was not observed Although initial bobble Scores (median KM score 4) were the same in both groups, the time taken for the median KM score to reach 3 or less was significantly faster in the hyperoxic group (20 min vs 120 min) Disappearance of VGE was faster in the hyperoxic group Conclusion: Breathing hyperoxic gas during escape from 3000 kPa reduces the overall time. With circulating VGE and, despite exposure to a maximum inspired partial pressure, of oxygen of 1 8 MPa, symptoms of oxygen toxicity were not observed

  • 19. Govind, Satish C.
    et al.
    Gopal, Aasha S.
    Netyo, Anita
    Nowak, Jacek
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Patrianakos, Alexandros
    Ramesh, S. S.
    Saha, Samir
    Quantification of low-dose dobutamine stress using speckle tracking echocardiography in coronary artery disease2009In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 10, no 5, p. 607-612Article in journal (Refereed)
    Abstract [en]

    Aims We sought to evaluate the utility of speckle tracking echocardiography (STE) for detecting left ventricular (LV) mechanical abnormalities during low-dose (20 mu g) dobutamine stress (DSE). Methods and results Twenty-nine patients (56 +/- 12 years) with a history of recent acute coronary events (ACE) underwent STE-DSE. Left ventricular images, sampled at frame rates 70-100 Hz, were analysed off-line (Echopac BT 6.0.0). Velocity, strain, and rotational imaging were performed. Twenty patients had LV ejection fraction (EF) >40% (Group 1) whereas nine patients had LVEF <40% (Group 2). Average heart and frame rates were identical during DSE in the two groups (P = ns). Global circumferential strain (%) was significantly lower in Group 2 compared with Group 1 (10.65 +/- 5.30 vs. 16.82 +/- 6.61; P < 0.05) at rest and during peak stress (14.72 +/- 6.51 vs. 21.13 +/- 7.2; P < 0.05). The global peak rotation rate (degree/s) was, however, higher at rest in Group 2 (70 +/- 97 vs. 19 +/- 67; P < 0.05) and 20 mu g stress. Peak systolic velocity increased in three of the four LV walls at 20 mu g ( in Groups 1 and 2). A global rotational rate increased significantly at 20 mu g during systole in both the groups, but was unchanged in Group 2 during diastole. Conclusions Speckle tracking echocardiography dobutamine stress appears to provide comprehensive information on LV mechanical status in the aftermath of ACE. The modality may help risk stratify such patients.

  • 20. Gullstrand, Lennart
    et al.
    Halvorsen, Kjartan
    Tinmark, Fredrik
    Eriksson, Martin
    KTH, School of Technology and Health (STH), Medical Engineering.
    Nilsson, Johnny
    Measurements of vertical displacement in running, a methodological comparison2009In: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, Vol. 30, no 1, p. 71-75Article in journal (Refereed)
    Abstract [en]

    The aim was (1) to evaluate measurements of vertical displacements (V-disp) of a single point on sacrum as an estimate of the whole body centre of mass (CoM) V-disp during treadmill running and (2) to compare three methods for measuring this single point. These methods were based on a position transducer(PT), accelerometers (AMs) and an optoelectronic motion capture system. Criterion method was V-disp of the whole body CoM measured with the motion capture system. Thirteen subjects ran at 10, 12, 14, 16. 18, 20 and 22 km h(-1) with synchronous recordings with the three methods. Four measurements of the (V-disp) were derived: (1) V-disp of CoM calculated from a segment model consisting of 13 segments tracked with 36 reflective markets, (2) V-disp of the sacrum recorded with the PT, (3) V-disp of the sacrum Calculated from the AM, and (4) V-disp of the sacrum calculated as the mid point of two reflective markets (sacrum marker, SM) attached at the level of the sacral bone. The systematic discrepancy between the Measurements of sacrum V-disp and CoM V-disp varied between 0 and 1.5 mm and decreased with increasing running velocity and decreasing step duration. PT and SM measurements showed strong correlation, whereas the AM showed a variability increasing with velocity. The random discrepancy within each Subject was 7 mm for all three methods. In conclusion single-point recordings of the sacrum V-disp may be used to monitor changes in V-disp of CoM during treadmill running.

  • 21.
    Halilovic, Armin
    KTH, School of Technology and Health (STH), Naturvetenskapliga avdelningen.
    On the Existence of the Henstock-Kurzweil-Stieltjes Multilinear Integral2009In: International journal of pure and applied mathematics, ISSN 1311-8080, E-ISSN 1314-3395, ISSN 1311-8080, Vol. 55, no 4, p. 581-594Article in journal (Refereed)
    Abstract [en]

    In this paper we consider the existence of the Henstock-Kurzweil-Stieltjes multilinear integral for the case when the integrands are regulated functions and the integrators semiregulated functions of bounded semivariation.

  • 22.
    Halilovic, Armin
    KTH, School of Technology and Health (STH), Naturvetenskapliga avdelningen.
    Two types of multilinear Stieltjes integrals in the Henstock-Kurzweil sense2009In: Sarajevo Journal of Mathematics, ISSN 1840-0655, E-ISSN 2233-1964, ISSN 1840-0655, Vol. 5(17), no 1, p. 21-39.Article in journal (Refereed)
    Abstract [en]

    We prove the existence of the Henstock-Kurzweil-Stieltjes multilinear integral for the case when the integrands are regulated functions and the integrators semiregulated functions of bounded semivariation.

  • 23.
    Halvorsen, Kjartan
    et al.
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Brechbühl, Simon
    ETH Zurich, Switzerland.
    Minimal set of markers for center of mass estimation in gravitational fall2009In: Proceedings of the ISB XXII Congress, 2009Conference paper (Refereed)
  • 24.
    Halvorsen, Kjartan
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Eriksson, Martin
    KTH, School of Technology and Health (STH), Medical Engineering.
    Gullstrand, Lennart
    Tinmark, Fredrik
    Nilsson, Johnny
    Minimal marker set for center of mass estimation in running2009In: Gait & Posture, ISSN 0966-6362, E-ISSN 1879-2219, Vol. 30, no 4, p. 552-555Article in journal (Refereed)
    Abstract [en]

    The purpose was to study the validity of a recently proposed method [Forsell C, Halvorsen K. A method for determining minimal sets of markers for the estimation of center of mass, linear and angular momentum. journal of Biomechanics 2009;42(3):361-5] for estimating the trajectory of the whole-body center of mass (CoM) in the case of running at: velocities ranging from 10 to 22 km h(-1). The method gives an approximation to the CoM using the position of fewer markers on the body than the standard method of tracking each segment of the body. Fourteen male athletes participated. A standard method for determining the CoM from a model of 13 segments and using the position of 36 markers was used as reference method. Leave-one-out cross-validation revealed errors that decreased with increasing number of markers used in the approximative method. Starting from four markers, the error in absolute position of the CoM decreased from 15 mm to 3 mm in each direction. For the velocity of the CoM the estimation bias was neglectable, and the random error decreased from 0.15 to 0.05 m s(-1). The inter-subject and intra-subject variability in the estimated model parameters increased with increasing number of markers. The method worked well also when applied to running at velocities outside the range of velocities in the data used to determine the model parameters. The results indicate that a model using 10 markers represents a good trade-off between simplicity and accuracy, but users must take into account requirements of their specific applications.

  • 25.
    Hedenstierna, Sofia
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Halldin, Peter
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Siegmund, Gunter
    MEA Forensic Engineers and Scientists Ltd., Richmond, BC, Canada.
    Neck Muscle Load Distribution in Lateral, Frontal, and Rear-end Impacts: A Three-Dimensional Finite Element Analysis2009In: Spine, ISSN 0362-2436, E-ISSN 1528-1159, Vol. 34, no 24, p. 2626-2633Article in journal (Refereed)
    Abstract [en]

    Study Design. A finite element (FE) model of the human neck was used to study the distribution of neck muscle loads during multidirectional impacts. The computed load distributions were compared to experimental electromyography (EMG) recordings.

    Objective. To quantify passive muscle loads in nonactive cervical muscles during impacts of varying direction and energy, using a three-dimensional (3D) continuum FE muscle model.

    Summary of Background Data. Experimental and numerical studies have confirmed the importance of muscles in the impact response of the neck. Although EMG has been used to measure the relative activity levels in neck muscles during impact tests, this technique has not been able to measure all neck muscles and cannot directly quantify the force distribution between the muscles. A numerical model can give additional insight into muscle loading during impact.

    Methods. An FE model with solid element musculature was used to simulate frontal, lateral, and rear-end vehicle impacts at 4 peak accelerations. The peak cross-sectional forces, internal energies, and effective strains were calculated for each muscle and impact configuration. The computed load distribution was compared with experimental EMG data.

    Results. The load distribution in the cervical muscles varied with load direction. Peak sectional forces, internal energies, and strains increased in most muscles with increasing impact acceleration. The dominant muscles identified by the model for each direction were splenius capitis, levator scapulae, and sternocleidomastoid in lateral impacts, splenius capitis, and trapezoid in frontal impacts, and sternocleidomastoid, rectus capitis posterior minor, and hyoids in rear-end impacts. This corresponded with the most active muscles identified by EMG recordings, although within these muscles the distribution of forces and EMG levels were not the same.

    Conclusion. The passive muscle forces, strains, and energies computed using a continuum FE model of the cervical musculature distinguished between impact directions and peak accelerations, and on the basis of prior studies, isolated the most important muscles for each direction.

  • 26. Henje Blom, Eva
    et al.
    Olsson, Erik M G
    Serlachius, Eva
    Ericson, Mats
    KTH, School of Technology and Health (STH), Ergonomics (Closed 20130701).
    Ingvar, Martin
    Heart rate variability is related to self-reported physical activity in a healthy adolescent population2009In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 106, no 6, p. 877-83Article in journal (Refereed)
    Abstract [en]

    This study investigated whether there is a relationship between heart rate variability (HRV) versus lifestyle and risk factors for cardiovascular disease in a population of healthy adolescents. HRV is as an index of tonic autonomic activity and in adults HRV is related to lifestyle and risk factors for cardiovascular disease, but it is not known if this is the case in adolescents. HRV was registered for 4 min in sitting position in 99 healthy adolescents (age range 15 years 11 months-17 years 7 months) and repeated after 6 months. On both occasions there were significant correlations (P < 0.05) between physical activity and HRV, with respective r values: high frequency (HF) 0.26, 0.30; low frequency power (LF) 0.35, 0.29 and the standard deviation of inter-beat intervals (SDNN) 0.28, 0.37. There was no significant interaction between first and second measurements. In contrast, there were no correlations to sleeping patterns, eating habits and smoking. Risk factors for cardiovascular disease [body mass index (BMI = weight (kg)/length in m(2)), systolic blood pressure and p-glucose] did not show any repeatable significant correlations to HRV. Multiple regression models showed that physical activity was a predictor for HF, LF and SDNN in both measurements. In conclusion HF, LF and SDNN were reproducible after 6 months and were related to physical activity on both occasions.

  • 27.
    Ho, Johnson
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Can sulci protect the brain from traumatic injury?2009In: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 42, no 13, p. 2074-2080Article in journal (Refereed)
    Abstract [en]

    The influence of sulci in dynamic finite element simulations of the human head has been investigated. First, a detailed 3D FE model was constructed based on an MRI scan of a human head. A second model with a smoothed brain surface was created based on the same MRI scan as the first FE model. These models were validated against experimental data to confirm their human-like dynamic responses during impact. The validated FE models were subjected to several acceleration impulses and the maximum principle strain and strain rate in the brain were analyzed. The results suggested that the inclusion of sulci should be considered for future FE head models as it alters the strain and strain distribution in an FE model.

  • 28.
    Ho, Johnson
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Automatic generation and validation of patient-specific finite element head models suitable for crashworthiness analysis2009In: International Journal of Crashworthiness, ISSN 1358-8265, E-ISSN 1754-2111, Vol. 14, no 6, p. 555-563Article in journal (Refereed)
    Abstract [en]

    A method to automatically generate finite element (FE) head models is presented in this paper. Individual variation in geometry of the head should be taken into consideration in future injury-prediction research. To avoid inter- and intra-operator variation due to manual segmentation, a robust and accurate algorithm is suggested. The current approach utilises expectation maximisation classification and skull stripping. The whole process from geometry extraction to model generation is converted into an automatic scheme. The models that are generated from the proposed method are validated in terms of segmentation accuracy, element quality and injury-prediction ability. The segmentations of the white matter and grey matter are about 90% accurate and the models have good element quality, with 94% of the elements having a Jacobian above 0.5. Using the experimental data from post-mortem human subject heads, nodal displacements were compared with the data collected from the simulations with the FE head models. The results are promising, indicating that the proposed method is good enough to generate patient-specific model for brain injury prediction. Further improvement can be made in terms of geometry accuracy and element quality.

  • 29. Kasai, Nahoko
    et al.
    Shimada, Akiyoshi
    Nyberg, Tobias A.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Torimitsu, Keiichi
    An Electrochemical Sensor Array and Its Application to Real-Time Brain Slice Imaging2009In: Electronics and Communications in Japan, ISSN 1942-9533, Vol. 92, no 9, p. 217-221Article in journal (Refereed)
    Abstract [en]

    An electrochemical sensing system using a planar microelectrode array has been developed for monitoring biological molecules with relatively high spatial and temporal resolution. This allows noninvasive real-time imaging of biological molecules released from tissue. In this study, we establish a multichannel hydrogen peroxide (H2O2) sensing system to monitor the real-time H2O2 distribution in tissue using a planar sensor array. H2O2 is known to be associated with the pathology of neurological diseases because it is a by-product of degenerative reactions involving reactive oxygen species, which are a major cause of oxidative stress in mammalian cells. The sensor array is based on a 64-channel ITO electrode array composed of 50 x 50 mu m electrodes modified with an enzyme (horseradish peroxidase) and an electron transfer mediator. We place a cultured rat hippocampal slice on the array and measure the current at each sensor using a multipotentiostat. When we introduce bicuculline into the solution as a stimulant in the presence of a catalase inhibitor, we can observe a distinct increase in the H2O2 concentration. This real-time H2O2 distribution monitoring system is a powerful tool with which to explore the neuronal cell death mechanism in biological systems.

  • 30.
    Larsson, Matilda
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Bjällmark, Anna
    KTH, School of Technology and Health (STH), Medical Engineering.
    Lind, Britta
    KTH, School of Technology and Health (STH), Medical Engineering.
    Balzano, Rita
    KTH, School of Technology and Health (STH), Medical Engineering.
    Peolsson, Michael
    KTH, School of Technology and Health (STH).
    Winter, Reidar
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Wave intensity wall analysis: a novel noninvasive method to measure wave inntensity2009In: Heart and Vessels, ISSN 0910-8327, E-ISSN 1615-2573, Vol. 24, p. 357-365Article in journal (Refereed)
    Abstract [en]

    Wave intensity analysis is a concept providing information about the interaction of the heart and the vascular system. Originally, the technique was invasive. Since then new noninvasive methods have been developed. A recently developed ultrasound technique to estimate tissue motion and deformation is speckle-tracking echocardiography. Speckle tracking-based techniques allow for accurate measurement of movement and deformation variables in the arterial wall in both the radial and the longitudinal direction. The aim of this study was to test if speckle tracking-derived deformation data could be used as input for wave intensity calculations. The new concept was to approximate changes of flow and pressure by deformation changes of the arterial wall in longitudinal and radial directions. Flow changes (dU/dt) were approximated by strain rate (sr, 1/s) of the arterial wall in the longitudinal direction, whereas pressure changes (dP/dt) were approximated by sign reversed strain rate (1/s) in the arterial wall in the radial direction. To validate the new concept, a comparison between the newly developed Wave Intensity Wall Analysis (WIWA) algorithm and a commonly used and validated wave intensity system (SSD-5500, Aloka, Tokyo, Japan) was performed. The studied population consisted of ten healthy individuals (three women, seven men) and ten patients (all men) with coronary artery disease. The present validation study indicates that the mechanical properties of the arterial wall, as measured by a speckle tracking-based technique are a possible input for wave intensity calculations. The study demonstrates good visual agreement between the two systems and the time interval between the two positive peaks (W1-W2) measured by the Aloka system and the WIWA system correlated for the total group (r = 0.595, P < 0.001). The correlation for the diseased subgroup was r = 0.797, P < 0.001 and for the healthy subgroup no significant correlation was found (P > 0.05). The results of the study indicate that the mechanical properties of the arterial wall could be used as input for wave intensity calculations. The WIWA concept is a promising new method that potentially provides several advantages over earlier wave intensity methods, but it still has limitations and needs further refinement and larger studies to find the optimal clinical use.

  • 31.
    Larsson, Matilda
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Claus, P.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    D'Hooge, J.
    Ultrasound-based 2D Strain Estimation of the Carotid Artery: an in-silico feasibility study2009In: Ultrasonics Symposium (IUS), 2009 IEEE International, IEEE , 2009, , p. 4p. 5441992-Conference paper (Refereed)
    Abstract [en]

    Ultrasound based estimation of arterial wall properties is commonly used to assess vessel wall stiffness in studies of vascular diseases. Recently, it was shown that the longitudinal motion of the vessel during systole can be measured using speckle tracking. However, the assessment of longitudinal strain in the vessel wall has to be further investigated. The aim of this study was to test the feasibility of simultaneous assessment of radial and longitudinal strain in the carotid artery using computer simulations. A kinematic cylindrical model of the carotid artery with realistic dimensions was constructed. The model was deformed radially according to temporal distention measured in-vivo while longitudinal deformation was the result of conservation of volume. Moreover, longitudinal motion was superimposed based on profiles obtained in-vivo. Ultrasound long axis images were simulated using a generalized convolution model (COLE) with realistic image properties. Four models with different scatterer distributions were built. For each of them, longitudinal and radial motion were estimated using normalized cross-correlation with spline interpolation to detect sub-sample motion. Radial and longitudinal strains, obtained by linear regression were compared with the ground truth from the model. The maximal systolic radial strain was estimated to be -12.77 ± 0.4% (ground truth -13.89%) while longitudinal strain was 5.21 ± 0.67% (ground truth 5.3%). This study shows the feasibility of simultaneously measuring radial and longitudinal strain in the carotid artery by making use of currently available hardware.

  • 32.
    Larsson, Tore J
    et al.
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Jansson, Malin
    AFA Swedish Labour Market Insurances.
    Brooks, Benjamin
    University of South Australia.
    Text-mining of insurance-based information: Decision support for local safety management2009In: Safety Science Monitor, ISSN 1443-8844, Vol. 13, no 1, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Based on underlying perspectives, different data tend to be included in reporting systems for occupational accidents and injuries. Information sought mainly for medical, legal, economic or statistical reasons can reduce or misrepresent the information needed for prevention.

    Actual detail of accident processes provided by local operators

    in verbatim will serve to counter misconceptions of risk distributions in the organisation and direct the focus to possible prevention measures.

    The analysis of free-text reporting of traumatic injuries, accidents and incidents promise to better represent the dynamics and detail of exposure and accident process and, when applied to valid and representative insurance data on occupational injury with the help of suitable text-mining software, will provide industry groups and local companies with decision support for prevention and safety management.

    The trial and development of text-mining software for injury prevention, in conjunction with the industry group safety information system, is described and examples from different exposure areas are given

  • 33.
    Larsson, Tore Johan
    et al.
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB. KTH, School of Technology and Health (STH), Design, Work Environment, Safety and Health, DASH.
    Hagvide, Mona-Lisa
    Svanborg, Maria
    Borell, Lena
    Falls prevention through community intervention: A Swedish example2009In: Safety Science, ISSN 0925-7535, E-ISSN 1879-1042, Vol. 48, no 2, p. 204-208Article in journal (Refereed)
    Abstract [en]

    In order to control and reduce fall-related injuries, particularly among women over the age of 55, a safety management and falls prevention campaign was structured and implemented during 2006-2007 in the small industrial town of Sodertalje, Sweden. A local campaign was launched to recruit falls prevention agents, to inform key target groups in the local community, and to educate older people about fall risks. A survey showed that the campaign had a greater impact among professionals with a special relation to fall risk than among the general population. Medical records were used in the evaluation of the outcomes. The results show that between 2005 and 2007 there was a drop of fractures related to falls in the council: an overall drop of 16.7% in the population; among men 55 or older a drop of 12%, among women 55 or older a drop of 15%, among home-dwelling women 55 or older a drop of 5.7% and among women in special accommodation a drop of 44.4%. Expressed in terms of years lost to disability (YLD), the overall drop in hip fractures treated at the local hospital between 2005 and 2007 was 48%. A comparison with National medical records for the same period shows the drop for the intervention area to be much larger than that for Sweden as a whole, although the effect was not statistically significant. The study demonstrates the advantages of a broad, community-based approach to injury prevention.

  • 34.
    Li, Xiaogai
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Ho, Johnson
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    3-D Finite Element Modeling of Brain Edema: Initial Studies on Intracranial Pressure Using COMSOL Multiphysics2009In: COMSOL Conference, 2009Conference paper (Refereed)
    Abstract [en]

    Brain edema is one of the most common consequences of serious traumatic brain injuries which is usually accompanied with increased Intracranial Pressure (ICP) due to water content increment. A three dimensional finite element model of brain edema is used to study intracranial pressure in this paper. Three different boundary conditions at the end of Cerebral Spinal Fluid (CSF) were used to investigate the boundary condition effects on the volume-pressure curve based on the current model. Compared with the infusion experiments, results from the simulations show that exponential pressure boundary condition model corresponds well with the experiment

  • 35.
    Li, Xiaogai
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Ho, Johnson
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Kleiven, Svein
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Three Dimensional Poroelastic Simulation of Brain Edema: Initial Studies on Intracranial Pressure Using Comsol Multiphysics2009In: Proceedings of European Comsol Conference, Milan, Italy, October 7 - 9, 2009Conference paper (Refereed)
  • 36.
    Lindh, Thomas
    et al.
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Orhan, Ibrahim
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Performance Control in Wireless Sensor Networks2009In: Pervasive Computing Technologies for Healthcare, 2009. PervasiveHealth 2009. 3rd International Conference on, IEEE , 2009Conference paper (Refereed)
    Abstract [en]

    This paper presents an implementation of a method for performance control in wireless body sensor networks based on measurement feedback, especially targeted for demanding healthcare applications.

  • 37.
    Lindh, Thomas
    et al.
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Orhan, Ibrahim
    KTH, School of Technology and Health (STH), Medical Engineering.
    Performance Measurements and Control in Contention-Based Wireless Sensor Networks2009In: 6th Swedish National Computer Networking Workshop (SNCNW 2009), 2009Conference paper (Refereed)
    Abstract [en]

    This paper presents an implementation of a method for performance control in wireless body sensor networks based on measurement feedback, especially targeted for demanding healthcare applications.

  • 38.
    Lindh, Thomas
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering.
    Orhan, Ibrahim
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering.
    Performance Monitoring and Control in Contention-Based Wireless Sensor Networks2009In: Proceedings of the 2009 6th International Symposium on Wireless Communication Systems, ISWCS'09, NEW YORK: IEEE conference proceedings, 2009, p. 507-511Conference paper (Refereed)
    Abstract [en]

    This paper presents a method for performance monitoring and control in wireless body sensor networks based on measurement feedback. Test results using a prototype implementation of the method are also analyzed. The method has been evaluated for demanding healthcare related applications in wireless personal area networks.

  • 39.
    Lundbäck, Anna-Karin
    et al.
    KTH, School of Technology and Health (STH).
    Mueller, Shirley A.
    Engel, Andreas
    Hebert, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology (Closed 20130701).
    Assembly of Kch, a putative potassium channel from Escherichia coli2009In: Journal of Structural Biology, ISSN 1047-8477, E-ISSN 1095-8657, Vol. 168, no 2, p. 288-293Article in journal (Refereed)
    Abstract [en]

    Attempts to explore the structure and function of Kch, a putative potassium channel of Escherichia coli have yielded varying results; potassium-associated functions have been found in vivo but not in vitro. Here the kch gene is shown to produce two proteins, full-length Kch and the large C-terminal cytosolic domain (the RCK domain). Further, these two proteins are associated at the initial stages of purification. Previous structural studies of full-length Kch claim that the isolated protein forms large aggregates that are not suitable for analysis. The results presented here show that the purified protein sample, although heterogeneous, has one major population with a mass of about 400 kDa, implying the presence of two Kch tetramers in a complex form. A three dimensional reconstruction at 25 angstrom based on electron microscopy data from negatively stained particles, revealed a 210 angstrom long and 95 angstrom wide complex in which the two tetrameric Kch units are linked by their RCK domains, giving rise to a large central ring of density. The formation of this dimer of tetramers on expression or during purification, may explain why attempts to reconstitute Kch into liposomes for activity measurements have failed.

  • 40.
    Manouras, Aristomenis
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Shahgaldi, Kambiz
    Winter, Reidar
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Nowak, Jacek
    Measurements of left ventricular myocardial longitudinal systolic displacement using spectral and colour tissue Doppler: time for a reassessment?2009In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 7, p. 12-Article in journal (Refereed)
    Abstract [en]

    Background: Echocardiographic measurements of left ventricular (LV) myocardial displacement may produce different results depending on the choice of employed modality and subjective adjustments during data acquisition and analysis. Methods: In this study, left ventricular longitudinal systolic displacement was quantified in 57 patients (31 women and 26 men, 50 +/- 16 years) using colour (colour TD) and spectral tissue Doppler (spectral TD) before and after temporal filtering (30 to 70 milliseconds in 20-millisecond steps) and changed offline gain saturation (0%, 50% and 100%), respectively. The results were compared with those obtained with anatomic M-mode. Results: Whereas only minor differences occurred between the results of colour TD and anatomic M-mode measurements, spectral TD significantly overestimated the results obtained with both these methods. However, the limits of agreement between the results produced by all three studied methods were not clinically acceptable in any of the cases. The spectral TD displacement values increased along with increasing offline gain saturation whereas the effect of temporal filtering on colour Doppler measurements was insignificant. Conclusion: Measurements of LV myocardial longitudinal displacement employing spectral TD, colour TD or anatomic M-mode produce different results, thus discouraging interchangeable use of these modalities. Whereas the results of spectral TD measurements can be significantly altered by changing offline gain setting, the effect of temporal filtering on colour TD measurements is insignificant, a fact that increases clinical practicality of the latter method.

  • 41.
    Manouras, Aristomenis
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Shahgaldi, Kambiz
    Winter, Reidar
    Nowak, Jacek
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Comparison between colour-coded and spectral tissue Doppler measurements of systolic and diastolic myocardial velocities: effect of temporal filtering and offline gain setting2009In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 10, no 3, p. 406-413Article in journal (Refereed)
    Abstract [en]

    Colour tissue Doppler (TD) has been reported to underestimate the longitudinal myocardial motion velocities measured with spectral TD. This study evaluates the effect of temporal smoothing and offline gain settings on the results of velocity measurements with these two methods and the difference between them. In 57 patients, 2D data and left ventricular velocity profiles were acquired using spectral and colour TD for a subsequent offline analysis. Longitudinal myocardial velocities were measured at unsaturated, 50%-saturated and fully saturated gain, and before and after temporal smoothing using 30, 50, and 70 ms filters, respectively. Gain level and filter width altered significantly the measured velocities. Peak systolic and early diastolic velocities were significantly higher (P < 0.001) and E/E' ratio was significantly lower (P < 0.001) with spectral TD than with colour TD, although there was a good correlation between the results of both TD modalities. The differences between the methods increased at increasing filter width and gain level. Despite good correlation of the results, spectral TD produces significantly higher myocardial velocity values and lower E/E' ratio than colour TD modality. Increasing gain and temporal smoothing alter significantly the results of velocity measurements and accentuate the difference between the two TD methods.

  • 42.
    Manouras, Aristomenis
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Shala, Arben
    Nyktari, Evangelia
    Shahgaldi, Kambiz
    Winter, Reidar
    Vardas, Panagiotis
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Nowak, Jacek
    Are measurements of systolic myocardial velocities and displacement with colour and spectral Tissue Doppler compatible?2009In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 7, p. 29-Article in journal (Refereed)
    Abstract [en]

    Background: Tissue Doppler (TD) in pulsed mode (spectral TD) and colour TD are the two modalities today available in tissue velocity echocardiography (TVE). Previous studies have shown poor agreement between these two methods when measuring myocardial velocities and displacement. In this study, the concordance between the myocardial velocity and displacement measurements using colour TD and different spectral TD procedures was evaluated. Methods: Left ventricular (LV) longitudinal systolic myocardial velocities and displacement during ejection period were quantified at the basal septal and lateral wall in 24 healthy individuals (4 women and 20 men, 34 +/- 12 years) using spectral TD, colour TD and M-mode recordings. Mean, maximal and minimal spectral TD systolic velocities and the corresponding displacement values were obtained by measurements at the outer and inner borders of the spectral velocity signal. The results were then compared with those obtained with the two other modalities used. Results: Systolic myocardial velocities derived from mean spectral TD frequencies were highly concordant with corresponding colour TD measurements (mean difference 0.10 +/- 0.54 cm/sec in septal and 0.09 +/- 0.97 cm/sec in lateral wall). Similarly, the agreement between spectral and colour TD (mean difference 0.22 +/- 0.74 mm in septal and 0.02 +/- 0.86 mm in lateral wall) as well as M-mode was good when mean spectral velocities were temporally integrated and the results did not differ statistically. Conversely, displacement values from the inner or outer border of the spectral signal differed significantly from values obtained with colour TD and M-mode (p < 0.001, in both cases). Conclusion: LV systolic myocardial measurements based on mean spectral TD frequencies are highly concordant with those provided by colour TD and M-mode. Hence, in order to maintain compatibility of the results, the use of this particular spectral TD procedure should be advocated in clinical praxis.

  • 43.
    McAllister, Anita M.
    et al.
    Linköping University.
    Granqvist, Svante
    KTH, School of Technology and Health (STH).
    White Sjölander, Peta
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Sundberg, Johan
    KTH, School of Computer Science and Communication (CSC), Speech, Music and Hearing, TMH, Music Acoustics.
    Child Voice and Noise: A Pilot Study of Noise in Day Cares and the Effects on 10 Children's Voice Quality According to Perceptual Evaluation2009In: Journal of Voice, ISSN 0892-1997, E-ISSN 1873-4588, Vol. 23, no 5, p. 587-593Article in journal (Refereed)
    Abstract [en]

    The purpose of this investigation was to study children's exposure to background noise at the ears during a normal day at the day care center and also to relate this to a perceptual evaluation of voice quality. Ten children, from three day care centers, with no history of hearing and speech problems or frequent infections were selected as subjects. A binaural recording technique was used with two microphones placed on both sides of the subject's head, at equal distance from the mouth. A portable digital audio tape (DAT) recorder (Sony TCD-D 100, Stockholm, Sweden) was attached to the subject's waist. Three recordings were made for each child during the day. Each recording was calibrated and started with three repetitions of three sentences containing only sonorants. The recording technique allowed separate analyses of the background noise level and of the sound pressure level (SPL) of each subjects' own voice. Results showed a mean background noise level for the three day care centers at 82.6 dBA Leq, ranging from 81.5 to 83.6 dBA Leq. Day care center no. 2 had the highest mean value and also the highest value at any separate recording session with a mean background noise level of 85.4 dBA Leq during the noontime recordings. Perceptual evaluation showed that the children attending this day care center also received higher values on the following voice characteristics: hoarseness, breathiness, and hyperfunction. Girls increased their loudness level during the day, whereas for boys no such change could be observed.

  • 44.
    Mårtensson, Mattias
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Olsson, Mats
    Segall, Björn
    Fraser, Alan G.
    Winter, Reidar
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    High incidence of defective ultrasound transducers in use in routine clinical practice2009In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 10, no 3, p. 389-394Article in journal (Refereed)
    Abstract [en]

    The objective was to evaluate the function of ultrasound transducers in use in routine clinical practice and thereby estimating the incidence of defective transducers. The study comprised a one-time test of 676 transducers from 7 manufacturers which were in daily use in clinical departments at 32 hospitals. They were tested with the Sonora FirstCall Test System; 39.8% exhibited a transducer error. Delamination was detected in 26.5% and break in the cable was detected in 8.4% of the tested transducers. Errors originating from the piezoelectrical elements were unusual. Delamination and short circuit occurred without significant differences between transducers from all tested manufacturers, but the errors break in the cable, weak and dead element showed a statistically significant higher frequency in transducers from certain manufacturers. The high error frequency and the risk for incorrect medical decisions when using a defective transducer indicate an urgent need for increased testing of the transducers in clinical departments.

  • 45. Olsson, Annika
    et al.
    Blomé, Mikael
    Gonzalez Guve, Bertil
    KTH, School of Technology and Health (STH), Centres, Centre for Technology in Medicine and Health, CTMH.
    Kaulio, Matti
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Industrial Work Science.
    Norell Bergendahl, Margareta
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Integrated Product Development.
    Odenrick, Per
    Organizational Factors Affecting Product Innovation Capability: Findings from the Med-Tech Industry2009In: Proceedings of the 17th International Conference on Engineering Design (ICED'09), Vol. 1 / [ed] Norell Bergendahl, M.; Grimheden, M.; Leifer, L.; Skogstad, P.; Lindemann, U., 2009, p. 157-168Conference paper (Refereed)
    Abstract [en]

    Research in innovation has created much knowledge to apply concerning tools, methods and processes. However, the challenge of allowing "space", time and competence for innovation capability development is sparsely reported. The purpose of this research is to identify how organizational and behavioral factors are affecting product innovation capability and its development in organizations. The research sets out to explore and elaborate on the research question: How can product innovation capability among organizations and individuals be improved by identifying and changing organizational factors? The individual and organizational factors need to be taken in relation to the product innovation. Theories of innovation capability, innovation and learning, innovation and creative climate are used as a basis for this research. Interviews and a creative climate questionnaire have been used for empirical input in five med-tech companies. The qualitative result elicits six factors that influence the innovation capability and its development in organizations; brings out the two most important factors from the survey and elaborate a cross analyses from the qualitative and quantitative input.

  • 46.
    Parida, Vinit
    et al.
    Luleå University of Technology.
    Berglund, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Integrated Product Development.
    Sturm, Dennis
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Grimheden, Martin
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics.
    Facilitating the Learning Environment: Initiatives within the PIEp Research School2009Conference paper (Refereed)
    Abstract [en]

    Research schools have become common phenomena in the academic world. However, we find lack of studies investigating their influence and role in the academia. This study attempts to address this gap by describing how a specific research school has evolved into an effective learning environment for the enrolled PhD students. The Product Innovation Engineering program (PIEp) is currently the largest research initiative in Product Innovation in Sweden. The PIEp research school is a part of this program, with the aim to increase innovation capabilities in the Swedish industries. Through an action-based research approach the authors, who are research school participants themselves, present the processes and the chain of events to offer knowledge transfer and to give insight into this special research environment. In this pursuit, the findings are presented in three different themes,1) the role of common interest groups, 2) common interest group activities, and c) a tiger team workshop. This paper holds major implications for other research schools and funding organizations.

  • 47.
    Pau, Ivan
    et al.
    Universidad Politecnica de Madrid.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS) (Closed 20130701).
    Lindecrantz, Kaj
    Valero, Miguel Angel
    Universidad Politecnica de Madrid.
    Carracedo, Justo
    Universidad Politecnica de Madrid.
    Home e-health system integration in the Smart Home through a common media server.2009In: EMBC: 2009 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-20, 2009, Vol. 2009, p. 6171-6174Conference paper (Refereed)
    Abstract [en]

    Home e-health systems and services are revealed as one of the most important challenges to promote Quality of Life related to Health in the Information Society. Leading companies have worked on e-health systems although the majority of them are addressed to hospital or primary care settings. The solution detailed in this paper offers a personal health system to be integrated with Smart Home services platform to support home based e-care. Thus, the home e-health system and architecture detailed in this research work is ready to supply a seamless personal care solution both from the biomedical data analysis, service provision, security guarantee and information management s point of view. The solution is ready to be integrated within the Accessible Digital Home, a living lab managed by Universidad Politécnica de Madrid for R&D activities.

  • 48. Pettersen, Jostein
    et al.
    Poksinska, Bozena
    Elg, Mattias
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    Witell, Lars
    Quality Management in Swedish industry: Concepts, practices and knowledge base2009Conference paper (Refereed)
  • 49. Poksinska, Bozena
    et al.
    Pettersen, Jostein
    Elg, Mattias
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    Witell, Lars
    Quality Improvement activities in Swedish industry: Drivers, approaches and outcomes2009Conference paper (Refereed)
  • 50. Razifar, P.
    et al.
    Hamid Muhammed, Hamed
    KTH, School of Technology and Health (STH), Medical Engineering.
    Engbrant, F.
    Svensson, P. E.
    Olsson, J.
    Bengtsson, E.
    Langstrom, B.
    Bergstrom, M.
    Performance of principal component analysis and independent component analysis with respect to signal extraction from noisy positron emission tomography data - a study on computer simulated images2009In: The Open Neuroimaging Journal, ISSN 1874-4400, E-ISSN 1874-4400, Vol. 3, p. 1-16Article in journal (Refereed)
    Abstract [en]

    Multivariate image analysis tools are used for analyzing dynamic or multidimensional Positron Emission Tomography, PET data with the aim of noise reduction, dimension reduction and signal separation. Principal Component Analysis is one of the most commonly used multivariate image analysis tools, applied on dynamic PET data. Independent Component Analysis is another multivariate image analysis tool used to extract and separate signals. Because of the presence of high and variable noise levels and correlation in the different PET images which may confound the multivariate analysis, it is essential to explore and investigate different types of pre-normalization (transformation) methods that need to be applied, prior to application of these tools. In this study, we explored the performance of Principal Component Analysis (PCA) and Independent Component Analysis (ICA) to extract signals and reduce noise, thereby increasing the Signal to Noise Ratio (SNR) in a dynamic sequence of PET images, where the features of the noise are different compared with some other medical imaging techniques. Applications on computer simulated PET images were explored and compared. Application of PCA generated relatively similar results, with some minor differences, on the images with different noise characteristics. However, clear differences were seen with respect to the type of pre-normalization. ICA on images normalized using two types of normalization methods also seemed to perform relatively well but did not reach the improvement in SNR as PCA. Furthermore ICA seems to have a tendency under some conditions to shift over information from IC1 to other independent components and to be more sensitive to the level of noise. PCA is a more stable technique than ICA and creates better results both qualitatively and quantitatively in the simulated PET images. PCA can extract the signals from the noise rather well and is not sensitive to type of noise, magnitude and correlation, when the input data are correctly handled by a proper pre-normalization. It is important to note that PCA as inherently a method to separate signal information into different components could still generate PC1 images with improved SNR as compared to mean images.

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