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  • 151.
    Broomé, Michael
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Maksuti, Elira
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Bjällmark, Anna
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Frenckner, Björn
    Janerot-Sjöberg, Birgitta
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Closed-loop real-time simulation model of hemodynamics and oxygen transport in the cardiovascular system2013In: Biomedical engineering online, ISSN 1475-925X, E-ISSN 1475-925X, Vol. 12, no 1, p. 69-Article in journal (Refereed)
    Abstract [en]

    Background: Computer technology enables realistic simulation of cardiovascular physiology. The increasing number of clinical surgical and medical treatment options imposes a need for better understanding of patient-specific pathology and outcome prediction. Methods: A distributed lumped parameter real-time closed-loop model with 26 vascular segments, cardiac modelling with time-varying elastance functions and gradually opening and closing valves, the pericardium, intrathoracic pressure, the atrial and ventricular septum, various pathological states and including oxygen transport has been developed. Results: Model output is pressure, volume, flow and oxygen saturation from every cardiac and vascular compartment. The model produces relevant clinical output and validation of quantitative data in normal physiology and qualitative directions in simulation of pathological states show good agreement with published data. Conclusion: The results show that it is possible to build a clinically relevant real-time computer simulation model of the normal adult cardiovascular system. It is suggested that understanding qualitative interaction between physiological parameters in health and disease may be improved by using the model, although further model development and validation is needed for quantitative patient-specific outcome prediction.

  • 152. Broomé, Michael
    et al.
    Maksuti, Elira
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Waldenström, Anders
    Bjällmark, Anna
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Simulation of arterial hypertension and progressive arteriosclerosis with a 0-D multipurpose cardiovascular model2013In: CMBE13: 3rd International Conference on Computational & Mathematical Biomedical Engineering, 2013, p. 433-436Conference paper (Refereed)
    Abstract [en]

    The effects of systemic vascular resistance and progressive stiffening/arteriosclerosis inthe vascular tree on arterial blood pressure is explored in a 0D cardiovascular simulationmodel. Pulse pressure is both sensitive and specific for increases in stiffness and meanarterial pressure both sensitive and specific for changes in vascular resistance.

  • 153. Brown, Shannon
    et al.
    Ortiz-Catalan, Max
    Petersson, Joel
    Rodby, Kristian
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering. University of Borås, Sweden.
    Intarsia-Sensorized Band and Textrodes for Real-Time Myoelectric Pattern Recognition2016In: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS / [ed] Patton, J Barbieri, R Ji, J Jabbari, E Dokos, S Mukkamala, R Guiraud, D Jovanov, E Dhaher, Y Panescu, D Vangils, M Wheeler, B Dhawan, AP, Institute of Electrical and Electronics Engineers (IEEE), 2016, p. 6074-6077, article id 7592114Conference paper (Refereed)
    Abstract [en]

    Surface Electromyography (sEMG) has applications in prosthetics, diagnostics and neuromuscular rehabilitation. Self-adhesive Ag/AgCl are the electrodes preferentially used to capture sEMG in short-term studies, however their long-term application is limited. In this study we designed and evaluated a fully integrated smart textile band with electrical connecting tracks knitted with intarsia techniques and knitted textile electrodes. Real-time myoelectric pattern recognition for motor volition and signal-to-noise ratio (SNR) were used to compare its sensing performance versus the conventional Ag-AgCl electrodes. After a comprehending measurement and performance comparison of the sEMG recordings, no significant differences were found between the textile and the Ag-AgCl electrodes in SNR and prediction accuracy obtained from pattern recognition classifiers.

  • 154.
    Brännmark, Mikael
    KTH, School of Technology and Health (STH), Ergonomics.
    Implementering av Lean i medelstora företag: En lärande utvärdering om hållbarutveckling2010Report (Other academic)
    Abstract [sv]

    Denna rapport är ett av delresultaten från det interaktiva forskningsprojektet Produktionslyftet, inom HELIX VINN Excellence Centre. Projektet genomförs i samarbete med Produktionslyftet, ett nationellt program för spridande av managementkonceptet Lean produktion. Syftet med forskningsprojektet är att öka kunskapen om hur hållbart utvecklingsarbete kan bedrivas, både utifrån ett program- och företagsperspektiv.

    Rapporten beskriver två delstudier, en kvalitativ och en kvantitativ, som genomförts i samarbete med elva av företagen i Produktionslyftet, tio av dem pilotföretag för programmet. Den första delstudien genomfördes under sommaren 2008, genom en intervjustudie med programmets pilotföretag, medan den andra genomfördes under våren 2009, i formen av en enkätstudie med sju av företagen i programmet. Då en interaktiv forskningsansats har använts, så har i båda fallen den insamlade empirin från de båda delstudierna återkopplats till representanter från Produktionslyftet, samt programmets finansiärer, och en gemensam tolkning och analys av empirin har gjorts. Denna gemensamma tolkning har sedan analyserats utifrån modeller kring hållbart utvecklingsarbete och resultatet från detta arbete har sedan sammanfattats i två arbetsrapporter, som har återkopplats till programmet och dess finansiärer.

    Resultaten i delstudierna, samt den gemensamma tolkningen och analysen av empirin, fokuserar Produktionslyftets coacher, samt deras arbete med företagen. Dels spelar coacherna uppenbarligen en central roll i programmets arbete med företagen, och dels är coacherna mycket uppskattade av företagen. Coachernas arbetssätt, samt hur deras arbete påverkar möjligheten för företagen att skapa en hållbar utveckling, upptar också en central del i rapporten. Detta kan sammanfattas, som att om coacherna driver på arbetet för hårt, få finns det risk att det uppstår problem för företagen, men om coacherna inte är pådrivande så finns risken att åtminstone vissa av företagen inte tar sitt ansvar för Lean-arbetet. Med andra ord, coachernas arbete med företagen utgör en svår balansgång mellan att uppfylla företagens målsättningar med Lean-arbetet, i vägning mot Produktionslyftets mål och syfte. Men resultaten pekar också på vikten av att företagen har ett tydligt ägarskap och driv i utvecklingsarbetet.

    Slutsatsen i denna rapport blir därför att om programmets utvecklingsarbete skall bli hållbart, så hänger det troligen på dels att man har duktiga och kompetenta coacher, men också att man har en väl fungerande företagsrekryteringsprocess, där företag med ett internt driv för Lean-arbetet väljs till programmet.

  • 155.
    Brännmark, Mikael
    KTH, School of Technology and Health (STH), Ergonomics.
    Lean administration: En litteraturgenomgång av lean när konceptet implementeras i kommuner2011In: FALF2011: Det nya arbetslivet, Luleå: FALF , 2011Conference paper (Refereed)
    Abstract [sv]

    Lean blir allt vanligare i svensk offentlig förvaltning. Litteraturstudier har tidigare genomförts inom sjukvård och service. Denna litteraturgenomgång fokuserar istället på kommuner. Fokus ligger på vilka former som lean-konceptet tar, hur det implementeras, vilka effekter som uppnås, samt vilka svårigheter som man stött på. Sökningar gjordes i två omgångar i fyra olika databaser under i maj 2010. Endast empiriska artiklar i peer-reviewadetidsskrifter inkluderades; studier som inom vård- eller industriliknande kontexterexkluderades. Totalt resulterade sökningen och urvalsprocessen i fem publikationer, som beskriver lean i elva verksamheter. Slutsatserna från genomgången av dessa är de studerade lean-implementeringar i hög grad utgår från en ansats som påminner om värdeflödeskartläggningar. Fokus för lean-arbetet ligger på verktyg och system för förbättringsarbete. De upplevda problemen i lean-arbetet är framför allt associerade med implementeringsansatsen, snarare än konceptet eller kontexten. Verksamheternas arbete med lean har gett mestadels positiva verksamhetseffekter, framför allt rörande effektivitet och produktivitet. Hur kunderna, och framför allt personalen, påverkats är dock osäkrare.

  • 156.
    Brännmark, Mikael
    KTH, School of Technology and Health (STH), Ergonomics.
    Lean Working Environments: An Empirical Study of 24 CompaniesImplementing Lean2010In: NES2010: Proactive Ergonomics: Implementation of ergonomics in planning of jobs, tasks, systems and environments., Stavanger, 2010Conference paper (Refereed)
    Abstract [en]

    This paper studies the perceived effects on the working conditions in 24 medium sized manufacturing companies, approximately 1.5 year into their implementation of Lean. This is studied quantitatively based on four stakeholders’ perceptions (the workers, the managers, the production supervisors and the white-collar workers), based on three factors; changes in the working environment, work with safety for the personnel and level of stress. The results indicate that the physical work environments have improved and the workers and production supervisors report a slight increase in stress. Lastly, all groups report an increase in the work with safety for the personnel.

  • 157.
    Brännmark, Mikael
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Leaninspirerade förändringar och personalens upplevelser2013In: Lean i arbetslivet / [ed] Sederblad, Per, Stockholm: Liber, 2013, 1, p. 103-121Chapter in book (Other academic)
    Abstract [sv]

    De anställdas upplevelser av hur de kommer att påverkas av ett förändringskoncept är en avgörande faktor för om konceptet kommer att få reellt genomslag eller inte. Det här kapitlet behandlar denna centrala aspekt av leankonceptet – hur personalen upplever leaninspirerade förändringar. Just denna fråga finns det mycket lite empirisk forskning kring, så väl internationellt som i Sverige.

    I kapitlet redovisas en studie av personalens erfarenheter från leanarbetet i medelstora svenska tillverkningsföretag som ingått i det nationella programmet Produktionslyftet. Programmet kan ses som ett exempel på en ”svensk tolkning” av lean. Produktionslyftet har fått stort genomslag i den svenska diskussionen om lean, men samtidigt har konsekvenserna av lean ur ett arbetsmiljöperspektiv inte utvärderats på ett genomgripande sätt.

  • 158.
    Brännmark, Mikael
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    Håkansson, Malin
    KTH, School of Technology and Health (STH), Ergonomics.
    Vogel, Kjerstin
    KTH, School of Technology and Health (STH), Ergonomics.
    Belastningsergonomiska studier utifrån ett produktions- och systemperspektiv: Kunskapsöversikt2012Report (Other academic)
  • 159.
    Brännmark, Mikael
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Halvarsson, Agneta
    Linköpings universitet, HELIX VINN Excellence Centre.
    Lindskog, Pernilla
    KTH, School of Technology and Health (STH), Ergonomics.
    Implementing Lean in Swedish Municipalities and Hospitals: Initial effects on the work system2011In: FALF2011:Det nya arbetslivet, Luleå: FALF , 2011Conference paper (Refereed)
    Abstract [en]

    This paper is the first preliminary product of a three year interactive research project, studying the effects of Lean when introduced in Swedish municipalities and hospitals. Focus of the paper is the implementation process (more specifically, employee participationand facilitated learning) and changes in the work system (focusing on work content, organization and work environment). The empirical data has been collected through interviews and group interviews in three municipalities and one hospital. These results, together with the discussion and analysis, shows firstly that the implementation processes of the studied units are characterized by a medium or high level of opportunities for employee participation and learning, although this is produced in different ways. Second, the changes in the work systems mostly affect the organization of the work, through reorganization and redistribution of the work tasks, rather than changes in how the work tasks are performed.This has lead to more orderly and structured work processes. Lastly, the employees’ reactions to these changes have been mostly positive, although not exclusively so. However, it is important to stress that the employee reactions are most likely as much a result of the implementation process, as of the changes in the work systems. Longitudinal studies are therefore needed to study the long term changes in the work system and the effects on employee health, which will be the next step of this research project.

  • 160.
    Brännmark, Mikael
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Holden, Richard J
    Departments of Medicine and Biomedical Informatics, Center for Research and Innovation in Systems Safety, Vanderbilt University School of Medicine.
    Packages of participation: Swedish employees´experience of Lean depends on how they are involved2013In: IIE Transactions on Occupational Ergonomics and Human Factors, ISSN 2157-7323, Vol. 1, no 2, p. 93-108Article in journal (Refereed)
    Abstract [en]

    Background: Lean production is a dominant approach in Swedish and global manufacturing and service industries. Studies of Lean’s employee effects are few and contradictory. Purpose: Employee effects from Lean are likely not uniform. This article investigates the effect of employees’ participation on their experiences of Lean. Method: This study investigated how different packages of employee participation in Lean affected manufacturing workers’ experiences of Lean. During 2008–2011, qualitative and quantitative data were collected from Swedish manufacturing companies participating in the national Swedish Lean production program Produktionslyftet. Data from 129 surveys (28 companies), 39 semi-structured interviews, and 30 reports were analyzed. In the main analysis, comparisons were made of the survey-reported Lean experiences of employees in three groups: temporary group employees (N = 36), who participated in Lean mostly through intermittent projects; continuous group employees (N = 69), who participated through standing improvement groups; and combined group employees (N = 24), who participated in both ways. Results: Continuous group employees had the most positive experience of Lean, followed by the combined group. Temporary group employees had the least positive experiences, being less likely than their counterparts to report that Lean improved teamwork; occupational safety; and change-related learning, decision making, and authority. Conclusions: These findings support the importance of continuous, structured opportunities for participation but raise the possibility that more participation may result in greater workload and role overload, mitigating some benefits of employee involvement. Consequently, companies should consider involving employees in change efforts but should attend to the specific design of participation activities.

  • 161.
    Brännmark, Mikael
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Håkansson, Malin
    KTH, School of Technology and Health (STH), Ergonomics.
    Lean production and work-related musculoskeletal disorders: Overviews of international and Swedish studies2012In: Work: A journal of Prevention, Assesment and rehabilitation, ISSN 1051-9815, E-ISSN 1875-9270, Vol. 41, no 1, p. 2321-2328Article in journal (Refereed)
    Abstract [en]

    This paper aimed at summarizing the knowledge of the relationship between Lean and work related musculoskeletal disorders (WMSD), and WMSD risk factors, in manufacturing companies. Literature search processes identified 23 publications studying this, in scientific journals. Eight included measurements of WMSD; three were mostly negative, two showed mixed results, one showed no results and two were mostly positive. Eighteen publications included measurements of WMSD risk factors; seven showed mostly negative results, eight snowed mixed results, two showed mostly positive results and one was inconclusive. Three literature reviews were identified, which studied this question; two were mostly negative, while the third was inconclusive. Also, 12 publications of grey literature studying Lean and WMSD risk factors in Swedish organizations were identified; nine showed mixed results, two showed mostly positive results and one showed mostly negative results. Due to the varying quality and study design of the publications, together with the few identified studies, it is difficult to compare them. The context and the implementation also likely affect the results. The general conclusion was that a Lean implementation may increase the risk of WMSD and risk factors for WMSD, if it is not accompanied with an ergonomic intervention.

  • 162.
    Brännmark, Mikael
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Langstrand, Jostein
    Linköping University, Division of Quality Technology and Management, Linköping, Sweden.
    Johansson, Stina
    Luleå University of Technology, Dept. of Human Work Science, Luleå, Sweden.
    Halvarsson, Agneta
    Linköpings universitet, HELIX VINN Excellence Centre.
    Abrahamsson, Lena
    Luleå University of Technology, Dept. of Human Work Science, Luleå, Sweden.
    Winkel, Jörgen
    University of Gothenburg, Dept. of Sociology and Work Science, Gothenburg, Sweden.
    Researching lean: Methodological implications of loose definitions2012In: Quality Innovation Prosperity, ISSN 1335-1745, E-ISSN 1338-984X, Vol. 16, no 2, p. 35-48Article in journal (Refereed)
    Abstract [en]

    Recently, Lean Production (Lean) has become a prevailing management concept in Sweden. However, previous research seems to show that the Lean concept and the impact of Lean vary considerably between organizations.

    This paper illustrates some key methodological issues that need to be considered when researching loosely defined management concepts such as Lean. The paperis based on a review of the literature and five comparative Swedish cases studies.

    Our study indicates that Lean has changed over time and that operationalization and interpretations of the concept vary considerably

    This study concludes that future Lean studies should include a thorough assessment of the Lean interventions, study settings, and in particular non-Lean factors mediating the outcomes of Lean-inspired change programs.

  • 163.
    Brännmark, Mikael
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Lindskog, Pernilla
    KTH, School of Technology and Health (STH), Ergonomics.
    Halvarsson, Agneta
    Linköpings universitet, HELIX VINN Excellence Centre.
    Patient Quality Effects from Lean Healthcare: An Empirical Investigation2012In: NES2012 Proceedings.: Ergonomics for sustainability and growth / [ed] Ann-Beth Antonsson, Göran Hägg, Stockholm: KTH Royal Institute of Technology, 2012Conference paper (Refereed)
    Abstract [en]

    The use of Lean in healthcare settings has become common in Swedish hospitals. However, the effects from Lean on patients have not been studied extensively. This paper contributes to our understanding of this question, based on 24 semi-structured interviews in three municipal care units and three units in hospitals. The results indicate that there may be a positive link between Lean activities and quality of care. However, it is plausibly a weak link, heavily modulated by non-Lean factors. Thus, we need more empirical research to understand the causal link between patient safety and quality of care from Lean Healthcare.

  • 164.
    Bu, Yi-Qin
    et al.
    KTH, School of Technology and Health (STH).
    Wang, Jieyu
    KTH, School of Technology and Health (STH).
    Overview of Care Coordination Within Specialized Home Care in Stockholm County2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The ageing population of Sweden is expected to increase throughout the future decades. Changing life-style trends and smaller families in the modern society has decreased the population’s access to informal care. This is expected to entail an increase in the services provided by specialized home care. This thesis studies the work performed by nurses within the department of specialized home care (ASIH) in Stockholm County. The nurses represent the majority of all professions active at ASIH in Stockholm County, which puts their work in particular interest for this thesis. The thesis focuses on the ways the nurses’ work procedures may influence continuity of care and patient safety. Continuity of care is an essential component in qualitative care and is characterized by well-executed coordination and minimization of broken patient appointments. A high level of continuity of care consequently entails a high level of patient safety. Descriptions of continuity of care at ASIH in Stockholm County can therefore provide indications on current care quality and areas of improvement.

    The thesis consists of two parts – a literature review containing international research on continuity within home care and an empirical study containing a retrospective analysis based on the Functional Resonance Analysis Method (FRAM). The empirical study creates an overview of work tasks related to nursing performed at three units of ASIH in Stockholm County. The interdependencies between work tasks are identified and important chain reactions are analyzed.

    The findings from this thesis indicate that extended training programs for nurses in the initial phase of employment is likely to decrease the number of disruptions in the nurses’ work. Furthermore, well-developed routines could facilitate work task procedures which would decrease the number of delays and disruptions in the nurses’ work. It was found that these findings together with information continuity between all parties involved represent significant factors for attaining continuity of care and patient safety at ASIH in Stockholm County.

  • 165.
    Buendia, Ruben
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Improvements in Bioimpedance SpectroscopyData Analysis: Artefact Correction, ColeParameters, and Body Fluid Estimation2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The estimation of body fluids is a useful and common practice in the status assessment of diseasemechanisms and treatments. Electrical bioimpedance spectroscopy (EBIS) methods are non-invasive,inexpensive, and efficient alternatives for the estimation of body fluids. However, these methods areindirect, and their robustness and validity are unclear.Regarding the recording of measurements, a controversy developed regarding a spectrum deviationin the impedance plane, which is caused by capacitive leakage. This deviation is frequentlycompensated for by the extended Cole model, which lacks a theoretical basis; however, there is nomethod published to estimate the parameters. In this thesis, a simplified model to correct thedeviation was proposed and tested. The model consists of an equivalent capacitance in parallel withthe load.Subsequently, two other measurement artefacts were considered. Both artefacts were frequentlydisregarded with regard to total body and segmental EBIS measurements as their influence isinsignificant with suitable skin-electrode contact. However, this case is not always valid, particularlyfrom a textile-enabled measurement system perspective. In the estimation of body fluids, EBIS dataare fitted to a model to obtain resistances at low and high frequencies. These resistances can berelated to body fluid volumes. In order to minimise the influence of all three artefacts on theestimation of body fluids and improve the robustness and suitability of the model fitting the differentdomains of immittance were used and tested. The conductance in a reduced frequency spectrum wasproposed as the most robust domain against the artefacts considered.The robustness and accuracy of the method did not increase, even though resistances at low and highfrequencies can be robustly estimated against measurement artefacts. Thus, there is likely error in therelation between the resistances and volumes. Based on a theoretical analysis, state of the artmethods were reviewed and their limitations were identified. New methods were also proposed. Allmethods were tested using a clinical database of patients involved in growth hormone replacementtherapy. The results indicated EBIS are accurate methods to estimate body fluids, however they haverobustness limits. It is hypothesized that those limits in extra-cellular fluid are primarily due toanisotropy, in total body fluid they are primarily due to the uncertainty ρi, and errors in intra-cellularfluid are primarily due to the addition of errors in extracellular and total body fluid. Currently, theseerrors cannot be prevented or minimised. Thus, the limitations for robustness must be predicted priorto applying EBIS to estimate body fluids.

  • 166.
    Buendia, Ruben
    et al.
    University of Borås, Sweden.
    bogonez-franco, Paco
    Technical University of Catalonia.
    Nescolarde, Lexa
    Technical University of Catalonia.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Influence of electrode mismatch on Cole parameter estimation from Total Right Side Electrical Bioimpedance Spectroscopy measurements2012In: Medical Engineering and Physics, ISSN 1350-4533, E-ISSN 1873-4030, Vol. 34, no 7, p. 1024-1028Article in journal (Refereed)
    Abstract [en]

    Applications based on measurements of Electrical Bioimpedance (EBI) spectroscopy analysis, like assessment of body composition, have proliferated in the past years. Currently Body Composition Assessment (BCA) based in Bioimpedance Spectroscopy (BIS) analysis relays on an accurate estimation of the Cole parameters R-0 and R-infinity. A recent study by Bogonez-Franco et al. has proposed electrode mismatch as source of remarkable artefacts in BIS measurements. Using Total Right Side BIS measurements from the aforementioned study, this work has focused on the influence of electrode mismatch on the estimation of R-0 and R-infinity using the Non-Linear Least Square curve fitting technique on the modulus of the impedance. The results show that electrode mismatch on the voltage sensing electrodes produces an overestimation of the impedance spectrum leading to a wrong estimation of the parameters R-0 and R-infinity, and consequently obtaining values around 4% larger that the values obtained from BIS without electrode mismatch. The specific key factors behind electrode mismatch or its influence on the analysis of single and spectroscopy measurements have not been investigated yet, no compensation or correction technique is available to overcome the deviation produced on the EBI measurement. Since textile-enabled EBI applications using dry textrodes, i.e. textile electrodes with dry skin-electrode interfaces and potentially large values of electrode polarization impedance are more prone to produce electrode mismatch, the lack of a correction or compensation technique might hinder the proliferation of textile-enabled EBI applications for personalized healthcare monitoring.

  • 167.
    Buendia, Ruben
    et al.
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Gil-Pita, Roberto
    Department of Theory of the Signal and Communications.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Cole Parameter Estimation from the Modulus of the Electrical Bioimpeadance for Assessment of Body Composition: A Full Spectroscopy Approach2011In: Journal of Electrical Bioimpedance, ISSN 1891-5469, E-ISSN 1891-5469, Vol. 2, p. 72-78Article in journal (Refereed)
    Abstract [en]

    Activities around applications of Electrical Bioimpedance Spectroscopy (EBIS) have proliferated in the past decade significantly. Most of these activities have been focused in the analysis of the EBIS measurements, which eventually might enable novel applications. In Body Composition Assessment (BCA) the most common analysis approach currently used in EBIS is based on the Cole function, which most often requires curve fitting. One of the most implemented approaches for obtaining the Cole parameters is performed in the impedance plane through the geometrical properties that the Cole function exhibit in such domain as depressed semi-circle. To fit the measured impedance data to a semi-circle in the impedance plane, obtaining the Cole parameters in an indirect and sequential manner has several drawbacks. Applying a Non-Linear Least Square (NLLS) iterative fitting on the spectroscopy measurement, obtains the Cole parameters considering the frequency information contained in the measurement. In this work, from experimental total right side EBIS measurements, the BCA parameters have been obtained to assess the amount and distribution of whole body fluids. The values for the BCA parameters have been obtained using values for the Cole parameters estimated with both approaches: circular fitting on the impedance plane and NLLS impedance-only fitting. The comparison of the values obtained for the BCA parameters with both methods confirms that the NLLS impedance-only is an effective alternative as Cole parameter estimation method in BCA from EBIS measurements. Using the modulus of the Cole function as the model for the fitting would eliminate the need for performing a phase detection in the acquisition process, simplifying the hardware specifications of the measurement instrumentation when implementing a bioimpedance spectrometer.

  • 168.
    Buendia, Ruben
    et al.
    School of Engineering, University of Borås.
    Gil-Pita, Roberto
    Department of Theory of the Signal and Communications, University of Alcala, Madrid, Spain.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Cole parameter estimation from total right side electrical bioimpedance spectroscopy measurements: Influence of the number of frequencies and the upper limit2011In: 2011 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC), 2011, p. 1843-1846Conference paper (Refereed)
    Abstract [en]

    Applications based on measurements of Electrical Bioimpedance Spectroscopy (EBIS) analysis are proliferating. The most spread and known application of EBIS is the non-invasive assessment of body composition. Fitting to the Cole function to obtain the Cole parameters, R<sub>0</sub> and R<sub>&#x221E;</sub>, is the core of the EBIS analysis to obtain the body fluid distribution. An accurate estimation of the Cole parameters is essential for the Body Composition Assessment (BCA) and the estimation process depends on several factors. One of them is the upper frequency limit used for the estimation and the other is the number of measured frequencies in the measurement frequency range. Both of them impose requirements on the measurement hardware, influencing largely in the complexity of the bioimpedance spectrometer. In this work an analysis of the error obtained when estimating the Cole parameters with several frequency ranges and different number of frequencies has been performed. The study has been done on synthetic EBIS data obtained from experimental Total Right Side (TRS) measurements. The results suggest that accurate estimations of R<sub>0</sub> and R<sub>&#x221E;</sub> for BCA measurements can be achieved using much narrower frequency ranges and quite fewer frequencies than electrical bioimpedance spectrometers commercially available nowadays do.

  • 169.
    Buendia, Ruben
    et al.
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Bosacus, I.
    University of Gothenburg.
    Gil-Pita, Roberto
    Department of Theory of the Signal and Communications, University of Alcala, Madrid, Spain.
    Johannsson, G.
    Ellegård, L.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Robust approach against capacitive coupling for the estimation of body fluids using clinical bioimpedance spectroscopy measurementsManuscript (preprint) (Other academic)
  • 170.
    Buendia, Ruben
    et al.
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Gil-Pita, Roberto
    Department of Theory of the Signal and Communications, University of Alcala, Madrid, Spain.
    Experimental validation of a method for removing the capacitive leakage artifact from electrical bioimpedance spectroscopy measurements2010In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 21, no 11Article in journal (Refereed)
    Abstract [en]

    Often when performing electrical bioimpedance (EBI) spectroscopy measurements, the obtained EBI data present a hook-like deviation, which is most noticeable at high frequencies in the impedance plane. The deviation is due to a capacitive leakage effect caused by the presence of stray capacitances. In addition to the data deviation being remarkably noticeable at high frequencies in the phase and the reactance spectra, the measured EBI is also altered in the resistance and the modulus. If this EBI data deviation is not properly removed, it interferes with subsequent data analysis processes, especially with Cole model-based analyses. In other words, to perform any accurate analysis of the EBI spectroscopy data, the hook deviation must be properly removed. Td compensation is a method used to compensate the hook deviation present in EBI data; it consists of multiplying the obtained spectrum, Z meas (ω), by a complex exponential in the form of exp(–jωTd). Although the method is well known and accepted, Td compensation cannot entirely correct the hook-like deviation; moreover, it lacks solid scientific grounds. In this work, the Td compensation method is revisited, and it is shown that it should not be used to correct the effect of a capacitive leakage; furthermore, a more developed approach for correcting the hook deviation caused by the capacitive leakage is proposed. The method includes a novel correcting expression and a process for selecting the proper values of expressions that are complex and frequency dependent. The correctness of the novel method is validated with the experimental data obtained from measurements from three different EBI applications. The obtained results confirm the sufficiency and feasibility of the correcting method.

  • 171.
    Buendia, Ruben
    et al.
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Harris, Matthew
    Phillips Research.
    Caffarel, Jeniffer
    Phillips Research.
    Gil-Pita, Roberto
    Department of Theory of the Signal and Communications, University of Alcala, Madrid, Spain.
    Hook Effect correction & resistance-based Cole fitting prior Cole model-based analysis: Experimental validation2010In: Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2010, IEEE Engineering in Medicine and Biology , 2010, p. 6563-6566Conference paper (Refereed)
    Abstract [en]

    The analysis of measurements of Electrical Bioimpedance (EBI) is on the increase for performing non-invasive assessment of health status and monitoring of pathophysiological mechanisms. EBI measurements might contain measurements artefacts that must be carefully removed prior to any further analysis. Cole model-based analysis is often selected when analysing EBI data and might lead to miss-conclusion if it is applied on data contaminated with measurement artefacts. The recently proposed Correction Function to eliminate the influence of the Hook Effect from EBI data and the fitting to the real part of the Cole model to extract the Cole parameters have been validated on experimental measurements. The obtained results confirm the feasible experimental use of these promising pre-processing tools that might improve the outcome of EBI applications using Cole model-based analysis.

  • 172.
    Buendia, Ruben
    et al.
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS) (Closed 20130701). University of Alcala, Spain; Chalmers University of Technology, Sweden; University of Boras, Sweden.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS) (Closed 20130701). University of Boras, Sweden.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS) (Closed 20130701). University of Boras, Sweden; Karolinska Instituet, Sweden.
    Bosacus, I.
    University of Gothenburg.
    Gil-Pita, Roberto
    Department of Theory of the Signal and Communications, University of Alcala, Madrid, Spain.
    Johannsson, G.
    Ellegård, L.
    Ward, L.
    Estimation of body fluids with bioimpedance spectroscopy: state of the art methods and proposal of novel methods2015In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 36, no 10Article in journal (Refereed)
    Abstract [en]

    Determination of body fluids is a useful common practice in determination of disease mechanisms and treatments. Bioimpedance spectroscopy (BIS) methods are non-invasive, inexpensive and rapid alternatives to reference methods such as tracer dilution. However, they are indirect and their robustness and validity are unclear. In this article, state of the art methods are reviewed, their drawbacks identified and new methods are proposed. All methods were tested on a clinical database of patients receiving growth hormone replacement therapy. Results indicated that most BIS methods are similarly accurate (e.g. < 0.5 +/- 3.0% mean percentage difference for total body water) for estimation of body fluids. A new model for calculation is proposed that performs equally well for all fluid compartments (total body water, extra-and intracellular water). It is suggested that the main source of error in extracellular water estimation is due to anisotropy, in total body water estimation to the uncertainty associated with intracellular resistivity and in determination of intracellular water a combination of both.

  • 173.
    Buendía López, Rubén
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Model Based Enhancement of Bioimpedance Spectroscopy Analysis: Towards Textile Enabled Applications2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Several signal processing approaches have been developed to overcome the effect of stray capacitances in Electrical Bioimpedance Spectroscopy (EBIS) measurements. EBIS measurements obtained with textile-enabled instrumentation are more vulnerable to stray capacitances. Currently, the most widespread approach for correcting the effect of stray capacitances in EBIS is the time delay (

    Td) compensation method, which also has several drawbacks. In this study, the Td method is revisited and its limitations and its lack of a scientific basis are demonstrated. To determine better ways to overcome the effect of stray capacitances, a simplified measurement model is proposed that is based on previous models of artefacts in EBIS measurements described in the literature. The model consists of a current divider with a parasitic capacitance (Cpar) in parallel with the load. Cpar creates a pathway for the measurement current to leak away from the load, provoking a capacitive leakage effect. In this thesis, three approaches with different limitations are proposed to overcome the capacitive leakage effect. The first approach estimates Cpar and subtracts it from the measurements, thus finding the load. Cpar can be estimated because the susceptance of biological tissue is null at infinite frequency. Therefore, at high frequencies, the susceptance of the tissue can be neglected, and the slope of the susceptance of the measurement is Cpar. The accuracy of Cpar depends on the maximum frequency measured and the value of Cpar. Therefore, it may not be possible to accurately estimate small values of Cpar in the typical frequency ranges used in EBIS. The second and third approaches use the Cole fitting process to estimate the Cole parameters, which form the basis for most EBIS applications. Because the conductance of the measurement is free from the effect of Cpar, performing Cole fitting on the conductance avoids the effect of Cpar in the fitting process. With a poor skin-electrode contact, this approach may not be sufficiently accurate. The third approach would be to perform the Cole fitting on the modulus with a reduced upper frequency limit because the modulus and the low-medium frequencies are very robust against the effect of artefacts. In this approach, a slight capacitive leakage effect is unavoidable. Since it is common to find tainted measurements, especially among those obtained with textile-enabled instrumentation, it is important to find viable methods to avoid their effect. The three methods studied showed that they could reduce the effect of tainted measurements.

  • 174.
    Buizza, Giulia
    KTH, School of Technology and Health (STH).
    Classifying patients' response to tumour treatment from PET/CT data: a machine learning approach2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Early assessment of tumour response has lately acquired big interest in the medical field, given the possibility to modify treatments during their delivery. Radiomics aims to quantitatively describe images in radiology by automatically extracting a large number of image features. In this context, PET/CT (Positron Emission Tomography/Computed Tomography) images are of great interest since they encode functional and anatomical information, respectively. In order to assess the patients' responses from many image features appropriate methods should be applied. Machine learning offers different procedures that can deal with this, possibly high dimensional, problem.

    The main objective of this work was to develop a method to classify lung cancer patients as responding or not to chemoradiation treatment, relying on repeated PET/CT images. Patients were divided in two groups, based on the type of chemoradiation treatment they underwent (sequential or concurrent radiation therapy with respect to chemotherapy), but image features were extracted using the same procedure. Support vector machines performed classification using features from the Radiomics field, mostly describing tumour texture, or from handcrafted features, which described image intensity changes as a function of tumour depth. Classification performance was described by the area under the curve (AUC) of ROC (Receiving Operator Characteristic) curves after leave-one-out cross-validation. For sequential patients, 0.98 was the best AUC obtained, while for concurrent patients 0.93 was the best one. Handcrafted features were comparable to those from Radiomics and from previous studies, as for classification results. Also, features from PET alone and CT alone were found to be suitable for the task, entailing a performance better than random.

  • 175.
    Burmeister, Jens
    et al.
    University of Dresden, Germany.
    Lindh, Thomas
    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).
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Lundberg, Stefan
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Contention-Based Wireless Sensor Networks: A case study for ambient assisted living2010In: Active Ageing, Smart Solutions, New Markets, 2010Conference paper (Refereed)
    Abstract [en]

    Wireless personal area networks have emerged as an important communication infrastructure in areas such as at-home healthcare and home automation, independent living and assistive technology. Initiatives towards interoperability and standardization are taken by several players. Zigbee Alliance has launched a profile for “Zigbee wireless sensor applications for health, wellness and fitness” [1]. The Continua Health Alliance promotes “an interoperable personal healthcare ecosystem”. They have published “design guidelines for the telehealth ecosystem” including the interface to personal area network health devices and electronic health record devices ([2], [3]). These examples show that wireless personal area networks, including body sensor networks, are becoming more mature and are considered to be a realistic alternative as communication infrastructure for demanding services. However, to transmit vital sign parameters from ECGs, pulse-oximeters, EEGs etc in wireless networks is also a challenge, especially if multiple sensors compete for access. Contention-based access networks offer simplicity and utilization advantages, but the drawback is unpredictable performance due to loss of transmitted packets.

    We have used the SHIMMER wireless sensor platform developed at Intel [4] in the living lab at the Centre for Health and Building at KTH in a case study to identify and evaluate performance problems. The full-scale living lab consists of two apartments especially equipped with modern technique for healthcare at home and assisted living.

    Our paper focuses on continuous monitoring of the heart activity using a wireless ECG based on the wireless personal area network (WPAN) standard IEEE 802.15.4. Results from performance tests in the living lab will be presented e.g. influence of equipment such as micro wave ovens. Since contention-based wireless access has no guarantees for the quality of the delivered service it is interesting to determine to what extent the received ECG signal is sensitive to loss of information. We have recorded ECG signals as well as emulated packet loss in existing ECG records from official databases. The result of two cardiologists´ assessment of ECGs with different loss ratio levels and patterns will be reported in the paper. One interesting conclusion is that a diagnosis is fully possible for ECGs with packet loss ratio up to at least 5%. This project is part of research at the School of Technology and Health at KTH.

  • 176.
    Bährecke, Niklas
    KTH, School of Technology and Health (STH).
    Automatic Classification and Visualisation of Gas from Infrared Video Data2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Optical gas imaging denotes the visualisation of gases by means of an infrared camera, which allows operators to quickly, easily, and safely scan a large area and therefore plays a major role in the early detection and repair of gas leaks in various environments within the petrochemical industry such as processing plants and pipelines, but also in production facilities and hospitals. Thereby they help to avert damage to the environment as well as to health and safety of workers or inhabitants of nearby residential areas. The current generation of thermal gas cameras employs a so-called high-sensitivity mode, based on frame differencing, to increase the visibility of gas plumes. However, this method often results in image degradation through loss of orientation, distortion, and additional noise. Taking the increased prevalence and sinking costs for IR gas cameras – entailing an increased number of inexperienced users – into consideration, a more intuitive and user-friendly system to visualise gas constitutes a useful feature for the next generation of IR gas cameras. A system that retains the original infrared video images and highlights the gas cloud, providing the user with a clear and distinct visualisation of gas on the camera’s display, would be one example for such a visualisation system. This thesis discusses the design of such an automatic gas detection and visualisation framework based on machine learning and computer vision methods, where moving objects in video images are detected and classified as gas or non-gas based on appearance and spatiotemporal features. The main goal was to conduct a proof-of-concept study of this method, which included gathering examples for training a classifier as well as implementing the framework and evaluating several feature descriptors – both static and dynamic ones – with regard to their classification performance in gas detection in video images. Depending on the application scenario, the methods evaluated in this study are capable of reliably detecting gas.

  • 177.
    Callerström, Emma
    KTH, School of Technology and Health (STH).
    Clinicians' demands on monitoring support in an Intensive Care Unit: A pilot study, at Capio S:t Görans Hospital2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Patients treated at intensive care units (ICUs) are failing in one or several organs and requireappropriate monitoring and treatment in order to maintain a meaningful life. Today clinicians inintensive care units (ICUs) manage a large amount of data generated from monitoring devices.The monitoring parameters can either be noted down manually on a monitoring sheet or, for some parameters, transferred automatically to storage. In both cases the information is stored withthe aim to support clinicians throughout the intensive care and be easily accessible. Patient datamanagement systems (PDMSs) facilitate ICUs to retrieve and integrate data. Before managinga new configuration of patient data system, it is required that the ICU makes careful analysis ofwhat data desired to be registered. This pilot study provides knowledge of how the monitoringis performed in an Intensive Care Unit in an emergency hospital in Stockholm.The aim of this thesis project was to collect data about what the clinicians require and whatequipment they use today for monitoring. Requirement elicitation is a technique to collectrequirements. Methods used to collect data were active observations and qualitative interviews.Patterns have been found about what the assistant nurses, nurses and physicians’ require of systems supporting the clinician’s with monitoring parameters. Assistant nurses would like tobe released from tasks of taking notes manually. They also question the need for atomized datacollection since they are present observing the patient bed-side. Nurses describe a demanding burden of care and no more activities increasing that burden of care is required. Physicians require support in order to see how an intervention leads to a certain result for individual patients.The results also show that there is information about decision support but no easy way to applythem, better than the ones used today. Clinicians state that there is a need to be able to evaluatethe clinical work with the help of monitoring parameters. The results provide knowledge about which areas the clinicians needs are not supported enough by the exciting tools.To conclude results show that depending on what profession and experience the clinicians have the demands on monitoring support di↵ers. Monitoring at the ICU is performed while observing individual patients, parameters from medical devices, results from medical tests and physical examinations. Information from all these sources is considered by the clinicians and is desired to be supported accordingly before clinicians commit to action resulting in certain treatment,diagnosis and/or care.

  • 178.
    Callert Jakobsson, Helene
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Rätt från början: Att verka för användbara och tillgängliga lokaler inom hälso- och sjukvård2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    Occupational injuries are a problem in healthcare in Sweden. Both occupational accidents and most of all occupational diseases caused by great physical workloads constitute a large proportion of work related musculoskeletal disorders (MSD) of healthcare professionals. The aim of the study was to explore and describe the work process in the design teams of the building design process. The main focus was the building design process of health care buildings and the design teams where ergonomists and safety engineers are asked to participate. The purpose was to create a knowledge base consisting of this study and an appendix with methods and relevant literature. Eight people with different professions were interview. All of them had a good hold on the building design processes and on hospital architecture issues. Among them there were two ergonomists and two safety engineers. The result indicates that ergonomists and safety engineers were those who possessed the knowledge of working environment factors such as ergonomics in the building design processes. The methodology was to follow the agreed plan for the building design process established by the project Manager. Moreover the role of the ergonomists and safety engineers in the design team was to coach and supervise particularly the healthcare professionals. The main approach was to create a good dialogue and conversation and to keep a solution-oriented approach in the design team. Furthermore the most important method was to visualize drawings of Architects which made it possible for the healthcare workers to be able to audit the drawings correctly. This procedure gave the healthcare professionals a decision-making support which helped them to make well-reasoned decisions about their future work environment. The conclusion indicates that ergonomists and safety engineers are important because of their unique knowledge of working environment, especially ergonomics. Ergonomists and safety engineers need to be involved in the early phases of the building design process in order to be able to influence the design of new workspaces. The participation of these two professions in the design team may also benefit the healthcare workers with a future work environment which is largely designed according to their requirements and needs and will probably help to prevent MSDs. In the future there is a need for a specific education just for the ergonomists and the safety engineers participating in the building design process of healthcare buildings. There are great opportunities for them to develop their role towards a more prominent one in the building design process.

    Keywords: Ergonomists, safety engineers, building design process, health care architecture, methods, procedures

  • 179.
    Camling, Johan
    et al.
    KTH, School of Technology and Health (STH), Data- och elektroteknik.
    Lönnegren, Fredrik
    KTH, School of Technology and Health (STH), Data- och elektroteknik.
    Karttillämpningar för rikstäckande accessnät2013Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis describes the process of analyzing and evaluating geographic services, and the development of map applications for nationwide networks. The project was performed at DGC, a datacommunications-, telephony- and networks operator which distributes customer access across Sweden where consumers are connected to the backbone network. In whole, the task consisted of an analysis regarding the possibilities of address-to-coordinate lookup for established customer sites, displaying the access network in a map interface and developing one or more tools, aimed at supporting order processes. Architecture patterns, use-cases construed from user requests and analysis of external provider services for geocoding determined the design of the solution. Software was partially integrated in existing systems, and partially distributed as stand-alone applications. The product was finalized with a release. Read further to get a description of the monitoring tool, network mapping with KML, dealing with geographic data, and also the process of fetching coordinates for addresses.

  • 180. Campo, A. B.
    et al.
    Dirckx, J. J.
    Widman, Erik
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Waz, A. T.
    Dudzik, G.
    Abramski, K. M.
    Application of a new four-channel vibrometer for determination of atherosclerosis: Further advances towards a handheld device2016In: 2016 IEEE International Symposium on Medical Measurements and Applications, MeMeA 2016 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2016Conference paper (Refereed)
    Abstract [en]

    Cardiovascular diseases (CD) are the leading cause of death worldwide and their prevalence is expected to rise. Important in the etiology of CD is the stiffening of the large arteries (arteriosclerosis) and plaque formation (atherosclerosis) in the common carotid artery (CCA). Increasing evidence shows that both arteriosclerosis and atherosclerosis can be detected by assessing pulse wave velocity (PWV) in the CCA, and several techniques focus on the detection of PWV in this structure. In previous studies, laser Doppler vibrometry (LDV) was proposed as an approach to detect arterial stiffness. In the present work, a compact four-channel LDV system is introduced for PWV detection. Four phantom arteries were assessed mimicking real life cardiovascular pathologies. Due to the high sensitivity and the increased spatial and temporal resolution of the LDV system, PWV could be assessed, and even local changes in phantom architecture could be detected. The system could potentially be used to detect arteriosclerosis and arterial plaque during cardiovascular screening.

  • 181. Capece, Sabrina
    et al.
    Chiessi, Ester
    Cavalli, Roberta
    Giustetto, Pierangela
    Grishenkov, Dmitry
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Paradossi, Gaio
    A general strategy for obtaining biodegradable polymer shelled microbubbles as theranostic devices2013In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 49, no 51, p. 5763-5765Article in journal (Refereed)
    Abstract [en]

    Fabrication of multifunctional ultrasound contrast agents (UCAs) has been recently addressed by several research groups. A versatile strategy for the synthesis of UCA precursors in the form of biodegradable vesicles with a biocompatible crosslinked polymer shell is described. Upon ultrasound irradiation, acoustic droplet vaporization transforms such particles into microbubbles behaving as UCAs. This proof of concept entails the features of a potential theranostic microdevice.

  • 182. Capese, Sabrina
    et al.
    Chiessi, E.
    Cavalli, R.
    Giustetto, P.
    Grishenkov, Dmitry
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Paradossi, Gaio
    Diapartimento di Chimica, Università di Roma Tor Vergata.
    A general strategy for the obtainment of biodegradable polymer shelled microbubbles as theranostic device2013Conference paper (Refereed)
    Abstract [en]

    Introduction

    Fabrication of multifunctional ultrasound contrast agents (UCAs) has been addressed by many research groups.1,2 Recently a poly(vinyl alcohol) shelled microbubble 3 has shown a remarkable chemical and physical stability and versatility for the surface functionalization, leading to a platform for multimodality imaging (ultrasounds, magnetic resonance, single photon emission computer tomography) and targeting inflammation and tumours4. In this contribution we present a new strategy for the synthesis of UCAs precursors in the form of vesicles with a biodegradable crosslinked polymer shell.

    Methods

    Deposition of methacryloyl-derivative of hydrophilic and biodegradable polymers as dextran (DexMA50) or hyaluronic acid (HAMA30) on a lipid vesicle with a liquid perfluoropentane core, 5,6 followed by a photopolymerization of the methacrylate moiety allows the obtainment of polymer shelled vesicles.

    Results

    Lipid shelled vesicles with a perfluorocarbon (PFC) core (Figure 1a) undergo an acoustic droplet vaporization (ADV),7 upon ultrasounds (US) irradiation, transforming such particles into ultrasound effective microbubbles (Fig 1b). The process is reversible as the US are switched off (Fig 1c). In the “microbubble” state, i.e. during US irradiation, the system is echogenic at low mechanical index, allowing their use as UCAs. In this contribution we show that additional functions can be implemented into the microbubbles. For example, we demonstrated the possibility to obtain shells with a thermoreversible behaviour.

    Conclusions

    This new class of polymer shelled vesicles/microbubbles entails features desired in a potential theranostic microdevice.

  • 183.
    Carlid, Olle
    et al.
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB. KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Hjelm, Mats
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Arbetsmetodik för att minska vattenfotavtrycket: Exemplet Ornö, Haninge2010Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract

    In today's society is a large shipment of virtual water between countries in the world. Virtual water refers to all the water consumed to produce a product. From this standpoint, Sweden is importing virtual water from Brazil when we import coffee. Hoekstra and Chapagain have calculated that one cup of coffee contains 140 liters of virtual water. This water is all the freshwater that is consumed in Brazil to grow, package and carry the goods to Sweden. Fresh water is something that exists in limited quantities. In Sweden we have plenty of fresh water, but many of the countries we are importing virtual water from there is a shortages of fresh water. As an example, Sweden is importing large quantities of virtual water from countries like Germany, Spain and India, which today consumes between 40-50% of their renewable water resources. With an increased population and as the temperature increases, this consumption is going to be problematic.

    In order to analyze how much fresh water is actually needed in a country, territory, region or similar Arjen Y. Hoekstra introduced the water footprint concept in year 2002. Water footprint is defined as the volume of water that goes in to producing the products and services consumed in that area. The water footprint is divided into two parts, internal and external water footprint. With the internal water footprint means the total volume of water used by the domestic water in the national economy, minus the virtual water exported to other areas. The external water footprint is defined as the annual volume of water used in other countries to produce the goods consumed in the area and is the part that this degree thesis will be focused on.

    Sweden's total water footprint is estimated to 2150 m

    3/inhabitants/year, this can be taken in relation to the global average, which is 1564 m3

    /inhab/year. Daily the average Swede consumes an average of 5890 liters of water/person/day. 4240 liters of this (72 %) is related to agricultural products, 1320 liters (22.4 %) for industrial products and only 330 liters (5.6 %) water used in the household.

    The purpose of this degree thesis is to develop a methodology for identifying the products that cause a large external water footprint for a local community, how this society affects global water consumption in the form of virtual water and how it can be reduced. The methodology is a step-by-step approach and is divided into four phases. Phase 1. Delimit the study area, Phase 2. Identify the water footprint, Phase 3. Planning measures to reduce external water footprint, Phase 4. Analyze the results. The methodology describes what to think about, what is missing and how to calculate when you want to calculate a local society's external water footprint. The degree thesis is using Ornö as an example to apply the presented methodology on.

    Our example, Ornö, is an island in the Stockholm archipelago. The island which is located in Haninge municipality is sparsely populated, 5.7 inhabitants per square kilometer, compared to iv

    Sweden as a country, which has 22.8 inv/km

    2

    . This means that there is much access to fresh water and good farming opportunities on the island.

    The degree thesis identifies 17 agricultural products that accounts for 60 % of Sweden's external water footprint. Of these 17 products coffee is the individual crop, which accounts for the bulk of Sweden's external water footprint, 16.3 %. In addition to coffee, meat products accounts for about 16 % of the footprint. All of these 17 products are not products that can be replaced with local production. Because of the Swedish climate not all crops are fit to grow there, such as coffee. However, the study shows that 35% of the external water footprint can be replaced with local production.

    To make a study, at a local community, it is above all statistics and data on consumption in the current society that is missing. To overcome this, we see two main solutions. The first is through a detailed survey that produces what people in the society consume in detail. A second solution could be that the Statistiska centralbyrån (SCB), or a similar organization, did a survey on what people in the country with different incomes, ages or other groupings are consuming. In order to transfer it back to the residents in the local community

  • 184.
    Carlsson, Tor
    KTH, School of Technology and Health (STH).
    Individualized Motion Monitoring by Wearable Sensor: Pre-impact fall detection using SVM and sensor fusion2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Among the elderly, falling represents a major threat to the individual health, and is considered as a major source of morbidity and mortality. In Sweden alone, three elderly are lost each day in accidents related to falling. The elderly who survive the fall are likely to be suffering from decreased quality of life. As the percentage of elderly increase in the population worldwide, the need for preventive methods and tools will grow drastically in order to deal with the increasing health-care costs. This report is the result of a conceptual study where an algorithm for individualized motion monitoring and pre-impact fall detection is developed. The algorithm learns the normal state of the wearer in order to detect anomalous events such as a fall. Furthermore, this report presents the requirements and issues related to the implementation of such a system. The result of the study is presented as a comparison between the individualized system and a more generalized fall detection system. The conclusion is that the presented type of algorithm is capable of learning the user behaviour and is able to detect a fall before the user impacts the ground, with a mean lead time of 301ms.

  • 185.
    Carlsson-Kanyama, Annika
    et al.
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Thunqvist, Eva-Lotta
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB. KTH, School of Technology and Health (STH), Health Systems Engineering.
    Larsson, Tore J
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Odla under tak i eller nära bostaden2014Report (Other academic)
    Abstract [en]

    Within a project called “The sustainable greenhouse as a complement to buildings” financed by the Delegation of sustainable cities in Sweden, researchers, consultants and students have during 2013 developed, tested and evaluated various solutions for cultivating under roofs in or close to dwellings. We included solutions such as cultivating a plot in a rooftop greenhouse, a circular cultivation balcony or to cultivate in one’s kitchen or living room using a fish and vegetable furniture, a green wall, a green lamp or a green frame attached to the wall. The practical trials were preceded by a literature survey that described good examples of cultivation under roofs in various cities around the world.The results show that here are many inspiring examples of cultivating under roofs in cities and that such cultivation has gained some momentum. Our practical trials show among others that urban agriculture seems challenging and appealing for many but that the solutions that we have tested seem to be too expensive and partly also too time-consuming. Those who like to cultivate do so because it is fun and they can get products of good quality. To lessen the environmental impacts are also a reason but here our results that productivity in urban farming has to be higher than in our trials in order for the products to be considered as “climate-friendly”. Growing fish at home showed to be rather unpopular and many thought that slaughtering the fish by themselves would be nasty. Others results from the project are a water cooled LED lamp built in four copies and successfully installed in a fish and vegetable production unit as well as drawings and costs estimates for a cultivation bench.Proposals for further studies include analysis of flight and nutrient requirements for cultivation under roofs in cities as well as measurements of productivity. More low cost solutions for cultivating under glass should also be developed. To expand and maintain interest and knowledge for cultivation under roofs in cities is not only important for increasing social sustainability and eventually the environmental one as well but also because of the need to enhance preparedness.

  • 186.
    Carlström, Malin
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Design for Human Behaviour and Automation: Development and Evaluation of a Holistic Warning Approach2014Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A human-centered approach when developing new support systems in vehicles has the potential to enable the driver to make safe decisions in the transition between manual and automatic control. However, careful considerations have to be taken. Not only would the design of the systems, in terms of interface be important, but also what kind of activities the systems support. The aim of this study was to identify an appropriate activity to support the cognitive processes for truck drivers, develop an interface for this activity, and evaluate it in driving situations. This was executed in three sub-studies: the Pre-study, the Design-study, and the Evaluation study.

    In the Pre-study, the aim was to investigate for what kind of driver-related activity distribution and long haulage truck drivers need a driver support and interface. This was investigated via contribution from truck drivers, HMI/Ergonomics experts, as well as engineers. The activity chosen to support was detecting objects around the vehicle. However, reconsiderations were made due to constrains in the simulator. Suggested by Scania’s Vehicle Ergonomics group a holistic system was chosen; an interface approach enabling for more technologies to be included within the same interface, reducing the amount of modalities a driver can be exposed to.

    The Design-study addressed the aim of designing an interface for the Holistic system with truck drivers’ cognitive workload in focus. A LED-prototype was built running along the window edges inside the cab of Shania’s Vehicle Ergonomics groups’ simulator, to create warning signal concepts. Literature findings, the LED-prototype, and the simulator were used in an iterative process to design and improve warning signal concepts, until two final concepts were created. The holistic system informs of hazards around and near the vehicle by lighting the area risky objects occurs to guide drivers’ attention and this was done either with 1) the informative display or, 2) the directional display. The Informative display conveys information of a hazard location and type, and the Directional display exclusively conveys information of the hazard location.

    The Evaluation study explored how drivers were affected by, and how they perceived, the holistic interface design regarding mental workload and hazard detection. A user simulator test was designed to collect data within the areas of ‘Event detection’, ‘Workload’, ‘Driving performance’ and ‘Subjective opinion’. Fourteen professional truck drivers assessed three conditions: 1) Baseline (driving without a system), 2) the Informative display, and, 3) the Directional display, while being exposed to potential hazards. To further increase workload, a secondary task was performed at the end of each condition.

    The results showed that the Informative display did not only result in more ‘Detection hits’, instances when a driver responded to a present hazard, but also significantly decreased reaction time to detect a hazard. However, in terms of acceptance, the two concepts were considered equally preferred. As the Informative display showed to be more efficient in terms of hazard detection, this should be investigated further. A holistic interface enables for more systems to be included within the same interface, reducing the amount of alarms and modalities drivers are exposed to if designed skillfully. Thus, more support systems can be included in future vehicles, without causing unnecessary distraction when applying a holistic interface approach.

  • 187.
    Carnevale Lon, Sergio Christian
    KTH, School of Technology and Health (STH).
    A new helmet testing method to assess potential damages in the Brain and the head due to rotational energy2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Preservation and protection of the head segment is of upmost importance due to the criticality of the functions entailed in this section of the body by the brain and the nervous system. Numerous events in daily life situations such as transportation and sports pose threats of injuries that may end or change a person’s life.

    In the European Union, statistics report that almost 4.2 million of road users are injured non-fatally, out of which 18% is represented by motorcyclist and 40% by cyclists, being head injuries 34% for bicyclists, and 24% for two-wheeled motor vehicles. Not only vehicles, are a source of injuries for the human head according to the injury report, 6,1 million people are admitted in hospitals for sports related injuries, where sports such as hockey, swimming, cycling presented head injuries up to 28%, 25% and 16% respectively (European Association for Injury Prevention and Safety Promotion, 2013). 

    According to records the vast majority of head crashes result in an oblique impact (Thibault & Gennarelli, 1985). These types of impacts are characterized for involving a rotation of the head segment which is correlated with serious head injuries. Even though there is plenty of evidence suggesting the involvement of rotational forces current helmet development standards and regulations fail to recognize their importance and account only for translational impact tests.

    This thesis contains an evaluation for a different developed method for testing oblique impacts. In consequence a new test rig was constructed with basis on a guided free fall of a helmeted dummy head striking an oblique (angled) anvil which will induce rotation.

    The results obtained are intended to be subjected to a comparison with another oblique test rig that performs experiments utilizing a movable sliding plate which when impacted induces the rotation of a dropped helmeted dummy head. The outcome will solidify the presence of rotational forces at head-anvil impact and offer an alternative testing method.

    After setting up the new test rig; experiments were conducted utilizing bicycle helmets varying the velocities before impact from 5m/s to 6m/s crashing an angled anvil of 45°. Results showed higher peak resultant values for rotational accelerations and rotational velocities in the new test rig compared to the movable plate impact test, indicating that depending on the impact situation the “Normal Force” has a direct effect on the rotational components. On the other hand a performed finite element analysis predicted that the best correlation between both methods is when the new angled anvil impact test is submitted to crashes with a velocity before impact of 6 m/s at 45° and the movable sliding impact test to a resultant velocity vector of 7,6m/s with an angle of 30° .

    In conclusion the new test method is meant to provide a comparison between two different test rigs that will undoubtedly have a part in the analysis for helmet and head safety improvements.

  • 188.
    Carniello, Vera
    KTH, School of Technology and Health (STH).
    Tailoring interactions betweendegradable polymers and proteins,exploiting nanodiamond particlesand Quartz Crystal Microbalance2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Quartz Crystal Microbalance (QCM) is a sensitive and effective technique to analyze mass changes at the interface between a solid material and a liquid environment. In this Master thesis, QCM was employed for evaluating the interactions between selected degradable polymers and nanodiamond particles (nDP), fibronectin and the growth factor BMP-2.

     

    Many parameters must be adapted to allow QCM measurements involving degradable polymers. These parameters were then tailored to allow QCM measurements with PLA, poly(LLA-co-CL), poly(TMC-D-LA) and PS.

     

    Moreover, QCM provides quantitative measurements of protein adsorption on degradable polymers. The behavior of PLA and poly(LLA-co-CL) was further evaluated and compared with respect to protein adsorption. This behavior was demonstrated to be different for the two polymers considered and to be dependent on protein concentration in solution.

     

    Eventually, exploiting QCM it was also possible to assess the relationship between nDP and the adsorption of fibronectin and BMP-2 onto PLA and poly(LLA-co-CL).

  • 189.
    Cederlöf, Henrik
    KTH, School of Technology and Health (STH).
    Jag ska bara...: Om attityder, beteenden och värderingar gällande personlig skyddsutrustning i byggbranschen2013Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna magisteruppsats undersöker vilka attityder, värderingar och beteenden som arbetsgivare och yrkesarbetare i den svenska byggbranschen har då det gäller användningen av personlig skyddsutrustning.

  • 190.
    Charalampidis, Vasileios
    KTH, School of Technology and Health (STH).
    Real-Time Monitoring System of Sedentary Behavior with Android Wear and Cloud Computing: An office case study2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nowadays, prolonged sitting among office workers is a widespread problem, which is highly related to several health problems. Many proposals have been reported and evaluated to address this issue. However, motivating and engaging workers to change health behavior to a healthier working life is still a challenge.

    In this project, a specific application has been deployed for real-time monitoring and alerting office workers for prolonged sitting. The proposed system consists of three distinct parts: The first one is an android smartwatch, which was used to collect sensor data e.g., accelerometer and gyro data, with a custom android wear app. The second one is an android application, which was developed to act as a gateway for receiving the smartwatch’s data and sending them to IBM Bluemix cloud with MQTT protocol. The final part is a Node-Red cloud application, which was deployed for storing, analyzing and processing of the sensor data for activity detection i.e., sitting or walking/standing. The main purpose of the last one was to return relevant feedback to the user, while combining elements from gaming contexts (gamification methods), for motivating and engaging office workers to a healthier behavior.

    The system was firstly tested for defining appropriate accelerometer thresholds to five participants (control group), and then evaluated with five different participants (treatment group), in order to analyze its reliability for prolonged sitting detection. The results showed a good precession for the detection. No confusing between sitting and walking/standing was noticed. Communication, storage and analysis of the data was successfully done, while the push notifications to the participants, for alerting or rewarding them, were always accurate and delivered on time. Every useful information was presented to the user to a web-based dashboard accessed through a smartphone, tablet or a PC.    

    The proposed system can easily be implemented at a real-life scenario with office workers. Certainly, there is a lot space for improvement, considering mostly the type of data registered at the system, the method for sitting detection, and the user interface for presenting relevant information.

  • 191.
    Chen, Fengnong
    et al.
    KTH, School of Technology and Health (STH). College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
    Chen, Pulan
    Muhammed, Hamed Hamid
    KTH, School of Technology and Health (STH).
    Zhang, Juan
    Intravoxel Incoherent Motion Diffusion for Identification of Breast Malignant and Benign Tumors Using Chemometrics2017In: BioMed Research International, ISSN 2314-6133, E-ISSN 2314-6141, article id 3845409Article in journal (Refereed)
    Abstract [en]

    Theaim of the paper is to identify the breast malignant and benign lesions using the features of apparent diffusion coefficient (ADC), perfusion fraction f, pseudodiffusion coefficient D*, and true diffusion coefficient D from intravoxel incoherent motion (IVIM). There are 69 malignant cases (including 9 early malignant cases) and 35 benign breast cases who underwent diffusion-weighted MRI at 3.0 T with 8 b-values (0 similar to 1000 s/mm(2)). ADC and IVIM parameters were determined in lesions. The early malignant cases are used as advanced malignant and benign tumors, respectively, so as to assess the effectiveness on the result. A predictive model was constructed using Support VectorMachine Binary Classification (SVMBC, also known Support VectorMachine Discriminant Analysis (SVMDA)) and Partial Least Squares Discriminant Analysis (PLSDA) and compared the difference between them both. The.. value and ADC provide accurate identification of malignant lesions with.. = 300, if early malignant tumor was considered as advanced malignant (cancer). The classification accuracy is 93.5% for cross-validation using SVMBC with ADC and tissue diffusivity only. The sensitivity and specificity are 100% and 87.0%, respectively, r(2) (cv) = 0.8163, and root mean square error of cross-validation (RMSECV) is 0.043. ADC and IVIM provide quantitative measurement of tissue diffusivity for cellularity and are helpful with the method of SVMBC, getting comprehensive and complementary information for differentiation between benign and malignant breast lesions.

  • 192.
    Chen, Hongjian
    KTH, School of Technology and Health (STH).
    Towards the Development of the Dual Modal Contrast Agent for Computed Tomography and Ultrasound2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nowadays hybrid imaging modalities are new trends in medical imaging. To improve the diagnostic outcome of hybrid imaging, multimodal contrast agents need to be developed. For example, hybrid contrast agents for computer tomography and ultrasound (CACTUS) are one of those desirable hybrid contrast agents for the modern medical imaging.

    Polyvinyl alcohol (PVA) micro-bubbles (MBs) are one of the latest generations of ultrasound contrast agents (UCAs). PVA MBs are more stable and offer longer circulation and on-shelf storage time compare to other UCAs. However, the current use as contrast agent is limited only to ultrasound imaging.

    In this project, we fabricated and characterized hybrid contrast agents based on PVA MBs.

    Two methods for developing hybrid contrast agents were proposed. The first method is to combine MBs, currently used as an ultrasound contrast agent, with gold nanoparticles that are used as a preclinical contrast agent for computer tomography (CT). The second method is to determine at which concentration plain MBs suspension has both considerable negative contrast in CT and enhancement of the backscattered signal in ultrasound imaging.

    Both methods were evaluated and optimized. A scenario to achieve promising hybrid contrast agent was described in this report.

  • 193.
    Chen, Zhongze
    KTH, School of Technology and Health (STH), Medical Engineering.
    Assessment of Ultrasound Field Properties and the Potential Effects on Cells2013Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Ultrasound is regarded a convenient and safe tool to acquire diagnostic information that we need for clinical use. For a long time ultrasound has been counted as a harmless method, but after all, there is a heating and a me-chanical impact by ultrasound exposure. This influence can reveal both positive (e.g., cell plant growth) and negative (e.g. cell death) effects. Acoustic exposure pattern changed drastically in recent years due to the rapid, technological developments in ultrasound imaging. Ultrasound imaging has become more sophisticated and new techniques are becoming more common, bringing with them not only increased diagnostic capabilities, but also potential threats as far as safety considerations are concerned. The goal of the thesis project is to analyze the ultrasound field characteristics, based on which research would be achievable in the future about how cells are affected by ultrasound exposure with different basic parameters. These parameters include excitation pressure amplitude, number of cycles in a pulse (n), pulse repetition frequency (PRF), acoustic working frequency (f), phase of ultrasound, shape of ultrasound wave (window mode). Some pilot cell experiments are also done in this project.

    Ultrasound-induced bioeffects on cells have been studied by many scientists, and some experiments tell us that ultrasound beams may cause serious mechanical and thermal damage on e.g. cells. Two general indices, the thermal index (TI) the mechanical index (MI) reflect information on the output level of the ultrasound machine and how a change in output would affect the likelihood of inducing a biological effect. Besides these two indices, other six parameters also are valuable to help us understand the potential threat of ultrasound applications. These parameters are peak negative pressure, peak positive pressure, spatial peak temporal peak intensity (Isptp), spatial peak temporal average intensity (Ispta), spatial peak pulse average intensity (Isppa) and output power of transducer (Wo). The above mentioned eight parameters are important in analyzing the acoustic beams.

    During the first phase of the experiment (acquisition of ultrasound field parameters) a hydrophone was put at the focus point of the ultrasound beam to acquire the time domain waveform signal of the ultrasound waves. By setting up f, PRF, n, phase and window mode into the computer controlled pulser (SNAP system, Ritec Inc), dif-ferent beams were sent to the hydrophone. Different combinations of basic parameters lead to 186 sets of acoustic beams. We used the hydrophone and oscilloscope to record the waveform signal respectively. Then by self-designed MATLAB software (Mathematical Computing Software, MATLAB®, Natick, Massachusetts, United States), the desired eight characteristics of acoustic field were calculated.

    Human chronic myelogenous leukemia cell line (K562) were exposed to defined ultrasound waves in the second phase of the experiment. Both trypan blue and resazurin viability assays were used to evaluate effect on the cells immediately after the exposure and 24 hours after the exposure. Resazurin viability assay conducted immediately after the exposure showed reduction of the cell viability up to 46% when the attenuation of amplitude is 0 dB (i.e. the output is the biggest). No cell death was induced. It also showed that after 24 hours the cells viability partially recovered to about 85%. Trypan blue assay showed nearly no cell death was induced.

  • 194.
    Cheng, Kimberley
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Single-particle cryo-electron microscopy of macromolecular assemblies2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, single-particle cryo-electron microscopy (cryo-EM) was used to study the structure of three macromolecular assemblies: the two hemocyanin isoforms from Rapana thomasiana, the Pyrococcus furiosus chaperonin, and the ribosome from Escherichia coli.

    Hemocyanins are large respiratory proteins in arthropods and molluscs. Most molluscan hemocyanins exist as two distinct isoforms composed of related polypeptides. In most species the two isoforms differ in terms of their oligomeric stability, and thus we set out to investigate the two Rapana thomasiana hemocyanins (RtH) in order to explain this behaviour. Our findings showed that the two RtHio forms are identical at the experimental resolution. Furthermore, three previously unreported connections that most likely contribute to the oligomeric stability were identified.

    Chaperonins are double-ring protein complexes that assist the folding process of nascent, non-native polypeptide chains. The chaperonin from the hyperthermophilic archaea Pyrococcus furiosus belongs to Group II chaperonins, and unlike most othergroup II chaperonins it appears to be homo-oligomeric. The 3D reconstruction of the Pyrococcus furiousus chaperonin revealed a di-octameric structure in a partially closed/open state, something in between the closed folding-active state and the open substrate-accepting state.

    The ribosome is the molecular machine where protein synthesis takes place. In bacteria there is a unique RNA molecule called transfer-messenger RNA (tmRNA) that together with its helper protein SmpB rescues ribosomes trapped on defective messenger RNAs (mRNAs) through a process called trans-translation. tmRNA is about 4 times the size of a normal tRNA, and it is composed of a tRNA-like domain (TLD) that is connected to the mRNA-like domain (MLD) by several pseudoknots (PKs) and RNA helices. During trans-translation, tmRNA utilize its TLD to receive the incomplete polypeptide from the peptidyl-tRNA in the ribosomal P site of the stalledribosome. Subsequently, its MLD is used to tag the incomplete polypeptide with adegradation signal. When tmRNA enters a stalled ribosome the MLD and pseudoknots form a highly structured arc that encircles the beak of the small ribosomal subunit. Byutilizing maximum-likelihood based methods for heterogeneity analysis we could observe the Escherichia coli ribosome in a number of different tmRNA·SmpB-boundstates. The cryo-EM map of the post-accommodated state revealed that the TLD·SmpBpart of the tmRNA·SmpB complex mimics native tRNAs in the A site of stalled ribosomes. The density map also showed that the tmRNA arc remains well structuredand that it is still attached to the beak of the small ribosomal subunit. Thereconstructions of the double-translocation tmRNA-bound ribosome complex showed that the pseudoknots of tmRNA still form an arc, and that they are located at positions similar to the ones assigned for the pseudoknots in the post-accommodated state. In addition, the tmRNA arc exists in two states; one stable and highly structured and another more flexible and disorganized.

  • 195.
    Cheng, Kimberley
    et al.
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Ivanova, Natalia
    Biomedicinskt centrum, Uppsala.
    Scheres, S.H.W
    Pavlov, Michael
    Biomedicinskt centrum.
    Carazo, J.M.
    Herbert, Heinz
    Ehrenberg, Måns
    Lindahl, Martin
    KTH, School of Technology and Health (STH).
    Structural analysis of double translocated tmRNA on the 70S ribosome indicates flexibility of the tmRNA structure.Manuscript (preprint) (Other academic)
  • 196.
    Cheng, Kimberley
    et al.
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Ivanova, Natalia
    Biomedicinskt centrum, Uppsala.
    Scheres, Sjores
    CSIC, Natl Biotechnol Ctr, Biocomp Unit, E-28049 Madrid, Spain .
    Pavlov, Michael Y
    Biomedicinskt centrum, Uppsala.
    Maria Carazo, Jose
    Lund Univ, Mol Biophys KILU.
    Hebert, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Ehrenberg, Måns
    Biomedicinskt centrum, Uppsala.
    Lindahl, Martin
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    tmRNA-SmpB complex mimics native aminoacyl-tRNAs in the A site of stalled ribosomes2010In: Journal of Structural Biology, ISSN 1047-8477, E-ISSN 1095-8657, Vol. 169, no 3, p. 342-348Article in journal (Refereed)
    Abstract [en]

    Bacterial ribosomes stalled on faulty, often truncated, mRNAs lacking stop codons are rescued by trans-translation. It relies on an RNA molecule (tmRNA) capable of replacing the faulty mRNA with its own open reading frame (ORF). Translation of tmRNA ORF results in the tagging of faulty protein for degradation and its release from the ribosome. We used single-particle cryo-electron microscopy to visualize tmRNA together with its helper protein SmpB on the 70S Escherichia coli ribosome in states subsequent to GTP hydrolysis on elongation factor Tu (EF-Tu). Three-dimensional reconstruction and heterogeneity analysis resulted in a 15 A resolution structure of the tmRNA-SmpB complex accommodated in the A site of the ribosome, which shows that SmpB mimics the anticodon- and D-stem of native tRNAs missing in the tRNA-like domain of tmRNA. We conclude that the tmRNA-SmpB complex accommodates in the ribosomal A site very much like an aminoacyl-tRNA during protein elongation. (C) 2009 Elsevier Inc. All rights reserved.

  • 197.
    Cheng, Kimberley
    et al.
    KTH, School of Technology and Health (STH), Structural Biotechnology (Closed 20130701).
    Karlström, M
    Purhonen, P
    Ladenstein, R.
    Herbert, Hans
    Koeck, Philip J.B.
    Low resolution structure and apparent melting temperature of the chaperonin from Pyrococcus furiosusManuscript (preprint) (Other academic)
  • 198.
    Cheng, Kimberley
    et al.
    Department of Biosciences at NOVUM, Karolinska Institutet and School of Technology and Health, Royal Institute of Technology, S-141 57 Huddinge, Sweden.
    Koeck, Philip J. B.
    Department of Biosciences at NOVUM, Karolinska Institutet and School of Technology and Health, Royal Institute of Technology, S-141 57 Huddinge, Sweden.
    Elmund, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Hebert, Hans
    KTH, School of Technology and Health (STH), Structural Biotechnology.
    Ternström, Tomas
    Schwarz, Heinz
    Idakieva, Krassimira
    Parvanova, Katja
    Rapana thomasiana hemocyanin (RtH): Comparison of the two isoforms, RtH1 and RtH2, at 19 Å and 16 Å resolution2006In: Micron, ISSN 0968-4328, E-ISSN 1878-4291, Vol. 37, no 6, p. 566-576Article in journal (Refereed)
    Abstract [en]

    Three-dimensional (3D) reconstructions of the two 8.4 MDa Rapana thomasiana hemocyanin isoforms, RtH1 and RtH2, have been obtained by cryoelectron microscopy of molecules embedded in vitreous ice and single particle image processing. The final 3D structures of the RtH1 and RtH2 didecamers at 19 angstrom and 16 angstrom resolution, respectively, are very similar to earlier reconstructions of gastropodan hemocyanins, revealing structural features such as the obliquely oriented subunits, the five- and two-fold symmetrical axes. Three new interactions are defined; two of them connecting the arch and the wall while the third is formed between the collar and the wall. The collar-wall connection and one of the arch-wall connections are positioned between two individual subunit dimers, while the second arch-wall connection is located between two subunits within the subunit dimer. All three interactions establish connections to the first tier of the wall. Furthermore, for each interaction we have allocated two first tier functional units most likely involved in forming the connections.

  • 199.
    Chowdhury, Manish
    et al.
    KTH, School of Technology and Health (STH).
    Jörgens, Daniel
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    Wang, Chunliang
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization. KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Smedby, Örjan
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    Moreno, Rodrigo
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    Segmentation of Cortical Bone using Fast Level Sets2017In: MEDICAL IMAGING 2017: IMAGE PROCESSING / [ed] Styner, MA Angelini, ED, SPIE - International Society for Optical Engineering, 2017, article id UNSP 1013327Conference paper (Refereed)
    Abstract [en]

    Cortical bone plays a big role in the mechanical competence of bone. The analysis of cortical bone requires accurate segmentation methods. Level set methods are usually in the state-of-the-art for segmenting medical images. However, traditional implementations of this method are computationally expensive. This drawback was recently tackled through the so-called coherent propagation extension of the classical algorithm which has decreased computation times dramatically. In this study, we assess the potential of this technique for segmenting cortical bone in interactive time in 3D images acquired through High Resolution peripheral Quantitative Computed Tomography (HR-pQCT). The obtained segmentations are used to estimate cortical thickness and cortical porosity of the investigated images. Cortical thickness and Cortical porosity is computed using sphere fitting and mathematical morphological operations respectively. Qualitative comparison between the segmentations of our proposed algorithm and a previously published approach on six images volumes reveals superior smoothness properties of the level set approach. While the proposed method yields similar results to previous approaches in regions where the boundary between trabecular and cortical bone is well defined, it yields more stable segmentations in challenging regions. This results in more stable estimation of parameters of cortical bone. The proposed technique takes few seconds to compute, which makes it suitable for clinical settings.

  • 200.
    Chowdhury, Manish
    et al.
    KTH, School of Technology and Health (STH).
    Klintström, Benjamin
    KTH, School of Technology and Health (STH). Linköping University, Sweden.
    Klintström, E.
    Smedby, Örjan
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization. Linköping University, Sweden.
    Moreno, Rodrigo
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Image Processing and Visualization.
    Granulometry-based trabecular bone segmentation2017In: 20th Scandinavian Conference on Image Analysis, SCIA 2017, Springer, 2017, Vol. 10270, p. 100-108Conference paper (Refereed)
    Abstract [en]

    The accuracy of the analyses for studying the three dimensional trabecular bone microstructure rely on the quality of the segmentation between trabecular bone and bone marrow. Such segmentation is challenging for images from computed tomography modalities that can be used in vivo due to their low contrast and resolution. For this purpose, we propose in this paper a granulometry-based segmentation method. In a first step, the trabecular thickness is estimated by using the granulometry in gray scale, which is generated by applying the opening morphological operation with ball-shaped structuring elements of different diameters. This process mimics the traditional sphere-fitting method used for estimating trabecular thickness in segmented images. The residual obtained after computing the granulometry is compared to the original gray scale value in order to obtain a measurement of how likely a voxel belongs to trabecular bone. A threshold is applied to obtain the final segmentation. Six histomorphometric parameters were computed on 14 segmented bone specimens imaged with cone-beam computed tomography (CBCT), considering micro-computed tomography (micro-CT) as the ground truth. Otsu’s thresholding and Automated Region Growing (ARG) segmentation methods were used for comparison. For three parameters (Tb.N, Tb.Th and BV/TV), the proposed segmentation algorithm yielded the highest correlations with micro-CT, while for the remaining three (Tb.Nd, Tb.Tm and Tb.Sp), its performance was comparable to ARG. The method also yielded the strongest average correlation (0.89). When Tb.Th was computed directly from the gray scale images, the correlation was superior to the binary-based methods. The results suggest that the proposed algorithm can be used for studying trabecular bone in vivo through CBCT.

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Output format
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  • asciidoc
  • rtf