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  • 1.
    Abtahi, Farhad
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Aspects of Electrical Bioimpedance Spectrum Estimation2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Electrical bioimpedance spectroscopy (EBIS) has been used to assess the status or composition of various types of tissue, and examples of EBIS include body composition analysis (BCA) and tissue characterisation for skin cancer detection. EBIS is a non-invasive method that has the potential to provide a large amount of information for diagnosis or monitoring purposes, such as the monitoring of pulmonary oedema, i.e., fluid accumulation in the lungs. However, in many cases, systems based on EBIS have not become generally accepted in clinical practice. Possible reasons behind the low acceptance of EBIS could involve inaccurate models; artefacts, such as those from movements; measurement errors; and estimation errors. Previous thoracic EBIS measurements aimed at pulmonary oedema have shown some uncertainties in their results, making it difficult to produce trustworthy monitoring methods. The current research hypothesis was that these uncertainties mostly originate from estimation errors. In particular, time-varying behaviours of the thorax, e.g., respiratory and cardiac activity, can cause estimation errors, which make it tricky to detect the slowly varying behaviour of this system, i.e., pulmonary oedema.

    The aim of this thesis is to investigate potential sources of estimation error in transthoracic impedance spectroscopy (TIS) for pulmonary oedema detection and to propose methods to prevent or compensate for these errors.   This work is mainly focused on two aspects of impedance spectrum estimation: first, the problems associated with the delay between estimations of spectrum samples in the frequency-sweep technique and second, the influence of undersampling (a result of impedance estimation times) when estimating an EBIS spectrum. The delay between frequency sweeps can produce huge errors when analysing EBIS spectra, but its effect decreases with averaging or low-pass filtering, which is a common and simple method for monitoring the time-invariant behaviour of a system. The results show the importance of the undersampling effect as the main estimation error that can cause uncertainty in TIS measurements.  The best time for dealing with this error is during the design process, when the system can be designed to avoid this error or with the possibility to compensate for the error during analysis. A case study of monitoring pulmonary oedema is used to assess the effect of these two estimation errors. However, the results can be generalised to any case for identifying the slowly varying behaviour of physiological systems that also display higher frequency variations.  Finally, some suggestions for designing an EBIS measurement system and analysis methods to avoid or compensate for these estimation errors are discussed.

  • 2.
    Abtahi, Farhad
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Towards Heart Rate Variability Tools in P-Health: Pervasive, Preventive, Predictive and Personalized2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Heart rate variability (HRV) has received much attention lately. It has been shown that HRV can be used to monitor the autonomic nervous system and to detect autonomic dysfunction, especially vagal dysfunction. Reduced HRV is associated with several diseases and has also been suggested as a predictor of poor outcomes and sudden cardiac death. HRV is, however, not yet widely accepted as a clinical tool and is mostly used for research. Advances in neuroimmunity with an improved understanding of the link between the nervous and immune systems have opened a new potential arena for HRV applications. An example is when systemic inflammation and autoimmune disease are primarily caused by low vagal activity; it can be detected and prognosticated by reduced HRV. This thesis is the result of several technical development steps and exploratory research where HRV is applied as a prognostic diagnostic tool with preventive potential. The main objectives were 1) to develop an affordable tool for the effective analysis of HRV, 2) to study the correlation between HRV and pro-inflammatory markers and the potential degree of activity in the cholinergic anti-inflammatory pathway, and 3) to develop a biofeedback application intended for support of personal capability to increase the vagal activity as reflected in increased HRV. Written as a compilation thesis, the methodology and the results of each study are presented in each appended paper. In the thesis frame/summary chapter, a summary of each of the included papers is presented, grouped by topic and with their connections. The summary of the results shows that the developed tools may accurately register and properly analyse and potentially influence HRV through the designed biofeedback game. HRV can be used as a prognostic tool, not just in traditional healthcare with a focus on illness but also in wellness. By using these tools for the early detection of decreased HRV, prompt intervention may be possible, enabling the prevention of disease. Gamification and serious gaming is a potential platform to motivate people to follow a routine of exercise that might, through biofeedback, improve HRV and thereby health.

  • 3.
    Abtahi, Farhad
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Karolinska Institutet, Sweden.
    Hilderman, Marie
    Bruchfeld, Annette
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. University of Borås, Sweden.
    Janerot-Sjöberg, Birgitta
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging. Karolinska Institutet, Sweden.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Karolinska Institutet, Sweden.
    Pro-inflammatory Blood Markers and Heart Rate Variability in Apnoea as a Reflection of Basal Vagal ToneManuscript (preprint) (Other academic)
    Abstract [en]

    Pro-inflammatory cytokines play a crucial role in inflammatory response, which istightly regulated by the nervous system to avoid the damage caused by inflammation. There isevidence for a cholinergic anti-inflammatory pathway that includes afferent and efferent vagalnerves that sense the inflammation and stimulate the anti-inflammatory response. Non-functionalanti-inflammatory response might lead to excessive and chronic inflammation e.g., rheumatoidarthritis (RA), inflammatory bowel disease (IBD), and poor outcome. Heart rate variability(HRV) has been proposed as a potential tool to monitor the level of anti-inflammatory activitythrough the monitoring of vagal activity. In this paper, the association of pro-inflammatorymarkers with HRV indices is evaluated. We used a database called “Heart Biomarker Evaluationin Apnea Treatment (HeartBEAT)” that consists of 6±2 hours of Electrocardiogram (ECG)recordings during nocturnal sleep from 318 patients at baseline and 301of them at 3 monthsfollow-up. HRV indices are calculated from ECG recordings of 5-360 minutes. The results showa statistically significant correlation between heart rate (HR) and pro-inflammatory cytokines,independent of duration of ECG analysis. HRV indices e.g., standard deviation of all RRintervals (SDNN) show an inverse relation to the pro-inflammatory cytokines. Longer ECGrecordings show a higher potential to reflect the level of anti-inflammatory response. In light oftheories for the cholinergic anti-inflammatory pathway, a combination of HR and HRV as areflection of basal vagal activity might be a potential prognostic tool for interventional guidance.

  • 4.
    Abtahi, Farhad
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Ji, Guangchao
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Lu, Ke
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Rödby, Kristian
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Björlin, Anders
    Kiwok AB.
    Östlund, Anders
    Kiwok AB.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Högskolan i Borås, Akademin för vård, arbetsliv och välfärd.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Textile-Electronic Integration in Wearable Measurement Garments for Pervasive Healthcare Monitoring2015Conference paper (Other academic)
  • 5.
    Abtahi, Farhad
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Lu, Ke
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Dizon, M
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Johansson, M
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Högskolan i Borås, Akademin för vård, arbetsliv och välfärd.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Evaluation of Atrial Fibrillation Detection by using Heart Rate Variability analysis2015Conference paper (Other academic)
  • 6.
    Abtahi, Farhad
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Lu, Ke
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Guangchao, Li
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Rödby, Kristian
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Högskolan i Borås.
    A Knitted Garment using Intarsia Technique for Heart Rate Variability Biofeedback: Evaluation of Initial Prototype.2015Conference paper (Other academic)
  • 7.
    Ahlstrom, Linda
    et al.
    Högskolan Borås.
    Larsson Fallman, Sara
    Högskolan Borås.
    Dellve, Lotta
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics. Public Health and Community Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Return to work from long-term sick leave: a five-year prospective study of the importance of adjustment latitudes at work and home2014Conference paper (Other academic)
    Abstract [en]

    Background

    Adjustment latitude among employees, i.e. adjusting work to individual’s health capacity, has been associated with successful return to work (RTW) in cross-sectional studies. The aim is to investigate the long-term importance of adjustment latitude at the workplace and at home, as well as attitudes (own and colleagues) for increased work ability (WA), working degree (WD) and health-related quality of life (HRQoL) among female human service workers (HSW) on long-term sick leave in Sweden.

    Methods

    A cohort of female HSW (n=324) on long-term sick leave (>60 day) received a questionnaire at four times (0, 6, 12, 60 months). Prevalence ratios (PR) were used to examine possible relationships between explanatory factors and outcomes. Linear mixed models were used for longitudinal analysis of the repeated measurements of WA Score (0-10), WD (0-100%) and HRQoL (0-100). Analyses were performed with different models; the explanatory variables for each model were adjustment latitude, attitudes towards breaks at work, shared or single household and amount of household work.

    Result

    Having more adjustment latitude at work was associated with both increased WA and RTW compared to having few adjustment latitude opportunities. Adjustments related to working-pace were strongly associated with increased WD (PR 3.29(95%CI=1.71-6.26)), as were adjustments to working-place. Having opportunities to take short breaks at work, and a general acceptance at work to take short breaks was associated with increased WA. At home, a higher responsibility for household work (PR 1.98(95%CI=1.33-2.95)) was related to increased WA and RTW. Individuals with possibilities for adjustment latitude, especially pace and place, at work, and an acceptance to take breaks at work, increased in WA score significantly more over time and had higher WA score compared with individuals not having such opportunities at work. These prospective results were similar for the outcome WD and HRQoL.

    Conclusions

    The results highlight the importance of possibilities for adjustment latitude at work and at home, as well as accepting attitudes to take short breaks to increase WA and RTW among female human service workers previously on long-term sick leave.

  • 8.
    Akay, Altug
    KTH, School of Technology and Health (STH), Health Systems Engineering, Systems Safety and Management.
    A Novel Method to Intelligently Mine Social Media to Assess Consumer Sentiment of Pharmaceutical Drugs2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis focuses on the development of novel data mining techniques that convert user interactions in social media networks into readable data that would benefit users, companies, and governments. The readable data can either warn of dangerous side effects of pharmaceutical drugs or improve intervention strategies. A weighted model enabled us to represent user activity in the network, that allowed us to reflect user sentiment of a pharmaceutical drug and/or service. The result is an accurate representation of user sentiment. This approach, when modified for specific diseases, drugs, and services, can enable rapid user feedback that can be converted into rapid responses from consumers to industry and government to withdraw possibly dangerous drugs and services from the market or improve said drugs and services.

    Our approach monitors social media networks in real-time, enabling government and industry to rapidly respond to consumer sentiment of pharmaceutical drugs and services.

  • 9.
    Andersson, Karin
    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.
    Lean Projects and Sustainability in the Swedish Agricultural Sector2013Conference paper (Other academic)
  • 10.
    Antoni, Per
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hed, Yvonne
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Nordberg, Axel
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Nyström, Daniel
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Malkoch, Michael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    One-pot dendritic growth and post-functionalization of multifunctional dendrimers: Synthesis and application2009Manuscript (preprint) (Other academic)
  • 11.
    Antonsson Lundberg, Ann-Beth
    KTH, School of Technology and Health (STH), Ergonomics.
    A systems analysis of a target group of enterprises: A new way forward for the dissemination of research results and sustainable technologies2006Conference paper (Other academic)
  • 12.
    Antonsson Lundberg, Ann-Beth
    KTH, School of Technology and Health (STH), Ergonomics.
    An interactive Internet tool supporting risk management in SMEs: The Chemical Guide (KemiGuiden)2005Conference paper (Other academic)
  • 13.
    Antonsson Lundberg, Ann-Beth
    KTH, School of Technology and Health (STH), Ergonomics.
    Improving work environment in small enterprises: The need for a holistic perspective and adaptation to small enterprise reality2007Conference paper (Other academic)
  • 14.
    Antonsson Lundberg, Ann-Beth
    KTH, School of Technology and Health (STH), Ergonomics.
    Risk assessment tools for small enterprises: evaluation of uptake and effect2009In: USE 2009: Programme and abstract book, 2009, 118-118 p.Conference paper (Other academic)
    Abstract [en]

    Background: Risk assessment is a core component in the management of the working environment. Risk assessment helps identify and prioritize risks and reduce risks through implementation of control measures. Aim: To evaluate how tools for risk assessment are used by small enterprises and what the result is from using the tools. Method: Randomly selected small enterprises in printing and electroplating industry were contacted and asked to participate in an evaluation of tools for chemical risk assessment developed to suit small enterprises. An initial interview was made with the enterprises accepting to participate in the testing, aiming at surveying how they use to assess chemical risks. The enterprises were provided with one out of six tools. Ten enterprises in each sector were asked to test each tool, adding up to 20 enterprises testing each tool. After three and six months the enterprise was contacted. If they had tested the tool, a new interview was made, exploring their opinion on the tool and their experiences from using it. Enterprises not having tested the tools were also interviewed about the reasons why they did not use the tool they were provided. In enterprises having used the tools, an expert risk assessment was made and compared to the risk assessment of the enterprise in order to evaluate the quality of the risk assessment tool and the enterprise's use of it. Result: More than 60 % of the enterprises accepted to test the tools, reflecting an interest and concern for chemical risks in their work environment. The follow-up interviews are currently conducted and will be finished during April 2009. The results show how risk assessment works in practice in small enterprises. The study has revealed several problems with different tools and some unexpected results. One example is that several enterprises have concluded that they are content with their old method for risk assessment, which was using safety data sheets, reflecting a profound lack of understanding of what risk assessment is about. Results from the evaluation will be presented, showing how small enterprises perceive the different kinds of tools tested and what the outcomes in terms of quality are of the tested tools. The results will be discussed in relation to the enterprises and their previous experience of and knowledge about risk assessment.

  • 15.
    Antonsson Lundberg, Ann-Beth
    KTH, School of Technology and Health (STH), Ergonomics.
    Risk management in small enterprises: A system analysis of what works and what doesn´t2006Conference paper (Other academic)
  • 16.
    Antonsson Lundberg, Ann-Beth
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics. IVL Svenska Miljöinstitutet AB.
    Hasle, Peter
    Aalborg Universitet.
    How can the context affect what strategies are effective in improving the working environment in small companies?2015Conference paper (Other academic)
  • 17.
    Antonsson Lundberg, Ann-Beth
    et al.
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics. IVL Svenska Miljöinstitutet AB.
    Hasle, Peter
    Aalborg Universitet.
    What kind of knowledge do small companies need to improve their working environment?2015Conference paper (Other academic)
  • 18.
    Antonsson Lundberg, Ann-Beth
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Nyman, Teresia
    KI, Institutionen för folkhälsovetenskap.
    Education for Occupational health service professionals in different countries2011Conference paper (Other academic)
  • 19.
    Antonsson Lundberg, Ann-Beth
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Schmidt, L
    Swedish Occupational Health Services and Small Enterprises: How does it work?2005In: OHS2005 Conference Proceedings: SJWEH Supplements 2005; no 1, 2005Conference paper (Other academic)
  • 20. Arman, Rebecka
    et al.
    Wikström, Ewa
    Tengelin, Ellinor
    Dellve, Lotta
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Work activities and stress among managers in health care2012In: The Work of Managers: Towards a Practice Theory of Management / [ed] Tengblad, Sten, Oxford: Oxford University Press, 2012, 1Chapter in book (Other academic)
    Abstract [en]

    This chapter reports on the work activities, time-use patterns, and stress patterns of ten health care managers in Sweden. The qualitative and quantitative evidence reveals the fragmentation in their nine-hour working days where each activity, on average, lasts only ten minutes. The time-use patterns vary individually though some patterns are related to position and unit type. Activities deal with the coexisting and competing logics of employeeship, administration, and strategy and risk handling. None of the managers’ approaches for handling the multiple legitimation processes and delimiting their workload boundaries really challenges the complexity of the coexistence of the multiple logics or the boundlessness of their working hours. Using biophysical measures, the research finds that stress reported by the managers is caused by (a) interruptions during challenging tasks and (b) personal situations such as private dilemmas and conflict-loaded or ineffective meetings. It is important to acknowledge managers’ fragmented working situation and to recognize that management should be seen as collective process, or as part of an administrative system.

  • 21.
    Aronson, Eran
    KTH, School of Technology and Health (STH), Design, Work Environment, Safety and Health, DASH.
    Research Project: Lighting Häggvik Tunnel, Sollentuna2013Report (Other academic)
    Abstract [en]

    A reserch paper investigating the posibility of lowering light levels in tunnel while using LED's. Done with and for Trafikverket as part of an ongoing research regarding tunnel lighting.

  • 22.
    Aronson, Eran
    KTH, School of Technology and Health (STH).
    Visual adaptation for tunnel entrance2013Report (Other academic)
    Abstract [en]

    A research report done by the lighting laboratory at KTH STH for Trafikverket. The report is presenting a second stage of tunnel lighting research, focusing on the tunnel entrance zone, where improvements to existing recommendations are suggested.

  • 23. Aronsson, Gunnar
    et al.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    Randle, Hanne
    Svensson, Lennart
    Inte bara här och nu utan också där och då: Reflektioner om arbetslivsforskningen och det stora hållbarhetsprojektet2009In: Arbetslivsforskning och hållbarhet: Arbetsliv i omvandling / [ed] I: Porsfelt, Växjö: Växjö universitet , 2009, 1Chapter in book (Other academic)
  • 24.
    Aronsson, K
    et al.
    Karolinska Institutet.
    Teär Fahnhjelm, K
    Karolinska Institutet.
    Nylén, P
    KTH, School of Technology and Health (STH), Ergonomics.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    Visual ergonomics and eye strain in eye careprofessionals2012In: NES2012 Proceedings: Ergonomics for sustainability and growth / [ed] Ann-Beth Antonsson, Göran M Hägg, 2012Conference paper (Other academic)
    Abstract [en]

    Eye care professionals spend many hours a day in darkness performing visually demanding tasks. A new eye hospital will be built in Stockholm 2018. The current lighting, logistics, and working conditions are analysed in a multidisciplinary project aiming to optimise settings in the new hospital. The main purpose of the present project was to study visual ergonomics and current eye strain in employees at an eye hospital. Ninety-six employees answered a validated questionnaire regarding their experiences of light, visual ergonomics and eye strain problems. Twenty-three radiologists and 14 paediatricians at a university hospital were used as comparison groups. Eye strain was common in all departments at the hospital but was significantly more common only among radiologists compared to paediatricians. Overall, women experienced significantly more eye strain than men.

  • 25.
    Asplund, Maria
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Conjugated Polymers for Neural Interfaces: Prospects, possibilities and future challenges2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Within the field of neuroprosthetics the possibility to use implanted electrodes for communication with the nervous system is explored. Much effort is put into the material aspects of the electrode implant to increase charge injection capacity, suppress foreign body response and build micro sized electrode arrays allowing close contact with neurons. Conducting polymers, in particular poly(3,4-ethylene dioxythiophene) (PEDOT), have been suggested as materials highly interesting for such neural communication electrodes. The possibility to tailor the material both mechanically and biochemically to suit specific applications, is a substantial benefit with polymers when compared to metals. PEDOT also have hybrid charge transfer properties, including both electronic and ionic conduction, which allow for highly efficient charge injection.

     

    Part of this thesis describes a method of tailoring PEDOT through exchanging the counter ion used in electropolymerisation process. Commonly used surfactants can thereby be excluded and instead, different biomolecules can be incorporated into the polymer. The electrochemical characteristics of the polymer film depend on the ion. PEDOT electropolymerised with heparin was here determined to have the most advantageous properties. In vitro methods were applied to confirm non-cytotoxicity of the formed PEDOT:biomolecular composites. In addition, biocompatibility was affirmed for PEDOT:heparin by evaluation of inflammatory response and neuron density when implanted in rodent cortex.

     

    One advantage with PEDOT often stated, is its high stability compared to other conducting polymers. A battery of tests simulating the biological environment was therefore applied to investigate this stability, and especially the influence of the incorporated heparin. These tests showed that there was a decline in the electroactivity of PEDOT over time. This also applied in phosphate buffered saline at body temperature and in the absence of other stressors. The time course of degradation also differed depending on whether the counter ion was the surfactant polystyrene sulphonate or heparin, with a slightly better stability for the former.

     

    One possibility with PEDOT, often overlooked for biological applications, is the use of its semi conducting properties in order to include logic functions in the implant. This thesis presents the concept of using PEDOT electrochemical transistors to construct textile electrode arrays with in-built multiplexing. Using the electrolyte mediated interaction between adjacent PEDOT coated fibres to switch the polymer coat between conducting and non conducting states, then transistor function can be included in the conducting textile. Analogue circuit simulations based on experimentally found transistor characteristics proved the feasibility of these textile arrays. Developments of better polymer coatings, electrolytes and encapsulation techniques for this technology, were also identified to be essential steps in order to make these devices truly useful.

     

    In summary, this work shows the potential of PEDOT to improve neural interfaces in several ways. Some weaknesses of the polymer and the polymer electronics are presented and this, together with the epidemiological data, should point in the direction for future studies within this field.

  • 26.
    Atefi, Seyed Reza
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Electrical Bioimpedance Cerebral Monitoring: From Hypothesis and Simulation to First Experimental Evidence in Stroke Patients2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Stroke is amongthe leading causes of death worldwide and requires immediate care to prevent death or permanent disability. Unfortunately, the current stateof stroke diagnosis is limited to fixed neuroimaging facilities that do not allow rapid stroke diagnosis. Hence, a portable stroke-diagnosis device could assist in the pre-hospital triage of patients. Moreover, such a portable device could also be useful for bedside stroke monitoring of patients in the Neuro Intensive Care Unit (Neuro-ICU) to avoid unnecessary neuroimaging. Recent animal studies and numerical simulations have supported the idea of implementing Electrical Bioimpedance (EBI) in a portable device, allowing non-invasive assessment as a useful tool for the pre-hospital triage of stroke and Traumatic Brain Injury (TBI) patients. Unfortunately, these studies have not reported any results from human subjects in the acute phase of the stroke. The numerical simulations are also based on simple models that sometimes lack necessary details.

    Finite Element Method (FEM) simulations on a realistic numerical head model as well as experimental Bioimpedance Spectroscopy (BIS) measurements from human subjectsin the acute, subacute and chronic phasesof stroke were used to answer the following research questions: (i) Does stroke modify the electrical properties of brain tissue in a way that is detectable via EBI? (ii) Would it be possible to detect stroke via EBI as early as in the acute and sub-acute phase?(iii) Is EBI sensitive enough to monitor changes caused by stroke pathogenesis?

    Using FEM to simulate electrical current injection on the head and study the resulting distribution of electrical potential on the scalp, it was shown that Intra-Cranial Hemorrhage (ICH) affects the quasi-symmetric scalp potential distribution,creating larger left-right potential asymmetry when compared to the healthy head model. Proof-of-concept FEM simulations were also tested in a small cohort of 6ICH patients and 10 healthy controls, showing that the left-right potential difference in the patients is significantly (p<0.05) larger than in the controls. Using bioimpedance measurements in the acute,  subacute and chronic phasesof stroke and examining simple features, it was also shown that the head EBI measurements of patients suffering stroke are different from controls, enabling the discrimination of healthy controls and stroke patients at any stage of the stroke. The absolute change in test-retest resistance measurements of the control group (~5.33%) was also found to be significantly (p<0.05) smaller than the EBI measurements of patients obtained 24 hours and 72 hours after stroke onset (20.44%). These results suggested that scalp EBI is sensitive to stroke pathogenesis changesand thususeful for bedside monitoring in the Neuro-ICU. These results suggested that EBI is a potentially useful tool for stroke diagnosis and monitoring.

    Finally, the initial observations based on a small number of patients, addressing the proposed future work of this thesis, suggested that the average head resistance amplitude of hemorrhagic stroke patients is smaller than in healthy controls, while ischemic stroke patients show a larger resistance amplitude than the controls. Scalp potential asymmetry analysis of healthy, hemorrhagic and ischemic stroke subjects also suggests that these three groups can be separated. However, these results are based on a small number of patients and need to be validated using a larger cohort. Initial observations also showed that the resistance of the EBI measurements of controls is robust between test and retest measurements, showing no significant difference (less than 2% and p>0.05). Subject position during EBI recording (supine or sitting) did not seem to affect the resistance of the EBI measurements (p>0.05). However, age, sex and head size showed significant effects on the resistance measurements. These initial observations are encouraging for further research on EBI for cerebral monitoring and stroke diagnosis. However, at this stage, considering the uncertainties in stroke type differentiation, EBI cannot replace CT but has the potential to be used as a consultation tool.

  • 27.
    Atefi, Seyed Reza
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Tomner, Jens
    Kostulas, Konstantinos
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Bonmassar, Giorgio
    Stroke Pathogenesis Alters Dielectric Properties of Brain Tissue Supporting Electrical Bioimpedance Technology as a tool for Cerebral MonitoringManuscript (preprint) (Other academic)
  • 28.
    Ayas, Ebru
    KTH, School of Technology and Health (STH), Ergonomics.
    Engineering Quality Feelings: Applications in products, service environments and work systems2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Contemporary quality issues in product design are moving from materialistic to emotional user fulfillment; comprehensive research is needed to examine quality product feelings. This research is directed toward a deeper understanding of user and customer quality feelings for different product types, including services.

    The quality feelings concept includes dimensions of product quality, especially functionality, ergonomics and aesthetics. The first objective of this thesis is to identify, prioritize and synthesize quality feelings into product attributes in product development applications. The second objective is to explore, test and propose methodological approaches for designing quality feelings into products.

    Several methods from psychology, ergonomics, statistics and probabilistic methods and heuristics were applied to achieve the objectives. From a methodological viewpoint, Likert scales, free elicitation technique and Just About Right scales were applied for data collection. Multiple Regression, Factor Analysis, Correspondence Analysis, Genetic algorithms, Partial Least Squares (PLS) and Rough Sets (RS) were applied for data analyses. For ergonomic product evaluations, direct observations, 3D workload simulations, time and frequency analyses were conducted.

    Five product applications are included in this thesis: operator driver cabin design of reach trucks, steering wheel design trigger switch design in right-angled nutrunners, bed-making systemsproducts and waiting room environments.

    Heuristic methods were found effective when there is a high number of product attributes that interact to provide quality feelings. RS results are consistent with PLS attribute predictions. When the number of product attributes is large in comparison to the number of observations, PLS extracts informative results for quality feelings. The RS method is effective in identifying interactions among design attributes.

    Quality feelings are associated with both tangible (tactile characteristics) and intangible (quick and easy to use) product characteristics. Words such as safety, functionality, ergonomics, comfort, reliability, supportiveness, usability, feedback, pleasantness, attractiveness, durability and distinctiveness describe quality feelings from tangible products and services. Based on product type, the quality dimensions represented by these words possess different interactions and dependencies. In work environments, products act as prostheses between workers for social interaction, which need to be considered as important quality feelings dimensions.

  • 29.
    Ayas, Ebru
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    An Affective Engineering Assessment of a Hospital Bedding System Innovation2011In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126Article in journal (Other academic)
    Abstract [en]

    Developing bedding products requires consideration of human-product interactions such as usability and quality aspects besides ergonomics and productivity. Previous studies focus on finding associations between discomfort evaluations and physiological measurements of conventional bedding. The purpose of this study is to assess a new bedding system by observing affective and discomfort perceptions, physical loads, and time usage by nursing personnel. Fourteen nursese valuated a conventional and a new bedding system. Results suggest that nurses’ quality perceptions and overall experiences with the new bedding were positive. Considering physical loads the average time and frequency of bending forward were significantly lower for the new bedding versus conventional bedding. The time analysis yielded significant improvements to make a bed with the new bedmaking system. Quality perceptions were associated with tactile qualities (e.g. soft, nice to touch, etc.) and applicability (e.g. quick setup) for both bedmaking systems.

  • 30.
    Ayas, Ebru
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Eklund, Jörgen
    KTH, School of Technology and Health (STH), Ergonomics.
    Ishihara, Shigekazu
    Affective engineering evaluation of non-linear trigger switch mechanisms2011In: Applied Ergonomics, ISSN 0003-6870, E-ISSN 1872-9126Article in journal (Other academic)
    Abstract [en]

    The trigger switch mechanisms of nutrunners are important for operators to perceive feedback while tightening bolt joints. Previous studies focus on associations between discomfort evaluations and powered tool operation. This paper addresses how operator preferences are linked with functionality requirements from trigger switch mechanisms. Subjects evaluated five switch mechanism prototypes regarding perceptions of quality, feedback, firmness, and distinctness. Results suggest that loading and unloading phases of trigger operation are significant predictors of perceptions of quality. The trigger switch mechanism with a combination of high peak-drop-bottom forces was perceived with better quality, feedback, and distinctness in comparison to the other mechanisms. The study also revealed that when the switch mechanism was designed to give more distinctness and feedback, higher quality is perceived.

  • 31.
    Bengt, Halling
    KTH, School of Technology and Health (STH), Health Systems Engineering, Ergonomics.
    Lean Implementation: the significance of people and dualism2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Lean, with its origins at the Toyota Motor Company, is a concept that is known to increase effectiveness in manufacturing. The Lean concept is now argued to be relevant not only in manufacturing but in service and health-care delivery as well. The reported results of Lean implementation efforts are divided. There are reports that most of the Lean implementation efforts are not reaching the goal; on the other hand, there are reports of promising results. The divided results from Lean implementation efforts show how important it is to research and identify factors that are barriers to successful implementation of Lean. This thesis aims to contribute knowledge about barriers to Lean implementation by collecting empirical findings from manufacturing and health care and structuring the perceived barriers and difficulties to Lean implementation. My first study aimed to compare similarities and divergences in barriers to Lean described by key informants in manufacturing and health care. The data was collected via semi-structured interviews. Findings showed that the perceived difficulties and barriers are much the same in manufacturing and health care. The second study was a case study at a manufacturing firm, researching how the views on Lean of the managers implementing Lean influence its implementation. Data was collected via semi-structured interviews with 20 individuals and covered all hierarchical management levels in the company. Findings showed that managers' views on Lean influence the implementation but also that learning during the implementation process can alter managers' views of Lean. The third study aimed to research how management of Lean is described in the literature. This was done through a literature review. The findings showed that Lean management is a matter of dualism, consisting of two complementary systems of action, management and leadership, which are related to the two basic principles of Lean, continuous improvement and respect for the people.

  • 32.
    Bergholm, Fredrik
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Hamid Muhammed, Hamed
    KTH, School of Technology and Health (STH), Medical Engineering.
    Larsolle, A.
    Acquiring instantaneous multispectral imagery using a single image sensor with multiple filter mosaic2007Conference paper (Other academic)
  • 33.
    Berglund, Martina
    KTH, School of Technology and Health (STH), Ergonomics.
    Using Tentacles in Planning and Scheduling Work: Activities, Roles and Contributions2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Handling production scheduling is increasingly difficult for manyenterprises, and human involvement is necessary. The overall objective ofthis research was to gain further understanding of planners’ and schedulers’work within the manufacturing industry, to elucidate how their worksituation is formed, and to explain their significance to other employees’work and company activities. Scheduling work was studied in fourcompanies in the Swedish woodworking industry; a sawmill, a parquet floormanufacturer, a furniture manufacturer and a house manufacturer. Themethod used was activity analysis which is based on the analysis of workactivities in real work situations. Data collection included 20 days’observations and 65 interviews. Cross-case analysis with British cases onplanning work was also included.The findings revealed that the schedulers’ tasks lead to many activities. Twothirds of these are what can be expected. The remaining third constitutesactivities that depend on the schedulers’ individual attributes and the contextin which they work. The schedulers serve as problem solvers in a number ofdomains and constitute efficient information nodes, making them animportant service function. Furthermore, they have an alignment rolebetween different organizational groups. This role is specifically remarkablein dealing with production enquiries that must be aligned with productioncapability. Here, both planners and schedulers play an essential role inlinking the manufacturing and the commercial sides and their differentfunctional logics.Planners and schedulers in daily work exert strong influence on others. Theydo not hold legitimate power. Instead their influence emanates mainly fromaccess to and control of information and their ability to apply expertise tointerpret this information and examine the impact of decisions made acrossdifferent areas of the business. Personal power related to social skills is alsosignificant.Furthermore, they facilitate others’ work in continuous personalinteractions, serving the technical scheduling software system, and aligningdifferent organizational functions. In combination with expert knowledgeand developed social skills, they significantly contribute to quality operationsperformance. Finally, the schedulers influence the decision latitude of otheremployees and may indirectly promote job satisfaction, thus contributing todeveloping appropriate working conditions for others in the company.

  • 34.
    Berglund, Martina
    et al.
    KTH, School of Technology and Health (STH), Ergonomics.
    Guinery, Jane
    Production planning aligning customer requests with production capabilityManuscript (preprint) (Other academic)
  • 35.
    Bjällmark, Anna
    KTH, School of Technology and Health (STH), Medical Engineering.
    New ultrasonographic approaches to monitoring cardiac and vascular function2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Atherosclerotic cardiovascular disease is the leading cause of death worldwide. To decrease mortality and morbidity in cardiovascular disease, the development of accurate, non-invasive methods for early diagnosis of atherosclerotic cardiac and vascular engagement is of considerable clinical interest. Cardiovascular ultrasound imaging is today the cornerstone in the routine evaluation of cardiovascular function and recent development has resulted in two new techniques, tissue velocity imaging (TVI) and speckle tracking, which allow objective quantification of cardiovascular function. TVI and speckle tracking are the basis for three new approaches to cardiac and vascular monitoring presented in this thesis: wave intensity wall analysis (WIWA), two-dimensional strain imaging in the common carotid artery, and the state diagram of the heart.

     

    WIWA uses longitudinal and radial strain rate as input for calculations of wave intensity in the arterial wall. In this thesis, WIWA was validated against a commercially available wave intensity system, showing that speckle tracking-derived strain variables can be useful in wave intensity analysis. WIWA was further tested in patients with end stage renal disease and documented high mortality in cardiovascular disease. The latter study evaluated the effects of a single session of hemodialysis using WIWA and TVI variables and showed improved systolic function after hemodialysis. The results also indicated that preload-adjusted early systolic wave intensity obtained by the WIWA system may contribute in the assessment of left ventricular contractility in this patient category. Two-dimensional strain imaging in the common carotid artery is a new approach showing great potential to detect age-dependent differences in mechanical properties of the common carotid artery. Among the measured strain variables, global circumferential strain had the best discriminating performance and appeared to be superior to conventional measures of arterial stiffness such as elastic modulus and β stiffness index. The state diagram is a visualisation tool that provides a quantitative overview of the temporal interrelationship of mechanical events in the left and right ventricles. Case examples and a small clinical study showed that state diagrams clearly visualize cardiac function and can be useful in the detection of non ST-elevation myocardial infarction (NSTEMI).

     

    Even though WIWA, two-dimensional strain imaging in the common carotid artery and the state diagram show potential to be useful in the evaluation of cardiovascular function, there still remains a considerable amount of work to be done before they can be used in the daily clinical practice.

  • 36. Blogg, L
    et al.
    Gennser, Mikael
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Arterial bubbles following trimix dives2014Conference paper (Other academic)
  • 37. Borosund, Elin
    et al.
    Cvancarova, Milada
    Moore, Shirley M.
    Ekstedt, Mirjam
    KTH, School of Technology and Health (STH), Health Systems Engineering, Systems Safety and Management.
    Ruland, Cornelia M.
    Preliminary Results Of Two Web-Based Interventions On Symptom Distress, Anxiety And Depression Among Breast Cancer Patients2014In: Annals of Behavioral Medicine, ISSN 0883-6612, E-ISSN 1532-4796, Vol. 47, S188-S188 p.Article in journal (Other academic)
  • 38.
    Broome, Michael
    KTH, School of Technology and Health (STH), Medical Engineering.
    Aplysia CorVascSim2012Other (Other academic)
  • 39.
    Broomé, Michael
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging. Karolinska Univ Hosp, Sweden.
    Scarce resources call for us to weigh the pros and cons of every single decision2016In: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 105, no 8, 880-880 p.Article in journal (Other academic)
  • 40.
    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.

  • 41.
    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)
  • 42.
    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.

  • 43.
    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.

  • 44.
    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)
  • 45.
    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)
  • 46. Ciuha, U
    et al.
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology. KTH, School of Technology and Health (STH), Centres, Swedish Aerospace Physiology Centre, SAPC.
    Mekjavic, I.B.
    PlanHab: The effect of hypoxic bedrest on behavioural temperature regulation2014In: Proceedings from 35th Annual International Gravitational Physiology Meeting, 2014Conference paper (Other academic)
  • 47. Ciuha, U
    et al.
    Eiken, Ola
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Mekjavic, I.B.
    Grönkvist, Mikael
    KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
    Strategies for increasing evaporative cooling during simulated desert patrol missions2014In: Proceedings from 3rd International Congress on Soldiers Physical Performance, 2014Conference paper (Other academic)
  • 48.
    Colarieti-Tosti, Massimiliano
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Brooks, M. S. S.
    Eriksson, O.
    Approximate Molecular and Crystal Field Excitation Energies Derived from Density Functional TheoryManuscript (preprint) (Other academic)
  • 49.
    Dahlgren, Anna
    et al.
    KTH, School of Technology and Health (STH), Patientsäkerhet.
    Van Leeuwen, W.
    Kircher, A.
    Lutzhoft, M.
    Barnett, M.
    Kecklund, G.
    Akerstedt, T.
    Sleep and fatigue in bridge officers working 6 h on and 6 h off - a simulator study2012In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 21, 331-331 p.Article in journal (Other academic)
  • 50.
    Danielsson, Christina
    KTH, School of Technology and Health (STH), Design, Work Environment, Safety and Health, DASH.
    Office Environment and Employee Satisfaction: The Impact of Office-type.Manuscript (Other academic)
1234567 1 - 50 of 306
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