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  • 101.
    Kwon, H.
    et al.
    Yonsei Univ, Coll Sci & Technol, Wonju 26493, South Korea..
    Rojas, Cristian
    KTH, School of Electrical Engineering and Computer Science (EECS), Automatic Control.
    Rutkove, S. B.
    Harvard Med Sch, Beth Israel Deaconess Med Ctr, Dept Neurol, Boston, MA 02215 USA..
    Sanchez, B.
    Harvard Med Sch, Beth Israel Deaconess Med Ctr, Dept Neurol, Boston, MA 02215 USA..
    Three-harmonic optimal multisine input power spectrum for bioimpedance identification2019In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 40, no 5, article id 05NT02Article in journal (Refereed)
    Abstract [en]

    Objective: The attention towards optimal signals for measuring electrical bioimpedance (EBI) has increased recently due to the many advantages they offer such as, for example, reduced measuring time. Here, the design of a three-harmonic optimized multisine input power spectrum for measuring bioimpedance is considered. Approach: The approach is based on designing the input power spectrum multisine excitation by optimizing a scalar function of the information matrix using the Fricke-Morse model. Main results: Simple analytical equations are provided that can be adopted by the reader to optimize the multisine input power spectrum to satisfy any specific application-related EBI measurement. Significance: The presented signal may be a good choice of excitation signal in EBI applications where optimal excitation power spectrum is desired.

  • 102.
    Ladhani, Laila
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Pardon, Gaspard
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Meeuws, Hanne
    Janssen Diagnostics.
    van Wesenbeeck, Liesbeth
    Janssen Diagnostics.
    Schmidt, Kristiane
    Janssen Diagnostics.
    Stuyver, Lieven
    Janssen Diagnostics .
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Sampling and detection of airborne influenza virus towards point-of-care applications2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, PlosONEArticle in journal (Refereed)
    Abstract [en]

    Airborne transmission of the influenza virus contributes significantly to the spread of this infectious pathogen, particularly over large distances when carried by aerosol droplets with long survival times. Efficient sampling of virus-loaded aerosol in combination with a low limit of detection of the collected virus could enable rapid and early detection of airborne influenza virus at the point-of-care setting. Here, we demonstrate a successful sampling and detection of airborne influenza virus using a system specifically developed for such applications. Our system consists of a custom-made electrostatic precipitation (ESP)-based bioaerosol sampler that is coupled with downstream quantitative polymerase chain reaction (qPCR) analysis. Aerosolized viruses are sampled directly into a miniaturized collector with liquid volume of 150 μL, which constitutes a simple and direct interface with subsequent biological assays. This approach reduces sample dilution by at least one order of magnitude when compared to other liquid-based aerosol bio-samplers. Performance of our ESP-based sampler was evaluated using influenza virus-loaded sub-micron aerosols generated from both cultured and clinical samples. Despite the miniaturized collection volume, we demonstrate a collection efficiency of at least 10% and sensitive detection of a minimum of 3721 RNA copies. Furthermore, we show that an improved extraction protocol can allow viral recovery of down to 303 RNA copies and a maximum sampler collection efficiency of 47%. A device with such a performance would reduce sampling times dramatically, from a few hours with current sampling methods down to a couple of minutes with our ESP-based bioaerosol sampler.

  • 103.
    Lamarche, Anick
    et al.
    KTH, School of Computer Science and Communication (CSC), Speech, Music and Hearing, TMH, Music Acoustics.
    Ternström, Sten
    KTH, School of Computer Science and Communication (CSC), Speech, Music and Hearing, TMH, Music Acoustics.
    Hertegård, Stellan
    Karolinska Institutet.
    Not just sound: Supplementing the voice range profile with the singer's ownperceptions of vocal challenges2009In: Logopedics, Phoniatrics, Vocology, ISSN 1401-5439, E-ISSN 1651-2022, Vol. 34, no 1, p. 3-10Article in journal (Refereed)
    Abstract [en]

    A commercial phonetograph was complemented with a response button, such that presses resulted in marked regions in the voice range profile (VRP). This study reports the VRP data of 16 healthy female professionally trained singers (7 mezzosopranos and 9 sopranos). Subjects pressed the button to indicate sensations of vocal instability or reduced control during phonation. Each press thereby marked potential areas of difficulty. A method is presented to quantify the consistency of button use for repeated tasks. The pattern of button presses was significantly consistent within subjects. As expected, the singers pressed at the extremes of VRP contours as well as at register transitions. These results and the potential of the method for the assessment of vocal problems of singers are discussed.

  • 104.
    Langer, Krzysztof
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Nano Biotechnology.
    Jönsson, Håkan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Nano Biotechnology.
    Rapid production and recovery of cell spheroids by automated droplet microfluidics2019In: bioRxivArticle in journal (Refereed)
    Abstract [en]

    Droplet microfluidics enables high throughput cell processing, analysis and screening by miniaturizing the reaction vessels to nano- or pico-liter water-in oil droplets, but like many other microfluidic formats, droplet microfluidics have not been interfaced with or automated by laboratory robotics. Here we demonstrate automation of droplet microfluidics based on an inexpensive liquid handling robot for the automated production of human scaffold-free cell spheroids, using pipette actuation and interfacing the pipetting tip with a droplet generating microfluidic chip. In this chip we produce highly mono-disperse 290μm droplets with diameter CV of 1.7%. By encapsulating cells in these droplets, we produce cell spheroids in droplets and recover them to standard formats at a throughput of 85000 spheroids per microfluidic circuit per hour. The viability of the cells in spheroids remains high after recovery only decreased by 4% starting from 96% after 16 hours incubation in nanoliter droplets. Scaffold-free cell spheroids and 3D tissue constructs recapitulate many aspects of functional human tissue more accurately than 2D or single cell cultures, but assembly methods for spheroids, e.g. hanging drop micro-plates, has had limited throughput. The increased throughput and decreased cost of our method enables spheroid production at the scale needed for lead discovery drug screening and approaches the cost where these micro tissues could be used as building blocks for organ scale regenerative medicine.

  • 105.
    Larsson, David
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Spuhler, Jeannette H.
    Petersson, Sven
    Nordenfur, Tim
    Hoffman, Johan
    KTH, School of Computer Science and Communication (CSC), High Performance Computing and Visualization (HPCViz).
    Colarieti-Tosti, Massimiliano
    Winter, Reidar
    Larsson, Matilda
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Multimodal validation of patient-specific intraventricular flow simulations from 4D echocardiography2016In: 2016 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IUS), IEEE conference proceedings, 2016Conference paper (Refereed)
    Abstract [en]

    The combination of refined medical imaging techniques and computational fluid dynamics (CFD) models has enabled the study of complex flow behavior on a highly regional level. Recently, we have developed a platform for patient-specific CFD modelling of blood flow in the left ventricle (LV), with input data and required boundary conditions acquired from 4D echocardiography. The platform robustness has been evaluated with respect to input variable variations, but for any clinical implementation model flow validation is essential. Therefore, the aim of this study is to evaluate the accuracy of the patient-specific CFD model against multimodal image-based flow measurements. For the validation, 4D echocardiography was acquired from two healthy subjects, from which LV velocity fields were simulated. In-vivo flows from the same two subjects were then acquired by pulsed wave (PW) Doppler imaging over both LV-valves, and by cine phase-contract magnetic resonance imaging (PC-MRI) at eight defined anatomical planes in the LV. By fusing PC-MRI and the ultrasound acquisitions using a three-chamber alignment algorithm, simulated and measured flows were quantitatively compared. General flow pattern correspondence was observed, with a mean error of 1.4 cm/s and root mean square deviation of 5.7 cm/s for all measured PC-MRI LV-planes. For the PW-Doppler comparison, a mean error of 3.6 cm/s was reported. Overall, the following work represents a validation of the proposed patient-specific CFD platform, and the agreement with clinical data highlight the potential for future clinical use of the models.

  • 106.
    Larsson, Matilda
    KTH, School of Technology and Health (STH), Medical Engineering.
    Quantification and Visualization of Cardiovascular Function using Ultrasound2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    There is a large need for accurate methods detecting cardiovascular diseases, since they are one of the leading causes of mortality in the world, accounting for 29.3% of all deaths. Due to the complexity of the cardiovascular system, it is very challenging to develop methods for quantification of its function in order to diagnose, prevent and treat cardiovascular diseases. Ultrasound is a technique allowing for inexpensive, noninvasive imaging, but requires an experienced echocardiographer. Nowadays, methods like Tissue Doppler imaging (TDI) and Speckle tracking imaging (STI), measuring motion and deformation in the myocardium and the vessel walls, are getting more common in routine clinical practice, but without a proper visualization of the data provided by these methods, they are time-consuming and difficult to interpret. Thus, the general aim of this thesis was to develop novel ultrasound-based methods for accurate quantification and easily interpretable visualization of cardiovascular function.

    Five methods based on TDI and STI were developed in the present studies. The first study comprised development of a method for generation of bull’s-eye plots providing a color-coded two-dimensional visualization of myocardial longitudinal velocities. The second study proposed the state diagram of the heart as a new circular visualization tool for cardiac mechanics, including segmental color-coding of cardiac time intervals. The third study included development of a method describing the rotation pattern of the left ventricle by calculating rotation axes at different levels of the left ventricle throughout the cardiac cycle. In the fourth study, deformation data from the artery wall were tested as input to wave intensity analysis providing information of the ventricular – arterial interaction. The fifth study included an in-silico feasibility study to test the assessment of both radial and longitudinal strain in a kinematic model of the carotid artery.

    The studies showed promising results indicating that the methods have potential for the detection of different cardiovascular diseases and are feasible for use in the clinical setting. However, further development of the methods and both quantitative comparison of user dependency, accuracy and ease of use with other established methods evaluating cardiovascular function, as well as additional testing of the clinical potential in larger study populations, are needed.

  • 107.
    Larsson, Matilda
    KTH, School of Technology and Health (STH), Medical Engineering.
    The rotation axis of the left ventricle - A new concept derived from ultrasound data in healthy individualsManuscript (preprint) (Other (popular science, discussion, etc.))
    Abstract [en]

    Different modalities have been used to describe the circumferential motion of the left ventricle (LV) and studies have indicated LV twist to be an additional integral component in LV function. So far, only amplitudes of rotation have been reported, whereas the rotation pattern of the LV has not been fully described. However, data from a previous study on regional rotation have indicated that the axis around which the LV rotates, is not congruent to the longitudinal axis of the LV. The aim of the present study was to develop an ultrasound-based method to calculate the rotation axis of the LV in a three-dimensional aspect throughout the cardiac cycle and to apply it in a group of healthy individuals. An algorithm for calculation of rotation axes at the basal, mid-, apical and transitional levels of the LV was developed. By constructing a simplified model of the LV, based on rotation amplitudes measured at the basal, mid- and apical levels, rotation planes with similar values of rotation could be calculated at each level. The transition plane was defined as where the rotation values shifted from positive to negative. An overview of the rotation pattern was achieved by displaying data on deflection (angle between the rotation axis and the longitudinal axis of the LV) and direction (defined as the angle in a short-axis view of the LV with zero degrees at the lateral wall and increasing angles counterclockwise) of the rotation axes throughout the cardiac cycle. The deflection differed significantly from zero in all tested time points, i.e. the rotation axis was not congruent to the longitudinal axis of the LV. Rayleigh’s test for uniformity demonstrated a significant mean direction for each of the axes for the majority of the tested time points. Thus, the axis of rotation at different levels of the LV displayed a physiological pattern, where also stability of rotation could be assessed. Furthermore, the angle and level of the transition plane could be described over time. This new way of assessing rotational function provides further insight into the complexity of LV mechanics. The method has acceptable reproducibility but the potential clinical use of this method needs to be validated in further studies.

  • 108.
    Larsson, Tore J
    KTH, School of Technology and Health (STH), Centres, Centre for Health and Building, CHB.
    Safety Management - Technology and health: Invited keynote lecture2004In: Health and Safety at Public Works, 2004Conference paper (Refereed)
  • 109.
    Laura Marie, Feeney
    et al.
    Uppsala University.
    Charalampos, Orfanidis
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Health Informatics and Logistics.
    Jacobsson, Martin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Health Informatics and Logistics.
    Per, Gunningberg
    Uppsala University.
    Poster Abstract: Preliminary results on LoRaWAN and IEEE 802.15.4-SUN Interference2018Conference paper (Refereed)
    Abstract [en]

    We present some preliminary results on LoRaWAN and IEEE 802.15.4- SUN interference in urban environments. The results are based on a simple simulation that is parameterized using PHY layer measurements of controlled interference scenarios

  • 110.
    Leirs, Karen
    et al.
    KU Leuven.
    Sandström, Niklas
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Ladhani, Laila
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Spasic, Dragana
    KU Leuven.
    Ostanin, Victor
    University of Cambridge.
    Klenerman, David
    University of Cambridge.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Microsystem Technology (Changed name 20121201).
    Ghosh, Sourav
    Loughborough University.
    Lammertyn, Jeroen
    KU Leuven.
    Screening of antibodies for the development of a fast and sensitivie influenza: A nucleoprotein detection on a nonlinear acoustic sensor2014Conference paper (Refereed)
  • 111.
    Leirs, Karen
    et al.
    MeBioS - Biosensor group, KU Leuven.
    Sandström, Niklas
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Ladhani, Laila
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Spasic, Dragana
    MeBioS - Biosensor group, KU Leuven.
    Ostanin, Victor
    University of Cambridge.
    Klenerman, David
    University of Cambridge.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Lammertyn, Jeroen
    KU Leuven.
    Ghosh, Sourav
    Loughborough University.
    Rapid ultra-sensitive detection of influenza A nucleoproteins using a microfluidic nonlinear acoustic sensor2014Conference paper (Refereed)
  • 112. Lin, Meng Meng
    et al.
    Kim, Hyung-Hwan
    Kim, Hyuck
    Dobson, Jon
    Kim, Do Kyung
    KTH, School of Information and Communication Technology (ICT), Material Physics, Functional Materials, FNM.
    Surface activation and targeting strategies of superparamagnetic iron oxide nanoparticles in cancer-oriented diagnosis and therapy2010In: NANOMEDICINE, ISSN 1743-5889, Vol. 5, no 1, p. 109-133Article, review/survey (Refereed)
    Abstract [en]

    The advanced fabrication and surface engineering of superparamagnetic iron oxide nanoparticles (SPIONs) could offer excellent physiochemical features for noninvasive tumor imaging and drug delivery. The key issues of realization of maximized selective cancer targeting of SPIONs are minimization of uptake by macrophages, preferential binding to cancerous cells over neighboring normal cells, visualization of tumor cells prior to and after treatment and triggered drug release into target cells in a controlled fashion. In this article, we summarize the current status of fabrication of multifunctional SPION-based nanodevices specially designed for cancer-oriented diagnosis and therapy, with a focus on potential malignancy-targeting ligands' identification and development as nanocarriers. A number of examples of passive and active targeting strategies - lymphoangiogenesis markers, cellular metabolite receptors, extracellular matrix component receptors, neuropeptide receptors and receptor-mediated bypass of the blood-brain barrier - are described in detail.

  • 113.
    Lindberg, Frida
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Öhberg, Fredrik
    Granåsen, Gabriel
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Grönlund, Christer
    Pennation angle dependency in skeletal muscle tissue doppler strain in dynamic contractions2011In: Ultrasound in Medicine and Biology, ISSN 0301-5629, E-ISSN 1879-291X, Vol. 37, no 7, p. 1151-1160Article in journal (Refereed)
    Abstract [en]

    Tissue velocity imaging (TVI) is a Doppler based ultrasound technique that can be used to study regional deformation in skeletal muscle tissue. The aim of this study was to develop a biomechanical model to describe the TVI strain's dependency on the pennation angle. We demonstrate its impact as the subsequent strain measurement error using dynamic elbow contractions from the medial and the lateral part of biceps brachii at two different loadings; 5% and 25% of maximum voluntary contraction (MVC). The estimated pennation angles were on average about 4 degrees in extended position and increased to a maximal of 13 degrees in flexed elbow position. The corresponding relative angular error spread from around 7% up to around 40%. To accurately apply TVI on skeletal muscles, the error due to angle changes should be compensated for. As a suggestion, this could be done according to the presented model.

  • 114.
    Lindh, Thomas
    et al.
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Orhan, Ibrahim
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Performance Control in Wireless Sensor Networks2009In: Pervasive Computing Technologies for Healthcare, 2009. PervasiveHealth 2009. 3rd International Conference on, IEEE , 2009Conference paper (Refereed)
    Abstract [en]

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

  • 115.
    Lindh, Thomas
    et al.
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Orhan, Ibrahim
    KTH, School of Technology and Health (STH), Medical Engineering.
    Performance Measurements and Control in Contention-Based Wireless Sensor Networks2009In: 6th Swedish National Computer Networking Workshop (SNCNW 2009), 2009Conference paper (Refereed)
    Abstract [en]

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

  • 116.
    Lindh, Thomas
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering.
    Orhan, Ibrahim
    KTH, School of Technology and Health (STH), Medical Engineering, Computer and Electronic Engineering.
    Performance Monitoring and Control in Contention-Based Wireless Sensor Networks2009In: Proceedings of the 2009 6th International Symposium on Wireless Communication Systems, ISWCS'09, NEW YORK: IEEE conference proceedings, 2009, p. 507-511Conference paper (Refereed)
    Abstract [en]

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

  • 117.
    Lindh, Thomas
    et al.
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Orhan, Ibrahim
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Gonga, Antonio
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    A performance monitoring method for wireless sensor networks2008In: PETRA '08 Proceedings of the 1st international conference on PErvasive Technologies Related to Assistive Environments, New York: ACM , 2008Conference paper (Refereed)
    Abstract [en]

    This paper presents a monitoring method and its implementation as a light-weight end-to-end performance meter for quality-demanding applications in wireless sensor networks. The use of performance feedback information for control and management is also considered. The method is evaluated in a wireless sensor network testbed for healthcare applications.

  • 118.
    Lundkvist, Andrea
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Norman, Gabriella
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    A 3D Visualization of White Blood Cell Populations: A Program to Visualize Analyzed Data from a Blood Sample2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The goal of this project was to write a program to plot populations of white blood cell types in three dimensions and reduce the information from four dimensions to three in order to make it possible to plot. The dimension reduction should be done with as little loss of information as possible. PCA, principal component analysis, was used to perform the dimension reduction. A program for this was written in MATLAB.

    The program that builds the plot of the populations was written in c# using Visual Studios. The visualization was made in Unity. It was possible to rotate and zoom into the plot to get a better view.

    The project was given by Boule Medical AB as a part of the development of a new product. Boule Medical AB only had 2D plots and requested a 3D plot in their new product. The program was handed over to Boule Medical AB for future development.

  • 119.
    Löfhed, Johan
    et al.
    University of Borås.
    Seoane, Fernando
    Thordstein, Magnus
    Salhgrenska University Hospital.
    Soft textile electrodes for EEG monitoring2010Conference paper (Refereed)
    Abstract [en]

    There is a need for long term monitoring of the brain during intensive care. This is e.g. the case for newborn babies that have been exposed to hypoxia during delivery. Electroencephalography (EEG) is the technique of choice. To get a clear and detailed view of the brain activity a large number of EEG electrodes should be used. Applying traditional electrodes one by one is a time-consuming and technically demanding work and therefore electrode caps are sometimes used. The existing caps have however been found to be suboptimal for long term monitoring because they may induce too high a pressure on the scalp of the babies. We have tested three different types of textile electrodes with regard to their potential use for EEG monitoring. The results show that soft conducting textile materials can indeed be used for EEG monitoring.

  • 120.
    Macias, Raul
    et al.
    Technical University of Catalonia.
    Seoane, Fernando
    University of Borås.
    Bragós, Ramon
    Technical University of Catalonia.
    Performance of the load-in-the-loop single Op-Amp voltage Controlled current source from the Op-Amp Parameters2010In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 224, no 1, p. 012008-Article in journal (Refereed)
    Abstract [en]

    In recent years, Electrical Bioimpedance (EBI) methods have gained importance. These methods are often based on obtaining impedance spectrum in the range of β-dispersion, i.e. from a few kHz up to some MHz. To measure EBI a constant current is often injected and the voltage across the tissue under study is recorded. Due to the performance of the current source influences the performance of the entire system, in terms of frequency range, several designs have been implemented and studied. In this paper the basic structure of a Voltage-Controlled Current Source based on a single Op-Amp in inverter configuration with a floating load, known as load-in-the-loop current source, is revisited and studied deeply. We focus on the dependence of the output impedance with the circuit parameters, i.e. the feedback resistor and the inverter-input resistor, and the Op-Amp main parameters, i.e. open loop gain, CMRR and input impedance. After obtaining the experimental results, using modern Op-Amps, and comparing to the theoretical and simulated ones, they confirm the design under study can be a good solution for multi-frequency wideband EBI applications because of higher values of the output impedance than 100kΩ at 1MHz are obtained. Furthermore, an enhancement of the basic design, using a current conveyor as a first stage, is proposed, studied and implemented.

  • 121.
    Manouras, Aristomenis
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering.
    Shala, Arben
    Nyktari, Evangelia
    Shahgaldi, Kambiz
    Winter, Reidar
    Vardas, Panagiotis
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Nowak, Jacek
    Are measurements of systolic myocardial velocities and displacement with colour and spectral Tissue Doppler compatible?2009In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 7, p. 29-Article in journal (Refereed)
    Abstract [en]

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

  • 122.
    Marlevi, David
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Medical Imaging. Karolinska Institutet, Stockholm, Sweden.
    Ruijsink, B.
    Balmus, M.
    Dillon-Murphy, D.
    Fovargue, D.
    Pushparajah, K.
    Bertoglio, C.
    Colarieti-Tosti, Massimiliano
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Medical Imaging. Karolinska Institutet, Stockholm, Sweden.
    Larsson, Matilda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Medical Imaging.
    Lamata, P.
    Figueroa, C. A.
    Razavi, R.
    Nordsletten, D. A.
    Estimation of Cardiovascular Relative Pressure Using Virtual Work-Energy2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, no 1, article id 1375Article in journal (Refereed)
    Abstract [en]

    Many cardiovascular diseases lead to local increases in relative pressure, reflecting the higher costs of driving blood flow. The utility of this biomarker for stratifying the severity of disease has thus driven the development of methods to measure these relative pressures. While intravascular catheterisation remains the most direct measure, its invasiveness limits clinical application in many instances. Non-invasive Doppler ultrasound estimates have partially addressed this gap; however only provide relative pressure estimates for a range of constricted cardiovascular conditions. Here we introduce a non-invasive method that enables arbitrary interrogation of relative pressures throughout an imaged vascular structure, leveraging modern phase contrast magnetic resonance imaging, the virtual work-energy equations, and a virtual field to provide robust and accurate estimates. The versatility and accuracy of the method is verified in a set of complex patient-specific cardiovascular models, where relative pressures into previously inaccessible flow regions are assessed. The method is further validated within a cohort of congenital heart disease patients, providing a novel tool for probing relative pressures in-vivo.

  • 123.
    Marquez, Juan Carlos
    et al.
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Ferreira, Javier
    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).
    Buendia, Ruben
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Textile electrode straps for wrist-to-ankle bioimpedance measurements for Body Composition Analysis: Initial validation & experimental results2010In: 2010 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC), IEEE Engineering in Medicine and Biology Society , 2010, p. 6385-6388Conference paper (Refereed)
    Abstract [en]

    Electrical Bioimpedance (EBI) is one of the non-invasive monitoring technologies that could benefit from the emerging textile based measurement systems. If reliable and reproducible EBI measurements could be done with textile electrodes, that would facilitate the utilization of EBI-based personalized healthcare monitoring applications. In this work the performance of a custom-made dry-textile electrode prototype is tested. Four-electrodes ankle-to-wrist EBI measurements have been taken on healthy subjects with the Impedimed spectrometer SFB7 in the frequency range 5 kHz to 1 MHz. The EBI spectroscopy measurements taken with dry electrodes were analyzed via the Cole and Body Composition Analysis (BCA) parameters, which were compared with EBI measurements obtained with standard electrolytic electrodes. The analysis of the obtained results indicate that even when dry textile electrodes may be used for EBI spectroscopy measurements, the measurements present remarkable differences that influence in the Cole parameter estimation process and in the final production of the BCA parameters. These initial results indicate that more research work must be done to in order to obtain a textile-based electrode that ensures reliable and reproducible EBI spectroscopy measurements.

  • 124.
    Marquez, Juan Carlos
    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).
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Skin-electrode contact area in electrical bioimpedance spectroscopy. Influence in total body composition assessment2011In: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, IEEE Engineering In Medicine and Biology Society , 2011, Vol. 2011, p. 1867-1870Conference paper (Refereed)
    Abstract [en]

    Electrical Bioimpedance Spectroscopy (EBIS) has been widely used for assessment of total body composition and fluid distribution. (EBIS) measurements are commonly performed with electrolytic electrodes placed on the wrist and the ankle with a rather small skin-electrode contact area. The use of textile garments for EBI requires the integration of textrodes with a larger contact area surrounding the limbs in order to compensate the absence of electrolytic medium commonly present in traditional Ag/AgCl gel electrodes. Recently it has been shown that mismatch between the measurements electrodes might cause alterations on the EBIS measurements. When performing EBIS measurements with textrodes certain differences have been observed, especially at high frequencies, respect the same EBIS measurements using Ag/AgCl electrodes. In this work the influence of increasing the skin-electrode area on the estimation of body composition parameters has been studied performing experimental EBIS measurement. The results indicate that an increment on the area of the skin-electrode interface produced noticeable changes in the bioimpedance spectra as well as in the body composition parameters. Moreover, the area increment showed also an apparent reduction of electrode impedance mismatch effects. This influence must be taken into consideration when designing and testing textile-enable EBIS measurement systems.

  • 125. Marquez, Juan Carlos
    et al.
    Seoane, Fernando
    Välimäki, Elina
    University of Borås.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
    Comparison of dry-textile electrodes for electrical bioimpedance spectroscopy measurements2010Conference paper (Refereed)
    Abstract [en]

    Textile Electrodes have been widely studied for biopotentials recordings, specially for monitoring the cardiac activity. Commercially available applications, such as Adistar T-shirt and Textronics Cardioshirt, have proved a good performance for heart rate monitoring and are available worldwide. Textile technology can also be used for Electrical Bioimpedance Spectroscopy measurements enabling home and personalized health monitoring applications however solid ground research about the measurement performance of the electrodes must be done prior to the development of any textile-enabled EBI application. In this work a comparison of the measurement performance of two different types of dry-textile electrodes and manufacturers has been performed against standardized RedDot 3M Ag/AgCl electrolytic electrodes. 4-Electrode, whole body, Ankle-to-Wrist EBI measurements have been taken with the Impedimed spectrometer SFB7 from healthy subjects in the frequency range of 3kHz to 500kHz. Measurements have been taken with dry electrodes at different times to study the influence of the interaction skin-electrode interface on the EBI measurements. The analysis of the obtained complex EBI spectra shows that the measurements performed with textile electrodes produce constant and reliable EBI spectra. Certain deviation can be observed at higher frequencies and the measurements obtained with Textronics and Ag/AgCl electrodes present a better resemblance. Textile technology, if successfully integrated it, may enable the performance of EBI measurements in new scenarios allowing the rising of novel wearable monitoring applications for home and personal care as well as car safety.

  • 126. Mohino-Herranz, Inma
    et al.
    Gil-Pita, Roberto
    Ferreira, Javier
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. University of Boras, Boras, Sweden.
    Rosa-Zurera, Manuel
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. University of Boras, Boras, Sweden.
    Assessment of Mental, Emotional and Physical Stress through Analysis of Physiological Signals Using Smartphones2015In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 15, no 10, p. 25607-25627Article in journal (Refereed)
    Abstract [en]

    Determining the stress level of a subject in real time could be of special interest in certain professional activities to allow the monitoring of soldiers, pilots, emergency personnel and other professionals responsible for human lives. Assessment of current mental fitness for executing a task at hand might avoid unnecessary risks. To obtain this knowledge, two physiological measurements were recorded in this work using customized non-invasive wearable instrumentation that measures electrocardiogram (ECG) and thoracic electrical bioimpedance (TEB) signals. The relevant information from each measurement is extracted via evaluation of a reduced set of selected features. These features are primarily obtained from filtered and processed versions of the raw time measurements with calculations of certain statistical and descriptive parameters. Selection of the reduced set of features was performed using genetic algorithms, thus constraining the computational cost of the real-time implementation. Different classification approaches have been studied, but neural networks were chosen for this investigation because they represent a good tradeoff between the intelligence of the solution and computational complexity. Three different application scenarios were considered. In the first scenario, the proposed system is capable of distinguishing among different types of activity with a 21.2% probability error, for activities coded as neutral, emotional, mental and physical. In the second scenario, the proposed solution distinguishes among the three different emotional states of neutral, sadness and disgust, with a probability error of 4.8%. In the third scenario, the system is able to distinguish between low mental load and mental overload with a probability error of 32.3%. The computational cost was calculated, and the solution was implemented in commercially available Android-based smartphones. The results indicate that execution of such a monitoring solution is negligible compared to the nominal computational load of current smartphones.

  • 127. Molina, Daniel Martinez
    et al.
    Lundbäck, Anna-Karin
    KTH, School of Technology and Health (STH).
    Niegowski, Damian
    Eshaghi, Said
    Expression and purification of the recombinant membrane protein YidC: A case study for increased stability and solubility2008In: Protein Expression and Purification, ISSN 1046-5928, E-ISSN 1096-0279, Vol. 62, no 1, p. 49-52Article in journal (Refereed)
    Abstract [en]

    YidC is an inner membrane protein from Escherichia coli and is an essential component in insertion, translocation and assembly of membrane proteins in the membranes. Previous purification attempts resulted in heavy aggregates and precipitated protein at later stages of purification. Here we present a rapid and straightforward stability screening strategy based on gel filtration chromatography, which requires as little as 10 mu g of protein and takes less than 15 min to perform. With this technique, we could rapidly screen several buffers in order to identify an optimum condition that stabilizes purified YidC. After optimization we could obtain several milligrams of purified YidC that could be easily prepared at high concentrations and that was stable for weeks at +4 degrees C. The isolated protein is thus well suited for structural studies.

  • 128. Mortier, P.
    et al.
    Holzapfel, Gerhard A.
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.), Biomechanics.
    De Beule, M.
    Van Loo, D.
    Taeymans, Y.
    Segers, P.
    Verdonck, P.
    Verhegghe, B.
    A Novel Simulation Strategy for Stent Insertion and Deployment in Curved Coronary Bifurcations: Comparison of Three Drug-Eluting Stents2010In: Annals of Biomedical Engineering, ISSN 0090-6964, E-ISSN 1573-9686, Vol. 38, no 1, p. 88-99Article in journal (Refereed)
    Abstract [en]

    The introduction of drug-eluting stents (DES) has reduced the occurrence of restenosis in coronary arteries. However, restenosis remains a problem in stented coronary bifurcations. This study investigates and compares three different second generation DESs when being implanted in the curved main branch of a coronary bifurcation with the aim of providing better insights into the related changes of the mechanical environment. The 3D bifurcation model is based on patient-specific angiographic data that accurately reproduce the in vivo curvatures of the vessel segments. The layered structure of the arterial wall and its anisotropic mechanical behavior are taken into account by applying a novel algorithm to define the fiber orientations. An innovative simulation strategy considering the insertion of a folded balloon catheter over a guide wire is proposed in order to position the stents within the curved vessel. Straightening occurs after implantation of all stents investigated. The resulting distributions of the wall stresses are strongly dependent on the stent design. Using a parametric modeling approach, two design modifications, which reduce the predicted maximum values of the wall stress, are proposed and analyzed.

  • 129.
    Moy, Linda
    et al.
    New York University School of Medicine.
    Noz, Marilyn E.
    New York University School of Medicine.
    Maguire, Gerald Q., Jr.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Communication Systems, CoS (closed 2012-01-01).
    Melsaether, Amy
    New York University School of Medicine.
    Deans, Abby E.
    New York University School of Medicine.
    Murphy-Walcott, Antoinette D.
    New York University School of Medicine.
    Ponzo, Fabio
    New York University School of Medicine.
    Role of Fusion of Prone FDG-PET and Magnetic Resonance Imaging of the Breasts in the Evaluation of Breast Cancer2010In: The Breast Journal, ISSN 1075-122X, E-ISSN 1524-4741, Vol. 16, no 4, p. 369-376Article in journal (Refereed)
    Abstract [en]

    The purpose of this study is to report further about the statistically significant results from a prospective study, which suggests that fusion of prone F-18 Fluoro-deoxy-glucose (FDG) positron emission tomography (PET) and magnetic resonance (MR) breast scans increases the positive predictive value (PPV) and specificity for patients in whom the MR outcome alone would be nonspecific. Thirty-six women (mean age, 43 years; range, 24-65 years) with 90 lesions detected on MR consented to undergo a FDG-PET scan. Two blinded readers evaluated the MR and the computer tomography (CT) attenuation-corrected prone FDG-PET scans side-by-side, then after the volumes were superimposed (fused). A semiautomatic, landmark-based program was used to perform nonrigid fusion. Pathology and radiologic follow-up were used as the reference standard. The sensitivity, specificity, PPV, negative predictive value (NPV), and accuracy (with 95% confidence intervals) for MR alone, FDG-PET alone, and fused MR and FDG-PET were calculated. The median lesion size measured from the MR was 2.5 cm (range, 0.5-10 cm). Histologically, 56 lesions were malignant, and 15 were benign. Nineteen lesions were benign after 20-47 months of clinical and radiologic surveillance. The sensitivity of MR alone was 95%, FDG-PET alone was 57%, and fusion was 83%. The increase in PPV from 77% in MR alone to 98% when fused and the increase in specificity from 53% to 97% were statistically significant (p < 0.05). The false-negative rate on FDG-PET alone was 26.7%, and after fusion this number was reduced to 9%. FDG-PET and MR fusions were helpful in selecting which lesion to biopsy, especially in women with multiple suspicious MR breast lesions.

  • 130. Murphy, M J
    et al.
    Isaakson, M
    Jaldén, Joakim
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Adaptive filtering to predict lung tumor motion during free breathing2002In: CARS 2002: COMPUTER ASSISTED RADIOLOGY AND SURGERY, PROCEEDINGS, BERLIN: SPRINGER-VERLAG BERLIN , 2002, p. 539-544Conference paper (Refereed)
    Abstract [en]

    Breathing-induced tumor motion during radiation therapy can be compensated either by crating or correcting the pointing of the radiation beam, but these techniques involve time delays in the corrective response. We have analyzed the accuracy of adaptive filter algorithms in predicting tumor positions with sufficient lead time to compensate for these systematic delays. Tumor and chest motion during respiration has been recorded fluoroscopically for lung cancer patients, using gold fiducials implanted in the tumors to enhance visibility. The motions been analyzed for predictability up to 1.0 second in advance Using tapped delay line, Kalman filter, and neural network filter algorithms. Breathing patterns are not stationary in time. Both internal tumor and external chest movement can show amplitude and period modulations during a 30 second interval. Tapped delay line and other stationary filters cannot compensate for the changes and consequently have poor predictability. The predictive accuracy of adaptive filters has little dependence oil the type of algorithm, but depends mainly on the frequency of updating and deteriorates rapidly when predicting more than 0.2 seconds in advance of the breathing signal. Longer-period (e.g., 30 seconds) variability in breathing requires frequent adaptation of the filter parameters.

  • 131.
    Mårtensson, Mattias
    KTH, School of Technology and Health (STH), Medical Engineering.
    Evaluation of Errors and Limitations in Ultrasound Imaging Systems2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    There are binding regulations requiring safety and efficacy aspects of medical devices. The requirements ask for documentation that the devices are safe and effective for their intended use, i.e. if a device has a measuring function it must be correct. In addition to this there are demands for quality systems describing development, manufacturing, labelling, and manufacturing of a device. The requirements are established to guarantee that non-defective medical devices are used in the routine clinical practice. The fast rates in which the imaging modalities have evolved during the last decades have resulted in numerous new diagnostic tools, such as velocity and deformation imaging in ultrasound imaging. However, it seems as if the development of evaluation methods and test routines has not been able to keep up the same pace. Two of the studies in this thesis, Study I and IV, showed that computed tomography-based and ultrasound based volume measurements can yield very disparate measurements, and that tissue Doppler imaging-based ultrasound measurements can be unreliable.

    Furthermore, the new ultrasound modalities impose higher demands on the ultrasound transducers. Transducers are known to be fragile, but defective transducers were less of a problem earlier when the ultrasound systems to a lesser extent were used for measurements. The two other studies, Study II and III, showed that serious transducer errors are very common, and that annual testing of the transducers is not sufficient to guarantee an error free function.

    The studies in the thesis indicate that the system with Notified Bodies, in accordance with the EU’s Medical Device Directive, checking the function and manufacturing of medical devices does not work entirely satisfactory. They also show that the evaluation of new methods have led to the undesirable situation, where new measuring tools, such as volume rendering from imaging systems, and tissue Doppler-based velocity and deformation imaging in echocardiography are available for clinicians without proven knowledge about their accuracy.

  • 132.
    Mårtensson, Mattias
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Bjällmark, Anna
    KTH, School of Technology and Health (STH), Medical Engineering.
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Evaluation of tissue Doppler-based velocity and deformation imaging: a phantom study of ultrasound systems.2011In: European Journal of Echocardiography, ISSN 1525-2167, E-ISSN 1532-2114, Vol. 12, no 6, p. 467-476Article in journal (Refereed)
    Abstract [en]

    AIMS: The objective of this study was to test the accuracy and diagnostic interchangeability of tissue Doppler-based displacement, velocity, strain, and strain rate measurements in commercially used ultrasound (US) systems. METHODS AND RESULTS: Using an in-house made phantom, four different US scanner models were evaluated. Two different scanners of the same model were tested, and one scanner acquisition was tested twice with two generations of the same workstation giving six test results in total. The scanners were in active clinical use and are subject to regular maintenance checks. There were three displacement and four velocity results that stood out from the rest and could be regarded as accurate and interchangeable. Among the deformation measurements, three acceptable strain results were found while there were no acceptable strain rate results. Furthermore, the study showed that measurements from scanners of the same model, same acquisition post-processed on different workstations and repeated measurements from the same scanner, can yield disparate results. CONCLUSION: Measurements that are accurate and of interchangeable use can be found for displacement and velocity measurements, but are less likely to be found for strain and strain rate measurements. It is strongly recommended that the ability of each individual US scanner to measure displacement, velocity, strain, and strain rate is evaluated before it is introduced into clinical practice, and it must always be evaluated together with the workstation the scanner is intended to be used in conjunction with.

  • 133.
    Mårtensson, Mattias
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
    Winter, Reidar
    Cederlund, Kerstin
    Ripsweden, Jonaz
    Mir-Akbari, Habib
    Nowak, Jacek
    Brodin, Lars-Åke
    KTH, School of Technology and Health (STH), Medical Engineering.
    Assessment of left ventricular volumes using simplified 3-D echocardiography and computed tomography - a phantom and clinical study2008In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 6Article in journal (Refereed)
    Abstract [en]

    Objectives: To compare the accuracy of simplified 3-dimensional (3-D) echocardiography vs. multi-slice computed tomography (MSCT) software for the quantification of left ventricular (LV) volumes. Design: Three-D echocardiography (3-planes approach) and MSCT-CardIQ software were calibrated by measuring known volumes of 10 phantoms designed to closely mimic blood-endocardium interface. Subsequently, LV volumes were measured with both the methods in 9 patients referred routinely for coronary angiography and the agreement between the measurements was evaluated. Results: Simplified 3D-echocardiography provided higher degree of agreement between the measured and true phantom volumes (mean difference 0 +/- 1 ml, variation range + 4 to -4 ml) than MSCT software (mean difference 6 +/- 5 ml; variation range + 22 to -10 ml). The agreement between LV measurements in the patients was considerably poorer, with significantly larger volumes produced by MSCT (mean difference - 23 +/- 40 ml, variation between + 93 and -138 ml). Conclusion: Simplified 3-D echocardiography provides more accurate assessment of phantom volumes than MSCT-CardIQ software. The discrepancy between the results of LV measurements with the two methods is even greater and does not warrant their interchangeable diagnostic use.

  • 134.
    Najar, salwan
    KTH, School of Technology and Health (STH).
    Simulering av 1-Wire sensorer2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The 1-wire bus is a communication bus system which is designed to provide data, signals and power over a single signal with low data rates, a high resolution and a long range. It is typically used to communicate with small inexpensive devices, as temperature sensors, which is worked as a slave with the master computer (PC).

    The 1-wire bus system provides the sufficient control and operation signal, a unique ID serial number of each sensor and it supports multiple temperature sensors by a driving power (Parasite Power) on single line.

    On the 1-Wire bus system, temperature sensors are supplied by two types of power supplies, external Power supply and Parasitic Power.

    The aim of this project is to program the microprocessor (Arduino) by using Arduino programming language to work as a temperature sensor type DS18B20 and also as a slave on the 1-Wire bus system.

    This report explains the 1-Wire bus system techniques and how the communication is achieved between the master and the slave (sensors) to measure the temperature values.

    The measured temperature values are collected from the output of each active sensor on the 1-Wire bus. These data are displayed by the personal computer (PC) which is worked as a master on the 1-Wire bus, and the data are represent the measured temperature values from twelve active sensors on the bus system.

    In this thesis, the temperature values from the 12 active sensors can be read and displayed on the master (PC) by using the following programs: Open Logger One Wire (OLOW) program, One Wire Viewer, DigiTemp and OWFS and I validated all the temperature values from these active sensors which are read and monitored by the drive bus programs. The comparison is done among the measured temperature values to see if the active sensors are given accurate temperature values with different drive bus programs.

    The project shows that the sensors can be connected in a network with the master, by using 1-Wire bus techniques. This thesis will be used by Karolinska University Hospital, and it can also be developed for different requirements in the future.

  • 135.
    Nolting, Andreas
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Sustainability and Industrial Dynamics.
    Companion Diagnostics Development and Commercialization: A Case Study from the Diagnostics’ Perspective2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The value proposition of Personalized Medicine is to deliver the “right drug, to the right patient, at the right time”. Companion diagnostics is the required tool for Personalized Medicine used to aid clinical decision making with the aim to identify patients who are most suitable for a given treatment approach and to avoid adverse effects. However, even 16 years after the first co-approval of a therapeutic drug and an associated diagnostic test (trastuzumab (Herceptin1) from Genentech and the HercepTest1 from Dako), the co-development and co-approval of drug-diagnostic pairs is a challenging task.This study has the aim to identify major challenges for diagnostics companies when developing and commercializing companion diagnostics. This is achieved by (1) a literature research and (2) an empirical case study in form of interviews with diagnostics companies. The collected data is analyzed and discussed with focus on current regulatory and reimbursement frameworks in the USA and European Union. The co-development strategies and business models of companion diagnostics developers are identified.The conclusion of this study is that the major hurdles for companion diagnostics development and commercialization are gaps in scientific evidence and lacking regulatory guidelines for co-development and clinical biomarker studies. Companion diagnostics commercialization is further challenged by poor reimbursement levels. The main strategy of diagnostics companies to address these challenges is the demonstration of a beneficial outcome for patients in form of clinical studies. Small companies with limited resources for clinical research receive funding from academic research grants, patient support groups, pharmaceutical industry, and governmental Innovation agencies.Finally the formation of a new “pharma-diagnostics” sectoral innovation system as a result of the emerging paradigm of stratified medicine has been proposed.

  • 136.
    Nordberg, Axel
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Treatment of Bone Fractures Using Fibre Reinforced Adhesive Patches2009Doctoral thesis, comprehensive summary (Other academic)
  • 137.
    Nordberg, Axel
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Antoni, Per
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Malkoch, Michael
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Fibre reinforced Thiol-Ene patch fixation of bone fracturesManuscript (preprint) (Other academic)
  • 138.
    Nordberg, Axel
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Halldin, Peter
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Evaluation of fiber reinforced adhesive fixation of vertebral fractures; an experimental and numerical studyManuscript (preprint) (Other academic)
  • 139.
    Nordberg, Axel
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Montañez, Maria I.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    Ramakrishnan, Subashiyni
    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, Coating Technology.
    Hult, Anders
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Coating Technology.
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Higly adhesive DOPA primers for fibre reinforced Thiol-Ene patch fixation of bone fractures.Manuscript (preprint) (Other academic)
  • 140.
    Nordberg, Axel
    et al.
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    von Holst, Hans
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Brolin, Karin
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Beckman, Anders
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures.
    Vertebral fractures fixation with composite patch fibre reinforced adhesives2007In: Bio-medical materials and engineering, ISSN 0959-2989, E-ISSN 1878-3619, Vol. 17, no 5, p. 299-308Article in journal (Refereed)
    Abstract [en]

    Purpose: The aim is to investigate fixation of cervical vertebral fractures by patching it with a composite laminate of adhesive and fibres, in comparison with use of only adhesives. Material and methods: The composite fixation was tested on bonded roe deer vertebrae. 25 specimens were sawed in two halves, creating a generic fracture, and thereafter bonded. The adhesives used were a dental system, Scotchbond XT, and a cyanoacrylate, M-bond 200. The fibres used were unidirectional carbon fibres and randomly distributed E-glass fibres. The composites were applied as a 7 mm wide patch circumferential along the induced fracture. Reference specimens for comparison were also made. The ultimate tensile strength was tested in an Instron 5567. The failure site was examined with a microscope. Strain vectors were tracked using Digital Speckle Analysis. Results: Scotchbond XT + E-glass fibres gave best results, with a tensile strength of 3.5 N/mm circumferential length (24.3% of reference). All composites had lower stiffness than cortical bone. The dental adhesive fibre composites gave better results than the cyanoacrylate fibre composites. In all cases fibre reinforced adhesive composite gave better results than adhesive without fibre reinforcement. Conclusion: Fibre-adhesive composite is a promising technique for fixating cervical vertebral fractures.

  • 141.
    Nordling, Torbjörn E. M.
    et al.
    Department of Electrical Engineering and Automation, University of Vaasa.
    Koljonen, Janne
    Department of Electrical Engineering and Automation, University of Vaasa.
    Nyström, Josefina
    Bodén, Ida
    Lindholm-Sethson, Britta
    Geladi, Paul
    Alander, Jarmo T.
    Wavelength selection by genetic algorithms in near infrared spectra for melanoma diagnosis2005In: IFMBE Proceedings, Volume 11, 3rd European Medical & Biological Engineering Conference (EMBEC’05) in Prague (Czech Republic), 2005Conference paper (Refereed)
    Abstract [en]

    Early, reliable and fast diagnosis of melanoma is particularly important as the number of cases is increasing. In this paper, the potential of using near infrared spectroscopy for melanoma diagnosis is studied. The classification task is complicated by a low signal-to-noise ratio and the high dimensionality of the spectral data. Thus pre-selection of wavelength variables is required. Atypical naevi samples of patients were clinically classified, using the ABCD rule, and their near infrared spectra recorded. A nonlinear clustering model for spectral based classification was calibrated to the spectra and pathologist?s classification using a genetic algorithm. The genetic algorithm optimized the spectral based classification by selecting wavelengths correlated to melanoma. Some wavelength selections allowed correct classification of all samples in our dataset. The small size of the dataset and uncertainty in the clinical classification, however, limit the conclusions that can be drawn. Evidence for the existence of spectral regions that contain information needed for melanoma diagnosis is presented.

  • 142.
    Näsman, Per
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301), Safety Research (closed 20110301).
    Risk, Risk Analysis and Decision-making with Reference to Biostatistics and the Field of Medicine2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Risk, risk analysis and decision-making are essential aspects of health care andmedicine, for patients as well as for physicians and for society as a whole, andthe concept of risk and risk analysis in decision-making has a long history. Theword risk has many different interpretations and has no commonly accepteddefinition. In this thesis, we shall let risk stand for the combination of randomor uncertain events with negative consequences for human health, life and/orwelfare and/or the environment together with some measures of the likelihoodof such events. We believe this is the dominant concept and understanding ofrisk, the risk being the likelihood or probability of an event followed by somenegative consequences or activities of that event.

    In this doctoral thesis, we focus on biostatistics, risks and risk analysis in thefield of medicine, a science which has been using methods from the area of riskanalysis for a long time. The seven papers (paper I - paper VII) presented inthis thesis, together with a general introduction to risk, risk analysis anddecision-making, will be used to illustrate and discuss risk analysis as a tool fordecision-making in the field of medicine. From my point a view, risk analysisin the field of medicine aims to reduce pain, raise the quality of life, reduce therisk of adverse events, compare cost efficiency between different treatmentregimes and prolong a healthy life. Based on results presented in the thesis, weconclude that biostatistics, risks and risk analysis used in the field of medicineare valuable methods for evaluation of hypotheses within the health care areaand a good basis for decision-making.

  • 143. Odeberg, J
    et al.
    Ahmadian, A
    Williams, Cecilia
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Uhlén, M
    Pontén, F
    Lundeberg, J
    Context-dependent Taq-polymerase-mediated nucleotide alterations, as revealed by direct sequencing of the ZNF189 gene: implications for mutation detection.1999In: Gene, ISSN 0378-1119, E-ISSN 1879-0038, Vol. 235, no 1-2Article in journal (Refereed)
    Abstract [en]

    We have recently reported on the genetic organisation of a novel Krüppel-like zinc finger, ZNF189, located to 9q22-q31. In that study we found no mutations in the coding sequence when using ZNF189 as a candidate gene for sporadic basal cell cancer and squamous cell cancer. Here, by direct sequencing of the proximal promotor of ZNF189, mutations were found to appear in a small hot-spot region in over 50% of analysed tumour samples, the majority being G to A substitutions. The hot-spot region spans a 24bp G-rich region. Repeated analyses of the original sample lysates fail to confirm each of these mutations; and frequently new mutations appear at neighbouring positions. Subsequent analysis with serial dilutions of genomic DNA and a cosmid harbouring the wild-type ZNF189 gene demonstrate that these sequence-specific alterations arise in the outer PCR-amplification when 50 copies or less of template are used. Although the mechanism of how these context-specific alterations arise is not proven, the results demonstrate a previously unreported type of PCR-mediated sequence-specific alteration that easily could have been interpreted as being of clinical relevance. The phenomena observed show that mutations detected by direct sequencing can be caused by PCR-introduced alterations. Consequently, this should be of general caution in mutation analysis of disease gene candidates when using small amounts of template, such as microdissected biopsies.

  • 144.
    Ohlander, Anna
    KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology.
    Foil-based Lab-on-Chip technologies for advanced Point-of-Care molecular diagnostics2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Infectious diseases pose a serious threat to global health. Molecular diagnostics provide solutions for effective control and prevention of infections, however suffers from expensive laboratory equipment, and infrastructure to be fully implemented at point of care (POC), especially at low-resource settings. Lab-on-a-chip that aims to integrate complex biochemical analyses into automated systems is promising for POC analysis. A major challenge is the integration of a complete molecular diagnostic assay, generally translating into complex microfluidics, with the requirement of low fabrication cost. This thesis explores the use of flexible electronics, plastic foils and roll-to-roll manufacturing to enable low-cost microfluidic systems, for molecular diagnostic assays especially targeted towards infectious diseases. Many biochemical assays rely on heat; hence a first aspect in this thesis is the integration of a microheater into microfluidics. In a first project a system for SNP-genotyping is presented using solid phase melting curve analysis to discriminate mutations at a single base resolution. Starting with a glass based concept (paper I) which is further developed to a foil based system (paper II), detection of the polymorphism in the neuropeptide Y associated with increased risk of type II diabetes is demonstrated as a proof of principle. Further development and optimization of the microheater concept has enabled roll-to-roll manufacturing compatibility and multiplexing of targets (paper III). A bacterial sub-typing and multiresistance detection in clinical Staphylococcus Aureus samples is demonstrated for applications in infectious diseases diagnostics. Finally, the microheater concept is further developed to enable μPCR (paper IV). Detection of genomic HIV-1 is demonstrated and a portable detection setup based on an LED light source and low cost CMOS camera for detection was developed. A second aspect of this thesis is integration of light sources and optical detection (paper V-VI). A multilayer system integrating an electroluminescent light source, reactive sensor dyes and organic semiconductor transistor for detection is demonstrated. The system could be used for amine detection in gases (paper V). System was made further roll-to-roll compatible. The system uses an external LED light source and a photodetector processed in only one screen printing- and one dispensing step (paper VI). As a proof of principle, absorbance based DNA hybridization was detected. Collectively, roll-to-roll manufacturing compatible “lab on foil” systems have the potential to improve our ability to diagnose at POC especially at resource-limited settings.

  • 145. Okamura, Allison M.
    et al.
    Mataric, Maja J.
    Christensen, Henrik I.
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS. KTH, School of Computer Science and Communication (CSC), Numerical Analysis, NA.
    Medical and Health-Care Robotics Achievements and Opportunities2010In: IEEE robotics & automation magazine, ISSN 1070-9932, E-ISSN 1558-223X, Vol. 17, no 3, p. 26-37Article in journal (Refereed)
  • 146.
    Orhan, Ibrahim
    et al.
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Gonga, Antonio
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Lindh, Thomas
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    An End-to-End Performance Meter for Applications in Wireless Body Sensor Networks2008In: 2008 5th International Summer School and Symposium on Medical Devices and Biosensors, Institute of Electrical and Electronics Engineers (IEEE), 2008, p. 295-298Conference paper (Refereed)
    Abstract [en]

    This paper presents a monitoring method and its implementation as a light-weight end-to-end performance meter for quality-demanding applications in wireless body sensor networks. The method is evaluated in a wireless sensor network testbed for healthcare applications.

  • 147.
    Orhan, Ibrahim
    et al.
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Lindh, Thomas
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Measurement-based admission control in wireless sensor networks2010In: 2010 Eleventh International Conference on Mobile Data Management (MDM), IEEE , 2010, p. 426-431Conference paper (Refereed)
    Abstract [en]

    Wireless sensor networks have today emerged as a feasible infrastructure for healthcare applications. This paper addresses the non-trivial performance problems in contentionbased wireless networks. We present a method for admission control in contention-based networks, implemented as a component of a performance management system. The test results show that admission control can improve the predictability and level of performance in wireless sensor networks. The system can be used as a tool for dimensioning and configuration as well as for real-time admission control. The often unpredictable dynamics in contention-based access networks means that continuous performance control is needed to maintain a desired quality of service.

  • 148.
    Orhan, Ibrahim
    et al.
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Lindh, Thomas
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Measurement-Based Admission Control in Wireless Sensor Networks2010In: 2010 FOURTH INTERNATIONAL CONFERENCE ON SENSOR TECHNOLOGIES AND APPLICATIONS (SENSORCOMM), IEEE , 2010, p. 447-452Conference paper (Refereed)
    Abstract [en]

    Wireless sensor networks have today emerged as a feasible infrastructure for healthcare applications. This paper addresses the non-trivial performance problems in contention-based wireless networks. We present a method for admission control in contention-based networks, implemented as a component of a performance management system. The test results show that admission control can improve the predictability and level of performance in wireless sensor networks. The system can be used as a tool for dimensioning and configuration as well as for real-time admission control. The often unpredictable dynamics in contention-based access networks means that continuous performance control is needed to maintain a desired quality of service.

  • 149.
    Orhan, Ibrahim
    et al.
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Lindh, Thomas
    KTH, School of Technology and Health (STH), Data- och elektroteknik (Closed 20130701).
    Measurement-Based Performance and Admission Controlin Wireless Sensor Networks2011In: The International Journal on Advances in Systems and Measurement, ISSN 1942-261x, Vol. 4, no 1-2, p. 32-45Article in journal (Refereed)
    Abstract [en]

    This journal paper presents a measurement-basedperformance management system for contention-based wireless sensor networks. Its main features are admission andperformance control based on measurement data from lightweight performance meters in the endpoints. Test results showthat admission and performance control improve the predictability and level of performance. The system can also be used asa tool for dimensioning and configuration of services in wireless sensor networks. Among the rapidly emerging services inwireless sensor networks we focus on healthcare applications

  • 150. Orlova, Anna
    et al.
    Tran, Thuy A.
    Ekblad, Torun
    KTH, School of Biotechnology (BIO), Molecular Biotechnology.
    Eriksson Karlström, Amelie
    KTH, School of Biotechnology (BIO), Molecular Biotechnology.
    Tolmachev, Vladimir
    Re-186-maSGS-Z(HER2:342), a potential Affibody conjugate for systemic therapy of HER2-expressing tumours2010In: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 37, no 2, p. 260-269Article in journal (Refereed)
    Abstract [en]

    Affibody molecules are a novel class of tumour-targeting proteins, which combine small size (7 kDa) and picomolar affinities. The Affibody molecule Z(HER2:342) has been suggested for imaging of HER2 expression in order to select patients for trastuzumab therapy. When optimizing chelators for Tc-99m-labelling, we have found that synthetic Z(HER2:342) conjugated with mercaptoacetyl-glycyl-glycyl-glycyl (maGGG) and mercaptoacetyl-glycyl-seryl-glycyl (maGSG) chelators provides relatively low renal uptake of radioactivity and could be suitable for therapy. maGGG-Z(HER2:342) and maGSG-Z(HER2:342) were labelled with Re-186 and their biodistribution was studied in normal mice. Dosimetric evaluation and tumour targeting to HER2-overexpressed xenografts (SKOV-3) by Re-186-maGSG-Z(HER2:342) were studied. Gluconate-mediated labelling of maGGG-Z(HER2:342) and maGSG-Z(HER2:342) with Re-186 provided a yield of more than 95% within 60 min. The conjugates were stable and demonstrated specific binding to HER2-expressing SKOV-3 cells. Biodistribution in normal mice demonstrated rapid blood clearance, low accumulation of radioactivity in the kidney and other organs, accumulating free perrhenate. Both Re-186-maGGG-Z(HER2:342) and Re-186-maGSG-Z(HER2:342) demonstrated lower renal uptake than their Tc-99m-labelled counterparts. Re-186-maGSG-Z(HER2:342) provided the lowest uptake in healthy tissues. Biodistribution of Re-186-maGSG-Z(HER2:342) in nude mice bearing SKOV-3 xenografts showed specific targeting of tumours. Tumour uptake 24 h after injection (5.84 +/- 0.54%ID/g) exceeded the concentration in blood by more than 500-fold, and uptake in kidneys by about 8-fold. Preliminary dosimetric evaluation showed that dose-to-tumour should exceed dose-to-kidney by approximately 5-fold. Optimization of chelators improves biodistribution properties of rhenium-labelled small scaffold proteins and enables selection of promising radiotherapeutic agents based on the Affibody molecule.

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