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• 1.
KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
Evaluation of head response to ballistic helmet impacts, using FEM2003Conference paper (Refereed)
• 2.
KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701). KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
Proposed global injury thresholds for oblique helmet impacts2003Conference paper (Refereed)
• 3.
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)

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.

KTH, School of Technology and Health (STH). KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Ergonomics. KTH, School of Technology and Health (STH). KTH, School of Technology and Health (STH). KTH, School of Technology and Health (STH).
Big Data & Wearable Sensors Ensuring Safety and Health @Work2017In: GLOBAL HEALTH 2017, The Sixth International Conference on Global Health Challenges, 2017Conference paper (Refereed)

—Work-related injuries and disorders constitute a major burden and cost for employers, society in general and workers in particular. We@Work is a project that aims to develop an integrated solution for promoting and supporting a safe and healthy working life by combining wearable technologies, Big Data analytics, ergonomics, and information and communication technologies. The We@Work solution aims to support the worker and employer to ensure a healthy working life through pervasive monitoring for early warnings, prompt detection of capacity-loss and accurate risk assessments at workplace as well as self-management of a healthy working life. A multiservice platform will allow unobtrusive data collection at workplaces. Big Data analytics will provide real-time information useful to prevent work injuries and support healthy working life

• 5.
KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Karolinska Institutet, Sweden.
KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. University of Borås, Sweden. KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging. Karolinska Institutet, Sweden. 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)

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.

• 6.
KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
Elimination of ECG Artefacts in Foetal EEG Using Ensemble Average Subtraction and Wavelet Denoising Methods: A Simulation2014In: XIII Mediterranean Conference on Medical and Biological Engineering and Computing 2013, Springer, 2014, p. 551-554Conference paper (Refereed)

Biological signals recorded from surface electrodes contain interference from other signals which are not desired and should be considered as noise. Heart activity is especially present in EEG and EMG recordings as a noise. In this work, two ECG elimination methods are implemented; ensemble average subtraction (EAS) and wavelet denoising methods. Comparison of these methods has been done by use of simulated signals achieved by adding ECG to neonates EEG. The result shows successful elimination of ECG artifacts by using both methods. In general EAS method which remove estimate of all ECG components from signal is more trustable but it is also harder for implementation due to sensitivity to noise. It is also concluded that EAS behaves like a high-pass filter while wavelet denoising method acts as low-pass filter and hence the choice of one method depends on application.

• 7.
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)

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.

• 8.
-.
-. -. -. -. -. -. -. -. -. KTH, Superseded Departments, Physics.
K0â KÌ0 transitions monitored by strong interactions: a new determination of the K L–K S mass difference2001In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 503, no 1, p. 49-57Article in journal (Refereed)

The CPLEAR set-up (modified) has been used to determine the KL–KS mass difference by a method where neutral-kaon strangeness oscillations are monitored through kaon strong interactions, rather than semileptonic decays, thus requiring no assumptions on CPT invariance for the decay amplitudes. The result, Δm=(0.5343±0.0063stat±0.0025syst)×1010ℏ/s, provides a valuable input for CPT tests.

• 9.
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Health Informatics.
Samverkan för innovation: En fallstudie av mötet mellan akademi, industri och sjukvård2018Doctoral thesis, monograph (Other academic)

Samverkan kan leda till innovation, konkurrenskraftiga företag, förstklassig forskning samt välfungerande myndigheter och institutioner. I den politiska debatten idag finns en förväntan att Sverige ska upprätthålla sin konkurrenskraft och bemöta samhällets utmaningar genom innovation och att vägen till innovation går via samverkan. Avhandlingen bygger på en studie av ett samverkansprojekt vars syfte var att skapa innovation för att minska antalet vårdrelaterade infektioner i Sverige. Projektet som studerats ses som en transdisciplinär ansats med aktörer som representerade akademi, industri samt hälso- och sjukvård.

Syftet med avhandlingen är att vidareutveckla kunskapen om interorganisatorisk samverkan för innovation. Detta görs genom ett tredelat bidrag, till teoribildningen kring samverkan för innovation som börjat växa fram, till den samverkande praktiken inom både privat och offentlig sektor samt till politiker och beslutsfattare som styr fördelning av statliga anslag till forskning och innovation.

Fallstudien som ligger till grund för avhandlingen är baserad på en etnografiskt inspirerad studie. Empiriskt material samlades in och skapades tillsammans med aktörerna i projektet under drygt två års tid genom intervjuer och deltagande observation.

Studien visar att interorganisatorisk samverkan består av flera dimensioner och kan förstås på flera nivåer. Interorganisatorisk samverkan innebär inte bara att det är olika organisationer som ska göra en gemensam ansträngning. Organisationerna består av olika människor med olika discipliner och professioner vilka bygger på olika utgångspunkter och sätt att se på världen. Samverkan kan ses som ett sätt att fylla mellanrummen mellan organisationer istället för att bygga broar över gränser. I de organisatoriska mellanrummen kan aktörer från olika organisationer, med olika discipliner och professioner mötas utan institutionaliserade roller, i en receptiv kontext där innovation kan skapas.

• 10. Belfrage, Sara
Without informed consent2013In: Moral, Ethical, and Social Dilemmas in the Age of Technology: Theories and Practice, IGI Global, 2013, p. 291-305Chapter in book (Other academic)

The requirement of always obtaining participants' informed consent in research with human subjects cannot always be met, for a variety of reasons. This paper describes and categorises research situations where informed consent is unobtainable. Some of these kinds of situations, common in biomedicine and psychology, have been previously discussed, whereas others, for example, those more prevalent in infrastructure research, introduce new perspectives. The advancement of new technology may lead to an increase in research of these kinds. The paper also provides a review of methods intended to compensate for lack of consent, and their applicability and usefulness for the different categories of situations are discussed. The aim of this is to provide insights into one important aspect of the question of permitting research without informed consent, namely, how well that which informed consent is meant to safeguard can be achieved by other means.

• 11.
KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
STED microscopy: increased resolution for medical research?2014In: Journal of Internal Medicine, ISSN 0954-6820, E-ISSN 1365-2796, Vol. 276, no 6, p. 560-578Article, review/survey (Refereed)

Optical imaging is crucial for addressing fundamental problems in all areas of life science. With the use of confocal and two-photon fluorescence microscopy, complex dynamic structures and functions in a plethora of tissue and cell types have been visualized. However, the resolution of classical' optical imaging methods is poor due to the diffraction limit and does not allow resolution of the cellular microcosmos. On the other hand, the novel stimulated emission depletion (STED) microscopy technique, because of its targeted on/off-switching of fluorescence, is not hampered by a diffraction-limited resolution barrier. STED microscopy can therefore provide much sharper images, permitting nanoscale visualization by sequential imaging of individual-labelled biomolecules, which should allow previous findings to be reinvestigated and provide novel information. The aim of this review is to highlight promising developments in and applications of STED microscopy and their impact on unresolved issues in biomedical science.

• 12.
KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
Recirculation during veno-venous extra-corporeal membrane oxygenation: a simulation study2015In: International Journal of Artificial Organs, ISSN 0391-3988, E-ISSN 1724-6040, Vol. 38, no 1, p. 23-30Article in journal (Refereed)

PURPOSE:

Veno-venous ECMO is indicated in reversible life-threatening respiratory failure without life-threatening circulatory failure. Recirculation of oxygenated blood in the ECMO circuit decreases efficiency of patient oxygen delivery but is difficult to measure. We seek to identify and quantify some of the factors responsible for recirculation in a simulation model and compare with clinical data.

METHODS:

A closed-loop real-time simulation model of the cardiovascular system has been developed. ECMO is simulated with a fixed flow pump 0 to 5 l/min with various cannulation sites - 1) right atrium to inferior vena cava, 2) inferior vena cava to right atrium, and 3) superior+inferior vena cava to right atrium. Simulations are compared to data from a retrospective cohort of 11 consecutive adult veno-venous ECMO patients in our department.

RESULTS:

Recirculation increases with increasing ECMO-flow, decreases with increasing cardiac output, and is highly dependent on choice of cannulation sites. A more peripheral drainage site decreases recirculation substantially.

CONCLUSIONS:

Simulations suggest that recirculation is a significant clinical problem in veno-venous ECMO in agreement with clinical data. Due to the difficulties in measuring recirculation and interpretation of the venous oxygen saturation in the ECMO drainage blood, flow settings and cannula positioning should rather be optimized with help of arterial oxygenation parameters. Simulation may be useful in quantification and understanding of recirculation in VV-ECMO.

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

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

• 14.
University of Borås, Sweden.
Technical University of Catalonia. Technical University of Catalonia. KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
Influence of electrode mismatch on Cole parameter estimation from Total Right Side Electrical Bioimpedance Spectroscopy measurements2012In: Medical Engineering and Physics, ISSN 1350-4533, E-ISSN 1873-4030, Vol. 34, no 7, p. 1024-1028Article in journal (Refereed)

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

• 15.
KTH, School of Technology and Health (STH).
Clinicians' demands on monitoring support in an Intensive Care Unit: A pilot study, at Capio S:t Görans Hospital2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis

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

• 16. Capece, Sabrina
KTH, School of Technology and Health (STH), Medical Engineering, Medical Imaging.
A general strategy for obtaining biodegradable polymer shelled microbubbles as theranostic devices2013In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 49, no 51, p. 5763-5765Article in journal (Refereed)

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

• 17.
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Medical Imaging.
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Medical Imaging. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Medical Imaging. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems, Medical Imaging.
Polymer Microbubbles as Dual Modal Contrast Agent for Ultrasound and Computed Tomography2018Conference paper (Refereed)

The hybrid imaging combines the anatomical information with the functional or metabolic information using different conventional single imaging modalities improving the overall diagnosis outcome of the clinical examination. Since the introduction of the first hybrid imaging device PET-CT in 1998 different combinations of hybrid imaging were developed such as PET-MRI, SPECT-CT.

However, lack of multimodal contrast agent specifically aimed for hybrid imaging limits the diagnostic outcome of these novel techniques. Initial attempts in fabrication of hybrid contrast agents were made by combining previously existing single modal contrast agents into one. In this study, polyvinyl alcohol (PVA) microbubbles (MB) and gold nanoparticles - which by themselves are already established contrast agents used in preclinical studies for ultrasound and CT, respectively - were chosen as parent contrast agents to fabricate the dual modal Contrast Agent for UltraSound and CT (CACTUS).

Method

The fabrication of MBs was adapted from Cavalieri et al.[1]. PVA powder (Sigma Aldrich, MO USA) was dissolved in the water at 80°C. The aqueous PVA-chains were cleaved by sodium metaperiodate (NaIO4, purity>99.0%, Sigma Aldrich, MO USA). Vigorous stirring force was applied to the resulting telechelic aldehydic PVA-chains for 2 hours to crosslink the telechelic aldehydic PVA-chains and form the PVA-coated MBs at the water-air interface.

CACTUS MBs were synthesized in a similar fashion to the above, but adding gold nanoparticles (diameter 1.9nm, Nanoprobes, NY, USA) during formation of the MBs.

The size distributions of MBs and CACATUS MBs were determined using an optical microscope (ECLIPSE Ci-S, Nikon, Tokyo, Japan) and a Neubauer counting chamber (Brand GmbH, Wertheim, Germany).

The acoustic attenuation coefficients of the MBs suspension were acquired at peak negative pressure (PNP) from 10 - 300 kPa. Three MBs suspension samples with concentrations of (sample A),  (sample B) and  ml-1 (sample C) were prepared and loaded in a 1 cm thick two-cavity chamber. A flat single crystal ultrasound transducer with central frequency 3.5MHz was used to generate the ultrasound beam. The amplitude of received echoes through samples and water were compared at the fundamental frequency, as well as the 2nd and 3rd harmonic for each value of the concentration used.

The mass attenuation of water, suspension of gold nanoparticles with concentration 160mg/L, plain MBs, and CACTUS MBs, was measured by quantum FX-CT micro-CT (PerkinElmer Inc, MA, USA). The micro-CT was operated at a current of 200mA with exposure time of 120s and varied voltage 50kV, 70kV and 90kV. Each 3D image has a size of 512*512*512 pixels or 75.8*75.8*75.8 mm. Contrast to noise ratios (CNR) between water and all samples were calculated following Eq. 1.$CNR=\frac{Singal difference}{Noise}=\frac{\int_{}^{}S(x,y,z)+ns(x,y,z)-W(x,y,z)-nw(x,y,z)dxdydz}{\sqrt[]{\int_{}^{}\frac{1}{2}dxdydz}}=\sqrt[]{N}*\frac{M_{s}-M_{w}}{\sqrt[]{\frac{1}{2}sigma_{\sigma_{s}^{2}+\sigma_{w}^{2}})}}=\sqrt[]{N}* CNR per voxel$Where S(x,y,z) and W(x,y,z) are the mass attenuation of the sample and water per voxel, respectively. ns(x,y,z) and nw(x,y,z) are the noise function with zero mean of sample and water respectively. Ms and Mw are the mean mass attenuation acquired for the sample and water in the volume of interest. The σs2 and σw2 are the variance of the mass attenuation read out of the sample and water in the volume of interested.

In addition to the gas-core MBs for the CT tests, liquid-core gold loaded capsules were synthesized in two steps. In the first step, PVA shelled liquid-core capsules were obtained by exposing MBs to 66% v/v ethanol solution. In the second step, the resulting liquid-core capsules were mixed with high concentration gold nanoparticles suspension and homogenized by a shaker (MS 3 basic, IKA, Königswinter Germany) at 500rpm for 1 hour for goal loading. The resulting gold loaded capsules were washed with Milli-Q water using centrifuge (Galaxy 5D digital microcentrifuge, VWR, USA) at a speed of 1000 g for 5 min.

Results and discussion

The mean diameter of MBs is 3.6±1.1 μm. The mean diameter of CACTUS MBs is 3.2±0.7 μm. The size distribution of the gold loaded capsules was not investigated separately, but rather assumed identical to the plain MBs. The number and the volume distribution of MBs and CACTUS MBs are shown in figure 1. The results demonstrate that most of the CACTUS MBs and MBs have a diameter from 1 to 6 μm. Therefore, they are able pass through the capillaries and will resonate within typical clinical diagnostic ultrasound frequency below 15 MHz.

Pressure dependent acoustic attenuation coefficients of the sample A, B, and C are shown in figure 2. The results show that attenuation coefficients of sample A and B at the fundamental frequency stay constant and slightly increase at the second harmonic at the PNP below 100kPa, indicating a linear oscillation of MBs. As the PNP reaches 200kPa, the attenuation coefficient of sample A at fundamental frequency decreases while at 2nd and 3rd harmonics increases, indicating that the energy of the echo shifts from the fundamental frequency to the 2nd and 3rd harmonics. As the PNP goes higher to 300kPa, the attenuation coefficient of sample A at the fundamental frequency, 2nd, and 3rd harmonics decreases, suggesting that the energy shifts to an even higher harmonic. At the same time, the attenuation coefficient of sample B stays constant at fundamental frequency, decreases at 2nd harmonics, and increases at the 3rd harmonic, suggesting the energy starts to shift to the 3rd harmonic. The attenuation coefficient of sample C at fundamental frequency, 2nd and 3rd harmonics keep constant and low due to low sample concentration. The test reveals the energy shifting of the echo to the higher harmonics at PNP higher than 100 kPa, indicating the nonlinear oscillation of MBs at PNP higher than 100 kPa. Moreover, the concentration of the MBs seems to influence the energy shifting: the higher the concentration the earlier the shift to the higher harmonics occurs, in the range of the concentration consider in this study.

The pilot results of the micro-CT tests are presented in Table 1. The reference, gold nanoparticles solution, has the highest CNR per voxel at all CT operating voltages. The CNR per voxel of CACTUS MBs suspensions is below 0.1, virtually equaling the MBs at all operating voltages, suggesting that no gold or very little gold were loaded into the shell of the CACTUS MBs. The gold loaded capsules suspension has higher CNR per voxel than the capsule supernatant (the surrounding environment of capsules) and the MBs suspension, implying that the gold nanoparticles were loaded into the capsules. However, it is not clear whether the gold nanoparticles were loaded in the core of the MBs or in the MBs shell. The expected sharp increase of CNR per voxel at the k-edge of gold did not appear. We believe that is because even at our highest operating voltage of 90kV, the percentage of the photons with energy higher than 80.7 keV is still low. Introduction of a high-pass metal filter could increase the percentage of high energy photon. On the other hand, the metal filter will reduce the total number of the photons which would increase the noise of the images. Since same current was applied on every CT test, less X-ray photons reached the sensors when the CT was operated at low voltage. Therefore, it might be worth performing additional calibration tests to adjust the operating currents to make sure that the numbers of the photons that reach the sensor at every operating voltage are the same.

Conclusion

In this study, the CACTUS MBs and gold loaded capsules were fabricated as potential candidates for dual modal contrast agent. The characterization revealed that gold loaded capsule is a promising initial step. Nevertheless, the method to convert back liquid-core capsules to gas-core MBs needs to be established.

[1] Cavalieri, F., El Hamassi, A., Chiessi, E., Paradossi, G., Villa, R., & Zaffaroni, N. (2006). Tethering functional ligands onto shell of ultrasound active polymeric microbubbles. Biomacromolecules, 7(2), 604-611.

• 18.
Eindhoven University of Technology, Department of Mechanical Engineering.
Eindhoven University of Technology, Department of Mechanical Engineering. KTH, School of Technology and Health (STH), Neuronic Engineering. Eindhoven University of Technology, Department of Mechanical Engineering.
Multi-scale mechanics of traumatic brain injury: predicting axonal strains from head loads2013In: Biomechanics and Modeling in Mechanobiology, ISSN 1617-7959, E-ISSN 1617-7940, Vol. 12, no 1, p. 137-150Article in journal (Refereed)

The length scales involved in the development of diffuse axonal injury typically range from the head level (i.e., mechanical loading) to the cellular level. The parts of the brain that are vulnerable to this type of injury are mainly the brainstem and the corpus callosum, which are regions with highly anisotropically oriented axons. Within these parts, discrete axonal injuries occur mainly where the axons have to deviate from their main course due to the presence of an inclusion. The aim of this study is to predict axonal strains as a result of a mechanical load at the macroscopic head level. For this, a multi-scale finite element approach is adopted, in which a macro-level head model and a micro-level critical volume element are coupled. The results show that the axonal strains cannot be trivially correlated to the tissue strain without taking into account the axonal orientations, which indicates that the heterogeneities at the cellular level play an important role in brain injury and reliable predictions thereof. In addition to the multi-scale approach, it is shown that a novel anisotropic equivalent strain measure can be used to assess these micro-scale effects from head-level simulations only.

• 19.
Eindhoven University of Technology, Department of Mechanical Engineering.
Eindhoven University of Technology, Department of Mechanical Engineering. KTH, School of Technology and Health (STH), Neuronic Engineering. Eindhoven University of Technology, Department of Mechanical Engineering.
Traumatic Brain Injury at Multiple Length Scales: Relating Diffuse Axonal Injury to Discrete Axonal Impairment2010In: 2010 INTERNATIONAL IRCOBI CONFERENCE ON THE BIOMECHANICS OF INJURY PROCEEDINGS, 2010, p. 119-130Conference paper (Refereed)
• 20.
Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
KTH, School of Technology and Health (STH), Medical Engineering, Neuronic Engineering. KTH, School of Technology and Health (STH), Medical Engineering, Neuronic Engineering. Department of Psychology, Umeå University, Umeå, Sweden. Department of Computer and Systems Sciences, Stockholm University, Stockholm, Sweden. KTH, School of Technology and Health (STH), Medical Engineering, Neuronic Engineering. Department of Clinical Science, Intervention and Technology, Division of Orthopaedics and Biotechnology, Karolin-ska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden. Department of Clinical Science, Intervention and Technology, Division of Orthopaedics and Biotechnology, Karolin-ska Institutet, Karolinska University Hospital, Huddinge, Stockholm, Sweden.
Learning through a virtual patient vs. recorded lecture: a comparison of knowledge retention in a trauma case2018In: International Journal of Medical Education, ISSN 2042-6372, E-ISSN 2042-6372, Vol. 9, p. 86-92Article in journal (Refereed)

Objectives: To compare medical students' and residents' knowledge retention of assessment, diagnosis and treatment procedures, as well as a learning experience, of patients with spinal trauma after training with either a Virtual Patient case or a video-recorded traditional lecture. Methods: A total of 170 volunteers (85 medical students and 85 residents in orthopedic surgery) were randomly allocated (stratified for student/resident and gender) to either a video-recorded standard lecture or a Virtual Patient-based training session where they interactively assessed a clinical case portraying a motorcycle accident. The knowledge retention was assessed by a test immediately following the educational intervention and repeated after a minimum of 2 months. Participants' learning experiences were evaluated with exit questionnaires. A repeated-measures analysis of variance was applied on knowledge scores. A total of 81% (n = 138) of the participants completed both tests. Results: There was a small but significant decline in first and second test results for both groups (F-(1,F-135) = 18.154, p = 0.00). However, no significant differences in short-term and long-term knowledge retention were observed between the two teaching methods. The Virtual Patient group reported higher learning experience levels in engagement, stimulation, general perception, and expectations. Conclusions: Participants' levels engagement were reported in favor of the VP format. Similar knowledge retention was achieved through either a Virtual Patient or a recorded lecture.

• 21.
KTH, School of Technology and Health (STH). Philips Research Europe, High Tech. Campus 34, 5656AE, Eindhoven, Netherlands; ACTLab., Signal Processing Systems, TU Eindhoven, 5600MB Eindhoven, Netherlands.
Philips Research Europe, High Tech. Campus 34, 5656AE, Eindhoven, Netherlands. KTH, School of Technology and Health (STH). KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. University of Borås, Sweden. KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Karolinska Institute, Sweden. ACTLab., Signal Processing Systems, TU Eindhoven, 5600MB Eindhoven, Netherlands.
Removing respiratory artefacts from transthoracic bioimpedance spectroscopy measurements2013In: XV International Conference on Electrical Bio-Impedance (ICEBI) & XIV Conference on Electrical Impedance Tomography (EIT), Institute of Physics Publishing (IOPP), 2013, Vol. 434, no 1Conference paper (Refereed)

Transthoracic impedance spectroscopy (TIS) measurements from wearable textile electrodes provide a tool to remotely and non-invasively monitor patient health. However, breathing and cardiac processes inevitably affect TIS measurements, since they are sensitive to changes in geometry and air or fluid volumes in the thorax. This study aimed at investigating the effect of respiration on Cole parameters extracted from TIS measurements and developing a method to suppress artifacts. TIS data were collected from 10 participants at 16 frequencies (range: 10 kHz - 1 MHz) using a textile electrode system (Philips Technologie Gmbh). Simultaneously, breathing volumes and frequency were logged using an electronic spirometer augmented with data from a breathing belt. The effect of respiration on TIS measurements was studied at paced (10 and 16 bpm) deep and shallow breathing. These measurements were repeated for each subject in three different postures (lying down, reclining and sitting). Cole parameter estimation was improved by assessing the tidal expiration point thus removing breathing artifacts. This leads to lower intra-subject variability between sessions and a need for less measurements points to accurately assess the spectra. Future work should explore algorithmic artifacts compensation models using breathing and posture or patient contextual information to improve ambulatory transthoracic impedance measurements.

• 22.
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems.
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Biomedical Engineering and Health Systems.
Utveckling av en applikation för rullstolsflödet på Karolinska Universitetssjukhuset i Solna2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis

I dagens samhälle har spårbarhet av medicintekniska hjälpmedel fått en allt viktigare innebörd inom sjukvården. En anledning till det är att de flesta hjälpmedel klassas som medicintekniska produkter vilka enligt Socialstyrelsens föreskrifter måste kunna spåras. Därför märks många hjälpmedel med streckkoder eller liknande markörer. På Karolinska Universitetssjukhuset i Solna önskar man förbättra spårbarheten av rullstolar och få en bättre översikt över vilka som är utlånade och förskrivna.

En metod för att lösa detta problem är genom att digitalisera flödesprocessen för rullstolar. I det här arbetet har ett digitalt program utvecklats för att ersätta ett antal steg i flödesprocessen som i nuläget hanteras manuellt med penna och papper. Genom att digitalisera delar av processen och se över möjligheter att implementera scanners kan informationen kvalitetssäkras och arbetet effektiviseras. Resultatet visar att ett sådant program som det som utvecklades skulle vara gynnsamt för sjukhuset och skulle bidra till en bättre kontroll över rullstolsflödet. I och med arbetet har en god grund lagts för att digitalisera hanteringen av hjälpmedel och utveckla processerna.

• 23.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology. KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, School of Engineering Sciences (SCI), Applied Physics. KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
Development of a novel microfluidic device for long-term in situ monitoring of live cells in 3-dimensional matrices2012In: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781, Vol. 14, no 5, p. 885-893Article in journal (Refereed)

Using the latest innovations in microfabrication technology, 3-dimensional microfluidic cell culture systems have been developed as an attractive alternative to traditional 2-dimensional culturing systems as a model for long-term microscale cell-based research. Most microfluidic systems are based on the embedding of cells in hydrogels. However, physiologically realistic conditions based on hydrogels are difficult to obtain and the systems are often too complicated. We have developed a microfluidic cell culture device that incorporates a biodegradable rigid 3D polymer scaffold using standard soft lithography methods. The device permits repeated high-resolution fluorescent imaging of live cell populations within the matrix over a 4 week period. It was also possible to track cell development at the same spatial location throughout this time. In addition, human primary periodontal ligament cells were induced to produce quantifiable calcium deposits within the system. This simple and versatile device should be readily applicable for cell-based studies that require long-term culture and high-resolution bioimaging.

• 24.
KTH, School of Technology and Health (STH), Neuronic Engineering.
Mechanical Engineering Department, Biomechanics Section, Katholieke Universiteit Leuven, Belgium. KTH, School of Technology and Health (STH), Neuronic Engineering. Mechanical Engineering Department, Biomechanics Section, Katholieke Universiteit Leuven, Belgium. Mechanical Engineering Department, Biomechanics Section, Katholieke Universiteit Leuven, Belgium. Mechanical Engineering Department, Biomechanics Section, Katholieke Universiteit Leuven, Belgium. KTH, School of Technology and Health (STH), Neuronic Engineering.
Influence of impact velocity and angle in a detailed reconstruction of a bicycle accident2012In: 2012 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury, 2012, p. 787-799Conference paper (Refereed)

Bicycle accidents have become the most common cause of serious injury in the traffic during the last couple of years in Sweden. The objective of this study was to investigate the effect of the input variables, initial velocity and head orientation, of a bicycle accident reconstruction on the strain levels in the brain using a detailed FE head model. The accident involved a non-helmeted 68 year old male who sustained a linear skull fracture, contusions, acute subdural hematoma, and small bleeding at the swelling (subarachnoid blood). The orientation of the head just before impact was determined from the swelling appearing in the computer tomography (CT) scans. The head model used in this study was developed at the Royal Institute of Technology in Stockholm. The stress in the cranial bone, first principal strain in the brain tissue and acceleration were determined. The model was able to predict a strain pattern that correlated well with the medical images from the victim. The variation study showed that the tangential velocity had a large effect on the strain levels in the studied case. The strain pattern indicated larger areas of high strain with increased tangential velocity especially at the more superior sections.

• 25.
KTH, School of Technology and Health (STH), Medical Engineering.
Effect of side windows, stiffening plate and roof sheet on the stiffness of the bus body2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis

As a bus developer, Scania focus to construct a safe vehicle for the passengers, i.e. high strength of the bus structure and good comfort, which is also profitable for the operator, i.e. high passenger capacity and low fuel consumption. The trade-off when developing a bus body structure is to get both high stiffness and low weight. The bus body including exterior panels plays together with the chassis an important role for the stiffness of the bus. By gathering knowledge about how various exterior panels affects the stiffness of the bus body, the design of the panels can be optimized with respect to high stiffness and low weight. Also from a calculation point of view is it of interest to know how important different panels are for the stiffness of the bus body, in order to make conscious simplifications in the calculation model.

The aim with this master thesis was to investigate how the stiffening plate, side windows and roof sheet influence the strength of the bus body. How the thickness of the side windows affects the stiffness of the bus body is also investigated. The investigations were made as a relative comparison between a complete bus and comparison models.

Thinner side windows are shown to have a positive influence on the stiffness of the bus body.

• 26.
KTH, School of Technology and Health (STH).
KTH, School of Technology and Health (STH).
IT- och informationssäkerhet inom prehospital vård: Kommunikation mellan ambulans och sjukhus inom Stockholms Läns Landsting och Region Kronoberg2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis

Prehospital care is an important part of the Swedish health system, the care process is dedicated to any kind of emergency out-of-hospital acute medical care. The quality of prehospital care varies between different counties, depending on their technical equipment and work methods. This essay investigates how Region Kronoberg (RK) and Stockholm’s County Council (SLL) have dealt with IT- and information security questions concerning prehospital care.

The essay is conducted by collecting laws and guidelines related to IT-security. Interviews were later on conducted with intention to collect information about RK’s and SLL’s definition of accessibility and communication of patient journals

This essay shows that RK and SLL begun digitizing their prehospital care at different times, but that they are as in now able to use equally safe methods for dealing with journals. The reason behind this is that they both root their solutions in the secluded network Sjunet. It is further concluded that SLL and RK have different prerequisites for journal access. Lastly, we could conclude that the greatest security risk is not associated with the connection between hardware, but rather misplacing any hardware containing delicate information.

• 27.
KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS). KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
AD5933-based electrical bioimpedance spectrometer: Towards textile-enabled applications2011In: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 2011, Vol. 2011, p. 3282-3285Conference paper (Refereed)

Advances on System-On-Chip and Textile technology allows the development of Textile-enabled measurement instrumentation. Textile Electrodes (Textrodes) have been proven reliable for performing Electrical Bioimpedance Spectroscopy (EBIS) measurements, and the availability of a integrated circuit impedance spectrometer, the AD5933, has allowed the implementation of small size EBIS spectrometers. In this work an AD5933-based spectrometer has been implemented, and its performance on 2R1C circuits and for tetrapolar total right side EBIS measurements has been compared against the commercially available spectrometer SFB7. The study has been focused on the working upper frequency range and the estimation of the Cole parameters required for assessment of body fluid distribution: R(0) and R(∞). The results indicate that AD5933-based spectrometer implemented in this work can perform accurate impedance measurements well above the upper limits recommended in the datasheet. The AD5933-EBIS presents a good performance compared with the SFB7 on the 2R1C circuit and the total right side measurements, showing a smaller error in the resistance spectrum and small deviation error in the reactance when measuring over 270 kHz. The comparison on the Cole parameters estimation obtained with the SFB7 and the AD5933-based spectrometer exhibit a difference below 1% for the estimation of R(0) and R(∞). Consequently the overall measurement performance shown by the implemented AD5933-based spectrometer suggests its feasible use for EBIS measurements using dry Textrodes. This is of special relevance for the proliferation of EBI-based personalized health monitoring systems for patients that require to monitor the distribution of body fluids, like in dialysis.

• 28.
KTH, School of Technology and Health (STH), Health Systems Engineering, Human Communication Science. Välj.
Medical Technology and eHealth for Prevention against LifestyleRelated Diseases: A survey of attitudes among health center personnel and patients prescribed with physical activity on prescription (PAP)2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis

With an aging population that suffers from comorbidity, healthcare is facing grand challenges. In order to meet the demand, digitalization is thought to be an opportunity. Digitalization of curative care, such as diagnostics and treatment, have been initiated and is today used and appreciated. Preventative care, on the other hand, has not been included in the digital adaptions to the same extent and there are few scientific studies within the area. Nonetheless, a further proactive care that meets patients and healthcare personnel are of interest to several actors. The Swedish Government has a vision that Sweden, in 2025, will be world leading within eHealth. For that to be possible, digital preventative care have to support and complete the preventative work that is performed today.

The present study has investigated the attitude towards Connected Medical Devices for Prevention (CMDfP) within the primary care. By a mixed-methodology including questionnaires, the opinions of 24 health center personnel and 17 patients prescribed with Physical Activity on Prescription (PAP) were collected and analyzed. The results show that health center personnel are willing to prescribe connected eHealth devices for prevention and patients are willing to use the devices prescribed. Additionally, among the respondents there is a belief that CMDfP could facilitate in order to increase the adherence to PAP without any major impact on the personnel's workload.

By digitalizing preventative care, it is possible that people will be able to live healthier and therefore not require care to the same extent as today. Reasons to the possible results are that digital tools within curative care have been shown to generate positive outcomes to chronically ill patients that utilize home care. Additionally, studies of preventative care have generated positive outcomes to the health of the population in several countries. It is therefore likely that the combination, digital preventative care, would be rapidly relished. These thoughts align with the positive results on attitudes of this study.

Before CMDfP could be prescribed to patients, pilot studies have to be performed and new work routines including reimbursement models, have to be established within healthcare. These are all areas of future work within medical engineering.

• 29.
KTH, School of Computer Science and Communication (CSC), Media Technology and Interaction Design, MID.
KTH, School of Computer Science and Communication (CSC), Media Technology and Interaction Design, MID. KTH, School of Computer Science and Communication (CSC), Media Technology and Interaction Design, MID. KTH, School of Computer Science and Communication (CSC), Media Technology and Interaction Design, MID.
Interaction design in a complex context: medical multi-disciplinary team meetings2012In: The 7th Nordic Conference on Human-Computer Interaction: Making Sense Through Design, New York, NY, USA, 2012, p. 341-350Conference paper (Refereed)

In order to improve collaboration on, and visualisation of, patient information in medical multi-disciplinary team meetings, we have developed a system that presents information from different medical systems to be used as a support for the decision process. Based on field studies, we have implemented a high-fidelity prototype on tablet-sized displays, and tested it in a realistic setting. Our evaluation proved that more patient information can efficiently be displayed to all meeting participants, compared to the current situation. Interaction with the information, on the other hand, proved to be a complicated activity that needs careful design considerations; it should ultimately be based on what roles the meeting participants have, and what tasks they should complete. Medical decision-making is a complex area, and conducting interaction design in this area proved complex too. We foresee a great opportunity to improve medical work, by introducing collaborative tools and visualisation of medical data, but it requires that interaction design becomes a natural part of medical work.

• 30.
KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
Oxygen content in semi-closed rebreathing apparatuses for underwater use: Measurements and modeling2015Doctoral thesis, comprehensive summary (Other academic)

The present series of unmanned hyperbaric tests were conducted in order to investigate the oxygen fraction variability in semi-closed underwater rebreathing apparatuses. The tested rebreathers were RB80 (Halcyon dive systems, High springs, FL, USA), IS-Mix (Interspiro AB, Stockholm, Sweden), CRABE (Aqua Lung, Carros Cedex, France), and Viper+ (Cobham plc, Davenport, IA, USA). The tests were conducted using a catalytically based propene combusting metabolic simulator. The metabolic simulator connected to a breathing simulator, both placed inside a hyperbaric pressure chamber, was first tested to demonstrate its usefulness to simulate human respiration in a hyperbaric situation. Following this the metabolic simulator was shown to be a useful tool in accident investigations as well as to assess the impact of different engineering designs and physiological variables on the oxygen content in the gas delivered to the diver by the rebreathing apparatuses. A multi-compartment model of the oxygen fractions was developed and compared to the previously published single-compartment models. The root mean squared error (RMSE) of the multi-compartment model was smaller than the RMSE for the single-compartment model, showing its usefulness to estimate the impact of different designs and physiological variables on the inspired oxygen fraction.

• 31.
KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
KTH, School of Technology and Health (STH), Basic Science and Biomedicine, Environmental Physiology.
Modeling a demand constant volume ratio exhaust and a self-mixing constant oxygen injection semi-closed rebreatherManuscript (preprint) (Other academic)

Unmanned tests of two types of gas dosage techniques for semi-closed underwater rebreathing apparatuses were carried out with a metabolic simulator in a water filled pressure chamber. Tests were conducted over a wide range of tidal volumes (0.5-3 L), respiratory frequencies (5-25 min-1), and oxygen consumptions (0.5-4 L/min), as well as with changing chamber pressures from 100 kPa to 920 kPa. Two models were set up, one single compartment model and one model assuming multiple serial compartments. Both models seem to have about the same level of accuracy at predicting the inspired oxygen levels at pressure, but the surface tests seem to favor the serial compartments model.

• 32.
KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.).
Aorta2017In: Biomechanics of Living Organs: Hyperelastic Constitutive Laws for Finite Element Modeling, Elsevier, 2017, p. 169-191Chapter in book (Refereed)

The aorta is a dynamic structure that is able to maintain conditions for optimal mechanical operation through the continuous turnover of its internal structure. The aorta's properties are critical to the entire cardiovascular system, and the study of its biomechanics may help us to better understand the role of tissue stress and strain in aortic aging and pathology, help to optimize medical devices, and improve therapeutic and diagnostic methods that are currently used in clinics. The present chapter reviews aortic wall histology and morphology in relation to its key mechanical properties. Specifically, the biomechanical role of cells (endothelial cells, smooth muscle cells, fibroblasts, etc.), as well as the extracellular matrix components (elastin, collagen, proteoglycans, water, etc.), will be discussed. Then this information is related to reported constitutive descriptions for aortic tissues. The focus is on histo-mechanical approaches and modeling frames, related to hyperelasticity as well as a superposition of fiber contributions according to a general theory of fibrous connective tissue. Concluding remarks relate to open problems in aorta biomechanics, such as uncertainty and variability of input information. Remarks are also made on the admissible degree of complexity in aortic simulations, in the context of such uncertainties.

• 33.
KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Entrepreneurship and innovation.
KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Entrepreneurship and innovation.
International market selection: Assessing opportunities in the European Union for a mHealth consumer medical device start-up2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis

To date, there are no existing models for evaluating foreign markets, adapted to mobile health (mHealth) consumer medical device (CMD) start-ups seeking to launch their products or services in new countries. This calls for the development of a suitable international market selection (IMS) model that captures the complexity of and opportunities for mHealth. mHealth is a sub-segment of electronic health (eHealth), which furthermore is part of the wider phenomenon of digital health. mHealth covers medical and public health practice supported by mobile devices.

This paper proposes a multidimensional IMS model comprising both macro and micro level factors. Our specialized approach integrates tools and theories by a number of researchers and is showcased in the assessment of the European Union (EU) for the mHealth CMD company AdhereBox. AdhereBox is a Swedish start-up that has developed a CMD consisting of a “smart” pillbox and a complementary mobile software application.

We propose a number of dimensions that should be evaluated when assessing the potential  of the different EU health care markets in regards to mHealth CMD start-ups. Our suggested approach includes factors which are categorized into two groups of parameters: (i) stakeholders (which comprises consumers, providers, payers, distributors and collaborators) and (ii) barriers & enablers (consisting of incentives, reimbursement models, technological infrastructure, regulations and existing solutions).

In summary, our study identifies critical factors that mHealth CMD start-ups should consider when evaluating foreign markets in an IMS. By applying our IMS model on AdhereBox, we illustrate how our model can be used, its parameters assessed and the interdependencies between these analyzed in order to arrive at a set of recommendations for further market analysis and conclusions on country attractiveness. As such, we believe that our research could provide valuable insights and guidelines for firms within mHealth seeking to expand their business within the EU, as well as for governmental organizations that want to better leverage and stimulate the potentials of a flourishing domestic mHealth ecosystem.

• 34. Granåsen, G.
KTH, School of Technology and Health (STH), Medical Engineering.
Comparison between ultrasonic muscle strain and electromyography during an isometric ramp contraction2010In: World Congress on Medical Physics and Biomedical Engineering, September 7 - 12, 2009, Munich, Germany, Springer Berlin/Heidelberg, 2010, Vol. 25/4, p. 1565-1567Conference paper (Refereed)

This study aims to explore multi modal relationships between ultrasonic muscle strain and electromyography (EMG). Canonical Correlation Analysis (CCA) is technique which can be used to explore multivariate associations between sets of variables. Multi-channel EMG and a spatial differentiated Tissue Velocity Imaging (TVI)-strain signal was compared from measurements on biceps brachii on eight subjects. A data analysis using CCA was then applied to obtain useful information of the relationship between signals.

• 35. Gyarmati, P.
KTH, Centres, Science for Life Laboratory, SciLifeLab.
Metagenomic analysis of bloodstream infections in patients with acute leukemia and therapy-induced neutropenia2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 23532Article in journal (Refereed)

Leukemic patients are often immunocompromised due to underlying conditions, comorbidities and the effects of chemotherapy, and thus at risk for developing systemic infections. Bloodstream infection (BSI) is a severe complication in neutropenic patients, and is associated with increased mortality. BSI is routinely diagnosed with blood culture, which only detects culturable pathogens. We analyzed 27 blood samples from 9 patients with acute leukemia and suspected BSI at different time points of their antimicrobial treatment using shotgun metagenomics sequencing in order to detect unculturable and non-bacterial pathogens. Our findings confirm the presence of bacterial, fungal and viral pathogens alongside antimicrobial resistance genes. Decreased white blood cell (WBC) counts were associated with the presence of microbial DNA, and was inversely proportional to the number of sequencing reads. This study could indicate the use of high-throughput sequencing for personalized antimicrobial treatments in BSIs.

• 36.
KTH, School of Technology and Health (STH).
The Knowledge- and Adoption Level of Standards for Technical Interoperability among Providers of Healthcare Information Systems2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis

This thesis was one of the deliverables of StandIN. The purpose of StandIN was to propose a common framework including standards for technical interoperability. The goal of this thesis was to structure and analyze information about the knowledge- and adoption level of the standards among providers of healthcare information systems (HIS's). Moreover, it aimed to evaluate different aspect that might affect the adoption.

The target group was providers of HIS's used in Swedish county councils and regions. The information was gathered through a survey and semi-structured interviews, and stored in an Excel database. From the database, Pivot tables and charts were created in order to show the knowledge- as well as adoption level of the different standards. The results were thereafter compared to theory about interoperability and standard adoption.

It was clear that the knowledge level varied for the different standards. In addition, the adoption level was very low - except from CCOW and HL7 v2. Least adopted were domain-specific standards. The results also indicated a trend for only adopting parts of standards. Moreover, many providers stated that they performed specific integrations rather than followed common standards. This seemed to be due to the choice of standards being too wide, and the actual adoption not being consistent among the different providers. According to the providers, an introduction of a national framework based on uniform and consistent international standards was an awaited solution to the problem.

A future extension of this thesis would be to perform a similar study involving the customers. The database could also be used to do clustered analyses of the adoption state in different county councils and regions. Moreover, it could be used to analyze the development of standard adoption over time.

• 37.
KTH, School of Technology and Health (STH).
KTH, School of Technology and Health (STH).
Guidelines for smartphone usage in telemedical photography2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis

The wide usage of smartphones makes them an interesting and potential medical device. Given that smartphone cameras have a sufficiently high quality - some of the medical photography done at health care facilities could be done telemedically and by non-medically educated per- sons. Therefore a research of the quality of the photos taken with smartphone cameras has been done. This thesis presents guidelines regarding how inexperienced persons could take high qualitative medical photos with a smartphone.

This thesis includes a review of current guidelines within medical photography. A compari- son between two popular smartphones and a professional medical camera has been done - where possibilities and limitations in smartphone cameras have been identified. In order to evaluate the sharpness and the color temperature representation in the photos taken with smartphones, an experiment with realistic lighting and easy accessible color-calibration cards has been done. The execution and the achieved result have formed the basis of the proposed guidelines.

The result shows that smartphone cameras are of high quality and thereby could be used as a complement to advanced medical camera equipment. With the help of the proposed guidelines inexperienced persons could acquire sufficiently good medical photos, in order to be used as diagnostic material. This thesis provides a foundation for further research and implementation within the area, with the purpose of becoming an important part of the efficiency improvement within the telemedical health care.

• 38.
KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701). KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701). KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
Improved helmet design and test methods to reduce rotational induced brain injuries2003Conference paper (Refereed)

Accidental impacts to the human head are often a combination of translational and rotational accelerations. The most frequent severe brain injuries from accidents are diffuse axonal injury (DAI) and subdural hematoma that both are reported to arise from rotational violence to the head. Most helmet standards used today do only take the translational accelerations into account. It is therefore suggested that an oblique impact test that measures both translational and rotational accelerations should be a complement to the helmet standards used today. This study investigates the potential to reduce the risk for DAI by improving the helmet design by use of an oblique helmet impact test rig. The method used is a detailed finite element (FE) model of the human head. The FE model is used to measure the maximum principal strain in the brain which is suggested as a measurement for the risk to get DAI. The results clearly show the importance of testing a helmet in oblique impacts. Comparing a pure vertical impact with a 45 degree oblique impact with the same initial impact energy shows that the strain in the central parts of the brain is increased with a factor of 6. It is therefore suggested that a future helmet impact standard should include a rotational component so that the helmet is designed for both radial and tangential forces. Such a test method, an oblique impact test, was used to compare two different helmet designs. One helmet was manufactured with the shell glued to the liner and one helmet was designed with a low friction layer between the shell and the liner (MIPS). It was shown that the strain in the FE model of the human head was reduced be 27% comparing the MIPS helmet to the glued helmet design.

• 39.
KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701). KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701). KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
Reduced risk for DAI by use of a new safety helmet2003Conference paper (Refereed)

Accidental impacts to the human head are often a combination of translational and rotational accelerations. The most frequent severe brain injuries from accidents are diffuse axonal injury (DAI) and subdural hematoma that both are reported to arise from rotational violence to the head. Most helmet standards used today do only take the translational accelerations into account. It is therefore suggested that an oblique impact test that measures both translational and rotational accelerations should be a complement to the helmet standards used today. This study investigates the potential to reduce the risk for DAI by improving the helmet design by use of an oblique helmet impact test rig. The method used is a detailed finite element (FE) model of the human head. The FE model is used to measure the maximum principal strain in the brain which is suggested as a measurement for the risk to get DAI. The results clearly show the importance of testing a helmet in oblique impacts. Comparing a pure vertical impact with a 45 degree oblique impact with the same initial impact energy shows that the strain in the central parts of the brain is increased with a factor of 6. It is therefore suggested that a future helmet impact standard should include a rotational component so that the helmet is designed for both radial and tangential forces. Such a test method, an oblique impact test, was used to compare two different helmet designs. One helmet was manufactured with the shell glued to the liner and one helmet was designed with a low friction layer between the shell and the liner (MIPS). It was shown that the strain in the FE model of the human head was reduced be 27% comparing the MIPS helmet to the glued helmet design.

• 40.
KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
Chalmers tekniska högskola School of Mechanical Engineering. Institutionen för tillämpad mekanik. . Chalmers tekniska högskola School of Mechanical Engineering. Institutionen för tillämpad mekanik. . KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701). KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
Investigations of Conditions that Affect Neck Compression-Flexion Injuries Using Numerical Techniques2000In: Stapp Car Crash Journal, ISSN 1532-8546Article in journal (Refereed)
• 41.
KTH, School of Technology and Health (STH), Neuronic Engineering.
KTH, School of Technology and Health (STH), Neuronic Engineering.
Improved helmet design and test methods to reduce rotational induced brain injuries2009Conference paper (Other (popular science, discussion, etc.))
• 42.
KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
ETH Zurich, Switzerland.
Minimal set of markers for center of mass estimation in gravitational fall2009In: Proceedings of the ISB XXII Congress, 2009Conference paper (Refereed)
• 43.
KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS).
KTH, School of Technology and Health (STH), Medical sensors, signals and systems (MSSS). The Swedish School of Sport and Health Sciences. The Swedish School of Sport and Health Sciences. The Swedish Sport Confederation.
The antero-posterior movement of the sacrum as an indicator of the antero-posterior movement of center of mass in running2011In: Proceedings of ECSS 16th Congress, 2011Conference paper (Refereed)
• 44.
The Swedish School of Sport and Health Sciences.
Karolinska Institute. The Swedish School of Sport and Health Sciences.
The influence of declined support surface on the biomechanics of eccentric overload in squats2005In: Proceedings of the ISB XX Congress, 2005Conference paper (Refereed)
• 45.
Swedish School of Sports and Health Sciences.
Swedish University of Agricultural Sciences. Utrecht University. Uppsala University. Uppsala University.
Tracking the motion of hidden segments using kinematic constraints and Kalman filtering2008In: Journal of Biomechanical Engineering, ISSN 0148-0731, E-ISSN 1528-8951, Vol. 130Article in journal (Refereed)

Motion capture for biomechanical applications involves in almost all cases sensors or markers that are applied to the skin of the body segments of interest. This paper deals with the problem of estimating the movement of connected skeletal segments from 3D position data of markers attached to the skin. The use of kinematic constraints has been shown previously to reduce the error in estimated segment movement that are due to skin and muscles moving with respect to the underlying segment. A kinematic constraint reduces the number of degrees of freedom between two articulating segments. Moreover kinematic constraints can help reveal the movement of some segments when the 3D marker data otherwise are insufficient. Important cases include the human ankle complex and the phalangeal segments of the horse, where the movement of small segments is almost completely hidden from external observation by joint capsules and ligaments. This paper discusses the use of an extended Kalman filter for tracking a system of connected segments. The system is modeled using rigid segments connected by simplified joint models. The position and orientation of the mechanism are specified by a set of generalized coordinates corresponding to the mechanism's degrees of motion. The generalized coordinates together with their first time derivatives can be used as the state vector of a state space model governing the kinematics of the mechanism. The data collected are marker trajectories from skin-mounted markers, and the state vector is related to the position of the markers through a nonlinear function. The Jacobian of this function is derived The practical use of the method is demonstrated on a model of the distal part of the limb of the horse. Monte Carlo simulations of marker data for a two-segment system connected by a joint with three degrees of freedom indicate that the proposed method gives significant improvement over a method, which does not make use of the joint constraint, but the method requires that the model is a good approximation of the true mechanism. Applying the method to data on the movement of the four distal-most segments of the horse's limb shows good between trial consistency and small differences between measured marker positions and marker positions predicted by the model.

• 46.
Swedish School of Sports and Health Sciences.
Uppsala University. Uppsala University. Uppsala University.
Using an extended Kalman filter for rigid body pose estimation2005In: Journal of Biomechanical Engineering, ISSN 0148-0731, E-ISSN 1528-8951, Vol. 127, p. 475-483Article in journal (Refereed)

Rigid body pose is commonly represented as;he rigid body transformation from one (often reference) pose to another. This is usually computed for each frame of data without any assumptions or restrictions on the temporal change of the pose. The most common algorithm was proposed by Soderkvist and Wedin (1993, "Determining the Movements Of the Skeleton Using Well-configured Markers," J. Biomech., 26, pp. 1473-1477), and implies the assumption that measurement errors are isotropic and homogenous. This paper describes an alternative method based on a state space formulation and the application of an extended Kalman filter (EKF). State space models are formulated, which describe the kinematics of the rigid body. The state vector consists of six generalized coordinates (corresponding to the 6 degrees of freedom), and their first time derivatives. The state space models have linear dynamics, while the measurement function is a nonlinear relation between the state vector and the observations (marker positions). An analytical expression for the linearized measurement function is derived Tracking the rigid body motion using an EKF enables the use of a priori information on the measurement noise and type of motion to tune the filter. The EKF is time variant, which allows for a natural way of handling temporarily missing marker data. State updates are based on all the information available at each time step, even when data from fewer than three markers are available. Comparison with the method of Soderkvist and Wedin on simulated data showed a considerable improvement in accuracy with the proposed EKF method when marker data was temporarily missing. The proposed method offers an improvement in accuracy of rigid body pose estimation by incorporating knowledge of the characteristics of the movement and the measurement errors. Analytical expressions for the linearized system equations are provided, which eliminate the need for approximate discrete differentiation and which facilitate a fast implementation.

• 47.
KTH.
KTH, School of Electrical Engineering and Computer Science (EECS), Robotics, perception and learning, RPL.
Simultaneous measurement imputation and outcome prediction for achilles tendon rupture rehabilitation2018In: CEUR Workshop Proceedings, CEUR-WS , 2018, Vol. 2142, p. 82-86Conference paper (Refereed)

Achilles Tendon Rupture (ATR) is one of the typical soft tissue injuries. Accurately predicting the rehabilitation outcome of ATR using noisy measurements with missing entries is crucial for treatment decision support. In this work, we design a probabilistic model that simultaneously predicts the missing measurements and the rehabilitation outcome in an end-to-end manner. We evaluate our model and compare it with multiple baselines including multi-stage methods using an ATR clinical cohort. Experimental results demonstrate the superiority of our model for ATR rehabilitation outcome prediction.

• 48.
KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
KTH, School of Technology and Health (STH), Neuronic Engineering (Closed 20130701).
An automatic method to generate a patient specific finite element head model2006In: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 39, no 1, p. S428-Article in journal (Refereed)
• 49.
KTH, School of Technology and Health (STH), Neuronic Engineering.
KTH, School of Technology and Health (STH), Neuronic Engineering.
Investigation of the Dynamic Response Contribution of Vasculature in a 3D Finite Element Head Model2006Conference paper (Other academic)
• 50.
KTH, School of Technology and Health (STH), Neuronic Engineering.
KTH, School of Technology and Health (STH), Neuronic Engineering.
Investigation of the Dynamic Response Contribution of Vasculature in a 3D Finite Element Head Model2006Conference paper (Refereed)
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