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  • 1.
    Abouzayed, Ayman
    et al.
    Uppsala Univ, Dept Med Chem, S-75183 Uppsala, Sweden..
    Borin, Jesper
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Lundmark, Fanny
    Uppsala Univ, Dept Med Chem, S-75183 Uppsala, Sweden..
    Rybina, Anastasiya
    Russian Acad Sci, Canc Res Inst, Tomsk Natl Res Med Ctr, Dept Nucl Med, Tomsk 634009, Russia.;Tomsk Polytech Univ, Res Sch Chem & Appl Biomed Sci, Res Ctr Oncotheranost, Tomsk 634050, Russia..
    Hober, Sophia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science.
    Zelchan, Roman
    Russian Acad Sci, Canc Res Inst, Tomsk Natl Res Med Ctr, Dept Nucl Med, Tomsk 634009, Russia.;Tomsk Polytech Univ, Res Sch Chem & Appl Biomed Sci, Res Ctr Oncotheranost, Tomsk 634050, Russia..
    Tolmachev, Vladimir
    Uppsala Univ, Dept Immunol Genet & Pathol, S-75237 Uppsala, Sweden..
    Chernov, Vladimir
    Russian Acad Sci, Canc Res Inst, Tomsk Natl Res Med Ctr, Dept Nucl Med, Tomsk 634009, Russia..
    Orlova, Anna
    Uppsala Univ, Dept Med Chem, S-75183 Uppsala, Sweden.;Uppsala Univ, Sci Life Lab, S-75237 Uppsala, Sweden..
    The GRPR Antagonist [Tc-99m]Tc-maSSS-PEG(2)-RM26 towards Phase I Clinical Trial: Kit Preparation, Characterization and Toxicity2023In: Diagnostics, ISSN 2075-4418, Vol. 13, no 9, p. 1611-, article id 1611Article in journal (Refereed)
    Abstract [en]

    Gastrin-releasing peptide receptors (GRPRs) are overexpressed in the majority of primary prostate tumors and in prostatic lymph node and bone metastases. Several GRPR antagonists were developed for SPECT and PET imaging of prostate cancer. We previously reported a preclinical evaluation of the GRPR antagonist [Tc-99m]Tc-maSSS-PEG2-RM26 (based on [D-Phe(6), Sta(13), Leu(14)-NH2]BBN(6-14)) which bound to GRPR with high affinity and had a favorable biodistribution profile in tumor-bearing animal models. In this study, we aimed to prepare and test kits for prospective use in an early-phase clinical study. The kits were prepared to allow for a one-pot single-step radiolabeling with technetium-99m pertechnetate. The kit vials were tested for sterility and labeling efficacy. The radiolabeled by using the kit GRPR antagonist was evaluated in vitro for binding specificity to GRPR on PC-3 cells (GRPR-positive). In vivo, the toxicity of the kit constituents was evaluated in rats. The labeling efficacy of the kits stored at 4 degrees C was monitored for 18 months. The biological properties of [Tc-99m]Tc-maSSS-PEG2-RM26, which were obtained after this period, were examined both in vitro and in vivo. The one-pot (gluconic acid, ethylenediaminetetraacetic acid, stannous chloride, and maSSS-PEG(2)-RM26) single-step radiolabeling with technetium-99m was successful with high radiochemical yields (>97%) and high molar activities (16-24 MBq/nmol). The radiolabeled peptide maintained its binding properties to GRPR. The kit constituents were sterile and non-toxic when tested in living subjects. In conclusion, the prepared kit is considered safe in animal models and can be further evaluated for use in clinics.

  • 2. Abrahamsson, S.
    et al.
    Blom, Hans
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Agostinho, A.
    Jans, Daniel
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Jost, A.
    Müller, M.
    Nilsson, Linnea
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Bernhem, K.
    Lambert, T. J.
    Heintzmann, R.
    Brismar, Hjalmar
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Multifocus structured illumination microscopy for fast volumetric super-resolution imaging2017In: Biomedical Optics Express, E-ISSN 2156-7085, Vol. 8, no 9, p. 4135-4140, article id #294866Article in journal (Refereed)
    Abstract [en]

    We here report for the first time the synergistic implementation of structured illumination microscopy (SIM) and multifocus microscopy (MFM). This imaging modality is designed to alleviate the problem of insufficient volumetric acquisition speed in superresolution biological imaging. SIM is a wide-field super-resolution technique that allows imaging with visible light beyond the classical diffraction limit. Employing multifocus diffractive optics we obtain simultaneous wide-field 3D imaging capability in the SIM acquisition sequence, improving volumetric acquisition speed by an order of magnitude. Imaging performance is demonstrated on biological specimens.

  • 3.
    Abtahi, Farhad
    et al.
    KTH-School of Technology and Health.
    Ji, Guangchao
    KTH-School of Technology and Health.
    Lu, Ke
    KTH-School of Technology and Health.
    Rödby, Kristian
    University of Borås, Faculty of Textiles, Engineering and Business.
    Björlin, Anders
    Kiwok AB.
    Östlund, Anders
    Kiwok AB.
    Seoane, Fernando
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    Lindecrantz, Kaj
    KTH-School of Technology and Health.
    Textile-Electronic Integration in Wearable Measurement Garments for Pervasive Healthcare Monitoring2015Conference paper (Other academic)
  • 4.
    Abtahi, Farhad
    et al.
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Ji, Guangchao
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Lu, Ke
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Rödby, Kristian
    Högskolan i Borås, Akademin för textil, teknik och ekonomi.
    Björlin, Anders
    Kiwok AB.
    Östlund, Anders
    Kiwok AB.
    Seoane, Fernando
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems. Högskolan i Borås, Akademin för vård, arbetsliv och välfärd.
    Lindecrantz, Kaj
    KTH, School of Technology and Health (STH), Medical Engineering, Medical sensors, signals and systems.
    Textile-Electronic Integration in Wearable Measurement Garments for Pervasive Healthcare Monitoring2015Conference paper (Other academic)
  • 5.
    Abtahi, Farhad
    et al.
    KTH-School of Technology and Health.
    Ji, Guangchao
    KTH-School of Technology and Health.
    Lu, Ke
    KTH-School of Technology and Health.
    Rödby, Kristian
    University of Borås, Faculty of Textiles, Engineering and Business.
    Seoane, Fernando
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    A knitted garment using intarsia technique for Heart Rate Variability biofeedback: Evaluation of initial prototype2015In: Proceedings of the 2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015, p. 3121-3124Conference paper (Refereed)
  • 6. Abtahi, Farhad
    et al.
    Snäll, Jonathan
    Aslamy, Benjamin
    Abtahi, Shirin
    Seoane, Fernando
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    Lindecrantz, Kaj
    University of Borås, Faculty of Caring Science, Work Life and Social Welfare. KTH-School of Technology and Health.
    Biosignal PI, an Affordable Open-Source ECG and Respiration Measurement System2015In: Sensors, E-ISSN 1424-8220, Vol. 15, no 1, p. 93-109Article in journal (Refereed)
    Abstract [en]

    Bioimedical pilot projects e.g., telemedicine, homecare, animal and human trials usually involve several physiological measurements. Technical development of these projects is time consuming and in particular costly. A versatile but affordable biosignal measurement platform can help to reduce time and risk while keeping the focus on the important goal and making an efficient use of resources. In this work, an affordable and open source platform for development of physiological signals is proposed. As a first step an 8–12 leads electrocardiogram (ECG) and respiration monitoring system is developed. Chips based on iCoupler technology have been used to achieve electrical isolation as required by IEC 60601 for patient safety. The result shows the potential of this platform as a base for prototyping compact, affordable, and medically safe measurement systems. Further work involves both hardware and software development to develop modules. These modules may require development of front-ends for other biosignals or just collect data wirelessly from different devices e.g., blood pressure, weight, bioimpedance spectrum, blood glucose, e.g., through Bluetooth. All design and development documents, files and source codes will be available for non-commercial use through project website, BiosignalPI.org.

  • 7. Agogo, George O.
    et al.
    van der Voet, Hilko
    van 't Veer, Pieter
    Ferrari, Pietro
    Muller, David C.
    Sanchez-Cantalejo, Emilio
    Bamia, Christina
    Braaten, Tonje
    Knuppel, Sven
    Johansson, Ingegerd
    Umeå University, Faculty of Medicine, Department of Odontology.
    van Eeuwijk, Fred A.
    Boshuizen, Hendriek C.
    A method for sensitivity analysis to assess the effects of measurement error in multiple exposure variables using external validation data2016In: BMC Medical Research Methodology, E-ISSN 1471-2288, Vol. 16, article id 139Article in journal (Refereed)
    Abstract [en]

    Background: Measurement error in self-reported dietary intakes is known to bias the association between dietary intake and a health outcome of interest such as risk of a disease. The association can be distorted further by mismeasured confounders, leading to invalid results and conclusions. It is, however, difficult to adjust for the bias in the association when there is no internal validation data. Methods: We proposed a method to adjust for the bias in the diet-disease association (hereafter, association), due to measurement error in dietary intake and a mismeasured confounder, when there is no internal validation data. The method combines prior information on the validity of the self-report instrument with the observed data to adjust for the bias in the association. We compared the proposed method with the method that ignores the confounder effect, and with the method that ignores measurement errors completely. We assessed the sensitivity of the estimates to various magnitudes of measurement error, error correlations and uncertainty in the literature-reported validation data. We applied the methods to fruits and vegetables (FV) intakes, cigarette smoking (confounder) and all-cause mortality data from the European Prospective Investigation into Cancer and Nutrition study. Results: Using the proposed method resulted in about four times increase in the strength of association between FV intake and mortality. For weakly correlated errors, measurement error in the confounder minimally affected the hazard ratio estimate for FV intake. The effect was more pronounced for strong error correlations. Conclusions: The proposed method permits sensitivity analysis on measurement error structures and accounts for uncertainties in the reported validity coefficients. The method is useful in assessing the direction and quantifying the magnitude of bias in the association due to measurement errors in the confounders.

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  • 8.
    Ahlander, Britt-Marie
    Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
    Magnetic Resonance Imaging of the Heart: Image quality, measurement accuracy and patient experience2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Non-invasive diagnostic imaging of atherosclerotic coronary artery disease (CAD) is frequently carried out with cardiovascular magnetic resonance imaging (CMR) or myocardial perfusion single photon emission computed tomography (MPS). CMR is the gold standard for the evaluation of scar after myocardial infarction and MPS the clinical gold standard for ischemia. Magnetic Resonance Imaging (MRI) is at times difficult for patients and may induce anxiety while patient experience of MPS is largely unknown.

    Aims: To evaluate image quality in CMR with respect to the sequences employed, the influence of atrial fibrillation, myocardial perfusion and the impact of patient information. Further, to study patient experience in relation to MRI with the goal of improving the care of these patients.

    Method: Four study designs have been used. In paper I, experimental cross-over, paper (II) experimental controlled clinical trial, paper (III) psychometric crosssectional study and paper (IV) prospective intervention study. A total of 475 patients ≥ 18 years with primarily cardiac problems (I-IV) except for those referred for MRI of the spine (III) were included in the four studies.

    Result: In patients (n=20) with atrial fibrillation, a single shot steady state free precession (SS-SSFP) sequence showed significantly better image quality than the standard segmented inversion recovery fast gradient echo (IR-FGRE) sequence (I). In first-pass perfusion imaging the gradient echo-echo planar imaging sequence (GREEPI) (n=30) had lower signal-to-noise and contrast–to-noise ratios than the steady state free precession sequence (SSFP) (n=30) but displayed a higher correlation with the MPS results, evaluated both qualitatively and quantitatively (II). The MRIAnxiety Questionnaire (MRI-AQ) was validated on patients, referred for MRI of either the spine (n=193) or the heart (n=54). The final instrument had 15 items divided in two factors regarding Anxiety and Relaxation. The instrument was found to have satisfactory psychometric properties (III). Patients who prior CMR viewed an information video scored significantly (lower) better in the factor Relaxation, than those who received standard information. Patients who underwent MPS scored lower on both factors, Anxiety and Relaxation. The extra video information had no effect on CMR image quality (IV).

    Conclusion: Single shot imaging in atrial fibrillation produced images with less artefact than a segmented sequence. In first-pass perfusion imaging, the sequence GRE-EPI was superior to SSFP. A questionnaire depicting anxiety during MRI showed that video information prior to imaging helped patients relax but did not result in an improvement in image quality.

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    Magnetic Resonance Imaging of the Heart: Image quality, measurement accuracy and patient experience
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  • 9.
    Ahlander, Britt-Marie
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Magnetic Resonance Imaging of the Heart: Image quality, measurement accuracy and patient experience2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Background: Non-invasive diagnostic imaging of atherosclerotic coronary artery disease (CAD) is frequently carried out with cardiovascular magnetic resonance imaging (CMR) or myocardial perfusion single photon emission computed tomography (MPS). CMR is the gold standard for the evaluation of scar after myocardial infarction and MPS the clinical gold standard for ischemia. Magnetic Resonance Imaging (MRI) is at times difficult for patients and may induce anxiety while patient experience of MPS is largely unknown.

    Aims: To evaluate image quality in CMR with respect to the sequences employed, the influence of atrial fibrillation, myocardial perfusion and the impact of patient information. Further, to study patient experience in relation to MRI with the goal of improving the care of these patients.

    Method: Four study designs have been used. In paper I, experimental cross-over, paper (II) experimental controlled clinical trial, paper (III) psychometric crosssectional study and paper (IV) prospective intervention study. A total of 475 patients ≥ 18 years with primarily cardiac problems (I-IV) except for those referred for MRI of the spine (III) were included in the four studies.

    Result: In patients (n=20) with atrial fibrillation, a single shot steady state free precession (SS-SSFP) sequence showed significantly better image quality than the standard segmented inversion recovery fast gradient echo (IR-FGRE) sequence (I). In first-pass perfusion imaging the gradient echo-echo planar imaging sequence (GREEPI) (n=30) had lower signal-to-noise and contrast–to-noise ratios than the steady state free precession sequence (SSFP) (n=30) but displayed a higher correlation with the MPS results, evaluated both qualitatively and quantitatively (II). The MRIAnxiety Questionnaire (MRI-AQ) was validated on patients, referred for MRI of either the spine (n=193) or the heart (n=54). The final instrument had 15 items divided in two factors regarding Anxiety and Relaxation. The instrument was found to have satisfactory psychometric properties (III). Patients who prior CMR viewed an information video scored significantly (lower) better in the factor Relaxation, than those who received standard information. Patients who underwent MPS scored lower on both factors, Anxiety and Relaxation. The extra video information had no effect on CMR image quality (IV).

    Conclusion: Single shot imaging in atrial fibrillation produced images with less artefact than a segmented sequence. In first-pass perfusion imaging, the sequence GRE-EPI was superior to SSFP. A questionnaire depicting anxiety during MRI showed that video information prior to imaging helped patients relax but did not result in an improvement in image quality.

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    Magnetic Resonance Imaging of the Heart: Image quality, measurement accuracy and patient experience
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  • 10.
    Ahlander, Britt-Marie
    et al.
    Department of Radiology, Ryhov County Hospital, Jönköping.
    Maret, Eva
    Department of Radiology, Ryhov County Hospital, Jönköping / Department of Clinical Physiology, Karolinska University Hospital, Stockholm.
    Brudin, Lars
    Department of Clinical Physiology, Kalmar County Hospital, Kalmar.
    Starck, Sven-Åke
    Department of Natural Science and Biomedicine, School of Health Sciences, Jönköping University / Department of Oncology, Hospital Physics, Ryhov County Hospital, Jönköping.
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    An echo-planar imaging sequence is superior to a steady-state free precession sequence for visual as well as quantitative assessment of cardiac magnetic resonance stress perfusion2017In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 37, no 1, p. 52-61Article in journal (Refereed)
    Abstract [en]

    Background To assess myocardial perfusion, steady-state free precession cardiac magnetic resonance (SSFP, CMR) was compared with gradient-echo–echo-planar imaging (GRE-EPI) using myocardial perfusion scintigraphy (MPS) as reference. Methods Cardiac magnetic resonance perfusion was recorded in 30 patients with SSFP and in another 30 patients with GRE-EPI. Timing and extent of inflow delay to the myocardium was visually assessed. Signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were calculated. Myocardial scar was visualized with a phase-sensitive inversion recovery sequence (PSIR). All scar positive segments were considered pathologic. In MPS, stress and rest images were used as in clinical reporting. The CMR contrast wash-in slope was calculated and compared with the stress score from the MPS examination. CMR scar, CMR perfusion and MPS were assessed separately by one expert for each method who was blinded to other aspects of the study. Results Visual assessment of CMR had a sensitivity for the detection of an abnormal MPS at 78% (SSFP) versus 91% (GRE-EPI) and a specificity of 58% (SSFP) versus 84% (GRE-EPI). Kappa statistics for SSFP and MPS was 0·29, for GRE-EPI and MPS 0·72. The ANOVA of CMR perfusion slopes for all segments versus MPS score (four levels based on MPS) had correlation r = 0·64 (SSFP) and r = 0·96 (GRE-EPI). SNR was for normal segments 35·63 ± 11·80 (SSFP) and 17·98 ± 8·31 (GRE-EPI), while CNR was 28·79 ± 10·43 (SSFP) and 13·06 ± 7·61 (GRE-EPI). Conclusion GRE-EPI displayed higher agreement with the MPS results than SSFP despite significantly lower signal intensity, SNR and CNR.

  • 11.
    Ahlström, Christer
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Health Sciences.
    Nonlinear phonocardiographic Signal Processing2008Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The aim of this thesis work has been to develop signal analysis methods for a computerized cardiac auscultation system, the intelligent stethoscope. In particular, the work focuses on classification and interpretation of features derived from the phonocardiographic (PCG) signal by using advanced signal processing techniques.

    The PCG signal is traditionally analyzed and characterized by morphological properties in the time domain, by spectral properties in the frequency domain or by nonstationary properties in a joint time-frequency domain. The main contribution of this thesis has been to introduce nonlinear analysis techniques based on dynamical systems theory to extract more information from the PCG signal. Especially, Takens' delay embedding theorem has been used to reconstruct the underlying system's state space based on the measured PCG signal. This processing step provides a geometrical interpretation of the dynamics of the signal, whose structure can be utilized for both system characterization and classification as well as for signal processing tasks such as detection and prediction. In this thesis, the PCG signal's structure in state space has been exploited in several applications. Change detection based on recurrence time statistics was used in combination with nonlinear prediction to remove obscuring heart sounds from lung sound recordings in healthy test subjects. Sample entropy and mutual information were used to assess the severity of aortic stenosis (AS) as well as mitral insufficiency (MI) in dogs. A large number of, partly nonlinear, features was extracted and used for distinguishing innocent murmurs from murmurs caused by AS or MI in patients with probable valve disease. Finally, novel work related to very accurate localization of the first heart sound by means of ECG-gated ensemble averaging was conducted. In general, the presented nonlinear processing techniques have shown considerably improved results in comparison with other PCG based techniques.

    In modern health care, auscultation has found its main role in primary or in home health care, when deciding if special care and more extensive examinations are required. Making a decision based on auscultation is however difficult, why a simple tool able to screen and assess murmurs would be both time- and cost-saving while relieving many patients from needless anxiety. In the emerging field of telemedicine and home care, an intelligent stethoscope with decision support abilities would be of great value.

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    FULLTEXT01
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    COVER01
  • 12.
    Ahlström, Christer
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Hult, Peter
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, Faculty of Arts and Sciences.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Detection of the 3(rd) heart sound using recurrence time statistics2006In: 2006 IEEE International Conference on Acoustics, Speech and Signal Processing, Vols 1-13, 2006, Vol. 1-13, p. 2288-2291Conference paper (Refereed)
    Abstract [en]

    The 3(rd) heart sound (S3) is normally heard during auscultation of younger individuals, but it is also common in many patients with heart failure. Compared to the 1(st) and 2(nd) heart sounds, S3 has low amplitude and low frequency content, making it hard to detect (both manually for the physician and automatically by a detection algorithm). We present an algorithm based on a recurrence time statistic which is sensitive to changes in a reconstructed state space, particularly for detection of transitions with very low energy. Heart sound signals from ten children were used in this study. Most S3 occurrences were detected (98%), but the amount of false extra detections was rather high (7% of the heart cycles). In conclusion, the method seems capable of detecting S3 with high accuracy and robustness.

  • 13.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Dukic, Tania
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Patten, Christopher
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Measuring driver impairments: Sleepiness, distraction, and workload2012In: IEEE Pulse, ISSN 2154-2287, Vol. 3, no 2, p. 22-30Article in journal (Refereed)
    Abstract [en]

    Snow was falling heavily when Sarah was driving on a slippery road to her cousin’s country cottage. It was dark outside, and the visibility was poor. She had planned to arrive before sunset, but the rental service had made a mistake, and it took hours before she got her rental car at the airport. It was past midnight now, and after a long day of traveling, Sarah was starting to get sleepy.

    Fortunately, there were only 15 km to go, but her eyelids were starting to feel heavy. To stay awake, she put her favorite CD on, turned up the volume, and started to sing along. This seemed to help a little -good- only 10 km to go. This was when Sarah’s phone started ringing, and she awkwardly tried to find the mute button for the car stereo while answering the phone. As she looked up again, she barely caught a glimpse of the red brake lights of the car in front of her as she smashed into it.

  • 14.
    Ahlström, Christer
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Nyström, Marcus
    Lunds Universitet.
    Holmqvist, Kenneth
    Lunds Universitet.
    Fors, Carina
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Sandberg, David
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Anund, Anna
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kecklund, Göran
    Stockholms Universitet.
    Ņkerstedt, Torbjörn
    Stockholms Universitet.
    Fit-for-duty test for estimation of drivers’ sleepiness level: Eye movements improve the sleep/wake predictor2013In: Transportation Research Part C: Emerging Technologies, ISSN 0968-090X, E-ISSN 1879-2359, Vol. 26, p. 20-32Article in journal (Refereed)
    Abstract [en]

    Driver sleepiness contributes to a considerable proportion of road accidents, and a fit-for-duty test able to measure a driver’s sleepiness level might improve traffic safety. The aim of this study was to develop a fit-for-duty test based on eye movement measurements and on the sleep/wake predictor model (SWP, which predicts the sleepiness level) and evaluate the ability to predict severe sleepiness during real road driving. Twenty-four drivers participated in an experimental study which took place partly in the laboratory, where the fit-for-duty data were acquired, and partly on the road, where the drivers sleepiness was assessed. A series of four measurements were conducted over a 24-h period during different stages of sleepiness. Two separate analyses were performed; a variance analysis and a feature selection followed by classification analysis. In the first analysis it was found that the SWP and several eye movement features involving anti-saccades, pro-saccades, smooth pursuit, pupillometry and fixation stability varied significantly with different stages of sleep deprivation. In the second analysis, a feature set was determined based on floating forward selection. The correlation coefficient between a linear combination of the acquired features and subjective sleepiness (Karolinska sleepiness scale, KSS) was found to be R=. 0.73 and the correct classification rate of drivers who reached high levels of sleepiness (KSS ≥ 8) in the subsequent driving session was 82.4% (sensitivity = 80.0%, specificity = 84.2% and AUC = 0.86). Future improvements of a fit-for-duty test should focus on how to account for individual differences and situational/contextual factors in the test, and whether it is possible to maintain high sensitive/specificity with a shorter test that can be used in a real-life environment, e.g. on professional drivers. © 2012 Elsevier Ltd.

  • 15.
    Ahmed, Masud Omar
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Teststation för industriella UV-celler2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    GE Healthcare Bio-Sciences AB in Umeå produce a variety of chromatography systems. One of the main components in chromatography is the UV module, which measure the light absorption of different wavelengths in the liquid being pumped through a cell. Currently at the Umeå site two types of UV-cells are produced; lab cells and industrial cells. The current test station for the industrial UV-cells is outdated, in disrepair and no longer supported.  GE has developed a test station for the lab cells that evaluates UV and flow properties, the data is stored in GE’s own production database, Prodas.

    The aim of this work is to design a test station for industrial UV-cells to improve the quality of the cells. The primary goal is a test station that can measure pressure, flow and absorption. The secondary goal is to discover and if possible, implement solutions that will streamline and automate the test station.

    A prototype of a test station for industrial UV-cells based on that for lab cells has been developed. The solution consists of an adapter that links the light path from the monitor through the UV-cell to the detector. The test station can measure pressure, flow and absorption but can only perform absorption and leakage tests.  Automation and efficiency have been accomplished in the form of scripts used to conduct absorption and leakage tests. The test station requires further development before it can be used in the production line.

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  • 16.
    Ainegren, Mats
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Management and Mechanical Engineering.
    Jensen, Kurt
    Syddansk Universitet, Odense, Danmark.
    Rosdahl, Hans
    Swedish School of Sport and Health Sciences, GIH, Stockholm.
    Breathing resistance in automated metabolic systems is high in comparison with the Douglas Bag method and previous recommendations2018In: Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology, ISSN 1754-3371, Vol. 232, no 2, p. 122-130Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to investigate the resistance (RES) to breathing in metabolic systems used for the distribution and measurement of pulmonary gas exchange. A mechanical lung simulator was used to standardize selected air flow rates ( , L/s). The delta pressure (∆p, Pa) between ambient air and the air inside the equipment was measured in the breathing valve’s mouthpiece adapter for four metabolic systems and four types of breathing valves. RES for the inspiratory and expiratory sides was calculated as RES = ∆p / , Pa/L/s. The results for RES showed significant (p < 0.05) between-group variance among the tested metabolic systems, as well as the breathing valves and between most of the completed . The lowest RES among the metabolic systems was found for a Douglas Bag system, with approximately half of the RES compared to the automated metabolic systems. The automated systems were found to have higher RES already at low  in comparison to previous recommendations. For the hardware components, the highest RES was found for the breathing valves while the lowest RES was found for the hoses. Conclusion: The results showed that RES in metabolic systems can be minimized through conscious choices of system design and hardware components. 

  • 17.
    Ajan, Aida
    et al.
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Maxillofacial Unit.
    Roberg, Karin
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Otorhinolaryngology.
    Fredriksson, Ingemar
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Abtahi, Jahan
    Linköping University, Department of Biomedical and Clinical Sciences, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Maxillofacial Unit.
    Reproducibility of Laser Doppler Flowmetry in gingival microcirculation. A study on six different protocols2024In: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 153, article id 104666Article in journal (Refereed)
    Abstract [en]

    Objectives: Laser Doppler Flowmetry (LDF) is a non-invasive technique for the assessment of tissue blood flow, but increased reproducibility would facilitate longitudinal studies. The aim of the study was to assess the interday reproducibility of Laser Doppler Flowmetry (LDF) at rest, at elevated local temperatures, and with the use of the vasodilator Methyl Nicotinate (MN) in six interconnected protocols for the measurement of the blood supply to the microvascular bed of the gingiva. Methods: Ten healthy volunteers were included. Interweek LDF measurements with custom-made acrylic splints were performed. Six protocols were applied in separate regions of interest (ROI): 1; basal LDF, 2; LDF with thermoprobe 42 degrees C, 3; LDF with thermoprobe 45 degrees C, 4; LDF with thermoprobe 42 degrees C and MN, 5; LDF with thermoprobe 45 C and MN and 6; LDF with MN. Results: Intra-individual reproducibility was assessed by the within -subject coefficient of variation (wCV) and the intraclass correlation coefficient (ICC). Basal LDF measurements demonstrated high reproducibility with wCV 11.1 in 2 min and 10.3 in 5 min. ICC was 0.9 and 0.92. wCV after heat and MN was 4.9-10.3 and ICC 0.82-0.93. The topically applied MN yielded increased blood flow. Conclusion: This is the first study evaluating the reproducibility of basal LDF compared to single or multiple vasodilatory stimuli in gingiva. Multiple collector fibers probe and stabilizing acrylic splints are recommended. Vasodilatory stimulation showed a tendency toward higher reproducibility. Furthermore, MN yields vasodilation in gingiva.

  • 18.
    Al Kouatli, Hakim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Achmawi, Mohamed
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Nanotechnology and Functional Materials.
    Utvärdering av en befintlig plattform för neurofeedback med hjälp av open-source EEG2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Neurofeedback is a type of biofeedback in which subjects learn to use the activity of their own electrical brain waves to respond to a visual or auditory feedback from the activity of the brain. This is done by connecting electrodes to the body to get the brain's electrical activity in the form of encephalogram signals (EEG) which are then calculated and converted into useful feedback.The purpose of this work was to evaluate a neurofeedback platform via an OpenBCI open-source EEG technology that could lead to more accessible neurofeedback for society.This study was conducted with different methods where the focus was on testing and data analysis. The study has included a summary of theory used in neurofeedback, a comprehensive pilot study on an 8-channel open-source EEG neurofeedback platform and some of the ethical aspects behind the technology used and neurofeedback in Sweden. During the work, two different experts were interviewed: Gunilla Radu, founder and owner of Nordic Center of Neurofeedback AB and Jan Rutkowski, who is an engineer in medical engineering at the Uppsala Hospital.The tests with 8-channel EEG with an OpenBCI hardware and software show results from three subjects. The answers from a follow-up survey that subjects were allowed to answer are presented in the report. This was used as an evaluation of the tests performed. The aim of the tests was to give Biohackeri an opportunity to see the potential for a neurofeedback platform and to create a basis for further development of such a platform. The result indicates that a measurement of the brain activity at rest with the technology from OpenBCI shows a higher concentration level in the human body with open eyes compared to closed eyes. In addition, a higher level of relaxation is noticed when resting with eyes closed compared to eyes open. Answers from the survey show that what is important to the test subjects is, among other things, the convenience while testing the technology. In terms of requirements and rules that Neurofeedback therapists must meet, it turned out that in Sweden therapists do not need to have a specific background or education. There are ethical perspectives that Neurofeedback therapists may consider in implementing Neurofeedback Therapy.The conclusion of this project is that the tested 8-channel EEG equipment gives a result that agrees with the presented theory. Thus, a Neurofeedback platform could be built on the commercially available open-source technology, such as the technology from OpenBCI.

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    Utvärdering av en befintlig plattform för neurofeedback med hjälp av open-source EEG
  • 19.
    Alander, Jarmo
    et al.
    Department of Electrical Engineering and Automation, University of Vaasa.
    Autere, Antti
    Department of Electrical Engineering and Automation, University of Vaasa.
    Kanniainen, Olli
    Department of Electrical Engineering and Automation, University of Vaasa.
    Koljonen, Janne
    Department of Electrical Engineering and Automation, University of Vaasa.
    Nordling, Torbjörn E M
    Department of Electrical Engineering and Automation, University of Vaasa.
    Välisuo, Petri
    Department of Electrical Engineering and Automation, University of Vaasa.
    Near infrared wavelength relevance detection of ultraviolet radiation-induced erythema2008In: Journal of Near Infrared Spectroscopy, ISSN 0967-0335, E-ISSN 1751-6552, Vol. 16, no 3, p. 233-241Article in journal (Refereed)
    Abstract [en]

    The acute effects of sun-bathing on the near-infrared absorption spectra of human skin were studied by exposing the shoulders of a male test subject to bright Finnish high summer mid-day sun. The spectra were measured before, immediately after and for several days after exposure. Four different spectral. processing and classification methods were applied to the data set to identify differences caused by exposure to the sun. The spectrophotometer and measuring procedure were found to cause some systematic errors, calling for further development, even though they could, to a large extent, be compensated for computationally. Spectral regions indicating ultraviolet radiation-induced erythema were Located and the degree of erythema could be predicted correctly but the signal is weak. This paper discusses promising wavelength selection methods to study the dermal effects of exposure to the sun, as well as difficulties and remedies of near infrared spectroscopic measurements of the skin.

  • 20.
    Almeida, Nuno
    et al.
    Katholieke University of Leuven, Belgium; GE Vingmed Ultrasound AS, Norway.
    Papachristidis, Alexandros
    Kings Coll Hospital London, England.
    Pearson, Peter
    Kings Coll Hospital London, England.
    Imre Sarvari, Sebastian
    University of Oslo, Norway.
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Edvardsen, Thor
    University of Oslo, Norway.
    Monaghan, Mark
    Kings Coll Hospital London, England.
    Gerard, Olivier
    GE Vingmed Ultrasound AS, Norway.
    Samset, Eigil
    GE Vingmed Ultrasound AS, Norway; University of Oslo, Norway.
    Dhooge, Jan
    Katholieke University of Leuven, Belgium.
    Left atrial volumetric assessment using a novel automated framework for 3D echocardiography: a multi-centre analysis2017In: European Heart Journal Cardiovascular Imaging, ISSN 2047-2404, E-ISSN 2047-2412, Vol. 18, no 9, p. 1008-1015Article in journal (Refereed)
    Abstract [en]

    Aims This study aims at validating a software tool for automated segmentation and quantification of the left atrium (LA) from 3D echocardiography. Methods and results The LA segmentation tool uses a dual-chamber model of the left side of the heart to automatically detect and track the atrio-ventricular plane and the LA endocardium in transthoracic 3D echocardiography. The tool was tested in a dataset of 121 ultrasound images from patients with several cardiovascular pathologies (in a multi-centre setting), and the resulting volumes were compared with those assessed manually by experts in a blinded analysis using conventional contouring. Bland-Altman analysis showed good agreement between the automated method and the manual references, with differences (mean +/- 1.96 SD) of 0.5 +/- 5.7 mL for LA minimum volume and -1.6 +/- 9.7 mL for LA maximum volume (comparable to the inter-observer variability of manual tracings). The automated tool required no user interaction in 93% of the recordings, while 4% required a single click and only 2% required contour adjustments, reducing considerably the amount of time and effort required for LA volumetric analysis. Conclusion The automated tool was validated in a multi-centre setting, providing quantification of the LA volume over the cardiac cycle with minimal user interaction. The results of the automated analysis were in agreement with those estimated manually by experts. This study shows that such approach has clinical utility for the assessment of the LA morphology and function, automating and facilitating the time-consuming task of analysing 3D echocardiographic recordings.

  • 21.
    Almqvist, Ulf
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Sjörs, Anna
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Validation of MobileMe: a psychophysiological recording system – from a motion sickness perspective2006Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    MobileMe is a recently developed system for monitoring and recording physiological variables. It is wireless, and can therefore be suitable for field research, for example when measuring motion sickness symptoms.

    The aim of this thesis was to conclude whether the MobileMe recording system was valid for research studies. A validation study, consisting of two parts and including 10 subjects, was performed. The first part was a laboratory study, where data from MobileMe and a reference equipment were compared. A field study was also performed, onboard a combat boat, to determine the equipment’s validity in uncontrolled environments. Furthermore, the field study included an investigation of motion sickness symptoms, and provided data for evaluation of motion sickness rating scales.

    Statistical results from the laboratory study, and results from evaluation of data from the field study, showed that MobileMe was valid in both controlled and uncontrolled environments.

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  • 22.
    Altgärde, Noomi
    Linköping University, Department of Physics, Chemistry and Biology.
    Local release of lithium from sol-gel coated orthopaedic screws: an in vitro and in vivo study2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

     

    In orthopaedic practice, fractures are usually stabilised with metal screws or rods. This is done in order to keep the fracture parts in place during the rather slow healing process. The healing time can potentially be reduced by local- or systemic treatment with different bone promoting drugs. In later years, lithium, otherwise used to treat bipolar disease, has shown promise to be such a drug.

     

    The aim of this master thesis was to find a way to coat metal bone screws with lithium and to characterise the coating. The coating was to be designed in such a way that it could release lithium to the surrounding bone tissue.

     

    Lithium chloride was incorporated into a titanate sol-gel and attached to silicon wafers and stainless steel screws by dip coating. Wafers were used for initial in vitro studies of how lithium changed coating characteristics. This was studied using ellipsometry, AFM and SEM. Lithium is most probably physisorbed and not incorporated into the network building up the sol-gel. Coating structure is changed as more lithium is incorporated. For large amounts of lithium, the nanoparticles normally formed when curing the sol-gel are inhibited. One effect of this is reduced bioactivity, seen as a reduced ability for calcium phosphate crystals to nucleate on the coating when immersed in simulated body fluid.

    Lithium release was investigated using AAS. Lithium is released from the coating, showing a burst effect. By changing the number of coating layers used, the release profile can be partly altered. The coating was also applied to screws, showing good attachment, and the lithium release profile was similar to the one seen from wafers.

    Finally, a screw model was used in rats to assess the effect of local lithium treatment from screws and systemic lithium treatment on fracture healing. In the model, a screw was inserted in tibia, mimicking a fracture. When the bone around the screw was healed, a pullout test was performed, giving information about the strength of the bone surrounding the screw. No significant difference could be found for either local- or systemic lithium treatment compared to control. However, when evaluating the strength of intact bone in a similar way, a positive effect of systemic lithium treatment could be seen. Therefore, it is still likely that lithium has a positive effect on bone and further studies are needed to fully evaluate its role in fracture healing.

     

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  • 23.
    Alyounes, Qsai
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Razan, Alkari
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering.
    Characterization of monkey fat tissues: To assist their viability for fat intra-body communication as an early step of non-human primate testing (NHP)2022Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Fat intra-body communication is a newly proven concept that is built on using human fat tissues as a communication channel for electromagnetic waves inside the body. This allows for two implanted external devices to connect through an intra-body closed-loop communication channel. This concept utilizes the fact that the fat tissues have low dielectric properties and are located between two tissue layers, skin and muscle, which have high dielectric permittivity and high loss tangent so that the signal propagates and confines with lower losses within the fat tissue. In this study, the eligibility of using monkey fat tissues as a communication channel for intra-body communication is being investigated. This comes as a first step in a long process of testing implementing medical devices, mainly prosthetic limbs, on non-human primates using fat-IBC at microwave frequencies. To be able to do that, an experimental characterization of ex-vivo monkey fat, skin, and muscle tissues to explore their dielectric properties compared to those of humans is being carried out. This study of the dielectric properties of monkey tissues is the first of its kind to be carried out on two samples of ex-vivo monkey tissues. Calf tissues have also been investigated in the study to get an insight on the potential differences between human and non-human body tissues in general before doing measurements on monkey tissues. For the measurements, an RF network analyzer and an open-ended coaxial probe method have been implemented. Phantoms that mimic the human tissues have been fabricated to be used as a reference point. The initial investigation demonstrates that calf fat tissues have much higher dielectric properties than human fat tissues. Monkey fat, muscle, and skin tissues showed many similarities to human tissues regarding their dielectric properties. This indicates that monkey tissues can be used for fat intra-body communication. Future numerical and analytical modeling of the monkey tissues needs to be conducted to confirm and strengthen this finding.

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  • 24.
    Ambarki, Khalid
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lindqvist, Tomas
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Wåhlin, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Petterson, E
    Warntjes, JBM
    Birgander, Richard
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Malm, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Eklund, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Evaluation of automatic measurement of the intracranial volume based on quantitative MR imaging2012In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 33, no 10, p. 1951-1956Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND PURPOSE: Brain size is commonly described in relation to ICV, whereby accurate assessment of this quantity is fundamental. Recently, an optimized MR sequence (QRAPMASTER) was developed for simultaneous quantification of T1, T2, and proton density. ICV can be measured automatically within minutes from QRAPMASTER outputs and a dedicated software, SyMRI. Automatic estimations of ICV were evaluated against the manual segmentation.

    MATERIALS AND METHODS: In 19 healthy subjects, manual segmentation of ICV was performed by 2 neuroradiologists (Obs1, Obs2) by using QBrain software and conventional T2-weighted images. The automatic segmentation from the QRAPMASTER output was performed by using SyMRI. Manual corrections of the automatic segmentation were performed (corrected-automatic) by Obs1 and Obs2, who were blinded from each other. Finally, the repeatability of the automatic method was evaluated in 6 additional healthy subjects, each having 6 repeated QRAPMASTER scans. The time required to measure ICV was recorded.

    RESULTS: No significant difference was found between reference and automatic (and corrected-automatic) ICV (P > .25). The mean difference between the reference and automatic measurement was -4.84 ± 19.57 mL (or 0.31 ± 1.35%). Mean differences between the reference and the corrected-automatic measurements were -0.47 ± 17.95 mL (-0.01 ± 1.24%) and -1.26 ± 17.68 mL (-0.06 ± 1.22%) for Obs1 and Obs2, respectively. The repeatability errors of the automatic and the corrected-automatic method were <1%. The automatic method required 1 minute 11 seconds (SD = 12 seconds) of processing. Adding manual corrections required another 1 minute 32 seconds (SD = 38 seconds).

    CONCLUSIONS: Automatic and corrected-automatic quantification of ICV showed good agreement with the reference method. SyMRI software provided a fast and reproducible measure of ICV.

  • 25. Ambrosi, D.
    et al.
    Ateshian, G. A.
    Arruda, E. M.
    Cowin, S. C.
    Dumais, J.
    Goriely, A.
    Holzapfel, Gerhard A.
    KTH, School of Engineering Sciences (SCI), Mechanics, Biomechanics.
    Humphrey, J. D.
    Kemkemer, R.
    Kuhl, E.
    Olberding, J. E.
    Taber, L. A.
    Garikipati, K.
    Perspectives on biological growth and remodeling2011In: Journal of the mechanics and physics of solids, ISSN 0022-5096, E-ISSN 1873-4782, Vol. 59, no 4, p. 863-883Article, review/survey (Refereed)
    Abstract [en]

    The continuum mechanical treatment of biological growth and remodeling has attracted considerable attention over the past fifteen years. Many aspects of these problems are now well-understood, yet there remain areas in need of significant development from the standpoint of experiments, theory, and computation. In this perspective paper we review the state of the field and highlight open questions, challenges, and avenues for further development.

  • 26. Anderson, C.
    et al.
    Andersson, T.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Changes in skin circulation after microdialysis probe insertion visualized by laser Doppler perfusion imaging1994In: Journal of Investigative Dermatology, ISSN 0022-202X, E-ISSN 1523-1747, Vol. 102, no 5, p. 807-811Article in journal (Refereed)
    Abstract [en]

    Microdialysis makes possible in vivo estimation of endogenous and exogenous substances in the dermal extracellular space. Insertion of the microdialysis probe and its subsequent presence in the skin may affect both the reactivity of the skin test site and the measurement of target substances. Laser Doppler flowmetry is a non-invasive method for estimating cutaneous blood flow. A further development of this technique, laser Doppler perfusion imaging, has been used to study the time course of the circulatory changes caused in the area of microdialysis probe insertion. Laser Doppler perfusion imaging was performed prior to, during, and after microdialysis probe insertion in the skin of the ventral forearm in three subjects. Probe insertion caused an increase in skin blood perfusion in the whole test area. About 15 min after probe insertion, the flare, which is presumed to be of chiefly axon reflex origin, began to subside and the circulatory response could be seen to center around the site of insertion and the tip of the probe. Skin perfusion levels had returned to near normal levels within 60 min. Local anesthesia of the point of guide insertion inhibited the flare, but did not affect circulatory reactivity in the skin nearby. Both microdialysis and laser Doppler perfusion imaging seem to be promising new methods in dermatologic research.

  • 27. Anderson, C.
    et al.
    Svensson, .
    Sjögren, F.
    Andersson, T.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Human in vivo microdialysis technique can be used to measure cytokines in contact reactions.1995In: Current Problems in Dermatology, ISSN 1421-5721, E-ISSN 1662-2944, Vol. 23, p. 121-130Article in journal (Refereed)
  • 28.
    Andersson, Fredrik
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Skoglund, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Viktorsson, Jan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    Ainegren, Mats
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Quality Technology and Management, Mechanical Engineering and Mathematics.
    A Portable Douglas Bag System2015In: Congress Proceedings: ICSNS 2015 / [ed] Hakkarainen Anni, Lindinger Stefan, Linnamo Vesa, 2015, p. 59-Conference paper (Refereed)
  • 29.
    Andersson, Mats
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Knutsson, Hans
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Kronander, Torbjorn
    Velocity Adaptive Filtered Angiography1999Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    A method of imaging a blood vessel in a body using X-rays and an injectable contrast medium is described. The contrast medium is injected into the body, and signals constituted by an X-ray image sequence depicting X-ray attenuation values is recorded. The X-ray attenuated values in each spaced-time neighborhood are combined in a way that is dependent on the processed image sequence and separately established for each neighborhood, and separating, from background and vessel signals, flow signals having energy contributions mainly in an area of frequency domain bounded by surfaces corresponding to threshold velocities separately established for each neighborhood, which surfaces are shifted a specified amount along a temporal frequency axis.

  • 30. Andersson, R
    et al.
    Loyd, Dan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Pressure sensed non-invasively directly on the extra corporeal bloodline tube2001In: PROCEEDINGS OF THE 23RD ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-4: BUILDING NEW BRIDGES AT THE FRONTIERS OF ENGINEERING AND MEDICINE, 2001, Vol. 23, p. 3179-3181Conference paper (Refereed)
    Abstract [en]

    To clinically measure blood pressure at extra corporeal bloodlines involves a hazard due to the infection risk and a risk for thrombosis formation. The aim was to design a non-invasive pressure sensor, measuring directly on a tube section. A modified tube cross-section was used to improve sensitivity. Using the developed sensing principle, a consistent relation (r=0.999) was obtained between pressure and output signal. The output was stable and an acceptable drift within the temperature-range. The method shows great promise for applications in monitoring of the dialysis process.

  • 31. Andersson, T.
    et al.
    Anderson, C.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Human in vivo cutaneous microdialysis: Estimation of histamine release in cold urticaria.1995In: Acta Dermato-Venereologica, ISSN 0001-5555, E-ISSN 1651-2057, no 75, p. 343-347Article in journal (Refereed)
    Abstract [en]

    A novel bioanalytical in vivo sampling technique, cutaneous microdialysis, was used to follow the chronology of skin histamine release in 3 patients with cold urticaria and in 2 healthy volunteers. Laser Doppler perfusion imaging was used simultaneously to monitor the skin circulatory response. Microdialysis samples were collected at 10-min intervals and analysed by radioimmunoassay technique. Fifty minutes after probe insertion, the ventral forearm skin in the area of the dialysis membrane was provoked for 5-15 min with a 25 x 40 mm ice cube covered with plastic foil. In the cold urticaria patients, an up to 80-fold increase of histamine was observed, with peak levels 20-30 min after challenge. Histamine levels then fell to reach "baseline" levels within 50 min. In the healthy subjects, the histamine increase was earlier, less pronounced and of shorter duration. Cutaneous microdialysis and laser Doppler imaging offer new possibilities for the chronological multiparameter assessment of inflammatory skin disorders in vivo.

  • 32.
    Andersson, Torbjörn
    Örebro University, School of Health and Medical Sciences.
    The development of ultrasound in radiology in Sweden2012In: Ultrasound in clinical diagnosis: from pioneering developments in Lund to global application in medicine / [ed] Bo Eklöf, Kjell Lindström, Stig Persson, Oxford: Oxford University Press, 2012, p. 121-128Chapter in book (Other academic)
  • 33.
    Antonsson, Johan
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    On optical methods for intracerebral measurements during stereotactic and functional neurosurgery: Experimental studies2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Radio frequency (RF) lesioning and deep brain stimulation (DBS) are the two prevailing surgical treatments for movement disorders within the field of stereotactic and functional neurosurgery. For RF-lesioning, a small volume of brain tissue is coagulated and knowledge of the lesion size and growth is of great importance for the safety and outcome of the procedure. This thesis deals with adapting the laser Doppler perfusion monitoring (LDPM) technique for measurements in brain tissue during RF-lesioning. The relation between LDPM signal changes and developed lesion size was investigated. LDPM measurements were evaluated both in vitro (albumin protein solution) and in vivo in the porcine brain during RF-lesioning corresponding to a bilateral thalamotomy in man. The investigated signals from the LDPI measurements can be used for following the lesioning time course and to detect if a lesion was created, both in vitro and in the animal model. For the albumin model, both the total backscattered light intensity and the perfusion signal can be used as markers for estimating the final coagulation size, while in the animal model this conclusion was not statistical verified.

    Independent on surgical method, RF-lesioning or DBS, intracerebral guidance is an important aspect within stereotactic and functional neurosurgery. To increase the accuracy and precision of reaching the correct target, different methods for intracerebral guidance exist, such as microelectrode recording and impedance methods. In this thesis, the possibility of developing an optical intracerebral guidance method has been investigated. Diffuse reflectance spectroscopy served as technology and all measurements were performed stereotactically in both porcine and human brain. Measurements of white and gray matter showed large differences, with higher reflectivity for white brain matter, both in porcine and in human brain. For the human measurements during DBS-implants, large differences between white matter and functional targets were found. Additionally, differences between native and lesioned porcine brain matter were detected. Both studies support the idea of using diffuse reflectance spectroscopy for developing an intracerebral guidance method.

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  • 34.
    Anund, Anna
    et al.
    Swedish National Road and Transport Research Institute.
    Hjälmdahl, Magnus
    Swedish National Road and Transport Research Institute.
    Evaluation of a sleepiness warning system: a test truck study2009Report (Other academic)
    Abstract [en]

    Sleep related crashes have received increasing attention over the past decade. Driver support systems that are able to detect sleepiness and warn the driver could be a potential countermeasure to reduce sleepiness related crashes. The aim of this study was to evaluate a warning system in an experimental investigation performed in a real time car driving application. An additional aim was also to examine the suitability of using an experimental vehicle at test track for evaluation of a sleepiness warning system. The modalities used for warning was a combination of sound, vibrations in belt and spoken messages. In addition a hand worn confirmation button was used. In total 40 participants drove at a closed test track during night (00h-05h). They were instructed to sleep between 01.00 and 07.00 for two nights prior to the night of the experiment. The design of the study was a between group, with 10 participants in each group. The four different groups experienced one of the following: A: No warning - baseline; B: SENSATION warning system with an early trigger; C: SENSATION warning system with a late trigger; D: Feedback (DMS - Siemens) and warning with a late trigger. The trigger of the warnings was based on observer registrations of the driver and driver behaviour. The drivers were instructed to drive a distance of 110 kilometres. The car was a Volvo 850, equipped with sensors in order to measure driving behaviour (lateral position, speed, steering wheel angle). As sleepiness indicators blink duration was used (mean and sd), measured with EOG. After the drive the participants answered a questionnaire. The experiment focused on comprehension, usability, effectiveness, and acceptance.

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  • 35.
    Anund, Anna
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Kircher, Katja
    Swedish National Road and Transport Research Institute, Traffic and road users, Human-vehicle-transport system interaction.
    Advantages and disadvantages of different methods to evaluate sleepiness warning systems2009Report (Other academic)
    Abstract [en]

    This is a methodological paper with the aim to discuss pros and cons related to different tools and environments when evaluating the effect of warnings given to sleepy drivers. There is no simple answer to the question which platform is most suitable. It depends on the research question asked, and it is possible that different aspects of the problem should be approached with different methods. A driving simulator has clear advantages when high control and repeatability are paramount. A simulator can also be used when the driver has to be put into a potentially dangerous scenario. How ecologically valid the results obtained from a simulator in fact are depends very much on the fidelity of the simulator. A test track study is based on real driving and should have a higher degree of ecological validity. On the other hand, the test track most often consists of an unrealistic environment. For assessing the prevalence of drowsy driving in real traffic, and in order to investigate what drivers actually do when they receive a sleepiness warning, it is absolutely necessary to study their natural behaviour when they go about their daily routines. Here field operational tests or naturalistic driving studies are most suitable. A disadvantage is the lack of control.

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  • 36.
    Applegate, Matthew B.
    et al.
    Boston Univ., United States.
    Karrobi, Kavon
    Boston Univ., United States.
    Angelo Jr., Joseph P.
    Univ. de Strasbourg, France.
    Austin, Wyatt M.
    The Univ. of Maine, United States.
    Tabassum, Syeda M.
    Boston Univ., United States.
    Aguénounon, Enagnon
    Univ. de Strasbourg, France.
    Tilbury, Karissa
    The Univ. of Maine, United States.
    Saager, Rolf B.
    Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Faculty of Science & Engineering.
    Gioux, Sylvain
    Univ. de Strasbourg, France.
    Roblyer, Darren M.
    Boston Univ., United States.
    OpenSFDI: an open-source guide for constructing a spatial frequency domain imaging system2020In: Journal of Biomedical Optics, ISSN 1083-3668, E-ISSN 1560-2281, Vol. 25, no 1Article in journal (Refereed)
    Abstract [en]

    Significance: Spatial frequency domain imaging (SFDI) is a diffuse optical measurement technique that can quantify tissue optical absorption (μa) and reduced scattering (μ0 s) on a pixelby-pixel basis. Measurements of μa at different wavelengths enable the extraction of molar concentrations of tissue chromophores over a wide field, providing a noncontact and label-free means to assess tissue viability, oxygenation, microarchitecture, and molecular content. We present here openSFDI: an open-source guide for building a low-cost, small-footprint, threewavelength SFDI system capable of quantifying μa and μ0 s as well as oxyhemoglobin and deoxyhemoglobin concentrations in biological tissue. The companion website provides a complete parts list along with detailed instructions for assembling the openSFDI system. Aim: We describe the design of openSFDI and report on the accuracy and precision of optical property extractions for three different systems fabricated according to the instructions on the openSFDI website. Approach: Accuracy was assessed by measuring nine tissue-simulating optical phantoms with a physiologically relevant range of μa and μ0 s with the openSFDI systems and a commercial SFDI device. Precision was assessed by repeatedly measuring the same phantom over 1 h. Results: The openSFDI systems had an error of 0 6% in μa and −2 3% in μ0 s, compared to a commercial SFDI system. Bland–Altman analysis revealed the limits of agreement between the two systems to be 0.004 mm−1 for μa and −0.06 to 0.1 mm−1 for μ0 s. The openSFDI system had low drift with an average standard deviation of 0.0007 mm−1 and 0.05 mm−1 in μa and μ0 s, respectively. Conclusion: The openSFDI provides a customizable hardware platform for research groups seeking to utilize SFDI for quantitative diffuse optical imaging.

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  • 37.
    Arvidsson, Daniel
    et al.
    University of Gothenburg.
    Fridolfsson, Jonatan
    University of Gothenburg.
    Börjesson, Mats
    University of Gothenburg.
    Andersen, Lars Bo
    Western Norway University of Applied Sciences, Campus Sogndal, Norway..
    Ekblom, Örjan
    Swedish School of Sport and Health Sciences, GIH, Department of Sport and Health Sciences, Åstrand Laboratory of Work Physiology.
    Dencker, Magnus
    Lund University.
    Brønd, Jan Christian
    University of Southern Denmark, Odense, Denmark.
    Re-examination of accelerometer data processing and calibration for the assessment of physical activity intensity.2019In: Scandinavian Journal of Medicine and Science in Sports, ISSN 0905-7188, E-ISSN 1600-0838, Vol. 29, no 10, p. 1442-1452Article in journal (Refereed)
    Abstract [en]

    This review reexamines use of accelerometer and oxygen uptake data for assessment of activity intensity. Accelerometers capture mechanical work, while oxygen uptake captures the energy cost of this work. Frequency filtering needs to be considered when processing acceleration data. A too restrictive filter attenuates the acceleration signal for walking and, to a higher degree, for running. This measurement error affects shorter (children) more than taller (adults) individuals due to their higher movement frequency. Less restrictive filtering includes more movement related signals and provide measures that better capture mechanical work, but may include more noise. An optimal filter cut-point is determined where most relevant acceleration signals are included. Further, accelerometer placement affects what part of mechanical work being captured. While the waist placement captures total mechanical work and therefore contributes to measures of activity intensity equivalent by age and stature, the thigh and wrist placements capture more internal work and do not provide equivalent measures. Value calibration of accelerometer measures is usually performed using measured oxygen uptake with the metabolic equivalent of task (MET) as reference measure of activity intensity. However, the use of MET is not stringent and is not a measure of activity intensity equivalent by age and stature. A candidate measure is the mass-specific net oxygen uptake, VO2 net (VO2 tot - VO2 stand). To improve measurement of physical activity intensity using accelerometers, research developments are suggested concerning processing of accelerometer data, use of energy expenditure as reference for activity intensity, and calibration procedure with absolute versus relative intensity. This article is protected by copyright. All rights reserved.

  • 38.
    Asan, Noor Badariah
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Univ Tekn Malaysia Melaka, Fac Elect & Comp Engn, Durian Tunggal 76100, Malaysia.
    Hassan, Emadeldeen
    Umea Univ, Dept Comp Sci, S-90187 Umea, Sweden;Menoufia Univ, Dept Elect & Elect Commun, Menoufia 32952, Egypt.
    Perez, Mauricio David
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Shah, Syaiful Redzwan Mohd
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Velander, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Blokhuis, Taco J.
    Maastricht Univ, Dept Surg, Med Ctr, NL-6229 HX Maastricht, Netherlands.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication. ¨.
    Augustine, Robin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Assessment of Blood Vessel Effect on Fat-Intrabody Communication Using Numerical and Ex-Vivo Models at 2.45 GHZ2019In: IEEE Access, E-ISSN 2169-3536, Vol. 7, p. 89886-89900Article in journal (Refereed)
    Abstract [en]

    The potential offered by the intra-body communication (IBC) over the past few years has resulted in a spike of interest for the topic, specifically for medical applications. Fat-IBC is subsequently a novel alternative technique that utilizes fat tissue as a communication channel. This work aimed to identify such transmission medium and its performance in varying blood-vessel systems at 2.45 GHz, particularly in the context of the IBC and medical applications. It incorporated three-dimensional (3D) electromagnetic simulations and laboratory investigations that implemented models of blood vessels of varying orientations, sizes, and positions. Such investigations were undertaken by using ex-vivo porcine tissues and three blood-vessel system configurations. These configurations represent extreme cases of real-life scenarios that sufficiently elucidated their principal influence on the transmission. The blood-vessel models consisted of ex-vivo muscle tissues and copper rods. The results showed that the blood vessels crossing the channel vertically contributed to 5.1 dB and 17.1 dB signal losses for muscle and copper rods, respectively, which is the worst-case scenario in the context of fat-channel with perturbance. In contrast, blood vessels aligned-longitudinally in the channel have less effect and yielded 4.5 dB and 4.2 dB signal losses for muscle and copper rods, respectively. Meanwhile, the blood vessels crossing the channel horizontally displayed 3.4 dB and 1.9 dB signal losses for muscle and copper rods, respectively, which were the smallest losses among the configurations. The laboratory investigations were in agreement with the simulations. Thus, this work substantiated the fat-IBC signal transmission variability in the context of varying blood vessel configurations.

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  • 39. Asan, Noor Badariah
    et al.
    Redzwan, Syaiful
    Rydberg, Anders
    Augustine, Robin
    Noreland, Daniel
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Hassan, Emadeldeen
    Umeå University, Faculty of Science and Technology, Department of Computing Science. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Voigt, Thiemo
    Human Fat Tissue: A Microwave Communication Channel2017In: 2017 First IEEE MTT-S International Microwave Bio Conference (IMBIOC), IEEE, 2017Conference paper (Refereed)
    Abstract [en]

    In this paper, we present an approach for communication through human body tissue in the R-band frequency range. This study examines the ranges of microwave frequencies suitable for intra-body communication. The human body tissues are characterized with respect to their transmission properties using simulation modeling and phantom measurements. The variations in signal coupling with respect to different tissue thicknesses are studied. The simulation and phantom measurement results show that electromagnetic communication in the fat layer is viable with attenuation of approximately 2 dB per 20 mm.

  • 40.
    Ashkir, Zakariye
    et al.
    Univ Oxford, England.
    Myerson, Saul
    Univ Oxford, England.
    Neubauer, Stefan
    Univ Oxford, England.
    Carlhäll, Carljohan
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Ebbers, Tino
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Raman, Betty
    Univ Oxford, England.
    Four-dimensional flow cardiac magnetic resonance assessment of left ventricular diastolic function2022In: Frontiers in Cardiovascular Medicine, E-ISSN 2297-055X, Vol. 9, article id 866131Article, review/survey (Refereed)
    Abstract [en]

    Left ventricular diastolic dysfunction is a major cause of heart failure and carries a poor prognosis. Assessment of left ventricular diastolic function however remains challenging for both echocardiography and conventional phase contrast cardiac magnetic resonance. Amongst other limitations, both are restricted to measuring velocity in a single direction or plane, thereby compromising their ability to capture complex diastolic hemodynamics in health and disease. Time-resolved three-dimensional phase contrast cardiac magnetic resonance imaging with three-directional velocity encoding known as 4D flow CMR is an emerging technology which allows retrospective measurement of velocity and by extension flow at any point in the acquired 3D data volume. With 4D flow CMR, complex aspects of blood flow and ventricular function can be studied throughout the cardiac cycle. 4D flow CMR can facilitate the visualization of functional blood flow components and flow vortices as well as the quantification of novel hemodynamic and functional parameters such as kinetic energy, relative pressure, energy loss and vorticity. In this review, we examine key concepts and novel markers of diastolic function obtained by flow pattern analysis using 4D flow CMR. We consolidate the existing evidence base to highlight the strengths and limitations of 4D flow CMR techniques in the surveillance and diagnosis of left ventricular diastolic dysfunction.

  • 41.
    Ask, Per
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Edwall, G
    Johansson, K E
    Tibbling, Lita
    On the use of monocrystalline antimony pH electrodes in gastro-oesophageal functional disorders.1982In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 20, no 3, p. 383-389Article in journal (Refereed)
    Abstract [en]

    Monocrystalline antimony electrodes have been shown to be suitable for thein vivo determination of pH in blood, tissue and in the upper gastro-intestinal canal. Thanks to their small dimensions it has been possible to mount them into conventional manometry catheters for oesophageal investigation. The monocrystalline antimony pH electrode has several advantages over the conventional pH glass electrode; better accuracy, shorter rise time, smaller dimensions. The monocrystalline antimony electrode has been used for long-term registration of gastro-oesophageal reflux, for the oesophageal acid clearing test and for identification of the pH gradient zone between the gastric and oesophageal mucosa. Its use in combination with pressure sensors has added a new dimension to the diagnosis of functional disorders in the gastro-oesophageal region.

  • 42.
    Ask, Per
    et al.
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Skogh, Marcus
    Öberg, Åke
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Undersökning av EKG-elektroners elektriska och mekaniska långtidsegenskaper1974Report (Other academic)
  • 43.
    Asklöf, Madeleine
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping.
    Kjölhede, Preben
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping.
    Borendal Wodlin, Ninnie
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping. Linköping University, Department of Clinical and Experimental Medicine.
    Nilsson, Lena
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping.
    Bioelectrical impedance analysis; a new method to evaluate lymphoedema, fluid status, and tissue damage after gynaecological surgery - A systematic review2018In: European Journal of Obstetrics, Gynecology, and Reproductive Biology, ISSN 0301-2115, E-ISSN 1872-7654, Vol. 228, p. 111-119Article, review/survey (Refereed)
    Abstract [en]

    The aim of this descriptive review is to summarise the current knowledge of non-invasive bioelectrical impedance analysis (BIA) used with gynaecological surgical patients in regard to postoperative development of lymphoedema and determination of perioperative fluid balance, and as a prognostic factor in cancer mortality and a predictor of postoperative complications. The databases PubMed, MEDLINE, Scopus Web of Science, the Cochrane Library, and reference lists of selected articles were searched for relevant articles published during the period January 2008-April 2018. Only papers published in English were retrieved. Thirty-seven articles were evaluated. Where gynaecological studies were lacking, studies with a study population from neighbouring clinical fields were used instead. Studies on the clinical use of BIA with gynaecological surgical patients were divided into three categories: the postoperative development of lower limb lymphoedema (n = 7), perioperative hydration measuring (n = 3), and the BIA parameter phase angle as a prognostic factor in cancer survival and as predictive for postoperative complications (n = 6). Of these 16 studies only three used a pure gynaecological study population. Three different methods of BIA were used in these articles: single frequency-BIA, multifrequency-BIA and bioimpedance spectroscopy. BIA was found to detect lymphoedema with a sensitivity of 73% and a specificity of 84%. Studies indicated that BIA was able to detect lower limb lymphoedema at an early stage even before it became clinically detectable. During postoperative hydration measurements, an increase in extracellular fluid volume and extracellular fluid volume in relation to total body fluid volume, as well as a decrease in phase angle, were associated with higher frequencies of postoperative complications. Moreover, low values for the phase angle have been associated with increased mortality in cancer patients. However, the number of studies in this field was limited. From our review, BIA seems to be a useful tool for use in the clinical setting of the gynaecological surgical patient. The theoretical approach of using bioelectrical impedance values to measure the fluid distribution in the body compartments offers wide opportunities in the clinical setting. However, so far, all studies have set up cut-off limits within the study population, and reference values for a general population need to be defined. There are also rather few studies on a gynaecological study population. Hence, there is a need for further studies within gynaecological surgery focusing on early detection of lower limb lymphoedema, perioperative fluid balance, and postoperative complications in order to establish the value of BIA in clinical praxis. (C) 2018 Elsevier B.V. All rights reserved.

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  • 44. Aslund, Magnus
    et al.
    Fredenberg, Erik
    KTH, School of Engineering Sciences (SCI), Physics, Physics of Medical Imaging.
    Telman, M.
    Danielsson, Mats
    KTH, School of Engineering Sciences (SCI), Physics, Physics of Medical Imaging.
    Detectors for the future of X-ray imaging2010In: Radiation Protection Dosimetry, ISSN 0144-8420, E-ISSN 1742-3406, Vol. 139, no 1-3, p. 327-333Article in journal (Refereed)
    Abstract [en]

    In recent decades, developments in detectors for X-ray imaging have improved dose efficiency. This has been accomplished with for example, structured scintillators such as columnar CsI, or with direct detectors where the X rays are converted to electric charge carriers in a semiconductor. Scattered radiation remains a major noise source, and fairly inefficient anti-scatter grids are still a gold standard. Hence, any future development should include improved scatter rejection. In recent years, photon-counting detectors have generated significant interest by several companies as well as academic research groups. This method eliminates electronic noise, which is an advantage in low-dose applications. Moreover, energy-sensitive photon-counting detectors allow for further improvements by optimising the signal-to-quantum-noise ratio, anatomical background subtraction or quantitative analysis of object constituents. This paper reviews state-of-the-art photon-counting detectors, scatter control and their application in diagnostic X-ray medical imaging. In particular, spectral imaging with photon-counting detectors, pitfalls such as charge sharing and high rates and various proposals for mitigation are discussed.

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  • 45.
    Asplund, Maria
    KTH, School of Technology and Health (STH), Neuronic Engineering.
    Conjugated Polymers for Neural Interfaces: Prospects, possibilities and future challenges2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

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

     

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

     

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

     

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

     

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

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  • 46.
    Augustine, Robin
    Uppsala University.
    A Non-invasive Skin Burn Degree Analysis Using Microwaves2015Conference paper (Other academic)
  • 47.
    Augustine, Robin
    Uppsala University.
    Application of UWB Radar Techniques for Imaging cranial vaults2015Conference paper (Other academic)
  • 48.
    Augustine, Robin
    Uppsala University.
    Microwave head phantoms for post-craniotomy and BMP based implant2015Conference paper (Other academic)
  • 49.
    Augustine, Robin
    Uppsala University.
    Microwave studies on Beta Tricalcium Phosphate Bioceramics for medical application2006Conference paper (Refereed)
  • 50.
    Augustine, Robin
    Uppsala University.
    SRR Antenna for Biomedical Application2016Conference paper (Refereed)
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