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  • 1.
    Aagerup, Ulf
    et al.
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Centrum för innovations-, entreprenörskaps- och lärandeforskning (CIEL).
    Frank, Anna-Sofia
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Hultqvist, Evelina
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    The persuasive effects of emotional green packaging claims2019Ingår i: British Food Journal, ISSN 0007-070X, E-ISSN 1758-4108, Vol. 121, nr 12, s. 3233-3246Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose - The purpose of this paper is to investigate the effects of rational green packaging claims vs emotional green packaging claims on consumers' purchase propensity for organic coffee.

    Design/methodology/approach - Three within-subjects experiment were carried out (N=87, N=245, N=60). The experimental design encompasses packaging with rational green claims, emotional green claims, as well as a neutral (control) claim. Measured variables are introduced to assess participants' environmental commitment and information processing ability. A manipulated between-subjects variable is introduced to test how distraction interacts with preference for the claims.

    Findings - Overall, consumers prefer products with green claims over those with neutral (control) claims, and products with emotional green claims to those with rational green claims. The studies also reveal that this effect is moderated by participants' environmental commitment, information processing ability and by distraction. The findings were statistically significant (p<0.05).

    Research limitations/implications - As a lab experiment, the study provides limited generalizability and external validity. Practical implications - For most organic FMCG products, it is advisable to employ emotional packaging claims.

    Social implications - The presented findings provide marketers with tools to influence consumer behavior toward sustainable choices.

    Originality/value - The paper validates previous contributions on the effects of product claim types, and extends them by introducing comprehensive empirical data on all the Elaboration Likelihood Model's criteria for rational decision-making; motivation, opportunity and ability.

  • 2.
    Aagerup, Ulf
    et al.
    Högskolan i Halmstad, Centrum för innovations-, entreprenörskaps- och lärandeforskning (CIEL).
    Frank, Anna-Sofia
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Hultqvist, Evelina
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    The persuasive effects of emotional green packaging claims2019Ingår i: British Food Journal, ISSN 0007-070X, E-ISSN 1758-4108, Vol. 121, nr 12, s. 3233-3246Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose - The purpose of this paper is to investigate the effects of rational green packaging claims vs emotional green packaging claims on consumers' purchase propensity for organic coffee.

    Design/methodology/approach - Three within-subjects experiment were carried out (N=87, N=245, N=60). The experimental design encompasses packaging with rational green claims, emotional green claims, as well as a neutral (control) claim. Measured variables are introduced to assess participants' environmental commitment and information processing ability. A manipulated between-subjects variable is introduced to test how distraction interacts with preference for the claims.

    Findings - Overall, consumers prefer products with green claims over those with neutral (control) claims, and products with emotional green claims to those with rational green claims. The studies also reveal that this effect is moderated by participants' environmental commitment, information processing ability and by distraction. The findings were statistically significant (p<0.05).

    Research limitations/implications - As a lab experiment, the study provides limited generalizability and external validity. Practical implications - For most organic FMCG products, it is advisable to employ emotional packaging claims.

    Social implications - The presented findings provide marketers with tools to influence consumer behavior toward sustainable choices.

    Originality/value - The paper validates previous contributions on the effects of product claim types, and extends them by introducing comprehensive empirical data on all the Elaboration Likelihood Model's criteria for rational decision-making; motivation, opportunity and ability.

  • 3.
    Aare, Magnus
    et al.
    KTH, Skolan för teknik och hälsa (STH), Neuronik.
    Kleiven, Svein
    KTH, Skolan för teknik och hälsa (STH), Neuronik.
    Evaluation of head response to ballistic helmet impacts, using FEM2003Konferensbidrag (Refereegranskat)
  • 4.
    Aare, Magnus
    et al.
    KTH, Skolan för teknik och hälsa (STH), Neuronik.
    Kleiven, Svein
    KTH, Skolan för teknik och hälsa (STH), Neuronik.
    Halldin, Peter
    KTH, Skolan för teknik och hälsa (STH), Neuronik.
    Proposed global injury thresholds for oblique helmet impacts2003Konferensbidrag (Refereegranskat)
  • 5.
    Abedan Kondori, Farid
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Yousefi, Shahrouz
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Liu, Li
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Active human gesture capture for diagnosing and treating movement disorders2013Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Movement disorders prevent many people fromenjoying their daily lives. As with other diseases, diagnosisand analysis are key issues in treating such disorders.Computer vision-based motion capture systems are helpfultools for accomplishing this task. However Classical motiontracking systems suffer from several limitations. First theyare not cost effective. Second these systems cannot detectminute motions accurately. Finally they are spatially limitedto the lab environment where the system is installed. In thisproject, we propose an innovative solution to solve the abovementionedissues. Mounting the camera on human body, webuild a convenient, low cost motion capture system that canbe used by the patient in daily-life activities. We refer tothis system as active motion capture, which is not confinedto the lab environment. Real-time experiments in our labrevealed the robustness and accuracy of the system.

    Ladda ner fulltext (pdf)
    Active Human Gesture Capture for Diagnosing and Treating Movement Disorders
  • 6.
    Abou-Hamad, Eliana
    Luleå tekniska universitet, Institutionen för ekonomi, teknik, konst och samhälle.
    A design solution for prevention of pressure ulcers: A sensor driven bedding for hospital beds that detect pressure2021Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Denna rapport handlar om prevention av trycksår (liggsår). Examensarbetet av en student vidLuleå Tekniska Universitet inom Teknisk design under våren 2021. Trycksår är ett besvärligtoch jobbigt problem som finns överallt inom sjukvården. De uppstår på människor som liggereller sitter i samma position en längre tid, där kroppens tyngd skapar ett tryck mot underlaget.Det bidrar till att blodgenomflödet i hud och underhudsvävnader minskar eller upphör vilketleder till trycksår.

    Intresset för arbetet kom till efter att ha fått kontakt med Per Söderberg, där han berättadeom uppdraget han arbetat med och inte kunnat släppa, efter att ha gått i pension. Uppdragethandlade om att läka och förebygga trycksår genom en sängvagga CUNIDORM som Perskapat. Per fastnade med sin idé på grund av dålig design och sökte sig vidare efter någon somkunde se uppdraget från ett nytt perspektiv. Syftet med projektet blev att hitta en lösning somförebygger trycksår från att uppstå.

    För att lösa problemet användes en iterativ designprocess PCDIO (Planning, Conceive,Design, Implement & Operate) som utfördes med HCD (Human-Centered design) somtankesätt eftersom lösningen är avsedd för människan. I början av processen genomfördeskontextfasen. Där bestämdes behoven genom intervjuer och forskning på nuläget. Störstabehoven som identifierades var behovet av att minska vändningar och granskningar avpatienterna. Granskning är den främsta metoden för att förebygga trycksår. Behovet av bramaterial identifierades då en orsak till trycksår var fukt och värme. Efter att användarbehovenupptäckts användes olika metoder inom ramarna av programmet Teknisk Designs för attskapa idéer och koncept.

    Det resulterade i tre koncept, luftmadrassen, skummadrassen med mekaniska armar ochmadrassen med sensorer. Koncepten utvärderades utifrån en designspecifikation där depoängsattes. Det koncept som uppfyllde kriterierna bäst med högst poäng blev det vinnandekonceptet.

    Resultatet blev SENSAI, madrassen som känner av patientens tyngd under en tidsperiod medhjälp av sensorer. Den detekterar vart trycket är som mest och hur skadligt det är. Genom attdetektera tryck och belastning kan potentiella trycksår upptäckas tidigare. Produkten har intetestats med hjälp av prototyper eller liknande på grund av pandemin och bristande tillgångtill material. Slutsatsen för detta projekt är att utföra fler tester och undersökningar.Förhoppningsvis kommer detta att ske som fortsatt arbete efter examensarbetets slut. 

  • 7.
    Abtahi, Farhad
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Towards Heart Rate Variability Tools in P-Health: Pervasive, Preventive, Predictive and Personalized2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Hjärtfrekvensvariabilitet (HRV) har senaste tiden rönt en hel del uppmärksamhet och flera teknikerför analys av HRV i tids- resp. frekvensområdet samt medels icke-linjära metoder har utvecklats.Det har visats att HRV kan användas för att övervaka det autonoma nervsystemet (ANS) blandannat för att upptäcka särskilt vagala störningar inom ANS. Minskad HRV förknippas med flerasjukdomar såsom diabetes, reumatoid artrit, depression, kronisk hjärtsjukdom och har ävenföreslagits som prediktor för dålig prognos och plötslig hjärtdöd. HRV är dock ännu inte allmäntaccepterat som ett kliniskt verktyg utan används främst inom forskning. Framsteg inomneuroimmunitetsområdet med ökad förståelse för sambandet mellan nerv- och immunsystem, haröppnat en nytt potentiell område för HRV-applikationer. Ett exempel är när systemiskinflammationoch autoimmun sjukdom primärt orsakas av låg vagal aktivitet, vilket kan upptäckas ochprognostiseras via minskad HRV. Denna avhandling är resultatet av flera tekniska utvecklingsstegoch explorativ forskning där HRV tillämpas i syfte att utveckla ett prognostiskt diagnostiskt verktygmed förebyggande potential. Huvudsyften har varit: 1) att utveckla ett prisvärt verktyg för eneffektiv och enkel analys av HRV 2) att studera sambandet mellan HRV och pro-inflammatoriskamarkörer och därigenom potentiellt återspegla graden av aktivitet i den kolinergaantiinflammatoriska effektorvägen 3) att utveckla datorprogramvara för ett biologisktåterkopplingssystem där individen med egen träning ökar sin vagala aktivitet vilket sedanåterspeglas i en ökad HRV. I denna sammanläggningsavhandling finns utförlig beskrivning av varjeingående studies metod och resultat artikar I-VI. I ramberättelsen presenteras en kortsammanfattning av metoder och resultat, grupperade efter ämne och sammanhang.Sammanfattningsvis visar resultaten att de utvecklade verktygen adekvat registrerar och analyserarHRV korrekt enkelt , samt att HRV kan påverkas av spel-träning. HRV i framtaget koncept harpotential att användas som ett skarpt prognostiskt verktyg, inte bara för traditionell vård med fokuspå sjukdom, utan också inom friskvård. Framtagna verktyg möjliggör tidig upptäckt av minskadHRV, snabb intervention och prevention. Spelifiering med seriöst spelande utgör en potentiellplattform som motiverar en träningsrutin och som genom återkoppling kan öka HRV och därmedvälmåendet.

    Ladda ner fulltext (pdf)
    Thesis
  • 8.
    Abtahi, Farhad
    et al.
    Karolinska Institutet.
    Anund, Anna
    Fors, Carina
    Seoane, Fernando
    Högskolan i Borås, Akademin för textil, teknik och ekonomi. Högskolan i Borås, Akademin för vård, arbetsliv och välfärd. Karolinska Institutet.
    Lindecrantz, Kaj
    Högskolan i Borås, Akademin för textil, teknik och ekonomi. Karolinska Institutet.
    Association of Drivers’ sleepiness with heart rate variability. A Pilot Study with Drivers on Real Road2017Konferensbidrag (Övrigt vetenskapligt)
  • 9. Abtahi, Farhad
    et al.
    Forsman, Mikael
    Diaz-Olivares, Jose A.
    KTH, Skolan för teknik och hälsa (STH). KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Ergonomi.
    Yang, Liyun
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Ergonomi.
    Lu, Ke
    KTH, Skolan för teknik och hälsa (STH).
    Eklund, Jörgen
    KTH, Skolan för teknik och hälsa (STH).
    Lindecrantz, Kaj
    KTH, Skolan för teknik och hälsa (STH).
    Seoane, Fernando
    Teriö, Heikki
    Mediavilla Martinez, Cesar
    Aso, Santiago
    Tiemann, Christian
    Big Data & Wearable Sensors Ensuring Safety and Health @Work2017Ingår i: GLOBAL HEALTH 2017, The Sixth International Conference on Global Health Challenges, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

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

    Ladda ner fulltext (pdf)
    fulltext
  • 10.
    Abtahi, Farhad
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system. Karolinska Institutet, Sweden.
    Hilderman, Marie
    Bruchfeld, Annette
    Seoane, Fernando
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system. University of Borås, Sweden.
    Janerot-Sjöberg, Birgitta
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinsk bildteknik. Karolinska Institutet, Sweden.
    Lindecrantz, Kaj
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system. Karolinska Institutet, Sweden.
    Pro-inflammatory Blood Markers and Heart Rate Variability in Apnoea as a Reflection of Basal Vagal ToneManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

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

  • 11.
    Abtahi, Farhad
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Seoane, Fernando
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Lindecrantz, Kaj
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinska sensorer, signaler och system.
    Löfgren, Nils
    Elimination of ECG Artefacts in Foetal EEG Using Ensemble Average Subtraction and Wavelet Denoising Methods: A Simulation2014Ingår i: XIII Mediterranean Conference on Medical and Biological Engineering and Computing 2013, Springer, 2014, s. 551-554Konferensbidrag (Refereegranskat)
    Abstract [en]

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

  • 12.
    Adolfsson, Lars
    et al.
    Department of Orthopaedics, Institution of Surgery and Experimental medicine, Linköping University, 581 85, Linköping, Sweden.
    Hallgren, Hanna Björnsson
    Department of Orthopaedics, Institution of Surgery and Experimental medicine, Linköping University, 581 85, Linköping, Sweden.
    Tegner, Yelverton
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Hälsa, medicin och rehabilitering.
    Union of Scaphoid Waist Fractures in Adults Despite No or Minimal Immobilization: a Report of Five Cases2020Ingår i: SN Comprehensive Clinical Medicine, E-ISSN 2523-8973, Vol. 2, nr 4, s. 491-495Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Traditionally scaphoid waist fractures have been treated with a long period, 10–12 weeks, of immobilization in a plaster cast until radiological union. The long period of immobilization sometimes infers great discomfort for the patients. To avoid this, surgical treatment with screw fixation has for the last decade been advocated as an option also for undisplaced fractures. In this report, we present five cases with undisplaced scaphoid waist fractures that have healed both radiologically and clinically without any immobilization at all or after a very short period of protection in a cast. These observations challenge the current treatment guidelines.

  • 13.
    Aghanavesi, Somayeh
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Mikrodataanalys.
    Bergquist, Filip
    Nyholm, Dag
    Senek, Marina
    Memedi, Mevludin
    Motion sensor-based assessment of Parkinson’s disease motor symptoms during leg agility tests: results from levodopa challenge2020Ingår i: IEEE journal of biomedical and health informatics, ISSN 2168-2194, E-ISSN 2168-2208, Vol. 24, nr 1, s. 111-119, artikel-id 8637809Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Parkinson’s disease (PD) is a degenerative, progressive disorder of the central nervous system that mainly affects motor control. The aim of this study was to develop data-driven methods and test their clinimetric properties to detect and quantify PD motor states using motion sensor data from leg agility tests. Nineteen PD patients were recruited in a levodopa single dose challenge study. PD patients performed leg agility tasks while wearing motion sensors on their lower extremities. Clinical evaluation of video recordings was performed by three movement disorder specialists who used four items from the motor section of the Unified PD Rating Scale (UPDRS), the treatment response scale (TRS) and a dyskinesia score. Using the sensor data, spatiotemporal features were calculated and relevant features were selected by feature selection. Machine learning methods like support vector machines (SVM), decision trees and linear regression, using 10-fold cross validation were trained to predict motor states of the patients. SVM showed the best convergence validity with correlation coefficients of 0.81 to TRS, 0.83 to UPDRS #31 (body bradykinesia and hypokinesia), 0.78 to SUMUPDRS (the sum of the UPDRS items: #26-leg agility, #27-arising from chair and #29-gait), and 0.67 to dyskinesia. Additionally, the SVM-based scores had similar test-retest reliability in relation to clinical ratings. The SVM-based scores were less responsive to treatment effects than the clinical scores, particularly with regards to dyskinesia. In conclusion, the results from this study indicate that using motion sensors during leg agility tests may lead to valid and reliable objective measures of PD motor symptoms.

    Ladda ner fulltext (pdf)
    fulltext
  • 14.
    Aghanavesi, Somayeh
    et al.
    Högskolan Dalarna, Akademin Industri och samhälle, Mikrodataanalys.
    Memedi, Mevludin
    Högskolan Dalarna, Akademin Industri och samhälle, Datateknik.
    Dougherty, Mark
    Högskolan Dalarna, Akademin Industri och samhälle, Mikrodataanalys.
    Nyholm, Dag
    Westin, Jerker
    Högskolan Dalarna, Akademin Industri och samhälle, Datateknik.
    Verification of a method for measuring Parkinson’s disease related temporal irregularity in spiral drawings2017Ingår i: Sensors, E-ISSN 1424-8220, Vol. 17, nr 10, artikel-id 2341Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Parkinson's disease (PD) is a progressive movement disorder caused by the death of dopamine-producing cells in the midbrain. There is a need for frequent symptom assessment, since the treatment needs to be individualized as the disease progresses. The aim of this paper was to verify and further investigate the clinimetric properties of an entropy-based method for measuring PD-related upper limb temporal irregularities during spiral drawing tasks. More specifically, properties of a temporal irregularity score (TIS) for patients at different stages of PD, and medication time points were investigated. Nineteen PD patients and 22 healthy controls performed repeated spiral drawing tasks on a smartphone. Patients performed the tests before a single levodopa dose and at specific time intervals after the dose was given. Three movement disorder specialists rated videos of the patients based on the unified PD rating scale (UPDRS) and the Dyskinesia scale. Differences in mean TIS between the groups of patients and healthy subjects were assessed. Test-retest reliability of the TIS was measured. The ability of TIS to detect changes from baseline (before medication) to later time points was investigated. Correlations between TIS and clinical rating scores were assessed. The mean TIS was significantly different between healthy subjects and patients in advanced groups (p-value = 0.02). Test-retest reliability of TIS was good with Intra-class Correlation Coefficient of 0.81. When assessing changes in relation to treatment, TIS contained some information to capture changes from Off to On and wearing off effects. However, the correlations between TIS and clinical scores (UPDRS and Dyskinesia) were weak. TIS was able to differentiate spiral drawings drawn by patients in an advanced stage from those drawn by healthy subjects, and TIS had good test-retest reliability. TIS was somewhat responsive to single-dose levodopa treatment. Since TIS is an upper limb high-frequency-based measure, it cannot be detected during clinical assessment.

    Ladda ner fulltext (pdf)
    fulltext
  • 15.
    Agnvall, Beatrix
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Bélteky, Johan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Jensen, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Brain size is reduced by selectionfor tameness in Red Junglefowl–correlated effects in vital organs2017Ingår i: Scientific Reports, E-ISSN 2045-2322, Vol. 7, artikel-id 3306Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    During domestication animals have undergone changes in size of brain and other vital organs. We hypothesize that this could be a correlated effect to increased tameness. Red Junglefowl (ancestors of domestic chickens) were selected for divergent levels of fear of humans for five generations. The parental (P0) and the fifth selected generation (S5) were culled when 48–54 weeks old and the brains were weighed before being divided into telencephalon, cerebellum, mid brain and optic lobes. Each single brain part as well as the liver, spleen, heart and testicles were also weighed. Brains of S5 birds with high fear scores (S5 high) were heavier both in absolute terms and when corrected for body weight. The relative weight of telencephalon (% of brain weight) was significantly higher in S5 high and relative weight of cerebellum was lower. Heart, liver, testes and spleen were all relatively heavier (% of body weight) in S5 high. Hence, selection for tameness has changed the size of the brain and other vital organs in this population and may have driven the domesticated phenotype as a correlated response.

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  • 16.
    Ahlström, Christer
    et al.
    Statens väg- och transportforskningsinstitut, Trafik och trafikant,TRAF, Samspel människa, fordon, transportsystem, MFT.
    Dukic, Tania
    Statens väg- och transportforskningsinstitut, Trafik och trafikant,TRAF, Samspel människa, fordon, transportsystem, MFT.
    Comparison of eye tracking systems with one and three cameras2011Ingår i: ACM International Conference Proceeding Series, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    When using eye movements to determine the state of a car driver it is important that the eye tracker is robust, unobtrusive, inexpensive and fully automatic. The objectives of this study are to compare the performance of a one-camera system with a three-camera system and to investigate if the accuracy and availability of the one-camera system is sufficient to monitor driver state. Data from 53 subjects were evaluated and the results indicate that there is not much difference between a single-camera system and a multi-camera system as long as the driver is looking straight ahead. However, with more peripheral gaze directions, the larger coverage that is provided by the additional cameras works in favour of the multi-camera system. © ACM 2010.

  • 17.
    Ahmed, Masud Omar
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik.
    Teststation för industriella UV-celler2019Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    GE Healthcare Bio-Sciences AB i Umeå tillverkar ett flertal system, ett av systemen är vätskekromatografen. Vätskekromatografen är en kemisk separationsmetod som använder sig av en UV-monitor, UV-detektor och en UV-cell för att mäta absorptionen av en lösning och framta koncentrationen av det eftersökta ämnet. På anläggningen i Umeå tillverkas två typer av UV-celler; laborationceller och industriceller. För labbcellerna har GE utvecklat en teststation som testar och utvärderar UV och flödesegenskaper samt lagrar data i GE:s egen produktionsdatabas, Prodas. Den befintliga stationen för industriceller är äldre och omodern, en utveckling behövs för att upprätthålla högre kvalité.

    Syftet med detta projekt är att uppdatera teststationen för industriella UV-celler till samma nivå som stationen för laborationsceller. Det primära målet är att konstruera och designa en teststation för industriella UV-celler som kan mäta tryck, flöde och absorption. Det sekundära målet är att upptäcka och om möjligt verkställa lösningar som kommer effektivisera och automatisera mätningarna.

    En prototyp av en teststation för industriella UV-celler baserat på den för laborationceller har framtagits, och består av en adapterlösning som används för att sammanlänka ljusbanan från monitorn genom flödescellen till detektorn. Prototypen kan enbart utföra absorption och läckagemätningar. Automatisering och effektivisering har utförts i form av scripts som används för att genomföra absorptions och läckagemätning. Teststationen kräver fortsatt vidareutveckling innan den kan används i produktionslinjen.

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  • 18.
    Ahnesjö, Anders
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Medicinsk strålningsvetenskap.
    Patient Dose Computation2014Ingår i: Comprehensive Biomedical Physics: Volume 9: Radiation Therapy Physics and Treatment Optimization / [ed] Anders Brahme, Amsterdam: Elsevier, 2014, s. 235-247Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Various dose calculation methods have been proposed to serve the needs in treatment planning of radiotherapy. Common to these are that they need a patient model to describe the interaction properties of the irradiated tissues, and a sufficiently accurate description of the incident radiation. This chapter starts with a brief review of the contexts in which patient dose calculations may serve, followed by a description of common methods for patient modelling and beam characterization. The focus is on external beam photon, but also partly covers particle beams like electrons and protons. The last section describes common approaches of varying complexity for dose calculations ranging from simple factor based models, more elaborate pencil and point kernel models, and finally summarizes some aspects of Monte Carlo and grid based methods.

  • 19.
    Ajaxon, Ingrid
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Holmberg, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Öhman Mägi, Caroline
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Fatigue life of a brushite cement under cyclic compressive loading2017Konferensbidrag (Refereegranskat)
  • 20.
    Ajaxon, Ingrid
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Holmberg, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Öhman Mägi, Caroline
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Persson, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Long-term degradation of brushite cements in three different liquids2016Konferensbidrag (Övrigt vetenskapligt)
  • 21.
    Akay, Altug
    KTH, Skolan för teknik och hälsa (STH), Hälso- och systemvetenskap, Systemsäkerhet och organisation.
    A Novel Method to Intelligently Mine Social Media to Assess Consumer Sentiment of Pharmaceutical Drugs2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

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

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

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  • 22.
    Al-Absi, Thabit
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Bioinformatik. Linköpings universitet, Tekniska högskolan.
    Efficient Characterization of Short Anelloviruses Fragments Found in Metagenomic Samples2012Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Some viral metagenomic serum samples contain a huge amount of Anellovirus, which is a genetically diverse family with a few conserved regions making it hard to efficiently characterize. Multiple sequence alignment of the Anelloviruses found in the sample must be constructed to get a clear picture of Anellovirus diversity and to identify stable regions. Using available multiple sequence alignment software directly on these fragments results in an MSA of a very poor quality due to their diversity, misaligned regions and low-quality regions present in the sequence.

    An efficient MSA must be constructed in order to characterize these Anellovirus present in the samples. Pairwise alignment is used to align one fragment to the database sequences at a time. The fragments are then aligned to the database sequences using the start and end position from the pairwise alignment results. The algorithm will also exclude non-aligned portions of the fragments, as these are very hard to handle properly and are often products of misassembly or chimeric sequenced fragments. Other tools to aid further analysis were developed, such as finding a non-overlapping window that contains the most fragments, find consensus of the alignment and extract any regions from the MSA for further analysis.

    An MSA was constructed with a high percent of correctly aligned bases compared to an MSA constructed using MSA softwares. The minimal number of genomes found in the sampled sequence was found as well as a distribution of the fragments along the database sequence. Moreover, highly conserved region and the window containing most fragments were extracted from the MSA and phylogenetic trees were constructed for these regions. 

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  • 23.
    Albano, Amanda
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Exploratory statistical study of long-term variability in echocardiographic indices (echocardiovariability) in healthy and diseased1987Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Hjärtfrekvensvariabilitet, HRV, är ett väl utforskat område sedan några årtionden tillbaka. Svängningarna i hjärtfrekvensen studeras över tidsperioder av några minuter upp till 24 timmar och mäts med elektrokardiografi, EKG. Från det har man kunnat sluta sig till att signalen för hjärtfrekvensen oscillerar enligt signalen för andningen, kärlresistans etc.

    Den mest använda undersökningsmetoden på hjärtat utförs med ultraljud, ekokardiografi. De intressanta variablerna mäts en i taget och för ett hjärtslag åt gången. Med inspiration från studierna av HRV fokuserar det här projektet på några av variablerna som mäts med ultraljud, men som tidsserier och simultant mätta. De intressanta variablerna är tagna från hjärtmuskeln och blodflödet i den vänstra delen av hjärtat. Mätningarna görs över två minuter. För att komplettera dessa variabler mäts de välkända variablerna HR och Resp med EKG och läggs till analysen.

    Metoderna för att analysera datat är först av allt beskrivande statistik, såsom medelvärde och standardavvikelse. I ett andra steg görs en spektralanalys för att undersöka inom vilka frekvenser signalerna oscillerar. Genom koherens jämförs detta med spektrum för HR där de tre topparna har känt ursprung. Slutligen utförsen principalkomponentanalys, PCA, som en metod för att jämföra alla variabler samtidigt.

    Analyserna utförs på sju mätninger från fem (5) friska personer och fem mätningar från fyra (4) patienter med FAP (“Skelleftesjukan”). Variablerna undersöks och beskrivs först för de friska personerna, sedan jämförs de friska och sjuka personerna.

    Resultatet av studien visar att största delen av eko-variablerna oscillerar i enighet med andningen och hjärtfrekvensen. För en frisk person är svängningarna inom normala värden och den relativa avvikelsen är ungefär 10%. För patienterna med FAP påverkas framförallt variablerna kopplade till hjärtmuskeln förutom HR som man visste sedan tidigare.

    Koherensen mellan eko-variablerna och HR är låg i antingen VLF-, very low frequency, eller LF-, low frequency, området och hög i den andra. I HF-, high frequency, området är koherensen hög för alla variabler.

    Slutligen görs PCA på mätningarna från alla friska personer som ett dataset, på en av de friska personerna och på en av patienterna med FAP. Analysen visar att för friska personer är andningen den process som orsakar mest variation och alla eko-variabler har en korrelation till andningen. För en patient med FAP är andningen inte lika framträdande. En PCA av block ur datat vid olika tidpunkter i signalen visar dock att signalerna inte svänger multivariat på samma sätt genom hela tidsserien.

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    AmandaAlbano_MScthesis
  • 24.
    Alenaini, Wareed
    et al.
    Research Centre for Optimal Health, School of Life Sciences, College of Liberal Arts and Sciences, University of Westminster, London, UK.
    Parkinson, James R. C.
    Research Centre for Optimal Health, School of Life Sciences, College of Liberal Arts and Sciences, University of Westminster, London, UK.
    McCarthy, John P.
    School of Healthcare Practice, University of Bedfordshire, Luton, Bedfordshire, UK.
    Goldstone, Anthony P.
    PsychoNeuroEndocrinology Research Group, Neuro‐psychopharmacology Unit, Centre for Psychiatry, Division of Brain Sciences, Imperial College London–Hammersmith Hospital, London, UK.
    Wilman, Henry R.
    Research Centre for Optimal Health, School of Life Sciences, College of Liberal Arts and Sciences, University of Westminster, London, UK. Perspectum Diagnostics, Oxford, UK.
    Banerjee, Rajarshi
    Perspectum Diagnostics, Oxford, UK.
    Yaghootkar, Hanieh
    Luleå tekniska universitet, Institutionen för hälsovetenskap. Research Centre for Optimal Health, School of Life Sciences, College of Liberal Arts and Sciences, University of Westminster, London, UK. Genetics of Complex Traits, Medical School, University of Exeter–Royal Devon & Exeter Hospital, Exeter, UK.
    Bell, Jimmy D.
    Research Centre for Optimal Health, School of Life Sciences, College of Liberal Arts and Sciences, University of Westminster, London, UK.
    Thomas, E. Louise
    Research Centre for Optimal Health, School of Life Sciences, College of Liberal Arts and Sciences, University of Westminster, London, UK.
    Ethnic Differences in Body Fat Deposition and Liver Fat Content in Two UK‐Based Cohorts2020Ingår i: Obesity, ISSN 1930-7381, E-ISSN 1930-739X, Vol. 28, nr 11, s. 2142-2152Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Objective

    Differences in the content and distribution of body fat and ectopic lipids may be responsible for ethnic variations in metabolic disease susceptibility. The aim of this study was to examine the ethnic distribution of body fat in two separate UK‐based populations.

    Methods

    Anthropometry and body composition were assessed in two separate UK cohorts: the Hammersmith cohort and the UK Biobank, both comprising individuals of South Asian descent (SA), individuals of Afro‐Caribbean descent (AC), and individuals of European descent (EUR). Regional adipose tissue stores and liver fat were measured by magnetic resonance techniques.

    Results

    The Hammersmith cohort (n = 747) had a mean (SD) age of 41.1 (14.5) years (EUR: 374 men, 240 women; SA: 68 men, 22 women; AC: 14 men, 29 women), and the UK Biobank (n = 9,533) had a mean (SD) age of 55.5 (7.5) years (EUR: 4,483 men, 4,873 women; SA: 80 men, 43 women, AC: 31 men, 25 women). Following adjustment for age and BMI, no significant differences in visceral adipose tissue or liver fat were observed between SA and EUR individuals in the either cohort.

    Conclusions

    Our data, consistent across two independent UK‐based cohorts, present a limited number of ethnic differences in the distribution of body fat depots associated with metabolic disease. These results suggest that the ethnic variation in susceptibility to features of the metabolic syndrome may not arise from differences in body fat.

  • 25.
    Almstedt, Lisa
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem.
    Wahlin, Maja
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem.
    Digital goniometer: Ett mätverktyg för att effektivisera rehabilitering efter böjsenskada2023Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Mellan år 2020 och år 2021 registrerades 381 operationer av böjsenskador i Sverige. Rehabiliteringsprocessen efter en böjsenskada är lång och kräver kontinuerlig uppföljning. Uppföljningen sker genom mätningar av böj- och sträckförmågan i de fingrar som patienten opererat. Mätningarna utförs i nuläget manuellt med goniometer, där vinklarna i fingrarnas leder mäts, en gång per vecka på en handkirurgisk mottagning. Handkirurgiska kliniken på Södersjukhuset i Stockholm efterfrågade ett digitalt mätverktyg som skulle göra det möjligt för patienten att på ett tillförlitligt sätt mäta vinklarna hemma i stället för på kliniken. Målet med projektet var således att skapa ett mätverktyg som mäter vinklarna med ett mätfel på högst 5 grader. Ett mätverktyg utvecklades som utför mätning av vinklar med hjälp av en bild användaren tagit. Mätverktyget är kompatibelt med Androidenheter och kan implementeras i en redan existerande Androidapplikation. Tester visade att mätverktyget har ett mätfel med ett medelvärde på 5 grader eller lägre för proximala interfalangealleden och distala interfalangealleden. Vidare var medelfelet 7,3 grader respektive 6,4 grader för metakarpofalangealleden vid böjt respektive sträckt finger, samt 10 grader för totalt aktivt rörelseomfång (total active motion).

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    Digital goniometer: Ett mätverktyg för att effektivisera rehabilitering efter böjsenskada
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  • 26.
    Alonso, Fabiola
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Deep brain stimulation: Patient-specific modelling, simulation and visualization of  DBS electric field2019Konferensbidrag (Övrig (populärvetenskap, debatt, mm))
  • 27.
    Alonso, Fabiola
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Modeling and simulation of DBS – comparison between leads and stimulation modes2014Konferensbidrag (Övrigt vetenskapligt)
  • 28.
    Alonso, Fabiola
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Models and Simulations of the Electric Field in Deep Brain Stimulation: Comparison of Lead Designs, Operating Modes and Tissue Conductivity2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Deep brain stimulation (DBS) is an established surgical therapy for movement disorders such as Parkinson’s disease (PD) and essential tremor (ET). A thin electrode is implanted in a predefined area of the brain with the use of stereotactic neurosurgery. In the last few years new DBS electrodes and systems have been developed with possibilities for using more parameters for control of the stimulation volume.

    In this thesis, simulations using the finite element method (FEM) have been developed and used for investigation of the electric field (EF) extension around different types of DBS lead designs (symmetric, steering) and stimulation modes (voltage, current). The electrode surrounding was represented either with a homogeneous model or a patient-specific model based on individual preoperative magnetic resonance imaging (MRI). The EF was visualized and compared for different lead designs and operating modes.

    In Paper I, the EF was quantitatively investigated around two lead designs (3389 and 6148) simulated to operate in voltage and current mode under acute and chronic time points following implantation.Simulations showed a major impact on the EF extension between postoperative time points which may explain the clinical decisions to change the stimulation amplitude weeks after implantation. In Paper II, the simulations were expanded to include two leads having steering function (6180, Surestim1) and patient-specific FEM simulations in the zona incerta. It was found that both the heterogeneity of the tissue and the operating mode, influence the EF distribution and that equivalent contact configurations of the leads result in similar EF. The steering mode presented larger volumes in current mode when using equivalent amplitudes. Simulations comparing DBS and intraoperative stimulation test using a microelectrode recording (MER) system (Paper III), showed that several parallel MER leads and the presence of the non-active DBS contacts influence the EF distribution and that the DBS EF volume can cover, but also extend to, other anatomical areas.

    Paper IV introduces a method for an objective exploitation of intraoperative stimulation test data in order to identify the optimal implant position in the thalamus of the chronic DBS lead. Patient-specific EF simulations were related to the anatomy with the help of brain atlases and the clinical effects which were quantified by accelerometers. The first results indicate that the good clinical effect in ET is due to several structures around the ventral intermediate nucleus of the thalamus.

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    Models and Simulations of the Electric Field in Deep Brain Stimulation: Comparison of Lead Designs, Operating Modes and Tissue Conductivity
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  • 29.
    Alonso, Fabiola
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Comparison of deep brain stimulation systems2014Ingår i: Poster Presentations, 2014, Vol. 29, s. 1173-1173, artikel-id Suppl 1Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Objective: To quantitatively compare the electric field generated by voltage and current controlled deep brain stimulation systems.

    Background: Traditionally deep brain stimulation (DBS) systems have used voltage control however more recently, current controlled systems have been approved to treat Parkinson's disease and related movement disorders. In the endeavor of understanding the behavior of DBS systems a common approach is the use of computer models suitable to simulate the electric field, current density and other related electric parameters.

    Methods: 2D finite element models based on commercially available DBS systems have been built for each system: I. Model 3389, Medtronic Inc., USA for voltage control; and II. Model 6142, St Jude Medical Inc. USA for current control. The brain tissue has been simplified to homogeneous and isotropic medium. The electric settings correspond to a monopolar configuration, using one of the four contacts available as the active electrode and the outer boundary of the tissue as the reference. Three simulations were performed to mimic different stages of the leads implantation: a) an original stage where the brain tissue is considered as pure gray matter, b) an acute stage that simulates the leakage of cerebral spinal fluid immediately after the electrodes' insertion; and c) a chronic stage mimicking fibrous tissue created around the electrodes some weeks after implantation. Both systems were submitted to the same conditions using as active electrode the third contact from the tip of the lead. The comparison is based on the maximal distance reached by the isopotential of 0.2 V/mm.

    Results: The simulations showed that voltage controlled stimulation systems are more susceptible to changes in the electrical conductivity of the medium i.e. change over time of the tissue around the electrode. This agrees with the adjustment of the stimulation amplitude often necessary a few weeks postoperatively. Current controlled stimulation in turn, presented a linear behavior of the distance reached at different stimulation amplitudes at all stages.

    Conclusions: Current controlled stimulation might be a good option due to its linear behavior over time, nevertheless more studies including a more realistic brain model, different designs of DBS electrodes and different electric parameter, are needed to encourage the use of this type of systems.

  • 30.
    Alonso, Fabiola
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska fakulteten.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska fakulteten.
    Latorre, Malcolm
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska fakulteten.
    Comparison of Three Deep Brain Stimulation Lead Designs under Voltage and Current Modes2015Ingår i: WORLD CONGRESS ON MEDICAL PHYSICS AND BIOMEDICAL ENGINEERING, 2015, VOLS 1 AND 2 / [ed] David A. Jaffray, Springer, 2015, Vol. 51, s. 1196-1199Konferensbidrag (Refereegranskat)
    Abstract [en]

    Since the introduction of deep brain stimulation (DBS) the technique has been dominated by Medtronic sys-tems. In recent years, new DBS systems have become available for patients, and some are in clinical trials. The present study aims to evaluate three DBS leads operated in either voltage or current mode. 3D finite element method (FEM) models were built in combination with a neuron model for this purpose. The axon diameter was set to D = 5 μm and simulations performed in both voltage (0.5-5 V) and current (0.5-5 mA) mode. The evaluation was achieved based on the distance from the lead for neural activation and the electric field (EF) extension at 0.1 V/mm. The results showed that the neural activation distance agrees well between the leads with an activation distance dif-ference less than 0.5 mm. The shape of the field at the 0.1 V/mm isopotential surface in 3D is mostly spherical in shape around the activated section of the steering lead.

  • 31.
    Alonso, Fabiola
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska fakulteten.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska fakulteten.
    Latorre, Malcolm
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska fakulteten.
    Neural Activation Compared to Electric Field Extension of Three DBS Lead Designs2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    SINCE the introduction of deep brain stimulation (DBS) about 20 years ago, the stimulation technique has been dominated by Medtronic DBS-system setup. In recent years, new DBS systems have become available, of which some are in clinical trials or available to patients [1]. In the present study three different lead designs are investigated via computer simulation:

    Medtronic 3389, St. Jude 6148 and Sapiens SureStim. The aim was to compare the neural activation distance and the electric field (EF) maximum spatial extension for each lead.

    A 3D finite element method model was built using COMSOL Multiphysics 4.4a (COMSOL AB, Stockholm, Sweden) to simulate the electric potential around the DBS lead. Brain tissue was modelled as a homogeneous volume of grey matter (electric conductivity of 0.09 S/m). The electrode-tissue interface was modelled with a 250μm thick peri-electrode space mimicking the fibrous tissue which covers the lead at the chronic stimulation stage (σ = 0.06S/m, equivalent to white matter electric conductivity). The stimulation amplitude was set to 1V in monopolar configuration using C1 electrode or equivalent in all cases. Each simulated electric potential distribution was exported to MatLab (The MathWorks, USA) and used as input to a cable neuron simulation.

    An axon cable model with 21 nodes based on the concept by Åström et al., [2] was set up in MatLab and combined with the exported field distributions. The model considered a 5 μm thick neuron, a pulse width of 60 μs and a drive potential ranging from 0.5 V to 5 V in 0.5 V steps.

    The SureStim lead results showed a shorter neural activation distance and EF extension. The distance to the isolevel of 0.2 V/mm is close to the neural activation distance at each stimulation amplitude, and we conclude that the electric field is a suitable predictor to visualize the stimulated regions.

  • 32.
    Alonso, Fabiola
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Zsigmond, Peter
    Region Östergötland, Centrum för kirurgi, ortopedi och cancervård, Kirurgiska kliniken US. Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för neuro- och inflammationsvetenskap. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Sinnescentrum, Neurokirurgiska kliniken US.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Avdelningen för medicinsk teknik. Linköpings universitet, Tekniska fakulteten.
    Influence of Virchow-Robin spaces in the Electric Field Distribution in Subthalamic Nucleus Deep Brain Stimulation2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Objectives: Previous investigations have shown the appearance of cysts i.e. Virchow-Robin spaces (VR) in the basal ganglia and their relationship with parkinsonian symptoms [1-3]. Simulations [4]using the finite element method (FEM) suggests that VR affects the electric field around deep brain stimulation (DBS) electrodes. The aim of the study was to evaluate how the electric field is modified by the presence of cysts in the STN. Methods: The effect of cysts on the electric field around the DBS lead placed in the STN was evaluated using FEM. 3D patient-specific brain models were built with COMSOL 5.2 (COMSOL AB, Sweden) and an in-house developed software [5] to convert a T2 weighted MRI of Parkinsonian patients (ethics approval no: 2012/434-3) into electrical conductivity matrix readable by FEM software. VR was classified as CSF [6]assigning a high electrical conductivity (2.0 S/m). The stimulation amplitudes were set to the clinically programmed values. Depending on the lead used, the stimulation was set to voltage control (3389) or current control (6180, ring mode). The coordinates corresponding to the lowest (first) electrode and the third higher up in the lead, taken from the postoperative CT electrode artefact, were used to localize the leads in the brain model [7]. The electric field was visualized with a 0.2V/mm isosurface. Results: Simulations showed that the electric field distribution is affected by the cysts. The higher conductivity at these regions in the vicinity of the electrode redistributes the electric field pushing it away from the cyst. The same effect occurs regardless of the operating mode or the lead design as long as the directional lead is configured in ring mode. Conclusions: The use of patient-specific models has shown the importance of considering nuances of the patients’ anatomy in the STN. This information can be used to determine the stimulation parameter and to support the analysis of side effects induced by the stimulation. The potential advantage of directional leads can also be assessed by including in the model patient-specific data.

  • 33.
    Alrifaiy, Ahmed
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    A gastight microfluidic system combined with optical tweezers and optical spectroscopy for electrophysiological investigations of single biological cells2011Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Stroke affects around 20 million people around the world every year. Clinically, stroke is a result of brain damage due to the shortage of oxygen delivered to the nerve cells. To minimize suffering and costs related to the disease, extensive research is performed on different levels. The focus of our research is to achieve fundamental understanding on how the lack of oxygen in brain tissue activates intrinsic biomolecular defense mechanisms that may reduce brain damage. More knowledge may hopefully lead to new therapeutic and preventive strategies on the molecular level for individuals in the risk zone for stroke or those who have just suffered a stroke. The area of study is based on the discovery of a hemoprotein called neuroglobin (Ngb), which is found in various regions in the brain, in the islets of Langerhans, and in the retina. Several studies have shown that Ngb seems to have a protective function against hypoxia-related damage. However, until now, it has not been understood how Ngb affects the nerve system and protects neurons from damage. The well-established patch-clamp technique is routinely used to measure and analyze the electrophysiological activity of individual biological cells. To perform accurate patchclamp experiments, it is important to create well-controlled physiological conditions, i.e. different oxygen levels and fast changes of nutrients and other biochemical substances. A promising approach is to apply lab-on-a-chip technologies combined with optical manipulation techniques. These give optimal control over fast changing environmental conditions and enable multiple readouts. The conventional open patch-clamp configuration cannot provide adequate control of the oxygen content. Therefore, it was substituted by a gas-tight multifunctional microfluidic system, a lab-on-a-chip, with an integrated patch-clamp micropipette. The system was combined with optical tweezers and optical spectroscopy. Laser tweezers were used to optically guide and steer single cells towards the fixed micropipette. Optical spectroscopy was used to investigate the biochemical composition of the sample. The designed, closed lab-on-a-chip acted as a multifunctional system for simultaneous electrophysiological and spectroscopic experiments with good control over the oxygen content in the liquid perifusing the cells. The system was tested in a series of experiments: optically trapped human red blood cells were steered to the fixed patch-clamp pipette within the microfluidic system. The oxygen content within the microfluidic channels was measured to 1 % compared to the usual 4-7 %. The trapping dynamics were monitored in real-time while the spectroscopic measurements were performed simultaneously to acquire absorption spectra of the trapped cell under varying environments. To measure the effect of the optical tweezers on the sample, neurons from rats in a Petri dish were optically trapped and steered towards the patch-clamp micropipette where electrophysiological investigations were performed. The optical tweezers had no effect on the electrophysiological measurements. Similar investigations within a closed microfluidic system were initiated and showed promising results for further developments of a complete lab-on-a-chip multifunctional system for reliable patch-clamp measurements. The future aim is to perform complete protocols of patch-clamp electrophysiological investigations while simultaneously monitoring the biochemical composition of the sample by optical spectroscopy. The straightforwardness and stability of the microfluidic chip have shown excellent potential to enable high volume production of scalable microchips for various biomedical applications. The subsequent ambition is to use this system as a mini laboratory that has benefits in cell sorting, patch-clamp, and fertilization experiments where the gaseous and the biochemical content is of importance. The long-term goal is to study the response of individual neurons and defense mechanisms under hypoxic conditions that may establish new ways to understand cell behavior related to Ngb for various diseases such as stroke, Alzheimer’s and Parkinson’s.

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  • 34.
    Alrifaiy, Ahmed
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Lab on a chip for electrophysiological measurements with control of the oxygen content: optical manipulation and spectroscopic analysis of biological cells2013Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Stroke affects nearly 20 million people around the world every year. Clinically, stroke is a result of brain damage due to the shortage of oxygen delivered to the nerve cells. To minimize suffering and costs related to the disease, extensive research is performed on different levels. The focus of our research is to achieve fundamental understanding on how the lack of oxygen in brain tissue activates intrinsic biomolecular defense mechanisms that may reduce brain damage. More knowledge may hopefully lead to new therapeutic and preventive strategies on the molecular level for individuals in the risk zone for stroke or those who have just suffered a stroke.The area of study is based on the discovery of a hemoprotein called neuroglobin (Ngb), which is found in various regions in the brain, in the islets of Langerhans, and in the retina. Several studies have shown that Ngb seems to have a protective function against hypoxia-related damage. However, until now, it has not been understood how Ngb affects the nerve system and protects neurons from damage.The well-established patch-clamp technique is routinely used to measure and analyze the electrophysiological activity of individual biological cells. To perform accurate patchclamp experiments, it is important to create well-controlled physiological conditions, i.e. different oxygen levels and fast changes of nutrients and other biochemical substances. A promising approach is to apply lab on a chip technologies combined with optical manipulation techniques. These give optimal control over fast changing environmental conditions and enable multiple readouts.The conventional open patch-clamp configuration cannot provide adequate control of the oxygen content. Therefore, the aim of the thesis was to design and test a multifunctional microfluidic system, lab on a chip (LOC), that can achieve normoxic, anoxic and hypoxic conditions. The conventional patch clamp configuration was substituted by a gas-tight LOC system with an integrated patch-clamp micropipette. The system was combined with optical tweezers, optical sensor and optical spectroscopy.Optical tweezers were used to trap and guide single cells through the LOC microchannels towards the fixed micropipette. Optical spectroscopy was essential to investigate the biochemical composition of the biological samples. The developed, gas-tight LOC acted as a multifunctional system for simultaneous electrophysiological and spectroscopic experiments with good control over the oxygen content in the liquid perifusing the cells. The system was tested in series of experiments: optically trapped cells (red blood cells from human and chicken and nerve cells) were steered to the fixed patch-clamp pipette within the LOC system. The oxygen content within the microfluidic channels was measured to ∼ 1% compared to the usual 4-7% found in open system. The trapping dynamics were monitored in real-time while the spectroscopic measurements were performed simultaneously to acquire absorption spectra of the trapped cell under varying environments. To measure the effect of the laser tweezers on the sample, neurons from rats in a Petri dish were optically trapped and steered towards the patch-clamp micropipette where electrophysiological investigations were performed. The optical tweezers had no effect on the electrophysiological measurements.The future aim is to perform complete protocols of patch-clamp electrophysiological investigations while simultaneously monitoring the biochemical composition of the sample by optical spectroscopy. The straightforwardness and stability of the microfluidic chip have shown excellent potential to be applied for various biomedical applications. The subsequent ambition is to use this system as a mini laboratory that has benefits in cell sorting, patch-clamp and fertilization experiments where the gaseous and the biochemical content is of importance.The long-term goal is to study the response of individual neurons and defense mechanisms under hypoxic conditions that may establish new ways to understand cell behavior related to Ngb for various diseases such as stroke, Alzheimer’s and Parkinson’s.

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  • 35.
    Alrifaiy, Ahmed
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Bitaraf, Nazanin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Druzin, Michael
    Umeå universitet, Integrativ Medicinsk Biologi, Fysiologi.
    Lindahl, Olof
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ramser, Kerstin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Hypoxia on a chip - a novel approach for patch-clamp studies in a microfluidic system with full oxygen control2012Ingår i: World Congress on Medical Physics and Biomedical Engineering, May 26-31, 2012, Beijing, China / [ed] Mian Long, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2012, s. 313-316Konferensbidrag (Refereegranskat)
    Abstract [en]

    A new approach to perform patch-clamp experiments on living cells under controlled anoxic and normoxic conditions was developed and tested. To provide an optimal control over the oxygen content and the biochemical environment a patch-clamp recording micropipette was integrated within an oxygen tight poly-methyl methacrylate (PMMA) based microchip. The oxygen content within the microfluidic chamber surrounding patch-clamp micropipette was maintained at 0.5-1.5 % by a continuous flow of artificial extracellular solution purged with nitrogen. The nerve and glial cells acutely obtained from the male rat brain were trapped by the optical tweezers and steered towards the patch-clamp micropipette through the channels of the microchip in order to achieve a close contact between the pipette and the cellular membrane. The patch-clamp recordings revealed that optical tweezers did not affect the electrophysiological properties of the tested cells suggesting that optical trapping is a safe and non-traumatizing method to manipulate living cells in the microfluidic system. Thus, our approach of combining optical tweezers and a gas-tight microfluidic chamber may be applied in various electrophysiological investigations of single cells were optimal control of the experimental conditions and the sample in a closed environment are necessary.

  • 36.
    Alrifaiy, Ahmed
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Bitaraf, Nazanin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Druzin, Michael
    Umeå universitet, Integrativ Medicinsk Biologi, Fysiologi.
    Lindahl, Olof
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ramser, Kerstin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Patch-clamp measurements on a chip with full control over the oxygen content2012Ingår i: Journal of Biochips & Tissue Chips, ISSN 2153-0777, Vol. 2, nr 1, s. 1-5Artikel i tidskrift (Refereegranskat)
  • 37.
    Alrifaiy, Ahmed
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Bitaraf, Nazanin
    Lindahl, Olof
    Ramser, Kerstin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Development of microfluidic system and optical tweezers for electrophysiological investigations of an individual cell2010Ingår i: Optical Trapping and Optical Micromanipulation VII: 1 - 5 August 2010, San Diego, California, United States ; [part of SPIE optics + photonics] / [ed] Kishan Dholakia; Gabriel C. Spalding, Bellingham, Wash: SPIE - International Society for Optical Engineering, 2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present a new approach of combining Lab-on-a-chip technologies with optical manipulation technique for accurate investigations in the field of cell biology. A general concept was to develop and combine different methods to perform advanced electrophysiological investigations of an individual living cell under optimal control of the surrounding environment. The conventional patch clamp technique was customized by modifying the open system with a gas-tight multifunctional microfluidics system and optical trapping technique (optical tweezers).The system offers possibilities to measure the electrical signaling and activity of the neuron under optimum conditions of hypoxia and anoxia while the oxygenation state is controlled optically by means of a spectroscopic technique. A cellbased microfluidics system with an integrated patch clamp pipette was developed successfully. Selectively, an individual neuron is manipulated within the microchannels of the microfluidic system under a sufficient control of the environment. Experiments were performed to manipulate single yeast cell and red blood cell (RBC) optically through the microfluidics system toward an integrated patch clamp pipette. An absorption spectrum of a single RCB was recorded which showed that laser light did not impinge on the spectroscopic spectrum of light. This is promising for further development of a complete lab-on-a-chip system for patch clamp measurements.

  • 38.
    Alrifaiy, Ahmed
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Bitaraf, Nazanin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Lindahl, Olof
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ramser, Kerstin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ett mikroflödessystem för multipla undersökningar av enstaka biologiska celler under hypoxiska förhållanden2011Konferensbidrag (Refereegranskat)
    Abstract [sv]

    Introduktion: Syftet med studien är att studera enstaka nervcellers respons vid syrebrist i ett mikroflödessystem för att förstå nervcellens respons vid stroke. Målet med studien var att utveckla ett slutet mikroflödessystem som ger optimal kontroll av den omgivande miljön och samtidigt möjliggöra elektrofysiologiska undersökningar under kontrollerade syreförhållande. Material och metoder: Mikroflödescellen utvecklades för ett inverterat mikroskop, utrustad med en optisk pincett och optisk spektroskopi samt patch-clamp för elektrofysiologiska studier på en enstaka nervcell. Istället för att föra en pipett mot en cell i ett öppet system fångades en enskild cell optiskt i ett slutet mikroflödessystem och fördes mot en fixerad patch-clamp mikropipett. Cellen utsattes för olika syrehalter och övervakades av ett UV-Vis spektroskop medan cellens elektrofysiologiska aktivitet registreras med patch-clamp. Det slutna mikroflödessystemet med integrerad mikropipett, kopplades till ett pumpsystem för införandet av celler och buffert med olika kemiska egenskaper och syrehalter. I ett inverterat mikroskop integrerades optisk pincett, UV-Vis spektrometer och patch-clamp. Resultat och diskussion: För att pröva konceptet fångades och fördes en röd blodcell optiskt mot mikropipetten som befann sig på en fast position i mikroflödescellen. Cellens syrebindningstillstånd varierades genom att tillsätta syrefri eller syresatt buffert och registrerades med UV-Vis spektrometern. I ett vidare experiment manipulerades en nervcell optiskt i ett öppet system mot patch-clamp pipetten och elektrofysiologiska mätningar utfördes. Vi kunde verifiera att den optiska pincetten inte påverkade den elektrofysiologiska mätningen. För närvarandet utförs elektrofysiologiska mätningar i det slutna mikroflödessystemet för att se hur nervcellerna reagerar under varierande syrehalt. Genom mätningarna hoppas vi att få mer kunskap om försvarsmekanismerna som igångsätts av neuroner under syrefattiga förhållanden.

  • 39. Alrifaiy, Ahmed
    et al.
    Lindahl, Olof
    Ramser, Kerstin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ett mikroflödessystem med optisk pincett och UV- vis för studier på enskilda biologiska celler2010Konferensbidrag (Övrigt vetenskapligt)
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  • 40.
    Alrifaiy, Ahmed
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Lindahl, Olof
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ramser, Kerstin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Patch-clamp electrophysiological measurements on single cells under hypoxic conditions in microfluidic systems2012Konferensbidrag (Refereegranskat)
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  • 41.
    Alrifaiy, Ahmed
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Lindahl, Olof
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ramser, Kerstin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Polymer-based microfluidic devices for pharmacy, biology and tissue engineering2012Ingår i: Polymers, E-ISSN 2073-4360, Vol. 4, nr 3, s. 1349-1398Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper reviews microfluidic technologies with emphasis on applications in the fields of pharmacy, biology, and tissue engineering. Design and fabrication of microfluidic systems are discussed with respect to specific biological concerns, such as biocompatibility and cell viability. Recent applications and developments on genetic analysis, cell culture, cell manipulation, biosensors, pathogen detection systems, diagnostic devices, high-throughput screening and biomaterial synthesis for tissue engineering are presented. The pros and cons of materials like polydimethylsiloxane (PDMS), polymethylmethacrylate (PMMA), polystyrene (PS), polycarbonate (PC), cyclic olefin copolymer (COC), glass, and silicon are discussed in terms of biocompatibility and fabrication aspects. Microfluidic devices are widely used in life sciences. Here, commercialization and research trends of microfluidics as new, easy to use, and cost-effective measurement tools at the cell/tissue level are critically reviewed.

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  • 42.
    Alrifaiy, Ahmed
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Ramser, Kerstin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    How to integrate a micropipette into a closed microfluidic system: absorption spectra of an optically trapped erythrocyte2011Ingår i: Biomedical Optics Express, E-ISSN 2156-7085, Vol. 2, nr 8, s. 2299-2306Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present a new concept of integrating a micropipette within a closed microfluidic system equipped with optical tweezers and a UV-Vis spectrometer. A single red blood cell (RBC) was optically trapped and steered in three dimensions towards a micropipette that was integrated in the microfluidic system. Different oxygenation states of the RBC, triggered by altering the oxygen content in the microchannels through a pump system, were optically monitored by a UV-Vis spectrometer. The built setup is aimed to act as a multifunctional system where the biochemical content and the electrophysiological reaction of a single cell can be monitored simultaneously. The system can be used for other applications like single cell sorting, in vitro fertilization or electrophysiological experiments with precise environmental control of the gas-, and chemical content.

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  • 43.
    Alvarez, Victor
    et al.
    KTH.
    Halldin, Peter
    KTH.
    Kleiven, Svein
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik.
    The Influence of Neck Muscle Tonus and Posture on Brain Tissue Strain in Pedestrian Head Impacts2014Ingår i: SAE Technical Papers, ISSN 0148-7191, Vol. 58Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Pedestrians are one of the least protected groups in urban traffic and frequently suffer fatal head injuries. An important boundary condition for the head is the cervical spine, and it has previously been demonstrated that neck muscle activation is important for head kinematics during inertial loading. It has also been shown in a recent numerical study that a tensed neck musculature also has some influence on head kinematics during a pedestrian impact situation. The aim of this study was to analyze the influence on head kinematics and injury metrics during the isolated time of head impact by comparing a pedestrian with relaxed neck and a pedestrian with increased tonus. The human body Finite Element model THUMS Version 1.4 was connected to head and neck models developed at KTH and used in pedestrian-to-vehicle impact simulations with a generalized hood, so that the head would impact a surface with an identical impact response in all simulations. In order to isolate the influence of muscle tonus, the model was activated shortly before head impact so the head would have the same initial position prior to impact among different tonus. A symmetric and asymmetric muscle activation scheme that used high level of activation was used in order to create two extremes to investigate. It was found that for the muscle tones used in this study, the influence on the strain in the brain was very minor, in general about 1-14% change. A relatively large increase was observed in a secondary peak in maximum strains in only one of the simulated cases. 

  • 44.
    Ander, Simon
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem.
    Valo, Wille
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem.
    Utveckling av en mobilapplikation för rehabilitering av böjsenskador2023Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Böjsenor är senor i fingrarna som är kopplade till underarmens muskler. De läker långsamt efter en skada och kan därför gå av efter en reparation om patienten tränar för mycket eller för tungt. Vid för lite träning fastnar senan i omgivande vävnad och fingret blir stelt. Rehabiliteringen efter en böjsenskada pågår under minst tre månader efter operationen. Det kan därför bli svårt för patienter att upprätthålla motivationen och följa alla instruktioner korrekt under hela denna tid.  

    Syftet med projektet var att skapa en mobilapplikation som stödjer patienter i deras rehabilitering av en böjsenskada samt att implementera ett digitalt vinkelmätningsverktyg i applikationen. Applikationen utvecklades för både iOS- och Android-enheter med hjälp av deras officiella utvecklingsmiljöer, Android Studio och Xcode. Några funktioner som applikationen består av är en kalender med översikt av träningsplanen, möjligheten att utvärdera pass, möjligheten att skapa träningsprogram och exportera träningsdata. Applikationen innehåller även information om träningsinnehållet, kontaktinformation och allmänna råd till patienten.  

    Innan applikationen kan publiceras måste den testas på patienter för att få återkoppling om användarvänlighet och funktionalitet. De önskade funktionerna från uppdragsgivaren och målen uppnåddes med undantag av funktionen att lägga till möten som prioriterades bort. Det digitala vinkelmätningsverktyget implementerades för Android men inte för iOS. 

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  • 45. Andersson, Martin
    et al.
    Mattsson, Soren
    Johansson, Lennart
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Leide-Svegborn, Sigrid
    A biokinetic and dosimetric model for ionic indium in humans2017Ingår i: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 62, nr 16, s. 6397-6407Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper reviews biokinetic data for ionic indium, and proposes a biokinetic model for systemic indium in adult humans. The development of parameter values focuses on human data and indium in the form of ionic indium(III), as indium chloride and indium arsenide. The model presented for systemic indium is defined by five different pools: plasma, bone marrow, liver, kidneys and other soft tissues. The model is based on two subsystems: one corresponding to indium bound to transferrin and one where indium is transported back to the plasma, binds to red blood cell transferrin and is then excreted through the kidneys to the urinary bladder. Absorbed doses to several organs and the effective dose are calculated for In-111- and In-113m-ions. The proposed biokinetic model is compared with previously published biokinetic indium models published by the ICRP. The absorbed doses are calculated using the ICRP/ICRU adult reference phantoms and the effective dose is estimated according to ICRP Publication 103. The effective doses for In-111 and In-113m are 0.25 mSv MBq(-1) and 0.013 mSv MBq(-1) respectively. The updated biokinetic and dosimetric models presented in this paper take into account human data and new animal data, which represent more detailed and presumably more accurate dosimetric data than that underlying previous models for indium.

  • 46.
    Andersson, Matilda
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    Analysis of Changes in Running Technique Between a Shod and Barefoot Running Condition.2016Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Background: Lately, barefoot running has become popular and there is a debate on the pros and cons of barefoot running with regards to running injuries. Many factors are causing injuries and one of the factors discussed is the fact that we run in shoes. When we run in shoes the biomechanics of the running technique may and therefore be a possible cause to injury. Aim: The aim of the study was to assess how the foot strike pattern, angle of the knee and ankle joint at time of initial contact, as well as the step length changes between a shod and barefoot running condition in habitually shod runners when running in a pace equivalent to their running pace over ten kilometers. Method: Twenty-seven healthy runners (18 male, 9 female) were included in the study. The study took place at the fitness center of Halmstad University. Subjects ran on a treadmill, in an individual pace equivalent to their running pace over ten km, both in a shod and barefoot running condition. Two-dimensional analysis of the sagittal plane kinematics of the knee joint, ankle joint and foot position to horizontal, foot strike pattern and step length was done. Participants ran for ten minutes with shoes and for five minutes barefoot. Running technique was videotaped using an Iphone 6 camera and landmarks were marked with white tape to ease the analysis. Results: Changes in foot strike pattern was observed. When running barefoot 63% of the subjects adopted a non-heel strike pattern compared to 18.5% when shod (p=0.001). Knee flexion was increased at IC for the barefoot condition, with 164°±6 relative knee angle compared to 167°±6 when shod (p=0.001). Ankle angle at IC did not show a statistical significant difference between conditions (p=0.657). When barefoot the angle was 117°±8 compared to 115°±8 when shod. Foot angle to horizontal showed a flatter foot placement at IC with a less dorsiflexed foot for the barefoot condition (-4°±8) compared to shod (-12°±8), (p=0.001). Step length was decreased for the barefoot condition (0.82m ±0.15)   compared to shod (0.85m ±0.13), (p=0.008). Conclusion: Results are consistent with previous findings that barefoot running in some cases change the running technique with a flatter foot placement, an increased knee flexion at IC and a decreased step length. However, caution must be taken when habitually shod runners transition to barefoot running in regards to the biomechanical changes that may occur. To benefit from barefoot running a non-heel strike pattern is required. Further, the running technique may be the more important factor, regardless of wearing shoes or not.

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  • 47.
    Andersson, Simon
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Designing a fast and robust device for measuring and providing graphical visualization of the number of 60Co sources in a Leksell Gamma Knife®2020Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The Leksell Gamma Knife® (LGK) is a device for performing radiosurgery. The LGK contains approximately 200 radioactive sources whose beams intersect in a focal point in order to treat brain tumours. Quality assurance tools are used at Elekta to indirectly assess the number of sources in an LGK from the total amount of radiation. In order to increase patient safety, regulatory agencies have been asking for evidential proof of the number of sources in the LGK. This thesis' goal is to directly measure each source in the LGK and optimize the total detection time. To do this, a source detection system was developed with two parts, a radiation detection system and a moving gantry. Initial tests of the design were performed at Elekta and a final test was performed on an LGK at Karolinska Universitetssjukhuset. The results show that the proposed design has the possibility of detecting all sources in an LGK.

    Ladda ner fulltext (pdf)
    Simon_Andersson_Student_Thesis
  • 48.
    Angelopoulos, Angelos
    et al.
    -.
    Aslanides, E.
    -.
    Backenstoss, G.
    -.
    Bargassa, P.
    -.
    Behnke, O.
    -.
    Benelli, A.
    -.
    Bertin, V.
    -.
    Blanc, F.
    -.
    Bloch, P.
    -.
    Carlson, P.
    -.
    Danielsson, Mats
    KTH, Tidigare Institutioner (före 2005), Fysik.
    K0⇋ K̄0 transitions monitored by strong interactions: a new determination of the K L–K S mass difference2001Ingår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 503, nr 1, s. 49-57Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 49.
    Angland, Erik
    et al.
    Östergötlands Läns Landsting, Centrum för kirurgi, ortopedi och cancervård, Radiofysikavdelningen US.
    Karlsson, Henrik
    Östergötlands Läns Landsting, Centrum för kirurgi, ortopedi och cancervård, Radiofysikavdelningen US.
    Gustafsson, Agnetha
    Östergötlands Läns Landsting, Centrum för kirurgi, ortopedi och cancervård, Radiofysikavdelningen US.
    Pettersson, Håkan
    Östergötlands Läns Landsting, Centrum för kirurgi, ortopedi och cancervård, Radiofysikavdelningen US.
    Luftmätningar av  inhalerat 99mTc till BMA vid ventilationsundersökningar med Technegas.2006Konferensbidrag (Övrigt vetenskapligt)
  • 50.
    Antonsson, Jacob
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Motion Tracking Using a Permanent Magnet2013Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In this project the possibility of using a network of magnetometers sensing a permanent magnet for tracking has been investigated. Both the orientation and the position of the magnet have been considered. A dipole approximation of the magnetic field is used to develop two models. One of the models parametrizes the orientation with the magnetic moment vector, while the other parametrizes the orientation with a unit quaternion. An extended Kalman filter have been used to estimate position and orientation.

    Several calibration algorithms have been developed to calibrate for sensor errors, differences in sensor coordinate frame orientations and also for the estimation of the magnetic moment norm of a permanent magnet. The models have been tested using an optical reference system for position and orientation estimation. Initial results are ambiguous and further testing is necessary. One conclusion is that the model using the magnetic moment vector as orientation parametrization is less sensitive to the accuracy of the initial guesses of the filter recursions and also less sensitive to possible model errors.

    A mathematical result of the possibility of using a non stationary sensor network to track the magnet is also given.

    Ladda ner fulltext (pdf)
    fulltext
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