There are several ways in which a disability can occur. Strokes are a leading cause, affecting older people in particular, with an estimated annual incidence rate of 180, 125, 200, and 280 per 100,000 citizens in the USA, Europe, England, and Scotland, respectively. Muscle strengthening through resistance training has been reported to have a positive effect on the recovery of normal physiological functions after the occurrence of a neurological or traumatic injury. A number of studies have shown that resistance training results in improved mobility, a reduction in pain, and improved stability. Several rehabilitation devices have been developed and introduced for use in the healthcare sector, but a new generation of intelligent therapy-assisted machines is needed if there is to be a significant impact on the numbers of patients that can be treated under current staffing level. In this project, the design and performance of multi-degree-of-freedom smart balland-socket dampers and their application to fully-controllable rehabilitation training systems were investigated. A key feature of these dampers is the use of magnetorheological (MR) fluids which can exhibit dramatic changes in their rheological properties, such as yield stress, when subjected to external magnetic fields. These fast and reversible fluid rheological changes would permit the smart damper to provide the required impedance at orthotic arm joints, which are aimed for upper-limb rehabilitations and in accord with the exercise specifications prescribed by the physiotherapist. An exemplar upper-limb orthotic arm incorporating smart ball-and-socket dampers at its joints was assessed using SolidWorks software and the results confirmed the response of the dampers to variable excitation inputs under an input simulating a wheelchair driving motion. This study also enabled the estimation of the orthotic arm reach envelope, task performance and limitations in which important device design factors such as the angle of rotation of the smart dampers were taken into account. Although, three smart dampers with variable torque resistance capability are required at the shoulder, elbow and wrist joints of upper-limb rehabilitation orthoses, this project was focused on the development of a smart ball-and-socket damper aimed for the shoulder joint only. The target was to produce a compact smart electromagnetic damper that is capable to deliver the required torque resistance with the least power consumption. The efficient excitation of MR fluids requires a magnetic circuit, which consists of a source of magnetic flux and a path to deliver it to the fluid. Electromagnetic finite element analysis using Ansys software were carried out to achieve the optimum design of the damper’s electromagnetic circuit. The effects of the relative permeability of the damper’s materials on the generation of the magnetic field and its delivery to the MR fluid were examined. Other factors such as the coil shape, size, orientation and location in addition to the utilisation of non-magnetic materials in the electromagnetic circuit design were also investigated with the aim to optimise the performance of the smart damper. Furthermore, 3-D electromagnetic analyses were conducted, which confirmed the validity of the 2-D magnetic trials. Accordingly, the size of the MR fluid ball-and-socket damper was estimated with a ball diameter of 100 mm, which was found to produce a braking torque of about 50 N.m when the MR fluid is energised by about 1 Tesla. The performance of the ball-and-socket damper was estimated using theoretical, and numerical approaches. The theoretical model combines the viscous-friction and the controllable field-dependent characteristics of the MR fluid in which a Bingham plastic model was used to simulate the shear stress of the fluid under various input conditions. The numerical approach involved a special procedure to simulate the device performance using computational fluid dynamics techniques, which were performed using Ansys CFX code. Three commercial MR fluids were assessed and it was found that the simulated device torque compared well with the theoretical values. The mechanical design of the optimised ball-and-socket damper was accomplished using SolidWorks software when several important design and manufacturing factors were taken into account. These factors included the assembly of the ball and socket parts, the sealing of the MR fluid inside its designated gap, winding of the coil inside the socket part, maintaining a uniform MR fluid gap, and insertion of the nonmagnetic rings at their predesigned locations. Finally, a dedicated experimental rig was constructed which facilitated the assessment of the smart damper under both static and dynamic testing conditions. It was found that agreement between model predictions and experimental observations was excellent. Furthermore, this device performance was found to meet torque requirements expected in most upper-limb rehabilitation regimes.

Hokkaido University (北海道大学) / 博士 / 医学

Functional Magnetic Resonance Imaging, fMRI, can be used for analyzing brain activity in subjects performing language tasks. The purpose of this study was to develop aphasia-friendly information adjusted to aphasic subjects participating in fMRI studies. The objectives were to investigate if adjusted information was important for the ability to perform language tasks and if the information could be used for different types of aphasia. Sixteen aphasic subjects participated in the study, six of these underwent fMRI. The participants varied in grade and type of aphasia. They had Swedish as their native language and were aged between 26 and 89, mean 57. Information was developed in three versions. The participants performed word generation and sentence completion language tasks. Results showed that all the participants produced significantly more words (p < 0.05), and completed significantly more sentences (p < 0.001) in the final version. The fMRI results showed high intersession variability, therefore intra- or intersubject comparisons were difficult to make. It was found that increased amount of time to solve the task and removal of the control task together with aphasia-friendly, concrete information improved performance. This applies to all participants, irrespective of aphasia type.

Mit Hilfe eines kommerziellen, am Universitätsklinikum Leipzig vorhandenen Navigationssystems (Localite) ist es möglich, Interventionen in einer herkömmlichen MRTUmgebung unter Echtzeitnavigation durchzuführen. In der vorliegenden Arbeit werden die Genauigkeit, Benutzerfreundlichkeit sowie der Zeitaufwand für perkutane Punktionen mit diesem System untersucht. Zur Navigation wird das jeweilige Instrument optisch verfolgt. Die automatische Patientenregistrierung außerhalb des MR-Tunnels erfolgt über eine einmalige 3DLokalisation spezieller MR-Marker. 24 Operateure mit unterschiedlicher radiologischer Erfahrung führten insgesamt 240 unterschiedlich schwere Punktionen an einem selbst entwickelten Phantom durch. Nach diesen Versuchen füllten die Operateure einen Fragebogen zur Handhabbarkeit des Systems aus. Zudem wurden 24 klinische perkutane Interventionen in nicht atemverschieblichen Körperregionen ausgewertet. Für alle Biopsien wurden Zeiten für charakteristische Arbeitsschritte dokumentiert. Die Treffergenauigkeit war im Phantomexperiment für alle Gruppen relativ hoch (Fachärzte: 93%, Assistenzärzte: 88%, Studenten 81%; Cochran p=0,104). Die dazugehörigen durchschnittlichen Zeiten für einen Biopsiezyklus lagen, gemessen in Minuten, bei 4:13 (FÄ), 4:42 (AÄ) und 5:06 (MS) (P<0,001). Die subjektiven Bewertungen des Navigationssystems an Hand der Aussagen (Items) des Fragebogens zeigten keine Abhängigkeit vom Erfahrungsgrad des Operateurs. Die diagnostische Genauigkeit der klinischen Interventionen lag bei 92%. Die mittlere Interventionszeit betrug dabei 18 min. Das Navigationssystem wurde erfolgreich für Interventionen in verschiedenen Körperregionen eingesetzt. Die Genauigkeit und die benötigten Eingriffszeiten sind mit anderen in der Literatur beschriebenen MRT-geführten Interventionen vergleichbar. Auch unerfahrene Operateure konnten das Navigationssystem relativ schnell und sicher anwenden.

Denna avhandling tar upp filmmusiken i Fantastic Mr. Fox. Syftet är mer specifikt att ta reda på vad musiken har för funktion i filmen, hur man använder musiken för att hjälpa till att föra fram handlingen och varför använder man sig av både egen komponerad musik och redan befintlig musik. Urvalet av låtar är grundat på hur stor betydelse de har för samspelet mellan musik och bild. Metoden som är använd är ett närstuderande, eller snarare ett närlyssnande, av musiken i filmen med hjälp av teoretisk grund i tidigare forskning och litteratur. Texten behandlar dels de låtar som är specifikt komponerade för filmen och dels de som är tagna utifrån, det vill säga redan befintlig musik, som har använts i filmen. Genom en diskussion utrönas också det olika musikala beståndsdelarnas viktigare element där diskussionen utmynnar i en jämförelse mellan de två musikala huvudgrupperna, det vill säga de sammanställda (de redan befintliga) låtarna och de sammansatta (de speciellt komponerade) låtarna. Avhandlingen slutar med att diskutera olika metoder man kan använda sig av för att studerna musiken i Fantastic Mr. Fox och även att förklara resultaten i analysen mer djupgående.

The essay examines the marriage of Antoinette and Mr. Rochester in the novel Wide Sargasso Sea by Jean Rhys.With the use of postcoloial feminist theory and close reading the essay shows that Mr. Rochester dominates Antoinette leaving her oppressed and diminished.

Dynamic responses of the MR Elastomers and MR gel have been studied care- fully by various research groups. However, to understand completely the dynamic response of the material, it is important to have a clear understanding of quasi-static response of the material. Thus, for the current work, we have studied quasi-static response of the MR gel. For current setup, 27 samples were prepared using Septon, plasticizer and magnetic particles and were tested for 3 rounds over 3 different magnetic fields under plane strain compression. The results from plane strain compression show linear increase in the load taken with the increase in concentration of magnetic particles in absence of any magnetic field. The response characteristics under uniform magnetic field showed a huge leap in the load taken for particular deflection. To study the quasistatic respose, the material is assumed to behave like an isotropic hyperelastic response. Field dependent Neo-Hookean and field dependent Valanis Landel models have been fit to the data, and it was found that simple 1-term field dependent Valanis Landel model with power law coefficient as four agrees well with the shear modulus obtained from experiments. The shear modulus of MAP from the Valanis Landel and Neo Hookean model was assumed to be linearly dependent on the concentration of magnetic particles and magnetic field, and this matched the experimental data well.

Changes in the characteristics of the structure, such as damage, have not been considered in most of the active and semi-active control methods that have been used to control and optimize the response of civil engineering structures. In this dissertation, a direct adaptive control which can deal with the existence of measurement errors and changes in structural characteristics or load conditioning is used to control the performance of structures. A Simple Adaptive Control Method (SACM) is modified to control civil structures and improve their performance. The effectiveness of the SACM is verified by several numerical examples. The SACM is used to reduce the structural response such as drift and acceleration using active and semi-active devices, and its performance is compared with that of other control methods. Also, a probabilistic indirect adaptive control method is developed and its behavior is compared to the SACM using a simple numerical example. In addition to the simplicity of the SACM implementation, the results show that SACM is very effective to reduce the response of structures with linear and non-linear behavior in comparison with other control methods.

Hepatic steatosis is common in the general population and is present in 13.25% of donor organs. It can affect graft survival and recovery of the donor after partial hepatectomy. Liver biopsy is the standard method to measure the degree of hepatic steatosis, but it¡¦s also an invasive procedure and may have sampling error. Non-invasive tools, such as computed tomography and magnetic resonance image, are generally utilized and developed. This study was designed to build a standard model for the quantification of the fat content in a fat-water mixed phantom model. Pork fat and pure water were mixed in different ratios by volume (from 0% fraction of fat to 100% fat in steps of 5%), and then measured for fat content in different concentrations of fat-water mixed phantom by using (1) CT number (Hounsfield unit; HU), (2) Dixon method (in-phase & opposed-phase), and (3) 1H spectroscopy (SVS30 & SVS136, without water suppression). The CT number decreased with increasing fat concentration. The Hounsfield units of pure fat were about -122 HU. At Dixon method, the fat image intensity increased to its maximum when the fat concentration reached 25% and then decreased. Fat concentration higher than 25% and lower than 25% both had the same value of the fat image intensity. Combined with SVS30 water/fat peak height ratio, the fat concentration could be estimated. Furthermore, the fat image could be utilized to observe the topographic distribution of hepatic steatosis. Then a rat fatty liver model fed with a choline deficient and iron supplemented L-amino acid defined (CDAA) diet was established. Fatty liver grade was evaluated by radiological and biochemical assessments. CT and MRS technique displayed the highest fat contents the same with histological examination in CDAA diet rats at 6 weeks. The results showed that MRS was a suitable method for quantifying fat to water concentration. As a result of this study, model of measurement scale can be established to measure fat concentration both in phanatoms and animal. Further study in human fatty liver was expected.

Magnetic resonance imaging (MRI) is one of medical images used by doctors for diagnosing diseases. MRI shows higher quality in displaying soft tissues and tumors. Pharmacokinetic dynamic gadolinium-enhanced MR imaging and functional MR imaging (fMRI) were used in this dissertation. Dynamic MR images are obtained using fast spin-echo sequences at consecutive time after the injection of gadolinium-diethylene-triamine penta-acetic (Gd-DTPA) acid. A pharmacokinetic model analyzes time-signal intensity curves of suspected lesions. Functional MR imaging produces images of activated brain regions by detecting the indirect effects of neuronal activity on local blood volume, flow, and oxygen saturation. Thus it is a promising tool for further understanding the relationships between brain structure, function, and pathology. Because of patients' movement during imaging, serially acquired MR images do not correspond in the same pixel position. Therefore, matching corresponding points from MR images is one of fundamental tasks in this dissertation. Least-squares estimation is a standard method for parameter estimation. However, outliers (due to non-Gaussian noise, lesion evolution, motion-related artifacts, etc.) may exist and thus may cause the motion parameter estimation result to deteriorate. In this dissertation, we describe two robust estimation algorithms for the registration of serially acquired MR images. The first estimation algorithm is based on the Newton method and uses the Tukey's biweight objective function. The second estimation algorithm is based on the Levenberg-Marquardt technique and uses a skipped mean objective function. The robust M-estimators can suppress the effects of the outliers by scaling down their error magnitudes or completely rejecting outliers using a weighting function. Experimental results show the accuracy of the proposed robust estimation algorithms is within subpixel. MR imaging has been used to evaluate nasal papilloma. However, postoperative MR imaging of nasal papilloma becomes more complicated because repair with granulation and fibrosis occurs after surgery. Therefore, it is possible to misclassify recurrences as postoperative changes or to misclassify postoperative changes as recurrences. Recently, dynamic gadolinium-enhanced MR imaging with pharmacokinetic analysis has been successfully used to identify the post-treatment recurrence or postoperative changes in rectal and cervical carcinoma. Nasopharyngeal carcinoma (NPC) comprising malignant tumors is a disease more common in Asia than in other parts of the world. Hence, in this dissertation, we evaluate the feasibility of dynamic gadolinium-enhanced MR imaging with pharmacokinetic analysis in detecting NPC and distinguishing recurrent nasal papilloma from postoperative changes (fibrosis or granulation tissue). In this dissertation, a new approach to differentiate recurrent nasal papilloma from postoperative changes using pharmacokinetic dynamic gadolinium-enhanced MR imaging and robust motion correction is presented. First, a robust estimation technique is incorporated into nonlinear minimization method to robustly register dynamic gadolinium-enhanced MR images. Next, user roughly selects the region of interest (ROI) and an active contour technique is used to extract a more precise ROI. Then, the relative signal increase (RSI) is calculated. We use a three-parameter mathematical model for pharmacokinetic analysis. The pharmacokinetic parameters A (enhancement amplitude) and Tc (tissue distribution time) are calculated by a nonlinear least-squares fitting technique. The calculated A and Tc are used to characterize tissue. Pharmacokinetic analysis shows that recurrent nasal papilloma has faster tissue distribution time (Tc, 41 versus 88 seconds) and higher enhancement amplitude (A, 2.4 versus 1.2 arbitrary units) than do postoperative changes. A cut-off of 65 seconds for tissue distribution time and 1.6 units for enhancement amplitude yields an accuracy of 100% for differentiating recurrent nasal papilloma from postoperative changes. Though the above methods obtained good results, finding the region of interest (ROI) was done in a semi-automatic manner. For diagnosing NPC and improve the drawback, a system that automatically detects and labels NPC with dynamic gadolinium-enhanced MR imaging is presented. This system is a multistage process, involving motion correction, gadolinium-enhanced MR data quantitative evaluation, rough segmentation, and rough segmentation refinement. Three approaches, a relative signal increase method, a slope method and a relative signal change method, are proposed for the quantitative evaluation of gadolinium-enhanced MR data. After the quantitative evaluation, a rough NPC outline is determined. Morphological operations are applied to refine the rough segmentation into a final mask. The NPC detection results obtained using the proposed methods had a rating of 85% in match percent compared with these lesions identified by an experienced radiologist. However, the proposed methods can identify the NPC regions quickly and effectively. In this dissertation, the proposed methods provide significant improvement in correcting the motion-related artifacts and can enhance the detection of real brain activation and provide a fast, valuable diagnostic tool for detecting NPC and differentiating recurrent nasal papilloma from postoperative changes.