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<p>This thesis addresses the biomechanics of the human middle ear, that part of the auditory system which converts sound pressure waves in air to fluid pressure waves in the cochlea. The middle ear's mechanism is analysed in four papers, three main and one supporting; in the main papers the middle ear is treated as a multi-particle, multi-rigid body ensemble possessing a variable number of degrees of freedom depending upon the case being investigated.</p><p>It is confirmed, using the standard representation of a single fused incudo-malleal block, that the middle ear's motion is linear, but when this fused block restriction is lifted nonlinearity is present which significantly affects the mechanism's behaviour. In view of the linearity of the chain under the fused block conditions, the explanatory veracity of the conventionally accepted `fixed axis hypothesis' of ossicular motion is examined and found to be wanting as a realistic description of the chain's physical movement.</p><p>The nonlinear behaviour of the ossicular chain centres around the action of the incudo-malleal joint. This joint is shown to have preferential planes of operation, principally the pitch or longitudinal plane and in general to act as an efficient energy dissipator at high driving pressures and low frequencies. Providing the pressure is high enough, it is shown this energy dissipator effect eventually becomes independent of frequency.</p><p>The supporting paper discusses the dynamics of the imposition and removal of equation constraints justifying methods used to investigate the functioning of the incudo-malleal joint.</p>

Excel is a great tool, however it has its flaws. Files quickly become slow as they increase in size, and Excel has no built-in feature to easily search through several documents for a specific word, phrase or value. This can be resolved through a LIMS, a Laboratory Information Management System, which is a database solution that can be used to store and trace laboratory data and information. Our task was to evaluate what system requirements the company Olink Proteomics AB has for a LIMS. By interviewing several departments at Olink, we gained information about what each group wanted from such a system and condensed it into a needs assessment. The interviews showed that traceability was needed for every single department, as well as having easy features for adding data into the system. We were also tasked by Olink to research which Swedish laws apply to old patient data, as the company wants to reuse the data for R&amp;D. Our conclusions are that if data is made fully anonymous, there are no issues in using it for R&amp;D. However, this can be difficult as many criteria have to be fulfilled in order for the data to become fully anonymous.

<p>The pumping performance of the heart is affected by the mechanical properties of the muscle fibre part of the cardiac wall, the myocardium. The myocardium has a complex structure, where muscle fibres have different orientations at different locations, and during the cardiac cycle, the myocardium undergoes large elastic deformations. Hence, myocardial strain pattern is complex. In this thesis work, a computation method for myocardial strain and a detailed map of myocardial transmural strain during the cardiac cycle are found by the use of surgically implanted metallic markers and beads. The strain is characterized in a local cardiac coordinate system. Thereafter, non-invasive phase contrast magnetic resonance imaging (PC-MRI) is used to compare strain at different myocardial regions. The difference in resolution between marker data and PC-MRI data is elucidated and some of the problems associated with the low resolution of PC-MRI are given.</p>

<p>The county of Dalarna is at present carrying through a process of digitalization where traditional x-ray film is being replaced with digital detectors. Earlier used methods for dose optimization turned out not being sufficient. This report presents a method to harmonize dose levels between x- ray sites equipped with Fujifilm imaging plate systems. An exposure index, S, related to the dose level of the examination is computed to every x-ray image. S turned out to be inversely proportional to the detector dose used at the examination. Detector dose is also the one simulated factor that doubtlessly affects S the most.There are however a lot of parameters, e.g difference between patients, that are not easily simulated even though they still have considerable affect. The method for harmonizing dose levels between x-ray sites are based on statistics of collected S-values for a kind of examination. The average of the collected S-values levels variations and is a more solid measure of the dose level for the examination. By means of this method the dose level of frontal images of the lungs at a site have been reduced by 30 per cent without endanger the diagnostic security.</p>

<p>The county hospital of Dalarna has for the last couple of years carried through a process of digitalization. The result is that within the county it exists image plate systems from two different manufacturers. In an attempt to create a tool for dose optimization and dose surveillance the county of Dalarna would like to investigate if the exposure index from Agfa and Fuji is suitable as a dose indicator. An investigation of the exposure index, S, from Fuji has already been done. This thesis has been continuing the investigation by evaluating the stability of the exposure index, lgM, from Agfa. Simultaneously an observation if there is a simple relation between the exposure indicators from Agfa and Fuji has been performed. The result showed that the average of lgM, for a set of images from the same type of examination, is appropriate as a dose indicator to the image plate for that specific examination type and X-ray equipment. The usefulness is linked to the same tube voltage and Speed Class for a specific examination, and is to a certain degree restricted by the collimating. There is a relation between the exposure index from Agfa and Fuji, and there is in a simple way possible to transform S-values to lgM-values for comparison. The relation turned out to be examination specific.</p>

This thesis addresses the biomechanics of the human middle ear, that part of the auditory system which converts sound pressure waves in air to fluid pressure waves in the cochlea. The middle ear's mechanism is analysed in four papers, three main and one supporting; in the main papers the middle ear is treated as a multi-particle, multi-rigid body ensemble possessing a variable number of degrees of freedom depending upon the case being investigated. It is confirmed, using the standard representation of a single fused incudo-malleal block, that the middle ear's motion is linear, but when this fused block restriction is lifted nonlinearity is present which significantly affects the mechanism's behaviour. In view of the linearity of the chain under the fused block conditions, the explanatory veracity of the conventionally accepted `fixed axis hypothesis' of ossicular motion is examined and found to be wanting as a realistic description of the chain's physical movement. The nonlinear behaviour of the ossicular chain centres around the action of the incudo-malleal joint. This joint is shown to have preferential planes of operation, principally the pitch or longitudinal plane and in general to act as an efficient energy dissipator at high driving pressures and low frequencies. Providing the pressure is high enough, it is shown this energy dissipator effect eventually becomes independent of frequency. The supporting paper discusses the dynamics of the imposition and removal of equation constraints justifying methods used to investigate the functioning of the incudo-malleal joint.

The county of Dalarna is at present carrying through a process of digitalization where traditional x-ray film is being replaced with digital detectors. Earlier used methods for dose optimization turned out not being sufficient. This report presents a method to harmonize dose levels between x- ray sites equipped with Fujifilm imaging plate systems. An exposure index, S, related to the dose level of the examination is computed to every x-ray image. S turned out to be inversely proportional to the detector dose used at the examination. Detector dose is also the one simulated factor that doubtlessly affects S the most.There are however a lot of parameters, e.g difference between patients, that are not easily simulated even though they still have considerable affect. The method for harmonizing dose levels between x-ray sites are based on statistics of collected S-values for a kind of examination. The average of the collected S-values levels variations and is a more solid measure of the dose level for the examination. By means of this method the dose level of frontal images of the lungs at a site have been reduced by 30 per cent without endanger the diagnostic security.

The pumping performance of the heart is affected by the mechanical properties of the muscle fibre part of the cardiac wall, the myocardium. The myocardium has a complex structure, where muscle fibres have different orientations at different locations, and during the cardiac cycle, the myocardium undergoes large elastic deformations. Hence, myocardial strain pattern is complex. In this thesis work, a computation method for myocardial strain and a detailed map of myocardial transmural strain during the cardiac cycle are found by the use of surgically implanted metallic markers and beads. The strain is characterized in a local cardiac coordinate system. Thereafter, non-invasive phase contrast magnetic resonance imaging (PC-MRI) is used to compare strain at different myocardial regions. The difference in resolution between marker data and PC-MRI data is elucidated and some of the problems associated with the low resolution of PC-MRI are given.