Les anévrismes intracrâniens présentent des risques importants en raison de leur taux de rupture élevé et des conséquences qui peuvent être fatales comme lors d’hémorragies méningées. Afin d’effectuer une recherche hémodynamique sur l’anévrisme intracrânien in vitro, un fantôme est indispensable. Jusqu’à présent, des fantômes rigides ou simplifiés sont utilisés dans littérature, peu d’entre eux sont suffisamment fidèle à la réalité. Le travail de cette thèse se concentre sur la méthodologie de fabrication des fantômes patient-spécifiques d’anévrismes intracrâniens ainsi que leur mise en œuvre pour différentes utilisations. Ces fantômes possèdent la forme anatomique de l’artère du patient et une paroi élastique. Ils sont fabriqués en appliquant une technique originale de prototypage rapide. Les fantômes sont vérifiés selon plusieurs aspects. Pour effectuer des recherches hémodynamiques sur les fantômes, un banc d’essai compatible avec différentes modalités d’imagerie a été conçu. L’angiographie par résonance magnétique 2D par contraste de phase a été utilisée pour étudier l’hémodynamique des fantômes. Le comportement dynamique de paroi, les trajectoires 3D du flux et son champ de vélocité sont analysés. L’application potentielle dans domaine clinique du fantôme patient-spécifique a été aussi testée dans cette thèse, des simulations d’intervention sur des anévrismes intracrâniens ont été effectuées sur le banc d’essai et les fantômes, les résultats de différentes méthodes ont été analysés et comparés. / Intracranial aneurysms are a hazard to human health because of their high rupture rate and fatal subsequence, such as subarachnoid hemorrhage. In order to carry out a hemodynamic research in vitro on the intracranial aneurysm, a phantom is indispensable. Until now, rigid or simplified phantoms are mainly used in the literature, few among them possess sufficient properties compared with reality. The work of this thesis focuses on the methodology of manufacturing patient-specific phantoms of intracranial aneurysms as well as their implementation for different uses. The phantoms have an anatomical shape of patient’s artery and an elastic wall. They are manufactured by applying an original rapid prototyping technique. The phantoms are examined and verified in different ways. In order to perform a hemodynamic research of the phantoms, a testing platform compatible with different imaging modalities has been designed and established. 2D phase-contrast magnetic resonance angiography was applied in the hemodynamic study of the phantoms. The dynamic behavior of the artery wall, the 3D path-line of flow and the velocity field of flow were analyzed. The potential application in the clinical domain of the patient-specific phantoms was also tested in this thesis, simulations of intervention on intracranial aneurysms were carried out with the testing platform and the phantoms, the results of different treatment strategies were analyzed and compared.

Previous research has found a diverging trend between utilising social media (web 2.0) and traditional news media (web 1.0) on citizens trust towards democracy and democratic processes. This essay aims to investigate if this trend holds true in a Swedish context during a non-election year, and in doing so hope to advance the understanding of said trend. Thus, the following essay will investigate the change in trust towards the representative bodies within Sweden, with regards to the effects of either using social media or traditional media online as a means to take part of the digital flow of information.                       This is done by utilizing the SOM-survey, which collects information regarding citizen’s attitudes and general opinions towards political, social and medial habits every year. The data from this survey is then transformed into various indexes, with regards to citizens use of either web 1.0 or web 2.0, and their trust towards political institutions, and tested in an MRA-analysis. The findings of this study confirm the diverging trend between using web 1.0 and web 2.0 on citizen’s political trust. However, the positive correlation between web 1.0 and trust loose its statistical significance when a higher level of education is a factor. That is to say, academics tend to be less affected by web 1.0 with regards to their trust in representative bodies within the democracy. However, on the other hand the opposite holds true for web 2.0, where an inclusion of a higher level of education strengthens a negative correlation.

Fluidized bed dryers are used in the pharmaceutical industry for the batch drying of pharmaceutical granulate. Maintaining optimal hydrodynamic conditions throughout the drying process is essential to product quality. Due to the complex interactions inherent in the fluidized bed drying process, mechanistic models capable of identifying these optimal modes of operation are either unavailable or limited in their capabilities. Therefore, empirical models based on experimentally generated data are relied upon to study these systems.<p> Principal Component Analysis (PCA) and Partial Least Squares (PLS) are multivariate statistical techniques that project data onto linear subspaces that are the most descriptive of variance in a dataset. By modeling data in terms of these subspaces, a more parsimonious representation of the system is possible. In this study, PCA and PLS are applied to data collected from a fluidized bed dryer containing pharmaceutical granulate. <p>System hydrodynamics were quantified in the models using high frequency pressure fluctuation measurements. These pressure fluctuations have previously been identified as a characteristic variable of hydrodynamics in fluidized bed systems. As such, contributions from the macroscale, mesoscale, and microscales of motion are encoded into the signals. A multiresolutional decomposition using a discrete wavelet transformation was used to resolve these signals into components more representative of these individual scales before modeling the data. <p>The combination of multiresolutional analysis with PCA and PLS was shown to be an effective approach for modeling the conditions in the fluidized bed dryer. In this study, datasets from both steady state and transient operation of the dryer were analyzed. The steady state dataset contained measurements made on a bed of dry granulate and the transient dataset consisted of measurements taken during the batch drying of granulate from approximately 33 wt.% moisture to 5 wt.%. Correlations involving several scales of motion were identified in both studies.<p> In the steady state study, deterministic behavior related to superficial velocity, pressure sensor position, and granulate particle size distribution was observed in PCA model parameters. It was determined that these properties could be characterized solely with the use of the high frequency pressure fluctuation data. Macroscopic hydrodynamic characteristics such as bubbling frequency and fluidization regime were identified in the low frequency components of the pressure signals and the particle scale interactions of the microscale were shown to be correlated to the highest frequency signal components. PLS models were able to characterize the effects of superficial velocity, pressure sensor position, and granulate particle size distribution in terms of the pressure signal components. Additionally, it was determined that statistical process control charts capable of monitoring the fluid bed hydrodynamics could be constructed using PCA<p>In the transient drying experiments, deterministic behaviors related to inlet air temperature, pressure sensor position, and initial bed mass were observed in PCA and PLS model parameters. The lowest frequency component of the pressure signal was found to be correlated to the overall temperature effects during the drying cycle. As in the steady state study, bubbling behavior was also observed in the low frequency components of the pressure signal. PLS was used to construct an inferential model of granulate moisture content. The model was found to be capable of predicting the moisture throughout the drying cycle. Preliminary statistical process control models were constructed to monitor the fluid bed hydrodynamics throughout the drying process. These models show promise but will require further investigation to better determine sensitivity to process upsets.<p> In addition to PCA and PLS analyses, Multiway Principal Component Analysis (MPCA) was used to model the drying process. Several key states related to the mass transfer of moisture and changes in temperature throughout the drying cycle were identified in the MPCA model parameters. It was determined that the mass transfer of moisture throughout the drying process affects all scales of motion and overshadows other hydrodynamic behaviors found in the pressure signals.

Fluidized bed dryers are used in the pharmaceutical industry for the batch drying of pharmaceutical granulate. Maintaining optimal hydrodynamic conditions throughout the drying process is essential to product quality. Due to the complex interactions inherent in the fluidized bed drying process, mechanistic models capable of identifying these optimal modes of operation are either unavailable or limited in their capabilities. Therefore, empirical models based on experimentally generated data are relied upon to study these systems.<p> Principal Component Analysis (PCA) and Partial Least Squares (PLS) are multivariate statistical techniques that project data onto linear subspaces that are the most descriptive of variance in a dataset. By modeling data in terms of these subspaces, a more parsimonious representation of the system is possible. In this study, PCA and PLS are applied to data collected from a fluidized bed dryer containing pharmaceutical granulate. <p>System hydrodynamics were quantified in the models using high frequency pressure fluctuation measurements. These pressure fluctuations have previously been identified as a characteristic variable of hydrodynamics in fluidized bed systems. As such, contributions from the macroscale, mesoscale, and microscales of motion are encoded into the signals. A multiresolutional decomposition using a discrete wavelet transformation was used to resolve these signals into components more representative of these individual scales before modeling the data. <p>The combination of multiresolutional analysis with PCA and PLS was shown to be an effective approach for modeling the conditions in the fluidized bed dryer. In this study, datasets from both steady state and transient operation of the dryer were analyzed. The steady state dataset contained measurements made on a bed of dry granulate and the transient dataset consisted of measurements taken during the batch drying of granulate from approximately 33 wt.% moisture to 5 wt.%. Correlations involving several scales of motion were identified in both studies.<p> In the steady state study, deterministic behavior related to superficial velocity, pressure sensor position, and granulate particle size distribution was observed in PCA model parameters. It was determined that these properties could be characterized solely with the use of the high frequency pressure fluctuation data. Macroscopic hydrodynamic characteristics such as bubbling frequency and fluidization regime were identified in the low frequency components of the pressure signals and the particle scale interactions of the microscale were shown to be correlated to the highest frequency signal components. PLS models were able to characterize the effects of superficial velocity, pressure sensor position, and granulate particle size distribution in terms of the pressure signal components. Additionally, it was determined that statistical process control charts capable of monitoring the fluid bed hydrodynamics could be constructed using PCA<p>In the transient drying experiments, deterministic behaviors related to inlet air temperature, pressure sensor position, and initial bed mass were observed in PCA and PLS model parameters. The lowest frequency component of the pressure signal was found to be correlated to the overall temperature effects during the drying cycle. As in the steady state study, bubbling behavior was also observed in the low frequency components of the pressure signal. PLS was used to construct an inferential model of granulate moisture content. The model was found to be capable of predicting the moisture throughout the drying cycle. Preliminary statistical process control models were constructed to monitor the fluid bed hydrodynamics throughout the drying process. These models show promise but will require further investigation to better determine sensitivity to process upsets.<p> In addition to PCA and PLS analyses, Multiway Principal Component Analysis (MPCA) was used to model the drying process. Several key states related to the mass transfer of moisture and changes in temperature throughout the drying cycle were identified in the MPCA model parameters. It was determined that the mass transfer of moisture throughout the drying process affects all scales of motion and overshadows other hydrodynamic behaviors found in the pressure signals.

<p>Mice have become the preferred model system for studying brain function and disease. With the powerful genetic tools available, mouse models can be created to study the underlying molecular basis of neurobiology in vivo. Just as magnetic resonance imaging is the dominant tool for evaluating the human brain, high-resolution MRI--magnetic resonance microscopy (MRM)--is a useful tool for studying the brain of mouse models. However, the need for high spatial resolution limits the signal-to-noise ratio (SNR) of the MRM images. To address this problem, T1-shortening contrast agents can be used, which not only improve the tissue contrast-to-noise ratio (CNR) but also increase SNR by allowing the MR signal to recover faster between pulses. By "actively staining" the tissue with these T1-shortening agents, MRM can be performed with higher resolution, greater contrast, and shorter scan times. In this work, active staining with T1-shortening agents was used to enhance three types of in vivo mouse brain MRM: (1) angiographic imaging of the neurovasculature, (2) anatomical imaging of the brain parenchyma, and (3) functional imaging of neuronal activity.</p> <p></p> <p>For magnetic resonance angiography (MRA) of the mouse, typical contrast agents are not useful because they are quickly cleared by the body and/or extravasate from the blood pool before a high-resolution image can be acquired. To address these limitations, a novel contrast agent--SC-Gd liposomes--has been developed, which is cleared slowly by the body and is too large to extravasate from the blood pool. In this work, MRA protocols were optimized for both the standard technique (time-of-flight contrast) and SC-Gd liposomes. When the blood was stained with SC-Gd liposomes, small vessel CNR improved to 250% that of time-of-flight. The SC-Gd liposomes could also be used to reduce scan time by 75% while still improving CNR by 32%.</p> <p>For MRM of the mouse brain parenchyma, active staining has been used to make dramatic improvements in the imaging of ex vivo specimens. However for in vivo imaging, the blood-brain barrier (BBB) prevents T1-shortening agents from entering the brain parenchyma. In this work, a noninvasive technique was developed for BBB opening with microbubbles and ultrasound (BOMUS). Using BOMUS, the parenchyma of the brain could be actively stained with the T1-shortening contrast agent, Gd-DTPA, and MRM images could be acquired in vivo with unprecedented resolution (52 x 52 x 100 micrometers3) in less than 1 hour.</p> <p>Functional MRI (fMRI), which uses blood oxygen level dependant (BOLD) contrast to detect neuronal activity, has been a revolutionary technique for studying brain function in humans. However, in mice, BOLD contrast has been difficult to detect and thus routine fMRI in mice has not been feasible. An alternative approach for detecting neuronal activity uses manganese (Mn2+). Mn2+ is a T1-shortening agent that can enter depolarized neurons via calcium channels. Thus, Mn2+ is a functional contrast agent with affinity for active neurons. In this work, Mn2+ (administered with the BOMUS technique) was used to map the neuronal response to stimulation of the vibrissae. The resultant activation map showed close agreement to published maps of the posterior-lateral and anterior-medial barrel field of the primary sensory cortex.</p> <p>The use of T1-shortening agents to actively stain tissues of interest--blood, brain parenchyma, or active neurons--will facilitate the use of MRM for studying mouse models of brain development, function, and disease.</p> / Dissertation

No description available.

An image is a set of quantized intensity values that are sampled at a finite set of sample points on a two-dimensional plane. Images are crucial to many application areas, such as computer graphics and pattern recognition, because they discretely represent the information that the human eyes interpret. This thesis considers the use of triangular meshes for approximating intensity images. With the help of the wavelet-based analysis, triangular meshes can be efficiently constructed to approximate the image data. In this thesis, this study will focus on local image enhancement and mesh simplification operations, which try to minimize the total error of the reconstructed image as well as the number of triangles used to represent the image. The study will also present an optimal procedure for selecting triangle types used to represent the intensity image. Besides its applications to image and video compression, this triangular representation is potentially very useful for data storage and retrieval, and for processing such as image segmentation and object recognition. / Master of Science

In the chemistry branch of science is often a chromatograph usedto separate and purify substances in a solution. In achromatograph, different detectors are used to analyse the samplesconstituents. Some detectors destroy the sample during analysis.Because it is undesirable to destroy the entire flow of sample, asmall mass is transferred to a second flow by a flow splitter. Inthis report, four principles to divert a small mass from one flowto another are developed and evaluated. The basic principles todivert the flows is tested and principal mock-ups are designed andmanufactured. A brief survey of the market is conducted and aproblem related to flow spitting is investigated. The problem isthe influence on yield through a chromatograph due to flowretaining. Designing and testing of different retaining systems isalso included in this report. All four initial principles proved to be plausible splittingtechniques. However, only two principles appeared to be feasiblefor direct implementation in devices comparable withchromatographs. One of the less feasible principle is covered byseveral patents. The other is difficult to manufacture in order tomeet the strict requirements associated with e.g. chromatographs.The testing of different retaining systems showed that smallertube inner diameter and how the tube is winded can reduce theretaining system influence on the yield significantly. The splitting techniques in this report are all feasible splittingtechniques, and the report can be used as a solid foundation fordevelopment future laboratory instruments. / Inom kemin förekommer ofta kromatografer för att rena och separera kemiska substanser iett prov. De separerade substanserna kan detekteras och analyseras av olika detektorer, därvissa detektorer förstör provet i analysprocessen. Då det oftast är önskvärt att bevara såmycket som möjligt av ett prov, för vidare studier, avleds därför en liten mängd av deseparerade substanserna till detektorn då en förstörande detektor används. I denna studieutvecklades och undersöktes fyra principer för att avleda mycket små volymer från ett flödetill ett annat. Flödesdelning och sammanförning med de grundläggande flödesdelningsprincipernatestades, principiella modeller konstruerades och tillverkades. Enmarknadsundersökning samt en undersökning av ett flödesdelningsassocierat probleminkluderas också i rapporten. Problemet består i minskning av utbyte på grund avbandbreddning i flödesfördröjningssystem. Bandbreddning studerades således i olika formerav flödesfördröjningssystem. Alla fyra principer visade sig vara möjliga flödesdelningstekniker varav två av sådan karaktäratt de skulle kunna realiseras i ett instrument såsom en kromatograf. Av de två andra omfattasden ena av flertalet patent och den andra skulle vara tillverkningstekniks svår att förverkligamed vedertagna tillverkningstekniker. Tester på olika typer avflödesfördröjningssystemutformningar visade att slangdimension och hur slangen är lindadhar stor inverkan på bandbreddning. Det återstår en hel del konceptuell utveckling då principerna bara behandlats pågrundläggande nivå. Genom de principiella modellerna ges en bild av hur principerna skullekunna förverkligas, men vidare ställningstaganden måste tas till bland annat materialval samtmonitorering och anpassning av flöden. Rapporten ger en god grund för framtidaproduktutveckling.

Vatten är ett livsmedel som vi kommer i kontakt med dagligen. För att inte råka ut för sjuk-domar och infektioner renas dricksvattnet på vattenverken, främst för att reducera antalet patogener, d.v.s. sjukdomsframkallande mikroorganismer. Man brukar prata om tre grupper mikroorganismer i vattenrening; bakterier, virus och parasiter. Dessa grupper är vitt skilda i många avseenden och reduceras därför olika bra av olika reningssteg. Ju mer kunskap man kan få om reningsprocessen, desto bättre kan reningen optimeras. Därmed minimeras riskerna för konsumenterna att drabbas av infektioner. I det här arbetet används två modeller för att beskriva och utvärdera Borgs vattenverk som drivs av Norrköping Vatten AB. Modellen God desinfeksjonspraksis (GDP) är ett resultat av ett norskt projekt och baserar sig på formler och tabeller. Först avgörs råvattenkvaliteten genom att vattenverkets storlek och förekomst av mikroorganismer bedöms. Därefter görs diverse avdrag för förebyggande åtgärder, rening utöver desinfektion m.m. Slutligen bedöms desinfektionsgraden genom att det tillsatta klorets avklingning bestäms för beräkning av Ct-värdet; produkten av kontakttiden och koncentrationen. Genom att jämföra råvattenkvaliteten med avdragen och desinfektions-graden kan en bedömning göras om huruvida reningsprocessen är tillräcklig eller inte. I Mikrobiologisk riskanalys (MRA) bygger man upp en modell av sitt vattenverk i ett program och väljer patogenhalter för råvattnet. Efter det beräknar programmet renings-processens reduktion, riskerna för daglig respektive årlig sannolikhet för infektion samt DALYs, som gör att man kan jämföra risken för vattenburen smitta med exempelvis risken att förolyckas i trafiken. Det amerikanska naturvårdsverket och WHO har satt gränsen för den acceptabla årliga sannolikheten för infektion på grund av vattenrelaterad sjukdom till 1/10 000 invånare respektive 1 µDALYs. Fördelen med MRA är att när man väl byggt upp sitt vattenverk i programmet kan olika scenarion simuleras genom att patogenhalterna varieras. Tyvärr är det svårt att uppskatta patogenhalterna då de provtagningar som skulle behövas sällan är gjorda. Även litteraturvärden kan vara svårt att hitta, särskilt för virus som är så små att de är svåra att analysera. Resultatet av bägge modellerna visade på att Borgs vattenverks reduktionsförmåga är tillräcklig med avseende på bakterier, men inte för virus och parasiter. I MRA är det emellertid svårt att säga hur korrekt detta påstående är, då endast litteraturvärden kunnat användas för de två sistnämnda patogenerna. En del provtagningar har gjorts och då har inga parasiter kunnat påvisas i råvattnet, men för att inte underskatta riskerna användes litteratur-värdena ändå. GDP påvisade inga stora brister i reduceringen av virus och parasiter och i MRA låg resultatet i samma storleksordning som gränsen för DALYs. Eventuellt behöver alltså inga stora åtgärder vidtas för att minska de mikrobiologiska riskerna. De viktigaste stegen i reningsprocessen är långsamfiltrering, desinfektion med fritt klor och fällning och sedimentering med efterföljande filtrering. Infektionsrisken blir störst om fällningssteget slås ut. I samtliga simulerade scenarion låg infektionssannolikheten för bakterier fortfarande på en acceptabel nivå. Det värsta scenariot av de modellerade är om avloppsledningen från Skärblacka skulle börja läcka samtidigt som det regnar kraftigt. Det skulle leda till att förorening från betesmark spolas med ut i Motala Ström där råvattnet hämtas. Detta ger den högsta patogenhalten och därmed också den största infektionsrisken. / Water is one of the most basic things in life and is something we come in contact with on a daily basis. To prevent diseases and infections, the drinking water is purified, mainly in order to reduce the number of pathogens. The most important groups of microorganisms in water purification are bacteria, viruses, and parasites. These groups are very different in many respects and are therefore reduced most efficiently by different purification processes. If more knowledge is gained, the waterworks can optimize the purification process. This would lead to a minimization of the risk of getting infections caused by consuming the drinking water. In this paper two models are used to describe and evaluate Borg’s waterworks, run by Norrköping Vatten AB. Good Disinfection Practice (GDP) is the result of a Norwegian project and is based on formulas and tables. First, the raw water quality is determined by evaluating the presence of microorganisms and the number of people supplied. Then deductions are made due to security precautions and water treatment besides disinfection etc.  Finally the disinfection is determined by calculating the reduction of the added chlorine to gain the Ct-value, which is the product of the contact time and concentration. By comparison of the raw water, the deductions and the disinfection, the purification process can be evaluated as sufficient or not. In Quantitative Microbial Risk Assessment (QMRA) the purification process is modelled and concentrations of pathogens in the raw water are chosen. The program then calculates the reduction of the pathogens by the purification process. The result is also presented as probability of daily or annual infection and DALYs, which makes it possible to compare the risks of waterborne diseases with for example, the risk of traffic accidents. The US Environmental Protection Agency and the World Health Organization have determined the limit for the acceptable annual probability of infection due to water-related disease to 1/10,000 and 1 µDALYs. The advantage of the QMRA is that once you have modelled your purification process a variety of scenarios can be simulated. Unfortunately, it is difficult to estimate the concentrations of pathogens in the raw water and the acquired analysis are rarely made. Even literature values can be difficult to find, especially for viruses due to the difficulties in analysing them because of their small size. Both the models’ results showed that Borg’s waterworks reduction capacity is sufficient for bacteria, but not viruses and parasites. It is however difficult to say how accurate this conclusion is. In QMRA only literature values have been used as a basis to determine the risk for viruses and parasites. In fact, no parasites have been found when samples have been run on the raw water. But since an overestimation of the risk is to be preferred, literature values were used anyway. GDP showed only small shortcomings in the reduction of viruses and parasites and the values obtained from QMRA were in the same order of magnitude as the limit of DALYs. Therefore only small measures might be needed to lower the microbiological risks. The most important steps in the purification process are slow sand filtration, disinfection with free chlorine and precipitation and sedimentation with subsequent filtering. Elimination of the precipitating step results in the greatest risk of infection. In all the scenarios simulated the likelihood of infections caused by bacteria is still acceptable.  The worst-case scenario would be a sewage water leak during heavy raining. The rain would cause excrement from cattle to be washed into and contaminate the raw water in addition to the sewage contamination. This provides the highest concentration of pathogens in the raw water and therefore also the greatest risk of infection.

The Barrett (1972-1975) and Harcourt-Clark (1991-2001) New Democratic Party (NDP) governments attempted to redefine their relationship with the mining industry by changing the regulatory structures that governed mining in British Columbia. In both cases the mining industry publicly resisted these attempts, and was successful in having the reforms dismantled by subsequent free-enterprise oriented governments. These instances of conflict were centred on a foundational debate over government’s role in, and/or duty to, the mining industry. Intense industry-led resistance occurred when the traditional industry-government compact, which required government to serve as a promoter of the industry, and a liquidator of Crown owned mineral resources, was perceived to have been violated. The Barrett government more stringently asserted its ownership of public mineral resources through the enactment of a mineral royalty, and by assuming greater regulatory authority over mining operations. These actions instigated a substantial public relations campaign against the Barrett government over taxation laws. The Harcourt-Clark government pursued the development of strategic land-use plans and rejected the historic consensus that mining was innately the highest and best use of the land. This led to substantial anti-government rhetoric and an industry withdrawal from all public engagement and land-use planning processes. In both cases the mining industry was able to revive the traditional relationship when free-enterprise oriented governments replaced the NDP administrations. / Graduate / 2018-12-15