Quantitative cardiac magnetic resonance imaging (CMR) has gained traction within both the clinical and research field due to high prevalence of cardiovascular diseases. Cardiac magnetic resonance fingerprinting (cMRF) is a novel approach introduced to address the limitation associated with evaluation of multiparametric quantitative CMR. cMRF enables simultaneous and co-registered estimation of tissue relaxation times, T1 and T2, in a single acquisition, making it a more time-efficient approach to multiparametric quantitative CMR. Nevertheless, cMRF has not gained widespread adaption due to insufficient evidence regarding its performance in accurately quantifying tissue characteristics. This study aims to evaluate the accuracy and reproducibility of a single cMRF sequence described by Hamilton et. al. using self-constructed phantoms to validate the sequence performance for cardiac imaging. The objective was to construct in-vitro phantoms with physiological combinations of T1 and T2 markers. The phantoms were then imaged using gold standard and conventional mapping sequences to establish reference values for comparison. The measurements obtained from the two distinct cMRF reconstruction approaches were then compared to these reference values and to each other to evaluate the accuracy. The statistical assessments did not find a statistically significant difference between neither the cMRF sequence and conventional mapping techniques, nor cMRF and the gold-standard method, when compared in in-vitro phantoms with physiological combinations of T1 and T2. / Kvantitativ kardiovaskulär magnetresonans (CMR) har fått ökad uppmärksamhet inom både den kliniska- och forskningsfältet på grund av hög förekomst av hjärt- och kärlsjukdomar. För att åtgärda begränsningarna vid utvärdering av multiparametrisk kvantitativ CMR, introducerades cardiac magnetic resonance fingerprinting (cMRF) som en ny metod. cMRF möjliggör simultan och samregistrerad uppskattning av vävnadens relaxationstider, T1 och T2, i samma insamling, vilket gör det till en mer tidseffektiv metod för multiparametrisk kvantitativ CMR. Trots detta är kliniska implementeringen av cMRF inte utbredd på grund av otillräckligt bevis för dess utförande vid exakt kvantifiering av vävnadsegenskaper. Syftet med denna studie är att bedöma noggrannheten hos en cMRF-sekvens som utvecklats av Hamilton et al. genom att använda egentillverkade fantomer för att verifiera hur effektiv sekvensen är för avbildning av hjärtat. Målet är att konstruera in vitro-fantom med fysiologiska kombinationer av  T1- och T2-markörer. Dessa fantomer avbildades med hjälp av referensmetoder och konventionell karaktärisering för att etablera jämförelsevärden. Mätningarna som erhölls från de två distinkta cMRF-rekonstruktionsmetoderna jämfördes sedan statistiskt med jämförelsevärdena och med varandra för att utvärdera mätnoggrannheten. De statistiska bedömningarna kunde inte påvisa en skillnad mellan varken cMRF-sekvensen och konventionella metoder, eller referensmetod, vid jämförelse i in vitro-fantom med fysiologiska kombinationer av T1- och T2-värden.

Low-temperature magnetic force microscopy was used to study the phase diagram of a La1/3Pr1/3Ca1/3MnO3 thin film grown on a (110) NdGaO3 (NGO) substrate by pulsed laser deposition. Traditionally, one can observe the phase change at the nanoscale level as the sample is cooled from room temperature through the transition temperature to liquid nitrogen temperatures, but in this case a fixed voltage ranging from 0 V to 31 V was applied before each cooling cycle. From in and ex situ transport measurements, it is observed that the temperature of the peak of the transition increases with applied field; however, the MFM images show that the magnetic transition begins at a lower temperature with the same increase in field. Thus, this dissertation shows that a new voltage control exists for the phase transition in certain manganites. / text

Background Coarctation of the aorta (CoA) constitutes 5-8 % of all congenital heart disease (CHD) and is associated with long-term complications such as hypertension (HTN) and left ventricular hypertrophy (LVH). Factors associated with HTN, LVH, and diffuse myocardial fibrosis, are not yet fully explored in this population. Methods Papers I-III: The Swedish national register of congenital heart disease (SWEDCON) was used to identify adult patients with repaired CoA. Paper IV: Data on 2,424 adult patients with CHD was extracted from SWEDCON and compared to controls (n = 4,605) regarding height, weight and body mass index (BMI). Paper V: Adults with CoA (n = 21, age 28.5 (19.1-65.1) years, 33.3 % female) referred for CMR were investigated with T1 mapping to determine left ventricular extracellular volume fraction (ECV). Results Papers I-II: Out of 653 patients, 344 (52.7 %) had HTN. In a multivariable model, age (years) (OR 1.07, CI 1.05-1.10), sex (male) (OR 3.35, CI 1.98-5.68) and BMI (kg/m2) (OR 1.09, CI 1.03-1.16) were associated with having HTN, and so was systolic arm-leg blood pressure (BP) gradient where an association was found at the ranges (10, 20] mmHg (OR 3.58, CI 1.70-7.55) and > 20 mmHg (OR 11.38, CI 4.03-32.11), in comparison to the range [0, 10] mmHg. When investigating 243 patients with diagnosed HTN, 127 (52.3 %) had elevated BP (≥ 140/90 mmHg). Age (years) (OR 1.03, CI 1.01-1.06) was associated with elevated BP, and so was systolic arm-leg BP gradient in the ranges (10, 20] mmHg (OR 4.92, CI 1.76-13.79), and > 20 mmHg (OR 9.93, CI 2.99-33.02), in comparison to the reference interval [0, 10] mmHg. Patients with elevated BP had more classes of anti-hypertensive medication classes prescribed (1.9 vs 1.5, p = 0.003). Paper III: Out of 506 patients, 114 (22.5 %) were found to have LVH. Systolic BP (mmHg) (OR 1.02, CI 1.01-1.04), aortic valve disease, (OR 2.17, CI 1.33–3.53), age (years) (OR 1.03, CI 1.01–1.05), and HTN (OR 3.02, CI 1.81-5.02), were associated with LVH, while sex (female) (OR 0.41, CI 0.24-0.72) was negatively associated with LVH. Paper IV: There was no difference in height, weight, or BMI between patients with CoA (n = 414) and the reference population. Paper V: In the population of 21 patients, an increased left ventricular myocardial ECV was found in 6 cases (28.6 %). Of the patients with increased ECV, 5/6 (83.3 %) were female (p = 0.002). Patients with increased ECV did not otherwise differ from the rest of the study population. iv Conclusions In adults with repaired CoA, HTN and LVH were common, and many patients with HTN had elevated BP despite treatment. The potentially modifiable factors BMI and systolic arm-leg BP gradient were associated with HTN, and the gradient was also associated with elevated BP among patients with diagnosed HTN. The gradient’s significance remained even within what the current guidelines consider acceptable ranges. Potentially modifiable factors associated with LVH were systolic BP and aortic valve disease. We found no general difference in height, weight, or BMI between patients with CoA and the reference population. While LVH was more common among men, increased myocardial ECV was more common among women.

<p>The development of more advanced materials forms the basis of technological progress. One group of fascinating compounds with many potential applications in spintronic devices are the mixed-valence perovskite manganites. These have attracted considerable interest during the last decade through their very large magnetoresistance near the Curie Temperature. Although the properties of a material determinie any application, the development of reliable and flexible synthesis methods is crucial, as is the understanding of these methods. Knowledge of how different materials are formed is also of general importance in tailoring new materials. The aim of this project has therefore been not only to develop a new synthesis route, but also to understand the mechanisms involved.</p><p>This thesis describes the synthesis and characterization of a novel manganese alkoxide and its use in sol–gel processing of magnetoresistive perovskite manganites. In searching for a soluble manganese alkoxide for sol–gel processing, we found that the methoxy-ethoxide, [Mn₁₉O₁₂(moe)₁₄(moeH)₁₀]·moeH, has a high solubility in appropriate organic solvents. Being 1.65 nm across, it is one of the largest alkoxides reported; it is also of interest because of its (for oxo-alkoxides) rare planar structure. After mixing with La, Nd, Ca, Sr, and Ba methoxy-ethoxides, [Mn₁₉O₁₂(moe)₁₄(moeH)₁₀]·moeH was used in the first purely alkoxide based sol–gel processing of perovskites manganites. The phase evolution on heating xerogel powders to 1000°C was studied, and thin films were prepared by spin-coating.</p><p>It was found that the easily oxidised Mn-alkoxide facilitates the formation of high oxygen-excess modifications of the perovskites. The reactive precursor system yields fully hydrolysed gels almost without organic residues, but the gel absorbs CO₂ from the air, leading to carbonate formation. The carbonate decomposition is the limiting step in oxide formation. Transport measurements of La_0.67Ca_0.33MnO₃ films on LaAlO₃ substrate show that all-alkoxide sol–gel derived films can compete with PLD films in terms of quality of epitaxy and transport. The somewhat different behaviour of the sol–gel derived films compared to PLD films is attributed to differences in morphology and oxygen stoichiometry.</p>

The development of more advanced materials forms the basis of technological progress. One group of fascinating compounds with many potential applications in spintronic devices are the mixed-valence perovskite manganites. These have attracted considerable interest during the last decade through their very large magnetoresistance near the Curie Temperature. Although the properties of a material determinie any application, the development of reliable and flexible synthesis methods is crucial, as is the understanding of these methods. Knowledge of how different materials are formed is also of general importance in tailoring new materials. The aim of this project has therefore been not only to develop a new synthesis route, but also to understand the mechanisms involved. This thesis describes the synthesis and characterization of a novel manganese alkoxide and its use in sol–gel processing of magnetoresistive perovskite manganites. In searching for a soluble manganese alkoxide for sol–gel processing, we found that the methoxy-ethoxide, [Mn19O12(moe)14(moeH)10]·moeH, has a high solubility in appropriate organic solvents. Being 1.65 nm across, it is one of the largest alkoxides reported; it is also of interest because of its (for oxo-alkoxides) rare planar structure. After mixing with La, Nd, Ca, Sr, and Ba methoxy-ethoxides, [Mn19O12(moe)14(moeH)10]·moeH was used in the first purely alkoxide based sol–gel processing of perovskites manganites. The phase evolution on heating xerogel powders to 1000°C was studied, and thin films were prepared by spin-coating. It was found that the easily oxidised Mn-alkoxide facilitates the formation of high oxygen-excess modifications of the perovskites. The reactive precursor system yields fully hydrolysed gels almost without organic residues, but the gel absorbs CO2 from the air, leading to carbonate formation. The carbonate decomposition is the limiting step in oxide formation. Transport measurements of La0.67Ca0.33MnO3 films on LaAlO3 substrate show that all-alkoxide sol–gel derived films can compete with PLD films in terms of quality of epitaxy and transport. The somewhat different behaviour of the sol–gel derived films compared to PLD films is attributed to differences in morphology and oxygen stoichiometry.

We imitated the sandwich structure of TMR(Tunneling Magnetoresistance) to apply to CMR(Colossal Magnetoresistance) material . We choose one of the Colossal Magnetoresistance material La0.67Sr0.33MnO3(113) to be the Ferromagnetic(FM) layers as top and bottom layer in sandwich structure and use La0.67Sr0.33MnO3 ¡P SrO(214) to be middle layer which have Antiferromagnetic(AFM) property to form FM-AFM-FM structure. The FM and AFM layer can match their lattice in interface joint. What its purpose is to use this structure to enhance SPT (Spin Polarization Tunneling) effect and let spintronics can periodical spin-flip in supper lattice structure of antiferromagnetic. Upon this compose we try to show increase the LFMR (Low Field Magnetoresistance) by use CMR. The experiment result shows maybe the film structure damage occurred in our made TMR tunneling device process (ex. Ion etching process), so we should improvement the process to get the exactly experiment data. Additional, due to the alignment of the moment of La0.67Sr0.33MnO3 is unstable, the back and forth hysteresis loop can¡¦t overlap, So that afterwards we can use the more stable material La0.67Ca0.33MnO3 which have more stable moment.

Hydrogen is considered an important energy carrier for the XXI century. One of the processes involved in the production are the catalytic membrane reactors (CMR, Catalytic Membrane Reactor). This device is responsible for the production of synthesis gas (CO + H2) by the partial oxidation of fuels, such as methane. The families of LnMO3 perovskites (Ln = rare earth, M = transition metal) and its derived compositions represent an important class of materials with different electroceramic and of great interest from a technological standpoint properties, and may also be used for the manufacture of reactors membrane. In this context, this work aims at the synthesis and characterization of perovskite-type La0,6Sr0,4MO3 (M = Co, Mn, Fe) prepared by the amorphous citrate modified technique derived from the Pechini process. For the definition of synthetic samples of cobaltite doped lanthanum strontium (La0,6Sr0,4 CoO3) and manganite doped with strontium (La0,6Sr0,4MnO3) lanthanum procedure univariate and multivariate type 2x2 plans were made. While for the sample of lanthanum ferrite (LaFeO3) A slightly different approach was used. The main parameters (variables) considered in planning were: molar mass of hydroxyethyl cellulose (HEC), citric acid ratio: metal cation (AC:CM); drying temperature of the gel, and finally, temperature and time of calcination of the precursor. From the type of planning done in each case it was possible to define the most suitable conditions for obtaining a single-phase material, as well as a smaller crystallite size. The characterization techniques used were X-ray diffraction, thermal analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A notable aspect of this work is the sensitivity of the crystallographic phase obtained depending on the synthesis conditions. For this reason, knowledge of the chemical species present during the synthesis step is paramount to be obtained a material with appropriate characteristics. / O hidrogênio é considerado um vetor energético importante para este século XXI. Um dos processos que permitem a sua produção são os reatores de membrana catalítica (CMR, Catalytic Membrane Reactor). Este dispositivo é responsável pela produção de gás de síntese (CO + H2) através da oxidação parcial de combustíveis, por exemplo, o metano. As perovskitas da familía LnMO3 (Ln = terra rara; M = metal de transição) e suas composições derivadas representam uma classe importante de materiais eletrocerâmicos com propriedades diversas e de grande interesse do ponto de vista tecnológico, podendo inclusive serem utilizadas para a fabricação dos reatores de membrana. Neste contexto, este trabalho tem como objetivo a síntese e a caracterização de perovskitas do tipo La0,6Sr0,4MO3 (M = Co, Mn, Fe) preparadas através do processo do citrato amorfo modificado, técnica derivada do método Pechini. Para a definição do procedimento de síntese das amostras de cobaltita de lantânio dopada com estrôncio (La0,6Sr0,4CoO3 ) e de manganita de lantânio dopada com estrôncio (La0,6Sr0,4MnO3) foram realizados planejamentos univariados e multivariados do tipo 2x2. Enquanto que para a amostra de ferrita de lantânio (LaFeO3) uma abordagem um pouco distinta foi utilizada. Os principais parâmetros (variáveis) considerados no planejamento foram: massa molar da hidroxietilcelulose (HEC); proporção ácido cítrico : cátion metálico (AC:CM); temperatura de secagem do gel, e finalmente, temperatura e tempo de calcinação do precursor. A partir do tipo de planejamento realizado em cada caso foi possível definir as condições mais adequadas para a obtenção de um material monofásico, assim como um menor tamanho de cristalito. As técnicas de caracterização utilizadas foram: difração de Raios X, análise térmica, microscopia eletrônica de varredura (MEV) e microscopia eletrônica de transmissão (MET). Um aspecto notório deste trabalho é a sensibilidade da fase cristalográfica obtida em função das condições de síntese. Por este motivo, o conhecimento das espécies químicas presentes durante a etapa de síntese é primordial para que seja obtido um material com características adequadas.

No description available.

<p>  </p> <p>Cardiovascular disease has been the leading cause of death in the United States for over 70 years. To evaluate the extent and progression of cardiovascular disease, non-invasive imaging techniques are frequently used clinically and pre-clinically. Current echocardiographic and cine magnetic resonance approaches rely on measurements that are typically obtained from two-dimensional images, which assumes uniformity of the structure being evaluated. To explore methods to potentially address these shortcomings, our group has developed and validated high frequency four-dimensional ultrasound techniques as well as created a software toolbox that allows for measurement of myocardial kinematics. In this thesis, I assisted in the application of these methods to two murine models of disease states: myocardial infarction and aortic aneurysm. Another study I aided in focused on cardiac magnetic resonance imaging data from patients with Duchenne muscular dystrophy. From our software, we are able to obtain various strain and strain rate estimates that reveal significant functional changes in infarction and Duchenne muscular dystrophy earlier than standard measurement techniques. Furthermore, we are able to identify vascular expansion, transmural thickening, and changes in hemodynamics prior to aneurysm development. Earlier detection and localization allows for more targeted surveillance and interventions, which ultimately may result in improved clinical outcomes. Ideally, these findings can be used to expand the capabilities of cardiac research and the development of clinically applicable imaging techniques and treatments to better address underlying cardiovascular pathophysiology. </p>

One way of reducing the examination time in magnetic resonance imaging (MRI) is to reduce the amount of raw data acquired, by performing so-called undersampling. Conventionally, MRI data is acquired line-by-line on a Cartesian grid. In the field of Cardiovascular Magnetic Resonance (CMR), however, radial k-space sampling is seen as a promising emerging technique for rapid image acquisitions, mainly due to its robustness against motion disturbances occurring from the beating heart. Whereas Cartesian undersampling will result in image aliasing, radial undersampling will introduce streak artifacts. The objective of this work was to train the deep learning architecture, CycleGAN, to reduce streak artifacts in radially undersampled CMR images, and to evaluate the model performance. A benefit of using CycleGAN over other deep learning techniques for this application is that it can be trained on unpaired data. In this work, CycleGAN network was trained on 3060 radial and 2775 Cartesian unpaired CMR images acquired in human subjects to learn a mapping between the two image domains. The model was evaluated in comparison to images reconstructed using another emerging technique called GRASP. Whereas more investigation is warranted, the results are promising, suggesting that CycleGAN could be a viable method for effective streak-reduction in clinical applications.