Envirotainer builds containers that are specialized in transporting of temperature sensitive products these containers are customized for airplanes. The containers are then leased to other companies, most often to pharmaceutical companies. Envirotainer are based in Lagga, Knivsta. It is also here where the production of the containers is held. The container RAP T2 was designed in the early 80ies. The RAP T2 contains a fleet of about 1220 containers spread all over the world. This container model needs an update in order to optimize its performance. One of the improvements is achieved by optimizing the UA-value that is too high. A lower UA-value gives the performance of the container more endurance and more stability. Initial testing that was made in the beginning of the project showed that the floor in the container was the biggest stand alone module benefiter of the high UA-value. With that knowledge it was decided that my work should be about the possibility to improve the construction with a new insulation material that would optimize the UA-value. The work started off with an investigation of insulation materials. The most interesting insulation materials were weighted against each other. The result showed that Divinycell was the best insulation material for the design. Then different concepts were made, concept A were the whole floor was redesigned and concept B were an extra insulation module was designed to fit the existing floor. The concepts were weighted against each other in order to choose the final concept. Concept A was the best alternative and was chosen. The concept was then designed in PTC Creo. A prototype was built for UA-value testing. The prototype was then tested and measured against the original container in order to see how much the UA-value was lowered with the new design. And the result of the test showed an improvement of almost 37 %. The UA-value went from 25,40 W/K with the original container design to 16,05 W/K with the prototype design. This shows that an update of the floor design is in order to make the container performance better and more stabile.

Magnetic resonance imaging (MRI) is one of the most powerful imaging techniques for research and clinical diagnosis. To expand upon the intrinsic capabilities of MRI, new contrast agents that can detect the presence of biomarkers in vivo are being developed. My Masters thesis research focuses on the design and synthesis of a new MRI contrast agent that can detect glutathione (GSH), a biomarker that has been implicated in a number of oxidative stress diseases. This new MRI contrast agent is based on chelated dysprosium (Dy), an inorganic metal, which provides negative contrast to surrounding tissue. Preliminary data has shown that attaching a poly(ethylene glycol) (PEG) chain to the Dy chelate, effectively increasing its molecular weight, enhances the contrast ability of Dy. Using this new information, the contrast agent was designed to have a large molecular weight PEG chain attached to the Dy chelate through a disulfide, creating a thiol-sensitive linkage. In the presence of a thiol-containing molecule such as GSH, the Dy will be dePEGylated through a disulfide exchange reaction, removing the molecular weight effect of the PEG, and allowing for the detection of GSH by MRI. This new MRI contrast agent could provide insight into the progression and diagnosis of oxidative stress pathologies associated with GSH.

T2 relaxation imaging can be used to measure signal from water trapped between myelin bilayers; the ratio of myelin water signal to total water is termed the myelin water fraction (MWF). First, results from multi-component T2 relaxation and diffusion tensor imaging (DTI) were compared for 19 multiple sclerosis (MS) subjects at 1.5 T to better understand how each measure is affected by pathology. In particular, it was determined that the detection of a long-T2 signal within an MS lesion may be indicative of a different underlying pathology than is present in lesions without long-T2 signal. Next, the single-slice T2 relaxation measurement was implemented, refined, and validated at 3.0 T. Scan parameters were varied for phantoms and in-vivo brain, and changes in multi-exponential fit residuals and T2 distribution-derived parameters such as MWF were monitored to determine which scan parameters minimized artifacts. Measurements were compared between 1.5 T and 3.0 T for 10 healthy volunteers. MWF maps were qualitatively similar between field strengths. MWFs were significantly higher at 3.0 T than at 1.5 T, but with a strong correlation between measurements at the different field strengths. Due to long acquisition times, multi-component T2 relaxation has thus far been clinically infeasible. The next study aimed to validate a new 3D multi-component T2 relaxation imaging technique against the 2D single-slice technique most commonly used. Ten healthy volunteers were scanned with both the 2D single-slice and 3D techniques. MWF maps were qualitatively similar between scans. MWF values were highly correlated between the acquisition methods. Although MWF values were generally lower using the 3D technique, they were only significantly so for peripheral brain structures, likely due to increased sensitivity of slab-selective refocusing pulses used for the 3D approach. The 3D T2 relaxation sequence was then applied to the study of MS to take advantage of the increased brain coverage. Thirteen MS subjects and 11 controls underwent T2 relaxation and DTI examinations to produce histograms of MWF and several DTI-derived metrics. MS MWF histograms differed considerably from those of controls, and differences in MS MWF histograms did not mirror differences in DTI histograms relative to matched controls.

No description available.

Spinal cord injury (SCI) leads to axonal damage and limits the ability of the brain to communicate with the rest of the body. Several bioengineered approaches have been developed for the recovery of SCI. Among these techniques, degradable guidance tubes have shown promising results. However, design of nerve guide tubes requires several design considerations and has been a significant challenge. To assess the efficacy of a prototypical implanted nerve guide tubes, it is essential to perform continuous monitoring. In this respect, magnetic resonance imaging (MRI) is one of the most reliable imaging techniques as it offers the ability to achieve extraordinary high temporal and spatial resolution in addition to its non-invasive features. In spite of the excellent image quality of non-enhanced MRI various types of contrast agents have been developed to further enhance the contrast and allow improved visualization. The MRI contrast agents principally work by shortening the T1 or T2 relaxation times of protons located nearby. The presented study was intended to evaluate the in vitro degradation of the nerve guide tubes made of poly (lactic-co-glycolic acid) (PLGA). PLGA tubes incorporated with different concentrations of superparamagnetic iron oxide (SPIO) were scanned by MRI 3T on weekly basis during the degradation period. Spin-echo (SE) sequence with various echo times (TEs) ranged from 13.3 to 314.4 msec was applied. T2 mapping was computed using in-house algorithm developed in Matlab. Least square fit was used to find the slope of the decay curve by plotting log intensity on the y-axis and echo time on the x-axis. The average T2 values were calculated. Mass loss and water uptake of the degrading tubes were also measured weekly. Moreover, the micro-structural changes of the tubes were investigated using the scanning electron microscope (SEM). The MRI results showed that the concentration of SPIO affects the signal intensity of the T2 weighted images reducing the T2 relaxation time value. Accordingly, a linear correlation between SPIO concentration and T2 relaxation time was found. At the beginning of degradation, the SPIO nanoparticles were trapped within the polymeric network. Therefore, water penetration was the predominant factor affecting the T2 relaxation times. At week 5, a significant mass loss was observed. From this stage onwards, the trapped SPIO were released from the polymeric network increasing T2 relaxation time dramatically. According to SEM images, the size of the pores in PLGA guide tubes was increased with the degradation. Approaching the end of degradation, shrinkage of the tubes was observed and the degraded nerve guide tubes were shown to be collapsed. Similar shape variation was observed in T2 weighted MR images. In summary, this study provided an approach to non-invasive monitoring of degradation behavior of nerve guide tubes using contrast enhancement. The developed technique is of great importance since it opened an insight to non-invasive monitoring of tissue engineered scaffolds for in vivo studies.

Activities associated with, or interacting with, leukaemic cell populations were assayed for the ability to influence in vitro haematopoiesis. The first of these, the glycoprotein leukaemia inhibitory factor (LIF), has a role in aspects of murine, non human primate and human haematopoiesis. It is thought to be particularly important in the development of megakaryocytes and is also known to induce the terminal differentiation of certain leukaemic cell lines. LIF was assayed both for direct and indirect effects on the proliferation of haematopoietic precursor cell populations in vitro. As a direct acting agent in semi-solid agar culture of haematopoietic cell populations derived from normal bone marrow or 15 day foetal liver, LIF was unable to support colony formation. In cultures of cells derived from normal bone marrow stimulated with single, or combinations of, growth factors, the addition of LIF had no statistically significant effect on the level of colony formation. In cultures of cells derived from foetal liver, stimulated with particular growth factor combinations (medium conditioned by the Wehi3B leukaemic cell line + medium conditioned by the lung fibroblast cell line, L929); GM-CSF + M-CSF; IL-la + IL-3 + M-CSF), LIF, was shown to decrease the level of colony formation. LIF did not directly alter the proportion of the population in DNA synthesis in cell populations derived from normal femoral marrow, 15 day foetal liver or y- irradiated femoral marrow. As an indirect acting agent LIF failed to block the synthesis of a stem cell stimulator, or it's action, on a population of high proliferative potential colony forming cells derived from normal femoral marrow, cloned in the presence of Wehicm+L929cm. (HPP-CFC (Wehicm + L929cm)) LIF's actions on clones of a murine myeloid leukaemia (SA2JMB1) were also assessed. LIF had no statistically significant effect on colony formation or the level of DNA synthesis in populations of SA2JMB1 leukaemic cells. A second group of associated activities was produced by the X- irradiation induced murine myeloid leukaemia (SA2JMB1). Medium conditioned by the leukaemic cells was assayed in vitro both for direct and indirect effects on the proliferation of haematopoietic cells derived from femoral marrow. As a direct acting agent in 7 and 14-day semi-solid agar culture of femoral marrow, leukaemic conditioned medium alone stimulated limited colony formation. In 7 and 14 day cultures stimulated with single and combinations of specific colony stimulating factors: (rmGM-CSF, rhM-CSF, rhIL-1a) a significant increase in colony number was noted in all cases when cultures were supplemented with leukaemic conditioned medium. SA2JMBlcm was shown to support the proliferation of an IL-3 dependent cell line (FDCP-A4 cells). The colony enhancing ability of SA2JMBlcm was shown to be blocked by pretreatment with antibodies to IL-3. This suggested that SA2JMB1 conditioned medium contained IL-3 or an IL-3 like activity, as one of its components. The conditioned medium failed to directly alter the level of DNA synthesis in a population of HPP-CFC (Wehicm+L929cm) derived from normal bone marrow or y- irradiated bone marrow. As an indirect acting agent the conditioned medium did block the action of a stem cell proliferation stimulator on normal bone marrow derived HPP-CFC (Wehicm+L929cm). This leukaemia associated activity was shown to be larger than 50KD, sensitive to heat treatment and able to act in a different manner to the stem cell inhibitor MIP-1-a. Thus this novel activity may be important in blocking stimulator action in haematopoietic stem cells and thus contribute to the haematopoietic insufficiency seen in leukaemia.

T2 relaxation imaging can be used to measure signal from water trapped between myelin bilayers; the ratio of myelin water signal to total water is termed the myelin water fraction (MWF). First, results from multi-component T2 relaxation and diffusion tensor imaging (DTI) were compared for 19 multiple sclerosis (MS) subjects at 1.5 T to better understand how each measure is affected by pathology. In particular, it was determined that the detection of a long-T2 signal within an MS lesion may be indicative of a different underlying pathology than is present in lesions without long-T2 signal. Next, the single-slice T2 relaxation measurement was implemented, refined, and validated at 3.0 T. Scan parameters were varied for phantoms and in-vivo brain, and changes in multi-exponential fit residuals and T2 distribution-derived parameters such as MWF were monitored to determine which scan parameters minimized artifacts. Measurements were compared between 1.5 T and 3.0 T for 10 healthy volunteers. MWF maps were qualitatively similar between field strengths. MWFs were significantly higher at 3.0 T than at 1.5 T, but with a strong correlation between measurements at the different field strengths. Due to long acquisition times, multi-component T2 relaxation has thus far been clinically infeasible. The next study aimed to validate a new 3D multi-component T2 relaxation imaging technique against the 2D single-slice technique most commonly used. Ten healthy volunteers were scanned with both the 2D single-slice and 3D techniques. MWF maps were qualitatively similar between scans. MWF values were highly correlated between the acquisition methods. Although MWF values were generally lower using the 3D technique, they were only significantly so for peripheral brain structures, likely due to increased sensitivity of slab-selective refocusing pulses used for the 3D approach. The 3D T2 relaxation sequence was then applied to the study of MS to take advantage of the increased brain coverage. Thirteen MS subjects and 11 controls underwent T2 relaxation and DTI examinations to produce histograms of MWF and several DTI-derived metrics. MS MWF histograms differed considerably from those of controls, and differences in MS MWF histograms did not mirror differences in DTI histograms relative to matched controls. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

L'arthrose est une maladie commune observée dans les populations vieillissantes caractérisée par une affection dégénérative du cartilage articulaire. Le diagnostic clinique de la maladie repose sur la radiographie conventionnelle. Cette technique permet de mettre en évidence les modifications de l'os liées à l'arthrose (géodes, condensation de l'os sous-chondral, et ostéophytes) mais n'offre pas une vision directe du cartilage. Grâce à sa résolution spatiale et son contraste tissulaire élevé, l'IRM individualise le cartilage et le différencie des structures adjacentes (os, tissu synovial, ménisques et liquide synovial). Nous avons mis à profit les potentialités de l'IRM à haut champ (7 Teslas) pour suivre, in vivo, les modifications du cartilage de l'articulation fémoro-tibiale chez le rat, au cours du processus de maturation/vieillissement ainsi que dans un modèle d'arthrose expérimentale (section du ligament croisé antérieur). Ces travaux ont montré une diminution du volume et des épaisseurs cartilagineuses liée à l'âge, tout comme des pertes chondrales fémorales et un œdème du cartilage tibial dans le genou arthrosique. Dans une seconde partie, nous avons appliqué les méthodes de cartographie T2 et de mesures volumiques (à 1,5 T) afin de déterminer les variations survenant au sein du cartilage rotulien humain vieillissant. Ces travaux attestent de la capacité de la cartographie T2 à détecter des modifications matricielles avant l'apparition de réelles pertes chondrales. Enfin, notre dernière étude, toujours à 1,5 T, concerne la quantification du volume et de l'activité de la membrane synoviale inflammatoire dans une cohorte de patients souffrant de gonarthrose. / Osteoarthritis (OA) is a common disease observed in elderly population and characterized by a progressive destruction of cartilaginous tissue. The clinical diagnosis of this disease is realized by conventional radiography. This method allows visualizing bone modifications related to OA disease (cysts, subchondral bone thickening, and osteophytes) but is unable to assess directly cartilage structure. Due to its high spatial resolution and high contrast between tissues, Magnetic Resonance Imaging (MRI) is able to visualize the cartilage structure and to differentiate it from adjacent structures (bone, synovial tissue, menisci, and synovial fluid). We have employed MRI potentialities at high magnetic field (7 Teslas) to follow, in vivo, cartilage modifications in the rat femoro-tibial articulation. This methodology was used to evaluate normal cartilage ageing-process and to assess an experimental OA model (anterior cruciate ligament transaction). These works showed an age-related cartilage volumetric and thickness decrease, as well as femoral cartilage damages and tibial cartilage oedema in OA knees. In a second part of our work, we applied T2 mapping and volumetric techniques (at 1.5 T) to determine variations which occur in the elderly human patellar cartilage. Results demonstrated the capacity of T2 mapping to early detect matricial modifications before any cartilage volumetric impact can be found. At least, our last study, always at 1.5 T, focused on the synovial membrane volume and inflammatory activity by taking into account a human population suffering from knee OA.

Purpose: The purpose of this study was two-fold: (1) determine if muscle activation was greater in a BFR exercise condition compared to non-BFR exercise condition using MRI T2 mapping, and (2) determine if the muscle activation for both BFR and non-BFR exercise conditions differs between postbariatric surgery individuals and individuals in 2 control groups. Methods: Three groups participated: (1) a normal-BMI group, (2) a postbariatric surgery group, and (3) a matched group for the surgery individuals. Ultrasound imaging was used to find the optimal BFR pressure for each participant. All participants participated in both BFR and non-BFR exercises. Using a 3-Telsa MRI, a T2 map was imaged prior to and immediately following exercise. Analyses included within-group-across-condition comparisons and within-condition-across-group comparisons. The outcome variable of interest was the change in muscle activation determined via T2 mapping. Results: There was no statistical difference in the increase in muscle activation between BFR and non-BFR exercise conditions (p-value range 0.1091 to 0.9166). When comparing groups across conditions, we found that the surgery group elicited a significantly greater increase in activation compared to the normal-BMI group in every condition (p-value range 0.0014 to 0.0217) and in several muscles when compared to the matched group (p-value range 0.0060 to 0.0311). Other muscles compared to the matched group were not significantly different (p-value range 0.0683 to 0.129). No difference was found between the control groups (p-value range 0.2041 to 0.9557) in muscle activation for either condition. Conclusion: These results did not suggest a difference between BFR exercise and non-BFR exercise for the calf-raise protocol. Postbariatric surgery patients elicited an equal muscle activation response in some conditions and a greater muscle activation response in others when compared to both control groups. Further research is needed to determine whether a greater intensity or duration of exercise is needed to elicit an acute response to BFR and what factors are contributing to the increased muscle activation seen in the postbariatric surgery group.

Spinal cord injury (SCI) leads to axonal damage and limits the ability of the brain to communicate with the rest of the body. Several bioengineered approaches have been developed for the recovery of SCI. Among these techniques, degradable guidance tubes have shown promising results. However, design of nerve guide tubes requires several design considerations and has been a significant challenge. To assess the efficacy of a prototypical implanted nerve guide tubes, it is essential to perform continuous monitoring. In this respect, magnetic resonance imaging (MRI) is one of the most reliable imaging techniques as it offers the ability to achieve extraordinary high temporal and spatial resolution in addition to its non-invasive features. In spite of the excellent image quality of non-enhanced MRI various types of contrast agents have been developed to further enhance the contrast and allow improved visualization. The MRI contrast agents principally work by shortening the T1 or T2 relaxation times of protons located nearby. The presented study was intended to evaluate the in vitro degradation of the nerve guide tubes made of poly (lactic-co-glycolic acid) (PLGA). PLGA tubes incorporated with different concentrations of superparamagnetic iron oxide (SPIO) were scanned by MRI 3T on weekly basis during the degradation period. Spin-echo (SE) sequence with various echo times (TEs) ranged from 13.3 to 314.4 msec was applied. T2 mapping was computed using in-house algorithm developed in Matlab. Least square fit was used to find the slope of the decay curve by plotting log intensity on the y-axis and echo time on the x-axis. The average T2 values were calculated. Mass loss and water uptake of the degrading tubes were also measured weekly. Moreover, the micro-structural changes of the tubes were investigated using the scanning electron microscope (SEM). The MRI results showed that the concentration of SPIO affects the signal intensity of the T2 weighted images reducing the T2 relaxation time value. Accordingly, a linear correlation between SPIO concentration and T2 relaxation time was found. At the beginning of degradation, the SPIO nanoparticles were trapped within the polymeric network. Therefore, water penetration was the predominant factor affecting the T2 relaxation times. At week 5, a significant mass loss was observed. From this stage onwards, the trapped SPIO were released from the polymeric network increasing T2 relaxation time dramatically. According to SEM images, the size of the pores in PLGA guide tubes was increased with the degradation. Approaching the end of degradation, shrinkage of the tubes was observed and the degraded nerve guide tubes were shown to be collapsed. Similar shape variation was observed in T2 weighted MR images. In summary, this study provided an approach to non-invasive monitoring of degradation behavior of nerve guide tubes using contrast enhancement. The developed technique is of great importance since it opened an insight to non-invasive monitoring of tissue engineered scaffolds for in vivo studies.