Master of Science in Biomedical Sciences / Department of Clinical Sciences / Jessica Meekins / Objectives- To determine the effect of oral robenacoxib on experimentally-induced anterior uveitis, and to evaluate the ability of robenacoxib to cross an intact blood-aqueous barrier. Animals- Twelve healthy adult domestic shorthair cats. Procedures- Cats in the treatment group (n=6) received oral robenacoxib (1.51 ± 0.36 mg/kg ) once daily beginning 1 day before experimental induction of uveitis by anterior chamber paracentesis (ACP) and continuing 1 day after paracentesis. Anterior chamber paracentesis was performed using a 30 g needle attached to a 1 mL syringe, and 100 µL of aqueous humor were aspirated over 3-5 seconds. Anterior chamber fluorophotometry was performed in both eyes of each cat immediately before ACP (time 0), and at 6, 24, and 48 hours after ACP. An independent t-test was used to compare percent fluorescein increase in treatment versus control cats at each time point. Values of p<0.05 were considered significant. Concentrations of robenacoxib in aqueous humor were measured using liquid chromatography and mass spectrometry. Results- There was no statistically significant difference between the ACP and control eye at time 0 (p=0.322). When comparing the percent fluorescein increase between treatment and control groups, there was no statistically significant difference at any time point (p>0.05). Robenacoxib was present in small but detectable levels in 5/6 cats in the treatment group. Conclusions and clinical relevance- Administration of oral robenacoxib did not significantly lessen experimentally-induced anterior uveitis in normal cats, as assessed by fluorophotometry. Low concentrations of aqueous humor robenacoxib were detectable in the majority of cats receiving the drug.

Despite the prevalence of CNS disorders, treatment options for CNS disorders fall woefully behind treatment options for other systemic disorders. This is due to the presence of the blood brain barrier (BBB) acting as an obstacle, preventing foreign substances from entering the brain. A newly developed and innovative biomedical procedure attempts to bypass the BBB in the delivery of therapeutics by using focused ultrasound (FUS) to disrupt and temporarily open the BBB. The use of FUS-facilitated BBB opening is able to target specific tissue for noninvasive, localized BBB penetration. As the technique is experimental and in it's nascent stage of development, there are only a few studies that investigate its abilities in delivering treatments directly to the brain. The studies involve delivery of large, hydrophilic molecules that traditionally would not be able to bypass the BBB and enter the brain, and analysis of CNS concentrations of the molecules after FUS treatment, as well as the therapeutic successes. Results of FUS the studies are promising and the results demonstrate that the procedure is able to significantly increase drug concentrations in the brain, increase survival rates in animal models, decrease tumor growth, and decrease tumor margins and volume. The potential and power of FUS should be further explored as the future of CNS disorder treatments.

Background: Celiac Disease (CD) is a chronic, autoimmune disease that prevents individuals from being able to process gluten. When individuals ingest gluten, their digestive system becomes severely damaged, leading to many adverse, health effects. It is, therefore, significantly crucial that individuals with CD adhere to a Gluten-Free diet (GFD). However, the adherence rate is well below optimal in the adult, CD population. Hence, it is crucial to identify and understand the factors that impact their ability to maintain a GFD. Objective: To develop a systematic review that critically appraises and synthesizes evidence on the facilitators and barriers that affect adherence to GFD among the adult population with CD. Data Sources: Ovid Medline, CINAHL, PsychInfo, and Embase were included, using a combination of keywords to retrieve relevant articles. The Inclusion Criteria consisted of empirical studies that focus on Adults with CD. Only English studies were considered. A coding scheme was developed to retrieve uniform information from each of the included studies, including: study design, population characteristics, facilitators and barriers presented, limitations, and a summary of each study. Results: Facilitators and Barriers were organized based on a Social ecological model, derived from the bioecological theory of development, which emphasizes that individuals make choices in their lives based on the impact of various ecological levels that exist. The ecological levels include: System, Community, Organizational, Interpersonal, and Individual. The studies included in this systematic review reported many facilitators and barriers that exist at the different ecological levels, which significantly affect adherence to GFD. Based on the frequency of articles that reported each facilitator and each of the studies’ level of evidence, the most significant facilitators were: increased patient education; celiac association membership; financial compensation/food subsidies; and increased intention/self-regulatory efficacy. When taking into consideration the frequency of articles that reported each barrier along with each of the studies’ level of evidence, the most significant barriers were: restaurant dining/supermarket shopping; poor patient education from practitioner; specific cultural factors; and low intention/motivation to adhere to a GFD. Although other factors have been reported, there was limited evidence to support them due to weak study designs, limited samples, and inconsistencies found across the different studies. It is important to understand that there are many additional facilitators and barriers retrieved in the systematic review that do not have as much evidence to support them. These are discussed in the thesis. Conclusion: Introducing policy changes at a health systems level will have the most influential impact on all the ecological layers in an individual’s life. Based on the magnitude of the results and the level of evidence of each of the studies, improvements to physician-patient communication, patient education interventions, and food subsidies, will create the most significant opportunity to positively impact the remaining ecological levels in one’s life, with the ultimate goal of improving adherence rates to a GFD among adults with CD in Canada. Registration: Prospero registration ID number is CRD42018091854.

Dissertation Master of Technology Mechanical Engineering Faculty of Engineering Cape Peninsula University of Technology 2014 / Thermal Barrier Coatings (TBC’s) created by Electron Beam Physical Vapour Deposition (EB-PVD) are widely used in the aerospace industry. Advancements in the field however are hindered by the cost and time required for research and development. Hence, there exists a need for a more comprehensive understanding of coating parameter interactions to better predict response values without the need for extensive pre-production testing. This thesis seeks to provide a response surface for EB-PVD coatings, by investigating the following EB- PVD independent input variables: electron beam emission current, gas ratio, vacuum pressure, substrate temperature, roughness and process time in order to generate a predictive statistical model. Output variables were numerous, however emphasis was placed on: TBC coating thickness and density of columns generated during the process. It is impossible to select an “optimum process recipe”; rather, there exists many optimal combinations suited to specific coating structure and its application. Therein lies the need for this model, able to predict TBC properties according to input variables. Using ALD’s Smart Coater (ALD Vacuum Technologies GmbH), a ceramic top coat (Yttria partially stabilized zirconia, YPSZ, ZrO2-7%Y2O3) was deposited onto 40x30x5mm Inconel 617 samples with NiAl bond coat. These samples were subsequently tested to determine coating properties. The research will show that the complex nature of EB-PVD TBCs may be simplified, at least to a certain degree through a statistical analysis of the interactions between process variables.

Este estudo teve como finalidade, testar uma barreira contra a contaminação microbiológica em placas de contato, utilizadas em monitoramento de salas limpas para fabricação de produtos farmacêuticos estéreis. Durante o ano de 2007, foram realizados testes de contato com a utilização da mencionada barreira, e os resultados foram comparados com dados dos anos de, 2004, 2005 e 2006, quando a barreira não foi utilizada. Os ambientes utilizados para os testes foram duas salas limpas de uma planta farmacêutica localizada no Rio de Janeiro. Nos mencionados ambientes é necessário o uso de uma vestimenta especial, de forma a evitar que partículas do corpo dos operadores, bactérias e fungos, migrem para a superfície externa do uniforme e coloquem em risco a esterilidade dos produtos. Sendo assim, foi proposta a colocação de uma camiseta diretamente sobre a pele do operador durante todo o ano de 2007 de forma a evitar ou reduzir a possibilidade de migração dessas partículas; e os resultados foram comparados com os anos de 2004, 2005 e 2006, quando a camiseta não foi usada. Os testes demonstraram que houve uma redução de cerca de 50% na ocorrência de placas contaminadas. Com relação ao número total de colônias formadas, a redução foi de 75% na comparação com os anos de 2004 e 2005 e de 50% com relação ao ano de 2006 / This study had as objective to test a barrier against microbiological contamination in contact plates that are used in sterile pharmaceutical products clean rooms monitoring. During 2007 the tests were performed and compared with data from, 2004, 2005 and 2006, when the mentioned barrier was not used. The test environments were two clean rooms from a pharmaceutical plant located at Rio de Janeiro. In the mentioned environments the use of special garments is necessary for avoiding that particles from operators bodies, bacteria and most remain in contact with the room environment, adding risk to the sterilized products. So, it was proposed the use of undershirt between the garment and the operator skin for reducing the contact plates contamination during the regular rooms monitoring. This undershirt was used during 2007 and the results were compared with the samples of 2004, 2005 and 2006 when the undershirt was not used. The results demonstrated that it was obtained a reduction of about 50% in relation to contaminated plates. In relation to the total number of colonies the reduction was 75% in comparison with 2004 and 2005, and 50% in comparison with 2006

Magister Scientiae (Medical Bioscience) - MSc(MBS) / Alcohol abuse is a growing crisis within South Africa, with severe health and socio-economic implications. Alcohol compromises the function of the blood-brain barrier (BBB), and thus its ability to regulate the homeostatic environment of the CNS is interrupted. In this study, an in vitro model of the BBB was utilized to study the effects of selected concentrations of alcohol (25mM-200mM) and the ameliorating effects of fermented rooibos (Aspalathus linearis) (0.003125%-1%), in an attempt to reverse the harmful oxidative effects of alcohol. The literature clearly states that alcohol (ethanol) compromises the BBB by reactive oxygen species (ROS) production and, therefore, rooibos, a shrub high in antioxidants and widely utilized nationally, was added to alcohol-exposed mouse brain endothelial (bEnd5) cells with the view to reverse the alcohol-induced effects on the BBB model. Alcohol-treated (25mM-400mM) bEnd5 monolayers expressed no toxicity, however, cell numbers were significantly suppressed (P<0.0274). To validate this finding, the activity of the mitochondria was investigated in order to understand if the cell’s metabolism was related to the decrease in cell division. Results showed that for both acute and chronic exposure there was a decrease in mitochondrial activity (MA) for a period of 24-48 hours, thereafter, the MA of the bEnd5 cells returned to normality. However, in experiments which chronically (600mM and 800mM) exposed cells to alcohol over a period of 96 hours, MA was suppressed and did not return to normal. Fermented rooibos caused a biphasic response to cellular proliferation at 24-72 hours, where the lower concentrations (0.0625-0.125 %) caused an increase in cellular proliferation and the higher concentrations (0.5-1%) resulted in a relative decrease in cellular proliferation. The long-term effect, after acute exposure, however, resulted in cell suppression at 96 hours (P<0.0073). With respect to the MA, bEnd5 cells exposed to fermented rooibos showed that lower concentrations (0.003125-0.0125%) were suppressed at 24 hours and was elevated at 48 hours and96 hours for all concentrations. The exception being the highest concentration (0.1%), which showed a depression in MA (P<0.05). Treating cells with both alcohol and rooibos, resulted in exacerbated suppressing of the MA. The physiological function of the BBB model was investigated by monitoring the permeability using transendothelial electrical resistance (TEER) studies and the in vitro model used in this study was endorsed for the first time using high resolution scanning electron microscopy. TEER indicated incidental changes in the permeability, only at 24 hours, for both acute and chronic exposure to alcohol and rooibos. A novel finding, within this study, was the increase in electrical resistance across the formation of the cell monolayer, after treatment with alcohol. The data lead to the hypothesis for the effect of ROS on resistivity and provides a rationale to explain the effects of combinatory treatments that were expected to ameliorate the negative effect of alcohol, however, this study showed synergistically negative effects on the bEnd5 cells. In summary the main findings in this study were: (a) alcohol was not toxic on bEnd5cells, (b) alcohol increased the permeability across monolayers of bEnd5 cells and(c) rooibos did not significantly reverse the ROS-induced effects of alcohol, but exacerbated the effects. Rooibos treatment caused the following: (i) biphasic effect on cellular proliferation, (ii) an increase in MA, and (iii) a cyclic effect in TEER studies.

Evaluation and characterisation of thermal barrier coatings (TBCs) have been conducted correlating microstructure with physical and mechanical properties, to further understand TBC failure mechanisms and performances in this thesis. A modified four-point bending test was employed to investigate the interfacial toughness of atmospheric plasma sprayed TBCs. The delamination of the TBCs occurred mainly within the topcoat. The energy release rate increased from ~50 J/m-2 for as-sprayed conditions to ~120 J/m-2 after annealing at 1150 ºC for 200 hours with a loading phase angle about 42º. Micro X-ray tomography revealed how various types of imperfections developed near the interface and the 3D interface was characterised. Stress measurements by photoluminescence piezospectroscopy (PLPS) and analytical solutions were combined to investigate the local stress around spherically symmetrical portions of a TGO layer formed on Fecralloy. Spherical indenters were used to create curvature with different curvature radii and depths on alloys. The effect of curvature radius on stress was found to be more significant than the depth of local curved area. TGO stress as a function of oxidation time at the curved areas was also discussed. Electron beam physical vapour deposited (EBPVD) TBCs with a β-(Ni,Pt)Al bond coat on CMSX4 substrate were investigated by micro X-ray computed tomography (XCT). The 3D microstructures evolution and damage accumulation were studied. 3D interfacial roughness was calculated and compared to scanning electron microscope image analysis. The calculated interfacial roughness did not change much even after 200 thermal cycles, indicating there was not obvious rumpling in this TBCs sample. Commercial simple and Pt-modified aluminide coatings were studied and compared. Both coatings consisted mainly of β-NiAl phase. Thermogravimetric analysis (TGA) tests indicated that the Pt-modified aluminide coating was much more resistive for oxidation than simple aluminide coating. Instrumented indentation was used to measure the mechanical properties, showing the coatings had similar young’s modulus around 130 GPa while Pt-modified aluminide coating was more ductile and had a higher fracture toughness than simple aluminide coating. The Raman spectra of yttria-stabilised zirconia (YSZ) in the temperature range of 25-1100 ºC were investigated. The peak shift and broadening were carefully analysed. The thermal mismatch stress was found to have a negligible effect on the Raman shift. The dependence can be used to monitor the temperature in YSZ without contact.

Bond coats used in thermal barrier coatings (TBCs) for gas-turbine engine applications are studied in this thesis, with a focus on oxidation behaviour, surface rumpling and stress evolution. Bond coats made of γ/γ’ Ni-Al-Pt alloys have been widely used in TBCs and it has been found that addition of platinum greatly improves the oxidation resistance of the coatings. The mechanisms behind this benefit, however, are not well understood. For this reason, the oxidation behaviour of four γ/γ’ Ni-20Al-xPt (x= 0, 5, 10 and 15 at. %) alloys at 1150 °C is studied and compared in terms of oxide spallation, oxide microstructure and growth, residual stress in the oxide scale and oxide/alloy interface morphology. The progressive increase of platinum addition into the alloys results in (1) greater resistance to oxide spallation, (2) reduction in oxidation of nickel, (3) lower stresses in the α-Al2O3 scale and (4) more planar oxide/alloy interfaces. It is found that the selective oxidation of aluminium promoted by platinum plays a central role in the evolution of the oxidation behaviour of the alloys. Surface rumpling of a NiCoCrAlY bond coat deposited on a Ni-base superalloy during cyclic oxidation at 1150 °C is studied. The extent of rumpling is found to depend on thermal history, coating thickness and exposure atmosphere. While the coating surface progressively roughens with cyclic oxidation, bulk NiCoCrAlY alloys with the same nominal composition show a much less tendency to rumple under the same thermal cycling condition. The coatings, especially the thin ones, experience substantial degradation (e.g. β to γ phase transformation and exhaustion of yttrium) induced by oxidation and coating/substrate interdiffusion during thermal exposure. The observations together suggest that rumpling is driven by the lateral growth of the thermally grown oxide (TGO) and the coating deforms in compliance with the TGO. While the dependence of rumpling development on experimental conditions is generally in agreement with the prediction of the existing model, it is suggested that the degradation of the NiCoCrAlY coating and its dependence on coating thickness need to be taken into consideration when predicting the rumpling development of NiCoCrAlY coatings. The residual stresses in a NiCoCrAlY bond coat deposited on a Ni-base superalloy are studied by X-ray diffraction using the sin2Ψ technique. The stresses at room temperature are found to be tensile; they first increase and then decrease with oxidation time. The stress develops and builds up upon cooling, predominantly within the temperature range from 1150 °C to 600 °C. Due to the limited penetration depth into the bond coat, the X-ray only probes the stress in a thin surface layer consisting of a single γ-phase formed through aluminium depletion during oxidation. Above 600 °C, the volume fraction of the β-phase in the bond coat increases with decreasing temperature. The mechanisms of stress generation in the coating are examined and discussed based on experiments designed to isolate the contribution of possible stress generation factors. It is found that the measured bond coat stresses are mainly induced by the volume change of the bond coat associated with the precipitation of the β-phase upon cooling.

Dendritic cells (DCs) form a key component of the immune response, as they are involved in the innate and adaptive immunity and in the process of tolerance. Under normal conditions, DCs are absent from the Central Nervous System (CNS), as the blood brain barrier (BBB) restricts their entry. However, DCs have recently been implicated in the pathogenesis of several CNS diseases. The molecular mechanisms that mediate DC trafficking across the BBB are poorly understood. The objectives of this study were to examine the role of endothelial cell adhesion molecules (eCAMs) and their ligands in the process of DC adhesion to the BBB endothelium, and to investigate the participation of DCs in human CNS diseases. To study DC adhesion, DCs were generated in vitro by culturing human blood monocytes in the presence of GM-CSF and IL- 4, and DC maturation was induced by adding inflammatory cytokines (TNF-α, IL-1β, IL-6) and PGE₂. Immature and mature DCs displayed differences in their expression of surface molecules, including eCAM ligands, by flow cytometry. Adhesion to the cerebral endothelium was investigated using an in vitro model of the BBB consisting of primary cultures of human brain microvessel endothelial cells (HBMEC). Immature or mature DCs were incubated with resting or TNF-α-activated HBMEC for up to one hour. Only a few DCs adhered to resting HBMEC, but adhesion was upregulated upon activating HBMEC (p<O.Ol). Moreover, immature DCs adhered to activated HBMEC to a greater extent compared to mature DCs (p<O.OOl). Blocking experiments indicated that the adhesion of both immature and mature DCs to HBMEC was dependent upon ICAM-1-CD18 or ICAM-2-CD18, ICAM-2-DC-SIGN, and PECAM-l PECAM-l interactions. In addition, VCAM-1-VLA-4 interactions mediated the adhesion of immature but not mature DCs to activated HBMEC. Using immunohistochemistry for DC markers, we also examined the presence of DCs in human inflammatory, infectious, and neurodegenerative diseases, stroke and tumours. The results indicate accumulation of DC SIGN—, fascin—, and MHC class Il—expressing DCs in the CNS under most pathological conditions. These findings provide further insight into the mechanisms of neuroinflammation, and highlight the role of DCs and the BBB endothelium in this process. / Medicine, Faculty of / Medicine, Department of / Experimental Medicine, Division of / Graduate

This thesis will present the synthesis, characterization and magnetic measurements of lanthanide complexes with varying nuclearities (Ln, Ln2, Ln3 and Ln4). EuIII, GdIII, TbIII, DyIII, HoIII and YbIII have been selected as the metal centers. Eight polydentate Schiff-base ligands have been synthesized with N- and mostly O-based coordination environments which chelate 7-, 8- or 9-coordinate lanthanide ions. The molecular structures were characterized by single crystal X-ray crystallography and the magnetic properties were measured using a SQUID magnetometer. Each chapter consists of crystal structures and magnetic measurements for complexes with the same nuclearity. There are eight DyIII SMMs in this thesis which are discrete molecules that act as magnets below a certain temperature called their blocking temperature. This phenomenon results from an appreciable spin ground state (S) as well as negative uni-axial anisotropy (D), both present in lanthanide ions owing to their f electron shell, generating an effective energy barrier for the reversal of the magnetization (Ueff). The ab initio calculations are also included for the SMMs with high anisotropic energy barriers to understand the mechanisms of slow magnetic relaxation in these systems.