Mucinas são glicoproteínas altamente O-glicosiladas cuja principal característica estrutural é a presença de -GalNAc ligado aos resíduos hidroxilados de serina e treonina. Em alterações celulares malignas, esse núcleo é exposto como um antígeno carboidrato associado a tumor (Tn) e sua alta expressão em células cancerosas faz dele um alvo para o desenvolvimento de abordagens contra o câncer. Mucinas de Trypanosoma cruzi, agente etiológico da Doença de Chagas, apresentam -GlcNAc ligado à apoproteína, envolvido no processo de sialilação catalisado pela enzima fundamental trans-sialidase (TcTS) mediadora da invasão celular. Sendo o componente glicosídico do antígeno Tn um análogo estrutural e funcional de -GlcNAc, pode influenciar na atividade de TcTS, alvo terapêutico para a Doença de Chagas. Neste contexto, foram sintetizados glicopeptídeos lineares e cíclicos derivados de GalNAc mimetizando sua ocorrência em mucinas tumorais e parasitárias. Doadores e aceptores glicosídicos convenientemente protegidos foram preparados e ligados entre si com -estereosseletividade por dois métodos de glicosilação: perclorato/carbonato de prata (promotor clássico de referência) e brometo de mercúrio (promotor pela primeira vez utilizado para doadores glicosídicos do tipo azidocloreto). Os blocos de glicoaminoácidos obtidos foram acoplados a um segundo resíduo, formando glicodipeptídeos lineares inéditos, que originaram glicodicetopiperazinas funcionalizadas com -GalNAc, igualmente inéditas a literatura, mediante a etapa de desproteção/ciclização. Glicoaminoácidos intermediários contendo -GalNAc foram desprotegidos e submetidos a ensaios de cinética enzimática em TcTS, apresentando expressiva inibição de 57% a 79% da atividade da enzima. Os mesmos blocos foram avaliados quanto à citotoxicidade em células tumorais, apresentando entre 73% e 79% de morte celular na linhagem Jurkat e cerca de 30% na linhagem B16F10. Os resultados ensaios biológicos sugerem que os compostos de interesse preparados podem atuar como inibidores da enzima TcTS e agentes de citotoxicidade seletiva em células tumorais. / Mucins are heavily O-glycosylated glycoproteins which major feature being the presence of -GalNAc bound to hydroxylated protein residues of serine and threonine. In malignant cell transformation this core is exposed as a tumor associated carbohydrate antigen (Tn), and its high-level expression in cancer cells turns it into a target for developing anticancer approaches. Mucins from Trypanosoma cruzi, aetiologic agent of Chagas Disease, display -GlcNAc linking glycans to the apoprotein, involved in the sialilation process catalized by tran-sialidase enzyme (TcTS), essential cell invasion by the parasite. Being Tn antigen an structural and functional analogue of -GlcNAc, it may interfere on TcTS, a therapeutic target Chagas Disease. In this context, linear and cyclic glycopeptides containing GalNAc were synthesized, mimicking their natural occurrence in tumoral and parasite mucins. Glycosidic donors and acceptors, conveniently protected were prepared and bound to each other with -stereoselectivity, though two glycosylation methods: silver perchlorate/carbonate (classical reference promoter) and mercuric bromide (first used as a promoter for azidochloride donors). Glycoaminoacids building blocks obtained were coupled to a second residue, furnishing novel linear glycopeptides, which generated glicodiketopiperazines functionalized with -GalNAc, equally unpublished, upon deprotection/cyclization step. Intermediate -GalNAc-containing glycoaminoacids were deprotected and subjected to kinetic enzymatic assay on TcTS, showing expressive enzyme activity inhibition from 57% to 79%. The same compounds were assessed for cytotoxicity on tumoral cells, showing from 73% to 79% of death for Jurkat cells and about 30% for B16F10 cells. Biological results sugest that the prepared compounds of interest may act as TcTS enzyme inhibitors and selective cytotoxic agents on tumoral cells.

Les bactéries environnementales font face à de très nombreux stress dans leur milieu devie. Ces dernières doivent s’acclimater rapidement pour faire face à des variations detempérature, des changements d’osmolarité, des changements de pH ou encore descarences nutritives afin de survivre et de prospérer dans leur environnement naturel. Cetravail de thèse s’inscrit dans l’étude de la réponse aux stress chez les bactériesenvironnementales en prenant l’exemple du stress engendré par les métaux chez labactérie modèle Pseudomonas putida et du stress rencontré en cours d’infection deplante chez le phytopathogène Dickeya dadantii. La présence d’un excès d’ionsmétalliques ainsi que les défenses d’une plante sur un phytopathogène entrainent toutdeux un stress oxydatif et peut provoquer une altération membranaire ainsi queprotéique. Ces stress, à première vue éloignés, pourraient ainsi induire des mécanismesde réponses similaires chez les bactéries. La plupart des études de résistance aux stresschez les bactéries portent sur l’étude de gènes sur ou sous exprimés et peuvent alorsmanquer des gènes importants pour la réponse à un stress donné dont l’expressionreste inchangée. Afin d’identifier de nouveaux facteurs de résistance aux stressmétalliques chez P. putida ainsi que de nouveaux facteurs de résistance/virulence chezle phytopathogène D. dadantii, un crible Tn-seq (Transposon-Sequencing) a été réalisé àl’aide de banques de mutants très denses. Les deux cribles ont permis de mettre enévidence le rôle majeur de régulateurs de transcription ainsi que l’importance desmécanismes d’efflux dans la réponse à un stress. Les deux cribles ont aussi mis enévidence l’importance des voies de biosynthèses en acides aminées et acides nucléiques.Enfin, de nombreux gènes à fonction inconnue participent à la survie des deux bactériesen condition de stress. Les résultats obtenus pourraient permettre de développer denouveaux antimicrobiens chez D. dadantii. Les mécanismes de résistance aux métaux etaux antibiotiques peuvent être similaires. Nos travaux améliorent la compréhension desmécanismes de résistance aux métaux et pourraient ainsi permettre de trouver denouvelles molécules à activité antimicrobienne / Environmental bacteria have to deal with a number of stresses in their livingenvironment. The bacteria have to adapt quickly to changes in temperature, osmolarity,pH changes or nutrient deficiencies in order to survive and thrive in their naturalenvironment. This thesis work is related to the study of stress response inenvironmental bacteria by taking the example of stress caused by metals in thebacterium Pseudomonas putida model and stress encountered during plant infection inthe phytopathogen Dickeya dadantii. The presence of an excess of metal ions as well asthe defences of a plant on a phytopathogen both cause oxidative stress and can causemembrane and protein alteration. These stresses, at first sight distant, could thus inducesimilar response mechanisms in bacteria. Most stress resistance studies in bacteriafocus on the study of over- or under-expressed genes and may then lack genesimportant for the response to a given stress whose expression remains unchanged. Inorder to identify new metal stress resistance genes in P. putida and newresistance/virulence factors in D. dadantii phytopathogen, a Tn-seq (Transposon-Sequencing) screen was performed using very dense mutant banks. Both screenshighlighted the major role of transcription regulators as well as the importance of effluxmechanisms in the response to stress. Both screens also highlighted the importance ofamino acid and nucleic acid biosynthesis pathways. Finally, many genes with unknownfunction participate in the survival of both bacteria in stress conditions. The resultsobtained could lead to the development of new antimicrobials in D. dadantii. Themechanisms of resistance to metals and antibiotics may be similar. Our work isimproving our understanding of metal resistance mechanisms and could lead to newmolecules with antimicrobial activity

In Tennessee (TN), the rate of unintended pregnancies remains higher than the national rate (32.4% vs. 30.3%). Although long-acting reversible contraceptives (LARCs) are 99% effective in preventing undesired pregnancies; uptake remains low in rural and underserved communities. Previous research has provided some insight into women’s perceptions of LARCs; however, those guided by conceptual frameworks to understand the multiple influences that impact perceptions towards LARCs, especially among rural regions, are scarce. This multimethod qualitative study explored multiple influences that impact northeast Tennessee women’s perceptions and attitudes toward LARCs using the Socio-ecological Model (SEM) as a guiding framework. The study comprised six focus groups and seven individual interviews of women aged 18-44, not pregnant, and current residents of five counties in Northeast TN. Participants’ demographics were administered through REDCap, while qualitative data from focus groups and interviews were recorded via Zoom. Focus groups and interview data were combined, and an a priori list of codes identified from the constructs of the SEM was initially used to deductively code the data. Subsequently, the data were analyzed inductively for new codes and themes that did not apply to the a priori categories. Seventeen themes and 23 sub-themes were identified using the SEM; On the intrapersonal level of the SEM, participants’ contraception utilization history, attitudes towards a method, perception of method features, and perceived side effects were identified as themes that delineate influences on their LARC utilization. Perception of partner support, perceived support from peer/social networks, and provider trust themes were identified on the interpersonal level. On the community level, the cost of the method, access to information, perceived accessibility to a method, social services, and cultural norms themes were identified. The availability of preferred methods in a clinic, the need for multiple clinic visits to use a method, and provider counseling practices were identified as organizational-level themes. On the policy level, insurance, and billing policies, sex education policies were identified as impacting LARC utilization. Study findings highlight the areas of influence that can be addressed to increase LARC uptake and enable women in rural and underserved regions to achieve their personal reproductive goals.

Les antigènes saccharidiques associés aux tumeurs (TACAs) sont considérés comme des marqueurs de cellules tumorales. Le développement de candidats vaccins synthétiques capables d'induire des réponses immunitaires robustes dirigées contre ces TACAs est un vaste champ d'investigation depuis de nombreuses années. Dans cette optique, mon travail s'est principalement focalisé sur la conception d'un candidat vaccin à trois composantes qui peut activer spécifiquement les cellules dendritiques, les cellules TH et les cellules B. La première partie de la thèse consistait à effectuer une étude approfondie des méthodes submonomère et monomère en solution pour accéder à une plateforme β-tripeptoïde O-α-GalNAc (épitope des cellules B), servant de mime du cluster trimérique de l'antigène Tn (GalNAc-α-O-Ser/Thr). Pour renforcer la stimulation du système immunitaire, un agoniste du récepteur Toll 7 (TLR7) préalablement synthétisé (exprimé par les cellules dendritiques) a été ensuite couplé à cette plateforme par l'intermédiaire de l'acide amino-caproïque, pris comme espaceur. L'édifice candidat vaccin a ensuite été complété par conjugaison au peptide OVA 323-339 (épitope des cellules TH ) grâce à la réaction de cycloaddition 1,3-dipolaire CuAAC. Enfin, l'aptitude du candidat vaccin à induire une réponse anti-Tn a été évaluée par l'équipe du Pr. C. Leclerc de l'Institut Pasteur de Paris. En parallèle de ces études, nous avons mis au point des conditions de ligation multivalente par couplage thiol-ène (TEC) pour l'obtention de peptoïdes S-glycosylés. / Tumor-Associated Carbohydrate Antigen (TACAs) are considered as cancer cells markers. The development of synthetic vaccine candidates which are able to induce a robust immune response against these TACAs is a field of great interest since many years. In this context, my work has been focused mainly on the design of a three-component vaccine candidate with the ability to activate specifically dendritic cells, T H cells and B cells. The first part of the thesis consisted in making a deep study on the submonomer and monomer methods for solution-phase synthesis of a β-tripeptoid O-α-GalNAc scaffold (B epitope). Its role is to mimic the Tn (GalNAc-α-O-Ser/Thr) trimeric cluster which is naturally present on tumor cells surface. To strengthen the stimulation of the immune system, a TLR7 agonist (receptor express by dendritic cells) has been, firstly, coupled through an amino-caproic acid spacer. The vaccine candidate has been next completed by conjugation with the OVA 323- 339 peptide (TH epitope) using the Copper-catalized Alkyne-Azide Cycloaddition (CuAAC). Finally, the capacity of this construction to generate anti-Tn response have been evaluated by the groupe of C. Leclerc of Institut Pasteur of Paris. At the same time, we have also developed conditions for multivalent ligations using thiol-ene coupling (TEC) to obtain a β-tripeptoid S-α-GalNAc scaffolds.

Detta examensarbete har utförts genom ÅF Industry i Trollhättan. Syftet med arbetet är att jämföra två elektriska fördelningssystem i medicinska utrymmen. I sjukhusmiljöer är tillgängligheten av elförsörjning av största vikt. Spänningsbortfall för livsuppehållande utrustning kan få förödande konsekvenser för berörd patient. Svensk standard förespråkar TN-S-system gentemot den europeiska standarden som anser att IT-system är mest lämpligt i dessa utrymmen. Genom att belysa dessa två systems för- och nackdelar kan ett samlat underlag sammanställas som senare används som beslutsunderlag för framtida kunder. Examensarbetet exemplifieras på Östra sjukhuset där befintligt IT-system skall uppgraderas.Skillnaden mellan dessa två fördelningssystem är deras förbindelse med jordpotential. TN-S-system har direkt förbindelse med jord jämfört med IT-system som är helt eller delvis isolerat från jord. Jordfel i TN-S-system kan generera höga felströmmar vilket kan jämföras med IT-system där minimal felström uppstår vid isolationsfel. IT-system och dess isolationsövervakningssystem kan dock anses som mer komplext jämfört med TN-S som är ett vanligare och mer vedertaget fördelningssystem i Sverige.Rapporten konstaterar att IT-system har en stor fördel gentemot TN-S-system. Anledningen är att eventuella jordfelsströmmar i TN-S-system kan bli så pass höga att säkring eller jordfelsbrytare riskerar frånkoppla fördelningssystemet. Denna problematik existerar inte i IT-system då endast små felströmmar uppstår vid isolationsfel. Rekommendationen är att bestycka dessa utrymmen med IT-system med tillhörande isolationsövervakning. Denna tekniska lösning medför tillfredsställande person- och patientsäkerhet med avseende mot elsäkerheten. / This bachelor thesis has been carried out at AF Industry. The purpose of the thesis is to compare two electric distribution systems for medical areas. In medical areas the availability of electric power always has to be maintained. Power failure of life supporting equipment will generate major risks to the patient in question. Swedish standard promotes TN-S-systems compared to the European standard that promotes IT-systems for medical areas. By comparing the advantage and disadvantage of these two systems there can be a complete report compiled, which purpose is to be used to support decision making for future customers. This bachelor thesis will be exemplified in Östra sjukhuset where existing IT-systems will be upgraded.The basic difference between these two electric power systems is their connection to earth. TN-S-systems has direct connection to earth compared to IT-systems that has none or partially connection with earth. Earth fault in TN-systems can generate major current compared to IT-systems where isolations fault generates minimal current. However IT-systems and their isolation monitoring systems might appear as a more complex system compared to TN-S which is a more accepted system in Sweden.The report states that IT-systems has major advantage against TN-systems. The reason is that potential earth fault currents in TN-S-systems might end up disconnecting the fuse or residual current breaker of affected distribution system. This issue doesn't exist in IT-systems where minor fault current is generated from isolation fault. Therefore the recommendation is to equip these medical areas with IT-systems and the associated insulation monitoring systems. This technical solution provides adequate safety for both personal and patients regarding to electrical safety.

This thesis addresses the development, evaluation and modelling of an anti-segregation system ("AS-System") for.use in larger silos handling alumina in the aluminium smelting industry. This work is unlike much of what has gone before because it is much more grounded in the technical and economic consequences of segregation for a particular manufacturing process. Segregation of particulates, i.e. separation of components due to differences in properties such as size, density etc., has an extensive literature going back as far as 1915, but this focuses mainly on the segregation process itself and largely ignores the context and the consequences. The consequence of segregation is loss of homogeneity; the impact that has on any given process, is generally not addressed very deeply. Surveying the literature on segregation, and studying the total processes of aluminium production, creates a basis for understanding the importance of segregation for aluminium production, as well as the importance of powder technology in general for this industry. A method for quantification of segregation in this production process, based on sampling, has been established. This was intended to give the fundamental information necessary for measuring the extent of the problem and the degree of improvement achieved. By placing sampling points along the logistic chain for the alumina, and by sampling these points for a long enough period, information about the influence of the various handling steps on the bulk solids can be identified. Segregation by particle size is the main type of influence, although the work has shown that attrition is another. Standardised statistical expressions have been used for analysing the bottlenecks of the logistic loops, and study of the results has led to a useful way of expressing the level of segregation, the change of segregation level in a handling step (silo filling and discharge), and improvements in this change. The degree of segregation when handling alumina has proven to be quite considerable in terms of effects on the production process. The effects on the efficiency of the aluminium smelting process, and the environment, have both been evaluated. Variations in the alumina due to segregation have been found to correlate with both dust concentration in the smelter pot room, and anode effects (an unwanted upset in the smelting process). An economical evaluation of an investment in anti segregation systems has been made. This evaluation has shown significant economic consequences, clearly justifying both the investigations of segregation, and the implementation of anti segregation measures. To remedy the effects of air current segregation in the aluminium industry, a complete Anti Segregation System (AS-System) based around Anti Segregation Tubes (AST) utilising a special inlet configuration has been developed. In a number of full size installations, this solution has proved itself capable of handling the variations and transients of process conditions which occur in the industry, with a large operational capacity range, due to the special inlet configuration. The effect of the full scale installed anti segregation systems have been measured, and compared to other systems. The AS-System clearly demonstrated a homogenising effect no matter how low the ingoing variations in particle size were. Other commercial systems which have been evaluated have turned out to be no more than Segregation Effect Damping Systems, since they only seem to reduce the segregation effect after it has happened, instead of trying to eliminate the problem by directly attacking the segregation mechanism itself which is what the AS-System does. A new scaled down test rig for the AS-System was developed, consisting of three ASTs fed from a central distributor. To test the potential effect of the AS-System, to determine its efficiency in countering segregation, tests with repeated filling and emptying of a scale silo were carried out. The results clearly showed that the AS-System very much reduced segregation, compared to conventional filling, even in a small-scale silo. Improved models have been developed for the function of the AST and these have been verified against measurements from the new test rig. The early version of the test rig for the AST used only one centre-mounted tube, with one pressure measurement in the top of the tube. The first models were based on the assumption of the pressure being linear, and assumed full dispersion of the falling material inside the tube; and calibrated from the single pressure measurement inside at the top of the tube. Although this simple model calculated very conservative values of the negative pressure, the model was used for the initial development and design of the AST, and later the ASSystem (Anti Segregation System). A second model was derived, where the material velocity was calculated based on free fall. This model was also based on the idea of full dispersion, but was in better agreement with measured values during further tests, which showed a considerable deviation from the original assumption of a linear pressure distribution once intermediate pressure measurements were available. When using the multi-phase-flow-simulation-program-code FLUENT to simulate the pressure distribution of the AST, the results were quite disappointing, however the FLUENT program was able to identify an initial positive pressure generated by the flow from the inlet box to the tube. Implementing this initial pressure into the simple non-linear model above, both the trend and values correspond quite well with the measured values. A single particle drag model was tried, but dismissed after calculating the maximum possible capacity for known tubes and finding the predictions to be unrealistically low. A new approach was introduced, modelling the fall of the powder in a continuous layer along the inner wall of the tube on one side, creating skin drag along the surface between the falling solid powder and the air. The length of the tube and the width of the chosen AST profile define this surface. This approach assumes that the powder falls like a layer along the tube wall. Previous theory for pressure drop in pneumatic conveying inspired this approach, but it had not previously been used for gravity flow in vertical tubes, and as a result the novel Solid Surface Body Drag Model (SSBDM) was developed. This analytical model gives very good correspondence with the measured data for the pressure distribution inside the AST, yet is extremely simple to use. When comparing the model with measured data, the SSBDM was able to predict the pressure distribution within the error boundaries of the test measurements. A method for design of the AST was derived from the SSBDM, using a dimensionless parameter function determined for the pressure drop model. The models giving the design indicate that the capacity is more than proportional to the cross sectional area of a chosen tube profile, which is in agreement with observations. The model suggests that the capacity is proportional to the cross sectional area in the power of 1.25. This model allowed the study of the effect of tube shape, which revealed that a square profile for the AST does not seem to be the optimum design; rather, a rectangular profile should be chosen for maximum capacity. The model suggests that the capacity is proportional to the width of the side of the tube along which the powder layer is falling, but proportional to the perpendicular side in a rectangular profile in the power of 1.5. The model gives an equation for pressure drop which can also be utilised to place the first valve on the tube. It also shows that for high capacities, and large silos, a system consisting of several ASTs should be chosen (AS-System). Predictions from the model have been tested against the measured capacities of full scale installed systems and give good agreement. Overall, the AS-System has been shown to be cost-effective in reducing segregation; results measured from the full scale installations show a homogenising factor (reduction in variation of the material being handled) of 1-1.5. As a result of these verifications and the simplicity of the model presented in this thesis, the plant engineer can confidently design a system which will function correctly and make a positive, predictable improvement in the homogeneity of the alumina in his plant.

Roman military equipment has traditionally been studied from a typological perspective based on a linear concept of change. Whilst Roman alloys have been analysed scientifically and general studies on them have been published, analysis of military equipment has been scarce and mostly secluded as part of excavation reports of individual sites. Scientific analysis though, can provide independent ways of studying military equipment. It can answer questions about production and distribution of the raw materials and finished objects and is capable of informing on reasons for technological choices (the intention of obtaining determinate colours, for example), and identification of military units. A total of 216 copper-alloy military objects from the British sites of South Cadbury Castle, Ham Hill, Usk, Carlisle, Chester and Kingsholm, and the German site of Kalkriese were selected for obtaining metallurgical characterisation: chemical analysis at major, minor and trace element level and microstructural analysis to obtain fabrication history and identifying any plating. The analytical techniques employed were atomic absorption spectrometry (AAS), scanning electron microscopy with energy dispersive x-ray spectrometry (SEM-EDS), optical microscopy and multivariate statistics methods such as principal component analysis (PCA), discriminant analysis (DA) and multivariate analysis of variance (MANOVA). The aim of the project was to characterise the chemical and physical make-up of Roman military copper-alloy metalwork from the 1st century AD, with especial interest in the immediate post-conquest period. The results of the analysis show a difference between the Roman military equipment from British sites and the equipment from Kalkriese, based on trace element patterns. This difference can be explained by a large input of material into Britain that had been made in the years before AD43 in preparation for the conquest. Contrary to recent scholarship, and based on compositional and microstructural evidence, some lorica segmentata brass fittings seem to have been centrally produced. Primary brass and specific gunmetal compositions seem to be associated with the military and probably chosen primarily for their appearance and resemblance to gold, rather than for their mechanical properties. The possibility of mechanised production of brass is explored based on the brass ingot from Sheepen.

The introduction of ceramic matrix composites (CMCs) for structural applications in the hot section of a gas turbine provides many potential benefits over conventional alloy materials, including facilitating elevated operating temperatures. The development of an oxide-oxide CMC composed of commercially available Nextel 720 (3M) fibres within a porous alumina matrix was presented. A simple, low cost processing method involving slurry impregnation and subsequent consolidation and densification was developed, facilitating the production of dried pre-impregnated fabric (‘pre-preg’) that can be stored in ambient conditions. Detailed investigation into the effect of three types of PVA binder, the effect of 0-20wt% additions of an alumina precursor (ACH), the influence of a bimodal particle distribution and the effect of sintering at temperatures between 1100 and 1300°C on processing and mechanical properties was completed in order to optimise the material. The optimised composite material, composed of Nextel 720 fibres within a submicron alumina particle matrix with 10wt% ACH sintered at 1200°C, exhibited mean flexural strength >205MPa, short beam shear strength >12MPa and tensile strength >146MPa. These results were comparable to similar oxide CMCs previously reported, validating this material.

Research has been undertaken to develop new yttria slurry systems for use in mould face coats for investment casting TiAl alloy, solving the pre-gelation problems of commercial yttria slurry systems to increase slurry life. Meanwhile, the new face coats should also have excellent sintering properties, chemical inertness, surface finish and be easy to prepare. The processes of developing the new slurry started with the filler powder investigation by adding different sintering additives into the yttria powder to achieve good sintering properties. Then the best filler powder candidates were selected to make the slurry. Finally, the new face coat slurries were used to make the shell face coat and the chemical inertness of those shells were investigated through the sessile drop and investment casting. In the research, the filler powder and face coat sintering properties were quantified through density, dilatometer testing, X-ray diffraction (XRD) and microstructural change at different testing temperatures. The interaction of different face coat systems and the metal were identified using hardness tests, sessile drop contact angle and the microstructural change at the metal/shell interface. In this research, three water-based binder face coat systems containing YF\(_3\), Y\(_2\)O\(_3\)+0.5wt% Al\(_2\)O\(_3\)+ 0.5 wt% ZrO\(_2\) (YAZ), and B\(_2\)O\(_3\) additives were found to have similar or even better sintering properties compared to a commercial face coat. Meanwhile, they had long life.

Two different Pt-aluminised bond coats, with varying thicknesses and Pt-contents were examined, regarding the in uence of bond coat phases on the oxide growth. This was done in a series of short term (3, 7 and 10 minutes) oxidation experiments at 1100°C. These clearly showed different types of oxide growing on Ni3Al and NiAl phases in the low Pt specimens. It could also be shown that the transition from NiAl to Ni3Al already occurs at these early stages of oxidation. On the high Pt specimens the same types of oxide are growing on Ni3Al and PtAl2. In addition, the high Pt specimens were examined after longer times at temperature (up to 100 hours), to gain information on the bond coat phase transformations happening at high platinum contents. It could be shown that the chromium content plays an important role with regards to phase stability fields in the ternary Ni-Al-Pt diagram. Oxidation kinetics on these samples show that the oxide is not growing at a parabolic rate, but is characterized by a time exponent of 0.145, which may be attributed to a theta to alpha a transformation in the oxide.