Tesis sobre el tema "Masld"

REG3A est un effecteur de l'immunité innée qui joue un rôle important dans l'homéostasie du glucose et qui favorise le maintien d'une flore intestinale commensale aux propriétés anti-inflammatoires. Au cours de notre projet de recherche, nous avons étudié le rôle de REG3A dans le contexte de la maladie métabolique d'origine nutritionnelle et développé pour cela un modèle de maladie métabolique combinant un régime hyperlipidique avec des variations de poids. Les souris C57Bl/6 sauvages et REG3A-TG (exprimant REG3A dans le foie) ont été nourries pendant 1 à 3 cycles avec un régime riche en gras administré en continu ou entrecoupé de périodes d'alimentation standard. Nos résultats montrent que la succession de périodes de gain et de perte de poids favorise le développement d'une MASH chez les souris sauvages, caractérisée par une réduction de la sensibilité à l'insuline, la présence d'inflammation, de ballonnement hépatocytaire et d'une fibrose. L'analyse protéomique des foies révèle que l'alimentation riche en gras augmente le métabolisme lipidique tout en réduisant la voie de biosynthèse du cholestérol. L'expression de REG3A réduit l'hépatopathie inflammatoire et le développement de fibrose chez la souris, réduction qui est corrélée à l'activation de la voie de signalisation de l'IFN-γ/STAT1. L'alimentation hyperlipidique induit chez la souris sauvage le remodelage de la matrice extracellulaire du foie et cela, bien en amont de l'apparition de la fibrose, matrice inflammatoire remodelée qui altère la capacité d'hépatocytes en culture primaire de répondre à l'insuline. L'expression de REG3A impacte également sur la composition de cette matrice inflammatoire qui préserve alors sa capacité à sensibiliser les hépatocytes à répondre à l'insuline. En conclusion, nos travaux révèlent les effets pervers de l'alternance de périodes de gain et perte de poids chez la souris (régime yo-yo) qui favorise la sévérité de la maladie métabolique du foie d'origine nutritionnelle et le rôle protecteur que joue l'effecteur de l'immunité innée REG3A dans cette maladie
REG3A is an effector of innate immunity which plays an important role in glucose homeostasis and promotes the maintenance of a commensal gut flora with anti-inflammatory properties. In our research project, we investigated the role of REG3A in the context of nutritionally-induced metabolic disease, using a metabolic disease model combining a hyperlipidic diet with weight cycling. Wild-type C57Bl/6 and REG3A-TG mice (expressing REG3A in the liver) were fed with a high-fat diet for 1-3 cycles, either continuously or interspersed with standard feeding periods. Our results show that successive periods of weight gain and loss promote the development of MASH in wild-type mice, characterized by reduced insulin sensitivity, inflammation, hepatocyte ballooning and fibrosis. Proteomic analysis of livers reveals that high-fat diet increases lipid metabolism in mice while reducing the cholesterol biosynthesis pathway. REG3A expression reduces inflammatory hepatopathy and fibrosis development in mice, a reduction that correlates with activation of the IFN-γ/STAT1 signaling pathway. In wild-type mice, hyperlipidic feeding induces remodeling of the extracellular matrix in the liver, well before the onset of fibrosis. This remodelled inflammatory matrix impairs the ability of primary cultured hepatocytes to respond to insulin. REG3A expression also has an impact on the composition of this inflammatory matrix, which then preserves its ability to sensitize hepatocytes to respond to insulin. In conclusion, our work reveals the perverse effects of alternating periods of weight gain and loss in mice (yo-yo diet), which promotes the severity of nutritionally induced metabolic liver disease, and the protective role played by the innate immune effector REG3A in this disease

MASL PROPOSE UNE APPROCHE UNIFIEE ET MACROSCOPIQUE A L'EXPRESSION DE CALCULS HETEROGENES ET DISTRIBUES SUR DES AGENTS CONÇUS EN SUIVANT LE MODELE DELIBERATIF, REACTIF OU HYBRIDE. C'EST UN LANGAGE DE HAUT NIVEAU INDEPENDANT DE L'EXECUTIF OU CHAQUE AGENT, VU COMME UNE ENTITE CONCURRENTE, DETERMINE LOCALEMENT SA PARTICIPATION A DES BLOCS D'EXECUTION COLLECTIFS (E-BLOCS). CHAQUE E-BLOC EST UN PROGRAMME COLLECTIF ANONYME POUVANT S'EXECUTER SUR UN RESEAU D'AGENTS SELON DES CRITERES LOCAUX. LE MODE D'ORCHESTRATION (SCALAIRE, SYNCHRONE, ASYNCHRONE) EST DETERMINE STATIQUEMENT PAR UN ATTRIBUT DU BLOC, LES COMMUNICATIONS SUPPORTENT LE MODELE A MEMOIRE PARTAGEE, LE MODELE A ENVOI DE MESSAGES ET LE MODELE D'EVENEMENTS. L'HETEROGENEITE DES AGENTS EST ASSUREE PAR HERITAGE ET POLYMORPHISME ALORS QUE L'AUTONOMIE EST PROPOSEE PAR UN MECANISME (APPELE PERMEABILITE) DE FILTRAGE OU CHAQUE AGENT PEUT MASQUER/OUVRIR SON INTERFACE DYNAMIQUEMENT ET SELON LA POSITION DE L'EMETTEUR DANS LA HIERARCHIE D'E-BLOCS. DANS UN CONTEXTE D'ALLOCATION DYNAMIQUE DES AGENTS, DE REPRISE APRES ECHEC OU DE REMPLACEMENT D'UN AGENT ROBOTIQUE DANS UNE FLOTTE DE ROBOTS (CAS D'UNE PANNE OU PERTE DE FONCTIONNALITE COMPROMETTANT LA MISSION), LE E-BLOC PROPOSE UNE PERSPECTIVE DE POINT D'ENTREE D'UN TRAITEMENT COLLECTIF. DANS LE CAS D'E-BLOC SYNCHRONES, LE PARADIGME SOUS-JACENT EST ISSU DU MODELE DATA-PARALLELE, PERMETTANT ICI DES TRAITEMENTS ITERATIFS PAR VAGUES SUCCESSIVES D'AGENTS. AU FINAL, MASL PROPOSE DES AVANCEES DANS LE DOMAINE DES SMA (APPARTENANCE DYNAMIQUE A DES GROUPES, PRECISION DU RYTHME DES ACTIONS A ENTREPRENDRE POUR PERMETTRE UNE COOPERATION DESIREE) ET AU NIVEAU DE LA GESTION DES ERREURS.

L'approche classique des langages pour le contrôle de Systèmes Multi-Agents (SMA), a fortiori robotiques et autonomes, consiste d'abord en un point de vue microscopique : chaque agent dispose de son propre programme de contrôle contenant des primitives de communication / synchronisation permettant la coopération / collaboration entre agents. L'émergence d'un comportement global, le point de vue macroscopique du calcul, ne peut qu'être observé a posteriori. Dans ce contexte, MASL propose une approche unifiée et macroscopique à l'expression de calculs hétérogènes et distribués sur des agents conçus en suivant le modèle délibératif, réactif ou hybride. C'est un langage de haut niveau indépendant de l'exécutif où chaque agent, vu comme une entité concurrente, détermine localement sa participation à des blocs d'exécution collectifs (e-blocs). Chaque e-bloc est un programme collectif anonyme pouvant s'exécuter sur un réseau d'agents selon des critères locaux. Le mode d'orchestration (scalaire, synchrone, asynchrone) est déterminé statiquement par un attribut du bloc, les communications supportent le modèle à mémoire partagée, le modèle à envoi de messages et le modèle d'évènements. L'hétérogénéité des agents est assurée par héritage et polymorphisme alors que l'autonomie est proposée par un mécanisme (appelé perméabilité) de filtrage où chaque agent peut masquer/ouvrir son interface dynamiquement et selon la position de l'émetteur dans la hiérarchie d'e-blocs. Dans un contexte d'allocation dynamique des agents, de reprise après échec ou de remplacement d'un agent robotique dans une flotte de robots (cas d'une panne ou perte de fonctionnalité compromettant la mission), le ebloc propose une perspective de point d'entrée d'un traitement collectif. Dans le cas d'e-bloc synchrones, le paradigme sous-jacent est issu du modèle data-parallèle, permettant ici des traitements itératifs par vagues successives d'agents. Au final, MASL propose des avancées dans le domaine des SMA (appartenance dynamique à des groupes, précision du rythme des actions à entreprendre pour permettre une coopération désirée) et au niveau de la gestion des erreurs
The classical approach for Multi-Agent System (MAS) Control, especially autonomous and robotic ones, deals first from a microscopic point of view: each agent embed a control program with communication/synchronization primitives that enable cooperation between agents. The emergence of a global behaviour from a macroscopic point of view can only be observed afterwards. In this context, MASL offers a macroscopic and unified approach with heterogeneous and distributed calculations over deliberative, reactive or hybrid agents. In this high level language, regardless of the runtime, each concurrent agent locally decides its participation in a collective execution block named an e-block. Each e-block is an anonymous collective program that runs over an agent network following local conditions. The orchestral mode (scalar, asynchronous, synchronous) is statically fixed by a shared block attribute. The communication use shared memory, events, synchronous messages passing, and asynchronous messages passing. Heterogeneous agents are managed with heritage and polymorphism. Permeability mechanism, dealing with agent autonomy, allows an agent to dynamically filter calls to its interface in respects to the sender position in the e-block hierarchy. In dynamic task allocation of agents, auto failover and recovery, agent replacement in a robot fleet (case of agent failure, loss of a mandatory functionality for the mission) an e-block is an entry point of a collaborative work. In the case of synchronous e-block, the programming paradigm is the data parallel model with iterative task for waves of agents. Finally, MASL offers advances in the field of MAS (dynamic belonging to groups, accuracy of the pace of actions to undertake to enable a desired cooperation) and for the management of errors

The findings from chronic complex diseases modelled in animals are difficult to extrapolate to humans. In metabolic (dysfunction) associated fatty liver disease (MAFLD), dietary models are commonly used to study the mechanisms for disease progression. The current dogma is that diets rich in fat, simple carbohydrates, and cholesterol can lead to systemic alterations in metabolism that leads to the accumulation of lipids in the adipose and liver tissues. This leads to lipotoxicity and a vicious cycle of inflammation and liver injury which can drive disease progression. Hence, there has been a considerable interest to model and comprehend the role of metabolism and the immune response in this disease. However, our knowledge of the underlying mechanisms in MAFLD is still limited. A major caveat is that pre-clinical models do not represent the full spectrum of human diseases. This has been a major source of failure in clinical trials. Understanding the impact of dietary challenges in animal models and where they resemble or diverge from human disease can help to resolve the current dilemmas that have hampered progress in the field. In this thesis, I used different dietary models in mice and characterised liver pathology, the liver immune profile, and the landscape of liver gene expression. Initially, we used multiple dietary models containing simple (sucrose) or complex carbohydrates, with/without cholesterol (2%), and with/without an added bile acid (cholic acid): A) normal chow (NC); B) high sucrose (HS); C) high sucrose and high cholesterol (HS_Chol2%); D) high sucrose, high cholesterol (2%) and cholic acid (HS_Chol2%_CA); E) high cholesterol (2%) and cholic acid (Chol2%_CA); F) cholic acid (CA). From a liver pathology perspective, diets containing cholesterol (Diets C to E) induced a dramatic change in liver pathology. Consistently, immune profiling of the liver of mice fed these diets induced infiltration of a broad range of immune cells including myeloid and lymphoid cells (diets C to E). Of note, the combination of cholesterol and cholate (diets D and E) had synergistic effects and dramatically enhanced liver immune cell infiltration. Subsequently, we performed RNA sequencing on the liver of mice fed these 6 diets. In agreement, we detected the highest differentially expressed genes in diets containing cholesterol and cholate (diets D and E). We conclude that this combination disturbs liver homeostatic functions the greatest. To gain a systems perspective of perturbations in liver homeostatic function, we undertook a systems approach and applied weighted gene co-expression network analysis (WGCNA) on liver transcriptomes. We noticed several gene expression modules (networks) that were associated with diets. Most of these modules were enriched for metabolic pathways and immune responses. Of interest, there was a negative correlation between immune and metabolic-related modules. This was reminiscent of immunometabolism and a co-variance in gene regulatory networks between metabolic and immune modules. The up-regulation of immune responses and down-regulation of metabolic networks within the liver were prominent in mice exposed to cholesterol and cholate. A published report and our unpublished data (not the subject of this thesis) indicated that diets containing cholesterol and cholate induce a heightened immune response with anti-tumorigenic properties. Thus, from a phenotypic perspective, this immune response and the outcomes are divergent from human fatty liver that increases the risk of liver cancer. One caveat in our dietary models was that they contained supra-physiological levels of cholesterol (2%). I detected a suppression in the expression of genes in cholesterol biosynthesis pathway in all diets that contained cholesterol (Diet C) or cholic acid (Diets D to F). This was in contrast with a study on clinical fatty liver disease (in humans) which reported up-regulation of genes in cholesterol biosynthesis pathways. I hypothesised that reduction in cholesterol biosynthesis could be related to a higher immune response. Hence, I omitted cholic acid and reduced the amount of cholesterol to 0.2% and investigated the liver pathology in mice exposed to a HS_Chol0.2% diet. This diet also induced minimal liver pathology similar to the HS diet. Despite a reduction in the cholesterol content, I detected a suppression in the expression of genes in cholesterol biosynthesis in mice exposed to the 0.2% cholesterol in the diet. This indicates a diverged response in cholesterol metabolism between mice and human liver. This diet did not induce pathological features resembling human MAFLD, however it resembled some characteristics of metabolic syndrome such as adiposity with systemic glucose intolerance. One of the models that is often used to simulate MAFLD is the MCD (methionine choline deficient) diet. This diet induced pathological features resembling human MAFLD, however, our analysis of liver transcriptome data on mice fed with MCD diet indicated down-regulation in metabolic pathways and cholesterol biosynthesis. Indeed, the behaviour of these modules in mice on the MCD diet resembles those in mice exposed to high levels of cholesterol, which are divergent from human fatty liver disease. Overall, my results have shown that mice dietary models do not fully resemble clinical fatty liver either phenotypically or at the gene expression level. A possible strategy to overcome these limitations is to use multiple models in which each model could represent a specific aspect of the disease. At the molecular level, undertaking a module-based approach to understand the link between the behaviour of preserved modules (e.g., between mice and humans) to phenotypic outcome is an alternative strategy. One unmet need in human fatty liver is dissociating liver tissue inflammation from protective immune responses (immunosurveillance), which I would like to delve into in my future endeavours.

Background: Metabolic associated fatty liver disease (MAFLD) afflicts about a quarter of the global population. A proportion of these patients develop chronic inflammation which can progress to cirrhosis and cancer. Sugar consumption is a major risk factor of MAFLD progression and a human FGF21 variant (rs838133) was recently found to be a risk variant for increased sugar consumption. Whether this variant is a novel risk factor for MAFLD is unknown. Methods: We studied the association of FGF21 rs838133 with liver disease severity and the metabolic profile of patients with MAFLD. Functional investigations were undertaken using allele-specific expression of FGF21 in liver, by measurement of serum FGF21 by ELIZA, bioinformatics analysis and by complementary mouse studies. Results: FGF21 rs838133 was associated with an increased risk of metabolic associated steatohepatitis (MASH), but not simple steatosis. The variant did not affect hepatic FGF21 expression or splicing, but likely affects FGF21 mRNA structure. Compared to healthy controls, patients with MAFLD have higher serum FGF21 levels (p < 0.05). This difference was more profound in patients with MASH (162 ± 47.26, p < 0.01) compared to those with simple steatosis (155.2 ± 51.98, p < 0.01). Similarly, FGF21 levels increased with progression of the NAS score and with fibrosis (p <0.05, for both). Consistently, there was a positive correlation between FGF21 levels and blood glucose, HOMA-IR, AST, GGT, triglycerides, total bile acids and primary bile acids (p < 0.05, for all). In mouse models of liver injury, Fgf21 expression was increased by a high sucrose diet, and in two liver injury models, namely bile duct ligation (p < 0.05, for both) and a methionine and choline deficient diet (p < 0.0001). There was no correlation between serum levels of FGF21 and other FGF family proteins (FGF19, FGF23). Conclusion: FGF21 rs838133 is a novel risk variant for MASH, likely via a change in mRNA folding and subsequently, stability. FGF21 serum levels are likely increased in MASH due to hepatic resistance and correlates with markers of glycaemic profile and bile acids in these patients. Different members of the FGF family of proteins are likely regulated by different mechanisms.

Background: Fibroblast growth factor 21 (FGF21) is a liver-derived hormone with pleiotropic beneficial effects on metabolism. Paradoxically, FGF21 levels are elevated in metabolic diseases. Interventions that restore metabolic homeostasis reduce FGF21. Whether abnormalities in FGF21 secretion or resistance in peripheral tissues is the initiating factor in altering FGF21 levels and function in humans is unknown. Methods: I have studied the role of the rs838133 polymorphism in regulating FGF21 protein expression in-vivo and in-vitro. Then, I explored the mechanisms by which this single nucleotide polymorphism (SNP) modulates FGF21 production. I utilized RiboLace methodology to examine FGF21 production associated with the ribosomal translationally active fraction. Next I developed an in-vitro genetic model to help resolve the paradox of FGF21 expression in metabolic disorders. Furthermore, I studied the association between rs838133 and the expression of FGF21 receptors and activity. Finally, I related my findings back to tissue and explored the functional impact of rs838133 on hepatic inflammation. Results: I have shown that the minor (A) allele of the rs838133 polymorphism is associated with higher levels of circulating and hepatic FGF21 and it is not associated with the expression of fibroblast growth factor receptor 1 (FGFR1), Klotho-β (KLB) nor fibroblast activation protein (FAP) and hence and does not alter FGF21 signalling or activity. Then I identified an unanticipated mechanism for the FGF21 levels variation which is a genotype dependant alteration in the translational rate of FGF21. This alteration is most probably the primary event which results in FGF21 levels disturbance. Furthermore, I have demonstrated that codon bias and secondary mRNA structure are pivotal elements of the effect of rs838133 on the FGF21 translation rate. Additionally, I have proposed that ribosomal protein lateral stalk subunit P0 (RPLP0) could be the link between metabolic stress and FGF21 overexpression in metabolic disorders. Finally, I have related my results back to tissue and identified that under metabolic stress, the rs838133 has a deferential inflammatory response in-vivo and in-vitro. Conclusion: My results highlight a dominant role for translation of the FGF21 protein to explain variations in blood levels that is at least partially inherited. These results provide a framework for translational reprogramming of FGF21 to treat metabolic diseases.

Les spectres de diffusion RAMAN et d'absorption Infrarouge des hydrures double d'aluminium et d'un métal alcalin MAlH₄ (M =Li, Na) et de leurs homologues deutériés MAlD₄ ont été enregistrés. Les techniques d'échantillonnage ont été optimisées afin d'obtenir les spectres RAMAN de ces -composés extrêmement sensibles à l'air. Un mini cryostat à température variable a été mis au point pour étudier ces échantillons de 100 à 400 K. Pour NaAlH₄, les modes de réseau ont été observés pour la première fois. L’application de la théorie des groupes a permis l’analyse vibrationnelle complète de ce cristal et a conduit à attribuer les fréquences de diffusion RAMAN aux modes de vibration du solide. Les résultats obtenus confirment le caractère ionique du cristal. Les spectres de diffusion RAMAN de LiAlH₄ et LiAlD₄, dans leur phase à pression atmosphérique (a), ont été enregistrés et les modes de réseau ont été aussi observés. Malgré 1’absence de données cristallographiques précises, une analyse vibrationnelle dé ces solides a été menée et la plupart des fréquences ont été attribuées. Une nouvelle phase a a été mise en évidence pour LiAlD₄. Les spectres RAMAN de cette phase ont été enregistrés et étudiés. La transformation irréversible LiAlD₄₋α' -> LiAlD₄-α par élévation de T, a été confirmée et observée à environ 65°C. Les spectres RAMAN de LiAlD₄-α et LiAlH dans leur phase haute pression (ɣ) ont enfin été enregistrés. L'analyse des spectres montre que, pour ces composés, l'aluminium possède une coordinence intermédiaire entre 4 et 6, proche de la structure des hydrures M₃AlH₆

Background: Toll-like receptors (TLRs) are important mediators of inflammatory pathways which play a major role in initiating immune responses. The breakdown of TLR tolerance results in development of liver disease including metabolic (dysfunction) associated fatty liver disease (MAFLD) and COVID-19. Membrane bound O-acyltransferase domain containing 7 (MBOAT7) is a phospholipid modifying enzyme highly expressed in both liver and macrophages. This study reports a novel role of MBOAT7 in MAFLD, through the regulation of TLR receptor signalling. Methods: I have studied the role of MBOAT7 in regulating TLRs- induced outcomes in human monocyte-derived macrophages from healthy subjects and those with MAFLD. Then, I explored the mechanisms by which this single nucleotide polymorphism (SNP) regulates the negative correlation between MBOAT7 and TLRs induced outcomes. Functional investigations were undertaken using two approaches namely MBOAT knockdown or overexpression were used followed by TLRs agonists stimulation. Results: MBOAT7 is a crucial negative regulator of TLR signalling. MBOAT7 deficiency in macrophages as observed in patients with MAFLD and in COVID-19, alters membrane phospholipid composition. I demonstrate that this is associated with a redistribution of arachidonic acid toward proinflammatory eicosanoids, induction of endoplasmic reticulum stress, mitochondrial dysfunction, and remodelling of the accessible inflammatory-related chromatin landscape culminating in macrophage inflammatory responses to TLRs. Activation of MBOAT7 reverses these effects. These outcomes are further modulated by the MBOAT7 rs8736 (T) MAFLD risk variant. Conclusion: My results define a critical role for MBOAT7 in processes crucial for systemic immune homeostasis, including for a broad range of TLR responses. These findings suggest that MBOAT7 can be exploited as a therapeutic target for diseases associated with dysregulation of the TLR signalling cascade

This degree project was performed at M-real Technology Centre in Örnsköldsvik. The perpose was to investigate thedifferences in gloss and gloss variations between chemical and ground toner and different paper grades in electrophotographicprints. Gloss is a property that gives the impression of a higher quality of a product. Therefore it is of great importance toaccomplish high gloss in advertising print.A test chart was printed on three different uncoated paper grades on three different printers. Thereafter, gloss, glossvariation, surface topography, print mottle and density were measured. A visual evalution was also performed. A multivariateanalysis was acheived of the data in order to find correlations between the measured variations.The results showed that paper grades with large surface roughness gave more variations in surface topography and glossvariations (both visual and measured) in print. A rough surface also gave more print mottle. Ground toner gave moresurface topography variations and mottle which increased with the amount of silicone used.

Aims: This thesis aimed to examine the efficacy of exercise to reduce liver fat firstly via meta-analysis and then through investigation of a novel exercise modality; low volume high intensity interval training with combined progressive resistance training. This thesis also investigates circulating immune markers in adults with obesity and either normal glucose (NG) or prediabetes, and the effects of a novel exercise intervention. Results: The meta-analysis found that exercise was able to reduce liver fat by -2.4%, -3.13 to -1.66 (mean, 95% CI). In this randomised control trial study, people with prediabetes had increased liver fat compared to NG (absolute % liver fat in prediabetes: 11.4 ± 1.7, in NG: 5.2 ± 1.1, p= 0.002) despite having similar BMI at baseline. In a RCT involving a subgroup only of those in the PACE-G study, the exercise intervention (NG n=37, Prediabetes n=31), vs sham (NG n=39, Prediabetes n=29), showed a small effect on liver fat, which was not statistically significant when compared with control (NG exercise vs control: -0.7±0.7%, prediabetes exercise vs control: -1.2±0.9%). With respect to circulating cytokines IL-8 was significantly higher in NG than prediabetes and IL-15 and IL-22 were higher in prediabetes than NG. Interestingly, adults with prediabetes who undertook the exercise intervention did not realise the same reduction in pro-inflammatory cytokines as adults with NG. Finally, adults with prediabetes had reduced circulating angiogenic CD8+ T cells. Adults who undertook the exercise intervention improved circulating angiogenic T cells. Conclusions: The work in this thesis shows that while only some types of exercise may improve metabolism and liver fat and novel CV risk markers may still be improved by certain exercise regimens even when metabolism is not overtly improved.

De change, les flux commerciaux ou commerces et la croissance économique de Madagascar. En d’autres termes nous avons étudié les effets de la volatilité et le mésalignement du taux de change sur les exportations, les importations, et la croissance économique. Pour pouvoir réaliser cette étude, nous avons utilisé des données annuelles entre la période 1971-2012 pour les exportations et importations globales, et la période 1990-2011 pour les exportations et importations par secteur. Nous avons mesuré la volatilité à l’aide de deux méthodes, et nous avons obtenu la volatilité par l’écart-type mobile et la volatilité calculée par le GARCH. La méthode de cointégration a été utilisée pour l’étude des variables. Avec le modèle NATREX, le mésalignement a été calculé comme la différence du TCER à l’instant t et TCER d’équilibre. Sur la dernière partie du travail et afin de répondre à notre problématique, nous faisons appel à la méthode SUR (Seemingly Unrelated Regression). Cette méthode nous a permis d’estimer notre modèle à deux equations pour les exportations en volume et les importations en volume. En bref, pour le cas Madagascar, d’une part en considérant l’exportation, le mésalignenemt a un impact positif significatif sur l’exportation globale quelle que soit la définition de la volatilité, en effet la sur-évaluation de l’Ariary augmente l’exportation. Par ailleurs, la volatilité a un impact positif significatif sur l’exportation globale uniquement avec la prise en compte du VOLGARCHTCEN. D’autre part en considérant l’importation, le mésalignenemt a un impact positif significatif sur l’importation globale avec la prise en compte du VOLMASDTCER, et du VOLMASDTCEN, la sur-évaluation de l’Ariary augmente l’importation. La volatilité a un impact positif significatif sur l’importation pour les trois cas suivants : VOLMASDTCEN, VOLGARCHTCER, VOLGARCHTCEN. Avec l’exportation globale ou l’importation globale, le mésalignement n’a pas d’impact significatif sur le taux de croissance, par contre la volatilité a un impact négatif significatif sur le taux de croissance en considérant le VOLMASDTCER, et le VOLMASDTCEN
In this thesis, we tried to know the relationship between the variability of exchange rates, trade flows and economic growth in Madagascar. In other words, we have studied the effects of volatility and misalignment of the exchange rate on exports, imports, and economic growth. To conduct this study, we used annual data from the 1971-2012 period for global exports and imports, and the 1990-2011 period for exports and imports by sector. We measured the volatility using two methods, and we got the volatility by moving standard deviation and volatility calculated by the GARCH. The method of cointegration was used to study the variables. With NATREX model, the misalignment was calculated as the difference between REER at time t and REER equilibrium. On the last part of this work and to resolve our problem, we use the method SUR (Seemingly Unrelated Regression). This method allowed us to estimate our model with two equations for export volumes and import volumes.Finally, the results show that for the case of Madagascar, considering exports, misalignment has a significant positive impact on overall export whatever the definition of volatility, indeed over-evaluation increases export. Then, volatility has a significant positive impact on overall export only with the inclusion of VOLGARCHTCEN. Moreover considering imports, misalignment has a significant positive impact on the overall import with the inclusion of VOLMASDTCER, and VOLMASDTCEN, over-evaluation increases import. The volatility has a significant positive impact on the import in the case of : VOLMASDTCEN, VOLGARCHTCER, VOLGARCHTCEN. With the global export or import, misalignment has no significant impact on the growth rate, however volatility has a significant negative impact on growth rates considering VOLMASDTCER, and VOLMASDTCEN

The following thesis is a comparison study which was performed in cooperation with Sika Sverige AB. The project was to examine concrete’s behaviour while being subjected to different accelerators which is used to speed up the hardening process in young concrete. Sika provided the materials and the instructions for the tests that were made. The tests used where almost like the tests being performed at Sika’s laboratories but with some adjustments to the testing equipment. According to the results of the tests a clear difference between the different accelerators were found. The conclusion that the efficiency of the different accelerators were affected on several variables such as cement type, hardening age and hardening temperature were drawn. Because of the corona outbreak (2020) the tests could not be performed in Sikas laboratories. The tests were therefore carried out at a temporary laboratory without any direct supervision and some professional equipment could not be obtained which resulted in replacements with creative solutions. These changes affected the individual test results with high certainty but should not interfere with the conclusions on account that all test samples were subjected to the same circumstances.

In 2017, the Swedish Parliament stated a new climate law with the goal that Sweden should be climate neutral by 2045. The concrete industry has developed a roadmap on how the goal for 2045 can be achieved, where one way to reduce the carbon emissions from concrete is by replacing a part of the cement clinker with alternative binders in the concrete mix. Ground granulated blast furnace slag (GGBS), fly ash, silica fume and trass are alternative binders that are possible to use in concrete mixes to reduce the amount of ordinary Portland cement (OPC). GGBS, fly ash and silica fume are by-products from other industries, while trass is volcanic ash that can be extracted. Besides the positive environmental impact that comes from using alternative binders and reducing the amount of cement clinker, the alternative binders have other properties, both positive and negative, that affect the concrete. The aim of this thesis was to investigate whether concrete with alternative binders does fulfill the regulations set by Swedish standards and how concrete with alternative binders does affect the material parameters. The concrete mixes were divided into three different types of concrete: concrete for bridges (w/c ratio 0.4), hydropower structures (w/c ratio 0.45) and wind powerplant foundations (w/c ratio 0.55). A total of seven concrete mixes were cast in a laboratory and the concrete mixes were investigated in the three hardening stages of concrete: fresh, young and hardened. The analyzed material parameters were compressive strength, shrinkage, frost resistance, workability, air voids and temperature development. Beyond the experimental testing, a global warming potential (GWP) comparison was made to compare the reduction of GWP for each concrete mix compared to a reference concrete for each usage area. The mix containing a CEM II/A-V fly ash cement and 15% GGBS showed great potential regarding the different material parameters. This mix, however, is according to Swedish standards not possible to certify for structures in exposure class XF4, such as bridges, but is possible to certify for structures in exposure class XF3, such as wind powerplant foundations. The mix containing 30% GGBS and 5% silica fume also showed beneficiary properties, but superplasticizers are required in this mix to ensure good workability. For hydropower structures, the mix containing 35% GGBS showed a great compressive strength but a high temperature development and low workability. The mix containing trass had a notably low temperature development, but with an increase in shrinkage and low workability. Moreover, all concrete mixes showed a frost resistance which, according to standard, is classified as “Very Good”.
Sveriges regering antog 2017 ett nytt klimatpolitiskt ramverk med målet att Sverige ska ha noll nettoutsläpp av växthusgaser år 2045. Betongindustrin har tagit fram en färdplan för hur betong kan bli klimatneutralt, där ett sätt att reducera klimatpåverkan från betong är att byta ut en del av cementklinkern mot alternativa bindemedel. Mald granulerad masugnsslagg (GGBS), flygaska, silikastoft och trass är alternativa bindemedel som är möjliga att använda i betongblandningar för att reducera mängden Portlandcement. GGBS, flygaska och silikastoft är restprodukter från andra industrier medan trass är en vulkanisk aska som kan utvinnas. Utöver den positiva miljöeffekten som erhålls när alternativa bindemedel ersätter cementklinker, så har de alternativa bindemedlen andra egenskaper, både positiva och negativa, som påverkar betongen. Målet med denna studie var att undersöka och jämföra om betongblandningar där en del av cementklinkern har ersatts med alternativa bindemedel når upp till de krav som ställs i nuvarande regelverk. Utöver det så undersöktes även hur betongblandningarnas materialparametrar påverkades av alternativa bindemedel. Betongblandningarna delades in i tre olika typer av betong: betong för broar (vct 0.4), vattenbyggnader (vct 0.45) och vindkraftverksfundament (vct 0.55), där totalt sju betongblandningar tillverkades i ett laboratorium. Betongblandningarna undersöktes i de tre olika faserna för hårdnande av betong, vilka är färsk, ung och hårdnad betong. De materialparametrar som analyserades var tryckhållfasthet, krympning, frostresistens, arbetbarhet, luftporhalt och temperaturutveckling. Förutom de experimentella testerna gjordes en jämförelse kring hur mycket koldioxid som kan reduceras för varje betongblandning, jämfört med en referensbetong för varje användningsområde. Betongblandningen med ett CEM II/A-V flygaska-cement och 15% GGBS visade stor potential med avseende på de olika materialparametrarna. Denna blandning är dock enligt svensk standard inte möjlig att certifiera för betongbyggnad i exponeringsklass XF4, exempelvis broar, men kan certifieras för betongbyggnad i exponeringsklass XF3, exempelvis fundament för vindkraftverk. Blandningen med 30% GGBS och 5% silikastoft visade även positiva egenskaper, men flyttillsatsmedel måste användas i denna blandning för att erhålla en god arbetbarhet. För vattenbyggnadsbetong så visade blandningen med 35% GGBS en hög tryckhållfasthet, men samtidigt en hög temperaturutveckling och en låg arbetbarhet. Blandningen med trass hade en noterbart låg temperaturutveckling, men med ökad krympning samt låg arbetbarhet. Avslutningsvis så uppvisade alla blandningar en frostresistens som enligt standard klassificeras som ”Mycket bra”.

Stockholm Vatten has decided to close down the Bromma waste water treatment plantand manage the waste water from Bromma together with the waste water from the formerEolshällsverket to Henriksdal’s waste water treatment plant. Henriksdals wastewater treatment plant will be expanded for higher purification requirements and loads,estimated to be finished until 2040. This entails extensive renovations and additionsto the existing treatment plant in and on Henriksdalsberget, as well as a major expansionof the Sickla plant.The purpose of the study is to investigate an environmentally friendly alternative tothe standard concrete that will be used for the expansion of the Sickla plant. The largestenvironmental villain in concrete is the cement. The aim of this study has beento replace the cement with environmentally friendly additives in the largest possibleamount, thus reducing the negative impact of the cement on the environment.In the present study, a review was made of obtained data with exposure classes, then aliterature study was performed to gain knowledge in the area. With help from experts,two fictitious recipes for each exposure class have been calculated for the standardconcrete and the green concrete. In this way, a careful comparison between the concretetypes was made of the cement’s impact on global warming. Thereafter, a study wascarried out on existing EPDs, which were incorporated into the One Click LCA (2015)software. An LCA in the mentioned software was carried out, which enabled data to becompiled and a comparison of the climate impact between the four different fictitiousrecipes has been done.Compiled and compared data from LCA and analysis of EPDs show that 70% of thestructure with exposure class XD2 gets a 47% reduction in global warming when usinggreen concrete instead of standard concrete. Furthermore, the results show that theremaining 30% of the structure with exposure class XF3/XC4 gets a 20% reductionwhen using green concrete instead of standard concrete. The total reduction in globalwarming when using green concrete instead of standard concrete for the expansion ofSickla treatment plant was calculated to be 40%.
Stockholm Vatten har beslutat att lägga ned Bromma reningsverk och leda avloppsvattnetfrån Bromma tillsammans med avloppsvattnet från det forna Eolshällsverkettill Henriksdals reningsverk. Henriksdals reningsverk ska byggas ut för högre reningskravoch belastningar beräknade till år 2040. Detta medför omfattande om- och tillbyggnationeri det befintliga reningsverket i och på Henriksdalsberget samt en storutbyggnad av Sicklaanläggningen.Syftet med detta arbete är att undersöka ett miljövänligare alternativ till standardbetongensom ska användas vid utbyggnaden av Sicklaanläggningen. Då den främsta”miljöboven” i betongen är cementet har målet med denna studie varit att ersätta cementetmed miljövänliga tillsatsmaterial i största möjliga mängd, i syfte att minskacementets negativa inverkan på miljön.I föreliggande arbete har en genomgång utförts på erhållna data med exponeringsklasser,därefter påbörjades en litteraturstudie i syfte att inhämta kunskaper inomområdet. Med hjälp av experter har två fiktiva recept för respektive exponeringsklassräknats fram för standardbetongen och den gröna betongen. Med denna metod genomfördesen noggrann jämförelse mellan de olika recepten avseende cementets inverkanpå den globala uppvärmningen. Därefter undersöktes existerande EPD:er, vilka infogadesin i programvaran One Click LCA (2015). En LCA i den nämnda programvaranutfördes, vilket möjliggjorde att data kunde sammanställas och en jämförelse av klimatpåverkanmellan de fyra olika fiktiva recepten kunde genomföras.Sammanställd och jämförd data från LCA och analys av EPD:er visar att 70% av konstruktionenmed exponeringsklass XD2 får en reducering på 47% på den globala uppvärmningenvid användning av grön betong istället för standardbetong. Vidare visarresultatet att resterande 30% av konstruktionen med exponeringsklass XF3/XC4 fåren reduktion på 20% vid användning av grön betong istället för standardbetong. Dentotala reduktionen på den globala uppvärmningen vid användning av grön betongistället för standardbetong för utbyggnaden av Sickla reningsverk beräknades till 40%.

Thesis (M.A.)--University of Wisconsin--Madison, 2006.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (p. 120-123).

The continuous microreactor-assisted solution deposition (MASD) process was used for the deposition of CdS thin films on fluorine-doped tin oxide (FTO) glass. The MASD system, including a T-junction micromixer and a microchannel heat exchanger is capable of isolating the homogeneous particle precipitation from the heterogeneous surface reaction. The results show a dense nanocrystallite CdS thin films with a preferred orientation at (111) plane. Focused-ion-beam was used for TEM specimen preparation to characterize the interfacial microstructure of CdS and FTO layers. The band gap of the microreactor-assisted deposited CdS film was determined at 2.44 eV. X-ray Photon Spectroscopy show the bindings of energies of Cd 3d₃/₂, Cd 3d₅/₂, S 2p₃/₂ and S 2p₁/₂ at 411.7 eV, 404.8 eV, 162.1 eV, and 163.4 eV, respectively. The film growth kinetics was studied by measuring the film thickness deposited from 1 minute to 15 minutes in physical (FIB-TEM) and optical (reflectance spectroscopy) approaches. A growth model that accounts for the residence time in the microchannel using empirical factor (η) obtained from previous reported experimental data. Applying this factor in the proposed modified growth model gives a surface reaction rate of 1.61*10⁶ cm⁴ mole⁻¹s⁻¹, which is considerable higher than the surface reaction rates obtained from the batch CBD process. With the feature of separating homogeneous and heterogeneous surface reaction, the MASD process provides the capability to tailor the surface film growth rate and avoid the saturation growth regime in the batch process. An in situ spectroscopy technique was used to measure the UV-Vis absorption spectra of CdS nanoparticles formed within the continuous flow microreactor. The spectra were analyzed by fitting the sum of three Gaussian functions and one exponential function in order to calculate the nanoparticle size. This deconvolution analysis shows the formation of CdS nanoparticles range from 1.13 nm to 1.26 nm using a residence time from 0.26 s to 3.96 s. Barrier controlled coalescence mechanism seems to be a reasonable model to explain the experimental UV-Vis data obtained from the continuous flow microreactor, with a rate constant k' value of 2.872 s⁻¹. Using CFD, low skewness value of the RTD curve at high flow rate (short τ) suggests good radial mixing at high flow rate is responsible for the formation of smaller CdS nanoparticles with a narrower size distribution. The combination of CdS nanoparticle solution with MASD process resulted in the hindrance of CdS thin film deposition. It is hypothesized that the pre-existing sulfide (S²⁻) ions and CdS nanoparticles changes the chemical species equilibrium of thiourea hydrolysis reaction. Consequently, the lack of thiourea slows down the heterogeneous surface reaction. To test the scalability of the MASD process, a flow cell and reel-to-reel (R2R)-MASD system were setup and demonstrated for the deposition of CdS films on the FTO glass (6" x 6") substrate. The film deposition kinetics was found to be sensitive to the flow conditions within the heat exchanger and the substrate flow cell. The growth kinetics of the CdS films deposited by R2R-MASD process was investigated by with a deposition time of 2.5 min, 6.3 min, and 9 min. In comparison with the continuous MASD process, the growth rate in R2R-MASD is higher, however more difficult to obtain a linear relationship with the deposition time.
Graduation date: 2012
Access restricted to the OSU Community at author's request from Jan. 13, 2012 - Jan. 13, 2013