Effect of some mouthwashes on the corrosion and tribocorrosion behavior of a Co-Cr dental casting alloy

Dissertação de Mestrado (Ciclo de Estudos Integrados Conducentes ao Grau de Mestre em Engenharia de Materiais)Co-Cr alloys are widely used fabrication of removable partial dentures (RPDs), particularly as a dental framework. These alloys replaced noble metal alloys, due to better mechanical properties, corrosion resistance and lower cost. The oral cavity is a complex environment that frequently changes in response to the intake of food, beverages, and drugs. The use of mouthwashes is known as an effective method of preventing dental caries. Several studies have been carried out on the electrochemical corrosion and metallic ion releasing on titanium, titanium alloys, and Co-Cr alloys. However, studies related to the effect of mouthwash on electrochemical behavior of Co-Cr alloys are still limited. Even a wash with a mouthwash tooks approximately 30 seconds, the mouthwash is kept in the mouth during more time. Thus, the micromovements between the framework and the teeth or even some particles of food in contact with the framework can lead to wear. So, it is important to study the tribocorrosion behavior due to the combined action between the wear and corrosion with the presence of mouthwashes. Four different commercial mouthwashes were chosen and artificial saliva was used as control group in order to investigate the corrosion and tribocorrosion behavior of Co-Cr dental alloy. Results showed that there was no significant influence of the mouthwashes on the corrosion behavior of the Co-Cr dental alloy. However the tribocorrosion behavior of Co-Cr alloy in mouthwash containing solutions presented both higher open circuit potential values and lower coefficient of friction. Thus, it can be stated that the presence of mouthwashes did not affect negatively the tribocorrosion behavior of Co-Cr dental alloy.As ligas de Co-Cr são bastante usadas para produzir próteses parciais removíveis (PPRs) e especificamente no caso do framework dentário. Estas ligas vieram substituir ligas metálicas nobres, devido a apresentarem melhores propriedades mecânicas, resistência à corrosão e baixo custo. A cavidade oral é um ambiente complexo que frequentemente se altera devido à interação com alimentos, bebidas e medicamentos. O uso de elixires dentários é conhecido como sendo um método efetivo para a prevenção de cáries. Existem vários estudos relativos ao comportamento eletroquímico e à libertação de iões metálicos de titânio, ligas de titânio e ligas de Co-Cr. Contudo, estudos relativos ao efeito da presença de elixires dentários no comportamento à corrosão de ligas dentárias é ainda escasso. Mesmo que uma lavagem com um elixir dentário dure aproximadamente cerca de 30 segundos, o elixir dentário permanece na boca durante mais tempo. Assim, os micro-movimentos entre o framework e os dentes ou mesmo algumas partículas de comida em contacto com o framework poderão levar ao desgaste. Deste modo, é importante estudar o comportamento de tribocorrosão devido a uma ação combinada entre desgaste e corrosão com a presença de elixires dentários. Quatro elixires dentários disponíveis no mercado foram escolhidos e saliva artificial foi usada como grupo de controlo, de modo a estudar o efeito desses elixires no comportamento à corrosão e à tribocorrosão de uma liga de Co-Cr. Os resultados mostraram que não existe uma influência significativa da presença de elixires dentários no comportamento à corrosão da liga de Co-Cr. Contudo, sob ação mecânica o comportamento à tribocorrosão da liga de Co-Cr na presença dos elixires dentários apresentou valores de potencial de circuito aberto mais altos e valores de coeficiente de atrito mais baixos. Assim sendo, pode ser dito que a presença de elixires dentários não afeta negativamente o comportamento à tribocorrosão da liga de Co-Cr

Fragmentation and clustering in vertically linked industries

This paper models the location of two vertically related firms in a low labor cost country and in a country with a large market. The upstream industry is more labor intensive than the downstream industry. We find that spatial fragmentation occurs for low values of the input-output coefficient and intermediate values of the transport rate, particularly if the countries are very asymmetric in size. Otherwise, we obtain agglomeration either in the low cost country (when the transport rate is low) or in the large market (when the transport rate is high). Multiple agglomerated equilibria arise when the transport cost of the intermediate good is significant.info:eu-repo/semantics/publishedVersio

Modes of infrastructure financing and the ‘Big Push’ in development economics

In an economy where different agents undertake simultaneous and interdependent investments, this paper models the possibility that the outcome where some players invest and others do not invest is sustained in Nash equilibrium. It is well known that in models where all goods are financed through prices charged by the suppliers (“tolls” in the case of transport infrastructures), there are only two coordination equilibria: the “Big push” equilibrium, where every agent involved invests; and the “Poverty trap”, whenever none invests. We consider a two person simultaneous game, where the Government decides whether to build a highway and a firm producing a composite good decides whether to use it. Instead of resorting to tolls, the infrastructure is funded through an income tax that falls on wages. Having the Government supplying the highway and the firm not using it is a Nash equilibrium if the employment generated by the construction of the highway is intermediate and the rate of the wage income tax is high. The proliferation of unused transport infrastructures in Southern Europe seems to be related with low effects of public works upon the demand for labor and with demand- depressing “austerity” macroeconomic policies

Coordination and development

This paper addresses the issue of industrial development using a coordination game. Complementarities between transport infrastructure provision by the Government and consumer goods manufacturing firms, and among consumer goods firms themselves dictate the outcome: either the transport infrastructure (i.e., a highway) is not built and firms keep doing “home” production, thus supplying mainly nearby consumers and dispensing with a highway; or they switch to “factory” production, a more spatially centralized regime, where output must be sold over long distances, thus implying the construction of a highway. In relation to the existent literature, this paper presents two main innovations. Firstly, the two sources of linkage, namely cost linkage, through the provision of an indivisible input (the highway), and demand linkage, through the wage rise brought about by industrialization, are not treated separately, but they are integrated in the same model. Consequently, the game has now two levels of equilibrium selection. Secondly, the paper does not limit itself to checking that there can arise multiple Nash equilibria under certain circumstances, but it discusses methods for the selection of a unique outcome. Consequently, in addition to the classical Nash equilibria mentioned above, there is a third possible solution where the Government builds the highway but the consumer goods firms refrain from using it and stick to “home” production. Hence, the transport infrastructure becomes a “white elephant”

Coordination and development

This paper addresses the issue of industrial development using a coordination game. Complementarities between transport infrastructure provision by the Government and consumer goods manufacturing firms, and among consumer goods firms themselves dictate the outcome: either the transport infrastructure (i.e., a highway) is not built and firms keep doing “home” production, thus supplying mainly nearby consumers and dispensing with a highway; or they switch to “factory” production, a more spatially centralized regime, where output must be sold over long distances, thus implying the construction of a highway. In relation to the existent literature, this paper presents two main innovations. Firstly, the two sources of linkage, namely cost linkage, through the provision of an indivisible input (the highway), and demand linkage, through the wage rise brought about by industrialization, are not treated separately, but they are integrated in the same model. Consequently, the game has now two levels of equilibrium selection. Secondly, the paper does not limit itself to checking that there can arise multiple Nash equilibria under certain circumstances, but itdiscusses methods for the selection of a unique outcome. Consequently, in addition to the classical Nash equilibria mentioned above, there is a third possible solution where the Government builds the highway but the consumer goods firms refrain from using it and stick to “home” production. Hence, the transport infrastructure becomes a “white elephant”info:eu-repo/semantics/publishedVersio

The role of infrastructure efficiency in economic development : the case of underused highways in Europe

In this paper, we establish a two way causality between the phenomenon of the infrastructure which is underused (the so called “white elephant case”) and the aggregate productivity level (TFP) of the economy. On the one hand, the fact that a transport infrastructure is not used so much as it could be is itself a cause of low TFP, because it represents a low productivity for an important item of social capital. On the other hand, low aggregate productivity makes firms strategies founded on large scale of production and exports more risky, given the possibility that the political decision to build the required transport infrastructure may never be taken.info:eu-repo/semantics/publishedVersio

Formação de um grupo teatral na escola: Dificuldades e possíveis soluções para a introdução da linguagem teatral em alunos de uma instituição em um horário extraclasse

Este artigo pretende discutir a realidade de uma escola localizada numa região central de Florianópolis no estado deSanta Catarina, onde os alunos por uma questão geográfica teoricamente teriam acesso às atividades culturais e teatrais,no entanto, na prática o professor de artes que inicia um trabalho teatral com uma turma, tem sempre que partir doinício. Não existe uma continuidade no que é trabalhado com determinada turma em sala. Isto acaba por se agravar a partir do momento em que a disciplina Teatro, não está categorizada neste momento como uma disciplina obrigatória dentro da grade escolar

O problema em torno do conceito de “raça”: será que a “raça” é uma ilusão?

info:eu-repo/semantics/publishedVersio

Autosomal recessive cholesterol deficiency in a holstein calf

Cholesterol deficiency (CD), a newly identified autosomal recessive inherited genetic defect in Holstein cattle, has been reported to have unresponsive diarrhea as a clinical sign, failure to thrive, hypocholesterolemia and the animals usually die within the first weeks or months of life. CD is caused by a mutation of the bovine apolipoprotein B gene (APOB). The objective of the present report is to describe the clinical and pathological phenotype, understand the steps needed to perform a correct diagnosis and execute a treatment of the affected Holstein calf homozygous for the APOB mutation. One Holstein calf with clinical history of intermittent diarrhea and erosions in the buccal cavity was admitted to the Clinic for Ruminants of Facoltà di Medicina Veterinaria dell’Università degli Studi di Bologna, Italy. Furthermore, there was blood collected from 3 related healthy cows (mother, sister 1, sister 2) and semen from the father. This case report included a full clinical description of the clinical phenotype and pathological phenotype, blood hematological and biochemical analysis, and measurements of cholesterol and triglycerides (TG). The animal suffered a natural death 33 days after the admission to the clinic. A genetic test was performed as described by Menzi et al. (2016) using blood for sampling (affected calf, mother, sister 1, sister 2) and semen (father) to determine the APOB genotype. The calf was confirmed homozygous for the APOB mutation. The father and the mother, as expected, were heterozygous carriers of the APOB mutation and the sisters were free of the APOB mutation. The clinical phenotype of the affected calf included muscular atrophy, retarded growth, and chronic diarrhea. Hypocholesterolemia and low TG concentrations was present in the affected the calf. Additionally, the cholesterol concentration of the mother of the affected calf was also lower. The pathological phenotype of homozygous calf was steatorrhea with a segmental enteritis. Although the animal, whilst alive, did not present neurological signs, the brain presented hyperemia of meningeal vessels and a slight cerebral edema. CD must be considered as a possible differential diagnosis for chronic diarrhea and failure to thrive in Holstein calves with no evidences of primary infections. Confirmation of the associated APOB mutation is needed