Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Inventado no início dos anos 1980, o STM evoluiu para uma importante ferramenta na investigação das propriedades de superfícies e interfaces, com aplicações em várias áreas da ciência além da Física, como Ciências de Materiais e Química. O presente trabalho trata da microscopia de tunelamento, que se baseia no fenômeno do tunelamento quântico dos elétrons. No STM, a distância entre ponta e a amostra é reduzida até que as funções de onda dos elétrons na ponta e na superfície da amostra se sobreponham. Nessa situação, observa-se o fenômeno do tunelamento quântico de elétrons através da barreira formada entre os dois eletrodos (ponta e amostra). Como o valor da corrente de tunelamento é fortemente dependente da distância ponta-amostra, um microscópio STM pode ser utilizado para mapear a morfologia da superfície da amostra com alta resolução espacial. Além disso, outra importante capacidade do STM é a possibilidade de atuar no modo espectroscópico (STS). Por vezes, o estudo detalhado das propriedades de um sistema requer o uso de métodos não convencionais de microscopia STM. Um exemplo é o estudo do magnetismo de nanoestruturas por microscopia de tunelamento com resolução em spin (SP-STM). A implementação destes métodos não convencionais normalmente exigem recursos experimentais específicos, nem sempre disponíveis em equipamentos comercias. A versatilidade no controle das características funcionais do equipamento foi a principal razão que nos motivou a construir o microscópio STM. No primeiro capitulo faremos uma introdução geral ao tema da dissertação. Uma breve introdução ao método de STM será dada no capítulo 2, incluindo aspectos fundamentais do tunelamento quântico, bem como sua aplicação técngeralica. O capítulo 3 descreve o estudo das propriedades eletrônicas e magnéticas do grafeno preparado sobre a superfície vicinal Ni(977). O magnetismo observado na camada de grafeno induzido por um substrato ferromagnético é de grande interessante para o desenvolvimento de dispositivos spintrônicos. Relatamos a investigação das propriedades de uma monocamada de grafeno preparada sobre de Ni(977) por CVD, utilizando a microscopia de varredura por tunelamento (STM), dicroísmo circular magnético de raios-x (XMCD) e espectroscopia de fotoelétrons (XPS). No capítulo 4, apresentamos o detalhamento do projeto de construção de um STM para operar em ambiente de ultra alto vácuo (UHV). Características do STM como isolamento de vibração, desenho mecânico, sistema de varredura e processo de preparação de pontas são discutidos. Por fim, analisamos os resultados dos testes de operação no microscópio STM, dificuldades observadas ao longo do projeto e possíveis melhorias. / Invented in the early 1980s, STM has evolved into a standard tool to investigate the properties of surfaces and interfaces, with applications in various research fields, such as physics, material sciences and chemistry. The present work deals with scanning tunnelling microscopy, which refers to the quantum phenomenon of electron tunneling through a potential barrier. The distance between a conductive probe tip and sample is reduced until the electron wave functions of tip and sample surface have significant overlap, and electrons can tunnel through the vacuum barrier. As the so-detected tunneling current is strongly distance-dependant, it can be used to map the morphology of the sample surface with a resolution which goes far beyond the actual meaning of the term microscopy. Besides its unique spatial resolution, one strength of the STM is the possibility to perform local electronic spectroscopy. STM has evolved into a standard tool to investigate the properties of surfaces and interfaces, with applications in various research fields besides physics, such as material sciences, chemistry, or biology. Nevertheless, the detailed study of materials properties requires the use of non-conventional methods of STM microscopy. One example is the study of magnetism in nanostructures by spin polarized scanning tunneling microscope (Sp-STM). The implementation of such unconventional methods typically requires specific experimental features, not always available in commercial equipment. This versatility in controlling the functional characteristics of the equipment was one of the main reasons that motivated us to design and build our own STM microscope. A general introduction to the dissertation theme is presented in chapter 1. In chapter 2, a brief discussion about the method of STM is developed, including theoretical aspects on quantum tunneling. In chapter 3, the experimental study of electronic and magnetic properties of the graphene/Ni(977) is shown. The recent observation of magnetism in graphene layers induced by a ferromagnetic substrate is a very interesting issue and can impact the design of new carbon-based spintronic devices. Here we report on the investigation of the electronic and magnetic properties of the graphene/Ni(977) by using scanning tunneling microscope (STM), x-ray magnetic circular dichroism (XMCD) and x-ray photoelectron spectroscopy (XPS). In chapter 4, it was described the project and construction of a homemade STM operated in ultrahigh vacuum (UHV) condition. We discuss the details of main STM-UHV components: main and sample preparation chambers, STM head, tip scanner, and sample holder design. Characteristics of the mechanical and electronic design, vibration isolating system, tip and sample preparation are discussed. Finally, we report the results of testing experiments as well as discuss the encountered difficulties and some possible solutions.

Eukaryotic translation initiation factor 5A (eIF-5A) is the only known cellular protein that contains the post-translationally derived amino acid, hypusine. Initially, eIF-5A was named as a translation initiation factor because of its capability to stimulate the formation of methionyl-puromycin, which mimics the first peptide bond formation during protein synthesis, under <em>in vitro</em> conditions. Subsequently, however, this proposed function of eIF-5A has been questioned because a similar effect on translation was not observed <em>in situ</em>. Moreover, eIF-5A appears not to be required for general protein synthesis. Rather, there is evidence that it facilitates the translation of specific subsets of mRNAs required for cell proliferation as well as apoptosis. <br /><br /> There are two isoforms of eIF-5A in the human genome which have designated eIF-5A1 and eIF-5A2. The objective of the present study was to gain an increased understanding of the roles of eIF-5A1 and eIF-5A2 during apoptosis and cell proliferation using human cell lines as a model system. Apoptosis was induced by treating the cells with Actinomycin D or sodium nitroprusside (SNP), which initiate programmed cell death by different mechanisms. It was observed for both normal and cancer cells that eIF-5A1 protein is up-regulated during apoptosis induced by Actinomycin D or SNP, whereas eIF-5A1 mRNA is constitutively expressed and does not change in abundance during this treatment. The up regulation of eIF-5A1 protein levels in the absence of a corresponding up-regulation in eIF-5A1 mRNA suggests that eIF-5A1 may be post-transcriptionally regulated. Moreover, eIF-5A1 protein up-regulation was stronger in normal cells than in cancer cells. By contrast, eIF-5A2 protein was below detection levels during apoptosis in both normal and cancer cells, although the corresponding transcript was detectable by semi-quantitative RT-PCR. This is attributable to inefficient translation of eIF-5A2 mRNA. <br /><br /> The effects of eIF-5A1 and eIF-5A2 on cell proliferation were examined by modulating the levels of serum in cultures of UACC-1598 cells, which are ovarian cancer cells that express high levels of both isoforms of eIF-5A. Serum starvation, which induces cell cycle arrest and ensuing apoptosis, followed by the re-addition of serum had no effect on the transcript levels of either eIF-5A1 or eIF-5A2. However, eIF-5A1 and eIF-5A2 proteins were both up-regulated within 24 hours of the initiation of serum starvation, and this coincided temporally with the onset of apoptosis as measured by TUNEL and a subsequent decline in viable cells. <br /><br /> The data indicate that eIF-5A1 and eIF-5A2 are both post-transcriptionally regulated and that they have functionally redundant roles in apoptosis.

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[pt] O uso de métodos geofísicos nas engenharias civil, de minas e ambiental cresceu significativamente nas últimas décadas, e continua se expandindo na medida em que há uma queda em seus custos, decorrente do maior domínio da metodologia por parte de especialistas, bem como um maior conhecimento das técnicas existentes por parte dos engenheiros, que geralmente são os responsáveis por especificar as técnicas de investigação em um empreendimento. Este trabalho apresenta alguns dos métodos de investigação rasa mais utilizados, analisando-os do ponto de vista de sua aplicação em obras lineares. São analisados ainda alguns casos de estudos realizados, apresentando-se por fim uma sugestão de fluxograma de trabalho a partir das lições aprendidas nestes casos. / [en] The use of geophysical methods in Civil, Environmental and Mining Engineering has significantly grown over the past years, and continues to grow due to lower costs, which is a consequence of the greater knowledge by specialists, as well as more access to information on its benefits by engineers, usually the ones to define the survey methods. This piece presents some of the most used methods of shallow investigation, analyzing them based on their applicability on linear structures. Some real cases are presented and studied, and a suggestion of workflow is made based on the lessons learnt on those cases.

Ingeniero Civil Mecánico / La creciente utilización de sistemas de generación de energía renovable ha provocado un aumento importante en la investigación y desarrollo de estas tecnologías. Particularmente, el campo de la generación mediante energía eólica es uno de los más importantes hoy en día. Un factor determinante en la capacidad de generación a través de energía eólica es la eficiencia de las turbinas. Es común en estas máquinas encontrar eficiencias en torno al 45\%, Entre los factores que determinan la eficiencia están los aspectos geométricos y aerodinámicos de la turbina, y la estela turbulenta generada por las palas y el rotor. Esta ultima en particular es determinante tanto en la eficiencia individual de aerogeneradores como en la eficiencia global en el caso de parcelas eólicas, debido a la interferencia entre distintas turbinas. Se sabe que la gran mayoría de las pérdidas de eficiencia de las turbinas eólicas se deben a turbulencias generadas por las palas del rotor, por lo que la minimización de estas es el objetivo principal de los diseñadores hoy en día. Estos aspectos motivaron este trabajo de título, en el cual estudiamos experimentalmente el funcionamiento de una turbina eólica al interior de un túnel de viento mediante anemometría de hilo caliente. Se diseñó y construyó un modelo a escala de un aerogenerador y se instaló dentro del túnel de viento del laboratorio LEAF-NL, de la Universidad de Chile Se midió la potencia de la turbina como función de la velocidad de flujo del túnel de viento en un rango de velocidades de flujo de entre 0.5 y 3 [m/s] (TSR o tip speed ratio de 1.1 a 5.3), lo que entrega como resultado la curva característica de los aerogeneradores (curva S). A través un sistema de posicionamiento motorizado en 2D se midió el campo de velocidades en distintos planos transversales de la estela. Para esto se utilizó un anemómetro de hilo caliente operado de manera síncrona con la posición angular instantánea del rotor de la turbina, con el objetivo de realizar una detección coherente de la velocidad en la estela con la posición angular del rotor. De esta manera se obtuvo el campo de velocidades medio y fluctuante asociado a la posición de las palas de aerogenerador. La medición sincronizada de los promedios temporales de velocidad permite identificar la influencia de cada de cada pala en la estela y además identificar la distribución de intensidad turbulenta. Finalmente se generaron mapas de velocidad en distintos planos de corte transversal a la estela, con lo que adicionalmente se logró evaluar la expansión de la estela y poder obtener un parámetro de razón de áreas, dicho parámetro permite calcular con éxito los coeficientes de potencia y empuje (Cp y Ct), los cuales coinciden con los valores reales medidos.

This thesis focuses on problem with detection of cavitation in hydraulic systems and devices. Thesis works with data from cavitation tunnel experiment, where cavitation appeared on blade. It founds out if time records and their frequency spectrum is dependent on operating conditions. Data are examined by various statistic methods. All of that is then used in method called neural network.

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One of the major problems of modern Internet is the upcoming depletion of addressing space in IPv4 protocol. This master thesis focuses on the study of network protocol IPv6, the possibilities of expanding this protocol in the Internet using the appropriate tunelling method and ways of tunnel management, especially the TIC protocol. Major goal of this work is using knowledge of protocols in a design and implementation of the server part of tunnel broker system, which uses mentioned tunneling method and is compatible with the open source client AICCU. Second part of this work deals with testing and pilot deployment of this system. Main benefit consists in creation an open source tunel broker system. Real deployment of this system is particularly advantage for Czech users as a low latency tunnel IPv6 Internet.

Ansamling av amyloid beta (Aβ) i de extracellulära miljöerna är associerad till många svåra sjukdomar som Alzheimers och ålders-relaterad makuladegeneration (AMD). Amyloider karaktäriseras av att de är olösliga, toxiska mot neuron och orsakar därför svår skada. AMD är den ledande orsaken till blindhet och irreversibelt förlorande av skarp syn då Aβ manifesterar i makula. I AMD orsakar Aβ inflammatorisk aktivitet där det retinala pigmentepitelet bryts ned och ljuskänsliga fotoreceptorer dör genom apoptos. Idag lever ca 150 miljoner människor med AMD där mänga har svårt att utföra vardagliga uppgifter till följd av förlust av skarp syn. Idag är Kongo röd en av de vanligaste metoderna för att visualisera amyloider in vitro. Den patogenes som orsakas av amyloider kan analyseras med immunofluorescens och immunohistokemi. Syftet med studien var att undersöka förekomst av amyloider i samband med celldöd i näthinna från gris, undersöka den patogenes som amyloider orsakar med immunofluorescens och immunohistokemi, samt undersöka om det finns korrelation mellan amyloider och celldöd. Resultatet visade att amyloider var förekommande i näthinnan och hade orsakat celldöd och ansamling av aggresomer. Amyloider och den patologi som orsakats kunde visualiseras i det yttre lagret av näthinnan. / Deposition of amyloid beta (Aβ) in the extracellular environment are associated to some severe diseases, like Alzheimer’s disease and age-related macular degeneration (AMD). Amyloids are characterized by insolubility, toxicity towards neuron and are there-for damaging to tissues. AMD is the primary cause of blindness and irreversible loss of central vision through manifestation of Aβ in the macula. In AMD, Aβ drives an inflammatory action that degenerates the retinal pigment epithelium and cause atrophy of photoreceptors. Today ~150 million people live with AMD where many find difficulties performing everyday tasks due to loss of sharp vision. Congo red is a gold standard for visualizing amyloids in vitro and the pathogenesis caused by amyloids can be analyzed by immunofluorescence and immunohistochemistry. The purpose of this study was to show the presence of amyloids relating to cell death in pig retina, show the pathogenesis caused by amyloids by using immunofluorescence and immunohistochemistry, and investigate whether there is correlation between amyloids and cell death. The result showed that amyloids were present in the retina and caused cell death and gathering of aggresomes. Amyloids and the caused pathology could be visualized in the outer layer of the retina.