949 resultados para conformational map
Resumo:
Leadership and Management in Engineering, January 2009
Resumo:
Trabalho de Projeto apresentado como requisito parcial para obtenção do grau de Mestre em Ciência e Sistemas de Informação Geográfica
Resumo:
Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies
Resumo:
Probing micro-/nano-sized surface conformations, which are ubiquitous in biological systems, by using liquid crystal droplets, which change their ordering and optical appearance in response to the presence of more than ten times smaller cellulose based micro/nano fibers, might find new uses in a range of biological environments and sensors. Previous studies indicate that electrospun micro/nano cellulosic fibers produced from liquid crystalline solutions could present a twisted form [1]. In this work, we study the structures of nematic liquid crystal droplets threaded by cellulose fibers prepared from liquid crystalline and isotropic solutions as well as droplets pierced by spider-made fibers [2]. Planar anchoring at the fibers and planar and homeotropic at the drop surfaces allowed probing cellulose fibers different helical structures as well as aligned filaments.
Resumo:
The bacterium Geobacter sulfurreducens (Gs) is capable of oxidizing a large variety of compounds relaying electrons out of the cytoplasm and across the membrane in a process designated as extracellular electron transfer. The Gs genome was fully sequenced and a family composed by five periplasmic triheme cytochromes c7 (designated PpcA-E) was identified. These cytochromes play an important role in the reduction of extracellular acceptors. They contain approximately 70 amino acids, three heme groups with bis-histidinyl axial coordination, and share between 57 and 77% sequence identity. The triheme cytochrome PpcA is highly abundant in Gs and is most likely the reservoir of electrons destined for outer surface. In addition to its role in electron transfer pathways this protein can perform e-/H+ energy transduction, a process that is disrupted when the strictly conserved aromatic residue phenylalanine 15 is replaced by a leucine (PpcAF15L). This Thesis focuses on the expression, purification and characterization of these proteins using Nuclear Magnetic Resonance and ultraviolet-visible spectroscopy. The orientations of the heme axial histidine ring planes and the orientation of the heme magnetic axis were determined for each Gs triheme cytochrome. The comparison of the orientations obtained in solution with the crystal structures available showed significant differences. The results obtained provide the paramagnetic constraints to include in the future refinement of the solution structure in the oxidized state. In this work was also determined the solution structure and the pH-dependent conformational changes of the PpcAF15L allowing infer the structural origin for e-/H+ energy transduction mechanism as shown by PpcA. Finally, the backbone and side chain NH signals of PpcA were used to map interactions between this protein and the putative redox partner 9,10-anthraquinone-2,6-disulfonate (AQDS). In this work a molecular interaction was identified for the first time between PpcA and AQDS, constituting the first step toward the rationalization of the Gs respiratory chain.
Resumo:
A perceção tridimensional é uma área em crescente desenvolvimento. Não existindo uma tecnologia ideal capaz de percecionar todo o tipo de cenários, têm surgido estudos sobre a aplicabilidade de diferentes tecnologias de forma a obter modelos que melhor se aproximem da realidade. Propõe-se nesta dissertação o desenvolvimento de um sistema de baixo-custo de percepção tridimensional que seja portátil e acessível na sua aplicabilidade, de forma a ter a capacidade de percecionar tridimensionalmente espaços interiores com pouca iluminação, tais como as divisões de um edifício ou os canais de uma mina subterrânea. Utilizou-se a triangulação entre uma câmara digital, os pontos de uma linha laser e um emissor laser para a obtenção dos dados tridimensionais do cenário. Para isso, recorreu-se a metodologias de processamento digital de imagens para a construção dos modelos dos cenários. Para se obter a validação desta dissertação, realizaram-se testes do protótipo de forma a determinar as suas capacidades percecionais. Em primeiro lugar realizou-se uma bateria de testes de calibração onde, repetidamente, se estudaram isoladamente pontos do cenário para verificar a precisão do sensor. Após esta calibração, estudou-se a capacidade de transformação de uma linha laser projetada num conjunto de coordenadas. Finalmente testou-se a capacidade de perceção tridimensional por rotação do sensor, de forma a realizar a transformação de múltiplas projeções de linhas laser num conjunto de coordenadas em torno do sensor. Verificou-se: no teste de calibração, a obtenção de distâncias com erro médio relativo inferior a 1%; no teste da linha laser, a capacidade de perceção de profundidade de múltiplos pontos ao longo da mesma; no teste de rotação, a aquisição de múltiplos conjuntos de linhas de profundidade no cenário, por rotação do sensor. Os resultados dos testes de validação permitiram concluir a viabilidade de utilizar a triangulação na aquisição de conjuntos de coordenadas de espaços interiores.
Resumo:
The organizer is a ciliated signalling transient organ, responsible for the patterning of embryo tissues during embryonic development. In higher vertebrates, such as mouse and chick, this organizer (the node and the Hensen’s node, respectively) performs dorsalventral and anteriorposterior axis definition, as well as left-right patterning of the internal organs. In lower vertebrates, such as frog and zebrafish, there is a separate specialized organ for left-right purposes called the Gastrocoel Roof Plate (GRP) and Kupffer’s Vesicle (KV), respectively. It is known that mouse and chick organizer cells give rise to structures like floor plate, notochord, hypochord and somites. Frog GRP originates all these but floor plate. In zebrafish, at 13-14 somite stage (ss) the KV finished its left-right patterning but what happens to this organizer’ cells is still poorly studied. This research attempts to understand the fate and behaviour of the KV cells. We followed the fate of KV cells by live imaging and by tight time-courses with fixed larvae. We assessed in detail their proliferative and death profile, as well as cilia length progression from 9-10 ss until 29-30 ss. We conclude that the KV cells mostly follow the evolutionarily conserved fates described for other organizers. These cells mainly incorporate the notochord and hypochord; few cells incorporate the floor plate and the somites. As a novelty, it is also hypothesized that the hypural cell fate may be among the KV cell fates.
Resumo:
The present Working Project aims at studying the topic of assurance mapping in a specific organizational context of a Portuguese retail company. For this purpose, an assurance map framework was designed to support the decision making process of stakeholders, through the delivery of comfort concerning risks, operations and control. In the end, the framework was successfully implemented for the process sourcing of goods in two business units of the company. Although, further implementation of the framework proved not to be feasible during the project’s timespan, it is expected to occur in the near future.
Resumo:
One of the first scientific maps of the Amazon region, The Course of the Amazon River (Le Cours de La Rivière des Amazones), was constructed by Nicolas Sanson, a French cartographer of the seventeenth century, and served as the prototype for many others. The evaluation of this chart, until now, has been that it is a very defective map, a sketch based on a historical account, according to the opinion of La Condamine. Thus, the aim of the present work was to prove that the map of the Amazon River traced by Nicolas Sanson is a scientific work, a map that presents precise geographic coordinates considering its time, shows a well-determined prime meridian, and also employs a creative methodology to deduce longitudes from latitudes and distances that had been covered. To show such characteristics, an analysis of the accuracy of the map was made by comparing its latitudes and longitudes with those of a current map. We determined the prime meridian of this map and analyzed the methodology used for the calculation of longitudes. The conclusion is that it is actually a good map for the time, particularly considering the technology and the limited information that Sanson had at his disposal. This proves that the negative assertion of La Condamine is unfounded.
Resumo:
v.21:no.2(1934)
Resumo:
v.21:no.3(1935)