Orientador: Aparecida Conceição Boliani / Banca: Luiz de Souza Corrêa / Banca: Enes Furlani Junior / Banca: Fernando Alves de Azevedo / Banca: José Carlos Cavichioli / Resumo: A evolução da bananicultura brasileira foi possível em virtude dos progressos obtidos no que se refere à disponibilidade de material genético diversificado, à disponibilidade de mudas sadias e de boa qualidade genética, às práticas culturais de manejo pré e pós-colheita, às técnicas fitossanitárias desenvolvidas, às técnicas de nutrição e de irrigação, e à melhoria do nível técnico e organizacional do bananicultor brasileiro. Métodos de propagação, como a micropropagação in vitro, vêm sendo desenvolvidos e aperfeiçoados, para elevar a taxa de multiplicação em curto espaço de tempo e melhorar a qualidade das mudas. O processo de micropropagação é realizado em fases, sendo estas a escolha da planta matriz, desinfestação do material, estabelecimento, multiplicação enraizamento e aclimatação das mudas. Objetivou-se com este trabalho estabelecer um protocolo de micropropagação de explantes de bananeira 'Thap maeo', envolvendo as etapas de desinfestação utilizando concentrações de cloro ativo e os antibióticos ampicilina sódica e cloranfenicol, multiplicação estudando concentraçoes de citocininas como o 6-Benzilaminopurina (BAP) e Cinetina e no enraizamento in vitro verificando concentrações de auxinas como o Ácido Indol Butírico (AIB) e o Ácido Naftaleno Acético (ANA). Concluiu-se que a concentração de 2% de cloro ativo proporcionou redução de 92% e 88% respectivamente para bactérias e fungos. Para os antibióticos ampicilina sódica e cloranfenicol a concentração de 20 mg L-1 reduziu em 70% de desinfestação de bactérias e fungos. Quando se utilizou os reguladores vegetais, BAP e cinetina, o maior numero de brotos obtido foi na concentração foi de 4mg L-1 conseguindo em média 3,8 brotos por explantes no 4o subcultivo. Para o enraizamento in vitro a concentração de 4,0 mg L-1 de AIB apresentou melhor resultado com 3,2 raizes por broto / Abstract: The evolution of Brazilian banana was possible because of progress in relation to the availability of diverse genetic material, the availability of healthy seedlings and good quality genetics, cultural practices of management and post-harvest phytosanitary techniques developed techniques, nutrition and irrigation, and improving the technical and organizational bananicultor Brazil. Propagation methods, such as in vitro micropropagation, have been developed and improved to increase the multiplication rate in a short time and improve the quality of seedlings. The acclimatization process is performed in phases, these being the choice of the mother plant, disinfection equipment, establishment, multiplication, rooting and acclimatization of the seedlings. The objective of this study establish a protocol for micropropagation of banana explants 'Thap Maeo', involving the steps of disinfection using chlorine concentrations and antibiotic ampicillin sodium and chloramphenicol, multiplication studying concentrations of cytokinins like 6-Benzylaminopurine (BAP ) and Kinetin and in vitro rooting checking concentrations of auxin and Indole Butyric acid (IBA) and Naphthalene Acetic Acid (NAA). It was concluded that the 2% concentration provided a reduction of active chlorine of 92% and 88% respectively for bacteria and fungi. For the antibiotics sodium ampicillin and chloranphenicol concentration of 20 mg.L-1 reduced by 70% of disinfection of bacteria and fungi. When using the plant growth regulators, BAP and kinetin, the highest number of shoots was obtained on concentration was 4 mg L -1 achieving an average of 3,8 shoots per explant in the 4th subculture. For rooting in vitro concentration of 4.0 mg L-1 IBA showed the best result with 3,2 roots per shoot / Doutor

D.Ing. / In this dissertation a pulsed DC voltage bus comprising a full wave rectified sinusoidal voltage will be investigated for use as a link voltage. A background study into existing converter topologies for single phase uninterruptable power supplies and three phase front end converters, applicable to the study, is discussed. The definition of the bus voltage will be given as well as the power handling limitations. An experimental 3.3kW single phase UPS and a 3.3kW three phase front end converter using the bus was designed, built, tested and the results presented. The design and modelling of the two systems are discussed so as to clarify the advantages, disadvantages and limits of using such a bus. The appropriate standards pertaining the two converter systems have been looked up and the impact on the design discussed. The discussion will be concluded with a summarisation and possible future work is discussed.

Please read the abstract in the section 00front of this document / Dissertation (MEng (Electrical Engineering))--University of Pretoria, 2007. / Electrical, Electronic and Computer Engineering / MEng / unrestricted

O splicing é o processo que resulta na remoção dos íntrons e união dos éxons nos genes eucarióticos. Nesse processo diversos elementos em cis e trans estão envolvidos. Além das sequências em cis canônicas (sítios de splicing, sítio de ramificação e trato de polipirimidina), os reguladores de splicing -- sequências curtas localizadas em éxons e íntrons - são considerados de grande importância, pois auxiliam na correta determinação das fronteiras éxons/introns. Através do splicing alternativo pode-se gerar grande diversidade de transcritos e atualmente sabe-se que no mínimo, 80% dos genes humanos apresentam variantes de splicing. A evolução dos Reguladores de Splicing Exônicos (ESRs) foi principalmente analisada através de abordagens filogenéticas. Embora esses estudos tenham revelado resultados consistentes (por exemplo, evidências de seleção negativa contra mudanças sinônimas que afetam ESRs) outros ainda parecem contraditórios, como a maior conservação filogenética e a maior taxa de evolução não-sinônima dos éxons alternativos em relação aos constitutivos. Nesta tese abordamos questões sobre o regime e a intensidade de seleção que atuam sobre os éxons e seus reguladores através da comparação da variação genética intra e inter-específica. Os resultados da tese demonstram que: 1. Há uma diferença na densidade e na intensidade de seleção negativa que atua sobre os ESRs de éxons constitutivos e alternativos. 2. Os inibidores de splicing tem papel principal na origem dos éxons alternativos a partir de éxons constitutivos e também nos casos de uso alternativo de sítios de splicing. 3. O nível de inclusão dos éxons está diretamente relacionado com a intensidade de seleção negativa sobre mudanças não-sinônimas / Splicing is the process by which introns are removed from a mRNA precursor and exons are ligated to form a mature mRNA. During this process several cis and trans factors are involved. Besides the canonical cis factors (e.g., splicing sites, branch point and polypyrimidine tract), Splicing Regulators - short sequences located in exons and introns - have an important role in assisting the spliceossome to correctly recognize exon/intron boundaries. Through alternative splicing, great transcript diversity is generated, and currently it is known that more than 80% of human genes present splicing variants. The evolution of Exonic Splicing Regulators (ESRs) has been mainly analyzed by interspecific comparisons. Although these studies have revealed consistent results (evidences of weak negative selection against synonymous variations that affect ESRs), other findings still appear inconsistent, for instance the reports on increased level of conservation and higher non-synonymous evolutionary rate in alternative than constitutive exons. The present thesis investigates the regime and intensity of natural selection on exons and their ESRs by comparing intra and interspecific genetic variation. We demonstrate that 1. ESRs from constitutive and alternative exons differ significantly in density and the intensity of negative selection. 2. The exonic splicing silencers have a major role in the origin of exons skipping from constitutive exons, and also on events of alternative usage of splicing sites. 3. There is a positive correlation between the exon inclusion level and the intensity of negative selection against non-synonymous variations

A modern system-on-chip (SoC) integrates a range of analog, digital, and mixed-signal building blocks, each with a dedicated voltage domain to maximize energy efficiency. On-chip low-drop-out regulators (LDOs) are widely used to implement these voltage domains due to their advantages of high power density and the ease of integration to a complementary metal-oxide-semiconductor (CMOS) process. Recently, digital LDOs have gained large attention for their low input voltage support for emerging sub-mW SoCs, portability across designs, and process scalability. However, some of the major drawbacks of a conventional digital LDO design are (i) the trade-off between control loop latency and power dissipation which demands a large output capacitor, (ii) failure to address the performance degradations caused by the parasitics in a practical power grid, and (iii) insufficient power-supply-rejection-ratio (PSRR) and large ripple in the output voltage. Chapters 2 through 4 of this thesis present my research on the design and circuit techniques for improving the aforementioned challenges in fully-integrated digital LDOs. The first work implements a hybrid event- and time-driven control in the digital LDO architecture to improve the response and settling time-related metrics over the existing designs. The second work presents a power delivery system consisting of 9 distributed event-driven digital LDOs for supporting a spatially large digital load. The proposed distributed LDO design achieves large improvements in the steady-state and non-steady-state performances compared to a single LDO design. In the third work, we prototype a digital LDO based on new current-source power-FETs to achieve a high PSRR and low output voltage ripple. Lastly, on-chip voltage regulators have recently found usefulness in hardware security applications. An on-chip LDO can be used to improve the side-channel attack (SCA) resistance of a cryptographic core with design modifications to the classical LDO architecture. However, the existing designs incur non-negligible overheads in performance, power, and silicon area due to the conventional active-for-all-encryption-rounds architecture. In the last chapter, we propose a detection-driven activation technique to achieve a near-zero energy-delay-product (EDP) overhead in a SCA resilient digital LDO. In this architecture, the LDO can detect an attack attempt and enable SCA protection only if an attack is detected.

The opportunistic pathogen Pseudomonas aeruginosa utilizes a variety of virulence factors to infect a wide range of hosts. Virulence genes in this organism are many times controlled by two-component regulatory systems consisting of a sensor histidine kinase and a response regulator giving them high importance in research. Orphan response regulators consist of genes that have been proposed to be a response regulator but have not been studied to determine if they do work in a two-component regulatory system or not. Investigating these orphan response regulators could potentially lead to the finding of another regulator of virulence genes. Non-polar deletions were designed using splicing of genomic segments by overlapping extension. A variety of phenotypic assays, liquid-killing assays with the nematode C. elegans, and virulence assays with macrophages were utilized to determine if these orphans were different from the wild-type strain PAO1. If attenuated, these genes can be further studied to find new and novel regulators of virulence in Pseudomonas aeruginosa.

The proposed hybrid system generates AC power by combining solar and wind energy converted by a doubly-fed induction generator (DFIG). The DFIG, driven by a wind turbine, needs rotor excitation so the stator can supply a load or the grid. In a variable-speed wind energy system, the stator voltage and its frequency vary with wind speed, and in order to keep them constant, variable-voltage and variable-frequency rotor excitation is to be provided. A power conversion unit supplies the rotor, drawing power either from AC mains or from a PV panel depending on their availability. It consists of a multilevel inverter which gives lower harmonic distortion in the stator voltage. Maximum power point tracking techniques have been implemented for both wind and solar power. The complete hybrid renewable energy system is implemented in a PSIM-Simulink interface and the wind energy conversion portion is realized in hardware using dSPACE controller board.

Magister Pharmaceuticae - MPharm / Medicines have to be regulated in an effort to monitor their quality, safety, and efficacy. The process of medicines registration is lengthy, costly, and document-heavy. Many countries have limited expertise and resources at national medicines regulatory authorities (NMRAs) and some countries have adopted unified approaches to medicines registration legislation. Harmonised guidelines and initiatives have been adopted in South Africa and the Southern African Development Community (SADC). However, there are no studies that have identified the effects of these initiatives and guidelines on major stakeholders such as the pharmaceutical industry and regulators.

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