HIV establishes a reservoir comprising long lived, latently infected CD4+ T cells and monocytic cells early during primary infection. This population represents a major barrier to an HIV cure. This thesis aimed to investigate the role of the immunological synapse in the failure of cytotoxic T lymphocytes (CTLs) to eliminate the HIV reservoir and the potential for engineered bispecific <b>I</b>mmune-<b>m</b>obilising <b>m</b>onoclonal <b>T</b> cell receptors <b>A</b>gainst <b>V</b>iruses (ImmTAV) to overcome this by redirecting fully functional CD8+ T cells against viral targets. A primary cell model of latency was used to investigate the expression of HIV Gag on latently infected cells and their susceptibility to ImmTAV-mediated elimination. A subset of cells expressed low levels of Gag without spreading infection and ImmTAV-redirected healthy donor CD8+ T cells were able to eliminate up to 40% of infected cells without latency reversal. CD8+ T cells from chronic HIV infected (CHI) donors showed impaired antiviral activity even with ImmTAV redirection. To investigate this further, confocal microscopy was used to study immunological synapse formation using primary CD8+ T cells from HIV-negative and CHI donors. CD8+ T cells from CHI donors were able to form conjugates with virus-infected cells but exhibited impaired synapse maturation, indicated by reduced Zap70 localisation, delayed microtubule-organising centre polarisation and impaired perforin recruitment to the synapse. ImmTAV redirection partially overcame these defects. Finally, the impact of antiretroviral agents on T cell mitochondrial function was explored. Exposure to zidovudine increased mitochondrial reactive oxygen species production and susceptibility to apoptosis. However, there was no evidence of impaired mitophagy. These data show that defects in CD4+/CD8+ T cell synapse maturation contribute to HIV persistence but nevertheless suggest that a subset of HIV reservoir cells may be susceptible to ImmTAV-mediated elimination. The therapeutic potential of ImmTAVs may depend in part on correction of CD8+ T cell exhaustion.

Orientadores: Denis José Schiozer, Gabriel Alves da Costa Lima / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências / Made available in DSpace on 2018-08-19T18:25:23Z (GMT). No. of bitstreams: 1 Carvalho_MarcosHenriquede_M.pdf: 3436602 bytes, checksum: 6fc653eb73d82869d8e3b2d81634b94d (MD5) Previous issue date: 2011 / Resumo: A simulação de reservatório é a base para as previsões de produção, dimensionamento de equipamentos de superfície e planejamento de atividades de produção. É uma ferramenta para elaborar a estratégia de produção que gera curvas de previsão de produção de petróleo. No entanto, mesmo sem considerar incertezas geológicas e econômicas, na prática, tal curva de produção pode apresentar baixa probabilidade de ser verificada, uma vez que a disponibilidade operacional dos sistemas físicos é uma variável incerta com valor abaixo de 100%. Então, o resultado final depende de: estratégia de produção, das incertezas presentes no modelo e da confiabilidade dos sistemas (equipamentos); este último item é o foco deste trabalho. O objetivo principal deste trabalho é verificar a importância e a influência de um estudo da análise da confiabilidade dos sistemas de produção integrada com a simulação do reservatório, a fim de verificar o impacto sobre a produção de petróleo e sobre o valor presente líquido. Sendo assim, além da opção no simulador disponível para incluir, de forma simplificada, as informações de confiabilidade dos sistemas, por meio de um índice de disponibilidade média constante, foi desenvolvido um algoritmo que trata o fechamento e restabelecimento dos sistemas de forma probabilística, a fim de a operação ser tratada em um cenário mais realista. A metodologia proposta é aplicada a um campo de petróleo com óleo leve e a um campo de petróleo com óleo pesado. Com os resultados, conclui-se que, quando as informações de confiabilidade são inseridas no simulador de forma dinâmica, a produção acumulada de óleo leve não apresenta uma diferença significativa quando comparada com o caso em que as informações de confiabilidade dos sistemas não são consideradas. Por outro lado, para o campo de óleo pesado, apesar de a média também não ter apresentado diferença significativa, observa-se uma alta variação na produção de óleo. Em ambos os campos ocorre um atraso na produção, afetando o fluxo de caixa, resultando em diferenças significativas no VPL / Abstract: The reservoir simulation is the basis for the forecasts of production, dimensioning of surface equipments and the planning of activities related to production. Therefore, a production strategy which generates oil and gas production curves over the operational lifetime. However, even without considering geological and economic uncertainties, in practice, this curve presents low probability of being verified, since the operational availability of the production systems is an uncertain variable with value below 100%. Then, the final result depends on: production strategy, uncertainties present in the model and the reliability of the systems (equipments), which is the focus of this paper. The main objective of this work is to verify the importance and influence of a study of the analysis of the reliability of the production systems integrated to the reservoir simulation, in order to verify the impact on the oil production and on the net present value. Thus, besides de option in the simulator available for including, in a simplified way, the information of reliability of the systems, through an index of availability constant, it was developed an algorithm that treats the shutting and restore of the systems in a probabilistic way, in order to them be treated in a more realistic operation scenario. The proposed methodology is applied to a light oil field and a heavy oil field. With the results, it is concluded that, when the reliability information are inserted in the simulator in a dynamic way, the cumulative production of light oil does not present a significant difference when compared to the case where the reliability information of the systems are not considered. On the other hand, the heavy oil Field, despite the mean also does not present a significant difference, it is noted a high variation in the production figures. However, for both fields occurs a delay in production, affecting the cash flow resulting in significant differences in NPV / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo

M.Sc. (Aquatic Health) / Urban impoundments play both a recreational and functional role in the urban areas. From the recreational point of view these impoundments offer aesthetically pleasing environs as well as habitat for aquatic organisms in a built environment. The functional role of impoundments is related to attenuation of storm water run-off that is released into urban water courses. Storm water run-off can have adverse effects on the ecological integrity of aquatic ecosystems. Water quality will influence other physical and biological components of these systems. It is for this reason that the ecological health of impoundments is assessed from an ecotoxicological perspective, focusing on Westdene and Emmarentia dams in Johannesburg. It has become common practice to use aquatic biota to assess the impacts of human activities on aquatic ecosystems. This is because animals and plants can provide a long-term integrated reflection of water quality, quantity, habitat quality and other environmental conditions. Water and sediment quality were assessed by applying standard techniques and protocols. Fish were utilized as bioindicator organisms in order to quantify the concentrations of metals available in the dam. Abundance of the macro invertebrate community was also measured. Physico-chemical water analyses were done during each sampling period to assess the water quality against the South African Water Quality Guidelines. Ammonia, which can be toxic to aquatic life, remained high in both dams. High phosphate concentration during the low rainfall season in Westdene Dam could result in eutrophication related problems. The microbiological analysis of the water suggests that the main cause of faecal and total coliforms contamination of the impoundments possibly originates from dominant birds, African Sacred Ibis (Threskiornis v aethiopicus) and Egyptian Goose (Alopochen aegyptiaca ) in the dam and others water birds frequenting the dams. Abnormally high concentrations of the heavy metals Nickel and Chromium were found in the water body and fish (Clarias gariepinus and Tilapia sparmanii ) thus indicating bioavailabity of these metals resulting in bioaccumulation in fish. High concentration of Lead in sediment was recorded and may greatly impact benthic macroinvertebrates population and their habitat.

The aim of the study was to analyse possibilities of sustainable use of a recreational lake in the outskirts of the City Plzeň. Long term balance between economic, social and ecological aspects was emphasized. After the analyse was made it resulted that for sustainable economic functioning of the locality several measures should be carried out. The extent of the measures should be appropriate in order not to disturb sustainable maintenance of social and ecological aspects.

Sedimentation is one of the consequences of hydropower plant construction. Such structures not only have an influence on reservoir morphology, but also have great impact on both upstream and downstream river morphology. This study focuses on fluvial morphological changes in between two hydropower plants on the Drava River, Austria. The influence of both reservoir management methods (flushing) and human intervention (groynes) have been investigated. The first stage started with validating an unsteady Delft3D morphodynamic model of the meandering reach. This validation shows the importance of spatial grain size distribution in predicting bed load transport. Analysis of the flushing method includes investigation of the duration of gate-opening before and after peak flood. The results show that the duration of lowering the water level at the hydropower plant (by opening the gate) before starting the peak flood will not have a big influence on the river morphology upstream of the reservoir. However, the duration of maintaining the low water level after the peak flood has a large influence on both the river morphology in the upstream portion of the reservoir and on the sediment transport toward the reservoir In the second part of this study, hydraulic structural groynes were applied in the river reach. The objective was to design a groyne field that will minimize sediment transport to the reservoir. Both emerged and submerged groynes were investigated. In addition, the influences of both groyne head shape and the distribution of sediment grain size in the groyne zone were examined. This study shows that under an unsteady simulation, when the groynes are submerged by 1m at normal flow, the sediment supply to the groyne zone decreases compared to the emerged case. However, if the groynes are submerged by 0.5m, the sediment supply to the groyne zone will be greater than the emerged case for an aspect ratio in between (0.5-2). Finally, applying L-head groynes produces less erosion in the main stream and a higher sediment supply compared to straight groynes.

The Early Permian Unayzah A member in the Ghawar area of east-central Saudi Arabia is a prolific gas producer but is characterized by significant reservoir heterogeneity related to complex interbedding, on the scale of 5 meters or less, of eolian dune, sand sheet, interdune and ephemeral (playa) lake facies. Diagenetic products in Unayzah A developed during a continuum of eogenetic and mesogenetic reactions. Early or eogenetic cements are dominated by clay rims that formed at temperatures below 70oC. Oil migration along stylolites probably from Silurian source rocks occurred during the early mesogenetic stage followed by barite, quartz and carbonate cementation. Oil degradation at temperatures between 150o and 225oC produced acidic pore fluids that caused dissolution of earlier formed carbonates to generate secondary intragranular, moldic and micro pores. Thin, early clay and hydrocarbon rims as well as possible early microquartz cements inhibited cementation of primary intergranular pores that are only partially filled with quartz outgrowth crystals. Total porosity, including primary open pores, secondary pores, and bitumen-coated and filled pores ranges up to 27 percent. Reservoir quality and heterogeneity are a function of depositional environment and diagenesis in which eolian dune and sand sheet facies contain the highest total porosities and hence the best reservoir properties. Some previously recognized Stoke's surfaces are characterized by higher concentrations of quartz cement further compromising reservoir interconnectivity. / Master of Science

No description available.

Elevated concentrations of iron (Fe) and manganese (Mn) in drinking water degrade water quality by affecting taste, odor, and color. Under oxic conditions (dissolved oxygen (DO) >2 mg/L), Fe and Mn are rarely present in soluble form in natural waters, as they occur as insoluble, oxidized minerals in sediments. However, the development of low DO concentrations in the bottom waters of some lakes and drinking water reservoirs during thermal stratification can lead to the reduction of oxidized, insoluble Fe and Mn in sediments to soluble forms, which are then released into the water column. In response, many water utilities have installed oxygenation systems to control metal concentrations in situ in drinking water reservoirs. However, previous research has found anoxic (DO < 0.5 mg/L) conditions still develop within sediments, even with operational oxygenation systems, allowing for the reduction and release of soluble Fe and Mn into the water column. To examine the drivers of metal release from sediments into the water column, I conducted sediment flux chamber experiments to directly quantify Fe and Mn fluxes at the sediment-water interface of a small, eutrophic drinking water reservoir (Falling Creek Reservoir, Vinton, VA). The experiments were conducted twice during the 2018 summer stratification period (April 24 – October 21). Using the flux chambers, I measured total and soluble Fe and Mn concentrations under changing oxygen conditions over 10-day periods to calculate fluxes. Throughout the experiments, I monitored DO, oxidation-reduction potential (ORP), temperature, and pH. In addition to the direct measurements, I also estimated metal fluxes using a mass balance method, which relies on measurements of metal inputs and outputs into the bottom waters of the reservoir. Overall, our results showed that fluxes are highly variable during the stratification period, with some periods having positive fluxes (release of metals from sediment to the water column) and some with negative fluxes (return of metals from the water column to sediment). The metal fluxes are highly sensitive to redox conditions in the water column, sediment-water interface and sediments. Metal fluxes measured using the chambers are 91-105% higher than those estimated using the mass balance method. This difference supports result of previous work that the flux chamber method likely provides maximum values of metal fluxes as the isolated chamber water does not allow for mixing with the bottom waters. In contrast, because the mass balance method relies on water column data, results are affected by mixing and biogeochemical reactions that can remove metals from the water column; thus, flux estimates using this method likely reflect minimum values. However, when used together, these two methods provide a useful tool for constraining metal fluxes under different redox conditions and highlight the importance of measuring ORP in addition to DO. The results of this study can be used by water utilities to improve the effectiveness of engineered oxygenation systems and water quality management practices related to iron and manganese. / Master of Science / In many drinking water reservoirs, elevated concentrations of metals, such as iron (Fe) and manganese (Mn), pose a challenging water quality problem. Elevated metal concentrations affect taste, color, and odor in drinking water and can be expensive to treat for. The presence of Fe and Mn in water is influenced by the oxygen concentrations in the water. When oxygen levels in the water are high, Fe and Mn are not soluble in water. However, when the oxygen levels in water are low, Fe and Mn can be released from soils, sediments and rocks into water and can thus pose a concern for drinking water quality. Many water utilities have installed systems to increase oxygen concentrations in drinking water reservoirs with the goal of maintaining low levels of metals in water supplies. However, previous research has shown that even when oxygenation systems are operational, Fe and Mn can still be released into water from the reservoir’s bottom sediments. To examine the factors that contribute to the release of metals from the sediments into the water column, I measured the rate of release of Fe and Mn from the sediments into the water column at a local drinking water reservoir (Falling Creek Reservoir, Vinton, VA). I conducted the experiments twice during summer 2018 using chambers that isolated the water immediately above the sediments. During the experiments, I monitored how Fe and Mn concentrations changed over time under different oxygen conditions. In addition to the measurements, I also used a mass balance method using water column data to estimate the metal release. Overall, results showed that release rates are highly variable during the summer months, with some periods having positive rates (releasing metals from sediments into the water column) and some with negative rates (returning metals from the water column to sediment). The metal release rate are highly sensitive to oxygen conditions in the water column, at the sediment-water interface and in the sediments. When used together, these two methods provide a useful tool for constraining metal release rates under different oxygen conditions. This research will help drinking water plant managers to improve the effectiveness of oxygenation systems and water quality management practices related to Fe and Mn. Additionally, this research will help improve the water quality for residents and can be applied to other lakes and reservoirs where metal concentrations are elevated.

Os reservatórios, por serem corpos de água dinâmicos e pelos seus usos múltiplos, sofrem acelerado processo de eutrofização. Neste estudo avaliou-se a atual condição da represa do Lobo (municípios de Brotas e Itirapina, SP) em relação a algumas características físicas, químicas e biológicas em uma perspectiva temporal. As amostragens foram realizadas em duas épocas representativas das estações seca e chuvosa, compreendidas no período de setembro de 2000 e junho de 2001. Foram estabelecidos seis pontos de coleta, nos quais foram coletadas amostras de água para análises de nutrientes, clorofila, material em suspensão, zooplâncton e foram também realizadas medidas \"in situ\" de variáveis físicas e químicas, com o multisensor Horiba U10. Os resultados obtidos revelaram que ocorreram variações sazonais de moderada amplitude, caracterizando dois períodos: o seco com temperaturas menores, águas mais oxigenadas, menor condutividade elétrica e maiores concentrações de nutrientes. O zooplâncton da represa do Lobo foi numericamente dominado pelos rotíferos, seguidos pelos cladóceros e copépodos em proporções bem menores, similarmente ao reportado pelos estudos anteriores, indicando que em nível de grandes grupos não houve ainda uma mudança na estrutura desta comunidade. As variações na densidade dos principais grupos zooplanctônicos estão relacionadas às características físicas e químicas das diferentes porções da represa (com maiores densidades na porção superior, mais eutrófica) e à sazonalidade, com maior abundância de rotíferos no período chuvoso e maiores densidades de protozoários e microcrustáceos no inverno. Durante o período de estudo a condição trófica do reservatório foi mesotrófica, contudo com níveis de nutrientes e biomassa do fitoplâncton, indicada pela concentração de clorofila, superiores aos níveis reportados para a década de 1970. Concluiu-se portanto que a represa está sofrendo um processo de eutrofização. / Reservoirs, being dynamic bodies of water and for their several uses, undergo an accelerated process of eutrophication. The aim of this research is to analyze the actual condition of the Lobo reservoir (Itirapina and Brotas districts, SP) in relation to some physical, chemical and biological characteristics in a temporal perspective. Sampling was made in two representative periods of both dry and rainy seasons, during the period of September 2000 and June 2001. Six sampling stations where established for the analysis of nutrients, chlorophyll, suspended material, zooplankton, and also some \"in situ\" measurements utilizing a Horiba U10 multisensor where taken at these same locations for the observation of some chemical and physical variables. The results revealed the occurrence of seasonal variations of moderate magnitude, putting in evidence two periods: a dry one with low temperatures, more oxygenated water, lower electrical conductivity and lower nutrient concentrations in opposition with a rainy season, that was identified by higher temperatures, lower dissolved oxygen concentrations, higher electrical conductivity and higher concentrations of nutrients. The zooplankton of Lobo reservoir was numerically dominated by rotifers, followed by cladocerans and copepods in lower abundances, as similarly reported by previous studies, showing that in terms of the major groups there still was no shift in the community structure. Variations in the density of the main zooplankton groups were related to the physical and chemical characteristics of the different parts of this reservoir (with higher densities in the upper portion, that was more eutrophicated) and due to the seasonality, with higher abundance of rotifers in the rainy season and bigger densities of protozoans and microcrustaceans in the winter. Throughout the period of study the trophic condition of the reservoir was mesotrophic, although with levels of nutrients and phytoplankton biomass, indicated by the concentration of chlorophyll, higher than those reported during the 70\'s. It was concluded that the reservoir is undergoing a slow eutrophication process.

Shihmen Reservoir has contributed to the economic development of northern Taiwan since it was built in 1964. As result of natural disasters and improper development, Shihmen Reservoir had a big problem with sediment deposition. To solve this problem, government executed the first stage of integrated treatments planning on Shihmen Reservoir.The period of program is from 2006 to 2008 and divided into three parts. From the government point of view, this study recognized the use of agriculture water¡Nindustrial water¡Ndomestic water¡Nelectricity generation¡Ntourism and decreased sediment extraction expense as benefit index ¡F recognized budgets and natural disasters as cost index to evaluate the effect of this program.The value of benefit-cost ratio before integrated treatments is 2.817 and the value of benefit-cost ratio after integrated treatments is 3.566. The value of benefit-cost ratio after integrated treatments is bigger than the value of benefit-cost ratio before integrated treatments.It means that it is workable for this program. Considering the reason that the water rate and utility bills are much cheaper in Taiwan, this study adjust the rate of water and utility individually. With the adjustment of water rate, the value of benefit-cost ratio before integrated treatments is 3.519 and the value of benefit-cost ratio after integrated treatments is 4.31. With the adjustment of utility rate, the value of benefit-cost ratio before integrated treatments is 3.689 and the value of benefit-cost ratio after integrated treatments is 4.074. It is also beneficial for this program.