985 resultados para Heavy water reactors


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Toxoplasma gondii transmission via breastfeeding has been discussed; however, no cases have been confirmed to date. This article describes a case of acute toxoplasmosis diagnosed in a mother and her six-month-old breastfed infant. The study accounts for the possibility of breast milk transmission and directs both clinicians and pediatricians to the hypothesis that both patients acquired toxoplasmosis via water ingestion.

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Objective:We aimed to identify if there was any difference in Levonorgestrel-releasing intrauterine system (LNG-IUS) efficacy or weight gain when used in heavy menstrual bleeding (HMB) treatment, between obese and non-obese women. Population and methods: This was a case-controlled retrospective study undertaken between 2002-2007. 194 women with HMB were treated with LNG-IUS and stratified into two groups accordingly with body mass index (BMI): Obese Group – BMI ≥ 30 (n=53) and Non-obese Group – BMI < 30 (n=141). Age, weight, days of spotting and days of menses were analyzed at 1, 3 and 6 months after insertion and then annually until 2 years. Analytic parameters of anemia (hemoglobin, serum ferritin, mean corpuscular volume) were reviewed at pre-insertion, at 6 months and then annually until 2 years. Results: During the 2-year follow-up there was a similar improvement in two groups regarding duration of menses, spotting and in analytic parameters of anemia. A statistically significant improvement was observed in obese group after 2 years of treatment regarding analytic parameters of anemia and menstrual characteristics, without weight gain. Conclusion: In obese women, the LNG-IUS is an effective treatment for heavy menstrual bleeding, without being associated to weight gain.

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Dissertação para a obtenção do grau de doutor em Biologia pelo Instituto de Tecnologia Química e Biológica. Universidade Nova de Lisboa

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The use of leaves for drinking water is a widespread tool-use behavior among chimpanzees. Although this tool-use behavior is widely described as the use of leaf sponges, it can actually be found in three different forms: leaf sponges, leaf-folding, and leaf spoons. Among the chimpanzee community of Bossou, we can observe all three forms, albeit in different frequencies. Here I describe the longitudinal record of manufacture and use of leaf tools for drinking water, highlighting the learning process underlying the acquisition of the skill. The degree of laterality evident in both immature and mature performers is also presented here. The use of leaves for drinking water emerges at the age of 1.5 years old, but the manufacture of leaf tools only starts at 3.5 years of age. Infants and juveniles were observed to use drinking tools that had been discarded by other individuals after use. Concerning handedness in general, the chimpanzees are ambidextrous, with some individuals biased to one side.

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The effect of an 8 hour-period of water deprivation on fluid and electrolyte renal excretion was investigated in male Wistar rats infected with the strain São Felipe (12SF) of Trypanosoma cruzi, in comparison with age and sex matched non-infected controls. The median percent reductions in the urinary flow (-40% v -63%) and excretion ofsodium (-57% v-79%) were smaller in chagasic than in control rats, respectively. So, chagasic rats excreted more than controls. On the other hand, the median percent decrement in the clearance of creatinine was higher in chagasic (-51%) than in controls (-39%). Thus, chagasic rats showed some disturbed renal hydroelectrolytic responses to water deprivation, expressed by smaller conservation, or higher excretion of water and sodium in association with smaller glomerularfiltration rate. This fact denoted an elevation in the fractional excretion of sodium and water.

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Dissertation for the Master degree in Biotechnology

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Dissertação para obtenção do grau de Mestre em Biotecnologia

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Dissertação para obtenção do Grau de Mestre em Engenharia do ambiente, perfil de engenharia sanitária

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

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The purpose of this study was to identify parents and obtain segregating populations of cowpea (Vigna unguiculata L. Walp.) with the potential for tolerance to water deficit. A full diallel was performed with six cowpea genotypes, and two experiments were conducted in Teresina, PI, Brazil in 2011 to evaluate 30 F2 populations and their parents, one under water deficit and the other under full irrigation.

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Dissertation presented to obtain the Ph.D degree in Engineering and Technology Sciences, Chemical Engineering.

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Dissertação para obtenção do Grau de Mestre em Tecnologia e Segurança Alimentar

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Water is a limited resource for which demand is growing. Contaminated water from inadequate wastewater treatment provides one of the greatest health challenges as it restricts development and increases poverty in emerging and developing countries. Therefore, the connection between wastewater and human health is linked to access to sanitation and to human waste disposal. Adequate sanitation is expected to create a barrier between disposed human excreta and sources of drinking water. Different approaches to wastewater management are required for different geographical regions and different stages of economic governance depending on the capacity to manage wastewater. Effective wastewater management can contribute to overcome the challenges of water scarcity. Separate collection of human urine at its source is one promising approach that strongly reduces the economic and load demands on wastewater treatment plants (WWTP). Treatment of source-separated urine appears as a sanitation system that is affordable, produces a valuable fertiliser, reduces pollution of water resources and promotes health. However, the technical realisation of urine separation still faces challenges. Biological hydrolysis of urea causes a strong increase of ammonia and pH. Under these conditions ammonia volatilises which can cause odour problems and significant nitrogen losses. The above problems can be avoided by urine stabilisation. Biological nitrification is a suitable process for stabilisation of urine. Urine is a highly concentrated nutrient solution which can lead to strong inhibition effects during bacterial nitrification. This can further lead to process instabilities. The major cause of instability is accumulation of the inhibitory intermediate compound nitrite, which could lead to process breakdown. Enhanced on-line nitrite monitoring can be applied in biological source-separated urine nitrification reactors as a sustainable and efficient way to improve the reactor performance, avoiding reactor failures and eventual loss of biological activity. Spectrophotometry appears as a promising candidate for the development and application of on-line nitrite monitoring. Spectroscopic methods together with chemometrics are presented in this work as a powerful tool for estimation of nitrite concentrations. Principal component regression (PCR) is applied for the estimation of nitrite concentrations using an immersible UV sensor and off-line spectra acquisition. The effect of particles and the effect of saturation, respectively, on the UV absorbance spectra are investigated. The analysis allows to conclude that (i) saturation has a substantial effect on nitrite estimation; (ii) particles appear to have less impact on nitrite estimation. In addition, improper mixing together with instabilities in the urine nitrification process appears to significantly reduce the performance of the estimation model.

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The development of devices based on heterostructured thin films of biomolecules conveys a huge contribution on biomedical field. However, to achieve high efficiency of these devices, the storage of water molecules into these heterostructures, in order to maintain the biological molecules hydrated, is mandatory. Such hydrated environment may be achieved with lipids molecules which have the ability to rearrange spontaneously into vesicles creating a stable barrier between two aqueous compartments. Yet it is necessary to find conditions that lead to the immobilization of whole vesicles on the heterostructures. In this work, the conditions that govern the deposition of open and closed liposomes of 1.2-dipalmitoyl-sn-Glycero-3-[Phospho-rac-(1-glycerol)] (sodium Salt) (DPPG) onto polyelectrolytes cushions prepared by the layer-by-layer (LbL) method were analyzed. Electronic transitions of DPPG molecules as well as absorption coefficients were obtained by vacuum ultraviolet spectroscopy, while the elemental composition of the heterostructures was characterized by x-ray photoelectron spectroscopy (XPS). The presence of water molecules in the films was inferred by XPS and infrared spectroscopy. Quartz crystal microbalance (QCM) data analysis allowed to conclude that, in certain cases, the DPPG adsorbed amount is dependent of the bilayers number already adsorbed. Moreover, the adsorption kinetics curves of both adsorbed amount and surface roughness allowed to determine the kinetics parameters that are related with adsorption processes namely, electrostatic forces, liposomes diffusion and lipids re-organization on surface. Scaling exponents attained from atomic force microscopy images statistical analysis demonstrate that DPPG vesicles adsorption mechanism is ruled by the diffusion Villain model confirming that adsorption is governed by electrostatic forces. The power spectral density treatment enabled a thorough description of the accessible surface of the samples as well as of its inner structural properties. These outcomes proved that surface roughness influences the adsorption of DPPG liposomes onto surfaces covered by a polyelectrolyte layer. Thus, low roughness was shown to induce liposome rupture creating a lipid bilayer while high roughness allows the adsorption of whole liposomes. In addition, the fraction of open liposomes calculated from the normalized maximum adsorbed amounts decreases with the cushion roughness increase, allowing us to conclude that the surface roughness is a crucial variable that governs the adsorption of open or whole liposomes. This conclusion is fundamental for the development of well-designed sensors based on functional biomolecules incorporated in liposomes. Indeed, LbL films composed of polyelectrolytes and liposomes with and without melanin encapsulated were successfully applied to sensors of olive oil.