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Thesis (Ph.D.)--Aberdeen University, 2008. / Includes bibliographical references.

Sanitary hot water production contributes significantly to the electrical energy consumption in the university campus. An in-depth understanding of the current hot water technology, number of students, capacity of water used per student, time of use of hot water, total volume of hot water consumed and the total energy used on an average weekday in a university residence are very crucial in opting for energy efficient technology like an air source heat pump (ASHP) water heater. The study focused on quantitative and qualitative analysis of data collected for the hot water profiles in one of the university residences (Elitheini 1) from the conduction of experiment and questionnaires. The results revealed that 94% of the 75 students used hot water during the Eskom morning peak and 61% during the Eskom evening peak. In addition, the average daily energy consumption of the 12 kW Calorifier was 139.49 kWh, while the measured volume of hot water usage was 1950 L which is in strong agreement with the total volume (1945 L) of hot water consumption from the questionnaires. The p-value of the average volume of hot water usage measured by experiment and questionnaires was 0.7 and is of no mean significant difference. The monthly energy consumption for the week days was projected to be 2929.31 kWh. By retrofitting of calorifier with an ASHP unit, the energy consumption could reduce to 976.43 kWh based on its consecutive coefficient of performance of 3. Finally, from the energy consumption reduction analysis and the current Eskom tariffs, it can be alluded that the payback period of the proposedASHP unit as a retrofit to the calorifier is going to be less than 2 years and is worthy to invest into such technology under this study due to its favourable payback period and the reliability and lifespan of the ASHP unit.

The principal aim of this thesis was to investigate the effects of altering the energy density of the diet (kJ/g) on post-restriction weight regain in domestic cats and laboratory mice. Secondly, evidence for body weight regulation was examined in mice. In cats, consumption of the same number of calories of a low energy dense diet (with added water) induced significantly less weight rebound than a more energy dense diet (with no added water). This was accounted for by differences in physical activity, as cats on the low energy dense diet were significantly more active. It was assumed the less energy dense diet held cats in a perceived state of energy restriction and they were actively searching for more food. In mice, cellulose was used to alter the energy density of the diet. Post-restriction body weight rebound was also observed on an energy dense diet (no cellulose). However, body weight not did reach pre-restriction levels when consuming a low energy dense diet (with added cellulose) and digestibility was significantly reduced. It was likely that the fibre-rich induced a gut processing limit on the bulk of digestible food that could be consumed. Overall, the energy density of the diet was shown to modulate post-restriction body weight rebound, but results varied with species and the energy dilutant used. The implications for human weight management have yet to be elucidated. The second principle finding was that post-restriction hyperphagia was induced to replenish food deficiencies incurred during caloric restriction, rather than to replenish body mass loss in mice. This provided preliminary evidence for a ‘calorie-counting’ body weight regulatory system in mammals.

Nicotine, the major psychoactive ingredient of tobacco smoke, underlies numerous effects by activating neuronal nicotinic acetylcholine receptors. Both in vitro and in vivo studies suggest that nicotine is neuroprotective and improves cognitive performance. Epidemiology studies show that smoking is negatively correlated with the incidence of Parkinson's disease and Alzheimer's disease. Postmortem research and neuroimaging studies show that loss of nicotinic binding sites in the brain is the major feature of neurodegenerative diseases related to dementia and cognitive impairment. Caloric restriction, a regimen that extends the lifespan in all mammalian species studied so far including rodents and primates, is a highly regulated response to food deprivation. It is believed that the longevity effect of caloric restriction is mediated by SIRT1, a NAD-dependent deacetylase, and its related genes. Nicotine's effect on body weight could also lead to weight loss by decreasing caloric absorption consumption. The goal of this study was to find the possible correlation between nicotine's effects and the activation of SIRT1 and its related genes. Using beta2-/- mice that lack high affinity beta2 nicotinic acetylcholine receptors (nAChRs), we first demonstrated that beta2* nAChRs do not directly regulate expression of survival genes. However, we found that loss of beta2* nAChRs could result in augmented cellular stress, which indirectly increased expression of SIRT1, Nampt, and Ku70, possibly as an adaptive response to provide protection against neurodegeneration. We also found that loss of endogenous activation of beta2* nAChRs had less effect on synaptic connections but strongly impaired survival of hippocampal GABAergic neurons. To activate beta2* nAChRs in normal mice, we administered nicotine through drinking water. In a short-term exposure study, we determined the dose of nicotine to be used in young adult mice, and found that chronic nicotine treatment was anxiolytic, decreased caloric consumption, increased nAChR binding sites, and most importantly, increased expression of SIRT1 and its related genes. Finally, we compared long-term nicotine treatment with caloric restriction in middle-aged mice to examine their effects to brain aging, and our results indicated that in mice long term caloric restriction and nicotine treatment both tend to improve memory in aging mice, but appear to act through different mechanisms.

In the summer of 2003, David Cutler, Edward Glaeser, and Jesse Shapiro published the paper, “Why Have Americans Become More Obese?”1 In the paper, the authors explore changing trends in American weight and caloric intake over time and hypothesize as to the potential causes of these changes. In performing our tests, we hope to both replicate their results and update any analysis for the present.

Submitted by Lucas Cesar Gomes Squillante null (lucasquillante@hotmail.com) on 2018-01-19T17:39:44Z No. of bitstreams: 1 Dissertação de Mestrado Lucas Cesar Gomes Squillante.pdf: 13112928 bytes, checksum: b4a4e7a0bc1cbdc48db3b829714e912d (MD5) / Approved for entry into archive by Ana Paula Santulo Custódio de Medeiros null (asantulo@rc.unesp.br) on 2018-01-22T13:15:43Z (GMT) No. of bitstreams: 1 squillante_lcg_me_rcla.pdf: 13113103 bytes, checksum: ee63e961b931fa78df69438fc268b5f2 (MD5) / Made available in DSpace on 2018-01-22T13:15:43Z (GMT). No. of bitstreams: 1 squillante_lcg_me_rcla.pdf: 13113103 bytes, checksum: ee63e961b931fa78df69438fc268b5f2 (MD5) Previous issue date: 2017-11-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O fenômeno da supercondutividade atualmente um dos mais relevantes tópicos na Física da Matéria Condensada, tornando os sistemas fortemente correlacionados um tópico de grande interesse devido à possibilidade de estudar os aspectos fundamentas da interação elétron-elétron, que são o âmago da supercondutividade. Desta forma, a classe de condutores moleculares (TMTTF)2X (onde TMTTF é tetrametiltetratiafuvaleno e X é um contra-ânion) desempenha um papel sistemático e fundamental no estudo de tais aspectos de correlação. Nesta tese de mestrado, os materiais de interesse foram o (TMTTF)2PF6-H12 e o (TMTTF)2PF6-D12, onde uma anomalia na constante dielétrica diferente para os dois sais foi observada na transição ferroelétrica de Mott-Hubbard através de medidas de constante dielétrica quasi-estática no eixo c* (contribuição iônica) e o comportamento tipo relaxor da variante hidrogenada foi analisado com base na teoria de campo médio. Uma revisão de transições de fase clássicas e quânticas também foi realizada com o objetivo de estudar o chamado efeito magneto-calórico para o modelo do paramagneto de Brillouin (o parâmetro de Grüneisen magnético), que é uma grandeza Física única e poderosa para detectar experimentalmente uma transição de fase quântica induzida por campo magnético em um sistema real. Ainda, um estudo comparativo entre as fases delta (hexagonal) e delta' (tetragonal) da liga binária FeSe1-x foi realizado e monocristais foram sintetizados utilizando o método de síntese de estado sólido visando atingir a fase delta. / The phenomenon of superconductivity is currently one of the most relevant topics in Solid State Physics, making strongly correlated systems a very highattractive topic due to the possibility of studying the fundamental aspects of the electron-electron interaction that are the core of superconductivity. Thus, the class of molecular conductors (TMTTF)2X (where TMTTF is tetramethyltetrathiafuvalene and X is a counter-anion) plays a systematic and fundamental role to study such correlation aspects. In this Master Thesis, the materials of interest were the (TMTTF)2PF6-H12 and (TMTTF)2PF6-D12, where a different dielectric anomaly at the Mott-Hubbard ferroelectric transition was observed for the two salts and the relaxor behavior of the hydrogenated variant was analysed based on the mean-field theory. A review of classical and quantum phase transitions was performed aiming to study the so-called magneto-caloric effect (the magnetic Grüneisen parameter) for the Brillouin paramagnet model, which is a powerful and unique physical quantity to experimentally detect a quantum phase transition induced by magnetic field in a real system. Also, a comparative study between the (hexagonal) and (tetragonal) phases of the binary alloy FeSe1-x was performed and single-crystals were synthesized employing the solid-state reaction method in order to achieve the phase.

Call number: LD2668 .T4 1956 G53 / Master of Science

Background: While the provision of adequate nutrition support in critically ill patients has been shown to have an impact on short-term clinical outcomes, relatively little is known about subsequent long-term outcomes. We aimed to examine the association between nutritional adequacy and long-term outcomes including survival and health-related quality of life (HRQoL) in critically ill patients requiring prolonged mechanical ventilation. Methods: The study was conducted as a retrospective cohort study on data collected prospectively in the context of a multicenter randomized controlled trial (RCT) in critically ill patients. Randomized patients who stayed in the intensive care unit (ICU) and were mechanically ventilated for >8 days were eligible for the study, but only six-month survivors were considered for the assessment of HRQoL. Nutritional adequacy was obtained from the average proportion of prescribed calories received during the first eight days of mechanical ventilation in the ICU. Survival status and HRQoL as assessed using Short-Form 36 Health Survey (SF-36) were obtained prospectively as part of the RCT protocol at three-months and six-months post ICU admission. Results: Of the 1223 patients enrolled in the randomized controlled trial, 475 met the inclusion criteria for this study. At six-month follow-up, 302 of the 475 patients were alive. Among critically ill patients with >8 days of mechanical ventilation in the ICU, survival time in those who received low nutritional adequacy was significantly shorter than for those who received high nutritional adequacy after adjusting for important covariates. Among six-month survivors, clinically meaningful and statistical significant associations between increase in scores of Physical Functioning (PF) and Role Physical domains (RP) of the SF-36 and 25% increase in nutritional adequacy were observed at three-months follow-up. No significant associations were observed at six-months. Conclusions: Our findings suggest that nutritional adequacy received as early as the first week in the ICU seems beneficial to longer survival time and faster physical recovery post ICU discharge in critically ill patients requiring prolonged mechanical ventilation in the ICU. Well-designed randomized controlled trials are needed to provide stronger assessment of the causal impact of nutrition therapy on long-term outcomes. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2013-09-28 21:31:40.064

Human (h) growth hormone (GH) levels decline rapidly in response to excess caloric intake before there is any evidence of obesity. In this thesis, the mechanism underlying this response was examined by manipulating levels of caloric intake and physical activity at the levels of gene expression and chromosomal structure. Transgenic mice containing the intact hGH locus were used as a model system. Briefly, the findings are: (I) High caloric intake (high fat diet) for three days resulted in hyperinsulinemia and a decrease in both hGH synthesis and secretion. (II) Incorporation of physical activity (swim) muted the effects of excess caloric intake on insulin levels as well as hGH production. (III) Human GH RNA accumulation was shown for the first time to be negatively regulated by insulin in pituitary cultures, and (IV) an enhancer box (E-box) DNA element was implicated in this response. (V) Induction of the E-box associated transcription factor HIF-1α with insulin significantly decreased hGH RNA levels, and was accompanied by recruitment of HIF-1α to the hGH gene (hGH) promoter in situ. (VI) Both a reduction in HIF-1α synthesis and HIF-1 DNA binding blunted the negative effect of insulin on hGH RNA levels. (VII) The hGH response to insulin was associated with a decrease in histone H3/H4 hyperacetylation in the proximal hGH promoter region. The same pattern of chromatin remodelling was observed in pituitary cells in vivo in response to excess caloric intake. (IX) Increased recruitment of nuclear receptor co-repressor and decreased association of RNA polymerase II were also observed. Collectively, these effects are consistent with reduced hGH promoter function. (X) This reduction by excess caloric intake was also consistent with changes in the three dimensional-structure of the hGH locus including detected loss of physical interaction between hGH enhancer and promoter regions. (XI) By contrast, physical activity combined with the high caloric intake preserved the chromosomal structure of the hGH locus. These observations are discussed in relation to a physiological requirement for rapid control of hGH levels in response to energy homeostasis, as well as the molecular basis governing this process. / May 2015