1000 resultados para Isótopos de oxigênio
Resumo:
Pós-graduação em Ciências da Motricidade - IBRC
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Pós-graduação em Química - IQ
Resumo:
Pós-graduação em Cirurgia Veterinária - FCAV
Resumo:
Pós-graduação em Zootecnia - FMVZ
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
After the isolation of Helicobacter pylori from an injury at the stomach mucosa by Marshall and Wareen, work that was recognized with the Nobel Prize of Medicine or Physiology in 2005, many other works showed the relationship between the presence of H. pylori and diseases at the digestive system, such as gastritis, gastric, duodenal and peptic ulcer, and stomach cancer. The 13C-Urea Breath Test - 13C-UBT is a non-invasive diagnostic method that utilizes the breath of a patient to determine the presence of H. pylori through stable isotopes. This work aimed to find an ideal 13C-UBT Isotopic Ratio Mass Spectroscopy cut-off value (a threshold between positive and negative) to diagnose H. pylori infection at Brazilian population. Patients were selected at the UNESP-Botucatu Clinical Hospital Endoscopy Section. With these results it was possible to indicate that the best cut-off value is between 2.5 to 6 ‰ of Delta Over Baseline (DOB)
Resumo:
The use of stable isotopes in Brazil is being improved, mainly through research conducted at main universities in the country. Some applications in health allow to studying, for example, processes involving synthesis and protein degradation, energy expenditure, body composition, kinetics of vitamins, mineral absorption and diagnose diseases related to Helicobacter pylori. The big motivation is to encourage the growth of investments in health in the few centers that have mass spectrometers in Brazil, as the technique is harmless to humans, in other words, no has problems to use it like when you use radioactive isotopes
Resumo:
The deslignification with oxygen, also denominated pre-O2, consists in a whitening stage, which consists of accomplishing an oxidation of the lignin, and remove it with the alkali, providing a larger earnings in the bleaching of the pulp. The pre-O2 is a process already very established, where a significant part of the cellulose of whitened short fiber produced nowadays suffers deslignification for this method. The conditions of work of this stage contemplate directly in the results of the deslignification level, in the physical, optical and mechanics properties of the pulp, and consequently of the paper, because this is important to know their effects fully. The main variables related to the control of this process are respectively: pressure and oxygen load, alkaline load, consistence, time and temperature, being this last variable was the study focus in this work. The objective of the work was to analyze the effect of the variation of the temperature in the oxygen whitening along every bleaching process of the pulp, refine and in the optical, physics and mechanics properties of the paper. The development of the work was based in four temperature levels (90, 95, 100 and 105°C) combined to two whitening sequences (OD0(E+P)D1P and OAHTD0(E+P)D1P). The results obtained in the oxygen deslignification stage indicated that the elevation of the temperature contemplated in increases of the whiteness, deslignification efficiency and in the viscosity loss allied to the reduction of the selectivity of the process. In the remaining of the whitening, the sequence that included the acid hydrolysis presented values slightly inferior of whiteness, kappa number, viscosity and yield in relation to the other sequence when compared with the samples of same temperatures. Already the physical tests showed that the sequence with acid stage amplifies the values of capillary... (Complete abstract click electronic access below)
Resumo:
This work aimed to develop a biological system for removal of ammonia nitrogen operating at low concentrations of dissolved oxygen. Thus, a biological upflow vertical reactor was built, in which the affluent pass through the support media until the top. Sludge from an anaerobic stabilization pond of a slaughterhouse unit in the city of Presidente Prudente - SP was used as inoculum. Initially the system operated in batch and afterwards in a continuous flow with different HRT. For feeding the reactor, an initial phases was adopted a synthetic culture media, described by Martins (2007), in order to establish the ideal conditions for the development of Anammox bacteria and subsequently, submitted to the system a slugde effluent of slaughterhouse. The results showed significant removal efficiency of N-NH4+, especially in the phase without recirculation of culture media, with an average of 71% removal, with the proportion of removal of N-NH4 +:N-NO2- average 1: 1,69. For the period of operation with effluent from the slaughterhouse, were not obtained satisfactory results, without confirmation of the proliferation of Anammox bacteria in the system, due to the high presences of organic matter in the same confirmed by high concentrations of COD
Resumo:
Mass spectrometry is an analytical technique widely used in several areas of academic research. It allows the knowledge of the information about the micro-world of atoms leading to significant advances in science today. The analysis of stable isotopes of carbon, hydrogen, oxygen, nitrogen and sulfur, also known as bio-elements, shows itself as a major area of interest in using the proposed method. The development of techniques and equipment coupled with mass spectrometry promises to deliver even greater progress in this field, in particular, for the biological sciences and related areas. The pyrolytic method in reduction of organic compounds at high temperatures provides simultaneous isotopic analysis of bio-elements H and O, by the gases released, H2 and CO after the pyrolitic process, significantly reducing analysis time and the amount of material to sample. This paper presents a review of mass spectrometry with its basic principles of operation, and pyrolytic method for reducing compounds at temperatures above 1400 ° C for isotopic analysis of bio-elements
Resumo:
The aim of this study was to investigate whether aerobic capacity (VO2max) would be modified by antihypertensive therapy in elderly and middle-age women after 12 weeks of exercise training. The volunteers were divided in two groups: normotensive (n=14) and hypertensive (n=14). Aerobic exercise was performed for 3 days/week, during 60 minutes, for 12 weeks with an intensity of 50-70% rest heart hate. Anthropometric parameters (weight and height), body fat index, % of fat mass, cardiopulmonary evaluation to calculated VO2max and a cardiovascular evaluation with blood pressure and rest heart hate were evaluated at baseline and after training program. At the end of study abdominal circumference and Borg scale were also evaluated. Our findings showed the aerobic program of 12 weeks was effective to reduce diastolic blood pressure in both groups. Systolic blood pressure was reduced only hypertensive group. No evidences were found the aerobic capacity was affected by hypertensive therapies. In conclusion, the aerobic program for 12 weeks was effective to reduce blood pressure and there was no influence of antihypertensive therapy on the aerobic capacity in this particular population.
Resumo:
O glicerol é um importante subproduto de processos fermentativos. Em algumas bebidas alcoólicas, como vinhos e vodcas contribuem com seu sabor tornando-a aceitável para o consumidor. Com o incentivo na produção de biocombustíveis, a disponibilidade do glicerol deve aumentar, já que é o principal subproduto gerado na produção do Biodiesel. A sua presença em alguns alimentos, pode identificar presença de microrganismos, já que pode ser uma fonte de carbono para eles. Devido às inúmeras utilizações do glicerol para diversos tipos de indústrias, a dosagem do glicerol se torna cada vez mais importante e rotineira. Isso incentiva novas pesquisas de métodos de doseamento. A enzima GK é presente em vários microrganismos e converte o glicerol em glicerol-3-fosfato. Com a utilização da enzima Glicerol -3- fofato desidrogenase, o glicerol - 3 – fosfato é convertido a di-hidroxi-acetona fosfato com a produção de NADH. Este pode ser quantificado através do espectrofotômetro, tornando-se um rápido e eficiente método para doseamento. A levedura recombinante Pichia pastoris foi escolhida pois foi inserida no seu DNA, o Gene GUT1 que expressa a GK em Saccharomyces cerevisiae. Além disso, a expressão enzimática é extracelular, diminuindo etapas no processo de isolamento da enzima GK. O trabalho consistiu em otimizar a produção de GK expressa pela levedura recombinante Pichia pastoris por meio da adição de oxigênio no biorreator de fermentação em escala de 2,5 L. Os resultados do presente estudo indicam o ponto ótimo de oxigenação em fermentador nos parâmetros estabelecidos é de 2,0 lpm tanto para a produção de enzimática quanto para biomassa formada
Resumo:
Devido a grande demanda do uso da energia atômica, as pesquisas sobre o processo de separação de isótopos tornam-se cada vez mais importantes. Neste trabalho mostramos uma técnica de separação de isótopos usando o efeito da ressonância.