956 resultados para LOW-VOLUME VENTILATION
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Compared to other volatile carbonylic compounds present in outdoor air, formaldehyde (CH2O) is the most toxic, deserving more attention in terms of indoor and outdoor air quality legislation and control. The analytical determination of CH2O in air still presents challenges due to the low-level concentration (in the sub-ppb range) and its variation with sampling site and time. Of the many available analytical methods for carbonylic compounds, the most widespread one is the time consuming collection in cartridges impregnated with 2,4-dinitrophenylhydrazine followed by the analysis of the formed hydrazones by HPLC. The present work proposes the use of polypropylene hollow porous capillary fibers to achieve efficient CH2O collection. The Oxyphan (R) fiber (designed for blood oxygenation) was chosen for this purpose because it presents good mechanical resistance, high density of very fine pores and high ratio of collection area to volume of the acceptor fluid in the tube, all favorable for the development of air sampling apparatus. The collector device consists of a Teflon pipe inside of which a bundle of polypropylene microporous capillary membranes was introduced. While the acceptor passes at a low flow rate through the capillaries, the sampled air circulates around the fibers, impelled by a low flow membrane pump (of the type used for aquariums ventilation). The coupling of this sampling technique with the selective and quantitative determination of CH2O, in the form of hydroxymethanesulfonate (HMS) after derivatization with HSO3-, by capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-(CD)-D-4) enabled the development of a complete analytical protocol for the CH2O evaluation in air. (C) 2008 Published by Elsevier B.V.
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A Scots pine (Pinus sylvestris) progeny trial was established in 1990, in the southwestern part of Sweden. The offspring was from 30 plus trees. The trial is located on abandoned agricultural land and has a single tree block design with a variation in spacing. The trial has been damaged by voles. At a tree age of ten years, growth, damages and branch properties were estimated. An analysis of variance on height, diameter and stem volume shows significant difference between spacing and progenies as well as interactions between these factors. As indicated by a better annual height increment and fewer and thinner branches at each whorl the densest spacing has the highest potential to produce quality logs.There were also differences between progenies in growth and quality traits. Some progenies combined good growth and branch characters with low mortality, straight stems and few damages. Other progenies had superior volume production.
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A ventilation radiator is a combined ventilation and heat emission unit currently of interest due to its potential for increasing energy efficiency in exhaust ventilated buildings with warm water heating. This paper presents results of performance tests of several ventilation radiator models conducted under controlled laboratory conditions. The purpose of the study was to validate results achieved by Computational Fluid Dynamics (CFD) in an earlier study and indentify possible improvements in the performance of such systems. The main focus was on heat transfer from internal convection fins, but comfort and health aspects related to ventilation rates and air temperatures were also considered. The general results from the CFD simulations were confirmed; the heat output of ventilation radiators may be improved by at least 20 % without sacrificing ventilation efficiency or thermal comfort. Improved thermal efficiency of ventilation radiators allows a lower supply water temperature and energy savings both for heating up and distribution of warm water in heat pumps or district heating systems. A secondary benefit is that a high ventilation rate can be maintained all year around without risk for cold draught.
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With the building sector accounting for around 40% of the total energy consumption in the EU, energy efficiency in buildings is and continues to be an important issue. Great progress has been made in reducing the energy consumption in new buildings, but the large stock of existing buildings with poor energy performance is probably an even more crucial area of focus. This thesis deals with energy efficiency measures that can be suitable for renovation of existing houses, particularly low-temperature heating systems and ventilation systems with heat recovery. The energy performance, environmental impact and costs are evaluated for a range of system combinations, for small and large houses with various heating demands and for different climates in Europe. The results were derived through simulation with energy calculation tools. Low-temperature heating and air heat recovery were both found to be promising with regard to increasing energy efficiency in European houses. These solutions proved particularly effective in Northern Europe as low-temperature heating and air heat recovery have a greater impact in cold climates and on houses with high heating demands. The performance of heat pumps, both with outdoor air and exhaust air, was seen to improve with low-temperature heating. The choice between an exhaust air heat pump and a ventilation system with heat recovery is likely to depend on case specific conditions, but both choices are more cost-effective and have a lower environmental impact than systems without heat recovery. The advantage of the heat pump is that it can be used all year round, given that it produces DHW. Economic and environmental aspects of energy efficiency measures do not always harmonize. On the one hand, lower costs can sometimes mean larger environmental impact; on the other hand there can be divergence between different environmental aspects. This makes it difficult to define financial subsidies to promote energy efficiency measures.
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O conhecimento dos riscos e conseqüências da lesão pulmonar induzida pela ventilação mecânica mudou a filosofia da terapia respiratória e tem influenciado nas recomendações e padronizações de seu uso. A influência dos diferentes modos ventilatórios não tem sido estudada em transplante de pulmão. O presente estudo teve como objetivo comparar a influência da ventilação controlada a volume (VCV) com a ventilação controlada a pressão (PCV) no desempenho funcional dos enxertos pulmonares, em modelo canino de transplante pulmonar unilateral utilizando-se doadores após três horas de parada cardiocirculatória. Quinze cães foram randomizados em dois grupos: oito cães foram alocados para o Grupo VCV e sete cães para o Grupo PCV. Cinco cães não completaram o período de avaliação pós-transplante, os dez animais restantes, grupo VCV (n= 5) e grupo PCV (n=5), foram avaliados durante 360 min após o término do transplante pulmonar. O desempenho funcional dos enxertos foi estudado através da avaliação da mecânica respiratória, trocas gasosas e das alterações histopatológicas. Não foram encontradas diferenças significativas em nenhuma das variáveis da mecânica respiratória estudadas (pressões de pico inspiratória- PPI; pressões de platô- PPLAT ; pressões médias de vias aéreas – Pmédia; complacências dinâmica- Cdyn e estática- Cst); da oxigenação, pressão parcial de oxigênio no sangue arterial e venoso misto (PaO2, PvO2); a diferença entre a saturação da hemoglobina no sangue arterial e no sangue venoso misto (ΔSO2); a pressão parcial de dióxido de carbono no sangue arterial e no sangue venoso misto (PaCO2, PvO2). As alterações histopatológicas encontradas nos pulmões dos animais foram compatíveis com o padrão de lesão pulmonar aguda. As alterações histológicas de padrão inespecífico não tiveram nenhuma correlação com o modo ventilatório. Este estudo demonstra que os modos ventilatórios estudados não influenciam as respostas dos enxertos pulmonares à lesão de isquemia reperfusão que se estabelece precocemente neste modelo experimental até 6 horas de reperfusão pulmonar pós-transplante unilateral.
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Stir bar sorptive extraction and liquid desorption followed by large volume injection coupled to gas chromatography–quadrupole mass spectrometry (SBSE–LD/LVI-GC–qMS) had been applied for the determination of volatiles in wines. The methodology was optimised in terms of extraction time and influence of ethanol in the matrix; LD conditions, and instrumental settings. The optimisation was carried out by using 10 standards representative of the main chemical families of wine, i.e. guaiazulene, E,E-farnesol, β-ionone, geranylacetone, ethyl decanoate, β-citronellol, 2-phenylethanol, linalool, hexyl acetate and hexanol. The methodology shows good linearity over the concentration range tested, with correlation coefficients higher than 0.9821, a good reproducibility was attained (8.9–17.8%), and low detection limits were achieved for nine volatile compounds (0.05–9.09 μg L−1), with the exception of 2-phenylethanol due to low recovery by SBSE. The analytical ability of the SBSE–LD/LVI-GC–qMS methodology was tested in real matrices, such as sparkling and table wines using analytical curves prepared by using the 10 standards where each one was applied to quantify the structurally related compounds. This methodology allowed, in a single run, the quantification of 67 wine volatiles at levels lower than their respective olfactory thresholds. The proposed methodology demonstrated to be easy to work-up, reliable, sensitive and with low sample requirement to monitor the volatile fraction of wine.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Background: Obesity impairment to the pulmonary function related to the magnitude of adiposity and is associated with excessive daytime sleepiness (EDS) and snoring, among others symptoms of respiratory disorders related to sleep. It is possible that obese individuals with excessive daytime sleepiness may make changes in lung function on spirometry monitored during the day as a consequence of fragmented sleep or episodes of nocturnal hypoventilation that cause respiratory and changes that can persist throughout the day. The combination of these findings alone sleepiness observed by subjective scales with pulmonary function in obese patients is unknown. Objective: To assess the influence of EDS and snoring on pulmonary function in morbidly obese and distinguish between different anthropometric markers, the snoring and sleepiness which the best predictors of spirometric function and respiratory muscle strength and endurance of these patients. Methods: We evaluated 40 morbidly obese markers on the anthropometric, spirometric respiratory variables, maximal inspiratory and expiratory pressures (MIP and MEP) and maximal voluntary ventilation (MVV) and the measured excessive daytime sleepiness (the Epworth sleepiness scale) and snoring (snoring scale of Stanford). The data were treated when the differences between the groups of obese patients with and without sleepiness, whereas the anthropometric variables, respiratory and snoring. Pearson's correlation was performed, and multiple regression analysis assessed the predictors of pulmonary function. For this we used the software SPSS 15.0 for windows and p <0.05. Results: 39 obese patients were included (28 women), age 36.92+11.97y, body mass index (BMI) 49.3+5.1kg/m², waist-hip ratio (WHR) 0.96+0.07 and neck circumference (NC) 44.1+4.2 cm. Spirometric values and respiratory pressures were up 80% of predicted values, except for endurance (MVV <80%). Obese with EDS have lower tidal volume. Positive correlation was observed between BMI and EDS, EDS and NC and between snoring and BMI, and negative correlation between EDS and tidal volume (TV), and between snoring and snoring FVC and FEV1. In linear regression the best predictor of pulmonary function was snoring, followed by NC. NC has more obese with higher strength (MEP, p = 0.031) and endurance (MVV p = 0.018) respiratory muscle. Conclusion: Obese with EDS tend to have lower TV. In addition, snoring and NC can better predict pulmonary function in obese when compared with other anthropometric markers or EDS. Obese patients with higher NC tend to have greater capacity for overall strength of respiratory muscles, but may have low muscle endurance
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The clinical importance of evaluating the respiratory muscles with a variety of tests has been proposed by several studies, once that the combination of several tests would allow a better diagnosis and therefore, a better clinical follow of disorders of the respiratory muscles. This study aimed to evaluate the feasibility of adapting a national electronic manovacuometer to measure the nasal inspiratory pressure (study 1) and analyze the level of load intensity of maximum voluntary ventilation, as well as the variables that may influence this maneuver in healthy subjects (study 2). We studied 20 healthy subjects by a random evaluation of two measures of SNIP in different equipments: a national and an imported. In study 2 it was analyzed the intensity of the load of MVV test, change in pressure developed during the maneuver, the possible differences between genders, and the correlations between the flow developed in the test and the result of MVV. In study 1 it was found the average for both measures of nasal inspiratory pressures: 125 ± 42.4 cmH2O for the imported equipment and 131.7 ± 28.7 cmH2O for the national one. Pearson analysis showed a significant correlation between the average, with a coefficient r = 0.63. The average values showed no significant differences evaluated by paired t test (p> 0.05). In the Bland-Altman analysis it was found a BIAS = 7 cmH2O, SD 32.9 and a confidence interval of - 57.5 cmH2O up to 71.5 cmH2O. In the second study it was found significant differences between the genders in the air volume moved, being higher in males 150.9 ± 13.1 l / min vs 118.5 ± 15.7 L / min for (p = 0.0002, 95% CI 44.85 to 20:05). Regarding the inspiratory and expiratory loading, they were significantly higher in men than in women, peak inspiratory pressure (34.7 ± 5.3 cmH2O vs 19.5 ± 4.2 cmH2O, 95% CI - 18.0 to -12.3, p <0.0001), peak expiratory (33.8 vs. 23.1 ± 5.9 cmH2O ± 5.4 cmH2O, 95% CI -17.1 to - 4.6, p <0.0001), and the delta pressure (59.7 ± 10 cmH2O vs 36.8 ± 8.3 cmH2O, 95% CI 14.5 to 31.2, p <0.0002). The Pearson correlation showed that the flow generated by the maneuver is strongly correlated with the delta-expiratory pressure / inspiratory (r2= 0.83,R = 0.91, 95%IC 0.72 a 0.97 e p< 0.0001).Through these results we suggest that the national electronic manovacuometer is feasible and safe to perform the sniff test in healthy subjects. For the MVV, there are differences between the genders in the intensity of pressure developed during the maneuver. We found a load intensity considered low during the MVV, and found a strong correlation between the flow generated in the test and the delta pressure expiratory / inspiratory
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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JUSTIFICATIVA E OBJETIVOS: Não existem estudos que associem os efeitos determinados pelas modalidades ventilatórias às repercussões hemodinâmicas durante o pneumoperitônio. O objetivo deste estudo foi avaliar as alterações na hemodinâmica determinadas pelo pneumoperitônio em cães com ventilação por volume e pressão controlados. MÉTODO: Dezesseis cães anestesiados com tiopental sódico e fentanil foram divididos em grupo 1, volume controlado, e grupo 2, pressão controlada, e submetidos ao pneumoperitônio de 10 e 15 mmHg. Foram estudados freqüência cardíaca, pressão arterial média, pressão de átrio direito, pressão de artéria pulmonar ocluída, índice cardíaco, índice de resistência vascular sistêmica e vasopressina plasmática. Os dados foram coletados em 4 momentos. M1 - antes do pneumoperitônio, M2 - 30 minutos após pneumoperitônio com 10 mmHg, M3 - 30 minutos após pneumoperitônio com 15 mmHg, M4 - 30 minutos após a deflação do pneumoperitônio. RESULTADOS: Os resultados mostraram aumento no índice cardíaco, nas pressões de átrio direito e de artéria pulmonar ocluída em M2 e M3, em ambos os grupos. A vasopressina não variou durante o procedimento e o índice de resistência vascular sistêmica não aumentou, proporcionando estabilidade da pressão arterial média em ambos os grupos. CONCLUSÕES: As modalidades ventilatórias não determinaram diferenças na resposta hemodinâmica entre os grupos estudados. A técnica anestésica utilizada e as pressões intra-abdominais alcançadas determinaram estabilidade da pressão arterial média, provavelmente decorrente da ausência do aumento no índice da resistência vascular sistêmica.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)