ABSTRACT Ischemia is responsible for many metabolic abnormalities in the heart, causing changes in organ function. One of modifications occurring in the ischemic cell is changing from aerobic to anaerobic metabolism. This change causes the predominance of the use of carbohydrates as an energy substrate instead of lipids. In this case, the glycogen is essential to the maintenance of heart energy intake, being an important reserve to resist the stress caused by hypoxia, using glycolysis and lactic acid fermentation. In order to study the glucose anaerobic pathways utilization and understand the metabolic adaptations, New Zealand white rabbits were subjected to ischemia caused by Inflow occlusion technique. The animals were monitored during surgery by pH and lactate levels. Transcription analysis of the pyruvate kinase, lactate dehydrogenase and phosphoenolpyruvate carboxykinase enzymes were performed by qRT-PCR, and glycogen quantification was determined enzymatically. Pyruvate kinase transcription increased during ischemia, followed by glycogen consumption content. The gluconeogenesis increased in control and ischemia moments, suggesting a relationship between gluconeogenesis and glycogen metabolism. This result shows the significant contribution of these substrates in the organ energy supply and demonstrates the capacity of the heart to adapt the metabolism after this injury, sustaining the homeostasis during short-term myocardial ischemia.

Este trabalho foi desenvolvido com o objetivo de determinar, em condições laboratoriais, o coeficiente de descarga (Cd) dos emissores fixos tipo “spray” (Senninger, Nelson e Fabrimar) utilizados em equipamentos pivô central no Brasil. Foram avaliados 45 bocais Senninger, 42 bocais Nelson e 36 bocais Fabrimar, com três repetições, totalizando 369 bocais ensaiados. As pressões de funcionamento variaram entre 6 e 30 PSI (41,37 a 206,84 kPa), com intervalo de leitura a cada 2 PSI (13,79 kPa), totalizando 13 pressões analisadas por bocal. Foram ajustadas as curvas do coeficiente de descarga em função do diâmetro de bocal, para quatro pressões de operação: 10; 15; 20 e 30 PSI (68,95; 103,42; 137,90 e 206,84 kPa). Utilizou-se de dois manômetros de precisão (analógico e digital) previamente calibrados em um manômetro de peso morto. As vazões foram obtidas utilizando três medidores eletromagnético-indutivos, calibrados em recipiente volumétrico. O diâmetro dos bocais foi mensurado através de uma ampliação em projetor de perfil da marca Starrett, modelo HB 400. Os resultados evidenciaram que o coeficiente de descarga varia em função da pressão e do diâmetro do bocal. Nos ensaios conduzidos, obtiveram-se Cds compreendidos na faixa de 0,88 a 0,98 para a faixa de emissores analisados.

This study aimed to determine the discharge coefficients (Cd) of sprinkler fixed-nozzles (Senninger, Nelson and Fabrimar), used in Brazilian center-pivot equipment, under laboratory conditions. These tests used the pressure range standard existing in the nozzle market (psi). A set of 45 Senninger, 42 Nelson and 36 Fabrimar nozzles were assessed, with three replications, in a total of 369 tested nozzles. Operating pressures ranged from 6 to 30 psi (41.37 to 206.84 kPa), with a reading gap of 2 psi (13.79 kPa), totaling 13 measures for nozzle. Discharge coefficient curves were drawn as function of nozzle size and operating pressures, which were 10, 15, 20, and 30 psi (68.95, 103.42, 137.90 and 206.84 kPa). Two precision pressure gauges (one analog and one digital) were used; being calibrated against a dead weight gauge. Flow rates were obtained using three electromagnetic induction gauges calibrated with volumetric data. Nozzle diameters were measured using a profile projector Model HB 400 (Starrett, São Paulo, Brazil). The results evidenced that discharge coefficient varies with nozzle diameter and operating pressure. Tests showed Cds within the range of 0.88 to 0.98, for the assessed nozzles.