Oxygen Consumption Data Research Articles

Variações na demanda de energia metabólica de juvenis deHaemulon steindachneri (Perciformes, Haemulidae) em função da temperatura

Bioenergetic aspects of juvenile Haemulon steindachneri collected at Ubatuba (23°30'S), SP, Brazil, were evaluated as function of body weight and temperature (15°C, 20°C e 26°C) through the oxygen consumption and ammonia excretion analyses. Q10 values and elevations a of the regression of oxygen consumption on wet weight at 15°C and 20°C were not significantly different. On the other hand, Q10 and elevations a were significantly different between 20°C and 26°C. It is suggested that 15-20°C is a temperature range of thermal metabolic independence for H. steindachneri, and this might be related to physiological adaptation to the environmental constraints. Daily energetic costs of routine metabolism were calculated from oxygen consumption data and other parameters of the bioenergetic equation were estimated following a model proposed in the literature. For a fish of 20g and 70g body weight (the minimum and maximum common weights at the 3 tested temperatures), it was estimated that their daily energetic demand at 15°C were 868.83 cal/day and 3168.65 cal/day; at 20°C are 893.22 cal/day and 2654.04 cal/day and at 26°C were 1390.30 cal/day and 5046.61 cal/day. Results contribute to the understanding of the ecological role of the species and its adaptation to the environment.

Oxygen Uptake Kinetics and Functional Status Issues in Congestive Heart Failure: A Pilot Report

Collection of peak oxygen consumption (V02) data provides valuable information with respect to prognosis and activity guidelines in the congestive heart failure (CHF) population. This pilot study examines the relationship between Duke Activity Status Index (DASI) score, calculated peak oxygen consumption (V02), and measured peak VO2. Six subjects, 3 males and 3 females, with stable CHF completed the DASI and underwent a symptom-limited ramp treadmill test. A metabolic cart was used to measure VO2 during testing. Mean measured VO2, calculated V02, and DASI score were 11.49 ± 3.86 m1O2/kg/min-1, 19.48 (6.24 mlO2/kg/min-1, and 20.09 ± 3.38 mlO2/kg/min-1 respectively. A Friedman two-way analysis of variance by ranks found no significant difference between DASI score and calculated VO2. However, a significant difference did exist between measured V02 and DASI scores as well as measured V02 and calculated V02 (p < 0.0085). These preliminary findings suggest that subjects with stable CHF can attain a calculated aerobic intensity level in excess of their measured V02. Interestingly, their perceived functional capacity is more closely related to calculated rather than measured V02. If confirmed by expansion of the subject pool, these findings have implications for future research endeavors, and clinicians interpreting V02 data for exercise and physical activity counseling in CHF patients.

Biodegradation of polyester-amides using a pure strain of micro-organisms or papainI. Model compounds

Various amides and model compounds derived from phenylalanine and succinic acid have been degraded in abiotic and biotic conditions as a first step in the study of the mechanism, rate and extend of mineralization of polyesteramides. These compounds have been incubated in the presence of pure strains of micro-organisms isolated from an industrial compost for household refuse. The rate of substrate disappearance has been measured by UV absorption spectroscopy or determined from oxygen consumption data as a function of time. Attention has been paid to the configuration of the amino-acid and to the nature of the terminal groups. It has been shown that the decay of such compounds is due to the presence of amino-acid and not to the nature of the end groups. N-Succinyl- l-phenylalanine HOOC-CH(CH 2-Ph)-NH-CO-(CH 2) 2-COOH has been demonstrated to be very rapidly mineralized while the corresponding dimeric compound N, N′-Succinyl- l, l-phenylalanine HOOC-CH(CH 2-Ph)-NH-CO-(CH 2) 2-CO-NH-CH(CH 2-Ph)-COOH was much more slowly degraded, most probably because of its larger size. The difference between the biodegradation processes mediated by micro-organisms and by isolated enzymes is emphasized.

Maintenance energy demand and starvation recovery dynamics of Nitrosomonas europaea and Nitrobacter winogradskyi cultivated in a retentostat with complete biomass retention.

Nitrosomonas europaea and Nitrobacter winogradskyi (strain "Engel") were grown in ammonia-limited and nitrite-limited conditions, respectively, in a retentostat with complete biomass retention at 25 degrees C and pH 8. Fitting the retentostat biomass and oxygen consumption data of N. europaea and N. winogradskyi to the linear equation for substrate utilization resulted in up to eight-times-lower maintenance requirements compared to the maintenance energy demand (m) calculated from chemostat experiments. Independent of the growth rate at different stages of such a retention culture, the maximum specific oxygen consumption rate measured by mass spectrometric analysis of inlet and outlet gas oxygen content always amounted to approximately 45 micromol of O2 mg-1 of biomass-C x h-1 for both N. europaea and N. winogradskyi. When bacteria were starved for different time periods (up to 3 months), the spontaneous respiratory activity after an ammonia or nitrite pulse decreased with increasing duration of the previous starvation time period, but the observed decrease was many times faster for N. winogradskyi than for N. europaea. Likewise, the velocity of resuscitation decreased with extended time periods of starvation. The increase in oxygen consumption rates during resuscitation referred to the reviving population only, since in parallel no significant increase in the cell concentrations was detectable. N. europaea more readily recovers from starvation than N. winogradskyi, explaining the occasionally observed nitrite accumulation in the environment after ammonia becomes available. From chloramphenicol (100 microg x ml-1) inhibition experiments with N. winogradskyi, it has been concluded that energy-starved cells must have a lower protein turnover rate than nonstarved cells. As pointed out by Stein and Arp (L. Y. Stein and D. J. Arp, Appl. Environ. Microbiol. 64:1514-1521, 1998), nitrifying bacteria in soil have to cope with extremely low nutrient concentrations. Therefore, a chemostat is probably not a suitable tool for studying their physiological properties during a long-lasting nutrient shortage. In comparison with chemostats, retentostats offer a more realistic approach with respect to substrate provision and availability.

Physiological Demands of Concrete Slab Placing and Finishing Work

Construction craft work is physically demanding. As a result, many craft workers become excessively fatigued, which may lead to decreased productivity and motivation, inattentiveness, poor judgment, poor quality work, job dissatisfaction, accidents, and injuries. This paper investigates the feasibility of measuring \Iin situ\N physical demands of concrete slab placing and finishing work and how this physical demand may be used to characterize both work intensity and whether the demands are physically fatiguing to the workers. Physiological measures of energy expenditure, including oxygen consumption and heart rate data, were collected for an eight-member concrete slab placing and finishing crew performing actual construction work. The results reveal that most of the crew members who were performing manual work experienced heavy physical demands and more potential for physical fatigue compared with those operating construction machinery and equipment. These workers routinely exceed one or more published guidelines for acceptable levels of energy expenditure, oxygen consumption, and heart rate. The methods described in this paper have wide application in identifying excessively demanding construction tasks so the work can be modified and productivity improved.

A Neuromuscular and Metabolic Comparison between Forward and Reverse Pedaling

The purpose of this study was to determine how muscle activity and oxygen consumption are influenced by reverse pedaling (RP) compared to forward pedaling (FP). Seventeen physically active males performed FP and RP at an external workrate of 157 W (80 rpm) while EMG data were collected from five muscles: rectus femoris (RF), biceps femoris (BF), gastrocnemius (GN), tibialis anterior (TA), and vastus medialis (VM). Oxygen consumption (V̇O2 L·min-1) data were collected. On-time durations and EMG amplitudes were quantified for each half-cycle (first 180° and second 180° of crank angle). V̇O2 was similar between pedaling conditions while muscles RF and BF exhibited phasic shifts in response to RP with no amplitude change. VM showed an increase and GN displayed a decrease in EMG amplitude from FP to RP. The phasic shifts in muscle activation seen in RP, particularly in RF and BF, may alter the sequence of the knee extensor–hip extensor joint moments during the first half-cycle of pedaling.

Field validation of an energy expenditure model for walking soldiers

This paper discusses the collection of field data used to provide some validation of a model of energy expenditure for walking soldiers. The simulation of physical performance can be used to predict soldier performance in a synthetic environment such as a battle simulation. Soldier energy expenditure is a useful model because it forms the basis for other predictive models such as body core temperature and sweating rate. Data was collected from a number of soldiers performing various activities over a range of terrains. Walking speed and gradient data was collected by storing position information obtained from a Global Positioning System (GPS) receiver. Samples of expired air were taken to estimate oxygen uptake. Soldier weight, carried load and heart rate were also recorded. The validation of an energy expenditure model coded into the CAEN battle simulation by use of GPS data, heart rate data and oxygen consumption data collected in a field environment appears usable. The results indicate the significance of an upward slope on energy expenditure. Even though only small gradients were experienced in this study, they caused large increases in energy expenditure. The assumption made in the study that negative slopes could be approximated to level terrain was not supported. Relevance to the industry To ensure accurate simulation of a human energy expenditure model that can be used for predictive purposes, field validation studies must be made. This paper documents some techniques used for that field validation.

Treadmill Exercise Testing in an Epidemiologic Study of Elderly Subjects

We sought to characterize the physical performance of older subjects in a community-based study of aging and fitness and to establish norms of oxygen consumption during exercise in this group. A community-based census identified 3057 age-eligible individuals of whom 2092 individuals (68.4%) agreed to participate in the overall study. Of these, 1101 subjects between 55 and 94 years of age who were free of known heart disease and able to perform treadmill exercise were tested using the Cornell protocol. Of these 1101 subjects, 73.8% of women and 89.5% of men (p < .001) exceeded what was considered a minimal threshold workload [i.e., > or =2 min of exercise and a respiratory exchange ratio (RER) > or = 1.00]. Moreover, 32.9% of women and 52.7% of men achieved a RER > or = 1.10 and were considered to have achieved maximal exercise. For all subjects who exceeded the minimal exercise workload, the mean exercise duration was 10.0 +/- 4.0 min for women and 13.2 +/- 4.6 min for men. Peak VO2/kg x min(-1) decreased linearly with age for both women (y = 38.33 - 0.27 x age + 1.12 H) and men (y = 41.78 - 0.26 x age + 12.65 H - 0.15 H x age), (p < .001 for sex difference), where H is defined as presence (=1) or absence (=0) of a disease condition. However, this sex-related difference disappeared when VO2/kg x min(-1) was adjusted for lean body mass. Thus, from a community-based sample of older persons, we have provided data (by 5-year age groups) for rates of participation in treadmill exercise testing and the success rate for achieving maximal exercise. Oxygen consumption and other exercise data are presented for older, healthy subjects as well as for those with various chronic diseases associated with aging (excluding those with cardiac or cerebrovascular disease). Exercise duration, peak VO2/kg x min(-1) (normalized for total and lean body mass), and peak exercise heart rate declined with age. Most of the sex difference in peak VO2/kg x min(-1) could be explained by the greater percent of body fat in women.

Growth, consumption, and productivity of the California killifish in Ojo de Liebre Lagoon, Mexico

The growth curve of the California killifish Fundulus parvipinnis was estimated from length–frequency data using FiSAT software. The population structure was calculated and was extrapolated over the total area of the lagoon to estimate the total biomass. Using published data of oxygen consumption and ancillary data, the consumption of food by killifish was also estimated. Production of the species was via the first derivative of the von BertalanVy growth curve. This approach is proposed for other species whose biology is described in the literature.

Growth, consumption, and productivity of the California killifish in Ojo de Liebre Lagoon, Mexico*1

The growth curve of the California killifish Fundulus parvipinnis was estimated from length–frequency data using FiSAT software. The population structure was calculated and was extrapolated over the total area of the lagoon to estimate the total biomass. Using published data of oxygen consumption and ancillary data, the consumption of food by killifish was also estimated. Production of the species was via the first derivative of the von BertalanVy growth curve. This approach is proposed for other species whose biology is described in the literature.

Fire Behaviour of Unsaturated Polyesters

This work is concerned with the fire behaviour of unsaturated polyester resins and particularly with the limiting oxygen index and oxygen consumption data. The influence of styrene level on the rate of heat release is shown. The combustion products of the resins are identified. No change in the nature or proportions of the evolved gases could be detected with different amounts of styrene.

Fire Behaviour of Unsaturated Polyesters

This work is concerned with the fire behaviour of unsaturated polyester resins and particularly with the limiting oxygen index and oxygen consumption data. The influence of styrene level on the rate of heat release is shown. The combustion products of the resins are identified. No change in the nature or proportions of the evolved gases could be detected with different amounts of styrene.

Field-scale investigations on the biodegradation of chlorinated aromatic compounds and HCH in the subsurface environment

The biological in situ remediation of a former pesticide production site, highly contaminated with chlorobenzenes, chlorophenols and hexachlorocyclohexanes, was studied for a period of one year. Field experiments testing the remediation technology were carried out in the subsurface to a depth of 5.5 m. Detailed monitoring of several chemical and microbiological parameters was made in order to evaluate the remediation success. The initial pollution of this site ranged from 0.03–0.30 g EOX (extractable halogenated organic compounds)/kg soil in the saturated layer to 1–20 g kg −1 EOX in the unsaturated layer, whereas the impounded water was polluted with 8–13 mg L −1 AOX (adsorbable halogenated organic compounds). No significant decrease of the pollutants in the subsoil was observed, although oxygen and nutrients were supplied in sufficient concentrations. In contrast, several of the chlorinated organic compounds were eliminated from the water treatment plant, either by physical or biological processes. Based on measurements of AOX in different parts of the plant, 26% of the pollutants was found adsorbed on the activated carbon and 3% was found in the sludge of the filter back-wash. Dependent on these measurements, elimination of ∼ 70% of the pollutants was attributed to microbial degradation. The latter fact is supported by oxygen consumption data, by increase in the microbial counts and by changes in the distribution of the pollutants in the plant effluent. Among the chlorobenzenes, 1,2,4-trichlorobenzene, and among the hexachlorocyclohexanes, a-hexachlorocyclohexane were eliminated preferentially. The results suggest that an in situ remediation of a site polluted with chlorinated organic compounds cannot be recommended; however, an on site circulation water treatment is possible by a combination of physical and biological processes.

Estudo do metabolismo de rotina e excreção de amônia do antípoda antártico Waldeclàa obesa em duas temperaturas distintas

Realizaram-se estimativas, a 0ºC e a 3ºC, do consumo médio e específico de oxigênio e da excreção média e específica de amónia de anfípodas antárticos da espécie Waldeckia obesa, coletados na Baía do Almirantado, Ilha Rei George, Antártica. Os experimentos foram realizados na Estação Antártica Brasileira "Comandante Ferraz" e no Laboratório de Ecologia Polar do Instituto Oceanográfico da Universidade de São Paulo. Foram empregados animais entre 120 mg a 620 mg e entre 40 mg e 690 mg de peso úmido, nos experimentos a 0ºC e a 3ºC, respectivamente. Dentro dessas faixas de peso, o consumo médio de oxigênio, a 0ºC, variou de 2,22µl/h a 10,81µl/h e o específico de 0,011µl/mg/h a 0,018µl/mg/h. A 3ºC, o consumo médio de oxigênio variou de 1,83µl/h a 14,19µl/h e o específico de 0,033µl/mg/h a 0,022µl/mg/h. O Q10, calculado a partir das médias das classes, foi de 6,95. Por sua vez, a excreção média de amónia, a 0ºC, variou de 13,84 ng.at/h a 55,34 ng.at/h e a específica entre 0,090 ng.at/mg/h a 0,042 ng.at/mg/h. A 3ºC, a excreção média de amónia variou de 5,11 ng.at/h a 38,33 ng.at/h e a específica de 0,088 ng.at/mg/h a 0,059 ng.at/mg/h. A relação 0:N indica que uma mistura de proteínas e lipídios é utilizada como substrato para o catabolismo. A 3ºC, entretanto, há uma tendência a aumentar a contribuição dos lipídios nesse substrato. O consumo de oxigênio de Waldeckia obesa é bastante baixo estando de acordo com os valores encontrados, a 0ºC, por outros autores. Esses dados, juntamente com resultados recentes encontrados na literatura, indicam a fragilidade da hipótese de "adaptação metabólica ao frio", que supõe terem os animais marinhos ectotérmicos antárticos taxas metabólicas elevadas, como resposta adaptativa às baixas temperaturas. Os dados de consumo de oxigênio e excreção de amónia fornecem material básico para extrapolação a parâmetros populacionais, fornecendo subsídios para a avaliação do papel ecológico desses animais no ecossistema em que vivem.

Effect of instrument response time on heat release rate measurements

AbstractA linear hereditary integral technique provides simple analytic solutions for deconvoluting thermopile and oxygen consumption data to remove the effect of instrument response time on peak and integrated heat release rate values. A comparison of corrected and uncorrected thermopile and oxygen sensor data obtained on an Ohio State University (OSU) apparatus for various materials indicates that significant errors in peak and integrated heat release rate can result from delayed instrument response to repidly changing heat flows. However, correcting for temporal effects alone using this procedure does not account for differences between heat release rate values obtained by thermopile and oxygen consumption methods.

Direct calorimetry of aquatic animals: Automated and computerized data-acquisition system for simultaneous direct and indirect calorimetry

A system for computerized registration of heat production data and oxygen tension values of a differential 1 litre flow-through microcalorimeter (Setaram GF 108) is described. The linked values of oxygen concentration and heat production data were simultaneously stored on a computer. The aerobic and total heat production rates were thus measured of goldfish ( Carassius auratus L.) during normoxia, hypoxia and anoxia exposure. Incidentally, a partial anaerobic response was observed in goldfish during normoxia. During severe hypoxia and anoxia, goldfish respond with a reduction of the metabolic rate and a strong increase of anaerobic heat production. From the linked oxygen consumption and heat production data, the oxycaloric equivalent was calculated. The described system enables us to study continuously the effects of environmental factors on the metabolic rate of aquatic organisms.

Comparison of the formation of malondialdehyde and thiobarbituric acid-reactive substances from autoxidized fatty acids based on oxygen consumption

Fatty acid having 18 carbon atoms was oxidized at 170 degrees C in a closed vessel to measure the oxygen consumption, which was assumed to be a chemically reliable index for the autoxidation. The yields of malondialdehyde (MDA) and 2-thiobarbituric acid-reactive substances (TBA-RS) were compared with the data for oxygen consumption. In autoxidation of oleic acid, the formation of MDA and TBA-RS correlated with the consumed oxygen up to the value of 700 micromoles/L. When the oxygen consumption exceeded the value, MDA did not increase and TBA-RS tended to decrease. In autoxidation of linoleic acid, TBA-RS linearly increased with the oxygen consumption up to 2000 micromoles/L. MDA also increased with oxygen consumption up to 700 micromoles/L but thereafter reached a plateau. The yield of MDA from linoleic acid was similar to that from oleic acid. In autoxidation of linolenic acid, the formation of MDA and TBA-RS correlated with the oxygen consumption until the value reached 1150 micromoles/L. When the oxygen consumption exceeded that value, MDA and TBA-RS decreased. Neither MDA nor TBA-RS was detected from stearic acid in spite of the increase in oxygen consumption up to 2200 micromoles/L.

The use of combined antegrade-retrograde infusion of blood cardioplegic solution in pediatric patients undergoing heart operations

The benefits of combined antegrade-retrograde infusion of blood cardioplegic solution are becoming well known in adult coronary and valvular heart operations. Many of these advantages relate directly to the pediatric patient. They include prompt arrest and even distribution, particularly with aortic insufficiency or open aortic root, avoiding or limiting ostial cannulation, allowing uninterrupted surgical procedures, and flushing air/debris from the coronary arteries. We therefore report on the first 123 pediatric patients at the University of California, Los Angeles, to receive myocardial protection with antegrade (aortic) infusion in conjunction with retrograde (coronary sinus) infusion of blood cardioplegic solution. We employed a retroplegia catheter with a self-inflating and deflating occlusion balloon on the tip of a pressure-monitored infusion cannula that remains in the coronary sinus during the operation. Induction blood cardioplegic solution, 30 ml/kg in equally divided doses, is administered in the coronary sinus first antegrade at an aortic pressure less than 80 mm Hg, followed by retrograde infusion at less than 40 mm Hg. Maintenance cardioplegic solution (15 ml/kg) is administered every 20 minutes through one or both of the infusion cannulas, depending on the surgical procedure. Patients' ages ranged from 1 week to 16 years with a mean of 4.6 years. The following procedures were included in descending order: Fontan 20, atrioventricular valve repair/replacement (and complete atrioventricular canal) 16, aortic root/Konno/Ross 16, Rastelli 13, aortic valve repair/replacement 13, ventricular septal defect (and double-outlet right ventricle) 13, tetralogy of Fallot 10, coronary artery reimplantation/fistula repair 6, truncus arteriosus 4, arterial switch 3, bidirectional Glenn 2, sinus venosus 2, and aortopulmonary window, Senning, Stansel, interrupted aortic arch, and Ebstein's, 1 each. Aortic crossclamp times ranged from 6 to 219 minutes with a mean of 87 minutes. Myocardial oxygen consumption data for a series of six patients indicated the supplemental benefit for retrograde infusion of cardioplegic solution along with antegrade infusion, particularly in hypertrophied myocardium. Three deaths occurred (2.4% 30-day mortality), in the following patients: the first with truncus arteriosus and interrupted aortic arch, the second with complete atrioventricular canal and pulmonary hypertension, and the third with truncal valve regurgitation and replacement. There were no complications related to the retroplegia catheter. From this initial positive experience, we conclude that (1) combined antegrade-retrograde infusion of blood cardioplegic solution can be safely used in an expanding number of pediatric heart operations in all age groups, and (2) combined antegrade-retrograde infusion of blood cardioplegic solution may provide additional myocardial protection, with excellent surgical outcome, in complex congenital heart repairs.

The relationship between water velocity, energetic costs, and microhabitat use in four North American stream fishes

We employed field and laboratory data to test the hypothesis that microhabitat use by rainbow trout (Oncorhynchus mykiss), rosyside dace (Clinostomus funduloides), longnose dace (Rhinichthys cataractae) and mottled sculpin (Cottus bairdi) was affected by energetic constraints. Both rainbow trout and rosyside dace occupied water-column microhabitats in Coweeta Creek, North Carolina, U.S.A. These species were over-represented at velocities requiring lower rates of oxygen consumption, as predicted by an energetic cost hypothesis. Morphological and behavioral adaptations of the two benthic species (mottled sculpin and longnose dace) enabled them to hold position over a wide range of velocities without significant changes in oxygen consumption. Focal point velocities of longnose dace were not significantly different from those available, suggesting a lack of velocity preference. Mottled sculpin, however, consistently were over-represented at low velocities, even though oxygen consumption data showed that energetic costs were not decreased by occupying these microhabitats. Our results indicate that microhabitat use by rainbow trout and rosyside dace is consistent with predictions of an energetic cost hypothesis, whereas the morphological adaptations of longnose dace and mottled sculpin minimize the constraints of energetic costs in microhabitat selection.

Energetic Cost of Suspension Feeding versus Particulate Feeding by Juvenile Sacramento Blackfish

All species of suspension-feeding teleost fishes switch from particulate feeding to suspension feeding at a standard length of about 2–5 cm. Although this ontogenetic shift in feeding mode is suggestive of an energetic or biophysical constraint that restricts small fishes to particulate feeding, there have been no comparisons of the energetic costs of pump suspension feeding and particulate feeding based on oxygen consumption data. We found that the O2 consumption (mg O2/[g body weights·h]) associated with the capture of prey by juvenile Sacramento blackfish Orthodon microlepidotus (Cyprinidae) during pump suspension feeding on small zooplankton did not differ significantly (P > 0.05) from that measured during particulate feeding on large zooplankton. The metabolic cost of energy acquisition (mg O2/[g body weights·103 J prey consumed]) was approximately 2.5 times higher (P ≤ 0.02) for pump suspension feeding than for particulate feeding. However, because the actual energy expenditure during the feeding period was only about 2% of the energetic content of the Artemia nauplii consumed during suspension feeding and less than 1% of the energetic content of the Artemia adults consumed during particulate feeding, the advantage of particulate feeding may be a potentially high rate of energy intake rather than a low energy expenditure. Because suspension feeding provides a lower rate of energy intake, small fishes may be unable to obtain the energy required for growth and maintenance by this feeding mode.