Biosorption of uranium(VI) from aqueous solution by biomass of brown algae Laminaria japonica

The uranium(VI) adsorption efficiency of non-living biomass of brown algae was evaluated in various adsorption experimental conditions. Several different sizes of biomass were prepared using pretreatment and surface-modification steps. The kinetics of uranium uptake were mainly dependent on the particle size of the prepared Laminaria japonica biosorbent. The optimal particle size, contact time, and injection amount for the stable operation of the wastewater treatment process were determined. Spectroscopic analyses showed that uranium was adsorbed in the porous inside structure of the biosorbent. The ionic diffusivity in the biomass was the dominant rate-limiting factor; therefore, the adsorption rate was significantly increased with decrease of particle size. From the results of comparative experiments using the biosorbents and other chemical adsorbents/precipitants, such as activated carbons, zeolites, and limes, it was demonstrated that the brown algae biosorbent could replace the conventional chemicals for uranium removal. As a post-treatment for the final solid waste reduction, the ignition treatment could significantly reduce the weight of waste biosorbents. In conclusion, the brown algae biosorbent is shown to be a favorable adsorbent for uranium(VI) removal from radioactive wastewater.

A comprehensive study on the laser decontamination of surfaces contaminated with Cs(+) ion

A Q-switched Nd:YAG laser with a 1064nm, 450mJ/pulse and 14ns pulse width was employed to study the decontamination characteristics of Type 304 stainless steel specimens contaminated with Cs(+) ions. The surrogate specimens were artificially contaminated with two kinds of premixed solutions. The laser was irradiated for 10, 20 and 100 shots. The results were investigated using a SEM, EPMA and XPS. For the surrogate specimen treated with the CsCl+KCl solution, more than 98% of the Cs(+) ions were removed during an irradiation of 100 shots. The specimen treated with the CsCl+KCl solution was easier to decontaminate. By comparing the ratio of the O(1s) intensity to the Fe(2p) intensity of the XPS spectra, it was found that the oxygen atoms that had evolved from the specimen treated with the CsNO(3)+KNO(3) solution had decreased the laser's decontamination performance.

Risk assessment of human exposure to cypermethrin during treatment of mandarin fields

The potential dermal and respiratory exposure assessment and risk assessment for applicator were performed with cypermethrin EC. The pesticide was applied on a mandarin field using a power sprayer. Gloves were used for the hand exposure assessment, mask for face, and dermal patches for the other parts of the body. Personal air monitor equipped with a XAD-2 resin was used for the respiratory exposure assessment. During the application of cypermethrin in the field, the rate of potential dermal exposure ranged from 28.1 to 58.8 mg/h. The major exposure parts were upper-arms (22.1-24.6%) and legs (thigh and shin, 28.3-29.2%) for females and thigh (21.0-46.9%) and hand (14.9-19.3%) for males. Females were exposed more than males. No exposure was detected from the respiratory monitoring. For risk assessment, the potential dermal exposure (PDE), the absorbable quantity of exposure (AQE), and the margin of safety (MOS) were calculated. Among those four risk assessments, MOS was < 1 in only trial I, which indicated any possibility of risk. However, in the others, the possibility of risk was little. Moreover, the safe work time ranged from 3.61 h to 9.69 h.

In vivo pharmacokinetics of pyribenzoxim in rats

Pyribenzoxim, benzophenone O-[2,6-bis(4,6-dimethoxypyrimidin-2-yloxy)benzoyl]oxime, is a new post-emergence herbicide providing broad-spectrum weed control in rice fields. [14C]Pyribenzoxim was used to study the pharmacokinetics of the compound after oral administration of a dose of 1000 mg kg-1 to male Sprague-Dawley rats. The material balance ranged from 97.3 to 99.7% of the administered dose and urinary and fecal recovery accounted for 97.1%, with the majority of radioactivity recovered in feces (88.6%) by 168 h after treatment. Elimination as volatile products or as carbon dioxide was negligible. The following values were obtained for the compound in the blood: AUC0-168 h, 28,400 micrograms equiv hg-1; Tmax, 12 h; Cmax, 372 micrograms equiv g-1; half-life, 53 h. Radioactivity in tissue decreased from 96.1% of applied radiocarbon at 6 h to 0.4% at 168 h and the highest concentration of radioactivity among the tissues was observed in liver while the lowest residues were found in brain. The elimination half-lives of radioactivity from tissues was in the range of 7 to 77 h and Tmax values of 12, 24 and 12 h were observed for blood, liver and kidney, respectively. Except for that in the digestive tract, the tissue-to-blood ratio (TBR) was highest in the liver.

Delayed platelet dysfunction in prolonged induced canine hypothermia

Mild to moderate hypothermia (33-32 degrees C) is recognized as beneficial for brain protection after brain trauma. However, there are few experimental reports on hemostatic changes during prolonged hypothermia. We compared hemostatic changes during 72 h of mild to moderate hypothermia with data in normothermic dogs.

METHOD

Mongolian dogs in a hypothermic group (N=7, 33 degrees C core temperature) and normothermic group (N=6, 37.5 degrees C core temperature) were anesthetized and instrumented to control temperatures and record hemodynamic changes continuously. Hypothermia or normothermia was maintained for 72 h. Platelet count, platelet aggregation, and thromboelastograms (TEG) were measured in each group.

RESULTS

Heart rate, blood pressure, pulmonary pressure and blood gas were not significantly different between the two groups. Platelet counts, compared to baseline values, were significantly decreased in both groups (P<0.01). Platelet aggregation was significantly decreased in the hypothermic group after 24 h (P<0.04).

CONCLUSION

Long-term hypothermia induced platelet dysfunction, leading to decreased platelet aggregation and prolonged coagulation time (R and K times of TEG).

Long-term mild hypothermia with extracorporeal lung and heart assist improves survival from prolonged cardiac arrest in dogs

BACKGROUND AND PURPOSE

although normothermic extracorporeal lung and heart assist (ECLHA) improves cardiac outcomes, patients can not benefit from hypothermia-mediated brain protection. The present study evaluated the effects of long-term ECLHA with mild to moderate hypothermia (33 degrees C) in a canine model of prolonged cardiac arrest.

METHODS

15 dogs were assigned to either the hypothermic (seven dogs, 33 degrees C) or normothermic group (eight dogs, 37.5 degrees C). All dogs were induced to normothermic ventricular fibrillation (VF) for 15 min, followed by 24 h of ECLHA and 72 h of intensive care. The hypothermia group maintained core (pulmonary artery) temperature at 33 degrees C for 20 h starting from resuscitation, then were rewarmed by 28 h. Outcome evaluations included: (1) mortality; (2) catecholamine dose; (3) time to extubation; (4) necrotic myocardial mass (g); and (5) neurological deficits score (NDS).

RESULTS

in the normothermic group five dogs died of cardiogenic shock and one dog succumbed to poor oxygenation. The two surviving dogs remained comatose (NDS 60.5 +/- 4.9%) with necrotic myocardial mass of 14.5 +/- 3.5 g. In the hypothermic group, one dog died from pulmonary dysfunction, the other six dogs survived. The surviving dogs showed brain damage (29.8 +/- 2.5%), but there was evidence of some brain-protective effect. The mass of necrotic myocardium was 4.2 +/- 1.3 g in the hypothermic group or 3.4 times smaller than in the normothermic group. The survival rate was significantly higher in the hypothermic than in the normothermic group (P < 0.05). The catecholamine requirement was also lower in the hypothermic than in the normothermic dogs (P < 0.05).

CONCLUSIONS

Long-term mild to moderate hypothermia with ECLHA induced immediately after cardiac arrest improved survival as well as cerebral and cardiac outcomes.

Heparin bonding of the extracorporeal circuit reduces thrombosis during prolonged lung assist in goats

This study investigated whether an artificial membrane lung of nonmicroporous polyolefin hollow fibers bonded with heparin could prolong venoarterial extracorporeal lung assist (ECLA) with low dose systemic heparin in goats. We compared heparin bonded circuits (Carmeda Bioactive Surface, "HB" group, n = 5) with non heparin bonded circuits ("NHB" group, n = 5) in venoarterial ECLA (V-A ECLA) for 7 days. Activated coagulation time (ACT) was maintained at approximately 130 sec by systemic infusion of small doses of heparin in the HB group, and at 200-230 sec in the NHB group. Thrombus formation was assessed by visual examination of the circuit, and possible cerebral embolization of thrombi was observed from behavioral abnormalities of the animals. The mean heparin dose given during ECLA was 20.4 +/- 3.6 U/kg per hr in HB, and 50.9 +/- 14.2 U/kg per hr in NHB, significantly less in HB than NHB (p < 0.01). Blood gas changes across the oxygenator, bypass flow rate, platelet aggregation activity, platelet counts, fibrin monomer (FM) test, and antithrombin-III (AT-III) activity did not differ between the two groups. In HB, thrombi were fewer and no abnormal neurologic symptoms were observed during ECLA. Numerous thrombi were observed in all oxygenators with NHB. One NHB goat developed convulsions and cerebral hemorrhage on the 6th day of ECLA. Nonmicroporous polyolefin hollow fibers can be bonded with heparin. An artificial membrane lung constructed of these fibers showed good anticoagulation by decreased thrombus formation with a small dose of infused heparin.

Jugular vein temperature reflects brain temperature during hypothermia

PURPOSE

The neuroprotective properties of mild to moderate hypothermia are well recognized but may not be employed correctly because brain temperature cannot usually be measured directly. This study investigated the jugular vein as a more accessible site that accurately reflects the actual brain temperature during mild, induced hypothermia.

METHODS

We selected ten mongrel dogs (mean weight 12 +/- 2 kg) and measured temperatures of the brain, jugular vein, cisterna magna, pulmonary artery and rectum during hypothermia, including cooling and rewarming. The brain temperature needle probe was inserted 2.0 cm into the parenchyma. A temperature probe was placed in the cisterna magna with an epidural needle. Swan-Ganz thermistor probes measured the jugular venous and pulmonary artery blood temperatures.

RESULT

The brain temperature decreased from 37.5 +/- 0.3 to 33.0 +/- 0.3 degrees C over an average 150 +/- 45 min cooling period. Stable cool was maintained for 245 +/- 32 min, followed by 165 +/- 50 min for rewarming from 33.5 +/- 0.3 to 37.5 +/- 0.3 degrees C. Jugular, cisterna magna and pulmonary arterial blood (PAB), but not rectal temperature, were close to brain temperature during stable cool. The mean jugular and cisterna magna temperatures were near the brain temperature at 0.1 degrees C higher and 0.1 degrees C lower, respectively. No significant effects of hypothermia were noted on hemodynamics in any phase.

CONCLUSION

Jugular vein temperature, along with cisterna magna and pulmonary artery blood and rectal temperature, reflected brain temperature during hypothermia. The jugular vein and cisterna magna sites more sensitively reflected brain temperature than other sites.

Adjustments in energy expenditure and substrate utilization during late pregnancy and lactation

BACKGROUND

Metabolic adjustments occur during pregnancy and lactation to support fetal growth and milk synthesis; however, the effect of body composition and hormonal milieu on these changes is poorly understood.

OBJECTIVE

We hypothesized that energy metabolism changes during pregnancy and lactation to support fetal growth and milk synthesis, and that body composition and hormonal milieu influence these alterations.

DESIGN

We measured energy expenditure, body composition, and hormone, metabolite, and catecholamine concentrations in 76 women (40 lactating, 36 nonlactating) at 37 wk gestation and 3 and 6 mo postpartum. Total energy expenditure (TEE), basal metabolic rate (BMR), sleeping metabolic rate (SMR), and minimal SMR (MSMR) were measured with room calorimetry. Fat-free mass (FFM) and fat mass were estimated with a 4-component model.

RESULTS

TEE, BMR, SMR, and MSMR were 15-26% higher during pregnancy than postpartum after being adjusted for FFM, fat mass, and energy balance. TEE, SMR, and MSMR were higher in lactating than in nonlactating women. Fasting serum insulin, insulin-like growth factor I, fatty acids, and leptin, and 24-h urinary free norepinephrine, epinephrine, and dopamine correlated positively with TEE, BMR, SMR, and MSMR. In nonlactating women, the respiratory quotient decreased over time, carbohydrate oxidation decreased, and fat oxidation increased. Substrate utilization was not influenced by body composition, fasting serum hormones, or 24-h urinary catecholamines.

CONCLUSIONS

These results indicate increased energy expenditure and preferential use of carbohydrates during pregnancy and lactation. Elevated respiratory quotient and carbohydrate utilization during pregnancy continue during lactation, consistent with preferential use of glucose by the fetus and mammary gland.

Oxidative metabolism in insulin-treated gestational diabetes mellitus

To investigate whether protein, carbohydrate, and fat metabolism was normalized in insulin-treated gestational diabetes mellitus (GDM), eight Hispanic women with GDM and eight healthy controls were studied at 32-36 wk of gestation and 6 wk postpartum. Net substrate utilization was measured using room respiration calorimetry. Exogenous substrate oxidation was determined by 13C recovered in breath CO2 from 13C-labeled leucine, glucose, and Hiolein. Women with GDM had higher 24-h oxygen consumption, carbon dioxide production, total energy expenditure, and basal metabolic rates than controls due to larger body mass. Adjusted for weight or fat-free mass, total energy expenditure, basal metabolic rate, and basal and 24-h whole body net protein, carbohydrate, and fat utilization did not differ between insulin-treated GDM subjects and controls in pregnancy or postpartum. Oxidation of [13C]leucine and [13C]glucose did not differ by group or pregnancy status. Recovery of exogenously administered [13C]Hiolein, a biosynthetic triglyceride, as breath 13CO2 was significantly lower in the GDM group antepartum and postpartum (P = 0.02), indicating lower oxidation of exogenous triglycerides in GDM.

Nitric oxide supplied from a 10% source provides inhaled therapy without lowering inspired oxygen fraction

The authors designed a low-deadspace system to deliver inhaled nitric oxide from a high-concentration (10%) source. Nitric oxide, nitrogen dioxide, and O2 concentrations were compared under simulated inhaled nitric oxide therapy (in vitro) from low (0.08%, 800 ppm) and high (10%, 100,000 ppm) sources of nitric oxide in nitrogen. O2 concentrations remained above 99% and nitrogen dioxide below 3 ppm for nitric oxide delivered at dosages up to 180 ppm from the 10% source. An acute toxicity trial (in vivo) was also performed in nine rabbits mechanically ventilated with 100% O2 for four hours. Six rabbits received 80 ppm nitric oxide from a 10% source and three control rabbits received only O2. Nitric oxide, nitrogen dioxide, and O2 concentrations were monitored in the ventilator circuit. Methemoglobin, arterial blood gases, arterial blood pressure, and heart rate were sampled every hour. At the 80-ppm nitric oxide dose, an average of 1.1 +/- 0.2 ppm of nitrogen dioxide was produced within the ventilator circuit. Arterial methemoglobin in rabbits that received nitric oxide rose by 0.5% from baseline, compared with a 0.2% rise for controls (p = 0.001). The authors conclude that inhaled nitric oxide therapy can be provided from a high-concentration source. Because this system does not reduce inspired O2 fraction, it may be more appropriate than low-source-concentration nitric oxide delivery systems for testing the efficacy of inhaled nitric oxide as an adjunct to optimal conventional medical therapy.

Combined heart rate and activity improve estimates of oxygen consumption and carbon dioxide production rates

Oxygen consumption (VO2) and carbon dioxide production (VCO2) rates were measured by electronically recording heart rate (HR) and physical activity (PA). Mean daily VO2 and VCO2 measurements by HR and PA were validated in adults (n = 10 women and 10 men) with room calorimeters. Thirteen linear and nonlinear functions of HR alone and HR combined with PA were tested as models of 24-h VO2 and VCO2. Mean sleep VO2 and VCO2 were similar to basal metabolic rates and were accurately estimated from HR alone [respective mean errors were -0.2 +/- 0.8 (SD) and -0.4 +/- 0.6%]. The range of prediction errors for 24-h VO2 and VCO2 was smallest for a model that used PA to assign HR for each minute to separate active and inactive curves (VO2, -3.3 +/- 3.5%; VCO2, -4.6 +/- 3%). There were no significant correlations between VO2 or VCO2 errors and subject age, weight, fat mass, ration of daily to basal energy expenditure rate, or fitness. VO2, VCO2, and energy expenditure recorded for 3 free-living days were 5.6 +/- 0.9 ml.min-1.kg-1, 4.7 +/- 0.8 ml. min-1.kg-1, and 7.8 +/- 1.6 kJ/min, respectively. Combined HR and PA measured 24-h VO2 and VCO2 with a precision similar to alternative methods.

Comparison of centrifugal and roller pump hemolysis rates at low flow

We compared in vitro rates of hemolysis for a recently developed centrifugal pump with a conventional roller pump (10-10-00; Stöckert, Munich, Germany). Flow rates of 0.3 L/min and 1 L/min and a pressure of 200 mm Hg were chosen to simulate conditions during neonatal extracorporeal membrane oxygenation (ECMO). There was no significant difference in hemolysis rates between centrifugal and roller pumps (p = 0.57) nor between high and low flow (p = 0.86). The centrifugal pump caused no more blood trauma than the roller pump at the low-flow/high-pressure conditions required for neonatal ECMO. The Nikkiso pump is superior to roller pumps in size and priming volume (25 ml) and may permit development of a smaller and simpler ECMO system.

Energy requirements from infancy to adulthood

To investigate how age and body composition affect energy requirements, the sedentary daily expenditure (SDE) and basal metabolic rate (BMR) of 101 infants, 82 girls, and 27 adults were measured. Energy expenditure was scaled for differences in body size to test the effects of age and body fatness. A power function was superior to linear models. For all subjects, WT0.63 (where WT is weight) or FFM0.63 (where FFM is fat-free mass) explained 94% of the variability in BMR, and WT0.70 or FFM0.70 explained 97% of the variability in SDE. The effects of height and fat mass (kg or % body wt) on BMR and SDE scaled for weight or fat-free mass were age dependent. Best-fitted exponents relating BMR or SDE to body size differed between children (0.40-0.52) and infants (1.04-1.30) (P = 0.001). Human energy requirements from infancy to adulthood appear to be a power, not a linear, function of body weight and composition.

Closed-loop control of carbon dioxide concentration and pressure improves response of room respiration calorimeters

Large room calorimeters are capable of rapid measurements that are usually made in hoods or small rooms. We evaluated the performance gains of four calorimeters constructed with modern control systems, sample gas preparation and data processing. Calibration of the calorimeters and instruments was performed in place, with traceability to international standards. Performance was evaluated by infusion of N2-CO2 gas and 243 24-h studies of individuals. Our subjects included children weighing 20 kg and adults engaged in heavy exercise. Errors for 24-h infusion measurements (n = 23) were -0.34 +/- 1.24% for oxygen consumption rate and 0.11 +/- 0.98% for carbon dioxide production rate. Calorimeter 90% response times were 2 to 6 min over a range of oxygen consumption rates from 100 to > 4000 mL/min. Closed-loop control of supply and exhaust air flows provided consistent 24-h mean CO2 levels (0.39 +/- 0.015%) and pressures (13.2 +/- 4.4 Pa). Room calorimeters operated with closed-loop control can be used for accurate measurement of energy expenditure rate dynamics for a wide range of individuals.

Stroke volume measurement during supine and upright cycle exercise by impedance cardiography

This study evaluated impedance cardiography (ZCG) estimates of stroke volume (SV) during exercise. Seven subjects were studied at rest and during progressive cycle exercise in supine and upright positions. SV was determined by ZCG (SVZCG) during exercise and for the first 5 cardiac cycles following exercise. SVZCG was compared with separate measurements of SV by CO2 rebreathing (SVCO2). Static blood resistivity (p) was measured at each level of exercise. No significant differences were found between supine exercise and immediate post-exercise values for the peak of the first derivative of the impedance change (dZ/dtmax), left ventricular ejection time (LVET), or SVZCG. Small differences in dZ/dtmax and SVZCG, but not LVET, were found in exercise to post-exercise cycling in the upright position. Intra-individual SVZCG and SVCO2 were moderately correlated (upright mean r = 0.64, supine r = 0.42) from rest to 70% of peak VO2. Similar correlations were found between Pulse-O2 (VO2/heart rate, used as an index to SV) and both SVZCG (upright r = 0.73, supine r = 0.57) and SVCO2 (upright r = 0.8, supine r = 0.65). The ZCG parameters dZ/dtmax and LVET correlated better with Pulse-O2 (dZ/dtmax: upright r = 0.92, supine r = 0.73; LVET: upright r = -0.9, supine r = -0.9). SVZCG calculated with the Kubicek equation performed as well as SVCO2. ZCG might be a superior method if the inversely correlated parameters, dZ/dtmax and LVET, were not expressed as a product to calculate SV.

Pre-term infant volume measurements by acoustic plethysmography

An acoustic plethysmograph has been developed to provide routine total body volume measurements of pre-term (1.5-3.0 kg) infants. It operates near 50 Hz and is excited by band-limited 25 Hz span noise. Excitation, measurement, analysis, and environment are computer controlled for greater accuracy, speed, and objectivity in volume determinations. Performance tests produced volume measurements with a mean per cent error (+/- SD) of 0.77 +/- 0.66% for two phantoms with volumes of 2880 and 2130 cm3. Ten, one-minute volume measurements were obtained for 14 infants over a 20 to 30 min period. Their mean density was 1.061 +/- 0.028 g cm-3 and their weight ranged from 1294 to 2025 g.

Fast-response whole body indirect calorimeters for infants

Portable whole body indirect calorimeters were constructed for full-term (2.5- to 8-kg) and preterm (1- to 2.5-kg) infants. A new calibration system significantly increased the accuracy of flowmeters and gas analyzers. Performance tests with N2 and CO2 infusions and butane combustion demonstrated that the error of individual measurements of O2 consumption and CO2 production were within +/- 2%. The measured error was close to the theoretical uncertainty of approximately +/- 1% calculated from test results of the flowmeters and gas analyzers. System response to a step change in butane combustion rate exceeded 90% within 2 min. Error of +/- 2% and response of 2 min are likely to be the practical lower limits for whole body infant indirect calorimeters with current technology. The calorimeters demonstrated a rapid increase in O2 consumption after feeding (preterm infants) and in the transition from non-rapid-eye-movement to rapid-eye-movement sleep stages (full-term infants).

Sleep organization and energy expenditure of breast-fed and formula-fed infants

Sleep organization of infants may be influenced by differences in nutrient intakes from human milk and formula. Because sleep/awake and sleep stage patterns affect energy expenditure, we hypothesized that differences in sleep organization between breast-fed and formula-fed infants might account in part for differences in energy expenditure between feeding groups. Sleep stages and cycling of 4-mo-old breast-fed (n = 10) formula-fed (n = 10) infants were studied with simultaneous measurements of energy expenditure. EEG, electrooculogram, body movement by triaxial accelerometry, heart rate, and oxygen saturation were monitored during an overnight sleep session. Sleep stages, nonrapid eye movement (NREM), and rapid eye movement (REM) were determined. Behavioral observations were recorded by video tape and by a technologist. Oxygen consumption and carbon dioxide production were measured with an indirect calorimeter. Total number and duration of sleep cycles, REM latency, number of NREM and REM epochs, and duration of NREM epochs did not differ between feeding groups. Sleep latency was shorter (p < 0.05) and duration of REM epochs longer (p < 0.01) in the formula-fed group. Formula-fed infants spent a higher percentage of sleep time in REM compared with the breast-fed infants (42 versus 34%) (p < 0.003). Conversely, breast-fed infants spent a higher percentage of sleep time in NREM sleep and their heart rates during sleep were lower (114 versus 126 bpm; p < 0.01). Energy expenditure during REM sleep was 13.0 +/- 4.4% higher than during NREM sleep (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Determining energy expenditure in preterm infants: comparison of 2H(2)18O method and indirect calorimetry

The doubly labeled water (2H(2)18O) method used to estimate total energy expenditure (EETotal) is particularly sensitive to analytic error in preterm infants, because of their high percentage of body water and the high ratio of water flux to CO2 production. To evaluate further use of this method, the EE of 12 preterm infants was measured by indirect calorimetry and 2H(2)18O simultaneously and continuously for 5 days. Initial infant weight, age, and postconceptional age were (means +/- SD) 1,674 +/- 173 g, 4.4 +/- 2.6 wk, and 34.6 +/- 1.6 wk, respectively. The indirect calorimeter system included an air-temperature-controlled chamber and heart rate monitor. EE was measured by indirect calorimetry for 85.6 +/- 4.7% of study time and estimated from the linear regression of heart rate on EE for 14.4 +/- 4.7% of study time. The 2H(2)18O method entailed an initial dose of 100 mg 2H2O and 250 mg 18O/kg and a final dose of 75 mg 18O/kg; urine was collected twice daily. 2H and 18O enrichments were measured by gas-isotope-ratio mass spectrometry. EE was calculated from measured 2H and 18O dilution spaces (NH, NO), turnover rates (kH, kO), and measured respiratory quotient. The ratio of 2H to 18O dilution spaces was 1.01 +/- 0.01 and the ratio of kO to kH was 1.16 +/- 0.04. Estimation of EE from 2H(2)18O and indirect calorimetry agreed within 1%, although individual variability in methods was large.