Metabolic rate measurement system

The Metabolic Rate Measurement System (MRMS) is an uncomplicated and accurate apparatus for measuring oxygen consumption and carbon dioxide production of a test subject. From this one can determine the subject's metabolic rate for a variety of conditions, such as resting or light exercise. MRMS utilizes an LSI/11-03 microcomputer to monitor and control the experimental apparatus

Avian Song Complexity is Associated With High Field Metabolic Rate

Question: Is the production of bird song costly? Analyses of oxygen consumption during singing provided conflicting results. Data studied: Data on 28 passerine species with quantitative information on song complexity and field metabolic rate, which reflects energy requirements of wild birds. The phylogenetic relationship data came from molecular sources. Search method: Generalized least squares models to control for phylogenetic associations. First, we adjusted field metabolic rate to body size, and calculated the phylogenetic correlation between relative field metabolic rate and measures of song complexity. Second, we compared song complexity of birds inhabiting and and mesic environments. Conclusion: A measure of short-term song complexity, relative syllable repertoire size, is positively and significantly related to relative field metabolic rate. Species from and habitats have less complex songs than species from mesic habitats

Metabolic Rate of Cherax Quadricarinatus

Temperature is the most prominent factor that influence metabolic rate of aquatic animals. In general, the increasing temperature of 10 degrees Celsius will improve metabolic rate two-fold. Therefore, this research aim is to examine the metabolic rate and Q10 value of crayfish. The metabolic rate of crayfish (Cherax quadricarinatus) was examined by determining oxygen consumption rates using caulorimetric respirometer. The oxygen consumption rates of Cherax quadricarinatus which acclimated at 23_C and 31_C is at around 0.52 and 0.7 uL/g/min respectively. Furthermore, the Q10 value of crayfish between 23_C and 31_C is 1.47. The oxygen consumption and Q10 value of crayfish is different compare with other aquatic invertebrate and ectotherms

A model of oxygen dynamics in the cerebral microvasculature and the effects of morphology on flow and metabolism

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.The cerebral microvasculature plays a vital role in adequately supplying blood to the brain. Determining the health of the cerebral microvasculature is important during pathological conditions, such as stroke and dementia. Recent studies have shown the complex behaviour of cerebral metabolic rate with transit time distribution. In this paper, we extend a recently developed technique to solve for residue function and transit time distribution in an existing physiologically accurate model of the cerebral microvasculature to calculate cerebral metabolism. We present the mathematical theory based on solving the mass transport equation followed by results of the simulations. It is found that oxygen extraction fraction and cerebral metabolic rate are dependent on both mean and heterogeneity of the transit time distribution. For changes in cerebral blood flow, a positive correlation can be observed between mean transit time and oxygen extraction fraction, and a negative correlation between mean transit time and metabolic rate of oxygen. The metabolic rate is thus affected more significantly by cerebral blood flow than oxygen extraction fraction. A negative correlation can also be observed between transit time heterogeneity and the metabolic rate of oxygen for a constant cerebral blood flow. The heterogeneity of the transit time distribution also has an effect on the response of oxygen extraction fraction and cerebral metabolic rate to sudden changes. These results provide information on the role of the cerebral microvasculature and its effects on flow and metabolism. They thus open up the possibility of obtaining additional valuable clinical information for diagnosing and treating cerebrovascular diseases

Metabolic rate meter and method

A method is described for measuring the dynamic metabolic rate of a human or animal. The ratio of the exhaled carbon dioxide to a known amount of C(13)02 introduced into the exhalation is determined by mass spectrometry. This provides an instantaneous measurement of the carbon dioxide generated

Effect of deuterium on the circadian period and metabolism in wild-type and tau mutant Syrian hamsters

Homozygous tau mutant Syrian hamsters (tau-/-) have a free-running circadian period (τ) around 20 h and a proportionally higher metabolic rate compared with wild-type hamsters (tau+/+) with a period of circa 24 h. In this study, we applied deuterium oxide (D2O) to hamsters to test whether deuteration affects the circadian period of locomotor activity and metabolic rate in both genotypes. Running wheel activity and the metabolic rate were measured in constant illumination before, during, and after administration of 25% deuterium in drinking water. Wild-type hamsters lengthened their circadian period by 1.19 h (SD = 0.29 h) due to D2O application and tau-/- hamsters by 1.20 h (SD = 0.39 h). Deuteration changed neither the amount of activity nor the duration of activity phase (α) in either genotype. The mass specific average metabolic rate (AMR, the oxygen consumption over 24 h) and the mass specific resting metabolic rate (RMR) did not differ during deuteration compared with non-deuteration conditions for either genotype. Both with and without D2O, tau-/- hamsters had higher metabolic rates than tau+/+ hamsters. There was no correlation between changes in the circadian period of locomotor activity and metabolic rates caused by D2O.

Age and Huddling as Determinants of Metabolic Rate in Grasshopper Mice (Onychomys leucogaster)

The metabolic rates of grasshopper mice (Onychomys leucogaster) were determined every third day from birth to adulthood. Metabolic rates were quantitated by measuring oxygen consumption in an open circuit system. There was a rapid fall in oxygen consumption from the third day after birth until the ninth day. Mice which were housed separately assumed a constant metabolic rate at an earlier age than mice which were kept with litter-mates. The greatest increases in metabolism occurred when immature mice were separated from litter-mates for oxygen consumption determinations. It is concluded that huddling plays an important role in reducing the metabolic rate of young grasshopper mice

The relationship between metabolic rate and sociability is altered by food-deprivation

Individuals vary in the extent to which they associate with conspecifics, but little is known about the energetic underpinnings of this variation in sociability. Group-living allows individuals to find food more consistently, but within groups, there can be competition for food items. Individuals with an increased metabolic rate could display decreased sociability to reduce competition. Long-term food deprivation (FD) may alter any links between sociability and metabolic rate by affecting motivation to find food. We examined these issues in juvenile qingbo carp Spinibarbus sinensis, to understand how FD and metabolic rate affect sociability. Like many aquatic ectotherms, this species experiences seasonal bouts of FD. Individuals were either: (i) food-deprived for 21 days; or (ii) fed a maintenance ration (control). Fish from each treatment were measured for standard metabolic rate (SMR) and tested for sociability twice: once in the presence of a control stimulus shoal and once with a food-deprived stimulus shoal. Control individuals ventured further from stimulus shoals over a 30-min trial, while food-deprived fish did not change their distance from stimulus shoals as trials progressed. Control fish with a higher SMR were least sociable. Well-fed controls showed decreased sociability when exposed to food-deprived stimulus shoals, but there was evidence of consistency in relative sociability between exposures to different shoal types. Results contrast with previous findings that several days of fasting causes individuals to decrease associations with conspecifics. Prolonged FD may cause individuals to highly prioritize food acquisition, and the decreased vigilance that would accompany continuous foraging may heighten the need for the antipredator benefits of shoaling. Conversely, decreased sociability in well-fed fish with a high SMR probably minimizes intraspecific competition, allowing them to satisfy an increased energetic demand while foraging. Together, these results suggest that FD – a challenge common for many ectothermic species – can affect individual sociability as well as the attractiveness of groups towards conspecifics. In addition, the lack of a link between SMR and sociability in food-deprived fish suggests that, in situations where group membership is linked to fitness, the extent of correlated selection on metabolic traits may be context-dependent

High cycling cadence reduces carbohydrate oxidation at given low intensity metabolic rate

Cycling cadence (RPM)-related differences in blood lactate concentration (BLC) increase with increasing exercise intensity, whilst corresponding divergences in oxygen uptake (VO2) and carbon dioxde production (VCO2) decrease. We tested the hypothesis, that a higher RPM reduces the fraction (%) of the VO2 used for carbohydrate oxidation (relCHO) at a given BLC. Eight males (23.9 +/- 1.6 yrs; 177 +/- 3 cm; 70.3 +/- 3.4 kg) performed incremental load tests at 50 and 100 RPM. BLC, VO2 and VCO2 were measured. At respiratory exchange ratios (RER) <1, relCHO were calculated and the constant determining 50% relCHO (kCHO) was approximated as a function of the BLC. At submaximal workload, VO2 and RER were lower (p<0.001) at 50 than at 100 RPM. No differences were observed in VO2peak (3.96 +/- 0.22 vs. 4.00 +/ 0.25 l min-1) and RERpeak (1.18 +/- 0.02 vs. 1.15 +/- 0.02). BLC was lower (p<0.001) at 50 than at 100 RPM irrespective of cycling intensity. At 50 RPM, kCHO (4.2 +/- 1.4 (mmol l-1)3) was lower (p<0.05) than at 100 RPM (5.9 +/- 1.9 (mmol l-1)3). This difference in kCHO reflects a reduced CHO oxidation at a given BLC at 100 than at 50 RPM. At a low exercise intensity, a higher cycling cadence can substantially reduce the reliance on CHO at a given metabolic rate and/or BLC