Respiratory quotient calculation

Respiratory Quotient Data from Human Studies Protein Oxidation and the Respiratory Quotient Calculating Energy Expenditures... 

Li, X, Jin, L. Z., Wang, S. Zhu, J. 2010. Respiratory quotient calculation of the human body at a confined space in coal mines. Journal of University of Science and Technology Beijing, 32, 963-967. 

The respiratory quotient (RQ) is often used to estimate metabolic stoichiometry. Using quasi-steady-state and by definition of RQ, develop a system of two linear equations with two unknowns by solving a matrix under the following conditions the coefficient of the matrix with yeast growth (y = 4.14), ammonia (yN = 0) and glucose (ys = 4.0), where the evolution of C02 and biosynthesis are very small (o- = 0.095). Calculate the stoichiometric coefficient for RQ =1.0 for the above biological processes ... 

Data from indirect calorimetry can also be used to determine a respiratory quotient. Values greater than 1 suggest overfeeding, whereas values less than 0.7 suggest a ketogenic diet, fat gluconeogenesis, or ethanol oxidation. Respiratory quotient (RQ) is calculated as follows ... 

Respiratory quotient (qC02) Calculation from soil respiration divided microbial biomass carbon Indicates activity of microbial biomass determined in nonstandard laboratory with specialized equipment when high, considered an indication of stress on microbial biomass Rice et al. (1996)... 

Software sensors are virtual sensors which calculate the desired variable or parameter from related physical measurements [58]. In other words, there must always be a model available that relates reliably the measured variable with the target variable or parameter. Normally, measured variables are easily measurable effects that are caused and influenced by the target. The most prominent software sensor is the respiratory quotient (RQ-value) which characterizes the physiological state of a culture. However, its determination can be tricky (see Sect. 5). 

Indirect calorimetry provides the ability to measure the relative contribution of macronutrients toward energy use. The measurements of expired carbon dioxide and consumed oxygen are used to calculate respiratory quotient (RQ). An RQ of 1.0 indicates use of carbohydrate solely, an RQ of 0.7 indicates use of fat solely, whereas an RQ of 0.85 indicates mixed use of macronutrients. Data in rats demonstrates a significant increase in using fat as an energy substrate following DAG oil infusion (gastric) as observed by a decreased respiratory quotient value between 3-5 hours post-infusion (15). 

The main goal of this chapter is to leam how to determine the body s overall style of energy metabolism, via respiratory quotient (RQ) measure-ntents, and to derive the daily energy requirement. A view of the stoichiometries of the glycolytic pathway, Krebs cycle, and pathways of fatty acid synthesis and oxidation will allow RQ calculations for each individual pathway. Glycolysis and the Krebs cycle were presented in Chapter 4, Fatt> add synthesis and oxidation are detailed here. The locations, at points along various metabolic pathways, whereCO2 is produced (in the Krebs cycle) and Oj is consumed (in the respiratory chain), are points of focus in this chapter... 

FIGURE 5.16 Respiratory quotient measurements of human subjects (O) food quotient values ( ). Human subjects consumed a low-fat diet for 6 days, followed by a high-fat diet for 7 days. Subjects lived inside separate respiratory chambers for days 4-10, then left the chambers, and returned for days 12-14. Each respiratory chamb was a small room ventilated at a measured rate with air. In-going air was sampled and measured every 15 min, and outgoing air was sampled and measured every 5 min, for the entire period that the subjects lived in the chambers. The RQ values for each subject was calculated for each day, as indicated in the figure. (Redrawn with permission from Schrauwen et al, 1997.)... 

For each gram of dry matter (CgHi206), which is oxidized, 15.7 kJ of heat is produced. Equation 27.33 provides a simple way of calculating the heat production from the CO2 production. According to Equation 27.33 the respiratory quotient (ratio of oxygen consumption to carbon dioxide production) is equal to 1.0. However, measured quotients frequently deviate from 1.0 [69]. 

In one of the most remarkable scientific collaborations, Lavoisier, the chemist, and Laplace, the physicist, carefully measured oxygen intake and CO2 output in laboratory animals, and were thus able to calculate the respiratory quotient ... 

Animals do not normally obtain energy exclusively from either carbohydrate or fat. They oxidise a mixture of these (and protein). Consequently, in order to apply the appropriate thermal equivalent, it is necessary to know how much of the oxygen is used for oxidation of each nutrient. The proportions are calculated from what is known as the respiratory quotient (RQ).This is the ratio between the volume of carbon... 

It can be calculated that, if the respiratory quotient is 0-7 (i.e. 1 volume of O2 is utilized for every 0-7 volume of CO2 produced), all the H resulting from the conversion of CO2 + H20 H2C03 + HCOs" can be buffered by haemoglobin without any alteration in pH. 

Measurement of the respiratory quotient and urinary excretion of urea thus permits calculation of the relative amounts of fat, carbohydrate and protein being metabolized. In the fasting state (section 5.3.2), when a relatively large amount of fat is being used as a fuel, the respiratory quotient is around 0.8-0.85 after a meal, when there is more carbohydrate available to be metabolized (section 5.3.1), the respiratory quotient... 

Estimating the average respiratory quotient over the period from the proportions of fat, carbohydrate and protein in the diet and allowing for any changes in body fat permits calculation of the total amount of oxygen that has been consumed, and hence the total energy expenditure over a period of 2—3 weeks. 

Therefore, if we utilize the equation for the catabolism of carbohydrates, we can calculate a respiratory quotient ... 

In evaluating an effect of hiamic substances on respiration, both uptake and CO output should be considered and the Respiratory Quotient CO iO calculated. Although the value of the Respiratory Quotient (R.Q.)... 

Indirect measurement via computers appears to be a viable alternative to measurement involving sampling. Certain sensor information can be combined to give additional information such as oxygen-uptake rate, carbon-dioxide evolution rate, and respiratory quotient. These measurements can be thought of as gateway measurements because they make possible the calculation of additional information (Table 24.3). ... 

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