scholarly journals Use of [2-14C]glucose and [5-14C]glucose for evaluating the mechanism and quantitative significance of the ‘liver-cell’ pentose cycle

1980 ◽  
Vol 188 (3) ◽  
pp. 847-857 ◽  
Author(s):  
J P Longenecker ◽  
J F Williams
Keyword(s):  
Steady State ◽  
Glucose Metabolism ◽  
Pentose Phosphate ◽  
Exchange Reactions ◽  
Triose Phosphate ◽  
State Measurement ◽  
Isotopic Equilibration ◽  
Second Procedure ◽  
Quantitative Contribution ◽  
Steady State Measurement

1. Expressions are derived for the steady-state measurement of the quantitative contribution of the liver-type pentose phosphate cycle to glucose metabolism by tissues. One method requires the metabolism of [5-14C]glucose followed by the isolation and degradation of glucose 6-phosphate. The second procedure involves the metabolism of [2-14C]glucose and the isolation and degradation of a triose phosphate derivative, usually lactate or glycerol. 2. Measurements of 14C in C-2 and C-5 of glucose 6-phosphate are required and the values of the C-2/C-5 ratios can be used to calculate the quantitative contribution of the L-type pentose cycle in all tissues. 3. The measurement of 14C in C-1, C-2 and C-3 of triose phosphate derivatives can be used to calculate the quantitative contribution of the L-type pentose cycle relative to glycolysis. 4. The effect of transaldolase and transketolase exchange reactions, reactions of gluconeogenesis and non-oxidative formation of pentose 5-phosphate, isotopic equilibration of triose phosphate pools and isotopic equilibration of fructose 6-phosphate and glucose 6-phosphate, which could interfere with a clear interpretation of the data using [2-14C]- and [5-14C]glucose are discussed.

scholarly journals Quantitative measurement of the L-type pentose phosphate cycle with [2-14C]glucose and [5-14C]glucose in isolated hepatocytes

1980 ◽  
Vol 188 (3) ◽  
pp. 859-865 ◽  
Author(s):  
J P Longenecker ◽  
J F Williams
Keyword(s):  
Glucose Metabolism ◽  
Exchange Reaction ◽  
Quantitative Measurement ◽  
Distribution Patterns ◽  
Isolated Hepatocytes ◽  
Pentose Phosphate ◽  
Triose Phosphate ◽  
Pentose Phosphate Cycle ◽  
Quantitative Contribution ◽  
Pentose Pathway

1. Investigations of the mechanism of the non-oxidative segment of the pentose phosphate cycle in isolatd hepatocytes by prediction-labelling studies following the metabolism of [2-14C]-, [5-14C]- and [4,5,6-14C]glucose are reported. The 14C distribution patterns in glucose 6-phosphate show that the reactions of the L-type pentose pathway in hepatocytes. 2. Estimates of the quantitative contribution of the L-type pentose cycle are the exclusive form of the pentose cycle to glucose metabolism have been made. The contribution of the L-type pentose cycle to the metabolism of glucose lies between 22 and 30% in isolated hepatocytes. 3. The distribution of 14C in the carbon atoms of glucose 6-phosphate following the metabolism of [4,5,6-14C]- and [2-14C]glucose indicate that gluconeogenesis from triose phosphate and non-oxidative formation of pentose 5-phosphate do not contribute significantly to randomization of 14C in isolated hepatocytes. The transaldolase exchange reaction between fructose 6-phosphate and glyceraldehyde 3-phosphate is very active in these cells.

Steady State Measurement of Oxygenation Capacity

1985 ◽  
Vol 17 (2-3) ◽  
pp. 303-311
Author(s):  
Kees de Korte ◽  
Peter Smits
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Plug Flow ◽  
Usual Method ◽  
Steady State Method ◽  
State Measurement ◽  
Flow Systems ◽  
Air System ◽  
State Method ◽  
Steady State Measurement

The usual method for OC measurement is the non-steady state method (reaeration) in tapwater or, sometimes, in activated sludge. Both methods are more or less difficult and expensive. The steady state method with activated sludge is presented. Fundamentals are discussed. For complete mixed aeration tanks, plug flow systems with diffused air aeration and carousels the method is described more in detail and the results of measurements are presented. The results of the steady state measurements of the diffused air system are compared with those of the reaeration method in tapwater. The accuracy of the measurements in the 3 systems is discussed. Measurements in other aeration systems are described briefly. It is concluded that the steady state OC measurement offers advantages in comparison with the non-steady state method and is useful for most purposes.

scholarly journals Steady-state measurement of the effective particle density of cigarette smoke

2014 ◽  
Vol 75 ◽  
pp. 9-16 ◽  
Author(s):  
Tyler J. Johnson ◽  
Jason S. Olfert ◽  
Ross Cabot ◽  
Conor Treacy ◽  
Caner U. Yurteri ◽  
...  
Keyword(s):  
Steady State ◽  
Cigarette Smoke ◽  
Particle Density ◽  
State Measurement ◽  
Effective Particle ◽  
Steady State Measurement

scholarly journals A gas turbine diagnostic approach with transient measurements

2003 ◽  
Vol 217 (2) ◽  
pp. 169-177 ◽  
Author(s):  
Y. G. Li
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Operating Conditions ◽  
Diagnostic Methods ◽  
Transient Processes ◽  
Diagnostic Approach ◽  
Turbine Performance ◽  
State Measurement ◽  
Transient Measurement ◽  
Steady State Measurement

Most gas turbine performance analysis based diagnostic methods use the information from steady state measurements. Unfortunately, steady state measurement may not be obtained easily in some situations, and some types of gas turbine fault contribute little to performance deviation at steady state operating conditions but significantly during transient processes. Therefore, gas turbine diagnostics with transient measurement is superior to that with steady state measurement. In this paper, an accumulated deviation is defined for gas turbine performance parameters in order to measure the level of performance deviation during transient processes. The features of the accumulated deviation are analysed and compared with traditionally defined performance deviation at a steady state condition. A non-linear model based diagnostic method, combined with a genetic algorithm (GA), is developed and applied to a model gas turbine engine to diagnose engine faults by using the accumulated deviation obtained from transient measurement. Typical transient measurable parameters of gas turbine engines are used for fault diagnostics, and a typical slam acceleration process from idle to maximum power is chosen in the analysis. The developed diagnostic approach is applied to the model engine implanted with three typical single-component faults and is shown to be very successful.

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