Buffer systems in the rumen of sheep. I. pH and bicarbonate concentration in relationship to pCO2.

1955 ◽  
Vol 6 (1) ◽  
pp. 115 ◽  
Author(s):  
AW Turner ◽  
VE Hodgetts
Keyword(s):  
Carbon Dioxide ◽  
Carbonic Acid ◽  
High Pco2 ◽  
Bicarbonate Concentration ◽  
Bulk Fluid ◽  
Ruminal Fluid ◽  
Arterial Blood ◽  
Wide Range ◽  
The Relationship ◽  
Hasselbalch Equation

Experiments are described which emphasize the importance of avoiding loss of carbon dioxide when estimating the pH or bicarbonate concentration of ruminal fluid. The high pCO2 of ruminal fluid is stressed; this may be 10 times or more as great as that of arterial blood. The relationship between pCO2, pH, and [HCO3-] was examined in terms of the Henderson-Hasselbalch equation over a wide range of pCO2. From this, the pK1' of the carbonic acid system in four ruminal fluids was determined as 6.21-6.28, mean 6.25. The higher pH of saliva-free samples of ruminal fluid withdrawn by suction through a tube passed down the oesophagus, as compared with that of the bulk fluid obtained through a ruminal fistula, is considered to be due to loss of carbon dioxide during collection. A better estimate of intraruminal pH is obtained, even when salivary contamination occurs, if such samples are equilibrated with a sample of the animal's ruminal gas; if this is not practicable, an arbitrary gas mixture of high pCO2, e.g. 50 per cent. carbon dioxide and nitrogen, may be used.

Which value for the first dissociation constant of carbonic acid should be used in biological work?

1991 ◽  
Vol 260 (5) ◽  
pp. C1113-C1116 ◽  
Author(s):  
R. W. Putnam ◽  
A. Roos
Keyword(s):  
Ionic Strength ◽  
Activity Coefficient ◽  
Dissociation Constant ◽  
Carbonic Acid ◽  
Mass Action ◽  
Bicarbonate Concentration ◽  
Apparent Dissociation Constant ◽  
Logarithmic Form ◽  
Ion Activity ◽  
Hasselbalch Equation

The apparent first dissociation constant of carbonic acid has been defined in different ways in the literature. Harned and co-workers (8-10) have defined it in terms of molalities of the participating species, including H ions: Ks = mHmHCO3/mCO2. In contrast, Hastings and Sendroy have defined an apparent constant in which acidity is expressed as H ion activity: K'1 = aHmHCO3/mCO2. These constants differ by a factor gamma H, the activity coefficient of H ions at the prevailing ionic strength. Therefore, pK'1 is greater than pKs by an amount equal to -log gamma H, which, at mu = 0.16 M, is approximately 0.1. It is important that the correct value for the apparent dissociation constant or its logarithmic form be entered in the mass action expression or in the Henderson-Hasselbalch equation in order to prevent significant errors in the computation by means of these equations of quantities that cannot be directly measured. Specifically, for the derivation of bicarbonate concentration from PCO2 and pH (-log aH), pK'1 is to be used and not an uncorrected pKs.

A Model for the Relationship Between the Arterial Pressure and the Heart Period

1989 ◽  
Vol 111 (4) ◽  
pp. 336-341
Author(s):  
F. Iacovelli ◽  
M. Napolitano ◽  
A. Federici ◽  
G. Sorrentino
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Arterial Blood ◽  
Average Blood Pressure ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Heart Cycle ◽  
Physiological Values ◽  
Experimental Values ◽  
The Relationship

This paper provides a simple model for predicting the relationship between steadystate heart rate and arterial blood pressure. Two current state-of-the-art models of the cardiovascular system as a pump operating in its circuit are reformulated and combined in order to highlight the role of the duration of the heart cycle. The proposed model establishes that the cardiac cycle lengthens linearly with the inverse of the average blood pressure. Experimental data are reported for sixteen preoperated conscious dogs resting quietly on their sides. Vagal and sympathetic blocks have been produced in four dogs in order to obtain a wide range of sympathetic and parasympathetic tones, namely, to cover the entire range of physiological values of the heart rate. For these dogs a comparison between the experimental values and the theoretical predictions shows a good agreement, the results of the linear regression model being statistically significant at the p = 0.001 level for three dogs and at the p = 0.01 level for the fourth dog.

CERTAIN ASPECTS OF THE RENAL REGULATION OF BODY COMPOSITION

PEDIATRICS ◽  
1954 ◽  
Vol 14 (6) ◽  
pp. 567-572
Author(s):  
ROBERT E. COOKE
Keyword(s):  
Carbon Dioxide ◽  
Extracellular Space ◽  
Carbonic Acid ◽  
Plasma Concentrations ◽  
Extracellular Volume ◽  
Extracellular Fluid ◽  
Carbon Dioxide Tension ◽  
Plasma Sodium ◽  
Renal Tubules ◽  
Bicarbonate Concentration

THE pH of extracellular fluid is determined by the ratio of the plasma concentrations of bicarbonate ion to carbonic acid, as given in the classical Henderson-Hasselbach equation. [See Equation in Source Pdf] The denominator the carbonic acid concentration, [H2CO3], is proportional to the carbon dioxide tension of the blood. The carbon dioxide tension (pCO2) is primarily dependent upon respiratory function, since metabolism (hence carbon dioxide production) is relatively constant. The numerator of the equation—the bicarbonate concentration of extracellular fluid—is determined by the difference between nonvolatile cations and anions. Since there are almost limitless quantities of bicarbonate available to the organism from cell metabolism, [See Equation in Source Pdf] bicarbonate concentration must change whenever nonvolatile cation (largely sodium) is altered in relation to nonvolatile anion (largely chloride). Thus in most states extracellular bicarbonate concentration is dependent upon the ratio of sodium to chloride in extracellular fluid. The quantity of water filtered at the glomeruli and reabsorbed by the renal tubules each day is approximately 15 times the extracellular volume. The quantity of sodium chloride filtered and reabsorbed daily is approximately 15 times that contained in the extracellular space and 150 times that usually ingested and excreted each day. Therefore, the ratio of plasma sodium to chloride in any steady state is determined by the composition of the renal tubular reabsorbate, as Cushny pointed over 30 years ago. In a sense the kidney perfuses the extracellular space with large quantities of tubular reabsorbate. Tubular reasorbate—the net quantity of materials reabsorbed by the tubules. This term is analogous to glomerular filtrate—the quantity of materials filtered by the glomeruli.

Coupling of NaHCO3 and NaCl reabsorption in dog kidneys during changes in plasma PCO2

1979 ◽  
Vol 236 (3) ◽  
pp. F232-F239 ◽  
Author(s):  
O. Mathisen ◽  
T. Monclair ◽  
M. Raeder ◽  
F. Kiil
Keyword(s):  
Tubular Reabsorption ◽  
Bicarbonate Concentration ◽  
Molar Ratios ◽  
Bicarbonate Reabsorption ◽  
Wide Range ◽  
Proximal Tubular ◽  
Anesthetized Dogs ◽  
The Relationship ◽  
Proximal Tubular Reabsorption ◽  
Glomerulotubular Balance

To study the relationship between proximal tubular reabsorption of bicarbonate, sodium, and chloride, the effects of changes in plasma PCO2 were examined in anesthetized dogs. Distal tubular reabsorption was inhibited by ethacrynic acid; plasma bicarbonate concentration was kept constant at 33.4 +/- 0.3 mM; glomerular filtration rate (GFR) was varied over a wide range to examine glomerulotubular balance (constant fractional reabsorption). Hypercapnia (PCO2, 112.0 +/- 2.5 mmHg) increased bicarbonate reabsorption by about 30%, and hypocapnia (PCO2, 19.8 +/- 0.6 mmHg) decreased reabsorption of bicarbonate by more than 50% and altered reabsorption of sodium, chloride, and bicarbonate in the molar ratios 2.7:1.6:1, respectively. During hypercapnia the range of glomerulotubular balance was extended to a GFR 125% of control. During hypocapnia glomerulotubular balance was present only at GFR below 50% of control; reabsorption of bicarbonate sodium, and chloride was constant at GFR exceeding 50% of control. During metabolic acidosis hypercapnia had no significant effect on reabsorption of bicarbonate, sodium, and chloride. These observations support the hypothesis that bicarbonate reabsorption is the main driving force for osmotic reabsorption of water and NaCl in the proximal tubules.

Environmental regulation of the oxygen effect on apparent photosynthesis in wheat

1973 ◽  
Vol 51 (5) ◽  
pp. 841-853 ◽  
Author(s):  
P. A. Jolliffe ◽  
E. B. Tregunna
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Environmental Regulation ◽  
Environmental Conditions ◽  
Compensation Point ◽  
Oxygen Effect ◽  
Exchange System ◽  
Wide Range ◽  
Gas Exchange System ◽  
The Relationship

A closed gas exchange system was used to survey the apparent rates of photosynthesis by young wheat shoots in a wide range of O2 concentrations (O2), CO2 concentrations (CO2), temperatures (T), and radiant flux densities. The results are expressed graphically and by equations. The carbon dioxide compensation point (ΓH) conformed to the equation ΓH = O2e(0.0428T − 12.1). The relationship between the apparent rates of photosynthesis in the presence (PH) and absence (PL) of inhibitory concentrations of oxygen was described by the equation PH = PLk loge(CO2/ΓH) where k was independent of the prevailing environmental conditions and [Formula: see text].

scholarly journals Analysis of the application and impact of carbon dioxide media on the corrosion state of oil and gas facilities

2021 ◽  
Vol 250 ◽  
pp. 578-856
Author(s):  
Rafael Kantyukov ◽  
Dmitry Zapevalov ◽  
Ruslan Vagapov
Keyword(s):  
Carbon Dioxide ◽  
Oil And Gas ◽  
Carbonic Acid ◽  
Acid Corrosion ◽  
Co2 Storage ◽  
Hydrocarbon Production ◽  
Partial Pressures ◽  
Wide Range ◽  
Corrosion Of Steel ◽  
Corrosion State

Products of several currently operated production facilities (Bovanenkovskoye, Urengoyskoye oil and gas condensate fields, etc.) contain an increased amount of corrosive CO2. Effect of CO2 on the corrosion of steel infrastructure facilities is determined by the conditions of its use. Carbon dioxide has a potentially wide range of applications at oil and gas facilities for solving technological problems (during production, transportation, storage, etc.). Each of the aggregate states of CO2 (gas, liquid and supercritical) is used and affects the corrosion state of oil and gas facilities. Article analyzes the results of simulation tests and evaluates the corrosion effect of CO2 on typical steels (carbon, low-alloy and alloyed) used at field facilities. The main factors influencing the intensity of carbonic acid corrosion processes in the main conditions of hydrocarbon production with CO2, storage and its use for various technological purposes are revealed. Development of carbon dioxide corrosion is accompanied and characterized by the localization of corrosion and the formation of defects (pitting, pits, etc.). Even alloyed steels are not always resistant in the presence of moisture and increased partial pressures of CO2, especially in the presence of additional factors of corrosive influence (temperature, aggressive impurities in gas, etc.).

Indications for measurement of total carbon dioxide in arterial blood.

1988 ◽  
Vol 34 (8) ◽  
pp. 1650-1652 ◽  
Author(s):  
G J Kost ◽  
J K Trent ◽  
D Saeed
Keyword(s):  
Carbon Dioxide ◽  
Blood Sampling ◽  
Total Carbon ◽  
Carbon Dioxide Content ◽  
Arterial Blood Sampling ◽  
Arterial Blood ◽  
Arterial Ph ◽  
Therapeutic Decisions ◽  
Technical Artifacts ◽  
Hasselbalch Equation

Abstract There is increasing evidence of variability in pK1', the practical dissociation coefficient used in the Henderson-Hasselbalch equation to calculate arterial bicarbonate from measurements of arterial pH and pco2. The case presented here illustrates not only potential technical artifacts in arterial blood sampling, which can confuse, but also irreconcilable differences in the values of calculated arterial bicarbonate vs measured arterial and venous total carbon dioxide (carbon dioxide content). Measurements of total carbon dioxide in arterial blood will resolve such conflicts, particularly for acutely ill patients, and will reflect the correct bicarbonate measurements for use in therapeutic decisions.

scholarly journals Measurement of Heat Release Rate by Carbon Dioxide Generation Method for Methane Fire

2020 ◽  
Vol 34 (2) ◽  
pp. 1-6
Author(s):  
Sung-Chan Kim
Keyword(s):  
Carbon Dioxide ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Oxygen Depletion ◽  
Rate Measurement ◽  
Complementary Method ◽  
Wide Range ◽  
The Relationship ◽  
Key Parameter

The energy released by various burning material has a wide range of its magnitude and transient characteristics, the measurement of the heat release rate(HRR) has been considered as one of the most challenging issue among the parameters related to fire. This study compares the measured HRR calculated by the oxygen consumption (OC) method and the carbon dioxide generation (CDG) method using a laboratory-scale fire calorimeter. The feasibility of the CDG method is examined by analyzing the relative error. The relationship between the oxygen depletion factor and CO<sub>2</sub> mass flow rate, which is a key parameter in HRR calculations, showed strong linearity at 6 % for the methane burner fire. The contribution of HRR by CO was less than 7% compared with the of HRR by CO<sub>2</sub> in the CDG calculation method. The linearity of the OC and CDG methods with respect to HRR of the referenced methane burner in a quasi-steady state was less than 1%; this indicates that the CDG method can be utilized as a complementary method in heat release rate measurement.

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