A modified rebreathing technique using an infrared gas analyzer

1996 ◽  
Vol 80 (4) ◽  
pp. 1258-1262 ◽  
Author(s):  
K. W. Barazanji ◽  
M. Ramanathan ◽  
R. L. Johnson ◽  
C. C. Hsia
Keyword(s):  
Healthy Subjects ◽  
Fast Response ◽  
Gas Mixture ◽  
Paired Comparisons ◽  
Diffusing Capacity ◽  
Gas Analyzer ◽  
Cardiopulmonary Function ◽  
The Cost ◽  
Infrared Gas Analyzer ◽  
Ir Analyzer

To lower the cost and improve accessibility of the rebreathing technique for measuring cardiopulmonary function during exercise, we implemented a fast-response infrared (IR) gas-analyzer system to simultaneously measure lung diffusing capacity, cardiac output lung tissue volume, and lung volume by a rebreathing technique in five healthy subjects at rest and during steady-state exercise. Interferences by water vapor and CO2 on the analyzer were determined and corrected for. During rebreathing, a gas mixture of 0.4% C2H2-0.3% CH4-9% He-30% O2, and either 0.3% C18O or 0.3% C16O in a balance of N2 was simultaneously sampled by both a mass spectrometer and the IR analyzer, permitting paired comparisons. Measurements obtained by the two devices were not significantly different. We conclude that this modified rebreathing technique using the IR analyzer is accurate for the measurement of cardiopulmonary function at rest and during exercise.

An open gas-exchange system for the simultaneous measurement of the CO2 and 14CO2 fluxes from leaves

1971 ◽  
Vol 49 (8) ◽  
pp. 1299-1313 ◽  
Author(s):  
L. J. Ludwig ◽  
D. T. Canvin
Keyword(s):  
Gas Exchange ◽  
Ionization Chamber ◽  
Specific Activity ◽  
Gas Mixture ◽  
Gas Analyzer ◽  
Constant Composition ◽  
Exchange System ◽  
Steady Rate ◽  
Gas Exchange System ◽  
Infrared Gas Analyzer

An open gas exchange system that uses an infrared gas analyzer and an ionization chamber to measure CO2 and 14CO2 is described. The system will continuously measure the CO2 and 14CO2 exchange from a leaf within 30 s after the 14CO2 gas mixture is supplied to the leaf. Measurements are obtained under steady rate conditions since the 14CO2 gas mixture is supplied at a constant composition from pressurized cylinders. Methods of determining true photosynthesis, apparent photosynthesis, CO2 evolution, and the specific activity of the 14CO2 evolved are clearly described. The rate of CO2 evolution in the light was not affected by the CO2 concentration and the evolved CO2 was derived from the early products of photosynthesis.

Nonlinear increases in diffusing capacity during exercise by seated and supine subjects

1981 ◽  
Vol 51 (4) ◽  
pp. 858-863 ◽  
Author(s):  
D. L. Stokes ◽  
N. R. MacIntyre ◽  
J. A. Nadel
Keyword(s):  
Carbon Monoxide ◽  
Oxygen Consumption ◽  
Healthy Subjects ◽  
Vital Capacity ◽  
Maximal Exercise ◽  
Sitting Position ◽  
Diffusing Capacity ◽  
Heavy Exercise ◽  
Lung Volumes ◽  
Rate Of Increase

To study the effects of exercise on pulmonary diffusing capacity, we measured the lungs' diffusing capacity for carbon monoxide (DLCO) during exhalation from 30 to 45% exhaled vital capacity in eight healthy subjects at rest and during exercise while both sitting and supine. We found that DLCO at these lung volumes in resting subjects was 26.3 +/- 3.2% (mean +/- SE) higher in the supine than in the sitting position (P less than 0.001). We also found that, in both positions, DLCO at these lung volumes increased significantly (P less than 0.001) with increasing exercise and approached similar values at maximal exercise. The pattern of increase in DLCO with an increase in oxygen consumption in both positions was curvilinear in that the rate of increase in DLCO during mild exercise was greater than the rate of increase in DLCO during heavy exercise (P = 0.02). Furthermore, in the supine position during exercise, it appeared that DLCO reached a physiological maximum.

scholarly journals Carbon Dioxide Capture Using a Zeolite Molecular Sieve Sampling System for Isotopic Studies (13C and 14C) of Respiration

Radiocarbon ◽  
2005 ◽  
Vol 47 (3) ◽  
pp. 441-451 ◽  
Author(s):  
S M L Hardie ◽  
M H Garnett ◽  
A E Fallick ◽  
A P Rowland ◽  
N J Ostle
Keyword(s):  
Mass Spectrometry ◽  
Molecular Sieve ◽  
Ecosystem Respiration ◽  
Isotope Ratio Mass Spectrometry ◽  
Gas Analyzer ◽  
Sampling System ◽  
Air Stream ◽  
Isotopic Studies ◽  
Isotope Studies ◽  
Infrared Gas Analyzer

A method for collecting an isotopically representative sample of CO2 from an air stream using a zeolite molecular sieve is described. A robust sampling system was designed and developed for use in the field that includes reusable molecular sieve cartridges, a lightweight pump, and a portable infrared gas analyzer (IRGA). The system was tested using international isotopic standards (13C and 14C). Results showed that CO2 could be trapped and recovered for both δ13C and 14C analysis by isotope ratio mass spectrometry (IRMS) and accelerator mass spectrometry (AMS), respectively, without any contamination, fractionation, or memory effect. The system was primarily designed for use in carbon isotope studies of ecosystem respiration, with potential for use in other applications that require CO2 collection from air.

Single-breath CO diffusing capacity influenced by initial alveolar partial pressure of CO

1998 ◽  
Vol 275 (1) ◽  
pp. R339-R342
Author(s):  
Hartmut Heller ◽  
Klaus-Dieter Schuster
Keyword(s):  
Mass Spectrometry ◽  
Partial Pressure ◽  
Breath Holding ◽  
Gas Mixture ◽  
Residual Volume ◽  
Diffusing Capacity ◽  
Time Intervals ◽  
Single Breath ◽  
Identical Manner ◽  
End Tidal

The purpose of this study was to assess the influence of incorrect determinations of the initial alveolar partial pressure of carbon monoxide (CO) at the beginning of breath holding (Pia CO) on the pulmonary CO diffusing capacity of the lung (Dl CO). Single-breath maneuvers were performed on 14 anesthetized and artificially ventilated rabbits, using 0.2% CO in nitrogen as the indicator gas mixture. Inflation and deflation procedures were carried out in an identical manner on each animal, with inflation always starting from residual volume. End-tidal partial pressure of CO was determined by respiratory mass spectrometry and was used to calculate Dl CO values with the application of the three-equation ( method 1), as well as the conventional ( method 2), solution. In each rabbit, method 2 caused Dl CO values to be overestimated when compared with method 1, and this overestimation decreased with increasing time intervals of CO uptake. Because we were able to recalculate this deviation using Pia COvalues that were obtained by taking the diffusive removal of CO during inflation into account, we concluded that errors in estimating Pia CO by applying method 2 significantly contribute to the discrepancy between both methods.

Competitive inhibition of carbon monoxide transport: evidence against a carrier

1981 ◽  
Vol 50 (5) ◽  
pp. 1061-1064 ◽  
Author(s):  
D. Z. Rubin ◽  
D. Fujino ◽  
C. Mittman ◽  
S. M. Lewis
Keyword(s):  
Carbon Monoxide ◽  
Competitive Inhibition ◽  
Normal Adult ◽  
Gas Mixture ◽  
Diffusing Capacity ◽  
Constant Amount ◽  
Pulmonary Diffusing Capacity ◽  
Co Concentration ◽  
Carrier Molecule ◽  
Co Concentrations

The existence of a saturable carbon monoxide (CO) carrier in the lung remains controversial. The carrier hypothesis was invoked to explain data that indicated that pulmonary diffusing capacity for CO (DLCO) decreases with increasing CO concentration. To test this hypothesis, we measured DLCO in 14 normal adult subjects at three alveolar CO concentrations (60, 660, and 2,060 ppm). Each mixture contained a constant amount of labeled C18O (60 ppm) and a balance of unlabeled C16O. If a saturable carrier exists at increasing CO concentrations, the unlabeled CO would compete for most of the sites on the carrier molecule, effectively inhibiting the uptake of the labeled C18O. C18O diffusing capacities (mean +/- SD) for the three levels of CO were 34.9 +/- 5.6, 33.0 +/- 6.0, and 34.7 +/- 7.8. There were no significant differences (P greater than 0.2) among the three levels. In another group of subjects we repeated the study using a gas mixture containing 130 ppm C18O. No significant differences were found. As a result, we find no evidence to support a CO carrier hypothesis.

Application to Woody Plants of a Rapid Method for Determining Leaf CO2 Compensation Concentrations

1973 ◽  
Vol 3 (2) ◽  
pp. 237-242 ◽  
Author(s):  
D. I. Dickmann ◽  
D. H. Gjerstad
Keyword(s):  
Rapid Method ◽  
Woody Plants ◽  
Woody Species ◽  
Moisture Stress ◽  
Gas Analysis ◽  
Deionized Water ◽  
Controlled Environment ◽  
Gas Analyzer ◽  
Leaf Ontogeny ◽  
Infrared Gas Analyzer

A rapid method of determining CO2 compensation concentrations was developed and applied to woody plants. Whole leaves, needle fascicles, and twigs were excised, the cut ends inserted in a vial of deionized water, and the assembly placed in a Mylar bag. The bag was filled with air containing ca. 400 p.p.m. CO2. After 1 h in a growth chamber (24 °C, 3800 ft-c (40 660 lux)), the air was expelled from the bag through an infrared gas analyzer. Compensation concentrations determined by this method agreed with values obtained by using conventional closed-circuit gas analysis. The method was successfully applied to 14 gymnosperm and 55 angiosperm woody species and clones, including field-grown plants and rooted cuttings grown under controlled environment. Variation among species was small, compensation concentrations usually falling between 55 and 65 p.p.m. CO2, the range associated with C3 plants. The influence of temperature, moisture stress, and leaf ontogeny on leaf CO2 compensation also was studied.

DlCO measurements with gas chromatography

1962 ◽  
Vol 17 (6) ◽  
pp. 856-860 ◽  
Author(s):  
Josef R. Smith ◽  
Lyle H. Hamilton
Keyword(s):  
Gas Chromatography ◽  
Normal Subjects ◽  
Inert Gas ◽  
Breath Holding ◽  
Gas Mixture ◽  
Diffusing Capacity ◽  
Gas Chromatograph ◽  
Excellent Correlation ◽  
Pulmonary Diffusing Capacity ◽  
The Mean

A gas chromatograph has been used to analyze gases for the measurement of pulmonary diffusing capacity using the breath-holding technique. The gas mixture used for the measurement consisted of carbon monoxide in air with neon as the insoluble inert gas. The calculated DlCO was unaffected when sulphur hexafloride (SF6) or He was substituted for Ne in the mixture, but since CO and Ne could be most simply and rapidly analyzed, this combination was preferred for the gas mixture used to measure DlCO. The mean DlCO for ten normal subjects was 25.8 ± 4.2 ml/min mm Hg. These results were comparable to values reported in the literature when established methods of analysis were used. An excellent correlation was found between calculated DlCO and the clinical condition of patients with impaired pulmonary diffusing capacity. Submitted on February 14, 1962

Nondispersive Infrared Gas Analyzer for Vapor Density Measurements of a Carbonyl-Containing Organometallic Cobalt Precursor

2017 ◽  
Vol 71 (12) ◽  
pp. 2632-2642 ◽  
Author(s):  
James E. Maslar ◽  
William A. Kimes ◽  
Brent A. Sperling ◽  
Ravindra K. Kanjolia
Keyword(s):  
Bandpass Filter ◽  
Sampling Rate ◽  
Signal Averaging ◽  
Gas Analyzer ◽  
Vapor Density ◽  
Flow Conditions ◽  
Ft Ir ◽  
Infrared Gas Analyzer ◽  
Ft Ir Spectroscopy

A nondispersive infrared (NDIR) gas analyzer was demonstrated for measuring the vapor-phase density of the carbonyl-containing organometallic cobalt precurso μ2-η2-(tBu-acetylene) dicobalthexacarbonyl (CCTBA). This sensor was based on direct absorption by CCTBA vapor in the C≡O stretching spectral region and utilized a stable, broadband IR filament source, an optical chopper to modulate the source, a bandpass filter for wavelength isolation, and an InSb detector. The optical system was calibrated by selecting a calibration factor to convert CCTBA absorbance to a partial pressure that, when used to calculate CCTBA flow rate and CCTBA mass removed from the ampoule, resulted in an optically determined mass that was nominally equal to a gravimetrically-determined mass. In situ Fourier transform infrared (FT-IR) spectroscopy was performed simultaneously with the NDIR gas analyzer measurements under selected conditions in order to characterize potential spectroscopic interferences. Interference due to CO evolution from CCTBA was found to be small under the flow conditions employed here. A CCTBA minimum detectable molecular density as low as ≈3 × 1013 cm−3 was calculated (with no signal averaging and for a sampling rate of 200 Hz). While this NDIR gas analyzer was specifically tested for CCTBA, it is suitable for characterizing the vapor delivery of a range of carbonyl-containing precursors.

TROCAS GASOSAS EM PLANTAS DE CANA-DE-AÇÚCAR INOCULADAS COM GLUCONACETOBACTER DIAZOTROPHICUS E SUBMETIDAS AOS ESTRESSES SALINO E HÍDRICO

2020 ◽  
Vol 03 (01) ◽  
pp. 57-63
Author(s):  
Janice Dias ◽  
Keyword(s):  
Abiotic Stress ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Endophytic Bacteria ◽  
Gluconacetobacter Diazotrophicus ◽  
Gas Analyzer ◽  
Sugarcane Crop ◽  
Lower Productivity ◽  
High Doses ◽  
Infrared Gas Analyzer

The sugarcane crop isconsidered moderately sensitive to environmental stresses, which results in reduced growth and lower productivity. In addition, there is a need for the application of high doses of nitrogen fertilizer. A potential and agroecologically correct alternative is the use of nitrogen-fixing endophytic bacteria, such as Gluconacetobacter diazotrophicus. However, under conditions of abiotic stress the benefits from this plant-endophyte association can be altered due to the physiology of stress response. The objective of this work was to study the effect of inoculation of G. diazotrophicus by means of the evaluation of the parameters of gas exchange, in sugarcane plants submitted to salt and water stresses. The rates of stomatal conductance, transpiration and liquid photosynthesis were evaluated by means of a portable infrared gas analyzer (IRGA). The results showed that the presence of the bacteria may alter the rates of stomatal conductance and transpiration, interfering in the physiology of response to salinity and drought. Keywords: Endophytic bactéria. Stomatal conductance. Transpiration. Salinity. Drought.

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