scholarly journals Scale and stability of methane standard gas in JMA and comparison with MRI standard gas

2016 ◽  
Vol 66 (0) ◽  
pp. 15-24 ◽  
Author(s):  
Kazuhiro TSUBOI ◽  
Hidekazu MATSUEDA ◽  
Yousuke SAWA ◽  
Yosuke NIWA ◽  
Masaomi TAKAHASHI ◽  
...  
Keyword(s):  
Standard Gas

Evaluation of two alternative ablation treatments for cervical pre-cancer against standard gas-based cryotherapy: a randomized non-inferiority study

2019 ◽  
Vol 29 (5) ◽  
pp. 851-856 ◽  
Author(s):  
Miriam Cremer ◽  
Karla Alfaro ◽  
Jillian Garai ◽  
Manuel Salinas ◽  
Mauricio Maza ◽  
...  
Keyword(s):  
Low Income ◽  
Histological Evaluation ◽  
Cervical Tissue ◽  
Post Surgery ◽  
Pain Scores ◽  
Patient Pain ◽  
The Difference ◽  
Cure Rates ◽  
Treatment Application ◽  
Standard Gas

IntroductionGas-based cryotherapy is the conventional ablative treatment for cervical pre-cancer in low-income settings, but the use of gas poses significant challenges. We compared the depth of necrosis induced by gas-based cryotherapy with two gas-free alternatives: cryotherapy using CryoPen,and thermoablation.MethodsWe conducted a five-arm randomized non-inferiority trial: double-freeze carbon dioxide (CO2) cryotherapy (referent), single-freeze CO2 cryotherapy, double-freeze CryoPen, single-freeze CryoPen, and thermoablation. Subjects were 130 women scheduled for hysterectomy for indications other than cervical pathology, and thus with healthy cervical tissue available for histological evaluation of depth of necrosis post-surgery. The null hypothesis was rejected (ie, conclude non-inferiority) if the upper bound of the 90% confidence interval (90% CI) for the difference in mean depth of necrosis (referent minus each experimental method) was <1.14 mm. Patient pain during treatment was reported on a scale of 0 (no pain) to 10 (worst pain).ResultsA total of 133 patients were enrolled in the study. The slides from three women were deemed unreadable. One patient was excluded because her hysterectomy was postponed for reasons unrelated to the study, and two patients were excluded because treatment application did not follow the established protocol. For the remaining 127 women, mean depth of necrosis for double-freeze CO2 (referent) was 6.0±1.6 mm. Differences between this and other methods were: single-freeze CO2 = 0.4 mm (90% CI −0.4 to 1.2 mm), double-freeze CryoPen= 0.7 mm (90% CI 0.04 to 1.4 mm), single-freeze CryoPen= 0.5 mm (90% CI −0.2 to 1.2 mm), and thermoablation = 2.6 mm (90% CI 2.0 to 3.1 mm). Mean pain levels were 2.2±1.0 (double-freeze CO2 cryotherapy), 1.8±0.8 (single-freeze CO2 cryotherapy), 2.5±1.4 (double-freeze CryoPen), 2.6±1.4 (single-freeze CryoPen), and 4.1±2.3 (thermoablation).DiscussionCompared with the referent, non-inferiority could not be concluded for other methods. Mean pain scores were low for all treatments. Depth of necrosis is a surrogate for treatment efficacy, but a randomized clinical trial is necessary to establish true cure rates.

The preparation of standard gas mixtures. A review

The Analyst ◽  
1981 ◽  
Vol 106 (1265) ◽  
pp. 817 ◽  
Author(s):  
R. S. Barratt
Keyword(s):  
Gas Mixtures ◽  
Standard Gas Mixtures ◽  
Standard Gas

scholarly journals The Determination of Nitric Oxide in Gas Phase Cigarette Smoke by Non-dispersive Infrared Analysis

1980 ◽  
Vol 10 (2) ◽  
Author(s):  
T. B. Williams
Keyword(s):  
Nitric Oxide ◽  
Gas Phase ◽  
Cigarette Smoke ◽  
Relative Error ◽  
Dead Volume ◽  
High Yield ◽  
Infrared Analysis ◽  
Colorimetric Analysis ◽  
Standard Gas

AbstractNitric oxide in cigarette smoke was conveniently determined by non-dispersive infrared analysis (NDIR). Recoveries of 95 % were obtained with standard gas-air mixtures but recoveries from smoke increased from 87% for high-yield to 91 % for low-yield cigarettes. Relative error was about 4 %. A reduction in the dead volume of Cambridge filter cassettes, to reduce the amount of NO reacted between puffs, increased NO deliveries of cigarettes by 4%. Deliveries of NO were estimated to average 4 % lower due to oxidation, but reaction with other smoke components reduced them further depending upon concentrations. The NO deliveries of cigarettes increased as blend nitrate increased and as the flow of air around cigarettes decreased. Nitric oxide in smoke and in standard gas-air mixtures, determined by non-dispersive infrared (NDIR) spectroscopy, was substantiated by an automated colorimetric analysis. Interfering smoke species were determined and circumvented in both methods.

Application of standard gas validation and supporting vector machine in spectral fidelity improvement

2019 ◽  
Vol 27 (10) ◽  
pp. 2144-2153
Author(s):  
季文海 JI Wen-hai ◽  
宋 迪 SONG Di ◽  
吕晓翠 L Xiao-cui ◽  
李国林 LI Guo-lin
Keyword(s):  
Spectral Fidelity ◽  
Standard Gas

Assay of NF Ethylene by Gas Chromatography

1972 ◽  
Vol 55 (5) ◽  
pp. 1067-1069
Author(s):  
N Aubrey Carson
Keyword(s):  
Atmospheric Pressure ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Thermal Conductivity Detector ◽  
Gas Chromatograph ◽  
Gas Sampling ◽  
Gas Chromatographic Method ◽  
Standard Gas

Abstract A gas chromatographic method, utilizing a 6′ × 1/4″ Poropak R column and a thermal conductivity detector, was developed for the analysis of NF ethylene. The sample was introduced into the gas chromatograph at atmospheric pressure, using a gas sampling valve with calibrated loop. A high purity standard gas was used for comparison. With the instrument set for optimum operating conditions the precision for multiple injections of standard gas was excellent. The assay value of a sample was found to be 99.7%, when determined on 3 separate days. A collaborative study of the method is recommended.

scholarly journals H<sub>2</sub>S interference on CO<sub>2</sub> isotopic measurements using a Picarro G1101-i cavity ring-down spectrometer

2015 ◽  
Vol 8 (10) ◽  
pp. 4075-4082 ◽  
Author(s):  
K. Malowany ◽  
J. Stix ◽  
A. Van Pelt ◽  
G. Lucic
Keyword(s):  
Hydrogen Sulfide ◽  
Field Trials ◽  
Spectral Lines ◽  
Robust Method ◽  
Controlled Experiments ◽  
Δ13c Value ◽  
Future Work ◽  
Isotopic Measurements ◽  
Standard Gas ◽  
Cavity Ring Down

Abstract. Cavity ring-down spectrometers (CRDSs) have the capacity to make isotopic measurements of CO2 where concentrations range from atmospheric (~ 400 ppm) to 6000 ppm. Following field trials, it has come to light that the spectrographic lines used for CO2 have an interference with elevated (higher than ambient) amounts of hydrogen sulfide (H2S), which causes significant depletions in the δ13C measurement by the CRDSs. In order to deploy this instrument in environments with elevated H2S concentrations (i.e., active volcanoes), we require a robust method for eliminating this interference. Controlled experiments using a Picarro G1101-i optical spectrometer were done to characterize the H2S interference at varying CO2 and H2S concentrations. The addition of H2S to a CO2 standard gas reveals an increase in the 12CO2 concentration and a more significant decrease in the 13CO2 concentration, resulting in a depleted δ13C value. Reacting gas samples containing H2S with copper prior to analysis can eliminate this effect. Models post-dating the G1101-i carbon isotope analyzer have maintained the same spectral lines for CO2 and are likely to have a similar H2S response at elevated H2S concentrations. It is important for future work with CRDS, particularly in volcanic regions where H2S is abundant, to be aware of the H2S interference on the CO2 spectroscopic lines and to remove all H2S prior to analysis. We suggest employing a scrub composed of copper to remove H2S from all gas samples that have concentrations in excess of 1 ppb.

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