The denitrifier method is widely used as a novel pretreatment method for the determination of nitrogen and oxygen isotope ratios as it can provide quantitative and high-sensitivity measurements. Nevertheless, the method is limited by relatively low measurement accuracy for δ18O. In this study, we analyzed the factors influencing the accuracy of δ18O determination, and then systematically investigated the effects of dissolved oxygen concentrations and nitrate sample sizes on estimates of the δ15N and δ18O of nitrate reference materials. The δ18O contraction ratio was used to represent the relationship between the measured difference and true difference between two reference materials. We obtained the following main results: (1) a gas-liquid ratio of 3:10 (v/v) in ordinary triangular flasks and a shaking speed of 120 r/min produced an optimal range (1.9 to 2.6 mg/L) in the concentration of dissolved oxygen for accurately determining δ18O, and (2) the δ18O contraction ratio decreased as nitrate sample size decreased within a certain range (1.0 to 0.1 μmol). Our results suggested that δ18O contraction is influenced mainly by dissolved oxygen concentrations in pure culture, and provided a model for improving the accuracy of oxygen isotope analysis.
Denitrification ; Nitrates/analysis* ; Oxygen Isotopes/analysis*

This article describes the design of a portable blood oxygen simulation system that can be used to simulate various blood gas saturation states of the human body. The system can be used to simulate various states of blood gas saturation, and can also simulate large blood oxygen saturation dynamic range, pulse rate range and perfusion index range. It can be used for testing, but not for clinical examination instruments. Moreover, the system has the characteristics of small size and low cost compared with the commercial blood oxygen simulator. Although the simulation system is not directly used for the detection of blood gas saturation of patients, it is also an essential equipment in the production and testing process, so it has certain practical value.
Heart Rate ; Humans ; Oximetry ; instrumentation ; Oxygen ; analysis

The stochastic profile of variability of biochemical oxygen demand (BOD) and dissolved oxygen (D0) in the Han River has been considered with Streeter-Phelp's equation. According to the nature of the Han River, the BOD removal coefficient, K1, and the reaeration coefficient, K2 values, were calculated at an average of 0.157 and 0.97 respectively at 20 degrees C in the spring. Where the levels of BOD would be high in relation to the standard of water quality, the treatment for sewage and industrial wastes from tributaries of Seoul City should be performed with proper efficiency. Before 1985 plants with 90% efficiency should be installed at every outlet of the tributaries. The level of DO is not a relevant parameter to assess the pollution in the Han River. The description of the oxygen profile of the Han River also suggests monitoring points for inspection of water quality.
Fresh Water/analysis* ; Korea ; Models, Chemical ; Oxygen/analysis* ; Water/analysis* ; Water Pollution, Chemical/analysis

PURPOSE: To determine whether seminal malondialdehyde and carbonyl group have any relation to sperm motility. MATERIALS AND METHODS: Human semen samples were obtained by masturbation after 3 days of abstinence from patients consulting an infertility clinic. Using conventional semen analysis, samples were divided into two groups according to sperm motility (group 1: motility > OR =50%, group 2: motility <50%). Malondialdehyde and carbonyl group were measured in whole semen. RESULTS: The amount of malondialdehyde and carbonyl group was slightly lower in group 1 than group 2. CONCLUSIONS: Although the difference between the groups was not statistically significant, it seems possible that malondialdehyde and carbonyl group, which are produced from reactive oxygen, are negatively correlated with sperm motility.
Humans* ; Infertility ; Malondialdehyde ; Masturbation ; Oxygen ; Reactive Oxygen Species* ; Semen ; Semen Analysis ; Sperm Motility ; Spermatozoa*

This study was conducted to investigate of water qualities in the upper and middle reaches of the Han River. For this purpose, water was sampled at Kwangjin and 1st Han-River Bridges of the Han River in Seoul and analysed from August, 1988 to September, 1989. The results are summarized as follows: 1. Water quality at 1st Han-River Bridge was more polluted than that at Kwangjin Bridge. 2. Except biological oxygen demand (BOD), turbidity, suspended solid (SS), dissolved oxygen (DO), DO saturation (DOS), ammonia nitrogen (NH3-N), nitrite nitrogen (NO2-N) and chloride ion (Cl-) at Kwangjin and 1st Han-River Bridges were lower as compared with the previous data before redevelopment of the Han River. 3. SS, DO and pH at Kwangjin and 1st Han-River Bridges could be classified to the 1st grade in environmental water quality standard. DOS at Kwangjin Bridge was over 100% and that at 1st Han-River Bridge was below 100% in the Han River. BOD at Kwangjin Bridge could be classified to 2nd grade and that at 1st Han-River Bridge to 3rd grade in environmental water quality standard. 4. The higher the level of water was, the lower the levels of turbidity and SS, and NH3-N was decreased with increasing water level at 1st Han-River Bridge. DO was decreased as water temperature went up but DOS was increased with DO. BOD was positively correlated with nitrite-nitrogens. 5. Turbidity and SS at the both sites and Chloride ion (Cl-) at Kwangjin Bridge were increased in July and August. And DO at the both sites and NH3-N at 1st Han-River Bridge were decreased in at July and August.
Ammonia ; Biological Oxygen Demand Analysis ; Hydrogen-Ion Concentration ; Nitrogen ; Oxygen ; Rivers ; Seasons* ; Seoul ; Water Quality ; Water*

To observe the relationship between oxygen consumption and body temperature during cardiopulmonary bypass, the authors checked nasopharyngeal and rectal temperature, hemoglobin, and arterial and venous blood gas analysis. At the time when nasopharyngeal and rectal temperatures were equal, it was shown that oxygen consumption had a good relationship (r=0.78) with body temperature. From this data it was revealed that oxygen consumption decreased with decreasing temperature at the rate of about 0.16 ml/kg/min/C.
Blood Gas Analysis ; Body Temperature* ; Cardiopulmonary Bypass ; Extracorporeal Circulation* ; Oxygen Consumption* ; Oxygen*

Oxygen reserve index (ORI) is a novel dimensionless index used for noninvasive, real-time, and continuous monitoring of oxygenation, and ORI value ranges from 0 to 1, which reflects the range of 100-200 mmHg for arterial partial pressure of oxygen. ORI combined with pulse oximetry may help to accurately adjust the concentration of inspired oxygen and prevent hyperoxemia and hypoxemia. ORI is suitable for various clinical situations, and the medical staff should master this novel parameter and use it properly to assess the oxygenation of patients. In addition, several limitations of ORI should be noticed during clinical application.
Humans ; Oxygen ; Blood Gas Analysis ; Oxygen Inhalation Therapy ; Oximetry ; Hypoxia/therapy*

OBJECTIVE: To verify the accuracy of oxygen concentration (FiO₂) of modified oxygen treatment with Venturi and humidity system. METHODS: Patients just after ventilator weaning and before the removal of tracheal intubation/tracheotomy tube, who admitted to the intensive care unit (ICU) of Henan Provincial People's Hospital from May 1st to December 15th in 2017, were enrolled. All patients were given a modified oxygen treatment with Venturi and humidity system, and the oxygen flow rate (Flow) of the Venturi device and the oretical value of FiO₂ were adjusted according to the patient's condition. Patients were divided into five groups based on doctor's orders: Flow 3 L/min FiO₂ 0.24, Flow 3 L/min FiO₂ 0.26, Flow 6 L/min FiO₂ 0.28, Flow 6 L/min FiO₂ 0.30, Flow 9 L/min FiO₂ 0.35. The value of FiO₂ at the inhalation end of patients of each group was measured by TSI airflow analyzer, and the consistency between the measured value of FiO₂ at the inhalation end and the FiO₂ marked value of Venturi was compared and analyzed. RESULTS: When the FiO₂ theoretical value of Venturi were adjusted to 0.24, 0.26, 0.28, 0.30, and 0.35, the measured values of FiO₂ at the inhalation end of patients were 0.38±0.05, 0.38±0.05, 0.40±0.04, 0.41±0.04, and 0.77±0.11, respectively, which were all significantly higher than the theoretical value of FiO₂ (all P < 0.01). The difference between the measured value of FiO₂ at the inhalation side and the FiO₂ value of the Venturi annotated and the difference rate were both "V"-shaped, both of which decreased with the increase in theoretical value of FiO₂ to a Flow of 9 L/min and a theoretical value of FiO₂ 0.35, the accuracy was the worst, with the FiO₂ difference of 0.42±0.11, and the FiO₂ difference rate of (121.6±36.5)%. CONCLUSIONS There is a difference between the measured value and the theoretical value of FiO₂ at the inhalation end of the modified Venturi oxygen therapy humidification system, which needs to be paid attention to during clinical oxygen therapy.
Humans ; Humidity ; Oxygen/analysis* ; Oxygen Inhalation Therapy ; Respiration, Artificial ; Ventilator Weaning

A develop of medical discharger of oxygen is presented in the paper. The medical discharge can control, display and print the output data including the time, oxygen discharge the total time and the total oxygen discharge of two channels oxygen synchronously or respectively, Results show that the device is of reasonable design, accurate, measurement simple operation, low cost, real-time display, alarm and controlling the channels oxygen automatically and can print data if necessary. It will be widely used in clinic.
Data Display ; Equipment Design ; Humans ; Oxygen ; analysis ; Oxygen Inhalation Therapy ; instrumentation ; Weights and Measures ; instrumentation

Determined the easily oxidized substance of the injector based on GB15810-2001, and analyzed the source of uncertainty of the process of titration symmetrically, and valued the uncertainty of the result of data analysis.
Oxidation-Reduction ; Oxygen Compounds ; analysis ; Syringes ; Titrimetry ; Uncertainty