Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “GASES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,135 records · Page 63Linked to original sources
PubMed2006

[Effects of urea and coated urea on harmful gases concentrations in plastic greenhouse].

With simulation test and plastic greenhouse experiment, this paper studied the effects of urea and minerals- coated urea on the soil pH and harmful gases concentrations in plastic greenhouse. The results showed that under simulated condition, the application of these'two N fertilizers led to an initial increase of soil pH, which reached the maximum (an increment of > 50%) within the first week and dropped to the initial level by the end of the fifth week. In plastic greenhouse, applying urea and coated urea resulted in the increase of NH3, NO2 and O3 concentrations. The daily volatilization amount of NH3 and NO2 was higher in urea treatment than in coated urea treatment, and the highest value in urea treatment was 42.36 microg x m(-3) x d(-1) for NH3, 41.95 microg x m(-3) x d(-1) for NO2, and 86.00 microg x m(-3) x d(-1) for O3. The volatilization intensity of NH3 and NO2 was influenced by temperature and sunlight, while the O3 concentration was influenced by sunlight.

Ammonia↗
PubMed2006

[Fast algorithm for feature extraction and identification of infrared spectra of polluted gases].

With the multi-resolution analysis, features of infrared spectra of polluted gases were extracted. Then the data were trained or identified by a neural network system. The experimental results show that the combination of the wavelet transform and the neural network has the great ability of feature extracting. And the system is quite efficient for identifying infrared spectra.

English Abstract↗
PubMedDate not supplied

[Conditions for the development of isobaric counterdiffusion of inert gases and the criteria of its evaluation].

Investigation of superficial counterdiffusion of nitrogen against helium has been carried out to evaluate a possibility of its progress in divers (107 tests) under pressures equivalent to 32-450 m of sea water when breathing trimix being saturated in heliox at a constant ambient pressure without changing chamber environment. Breathing gas mixture contained 248-800 kPa of nitrogen, while chamber heliox media contained some additions of nitrogen (6-108 kPa). Clinical manifestations of breathing trimix (itching and gas bubble formation) were studied in divers. The development of counterdiffusion depends on the partial pressure of nitrogen not only in the breathing gas mixture but also in the chamber media. The breathing nitrogen level being increased and (or) decreased in the chamber media, the counterdiffusion symptoms grow relative to the number (%) of cases. Minimal critical values of nitrogen partial pressure gradients in the mixture which induce counterdiffusion skin lesions are 260-320 kPa on the average for the nitrogen concentration in the chamber mixture to 30 kPa. Isobaric supersaturation due to inert gases countertransport in body tissues as a result of gas-switching from heliox to trimix is responsible for the syndrome development.

Administration, Inhalation↗
PubMed1991

Collateral ventilation by diffusion across the alveolar walls and the exchange of inert gases in the lung.

The underlying hypothesis of this study is that collateral ventilation by diffusion of occluded air spaces in the lungs of patients with chronic obstructive pulmonary disease (COPD) may play a substantial role in the pulmonary gas exchange of these patients. Using a related lung model we have simulated: a) the multiple-breath washout of helium (He) and sulphur hexafluoride (SF6) from the alveolar space, and b) the washout of inert tracer gases with different blood-gas partition coefficients, range 0.01-330, from mixed venous blood. These computations were carried out for different values of the collateral diffusion capacity (CDC). Next, the results obtained at each individual value of CDC were used to compute the breath number (NCR) at the crossing-over of the He-SF6 washout curves and the inert gas shunt fraction QS/QC. NCR and QS/QC range up to about 100 and 0.04, respectively, when CDCSF6 ranges down to about 0.1 ml.min-1.mmHg-1. These ranges for NCR and QS/QC, and the typical finding of relatively large values for NCR in combination with small values for QS/QC, are also reported in the literature for patients with COPD. These agreements thus support our hypothesis. In line with the small values for QS/QC, our results further indicate that even large, well-perfused, occluded air spaces in the lung will hardly affect the recovered ventilation/perfusion distribution obtained from inert gas data when CDCSF6 exceeds 0.1 ml.min-1.mmHg-1.

Computer Simulation↗
PubMed1975

Normal arterial blood gases during experimental hypertriglyceridemia in the rat.

The possible effect of high concentrations of plasma triglycerides on arterial oxygen tension was investigated in rats by infusion of lymph chylomicrons or a soybean oil emulsion (Intralipid). Mean triglyceride concentrations were raised from 130 to 1454 mg/100 ml without statistically significant change in arterial oxygen tension, oxygen saturation, carbon dioxide tension, or pH. The small reduction in arterial oxygen tension, content, or saturation observed in earlier studies may have been due to inadequate stabilization of fat emulsion then available for intravenous use. The present data suggest that high concentrations of plasma triglycerides produced by infusion of chylomicrons or Intralipid do not affect arterial blood gases in the normal rat.

Animals↗
PubMed1991

Respiratory gases and acid base parameter of the fetus during the second and third trimester.

Respiratory gases and acid base parameters were determined in the samples of fetal blood collected by cordocentesis from 70 patients with normal course of pregnancy, between 18th and 38th gestational week. The mean pH value was 7.386 +/- 0.05; partial pCO2 pressure -4.819 +/- 1.464 kPa; O2-5.712 +/- 1.24 kPa; bicarbonate 21.528 +/- 0.494 mMol/l; base excess -2.284 +/- 0.647 mMol/l and saturation 74.86 +/- 13%. Statistically significant negative correlation between gestational age and pH (r = 0.841, p less than 0.01) and partial O2 pressure (r = -0.961, p less than 0.01) was revealed. Partial CO2 pressure correlated significantly with gestational age (r = 0.923, p less than 0.01). The values of bicarbonate and base excess do not change significantly during gestation. Our own standards of examined parameters were formed.

Acid-Base Equilibrium↗
PubMed1991

The influence of anemia on respiratory gases and acid base parameters of the fetus.

Fetal blood samples were collected by cordocentesis from 82 pregnant women; 12 of whom had severe forms of Rh isoimmunization, while 70 comprised the control group. The mean hematocrit value in the group under investigation was 15.72 +/- 3.62% and indication of severe anemia. The pH value in this group was 7.31 +/- 0.06; pCO2 partial pressure 6.36 +/- 0.64; O2-2.65 +/- 0.89 kPa; bicarbonate 23.84 +/- 3.02 mMol/l: base excess was -2.72 +/- 2.66 mMol/l and saturation 28.66 +/- 15.56%. In the control group the following values were established: pH -7.386 +/- 0.05; partial pressure pCO2-4.980 +/- 0.31 kPa; O2--4.960 +/- 0.90 kPa; bicarbonate 21.560 +/- 0.27 mMol/l; base excess -2.30 +/- 0.90 mMol/l and saturation 67.23 +/- 11.60%. The pH, partial pressure O2 and saturation values were significantly lower, while partial pressure CO2 was significantly higher in the investigated group than in the control group. Bicarbonates and base excess do not change significantly in the presence of anemia. Fetal blood sampling carried out by means of cordocentesis is the most reliable method for assessment of the degree of fetal anemia. The values of acid base parameters and of blood gases are an indication of either respiratory, respiratory-metabolic or metabolic acidosis. The possibilities of prenatal diagnostics, undoubtedly, contribute to a significant reduction of perinatal mortality.

Acid-Base Imbalance↗
PubMedDate not supplied

Differential responses of canine myosin ATPase activity and tissue gases in the pressure-overloaded ventricle dependent upon degree of obstruction: mild versus severe pulmonic and aortic stenosis.

Mild pulmonic stenosis, induced in dogs by banding the pulmonary artery, elevated right ventricular peak systolic pressure to 60% above the control and elevated right ventricular K+- and Ca2+- activated myosin ATPase activities. In contrast, severe pulmonic stenosis, which elevated right ventricular peak systolic pressure to 300% above the control, did not produce an increase in myosin enzymatic ATPase Vmax values but caused a decrease in myosin activity. Mild aortic stenosis, induced by banding the ascending aorta, forcing a transaortic pressure gradient of 25 mm Hg, caused an elevation in left ventricular muosin ATPase, whereas severe aortic banding, brought about by creating a transaortic pressure gradient of 55 mm Hg, never caused an elevation in left ventricular myosin enzymatic Vmax values, but, like severe pulmonic banding, caused a decrease in K+- and Ca2+- activated myosin activities. Normal left ventricular myosin Vmax values in mumol of PO4/mg-min at 37 degrees C were: K+ = 2.84 +/- 0.22, and Ca2+ = 0.97 +/- 0.14. For right ventricular myosin they were: K+ = 2.15 +/- 0.16, and Ca2+ =0.74 +/- 0.10. Analyses of tissue gases, based on mass spectrometry data, showed that the hypertrophied ventricles had an elevated tissue pCO2 and an elevation in the cGMP/cAMP ratio.

Adenosine Triphosphatases↗
PubMed1990

[Electrocardiography and arterial blood gases monitoring during fiberoptic bronchoscopy].

Electrocardiography (ECG) and arterial blood gases (ABG) were taken to monitor 90 patients prior to, during and after bronchofiberscopy. PaO2 generally decreased during the procedure without supplemental oxygen. Patients who underwent bronchofiberscopy with PaO2 less then 9.31 kPa were 66.67%. The mean of the decrease of SaO2 was 5.79 +/- 7.74%. 83.33% of the patients developed sinus tachycardia. There were 26.67% of the patients showed abnormal P wave, ST-T wave, Q-T interval etc during the procedure. 93.33% of them were given oxygen via a nasal stuff during the procedure and had an increase of PaO2.

Adult↗
PubMed1990

[Monitoring of myocardial gases and evaluation of the viability of the preserved heart].

For the evaluation of the viability of a nonfunctioning stored heart, a system of myocardial gases (pO2, pCO2) monitoring was developed and approved . It is shown that myocardial pCO2 monitoring is most informative in evaluation of viability of a stored heart. The character of this curve makes it possible to identify the duration of storage admissible in each concrete case as well as the loss of viability by the heart.

Animals↗
PubMed1990

[Effect of induced hypotension on arterial blood-gases].

Arterial blood-gases were evaluated before, during and after the vasodilator induced hypotension in patients undergoing mastectomy. Forty-two patients studied were anesthetized with halothane and nitrous oxide in oxygen. They were divided into following four groups according to vasodilators used: trimetaphan (TMP), nitroglycerin (TNG), adenosine triphosphate (ATP), and prostaglandin E1 (PGE1). Significant reduction in PaO2 was observed during induced hypotension in all groups. However, there was no difference in the degree of PaO2 decrease among four groups. A small but significant increase in PaCO2 and a decrease in pH were observed during and/or after hypotension with TNG and PGE1. These findings suggest that induced hypotension may impair the pulmonary gas exchange by decreased cardiac output and/or change in ventilation-perfusion ratio regardless of vasodilators used. Therefore, continuous arterial blood-gas monitoring should be desirable under these conditions.

Adenosine Triphosphate↗
PubMed1990

[Hygienic and health problems related to the use of anesthetic gases and vapors].

The risk of pollution by anesthetic gases in operating rooms is examined and the pathologies that can affect exposed personnel are analyzed. As to prevention, measures for ensuring safety of devices used in operating rooms are indicated, as well as procedures for monitoring environment and personnel.

Air Pollutants, Occupational↗
PubMed1990

Monitoring of blood gases during extracorporeal circulation with an artificial lung.

During cardiopulmonary bypass, the heart-lung machine and the patient's gas exchange systems (uptake and elimination) form an undissociable couple. Changes in one of the components lead to corresponding changes in the other. In the artificial lung, like in the natural lung and peripheral tissues, gas exchanges depend on several parameters: blood inlet conditions, blood flow rate, temperature, composition of the gas mixture used for ventilation, blood tissue perfusion, O2 consumption, etc. The perfusionist's primary objective is to obtain from the artificial lung adequate O2 delivery to and CO2 removal from the tissues. This paper discusses the main parameters which must be taken into account and analyses the main sensors currently available for in-line measurement of blood gases.

Blood Gas Analysis↗
PubMed1990

Arterial blood gases: clinical application.

The interpretation of arterial blood gases (ABGs) is an essential assessment skill for the PACU nurse. ABG analysis can be fun and exciting, as well as an important tool for patient care. Acid-base imbalances are associated with various clinical conditions. Using ABGs as an assessment tool, the PACU nurse can determine the patient's acid-base status and initiate prompt, appropriate nursing intervention and medical consultation.

Acid-Base Imbalance↗
PubMed1975

Analysis of gases and pH of blood at altitude.

The accuracy of a system for measuring pH and gas in blood in a changing-altitude environment was studied. No problems were encountered when arterial blood was measured, provided the instrument was properly calibrated. Failure to calibrate to the correct altitude settings caused major variations in measuring oxygen levels in blood. Standard gases used for calibrating were measured at altitude without recalibrating the system; approximately 80% of the oxygen and 90% of the carbon dioxide partial-pressure values were within 3 mm Hg of their expected value. More deviation occurred for Po2 values as the altitude increased. Frequently, the Po2 electrode malfunctioned, particularly above 8000 ft (2438 m). The Corning Blood Gas System, which was used in this study, was capable of making accurate determinations of gas in blood if properly operated and calibrated to specific altitude levels.

Altitude↗
PubMed1986

Consumption of pentane by hepatic microsomes and consequences on pentane measurement in exhaled gases.

Pentane measurement in exhaled gases was proposed as a safe method to evaluate the importance of lipoperoxidation in vivo, in man and in animals. However we have observed that pentane, which arises from lipoperoxide decomposition, is significantly consumed by cytochrome P-450-rich liver microsomes. This pentane consumption is completely inhibited after heating the microsomes at 100 degrees C, and is considerably reduced by metyrapone, a cytochrome P-450 inhibitor. Hepatic metabolism of pentane, particularly after cytochrome P-450 induction, constitutes a risk of error, when pentane exhalation is taken as an index of lipoperoxidation in vivo.

Animals↗
PubMed1989

[Effect of hemodilution with 10% hydroxyethyl starch solution (MW 200,000/9.5) on the flow properties of blood, arterial blood gases and conjunctival oxygen partial pressure in patients with cerebral infarct].

Hemorheological parameters, arterial blood gases and conjunctival oxygen tension were measured in 15 patients with acute ischemic stroke and compared with values obtained in an age matched reference group. Since the conjunctival capillary bed is perfused by the ophthalmic artery, it reflects the oxygen delivery to the areas supplied by the internal carotid artery. Measurements of conjunctival oxygen tension are simple and safe. Patients with acute ischemic stroke showed a lowered conjunctival oxygen tension; this holds true especially to the ipsilateral side, i.e. the side where the attack occurred, and to a lesser extent to the other side. By contrast, the ratio of arterial/conjunctival pO2 was disturbed only on the ipsilateral side. Furthermore, these patients had pathologically elevated values for red cell aggregation, whole blood and plasma viscosity. After infusing 500 ml 10% middle-molecular-weight hydroxyethyl starch (10% HAES-steril) and phlebotomy (250 ml) blood fluidity was normalized, although the hematokrit was only slightly reduced. Arterial pO2 improved slightly while pCO2 remained unchanged. Conjunctival oxygen tension improved by 30% on the ipsilateral and by 10% on the contralateral side, the ipsilateral values always remaining significantly lower. The ratio conjunctival/arterial pO2 raised only on the ipsilateral side where it was below the reference range before hemodilution. In addition to the well known improvement of blood fluidity and augmentation of cerebral blood flow following hemodilution in patients with acute ischemic stroke, there seems to be an increase in oxygen supply in the territories of both internal carotid arteries, especially on the ipsilateral side as indicated by the values of conjunctival oxygen tension and the ratio of conjunctival to arterial pO2.

Blood Viscosity↗