In order to investigate the oxidation kinetics of gas coal at low temperatures, we derived a rate equation of oxygen consumption during low-temperature oxidation of gas coal and deduced an E-c equation, expressing the...In order to investigate the oxidation kinetics of gas coal at low temperatures, we derived a rate equation of oxygen consumption during low-temperature oxidation of gas coal and deduced an E-c equation, expressing the relation between active energy E and oxygen concentration c. The reaction order n and active energy E were calculated with this equation based on experiments of static oxygen consumption tests. In addition, we proved the rationality of the E-c equation using a kinetic compensation effect and obtained the isokinetic temperature Tc. The results show that： 1） the gas coal oxidizes easily with increasing temperature and the oxidation tends to be spontaneous at higher temperatures; 2） the oxygen concentration c affects oxygen consumption very much at lower temperatures but has only a small effect at higher temperatures; 3） the isokinetic temperature Tc was 127 ℃ which has been experimentally validated as the key turning point during low-temperature spontaneous combustion of gas coal.展开更多
Background There is no research,either at home or abroad,focusing on assessing the cardiopulmonary functional reserve and exercise tolerance in patients with pulmonary embolism （PE）,but the benefits of early exercis...Background There is no research,either at home or abroad,focusing on assessing the cardiopulmonary functional reserve and exercise tolerance in patients with pulmonary embolism （PE）,but the benefits of early exercise are well recognized.The goals of this study were to assess cardiopulmonary functional reserve in treated PE patients using the inert gas rebreathing method of the cardiopulmonary exercise test （CPET）,and to compare it with traditional methods.Methods CPET on the bicycle ergometer were performed in 40 patients with age,gender,body mass index,systolic blood pressure,and pulmonary function matched.The first group was the PE group composed of 16 PE patients （5 male,11 female） who were given the standard antithrombotic therapy for two weeks.The second group was composed of 24 normal individuals （10 male,14 female）.Both groups were evaluated by cardiac ultrasound examination,6-minute walking test （6MVVT）,and CPET.Results （1） Right ventricular systolic pressure （RVSP） in the PE group increased significantly compared to the control group,（34.81±8.15） mmHg to （19.75±3.47） mmHg （P 〈0.01）.But neither right atrial end-systolic diameter （RASD） nor right ventricular end-diastolic diameter （RVDD） in the PE patients had changed when compared with the controls.The 6-minute walk distance was significantly reduced in the PE patients compared with normal subjects,（447.81±79.20） m vs.（513.75±31.45） m （P 〈0.01）.Both anaerobic threshold oxygen consumption （VO2AT） and peak oxygen consumption （VO2peak） were significantly lower in patients with PE,while CO2 equivalent ventilation （VE/VCO2 slope） was higher;VO2AT （9.44±3.82） ml·kg1.min-1 vs.（14.62±2.93） ml.kg-1.min-1 （P 〈0.01） and VO2peak （12.26±4.06） ml.kg-1.min-1 vs.（23.46±6.15） ml.kg-1.min-1 （P 〈0.01） and VE/VCO2 slope 35.47±6.66 vs.26.94±3.16 （P 〈0.01）.There was no significant difference in resting cardiac output （CO） between the PE and normal groups展开更多
Background Lower exercise tolerance is an important component of asthma and the possible effects of non-invasive ven-tilation on exercise capacity in individuals with severe therapy-resistant asthma(STRA)are unknown.T...Background Lower exercise tolerance is an important component of asthma and the possible effects of non-invasive ven-tilation on exercise capacity in individuals with severe therapy-resistant asthma(STRA)are unknown.This study aimed to evaluate the immediate effect of continuous positive airway pressure(CPAP)on exercise tolerance in children with STRA.Methods We performed a controlled,randomized,crossover clinical trial including subjects aged 6 to 18 years old diagnosed with STRA.Clinical,anthropometric and lung function data were collected.The participants in the intervention group(IG)used CPAP(PEEP 10cmH2O and FiO20.21)for a period of 40 min.Subjects in the control group(CG)used CPAP with mini-mum PEEP at 1 cmH20 also for 40 min.Afterwards,subjects from both groups underwent cardiopulmonary exercise testing(CPET).After a 15-day washout period,on a subsequent visit,subjects participated in the opposite group to the initial one.Results Thirteen subjects with a mean age of 12.30±1.7 years were included.The variables of peak expiratory flow(PEF)and forced expiratory volume in the first second(FEV1)before using CPAP and after performing CPET did not show sig-nificant differences.Regarding CPET results,there was no significant difference(P=0.59)between groups at peak exercise for oxygen consumption—VO2(CG:33.4±6.3 and IG:34.5±5.9,mL kg^(-1)min^(-1)).However,the IG(12.4±2.1)presented a total test time(min)significantly(P=0.01)longer than the CG(11.5±1.3).Conclusion The results suggest that the use of CPAP before physical exercise increases exercise duration in children and adolescents with STRA.展开更多
The purpose of this study was to find out the type of relationship between VO2 max and percentage of body fat in male secondary school students. The research sample consisted of 30 male students studying at Al-Khawari...The purpose of this study was to find out the type of relationship between VO2 max and percentage of body fat in male secondary school students. The research sample consisted of 30 male students studying at Al-Khawarizmi High School in Tlemcen. Their average age was 16.56 ± 0.69. We based our research on books and scientific journals, site visits, and personal meeting. We used the descriptive approach. The test was carried out and the measurements were taken at the institution＇s yard and the doctor＇s office respectively. We used the running test for one mile to measure the maximum oxygen consumption. The skin folds were taken in three areas： the chest, abdomen and mid-thigh, to estimate the proportion of fat in the body. The results showed that the relationship between maximum oxygen consumption and body fat percentage was strongly reversed at a significant level of 0.01, with Pearson correlation coefficient -0.597.展开更多
Objectives To assess the relationship between peak oxygen consumption （PVO2） and the ambulation distance in six-minute walk test （6MWT）among the healthy subjects. Methods The 51 healthy subjects were recruited for...Objectives To assess the relationship between peak oxygen consumption （PVO2） and the ambulation distance in six-minute walk test （6MWT）among the healthy subjects. Methods The 51 healthy subjects were recruited for the six-minute walk test. Data of pulmonary gas exchange breath by breath, such as VO2 , VCO2 were real-time measured with wireless remote sensing K4B2, so to study the relationship between peak oxygen uptake and the ambulation distance. Results It was noticed that there was a positive linear correlation between the ambulation distance and PVO2 （ r =0. 619, P 〈0. 001 ） in six-minute walk test. The regression equation was set up （ VO2/kg =0. 05D -6. 331, P 〈 0. 001 ）. PVO2 〉 PVCO2 ,R 〈 1 were found,which suggested that 6MWT was a test below anaerobic threshold. Conclusions There was a closely positive linear correlation between the ambulation distance and PVO2, which is safety, convenient and valuable for the evaluation of cardiopulmonary function and the treatment of cardiopulmonary rehabilitation.展开更多
基金financial support provided by the National Key Technology R&D Program during the 11th Five-Year Period (No. 2006BAK03B05)the National Natural Science Foundation of China (Nos.50534090, 50674090 and 50804047)+1 种基金the Research Fund of the State Key Laboratory of Coal Resources and Mine Safety, China University of Mining and Technology (Nos.08KF14 and SKLCRSM09X04)the Scien-tific Research Foundation of China University of Mining & Technology (No.2007A001)
文摘In order to investigate the oxidation kinetics of gas coal at low temperatures, we derived a rate equation of oxygen consumption during low-temperature oxidation of gas coal and deduced an E-c equation, expressing the relation between active energy E and oxygen concentration c. The reaction order n and active energy E were calculated with this equation based on experiments of static oxygen consumption tests. In addition, we proved the rationality of the E-c equation using a kinetic compensation effect and obtained the isokinetic temperature Tc. The results show that： 1） the gas coal oxidizes easily with increasing temperature and the oxidation tends to be spontaneous at higher temperatures; 2） the oxygen concentration c affects oxygen consumption very much at lower temperatures but has only a small effect at higher temperatures; 3） the isokinetic temperature Tc was 127 ℃ which has been experimentally validated as the key turning point during low-temperature spontaneous combustion of gas coal.
文摘Background There is no research,either at home or abroad,focusing on assessing the cardiopulmonary functional reserve and exercise tolerance in patients with pulmonary embolism （PE）,but the benefits of early exercise are well recognized.The goals of this study were to assess cardiopulmonary functional reserve in treated PE patients using the inert gas rebreathing method of the cardiopulmonary exercise test （CPET）,and to compare it with traditional methods.Methods CPET on the bicycle ergometer were performed in 40 patients with age,gender,body mass index,systolic blood pressure,and pulmonary function matched.The first group was the PE group composed of 16 PE patients （5 male,11 female） who were given the standard antithrombotic therapy for two weeks.The second group was composed of 24 normal individuals （10 male,14 female）.Both groups were evaluated by cardiac ultrasound examination,6-minute walking test （6MVVT）,and CPET.Results （1） Right ventricular systolic pressure （RVSP） in the PE group increased significantly compared to the control group,（34.81±8.15） mmHg to （19.75±3.47） mmHg （P 〈0.01）.But neither right atrial end-systolic diameter （RASD） nor right ventricular end-diastolic diameter （RVDD） in the PE patients had changed when compared with the controls.The 6-minute walk distance was significantly reduced in the PE patients compared with normal subjects,（447.81±79.20） m vs.（513.75±31.45） m （P 〈0.01）.Both anaerobic threshold oxygen consumption （VO2AT） and peak oxygen consumption （VO2peak） were significantly lower in patients with PE,while CO2 equivalent ventilation （VE/VCO2 slope） was higher;VO2AT （9.44±3.82） ml·kg1.min-1 vs.（14.62±2.93） ml.kg-1.min-1 （P 〈0.01） and VO2peak （12.26±4.06） ml.kg-1.min-1 vs.（23.46±6.15） ml.kg-1.min-1 （P 〈0.01） and VE/VCO2 slope 35.47±6.66 vs.26.94±3.16 （P 〈0.01）.There was no significant difference in resting cardiac output （CO） between the PE and normal groups
文摘Background Lower exercise tolerance is an important component of asthma and the possible effects of non-invasive ven-tilation on exercise capacity in individuals with severe therapy-resistant asthma(STRA)are unknown.This study aimed to evaluate the immediate effect of continuous positive airway pressure(CPAP)on exercise tolerance in children with STRA.Methods We performed a controlled,randomized,crossover clinical trial including subjects aged 6 to 18 years old diagnosed with STRA.Clinical,anthropometric and lung function data were collected.The participants in the intervention group(IG)used CPAP(PEEP 10cmH2O and FiO20.21)for a period of 40 min.Subjects in the control group(CG)used CPAP with mini-mum PEEP at 1 cmH20 also for 40 min.Afterwards,subjects from both groups underwent cardiopulmonary exercise testing(CPET).After a 15-day washout period,on a subsequent visit,subjects participated in the opposite group to the initial one.Results Thirteen subjects with a mean age of 12.30±1.7 years were included.The variables of peak expiratory flow(PEF)and forced expiratory volume in the first second(FEV1)before using CPAP and after performing CPET did not show sig-nificant differences.Regarding CPET results,there was no significant difference(P=0.59)between groups at peak exercise for oxygen consumption—VO2(CG:33.4±6.3 and IG:34.5±5.9,mL kg^(-1)min^(-1)).However,the IG(12.4±2.1)presented a total test time(min)significantly(P=0.01)longer than the CG(11.5±1.3).Conclusion The results suggest that the use of CPAP before physical exercise increases exercise duration in children and adolescents with STRA.
文摘The purpose of this study was to find out the type of relationship between VO2 max and percentage of body fat in male secondary school students. The research sample consisted of 30 male students studying at Al-Khawarizmi High School in Tlemcen. Their average age was 16.56 ± 0.69. We based our research on books and scientific journals, site visits, and personal meeting. We used the descriptive approach. The test was carried out and the measurements were taken at the institution＇s yard and the doctor＇s office respectively. We used the running test for one mile to measure the maximum oxygen consumption. The skin folds were taken in three areas： the chest, abdomen and mid-thigh, to estimate the proportion of fat in the body. The results showed that the relationship between maximum oxygen consumption and body fat percentage was strongly reversed at a significant level of 0.01, with Pearson correlation coefficient -0.597.
文摘Objectives To assess the relationship between peak oxygen consumption （PVO2） and the ambulation distance in six-minute walk test （6MWT）among the healthy subjects. Methods The 51 healthy subjects were recruited for the six-minute walk test. Data of pulmonary gas exchange breath by breath, such as VO2 , VCO2 were real-time measured with wireless remote sensing K4B2, so to study the relationship between peak oxygen uptake and the ambulation distance. Results It was noticed that there was a positive linear correlation between the ambulation distance and PVO2 （ r =0. 619, P 〈0. 001 ） in six-minute walk test. The regression equation was set up （ VO2/kg =0. 05D -6. 331, P 〈 0. 001 ）. PVO2 〉 PVCO2 ,R 〈 1 were found,which suggested that 6MWT was a test below anaerobic threshold. Conclusions There was a closely positive linear correlation between the ambulation distance and PVO2, which is safety, convenient and valuable for the evaluation of cardiopulmonary function and the treatment of cardiopulmonary rehabilitation.
