Using impedance-plethysmography, variations in volume of blood-flow of the calves of 34 young adults were observed under different postures: lying, sitting, standing and squatting.Results showed that blood-flow of the calf was of bigger volume in lying position, smaller volume while standing, still smaller while sitting and still smaller while squatting.Data thus obtained are similar to those by other authors using other methods. If the devices used can be further improyed, dynamic measurement of blood-flow volume of human extremities during physical exercises will also be possible.

Objective To measure the activity energy expenditure(AEE) of healthy adults during level walking by using indirect calorimetry,and to analyze the characteristics and underlying influencing factors such as age and gender. Methods A total of 60 healthy adults aged 20-50 years (30 males and 30 femdes) participated in the study.All the subjects were divided into six groups by gender and age (the age span of each group was 10 years). The subjects were arranged to walk at speeds of 3.5,4.5,5.5km/h and run at 5.5,6.5,7.5km/h, respectively, on the treadmill. The resting energy expenditure ( REE ) and AEE were measured during walking and running at different speeds.There was a 5-minute rest among the test sessions. Results No difference in terms of AEE between the female and male at the same age ( P ＞ 0. 05 ). During 3.5km/h walking,AEE of 21-30 year-old females was lower than 31-40 yearold females and males( P ＜0.05 ) ;During 4.5km/h walking,AEE of 31-40 year-old females was higher than 21-30 yearold females and males and 41-50 year-old females; AEE of 21-30 year-old females was lower than 41-50 year-old males (P ＜ 0.05 ) ;During 5.5km/h walking,AEE of 31-40 year-old females was higher than 21-30 year-old females and males ( P ＜ 0. 05 ). During 6.5 km/h running, AEE of 31-40 year-old females was higher than 41-50 year-old females ( P ＜0.05), while during 7.5km/h running, AEE of 21-30 year-old males was higher than 41-50 year-old females (P ＜0.05 ). It was also found that the AEE of all groups except the 41-50 year-old females group was higher when walking at the speed of 5.5km/h than running at the same speed( P ＜ 0.05 ). Conclusions Age has more effect on REE and AEE than the gender. AEE of elder subjects is higher than that of the younger ones during walking, however, AEE of younger people increases faster than the elders during running. AEE of 31-40 year-old females is the highest in all groups both in walking and running. AEE in running is higher than in walking at the same speed.

In order to find the most suitable algorithm of T-wave end point detection for clinical detection, we tested three methods, which are not just dependent on the threshold value of T-wave end point detection, i. e. wavelet method, cumulative point area method and trapezium area method, in PhysioNet QT database (20 records with 3 569 beats each). We analyzed and compared their detection performance. First, we used the wavelet method to locate the QRS complex and T-wave. Then we divided the T-wave into four morphologies, and we used the three algorithms mentioned above to detect T-wave end point. Finally, we proposed an adaptive selection T-wave end point detection algorithm based on T-wave morphology and tested it with experiments. The results showed that this adaptive selection method had better detection performance than that of the single T-wave end point detection algorithm. The sensitivity, positive predictive value and the average time errors were 98.93%, 99.11% and (--2.33 ± 19.70) ms, respectively. Consequently, it can be concluded that the adaptive selection algorithm based on T-wave morphology improves the efficiency of T-wave end point detection.
Algorithms ; Electrocardiography ; Humans ; Wavelet Analysis

Objective: To investigate the effects on human peripheral blood erythrocytes of long-term occupational contact with chromate. Methods: A dynamic cohort study was conducted of chromate-exposed workers (343 cases) and non-chromate-exposed workers (73 cases) at a chromate production enterprise who were selected according to specific inclusion and exclusion criteria from 2010 to 2015. Personal information and chromate exposure information were obtained by questionnaire. A generalized estimating equation was employed to analyze the effects on human peripheral blood erythrocytes of long-term occupational contact with chromate, controlling for age, gender, smoking, alcohol consumption and body mass index. Results: The mean ages and working ages of those entering the cohort study were 36.67 ±6.78 and 38.47 ± 7.18, respectively, for the exposure group and 8.39 ± 6.02 and 12.86 ± 8.34, respectively, for the control group. The erythrocyte content [(4.73±0.46), (4.81±0.53), (4.41±0.45)]×10¹²/L in the peripheral blood in the chromate exposure group was lower than that [(4.76±0.42), (4.95±0.45), (4.47±0.39)]×10¹²/L in the control group for the years 2010, 2011, 2012 and 2014 (t values were 0.38, 1.96, 0.92 and 1.21; P values were 0.703, 0.051, 0.358 and 0.227, respectively). The correlations between the years 2010 and 2011, 2011 and 2012, 2012 and 2014, and 2014 and 2015 were 0.667, 0.464,-0.070 and 0.020, respectively (P<0.001). The RR for males and those that consumed alcohol were 0.661 (95% CI: 0.616-0.709) and 0.910 (95% CI: 0.811- 1.201), respectively. Compared with the control group, the risk of reduced erythrocyte levels in the peripheral blood was increased by 0.915 (95% CI: 0.852- 0.982) in the chromate-exposed group. Conclusions The erythrocyte content of peripheral blood was reduced after long-term exposure to chromate. Maleness and alcohol consumption were factors that increased the risk of reduced peripheral blood erythrocytes in the chromate-exposed population.

Objective To evaluate the long-term efficacy of cervical artificial disc replacement for patients with degenerative cervical canal stenosis.Methods All of 43 patienta underwent single level Bryan cervical artificial disc replacement for degenerative cervical canal stenosis were retrospectively analyzed with a minimum 10 years follow-up in our hospital between December 2003 and December 2007.There were 28 males and 15 females with an average age of 56.7 ± 8.0 years which ranged from 37 to 76 including 1 case of C3.4 level,11 xases of ~ level,26 cases of C~ level and 5 cases of C6,7 level.According to the symptoms and location of compression on radiograph,the patients were divided into 3 groups:15 patients in radiculopathy group,10 patients in myelopathy group and 18 patients in myeloradiculo p~hy group.Radidogical evaluation indexes include global range of motion (ROM),segmental ROM,segmental Cobb angle.Clinical evaluation indexes including Japanese Orthopaedic Association (JOA) score,neck disability index (NDI) and Odom's criteria.The variable data were analyzed by one-way ANOVA,the grading data were analyzed by Kruskal-Wallis H test.The preoperative and postoperative data were analyzed by paired t test.Results At the last follow-up,the Cobb angle of the operative segment was 1.29°±1.34°in myelopathy group(t=4.606,P=0.001),0.71°±2.20°in radiculopathy group (t=2.355,P=0.034),and 0.69°±2.12° in myeloradiculopathy group (t=3.312,P=0.004),which was significantly lower than that before operation.At the last follow-up,ROM of the operative segment in myelopathy group was 6.41 o ±4.87°,which was significantly lower than that before operation (11.46° ±5.19°,t=3.589,P＜ 0.05),and there was no significant difference in the other two groups.There was no significant difference in other imaging parameters among the three groups.JOA scores at the last follow-up were 16.33±0.75 in radiculopathy group (t=5.857,P＜ 0.001),16.00±1.05 in myelopathy group(t=8.337,P＜ 0.001) and 14.78±1.69 in radiculopathy group (t=4.045,P＜ 0.001);NDI were 13.07％±5.90％ in radiculopathy group (t=7.097,P＜ 0.001),12.60％±4.22％ in myelopathy group (t=7.319,P＜ 0.001) and 23.11％±14.18％ in radiculopathy group (t=4.229,P＜ 0.001),which were all significantly improved than those before operation.The excellent and good rate of Odom's criteria (H=2.719,2.411,P＜ 0.05),JOA (LAD-t=3.770,4.080,P＜0,05) and NDI(LAD-t=2.850,2.643,P＜ 0.05) at the last follow-up of the patients in radiculopathy group and myelopathy group were better than those of patients in myeloradiculopathy group (P＜ 0.05).Conclusion Cervical artificial disc replacement has a satisfied long-term clinical efficacy with degenerative cervical canal stenosis.The efficacy of myelopathy and radiculopathy were better than myeloradiculopathy.

Objective:To investigate chromosomal aberrations in peripheral blood lymphocytes of underground miners, in order to explore the influencing factors involved in chromosomal aberration levels of non-uranium metal mines.Methods:Totall 135 workers were recruited from an iron mine and a gold mine located in different cities of Henan province, where 69 workers worked aboveground and 66 miners worked underground in the metal mines. The radon concentration in the mines was measured by solid-state nuclear track detectors. Chromosomal aberrations in peripheral blood lymphocytes from the subjects were detected using conventional analysis method, and the influence factors of chromosomal aberrations were analyzed.Results:Radon concentration was 30-2 943 Bq/m 3 in the aboveground workplace of the mines, and 62-28 314 Bq/m 3 in underground. The age of the underground group was obviously lower than that of the aboveground group( t=2.12, P<0.05), but the frequencies of dicentrics, translocation, acentric fragment, and total chromosome-type aberrations in the underground group were significantly higher than those in the aboveground group ( χ2=10.49, 16.74, 8.15, 29.50, P<0.01). Consistent results were obtained when only male workers were regarded as object of observation ( χ2=8.44, 11.63, 4.94, 20.81, P<0.05). The frequency of translocation ( χ2=8.44, P<0.05) was dependent on the length of service in the underground group. Poisson regression analysis indicated that the aboveground and undergroud grouping partly affected the levels of dicentrics, translocation, acentric fragment, and total chromosome-type aberrations (the underground group IRR=3.25, 2.69, 1.97, 2.18, P<0.05). Conclusions:The radon exposure in the underground workplace of the metal mines may be the main factor resulting in the increase of chromosome-type aberrations of miners. The occupational health and safety of the miners who may be exposed to high radon levels are worthy of great attention.

Indirect energy metabolism measurement is the gold standard for providing nutritional support for critical illness. The accuracy of the measurement data directly affects the outcome of the disease. In order to study the influence of sampling delay on the accuracy of energy metabolism measurement under mechanical ventilation, the Matlab/Simulink platform and respiratory electrical model were used for simulation and quantitative analysis. The results show that the error of indirect energy metabolism measurement increases with the increase of sampling delay, the error of sampling delay in mechanical ventilation mode is larger than that of spontaneous breathing, and the error of sampling delay in PCV mode of mechanical ventilation is larger than that in VCV mode. Therefore, there should be different sampling delay compensation strategies under severe mechanical ventilation and its different control modes.
Computer Simulation ; Critical Illness ; Energy Metabolism ; Humans ; Respiration, Artificial

A lung diffusion function detection system is designed. Firstly, the controllable collection of air, test gas source and calibration gas source was based on single-breath method measurement principle. Secondly, pulmonary diffusing capacity for carbon monoxide (D_lCO) was calculated by gas concentration measured by the non-dispersive infrared sensor to measure, the gas flow measured by the differential pressure sensor, and the temperature, humidity and atmospheric pressure sensors to test and evaluate the quantitative detection and evaluation of lung diffusion function. Moreover, a preliminary verification of the lung diffusion function detection system was implemented, and the results showed that the error of the lung carbon monoxide diffusion and the alveolar volume did not exceed 5%. Therefore, the system has high accuracy and is of great value for early screening and accurate assessment of COPD.
Carbon Monoxide ; Lung ; Pulmonary Diffusing Capacity/methods*