Objective To study the effects of obstructive sleep apneas on endothelial function and autonomic modulation. Methods From June 2009 to June 2011, male patients with obstructive sleep apnea hypopnea syndrome (OSAHS) we...Objective To study the effects of obstructive sleep apneas on endothelial function and autonomic modulation. Methods From June 2009 to June 2011, male patients with obstructive sleep apnea hypopnea syndrome (OSAHS) were consecutively enrolled in this study. Patients with an apnea/hypopnea index (AHI) of greater than 15 and without previous treatment for OSAHS were included as Group OSAHS and obese subjects with an AHI of less than 5 were included as non-OSAHS controls (Group Control). Electrocardiography and beat-to-beat blood pressure were continuously recorded from the radial artery by applanation tonometry which was synchronized with polysomnography recording. Endothelial function was measured by arterial augmentation index (AAI). Spectral analysis of heart rate variability (HRV) and blood pressure variability (BPV) were computed for cardiac parasympathetic modulation (high frequency power, HF); sympathetic modulation (low frequency power, LF), sympathovagal balance (LF/HF power of R-R variability, LF/HF) and BPV sympathetic modulation (BPV LF) in normalized units [total power of the components/(total power-very LF power)×100]. Results Finally, 27 moderate-severe OSAHS patients and 22 non-OSAHS obese controls were recruited in the Group OSAHS and Group Control, respectively. In Group OSAHS, the age was 43.3±9.3 year-old, body mass index (BMI) was 36.8±8.7 kg/m 2 ; in Group Control, the age was 42.9±8.6 year-old, BMI was 34.4±7.9 kg/m 2 ; there were no significant differences in age and BMI between the Group OSAHS and Group Control (all P>0.05). The baseline AAI (12.5%±2.2% vs. 8.2%±2.1%) and BPV LF (68.3%±13.5% vs. 61.1%±11.7%) of the Group OSAHS were significantly higher than those of the Group Control (all P<0.05). And after overnight sleep, systolic BP (143.7±14.2 vs. 132.8±13.3 mm Hg), diastolic BP (87.7±7.7 vs. 78.6±5.5 mm Hg), HRV LF (69.7%±14.4% vs. 64.3%±12.1%), HRV LF/HF (3.7±2.0 vs. 2.3±1.3) and BPV LF (77.8%±15.6% vs. 68.3%±13.5%) of the Group OSAHS were significantly increased (all P<0.001), while HRV HF was significantly decreased (21.1%±9.3% vs. 27.5%±10.3%, P<0.05) from baseline.Conclusions The baseline endothelial function and autonomic modulation are impaired in OSAHS patients, which happened prior to hypertension and other cardiovascular complications. And the load effects of overnight obstructive breathing events could induce blood pressure and sympathetic activity increasing in the morning in OSAHS patients without acute aggravation in endothelial dysfunction.展开更多
Equalization can compensate channel distortion caused by channel multipath effects, and effectively improve convergent of modulation constellation diagram in optical wireless system. In this paper, the subspace blind ...Equalization can compensate channel distortion caused by channel multipath effects, and effectively improve convergent of modulation constellation diagram in optical wireless system. In this paper, the subspace blind equalization algorithm is used to preprocess M-ary phase shift keying(MPSK) subcarrier modulation signal in receiver. Mountain clustering is adopted to get the clustering centers of MPSK modulation constellation diagram, and the modulation order is automatically identified through the k-nearest neighbor(KNN) classifier. The experiment has been done under four different weather conditions. Experimental results show that the convergent of constellation diagram is improved effectively after using the subspace blind equalization algorithm, which means that the accuracy of modulation recognition is increased. The correct recognition rate of 16 PSK can be up to 85% in any kind of weather condition which is mentioned in paper. Meanwhile, the correct recognition rate is the highest in cloudy and the lowest in heavy rain condition.展开更多
基金Supported by a grant from National Natural Science Foundation of China (81070072)
文摘Objective To study the effects of obstructive sleep apneas on endothelial function and autonomic modulation. Methods From June 2009 to June 2011, male patients with obstructive sleep apnea hypopnea syndrome (OSAHS) were consecutively enrolled in this study. Patients with an apnea/hypopnea index (AHI) of greater than 15 and without previous treatment for OSAHS were included as Group OSAHS and obese subjects with an AHI of less than 5 were included as non-OSAHS controls (Group Control). Electrocardiography and beat-to-beat blood pressure were continuously recorded from the radial artery by applanation tonometry which was synchronized with polysomnography recording. Endothelial function was measured by arterial augmentation index (AAI). Spectral analysis of heart rate variability (HRV) and blood pressure variability (BPV) were computed for cardiac parasympathetic modulation (high frequency power, HF); sympathetic modulation (low frequency power, LF), sympathovagal balance (LF/HF power of R-R variability, LF/HF) and BPV sympathetic modulation (BPV LF) in normalized units [total power of the components/(total power-very LF power)×100]. Results Finally, 27 moderate-severe OSAHS patients and 22 non-OSAHS obese controls were recruited in the Group OSAHS and Group Control, respectively. In Group OSAHS, the age was 43.3±9.3 year-old, body mass index (BMI) was 36.8±8.7 kg/m 2 ; in Group Control, the age was 42.9±8.6 year-old, BMI was 34.4±7.9 kg/m 2 ; there were no significant differences in age and BMI between the Group OSAHS and Group Control (all P>0.05). The baseline AAI (12.5%±2.2% vs. 8.2%±2.1%) and BPV LF (68.3%±13.5% vs. 61.1%±11.7%) of the Group OSAHS were significantly higher than those of the Group Control (all P<0.05). And after overnight sleep, systolic BP (143.7±14.2 vs. 132.8±13.3 mm Hg), diastolic BP (87.7±7.7 vs. 78.6±5.5 mm Hg), HRV LF (69.7%±14.4% vs. 64.3%±12.1%), HRV LF/HF (3.7±2.0 vs. 2.3±1.3) and BPV LF (77.8%±15.6% vs. 68.3%±13.5%) of the Group OSAHS were significantly increased (all P<0.001), while HRV HF was significantly decreased (21.1%±9.3% vs. 27.5%±10.3%, P<0.05) from baseline.Conclusions The baseline endothelial function and autonomic modulation are impaired in OSAHS patients, which happened prior to hypertension and other cardiovascular complications. And the load effects of overnight obstructive breathing events could induce blood pressure and sympathetic activity increasing in the morning in OSAHS patients without acute aggravation in endothelial dysfunction.
基金supported by the National Natural Science Foundation of China(No.61671375)the Industrial Research of Science and Technology Plan of Shaanxi Province(No.2016GY-082)
文摘Equalization can compensate channel distortion caused by channel multipath effects, and effectively improve convergent of modulation constellation diagram in optical wireless system. In this paper, the subspace blind equalization algorithm is used to preprocess M-ary phase shift keying(MPSK) subcarrier modulation signal in receiver. Mountain clustering is adopted to get the clustering centers of MPSK modulation constellation diagram, and the modulation order is automatically identified through the k-nearest neighbor(KNN) classifier. The experiment has been done under four different weather conditions. Experimental results show that the convergent of constellation diagram is improved effectively after using the subspace blind equalization algorithm, which means that the accuracy of modulation recognition is increased. The correct recognition rate of 16 PSK can be up to 85% in any kind of weather condition which is mentioned in paper. Meanwhile, the correct recognition rate is the highest in cloudy and the lowest in heavy rain condition.
