Objective: This study aims to investigate the drainage effect and clinical outcomes of negative pressure chest drainage in patients after two-port thoracoscopic valve surgery, comparing the differences in postoperativ...Objective: This study aims to investigate the drainage effect and clinical outcomes of negative pressure chest drainage in patients after two-port thoracoscopic valve surgery, comparing the differences in postoperative pain, hospital stay, and other factors between the negative pressure group and the control group. Methods: This study is a prospective controlled trial that selected patients undergoing two-port thoracoscopic valve surgery at a certain hospital from January 2019 to December 2024. Patients were randomly assigned to the control group and the negative pressure group using a random number table method. The control group consisted of 30 patients (20 males, 10 females, mean age 42.03 ± 12.89 years), and the negative pressure group consisted of 35 patients (26 males, 9 females, mean age 41.84 ± 11.83 years). The control group received traditional chest drainage, while the negative pressure group received negative pressure chest drainage. Postoperative pain scores, hospital stay, drainage time, number of tube blockages, and incidences of pneumothorax or subcutaneous emphysema were recorded and statistically analyzed. Results: The negative pressure group had a significantly shorter postoperative drainage time compared to the control group (49.09 ± 11.99 hours vs. 79.10 ± 7.32 hours, P < 0.001). The postoperative pain score was lower in the negative pressure group (4.49 ± 1.27 vs. 7.03 ± 0.85, P < 0.001), and the hospital stay was significantly shorter (9.83 ± 1.69 days vs. 14.73 ± 2.32 days, P < 0.001). The incidence of pneumothorax or subcutaneous emphysema was significantly lower in the negative pressure group than in the control group (14.29% vs. 56.67%, P = 0.0003). Conclusion: The application of negative pressure chest drainage in patients after two-port thoracoscopic valve surgery can effectively reduce postoperative pain, shorten hospital stay, and lower the incidence of tube blockage and pneumothorax, demonstrating good clinical outcomes.展开更多
Simple and efficient surface acoustic wave （SAW） two-port resonators with low insertion loss and high Q-values on ST-X quartz substrate using a corrosion-proof A1/Au-stripe electrode structure are developed for gas ...Simple and efficient surface acoustic wave （SAW） two-port resonators with low insertion loss and high Q-values on ST-X quartz substrate using a corrosion-proof A1/Au-stripe electrode structure are developed for gas sensing. It was composed of two shorted grating reflectors and adjacent intedigital transducers （IDT）, and an active metal film in the cavity between the IDTs for the sensitive film coating. The devices are expected to provide good protection towards metal electrode for gas sensors application in chemically reactive environments. Excellent device performance as low insertion loss, high Q factor and single-mode are achieved by carefully selecting the metallic electrode thickness, cavity length and acoustic aperture. Prior to fabrication, the coupling of modes （COM） model was performed for device simulation to determine the optimal design parameters. The fabricated single-mode SAW resonator at operation frequency of 300 MHz range exhibits matched insertion loss of ~6.5 dB and loaded Q factor in the 3000 range. Using the fabricated resonator as the feedback element, a duaresonator-oscillator with excellent frequency stability （0.1 ppm） was developed and evaluated experimentally, and it is significant for performance improvement of SAW gas sensor.展开更多
THE low-noise preamplifier, as one of the major circuits in signal detection system, consists ofthe low noise amplifier and the feedback network. The low noise amplifier design aims both tocalculate the optimal source...THE low-noise preamplifier, as one of the major circuits in signal detection system, consists ofthe low noise amplifier and the feedback network. The low noise amplifier design aims both tocalculate the optimal source impedance and minimum noise figure, and to compare the noiseperformance and other characteristics of variant circuits and components. The conventional ap-proach to noise analysis of an electronic circuit is to calculate the output noise power of the展开更多
目的探讨肥胖患者施行经脐单孔腹腔镜手术(transumbilical laparoendoscopic single site surgery,TU-LESS)加一个操作孔的两孔腹腔镜子宫肌瘤剔除术的安全性。方法回顾性分析2020年7月~2023年7月139例两孔腹腔镜子宫肌瘤剔除术资料,其...目的探讨肥胖患者施行经脐单孔腹腔镜手术(transumbilical laparoendoscopic single site surgery,TU-LESS)加一个操作孔的两孔腹腔镜子宫肌瘤剔除术的安全性。方法回顾性分析2020年7月~2023年7月139例两孔腹腔镜子宫肌瘤剔除术资料,其中24例体重指数(BMI)≥28,115例BMI<28。TU-LESS入路基础上在左下腹增加一个5 mm辅助操作孔,使用传统腹腔镜及手术器械实施手术。比较2组围术期指标。结果1例(BMI 31.6)因手术操作困难增加第2个辅助孔,其余138例均未中转手术方式,术中、术后未出现严重并发症。2组手术时间、术中出血量、手术前后血红蛋白差值、术后首次排气时间、术后24 h疼痛视觉模拟评分(Visual Analogue Scale,VAS)、术后发热、术后住院时间、住院费用差异均无显著性(P>0.05)。结论肥胖患者行TU-LESS加一个操作孔的两孔腹腔镜子宫肌瘤剔除术安全、可行。展开更多
The startup process of a thermoacoustic engine is a self-excited oscillation process generated in inhomogeneous acoustic media.To reveal these coupling relations between various influential factors is an important tas...The startup process of a thermoacoustic engine is a self-excited oscillation process generated in inhomogeneous acoustic media.To reveal these coupling relations between various influential factors is an important task of basic research on thermoacoustics.In this paper thermoacoustic engines are regarded as thermoacoustic oscillators consisting of the active network and the passive network.Accordingly,the two-port Y-parameter for relevant component is derived,and standing wave and traveling wave thermoacoustic engine are described by the negative-resistance and feedback model,respectively.The relevant two-port network topology is given as well.The startup criteria for thermoacoustic oscillators are obtained by using Nyquist instability criterion.The model prediction of startup parameters,particularly,startup frequency and mode characteristic are in agreement with that of experimental results reported in the literature.Moreover,with topological graphs it is verified that standing wave engines would start up in a negative-resistance state and there would exist high frequency modes in thermoacoustic-Stirling engines.By investigating into the frequency response of thermoacoustic system,this method proposed can achieve such an objective that these effects of operating and structural parameters of engine on startup modes and startup temperature can be revealed in an analytical way.Thus this approach to test and check thermal stability can be provided in a design phase,instead of using empirical frequency to design thermoacoustic systems.展开更多
文摘Objective: This study aims to investigate the drainage effect and clinical outcomes of negative pressure chest drainage in patients after two-port thoracoscopic valve surgery, comparing the differences in postoperative pain, hospital stay, and other factors between the negative pressure group and the control group. Methods: This study is a prospective controlled trial that selected patients undergoing two-port thoracoscopic valve surgery at a certain hospital from January 2019 to December 2024. Patients were randomly assigned to the control group and the negative pressure group using a random number table method. The control group consisted of 30 patients (20 males, 10 females, mean age 42.03 ± 12.89 years), and the negative pressure group consisted of 35 patients (26 males, 9 females, mean age 41.84 ± 11.83 years). The control group received traditional chest drainage, while the negative pressure group received negative pressure chest drainage. Postoperative pain scores, hospital stay, drainage time, number of tube blockages, and incidences of pneumothorax or subcutaneous emphysema were recorded and statistically analyzed. Results: The negative pressure group had a significantly shorter postoperative drainage time compared to the control group (49.09 ± 11.99 hours vs. 79.10 ± 7.32 hours, P < 0.001). The postoperative pain score was lower in the negative pressure group (4.49 ± 1.27 vs. 7.03 ± 0.85, P < 0.001), and the hospital stay was significantly shorter (9.83 ± 1.69 days vs. 14.73 ± 2.32 days, P < 0.001). The incidence of pneumothorax or subcutaneous emphysema was significantly lower in the negative pressure group than in the control group (14.29% vs. 56.67%, P = 0.0003). Conclusion: The application of negative pressure chest drainage in patients after two-port thoracoscopic valve surgery can effectively reduce postoperative pain, shorten hospital stay, and lower the incidence of tube blockage and pneumothorax, demonstrating good clinical outcomes.
基金supported by the National Nature Science Foundation of China(11074268,10834010)
文摘Simple and efficient surface acoustic wave （SAW） two-port resonators with low insertion loss and high Q-values on ST-X quartz substrate using a corrosion-proof A1/Au-stripe electrode structure are developed for gas sensing. It was composed of two shorted grating reflectors and adjacent intedigital transducers （IDT）, and an active metal film in the cavity between the IDTs for the sensitive film coating. The devices are expected to provide good protection towards metal electrode for gas sensors application in chemically reactive environments. Excellent device performance as low insertion loss, high Q factor and single-mode are achieved by carefully selecting the metallic electrode thickness, cavity length and acoustic aperture. Prior to fabrication, the coupling of modes （COM） model was performed for device simulation to determine the optimal design parameters. The fabricated single-mode SAW resonator at operation frequency of 300 MHz range exhibits matched insertion loss of ~6.5 dB and loaded Q factor in the 3000 range. Using the fabricated resonator as the feedback element, a duaresonator-oscillator with excellent frequency stability （0.1 ppm） was developed and evaluated experimentally, and it is significant for performance improvement of SAW gas sensor.
文摘THE low-noise preamplifier, as one of the major circuits in signal detection system, consists ofthe low noise amplifier and the feedback network. The low noise amplifier design aims both tocalculate the optimal source impedance and minimum noise figure, and to compare the noiseperformance and other characteristics of variant circuits and components. The conventional ap-proach to noise analysis of an electronic circuit is to calculate the output noise power of the
文摘目的探讨肥胖患者施行经脐单孔腹腔镜手术(transumbilical laparoendoscopic single site surgery,TU-LESS)加一个操作孔的两孔腹腔镜子宫肌瘤剔除术的安全性。方法回顾性分析2020年7月~2023年7月139例两孔腹腔镜子宫肌瘤剔除术资料,其中24例体重指数(BMI)≥28,115例BMI<28。TU-LESS入路基础上在左下腹增加一个5 mm辅助操作孔,使用传统腹腔镜及手术器械实施手术。比较2组围术期指标。结果1例(BMI 31.6)因手术操作困难增加第2个辅助孔,其余138例均未中转手术方式,术中、术后未出现严重并发症。2组手术时间、术中出血量、手术前后血红蛋白差值、术后首次排气时间、术后24 h疼痛视觉模拟评分(Visual Analogue Scale,VAS)、术后发热、术后住院时间、住院费用差异均无显著性(P>0.05)。结论肥胖患者行TU-LESS加一个操作孔的两孔腹腔镜子宫肌瘤剔除术安全、可行。
基金Supported by National Natural Science Foundation of China(Grant Nos.50576024 and 51076013)
文摘The startup process of a thermoacoustic engine is a self-excited oscillation process generated in inhomogeneous acoustic media.To reveal these coupling relations between various influential factors is an important task of basic research on thermoacoustics.In this paper thermoacoustic engines are regarded as thermoacoustic oscillators consisting of the active network and the passive network.Accordingly,the two-port Y-parameter for relevant component is derived,and standing wave and traveling wave thermoacoustic engine are described by the negative-resistance and feedback model,respectively.The relevant two-port network topology is given as well.The startup criteria for thermoacoustic oscillators are obtained by using Nyquist instability criterion.The model prediction of startup parameters,particularly,startup frequency and mode characteristic are in agreement with that of experimental results reported in the literature.Moreover,with topological graphs it is verified that standing wave engines would start up in a negative-resistance state and there would exist high frequency modes in thermoacoustic-Stirling engines.By investigating into the frequency response of thermoacoustic system,this method proposed can achieve such an objective that these effects of operating and structural parameters of engine on startup modes and startup temperature can be revealed in an analytical way.Thus this approach to test and check thermal stability can be provided in a design phase,instead of using empirical frequency to design thermoacoustic systems.
