Objectives: To assess respiratory elastance and resistive properties in patients with autoimmune liver disorders using the passive relaxation expiration technique and compare findings to a group of patients with non-a...Objectives: To assess respiratory elastance and resistive properties in patients with autoimmune liver disorders using the passive relaxation expiration technique and compare findings to a group of patients with non-autoimmune liver disease and control subjects. These findings were then related to control of ventilation and gas exchange. A secondary objective was to assess respiratory muscle strength and gas exchange and their relation to respiratory mechanics. Methods: Measurements included respiratory elastance and resistance using the passive relaxation method. Pulmonary function, gas exchange and control of ventilation were assessed using standard methods. Results: a) Compared to control subjects, Ers in patients with liver disease was on average 50% greater than in controls;b) mean respiratory resistance, expressed as the respiratory constants, K<sub>1</sub> and K<sub>2</sub> in the Rohrer relationship, Pao/V’ = K<sub>1</sub> + K<sub>2</sub>V’, was not different from control resistance;c) mean maximal inspiratory and maximal expiratory pressures averaged 36% and 55% of their respective control values;d) inspiratory occlusion pressure in 0.1 sec (P<sub>0.1</sub>) was increased and negatively associated with FVC;and e) increases in P<sub>0.1</sub>, mean inspiratory flow (Vt/Ti) and presence of respiratory alkalosis confirmed the increase in ventilatory drive. Despite inspiratory muscle weakness in patients, P<sub>0.1</sub>/Pimax averaged 5-fold higher than in control subjects. Conclusions: Despite inspiratory muscle weakness and a V’<sub>E</sub> similar to that in normal subjects, central drive is increased in patients with chronic liver disease. The increase in ventilatory drive is related to smaller lung volumes and weakly associated with increase in respiratory elastance. Findings confirm that P<sub>0.1</sub> is a reliable measure of central drive and is an approach that can be used in the evaluation of control of ventilation in patients with chronic liver disease.展开更多
Three kinds of full compositional distribution （from 0 to 100wt%W） W/Cu FGMs （functionally graded materials） with high density is fabricated by resistance sintering under ultra-high pressure. Microstructure analys...Three kinds of full compositional distribution （from 0 to 100wt%W） W/Cu FGMs （functionally graded materials） with high density is fabricated by resistance sintering under ultra-high pressure. Microstructure analysis showed that the good grading composition of all FGMs has been obtained. The sintering mechanism of W is mainly solid state sintering. Thermal shock test in air demonstrated that the grading at the interface between W and Cu is effective for the reduction of thermal stress, but obvious transver- se and vertical cracks occur in the pure W layer. The oxidation of the W60Cu40 layer and the W40Cu60 layer is heavier than that of the other layers.展开更多
With the high-quality development of urban buildings,higher requirements are come up with for lateral bearing capacity of laterally loaded piles.Consequently,a more accurate analysis to predict the lateral response of...With the high-quality development of urban buildings,higher requirements are come up with for lateral bearing capacity of laterally loaded piles.Consequently,a more accurate analysis to predict the lateral response of the pile within an allowable displacement is an important issue.However,the current p-y curve methods cannot fully take into account the pile-soil interaction,which will lead to a large calculation difference.In this paper,a new analytical p-y curve is established and a finite difference method for determining the lateral response of pile is proposed,which can consider the separation effect of pile-soil interface and the coefficient of circumferential friction resistance.In particular,an analytical expression is developed to determine the compressive soil pressure by dividing the compressive soil pressure into two parts:initial compressive soil pressure and increment of compressive soil pressure.In addition,the relationship between compressive soil pressure and horizontal displacement of the pile is established based on the reasonable assumption.The correctness of the proposed method is verified through four examples.Based on the verified method,a parametric analysis is also conducted to investigate the influences of factors on lateral response of the pile,including internal friction angle,pile length and elastic modulus of pile.展开更多
目的 探讨单双肺气道压差值(airway pressure differences between one lung and two lung ventilation,ΔP)指导双腔气管导管(double lumen tube,DLT)插管定位的效率及肺隔离效果。方法 选取2021年11月至2022年10月北京协和医院胸外科...目的 探讨单双肺气道压差值(airway pressure differences between one lung and two lung ventilation,ΔP)指导双腔气管导管(double lumen tube,DLT)插管定位的效率及肺隔离效果。方法 选取2021年11月至2022年10月北京协和医院胸外科拟在单肺通气下手术的患者396例,患者随机分为纤维支气管镜(fiber optical bronchoscopy,FOB)组和ΔP组,每组198例,FOB组采用FOB定位DLT,ΔP组采用ΔP定位DLT。比较两组侧卧位后DLT调整时间、DLT插管时间、SpO_(2)及肺塌陷效果满意度。结果 396例患者中,男203例,女193例,年龄36~69岁,平均(56.8±4.8)岁。ΔP组侧卧位后DLT调整时间短于FOB组[(37.73±14.06)s比(51.76±15.74)s],差异有统计学意义(P<0.05);两组DLT插管时间、SpO_(2)、肺塌陷效果满意度的比较,差异均无统计学意义(P>0.05)。结论 ΔP具有操作时间短、较高DLT定位成功率和较好单肺通气肺塌陷效果等优势,尤其在FOB缺少时,ΔP可作为DLT插管定位的新方法。展开更多
文摘Objectives: To assess respiratory elastance and resistive properties in patients with autoimmune liver disorders using the passive relaxation expiration technique and compare findings to a group of patients with non-autoimmune liver disease and control subjects. These findings were then related to control of ventilation and gas exchange. A secondary objective was to assess respiratory muscle strength and gas exchange and their relation to respiratory mechanics. Methods: Measurements included respiratory elastance and resistance using the passive relaxation method. Pulmonary function, gas exchange and control of ventilation were assessed using standard methods. Results: a) Compared to control subjects, Ers in patients with liver disease was on average 50% greater than in controls;b) mean respiratory resistance, expressed as the respiratory constants, K<sub>1</sub> and K<sub>2</sub> in the Rohrer relationship, Pao/V’ = K<sub>1</sub> + K<sub>2</sub>V’, was not different from control resistance;c) mean maximal inspiratory and maximal expiratory pressures averaged 36% and 55% of their respective control values;d) inspiratory occlusion pressure in 0.1 sec (P<sub>0.1</sub>) was increased and negatively associated with FVC;and e) increases in P<sub>0.1</sub>, mean inspiratory flow (Vt/Ti) and presence of respiratory alkalosis confirmed the increase in ventilatory drive. Despite inspiratory muscle weakness in patients, P<sub>0.1</sub>/Pimax averaged 5-fold higher than in control subjects. Conclusions: Despite inspiratory muscle weakness and a V’<sub>E</sub> similar to that in normal subjects, central drive is increased in patients with chronic liver disease. The increase in ventilatory drive is related to smaller lung volumes and weakly associated with increase in respiratory elastance. Findings confirm that P<sub>0.1</sub> is a reliable measure of central drive and is an approach that can be used in the evaluation of control of ventilation in patients with chronic liver disease.
基金This work was financially supported by the National Natural Science Foundation of China (No.50301001)
文摘Three kinds of full compositional distribution （from 0 to 100wt%W） W/Cu FGMs （functionally graded materials） with high density is fabricated by resistance sintering under ultra-high pressure. Microstructure analysis showed that the good grading composition of all FGMs has been obtained. The sintering mechanism of W is mainly solid state sintering. Thermal shock test in air demonstrated that the grading at the interface between W and Cu is effective for the reduction of thermal stress, but obvious transver- se and vertical cracks occur in the pure W layer. The oxidation of the W60Cu40 layer and the W40Cu60 layer is heavier than that of the other layers.
基金Project(52068004)supported by the National Natural Science Foundation of ChinaProject(2018JJA160134)supported by the Natural Science Foundation of Guangxi Province,ChinaProject(AB19245018)supported by Key Research Projects of Guangxi Province,China。
文摘With the high-quality development of urban buildings,higher requirements are come up with for lateral bearing capacity of laterally loaded piles.Consequently,a more accurate analysis to predict the lateral response of the pile within an allowable displacement is an important issue.However,the current p-y curve methods cannot fully take into account the pile-soil interaction,which will lead to a large calculation difference.In this paper,a new analytical p-y curve is established and a finite difference method for determining the lateral response of pile is proposed,which can consider the separation effect of pile-soil interface and the coefficient of circumferential friction resistance.In particular,an analytical expression is developed to determine the compressive soil pressure by dividing the compressive soil pressure into two parts:initial compressive soil pressure and increment of compressive soil pressure.In addition,the relationship between compressive soil pressure and horizontal displacement of the pile is established based on the reasonable assumption.The correctness of the proposed method is verified through four examples.Based on the verified method,a parametric analysis is also conducted to investigate the influences of factors on lateral response of the pile,including internal friction angle,pile length and elastic modulus of pile.
文摘目的 探讨单双肺气道压差值(airway pressure differences between one lung and two lung ventilation,ΔP)指导双腔气管导管(double lumen tube,DLT)插管定位的效率及肺隔离效果。方法 选取2021年11月至2022年10月北京协和医院胸外科拟在单肺通气下手术的患者396例,患者随机分为纤维支气管镜(fiber optical bronchoscopy,FOB)组和ΔP组,每组198例,FOB组采用FOB定位DLT,ΔP组采用ΔP定位DLT。比较两组侧卧位后DLT调整时间、DLT插管时间、SpO_(2)及肺塌陷效果满意度。结果 396例患者中,男203例,女193例,年龄36~69岁,平均(56.8±4.8)岁。ΔP组侧卧位后DLT调整时间短于FOB组[(37.73±14.06)s比(51.76±15.74)s],差异有统计学意义(P<0.05);两组DLT插管时间、SpO_(2)、肺塌陷效果满意度的比较,差异均无统计学意义(P>0.05)。结论 ΔP具有操作时间短、较高DLT定位成功率和较好单肺通气肺塌陷效果等优势,尤其在FOB缺少时,ΔP可作为DLT插管定位的新方法。
