Objective To retrospectively identify risk factors and the prognosis for new-onset atrial fibrillation (AF)after implantation of dual-chamber pacemakers in elderly patients.Methods Consecutive patients aged >65year...Objective To retrospectively identify risk factors and the prognosis for new-onset atrial fibrillation (AF)after implantation of dual-chamber pacemakers in elderly patients.Methods Consecutive patients aged >65years who underwent their first implantation of a dual-chamber permanent pacemaker in Beijing Anzhen Hospital from October 2013to May 2016were enrolled.Their complete program- ming and follow-up data were recorded.Follow-up end points included new-onset AF and major adverse cardiovascular and cerebrovascular events.Restdts Altogether,322patients were enrolled,with new-onset AF observed in 79(24.5%)during their follow-up.Multivariable analysis identified four independent predictors of new-onset AF in elderly patients after pacemaker implantation:hypertension (HR =3.040, 95%CI:1.09-3.05,P =0.00),age (HR =1.966,95%CI:1.57-3.68,P =0.01);left atrial enlargement (HR =1.645,95%CI:1.05-1.25,P = 0.03);high ventricular pacing rate (HR =1.137,95%CI:1.01-1.06,P =0.01).Univariable analysis indicated that the CHA2DS2-VASc score was also a risk factor for AF (HR =1.368,95%CI:1.178-1.589,P =0.002),whereas multivariable regression analysis did not. Kaplan-Meier survival analysis showed that the risk for ischemic stroke was significantly higher in the new-onset AF group than in the non-AF group (P <0.05).Conclusion Hypertension,age,left atrial enlargement,and high ventricular pacing rate were independent predictors of new-onset AF in elderly patients after implantation of a permanent pacemaker.New-onset AF increased the risk for ischemic stroke.展开更多
In this paper three types of dual- chamber shock- struts are considered in dynamic analyses of landing-gear behavior during impact and taxi. Their dynamic characteristics are compared with each other according to calc...In this paper three types of dual- chamber shock- struts are considered in dynamic analyses of landing-gear behavior during impact and taxi. Their dynamic characteristics are compared with each other according to calculation results, and some conclusions are presented.It is very helpful for selecting a suitable type of dual-chamber shock-strut in landing-gear design.展开更多
Cor triatriatum dextrum is an extremely rare congenital heart abnormality in which the right atrium is separatedinto two chambers by a persistent fibrous membrane. A transvenous approach to place a dual-chamber pacema...Cor triatriatum dextrum is an extremely rare congenital heart abnormality in which the right atrium is separatedinto two chambers by a persistent fibrous membrane. A transvenous approach to place a dual-chamber pacemaker in such patients is technically challenging. We report the first case of a transvenous permanent pacemaker placement in a patient with cor triatriatum dextrum. An 87-year-old woman was diagnosed with paroxysmal atrial fibrillation. She was accidentally found to have cor triatriatum dextrum during the transesophageal echocardiography(TEE) prior to cardioversion. Later during her hospital stay, it was indicated to place a permanant pacemaker due to high grade atrioventricular block. After thorough reviewing TEE imagings, a transvenous catheter-based approach was decided feasible. Patient successfully received a dual chamber pacemaker through left subclavian venous approach. Furthermore in our case, using specially designed pacemaker leads and cautious intra-procedural maneuvering under fluoroscopic guidance ensured procedural success. In summary, a thorough pre-operative evaluation with transesophageal echocardiography is critical for the planning and eventual success of the transvenous placement of rightsided leads.展开更多
This paper compared the degradation efficiency of sludge organic matters and electric-production by two typical microbial fuel cells——dual-chamber microbial fuel cell(DMFC)and single chamber air cathode microbial fu...This paper compared the degradation efficiency of sludge organic matters and electric-production by two typical microbial fuel cells——dual-chamber microbial fuel cell(DMFC)and single chamber air cathode microbial fuel cell(SAMFC),and the variations of sludge protein,polysaccharide and ammonia nitrogen within the systems were also investigated.The results showed that the concentration of sludge soluble chemical oxygen demand,protein and carbohydrate of DMFC are higher than these of SAMFC during the systems operation,while DMFC can achieve a better ammonia nitrogen removal than SAMFC.Under the same operation condition,the stable voltage output of DMFC and SAMFC is 0.61 V and 0.37 V;the maximum power density of DMFC and SAMFC is 2.79 W/m3and 1.25 W/m3;TCOD removal efficiency of DMFC and SAMFC is 34.14%and 28.63%for 12 d,respectively.Meanwhile,DMFC has a higher coulomb efficiency than SAMFC,but both are less than5%.The results showed that DMFC present a better performance on sludge degradation and electric-production.展开更多
In this study, a novel generator for the single-effect LiBr-H2O absorption chiller using solar energy was investigated. A dual-chamber vortex generator (DCVG) consisted of a lower chamber and an upper chamber. The hot...In this study, a novel generator for the single-effect LiBr-H2O absorption chiller using solar energy was investigated. A dual-chamber vortex generator (DCVG) consisted of a lower chamber and an upper chamber. The hot weak LiBr-H2O liquid entered the lower chamber tangentially through a small nozzle to create a strong vortex flow. Due to the rotating flow, the pressure was reduced toward the central portion of the lower chamber. Experiments were conducted under different solution flow rates and temperatures. The experimental results showed that the lower pressure developed in the lower chamber could reduce the saturated temperature and help the evaporation in the generator that is more heat could be utilized to generate more refrigerant vapor. When the inlet temperature was 90°C, the COP of a solar absorption chiller using the DCVG could reach 0.83, which was higher than of the conventional absorption chiller by 22%.展开更多
文摘Objective To retrospectively identify risk factors and the prognosis for new-onset atrial fibrillation (AF)after implantation of dual-chamber pacemakers in elderly patients.Methods Consecutive patients aged >65years who underwent their first implantation of a dual-chamber permanent pacemaker in Beijing Anzhen Hospital from October 2013to May 2016were enrolled.Their complete program- ming and follow-up data were recorded.Follow-up end points included new-onset AF and major adverse cardiovascular and cerebrovascular events.Restdts Altogether,322patients were enrolled,with new-onset AF observed in 79(24.5%)during their follow-up.Multivariable analysis identified four independent predictors of new-onset AF in elderly patients after pacemaker implantation:hypertension (HR =3.040, 95%CI:1.09-3.05,P =0.00),age (HR =1.966,95%CI:1.57-3.68,P =0.01);left atrial enlargement (HR =1.645,95%CI:1.05-1.25,P = 0.03);high ventricular pacing rate (HR =1.137,95%CI:1.01-1.06,P =0.01).Univariable analysis indicated that the CHA2DS2-VASc score was also a risk factor for AF (HR =1.368,95%CI:1.178-1.589,P =0.002),whereas multivariable regression analysis did not. Kaplan-Meier survival analysis showed that the risk for ischemic stroke was significantly higher in the new-onset AF group than in the non-AF group (P <0.05).Conclusion Hypertension,age,left atrial enlargement,and high ventricular pacing rate were independent predictors of new-onset AF in elderly patients after implantation of a permanent pacemaker.New-onset AF increased the risk for ischemic stroke.
文摘In this paper three types of dual- chamber shock- struts are considered in dynamic analyses of landing-gear behavior during impact and taxi. Their dynamic characteristics are compared with each other according to calculation results, and some conclusions are presented.It is very helpful for selecting a suitable type of dual-chamber shock-strut in landing-gear design.
文摘Cor triatriatum dextrum is an extremely rare congenital heart abnormality in which the right atrium is separatedinto two chambers by a persistent fibrous membrane. A transvenous approach to place a dual-chamber pacemaker in such patients is technically challenging. We report the first case of a transvenous permanent pacemaker placement in a patient with cor triatriatum dextrum. An 87-year-old woman was diagnosed with paroxysmal atrial fibrillation. She was accidentally found to have cor triatriatum dextrum during the transesophageal echocardiography(TEE) prior to cardioversion. Later during her hospital stay, it was indicated to place a permanant pacemaker due to high grade atrioventricular block. After thorough reviewing TEE imagings, a transvenous catheter-based approach was decided feasible. Patient successfully received a dual chamber pacemaker through left subclavian venous approach. Furthermore in our case, using specially designed pacemaker leads and cautious intra-procedural maneuvering under fluoroscopic guidance ensured procedural success. In summary, a thorough pre-operative evaluation with transesophageal echocardiography is critical for the planning and eventual success of the transvenous placement of rightsided leads.
基金Sponsored by the National Natural Science Key Foundation of China(Grant No.51206036)the Fundamental Research Funds for the Central Universities(Grant No.HIT.NSRIF.201192)+1 种基金State Key Laboratory of Urban Water Resource and EnvironmentHarbin Institute of Technology(Grant No.2013DX04)
文摘This paper compared the degradation efficiency of sludge organic matters and electric-production by two typical microbial fuel cells——dual-chamber microbial fuel cell(DMFC)and single chamber air cathode microbial fuel cell(SAMFC),and the variations of sludge protein,polysaccharide and ammonia nitrogen within the systems were also investigated.The results showed that the concentration of sludge soluble chemical oxygen demand,protein and carbohydrate of DMFC are higher than these of SAMFC during the systems operation,while DMFC can achieve a better ammonia nitrogen removal than SAMFC.Under the same operation condition,the stable voltage output of DMFC and SAMFC is 0.61 V and 0.37 V;the maximum power density of DMFC and SAMFC is 2.79 W/m3and 1.25 W/m3;TCOD removal efficiency of DMFC and SAMFC is 34.14%and 28.63%for 12 d,respectively.Meanwhile,DMFC has a higher coulomb efficiency than SAMFC,but both are less than5%.The results showed that DMFC present a better performance on sludge degradation and electric-production.
基金Supported by the Opening Foundation of Beijing Municipality
文摘In this study, a novel generator for the single-effect LiBr-H2O absorption chiller using solar energy was investigated. A dual-chamber vortex generator (DCVG) consisted of a lower chamber and an upper chamber. The hot weak LiBr-H2O liquid entered the lower chamber tangentially through a small nozzle to create a strong vortex flow. Due to the rotating flow, the pressure was reduced toward the central portion of the lower chamber. Experiments were conducted under different solution flow rates and temperatures. The experimental results showed that the lower pressure developed in the lower chamber could reduce the saturated temperature and help the evaporation in the generator that is more heat could be utilized to generate more refrigerant vapor. When the inlet temperature was 90°C, the COP of a solar absorption chiller using the DCVG could reach 0.83, which was higher than of the conventional absorption chiller by 22%.
