There is limited information about the factors that affect the power generation of single-chamber microbial fuel cells(MFCs) using soil organic matter as a fuel source. We examined the effect of soil and water depths,...There is limited information about the factors that affect the power generation of single-chamber microbial fuel cells(MFCs) using soil organic matter as a fuel source. We examined the effect of soil and water depths, and temperature on the performance of soil MFCs with anode being embedded in the flooded soil and cathode in the overlaying water. Results showed that the MFC with 5 cm deep soil and 3 cm overlaying water exhibited the highest open circuit voltage of 562 mV and a power density of 0.72 mW m-2. The ohmic resistance increased with more soil and water. The polarization resistance of cathode increased with more soil while that of anode increased with more water. During the 30 d operation, the cell voltage positively correlated with temperature and reached a maximum of 162 mV with a 500 ? external load. After the operation, the bacterial 16S rRNA gene from the soil and anode was sequenced. The bacteria in the soil were more diverse than those adhere to the anode where the bacteria were mainly affiliated to Escherichia coli and Deltaproteobacteria. In summary, the two bacterial groups may generate electricity and the electrical properties were affected by temperature and the depth of soil and water.展开更多
针对以海藻酸钠为代表的传统固定化材料制备的微藻胶球传质性能较差,对水中总磷去除率低的问题,开发了纳米Al2O3-海藻酸钠联合固定化小球藻胶球,研究了初始总磷浓度、胶球粒径和粒数对联合固定化小球藻去除总磷的影响。结果表明:纳米Al...针对以海藻酸钠为代表的传统固定化材料制备的微藻胶球传质性能较差,对水中总磷去除率低的问题,开发了纳米Al2O3-海藻酸钠联合固定化小球藻胶球,研究了初始总磷浓度、胶球粒径和粒数对联合固定化小球藻去除总磷的影响。结果表明:纳米Al2O3增加了固定化小球藻胶球的比表面积,促进了小球藻对水中总磷的去除,总磷去除率随着胶球加入量的增加和胶球粒径的减小而提高。纳米Al2O3-海藻酸钠联合固定化小球藻胶球的最优制备方案如下:将0.15 g纳米Al2O3加入到30 m L浓度为1.8%海藻酸钠溶液中,然后再加入小球藻至藻细胞密度为2×106cell/m L,交联CaCl2浓度为1%。胶球重复使用3次时总磷去除率仍达到77.51%。展开更多
Background Transcatheter aortic valve implantation （TAVI） has emerged as the treatment choice for non-operable patients with severe symptomatic aortic stenosis （AS） and may be a good alternative to surgery for tho...Background Transcatheter aortic valve implantation （TAVI） has emerged as the treatment choice for non-operable patients with severe symptomatic aortic stenosis （AS） and may be a good alternative to surgery for those at very high or prohibitive surgical risk. We performed a meta-analysis to evaluate the comparative benefits of TAVI versus surgical aortic valve replacement （SAVR） in patients with severe AS. Methods A comprehensive literature search of PubMed, Embase, ScienceDirect and Cochrane Central Register of Codtrolled trials was performed, and randomized trials as well as cohort studies with propensity score analysis were included. Results One randomized trial （n=699） and six retrospective cohort studies （n=781） were selected for meta-analysis. Mortality at 30-day and 1-year follow-up was comparable between TAVI and SAVR. Despite similar incidences of stroke, myocardial infarction, re-operation for bleeding, and renal failure requiring dialysis, TAVI was associated with a lower occurrence rate of new-onset atrial fibrillation （OR 0.51,95% CI 0.33-0.78） and shorter procedural time （mean difference -67.50 minutes, 95% CI -87.20 to -47.81 minutes）. Post-operative aortic regurgitation and permanent pacemaker implantation were more common in patients after TAVI than in those with SAVR （OR 5.53, 95% CI 3.41-8.97; OR 1.71, 95% CI 1.02-2.84, respectively）. Conclusion In patients with severe symptomatic AS, TAVI and SAVR did not differ with respect to short- and mid-term survival, but the incidence of permanent pacemaker implantation and post-procedural aortic regurgitation remain relatively high after TAVI.展开更多
Objective To determine whether the prosthesis-patient mismatch has a deleterious impact on survival after mitral valve replacement.Data sources A comprehensive literature search of PubMed,Embase,and ScienceDirect was ...Objective To determine whether the prosthesis-patient mismatch has a deleterious impact on survival after mitral valve replacement.Data sources A comprehensive literature search of PubMed,Embase,and ScienceDirect was carried out.References and cited papers of relevant articles were also checked.Study selection All articles published after January 1980 was initially considered.Non-English and non-human studies,case reports,and reviews were excluded from the initial search.References and cited papers of relevant articles were also checked.Results A total of 8 retrospective cohort studies were identified for this review.The overall incidence of prosthesis-patient mismatch （〈1.3 to 〈1.2 cm2/m2） after mitral valve replacement ranged from 3.7% to 85.9% （moderate prosthesis-patient mismatch （0.9 to 1.2 cm2/m2） in 37.4% to 69.5%,severe prosthesis-patient mismatch （〈0.9 cm2/m2） in 8.7% to 16.4%）.Four studies demonstrated an association of prosthesis-patient mismatch with reduced long-term survival,but the other four studies found no significant deleterious impact of prosthesis-patient mismatch after mitral valve replacement.No definite conclusion could be derived from these conflicting results.Conclusions Current evidence is insufficient to derive a definite conclusion whether mitral prosthesis-patient mismatch affects long-term survival because of the biases and confounding factors that interfere with late clinical outcomes.Good-quality prospective studies are warranted to evaluate the impact of mitral prosthesis-patient mismatch after mitral valve replacement in the future.展开更多
基金Supported by the Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences(No.KZCXZ-EW-402)the Hundred Talents Program of Chinese Academy of Sciences+1 种基金the International S&T Cooperation Program of China(No.2011DFB91710)the China Postdoctoral Science Foundation(Nos.2011M500410 and 2012T50142)
文摘There is limited information about the factors that affect the power generation of single-chamber microbial fuel cells(MFCs) using soil organic matter as a fuel source. We examined the effect of soil and water depths, and temperature on the performance of soil MFCs with anode being embedded in the flooded soil and cathode in the overlaying water. Results showed that the MFC with 5 cm deep soil and 3 cm overlaying water exhibited the highest open circuit voltage of 562 mV and a power density of 0.72 mW m-2. The ohmic resistance increased with more soil and water. The polarization resistance of cathode increased with more soil while that of anode increased with more water. During the 30 d operation, the cell voltage positively correlated with temperature and reached a maximum of 162 mV with a 500 ? external load. After the operation, the bacterial 16S rRNA gene from the soil and anode was sequenced. The bacteria in the soil were more diverse than those adhere to the anode where the bacteria were mainly affiliated to Escherichia coli and Deltaproteobacteria. In summary, the two bacterial groups may generate electricity and the electrical properties were affected by temperature and the depth of soil and water.
文摘针对以海藻酸钠为代表的传统固定化材料制备的微藻胶球传质性能较差,对水中总磷去除率低的问题,开发了纳米Al2O3-海藻酸钠联合固定化小球藻胶球,研究了初始总磷浓度、胶球粒径和粒数对联合固定化小球藻去除总磷的影响。结果表明:纳米Al2O3增加了固定化小球藻胶球的比表面积,促进了小球藻对水中总磷的去除,总磷去除率随着胶球加入量的增加和胶球粒径的减小而提高。纳米Al2O3-海藻酸钠联合固定化小球藻胶球的最优制备方案如下:将0.15 g纳米Al2O3加入到30 m L浓度为1.8%海藻酸钠溶液中,然后再加入小球藻至藻细胞密度为2×106cell/m L,交联CaCl2浓度为1%。胶球重复使用3次时总磷去除率仍达到77.51%。
文摘Background Transcatheter aortic valve implantation （TAVI） has emerged as the treatment choice for non-operable patients with severe symptomatic aortic stenosis （AS） and may be a good alternative to surgery for those at very high or prohibitive surgical risk. We performed a meta-analysis to evaluate the comparative benefits of TAVI versus surgical aortic valve replacement （SAVR） in patients with severe AS. Methods A comprehensive literature search of PubMed, Embase, ScienceDirect and Cochrane Central Register of Codtrolled trials was performed, and randomized trials as well as cohort studies with propensity score analysis were included. Results One randomized trial （n=699） and six retrospective cohort studies （n=781） were selected for meta-analysis. Mortality at 30-day and 1-year follow-up was comparable between TAVI and SAVR. Despite similar incidences of stroke, myocardial infarction, re-operation for bleeding, and renal failure requiring dialysis, TAVI was associated with a lower occurrence rate of new-onset atrial fibrillation （OR 0.51,95% CI 0.33-0.78） and shorter procedural time （mean difference -67.50 minutes, 95% CI -87.20 to -47.81 minutes）. Post-operative aortic regurgitation and permanent pacemaker implantation were more common in patients after TAVI than in those with SAVR （OR 5.53, 95% CI 3.41-8.97; OR 1.71, 95% CI 1.02-2.84, respectively）. Conclusion In patients with severe symptomatic AS, TAVI and SAVR did not differ with respect to short- and mid-term survival, but the incidence of permanent pacemaker implantation and post-procedural aortic regurgitation remain relatively high after TAVI.
文摘Objective To determine whether the prosthesis-patient mismatch has a deleterious impact on survival after mitral valve replacement.Data sources A comprehensive literature search of PubMed,Embase,and ScienceDirect was carried out.References and cited papers of relevant articles were also checked.Study selection All articles published after January 1980 was initially considered.Non-English and non-human studies,case reports,and reviews were excluded from the initial search.References and cited papers of relevant articles were also checked.Results A total of 8 retrospective cohort studies were identified for this review.The overall incidence of prosthesis-patient mismatch （〈1.3 to 〈1.2 cm2/m2） after mitral valve replacement ranged from 3.7% to 85.9% （moderate prosthesis-patient mismatch （0.9 to 1.2 cm2/m2） in 37.4% to 69.5%,severe prosthesis-patient mismatch （〈0.9 cm2/m2） in 8.7% to 16.4%）.Four studies demonstrated an association of prosthesis-patient mismatch with reduced long-term survival,but the other four studies found no significant deleterious impact of prosthesis-patient mismatch after mitral valve replacement.No definite conclusion could be derived from these conflicting results.Conclusions Current evidence is insufficient to derive a definite conclusion whether mitral prosthesis-patient mismatch affects long-term survival because of the biases and confounding factors that interfere with late clinical outcomes.Good-quality prospective studies are warranted to evaluate the impact of mitral prosthesis-patient mismatch after mitral valve replacement in the future.
