The efficacy of the oxygen reduction reaction(ORR) in fuel cells can be significantly enhanced by optimizing cobalt-based catalysts,which provide a more stable alternative to iron-based catalysts.However,their perform...The efficacy of the oxygen reduction reaction(ORR) in fuel cells can be significantly enhanced by optimizing cobalt-based catalysts,which provide a more stable alternative to iron-based catalysts.However,their performance is often impeded by weak adsorption of oxygen species,leading to a 2e^(-)pathway that negatively affects fuel cell discharge efficiency.Here,we engineered a high-density cobalt active center catalyst,coordinated with nitrogen and sulfur atoms on a porous carbon substrate.Both experimental and theoretical analyses highlighted the role of sulfur atoms as electron donors,disrupting the charge symmetry of the original Co active center and promoting enhanced interaction with Co 3d orbitals.This modification improves the adsorption of oxygen and reaction intermediates during ORR,significantly reducing the production of hydrogen peroxide(H_(2)O_(2)).Remarkably,the optimized catalyst demonstrated superior fuel cell performance,with peak power densities of 1.32 W cm^(-2) in oxygen and 0.61 W cm^(-2) in air environments,respectively.A significant decrease in H_(2)O_(2) by-product accumulation was observed during the reaction process,reducing catalyst and membrane damage and consequently improving fuel cell durability.This study emphasizes the critical role of coordination symmetry in Co/N/C catalysts and proposes an effective strategy to enhance fuel cell performance.展开更多
BACKGROUND： Few studies have reported the effects of early tracheotomy in acute severe asthmatic patients. We report two patients with acute severe asthma who were successfully treated with early tracheotomy. METHOD...BACKGROUND： Few studies have reported the effects of early tracheotomy in acute severe asthmatic patients. We report two patients with acute severe asthma who were successfully treated with early tracheotomy. METHODS：The two patients with acute severe asthma were retrospectively reviewed. They had been treated at the Department of Emergency and Critical Care, Renji Hospital, Shanghai Jiaotong University School of Medicine. RESULTS： They developed progressively hypercapnia and severe acidosis, and were not improved after conventional therapies. Early tracheotomy after mechanical ventilation decreased airway resistance and work of breathing, and corrected hypercapnia and acidosis. Adequate gas exchange was maintained after tracheotomy. The two patients were subsequently weaned from mechanical ventilation and discharged. CONCLUSION：Early tracheotomy could be a valuable approach in certain patients with severe asthma.展开更多
Objective To investigate the relationship between CRP, plasminogen activator inhibitor type 1 （PAI-1） levels, PAI-1 gene promoter 4G/5G polymorphism and the type of acute myocardial infarction （ST elevation myocard...Objective To investigate the relationship between CRP, plasminogen activator inhibitor type 1 （PAI-1） levels, PAI-1 gene promoter 4G/5G polymorphism and the type of acute myocardial infarction （ST elevation myocardial infarction, STEMI vs the non-ST elevation Myocardial infarction, NSTEMI）. Methods One hundred seventy-six consecutive patients with AMI were included for the study, of whom 60 had STEMI and 56 had NSTEMI, and 60 adults without cardiovascular and cerebrovascular disease were selected as controls. Blood samples were obtained from patients within 6 h of AMI and the plasma PAI-1, CRP, and the gene polymorphism were measured. Results Plasma levels of PAI- 1 and CRP were higher in AMI groups, compared those in the control group, and plasma levels of PAI-1 were significantly higher in patients with STEMI compared to those with NSTEMI （80.12ng/ml VS.73.01ng/ml, P 〈0.01）, while CRP levels were not significantly different between patient with STEMI and NSTEMI （3.87 ± 0.79 mg/ml VS.4.01 ±0.69mg/ml, P〉0.05）. PAI-1 levels presented a significant correlation with CRP levels in the NSTEMI subjects. However, PAI-1 and CRP levels could explain the lack of a significant relationship between them in control and STEMI subjects.The frequencies of 4G/4G genotype in the AMI group were higher than those in the control group and higher in patient with STEMI than in patient with NSTEMI. Plasma levels of PAI-1 in subjects with 4G/4G genotype were significantly increased as compared to those in subjects with 4G/5G and 5G/5G genotype. Conclusions Plasma PAI-1 levels were associated with different myocardial infarction type, and PAI-1 promoter 4G/5G polymorphisms and CRP may be related to plasma PAI-1 levels展开更多
基金financially National Natural Science Foundation of China (22288102, 22172134, U1932201, U2032202)Science and Technology Planning Project of Fujian Province (2022H0002)support from the EPSRC (EP/W03784X/1)。
文摘The efficacy of the oxygen reduction reaction(ORR) in fuel cells can be significantly enhanced by optimizing cobalt-based catalysts,which provide a more stable alternative to iron-based catalysts.However,their performance is often impeded by weak adsorption of oxygen species,leading to a 2e^(-)pathway that negatively affects fuel cell discharge efficiency.Here,we engineered a high-density cobalt active center catalyst,coordinated with nitrogen and sulfur atoms on a porous carbon substrate.Both experimental and theoretical analyses highlighted the role of sulfur atoms as electron donors,disrupting the charge symmetry of the original Co active center and promoting enhanced interaction with Co 3d orbitals.This modification improves the adsorption of oxygen and reaction intermediates during ORR,significantly reducing the production of hydrogen peroxide(H_(2)O_(2)).Remarkably,the optimized catalyst demonstrated superior fuel cell performance,with peak power densities of 1.32 W cm^(-2) in oxygen and 0.61 W cm^(-2) in air environments,respectively.A significant decrease in H_(2)O_(2) by-product accumulation was observed during the reaction process,reducing catalyst and membrane damage and consequently improving fuel cell durability.This study emphasizes the critical role of coordination symmetry in Co/N/C catalysts and proposes an effective strategy to enhance fuel cell performance.
文摘BACKGROUND： Few studies have reported the effects of early tracheotomy in acute severe asthmatic patients. We report two patients with acute severe asthma who were successfully treated with early tracheotomy. METHODS：The two patients with acute severe asthma were retrospectively reviewed. They had been treated at the Department of Emergency and Critical Care, Renji Hospital, Shanghai Jiaotong University School of Medicine. RESULTS： They developed progressively hypercapnia and severe acidosis, and were not improved after conventional therapies. Early tracheotomy after mechanical ventilation decreased airway resistance and work of breathing, and corrected hypercapnia and acidosis. Adequate gas exchange was maintained after tracheotomy. The two patients were subsequently weaned from mechanical ventilation and discharged. CONCLUSION：Early tracheotomy could be a valuable approach in certain patients with severe asthma.
文摘Objective To investigate the relationship between CRP, plasminogen activator inhibitor type 1 （PAI-1） levels, PAI-1 gene promoter 4G/5G polymorphism and the type of acute myocardial infarction （ST elevation myocardial infarction, STEMI vs the non-ST elevation Myocardial infarction, NSTEMI）. Methods One hundred seventy-six consecutive patients with AMI were included for the study, of whom 60 had STEMI and 56 had NSTEMI, and 60 adults without cardiovascular and cerebrovascular disease were selected as controls. Blood samples were obtained from patients within 6 h of AMI and the plasma PAI-1, CRP, and the gene polymorphism were measured. Results Plasma levels of PAI- 1 and CRP were higher in AMI groups, compared those in the control group, and plasma levels of PAI-1 were significantly higher in patients with STEMI compared to those with NSTEMI （80.12ng/ml VS.73.01ng/ml, P 〈0.01）, while CRP levels were not significantly different between patient with STEMI and NSTEMI （3.87 ± 0.79 mg/ml VS.4.01 ±0.69mg/ml, P〉0.05）. PAI-1 levels presented a significant correlation with CRP levels in the NSTEMI subjects. However, PAI-1 and CRP levels could explain the lack of a significant relationship between them in control and STEMI subjects.The frequencies of 4G/4G genotype in the AMI group were higher than those in the control group and higher in patient with STEMI than in patient with NSTEMI. Plasma levels of PAI-1 in subjects with 4G/4G genotype were significantly increased as compared to those in subjects with 4G/5G and 5G/5G genotype. Conclusions Plasma PAI-1 levels were associated with different myocardial infarction type, and PAI-1 promoter 4G/5G polymorphisms and CRP may be related to plasma PAI-1 levels
