BACKGROUND In critical care practice,difficult airway management poses a substantial challenge,necessitating urgent intervention to ensure patient safety and optimize outcomes.Extracorporeal membrane oxygenation(ECMO)...BACKGROUND In critical care practice,difficult airway management poses a substantial challenge,necessitating urgent intervention to ensure patient safety and optimize outcomes.Extracorporeal membrane oxygenation(ECMO)is a potential rescue tool in patients with severe airway compromise,although evidence of its efficacy and safety remains limited.AIM To review the local experience of using ECMO support in patients with difficult airway management.METHODS This retrospective case series study includes patients with difficult airway management who required ECMO support at a tertiary hospital in a Middle Eastern country.RESULTS Between 2016 and 2023,a total of 13 patients required ECMO support due to challenging airway patency in the operating room.Indications for ECMO encompassed various diagnoses,including tracheal stenosis,external tracheal compression,and subglottic stenosis.Surgical interventions such as tracheal resection and anastomosis often necessitated ECMO support to maintain adequate oxygenation and hemodynamic stability.The duration of ECMO support ranged from standby mode(ECMO implantation is readily available)to several days,with relatively infrequent complications observed.Despite the challenges encountered,most patients survived hospital discharge,highlighting the effectiveness of ECMO in managing difficult airways.CONCLUSION This study underscores the crucial role of ECMO as a life-saving intervention in selected cases of difficult airway management.Further research is warranted to refine the understanding of optimal management strategies and improve outcomes in this challenging patient population.展开更多
Magneli phase titanium sub-oxide conductive ceramic Tin O2n-1 was used as the support for Pt due to its excellent resistance to electrochemical oxidation, and Pt/Tin O2n-1 composites were prepared by the impregnation-...Magneli phase titanium sub-oxide conductive ceramic Tin O2n-1 was used as the support for Pt due to its excellent resistance to electrochemical oxidation, and Pt/Tin O2n-1 composites were prepared by the impregnation-reduction method. The electrochemical stability of Tin O2n-1 was investigated and the results show almost no change in the redox region after oxidation for 20 h at 1.2 V(vs NHE) in 0.5 mol/L H2SO4 aqueous solution. The catalytic activity and stability of the Pt/Tin O2n-1 toward the oxygen reduction reaction(ORR) in 0.5 mol/L H2SO4 solution were investigated through the accelerated aging tests(AAT), and the morphology of the catalysts before and after the AAT was observed by transmission electron microscopy. At the potential of 0.55 V(vs SCE), the specific kinetic current density of the ORR on the Pt/Tin O2n-1 is about 1.5 times that of the Pt/C. The LSV curves for the Pt/C shift negatively obviously with the half-wave potential shifting about 0.02 V after 8000 cycles AAT, while no obvious change takes place for the LSV curves for the Pt/Tin O2n-1. The Pt particles supported on the carbon aggregate obviously, while the morphology of the Pt supported on Tin O2n-1 remains almost unchanged, which contributes to the electrochemical surface area loss of Pt/C being about 2times that of the Pt/Tin O2n-1. The superior catalytic stability of Pt/Tin O2n-1 toward the ORR could be attributed to the excellent stability of the Tin O2n-1 and the electronic interaction between the metals and the support.展开更多
Au]Cel_xZrxO2 catalysts （x = 0-0.8） were prepared by a deposition-precipitation method using Cel_xZrxO2 nanoparticles as supports with variable Ce and Zr contents. Their structures were characterized by complimentar...Au]Cel_xZrxO2 catalysts （x = 0-0.8） were prepared by a deposition-precipitation method using Cel_xZrxO2 nanoparticles as supports with variable Ce and Zr contents. Their structures were characterized by complimentary means such as X-ray diffraction, Raman, scanning trans- mission electron microscopy and X-ray photoelectron spectroscopy （XPS）. These Au catalysts possessed similar sizes and crystalline phases of Cel_xZrzO2 supports as well as similar sizes and oxidation states of Au nanoparticles. The oxidation state of Au nanoparticles was dominated by Au~ especially in CO oxidation. Their activities were examined in CO oxidation at different temperatures in the range of 303-333 K. The CO oxidation rates normalized per Au atoms increased with the increasing Ce contents, and reached the maximum value over Au/CeO2. Such change was in parallel with the change in the oxygen storage capacity values, i.e. the amounts of active oxygen species on Au/Cel_zZrzO2 catalysts. The excellent correlation between the two properties of the catalysts suggests that the intrinsic support effects on the CO oxidation rates is related to the effects on the adsorption and activation of O2 on Au/Cel_xZrxO2 catalysts. Such understanding on the support effects may be useful for designing more active Au catalysts, for example, by tuning the redox properties of oxide supports.展开更多
In this work, the addition of praseodymium（Pr） into ceria as a mixed oxide support in a form of Ce（1-x）PrxO2（x = 0.01,0.025, 0.050, 0.075 and 0.10） was prepared using a co-precipitation method. The structural an...In this work, the addition of praseodymium（Pr） into ceria as a mixed oxide support in a form of Ce（1-x）PrxO2（x = 0.01,0.025, 0.050, 0.075 and 0.10） was prepared using a co-precipitation method. The structural and textural properties of the synthesized supports were characterized by X-ray diffraction（XRD）, N2 adsorption-desorption, Raman spectroscopy, H2-temperature programmed reduction（H2-TPR） and H2-chemisorption. Upon addition of Pr, XRD patterns and Raman spectra indicated an enlargement of ceria unit cell and the characteristics Raman broad peak at 570 cm^（-1） which was attributed to the existence of oxygen vacancies in the ceria lattice. This indicated that some Ce^（4＋） ions in ceria were replaced by larger Pr^（3＋） cations. To evidence the incorporation of Pr^（3＋） cations into ceria lattice,X-ray absorption near edge structure（XANES） was employed. The results showed that the oxidation states of Ce in mixed oxide supports were slightly lower than 4＋ while those of Pr were still the same as a precursor salt. Therefore, the incorporation of Pr^（3＋） into ceria lattice would lead to strain and unbalanced charge and result in oxygen vacancies. The reducibility of Ce（1-x）PrxO2 mixed oxide supports was investigated by H2-TPR and temperature-resolved X-ray absorption spectroscopy experiment under reduction conditions. XANES spectra of Ce L3 edges showed a lower surface reduction temperature（Ce^（4＋）to Ce^（3＋）） of Ce（0.925）Pr（0.075）O2 than that of CeO2 which agreed with H2-TPR results. H2-chemisorption indicated that Pr promoted the dispersion of the metal catalyst on the mixed oxide support and increased the adsorption site for CO. For WGS reaction, 1% Pd/mixed oxide support had higher WGS activity than 1%Pd/ceria. The increase of WGS activity was due to the increase of Pd dispersion on the support and the existence of oxygen vacancies produced from incorporation of Pr into the ceria lattice.展开更多
It has been generally recognised that the metal catalysts supported on oxide ceramic and non-oxide ceramic supports exhibit completely different characteristics as compared with the homogeneous ones. The na-ture of bo...It has been generally recognised that the metal catalysts supported on oxide ceramic and non-oxide ceramic supports exhibit completely different characteristics as compared with the homogeneous ones. The na-ture of bonding and interactions occurring at the metal / ceramic interfaces are believed to be of importancefor the characteristics of such catalysts. The recently developed microscopic theory of adhesion and wettingin metal/ ceramic systems is briefly presented here with the emphasis on the ionocovalent oxide ceramics.and its consequence on the understanding of the physical and chemical behaviours of supported metal cata-lysts is exploited.展开更多
BACKGROUND Very little is known about the role of extracorporeal membrane oxygenation(ECMO)for the management of patients undergoing major aortic surgery with particular reference to aortic dissection.AIM To review th...BACKGROUND Very little is known about the role of extracorporeal membrane oxygenation(ECMO)for the management of patients undergoing major aortic surgery with particular reference to aortic dissection.AIM To review the available literature to determine if there was any evidence.METHODS A systematic literature search through PubMed and EMBASE was undertaken according to specific key words.RESULTS The search resulted in 29 publications relevant to the subject:1 brief communication,1 surgical technique report,1 invited commentary,1 retrospective case review,1 observational study,4 retrospective reviews,13 case reports and 7 conference abstracts.A total of 194 patients were included in these publications of whom 77 survived.CONCLUSION Although there is no compelling evidence for or against the use of ECMO in major aortic surgery or dissection,it is enough to justify its use in this patient population despite current adverse attitude.展开更多
Introduction: World Health Organization announced on April 2009 a public health emergency of international concern caused by swine-origin influenza A(H1N1) virus. Acute respiratory distress syndrome(ARDS) has been rep...Introduction: World Health Organization announced on April 2009 a public health emergency of international concern caused by swine-origin influenza A(H1N1) virus. Acute respiratory distress syndrome(ARDS) has been reported to be the most devastating complications of this pathogen. Extracorporeal membrane oxygenator(ECMO) therapy for patients with H1N1 related ARDS has been described once all other therapeutic options have been exhausted. Here, we report the case of a child(German, male) with H1N1-associated fulminate respiratory and secondary hemodynamic deterioration who was rescued by initial emergent ECMO established through a dialysis catheter and subsequent switch to central cannulation following median sternotomy. This report highlights several important issues. First, it describes a successful use of a dialysis catheter for the establishment of a veno-venous ECMO in an emergency case by child. Second, it highlights the importance of a closely monitoring of clotting parameters during ECMOtherapy and third, if severe respiratory failure is complicated by cardiogenic shock, veno-atrial ECMO support via median sternotomy should be considered as a viable treatment option without further delay.展开更多
EHMO calculations and orbital analyses of fragment;;have been performed for the formation of oxygenates in Fischer-Tropsch synthesis on the butterfly model for four different metal (Ni,Ru,Rh,Pd) catalysts supported on...EHMO calculations and orbital analyses of fragment;;have been performed for the formation of oxygenates in Fischer-Tropsch synthesis on the butterfly model for four different metal (Ni,Ru,Rh,Pd) catalysts supported on SiO2.Calculations were made for the four processes,i.e.,CO-dissociation;Coupling of CO and H to produce CHO;Insertion of CO to M-CH3;insertion of CH2 to M-CH3 On the basis of comparing the degree of CO bonds activation and the energy barriers of the foregoing processes for these four catalysts,it is concluded that Ni/SiO2 can be used as the methanation catalyst.On Ru/SiO2 and Rh/SiO2 C2-oxygenated compound can be produced (acetaldehyde),especially Rh/SiO2 is the even better catalyst,and Pd/SiO2 is a methanol synthesis catalyst.展开更多
Porous carbon nanofibers (PCNFs) were prepared through electrospinning, pre-oxidation and carbonization with polyacrylonitrile (PAN) as carbon precursor and polymethyl methacrylate (PMMA), CaCO3 as pore-forming agents...Porous carbon nanofibers (PCNFs) were prepared through electrospinning, pre-oxidation and carbonization with polyacrylonitrile (PAN) as carbon precursor and polymethyl methacrylate (PMMA), CaCO3 as pore-forming agents. The structure, morphology, specific surface area and electrochemical performance of the carbon nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption/desorption method and electrochemical tests. Compared with PCNFs without CaCO3, PCNFs(CaCO3 1%) had higher specific surface area, better dispersion of Pt nanoparticles, and the particle size become smaller, which was corresponding with the results of electrochemical performance test. It could be seen in cyclic voltammetry (CV) and linear sweep voltammetry (LSV) test, ECSA of Pt/PCNFs (CaCO3 1%) attained 82 m2?g?1, while that of JM20 and Pt/PCNFs without CaCO3 were 77 m2?g?1 and 60 m2?g?1, respectively. These results revealed that CaCO3 as the second pore-forming agent can further increase the mesoporous number and specific surface area of nanofibers, and can improve the electrochemical properties of Pt catalyst as the support.展开更多
Gold catalysts supported on SiO2, TiO2, TiO2-SiO2, and ZrO2-SiO2 supports were prepared by impregnating each support with a basic solution of tetrachloroauric acid. X-ray diffraction （XRD）, transmission electron mic...Gold catalysts supported on SiO2, TiO2, TiO2-SiO2, and ZrO2-SiO2 supports were prepared by impregnating each support with a basic solution of tetrachloroauric acid. X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and X-ray photoelectron spectroscopy （XPS） techniques were used to characterize their structure and surface composition. The results indicated that the size of gold particles could be controlled to below 10 nm by this method of preparation. Washing gold catalysts with water could markedly enhance the dispersion of metallic gold particles on the surface, but it could not completely remove the chloride ions left on the surface. The catalytic performance of direct vapor-phase epoxidation of propylene using air as an oxidant over these catalysts was evaluated at atmospheric pressure. The selectivity to propylene oxide （PO） was found to vary with reaction time on the stream. At the reaction conditions of atmosphere pressure, temperature 325 ℃, feed gas ratio V（C3H6）/V（O2）= 1/2, and GHSV =6000h^-1, 17.9% PO selectivity with 0.9% propylene conversion were obtained at initial 10 min for Au/SiO2 catalyst. After reacting 60 min only 8.9% PO selectivity were detected, but the propylene conversion rises to 1.4% and the main product is transferred to acrolein （72% selectivity）. Washing Au/TiO2-SiO2 and Aa/ZrO2-SiO2 samples with magnesium citrate solution could markedly enhance the activity and PO selectivity because smaller gold particles were obtained.展开更多
Lung transplant is the standard of care for patients with end-stage lung disease refractory to medical management. There is currently a critical organ shortage for lung transplantation with only 17% of offered organs ...Lung transplant is the standard of care for patients with end-stage lung disease refractory to medical management. There is currently a critical organ shortage for lung transplantation with only 17% of offered organs being transplanted. Of those patients receiving a lung transplant, up to 25% will develop primary graft dysfunction, which is associated with an 8-fold increase in 30-d mortality. There are numerous mechanical lung assistance modalities that may be employed to help combat these challenges. We will discuss the use of mechanical lung assistance during lung transplantation, as a bridge to transplant, as a treatment for primary graft dysfunction, and finally as a means to remodel and evaluate organs deemed unsuitable for transplant, thus increasing the donor pool, improving survival to transplant, and improving overall patient survival.展开更多
Introduction: Extracorporeal Membrane Oxygenation (ECMO) is used in selected patient with cardiogenic and/or re- spiratory shock. We report our experience with standardized management protocols and the application of ...Introduction: Extracorporeal Membrane Oxygenation (ECMO) is used in selected patient with cardiogenic and/or re- spiratory shock. We report our experience with standardized management protocols and the application of the Qua- droxD oxygenator with a centrifugal pump to maximize end-organ recovery and improve survival. Methods: This is an Internal Review Board (IRB) approved, single institution retrospective study of end-organ recovery and survival in pa- tients who required ECMO for cardiogenic and/or respiratory shock between July 2010 and June 2011. Results: Sixteen patients (median age: 46 years) were initiated on either Veno-Arterial (VA) or Veno-Venous (VV) ECMO. Cardiogenic shock, acute respiratory distress syndrome (ARDS) and a combined respiratory and cardiogenic compromise were the primary indications for ECMO in 8 (50%), 5 (31%) and 3 (19%) patients respectively. The median time on ECMO was 8 days (range: 4 - 26 days). Twelve patients (75%) were successfully weaned off ECMO, of which four (25%) were bridged to a ventricular assist device (VAD) and eight (50%) were weaned to recovery. All eight patients (100%) that were weaned to recovery and two patients (50%) that were bridged to a VAD were successfully discharged from the hospital, resulting in a discharge rate of 63%. There was an improvement in pre- vs. post-ECMO AST (449 IU/L vs. 63 IU/L, p Conclusion: ECMO using the QuadroxD oxygenator and a centrifugal pump, coupled with standardized management protocols is beneficial in carefully selected patients. Improvement or main- tenance of end-organ function is associated with successful bridge to device therapy and/or increased survival.展开更多
文摘BACKGROUND In critical care practice,difficult airway management poses a substantial challenge,necessitating urgent intervention to ensure patient safety and optimize outcomes.Extracorporeal membrane oxygenation(ECMO)is a potential rescue tool in patients with severe airway compromise,although evidence of its efficacy and safety remains limited.AIM To review the local experience of using ECMO support in patients with difficult airway management.METHODS This retrospective case series study includes patients with difficult airway management who required ECMO support at a tertiary hospital in a Middle Eastern country.RESULTS Between 2016 and 2023,a total of 13 patients required ECMO support due to challenging airway patency in the operating room.Indications for ECMO encompassed various diagnoses,including tracheal stenosis,external tracheal compression,and subglottic stenosis.Surgical interventions such as tracheal resection and anastomosis often necessitated ECMO support to maintain adequate oxygenation and hemodynamic stability.The duration of ECMO support ranged from standby mode(ECMO implantation is readily available)to several days,with relatively infrequent complications observed.Despite the challenges encountered,most patients survived hospital discharge,highlighting the effectiveness of ECMO in managing difficult airways.CONCLUSION This study underscores the crucial role of ECMO as a life-saving intervention in selected cases of difficult airway management.Further research is warranted to refine the understanding of optimal management strategies and improve outcomes in this challenging patient population.
基金Project(21406273)supported by the National Natural Science Foundation of China
文摘Magneli phase titanium sub-oxide conductive ceramic Tin O2n-1 was used as the support for Pt due to its excellent resistance to electrochemical oxidation, and Pt/Tin O2n-1 composites were prepared by the impregnation-reduction method. The electrochemical stability of Tin O2n-1 was investigated and the results show almost no change in the redox region after oxidation for 20 h at 1.2 V(vs NHE) in 0.5 mol/L H2SO4 aqueous solution. The catalytic activity and stability of the Pt/Tin O2n-1 toward the oxygen reduction reaction(ORR) in 0.5 mol/L H2SO4 solution were investigated through the accelerated aging tests(AAT), and the morphology of the catalysts before and after the AAT was observed by transmission electron microscopy. At the potential of 0.55 V(vs SCE), the specific kinetic current density of the ORR on the Pt/Tin O2n-1 is about 1.5 times that of the Pt/C. The LSV curves for the Pt/C shift negatively obviously with the half-wave potential shifting about 0.02 V after 8000 cycles AAT, while no obvious change takes place for the LSV curves for the Pt/Tin O2n-1. The Pt particles supported on the carbon aggregate obviously, while the morphology of the Pt supported on Tin O2n-1 remains almost unchanged, which contributes to the electrochemical surface area loss of Pt/C being about 2times that of the Pt/Tin O2n-1. The superior catalytic stability of Pt/Tin O2n-1 toward the ORR could be attributed to the excellent stability of the Tin O2n-1 and the electronic interaction between the metals and the support.
基金the National Natural Science Foundation of China(20825310,20973011)the National Basic Research Program of China(973 Program,2011CB201400,2011CB808700)
文摘Au]Cel_xZrxO2 catalysts （x = 0-0.8） were prepared by a deposition-precipitation method using Cel_xZrxO2 nanoparticles as supports with variable Ce and Zr contents. Their structures were characterized by complimentary means such as X-ray diffraction, Raman, scanning trans- mission electron microscopy and X-ray photoelectron spectroscopy （XPS）. These Au catalysts possessed similar sizes and crystalline phases of Cel_xZrzO2 supports as well as similar sizes and oxidation states of Au nanoparticles. The oxidation state of Au nanoparticles was dominated by Au~ especially in CO oxidation. Their activities were examined in CO oxidation at different temperatures in the range of 303-333 K. The CO oxidation rates normalized per Au atoms increased with the increasing Ce contents, and reached the maximum value over Au/CeO2. Such change was in parallel with the change in the oxygen storage capacity values, i.e. the amounts of active oxygen species on Au/Cel_zZrzO2 catalysts. The excellent correlation between the two properties of the catalysts suggests that the intrinsic support effects on the CO oxidation rates is related to the effects on the adsorption and activation of O2 on Au/Cel_xZrxO2 catalysts. Such understanding on the support effects may be useful for designing more active Au catalysts, for example, by tuning the redox properties of oxide supports.
基金Project supported by Center of Excellence for Innovation in Chemistry(PERCH-CIC)Commission on Higher Education,Ministry of Education and the Center of Alternative Energy Research and Development,Khon Kaen University
文摘In this work, the addition of praseodymium（Pr） into ceria as a mixed oxide support in a form of Ce（1-x）PrxO2（x = 0.01,0.025, 0.050, 0.075 and 0.10） was prepared using a co-precipitation method. The structural and textural properties of the synthesized supports were characterized by X-ray diffraction（XRD）, N2 adsorption-desorption, Raman spectroscopy, H2-temperature programmed reduction（H2-TPR） and H2-chemisorption. Upon addition of Pr, XRD patterns and Raman spectra indicated an enlargement of ceria unit cell and the characteristics Raman broad peak at 570 cm^（-1） which was attributed to the existence of oxygen vacancies in the ceria lattice. This indicated that some Ce^（4＋） ions in ceria were replaced by larger Pr^（3＋） cations. To evidence the incorporation of Pr^（3＋） cations into ceria lattice,X-ray absorption near edge structure（XANES） was employed. The results showed that the oxidation states of Ce in mixed oxide supports were slightly lower than 4＋ while those of Pr were still the same as a precursor salt. Therefore, the incorporation of Pr^（3＋） into ceria lattice would lead to strain and unbalanced charge and result in oxygen vacancies. The reducibility of Ce（1-x）PrxO2 mixed oxide supports was investigated by H2-TPR and temperature-resolved X-ray absorption spectroscopy experiment under reduction conditions. XANES spectra of Ce L3 edges showed a lower surface reduction temperature（Ce^（4＋）to Ce^（3＋）） of Ce（0.925）Pr（0.075）O2 than that of CeO2 which agreed with H2-TPR results. H2-chemisorption indicated that Pr promoted the dispersion of the metal catalyst on the mixed oxide support and increased the adsorption site for CO. For WGS reaction, 1% Pd/mixed oxide support had higher WGS activity than 1%Pd/ceria. The increase of WGS activity was due to the increase of Pd dispersion on the support and the existence of oxygen vacancies produced from incorporation of Pr into the ceria lattice.
文摘It has been generally recognised that the metal catalysts supported on oxide ceramic and non-oxide ceramic supports exhibit completely different characteristics as compared with the homogeneous ones. The na-ture of bonding and interactions occurring at the metal / ceramic interfaces are believed to be of importancefor the characteristics of such catalysts. The recently developed microscopic theory of adhesion and wettingin metal/ ceramic systems is briefly presented here with the emphasis on the ionocovalent oxide ceramics.and its consequence on the understanding of the physical and chemical behaviours of supported metal cata-lysts is exploited.
文摘BACKGROUND Very little is known about the role of extracorporeal membrane oxygenation(ECMO)for the management of patients undergoing major aortic surgery with particular reference to aortic dissection.AIM To review the available literature to determine if there was any evidence.METHODS A systematic literature search through PubMed and EMBASE was undertaken according to specific key words.RESULTS The search resulted in 29 publications relevant to the subject:1 brief communication,1 surgical technique report,1 invited commentary,1 retrospective case review,1 observational study,4 retrospective reviews,13 case reports and 7 conference abstracts.A total of 194 patients were included in these publications of whom 77 survived.CONCLUSION Although there is no compelling evidence for or against the use of ECMO in major aortic surgery or dissection,it is enough to justify its use in this patient population despite current adverse attitude.
文摘Introduction: World Health Organization announced on April 2009 a public health emergency of international concern caused by swine-origin influenza A(H1N1) virus. Acute respiratory distress syndrome(ARDS) has been reported to be the most devastating complications of this pathogen. Extracorporeal membrane oxygenator(ECMO) therapy for patients with H1N1 related ARDS has been described once all other therapeutic options have been exhausted. Here, we report the case of a child(German, male) with H1N1-associated fulminate respiratory and secondary hemodynamic deterioration who was rescued by initial emergent ECMO established through a dialysis catheter and subsequent switch to central cannulation following median sternotomy. This report highlights several important issues. First, it describes a successful use of a dialysis catheter for the establishment of a veno-venous ECMO in an emergency case by child. Second, it highlights the importance of a closely monitoring of clotting parameters during ECMOtherapy and third, if severe respiratory failure is complicated by cardiogenic shock, veno-atrial ECMO support via median sternotomy should be considered as a viable treatment option without further delay.
文摘EHMO calculations and orbital analyses of fragment;;have been performed for the formation of oxygenates in Fischer-Tropsch synthesis on the butterfly model for four different metal (Ni,Ru,Rh,Pd) catalysts supported on SiO2.Calculations were made for the four processes,i.e.,CO-dissociation;Coupling of CO and H to produce CHO;Insertion of CO to M-CH3;insertion of CH2 to M-CH3 On the basis of comparing the degree of CO bonds activation and the energy barriers of the foregoing processes for these four catalysts,it is concluded that Ni/SiO2 can be used as the methanation catalyst.On Ru/SiO2 and Rh/SiO2 C2-oxygenated compound can be produced (acetaldehyde),especially Rh/SiO2 is the even better catalyst,and Pd/SiO2 is a methanol synthesis catalyst.
文摘Porous carbon nanofibers (PCNFs) were prepared through electrospinning, pre-oxidation and carbonization with polyacrylonitrile (PAN) as carbon precursor and polymethyl methacrylate (PMMA), CaCO3 as pore-forming agents. The structure, morphology, specific surface area and electrochemical performance of the carbon nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption/desorption method and electrochemical tests. Compared with PCNFs without CaCO3, PCNFs(CaCO3 1%) had higher specific surface area, better dispersion of Pt nanoparticles, and the particle size become smaller, which was corresponding with the results of electrochemical performance test. It could be seen in cyclic voltammetry (CV) and linear sweep voltammetry (LSV) test, ECSA of Pt/PCNFs (CaCO3 1%) attained 82 m2?g?1, while that of JM20 and Pt/PCNFs without CaCO3 were 77 m2?g?1 and 60 m2?g?1, respectively. These results revealed that CaCO3 as the second pore-forming agent can further increase the mesoporous number and specific surface area of nanofibers, and can improve the electrochemical properties of Pt catalyst as the support.
基金The Natural Science Foundation of China (No.20273057,20473070).
文摘Gold catalysts supported on SiO2, TiO2, TiO2-SiO2, and ZrO2-SiO2 supports were prepared by impregnating each support with a basic solution of tetrachloroauric acid. X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and X-ray photoelectron spectroscopy （XPS） techniques were used to characterize their structure and surface composition. The results indicated that the size of gold particles could be controlled to below 10 nm by this method of preparation. Washing gold catalysts with water could markedly enhance the dispersion of metallic gold particles on the surface, but it could not completely remove the chloride ions left on the surface. The catalytic performance of direct vapor-phase epoxidation of propylene using air as an oxidant over these catalysts was evaluated at atmospheric pressure. The selectivity to propylene oxide （PO） was found to vary with reaction time on the stream. At the reaction conditions of atmosphere pressure, temperature 325 ℃, feed gas ratio V（C3H6）/V（O2）= 1/2, and GHSV =6000h^-1, 17.9% PO selectivity with 0.9% propylene conversion were obtained at initial 10 min for Au/SiO2 catalyst. After reacting 60 min only 8.9% PO selectivity were detected, but the propylene conversion rises to 1.4% and the main product is transferred to acrolein （72% selectivity）. Washing Au/TiO2-SiO2 and Aa/ZrO2-SiO2 samples with magnesium citrate solution could markedly enhance the activity and PO selectivity because smaller gold particles were obtained.
文摘Lung transplant is the standard of care for patients with end-stage lung disease refractory to medical management. There is currently a critical organ shortage for lung transplantation with only 17% of offered organs being transplanted. Of those patients receiving a lung transplant, up to 25% will develop primary graft dysfunction, which is associated with an 8-fold increase in 30-d mortality. There are numerous mechanical lung assistance modalities that may be employed to help combat these challenges. We will discuss the use of mechanical lung assistance during lung transplantation, as a bridge to transplant, as a treatment for primary graft dysfunction, and finally as a means to remodel and evaluate organs deemed unsuitable for transplant, thus increasing the donor pool, improving survival to transplant, and improving overall patient survival.
文摘Introduction: Extracorporeal Membrane Oxygenation (ECMO) is used in selected patient with cardiogenic and/or re- spiratory shock. We report our experience with standardized management protocols and the application of the Qua- droxD oxygenator with a centrifugal pump to maximize end-organ recovery and improve survival. Methods: This is an Internal Review Board (IRB) approved, single institution retrospective study of end-organ recovery and survival in pa- tients who required ECMO for cardiogenic and/or respiratory shock between July 2010 and June 2011. Results: Sixteen patients (median age: 46 years) were initiated on either Veno-Arterial (VA) or Veno-Venous (VV) ECMO. Cardiogenic shock, acute respiratory distress syndrome (ARDS) and a combined respiratory and cardiogenic compromise were the primary indications for ECMO in 8 (50%), 5 (31%) and 3 (19%) patients respectively. The median time on ECMO was 8 days (range: 4 - 26 days). Twelve patients (75%) were successfully weaned off ECMO, of which four (25%) were bridged to a ventricular assist device (VAD) and eight (50%) were weaned to recovery. All eight patients (100%) that were weaned to recovery and two patients (50%) that were bridged to a VAD were successfully discharged from the hospital, resulting in a discharge rate of 63%. There was an improvement in pre- vs. post-ECMO AST (449 IU/L vs. 63 IU/L, p Conclusion: ECMO using the QuadroxD oxygenator and a centrifugal pump, coupled with standardized management protocols is beneficial in carefully selected patients. Improvement or main- tenance of end-organ function is associated with successful bridge to device therapy and/or increased survival.
