A titania support with a large surface area was developed, which has a BET surface area of 380.5 m^2/g, four times that of a traditional titania support. The support was ultrasonically impregnated with 5 wt% vanadia. ...A titania support with a large surface area was developed, which has a BET surface area of 380.5 m^2/g, four times that of a traditional titania support. The support was ultrasonically impregnated with 5 wt% vanadia. A special heat treatment was used in the calcination to maintain the large surface area and high dispersion of vanadium species. This catalyst was compared to a common V2O5-TiO2 catalyst with the same vanadia loading prepared by a traditional method. The new catalyst has a surface area of 117.7 m^2/g, which was 38% higher than the traditional V2O5-TiO2 catalyst. The selective catalytic reduction（SCR） performance demonstrated that the new catalyst had a wider temperature window and better N2 selectivity compared to the traditional one. The NO conversion was 80% from 200 to 450 °C. The temperature window was 100 °C wider than the traditional catalyst. Raman spectra indicated that the vanadium species formed more V-O-V linkages on the catalyst prepared by the traditional method. The amount of V-O-Ti and V=O was larger for the new catalyst. Temperature programmed desorption of NH3, temperature programmed reduction by H2 and X-ray photoelectron spectroscopy results showed that its redox ability and total acidity were enhanced. The results are helpful for developing a more efficient SCR catalyst for the removal of NOx in flue gases.展开更多
A practical approach was introduced to study the inclusion mechanism of chlorine in high purity copper electrorefining from nitric acid system via cyclic voltammetry(CV) combined with electrodeposition experiments. Th...A practical approach was introduced to study the inclusion mechanism of chlorine in high purity copper electrorefining from nitric acid system via cyclic voltammetry(CV) combined with electrodeposition experiments. The CV curves display an obvious reduction peak of Cu Cl intermediate, which can provide an insight into the electrochemical behavior of this inclusion. Experimental results show that the increase of HNO3 concentration is favorable to reducing the quantity of chlorine inclusion although there is a slight decline in cathodic current efficiency. The optimum conditions for copper electrorefining in nitric acid system are HNO3 concentration in solution of 1-2 mol/L, moderate temperature of ~35 ℃ with current density not exceeding 25 m A/cm2. Based on the theoretical studies, an optimized copper electrorefining experiment was designed to simulate the industrial electrolysis, by which high purity copper can be obtained with chlorine inclusion less than 10 μg/g and current efficiency higher than 90%.展开更多
In a high concentration substrate medium, a heterotrophic bacterium with high removal efficiency of ammonium, named W1, was isolated from activated sludge of coking wastewater treatment facility. The bacterium was Gra...In a high concentration substrate medium, a heterotrophic bacterium with high removal efficiency of ammonium, named W1, was isolated from activated sludge of coking wastewater treatment facility. The bacterium was Gram-negative, rod-shaped, and identified preliminarily as Alcaligenes sp. according to its morphological and physiological properties and its 16S rRNA gene sequence analysis. In the high concentration ammonium medium (400 mg·L 1 4 NH -N), the effects of C source, N source, C/N ratio and initial pH of medium on ammonium removal were investigated in order to determine the optimal condition for strain W1. The maximum ammonium removal was around 95% in 4 days in an improved medium. The production of N 2 gas was examined in a closed system that was full of pure oxygen at the beginning. N 2 gas was detected in the system after 4 days of cultivation, which further testified that strain W1 has heterotrophic nitrification and aerobic denitrification abilities simultaneously.展开更多
The cardiac and vascular effect of ethanolamine nitrate ester ferulate (ENF) wasinvestigated on isolated working guinea pig heart (IWH) and rat aortic ring. The coronary blood flowwas remarkably increased while the c...The cardiac and vascular effect of ethanolamine nitrate ester ferulate (ENF) wasinvestigated on isolated working guinea pig heart (IWH) and rat aortic ring. The coronary blood flowwas remarkably increased while the cardiac functions of IWH were not significantly altered by ENFranging from 10-8 to 10-4 mol/L. The percentages of vasorelaxation of ENF t 10 μmol/L) and nicoran-dil (NIC, 10 μmol/L) on K+ (80 mmol/L)-induced contraction in aortic rings were 72 ± 8% and17±8%, respectively. The relaxation effects of ENF and NIC on phenylephrine (PE, 5 μmol/L) in-duced contraction were in a dose-dependent manner. When vessel segments were exposed to PE withmethylene blue (MB, 10 μmol/L) or with glibenclamide (GLI, 10 pmol/L), the percentages of relaxa-tion of ENF (10 μmol/L) and NIC ( 1 0 μmol/L) were 4 1 ±11 % and 49±7% or 76± 14% and the 33±9%,respectively. The results suggested that ENF improved coronary circulation and the vasodilation of ENF was mediated bv nitrate-like action.展开更多
A novel strain of Micrococcus sp.DUT_AHX,which was isolated from the sludge of a nitrobenzene(NB)-manufacturing plant and could utilize NB as the sole carbon source,was identified on the basis of physiological and bio...A novel strain of Micrococcus sp.DUT_AHX,which was isolated from the sludge of a nitrobenzene(NB)-manufacturing plant and could utilize NB as the sole carbon source,was identified on the basis of physiological and biochemical tests and 16S ribosomal DNA(rDNA)sequence analysis.It can grow at the temperature up to 40℃or in the presence of NaCl concentration up to 12 g/L in Luria-Bertani(LB)medium.The optimal degradation conditions are as follows:temperature 37℃,pH 7.0,and shaking speed 150 r/min.The strain involves a partial reductive pathway due to the release of ammonia and can also utilize 2-aminophenol as the sole carbon source.Furthermore,the enzyme activity tests show that crude extracts of NB-grown strain DUT_AHX mainly contain 2-aminophenol 1,6-dioxygenase activity.The exploitation of salt-tolerant bacteria will be a remarkable improvement in NB bioremediation and wastewater treatment at high salinity and high temperature.展开更多
The catalytic hydrogenation of p-nitrophenol to p-aminophenol was investigated over Ni/TiO2 catalysts prepared by a liquid-phase chemical reduction method. The catalysts were characterized by inductively coupled plasm...The catalytic hydrogenation of p-nitrophenol to p-aminophenol was investigated over Ni/TiO2 catalysts prepared by a liquid-phase chemical reduction method. The catalysts were characterized by inductively coupled plasma (ICP), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS) and temperature-programmed reduction (TPR). Results show that the titania structure has favorable influence on physio-chemical and catalytic properties of Ni/TiO2 catalysts. Compared to commercial Raney nickel, the catalytic activity of Ni/TiO2 catalyst is much superior, irrespective of the titania structure. The catalytic activity of anatase titania supported nickel catalyst Ni/TiO2(A) is higher than that of rutile titania supported nickel catalyst Ni/TiO2(R), possibly because the reduction of nickel oxide to metallic nickel for Ni/TiO2(A) is easier than that for Ni/TiO2(R) at similar reaction conditions.展开更多
2-Methyl-4-methoxyaniline （MMA） was synthesized by one-pot method through the hydrogenation and Bamberger rearrangement of o-nitrotoluene in methanol using acidic ionic liquid and 3% Pt/C as catalyst system. The eff...2-Methyl-4-methoxyaniline （MMA） was synthesized by one-pot method through the hydrogenation and Bamberger rearrangement of o-nitrotoluene in methanol using acidic ionic liquid and 3% Pt/C as catalyst system. The effects of ionic liquid type, dosage of ionic liquid and 3% Pt/C, reaction temperature and reaction pressure on o-nitrotoluene conversion and MMA selectivity were investigated. The results indicated that the imidazolium-based acidic ionic liquid which contains SO3H-functionalized cation showed higher selectivity to MMA than other acidic ionic liquids used in this work. Using 1-（propyl-3-sulfonate）-3-methylimidazolium hydrosulfate （[HSO3-pmim][HSO4]） as the acid catalyst, the selectivity to MMA was as high as 67.6% at 97.8% of o-nitrotoluene conversion. As 3% Pt/C increased from 0.01 g to 0.025 g, the selectivity to MMA decreased from 73.4% to 62.5%, because of the hydrogenation of intermediate o-methyl-phenylhydroxylamine to o-toluidine becoming more dominant. An increase in hydrogen pressure also had obviously dramatic effect in lowering the MMA selectivity. After easy separation from the products, the catalyst system could be reused at least 3 times.展开更多
A highly efficient and reusable plane‐curved and interlayer‐expanded MoS2nanocatalyst with increased exposure of active sites was prepared.The catalyst was used for the heterogeneous hydrogen transfer reaction of ni...A highly efficient and reusable plane‐curved and interlayer‐expanded MoS2nanocatalyst with increased exposure of active sites was prepared.The catalyst was used for the heterogeneous hydrogen transfer reaction of nitroarenes with hydrazine monohydrate as a reductant under mild reaction conditions without pressure and base,which was different from other hydrogen transfer systems that require the presence of a base(e.g.,propan‐2‐ol/KOH).The sandwiching of carbon between the MoS2nanosheets increased the distance between the layers of MoS2and exposed more Mo sites,resulting in superior catalytic performance compared with that of bulk MoS2catalyst.The active hydrogen(H*)generated from N2H4could directly transfer to the–NO2groups of nitrobenzene to form aniline followed by N2emission,which was confirmed by detecting the gas emission with mass spectrometry during the decomposition of hydrazine or the co‐existence of nitrobenzene and hydrazine.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.展开更多
The crystal structure of crown ether-hydrogen bonded complex,[La(NO3)3 (12-crown-4) ( H2O)] (12-crown-4) has been determined by X-ray method. The title complex C16H34LaN3O18 (Mr=695. 5) crystallized in orthorhombic ...The crystal structure of crown ether-hydrogen bonded complex,[La(NO3)3 (12-crown-4) ( H2O)] (12-crown-4) has been determined by X-ray method. The title complex C16H34LaN3O18 (Mr=695. 5) crystallized in orthorhombic Pnma with a=23. 495(8), b=13. 603(5),c=8. 474(3); V=2706(1); Z=4 ; Dc=1. 71 g/cm3; F(000)=1408, μ=17. 0 cm-1 (MOKα). The final R=0. 052 and Rw= 0. 054(unit weight) for 1367 observed reflections. The La( Ⅲ) ion is 11-coordinated by three nitrale anions, four oxygen atoms from a crown ligand and one O atom of a water molecule. The other crown molecule is hydrogen bonded wilh the coordinated water molecule. The imposed mirror plane in the structure made both crown ligands and one of nitrate groups severely disordered.展开更多
AIM: To systematically assess the efficacy and safety of β-adrenergic blocker plus 5-isosorbide mononitrate (BB + ISMN) and endoscopic band ligation (EBL) on prophylaxis of esophageal variceal rebleeding. METHODS: Ra...AIM: To systematically assess the efficacy and safety of β-adrenergic blocker plus 5-isosorbide mononitrate (BB + ISMN) and endoscopic band ligation (EBL) on prophylaxis of esophageal variceal rebleeding. METHODS: Randomized controlled trials (RCTs) comparing the efficacy and safety of BB + ISMN and EBL on prophylaxis of esophageal variceal rebleeding were gathered from Medline, Embase, Cochrane Controlled Trial Registry and China Biological Medicine database between January 1980 and August 2007. Data from five trials were extracted and pooled. The analyses of the available data using the Revman 4.2 software were based on the intention-to-treat principle. RESULTS: Four RCTs met the inclusion criteria. In comparison with BB + ISMN with EBL in prophylaxis of esophageal variceal rebleeding, there was no significant difference in the rate of rebleeding [relative risk (RR), 0.79; 95% CI: 0.62-1.00; P = 0.05], bleeding-related mortality (RR, 0.76; 95% CI: 0.31-1.42; P = 0.40), overall mortality (RR, 0.81; 95% CI: 0.61-1.08; P = 0.15) and complications (RR, 1.26; 95% CI: 0.93-1.70; P = 0.13). CONCLUSION:In the prevention of esophageal variceal rebleeding, BB + ISMN are as effective as EBL. There are few complications with the two treatment modalities. Both BB + ISMN and EBL would be considered as the first-line therapy in the prevention of esophageal variceal rebleeding.展开更多
The synthesis and crystal structures of Ln(NO3)3(Ln=La,Yb) complexes with 12-crown-4 are reported. La (NO3 )3 (12-crown-4) (H2O)x(Ln=La,x=1; Ln=Yb, x=0), Mr=519. 2(535.3), space group P21/n(P21/c)with α =7. 612(2)(1...The synthesis and crystal structures of Ln(NO3)3(Ln=La,Yb) complexes with 12-crown-4 are reported. La (NO3 )3 (12-crown-4) (H2O)x(Ln=La,x=1; Ln=Yb, x=0), Mr=519. 2(535.3), space group P21/n(P21/c)with α =7. 612(2)(12. 116(3)), b=13. 932(6) (8. 544(3)),c= 16. 179(6) (15.241 (3));β=101.40 (2)( 91.82 (2))°; V=1682 (1) (1577(1)); Z=4 (4);μ(MoKα)=26.7(63.2) cm -1; F(000) =1024 (1036) ; R=0. 035 (0. 034) ; Rw= 0. 028 (0.036) for 1665 (1594) observed reflections with Ⅰ>3σ(Ⅰ). The La(Ⅲ) ion in La (NO3)3 (12-crown-4) (H2O) is 11-coordinated, being bonded to three bidentate nitrate ions , four oxygen atoms of the crown molecule and one oxygen atom of a water molecule. Yb(NO3)3 (12-crown-4) is a 10-coordinated complex, in which the metal ion bonds with three bidentate nitrate ions and four oxygen atoms of a crown ether.展开更多
Denitrification and nitrate reduction to ammonium in Taihu Lake and Yellow Sea inter-tidal marinesediments were studied. The sediment samples were made into slurry containing 150 g dry matter per liter.Various amounts...Denitrification and nitrate reduction to ammonium in Taihu Lake and Yellow Sea inter-tidal marinesediments were studied. The sediment samples were made into slurry containing 150 g dry matter per liter.Various amounts of glucose and 5 mmol L-1 of potassium nitrate were added in order to achieve differentratios of glucose-C to nitrate-N. Acetylene inhibition technique was applied to measure denitrification in theslumes. All samples were incubated anaerobically under argon atmosphere. Data showed that Taihu Lakesediment produced more N2O than marine sediment. Denitrification potential was higher in Taihu Lakesediment than in marne one. Glucose added increased denitrification activity but not the denitrification po-tential of the sediments. Dissimilatory nitrate reduction to ammonium seemed to occur in marine sediment,but not in freshwater one. When the marine sediment was treated with 25 mmol L-1 glucose, its denitrification poteatial, as indicated by maximum N2O production by acetylene blockage, was lower than that treatedwith no or 2.5 mmol L-l glucose. Acetylene was suspected to have inhibitory effect on dissimilatory nitratereduction to ammonium.展开更多
基金supported by the National Natural Science Foundation of China(21325731,21221004)the National High Technology Research and Development Program of China(863 Program)the State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex
文摘A titania support with a large surface area was developed, which has a BET surface area of 380.5 m^2/g, four times that of a traditional titania support. The support was ultrasonically impregnated with 5 wt% vanadia. A special heat treatment was used in the calcination to maintain the large surface area and high dispersion of vanadium species. This catalyst was compared to a common V2O5-TiO2 catalyst with the same vanadia loading prepared by a traditional method. The new catalyst has a surface area of 117.7 m^2/g, which was 38% higher than the traditional V2O5-TiO2 catalyst. The selective catalytic reduction（SCR） performance demonstrated that the new catalyst had a wider temperature window and better N2 selectivity compared to the traditional one. The NO conversion was 80% from 200 to 450 °C. The temperature window was 100 °C wider than the traditional catalyst. Raman spectra indicated that the vanadium species formed more V-O-V linkages on the catalyst prepared by the traditional method. The amount of V-O-Ti and V=O was larger for the new catalyst. Temperature programmed desorption of NH3, temperature programmed reduction by H2 and X-ray photoelectron spectroscopy results showed that its redox ability and total acidity were enhanced. The results are helpful for developing a more efficient SCR catalyst for the removal of NOx in flue gases.
基金Project(LY17B030009)supported by the Natural Science Foundation of Zhejiang Province,China。
文摘A practical approach was introduced to study the inclusion mechanism of chlorine in high purity copper electrorefining from nitric acid system via cyclic voltammetry(CV) combined with electrodeposition experiments. The CV curves display an obvious reduction peak of Cu Cl intermediate, which can provide an insight into the electrochemical behavior of this inclusion. Experimental results show that the increase of HNO3 concentration is favorable to reducing the quantity of chlorine inclusion although there is a slight decline in cathodic current efficiency. The optimum conditions for copper electrorefining in nitric acid system are HNO3 concentration in solution of 1-2 mol/L, moderate temperature of ~35 ℃ with current density not exceeding 25 m A/cm2. Based on the theoretical studies, an optimized copper electrorefining experiment was designed to simulate the industrial electrolysis, by which high purity copper can be obtained with chlorine inclusion less than 10 μg/g and current efficiency higher than 90%.
基金Supported by the National Natural Science Foundation of China (51078252)the International Cooperation Projects of Shanxi Province (2010081018)the Natural Science Foundation of Shanxi Province (2010011016-1)
文摘In a high concentration substrate medium, a heterotrophic bacterium with high removal efficiency of ammonium, named W1, was isolated from activated sludge of coking wastewater treatment facility. The bacterium was Gram-negative, rod-shaped, and identified preliminarily as Alcaligenes sp. according to its morphological and physiological properties and its 16S rRNA gene sequence analysis. In the high concentration ammonium medium (400 mg·L 1 4 NH -N), the effects of C source, N source, C/N ratio and initial pH of medium on ammonium removal were investigated in order to determine the optimal condition for strain W1. The maximum ammonium removal was around 95% in 4 days in an improved medium. The production of N 2 gas was examined in a closed system that was full of pure oxygen at the beginning. N 2 gas was detected in the system after 4 days of cultivation, which further testified that strain W1 has heterotrophic nitrification and aerobic denitrification abilities simultaneously.
文摘The cardiac and vascular effect of ethanolamine nitrate ester ferulate (ENF) wasinvestigated on isolated working guinea pig heart (IWH) and rat aortic ring. The coronary blood flowwas remarkably increased while the cardiac functions of IWH were not significantly altered by ENFranging from 10-8 to 10-4 mol/L. The percentages of vasorelaxation of ENF t 10 μmol/L) and nicoran-dil (NIC, 10 μmol/L) on K+ (80 mmol/L)-induced contraction in aortic rings were 72 ± 8% and17±8%, respectively. The relaxation effects of ENF and NIC on phenylephrine (PE, 5 μmol/L) in-duced contraction were in a dose-dependent manner. When vessel segments were exposed to PE withmethylene blue (MB, 10 μmol/L) or with glibenclamide (GLI, 10 pmol/L), the percentages of relaxa-tion of ENF (10 μmol/L) and NIC ( 1 0 μmol/L) were 4 1 ±11 % and 49±7% or 76± 14% and the 33±9%,respectively. The results suggested that ENF improved coronary circulation and the vasodilation of ENF was mediated bv nitrate-like action.
文摘A novel strain of Micrococcus sp.DUT_AHX,which was isolated from the sludge of a nitrobenzene(NB)-manufacturing plant and could utilize NB as the sole carbon source,was identified on the basis of physiological and biochemical tests and 16S ribosomal DNA(rDNA)sequence analysis.It can grow at the temperature up to 40℃or in the presence of NaCl concentration up to 12 g/L in Luria-Bertani(LB)medium.The optimal degradation conditions are as follows:temperature 37℃,pH 7.0,and shaking speed 150 r/min.The strain involves a partial reductive pathway due to the release of ammonia and can also utilize 2-aminophenol as the sole carbon source.Furthermore,the enzyme activity tests show that crude extracts of NB-grown strain DUT_AHX mainly contain 2-aminophenol 1,6-dioxygenase activity.The exploitation of salt-tolerant bacteria will be a remarkable improvement in NB bioremediation and wastewater treatment at high salinity and high temperature.
基金Supported by the National Basic Research Program (No.2003CB615702) and the National Natural Science Foundation of Chin(No.20436030).
文摘The catalytic hydrogenation of p-nitrophenol to p-aminophenol was investigated over Ni/TiO2 catalysts prepared by a liquid-phase chemical reduction method. The catalysts were characterized by inductively coupled plasma (ICP), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS) and temperature-programmed reduction (TPR). Results show that the titania structure has favorable influence on physio-chemical and catalytic properties of Ni/TiO2 catalysts. Compared to commercial Raney nickel, the catalytic activity of Ni/TiO2 catalyst is much superior, irrespective of the titania structure. The catalytic activity of anatase titania supported nickel catalyst Ni/TiO2(A) is higher than that of rutile titania supported nickel catalyst Ni/TiO2(R), possibly because the reduction of nickel oxide to metallic nickel for Ni/TiO2(A) is easier than that for Ni/TiO2(R) at similar reaction conditions.
基金Supported by the National Natural Science Foundation of China （21106134） and the Natural Science Foundation of Zlaejlang Province （Y4100671）.
文摘2-Methyl-4-methoxyaniline （MMA） was synthesized by one-pot method through the hydrogenation and Bamberger rearrangement of o-nitrotoluene in methanol using acidic ionic liquid and 3% Pt/C as catalyst system. The effects of ionic liquid type, dosage of ionic liquid and 3% Pt/C, reaction temperature and reaction pressure on o-nitrotoluene conversion and MMA selectivity were investigated. The results indicated that the imidazolium-based acidic ionic liquid which contains SO3H-functionalized cation showed higher selectivity to MMA than other acidic ionic liquids used in this work. Using 1-（propyl-3-sulfonate）-3-methylimidazolium hydrosulfate （[HSO3-pmim][HSO4]） as the acid catalyst, the selectivity to MMA was as high as 67.6% at 97.8% of o-nitrotoluene conversion. As 3% Pt/C increased from 0.01 g to 0.025 g, the selectivity to MMA decreased from 73.4% to 62.5%, because of the hydrogenation of intermediate o-methyl-phenylhydroxylamine to o-toluidine becoming more dominant. An increase in hydrogen pressure also had obviously dramatic effect in lowering the MMA selectivity. After easy separation from the products, the catalyst system could be reused at least 3 times.
基金supported by the Ministry of Science and Technology(MOST,2016YFA0204100 and 2011CBA00504)the National Natural Science Foundation of China(21573254,91545110)+1 种基金the Youth Innovation Promotion Association(CAS)the Sinopec China~~
文摘A highly efficient and reusable plane‐curved and interlayer‐expanded MoS2nanocatalyst with increased exposure of active sites was prepared.The catalyst was used for the heterogeneous hydrogen transfer reaction of nitroarenes with hydrazine monohydrate as a reductant under mild reaction conditions without pressure and base,which was different from other hydrogen transfer systems that require the presence of a base(e.g.,propan‐2‐ol/KOH).The sandwiching of carbon between the MoS2nanosheets increased the distance between the layers of MoS2and exposed more Mo sites,resulting in superior catalytic performance compared with that of bulk MoS2catalyst.The active hydrogen(H*)generated from N2H4could directly transfer to the–NO2groups of nitrobenzene to form aniline followed by N2emission,which was confirmed by detecting the gas emission with mass spectrometry during the decomposition of hydrazine or the co‐existence of nitrobenzene and hydrazine.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.
文摘The crystal structure of crown ether-hydrogen bonded complex,[La(NO3)3 (12-crown-4) ( H2O)] (12-crown-4) has been determined by X-ray method. The title complex C16H34LaN3O18 (Mr=695. 5) crystallized in orthorhombic Pnma with a=23. 495(8), b=13. 603(5),c=8. 474(3); V=2706(1); Z=4 ; Dc=1. 71 g/cm3; F(000)=1408, μ=17. 0 cm-1 (MOKα). The final R=0. 052 and Rw= 0. 054(unit weight) for 1367 observed reflections. The La( Ⅲ) ion is 11-coordinated by three nitrale anions, four oxygen atoms from a crown ligand and one O atom of a water molecule. The other crown molecule is hydrogen bonded wilh the coordinated water molecule. The imposed mirror plane in the structure made both crown ligands and one of nitrate groups severely disordered.
文摘AIM: To systematically assess the efficacy and safety of β-adrenergic blocker plus 5-isosorbide mononitrate (BB + ISMN) and endoscopic band ligation (EBL) on prophylaxis of esophageal variceal rebleeding. METHODS: Randomized controlled trials (RCTs) comparing the efficacy and safety of BB + ISMN and EBL on prophylaxis of esophageal variceal rebleeding were gathered from Medline, Embase, Cochrane Controlled Trial Registry and China Biological Medicine database between January 1980 and August 2007. Data from five trials were extracted and pooled. The analyses of the available data using the Revman 4.2 software were based on the intention-to-treat principle. RESULTS: Four RCTs met the inclusion criteria. In comparison with BB + ISMN with EBL in prophylaxis of esophageal variceal rebleeding, there was no significant difference in the rate of rebleeding [relative risk (RR), 0.79; 95% CI: 0.62-1.00; P = 0.05], bleeding-related mortality (RR, 0.76; 95% CI: 0.31-1.42; P = 0.40), overall mortality (RR, 0.81; 95% CI: 0.61-1.08; P = 0.15) and complications (RR, 1.26; 95% CI: 0.93-1.70; P = 0.13). CONCLUSION:In the prevention of esophageal variceal rebleeding, BB + ISMN are as effective as EBL. There are few complications with the two treatment modalities. Both BB + ISMN and EBL would be considered as the first-line therapy in the prevention of esophageal variceal rebleeding.
文摘The synthesis and crystal structures of Ln(NO3)3(Ln=La,Yb) complexes with 12-crown-4 are reported. La (NO3 )3 (12-crown-4) (H2O)x(Ln=La,x=1; Ln=Yb, x=0), Mr=519. 2(535.3), space group P21/n(P21/c)with α =7. 612(2)(12. 116(3)), b=13. 932(6) (8. 544(3)),c= 16. 179(6) (15.241 (3));β=101.40 (2)( 91.82 (2))°; V=1682 (1) (1577(1)); Z=4 (4);μ(MoKα)=26.7(63.2) cm -1; F(000) =1024 (1036) ; R=0. 035 (0. 034) ; Rw= 0. 028 (0.036) for 1665 (1594) observed reflections with Ⅰ>3σ(Ⅰ). The La(Ⅲ) ion in La (NO3)3 (12-crown-4) (H2O) is 11-coordinated, being bonded to three bidentate nitrate ions , four oxygen atoms of the crown molecule and one oxygen atom of a water molecule. Yb(NO3)3 (12-crown-4) is a 10-coordinated complex, in which the metal ion bonds with three bidentate nitrate ions and four oxygen atoms of a crown ether.
文摘Denitrification and nitrate reduction to ammonium in Taihu Lake and Yellow Sea inter-tidal marinesediments were studied. The sediment samples were made into slurry containing 150 g dry matter per liter.Various amounts of glucose and 5 mmol L-1 of potassium nitrate were added in order to achieve differentratios of glucose-C to nitrate-N. Acetylene inhibition technique was applied to measure denitrification in theslumes. All samples were incubated anaerobically under argon atmosphere. Data showed that Taihu Lakesediment produced more N2O than marine sediment. Denitrification potential was higher in Taihu Lakesediment than in marne one. Glucose added increased denitrification activity but not the denitrification po-tential of the sediments. Dissimilatory nitrate reduction to ammonium seemed to occur in marine sediment,but not in freshwater one. When the marine sediment was treated with 25 mmol L-1 glucose, its denitrification poteatial, as indicated by maximum N2O production by acetylene blockage, was lower than that treatedwith no or 2.5 mmol L-l glucose. Acetylene was suspected to have inhibitory effect on dissimilatory nitratereduction to ammonium.
