AIM: To assess the diagnostic value of a combination of continuous intragastric pH and bilirubin monitoring in the detection of duodenogastric reflux (DGR), and the effects of diet on the bilirubin absorbance. METHODS...AIM: To assess the diagnostic value of a combination of continuous intragastric pH and bilirubin monitoring in the detection of duodenogastric reflux (DGR), and the effects of diet on the bilirubin absorbance. METHODS: 30 healthy volunteers were divided into two groups: standard diet group (Group 1) 18 cases, free diet group (Group 2)12 cases. Each subjects were subjected to simultaneous 24-hour intragastric pH and spectrophotometric bilirubin concentration monitoring (Bilitec 2000). RESULTS: There was no difference of preprandial phase bilirubin absorbance between two groups. The absorbance of postprandial phase was significantly increased in group 2 than group 1. There was no difference between preprandial phase and postprandial phase absorbance in group 1. Postprandial phase absorbance was significantly higher in group 2. In a comparison of bile reflux with intragastric pH during night time, there were 4 types of reflux: Simultaneous increase in absorbance and pH in only 19.6%, increase in bilirubin with unchanged pH 33.3%, pH increase with unchanged absorbance 36.3%, and both unchanged in 10.8%. Linear regression analysis showed no correlation between percentage total time of pH【4 and percentage total time of absorbance】0.14, r=0.068 P【0.05. CONCLUSION: Because of the dietary effect, high absorbance fluids or foods should be avoided in detection. Intragastric pH and bilirubin monitoring separately predict the presence of duodenal (and/or pancreatic) reflux and bile reflux. They can not substitute for each other. The detection of DGR is improved if the two parameters are combined simultaneously.展开更多
A novel polyacrylaminothiourea chelating fiber was synthesized simply andrapidly from nitrilon (an acrylonitrile-based synthetic fiber), which was applied to preconcentrateand separate of trace amount of Au(III), Pt(I...A novel polyacrylaminothiourea chelating fiber was synthesized simply andrapidly from nitrilon (an acrylonitrile-based synthetic fiber), which was applied to preconcentrateand separate of trace amount of Au(III), Pt(IV), Pd(IV) and Ir(IV) ions from solution of samples.The analyzed ions can be quantitatively concentrated by the fiber up to a flow rate of 20.0 mL/minat pH 2, and can also be desorbed with 15 mL of 4 mol/L HCl+3% thiourea from the fiber column withrecoveries of 96.5%-100%. The chelating fiber can be reused for ten times, the recoveries of theseions are still over 92%, and hundred to thousand times of excess of Fe(III), Al(III), Ca(II),Mg(II), Ni(II), Mn(II), Cu(II), Zn(II), and Cd(II) cause no interference on the determination of theanalyzed ions by inductively-coupled plasma atomic emission spectrometry (ICP-AES). The staticsaturation adsorption capacities of the fiber for the analytes are in the range of 1.15-2.80 mmol/g.The relative standard deviations for the determination of 20.0 ng/mL each of Au(III), Pt(IV),Pd(IV) and Ir(IV) are in the range of 0.7%-3.0%. The recoveries for test from standard additions toreal solution samples are between 96% and 100%. The concentration of each ion in powder sampledetected by the method is in good agreement with the certified value.展开更多
Electrochemical CO_(2)reduction is a sustainable approach in green chemistry that enables the production of valuable chemicals and fuels while mitigating the environmental impact associated with CO_(2)emissions.Despit...Electrochemical CO_(2)reduction is a sustainable approach in green chemistry that enables the production of valuable chemicals and fuels while mitigating the environmental impact associated with CO_(2)emissions.Despite its several advantages,this technology suffers from an intrinsically low CO_(2)solubility in aqueous solutions,resulting in a lower local CO_(2)concentration near the electrode,which yields lower current densities and restricts product selectivity.Gas diffusion electrodes(GDEs),particularly those with tubular architectures,can solve these issues by increasing the local CO_(2)concentration and triple-phase interface,providing abundant electroactive sites to achieve superior reaction rates.In this study,robust and self-supported Cu flow-through gas diffusion electrodes(FTGDEs)were synthesized for efficient formate production via electrochemical CO_(2)reduction.They were further compared with traditional Cu electrodes,and it was found that higher local CO_(2)concentration due to improved mass transfer,the abundant surface area available for the generation of the triple-phase interface,and the porous structure of Cu FTGDEs enabled high formate Faradaic efficiency(76%)and current density(265 mA¸cm^(−2))at–0.9 V vs.reversible hydrogen electrode(RHE)in 0.5 mol·L^(−1)KHCO3.The combined phase inversion and calcination process of the Cu FTGDEs helped maintain a stable operation for several hours.The catalytic performance of the Cu FTGDEs was further investigated in a non-gas diffusion configuration to demonstrate the impact of local gas concentration on the activity and performance of electrochemical CO_(2)reduction.This study demonstrates the potential of flow-through gas-diffusion electrodes to enhance reaction kinetics for the highly efficient and selective reduction of CO_(2),offering promising applications in sustainable electrochemical processes.展开更多
基金the Public Health Ministry Foundation of China,No.06-9602-13
文摘AIM: To assess the diagnostic value of a combination of continuous intragastric pH and bilirubin monitoring in the detection of duodenogastric reflux (DGR), and the effects of diet on the bilirubin absorbance. METHODS: 30 healthy volunteers were divided into two groups: standard diet group (Group 1) 18 cases, free diet group (Group 2)12 cases. Each subjects were subjected to simultaneous 24-hour intragastric pH and spectrophotometric bilirubin concentration monitoring (Bilitec 2000). RESULTS: There was no difference of preprandial phase bilirubin absorbance between two groups. The absorbance of postprandial phase was significantly increased in group 2 than group 1. There was no difference between preprandial phase and postprandial phase absorbance in group 1. Postprandial phase absorbance was significantly higher in group 2. In a comparison of bile reflux with intragastric pH during night time, there were 4 types of reflux: Simultaneous increase in absorbance and pH in only 19.6%, increase in bilirubin with unchanged pH 33.3%, pH increase with unchanged absorbance 36.3%, and both unchanged in 10.8%. Linear regression analysis showed no correlation between percentage total time of pH【4 and percentage total time of absorbance】0.14, r=0.068 P【0.05. CONCLUSION: Because of the dietary effect, high absorbance fluids or foods should be avoided in detection. Intragastric pH and bilirubin monitoring separately predict the presence of duodenal (and/or pancreatic) reflux and bile reflux. They can not substitute for each other. The detection of DGR is improved if the two parameters are combined simultaneously.
基金theNaturalScienceFoundationofNingxia ,China (No .199912 )andtheScienceCommitteeFoundationofNingx ia ,China
文摘A novel polyacrylaminothiourea chelating fiber was synthesized simply andrapidly from nitrilon (an acrylonitrile-based synthetic fiber), which was applied to preconcentrateand separate of trace amount of Au(III), Pt(IV), Pd(IV) and Ir(IV) ions from solution of samples.The analyzed ions can be quantitatively concentrated by the fiber up to a flow rate of 20.0 mL/minat pH 2, and can also be desorbed with 15 mL of 4 mol/L HCl+3% thiourea from the fiber column withrecoveries of 96.5%-100%. The chelating fiber can be reused for ten times, the recoveries of theseions are still over 92%, and hundred to thousand times of excess of Fe(III), Al(III), Ca(II),Mg(II), Ni(II), Mn(II), Cu(II), Zn(II), and Cd(II) cause no interference on the determination of theanalyzed ions by inductively-coupled plasma atomic emission spectrometry (ICP-AES). The staticsaturation adsorption capacities of the fiber for the analytes are in the range of 1.15-2.80 mmol/g.The relative standard deviations for the determination of 20.0 ng/mL each of Au(III), Pt(IV),Pd(IV) and Ir(IV) are in the range of 0.7%-3.0%. The recoveries for test from standard additions toreal solution samples are between 96% and 100%. The concentration of each ion in powder sampledetected by the method is in good agreement with the certified value.
基金supported by the National Key Research and Development Plan Project of China(Grant No.2018YFA0702300)the National Natural Science Foundation of China(Grant No.52227813).
文摘Electrochemical CO_(2)reduction is a sustainable approach in green chemistry that enables the production of valuable chemicals and fuels while mitigating the environmental impact associated with CO_(2)emissions.Despite its several advantages,this technology suffers from an intrinsically low CO_(2)solubility in aqueous solutions,resulting in a lower local CO_(2)concentration near the electrode,which yields lower current densities and restricts product selectivity.Gas diffusion electrodes(GDEs),particularly those with tubular architectures,can solve these issues by increasing the local CO_(2)concentration and triple-phase interface,providing abundant electroactive sites to achieve superior reaction rates.In this study,robust and self-supported Cu flow-through gas diffusion electrodes(FTGDEs)were synthesized for efficient formate production via electrochemical CO_(2)reduction.They were further compared with traditional Cu electrodes,and it was found that higher local CO_(2)concentration due to improved mass transfer,the abundant surface area available for the generation of the triple-phase interface,and the porous structure of Cu FTGDEs enabled high formate Faradaic efficiency(76%)and current density(265 mA¸cm^(−2))at–0.9 V vs.reversible hydrogen electrode(RHE)in 0.5 mol·L^(−1)KHCO3.The combined phase inversion and calcination process of the Cu FTGDEs helped maintain a stable operation for several hours.The catalytic performance of the Cu FTGDEs was further investigated in a non-gas diffusion configuration to demonstrate the impact of local gas concentration on the activity and performance of electrochemical CO_(2)reduction.This study demonstrates the potential of flow-through gas-diffusion electrodes to enhance reaction kinetics for the highly efficient and selective reduction of CO_(2),offering promising applications in sustainable electrochemical processes.
