Two series of Mn/beta and Mn/ZSM‐5catalysts were prepared to study the influence of how different Mn precursors,introduced to the respective parent zeolites by wet impregnation,affected the selective catalytic reduct...Two series of Mn/beta and Mn/ZSM‐5catalysts were prepared to study the influence of how different Mn precursors,introduced to the respective parent zeolites by wet impregnation,affected the selective catalytic reduction(SCR)of NO by NH3across a low reaction temperature window of50–350°C.In this study,the catalysts were characterized using N2adsorption/desorption,X‐ray diffraction,X‐ray fluorescence,H2temperature‐programmed reduction,NH3temperature‐programmed desorption and X‐ray photoelectron spectroscopy.As the manganese chloride precursor only partially decomposed this primarily resulted in the formation of MnCl2in addition to the presence of low levels of crystalline Mn3O4,which resulted in poor catalytic performance.However,the manganese nitrate precursor formed crystalline MnO2as the major phase in addition to a minor presence of unconverted Mn‐nitrate.Furthermore,manganese acetate resulted principally in a mixture of amorphous Mn2O3and MnO2,and crystalline Mn3O4.From all the catalysts screened,the test performance data showed Mn/beta‐Ac to exhibit the highest NO conversion(97.5%)at240°C,which remained>90%across a temperature window of220–350°C.The excellent catalytic performance was ascribed to the enrichment of highly dispersed MnOx(Mn2O3and MnO2)species that act as the active phase in the NH3‐SCR process.Furthermore,together with a suitable amount of weakly acidic centers,higher concentration of surface manganese and a greater presence of surface labile oxygen groups,SCR performance was collectively enhanced at low temperature.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.展开更多
Background:Pancreatic neuroendocrine tumors(pNETs)with synchronous liver metastasis(NELM)are associated with poor prognosis.Radical surgery is the only curative treatment option for these patients.However,the prognost...Background:Pancreatic neuroendocrine tumors(pNETs)with synchronous liver metastasis(NELM)are associated with poor prognosis.Radical surgery is the only curative treatment option for these patients.However,the prognostic indicators for NELM patients who underwent radical surgery remain unclear.This study aimed to evaluate the prognostic value of liver metastasis burden(LMB)and other general clinicopathological indicators in patients who underwent radical resection.Methods:A retrospective analysis was conducted on a cohort of 36 patients who underwent surgery between January 2016 and December 2023.The LMB indicator was defined as the ratio of metastatic volume to liver volume(RML).The optimal cutoff value of RML was identified via X-tile software,dividing the population into high and low groups.Results:Kaplan-Meier(KM)curves for progression-free survival(PFS)revealed a significant difference between high and low groups of RML(P=.004),but there were no statistical differences in overall survival(OS)between the 2 groups(P=.309).Cox regression univariable analysis indicated that only high RML was associated with poor PFS(hazard ratio=4.42,95%confidence interval=1.48–13.22;P=.008).However,it was not significantly associated with OS(P=.331).High RML emerged as an independent risk factor for PFS in these patients(hazard ratio=4.73,95%confidence interval=1.59–14.03;P=.005).In the high RML group,patients receiving preoperative chemotherapy or chemotherapy plus somatostatin analogs(SSA),had lower recurrence rates compared with those without chemotherapy or without chemotherapy plus SSA,respectively.No such benefit was observed in the low RML group.Conclusion:RML may serve as an effective prognostic indicator of PFS for patients with NELM who undergo curative surgery.For these patients with high liver metastatic burden,preoperative treatment regimens containing chemotherapy should be recommended.展开更多
基金supported by the National Science and Technology Program of China(CDGC01-KT16)~~
文摘Two series of Mn/beta and Mn/ZSM‐5catalysts were prepared to study the influence of how different Mn precursors,introduced to the respective parent zeolites by wet impregnation,affected the selective catalytic reduction(SCR)of NO by NH3across a low reaction temperature window of50–350°C.In this study,the catalysts were characterized using N2adsorption/desorption,X‐ray diffraction,X‐ray fluorescence,H2temperature‐programmed reduction,NH3temperature‐programmed desorption and X‐ray photoelectron spectroscopy.As the manganese chloride precursor only partially decomposed this primarily resulted in the formation of MnCl2in addition to the presence of low levels of crystalline Mn3O4,which resulted in poor catalytic performance.However,the manganese nitrate precursor formed crystalline MnO2as the major phase in addition to a minor presence of unconverted Mn‐nitrate.Furthermore,manganese acetate resulted principally in a mixture of amorphous Mn2O3and MnO2,and crystalline Mn3O4.From all the catalysts screened,the test performance data showed Mn/beta‐Ac to exhibit the highest NO conversion(97.5%)at240°C,which remained>90%across a temperature window of220–350°C.The excellent catalytic performance was ascribed to the enrichment of highly dispersed MnOx(Mn2O3and MnO2)species that act as the active phase in the NH3‐SCR process.Furthermore,together with a suitable amount of weakly acidic centers,higher concentration of surface manganese and a greater presence of surface labile oxygen groups,SCR performance was collectively enhanced at low temperature.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.
基金supported by grants from the National Natural Science Foundation of China(grant no.81672862)the Beijing Xisike Clinical Oncology Research Foundation(grant no.Y-Young2021-0116)the Clinical key project of Peking University Third Hospital(grant no.BYSY2021017).
文摘Background:Pancreatic neuroendocrine tumors(pNETs)with synchronous liver metastasis(NELM)are associated with poor prognosis.Radical surgery is the only curative treatment option for these patients.However,the prognostic indicators for NELM patients who underwent radical surgery remain unclear.This study aimed to evaluate the prognostic value of liver metastasis burden(LMB)and other general clinicopathological indicators in patients who underwent radical resection.Methods:A retrospective analysis was conducted on a cohort of 36 patients who underwent surgery between January 2016 and December 2023.The LMB indicator was defined as the ratio of metastatic volume to liver volume(RML).The optimal cutoff value of RML was identified via X-tile software,dividing the population into high and low groups.Results:Kaplan-Meier(KM)curves for progression-free survival(PFS)revealed a significant difference between high and low groups of RML(P=.004),but there were no statistical differences in overall survival(OS)between the 2 groups(P=.309).Cox regression univariable analysis indicated that only high RML was associated with poor PFS(hazard ratio=4.42,95%confidence interval=1.48–13.22;P=.008).However,it was not significantly associated with OS(P=.331).High RML emerged as an independent risk factor for PFS in these patients(hazard ratio=4.73,95%confidence interval=1.59–14.03;P=.005).In the high RML group,patients receiving preoperative chemotherapy or chemotherapy plus somatostatin analogs(SSA),had lower recurrence rates compared with those without chemotherapy or without chemotherapy plus SSA,respectively.No such benefit was observed in the low RML group.Conclusion:RML may serve as an effective prognostic indicator of PFS for patients with NELM who undergo curative surgery.For these patients with high liver metastatic burden,preoperative treatment regimens containing chemotherapy should be recommended.
