The redox-sensitive elements,such as iron,manganese,sulfur,phosphorus,and arsenic,shift their speciation every millimeter(mm)across the soil-water interface in the flooded soil environments.Monitoring of element speci...The redox-sensitive elements,such as iron,manganese,sulfur,phosphorus,and arsenic,shift their speciation every millimeter(mm)across the soil-water interface in the flooded soil environments.Monitoring of element speciation at this high-resolution(HR)within the SWI is still difficult.The key challenge lies in obtaining sufficient porewater samples at specific locations along the soil gradient for downstream analysis.Here with an optimized inductively coupled plasma mass spectrometry(ICP-MS)method and a HR porewater sampler,we demonstrate mm-scale element profiles mapping across the SWI in paddy soils.Highconcentrations of iron and manganese(>10 mg/L)were measured by ICP-MS in an extended dynamic range mode to avoid signal overflow.The iron profile along the SWI generated by the ICP-MS method showed no significant difference(p<0.05)compared to that measured independently using a colorimetric method.Furthermore,four arsenic(arsenite,arsenate,monomethylarsonic and dimethylarsinic acid),two phosphorus(phosphite and phosphate)and two sulfur(sulfide and sulfate)species were separated in 10 min by ion chromatography-ICP-MS with the NH_(4)HCO_(3)mobile phase.We verified the technique using paddy soils collected from the field,and present the mm-scale profiles of iron,manganese,and arsenic,phosphorus,sulfur species(relative standard deviation<8%).The technique developed in this study will significantly promote the measurement throughput in limited samples(e.g.100μL)collected by HR samplers,which would greatly facilitate redox-sensitive elements biogeochemical cycling in saturated soils.展开更多
文摘背景中国幽门螺杆菌(Helicobacter pylori,H.pylori)耐药日趋严重,已成为阻碍经验性治疗方案根除效果的主要原因之一.不同地区耐药谱不完全相同,这对经验性根除方案的推广提出了更大挑战.目的通过Meta分析对中国各地区H.pylori耐药情况进行系统评价.方法计算机全面检索PubMed、EMBASE、Web of Science、Sinomed、中国知网、万方数据库和维普数据库,收集有关中国各地区H.pylori耐药情况的横断面研究.由2名研究者独立筛选文献、提取文献数据并评价文献质量.采用R 4.3.1软件对各抗生素及其组合耐药率进行Meta分析.结果共纳入符合条件的文献46篇.全国克拉霉素(clarithromycin,CLA)、左氧氟沙星(levofloxacin,LEV)、阿莫西林(amoxicillin,AMX)、四环素(tetracycline,TET)、甲硝唑(metronidazole,MNZ)和呋喃唑酮(furazolidone,FZD)耐药率分别为27.72%(23.80%-31.82%)、31.23%(26.62%-36.02%)、3.97%(1.96%-6.65%)、4.01%(1.36%-7.98%)、75.30%(70.31%-79.97%)和0.64%(0.13%-1.53%).AMX耐药率在全国不同地区间存在显著差异,华南地区最高(7.15%,95%CI:6.16%-76.10%),华北地区最低(1.86%,95%CI:0.67%-3.64%).华东和华中CLA、华东和西北LEV、华北和西南MNZ耐药均随时间推移均显著增长,而华东地区AMX和TET耐药率显著降低.全国CLA+MNZ、LEV+MNZ和CLA+LEV双重耐药率分别达14.05%、15.12%(11.53%-19.10%)和5.16%(2.87%-8.06%),全国CLA+LEV+MNZ、LEV+MNZ+AMX和CLA+MNZ+AMX三重耐药率分别为10.36%(7.45%-13.69%)、0.92%(0.12%-2.44%)和0.85%(0.20%-1.92%).结论中国H.pylori耐药情况较为严峻,其中MNZ耐药率最高,CLA和LEV耐药次之,且部分多重耐药检出率也已达到较高水平.全国不同地区耐药情况存在一定差异,并大多随时间推移呈升高趋势.
基金supported by the National Science Foundation of China(Nos.41977320,41571305)Key Programme Special Fund of XJTLU(No.KSF-A-20)。
文摘The redox-sensitive elements,such as iron,manganese,sulfur,phosphorus,and arsenic,shift their speciation every millimeter(mm)across the soil-water interface in the flooded soil environments.Monitoring of element speciation at this high-resolution(HR)within the SWI is still difficult.The key challenge lies in obtaining sufficient porewater samples at specific locations along the soil gradient for downstream analysis.Here with an optimized inductively coupled plasma mass spectrometry(ICP-MS)method and a HR porewater sampler,we demonstrate mm-scale element profiles mapping across the SWI in paddy soils.Highconcentrations of iron and manganese(>10 mg/L)were measured by ICP-MS in an extended dynamic range mode to avoid signal overflow.The iron profile along the SWI generated by the ICP-MS method showed no significant difference(p<0.05)compared to that measured independently using a colorimetric method.Furthermore,four arsenic(arsenite,arsenate,monomethylarsonic and dimethylarsinic acid),two phosphorus(phosphite and phosphate)and two sulfur(sulfide and sulfate)species were separated in 10 min by ion chromatography-ICP-MS with the NH_(4)HCO_(3)mobile phase.We verified the technique using paddy soils collected from the field,and present the mm-scale profiles of iron,manganese,and arsenic,phosphorus,sulfur species(relative standard deviation<8%).The technique developed in this study will significantly promote the measurement throughput in limited samples(e.g.100μL)collected by HR samplers,which would greatly facilitate redox-sensitive elements biogeochemical cycling in saturated soils.
