AIM: To investigate the usefulness of chromoendoscopy, using an acetic acid indigocarmine mixture (AIM), for gastric adenoma diagnosed by forceps biopsy.
Poplar wood chips were extracted in an acetic acid/sodium acetate(SA/AA)buffer solution at 180ºC for 60 minutes,with a solid-to-liquid ratio of 1:6,to investigate the effect of pH on the extraction performance in...Poplar wood chips were extracted in an acetic acid/sodium acetate(SA/AA)buffer solution at 180ºC for 60 minutes,with a solid-to-liquid ratio of 1:6,to investigate the effect of pH on the extraction performance in terms of chemical compositions of the extract.The pH was controlled by varying the concentrations of sodium acetate and acetic acid in the buffer system.Results showed that the SA/AA system could promote the dissolution of hemicellulose,obtaining more oligosaccharides and monosaccharides,and could also inhibit the excessive decomposition of monosaccharides.When extracting poplar wood chips in a SA/AA system of pH=3.7,the yield of oligosaccharides was the highest,while the contents of furfural and hydroxymethyl furfural decreased by 25%and 30%,respectively,compared to conventional water extraction systems.Moreover,the amount of lignin extracted in the S/AA process was also higher than that in a conventional hot water extraction process.展开更多
Hydrothermal pretreatment of poplar wood chips was performed in an acetic acid/sodium acetate buffer medium.To characterize the structural changes of lignin in the pretreatment process,milled wood lignin(MWL)was isola...Hydrothermal pretreatment of poplar wood chips was performed in an acetic acid/sodium acetate buffer medium.To characterize the structural changes of lignin in the pretreatment process,milled wood lignin(MWL)was isolated from both the un-treated and treated poplar wood chips,and analyzed by ^(1)H-NMR,^(13)C-NMR,^(31)P-NMR,FT-IR,and GPC-MALLS.Results showed that the lignin in the pretreated wood chips had more phenolic OH groups,less aliphatic OH groups,higher molecular weight,and narrower polydispersity,in comparison with the lignin in the un-treated wood.The acetic acid-sodium acetate buffer pretreatment facilitated the removal of-OCH_(3) groups and the cleavage of the inter-unit linkages ofβ-O-4 bond in the lignin.Furthermore,the re-polymerization of lignin in the acetic acid-sodium acetate buffer pretreatment was found to be less than that in autohydrolysis.展开更多
文摘AIM: To investigate the usefulness of chromoendoscopy, using an acetic acid indigocarmine mixture (AIM), for gastric adenoma diagnosed by forceps biopsy.
基金the National Natural Science Foundation of China(31540009 and 31370581)the Independent Innovation and Achievements Transformation Project of Shandong Province(2014CGZH0302)the Yellow River Mouth Scholar Program(DYRC20120105).
文摘Poplar wood chips were extracted in an acetic acid/sodium acetate(SA/AA)buffer solution at 180ºC for 60 minutes,with a solid-to-liquid ratio of 1:6,to investigate the effect of pH on the extraction performance in terms of chemical compositions of the extract.The pH was controlled by varying the concentrations of sodium acetate and acetic acid in the buffer system.Results showed that the SA/AA system could promote the dissolution of hemicellulose,obtaining more oligosaccharides and monosaccharides,and could also inhibit the excessive decomposition of monosaccharides.When extracting poplar wood chips in a SA/AA system of pH=3.7,the yield of oligosaccharides was the highest,while the contents of furfural and hydroxymethyl furfural decreased by 25%and 30%,respectively,compared to conventional water extraction systems.Moreover,the amount of lignin extracted in the S/AA process was also higher than that in a conventional hot water extraction process.
基金support from the National Natural Science Foundation of China (31540009 and 31370581)the Yellow River Mouth Scholar Program (DYRC20120105).
文摘Hydrothermal pretreatment of poplar wood chips was performed in an acetic acid/sodium acetate buffer medium.To characterize the structural changes of lignin in the pretreatment process,milled wood lignin(MWL)was isolated from both the un-treated and treated poplar wood chips,and analyzed by ^(1)H-NMR,^(13)C-NMR,^(31)P-NMR,FT-IR,and GPC-MALLS.Results showed that the lignin in the pretreated wood chips had more phenolic OH groups,less aliphatic OH groups,higher molecular weight,and narrower polydispersity,in comparison with the lignin in the un-treated wood.The acetic acid-sodium acetate buffer pretreatment facilitated the removal of-OCH_(3) groups and the cleavage of the inter-unit linkages ofβ-O-4 bond in the lignin.Furthermore,the re-polymerization of lignin in the acetic acid-sodium acetate buffer pretreatment was found to be less than that in autohydrolysis.
