Using 1–8 years bamboo as materials,the content of different chemical constituent was tested,and the reactive oxygen species(ROS)free radicals produced from laccase treated bamboo were detected by electron spin-reson...Using 1–8 years bamboo as materials,the content of different chemical constituent was tested,and the reactive oxygen species(ROS)free radicals produced from laccase treated bamboo were detected by electron spin-resonance(ESR)spectroscope.The wet-process particleboard was made from laccase-treated bamboo by hot pressing and board mechanical properties including internal bond strength(IB),modulus of rupture(MOR)and thickness swelling(TS)after 2-hours water absorption were tested under different conditions.Results showed that laccase mainly catalyze the bamboo components and improved the bonding strength of laccase-treated boards.By ESR measurement on each single component such as milled bamboo lignin,xylan and pore cotton treated with laccase,it was proved that laccase helped the degradation of bamboo lignin to produce ROS free radicals and could not catalyze the oxidation of cellulose and hemicelluloses.A logarithmic function relationship was found between board mechanical properties and ROS free radical level.It is optimal to using 5-year-old bamboo for high efficient utilization.The laccase treatment improves the activity of bamboo particles participating in self-adhesion reaction.展开更多
We present a protocol that combines the support vector machine(SVM)model with accurate 13C chemical shift calculations at the xOPBE/6-311+G(2d,p)level of theory,denoted as SVM-M(i.e.,SVM for magnetic property).We show...We present a protocol that combines the support vector machine(SVM)model with accurate 13C chemical shift calculations at the xOPBE/6-311+G(2d,p)level of theory,denoted as SVM-M(i.e.,SVM for magnetic property).We show here that this SVM-M protocol is a versatile tool for identifying the structural and stereochemical assignment of complex organic compounds with high confidence.Of particular significance is that,by utilizing the dual role of the decision values in SVM,the present SVM-M protocol provides an accurate yet efficient solution to simultaneously handle the classification issue(i.e.,“is a given structure correct or incorrect?”)and the comparison-based problem(i.e.,“which structure is more likely to be correct or wrong among several candidate structures?”).A significantly high success rate has been reached(i.e.,∼100%on a set of 760 sample molecules with 1592813C chemical shifts),which makes the SVMM protocol a powerful tool for routine applications in structural and stereochemical assignments,as well as in detecting misassignments,for complex organic compounds,including natural products.展开更多
基金The authors thank Zhejiang Provincial Science and Technology Department Project(2019F1065-4)&Zhejiang Provincial Natural Science Foundation(LY19C160004)&Public Welfare Technology Research Agricultural Project of Zhejiang Province(2013C32104)for their financial contributions.
文摘Using 1–8 years bamboo as materials,the content of different chemical constituent was tested,and the reactive oxygen species(ROS)free radicals produced from laccase treated bamboo were detected by electron spin-resonance(ESR)spectroscope.The wet-process particleboard was made from laccase-treated bamboo by hot pressing and board mechanical properties including internal bond strength(IB),modulus of rupture(MOR)and thickness swelling(TS)after 2-hours water absorption were tested under different conditions.Results showed that laccase mainly catalyze the bamboo components and improved the bonding strength of laccase-treated boards.By ESR measurement on each single component such as milled bamboo lignin,xylan and pore cotton treated with laccase,it was proved that laccase helped the degradation of bamboo lignin to produce ROS free radicals and could not catalyze the oxidation of cellulose and hemicelluloses.A logarithmic function relationship was found between board mechanical properties and ROS free radical level.It is optimal to using 5-year-old bamboo for high efficient utilization.The laccase treatment improves the activity of bamboo particles participating in self-adhesion reaction.
基金National Natural Science Foundation of China(NSFC)(22233002,21991130,21773193)Natural Science Foundation of Fujian Province of China(2021J01020)Innovation Program for Quantum Science and Technology(2021ZD0303305).
文摘We present a protocol that combines the support vector machine(SVM)model with accurate 13C chemical shift calculations at the xOPBE/6-311+G(2d,p)level of theory,denoted as SVM-M(i.e.,SVM for magnetic property).We show here that this SVM-M protocol is a versatile tool for identifying the structural and stereochemical assignment of complex organic compounds with high confidence.Of particular significance is that,by utilizing the dual role of the decision values in SVM,the present SVM-M protocol provides an accurate yet efficient solution to simultaneously handle the classification issue(i.e.,“is a given structure correct or incorrect?”)and the comparison-based problem(i.e.,“which structure is more likely to be correct or wrong among several candidate structures?”).A significantly high success rate has been reached(i.e.,∼100%on a set of 760 sample molecules with 1592813C chemical shifts),which makes the SVMM protocol a powerful tool for routine applications in structural and stereochemical assignments,as well as in detecting misassignments,for complex organic compounds,including natural products.
