In this study,a novel iron-based catalyst system,Fe(acac)3/(isocyanoimino)triptenylphosphorane(IITP)/AlR3,was employed for the synthesis of syndiotactic 1,2-polybutadiene in hexane.This catalyst system exhibits remark...In this study,a novel iron-based catalyst system,Fe(acac)3/(isocyanoimino)triptenylphosphorane(IITP)/AlR3,was employed for the synthesis of syndiotactic 1,2-polybutadiene in hexane.This catalyst system exhibits remarkably high catalytic activity,achieving a polymerization activity of 762 kgpolymer·molcatalyst^(-1)·h^(-1)at 50℃with a[BD]/[Fe]molar ratio of 20000.Furthermore,living polymerization characteristic were observed during the investigation of the polymerization kinetics of 1,3-butadiene polymerization.These characteristics were well demonstrated by a narrow molecular weight distribution(PDI≈2.0)of the resulting polybutadiene and a linear relationship between-ln(1-c)and polymerization time as well as number average molecular weight and polymer yield.The resultant polymer showed a 1,2-selectivity of approximately 76%and stereoregularity ranging from 62%to 73%(rrrr).Additionally,through kinetic studies on polymerization reaction,an apparent activation energy Ea value of this catalytic system was calculated to be 84.98 kJ·mol^(-1),which suggests that high polymerization temperature favors efficient polymerization.展开更多
Lipocalins exhibit functional diversity,including roles in retinol transport,invertebrate cryptic coloration,and stress response.However,genome-wide identification and characterization of lipocalin in the insect linea...Lipocalins exhibit functional diversity,including roles in retinol transport,invertebrate cryptic coloration,and stress response.However,genome-wide identification and characterization of lipocalin in the insect lineage have not been thoroughly explored.Here,we found that a lineage-specific expansion of the lipocalin genes in Lepidoptera occurred in large part due to tandem duplication events and several lipocalin genes involving insect coloration were expanded more via tandem duplication in butterflies.A comparative analysis of conserved motifs showed both conservation and divergence of lepidopteran lipocalin family protein structures during evolution.We observe dynamic changes in tissue expression preference of paralogs in Bombyx mori,suggesting differential contribution of paralogs to specific organ functions during evolution.Subcellular localization experiments revealed that lipocalins localize to the cytoplasm,nuclear membrane,or nucleus in BmN cells.Moreover,several lipocalin genes exhibited divergent responses to abiotic and biotic stresses,and 1 lipocalin gene was upregulated by 30o fold in B.mori.These results suggest that lipocalins act as signaling components in defense responses by mediating crosstalk between abiotic and biotic stress responses.This study deepens our understanding of the comprehensive characteristics of lipocalins in insects.展开更多
基金This work was financially supported by the National Key R&D Program of China(No.2022YFB3704700).
文摘In this study,a novel iron-based catalyst system,Fe(acac)3/(isocyanoimino)triptenylphosphorane(IITP)/AlR3,was employed for the synthesis of syndiotactic 1,2-polybutadiene in hexane.This catalyst system exhibits remarkably high catalytic activity,achieving a polymerization activity of 762 kgpolymer·molcatalyst^(-1)·h^(-1)at 50℃with a[BD]/[Fe]molar ratio of 20000.Furthermore,living polymerization characteristic were observed during the investigation of the polymerization kinetics of 1,3-butadiene polymerization.These characteristics were well demonstrated by a narrow molecular weight distribution(PDI≈2.0)of the resulting polybutadiene and a linear relationship between-ln(1-c)and polymerization time as well as number average molecular weight and polymer yield.The resultant polymer showed a 1,2-selectivity of approximately 76%and stereoregularity ranging from 62%to 73%(rrrr).Additionally,through kinetic studies on polymerization reaction,an apparent activation energy Ea value of this catalytic system was calculated to be 84.98 kJ·mol^(-1),which suggests that high polymerization temperature favors efficient polymerization.
基金supported by the National Natural Science Foundation of China(grant no.31970460,32170483)the Natural Science Foundation of Zhejiang Province(grant no.LR22C040001)+1 种基金the Zhejiang Provincial Science and Technology Plans(2021C02072-6)the Zhejiang Provincial Key Laboratory Construction Plans(2020E10025).
文摘Lipocalins exhibit functional diversity,including roles in retinol transport,invertebrate cryptic coloration,and stress response.However,genome-wide identification and characterization of lipocalin in the insect lineage have not been thoroughly explored.Here,we found that a lineage-specific expansion of the lipocalin genes in Lepidoptera occurred in large part due to tandem duplication events and several lipocalin genes involving insect coloration were expanded more via tandem duplication in butterflies.A comparative analysis of conserved motifs showed both conservation and divergence of lepidopteran lipocalin family protein structures during evolution.We observe dynamic changes in tissue expression preference of paralogs in Bombyx mori,suggesting differential contribution of paralogs to specific organ functions during evolution.Subcellular localization experiments revealed that lipocalins localize to the cytoplasm,nuclear membrane,or nucleus in BmN cells.Moreover,several lipocalin genes exhibited divergent responses to abiotic and biotic stresses,and 1 lipocalin gene was upregulated by 30o fold in B.mori.These results suggest that lipocalins act as signaling components in defense responses by mediating crosstalk between abiotic and biotic stress responses.This study deepens our understanding of the comprehensive characteristics of lipocalins in insects.