The hybrid TiO_(2)/AgNPs/g-C_(3) N_(4) nanocomposite coatings were constructed on TC4 alloy by a hydrothermal and calcining method.TiO_(2)/AgNPs/g-C_(3) N_(4) nanocomposite coatings demonstrated excellent biocompatibi...The hybrid TiO_(2)/AgNPs/g-C_(3) N_(4) nanocomposite coatings were constructed on TC4 alloy by a hydrothermal and calcining method.TiO_(2)/AgNPs/g-C_(3) N_(4) nanocomposite coatings demonstrated excellent biocompatibility and osteogenesis compared to those of titanium alloy.The existence of trace AgNPs on the surface and interface of the heterojunction could further enhance the transfer and separation of photogenerated electron/hole pairs,which greatly improved the antibacterial performance under full spectrum light.Holes at the valence band of TiO_(2) and g-C_(3) N_(4) reacted with adsorbed H_(2) O to generate·OH,killing bacteria through photocatalytic redox reaction under light irradiation,while released AgNPs exhibited bacteriostatic efficacy with or without light.This study provides a pathway of coating modification for further improving the antibacterial properties of heterojunction coatings and maintaining the biocompatibility of matrix materials.展开更多
文摘【目的】明确丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)影响玉米生育期土壤氧化亚氮(N_(2)O)排放的机制,为增加玉米产量、提高氮素利用效率、减少温室气体排放提供理论依据。【方法】采用分室(生长室和菌丝室)箱体装置,盆栽设置氮肥用量(N1:180 kg N·hm^(-2);N2:360 kg N·hm^(-2))和丛枝菌根真菌(M0:作物根和AMF均不能从生长室进入菌丝室;M1:只有丛枝菌根真菌能从生长室进入菌丝室;M2:作物根和丛枝菌根真菌均能从生长室进入菌丝室)双因素试验,测定玉米生长期间植株生物量、植株氮素积累量、N_(2)O排放量;采用Illumina平台Hiseq 2500 PE250高通量测序技术分析土壤细菌群落结构和多样性对丛枝菌根真菌的响应。【结果】氮肥用量和丛枝菌根真菌均显著影响玉米产量、植株生物量、植株氮素积累量和N_(2)O排放量。不同氮肥用量条件下接种丛枝菌根真菌均显著增加玉米籽粒产量、植株生物量和氮素积累量。与M0相比,N1条件下M1和M2处理产量均值分别增加38%和82%,地上部氮素积累量增加30%和52%,无机氮含量减少26%和65%;N2条件下M1和M2处理籽粒产量分别增加16%和48%;地上部氮素积累量增加9%和33%,无机氮含量减少34%和55%。与M0相比,N1条件下M1和M2处理N_(2)O累积排放量分别降低17%和40%,N_(2)O排放强度分别降低41%和67%;而N2条件下N_(2)O累积排放量降低26%和45%,排放强度分别降低28%和57%。NMDS分析表明,施肥和丛枝菌根真菌均对细菌群落结构有较大影响。与N1均值相比,N2处理门水平变形菌门(Proteobacteria)和芽单胞菌门(Gemmatimonadetes)相对丰度分别降低6%和15%,而放线菌门(Actinobacteria)增加32%;属水平链霉菌(Streptomyces)增加27%,芽单胞菌属(Gemmatimonas)降低8%。与M0相比,N1条件下M1和M2处理的Streptomyces分别增加64%和205%,Gemmatimonas细菌丰度分别增加31%和53%;N2条件下M1和M2处理的Streptomyces分别增加10%和93%,M1处理的Gemmatimonas细菌丰度降低2%,M2处理Gemmatimonas细菌丰度增加56%。土壤中Streptomyces和Gemmatimonas与N_(2)O排放量呈显著负相关,而与玉米产量呈显著正相关。【结论】不同氮肥水平玉米接种丛枝菌根真菌均能显著降低土壤N_(2)O排放量,这种影响主要通过提高玉米氮素的吸收利用和改善土壤细菌群落组成实现的,其中主要增加了土壤链霉菌属和芽单胞菌属的相对丰度。
基金supported by the National Natural Science Foundation of China (No. 51801164)Fundamental Research Funds for Central Universities (No. XDJK2020C005)+3 种基金Chongqing Key Laboratory fund of Soft-Matter Material Chemistry and Function Manufacturing (No. 20200006)Venture&Innovation Support Program for Chongqing Overseas Returnees (No. cx2018080)Chongqing College Student innovation and Entrepreneurship Program of Southwest University (No. 202010635076)Zeng Sumin grogram of School of Materials and Energy in Southwest University (No.zsm20201017)。
文摘The hybrid TiO_(2)/AgNPs/g-C_(3) N_(4) nanocomposite coatings were constructed on TC4 alloy by a hydrothermal and calcining method.TiO_(2)/AgNPs/g-C_(3) N_(4) nanocomposite coatings demonstrated excellent biocompatibility and osteogenesis compared to those of titanium alloy.The existence of trace AgNPs on the surface and interface of the heterojunction could further enhance the transfer and separation of photogenerated electron/hole pairs,which greatly improved the antibacterial performance under full spectrum light.Holes at the valence band of TiO_(2) and g-C_(3) N_(4) reacted with adsorbed H_(2) O to generate·OH,killing bacteria through photocatalytic redox reaction under light irradiation,while released AgNPs exhibited bacteriostatic efficacy with or without light.This study provides a pathway of coating modification for further improving the antibacterial properties of heterojunction coatings and maintaining the biocompatibility of matrix materials.
