The potent antibacterial activity of silver nanoparticles is primarily attributed to the release of silver ions,which disrupt cell membranes and inactivate essential enzymes through Ag−S bonding formation.[Objective]T...The potent antibacterial activity of silver nanoparticles is primarily attributed to the release of silver ions,which disrupt cell membranes and inactivate essential enzymes through Ag−S bonding formation.[Objective]To explore silver ion immobilization to minimize silver release.[Methods]A macrocyclic cryptand with nitrogen bridgeheads was prepared and subsequently chelated with silver ions to produce Cage silver(I),which was then coordinated with different ratios of sulfonated chitosan(SCS)to form SCS/Cage Ag(I)complexes(SCA1,SCA2,and SCA3).The antioxidant activities of the complexes were assessed by reducing power and 1,1-diphenyl-2-picrylhydrazyl(DPPH)free radical and hydrogen peroxide scavenging assays.The antibacterial activities of the complexes were evaluated based on the minimum inhibitory concentrations(MICs)and minimum bactericidal concentrations(MBCs)against Staphylococcus aureus ATCC 6538 and Escherichia coli O157:H7 and the inhibition rate on biofilm formation.[Results]Cage silver(I)exhibited strong antibacterial activity,with the MIC of 0.015 mg/mL and MBC of 0.031 mg/mL against S.aureus ATCC 6538,and the MIC of 0.031 mg/mL and MBC of 0.120 mg/mL against E.coli O157:H7.Significant antioxidant properties of Cage silver(I)were also observed,as demonstrated by the DPPH free radical scavenging rates of 42.2%and 53.1%at 326 nm and 517 nm,respectively.Cage silver(I)exhibited the highest antibacterial and antioxidant activities,followed by SCA1,SCA2,SCA3,and SCS,because the content of silver ions in Cage silver(I)was 10-fold higher than that in SCA1.The antibacterial and antioxidant activities of SCA1 were better than those of Cage silver(I),which further indicated that the sulfonic groups of SCS may intensely coordinate with silver ions to exert synergistic effects.[Conclusion]Combining the merits of silver ions and SCS improves the bioavailability of the agent at microbicidal concentrations,minimizes the accumulation in the environment,and reduces treatment costs.The method developed herein offers a sustainable approach to enhance microbial control while minimizing the impact on the environment.展开更多
[目的/意义]通过对全球智慧农业领域的研究态势进行分析,以期为当下及今后中国智慧农业领域的科技创新与管理决策提供数据参考和情报支撑。[方法/过程]基于WebofScience数据库,利用文献计量和知识图谱等方法,针对全球范围内智慧农业的...[目的/意义]通过对全球智慧农业领域的研究态势进行分析,以期为当下及今后中国智慧农业领域的科技创新与管理决策提供数据参考和情报支撑。[方法/过程]基于WebofScience数据库,利用文献计量和知识图谱等方法,针对全球范围内智慧农业的研究概况、研究群体的竞争力、研究重点与热点等进行深入分析及可视化展示。[结果/结论]2010年之后全球及中国智慧农业的研究热度越来越高;中国和美国的生产力和影响力均遥遥领先于世界其他各国,中国农业大学、浙江大学、美国农业部的生产力和影响力具有明显优势,HEY、JAYASDS、BLASCOJ的生产力和影响力均较高,中国机构和学者的论文质量普遍不高;农学、计算机科学、工程学、食品科学技术、化学是重点学科领域,Computers and Electronics in Agriculture的期刊竞争力最强;全球及中国智慧农业领域均可分为三大研究主题,但研究重点有所差异;以农业物联网为代表的信息感知、分析与调控技术是近年来的研究热点;农用传感器的自主研发、数据挖掘分析和共享利用的技术模式、智能控制的算法模型和系统集成、智能化农机装备和农业机器人自主研发、智慧化农业科技服务模式等是中国智慧农业进一步发展需要突破的重点研究方向。展开更多
文摘The potent antibacterial activity of silver nanoparticles is primarily attributed to the release of silver ions,which disrupt cell membranes and inactivate essential enzymes through Ag−S bonding formation.[Objective]To explore silver ion immobilization to minimize silver release.[Methods]A macrocyclic cryptand with nitrogen bridgeheads was prepared and subsequently chelated with silver ions to produce Cage silver(I),which was then coordinated with different ratios of sulfonated chitosan(SCS)to form SCS/Cage Ag(I)complexes(SCA1,SCA2,and SCA3).The antioxidant activities of the complexes were assessed by reducing power and 1,1-diphenyl-2-picrylhydrazyl(DPPH)free radical and hydrogen peroxide scavenging assays.The antibacterial activities of the complexes were evaluated based on the minimum inhibitory concentrations(MICs)and minimum bactericidal concentrations(MBCs)against Staphylococcus aureus ATCC 6538 and Escherichia coli O157:H7 and the inhibition rate on biofilm formation.[Results]Cage silver(I)exhibited strong antibacterial activity,with the MIC of 0.015 mg/mL and MBC of 0.031 mg/mL against S.aureus ATCC 6538,and the MIC of 0.031 mg/mL and MBC of 0.120 mg/mL against E.coli O157:H7.Significant antioxidant properties of Cage silver(I)were also observed,as demonstrated by the DPPH free radical scavenging rates of 42.2%and 53.1%at 326 nm and 517 nm,respectively.Cage silver(I)exhibited the highest antibacterial and antioxidant activities,followed by SCA1,SCA2,SCA3,and SCS,because the content of silver ions in Cage silver(I)was 10-fold higher than that in SCA1.The antibacterial and antioxidant activities of SCA1 were better than those of Cage silver(I),which further indicated that the sulfonic groups of SCS may intensely coordinate with silver ions to exert synergistic effects.[Conclusion]Combining the merits of silver ions and SCS improves the bioavailability of the agent at microbicidal concentrations,minimizes the accumulation in the environment,and reduces treatment costs.The method developed herein offers a sustainable approach to enhance microbial control while minimizing the impact on the environment.
文摘[目的/意义]通过对全球智慧农业领域的研究态势进行分析,以期为当下及今后中国智慧农业领域的科技创新与管理决策提供数据参考和情报支撑。[方法/过程]基于WebofScience数据库,利用文献计量和知识图谱等方法,针对全球范围内智慧农业的研究概况、研究群体的竞争力、研究重点与热点等进行深入分析及可视化展示。[结果/结论]2010年之后全球及中国智慧农业的研究热度越来越高;中国和美国的生产力和影响力均遥遥领先于世界其他各国,中国农业大学、浙江大学、美国农业部的生产力和影响力具有明显优势,HEY、JAYASDS、BLASCOJ的生产力和影响力均较高,中国机构和学者的论文质量普遍不高;农学、计算机科学、工程学、食品科学技术、化学是重点学科领域,Computers and Electronics in Agriculture的期刊竞争力最强;全球及中国智慧农业领域均可分为三大研究主题,但研究重点有所差异;以农业物联网为代表的信息感知、分析与调控技术是近年来的研究热点;农用传感器的自主研发、数据挖掘分析和共享利用的技术模式、智能控制的算法模型和系统集成、智能化农机装备和农业机器人自主研发、智慧化农业科技服务模式等是中国智慧农业进一步发展需要突破的重点研究方向。
