It is reported that alkali-metal borohydrides （MBH4, M = Li, Na and K） are efficient catalysts for ring opening polymerization （ROP） of α-amino acid N-carboxyanhydrides （NCAs）. Polypeptides are prepared in quan...It is reported that alkali-metal borohydrides （MBH4, M = Li, Na and K） are efficient catalysts for ring opening polymerization （ROP） of α-amino acid N-carboxyanhydrides （NCAs）. Polypeptides are prepared in quantitative yields with relatively narrow molecular weight distributions （MWDs = 1.1-1.5） which depend on the reaction temperature. End groups of the produced polypeptide are studied in detail by MALDI-ToF MS, IH-NMR, 13C-NMR, IH-1H COSY and IH-13C HMQC analyses. The results indicate that α-hydroxy-ω-aminotelechelic polypeptides are formed which are suitable for post- polymerization functionalization.展开更多
Polypeptide brushes are attractive platforms to generate functional and responsive interfaces that are of potential interest due to their possible biodegradability, biocompatibility and tunable secondary structures. S...Polypeptide brushes are attractive platforms to generate functional and responsive interfaces that are of potential interest due to their possible biodegradability, biocompatibility and tunable secondary structures. Surface-initiated ringopening polymerization（SI-ROP） of α-amino acid N-carboxyanhydrides represents a powerful and versatile strategy to generate polypeptide brushes. This review is an attempt to capture the state-of-the-art in this field and highlights the latest developments in several selected areas. In addition to presenting an overview of the synthetic methods that have been used to generate polypeptide brushes via SI-ROP, this article will discuss the preparation of patterned polypeptide brushes, the conformational properties of surface-tethered polypeptides, ways to control chain orientation at surfaces as well as properties and applications of these thin polymer films.展开更多
利用FACE(Free Air Carbon-dioxide Enrichment)平台技术,研究了低氮(LN150kg·hm-2)和常氮(NN250kg·hm-2)水平下,大气CO2浓度升高对水稻(OryzasativaL.)体内不同形态N素含量的影响。结果表明,CO2浓度升高促进了水稻茎、穗和...利用FACE(Free Air Carbon-dioxide Enrichment)平台技术,研究了低氮(LN150kg·hm-2)和常氮(NN250kg·hm-2)水平下,大气CO2浓度升高对水稻(OryzasativaL.)体内不同形态N素含量的影响。结果表明,CO2浓度升高促进了水稻茎、穗和根的生长而使水稻的总生物量显著增加;同时显著降低分蘖期根、茎、叶,抽穗期茎和成熟期叶、根中的N含量,而其降低量的50%￣181.8%归因于蛋白态N含量的降低,因此蛋白态N含量的降低是N含量下降的直接原因。此外,CO2浓度升高使整个生育期内水稻不同部位氨基酸态N含量普遍降低,而无机态N含量随生育期和植株部位不同的表现为降低或者升高,这可能是根系的N同化能力改变的结果。还讨论了高浓度CO2条件下水稻组织中蛋白态N含量降低的原因。展开更多
基金financially supported by the National Natural Science Foundation of China(No.21174122)Special Funds for Major Basic Research Projects(No.G2011CB606001)Zhejiang Provincial Natural Science Foundation of China(No.Y4110115)
文摘It is reported that alkali-metal borohydrides （MBH4, M = Li, Na and K） are efficient catalysts for ring opening polymerization （ROP） of α-amino acid N-carboxyanhydrides （NCAs）. Polypeptides are prepared in quantitative yields with relatively narrow molecular weight distributions （MWDs = 1.1-1.5） which depend on the reaction temperature. End groups of the produced polypeptide are studied in detail by MALDI-ToF MS, IH-NMR, 13C-NMR, IH-1H COSY and IH-13C HMQC analyses. The results indicate that α-hydroxy-ω-aminotelechelic polypeptides are formed which are suitable for post- polymerization functionalization.
基金financially supported by the Sino-Swiss Science and Technology Cooperation(No.EG41-092011)as well as the Chinese Academy of Sciences(Visiting Professorship for Senior International Scientists to H.A.K.)
文摘Polypeptide brushes are attractive platforms to generate functional and responsive interfaces that are of potential interest due to their possible biodegradability, biocompatibility and tunable secondary structures. Surface-initiated ringopening polymerization（SI-ROP） of α-amino acid N-carboxyanhydrides represents a powerful and versatile strategy to generate polypeptide brushes. This review is an attempt to capture the state-of-the-art in this field and highlights the latest developments in several selected areas. In addition to presenting an overview of the synthetic methods that have been used to generate polypeptide brushes via SI-ROP, this article will discuss the preparation of patterned polypeptide brushes, the conformational properties of surface-tethered polypeptides, ways to control chain orientation at surfaces as well as properties and applications of these thin polymer films.
文摘利用FACE(Free Air Carbon-dioxide Enrichment)平台技术,研究了低氮(LN150kg·hm-2)和常氮(NN250kg·hm-2)水平下,大气CO2浓度升高对水稻(OryzasativaL.)体内不同形态N素含量的影响。结果表明,CO2浓度升高促进了水稻茎、穗和根的生长而使水稻的总生物量显著增加;同时显著降低分蘖期根、茎、叶,抽穗期茎和成熟期叶、根中的N含量,而其降低量的50%￣181.8%归因于蛋白态N含量的降低,因此蛋白态N含量的降低是N含量下降的直接原因。此外,CO2浓度升高使整个生育期内水稻不同部位氨基酸态N含量普遍降低,而无机态N含量随生育期和植株部位不同的表现为降低或者升高,这可能是根系的N同化能力改变的结果。还讨论了高浓度CO2条件下水稻组织中蛋白态N含量降低的原因。
