A nitrile hydratase (NHase) hyper-producing Rhodococcus ruber strain LUV30-06 was bred by mutagenization on the starting strain CGMCC3090 with ultraviolet irradiation and lithium chloride. The NHase activity of the st...A nitrile hydratase (NHase) hyper-producing Rhodococcus ruber strain LUV30-06 was bred by mutagenization on the starting strain CGMCC3090 with ultraviolet irradiation and lithium chloride. The NHase activity of the strain LUV30-06 was increased by 21.99% (3881.3 U/ml), as compared with that of R. ruber CGMCC3090 (3181.4 U/ml). The mutant strain UV30-06 has been proved genetically stable with higher NHase activity in seven successive subcultures as well as random amplified polymorphic DNA analysis (RAPD).展开更多
Conventional fluorescent polymers are featured by large conjugation structures.In contrast,a new class of fluorescent polymers without any conjugations is gaining great interest in immerging applications.Polyamide is ...Conventional fluorescent polymers are featured by large conjugation structures.In contrast,a new class of fluorescent polymers without any conjugations is gaining great interest in immerging applications.Polyamide is a typical member of the conjugation-free fluorescent polymers.However,studies on their electrophotonic property are hardly available,although widely used in many fields.Herein,poly(ethylene succinamide),PA24,is synthesized;its chemical structure confirmed through multiple techniques(NMR,FTIR,XRD,etc.).PA24 is highly emissive as solid and in its solution at room temperature,and the emission is excitation and concentration dependant,with an unusual blue shift under excitation from 270 nm to 320 nm,a hardly observed phenomenon for all fluorescent polymers.Quite similar emission behavior is also observed under cryogenic condition at 77 K.Its emission behavior is thoroughly studied;the ephemeral emission blue-shift is interpreted through Förster resonance energy transfer.Based on its structures,the emission mechanism is ascribed to cluster-triggered emission,elucidated from multianalyses(NMR,FTIR,UV absorbance and DLS).In presence of a dozen of competitive metal ions,PA24 emission at 450 nm is selectively quenched by Fe^(3+).PA24 is used as probe for Fe^(3+)and H_(2)O_(2) detections and in data encryption.Therefore,this work provides a novel face of polyamide with great potential applications as sensors in different fields.展开更多
This study carries out a simulated experiment of biogenic gas generation and studies the effects of gas generation on the pore structure and molecular structure of anthracite by mercury intrusion porosimetry,X-ray dif...This study carries out a simulated experiment of biogenic gas generation and studies the effects of gas generation on the pore structure and molecular structure of anthracite by mercury intrusion porosimetry,X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FT-IR).The results show that methanogenic bacteria can produce biogenic gas from anthracite.CO_(2) and CH4 are the main components of the generated biogas.After generation,some micropores(<10 nm)and transitional pores(10–100 nm)in the coal samples transform into large pores.In the high-pressure stage(pressure>100 MPa)of the mercury intrusion test,the specific surface area decreases by 19.79%compared with that of raw coal,and the pore volume increases by 7.25%in total.Microbial action on the molecular structure causes changes in the pore reconstruction.The FT-IR data show that the side chains and hydroxyl groups of the coal molecular structure in coal are easily metabolized by methanogenic bacteria and partially oxidized to form carboxylic acids.In addition,based on the XRD data,the aromatic lamellar structure in the coal is changed by microorganisms;it decreases in lateral size(La)and stacking thickness(Lc).This study enriches the theory of biogenic coalbed gas generation and provides a pathway for enhancing the permeability of high-rank coal reservoirs.展开更多
Rural settlements serve as an important part of the rural landscape,and environmental conditions influence their spatial distribution.We hypothesize that there are variations in the spatial patterns of settlements acr...Rural settlements serve as an important part of the rural landscape,and environmental conditions influence their spatial distribution.We hypothesize that there are variations in the spatial patterns of settlements across different farming–pastoral ecotones that exist in accordance with different human activities and environmental conditions.We used remote sensing imagery,digital elevation model,and GIS technology to analyze and compare the spatial patterns of settlements and factors influencing these patterns across pastoral,agricultural,and ecotone areas in Inner Mongolia,China.A Voronoi model,adjacency analysis,landscape metrics,and quantitative analysis were conducted.The results indicated that(1)the settlements in the three areas tended to have a random spatial distribution,and although there were no significant differences between the settlement types,agricultural settlements tended to be clustered and pastoral settlements tended to be evenly distributed;(2)the pastoral area had only a few large and sparsely fragmented patches;(3)the factors influencing settlement distribution mainly differed with respect to the NDVI,distance to roads and rivers,and elevation across three areas,but the slope degree was similar.These results indicated there are no significant differences between the spatial patterns of settlements along the agricultural to pastoral gradient,although environmental conditions differ.Consequently,we can optimize the spatial pattern of settlements and achieve sustainable development within farming–pastoral ecotones.展开更多
文摘A nitrile hydratase (NHase) hyper-producing Rhodococcus ruber strain LUV30-06 was bred by mutagenization on the starting strain CGMCC3090 with ultraviolet irradiation and lithium chloride. The NHase activity of the strain LUV30-06 was increased by 21.99% (3881.3 U/ml), as compared with that of R. ruber CGMCC3090 (3181.4 U/ml). The mutant strain UV30-06 has been proved genetically stable with higher NHase activity in seven successive subcultures as well as random amplified polymorphic DNA analysis (RAPD).
基金Natural Science Foundation of Shandong Province(Nos.ZR2019MB031 and ZR2021MB112)Science and Technology Bureau of Jinan city(No.2021GXRC105),Shandong Province,China.
文摘Conventional fluorescent polymers are featured by large conjugation structures.In contrast,a new class of fluorescent polymers without any conjugations is gaining great interest in immerging applications.Polyamide is a typical member of the conjugation-free fluorescent polymers.However,studies on their electrophotonic property are hardly available,although widely used in many fields.Herein,poly(ethylene succinamide),PA24,is synthesized;its chemical structure confirmed through multiple techniques(NMR,FTIR,XRD,etc.).PA24 is highly emissive as solid and in its solution at room temperature,and the emission is excitation and concentration dependant,with an unusual blue shift under excitation from 270 nm to 320 nm,a hardly observed phenomenon for all fluorescent polymers.Quite similar emission behavior is also observed under cryogenic condition at 77 K.Its emission behavior is thoroughly studied;the ephemeral emission blue-shift is interpreted through Förster resonance energy transfer.Based on its structures,the emission mechanism is ascribed to cluster-triggered emission,elucidated from multianalyses(NMR,FTIR,UV absorbance and DLS).In presence of a dozen of competitive metal ions,PA24 emission at 450 nm is selectively quenched by Fe^(3+).PA24 is used as probe for Fe^(3+)and H_(2)O_(2) detections and in data encryption.Therefore,this work provides a novel face of polyamide with great potential applications as sensors in different fields.
基金supported by the Fundamental Research Funds for the Central Universities(No.2019QNA33)。
文摘This study carries out a simulated experiment of biogenic gas generation and studies the effects of gas generation on the pore structure and molecular structure of anthracite by mercury intrusion porosimetry,X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FT-IR).The results show that methanogenic bacteria can produce biogenic gas from anthracite.CO_(2) and CH4 are the main components of the generated biogas.After generation,some micropores(<10 nm)and transitional pores(10–100 nm)in the coal samples transform into large pores.In the high-pressure stage(pressure>100 MPa)of the mercury intrusion test,the specific surface area decreases by 19.79%compared with that of raw coal,and the pore volume increases by 7.25%in total.Microbial action on the molecular structure causes changes in the pore reconstruction.The FT-IR data show that the side chains and hydroxyl groups of the coal molecular structure in coal are easily metabolized by methanogenic bacteria and partially oxidized to form carboxylic acids.In addition,based on the XRD data,the aromatic lamellar structure in the coal is changed by microorganisms;it decreases in lateral size(La)and stacking thickness(Lc).This study enriches the theory of biogenic coalbed gas generation and provides a pathway for enhancing the permeability of high-rank coal reservoirs.
基金The National Key Research and Development Program of China(2017YFC0505606)the Top Discipline and First-class University Construction Project(ydzxxk201618)of Minzu University of China。
文摘Rural settlements serve as an important part of the rural landscape,and environmental conditions influence their spatial distribution.We hypothesize that there are variations in the spatial patterns of settlements across different farming–pastoral ecotones that exist in accordance with different human activities and environmental conditions.We used remote sensing imagery,digital elevation model,and GIS technology to analyze and compare the spatial patterns of settlements and factors influencing these patterns across pastoral,agricultural,and ecotone areas in Inner Mongolia,China.A Voronoi model,adjacency analysis,landscape metrics,and quantitative analysis were conducted.The results indicated that(1)the settlements in the three areas tended to have a random spatial distribution,and although there were no significant differences between the settlement types,agricultural settlements tended to be clustered and pastoral settlements tended to be evenly distributed;(2)the pastoral area had only a few large and sparsely fragmented patches;(3)the factors influencing settlement distribution mainly differed with respect to the NDVI,distance to roads and rivers,and elevation across three areas,but the slope degree was similar.These results indicated there are no significant differences between the spatial patterns of settlements along the agricultural to pastoral gradient,although environmental conditions differ.Consequently,we can optimize the spatial pattern of settlements and achieve sustainable development within farming–pastoral ecotones.
