Single crystals of two 1,3-phenylenebis（oxy）diacetic acid（C10H10O8） compounds 1 and 2 were obtained via slow evaporation.The compounds were characterized by elemental analysis,IR and single-crystal X-ray diffracti...Single crystals of two 1,3-phenylenebis（oxy）diacetic acid（C10H10O8） compounds 1 and 2 were obtained via slow evaporation.The compounds were characterized by elemental analysis,IR and single-crystal X-ray diffraction.Compound 1（C10H14O8） crystallizes in the triclinic system,space group P1 with a = 6.3751（6）,b = 8.5311（8）,c = 11.4510（11）A,α = 93.3650（10）,β = 105.3190（10）,γ = 97.2140（10）°,V = 593.15（10） A^3,Z = 2,Mr = 262.21,Dc = 1.468 g/cm^3,F（000） = 276,GOOF = 1.005,° = 0.129 mm^-1,the final R = 0.0361 and w R = 0.0802 for 1854 observed reflections with I 〉 2σ（I）.Compound 2（C30H28N2O12） crystallizes in the triclinic system,space group P1 with a = 9.7416（13）,b = 11.839（2）,c = 12.9828（13） A,α = 74.191（4）,β = 77.953（2）,γ = 74.726（3）°,V = 1374.5（3） A^3,Z = 2,Mr = 608.54,Dc = 1.470 g/cm^3,F（000） = 636,GOOF = 1.061,° = 0.115 mm^-1,the final R = 0.0500 and w R = 0.1221 for 3966 observed reflections with I 〉 2σ（I）.Both compounds 1 and 2 exhibit 3D supramolecular structures under hydrogen bonding interactions.The results of preliminary antibacterial activity show that the title compounds display moderate antibacterial activities against the tested gram positive bacteria（S.aureus,C.albicans and B.subtilis） and gram negative bacteria（E.coli and P.aeruginosa）.展开更多
The 2,2'-((sulfonylbis(4,1-phenylene))bis(oxy))diacetic acid(H2L) and 4,4'-bipyridine(4,4'-bipy) are employed as organic ligands to react with metal salts to obtain two new metal-organic frameworks(MOFs), ...The 2,2'-((sulfonylbis(4,1-phenylene))bis(oxy))diacetic acid(H2L) and 4,4'-bipyridine(4,4'-bipy) are employed as organic ligands to react with metal salts to obtain two new metal-organic frameworks(MOFs), namely [M2L2(4,4'-bipy)](M = Zn(1), Cu(2)). They have been successfully synthesized under hydrothermal conditions. Single-crystal X-ray diffraction reveals that two complexes are isostructural and crystallize in orthorhombic system with space group Pbcn. All L^(2-) ligands bridge metal ions to form an infinite 1D Z-shaped chain along the a axis. Then through 4,4'-bipy, contiguous Z-shaped chains are linked to form a 2D layer structure. The luminescent studies of the H2L ligand and complex 1 in the solid state and thermogravimetric analyses(TGA) of two complexes are investigated.展开更多
A novel heteronuclear metal organic framework(MOF) incorporating both transition and alkali metal ions, namely, {(Ni_2K_2L_2·bipy]×6 H_2O]×2 H_2O}n(1, L = N-phosphonomethyl amino diacetic acid, bipy = 4...A novel heteronuclear metal organic framework(MOF) incorporating both transition and alkali metal ions, namely, {(Ni_2K_2L_2·bipy]×6 H_2O]×2 H_2O}n(1, L = N-phosphonomethyl amino diacetic acid, bipy = 4,4?-dipyridine) has been obtained. Its structure was established by single-crystal X-ray diffraction analysis and further characterized by elemental analysis and IR spectroscopy. The complex crystallizes in orthorhombic system, space group Pccn with a = 14.650(11), b = 36.56(3), c = 7.112(5) ? and V = 3809.3(8) ?~3. In this framework, bipy connects adjacent Ni–K heteronuclear coordination units into 1 D railway type chains, which are further propagated into 2 D deck-like array bearing large tunnels through the carboxylic oxygen from N-phosphonomethyl amino diacetic acid. The molar electrical conductivity of heteronuclear complex increases gradually with increasing the temperature. Complex 1 also exhibits strong photoluminescent emission in the visible region.展开更多
An important factor for the sustainability of soils highly susceptible to degradation is the use of monitoring tools that promptly and realistically reflect changes imposed on soil by different cropping systems. To se...An important factor for the sustainability of soils highly susceptible to degradation is the use of monitoring tools that promptly and realistically reflect changes imposed on soil by different cropping systems. To select soil quality indicator variables in sugarcane (Saccharum officinarum L.) production areas that fulfill the criteria of sensitivity to management practices and between-season consistency in the management discrimination, ten composite soil samples (0–10 cm) were collected in July 2005 (rainy season) and again in March 2006 (dry season) from areas under cultivation of organic sugarcane (OS), green sugarcane (GS), burned sugarcane (BS) and from an adjacent native forest (NF) area at Usina Triunfo, Boca da Mata, Alagoas, Brazil. Microbial biomass-C (MBC), total organic C (TOC), soil enzyme activity expressed as the rate of fluorescein diacetate (FDA) hydrolysis, mean weight diameter of water-stable soil aggregates (MWD), and percentage of water-stable macroaggregates (PWSA) were analyzed. Although MBC and TOC were higher in NF than in the cultivated areas, no differences were observed in these C pools between the three sugarcane systems. The response of FDA to the site management was dependent on the sampling time. In the rainy period, the activity followed the order: NF > OS > GS > BS, whereas in the dry season, only NF differed from the other treatments. Irrespective of the sampling time, MWD and PWSA decreased in the order NF > OS = GS > BS. The variables MWD and PWSA are quite sensitive for discriminating between site management histories regardless the sampling season.展开更多
In this article,an efficient,simple and environmentally friendly approach to the synthesis of diacetals(diketals)pentaerythritol using SOH-functionalized ionic liquids(ILs)as catalysts was reported.The ILs show high c...In this article,an efficient,simple and environmentally friendly approach to the synthesis of diacetals(diketals)pentaerythritol using SOH-functionalized ionic liquids(ILs)as catalysts was reported.The ILs show high catalytic activity and reusability with good to excellent yields of the desired products.Hammett method has been used to determine the acidity order of these ionic liquids and the results are consistent with the catalytic activities observed in acetalization reaction.Maximum product yield of 93%was observed on using[PSPy][OTf]as catalyst and it can be reused at least 8 times without obvious activity loss.展开更多
An ionic liquid material containing small size cation was synthesized and its composition and structure was determined by FT- IR, ^1H NMR, ^13C NMR and element analysis. However, its physical properties such as meltin...An ionic liquid material containing small size cation was synthesized and its composition and structure was determined by FT- IR, ^1H NMR, ^13C NMR and element analysis. However, its physical properties such as melting point, viscosity, conductivity, etc. were measured and the results show that the novel ionic liquid is composed of small cation with highly symmetry and larger anion which is very rare among the reported ionic liquid family.展开更多
Enzyme activities have the potential to indicate biological functioning of soils. In this study, soil urease, dehydrogenase, acid phosphatase and invertase activities and fluorescein diacetate(FDA) hydrolysis were mea...Enzyme activities have the potential to indicate biological functioning of soils. In this study, soil urease, dehydrogenase, acid phosphatase and invertase activities and fluorescein diacetate(FDA) hydrolysis were measured in two red soils spiked with Pb2+ranging from 0 to 2 400 mg kg-1to relate the enzyme activity values to both plant growth and the levels of available and total Pb2+concentrations in soils, and to examine the potential use of soil enzymes to assess the degrees of Pb contamination. Soil samples were taken for enzyme activities assaying during 3 month's incubation and then after planting of celery(Apium graveolens L.) and Chinese cabbage(Brassica chinensis L.). Enzyme activities in the red soil derived from arenaceous rock(RAR) were generally lower than those in the red soil developed on Quaternary red earths(REQ). At high Pb2+loadings, in both incubation and greenhouse studies, urease activity and FDA hydrolysis were significantly inhibited. But there were no significant relationships between soil dehydrogenase, acid phosphatase or invertase activity and soil Pb2+loadings in both RAR and REQ soils. The growth of celery and Chinese cabbage increased soil urease activity and FDA hydrolysis, but had minimal effect on dehydrogenase and invertase activities. There were positive correlations between celery biomass and soil urease activity and FDA hydrolysis. These results demonstrate that urease activity and FDA hydrolysis are more sensitive to Pb2+than acid phosphatase, dehydrogenase and invertase activities in the RAR and REQ soils.展开更多
Cropping activities may affect soil microbial activities and biomass,which would affect C and N cycling in soil and thus the crop yields and quality.In the present study,a combination of microcalorimetric,enzyme activ...Cropping activities may affect soil microbial activities and biomass,which would affect C and N cycling in soil and thus the crop yields and quality.In the present study,a combination of microcalorimetric,enzyme activity(sucrase,urease,catalase,and fluorescein diacetate hydrolysis),and real-time polymerase chain reaction(RT-PCR) analyses was used to investigate microbial status of farmland soils,collected from 5 different sites in Huazhong Agriculture University,China.Our results showed that among the 5sites,both positive and negative impacts of cropping activities on soil microbial activity were observed.Enzyme activity analysis showed that cropping activities reduced soil sucrase and urease activities,which would influence the C and N cycles in soil.Much more attentions should be given to microbial status affected by cropping activities in future.According to the correlation analysis,fluorescein diacetate hydrolysis showed a significantly(P < 0.05) negative correlation with the time to reach the maximum power output(R ——0.898),but a significantly(P < 0.05) positive correlation with bacterial gene copy number(R = 0.817).Soil catalase activity also showed a significantly(P < 0.05) positive correlation with bacterial gene copy number(R = 0.965).Using combined methods would provide virtual information of soil microbial status.展开更多
Ethylidene diacetate was prepared by reacting dimethyl ether,acetic acid and syngas in the presence of a catalytic system comprising RhI3,PPh3 and CH3I.The effects of reaction temperature,pressure,time and the CO/H2 m...Ethylidene diacetate was prepared by reacting dimethyl ether,acetic acid and syngas in the presence of a catalytic system comprising RhI3,PPh3 and CH3I.The effects of reaction temperature,pressure,time and the CO/H2 molar ratio on the conversion of dimethyl ether and the product selectivity were investigated under the same catalyst formulation.Results showed that a maximum conversion of dimethyl ether was obtained when a mixture consisting of 0.3 mol dimethyl ether and 120 ml acetic acid was reacted at 180 ℃ and 3.0 MPa for 10 h at a stirring speed of 600 rpm under a syngas flow with a CO/H2 molar ratio of 2.5,which was catalyzed by a catalyst mixture comprising 0.3 g RhI3,6 g PPh3 and 1.3 g CH3I.The selectivity of ethylidene diacetate increased with temperature,decreased with the CO/H2 molar ratio and exhibited a maximum with pressure.展开更多
We have reported that phenyliodonium diacetate[PhI（OAc）2] can serve as an eco-friendly mild oxidant for the epoxidation of alkenes in the presence of Mn（III） complex of meso-tetrakis（4-methoxyphenylporphyrin） ac...We have reported that phenyliodonium diacetate[PhI（OAc）2] can serve as an eco-friendly mild oxidant for the epoxidation of alkenes in the presence of Mn（III） complex of meso-tetrakis（4-methoxyphenylporphyrin） acetate Mn[（T4-OCH3P）P]OAc and imidazole in CH2Cl2.The amounts of the products（%） and selectivities are very dependent upon the electronic and steric properties of the starting alkenes.To evaluate the validity of this catalytic system for C ＂H activation,cyclohexane and ethylbenzene were oxidized under the epoxidation conditions.展开更多
In this work,novel antibacterial cellulose diacetate/poly(ethylenimine)/hyaluronic acid(CDA/PEI/HA)composite three-dimension(3D)scaffolds were prepared through electrospinning and post-processing.Firstly,CDA/PEI 2D co...In this work,novel antibacterial cellulose diacetate/poly(ethylenimine)/hyaluronic acid(CDA/PEI/HA)composite three-dimension(3D)scaffolds were prepared through electrospinning and post-processing.Firstly,CDA/PEI 2D composite nanofiber membranes were prepared by electrospinning,and then the CDA/PEI/HA 3D composite scaffolds were fabricated by post-processing and freeze-drying of CDA/PEI membranes.In particular,HA was added to improve the biocompatibility of composite scaffolds.Compared with CDA/PEI scaffolds,CDA/PEI/HA composite scaffolds showed higher water absorbing rate,higher water retention rate and higher mechanical strength.Moreover,CDA/PEI/HA composite scaffolds with abundant positive charge were benefit for improving antibacterial activity.CDA/PEI/HA scaffolds with biology function of HA were benefit for improving hemocompatibility and cell proliferation of CDA/PEI scaffolds.In summary,antibacterial CDA/PEI/HA scaffolds could protect wound from bacterial infection,improve cellular behavior and accelerate wound healing.Thus,CDA/PEI/HA scaffolds could be potential application for wound dressing.展开更多
We have investigated the properties of cellulose diacetate in solution by using laser light scattering. The cellulose diacetate molecules can form micelles and micellar clusters in acetone besides the individual chain...We have investigated the properties of cellulose diacetate in solution by using laser light scattering. The cellulose diacetate molecules can form micelles and micellar clusters in acetone besides the individual chains. As the concentration increases, the average hydrodynamic radius （Rh） linearly increases, whereas the ratio of gyration radius to hydrodynamic radins 〈Rg〉/〈Rh〉 linearly decreases. It indicates that the micelles associate and form micellar clusters due to the intermolecular interactions.展开更多
The title compound 3,9-bis（pyridin-2-yl）-2,4,8,10-tetraoxaspiro[5.5]undecane 4（C17H18N2O4） has been synthesized by the reaction of 2,2-bis（hydroxymethyl）propane-1,3-diol with pyridine-2-carbaldehyde in the prese...The title compound 3,9-bis（pyridin-2-yl）-2,4,8,10-tetraoxaspiro[5.5]undecane 4（C17H18N2O4） has been synthesized by the reaction of 2,2-bis（hydroxymethyl）propane-1,3-diol with pyridine-2-carbaldehyde in the presence of p-toluenesulfonic acid,and characterized by IR,1H-NMR and X-ray single-crystal diffraction.The crystal belongs to monoclinic system,space group C2/c with a = 25.133（2）,b = 5.7219（5）,c = 21.942（2）（A°） ,β = 99.145（2）°,V = 3115.3（5）（A°）^3,Z = 8,Dc = 1.340 g/cm^3,Mr = 314.33,F（000） = 1328,μ = 0.097 mm-1,MoKa radiation（λ = 0.71073）,R = 0.0352 and wR = 0.1022 for 2486 observed reflections with I 〉 2σ（I）.X-ray analysis reveals that the two 1,3-dioxane rings passing through the central spiro-C atom both adopt chair conformation.Intermolecular C-H…π,C-H…O and C-H…N weak interactions link the molecules to form a three-dimensional samdwich,which are effective in the stabilization of the crystal structure.展开更多
Cellulose diacetate(CDA)can be melt processed to produce numerous and widely-used plastic products.However,due to the high glass transition temperature(Tg)of CDA,the addition of up to 30 wt%of micromolecular plasticiz...Cellulose diacetate(CDA)can be melt processed to produce numerous and widely-used plastic products.However,due to the high glass transition temperature(Tg)of CDA,the addition of up to 30 wt%of micromolecular plasticizers is indispensable,which significantly reduces the dimensional stability and raises safety concerns from the migration of plasticizers.In this work,a series of CDA-graft poly(lactic acid)(CDA-g-PLA)copolymers were synthesized by ring-opening polymerization of lactide onto the hydroxyI groups of CDA.The resultant CDA-g-PLA copolymers possess adjustable degrees of substitution(DSpua)and side chain length(DPpLa)by controlling the reaction time and feed ratio.The Tgs and thermal flow temperatures(Ts)of CDA-g-PLA strongly depend on DPpA such as the Tgs decrease linearly with the increase of DPA.The CDA-g-PLA copolymers with the DPLA of 3-9 can be directly processed to transparent plastics by melt processing without any external plasticizers,because of their low Tfs of 170-215℃.More impressively.the CDA-g PLA can act as the macromolecular plasticizer.The obtained CDA/CDA-g-PLA has higher storage modulus,flexural modulus and Young's modulus than the commercial CDA plasticized with triethyl citrate.In addition,the CDA/CDA-g PLA exhibits high dimensional stabilty and anti-migration property.During a long term treatment at 80℃ and 60%humidity,the CDA/CDA-g-PLA can retain the initial shape.Therefore,this work not only proposes a facile method for achieving a direct thermoplastic processing of CDA,but also provides a macromolecular plasticizer for CDA to make lightweight,stable and safer biobased thermoplastics.展开更多
Some medicinal plants are used traditionally in Saudi Arabia to treat many bacterial infections. Three plants, lemongrass (Oymbopogon citrates), lantana (Lantana cama-ra), and wild olive leaves (Olea europaea) were co...Some medicinal plants are used traditionally in Saudi Arabia to treat many bacterial infections. Three plants, lemongrass (Oymbopogon citrates), lantana (Lantana cama-ra), and wild olive leaves (Olea europaea) were collected, identified, extracted with either hot water or organic solvents (methanol, diethyl ether, ethyl acetate and n-butanol) to investigate their antibacterial activities against E. coli. The methanol ex-tracts of lemongrass, lantana and olive showed the highest activities against Esherichia coil while aqueous extract exhibited the lowest activities. Thus, the antibacterial activities of the methanolic extract of the three tested plants were determined using agar well diffusion method against some bacterial pathogens, isolated from urine samples. The highest antibacterial activity was recorded for themethanolic extract of lemongrass against all tested bacteria, E. coli, K. pneumoniae, P. aeuroginosa, P. mirabilis, E. faecalis and S. aureus. The tested bacteria differed with regard to their susceptibility to plant extracts. Lemongrass was the most active extract followed by lantana and wild olive extracts. Minimal inhibitory concentrations (MICs) of the methanolic extract of Lemongrass and some used antibiotics, Erythromycin, Tetracycline, Amoxicillin, Ciprofloxacin and Chloramphenicol were determined usingfluorescein diacetate method. Synergistic effect of the methanolic extract of lemongrass with the previous antibiotics against the tested clinical bacterial isolates was determined and the Fractional inhibitory concentrations (FIC) of different combination of the extract and the antibiotics were determined. FIC index (FICI) was calculated and it was ranged from 0.08 - 0.98. The interaction between the tested plant extract and the tested antibiotics was either synergistic or additive effects and no antagonistic effect was recorded. In conclusion, methanolic extract of lemongrass singly or in combination with some antibiotics can be used to treat pathogenic bacteria that cause urinary tract infections.展开更多
A simple and highly efficient one-pot method for the construction of α-hydroxyketone phosphates from terminal alkynes and H-phosphine oxides has been developed in the presence of PhI（OAc）2 and H20. The present prot...A simple and highly efficient one-pot method for the construction of α-hydroxyketone phosphates from terminal alkynes and H-phosphine oxides has been developed in the presence of PhI（OAc）2 and H20. The present protocol provides an attractive approach to α-hydroxyketone phosphates in good to high yields, with the advantages of operation simplicity, the use of commercially available materials, broad substrate scope, high atom efficiency and good tolerance to scale-up synthesis.展开更多
A mild and efficient method for diacetylation reaction was developed,by which diacetate could be achieved through the reaction of aldehyde with acetic anhydride,in the presence of cobalt sulfate,with an admirable yiel...A mild and efficient method for diacetylation reaction was developed,by which diacetate could be achieved through the reaction of aldehyde with acetic anhydride,in the presence of cobalt sulfate,with an admirable yield,at room temperature,without solvent.The catalyst could be recycled six times without a distinct loss of activity.展开更多
A series of novel hybrid photoinitiators(YPhCOPhXPhI^+PhPF_6^-,Y = 4-NO_2,4-MeO or 3-Cl,X = O,OCH_2,or nothing),which contain multiple aromatic rings(PhCOPhXPh),were prepared by reaction of easily available aryl keton...A series of novel hybrid photoinitiators(YPhCOPhXPhI^+PhPF_6^-,Y = 4-NO_2,4-MeO or 3-Cl,X = O,OCH_2,or nothing),which contain multiple aromatic rings(PhCOPhXPh),were prepared by reaction of easily available aryl ketones (YPhCOPhXPh) with iodosobenzene diacetate[PhI^+OCOCH_3(CH_3CO_2)^-].The inset of an aromatic ring into p-benzoyldiphenyliodonium hexafluorophophate(PhCOPhI^+PhPF_6^-)(BDPIH,He-type photoinitiator) between diphenyliodonium and benzoyl is propitious both to the preparation and the photoinitiat...展开更多
基金Supported by the National Natural Science Foundation of China(No.21264011,20961007)the Aviation Fund(No.2014ZF56020)
文摘Single crystals of two 1,3-phenylenebis（oxy）diacetic acid（C10H10O8） compounds 1 and 2 were obtained via slow evaporation.The compounds were characterized by elemental analysis,IR and single-crystal X-ray diffraction.Compound 1（C10H14O8） crystallizes in the triclinic system,space group P1 with a = 6.3751（6）,b = 8.5311（8）,c = 11.4510（11）A,α = 93.3650（10）,β = 105.3190（10）,γ = 97.2140（10）°,V = 593.15（10） A^3,Z = 2,Mr = 262.21,Dc = 1.468 g/cm^3,F（000） = 276,GOOF = 1.005,° = 0.129 mm^-1,the final R = 0.0361 and w R = 0.0802 for 1854 observed reflections with I 〉 2σ（I）.Compound 2（C30H28N2O12） crystallizes in the triclinic system,space group P1 with a = 9.7416（13）,b = 11.839（2）,c = 12.9828（13） A,α = 74.191（4）,β = 77.953（2）,γ = 74.726（3）°,V = 1374.5（3） A^3,Z = 2,Mr = 608.54,Dc = 1.470 g/cm^3,F（000） = 636,GOOF = 1.061,° = 0.115 mm^-1,the final R = 0.0500 and w R = 0.1221 for 3966 observed reflections with I 〉 2σ（I）.Both compounds 1 and 2 exhibit 3D supramolecular structures under hydrogen bonding interactions.The results of preliminary antibacterial activity show that the title compounds display moderate antibacterial activities against the tested gram positive bacteria（S.aureus,C.albicans and B.subtilis） and gram negative bacteria（E.coli and P.aeruginosa）.
基金supported by the Natural Science Foundation of Zhejiang Province(No.Y12B010003)。
文摘The 2,2'-((sulfonylbis(4,1-phenylene))bis(oxy))diacetic acid(H2L) and 4,4'-bipyridine(4,4'-bipy) are employed as organic ligands to react with metal salts to obtain two new metal-organic frameworks(MOFs), namely [M2L2(4,4'-bipy)](M = Zn(1), Cu(2)). They have been successfully synthesized under hydrothermal conditions. Single-crystal X-ray diffraction reveals that two complexes are isostructural and crystallize in orthorhombic system with space group Pbcn. All L^(2-) ligands bridge metal ions to form an infinite 1D Z-shaped chain along the a axis. Then through 4,4'-bipy, contiguous Z-shaped chains are linked to form a 2D layer structure. The luminescent studies of the H2L ligand and complex 1 in the solid state and thermogravimetric analyses(TGA) of two complexes are investigated.
基金This project was supported by the National Foundation for Science of China(No.U180411457)Foundation for Science&Technology Innovation Talents in Henan province(No.16410010012)the Foundation of Education Committee of Henan province(No.182102310897)
文摘A novel heteronuclear metal organic framework(MOF) incorporating both transition and alkali metal ions, namely, {(Ni_2K_2L_2·bipy]×6 H_2O]×2 H_2O}n(1, L = N-phosphonomethyl amino diacetic acid, bipy = 4,4?-dipyridine) has been obtained. Its structure was established by single-crystal X-ray diffraction analysis and further characterized by elemental analysis and IR spectroscopy. The complex crystallizes in orthorhombic system, space group Pccn with a = 14.650(11), b = 36.56(3), c = 7.112(5) ? and V = 3809.3(8) ?~3. In this framework, bipy connects adjacent Ni–K heteronuclear coordination units into 1 D railway type chains, which are further propagated into 2 D deck-like array bearing large tunnels through the carboxylic oxygen from N-phosphonomethyl amino diacetic acid. The molar electrical conductivity of heteronuclear complex increases gradually with increasing the temperature. Complex 1 also exhibits strong photoluminescent emission in the visible region.
基金Project supported by the Brazilian Corporation for Agricultural Research (No.02.03.01.01.04) the Usina Triunfo(Alagoas State), Brazil.
文摘An important factor for the sustainability of soils highly susceptible to degradation is the use of monitoring tools that promptly and realistically reflect changes imposed on soil by different cropping systems. To select soil quality indicator variables in sugarcane (Saccharum officinarum L.) production areas that fulfill the criteria of sensitivity to management practices and between-season consistency in the management discrimination, ten composite soil samples (0–10 cm) were collected in July 2005 (rainy season) and again in March 2006 (dry season) from areas under cultivation of organic sugarcane (OS), green sugarcane (GS), burned sugarcane (BS) and from an adjacent native forest (NF) area at Usina Triunfo, Boca da Mata, Alagoas, Brazil. Microbial biomass-C (MBC), total organic C (TOC), soil enzyme activity expressed as the rate of fluorescein diacetate (FDA) hydrolysis, mean weight diameter of water-stable soil aggregates (MWD), and percentage of water-stable macroaggregates (PWSA) were analyzed. Although MBC and TOC were higher in NF than in the cultivated areas, no differences were observed in these C pools between the three sugarcane systems. The response of FDA to the site management was dependent on the sampling time. In the rainy period, the activity followed the order: NF > OS > GS > BS, whereas in the dry season, only NF differed from the other treatments. Irrespective of the sampling time, MWD and PWSA decreased in the order NF > OS = GS > BS. The variables MWD and PWSA are quite sensitive for discriminating between site management histories regardless the sampling season.
基金supported by National 863 High-Tech Research and Development Program of China(No. 2007AA05Z101)
文摘In this article,an efficient,simple and environmentally friendly approach to the synthesis of diacetals(diketals)pentaerythritol using SOH-functionalized ionic liquids(ILs)as catalysts was reported.The ILs show high catalytic activity and reusability with good to excellent yields of the desired products.Hammett method has been used to determine the acidity order of these ionic liquids and the results are consistent with the catalytic activities observed in acetalization reaction.Maximum product yield of 93%was observed on using[PSPy][OTf]as catalyst and it can be reused at least 8 times without obvious activity loss.
基金support by the Natural Science Foundation of China(Nos.20273021 and20173017)Province and Educational Department of Heilongjiang,China(Nos.11521068 and TB2005-16).
文摘An ionic liquid material containing small size cation was synthesized and its composition and structure was determined by FT- IR, ^1H NMR, ^13C NMR and element analysis. However, its physical properties such as melting point, viscosity, conductivity, etc. were measured and the results show that the novel ionic liquid is composed of small cation with highly symmetry and larger anion which is very rare among the reported ionic liquid family.
基金Supported by the China-EU Science&Technology Cooperation Program(No.2011DFA101222)
文摘Enzyme activities have the potential to indicate biological functioning of soils. In this study, soil urease, dehydrogenase, acid phosphatase and invertase activities and fluorescein diacetate(FDA) hydrolysis were measured in two red soils spiked with Pb2+ranging from 0 to 2 400 mg kg-1to relate the enzyme activity values to both plant growth and the levels of available and total Pb2+concentrations in soils, and to examine the potential use of soil enzymes to assess the degrees of Pb contamination. Soil samples were taken for enzyme activities assaying during 3 month's incubation and then after planting of celery(Apium graveolens L.) and Chinese cabbage(Brassica chinensis L.). Enzyme activities in the red soil derived from arenaceous rock(RAR) were generally lower than those in the red soil developed on Quaternary red earths(REQ). At high Pb2+loadings, in both incubation and greenhouse studies, urease activity and FDA hydrolysis were significantly inhibited. But there were no significant relationships between soil dehydrogenase, acid phosphatase or invertase activity and soil Pb2+loadings in both RAR and REQ soils. The growth of celery and Chinese cabbage increased soil urease activity and FDA hydrolysis, but had minimal effect on dehydrogenase and invertase activities. There were positive correlations between celery biomass and soil urease activity and FDA hydrolysis. These results demonstrate that urease activity and FDA hydrolysis are more sensitive to Pb2+than acid phosphatase, dehydrogenase and invertase activities in the RAR and REQ soils.
基金supported by the Public Welfare Project of Ministry of Environmental Protection of China(Nos.201409042 and 201509049)the National Natural Science Foundation of China(Nos. 41430106,41273092,U1402234,and 41603083)
文摘Cropping activities may affect soil microbial activities and biomass,which would affect C and N cycling in soil and thus the crop yields and quality.In the present study,a combination of microcalorimetric,enzyme activity(sucrase,urease,catalase,and fluorescein diacetate hydrolysis),and real-time polymerase chain reaction(RT-PCR) analyses was used to investigate microbial status of farmland soils,collected from 5 different sites in Huazhong Agriculture University,China.Our results showed that among the 5sites,both positive and negative impacts of cropping activities on soil microbial activity were observed.Enzyme activity analysis showed that cropping activities reduced soil sucrase and urease activities,which would influence the C and N cycles in soil.Much more attentions should be given to microbial status affected by cropping activities in future.According to the correlation analysis,fluorescein diacetate hydrolysis showed a significantly(P < 0.05) negative correlation with the time to reach the maximum power output(R ——0.898),but a significantly(P < 0.05) positive correlation with bacterial gene copy number(R = 0.817).Soil catalase activity also showed a significantly(P < 0.05) positive correlation with bacterial gene copy number(R = 0.965).Using combined methods would provide virtual information of soil microbial status.
文摘Ethylidene diacetate was prepared by reacting dimethyl ether,acetic acid and syngas in the presence of a catalytic system comprising RhI3,PPh3 and CH3I.The effects of reaction temperature,pressure,time and the CO/H2 molar ratio on the conversion of dimethyl ether and the product selectivity were investigated under the same catalyst formulation.Results showed that a maximum conversion of dimethyl ether was obtained when a mixture consisting of 0.3 mol dimethyl ether and 120 ml acetic acid was reacted at 180 ℃ and 3.0 MPa for 10 h at a stirring speed of 600 rpm under a syngas flow with a CO/H2 molar ratio of 2.5,which was catalyzed by a catalyst mixture comprising 0.3 g RhI3,6 g PPh3 and 1.3 g CH3I.The selectivity of ethylidene diacetate increased with temperature,decreased with the CO/H2 molar ratio and exhibited a maximum with pressure.
基金Supported by the Yasouj University Research Council and Department of Chemistry of Yasouj University,Iran
文摘We have reported that phenyliodonium diacetate[PhI（OAc）2] can serve as an eco-friendly mild oxidant for the epoxidation of alkenes in the presence of Mn（III） complex of meso-tetrakis（4-methoxyphenylporphyrin） acetate Mn[（T4-OCH3P）P]OAc and imidazole in CH2Cl2.The amounts of the products（%） and selectivities are very dependent upon the electronic and steric properties of the starting alkenes.To evaluate the validity of this catalytic system for C ＂H activation,cyclohexane and ethylbenzene were oxidized under the epoxidation conditions.
基金financially supported by the National Key Research and Development Program(No.2016YFC1100703)。
文摘In this work,novel antibacterial cellulose diacetate/poly(ethylenimine)/hyaluronic acid(CDA/PEI/HA)composite three-dimension(3D)scaffolds were prepared through electrospinning and post-processing.Firstly,CDA/PEI 2D composite nanofiber membranes were prepared by electrospinning,and then the CDA/PEI/HA 3D composite scaffolds were fabricated by post-processing and freeze-drying of CDA/PEI membranes.In particular,HA was added to improve the biocompatibility of composite scaffolds.Compared with CDA/PEI scaffolds,CDA/PEI/HA composite scaffolds showed higher water absorbing rate,higher water retention rate and higher mechanical strength.Moreover,CDA/PEI/HA composite scaffolds with abundant positive charge were benefit for improving antibacterial activity.CDA/PEI/HA scaffolds with biology function of HA were benefit for improving hemocompatibility and cell proliferation of CDA/PEI scaffolds.In summary,antibacterial CDA/PEI/HA scaffolds could protect wound from bacterial infection,improve cellular behavior and accelerate wound healing.Thus,CDA/PEI/HA scaffolds could be potential application for wound dressing.
基金ACKNOWLEDGMENTS This work was supported by China Tobacco Guangdong Industrial Co., Ltd., National Natural Science Foundation of China （No21234003 and No.51303059）, and the Fundamental Research Funds for Central Universities.
文摘We have investigated the properties of cellulose diacetate in solution by using laser light scattering. The cellulose diacetate molecules can form micelles and micellar clusters in acetone besides the individual chains. As the concentration increases, the average hydrodynamic radius （Rh） linearly increases, whereas the ratio of gyration radius to hydrodynamic radins 〈Rg〉/〈Rh〉 linearly decreases. It indicates that the micelles associate and form micellar clusters due to the intermolecular interactions.
基金supported by the National Natural Science Foundation of China (No. 20872051 and 21002009)the Scientific and Technological Project of Changzhou (CJ20115019)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The title compound 3,9-bis（pyridin-2-yl）-2,4,8,10-tetraoxaspiro[5.5]undecane 4（C17H18N2O4） has been synthesized by the reaction of 2,2-bis（hydroxymethyl）propane-1,3-diol with pyridine-2-carbaldehyde in the presence of p-toluenesulfonic acid,and characterized by IR,1H-NMR and X-ray single-crystal diffraction.The crystal belongs to monoclinic system,space group C2/c with a = 25.133（2）,b = 5.7219（5）,c = 21.942（2）（A°） ,β = 99.145（2）°,V = 3115.3（5）（A°）^3,Z = 8,Dc = 1.340 g/cm^3,Mr = 314.33,F（000） = 1328,μ = 0.097 mm-1,MoKa radiation（λ = 0.71073）,R = 0.0352 and wR = 0.1022 for 2486 observed reflections with I 〉 2σ（I）.X-ray analysis reveals that the two 1,3-dioxane rings passing through the central spiro-C atom both adopt chair conformation.Intermolecular C-H…π,C-H…O and C-H…N weak interactions link the molecules to form a three-dimensional samdwich,which are effective in the stabilization of the crystal structure.
基金This work was finacially supported by the National Key Research and Development Program of China(No.2017YFA0403103)the Key Programs of the Chinese Academy of Sciences(No.ZDRW-CN-2018-2)the Youth Innovation Promotion Association CAS(No.2018040).
文摘Cellulose diacetate(CDA)can be melt processed to produce numerous and widely-used plastic products.However,due to the high glass transition temperature(Tg)of CDA,the addition of up to 30 wt%of micromolecular plasticizers is indispensable,which significantly reduces the dimensional stability and raises safety concerns from the migration of plasticizers.In this work,a series of CDA-graft poly(lactic acid)(CDA-g-PLA)copolymers were synthesized by ring-opening polymerization of lactide onto the hydroxyI groups of CDA.The resultant CDA-g-PLA copolymers possess adjustable degrees of substitution(DSpua)and side chain length(DPpLa)by controlling the reaction time and feed ratio.The Tgs and thermal flow temperatures(Ts)of CDA-g-PLA strongly depend on DPpA such as the Tgs decrease linearly with the increase of DPA.The CDA-g-PLA copolymers with the DPLA of 3-9 can be directly processed to transparent plastics by melt processing without any external plasticizers,because of their low Tfs of 170-215℃.More impressively.the CDA-g PLA can act as the macromolecular plasticizer.The obtained CDA/CDA-g-PLA has higher storage modulus,flexural modulus and Young's modulus than the commercial CDA plasticized with triethyl citrate.In addition,the CDA/CDA-g PLA exhibits high dimensional stabilty and anti-migration property.During a long term treatment at 80℃ and 60%humidity,the CDA/CDA-g-PLA can retain the initial shape.Therefore,this work not only proposes a facile method for achieving a direct thermoplastic processing of CDA,but also provides a macromolecular plasticizer for CDA to make lightweight,stable and safer biobased thermoplastics.
文摘Some medicinal plants are used traditionally in Saudi Arabia to treat many bacterial infections. Three plants, lemongrass (Oymbopogon citrates), lantana (Lantana cama-ra), and wild olive leaves (Olea europaea) were collected, identified, extracted with either hot water or organic solvents (methanol, diethyl ether, ethyl acetate and n-butanol) to investigate their antibacterial activities against E. coli. The methanol ex-tracts of lemongrass, lantana and olive showed the highest activities against Esherichia coil while aqueous extract exhibited the lowest activities. Thus, the antibacterial activities of the methanolic extract of the three tested plants were determined using agar well diffusion method against some bacterial pathogens, isolated from urine samples. The highest antibacterial activity was recorded for themethanolic extract of lemongrass against all tested bacteria, E. coli, K. pneumoniae, P. aeuroginosa, P. mirabilis, E. faecalis and S. aureus. The tested bacteria differed with regard to their susceptibility to plant extracts. Lemongrass was the most active extract followed by lantana and wild olive extracts. Minimal inhibitory concentrations (MICs) of the methanolic extract of Lemongrass and some used antibiotics, Erythromycin, Tetracycline, Amoxicillin, Ciprofloxacin and Chloramphenicol were determined usingfluorescein diacetate method. Synergistic effect of the methanolic extract of lemongrass with the previous antibiotics against the tested clinical bacterial isolates was determined and the Fractional inhibitory concentrations (FIC) of different combination of the extract and the antibiotics were determined. FIC index (FICI) was calculated and it was ranged from 0.08 - 0.98. The interaction between the tested plant extract and the tested antibiotics was either synergistic or additive effects and no antagonistic effect was recorded. In conclusion, methanolic extract of lemongrass singly or in combination with some antibiotics can be used to treat pathogenic bacteria that cause urinary tract infections.
基金financial support from the National Natural Science Foundation of China(Nos.21172213,21302109,21402184,and 21572217)
文摘A simple and highly efficient one-pot method for the construction of α-hydroxyketone phosphates from terminal alkynes and H-phosphine oxides has been developed in the presence of PhI（OAc）2 and H20. The present protocol provides an attractive approach to α-hydroxyketone phosphates in good to high yields, with the advantages of operation simplicity, the use of commercially available materials, broad substrate scope, high atom efficiency and good tolerance to scale-up synthesis.
文摘A mild and efficient method for diacetylation reaction was developed,by which diacetate could be achieved through the reaction of aldehyde with acetic anhydride,in the presence of cobalt sulfate,with an admirable yield,at room temperature,without solvent.The catalyst could be recycled six times without a distinct loss of activity.
基金supported by the National Natural Science Foundation of China(No.20772102)Doctor Student Research Foundation of Chinese Education Ministry(No.20060530002)
文摘A series of novel hybrid photoinitiators(YPhCOPhXPhI^+PhPF_6^-,Y = 4-NO_2,4-MeO or 3-Cl,X = O,OCH_2,or nothing),which contain multiple aromatic rings(PhCOPhXPh),were prepared by reaction of easily available aryl ketones (YPhCOPhXPh) with iodosobenzene diacetate[PhI^+OCOCH_3(CH_3CO_2)^-].The inset of an aromatic ring into p-benzoyldiphenyliodonium hexafluorophophate(PhCOPhI^+PhPF_6^-)(BDPIH,He-type photoinitiator) between diphenyliodonium and benzoyl is propitious both to the preparation and the photoinitiat...
