Bench-scale soil column experiments were carried out to evaluate the effectiveness of Cr（VI） bioremediation process in soils by using indigenous bacteria with the addition of bacteria nutrient media. Effects of part...Bench-scale soil column experiments were carried out to evaluate the effectiveness of Cr（VI） bioremediation process in soils by using indigenous bacteria with the addition of bacteria nutrient media. Effects of particle size, spray intensity, initial Cr（VI） concentration, circulation mode and soil depth on Cr（VI） remediation were studied. Results show that soils after 6 d remediation with spray intensity controlled in the range of 29.6-59.2 mL/min could well fulfill the requirement of concrete aggregate and roadbed material usage, for the leaching toxicity concentration of the Cr（VI） in treated soils under the chosen condition is far less than 5 mg/L The leaching toxicity and fractions of both hexavalent chromium and trivalent chromium from remediated soils were determined and compared with that of untreated soil. The results show that water soluble Cr（VI） declines from 1520.54 mg/kg to 0.68 mg/kg, exchangeable Cr（VI） decreases from 34.83 mg/kg to 0.01 mg/kg and carbonates-bonded Cr（V1） falls from 13.55 mg/kg to 0.68 mg/kg. Meanwhile, a corresponding increase in carbonate-bonded Cr（III）, Fe and Mn oxides-bonded Cr（III） and organic matter-bonded Cr（III） are found. It reveals that indigenous bacteria can leach out water soluble Cr（VI）, exchangeable Cr（VI） and carbonates-bonded Cr（VI） from contaminated soil followed by converting into carbonate-bonded Cr（III）, Fe and Mn oxides-bonded Cr（IlI）, organic matter-bonded Cr（III） and residual Cr（III）.展开更多
Poly(ε-caprolactone)(PCL)holds unique bioresorbability and competent biomechanical properties for tissueengineering application.However,PCL is hydrophobic intrinsically and poor in cell-biomaterial interaction.In thi...Poly(ε-caprolactone)(PCL)holds unique bioresorbability and competent biomechanical properties for tissueengineering application.However,PCL is hydrophobic intrinsically and poor in cell-biomaterial interaction.In this study,we prepared a composite based on PCL and bioactive tantalum(Ta)to understand the effects of direct laser micropatterning on composite surface properties.The PCL/Ta composite after preparation was surface-patterned by femtosecond laser and characterized with surface morphology,crystal structure,chemical composition,wettability and cellular response of fibroblast.It was found that laser micropatterning enlarged the difference of wetting properties(~15°)on PCL and PCL/Ta surfaces.The wetting changes was dependent on both material composition and lasermachined geometry.The blending of Ta enhanced surface wettability with prolonged contact time on the laser-machined line and rectangle microarrays.In vitro culture results showed beneficial effects of laser micropatterning on cell morphology of the fibroblasts.On the PCL/Ta surfaces with line and rectangle microarrays,the cells were more likely to bridge the sidewalls of the microgrooves,showing adaptive 3D morphologies to the micro/nano topographies on the sidewalls.These findings are envisaged to facilitate surface design and micropattern optimization for favorable tuning the cell response to biomedical PCL/Ta composites.展开更多
Culturable thermophilic microorganisms were enriched from samples collected from Lau Basin hydrothermal vents in artificial seawater medium at 45 ℃ and pH 7.0. Microbial diversities of the enriched communities were d...Culturable thermophilic microorganisms were enriched from samples collected from Lau Basin hydrothermal vents in artificial seawater medium at 45 ℃ and pH 7.0. Microbial diversities of the enriched communities were defined by performing a restriction fragment length polymorphism （RFLP） analysis of 16S rRNA gene sequences with enzymes MspI and Hin6 I. A total of 14 phylotypes have been detected by the RFLP patterns identified for 16S rRNA clone libraries of the enrichment. Analysis of sequences showed that at least four bacterial divisions presented in the clones libraries. The phyla Proteobacteria and Firmicutes were the most dominant groups. The majority of the sequences included in this analysis affiliated with Gamma Proteobacteria （71%） and Bacillus （23%）. Scanning electron micrographs revealed that there were abundant rod and coceoidal forms encased in sulphur and sodium chloride precipitate. These results revealed that there were a diversity of moderate thermophilic bacterial populations thrived in Lau Basin hydrothermal vents that were previously not detected by either molecular retrieval or strain purification techniques.展开更多
基金Project(50925417) supported by the National Funds for Distinguished Young Scientist, ChinaProject(50830301) supported by the Key Program of National Natural Science Foundation of ChinaProject(51074191) supported by the National Natural Science Foundation of China
文摘Bench-scale soil column experiments were carried out to evaluate the effectiveness of Cr（VI） bioremediation process in soils by using indigenous bacteria with the addition of bacteria nutrient media. Effects of particle size, spray intensity, initial Cr（VI） concentration, circulation mode and soil depth on Cr（VI） remediation were studied. Results show that soils after 6 d remediation with spray intensity controlled in the range of 29.6-59.2 mL/min could well fulfill the requirement of concrete aggregate and roadbed material usage, for the leaching toxicity concentration of the Cr（VI） in treated soils under the chosen condition is far less than 5 mg/L The leaching toxicity and fractions of both hexavalent chromium and trivalent chromium from remediated soils were determined and compared with that of untreated soil. The results show that water soluble Cr（VI） declines from 1520.54 mg/kg to 0.68 mg/kg, exchangeable Cr（VI） decreases from 34.83 mg/kg to 0.01 mg/kg and carbonates-bonded Cr（V1） falls from 13.55 mg/kg to 0.68 mg/kg. Meanwhile, a corresponding increase in carbonate-bonded Cr（III）, Fe and Mn oxides-bonded Cr（III） and organic matter-bonded Cr（III） are found. It reveals that indigenous bacteria can leach out water soluble Cr（VI）, exchangeable Cr（VI） and carbonates-bonded Cr（VI） from contaminated soil followed by converting into carbonate-bonded Cr（III）, Fe and Mn oxides-bonded Cr（IlI）, organic matter-bonded Cr（III） and residual Cr（III）.
基金Project(LY19A040001)supported by the Natural Science Foundation of Zhejiang Province,ChinaProjects(12147219,12035006)supported by the National Natural Science Foundation of China+1 种基金Project(531107050927)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(JY-Q/008/2016)supported by the Hunan University for the Yuelu Young Scholars,China。
文摘Poly(ε-caprolactone)(PCL)holds unique bioresorbability and competent biomechanical properties for tissueengineering application.However,PCL is hydrophobic intrinsically and poor in cell-biomaterial interaction.In this study,we prepared a composite based on PCL and bioactive tantalum(Ta)to understand the effects of direct laser micropatterning on composite surface properties.The PCL/Ta composite after preparation was surface-patterned by femtosecond laser and characterized with surface morphology,crystal structure,chemical composition,wettability and cellular response of fibroblast.It was found that laser micropatterning enlarged the difference of wetting properties(~15°)on PCL and PCL/Ta surfaces.The wetting changes was dependent on both material composition and lasermachined geometry.The blending of Ta enhanced surface wettability with prolonged contact time on the laser-machined line and rectangle microarrays.In vitro culture results showed beneficial effects of laser micropatterning on cell morphology of the fibroblasts.On the PCL/Ta surfaces with line and rectangle microarrays,the cells were more likely to bridge the sidewalls of the microgrooves,showing adaptive 3D morphologies to the micro/nano topographies on the sidewalls.These findings are envisaged to facilitate surface design and micropattern optimization for favorable tuning the cell response to biomedical PCL/Ta composites.
基金Project(200805032) supported by Grands from Scientific Research Program of Marine Public Welfare Industry of ChinaProject (DYXM-115-02-2-07) supported by China Ocean Mineral Resources R&D Association (COMRA)
文摘Culturable thermophilic microorganisms were enriched from samples collected from Lau Basin hydrothermal vents in artificial seawater medium at 45 ℃ and pH 7.0. Microbial diversities of the enriched communities were defined by performing a restriction fragment length polymorphism （RFLP） analysis of 16S rRNA gene sequences with enzymes MspI and Hin6 I. A total of 14 phylotypes have been detected by the RFLP patterns identified for 16S rRNA clone libraries of the enrichment. Analysis of sequences showed that at least four bacterial divisions presented in the clones libraries. The phyla Proteobacteria and Firmicutes were the most dominant groups. The majority of the sequences included in this analysis affiliated with Gamma Proteobacteria （71%） and Bacillus （23%）. Scanning electron micrographs revealed that there were abundant rod and coceoidal forms encased in sulphur and sodium chloride precipitate. These results revealed that there were a diversity of moderate thermophilic bacterial populations thrived in Lau Basin hydrothermal vents that were previously not detected by either molecular retrieval or strain purification techniques.
