The maximum growth rate ofNitzschia elosterium at various concentrations of petroleum hydrocarbon was studied. The influence of petroleum hydrocarbon on cell size as a function of concentration was discussed. The rela...The maximum growth rate ofNitzschia elosterium at various concentrations of petroleum hydrocarbon was studied. The influence of petroleum hydrocarbon on cell size as a function of concentration was discussed. The relationship between maximum growth rate of Nitzschia closterium and cell median equivalent spherical diameter （MESD） was also carefully studied. The experi- mental results showed that the growth rate of Nitzschia elosterium was generally suppressed by petroleum hydrocarbon, which had greater effects at both low and high concentrations than at intermediate concentrations. No significant changes in cell size distribu- tion were observed during the growth period ofNitzsehia closterium. The Gaussian function could give a clear description of the cell size distribution ofNitzsehia closterium, and the MESD value ranged from 2.71 to 6.82 μm. The MESD decreased when the cell was exposed to petroleum hydrocarbon, and the reduction of cell MESD was much more significant at both relatively high and low hydrocarbon concentrations. The presence of petroleum hydrocarbon changed the relationship between μmax, and MESD from an allometric function to a U-shaped curve. When the MESD was below 5.07 μm,μmax decreased along with increased MESD, whereas when MESD was above 5.07 μm, μmax increased along with MESD, which deviated from the allometric model.展开更多
This paper reports a microfluidic method of continuous separation of marine algae and particles by DC dielectrophoresis. The locally non-uniform electric field is generated by an insulating PDMS triangle hurdle fabric...This paper reports a microfluidic method of continuous separation of marine algae and particles by DC dielectrophoresis. The locally non-uniform electric field is generated by an insulating PDMS triangle hurdle fabricated within a PDMS microchannel. Both the particles and algae are subject to negative DEP forces at the hurdle where the gradient of local electric-field strength is the strongest. The DEP force acting on the particle or the algae depends on particles' or algae's volume, shape and dielectric properties. Thus the moving particles and algae will be repelled to different streamlines when passing the hurdle. In this way, combined with the electroosmotic flow, continuous separation of algae of two different sizes, and continuous separation of polystyrene particles and algae with similar volume but different shape were achieved. This first demonstration of DC DEP separation of polystyrene particles and algae with similar sizes illustrates the great influence of dielectric properties on particle separation and potentials for sample pretreatment.展开更多
基金supported by the Chinese National Programs for High Technology Research and Development (No.2007AA09Z106).
文摘The maximum growth rate ofNitzschia elosterium at various concentrations of petroleum hydrocarbon was studied. The influence of petroleum hydrocarbon on cell size as a function of concentration was discussed. The relationship between maximum growth rate of Nitzschia closterium and cell median equivalent spherical diameter （MESD） was also carefully studied. The experi- mental results showed that the growth rate of Nitzschia elosterium was generally suppressed by petroleum hydrocarbon, which had greater effects at both low and high concentrations than at intermediate concentrations. No significant changes in cell size distribu- tion were observed during the growth period ofNitzsehia closterium. The Gaussian function could give a clear description of the cell size distribution ofNitzsehia closterium, and the MESD value ranged from 2.71 to 6.82 μm. The MESD decreased when the cell was exposed to petroleum hydrocarbon, and the reduction of cell MESD was much more significant at both relatively high and low hydrocarbon concentrations. The presence of petroleum hydrocarbon changed the relationship between μmax, and MESD from an allometric function to a U-shaped curve. When the MESD was below 5.07 μm,μmax decreased along with increased MESD, whereas when MESD was above 5.07 μm, μmax increased along with MESD, which deviated from the allometric model.
基金support from the Fundamental Research Funds for the Central Universities (2011QN105, 2011ZD014)the Dalian Science and Technology Foundation (2011J21DW005) to SONG YongXin+2 种基金National Science & Technology Pillar Program of China in 2010 (2010BAC68B02)Liaoning Science & Technology Program (2007405010) to SUN YeQingthe Natural Sciences and Engineering Research Council of Canada through a research grant to LI DongQing
文摘This paper reports a microfluidic method of continuous separation of marine algae and particles by DC dielectrophoresis. The locally non-uniform electric field is generated by an insulating PDMS triangle hurdle fabricated within a PDMS microchannel. Both the particles and algae are subject to negative DEP forces at the hurdle where the gradient of local electric-field strength is the strongest. The DEP force acting on the particle or the algae depends on particles' or algae's volume, shape and dielectric properties. Thus the moving particles and algae will be repelled to different streamlines when passing the hurdle. In this way, combined with the electroosmotic flow, continuous separation of algae of two different sizes, and continuous separation of polystyrene particles and algae with similar volume but different shape were achieved. This first demonstration of DC DEP separation of polystyrene particles and algae with similar sizes illustrates the great influence of dielectric properties on particle separation and potentials for sample pretreatment.
