By increasing particle concentration and G value （root-mean-square velocity gradient） to enhance flocculation, a novel vertical-flow settler was designed to increase sedimentation effectiveness, and to simultaneousl...By increasing particle concentration and G value （root-mean-square velocity gradient） to enhance flocculation, a novel vertical-flow settler was designed to increase sedimentation effectiveness, and to simultaneously improve operational stabilization. Due to the gradual decrease in upward flow-rate of raw water, a floes blanket would form and suspend in the middle section of the settler, not at the bottom as in a conventional clarifier. Enough large floes, resulted from flocculation or fltration, would continuously settle out of the floes blanket, and simultaneously, the floes in raw water or those forming above the blanket would ceaselessly enter the floes blanket. As a result, the floes concentration in the blanket could keep a dynamic balance. The hydrodynamic shear in the blanket was improved by flow separation, which was induced by the abrupt change in flow channel. Due to the floes blanket and improved hydrodynamic shear, flocculation would be enhanced, which was helpful for removing fine particles in raw water. A comparative study showed that the novel vertical-flow settler had a much better performance in the removal of the particles in raw water than a conventional one, when they treated kaolin suspensions of different concentrations （500, 100 and 50 mg/L, respectively） coagulated by polyaluminum chloride（PAC1） at the up-flow rates of 1 and 2 mm/s, respectively.展开更多
In fission yeast (Schizosaccharomyces pombe), pac1 gene was cloned with 99.3% nucleo- tide sequence similarity with published pac1 in GenBank. In pET-5α expression system, the expres- sion product of cloned pac1 in E...In fission yeast (Schizosaccharomyces pombe), pac1 gene was cloned with 99.3% nucleo- tide sequence similarity with published pac1 in GenBank. In pET-5α expression system, the expres- sion product of cloned pac1 in E. coli showed activity to degrade the double-strand RNA. Harboring the binary vector pBI121, which contains pac1 gene, Agrobacterium tumefaciens strain LBA4404 was used to transform the wheat immature embryos pre- cultured 7―10 d. After preregeneration, regeneration and selection culture stage, totally 41 G418 resistant plants were obtained, in which 25 lines were proved to integrate with transgene and express transgene normally by PCR, Dot blot, RT-PCR and ELISA de- tection. Antivirus test carried out on 25 positive lines with high dose of Barley yellow dwarf virus-GPV re- vealed that 12 lines had resistance to BVDV-GPV in low level, another 12 lines had resistance to BVDV- GPV in middle level, and 1 line showed resistance to BVDV-GPV in high level. However, both low and middle level of resistance plants showed no symp- toms when infected by viruses at low dose, which suggested the dose-dependent effect of the resis- tance mediated by pac1 to BYDV-GPV.展开更多
基金The Hi-Tech Research and Development Program (863) of China (No. 2002AA601290 2003AA601010-03) and the NationalNatural Science Foundation of China (No. 50178067)
文摘By increasing particle concentration and G value （root-mean-square velocity gradient） to enhance flocculation, a novel vertical-flow settler was designed to increase sedimentation effectiveness, and to simultaneously improve operational stabilization. Due to the gradual decrease in upward flow-rate of raw water, a floes blanket would form and suspend in the middle section of the settler, not at the bottom as in a conventional clarifier. Enough large floes, resulted from flocculation or fltration, would continuously settle out of the floes blanket, and simultaneously, the floes in raw water or those forming above the blanket would ceaselessly enter the floes blanket. As a result, the floes concentration in the blanket could keep a dynamic balance. The hydrodynamic shear in the blanket was improved by flow separation, which was induced by the abrupt change in flow channel. Due to the floes blanket and improved hydrodynamic shear, flocculation would be enhanced, which was helpful for removing fine particles in raw water. A comparative study showed that the novel vertical-flow settler had a much better performance in the removal of the particles in raw water than a conventional one, when they treated kaolin suspensions of different concentrations （500, 100 and 50 mg/L, respectively） coagulated by polyaluminum chloride（PAC1） at the up-flow rates of 1 and 2 mm/s, respectively.
文摘In fission yeast (Schizosaccharomyces pombe), pac1 gene was cloned with 99.3% nucleo- tide sequence similarity with published pac1 in GenBank. In pET-5α expression system, the expres- sion product of cloned pac1 in E. coli showed activity to degrade the double-strand RNA. Harboring the binary vector pBI121, which contains pac1 gene, Agrobacterium tumefaciens strain LBA4404 was used to transform the wheat immature embryos pre- cultured 7―10 d. After preregeneration, regeneration and selection culture stage, totally 41 G418 resistant plants were obtained, in which 25 lines were proved to integrate with transgene and express transgene normally by PCR, Dot blot, RT-PCR and ELISA de- tection. Antivirus test carried out on 25 positive lines with high dose of Barley yellow dwarf virus-GPV re- vealed that 12 lines had resistance to BVDV-GPV in low level, another 12 lines had resistance to BVDV- GPV in middle level, and 1 line showed resistance to BVDV-GPV in high level. However, both low and middle level of resistance plants showed no symp- toms when infected by viruses at low dose, which suggested the dose-dependent effect of the resis- tance mediated by pac1 to BYDV-GPV.
