An acclimatized mixed microbial culture,predominantly Pseudomonas sp.,was enriched from a sewage treatment plant,and its potential to simultaneously degrade mixtures of phenol and m-cresol was investigated during its ...An acclimatized mixed microbial culture,predominantly Pseudomonas sp.,was enriched from a sewage treatment plant,and its potential to simultaneously degrade mixtures of phenol and m-cresol was investigated during its growth in batch shake flasks.A 22 full factorial design with the two substrates at two different levels and different initial concentration ranges(low and high),was employed to carry out the biodegradation experiments.The substrates phenol and m-cresol were completely utilized within 21 h when ...展开更多
AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human...AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human hepatocytes was established by injection of primary human hepatocytes or Huh7 human hepatoma cells into the peritoneal cavities of fetal rats. Corresponding cells were subsequently transplanted into newborn rats via intrasplenic injection within 24h after birth. RESULTS: Mixed lymphocyte assays showed that spleen cells from non-tolerized rats were stimulated to proliferate when exposed to human hepatocytes, while cells from tolerized rats were not. Injections made between 15 d and 17 d of gestation produced optimal tolerization. Transplanted human hepatocytes in rat livers were visualized by immunohistochemical staining of human albumin. By dot blotting of genomic DNA in livers of tolerized rats 16 weeks after hepatocyte transplantation, it was found that approximately 2.5 X 10(5) human hepatocytes survived per rat liver. Human albumin mRNA was detected in rat livers by RT-PCR for 15 wk, and human albumin protein was also detectable in rat serum. CONCLUSION: Tolerization of an immuno-competent rat can permit transplantation, and survival of functional human hepatocytes.展开更多
A laboratory scale aerobic fixed film bioreactor packed with glass beads for biofilm growth was used to evaluate the removal efficiencies of COD and phenol for a carbohydrate—phenol mixture in wastewater. It was done...A laboratory scale aerobic fixed film bioreactor packed with glass beads for biofilm growth was used to evaluate the removal efficiencies of COD and phenol for a carbohydrate—phenol mixture in wastewater. It was done by an indigenous mixed culture inoculums developed after collecting sludge from a return line of an activated sludge plant. The test result on continuous flow in the above biofilm reactor indicated an optimum hydraulic loading range of 4-6.4 m3day-1m-2 for attainment of reasonable amount of COD removal in case of carbohydrate substrate only. The COD removal efficiency, however, gradually depleted from 100% to 54% by gradual increase in organic loading (OLR) from 0.72-4.32 kgday-1m-3, beyond which removal was not significant. For the identical loading conditions, in presence of phenol in the substrate along with carbohydrate, the COD removal was observed varying from 100-40% in the above organic loading range. The COD removal kinetics in presence of phenol also shows a decreasing trend compared to data obtained without the presence of phenol in wastewater that reveals biological inhibition. The experimental data were fitted in a simple plug flow model for evaluating the zero order, first order and Monod form of rate equations to evaluate the kinetics. It was found that Monod type rate equations combining a zero and first order rate expression is the best fit for the above hydraulic and organic loading that gives a best fit half velocity constant value of 35 mgL-1 (R2 = 0.9612).展开更多
文摘An acclimatized mixed microbial culture,predominantly Pseudomonas sp.,was enriched from a sewage treatment plant,and its potential to simultaneously degrade mixtures of phenol and m-cresol was investigated during its growth in batch shake flasks.A 22 full factorial design with the two substrates at two different levels and different initial concentration ranges(low and high),was employed to carry out the biodegradation experiments.The substrates phenol and m-cresol were completely utilized within 21 h when ...
文摘AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human hepatocytes was established by injection of primary human hepatocytes or Huh7 human hepatoma cells into the peritoneal cavities of fetal rats. Corresponding cells were subsequently transplanted into newborn rats via intrasplenic injection within 24h after birth. RESULTS: Mixed lymphocyte assays showed that spleen cells from non-tolerized rats were stimulated to proliferate when exposed to human hepatocytes, while cells from tolerized rats were not. Injections made between 15 d and 17 d of gestation produced optimal tolerization. Transplanted human hepatocytes in rat livers were visualized by immunohistochemical staining of human albumin. By dot blotting of genomic DNA in livers of tolerized rats 16 weeks after hepatocyte transplantation, it was found that approximately 2.5 X 10(5) human hepatocytes survived per rat liver. Human albumin mRNA was detected in rat livers by RT-PCR for 15 wk, and human albumin protein was also detectable in rat serum. CONCLUSION: Tolerization of an immuno-competent rat can permit transplantation, and survival of functional human hepatocytes.
文摘A laboratory scale aerobic fixed film bioreactor packed with glass beads for biofilm growth was used to evaluate the removal efficiencies of COD and phenol for a carbohydrate—phenol mixture in wastewater. It was done by an indigenous mixed culture inoculums developed after collecting sludge from a return line of an activated sludge plant. The test result on continuous flow in the above biofilm reactor indicated an optimum hydraulic loading range of 4-6.4 m3day-1m-2 for attainment of reasonable amount of COD removal in case of carbohydrate substrate only. The COD removal efficiency, however, gradually depleted from 100% to 54% by gradual increase in organic loading (OLR) from 0.72-4.32 kgday-1m-3, beyond which removal was not significant. For the identical loading conditions, in presence of phenol in the substrate along with carbohydrate, the COD removal was observed varying from 100-40% in the above organic loading range. The COD removal kinetics in presence of phenol also shows a decreasing trend compared to data obtained without the presence of phenol in wastewater that reveals biological inhibition. The experimental data were fitted in a simple plug flow model for evaluating the zero order, first order and Monod form of rate equations to evaluate the kinetics. It was found that Monod type rate equations combining a zero and first order rate expression is the best fit for the above hydraulic and organic loading that gives a best fit half velocity constant value of 35 mgL-1 (R2 = 0.9612).
