Modeling of biomass accumulation and filter bed st6ructure change in biofilters for gaseous toluene removal

[Abstract] In this study, a proper microbial growth model was established and analyzed to investigate the biomass accumulation process in biofilters. Four biofilters treating gaseous toluene were set up in parallel and were operated under different inlet toluene loadings for 100 days. Based on the experimental data of microbial biomass and toluene removal rate, the kinetic parameters were decided by either estimation from literature or parameter regression. The calculation results based on the model showed a good agreement with the experimental data of biomass change. By applying the model, it is found that lower than 50% of biomass in the filter bed was active during the last 50 days for the four biofilters. In addition, the void fraction of the filter bed with highest loading was only 55% of the initial level at the end of the operation. All the experimental and calculation results indicated that the microbial growth model could successfully describe the biomass accumulation process and have the potential to predict the long-term performance of biofilters

Effect of Zicao ointment on second-degree burns in rats

Purpose: To investigate the healing effect of Zicao Ointment (ZCO) on second-degree burns in rats.Methods: Male Sprague Dawley (SD) rats, weighing 200 – 220 g, were subjected to deep seconddegree skin burns by electrical scald instrument. The animals were divided into three groups as follows: (1) second-degree burns (control) group, (2) burns treated with 1 % silver sulfadiazine (SSD) group, and (3) second-degree burns treated with ZCO group. On days 3, 7 and 14 following administration of thedrug or ZCO, wound area and histopathological changes of rat epidermis were evaluated for the various groups.Results: On day 14, mean wound area of ZCO treatment group (0.28 ± 0.04 cm2) was significantly smaller than that of the control rats (2.63 ± 0.19 cm2, p < 0.01). Histological results indicate that inflammatory cells disappeared and were replaced by new granulation tissue by day 14 in the group treated with ZCO. Compared with SSD group rats, the inflammatory cells decreased and fibroblast and granulation tissues increased significantly in burnt rats treated with ZCO.Conclusion: Zicao Ointment is effective for the treatment of second-degree burns in rats and may be suitable for clinical therapy of second-degree burns.Keywords: Zicao ointment, Second-degree burns, Healing, Rat epidermis, Silver sulfadiazin