Objective To compare the effectiveness of two kinds of defluorinating agents (bone char and modified clay) for removal of fluoride in drinking water,and to analyze their application feasibility in small towns.Methods Influencing factors on defluorinating efficiencies of the two kinds of defluorinating agents under the same conditions were studied,namely the effects of adsorption time,temperature,pH,common anions and cations,and solid-liquid ratio on defluorinating efficiencies were studied.The defluorinating efficiencies of the two kinds of defluorinating agents were validated by original groundwater in Jilin Province.The homemade bone char defluorinating agent and modified clay defluorinating agent were regenerated by NaOH and Al2(SO4)3,respectively,and their regeneration abilities were investigated.Results The adsorption data of the two kinds of defluorinating agents were fitted Langmuir model well,and the maximum adsorption capacities were 10.225 g/kg(bone char) and 0.587 g/kg(modified clay).The effect of temperature on defluorinating efficiencies was limited,with increasing temperature(10-35 ℃),the adsorption capacity of bone char and modified clay for fluoride ranged from 1.568 g/kg to 1.598 g/kg and 0.423 g/kg to 0.470 g/kg,respectively.Fluoride could be easily removed under low pH conditions,with increasing of pH(4-10),the adsorption capacity of bone char and modified clay for fluoride decreased from 1.598 g/kg to 1.523 g/kg and 0.724 g/kg to 0.320 g/kg,respectively.The defluorinating efficiencies were improved by common cations(Ca2+) in groundwater,and the adsorption capacity of bone char and modified clay for fluoride increased to 1.713 g/kg and 0.485 g/kg,respectively.Whereas,the defluorinating efficiencies were inhibited by common anions(HCO3-,SO42-) at a certain degree,and the adsorption capacities of bone char and modified clay for fluoride were decreased to 1.158 g/kg(HCO3-) and 0.237 g/kg(SO42),respectively.Defluoridation bone char could be regenerated by soaking in NaOH,and modified clay by immersion in Al2(SO4)3.The adsorption capacities of the two defluorinating agents that had been regenerated for three times still reached 94.6％ and 97.3％ of their original capacities.Conclusions Both of the homemade bone char defluorinating agent and modified clay defluorinating agent have good defluorinating efficiencies and can be regenerated for many times,which are perfectly suitable for application in small towns since they are simple and can be easily applied.The homemade bone char defluorinating agent is suitable for family drinking water and the homemade modified clay defluorinating agent would be more suitable for centralized drinking water.

Objective To evaluate the clinical efficacy and safety of sibutramine (Reductile )in Chinese obese patients. Methods Obese adults (BMI 27～45 kg/m 2) in six research centers received sibutamine 10 mg or placebo one tablet each day with a controlled-energy diet for 24 weeks by randomized, double-blinded, placebo-controlled study. Results For intent-to-treat analysis, 125 sibutramine-treated subjects and 126 placebo-treated subjects were evaluated. After 24 weeks, sibutramine-treated patients lost more weight (6.52?3.95)kg than placebo-treated patients (3.18?3.59)kg(P

A mixture of fructose and glucose was developed to simulate the hydrolysate of Jerusalem artichoke tubers, the fructose-based feedstock suitable for butanol production. With the initial pH of 5.5 without regulation during mixed-sugar fermentation, as high as 23.26 g/L sugars were remained unconverted, and butanol production of 5.51 g/L were obtained. Compared with either glucose or fructose fermentation, the early termination of mixed-sugar fermentation might be caused by toxic organic acids and the low pH. When the pH of the fermentation system was controlled at higher levels, it was found that sugars utilization was facilitated, but less butanol was produced due to the over-accumulation of organic acids. On the other hand, when the pH was controlled at lower levels, more sugars were remained unconverted, although butanol production was improved. Based on these experimental results, a stage-wise pH regulation strategy, e.g., controlling the pH of the fermentation system at 5.5 untill the OD620 reached 1.0, and then the pH control was removed, was developed, which significantly improved the fermentation performance of the system, with only 2.05 g/L sugars unconverted and 10.48 g/L butanol produced.
Acetone ; metabolism ; Butanols ; metabolism ; Fermentation ; Fructose ; metabolism ; Glucose ; metabolism ; Helianthus ; metabolism ; Hydrogen-Ion Concentration

Ethanol fermentation from Jerusalem artichoke tubers by recombinant Saccharomyces cerevisiae strains expressing the inulinase gene (inu) from Kluyveromyces marxianus was investigated. The inu native and pgk promoters were used to drive the expression of the inu gene, and the inulinase was expressed as an extracellular enzyme. All positive clones (confirmed by PCR) were able to express inulinase as measured by enzyme activity in the culture supernatant, among which two clones HI6/6 and HPI6/3 were selected, and their inulinase activity and ethanol fermentation performance were compared with their wild type. The inulinase activities of 86 and 23.8 U/mL were achieved, which were 4.6-fold and 1.5-fold higher than that of the wild type. Furthermore, ethanol fermentation was carried out with the recombinants and medium containing 200 g/L raw Jerusalem artichoke meal, and ethanol concentrations of 55 g/L and 52 g/L were obtained, with ethanol yields of 0.495 and 0.453, respectively, equivalent to 96.9% and 88.6% of the theoretical value.
Ethanol ; metabolism ; Fermentation ; Glycoside Hydrolases ; genetics ; secretion ; Helianthus ; metabolism ; Kluyveromyces ; genetics ; Metabolic Engineering ; methods ; Plant Tubers ; metabolism ; Recombination, Genetic ; Saccharomyces cerevisiae ; enzymology ; genetics

Butanol production from acid hydrolysate of Jerusalem artichoke juice by Clostridium acetobutylicum L7 was investigated, and it was found that natural components of the hydrolysate were suitable for solvent production with the species. With batch fermentation using the medium containing 48.36 g/L total sugars, 8.67 g/L butanol was produced at 60 h, and the ratio of butanol to acetone to ethanol was 0.58:0.36:0.06, which were similar to the fermentation with fructose as carbon source, but both of these two fermentations were slower than that with glucose as carbon source, indicating the fructose transport of the species might not be effective as that for glucose. When the total sugars of the medium were increased to 62.87 g/L, the residual sugars increased slightly from 3.09 g/L to 3.26 g/L, but butanol production of the fermentation system was improved significantly, with 11.21 g/L butanol produced and the ratio of butanol to acetone to ethanol at 0.64:0.29:0.05, which illustrated that an excess in sugars enhanced the butanol biosynthesis of the species by compromising its acetone production. When the sugar concentration of the medium was further increased, much more sugars were remained unconsumed, making the process economically unfavourable.
Butanols ; metabolism ; Clostridium acetobutylicum ; metabolism ; Fermentation ; Helianthus ; chemistry ; Industrial Microbiology ; methods