Hydrodynamic behaviors in fermentative hydrogen bioreactors by pressure fluctuation analysis.

Three bioreactor configurations were employed in these investigations, which consisted of working volumes of 10, 1.2 and 1.2L. Power spectrum diagrams of bed pressure fluctuation were used with hydraulic retention times (HRT) and geometric factors to identify the flow regimes in the bioreactors, where HRT varied from 8 to 1h. It was found that the flow regimes in the bioreactors changed from a dispersed regime to coalesced and slugging regimes, when the biogas production rate (BPR) increased, as a result of decreasing the operating HRT. The flow regime was a dispersed bubble regime when the HRT was higher than 4h in the bioreactor, whereas when the HRT was 2h the coalesced bubble phenomena occurred in the bioreactor. A slugging regime was found when the HRT was lower than 1h in thinner bioreactor.

Randomized, double-blind, controlled trial of mifepristone in capsule versus tablet form followed by misoprostol for early medical abortion.

OBJECTIVE: To compare the efficacy and side-effects of mifepristone 75 mg in capsule form versus 150 mg in tablet form followed by misoprostol for medical termination of early pregnancy. STUDY DESIGN: In a prospective randomized, double-blind, placebo-controlled trial, a total of 480 women who were 49 days or less pregnant were randomized by means of a random number table to receive either two tablets in the morning and one tablet 12 h later for 2 days (group A) or three capsules orally twice daily for 2 days, the first dose being double all subsequent doses (group B). After a further 48 h, 600 microg misoprostol was given orally. Successful abortion was defined as complete abortion with no need for surgical aspiration. RESULTS: There were no significant differences between the two study groups in the rates of complete abortion (95.4% in group A versus 96.3% in group B), incomplete abortion (3.8% in group A, 3.3% in group B) and continued pregnancy (0.8% in group A, 0.4% in group B). No significant difference in the duration and amount of vaginal bleeding was observed. The incidence of side-effects, such as vomiting, nausea, headache, diarrhea and lower abdominal pain was similar in the two groups. CONCLUSIONS: Our results indicate that 75 mg mifepristone in capsule form combined with 600 microg misoprostol is as effective and safe as 150 mg mifepristone in tablet form for the termination of pregnancy up to 49 days.