Forty-five of 47 patients with distal ulcerative colitis completed a two-week double-blind, randomized, controlled trial to determine if 4-aminosalicylic acid (4-ASA) enemas, 1 g bid or 2 g bid, were therapeutically effective compared to placebo. Forty-one patients enrolled because they were refractory to or had side effects during conventional therapy with sulfasalazine or corticosteroids. Proctoscopic examination was done before and after two weeks of treatment. Patients kept daily diaries assessing: blood in stools, mucus in stools, tenesmus, abdominal pain, loss of appetite, fatigue, weight loss, and malaise. Severity of each symptom ranged from 0 (absent) to 3 (severe). A total severity score was calculated from the above for each patient. At the end of the two-week study, 35 patients elected to take 4-ASA in an open-label trial for one year. 4-ASA enemas in the 1-g bid but not the 2-g bid dosage were significantly more effective in improving symptoms than placebo: P less than or equal to 0.05. Neither dose of 4-ASA enema was better than placebo in improving the sigmoidoscopic appearance at the end of two-weeks. Forty-six percent of patients had complete resolution of all signs and symptoms in the open-label trial and 31% were better but still had sigmoidoscopic evidence of disease, a total response rate of 77%. Side effects were similar in the placebo and 4-ASA groups. We conclude that 4-ASA enemas in a dose of 1 g bid are safe and effective in the treatment of distal ulcerative colitis.

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Methanol is a fuel that can be produced using renewable electricity, green hydrogen, and a carbon-neutral carbon source. As a low-carbon liquid fuel, methanol is a leading candidate as a drop-in replacement fuel for rapid decarbonization of the transportation sector. In this work, methanol is tested experimentally in mixing-controlled compression ignition using a single-cylinder research engine. Specifically, the impact of a double injection strategy and high exhaust gas recirculation (EGR) dilution on performance and emissions parameters are studied. As a single-carbon, oxygenated fuel, methanol has a near-zero sooting potential, meaning there is no soot-NOx tradeoff as EGR dilution is increased. EGR dilution effectively reduces NOx emissions without a significant combustion efficiency or thermal efficiency penalty until the global equivalence ratio exceeds 0.9, at which point, a significant combustion efficiency penalty is incurred in the form of increased CO emissions. If stoichiometric operation with high EGR dilution is considered, engine-out NOx emissions are low, even at very high loads, and NOx aftertreatment is simplified through the use of a three-way catalyst. However, a relative decrease in the net fuel conversion efficiency of up to 8.5% was observed, demonstrating an emissions-efficiency tradeoff. Under lean and stoichiometric conditions, no appreciable agglomeration of particulate matter was observed.