Sn-Beta zeolites with borate salts catalyse the epimerization of carbohydrates via an intramolecular carbon shift

Carbohydrate epimerization is an essential technology for the widespread production of rare sugars. In contrast to other enzymes, most epimerases are only active on sugars substituted with phosphate or nucleotide groups, thus drastically restricting their use. Here we show that Sn-Beta zeolite in the presence of sodium tetraborate catalyses the selective epimerization of aldoses in aqueous media. Specifically, a 5 wt% aldose (for example, glucose, xylose or arabinose) solution with a 4:1 aldose:sodium tetraborate molar ratio reacted with catalytic amounts of Sn-Beta yields near-equilibrium epimerization product distributions. The reaction proceeds by way of a 1,2 carbon shift wherein the bond between C-2 and C-3 is cleaved and a new bond between C-1 and C-3 is formed, with C-1 moving to the C-2 position with an inverted configuration. This work provides a general method of performing carbohydrate epimerizations that surmounts the main disadvantages of current enzymatic and inorganic processes.National Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program) (Award DMR-0819762)DuPont MIT Alliance (Graduate Research Fellowship)National Institutes of Health (U.S.) (Grant EB-001960)National Institutes of Health (U.S.) (Grant EB-002026)National Science Foundation (U.S.). Graduate Research Fellowship Program (Grant 1122374

Fish oil supplementation during pregnancy and allergic respiratory disease in the adult offspring

Background Maternal supplementation with long-chain n-3 polyunsaturated fatty acids can have immunologic effects on the developing fetus through several anti-inflammatory pathways. However, there is limited knowledge of the long-term programming effects. Objective In a randomized controlled trial from 1990 with 24 years of follow-up, our aim was to determine whether supplementation with 2.7 g of long-chain n-3 polyunsaturated fatty acids in pregnancy can reduce the risk of asthma in offspring and allergic respiratory disease. Methods The randomized controlled trial included 533 women who were randomly assigned to receive fish oil during the third trimester of pregnancy, olive oil, or no oil in the ratio 2:1:1. The offspring were followed in a mandatory national prescription register, with complete follow-up for prescriptions related to the treatment of asthma and allergic rhinitis as primary outcomes. Furthermore, the offspring were invited to complete a questionnaire (74% participated) and attend a clinical examination (47% participated) at age 18 to 19 years. Results In intention-to-treat analyses the probability of having had asthma medication prescribed was significantly reduced in the fish oil group compared with the olive oil group (hazard ratio, 0.54, 95% CI, 0.32-0.90; P = .02). The probability of having had allergic rhinitis medication prescribed was also reduced in the fish oil group compared with the olive oil group (hazard ratio, 0.70, 95% CI, 0.47-1.05; P = .09), but the difference was not statistically significant. Self-reported information collected at age 18 to 19 years supported these findings. No associations were detected with respect to lung function outcomes or allergic sensitization at 18 to 19 years of age. Conclusion Maternal supplementation with fish oil might have prophylactic potential for long-term prevention of asthma in offspring