The role of water on the equilibrium of esterification by immobilized lipase packed-bed column reactor
SummaryThe role of water on the continous synthesis of geranyl esters by immobilized lipase fromHumicola lanuginosa No. 3 was studied in a packed-bed column reactor (PBR) installed with a molecular sieve column for water extraction. The conversion degress by PBR were highly influenced by the water concentration throughout the reaction which acted as a determinant on the reaction equilibrium. Almost 100% conversion of geranyl laurate could be achieved under the optimum water-controlled conditions. The stability of the PBR system was for 35 days with the half-life of 38 days.
Continuous synthesis of esters by cell-bound fungal lipases in an organic solvent
SummaryStrains of Penicillium cyclopium and Rhizopus arrhizus secrete two extracellular lipases and contain an intracellular lipase. As these intracellular enzymes exhibited good synthetic activities in organic solvent, we designed a loop fixed-bed reactor for the continuous synthesis of esters. In a preliminary study we optimized the yield of ester synthesis using response surface methodology. With dodecanoic dodecyl ester as a model compound, the yields of ester synthesis were higher than 90%. It has been demonstrated that the reactor designed for this study is more efficient than a stirred batch reactor and more efficient than a fixed-bed reactor without a loop current or without a second catalytic column. In application, we have shown that lipases from R. arrhizus and P. cyclopium do not esterify tertiary alcohols like many lipases.
Access to antenatal care and children’s cognitive development: a comparative analysis in Ethiopia, Peru, Vietnam and India
ObjectivesEarly life interventions are considered essential for reducing the burden of health inequalities over the life course. This paper tests this issue empirically focusing on whether access to antenatal care can later reduce children’s health and educational inequalities.MethodsData came from the Young Lives Project for Ethiopia, Peru, Vietnam, and the State of Andhra Pradesh in India. We selected children born in early 2001/2002 and who were followed longitudinally in 2006/2007. We used multilevel mixed effects linear regression models to estimate the parameters of interest.ResultsWe found a positive and significant relationship between mothers’ access to antenatal care and their children’s cognitive development in all countries. In addition, we found a positive and significant relationship between antenatal care and children’s cognitive development for stunted children but only in Peru and Vietnam.ConclusionsWe conclude that (1) antenatal care has the potential to change the negative consequences of early nutritional deficiencies on later cognitive development in Peru and Vietnam; (2) differentials in the quality of antenatal care services could explain the cross-country differentials in the role of early life interventions found here.