25 research outputs found

    Electrospray as a Tool for Drug Micro- and Nanoparticle Patterning

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    Carbamazepine (CBZ) microparticles of different sizes and shapes, including spheres, q-tips, elongated spheres, and tear-shaped particles, were formed by electrospraying solutions of different CBZ concentrations. The particle characteristics were determined by the interplay between jet formation, droplet breakup, solvent evaporation, and eventual particle solidification. The average particle size increased with increasing CBZ concentration, with particles of different shapes being observed for different CBZ concentrations. The cascade of sizes and shapes observed was interpreted in terms of Rayleigh instability theory as applied to charged jets and droplets, with the final sizes depending upon the time needed to evaporate the solvent sufficiently for CBZ to solidify; the lower the initial concentration of CBZ, the smaller the final droplets/particles that are formed

    Engineering E. coli for the biosynthesis of 3-hydroxy-γ-butyrolactone (3HBL) and 3,4-dihydroxybutyric acid (3,4-DHBA) as value-added chemicals from glucose as a sole carbon source

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    3-hydroxy-γ-butyrolactone (3HBL) is a versatile chiral synthon, deemed a top value-added chemical from biomass by the DOE. We recently reported the first biosynthetic pathway towards 3HBL and its hydrolyzed form, 3,4-dihydroxybutyric acid (3,4-DHBA) in recombinant Escherichia coli using glucose and glycolic acid as feedstocks and briefly described their synthesis solely from glucose. Synthesis from glucose requires integration of the endogenous glyoxylate shunt with the 3,4-DHBA/3HBL pathway and co-overexpression of seven genes, posing challenges with respect to expression, repression of the glyoxylate shunt and optimal carbon distribution between the two pathways. Here we discuss engineering this integration. While appropriate media and over-expression of glyoxylate shunt enzymes helped overcome repression, two orthogonal expression systems were employed to address the expression and carbon distribution challenge. Synthesis of up to 0.3 g/L of 3HBL and 0.7 g/L of 3,4-DHBA solely from glucose was demonstrated, amounting to 24% of the theoretical maximum.National Science Foundation (U.S.). Synthetic Biology Engineering Research Center (Grant EEC-0540879)Masdar Institute of Science and Technology (Massachusetts Institute of Technology Cooperative Agreement 02/MI/MI/CP/11/07633/GEN/G/00

    STUDY OF ACTIVE FARMLAND USE TO SUPPORT AGENT-BASED MODELING OF FOOD DESERTS

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    Abstract. Food desert (FD) is the area that has limited access to affordable and nutritious foods such as fresh fruits, vegetables, and other healthful whole foods. FDs are important socio-economic problems in North Carolina (NC), potentially contributing to obesity in low-income areas. If farmland is available, local vegetable production could potentially help alleviate FDs. However, little is known about land use and land-use transitions (LUTs) in the vicinity of FDs. To fill this knowledge gap, we study the farmland use in three NC counties, Bladen, Guilford and, Rutherford, located in Coastal, Piedmont, and, Mountain regions of the state, respectively. The analysis combines the United States Department of Agriculture (USDA) 2015 FD/NFD delineation of census tracts, and geospatial soil productivity and 2008–2019 land cover data. The understanding of farmland use is expected to contribute to the development of LUT components of FD Agent-Based Models (ABM). </jats:p
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