Postsynthetic Functionalization of Mg-MOF-74 with Tetraethylenepentamine: Structural Characterization and Enhanced CO Adsorption.

Postsynthetic functionalization of magnesium 2,5-dihydroxyterephthalate (Mg-MOF-74) with tetraethylenepentamine (TEPA) resulted in improved CO adsorption performance under dry and humid conditions. XPS, elemental analysis, and neutron powder diffraction studies indicated that TEPA was incorporated throughout the MOF particle, although it coordinated preferentially with the unsaturated metal sites located in the immediate proximity to the surface. Neutron and X-ray powder diffraction analyses showed that the MOF structure was preserved after amine incorporation, with slight changes in the lattice parameters.

Bromine-catalyzed conversion of CO2 and epoxides to cyclic carbonates under continuous flow conditions.

A continuous method for the formation of cyclic carbonates from epoxides and carbon dioxide (CO2) is described. The catalysts used are inexpensive and effective in converting the reagents to the products in a residence time (t(R)) of 30 min. The cyclic carbonate products are obtained in good to excellent yield (51-92%).

DNA-directed assembly microarray for protein and small molecule inhibitor screening.

A robust high-throughput and high-fidelity screening platform for identifying and validating potential target molecules is the key for drug development. During the past decade, microarray platforms have demonstrated enormous potential for developing robust tools for small molecules as well as protein-based drug discovery and analysis. Recently, we developed a DNA-directed assembly microarray platform with improved screening and immobilization strategies.

Isoprenoid pathway optimization for Taxol precursor overproduction in Escherichia coli.

Taxol (paclitaxel) is a potent anticancer drug first isolated from the Taxus brevifolia Pacific yew tree. Currently, cost-efficient production of Taxol and its analogs remains limited. Here, we report a multivariate-modular approach to metabolic-pathway engineering that succeeded in increasing titers of taxadiene--the first committed Taxol intermediate--approximately 1 gram per liter (~15,000-fold) in an engineered Escherichia coli strain.

Formation of magnetic nanotubes by the cooperative self-assembly of chiral amphiphilic molecules and Fe3O4 nanoparticles.

Single- and double-walled magnetic nanotubes are obtained in a one-step liquid phase reaction by the cooperative self-assembly of chiral amphiphiles and nanoparticles on cooling of heated mixtures of N-dodecanoyl-L-serine and Fe(3)O(4) nanoparticles in toluene. The nanotubes are composed of well-ordered, close-packed nanoparticle assemblies, and can be transformed into chiral magnetic nanostructures, such as helical coils, by subsequent calcination. The nanoparticle assemblies and their variations on calcination are attributed to the collective organization of the surfactant molecules adsorbed on the nanoparticles and the freely dispersed chiral molecules, and the dewetting effects guided by the primitive constitution of the chiral amphiphilic molecular assemblies.

Analysis of polyhydroxybutyrate flux limitations by systematic genetic and metabolic perturbations.

Poly-3-hydroxybutyrate (PHB) titers in Escherichia coli have benefited from 10+ years of metabolic engineering. In the majority of studies, PHB content, expressed as percent PHB (dry cell weight), is increased, although this increase can be explained by decreases in growth rate or increases in PHB flux. In this study, growth rate and PHB flux were quantified directly in response to systematic manipulation of (1) gene expression in the product-forming pathway and (2) growth rates in a nitrogen-limited chemostat.