Formation of three-dimensional ordered hierarchically porous metal oxides via a hybridized epoxide assisted/colloidal crystal templating approach.

Three-dimensionally ordered hierarchically porous alumina, iron(III) oxide, yttria, and nickel oxide have been prepared through the hybridization of colloidal crystal-templating and a modified sol-gel method. Simply, highly ordered arrays of poly(methyl methacrylate) (PMMA) were infiltrated with a precursor solution of metal salt and epoxide. Calcination after solidification of the material removed the polymer template while forming the inverse replicas, simultaneously. These hierarchical structures possessing macropore windows and mesopore walls were characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and N2 adsorption/desorption techniques to probe the structural integrity. It was revealed by PXRD that the prepared 3D frameworks were single-phase polycrystalline structures with grain sizes between 5 and 27 nm. The thermal stability as studied by TGA illustrates expected weight losses and full decomposition of the PMMA template. SEM reveals the bimodal, hierarchical macroporous frameworks with well-defined macropore windows and mesoporous walls. Gas sorption measurements of the ordered materials display surface areas as high as 93 m(2) g(-1), and average mesopore diameter up to 33 nm. Due to the versatility of this method, we expect these materials will be ideal candidates for applications in catalysis, adsorption, and separations. Furthermore, the implementation of this technology for production of three-dimensionally ordered macroporous materials can improve the cost and efficiency of metal oxide frameworks (MOFs) due to its high versatility and amenability to numerous systems.

Thermoelectric properties of porous multi-walled carbon nanotube/polyaniline core/shell nanocomposites.

Porous polyaniline (PANI)-coated multi-walled carbon nanotube (MWNT) core/shell nanohybrids were fabricated through in situ polymerization and subsequently assembled into macroscopic composites. N(2) adsorption/desorption analysis indicated that the volume of nanopores increased significantly, which could make a significant contribution to phonon scattering. Thermal annealing was also carried out to improve the Seebeck coefficient of the as-produced nanocomposites. The optimal sample showed electrical conductivity of 14.1 S cm(-1), a Seebeck coefficient of 79.8 µV K(-1) and thermal conductivity of 0.27 W mK(-1), resulting in a highest figure of merit (ZT) of 0.01 at a very low loading of MWNTs (<1 wt%). These results will provide a potential direction to enhance thermoelectric performance of organic materials and also facilitate the application of organic materials in thermal energy harvesting or cooling.

A fluorescent dipyrrinone oxime for the detection of pesticides and other organophosphates.

An N,N-carbonyl-bridged dipyrrinone oxime has been synthesized and studied as a potential sensor for organophosphates. The molecular sensor underwent a drastic colorimetric response upon formation of the adduct. The pesticide dimethoate was found to produce the biggest spectral response, with a limit of detection equal to 4.0 ppm using UV-visible spectroscopy. Minimal fluorescence "turn on" via a PET mechanism was seen, and molecular modeling studies were used to explain the lower than expected PET response. The X-ray crystal structure of the fluorescent dipyrrinone oxime was also obtained.

PLGA microparticles encapsulating prostaglandin E1-hydroxypropyl-ß-cyclodextrin (PGE1-HPßCD) complex for the treatment of pulmonary arterial hypertension (PAH).

PURPOSE: To test the efficacy and viability of poly (lactic-co-glycolic acid) (PLGA) microspheres encapsulating an inclusion complex of prostaglandin E(1) (PGE(1)) and 2-hydroxypropyl-ß-cyclodextrin (HPßCD) for pulmonary delivery of PGE(1) for treatment of pulmonary arterial hypertension (PAH), a disease of pulmonary circulation. METHODS: PLGA-based microparticulate formulations of PGE(1)-HPßCD inclusion complex or plain PGE(1) were prepared by a double-emulsion solvent evaporation method. HPßCD was used as a complexing agent to increase the aqueous solubility of PGE(1), act as a porosigen to produce large porous particles, and promote absorption of PGE(1). Particles were characterized for micromeritic properties, in vivo absorption, metabolic degradation, and acute safety. RESULTS: Incorporation of HPßCD in the microparticles resulted in development of large particles with internal pores, which, despite large mean diameters, had aerodynamic diameters in the inhalable range of 1 to 5 µm. HPßCD incorporation also resulted in a significant increase in the amount of drug released in vitro in simulated interstitial lung fluid, showing a desirable burst release profile required for immediate hemodynamic effects. Compared to plain PLGA microparticles, entrapment efficiency was decreased upon complexation with HPßCD. In vivo absorption profile indicated prolonged availability of PGE(1) in circulation following pulmonary administration of the optimized microparticulate formulations, with an extended half-life of almost 4 hours. Metabolic degradation and acute toxicity studies suggested that microparticulate formulations were stable under physiological conditions and safe for the lungs and respiratory epithelium. CONCLUSIONS: This study demonstrates the feasibility of PGE(1)-HPßCD complex encapsulated in PLGA microparticles as a potential delivery system for controlled release of inhaled PGE(1).

Conformational and configurational analysis of an N,N carbonyl dipyrrinone-derived oximate and nitrone by NMR and quantum chemical calculations.

The geometries and relative energies of new N,N carbonyl dipyrrinone-derived oxime molecules (E/Z-s-cis 4a and E/Z-s-cis 4b) have been investigated. The calculated energies, molecular geometries, and (1) H/(13) C NMR chemical shifts agree with experimental data, and the results are presented herein. The E-s-cis conformations of 4a and 4b and the Z-s-cis conformation of 5b were found to be the thermodynamically most stable isomers with the oxime hydrogen atom or the methyl functional group adopting an anti-orientation with respect to the dipyrrinone group. This conformation was unambiguously supported by a number of 2D NMR experiments.