Oxygen-transfer enhancement has been observed in the presence of colloidal dispersions of magnetite (Fe3O4) nanoparticles coated with oleic acid and a polymerizable surfactant. These fluids improve gas−liquid oxygen mass transfer up to 6-fold (600%) at nanoparticle volume fractions below 1% in an agitated, sparged reactor and show remarkable stability in high-ionic strength media over a wide pH range. Through a combination of experiments using physical and chemical methods to characterize mass transfer, it is shown that (i) both the mass transfer coefficient (k L) and the gas−liquid interfacial area (a) are enhanced in the presence of nanoparticles, the latter accounting for a large fraction of the total enhancement (80% or more), (ii) the enhancement in k L measured by physical and chemical methods is similar and ranges from 20 to 60% approximately, (iii) the enhancement in k L levels off at a nanoparticle volume fraction of approximately 1% v/v, and (iv) the enhancement in k L a shows a strong temperature dependence. These results are relevant to a wide range of processes limited by the mass transfer of a solute between a gas phase and a liquid phase, such as fermentation, waste treatment, and hydrogenation reactions.

We report a new method to prepare ultrathin blocklike copolymer films on metal surfaces with molecularly optimized surface and barrier properties. Copolymer films containing various fluorocarbon and/or hydrocarbon side chains were created by a one-step surface-initiated polymerization of poly-(hydroxyethyl methacrylate) (PHEMA) followed by straightforward derivatization steps. Exposure of PHEMA to perfluorobenzoyl chloride results in a perfluoroaryl-modified PHEMA film that exhibits high conversion and outstanding barrier properties but does not present an oleophobic surface. We have previously demonstrated that fluorinated esters created in this manner may be hydrolyzed back to PHEMA by brief exposure to base. Controlled hydrolysis results in regeneration of PHEMA in the outer surface region that can be subsequently rederivatized with alkyl or fluoroalkyl acid chlorides to create copolymer films with tailored surface composition. Surface properties are solely affected by the species used during rederivatization while barrier properties result from the combined conversion, structuring, and surface properties of the copolymer film.

Glioblastomas display variable phenotypes that include increased drug-resistance associated with enhanced migratory and anti-apoptotic characteristics. These shared characteristics contribute to failure of clinical treatment regimens. Identification of novel compounds that promote cell death and impair cellular motility is a logical strategy to develop more effective clinical protocols. We recently described the ability of the small molecule, KCC009, a tissue transglutaminase (TG2) inhibitor, to sensitize glioblastoma cells to chemotherapy. In the current study, we synthesized a series of related compounds that show variable ability to promote cell death and impair motility in glioblastomas, irrespective of their ability to inhibit TG2. Each compound has a 3-bromo-4,5-dihydroisoxazole component that presumably reacts with nucleophilic cysteine thiol residues in the active sites of proteins that have an affinity to the small molecule. Our studies focused on the effects of the compound, ERW1227B. Treatment of glioblastoma cells with ERW1227B was associated with both down-regulation of the PI-3 kinase/Akt pathway, which enhanced cell death; as well as disruption of focal adhesive complexes and intracellular actin fibers, which impaired cellular mobility. Bioassays as well as time-lapse photography of glioblastoma cells treated with ERW1227B showed cell death and rapid loss of cellular motility. Mice studies with in vivo glioblastoma models demonstrated the ability of ERW1227B to sensitize tumor cells to cell death after treatment with either chemotherapy or radiation. The above findings identify ERW1227B as a potential novel therapeutic agent in the treatment of glioblastomas.