Polymorphism plays an important role in the physical properties of organic crystals, including solid-state reactivity,1 optical and electronic properties,2'3 morphology, and solubility properties. For example, solid-state structure and morphology strongly affect the sensitization provided by photographic dyes and the crystal dissolution and bioavailability of pharmaceutical chemicals.4 The differing properties exhibited by polymorphs of a given compound can be attributed to variations in intraand intermolecular bonding and the corresponding packing motifs.5'6 The difference in packing energies among a given polymorphic family are typically small, and crystallization of a metastable polymorph is a consequence of kinetic selectivity during the nucleation and growth process.

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We examine the effect of different anions in solutions containing benzotriazole ͑BTA͒ on the Cu removal rate during chemical mechanical planarization ͑CMP͒. In solutions containing both Cl − and BTA, the Cu removal rate is nearly a factor of twenty lower than in solutions containing either Cl − or BTA alone. As-grown BTA films from solutions containing different anions are characterized using atomic force microscopy, ellipsometry, Raman spectroscopy, mass spectrometry, and open-circuit-potential measurements. Films grown from halide-containing solutions are found to be considerably thicker than those grown from other anions. The difference in Cu removal rate correlates well with the different as-grown film thicknesses.

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Modification of a traditional live-dead staining technique based on fluorescence microscopy has yielded an improved method capable of differentiating surface-immobilized antimicrobial agents from those agents acting via solution diffusion processes. By utilizing an inoculation chamber comprised of 50 mm polystyrene spheres as spacers between test substrate and coverslip control surfaces, three distinct bacterial cell populations can be probed by fluorescence microscopy for antimicrobial activity: (1) cells adhered to the coverslip, (2) cells adhered to the substrate, and (3) mobile cells in solution. Truly immobilized antimicrobial agents were found efficacious only at the substrate surface, while elutable agents were effective against all three populations. Glass surfaces derivatized with either quaternized poly dimethylaminoethylmethacrylate (pDMAEMA) or 3-(trimethoxysilyl) propyldimethyloctadecyl ammonium chloride (Si-QAC) were compared with bare glass control surfaces after contact and 4 h incubation with Staphylococcus aureus. pDMAEMA surfaces were both antimicrobial and immobilized, whereas the Si-QAC surfaces were only observed to be antimicrobial via active diffusion. In contrast to conventional thinking, Si-QAC surfaces showed no kill after removing all Si-QAC elutables via rinsing procedures. The semi-quantitative surface-separated live-dead staining (SSLDS) technique provides mechanistic insight and represents a significant improvement relative to current microbiological test methods for evaluating immobilized, antimicrobial agents.

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The goal of this work is to evaluate how emulsions in total nutrition admixtures are affected by the containers within which they are stored. Specifically, the study examines how the emulsion globule size distribution in different containers is related to adsorption or absorption of the lipids onto or into the container. The admixtures were prepared from a commercial lipid emulsion, 20% ClinOleic®, and the containers were either glass (borosilicate) or plastic (ethylene vinyl acetate, EVA). The large globule size distribution was monitored continuously for both containers over the course of 24 h, and the quantity of triglycerides taken up by both containers was measured by liquid chromatography. The lipid uptake by the EVA containers was also monitored by gravimetric methods. Briefly, the percent of fat globules greater than 5 micrometers (PFAT5) in EVA containers showed a 75% reduction compared to a marginal decrease of PFAT5 when in the glass container. Extraction of the lipids from the containers showed that the quantity of triglycerides associated with the EVA surfaces steadily increased with admixture exposure time, while the glass showed a significantly lower triglyceride content. Gravimetric measurements confirmed that the EVA containers gained measurable mass during exposure to the emulsion admixture.

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