Using a microplate-based screening assay, the effects on Pseudomonas aeruginosa PAO1 biofilm formation of several S-substituted cysteine sulfoxides and their corresponding disulfide derivatives were evaluated. From our library of compounds, S-phenyl-L-cysteine sulfoxide and its breakdown product, diphenyl disulfide, significantly reduced the amount of biofilm formation by P. aeruginosa at levels equivalent to the active concentration of 4-nitropyridine-N-oxide (NPO) (1 mM). Unlike NPO, which is an established inhibitor of bacterial biofilms, our active compounds did not reduce planktonic cell growth and only affected biofilm formation. When used in a Drosophila-based infection model, both S-phenyl-L-cysteine sulfoxide and diphenyl disulfide significantly reduced the P. aeruginosa recovered 18 h post infection (relative to the control), and were non-lethal to the fly hosts. The possibility that the observed biofilm inhibitory effects were related to quorum sensing inhibition (QSI) was investigated using Escherichia coli-based reporters expressing P. aeruginosa lasR or rhIR response proteins, as well as an endogenous P. aeruginosa reporter from the lasI/lasR QS system. Inhibition of quorum sensing by S-phenyl-L-cysteine sulfoxide was observed in all of the reporter systems tested, whereas diphenyl disulfide did not exhibit QSI in either of the E. coli reporters, and showed very limited inhibition in the P. aeruginosa reporter. Since both compounds inhibit biofilm formation but do not show similar QSI activity, it is concluded that they may be functioning by different pathways. The hypothesis that biofilm inhibition by the two active compounds discovered in this work occurs through QSI is discussed.

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The process of chemical mechanical planarization (CMP) employed by the semiconductor industry creates large quantities of wastewater containing toxic levels of copper. Use of biomass-based filtration may offer a less expensive and more sustainable means of treating wastewater prior to disposal. We screened a library of microorganisms for ability to bind Cu 2+ from solution and form biofilm within packed bed filtration columns. Filter beds supporting L. casei/P. pastoris biofilms were found to exhibit a two-phase adsorption behavior during flow-through binding experiments. Bound Cu 2+ was able to be recovered via acid wash, and the biomass quickly regenerated and could be reused.

Through inline processing of a prospective Spin on Hardmask (SOH) material, bubble defects were observed randomly across a wafer. Several complementary FA techniques were utilized to characterize the bubble defects including SEM, TEM, and chemical analysis techniques. The root cause of defect formation was identified as a raw material imperfection in SOH, which led to excessive outgassing. Imperfections within the substrate formed nucleation sites for outgassing of SOH material forming bubbles, which allowed voids to propagate. These findings led to implementation of greater quality control methods by the raw material manufacturer.

Summary. Mycoplasma fermentans organisms in medium containing 20% horse serum multiplied to 107-101* ccu/ml within 5 days at 37°C and were dead usually after 9 days. There was no growth in medium without serum, nor in such medium with the addition of cholesterol or palmitic acid or both, but in some experiments addition of bovine plasma albumin (BPA) increased the number of organisms by up to 1000-fold and some remained viable for up to 84 days. BPA and cholesterol or BPA, palmitic acid and cholesterol more often enhanced growth, in terms of the maximum number of organisms and their survival, than did the addition of BPA alone. The maximum number of organisms in such supplemented serum-free media was usually at least ten-fold less than in medium with horse serum, but some organisms remained viable for up to 13 1 days. Survival of Ureaplasma ureazyticum was also longer in the supplemented serumfree medium than in standard horse-serum medium. The possible factors affecting persistence of mycoplasmas in culture are discussed in relation to these observations.

Chemically amplified resist (CAR) materials are widely used in advanced node patterning by extreme ultraviolet lithography (EUVL). To support the continuous requirement of reducing critical dimension (CD), CAR has been designed to process at tens of nanometer coating thickness while taking into consideration film roughness, aspect ratio, and etch transfer challenge. In this study, we investigated the impact of the photoresist’s different spin speed for same film thickness on resolution, line width roughness, and sensitivity (RLS) trade-off for Line and Space (L/S) patterns. We selected photoresists with identical chemical composition that differed only in total wt solid% in the solution. Photoresist films at constant thickness were investigated for the spin speed impacts on photoresist film density, hydrophobicity on the film surface, and film surface roughness. The corresponding EUV lithographic performance will be presented.