Acidity in crude oils has long been a problem for refining. Knowledge of the detailed chemical composition of the acids responsible for corrosion can facilitate identification of problem crude oils and potentially lead to improved processing options for corrosive oils. A highly aerobically biodegraded crude from the San Joaquin Valley, which has a long history of causing corrosion problems during refining, was the subject of this study. The oil was first extracted with base, then acidified and extracted with petroleum ether. A portion of the resulting acid fraction was methylated. The unmethylated extract was analyzed by FTIR, NMR, and the methylated sample was analyzed by high-resolution mass spectrometry (HRMS). Over 96% of the ions observed in HRMS have been assigned reliable formulas. Considerably greater functionality is seen in this sample than would be presumed from the "naphthenic acid" title typically assigned to these species. Although over 60% of the compounds contained two or more oxygens, compounds containing only oxygen heteroatoms accounted for less than 10% of the acidic compounds identified. Approximately one-half of the species contained nitrogen and about one-fourth contained sulfur. It is believed that microbial degradation is a major source of these acidic components. It was also observed that acid species with higher degrees of heteroatom substitution generally also had a higher degree of saturation than those species having less heteroatoms, possibly due to impeded migration of highly substituted, less-saturated species.

CD47 is a transmembrane protein that is a marker of “self”. CD47 binding to its cognate receptor in leukocytes and macrophages, signal regulatory protein alpha (SIRPα), causes inhibition of inflammatory cell attachment. We hypothesized that immobilization of recombinant CD47 on polymeric surfaces would reduce inflammation. Recombinant CD47 was appended to polyvinyl chloride (PVC) or polyurethane (PU) surfaces via photoactivation chemistry. Cell culture studies showed that CD47 immobilization significantly reduced human neutrophil (HL-60) and human monocyte derived macrophage (MDM) (THP-1) attachment to PVC and PU respectively. A neutralizing antibody, directed against SIRPα, inhibited THP-1 and HL-60 binding to PU and PVC surfaces respectively. This antibody also increased the level of SIRPα tyrosine phosphorylation, thereby indicating a direct role for SIRPα mediated signaling in preventing inflammatory cell attachment. Studies using human blood in an ex vivo flow-loop showed that CD47 modified PVC tubing significantly reduced cell binding and neutrophil activation compared to unmodified tubing or poly-2-methoxy-ethylacrylate (PMEA) coated tubing. In ten-week rat subdermal implants, CD47 functionalized PU films showed a significant reduction in markers of MDM mediated oxidative degradation compared to unmodified PU. In conclusion, CD47 functionalized surfaces can resist inflammatory cell interactions both in vitro and in vivo.

The morphological and inflammatory responses of adherent macrophages are correlated to evaluate the biocompatibility of surfaces. Monocyte derived macrophage, THP-1, and THP-1 cells expressing GFP-actin chimeric protein were seeded onto glass, polyurethane (PU), and glass surface modified with quaternary ammonium salt functionalized chitosan (CH-Q) and hyaluronic acid (HA). Using confocal microscopy, the surface area, volume and 3-D shape factor of adherent macrophages was quantified. For comparison, functional consequences of cell-surface interactions that activate macrophages and thereby elicit secretion of a pro-inflammatory cytokine were evaluated. Using an enzyme linked immune sorbent assay, tumor necrosis factor-alpha (TNF-α) was measured. On glass, macrophages exhibited mainly an amoeboid shape, exhibited the largest surface area, volume, and 3-D shape factor and produced the most TNF-α. On PU, macrophages displayed mainly a hemispherical shape, exhibited an intermediate volume, surface area and 3-D shape factor, and produced moderate TNF-α. In contrast, on CH-Q and HA surfaces, macrophages were spherical, exhibited the smallest volume, surface area, and 3-D shape factor, and produced the least TNF-α. These studies begin to validate the use of GFP-actin modified MDM as a novel tool to correlate cell morphology with inflammatory cell response.

This paper is an initial study of the reactivity and thermal stability of atomic platinum clusters supported on Al 2 O 3 /SiO 2 /Si(100) as a function of the thickness of the alumina film and presence of hydrogen. Extremely high thermal stability of Pt 7-10 clusters in vacuo as well as in the presence of hydrogen is observed on SiO 2 /Si(100) coated with six cycles of Al 2 O 3 film prepared by an atomic layer deposition technique.

Sintering of supported nanocatalysts often leads to the loss of the catalytic activity and selectivity. This paper reports on synchrotron X-ray studies of the thermal stability of supported platinum nanoparticles produced by cluster deposition on the naturally oxidized surface of a silicon wafer (SiO 2 /Si(111)). The temperature region of aggregation was determined by gradually heating the samples up to above 400 °C, and recording two-dimensional in situ X-ray scattering images during the heat treatment. The data analysis reveals an unexpectedly high stability of the supported particles, which preserve their original size up to about 320 °C, at which an abrupt onset of the agglomeration takes place.