Anode-supported solid oxide fuel cell with electrophoretic deposition-derived electrolyte operated under single-chamber conditions and a methane–air mixture

In this study, samaria-doped ceria (Sm_0.2Ce_0.8O_1.9, SDC) thin film is deposited on the Ni-SDC support by employing the electrophoretic deposition technique. Various factors are considered for the deposition of SDC films. The corresponding microstructure of the deposited SDC film is examined and correlated to the electrochemical performance as a single-chamber solid oxide fuel cell (sc-SOFC). It is found that the microstructure of the SDC film mainly relates to the particle size of SDC. After heat treatment, highly dense SDC film is obtained with the deposition condition of 5 g L⁻¹ of the SDC suspension (average grain size of SDC, 248 nm), 60 V as the applied potential, and the deposition time of 1 min (18 μm in thickness). For the Ni-SDC/SDC/SSC cell, an open circuit potential of 0.92 V and peak power density of 155 mW cm⁻² can be obtained at the furnace temperature of 500 °C.     

The present and future of biologically inspired adhesive interfaces and materials

The natural world provides many examples of robust, permanent adhesive platforms. Synthetic adhesive interfaces and materials inspired by mussels of genus Mytulis have been extensively applied, and it is expected that characterization and adaptation of several other biological adhesive strategies will follow the Mytilus edulis model. These candidate species will be introduced, along with a discussion of the adhesive behaviors that make them attractive for synthetic adaptation. While significant progress has been made in the development of biologically inspired adhesive interfaces and materials, persistent questions, current challenges, and emergent areas of research will be also be discussed.     

Effect of temperature and chain length on the bimodal emission properties of single polyfluorene copolymer molecules

Fluorescence emission spectra were recorded for isolated polymer chains of the polyfluorene copolymer, F8BT [poly(9,9-di-n-octylfluorene-alt-benzothiadiazole)], at 298 and 20 K for two molecular weights (chain lengths). For long-chain F8BT at 298 K, the observed distribution of single-molecule emission maxima G(Emax) is bimodal, with peaks at approximately 2.35 eV ("blue") and approximately 2.25 eV ("red"). Previously, the red forms have been assigned to polymer chains that possess intrachain contacts, which lowers the local singlet exciton energy. At approximately 20 K, G(Emax) collapses into a single broad distribution centered at approximately 2.3 eV for long-chain F8BT. However, this distribution can be further divided into a high-energy edge that is dominated by the "blue" form, while the remainder of the distribution is composed of the "red" form. Low-molecular-weight F8BT samples emit exclusively from the blue form, and no shift in peak maxima with low temperature was observed. A Franck-Condon analysis reveals a decrease in emitting state displacements between spectra measured at 298 and 20 K, suggesting that temperature-induced structural displacements are responsible for the change in the bimodal emission.     

A Novel Screening Method for Competitive FRET-Aptamers Applied to <Emphasis Type="Italic">E. coli</Emphasis> Assay Development

A novel high-throughput screening method is described in which a family of DNA aptamers selected against E. coli outer membrane proteins (OMPs) is subjected to PCR in the presence of fluorophore-dUTP conjugates using Deep Vent® exo- polymerase. The fluorophore-doped aptamers and their complementary strands are then heated to render them single-stranded and screened in filter well microtiter plates for fluorescence resonance energy transfer (FRET) assay potential. Using this system, a superior competitive FRET-aptamer designated EcO 4R was identified and the location of its putative binding pocket was determined by individually testing FRET potential in each of the secondary loop structures. By labeling the binding pocket with Alexa Fluor (AF) 647 and binding the aptamer to heavily Black Hole Quencher-3 (BHQ-3)-labeled E. coli bacteria, detection of as few as 30 live unlabeled E. coli per ml was achieved in a competitive displacement FRET assay format. The far red fluorescence emission enables detection in largely blue-green autofluorescent matrices. In addition, the competitive transfer of AF 647-EcO-4R aptamer to unlabeled E. coli cells after a 15 min equilibration period was verified by fluorescence microscopy. The present study also demonstrated that high aptamer affinity is not well correlated with competitive FRET potential.     

Determination of Arsenic in Drinking Water by Graphite Furnace Atomic Absorption Spectroscopy. An Undergraduate Instrumental Analysis Laboratory

A laboratory exercise, the analysis of arsenic in drinking water by graphite furnace atomic absorption spectroscopy (GFAA), is presented for use in an undergraduate instrumental methods course. The purpose of this GFAA exercise is to expose students to a practical and commonly used application, to provide students with hands-on experience with the instrument, and to reinforce concepts taught in the classroom. Students safely analyze a real-world sample containing an analyte in the parts-per-billion concentration range.     

Stabilization of Copper Catalysts for Liquid‐Phase Reactions by Atomic Layer Deposition

Atomic layer deposition (ALD) of an alumina overcoat can stabilize a base metal catalyst (e.g., copper) for liquid‐phase catalytic reactions (e.g., hydrogenation of biomass‐derived furfural in alcoholic solvents or water), thereby eliminating the deactivation of conventional catalysts by sintering and leaching. This method of catalyst stabilization alleviates the need to employ precious metals (e.g., platinum) in liquid‐phase catalytic processing. The alumina overcoat initially covers the catalyst surface completely. By using solid state NMR spectroscopy, X‐ray diffraction, and electron microscopy, it was shown that high temperature treatment opens porosity in the overcoat by forming crystallites of γ‐Al₂O₃. Infrared spectroscopic measurements and scanning tunneling microscopy studies of trimethylaluminum ALD on copper show that the remarkable stability imparted to the nanoparticles arises from selective armoring of under‐coordinated copper atoms on the nanoparticle surface.     

Statistical appearance of nonuniform fluctuations in a wide-gap n-n-n-n device

A cross-correlation matrix applied for restoring the doping profile in an n⁺-n⁻-n-n⁺ device was reported recently [Y.-H. Shiau, Solid-State Electron. 50 (2006) 191]. In this paper we will show that this statistical method is very useful for detecting the dynamical processes embedded in semiconductor devices. In addition, extraction of nonuniform fluctuations hidden in this wide-gap semiconductor device could be helpful for clarifying the previous studies on several competing instabilities in InSb at 77 K [A. ?enys, G. Lasiene, K. Pyragas, Solid-State Electron. 35 (1992) 975; H. Ito, Y. Ueda, Phys. Lett. A 280 (2001) 312]. A general discussion about the application of the cross-correlation matrix to other pattern-forming systems is also given in the present study.     

Longitudinal study of iodine in toenails following IV administration of an iodine-containing contrast agent

The literature on the relationship between diet and thyroid cancer (TC) risk and the higher incidence of TC among Asian immigrants to the US compared to second and third generation subgroups has prompted epidemiologists to hypothesize that increased levels of iodine consumption may be associated with TC risk, particularly among persons with a history of clinical or subclinical thyroid dysfunction. At the University of Missouri Research Reactor (MURR), we have applied epiboron neutron activation analysis to investigate human nails as a dietary monitor for iodine. Preliminary studies have indicated a positive correlation between dietary iodine intake and the concentration of iodine in toenails. However, these studies are confounded by high iodine levels (up to 30 ppm) in approximately 5% of the nails studied. We hypothesize that, in the subjects we have studied, the high iodine levels may be due to iodine-containing medications, in particular contrast-agents containing iopamidol. This paper will report on longitudinal studies using contrast agent subjects who were followed-up for almost two years compared to a longitudinal control and a population mean. Based on this study, we suggest that iodine-containing contrast agents contaminate nail samples via non-specific binding in the short term followed by incorporation in the nail as a result of absorption.     

Computational design of the sequence and structure of a protein-binding peptide

The de novo design of protein-binding peptides is challenging because it requires the identification of both a sequence and a backbone conformation favorable for binding. We used a computational strategy that iterates between structure and sequence optimization to redesign the C-terminal portion of the RGS14 GoLoco motif peptide so that it adopts a new conformation when bound to Gα(i1). An X-ray crystal structure of the redesigned complex closely matches the computational model, with a backbone root-mean-square deviation of 1.1 ?.